Dissertations / Theses on the topic 'Construction output'
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1
Lowe, John G. "Construction productivity : an input-output approach." Thesis, Heriot-Watt University, 1993. http://hdl.handle.net/10399/1441.
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This Thesis describes an approach to the development and testing of a model that can compare construction performance across time, space, and economic system. Labour and capital productivity measures as well as the multi-factor approach were evaluated. Capital productivity alone, as a 'pure' financial ratio, appears able to deal with the key problems posed by indexation, to deal with inflation for time-series comparisons, and fluctuating currency exchange rates, for international comparisons. The major flaws with traditional capital productivity measures, particularly the problems inherent in valuing the 'capital' employed in a given industry or sector, are discussed and the model is developed to meet the objections. The notion of capital productivity employed in the model, while in computational terms similar to the traditional approach, is different in philosophical terms. Thus instead of than attempting to 'value' the capital employed in the productive process, the cost of capital 'sunk' is valued making allowance for notional depreciation based on the balance of the different types of assets employed. The discount rate emerges by counterpoising the discounted value of anticipated future profits against the historic cost of investment sunk into the current stock of capital goods. There are problems specific to construction, in particular the incidence of off-site prefabrication and plant hire, which tend to make traditional capital productivity largely irrelevant to the construction process. An input-output framework is used to examine the productivity involved in the total building process as opposed to the on-site activities. In addition, the problems of incompatibility across economic systems manifested in such issues as differential rates of indirect taxation etc., is allowed for by adjusting the price levels from market prices to 'eigenprices' an input-output based approach. The resulting model is tested via an inter-industry time-series Case Study of the UK over the period 1948 to 1990 using six broad industrial groupings. The strengths and weaknesses of the approach are discussed in the light of the Case Study results.
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Hairstans, Robert. "Optimisation of timber platform frame construction." Thesis, Edinburgh Napier University, 2007. http://researchrepository.napier.ac.uk/Output/6041.
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Timber platform frame has evolved as an efficient method of construction for domestic dwellings and is experiencing continual growth in the UK due to it lending itself to off-site modem methods of construction (MMC), being environmentally efficient and exhibiting structural robustness. The challenge faced by the industry in the UK is to continue the evolutionary process such that the future demands of off-site MMC and regulatory changes are met. By conducting a study of the development of timber platform frame construction and reviewing the current and future requirements of the domestic dwelling construction market the challenges for the industry were highlighted. The business drivers of a timber platform frame manufacturer were considered and in conjunction with the information from the review an agenda of research programmes was derived. The objective of the research, although primarily from a structural timber engineering perspective, was to address the challenges faced by the industry employing a holistic approach with a view to implementing applied research. The UK procurement process for domestic dwelling construction is such that building layout is determined by architectural requirements. Building layout can have an adverse effect on structural stability and result in an inefficient system. A design review was conducted to determine the influencing factors which impinge upon system stability as a result of which recommendations for improvements were made. From the investigation the transfer of shear from a wall diaphragm to the foundation was deemed critical. Therefore, an experimental study was carried out which has resulted in an optimised specification. Further to this mathematical modelling techniques were used to demonstrate the impact that architectural layout has on stability, quantifying the financial penalty of inefficient layout and making recommendations to improve current designs. One of major priorities of the UK Government is to reduce climate change by implementing a low carbon economy with sustainable production and consumption; all with duty of care towards natural resources. Improvements to the Building Regulations (2006), in conjunction with other requirements, will result in wall U-values in domestic dwellings to be between 0.27 to 0.30W/m2K. To determine an efficient method of meeting the new regulations an all encompassing research programme was conducted with the primary function being to develop a sustainable method of achieving thermal efficiency. Another method of wall construction is Structural Insulated Panels (SIPs) and this option was reviewed. Initial work by Kermani (2005) on the structural performance of SIPs was extended to examine their racking characterisitcs with comparative studies to European and British structural codes of practice carried out. One of the key industry drivers which the review highlighted was the need for the implementation of lean technologies. The fabrication of flitch beams (timber-steel-timber sandwich configuration), used in cases of onerous load span conditions and limited depth of section, was improved through the implementation of a shot fired dowel connection method. To optimise the method of fabrication and achieve implementation an extensive laboratory study was carried out the results of which are compared to European structural codes of practice with recommendations made for design. The implementation of off-site MMC methods results in a change in associated risk during construction from minor consequence and high risk to major consequence and low risk. The crane erect method of timber platform frame construction optimises on-site performance in terms of both time and cost and reduces the requirement of working at height, which on average causes almost one fatality every week. The biggest health and safety risk associated with the crane erect method is failure of the roof system when being lifted into position. Using an analytical model, verified by full scale laboratory testing, a range of lifting conditions were researched and a best practice lifting procedure was developed which allows the safe lifting of standard roof systems used in domestic dwelling construction.
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Sanna, Fausto. "Timber modern methods of construction : a comparative study." Thesis, Edinburgh Napier University, 2018. http://researchrepository.napier.ac.uk/Output/1256099.
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The doctoral research revolves around a comparative study of timber modern methods of construction for low-rise, residential buildings in Scotland. The building techniques studied involve both timber-frame panel construction (open-panel and closed-panel systems and structural insulated panels) and massive-timber construction (cross-laminated and nail-laminated timber panels). A non-timber technique is also included in the study: more traditional, load-bearing masonry (blockwork). These different building techniques have been analysed from two complementary aspects: environmental impacts and thermal performance. The environmental study is based on the life-cycle assessment methodology and embraces various aspects: environmental impacts (e.g., climate change, acidification, eutrophication, ozone depletion, etc.), consumption of energy (renewable and non-renewable resources) and production of waste (from non-hazardous to radioactive). The assessment takes a cradle-to-gate approach and, in its structure and method, is informed by the current recommendations of the international standards in the field (i.e., ISO 14040 series). Various environmental trade-offs between construction methods have been identified. In terms of global-warming potential (excluding biogenic carbon sequestration), results suggest that timber-frame buildings show a better performance than masonry buildings; this is particularly true for the open-panel system, which emits about 10% less carbon than the masonry counterpart. Massive-timber buildings tend to cause more carbon emissions than masonry ones. In terms of consumption of non-renewable primary energy, timber buildings do not generally show significant advantages with respect to blockwork-based masonry. In particular, structural-insulated panel systems tend to show very high energy requirements. Timber-based buildings show a tendency to cause increased acidification, eutrophication and creation of low ozone than their masonry counterpart. The level of offsite fabrication that is employed for the erection of the buildings plays an important role in the magnitude of most environmental impacts, which show an average decrease between 5% and 10% when some of the operations are shifted from the construction site to the factory. v The thermal study investigates the performance of the building envelope, and, in particular, of external walls, by means of tests whereby the thermal behaviour of a sample of walls (of full-size section) has been observed and measured over time. On the outside, the walls were exposed to real, natural weather variations throughout the summer. The study especially focuses on the time-dependent response of three different walling systems (which results from their individual cross-sectional arrangements of building components and the associated combination of heat-storage capacity and thermal resistance): a timber-framed wall, a cross-laminated-timber wall and a masonry wall. Thus, the main goal of the study was to characterise the thermal-inertia parameters of these walls. This type of thermal behaviour is related to the repercussions of global climate change at UK level, especially in terms of increase in solar irradiance and temperature, which requires an adaptation of the building-envelope such that it can perform well both during wintertime and summertime, by providing maximum indoor comfort with minimum economic and environmental costs from the construction and operation of buildings. The timber-framed wall possesses the greatest capacity to slow down the propagation of temperature waves from the outer surface to the inner surface (time lag), whereas the masonry wall performs best with respect to reducing the amplitude of temperature oscillation on the inner surface (decrement factor). The cross-laminated-timber wall exhibits intermediate values of both time lag and decrement factor, relative to the other two walls. Both the thermal and life-cycle assessment of the construction alternatives aim at assisting the design and decision-making process in the residential field and at suggesting areas that need to be addressed and improved, towards a coherent evolution of the building techniques included in this study and a step forward in the realisation of sustainable, low-rise dwellings.
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Taylor, Mark D. "Economic appraisal and risk analysis of construction automation." Thesis, Edinburgh Napier University, 2003. http://researchrepository.napier.ac.uk/Output/4278.
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Elsayah, Othoman S. "A framework for improvement of contractor selection procedures on major construction project in Libya." Thesis, Edinburgh Napier University, 2016. http://researchrepository.napier.ac.uk/Output/453191.
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The construction sector constitutes one of the most important sectors in the economy of any country. Contractor selection is a critical decision that is undertaken by client organisations and is central to the success of any construction project. For major construction projects, final contractor selection often follows the contractor selection stage. Contractor selection is a process which involves investigating, screening and determining whether candidate contractors have the technical and financial capability to be accepted to formally tender for construction work. The process should be conducted prior to the award of contract, characterized by many factors such as: contactor's skills, experience on similar projects, track- record in the industry, and financial stability. Several models and approaches have been developed to assist client organisations in the contractor selection decision making process. This thesis evaluates the current state of knowledge in relation to contractor selection models. The key features, strengths and limitations of each of these methods are critically evaluated. The key factors of particular interest to client organisations are assessed. This thesis reports on-going research which aims to develop improved contractor selection criteria and methods with specific application to make construction projects in the Libyan context. The aim of this thesis is to build a framework for contractor selection process in the Libyan Construction Industry (LCI) and to find out the major obstacles constraining its operations which so far have not yet been taken into account by the Libyan researchers. However, to address that, a huge investigation has taken place about the current statues for contractor selection in Libya, as well as, in developed and well developed countries. To achieve that, both, theoretical and empirical research was carried out between 2010 and 2013 in Libya. The theoretical study concentrated on the sector of construction industry (Cl) and its key issues, whereas the empirical study focused and explored on the Libyan Construction Industry (LCI) as the context for the study. Two case studies were utilized in this research. The case studies were used to provide more information about the current situation of the LCI and to identify the contractor selection procedures of construction projects in. Also, it assist the researcher to identify key research questions that can later be used in a questionnaire survey. This research was implemented through the administration of a questionnaire survey based on research questions that are required for the building of a framework for contractor selection procedure and the identification of the challenges and obstacles that are facing the clients in the selection process. The development of the framework includes, but is not limited to, contractor selection criteria, decision makers, consultant, clients and sub-contractor. Therefore, the data collection is based on responses from the public and private sector (clients, consultants, contractors and others that are involved in and are knowledgeable about the contractor selection process in the Libyan construction projects). Mean and analysis of variance (independent T-test) were used to manipulate the data from the questionnaire within the SPSS v.20 software environment. The resulting framework was subjected to a validation procedure which involved a structured Delphi technique process based on a focus group consisting of experts who were selected to help with validation of the framework and establishing the extent to which the framework is practical, clear, applicable and comprehensive. This research uses an integrated approach that combines AHP (Analytic Hierarchy Process) method and TOPSIS (Technique for Order Performance by Similarity to Ideal Solution) method to evaluate and investigate the current existing practice of contractor selection in Libya. Also, the Delphi technique was used to establish a road map for contractor selection process. Twelve participants were selected to help with validation of the framework. Overall, this research found that the LCI was suffering from a total absence of contractor selection frameworks. This directly impacts on client satisfaction as well as government planning in the reconstruction of the country after the civil war in particular. To close this gap, this research was embarked upon to identify and explore the various contractor selection methods and frameworks that are utilized to support the guidance of contractor selection process toward success. As a consequence of this study, the Contractor Selection Process (CSP) is now very comprehensive and can now be a reference for any problem. Furthermore, this research will help decision makers and others involved to be more aware of and have a better understanding of the selection procedure in the LCI. This new understanding will help decision makers to make more efficacious decisions and to adopt good short and long term policies for contractor selection planning which can then be put into procedure. Even though this framework is built for the LCI, the research can be utilised in other countries that have a similar construction industry environment.
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Schrapers, Manuel. "Applying standards, guidelines and methods in construction project management." Thesis, Edinburgh Napier University, 2018. http://researchrepository.napier.ac.uk/Output/1253601.
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This dissertation scrutinizes the application of various standards, guidelines and methods in construction project management, and examines the use of such methods, tools and applications. Even though the availability of literature in the context of PM is extensive there has not been an adequate focus on applied project management with a specific interest in the constructing project management. This study describes the experiences gathered by the interviewees who are experienced construction executives and also discusses how they have managed their projects. The reason for the selection of a subjective, descriptive and phenomenal research approach is described and the advantages for this philosophical stance are also mentioned in the thesis. The question that emerges is in regards with how the construction managers accomplish any given project and how they ‘live' their PM. Hence, this study investigated the relevance of PM for managers working on construction projects. Various techniques, methods and procedures which were not included in the literature were highlight by the participants. There are studies available, mainly empirical, in the context of applied PM methods and the results of these studies do not correspond with the findings of this research. Another finding is that, in general, from the responses received, it is clear that PM certification programmes provide limited value to an experienced construction manager. Further results were summarized in the findings and result chapter of this work.
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Coste, Guillaume. "The assessment and applications of a new connector type for use in timber structural systems." Thesis, Edinburgh Napier University, 2010. http://researchrepository.napier.ac.uk/Output/4407.
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Edwards, Andrew J. "Properties of hydraulic and non-hydraulic limes for use in construction." Thesis, Edinburgh Napier University, 2005. http://researchrepository.napier.ac.uk/Output/6884.
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The term "lime" comes from the word limestone. Limestone rocks were converted to lime powder by burning (calcining). The process of converting limestone to lime was an old process and it has been well documented, archaeologically. It has been established that the production of lime is the oldest industrial process can"ied out by humankind, dating back thousands of years. In fact, 3650 years ago Moses instructed the people of Israel, after they crossed the Jordan River, to set up large stones and whitewash them with lime and write the laws of God in lime. Lime was the most commonly used cementatious binder until about a century ago, when its use started to decline. It was replaced by Portland cement, a material essentially developed for structural purposes in the era of the industrial revolution. Portland cement has certain advantages over lime. The material develops strength and hardens faster for work to be carried out at a greater pace with better quality control and agreed standards. It has now become the dominant cementitious binder, part of it due to aggressive marketing of the material by the manufacturers. The use of Portland cement in the restoration and conservation of old buildings and structures in the UK over the past few years has resulted in a series of problems and cost millions of Pounds to eradicate. The decline in the use of lime in many countries has not only caused a diminution of its production, but has also contributed to a gradual disappearance of the traditional skills required both to produce a high quality product and to use it in construction. Therefore it is necessary to reintroduce and revive the old tradition of using lime by providing more information about its production and use. At present there are no comprehensive standards or code of practices, British or European to aid engineers and contractors in the use of hydraulic and non hydraulic limes in construction. BS EN 459 (2001) gives guidance on the chemical and physical properties of limes but it does not provide vital information about lime-based mortars e.g. mix proportions, mixing process, bond with masonry units, curing methods and all other necessary aspects to assess in the use of the material in construction. At present it is very easy for engineers, contractors and consultants to misuse lime mortars in new construction or in restoration and conservation of old buildings. Part of the decline in production of lime and reluctance of use in construction is due to the lack of understanding of the material properties and its performance in structures. Therefore it is necessary to examine and revive the old tradition in using lime mortars in construction and look at the new technologies used presently in the production process in order to provide the necessary background and information to aid the use of the material The present study provides a literature review, test results, discussions, conclusions and background information to set up standards in the production and use of hydraulic and non-hydraulic limes and their mortars in the construction of new buildings and the restoration and conservation of old buildings. Hydraulic and non-hydraulic limes have an excellent track record in buildings through history but their use in the UK was missed for some thirty years or more. Part of the reason for undertaking this research programme was to examine the properties of pre-packaged hydraulic limes available in the market at present. The properties of limes vary considerably dependent on the raw materials, composition and manufacturing process. The results of this study showed that there was a great variation in the properties and performance of limes and their mortars. The results also showed that the properties of lime mortar improved by adding different percentages of POliland cement. The research examined the effect of sand grading on the lime mortars compreSSIve, splitting and brick/mortar bond strength. The thesis also investigated the effects of using different casting moulds and curing methods on mortar strength. The results showed that the porosity of lime mortar was one of the reasons it was a success in the past and why it was so important nowadays to use it in the restoration and conservation of historic buildings.
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Ridley-Ellis, Daniel. "Rectangular hollow sections with circular web openings : fundamental behaviour in torsion, bending and shear." Thesis, University of Nottingham, 2000. http://researchrepository.napier.ac.uk/Output/8229.
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The primary aim of the project was to develop the basis for a set of rules to be used in the design of RHS slim floor edge beams with web openings. However, since the research is fundamental in nature, the findings are also applicable to other situations where it may be advantageous to cut holes in load bearing tubular members of rectangular cross-section. The study considered the influence of the number and size of holes upon resistance and stiffness in bending, shear, and torsion and combined analytical Finite Element modelling with large and small scale pseudo-static (short-time static loading) laboratory testing. In all but one category of tests (see below), good agreement was achieved between experimentally measured quantities (such as capacities, deflections and strains) and the corresponding Finite Element predictions, allowing parametric investigations to be conducted with calibrated analytical models. Preliminary design recommendations are presented based on the results of the parametric study and laboratory tests. The design advice was developed with regard to existing recommendations for the design of perforated I-beams, and was produced in a form that allows integration with modern limit state design codes. Aspects of behaviour requiring further investigation have been identified and categorised. Torsion tests on full scale RHS without web openings yielded some unexpected results. Elastic and plastic capacities measured in the laboratory were significantly lower (12–20%) than those predicted by the Finite Element models and the thick walled torsion theory used as the basis of the British and European design procedures. Attempts were made to determine the cause of this behaviour and a number of possibilities were eliminated. Although the anomalous results have not been fully explained, evidence of similar behaviour in previous full-scale testing was discovered.
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Davies, Ivor. "Moisture conditions in external timber cladding : field trials and their design implications." Thesis, Edinburgh Napier University, 2011. http://researchrepository.napier.ac.uk/Output/4702.
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This thesis describes the development of technical guidance on timber facade design. The study involved a state-of-the-art review; an exposure trial of external cladding made from Sitka spruce (Picea sitchensis) and the production of construction details and associated information. It was undertaken because timber is an increasingly common cladding material in the UK, being used on low-rise residential buildings and for medium-rise and non-domestic buildings. The risks have, therefore, increased but this is not reflected in published guidance. Sitka spruce was used due to its availability in the UK and its similarity to Norway spruce (P. abies) which is widely used for cladding in Scandinavia. The exposure trial indicated that the moisture content range in timber facades is wider than accepted. The minimum moisture content of around 10% appears to be similar for all types of timber cladding and all species. The maximum appears to vary between species according to their fibre saturation point and is influenced by construction detailing and workmanship. A preliminary model of these interactions is proposed. From a theoretical standpoint, the moisture conditions observed in the trial mean that the (commonly quoted) mean moisture content is all but irrelevant. The mode is a more representative statistic as in most cases the data are skewed towards the fibre saturation point for the species concerned. Most detailing combinations had a moisture content near to the fibre saturation point throughout the winter. Sitka spruce is, therefore, only suitable as external cladding in the UK if preservative treated. Around 40 construction details were produced. They integrate, for the first time, all of the performance requirements applicable to low- and medium-rise timber facades in the UK. The work's key benefit is that the guidance arising from this study rationalises and improves facade design. Further research is, however, needed to validate the moisture content model and extend it to other timber species.
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Su, Shenzhi. "Structure-borne sound transmission through resiliently suspended ceilings in timber frame floors." Thesis, Edinburgh Napier University, 2009. http://researchrepository.napier.ac.uk/Output/6799.
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Resilient bars provide cheap, effective sound insulation. They are increasingly popular in timber floor/ceiling assemblies in the UK following the upgrading of Building Regulations requirements. However, the behaviour mechanisms providing resilient bars with their insulating properties are not well understood. The effects of specific detailed features on their performance are assumed or estimated empirically. Myths relating to property-performance correlation prevail among various product manufacturers. Previous experimental studies revealed either overall effect or only covered the stiffness in the vertical direction. Spring and rod models used elsewhere also failed to predict three-dimensional, asymmetrical facets of resilient bar behaviour. This research investigated the influence of various three-dimensional resilient bar features through examining hypotheses: resilient bars act as springs (either vertical, bending, cantilever or spring hinge), or stiffeners. As these hypotheses are associated with certain material and geometrical features, the results revealed each's influence and relative importance. Three types of test were designed: vibration transmission, apparent stiffness and modal tests. Two representative but distinctly different resilient bar products were chosen as test subjects, which covered the features of interest and involved controversies. Vibration transmission tests were conducted on a series of configurations based on small-scale structures, which could not only demonstrate overall performance but allow detailed parametric investigations. Apparent stiffness tests on small samples enable isolation of spring effects so that their individual contribution could be evaluated. Modal tests revealed how resilient bars modified the vibration modes of the attached plate. By synthesizing the data from the above three angles together with data in the literature, the influence of key features was inferred and evaluated. Mass-spring-mass modelling and statistical energy analysis were carried oout which enhanced understanding of the system's behaviour. The findings led to an optimised resilient bar design and a patentable acoustic hanger system. The latter was prototyped and tested on a floor/ceiling assembly. The results showed that it was more advantageous than current resilient bar systems.
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Zhang, Xiaodong. "Daylighting performance of tubular solar light pipes : measurement, modelling and validation." Thesis, Edinburgh Napier University, 2002. http://researchrepository.napier.ac.uk/Output/3602.
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The innovation of natural daylighting light pipe took place more than twenty years ago. Since then its daylighting performance has been reported in a number of studies. To date, however, no mathematical method that includes the effect of straight-run and bends within light pipes has been made available. Therefore, a generalm athematicalm odel for light pipes is desirablet o assessa nd predict its daylighting performance.F urthermore,s uch a generalm odel can enablet he assessmenot f light pipe system's efficiency and potential in energy saving. A modified form of daylight factor, Daylight Penetration Factor (DPF), has been introduced to build a sophisticated model that takes account of the effect of both internal and external environmental factors, and light pipe configuration. Measurementsa nd mathematicalm odelling activities aimed at predicting the daylighting performance of light pipes with various configurations under all weather conditions in the UK were undertaken. A general daylighting performance model, namely DPF model, for light pipes was developed and validated. The model enables estimation of daylight provision of the light pipes with a high degree of accuracy, i. e. R2 values of 0.95 and 0.97 for regression between predicted and measured illuminance were respectively obtained for the above model. The DPF model uses the most routinely measured radiation data, i. e. the global illuminance as input. Considering that in real applications, light pipes installed in a particular building may not receive the full amount of global illuminance as measured by local meteorological office. This may be due to partial shading of the light pipe top collector dome. Therefore, to enable the application of the DPF model in practical exercisesf undamentalw ork on sky diffuse illuminance measurementsh ave been undertaken. An exhaustive validation has been carried out to examine the DPF model in terms of the structure of the model and its performance. The DPF model was compared against studies by other independent researchersin the field. Independentd ata setsg atheredf rom a separates ite were used to validate the performance of the DPF model. Comprehensive statistical methods have been applied during the course of validation. Relevant, brief economic and environmental impact of the technology under discussion has also been undertaken. One of the main achievementso f this work is the mathematicalm ethod developedt o evaluatet he daylighting performance of light pipes. T'he other main achievement of this work is the development and validation of the DPF models for predicting light pipes' daylighting performance.
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Abu-Shabeen, Nadine Nabeel. "Development of multi-criteria decision analysis models for bidding and contractor selection." Thesis, Edinburgh Napier University, 2008. http://researchrepository.napier.ac.uk/Output/3746.
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Estimating and bidding a job is one of those essential processes at the heart of a contractor's business. Risk and uncertainty are major considerations in bidding decisions for construction projects. Numerous factors need to be taken into account when making bidding decisions which make them multi-criteria decisions. The present study focuses on developing multi-criteria decision making models to assist in bidding decisions. The Analytical Hierarchy Process (AHP), which is a multi-criteria decision making tool, is used to quantify risk encountered in bidding decisions. The AHP has been employed to model both the bid/no bid and mark-up decisions. The data required for this study was collected from thirty firms operating in Gaza Strip by way of a written structured questionnaire. The data was analysed using the Criterium Decision Plus Software based on the AHP. Ten factors were selected to affect bid/no bid decisions while eleven factors were chosen to influence mark-up decision. Results from the questionnaire survey supported previous studies that profit is not the most important factor in making bid/no bid and mark-up decisions. The results also indicate that the most important factors when making the bid/no bid decision are: the 'need for work' followed by the 'company strength in industry' and 'payment methods'. For the mark-up decision, the 'need for work', 'owner/client and consultant identity' and 'project size' are the most important factors. A real life case study was used to demonstrate the application of the two models. Twelve meetings were conducted with a contractor working in Gaza Strip construction industry in order to gather the required data for the validation. The case study consisted of three different projects, road works, electromechanical and building projects, and the contractor had to make a decision on which projects to bid for and then which of them will result in a higher mark-up. The validity of the two models was confirmed by applying a two-stage Linear Programming (LP) approach to the data obtained from the case study. The results from the LP approach agreed with the outcome from the AHP. The developed AHP models can be easily used by the contractors to assist in making bid/no bid and mark-up decisions. This study investigates the Fuzzy Sets Theory, which is a mathematical approach used to characterise and quantify uncertainty, as a bidding strategy. This study summarises the work that has been done to-date reviewing the fundamental concepts and applications of the Fuzzy Sets Theory in construction. Fuzzy Sets Theory was found to be used widely in construction research but most studies were found theoretical. The research also examines the challenges of using the reverse auction as an open bidding process. In construction industry, reverse auction is one such technique that uses secured Internet technology for tendering process. Advantages of on-line bidding include: the ability to submit more than one bid, time benefits, increasing competitiveness among contractors and attracting unknown bidders. The main drawback of reverse auctions is that the award of the product/service will be based on the price rather than on the quality of the product or service. Furthermore, security and legal issues need further considerations when forming e-contracts for the procurement of construction services. Selecting a suitable contractor to execute a particular project is an important decision for the client to take. Awarding construction contracts based on the price only is not always a successful strategy for contractor selection as it could result in construction delays and cost overruns. In addition to price, factors such as quality and safety need to be taken into account when making the contractor selection decision. In this study, two methods for contractor selection were compared: the points method and the Analytical Hierarchy Process. The two methods were applied to a real life case study for contractor selection. Financial and Quality factors were considered to affect the contractor selection decision. Both methods resulted in selecting the same contractor for executing the project under consderation. The Analytical Hierarchy process provides a flexible and computer based method for contractor selection decision.
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Khokhar, Aamir Muhammad. "The evaluation of shear properties of timber beams using torsion test method." Thesis, Edinburgh Napier University, 2011. http://researchrepository.napier.ac.uk/Output/4406.
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Girard, Aymeric. "Modelling the energy resource for buildings and the use of appropriate low carbon technologies." Thesis, Edinburgh Napier University, 2011. http://researchrepository.napier.ac.uk/Output/6695.
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This thesis investigates the feasibility of the use of Low or Zero Carbon Energy Sources (LZCES) in the built environment and the development of an innovative Integrated Renewable Energy Planner (IREP) tool. It can be divided into four main research areas; an investigation into the on-site renewable energy resource, an analysis in the building energy usage profile, a development of a decision-making tool for the rapid identification of the most appropriate LZCES option and a post occupancy monitoring and modelling of a building. This research work details the following considerations of LZCES: passive solar space heating modelling (PSSH); performance of building integrated including solar water collector (SWH); solar photovoltaic (SPV); wind technology (WT); ground source heat pump (GSHP); tri-generation (TriG); biomass (BioH) and rainwater harvesting (RWH). Recorded Chartered Institute of Building Services Engineer (CIBSE) data from fourteen cities around the UK were used to assess the wind, solar electric, solar passive thermal, solar water thermal, ground source and rain resource. As part of this project, an unoccupied solar house was monitored for one summer and one winter month in East Whitburn, Scotland. A detailed investigation into the effect of external temperature, irradiance and thermal mass was conducted on building perFormance and indoor temperature. It was found that the estimated internal temperature simulation was between 2% to 10% different from the monitored temperature. It could be improved if the thermal mass and ventilation rate were estimated more accurately. A collection of manufacturers' data from 10 WTs, 10 SWHs, 3 SPVs, 2 GSHPs, 2 BioHs, 3 Tries and 2 RWHs was carried out in order to test the performance of the IREP tool. Energy, economy and CO2 saving simulations were done on a number of LZCES systems. A final assessment of the number of different options and their impact on the cost, energy and CO2 saving was performed in order to assess the best combination possible. Future development of the IREP tool may aim to assess more accurately the output of each technologies, develop a more user-friendly facade and integrate more technologies such as light pipes, earth duct, solar wall, concentrated solar power, energy storage, UTES, waste-to-energy plant, fuel cells and to extend potentially to recycled materials. Other weather data from rest of the world could make IREP usable for other project scales and countries.
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Reza, Humayun. "Cleaning and restoring old masonry buildings : investigations of physical and chemical characteristics of masonry stones and clay bricks during cleaning." Thesis, Edinburgh Napier University, 2014. http://researchrepository.napier.ac.uk/Output/8851.
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Historic buildings and monuments are a precious finite asset and powerful reminders for future generations of the work and way of life of earlier cultures and civilisations. The stone cleaning and restoration of historic buildings is a crucial element in keeping the good look, integrity and quality of the fine art, method of construction and architecture of previous civilisations. Stone cleaning is one of the most noticeable changes a building can be subjected to, which changes its appearance, persona and environmental context. In this study, a series of physical and chemical tests were conducted to further investigate, evaluate and improve the efficiency of building cleaning. Seven different abrasives were adopted for air abrasive cleaning, including copper slag (fine, medium and coarse), recycled glass (fine, medium and coarse) and hazelnut/almond shell (natural abrasive), on a total of eight masonry stones and clay bricks, including yellow sandstone, red sandstone, limestone, marble, granite, white clay brick, yellow clay brick and red clay brick. Physical investigations included sieve tests and impact tests on the abrasives, greyscale image analysis, thickness reduction measurements, Vickers surface hardness tests, Charpy impact tests and water absorption tests. Chemical investigations included Scanning Electron Microscope (SEM) and Energy-Dispersive X-Ray Spectroscopy (EDX) analyses. Sieve tests and impact tests confirmed that the abrasives utilised were fairly reliable, and the abrasives with high bulk densities were stronger and tougher than those with low bulk density. Greyscale digital image analysis indicated a lower greyscale value corresponded to a dirtier masonry surface. In general, the greyscale continuously increased with the increasing cleaning time and tended to be stable when the surface became fully cleaned. The cleanness was also introduced for assessing the effectiveness of the building cleaning. Similar trends could be observed. Both parameters proved to be significantly useful. For most of the samples, monotonic increase trends were observed between the greyscale and thickness reduction. The image analysis on greyscale and the thickness measurement were two useful methods for assessing the cleaning degree of a masonry stone or clay brick. Based on the analysis on all the testing data, it is possible to recommend a more suitable abrasive for each masonry stone or brick. For granite and red clay brick, medium glass produced the best performance, while for limestone, marble and red sandstone, fine glass was promising. For yellow clay brick, fine slag could be the best option, while for yellow sandstone the natural abrasive was found to be the most suitable. vi The Vickers hardness test results indicated that a larger hardness corresponded to a harder masonry surface. Also the surface hardness continuously increased with the increasing cleaning time but at a decrease rate. Most of the increasing trends of the surface hardness could be approximately expressed using parabolic relationships. Granite was found to be the hardest, and followed by marble and limestone. However, there were no big differences in the surface hardness between yellow clay brick, yellow sandstone, red sandstone and white clay brick. The impact resistances of seven masonry stones and bricks were obtained by conducting the Charpy impact resistance tests. Granite showed the highest impact resistance among all the stones and bricks and was followed by marble, limestone, clay bricks and sandstones. The stones and bricks with higher impact resistances also had higher hardness values but lower water absorptions. The water absorbing capacity of the seven masonry stones and bricks was quantitatively determined. Two types of clay bricks showed the highest water absorptions, and the water absorptions for limestone, yellow sandstone and red sandstone were also quite high. However, the water absorption of marble and granite was found to be very low. Larger water absorption corresponded to a softer stone or brick, while smaller water absorption corresponded to a harder stone or brick. The chemical investigations by using the SEM and EDX techniques showed that the chemical substances on the masonry surface varied largely for different types of stones and bricks. This study showed the way to detect such soiling using chemical analysis by monitor the changes in chemical elements and compounds during the building cleaning. Finally, comprehensive conclusions were presented, together with useful suggestions for future work.
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De, Venny Alan S. "Recycling of demolished masonry rubble." Thesis, Edinburgh Napier University, 1999. http://researchrepository.napier.ac.uk/Output/6043.
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The recycling of demolished masonry rubble as the coarse aggregate in new concrete represents an interesting possibility at a time when the cost of dumping such material is on the increase. With growing concerns over the environmental impact of aggregate extraction and the continued rise in aggregate demand in the UK, it is clear that the market is now there for recycled and secondary aggregates. The present investigation consists of experimental and theoretical studies into the effects of using recycled aggregates to produce concrete instead of virgin aggregates. The aggregates used have been recycled from construction and demolition waste. The recycled aggregates were predominately made up of crushed bricks but the aggregates did contain impurities such as timber and mortar. New bricks were crushed to form an aggregate in order to investigate the properties of brick as a material without impurities. The physical properties of the various aggregates were firstly examined and compared with granite aggregate, an aggregate proven in the production of good quality concrete. Concrete was then produced with the aggregates and all the physical and mechanical properties of the concretes were examined in some detail. The results showed that recycled masonry aggregates can be used successfully to produce· concrete of an acceptable standard. New test methods were presented in this investigation to determine brick porosity and water absorption. This involved the testing of broken brick fragments under vacuum, rather than the testing of whole brick units by 5hrs boiling or 24hrs submersion in cold water. The new test methods proved to be easy to perform and provided accurate results. A new test method for estimating the strength of bricks was presented. This involved point-loading of masonry specimens to obtain strength index values. From the pointload results, equations were presented relating the strength index values of brick fragments to the compressive strength of whole brick units. This involved the development of shape factors for different masonry specimens. The point-load test is easy to perform, presents a cheaper alternative to heavy compression machines and can be used on site to determine the suitability of recycled bricks as the aggregate in new concrete.
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MacKenzie, Roderick. "The non-destructive evaluation of Sitka spruce mechanical properties using acoustic methods." Thesis, Edinburgh Napier University, 2009. http://researchrepository.napier.ac.uk/Output/6039.
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The need for improved timber grading is key to improving Scottish forestry: the majority (80%) of the sustainable softwood population in Scotland is Sitka spruce of variable quality. Current visual assessment of strength and stiffness is inaccurate, and machine stress grading in sawmills is little better due to incorrect assumptions regarding consistency within softwood species and between trees of the same stand. The author develops and evaluates non-destructive test (NOT) methods for Scottish Sitka spruce based upon impact-e9ho testing across a range of scales from plank, to log, to standing tree. Correlations between harmonic wave propagation velocity and elastic modulus of 0.62 ::; R2 ::; 0.71 were possible in Sitka spruce under a range of conditions including: genotype progeny, variable height and radial position in stem, and variable knot content. In achieving this correlation, the research also investigated acoustic parameters such as: time of flight velocity, damping ratio, and resonant peak behaviour with regard to their influence on dynamically derived moduli of elasticity. Examination of variation in wood properties (including static elastic modulus, knot content, simulated decay, density, and grain alignment) on these acoustic parameters was conducted on semi-controlled specimens of differing homogeneities. The consequences of these results should influence the development of timber NOT tools. In addition to the development of an NOT method, the author has provided the first large-scale derivation of reference values for dynamic stiffness and other acoustic properties for 35 year old logs and beams of Sitka spruce in Scotland.
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Tait, Colin J. "The water ingress characteristics of stressed masonry." Thesis, Edinburgh Napier University, 1999. http://researchrepository.napier.ac.uk/Output/3672.
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Water ingress, usually by wind-driven rain, is the main cause of premature deterioration in masonry structures. Water acts as a transport mechanism for aggressive chemicals and can also undergo freeze/thaw cycles leading to bursting of the masonry microstructure. Factors such as the absorption rates of brick, water/cement ratio of the mortar, workmanship of the mason and poor design detail have all been identified as influencing the amount of water likely to penetrate a structure. It is also recognized that the majority of water ingress occurs at the brick unit/mortar joint interface, where interstices are present that allow access to the masonry interior. The size, extent and influence that the brick/mortar interface has in governing water ingress is likely to be controlled by both the applied stress level and bed orientation of the main mortar beds relative to the direction of loading. Very little research has investigated these parameters in detail. By using a new ingress measurement technique, the effect of the applied stress level and bed orientation was quantified. The main mortar beds of concentrically loaded masonry panels were found to deteriorate in their resistance to water ingress as they were orientated from perpendicular to parallel relative to the direction of loading. Poisson's ratio effects, which generated differential expansion between brick and mortar were believed to control water ingress at mortarjoints orthogonal to the main beds. Water ingress at these mortarjoints was also found greatly influenced by both applied stress level and bed orientation. Factors such as the applied pressure head of water impinging onto the panel, the variability of the brick type used, eccentricity of applied loads and the pre-wetting of panels were also found to have some controlling influence on the water ingress characteristics of masonry. Empirical modelling of water ingress dependent upon time, stress level, bed orientation and pressure head of water, was also undertaken. This enabled the volume of water ingress to be mathematically generated, with these models exhibiting good agreement with experimental data. Suggestions for future work include assessing the effect of higher applied stress levels on water ingress, verification of the laboratory work with on-site tests and the introduction of freeze/thaw testing on loaded panels to simulate an abrasive external environment. Numerical analysis using finite element modelling was also identified.
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Heritage, Ian. "Direct electric curing of mortar and concrete." Thesis, Edinburgh Napier University, 2001. http://researchrepository.napier.ac.uk/Output/6571.
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Direct electric curing is the method by which the hydration reactions within concrete are thermally accelerated by passing an alternating electric current through the sample. This use of electricity as a means of supplying heat to young concrete and mortar has become recognised as a more effective and energy efficient form of accelerating the curing process than traditional steam curing. The present investigation involves studying the affects of thermally accelerated curing of cementitious materials in comparison to normally non-heated curing. Prior to mixing, tests are performed on the constituents of the cementitious mixes. Results of these tests are used in the creation of mix designs for mortar and concrete samples. A range of concrete mixes are designed with and without additives and admixtures are used to make cubes, slabs and beams. From the testing results, the factors affecting the short and long term properties of electrically cured cementitious materials are investigated and heating regimes are presented to achieve specific properties of both strength and durability at specific ages. A substantial section of reinforced concrete is required to gain representative results in electrically curing reinforced concrete slabs. Compressive strength is difficult to measure due to the electrical distortion affects of inserts and the damage caused by coring so that at present, basic maturity concepts are used as a compressive strength guide which limits the validity of results obtained. This research looks at refining these concepts to include early age heating effects induced by direct electric curing. The microstructural development of concrete when subjected to accelerated curing is also considered. The affect of delay periods and maximum temperature is studied using a scanning electron microscope and the results presented.
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Delaney, Frank T. "Effectiveness of mergers and acquisitions and corporate financial performance in construction." Thesis, Edinburgh Napier University, 2003. http://researchrepository.napier.ac.uk/Output/2750.
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In practice, construction firms are in business to achieve profitability. Construction companies operate in a highly competitive business environment characterised by low profit margins and high failure rates. At times firms will seek to grow in an attempt to increase profitability. At other times, firms will be concerned with survival and avoiding failure. Often firms plagued by poor performance seek to take higher risks. This may lead especially where resources exist to increased diversification. Against this background, the research focuses on the twin areas of corporate financial performance and the effects of merger activity. Prior studies in economics and accounting provide evidence that financial statement analysis can be utilised by possible investors or strategic planners to aid in the future plans and direction of the firm or to classify economic events such as mergers or failures. The present study examines the financial performance of the UK construction industry and the Global construction industry, and investigates the financial characteristics of merging construction companies. This research examines the financial performance of UK firms in different sectors of the construction industry. This analysis involves the use of descriptive statistics, which provides a valuable aid in the visual presentation of the range of the possible outcomes. In addition a probabilistic analysis of the distribution of profitability has been undertaken. This involves the use of inferential statistics which concentrates on the role of significance testing. The profitability performance of the plant hire sector was found to exceed that of contracting and materials sector. An examination of the impact of the national environment on international competitive performance and an assessment and comparison of the performance of global construction is also provided in the study. The research also investigates the financial profile of UX failed and solvent firms. The use of statistical models and accounting ratios in an effort to predict company failure for up to five years is examined. The results for the univariate analysis indicate that failing construction firms during the 1996-2001 period have low profitability and are highly geared. The testing of previous statistical failure prediction models provide little evidence of compatibility to the construction industry. The analysis on mergers and acquisition investigates the performance of construction companies involved in the acquisition process and examines the motives behind the merger process. Analysis of the relation between measures of costs and firm size in over 100 UK construction companies indicates the usefulness of scale economies. However, the evidence suggests that beyond a certain size the cost benefits appear to become exhausted. Large companies have to re-examine scale to ensure that they are employing it to their company's greater advantage. Abnormal share returns are also examined throughout a period surrounding the announcement of both successful and unsuccessful acquisition and merger bids. The overall results indicate that mergers in the construction industry create wealth for shareholders. The evidence shows significant increases in the performance of the target firms' shareholders over a 40 day event window surrounding the announcement. The results also show that bidding firms' experience no significant abnormal returns in a short period surrounding the announcement date.
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Alsulamy, Saleh. "Developing a performance measurement framework for municipal construction projects in Saudi Arabia." Thesis, Edinburgh Napier University, 2015. http://researchrepository.napier.ac.uk/Output/8802.
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Performance measurement has the main aim of helping organizations to realize how decision-making processes can be harnessed to improve success rate in past activities and how the understanding from the current and past can lead to future improvements. Specifically, a comprehensive performance measurement practise must enhance the achievement of the key aim of the project stakeholders, the objectives of the project itself, and the needs of the users all of which should be capable of being represented in raw data to be manipulated and measured by a performance measurement tool. The performance of a project is directly related to its potential for success, and on the other hand, the CSFs of a project have a direct bearing on the project's performance. In essence, the efficiency and effectiveness measures of a project are essential yardsticks for assessing project performance and success. The stakeholders in a project have needs and expectations which the project is being conceived to satisfy, therefore, these needs and expectations must be held paramount during the conceptual design, development execution, and operation stages of a project. This is applicable to the general construction industry and in particular, in construction projects implemented by municipal organisations. However, municipal construction project have been fraught with delays, cost overruns and failure in operational performance. Hence, the overall aim of this research is to develop a framework within which municipal construction project performance can be measured in the SA at any stage of the project, and specifically to increase its effectiveness and efficiency of the project in order to improve the project's performance to the satisfaction of stakeholders. This study was implemented through the administration of a questionnaire survey based on a hypothesis that requires the identification of the challenges and obstacles that are facing the implementation of municipal construction project in SA. The collected data is based on responses from three major organisations; government, contractors and consultants that are involved in the delivery of municipal construction projects in SA. Mean and analysis of variance (ANOVA statistic) was used to manipulate the data from the questionnaire within the SPSS v.20 software environment. The resulting framework was subjected to a validation procedure which involved a structured interview process based on a focus group consisting of experts that were specially selected for the purpose establishing the extent to which the framework is practical, clear, applicable and comprehensive. Also, the focus group was used to determine the significance of the CSFs, PMs, and success (efficiency and effectiveness) measures. Overall, this study found that a total absence of performance measurement concept process permeates the management of construction projects in SA and in the municipality construction projects in particular. To close this gap, this study was embarked upon to investigate and identify the various performance measurement approaches and frameworks that are used to support the guidance of project performance toward success. Notably, this study emphasises the importance of stakeholder needs and expectation forming the bases of municipality construction projects in SA. Specifically, this study suggests that the measurement of project performance in municipality construction projects in SA should be integrated in a holistic framework containing several elements that will help to guide construction projects toward success.
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Mbiti, Titus Kivaa Peter, and tkivaap@yahoo com. "A System Dynamics Model of Construction Output in Kenya." RMIT University. Property Construction & Project Management, 2008. http://adt.lib.rmit.edu.au/adt/public/adt-VIT20081211.160910.
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This study investigates fluctuations of construction output, and growth of the output in Kenya. Fluctuation and growth of construction activity are matters of concern in construction industries of many countries in the developing as well as in the developed world. The construction industry of Kenya is therefore an exemplifying case for this phenomenon. Construction activity in Kenya fluctuates excessively and grows very slowly. This remains a big challenge to policy makers, developers, consultants and contractors in their decision-making processes. In this study, systems thinking was applied to investigate the problem of excessive fluctuations and stunted growth of construction output in Kenya. The study developed a system dynamics model to simulate the construction output problem behaviour. The historical behaviour of the construction industry was described using construction output data of a 40-year period - from 1964 to 2003. Line graphs of the historical data exhibited profiles that helped to identify the system archetypes operating in the industry. From the profiles, it was deduced that the problem of fluctuations and slow growth of construction output in Kenya is encapsulated in two system archetypes, namely: balancing process with a delay, and limits to growth. The relationship between construction output and its determinant factors from the constru ction industry's environment was investigated using time series regression, which involved autoregressive integrated moving average (ARIMA) regression and multiple regression modelling of the output. On the basis of the historical data analysis and the system archetypes identified, a system dynamics (SD) model was developed to replicate the problem of fluctuations and slow growth in the construction output. The data used to develop the system dynamics model was annual construction output in Kenya from 1964 to 2003. The model was then used: to appraise policy changes suggested by construction industry participants in Kenya, and to project construction output in Kenya from year 2004 to year 2050, in order to establish the expected future fluctuations and growth trends of the construction output. It was observed that three fundamental changes are necessary in the system structure of the construction industry of Kenya, in order to minimize fluctuations and foster growth in construction output in the country, in the long run. The changes are: setting long-term targets of annual construction output in the industry as a whole, incorporating reserve capacity in the production process, and expanding the system st ructure to capture a larger construction market. The study recommends regulation of the response of the construction industry of Kenya to changes in construction demand in the market, and expansion of the construction industry's market into the African region and beyond.
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Weir, Gillian Francis. "Life cycle assessment of multi-glazed windows." Thesis, Edinburgh Napier University, 1998. http://researchrepository.napier.ac.uk/Output/2747.
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In 1987 the World Commission on Environment and Development proposed a reduction in per capita energy consumption of 50%. Increasing demands, and initiatives of this nature, produce a need for more reliable assessment methods, measurement tools and improvement regimes. Since the late 1960's Life Cycle Assessment (LCA) has become an increasingly important tool for engineers, technologists, scientists, designers, managers and environmentalists alike. LCA enables the effects which products, processes and activities have on local, regional or global environments to be assessed, adopting a holistic, or whole life approach to design methodologies. The design of window systems has a large impact upon LCA results generated. Thermal performance properties influence energy consumption patterns throughout a lifetime of use, while appropriate use of materials, window positioning and size have a knock-on effect on lighting control functions and air conditioning demands. In developing countries, residential sectors account for between 20% and 30% of the total energy used (30% in the UK). Windows in dwellings alone account for 6% of the total UK energy consumption. This thesis addresses an ongoing need to focus on sustainable development, using LCA as an assessment tool to develop a greater understanding of the window life cycle, and to highlight improvements which are necessary to lessen its environmental impact and make the processes involved more benign. To do this successfully requires that the demands of modern day living, and the comfort conditions expected, be incorporated into design criteria, whilst ensuring that the needs of future generations are not compromised by today's activities. Along with rising demands to improve efficiency and decrease energy consumption in buildings, comes an expectation for continual improvement in building interiors. To this end, both the aural and visual haracteristics of window installations become paramount, in addition to the well researched thermal performance criteria. Much research has focused on investigating the social and physiological benefits associated with improved interior environments. The correlation between worker satisfaction and performance has been well proven. If complete physical well-being is satisfied then an individual's mental well-being is less likely to be affected by the additional stressors of environmental dissatisfaction. An optimisation model has been developed, linking the thermal, aural and visual performance of varying window designs, such that an "advanced" window system is created. Two outputs are generated from the model, which may be used to evaluate the "optimum" window design in terms of energy consumption and global environmental impact. Optimisation of energy consumption incorporates embodied energy, thermal performance and electric lighting demand, over the life cycle of a window. Global environmental impact optimisation is similar, but evaluation is based on energy generation, and greenhouse gas production. Finally, a flowchart for optimisation guides the user towards a glazing solution which offers sufficient noise attenuation, whilst minimising thermal losses and electric lighting demand. Each output provides a guide for design, leaving room for judgement, and is not intended to be followed definitively. Recommendations for improvements to manufacture systems and production of multiglazed windows are offered, based on sustainable development criteria. Future research needs, which are necessary to minimise the total environmental impact resulting from multi-glazed window production, are also discussed.
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Yu, K. W. "The economics of construction price inflation : measurement, output and productivity." Thesis, University College London (University of London), 2014. http://discovery.ucl.ac.uk/1457106/.
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This thesis evaluates the UK construction price and cost indices and their use in measuring inflation, construction output and productivity. It proposes theoretically grounded and econometrically sound models for construction demand and supply. This study reviews the compilation methods of the published tender price indices (TPIs) in the UK and finds that they have distinct advantages. However, some components (M&E trades), some procurement methods (design and build), and some sub-sectors (private commercial and housing) are disproportionally under-represented or absent from the sampling of projects that underpins the TPIs. The TPIs are found to be very likely biased upwards. The review of the construction cost indices in the UK, measures of the input prices facing contractors, finds that the measure of labour cost is based on increasingly unrepresentative national wage agreements, and appears to be biased upwards. The construction new orders series published by ONS are reviewed as a possible measure of demand and predictor of quantity of construction output, and are shown to be unfit for either purpose. Grounded on a simple demand-and-supply theoretical model, the method proposed by Haynes and Stone (1985) is applied to estimate a system of demand-and-supply equations for new construction work in the UK, which is tested against and supported by the results of the data-driven vector autoregressive model. Findings from EU-KLEMS show that the rate of productivity growth of the construction sector is lower than that of the whole economy. Applying Baumol’s two sector unbalanced growth model, econometric studies are undertaken for the UK and other European countries. Results confirm the proposition that the relative rate of growth of labour productivity of the construction sector determines the long-run relative price movement of its outputs. The positive productivity growth in UK construction industry explains the differential between its (higher) input price growth and (lower) output price growth.
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Deakin, Mark. "Sustainable urban development." Thesis, Edinburgh Napier University, 2011. http://researchrepository.napier.ac.uk/Output/4660.
Full textAbstract:
This submission for PhD by publication aims to capture, reflect upon, analyse and offer critical insights into how the use of land and exchange of property can help serve the search for sustainable urban development (SUD). This aim is subsequently met by: • hypothesising how the applicant's publications provide a representation of SUD able to get beyond the state-of-the-art and offer a conceptual framework capable of uncovering the positive role land and property can play in sustaining urban development; • reviewing the research undertaken by the applicant to define SUD and develop a framework for analysis, set of protocols and directory of assessment methods to evaluate the sustainability of urban development; • highlighting the possibility there is for the valuation methodologies and investment appraisal techniques underlying the use of land and exchange of property, to be constructive in terms of the relationship their corporate strategies and financial instruments have to the environment; • illustrating how it is possible to compute the informational basis of property management and draw upon the intelligence this offers cities to develop electronically-enhanced services underpinned by e-learning platforms, knowledge management systems and digital libraries, capable of supporting environmental improvements; • showing how the environmental improvements that surface from such developments in turn support the community-based approach to urban regeneration which underlies the UK government's socially-inclusive and participatory venture into ecological modernisation and democratic renewal; • providing examples of where the management of property by cities is intelligent, not only because the environmental improvement supporting their community-based approach to urban regeneration are socially-inclusive and participatory, but for the reason the ecological modernisation and process of democratic renewal underlying these developments meet the sustainability requirement; • reflecting on the contribution this representation of SUD as informational, intelligent, socially-inclusive, participatory, community-based, regenerative, ecological and democratic, makes to what is known and understood about the subject. Together these positive, analytical and constructive examinations of SUD augment into the informational basis of property management and surface as the corporate strategies and financial instruments of the electronically-enhanced service models needed for cities to be intelligent. In particular, the strategies, instruments and eGov(ernment) service models, cities need to be intelligent in valuing the environment and accounting for the socially-inclusive, participatory, community-based, regenerative, ecological and democratic qualities underlying their improvement programmes.
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Barnes, Lemuel Gregory III. "Voltage-source inverter output waveform compensation using adaptive intelligent control." Diss., Virginia Tech, 1994. http://hdl.handle.net/10919/39997.
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A single-layer neural network-based voltage compensation technique which generates minimum-distortion sinusoidal output voltages from a three-phase PWM inverter used for uninterruptible power supplies (UPS) is described. The proposed compensation technique is implemented in a microprocessor-based controller constructed in the stationary d-q frame where the controller sampling rate is twice the inverter switching frequency. The structure of a feed-forward artificial neural network connects network inputs and outputs through multiple linear or nonlinear
neuron models, and processes these input/output data associations in a
parallel distributed manner. Network inputs in the form of UPS load voltage commands and load current feedback are propagated forward in the network each controller sampling period generating the inverter output voltage commands, the network outputs, which are converted to three phase inverter switching Signals using the space vector PWM waveform generation process.Ph. D.
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Price, Terence Raymond. "Health and safety risks in the design and construction of magnetic shielding for magnetic resonance imaging (MRI) suites." Thesis, Edinburgh Napier University, 2012. http://researchrepository.napier.ac.uk/Output/5032.
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Once energised, and even when the equipment is not imaging, magnets used in magnetic resonance imaging will produce a static magnetic field that extends in three dimensions around the magnet. This static magnetic field is invisible; it is impossible to know that it is present or to be aware of it unless told. It is important to know the position and magnetic flux density of the static magnetic field because those persons having ferromagnetic material embedded within their bodies or their eyes (the result of a welding process for example), or fitted with electronic body implants, could suffer harm from the effects of the static magnetic field at relatively low levels. Those individuals fitted with some heart pacemakers could be affected at 0.5 mT. The published literature relating to magnetic resonance imaging is, by its nature, restricted to the medico-technical-academic press and does not systematically appear in publications destined for construction professionals. There is no published literature relating to the design of magnetic shielding for MRI suites as it relates to health and safety risks to those exposed to the static magnetic field during the construction, maintenance and demolition phases of a magnetic resonance imaging project. This thesis is progressive in its structure and fills gaps in knowledge by commencing with a study to determine if the requirements placed on duty holders as defined by The Construction (Design and Management) Regulations 2007 (CDM) and its antecedent regulations are understood by all those parties involved with the conception, design, construction and maintenance of an MRI suite. Several misconceptions are highlighted. A second study gave an evaluation of the availability of as-built drawings showing the position of the 0.5 mT footprint of the static magnetic field of the magnet and gives disappointing results. The third study was to assess the effectiveness of a retrofit installation of passive magnetic shielding and highlights some failings, with the fourth study to investigate if magnetic shielding had been installed to an operational MRI suite. The fifth study was to review if the client had considered the magnetic shielding design requirements of a magnet before it was installed. Finally, the sixth case study was to evaluate if there was a clear understanding by designers of the function and attributes of RF shielding and of passive magnetic shielding to a Faraday cage. Examples, by the inclusion of annotated drawings, are given. There was not a clear understanding by CDM duty-holders of responsibilities placed upon them under the CDM Regulations. The introduction of magnetic shielding into a magnetic resonance suite design can distort the symmetry of the 0.5 mT footprint of the static magnetic field, create areas of increased magnetic flux density and push parts of the 0.5 mT footprint to the outside of any designated controlled area. This will consequentially increase the risk of unscreened persons (both inside and outside the control of the employer) being exposed to the effects of the static magnetic field unless the magnitude and position of the 0.5 mT footprint is documented and disseminated to all those persons likely to come into contact with it. The incorporation of magnetic shielding as retrofit can result in leakages of magnetic flux at its joint with the finished floor and through any shielding fixing bolts. This thesis could be useful to designers in developing risk management plans for MRI suite construction, maintenance and demolition. By making a synthesis that has not been made before, this thesis makes a contribution to knowledge by addressing these issues for the first time.
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Guo, Qiu Ling. "Development of risk analysis models for decision-making in project management." Thesis, Edinburgh Napier University, 2001. http://researchrepository.napier.ac.uk/Output/2745.
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Risks and uncertainties are inherent in construction projects and if neglected these risks often lead to project cost and time overruns. Traditional methods of forecasting risks rely upon intuition and 'feel' which has proved inadequate for the needs of investors in modern construction projects. To cope with these recognised risks, a risk management framework, which consists four components (risk identification, risk classification, risk analysis and risk response), has been developed. The present research focuses on financial risks in construction management, and in particular, the development of enhanced quantitative, probabilistic methods for risk analysis. A comprehensive review of the treatment of risk and uncertainty in the construction industry is undertaken. Background knowledge of probability theory and Monte Carlo simulation is reviewed, as is previous investigations into construction network analysis and project economics. A comparison of the Programme Evaluation and Review Technique (PERT) and the Monte Carlo Simulation (MCS) methods in construction networks risk analysis is carried out. Two example projects are analysed by both methods. When applying the MCS method, a sensitivity analysis is carried out by investigating the effect of different probability distributions (Normal, Log-Normal, Beta, Triangular and Uniform) for individual activity durations, the number of simulations used and the effect of the manner of how the mean and standard deviations are set for the different probability distributions. A new analytical method, the Modified Stochastic Assignment Model (MSAM), is proposed for the prediction of project duration. Five example projects are used to demonstrate the validity of the MSAM and to illustrate its application in construction project evaluations. The accuracy of the MSAM method is assessed by comparison to the MCS method. A comparison of the MSAM with other analytical methods commonly used in construction network analysis, such as PERT and the Probabilistic Network Evaluation Technique (PNET), is also presented. The First Order Second Moment (FOSM) method, a methodology previously used solely in system reliability analysis is applied to project economics. The definition of the FOSM method is given and detailed mathematical treatments of these methods are described. The methodology of using the FOSM in construction economics is explained and ten examples are analysed using both the FOSM method and the MCS to show the applicability and the degree of accuracy of these methods. The current research shows that the MSAM method yields the probability of project completion within a prescribed target time, or the required project time at a specific probability. The research also shows that it is possible to use the FOSM methods for risk analysis in decision-making in construction economics in such areas as selection of project, elemental cost analysis, cash flow streams and setting of plant hire rates. Both methods require computational time that is significantly less than an equivalent MCS.
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Porteous, Alexander. "The structural behaviour of timber joints made with fully overlapping nails." Thesis, Edinburgh Napier University, 2003. http://researchrepository.napier.ac.uk/Output/2787.
Full textAbstract:
An integrated programme of experimental and analytical work was carried out to evaluate the nonlinear semi-rigid characteristics of timber connections using fully overlapping nails subjected to short duration lateral loading and moment. The investigation is part of a continuing programme of research at Napier University into the behaviour of timberjoints using fully overlapping nails as the connecting Z -1 mechanism. The effects of the factors and material properties that influence the behaviour of nailed joints were addressed in a structured and controlled way allowing semi-empirical models to be developed for the lateral load behaviour of rnulti-nailed timber joints using steel and plywood gusset plates. A quality control procedure was established for the testing programme and consistent standards were applied to the preparation and testing work. The semi-empirical models that were developed included for the effect of timber density: crussept late material effect- nail strength; number of nails: nail diameter; row spacing and the effect of the moisture content in the timber. They covered joints assembled with and without a gap between the timber and the gusset plates and for joints assembled with steel gusset plates, the effect of the predrill size used in the gusset plate was also investigated. The model results compared very well with the results from tests, accurately predicting the non-linear behaviour of the joints up to failure. An extensive analytical and experimental study was carried out to investigate the moment-rotation behaviour of these types ofjoints. Two linear arýd four non-linear models were developed for each type of joint and the efficiencies of the models were compared to detennine the one that best simulated the joint behaviour. The linear models consistently underestimated the capacity of the joint, giving conservative results. The best solutions were obtained by applying the torsion formula used for steel connections and incorporating the nail behaviour models developed for the non-linear lateral load joints. Account was taken of the non-linear behaviour of the connection and alternative models using fixed and moveable centres of rotation were developed. Very good comparisons were achieved between these models and the test results. A detailed comparison was made between the behaviour of the joints using the lateral load displacement models and Eurocode 5 (EC5) and it was concluded that EC5 rules did not accurately simulate the behaviour of this type of joint. It was concluded that the nail spacing rules in the code did not apply to fully overlapping nails. A limit state design method based on the principles used in EC5 has been developed from the models for the design of joints using fully overlapping nails and subjected to lateral loading or moment. The semi-rigid behaviour of the joints was also investigated and it was concluded that to safely predict the response of structures assembled with fully, overlapping nails. the semi-rigid behaviour must be included for in the analysis procedure. Rigidity factors, end fixing moment reduction factors and the secant rotational stiffness coefficients for the joints were derived. It was also shown that where the analysis was limited to the serviceability limit state. a modified elastic method of analysis could be used and where it was beyond this state a non-linear method of analysis was required.
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Garnier, Celine. "Performance measurement and mathematical modelling of integrated solar water heaters." Thesis, Edinburgh Napier University, 2009. http://researchrepository.napier.ac.uk/Output/2593.
Full textAbstract:
In a period of rapidly growing deployment of sustainable energy sources the exploitation of solar energy systems is imperative. Colder climates like those experienced in Scotland show a good potential in addressing the thermal energy requirement of buildings; particularly for hot water derived from solar energy. The result of many years of global research on solar water heating systems has outlined the promising approach of integrated collector storage solar water heaters (ICS-SWH) in cold climates. This calls for a need to estimate the potential of ICS-SWH for the Scottish climate. This research project aims to study and analyse the performance of a newly developed ICS-SWH for Scottish weather conditions, optimise its performance, model its laboratory and field performance together with its environmental impacts and analyse its integration into buildings and benefits of such a heating system, for the primary purpose of proposing a feasible ICS-SWH prototype. Laboratory and field experiments were performed to investigate the performance of the newly developed ICS-SWH and the parameters affecting it which were fundamental to modelling its performance. This was followed by developing a thermal macro-model able to compare the temperature variation in different ICS-SWH designs; including internal temperature and external weather conditions for a given aspect ratio and to evaluate the performance of this ICS-SWH for laboratory and field conditions. This was followed by a three-dimensional Computational Fluid Dynamic (CFD) analysis of the ICS-SWH in order to optimise the fin spacing as a means of improving its performance. A Life Cycle Assessment (LCA) and monetary analysis considering the whole life energy of the different ICS-SWH designs were carried out using a previously developed thermal model in order to establish the most viable ICS-SWH with the smallest carbon footprint. Finally, a study to show how the ICS-SWH could be integrated into buildings and its potential benefits to builders and households was undertaken. Through this work, important parameters for modelling laboratory and field performance of ICS-SWH are established. The innovative modelling tool developed can predict the bulk water temperature of the ICS-SWH for any orientation and location in the world with good accuracy. Improvements of the ICS-SWH fin design were suggested through the CFD analysis while keeping the costs to a minimum. The ICS-SWH prototype showed a high commercial potential due to its environmental and monetary benefits as well as its potential for integration into commonly used solar water heating installations and modern methods of construction such as roof panels which could result in a viable commercialisation of the prototype.
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Asif, Muhammad. "Life cycle assessment of aluminium-clad timber windows." Thesis, Edinburgh Napier University, 2002. http://researchrepository.napier.ac.uk/Output/2505.
Full textAbstract:
Over the last century a temperature rise of 0.6 C m global climate and the affiliated greenhouse effects have inflicted enormous impacts in the form of natural catastrophes, economical losses, health problems and seasonal disorder. If human activities continue at existing pace, a further temperature rise of 2.5 C is being anticipated over the next hundred years, which may cause unimaginable damage to humanity and ecology of the planet. In such a prevailing global environmental scenario sustainability is the need of hour and should be given the prime importance in execution of activities in all sectors in order to keep future secure for coming generations. Windows are amongst the most sensitive elements in a building envelope, also, due to their multi-disciplinary role, they are important not only for their effects on interior environment but also for the energy performance of the building. Energy contents and environmental impacts of the materials involved, add up on to window significance in the ecology of buildings. Energy efficient windows with least possible environmental burden over their whole life cycle are thus very important in achieving desired levels of sustainability in general, particularly in buildings. The present work addresses the sustainability of double glazed aluminium clad timber windows adopting the life cycle assessment (LCA) approach. LCA of windows helps cutting down the associated ecological burdens at all stages, i.e. extraction/production of materials, operation, maintenance and disposal of windows at the end of their service life. Cost effectiveness and productivity, the important features of sustainability, have been evaluated for aluminium clad timber and timber windows on the basis of life cycle cost assessment (LCCA) approach. Value engineering (VE) of aluminium clad timber windows has also been addressed. Running and/or maintenance costs which largely determine the life cycle costing have been estimated and the most cost effective options are presented. Four different types of windows, made of aluminium, aluminium clad timber, PVC and timber frame, have also been compared with respect to the ecology of frame materials - covering energy contents and environmental loads, maintenance and durability, service life and costing. A survey has been carried out with the help of housing authorities, architects and surveyors within UK, to study the performance of these windows in real life. A series of accelerated tests have been carried out to study the weathering performance of the candidate windows. The results have revealed that aluminium clad timber windows have excellent resistance against weathering conditions and they perform better than aluminium, PVC and timber windows under any conditions. In an ongoing research project at Napier, copper (Cu) coated silicon carbide (SiC) reinforcement particles have been used in aluminium 6061 matrix to enhance the mechanical properties of the Al SiC metal matrix composite (MMC), which is a prospective material to be used in window hardware. Results have indicated that Cu coating does not bring any additional corrosion loads onto the MMC. Recommendations for further work have also been laid out.
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Tanratanawong, Sirichai. "A neural network model to forecast construction output in the United Kingdom." Thesis, University of Newcastle Upon Tyne, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.341440.
Full text
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Bruckner, Martin, Richard Wood, Daniel Moran, Nikolas Kuschnig, Hanspeter Wieland, Victor Maus, and Jan Börner. "FABIO - The Construction of the Food and Agriculture Biomass Input-Output Model." WU Vienna University of Economics and Business, 2019. http://epub.wu.ac.at/6991/1/WP_27.pdf.
Full textAbstract:
Primary crops are linked to final consumption by networks of processes and actors that convert and distribute food and non-food goods. Achieving a sustainable metabolism of this bio-economy is an overarching challenge which manifests itself in a number of the UN Sustainable Development Goals. Modelling the physical dimensions of biomass conversion and distribution networks is essential to understanding the characteristics, drivers and dynamics of our societies' biomass metabolism. In this paper, we present the Food and Agriculture Biomass Input-Output model (FABIO), a set of multi-regional supply, use and input-output tables in physical units, that document the complex flows of agricultural and food products in the global economy. The model assembles FAOSTAT statistics reporting crop production, trade, and utilisation in physical units, supplemented by data on technical and metabolic conversion efficiencies, into a consistent, balanced, input-output framework. FABIO covers 191 countries and 130 agriculture, food and forestry products from 1986 to 2013. The physical supply-use tables offered by FABIO provide a comprehensive, transparent and flexible structure for organising data representing flows of materials within metabolic networks.
They allow tracing biomass flows and embodied environmental pressures along global supply chains at an unprecedented level of product and country detail and can help to answer a range of questions regarding environment, agriculture, and trade.Series: Ecological Economic Papers
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Amigo, Jesus Menendez. "Optimisation of timber frame closed panel systems for low energy buildings." Thesis, Edinburgh Napier University, 2017. http://researchrepository.napier.ac.uk/Output/1035263.
Full textAbstract:
The United Kingdom published a legally binding document to reduce national greenhouse gas emissions by year 2020 up to 34% against the 1990 levels. This target also fulfils the Europe 2020 strategy of 20% carbon emission reductions by year 2020 (EC, 2010). Emissions due to space heating count for around 60% of the total domestic emissions (DCLG, 2012). The report “Rethinking Construction” published in 1998 emphasised the opportunities to improve the quality and efficiency of the UK construction sector (Egan, 1998). More recently, a framework has been published by the Government to tackle fuel poverty by building more energy efficient homes (DECC, 2015). In terms of energy performance, Passivhaus is recognised as one of the most energy efficient and researched construction standards which requires an exceptionally high-level of insulation and airtightness. Closed-panel timber frames are a relatively new system in UK with an opportunity for growth. These advanced panels are pre-fitted in the factory, reducing the on-site work. However, closed-panel systems present a more complex sole plate fixing detail which can have an undesirable long-term impact on the structural and thermal performance of the building. The work presented in this thesis investigates the structural considerations, racking performance, of timber frame closed panel systems for future building regulations. The thesis underlines the significance of structural stability, serviceability and detailing in relationship with long-term thermal efficiency and airtightness, according to Passivhaus standard. An experimental study was carried out to investigate the structural racking performance of advanced closed panel systems. A comparison was made between the behaviour of the timber frame panels and the analytical PD 6693-1. A set of different wall panel built-ups is presented for optimised Passivhaus design, including thermal bridge-free sole plate details. A timber frame racking software application was developed to optimise the structural design of shear walls. A parametric study was carried out with this tool to generate efficient timber frame wall design tables for different applied racking loads and U-values. The software application also allows for direct specification of robust sole plate base fixings and thermal bridge free details.
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Brand, Steven James. "A reassessment of the hybrid approach to the construction of regional input-output tables." Thesis, University of Plymouth, 1998. http://hdl.handle.net/10026.1/2155.
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This thesis lays the foundation for the creation of an economic database for the counties of Devon and Cornwall in the form of a regional input-output table. The thesis reconsiders the popular hybrid approach to the construction of such tables. In particular, the nonsurvey-to-survey ordering of procedure is questioned. The thesis attempts to restore a more logical preference-order which begins with first-best (survey) estimation methods and extends to second-best (survey-based-nonsurvey) methods. The third-best methods of estimation (pure nonsurvey i.e. location quotient) are excluded from the process altogether. The thesis is largely concerned with the development of the second-best method. The second-best method is derived from an empirical analysis of the nature of nonsurvey estimation error. The analysis is able to reject the Stevens et al. (1983) hypothesis that differences in regional and national production functions are insignificant. Nevertheless, the strategy of developing 'trade-only' nonsurvey estimation methods is found to be valid since, whilst the error associated with regional trade misspecification can be reduced within a broad method of estimation, the error attributable to the misspecification of regional production functions remains largely intractable to such an approach. Survey resources must therefore be devoted to the specification of these functions. The second-best methodology extends the Stevens et al. (1983) by deriving equations that specify the RAS algorithm and local expenditure propensities for households from empirical data for Scotland. These equations have general application within the new hybrid methodology. By restoring a more logical preference-order of approach to estimating hybrid regional input-output tables, emphasis is placed on the analytical strength afforded by a good data set, and not on the analytical 'strength' of magic-box mathematics. This should encourage the regional input-output table to be implemented as an evolving local economic database, which will improve the general quality of regional analysis and, in the long-run, offer cost-savings in data collection and collation.
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Chen, Jing. "Analysis and design of multiple-output forward converter with weighted voltage control." Diss., Virginia Tech, 1994. http://hdl.handle.net/10919/39565.
Full textAbstract:
This work presents the modeling and analyses of multiple-output forward converters with weighted voltage control. Based upon the analyses, the systematic design methodologies and design tools are provided.
A power stage de model including all the major parasitics, which are detrimental to the output voltages, is detived. A nonlinear programming based design tool is developed to search for the weighting factors. Five methods of stacking secondaries to improve cross-regulation are presented, and the improvement of cross-regulation is quantified.
A small-signal model of the multiple-output converters with coupled output filter inductors and weighted voltage control is established. The small-signal characteristics are studied, and the model shows that the system behavior is very sensitive to the coupling coefficient, which has been reported, but never been quantified. The pole-zero interlaced condition is derived. A current-mode control small-signal model is also presented, which can predict all the observed phenomena of current-mode control. Compensator design is
discussed for different types of power stage transfer functions for both voltage-mode and
current-mode control.Ph. D.
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Gallardo, Angelo Miguel Asuncion. "Design and Construction of 1800W Modular Multiple Input Single Output Non-Isolated DC-DC Converters." DigitalCommons@CalPoly, 2017. https://digitalcommons.calpoly.edu/theses/1739.
Full textAbstract:
This thesis report details the design and construction of non-isolated DC-DC converters to create a Multiple Input Single Output (MISO) converter for combining multiple renewable energy sources into one single output. This MISO uses the four-switch buck-boost topology to output a single 48V from multiple nominal 24V inputs. The MISO converter implements a modular approach to deliver 1800W output power. Each module in the MISO is rated at 600W and they share the output power equally. Hardware results show that the converter produces 1800W of output power from three sources with 96.4% efficiency. Each module also demonstrates equal sharing feature of the MISO converter.
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Gray, Terrence Patrick 1954. "A parallel adapter for a high-speed serial bus." Thesis, The University of Arizona, 1989. http://hdl.handle.net/10150/277032.
Full textAbstract:
This paper describes the building of a parallel converter for a high-speed serial bus. The high-speed serial port of the Macintosh personal computer is used to implement the bus, while an MC68000 Educational Computer Board is used to perform the serial-to-parallel conversion. The device's performance is evaluated, and possible methods for improving its performance are discussed.
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Phillips, Grant. "Design and development of a remote reconfigurable internet embedded I/O controller." Thesis, Port Elizabeth Technikon, 2003. http://hdl.handle.net/10948/116.
Full textAbstract:
The use of embedded Internet systems is growing rapidly in the manufacturing sector. These systems allow the monitoring and controlling of plant machinery and manufactured items from a remote location via a standard Web interface. In a manufacturing environment, it is inevitable that long running processes will require support for dynamic reconfiguration because, for example, machines may fail, services may be moved or withdrawn and user requirements may change. In such an environment it is essential that the operation and architecture of such processes can be modified to reflect such changes. This research project will present methods and ideas for establishing a reconfigurable remote system by using standard 8-bit microcontrollers and reconfigurable hardware. It will allow a manufacturing process to be modified and changed within minutes without even having to be physically present at the location where the process is running.
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Mendoza, Fabian, and Andreas Varli. "Hur stress påverkar byggproduktionen och dess ekonomiska konsekvenser." Thesis, KTH, Byggvetenskap, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-174849.
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Stress is a growing problem in Sweden where it has become increasingly more common and tangible, not least in the construction industry where stress affects both employees and companies negatively. The employees’ health decreases and they suffers from several ailments and long term illnesses which costs companies a huge amounts of money every year. The aim with this report is to investigate and also to get an insight into the factors that causes the perceived stress among the employees at NCC Construction Stockholm. The purpose is additionally to show how stress can affect the building process. The report also investigates the differences among the construction managers and the professional workers regarding perceived stress as well as the costs of the long term illnesses causes by stress for each professional group. This will be determined using: Interviews Surveys Previous research regarding the subject Statistics The objective of this report is to: Come up with different proposals to reduce and prevent stress in the construction industry Calculate the costs of the long term illnesses that are causes by stress at NCC Calculate how much NCC can save if the absenteeism causes by stress decreases The result from the study shows that there are differences between both professional groups regarding stress, which also reflects on the costs of the long term illnesses. The problem with stress at NCC depends on the same factors as the rest of the construction industry that is, short construction periods, insufficient construction documents and a high workload. The study also shows that the employees who are older and more experienced are not bothered as much by the stress, and that they generally handle stress better than the younger age groups do. In conclusion it can be established that stress does not always have a negative effect, but also have a positive impact on the human way to performStress är ett växande problem i hela Sverige där den blir alltmer vanlig och påtaglig. Inte minst gäller detta i byggbranschen, där stressen både påverkar de anställda och företagen negativt. Arbetstagarna mår sämre, drabbas av flera åkommor och långtidssjukskrivningar som kostar företagen stora summor pengar varje år. Syftet med rapporten är att utreda och få en inblick i vilka faktorer som orsakar den upplevda stressen hos de anställda på NCC Construction, Stockholm och hur den påverkar byggproduktionen. Det utreds även skillnader hos tjänstemän och yrkesarbetare gällande upplevd stress samt sjukskrivningskostnaderna som beror på stress för respektive yrkesgrupp. Detta kommer fastställas med hjälp av: Intervjuer Enkäter Tidigare forskning inom ämnet Statistik Målet med denna rapport är att: Komma fram till olika förslag och åtgärder för att minska och förebygga stressen i byggbranschen. Beräkna sjukskrivningskostnaderna som beror av stress hos NCC. Beräkna hur mycket NCC kan spara om sjukfrånvaron som beror av stress minskar. Resultatet från studien visar att det finns skillnader mellan de olika yrkesgrupperna angående upplevd stress, vilket även avspeglas på sjukskrivningskostnaderna som beror på stress. Problemen med stress på NCC beror på samma faktorer som resten av byggbranschen det vill säga, korta byggtider, dålig planering och hög arbetsbörda. Studien visar också på att de äldre och erfarna i branschen inte besväras lika mycket av de negativa stressfaktorerna samt att de överlag hanterar stressen på ett bättre sätt än vad de yngre åldersgrupperna gör. Mot denna bakgrund kan det avslutningsvis fastställas att stress inte behöver innebära något negativt, utan också kan ha en positiv inverkan för människans sätt att prestera.
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Baker, Bryant. "A 3.6 GHz Doherty Power Amplifier with a 40 dBm Saturated Output Power using GaN on SiC HEMT Devices." PDXScholar, 2014. https://pdxscholar.library.pdx.edu/open_access_etds/1781.
Full textAbstract:
This manuscript describes the design, development, and implementation of a linear high efficiency power amplifier. The symmetrical Doherty power amplifier utilizes TriQuint's 2nd Generation Gallium Nitride (GaN) on Silicon Carbide (SiC) High Electron Mobility Transistor (HEMT) devices (T1G6001032-SM) for a specified design frequency of 3.6 GHz and saturated output power of 40 dBm. Advanced Design Systems (ADS) simulation software, in conjunction with Modelithic's active and passive device models, were used during the design process and will be evaluated against the final measured results. The use of these device models demonstrate a successful first-pass design, putting less dependence on classical load pull analysis, thereby decreasing the design-cycle time.
The Doherty power amplifier is a load modulated amplifier containing two individual amplifiers and a combiner network which provides an impedance inversion on the path between the two amplifiers. The carrier amplifier is biased for Class-AB operation and works as a conventional linear amplifier. The second amplifier is biased for Class-C operation, and acts as the peaking amplifier that turns on after a certain instantaneous power has been reached. When this power transition is met the carrier amplifier's drain voltage is already approaching saturation. If the input power is further increased, the peaking amplifier modulates the load seen by the carrier amplifier, such that the output power can increase while maintaining a constant drain voltage on the carrier amplifier.
The Doherty power amplifier can improve the efficiency of a power amplifier when the input power is backed-off, making this architecture particularly attractive for high peak-to-average ratio (PAR) environments. The design presented in this manuscript is tuned to achieve maximum linearity at the compromise of the 6dB back-off efficiency in order to maintain a carrier-to- intermodulation ratio greater than 30 dB under a two-tone intermodulation distortion test with 5 MHz tone spacing. Other key figures of merit (FOM) used to evaluate the performance of this design include the power added efficiency (PAE), transducer power gain, scattering parameters, and stability. The final design is tested with a 20 MHz LTE waveform without digital pre-distortion (DPD) to evaluate its linearity reported by its adjacent channel leakage ratio (ACLR).
The dielectric substrate selected for this design is 15 mil Taconic RF35A2 and was selected based on its low losses and performance at microwave frequencies. The dielectric substrate and printed circuit board (PCB) design were also modeled using ADS simulation software, to accurately predict the performance of the Doherty power amplifier. The PCB layout was designed so that it can be mounted to an existing 4" x 4" aluminum heat sink to dissipate the heat generated by the transistors while the part is being driven. The performance of the 3.6 GHz symmetrical Doherty power amplifier was measured in the lab and reported a maximum PAE of 55.1%, and a PAE of 48.5% with the input power backed-off by 6dB. These measured results closely match those reported by design simulations and demonstrate the models' effectiveness for creating a first-pass functional design.
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Janse, van Rensburg HP. "Development of a digitising workstation for the electronics laboratory utilising the personal computer." Thesis, Cape Technikon, 1994. http://hdl.handle.net/20.500.11838/1081.
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Thesis (Masters Diploma (Electrical Engineering)--Cape Technikon, Cape Town,1994This thesis describes the design, development and implementation of a digitising workstation for the electronics laboratory that utilises the personal computer.
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Her, Shyang-Kuen. "Improved I/O pad positions assignment algorithm for sea-of-gates placement." PDXScholar, 1992. https://pdxscholar.library.pdx.edu/open_access_etds/4316.
Full textAbstract:
A new heuristic method to improve the I/O pad assignment for the sea-of-gates placement algorithm "PROUD" is proposed. In PROUD, the preplaced I/O pads are used as the boundary conditions in solving sparse linear equations to obtain the optimal module placement. Due to the total wire length determined by the module positions is the strong function of the preplaced I/O pad positions, the optimization of the I/O pad circular order and their assignment to the physical locations on the chip are attempted in the thesis. The proposed I/O pad assignment program is used as a predecessor of PROUD. The results have revealed excellent improvement.
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Schaeffer, Ben. "Synthesis of Linear Reversible Circuits and EXOR-AND-based Circuits for Incompletely Specified Multi-Output Functions." PDXScholar, 2017. https://pdxscholar.library.pdx.edu/open_access_etds/3783.
Full textAbstract:
At this time the synthesis of reversible circuits for quantum computing is an active area of research. In the most restrictive quantum computing models there are no ancilla lines and the quantum cost, or latency, of performing a reversible form of the AND gate, or Toffoli gate, increases exponentially with the number of input variables. In contrast, the quantum cost of performing any combination of reversible EXOR gates, or CNOT gates, on n input variables requires at most O(n2/log2n) gates. It was under these conditions that EXOR-AND-EXOR, or EPOE, synthesis was developed.
In this work, the GF(2) logic theory used in EPOE is expanded and the concept of an EXOR-AND product transform is introduced. Because of the generality of this logic theory, it is adapted to EXOR-AND-OR, or SPOE, synthesis. Three heuristic spectral logic synthesis algorithms are introduced, implemented in a program called XAX, and compared with previous work in classical logic circuits of up to 26 inputs. Three linear reversible circuit methods are also introduced and compared with previous work in linear reversible logic circuits of up to 100 inputs.
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Becker, Jane A. "Optimizing the touch tablet: the effects of lead-lag compensation and tablet size." Thesis, Virginia Polytechnic Institute and State University, 1986. http://hdl.handle.net/10919/94450.
Full textAbstract:
A major design aspect of touch tablet operation is the display/control (D/C) gain. The primary objective of this research was the development and optimization of a variable D/C gain to improve human performance with touch tablets. This variable gain minimizes the speed-accuracy trade-off problem associated with traditional D/C gains. An additional objective.of this research was to determine the effect of tablet size on human performance.
Display/control (D/C) gain is defined as the amount of movement which occurs on the display in response to a unit amount of movement of the control. With traditional D/C gains, there is a trade-off between low D/C gain which enables fine positioning, but results in very slow cursor movement, and high D/C gain which produces quick cursor movement but results in poor fine positioning ability. A lead-lag compensator which ameliorates this trade-off problem was developed. A lead-lag compensator is composed of a pure position gain component plus an additional velocity gain component.
The results indicate that a lead-lag compensator greatly increased the target acquisition rate relative to a traditional D/C gain system.
Percentage error increased with lead-lag compensation relative to an uncompensated system. The overall error rates were very low in all cases, however.
Tablet size did not appear to significantly affect performance; performance on the three tablet sizes was generally consistent.M.S.
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Hao, Kecheng. "Equivalence Checking for High-Assurance Behavioral Synthesis." PDXScholar, 2013. https://pdxscholar.library.pdx.edu/open_access_etds/1066.
Full textAbstract:
The rapidly increasing complexities of hardware designs are forcing design methodologies and tools to move to the Electronic System Level (ESL), a higher abstraction level with better productivity than the state-of-the-art Register Transfer Level (RTL). Behavioral synthesis, which automatically synthesizes ESL behavioral specifications to RTL implementations, plays a central role in this transition. However, since behavioral synthesis is a complex and error-prone translation process, the lack of designers' confidence in its correctness becomes a major barrier to its wide adoption. Therefore, techniques for establishing equivalence between an ESL specification and its synthesized RTL implementation are critical to bring behavioral synthesis into practice.
The major research challenge to equivalence checking for behavioral synthesis is the significant semantic gap between ESL and RTL. The semantics of ESL involve untimed, sequential execution; however, the semantics of RTL involve timed, concurrent execution. We propose a sequential equivalence checking (SEC) framework for certifying a behavioral synthesis flow, which exploits information on successive intermediate design representations produced by the synthesis flow to bridge the semantic gap. In particular, the intermediate design representation after scheduling and pipelining transformations permits effective correspondence of internal operations between this design representation and the synthesized RTL implementation, enabling scalable, compositional equivalence checking. Certifications of loop and function pipelining transformations are possible by a combination of theorem proving and SEC through exploiting pipeline generation information from the synthesis flow (e.g., the iteration interval of a generated pipeline). The complexity brought by bubbles in function pipelines is creatively reduced by symbolically encoding all possible bubble insertions in one pipelined design representation. The result of this dissertation is a robust, practical, and scalable framework for certifying RTL designs synthesized from ESL specifications. We have validated the robustness, practicality, and scalability of our approach on industrial-scale ESL designs that result in tens of thousands of lines of RTL implementations.
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Cooper-Searle, Simone. "Industry and policy implementation of material efficiency." Thesis, University of Cambridge, 2018. https://www.repository.cam.ac.uk/handle/1810/273169.
Full textAbstract:
The UK has committed to deep, long-term reductions in national greenhouse gas emissions as part of a global effort to address climate change. Material efficiency, reducing the material inputs per service output, has long been identified as a globally underexplored mitigation strategy. Previous studies show unrealised technical potential to improve the efficiency of steel use, a large contributor of industry emissions, in the UK. This thesis explores why these opportunities may be unrealised along the steel supply chain.
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Kratina, Zdeněk. "Zhodnocení účinnosti managementu BOZP ve stavebnictví v ČR." Master's thesis, Vysoké učení technické v Brně. Ústav soudního inženýrství, 2015. http://www.nusl.cz/ntk/nusl-233192.
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Thesis deals with the development of risk management in the construction industry in Czech republic in time of the economic crisis since 2007. There is in detail described the present and paste state of the construction industry in this thesis, thanks to construction output index, the volume of construction output, etc. There is overview of accidents and deaths in costuction industry, history of risk management in the construction industry and the main reasones of injuries and deaths in the construction industry described in this thesis. The aim of this thesis is to inform about development and efectiveness of risk management and evaluate work injuries in construction industry with the assumption further development.
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Svärdsten, Nymans Fredrik. "Constituting performance : Case studies of performance auditing and performance reporting." Doctoral thesis, Stockholms universitet, Företagsekonomiska institutionen, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-83435.
Full textAbstract:
The aim of this thesis is to problematize how and under what conditions organizational performance is constituted in the practices of performance auditing and accounting. Organizational performance disclosure is a world-wide phenomenon for enabling accountability relationships in large organizations regardless of the societal sector they operate in. In constitutive accounting literature, there is a well-established notion that accounting and performance auditing enable “government at a distance” by representing organizational actions and results of those actions, i.e. by constituting performance. Accounting and performance auditing have been regarded as “technologies of government” that make government from spatial and temporal distances possible by linking political and programmatic ambitions, i.e., the will of a superior, to everyday organizational conduct. However, whereas many previous studies of accounting and performance auditing as technologies of government focus on the discourses over the technologies of accounting and performance auditing, this thesis focuses its analysis on the operationalization of these technologies in local organizational settings. By studying the constitution of performance in the practices of accounting and performance auditing this thesis contributes by problematizing that which supposedly makes government at a distance possible. The thesis is based on two case studies of performance audit and two case studies of performance reporting. On the basis of these papers, the thesis studies the constitution of performance in performance auditing and accounting. Whereas the constitution of performance may seem stable and unproblematic at the level of discourse, this thesis suggests that constituting performance is a complex process of social construction that requires significant organizational efforts and that the ability of accounting and performance auditing to connect political and programmatic ambitions to daily organizational conduct cannot be taken for granted. The thesis suggest that once we acknowledge that performance is a socially constructed representation of organizational actions and begin to pay attention to how performance is constituted in local organizational settings, we can find new ways of addressing the ongoing challenge of constituting performance in accounting and performance auditing and increase our understanding about the ability of these practices to enable government at a distance.At the time of doctoral defence the following papers were unoublished and had a status as follows: Paper nr. 2: Manuscript; Paper nr. 3: Manuscript; Paper nr. 4: Manuscript