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Huang, Jun, and 黃俊. "Efficiency enhancement for nanoelectronic transport simulations." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2013. http://hdl.handle.net/10722/196031.
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Continual technology innovations make it possible to fabricate electronic devices on the order of 10nm. In this nanoscale regime, quantum physics becomes critically important, like energy quantization effects of the narrow channel and the leakage currents due to tunneling. It has also been utilized to build novel devices, such as the band-to-band tunneling field-effect transistors (FETs). Therefore, it presages accurate quantum transport simulations, which not only allow quantitative understanding of the device performances but also provide physical insight and guidelines for device optimizations.
However, quantum transport simulations usually require solving repeatedly the Green’s function or the wave function of the whole device region with open boundary treatment, which are computationally cumbersome. Moreover, to overcome the short-channel effects, modern devices usually employ multi-gate structures that are three-dimensional, making the computation very challenging. It is the major target of this thesis to enhance the simulation efficiency by proposing several fast numerical algorithms. The other target is to apply these algorithms to study the physics and performances of some emerging electronic devices.
First, an efficient method is implemented for real space simulations with the effective mass approximation. Based on the wave function approach, asymptotic waveform evaluation combined with a complex frequency hopping algorithm is successfully adopted to characterize electron conduction over a wide energy range. Good accuracy and efficiency are demonstrated by simulating several n-type multi-gate silicon FETs. This technique is valid for arbitrary potential distribution and device geometry, making it a powerful tool for studying n-type silicon nanowire (SiNW) FETs in the presence of charged impurity and surface roughness scattering.
Second, a model order reduction (MOR) method is proposed for multiband simulation of nanowire structures. Employing three- or six-band k.p Hamiltonian, the non-equilibrium Green’s function (NEGF) equations are projected into a much smaller subspace constructed by sampling the Bloch modes of each cross-section layer. Together with special sampling schemes and Krylov subspace methods for solving the eigenmodes, large cross-section p-type SiNW FETs can be simulated. A novel device, junctionless FET, is then investigated. It is found that its doping density, channel orientation, and channel size need to be carefully optimized in order to outperform the classical inversion-mode FET.
With a spurious band elimination process, the MOR method is subsequently extended to the eight-band k.p model, allowing simulation of band-to-band tunneling devices. In particular, tunneling FETs with indium arsenide (InAs) nanowire channel are studied, considering different channel orientations and configurations with source pockets. Results suggest that source pocket has no significant impact on the performances of the nanowire device due to its good electrostatic integrity.
At last, improvements are made for open boundary treatment in atomistic simulations. The trick is to condense the Hamiltonian matrix of the periodic leads before calculating the surface Green’s function. It is very useful for treating leads with long unit cells.published_or_final_version
Electrical and Electronic Engineering
Doctoral
Doctor of Philosophy
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Mendoza, Maria Nimfa F. "Essays in production theory : efficiency measurement and comparative statics." Thesis, University of British Columbia, 1989. http://hdl.handle.net/2429/30734.
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Nonparametric linear programming tests for consistency with the hypotheses of technical efficiency and allocative efficiency for the general case of multiple output-multiple input technologies are developed in Part I. The tests are formulated relative to three kinds of technologies — convex, constant returns to scale and quasiconcave technologies. Violation indices as summary indicators of the distance of an inefficient observation from an efficient allocation are proposed. The consistent development of the violation indices across the technical efficiency and allocative efficiency tests allows us to obtain comparative measures of the degrees of technical inefficiency and pure allocative inefficiency. Constrained optimization tests applicable to cases where the producer is restricted to optimizing with respect to a subset of goods are also proposed. The latter tests yield the revealed preference-type inequalities commonly used as tests for consistency of observed data with profit maximizing or cost minimizing behavior as limiting cases. Computer programs for implementing the different tests and sample results are listed in the appendix.
In part II, an empirical comparison of nonparametric and parametric measures of technical progress for constant returns to scale technologies is performed using the Canadian input-output data for the period 1961-1980. The original data base was aggregated into four sectors and ten goods and the comparison was done for each sector. If we assume optimizing behavior on the part of the producers, we can reinterpret the violation indices yielded by the efficiency tests in part I as indicators of the shift in the production frontier. More precisely, the violation indices can be considered nonparametric chained indices of technical progress. The parametric measures of technical progress were obtained through econometric profit function estimation using the generalized McFadden flexible functional form with a quadratic spline model for technical progress proposed by Diewert and Wales (1989). Under the assumption of constant returns, the index of technical change is defined in terms of the unit scale profit function which gives the per unit return to the normalizing good. The empirical results show that the parametric estimates of technical change display a much smoother behavior which can be attributed to the incorporation of stochastic disturbance terms in the estimation procedure and, more interestingly, track the long term trend in the nonparametric estimates.
Part III builds on the theory of minimum wages in international trade and is a theoretical
essay in the tradition of analyzing the effects of factor market imperfections on resource allocation. The comparative static responses of the endogenous variables — output levels, employment levels of fixed-price factors with elastic supply and flexible prices of domestic resources — to marginal changes in the economy's exogenous variables — output prices, fixed factor prices and endowments of flexibly-priced domestic resources -— are examined. The effect of a change in a fixed factor price on other flexible factor prices can be decomposed Slutsky-like into substitution and scale effects. A symmetry condition between fixed factor prices and flexible factor prices is obtained which clarifies the concepts of "substitutability" and "complementarity" between these two kinds of factors. As an illustration, the model is applied to the case of a devaluation in a two-sector small open economy with rigid wages and capital as specific factors. The empirical implementation of the general model for the Canadian economy is left to more able econometricians but a starting point can be the sectoral analysis performed in Part II.Arts, Faculty of
Vancouver School of Economics
Graduate
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deCamp, Philip Draper. "The efficiency of nonparametric inference methods based on confidence interval lengths." Diss., Georgia Institute of Technology, 1997. http://hdl.handle.net/1853/25510.
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POSCHKE, Markus. "Firm heterogeneity and macroeconomic performance." Doctoral thesis, European University Institute, 2007. http://hdl.handle.net/1814/10310.
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Defence date: 7 December 2007Examining Board: Prof. Omar Licandro, (EUI) ; Prof. Salvador Ortigueira, (EUI) ; Prof. Russell Cooper, (University of Texas at Austin) ; Prof. Jaume Ventura, (CREI, Universitat Pompeu Fabra)
PDF of thesis uploaded from the Library digital archive of EUI PhD theses
The regulation of entry and aggregate productivity Euro Area economies have lower firm turnover rates, lower total factor and labor productivity, and higher capital intensity than the Unites States. I argue that differences in entry cost contribute to this pattern by affecting firms' technology choice. Introducing technology choice into a standard heterogeneous firm model, small differences in administrative entry cost suffice to explain 10-20% of differences in total factor productivity and the capital-output ratio. The productivity difference arises because higher equilibrium capital intensity acts as an entry barrier and protects low-productivity incumbents. Both firm heterogeneity and technology choice are crucial for strengthening results compared to previous studies. 2 Employment protection, firm selection, and growth This paper analyzes the effect of ring costs on aggregate productivity growth. For this purpose, a model of endogenous growth through selection and imitation is developed. It is consistent with recent evidence on firm dynamics and on the importance of reallocation for productivity growth. In the model, growth is driven by selection among heterogeneous incumbent firms, and is sustained as entrants imitate the best incumbents. In this framework, firing costs not only induce misallocation of labor, but also affect growth by affecting firms' exit decisions. Importantly, charging firing costs only to continuing firms raises growth by promoting selection. Also charging them to exiting firms is akin to an exit tax, hampers selection, and reduces growth { by 0.1 percentage points in a calibrated version of the model. With job turnover very similar in the two settings, this implies that the treatment of exiting firms matters for welfare. In addition, the impact on growth rates is larger in sectors where firms face larger idiosyncratic shocks, as in services. This fits evidence that recent EU-US growth rate differences are largest in these sectors and implies that firing costs can play a role here. A brief empirical analysis of the impact of firing costs on the size of exiting firms supports the model's conclusions. 3 The labor market, the decision to become an entrepreneur, and the firm size distribution Why do some people become entrepreneurs, and how do labor markets affect this choice? This paper addresses this question using a matching model with occupational choice and heterogeneity in both ability as a worker and ex ante unknown productivity of firm start-ups. Key effects are the following: labor market conditions affect incentives to start firms differently for workers and the unemployed, with repercussions on aggregate productivity; and they affect the expected value of firm creation due to the possibility of failure. These effects go beyond the standard impact of labor market conditions on firms' employment policy and value. The correlation of observed productive ability and potential productivity significantly shapes the firm size distribution, suggesting that the empirical correlation is positive but far from perfect. Finally, the model allows for a comparatively flexible lower tail of the firm size distribution and can explain the existence and persistence of small, lowproductivity firms with low profits: their owners have low outside options in the labor market.
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Epple, Alexander. "Methods for increased computational efficiency of multibody simulations." Diss., Atlanta, Ga. : Georgia Institute of Technology, 2008. http://hdl.handle.net/1853/26532.
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Thesis (Ph. D.)--Aerospace Engineering, Georgia Institute of Technology, 2009.Committee Chair: Olivier A. Bauchau; Committee Member: Andrew Makeev; Committee Member: Carlo L. Bottasso; Committee Member: Dewey H. Hodges; Committee Member: Massimo Ruzzene. Part of the SMARTech Electronic Thesis and Dissertation Collection.
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Johnson, Andrew. "Methods in productivity and efficiency analysis with applications to warehousing." Diss., Atlanta, Ga. : Georgia Institute of Technology, 2006. http://hdl.handle.net/1853/29400.
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Thesis (Ph.D)--Industrial and Systems Engineering, Georgia Institute of Technology, 2006.McGinnis, Leon - Committee Chair, Griffin, Paul - Committee Member, Hackman, Steve - Committee Member, Parsons, Len - Committee Member, Sharp, Gunter - Committee Member. Part of the SMARTech Electronic Thesis and Dissertation Collection.
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Wang, You-song, and 王幼松. "An analysis of the technical efficiency in Hong Kong's construction industry." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1998. http://hub.hku.hk/bib/B31239420.
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Palmer, Kurt D. "Data collection plans and meta models for chemical process flowsheet simulators." Diss., Georgia Institute of Technology, 1998. http://hdl.handle.net/1853/24511.
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Zawartka-Czekaj, Monika, and P. G. Pererva. "Economic methods of waste management in Poland and Ukraine." Thesis, NTU "KhPI", 2016. http://repository.kpi.kharkov.ua/handle/KhPI-Press/27082.
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Discussed the theoretical-methodical principles of cost management in transitive economy. The features of cost management in the Ukrainian and Polish economies.Розглянуто теоретико-методичні положення управління витратами в транзитивній економіці. Досліджено особливості менеджменту витрат в українській та польській економіці.
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Takaidza, Isaac. "Modelling the optimal efficiency of industrial labour force in the presence of HIV/AIDs pandemic." Thesis, Cape Peninsula University of Technology, 2012. http://hdl.handle.net/20.500.11838/1305.
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Thesis (DTech (Mechanical Engineering))--Cape Peninsula University of Technology, 2012In this thesis, we investigate certain key aspects of mathematical modelling to explain the epidemiology of HIV/AIDS at the workplace and to assess the potential benefits of proposed control strategies. Deterministic models to investigate the effects of the transmission dynamics of HIV/AIDS on labour force productivity are formulated. The population is divided into mutually exclusive but exhaustive compartments and a system of differential equations is derived to describe the spread of the epidemic. The qualitative features of their equilibria are analyzed and conditions under which they are stable are provided. Sensitivity analysis of the reproductive number is carried out to determine the relative importance of model parameters to initial disease transmission. Results suggest that optimal control theory in conjunction with standard numerical procedures and cost effective analysis can be used to determine the best intervention strategies to curtail the burden HIV/AIDS is imposing on the human population, in particular to the global economy through infection of the most productive individuals. We utilise Pontryagin’s Maximum Principle to derive and then analyze numerically the conditions for optimal control of the disease with effective use of condoms, enlightenment/educational programs, treatment regime and screening of infectives. We study the potential impact on productivity of combinations of these conventional control measures against HIV. Our numerical results suggest that increased access to antiretroviral therapy (ART) could decrease not only the HIV prevalence but also increase productivity of the infected especially when coupled with prevention, enlightenment and screening efforts.
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MACEDO, Rafael Feliciano de. "Secagem contínua de argila bentonita em secador rotativo industrial: modelagem, simulação e experimentação." Universidade Federal de Campina Grande, 2016. http://dspace.sti.ufcg.edu.br:8080/jspui/handle/riufcg/1501.
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Capes
O presente trabalho trata do estudo teórico e experimental do processo de secagem de argila bentonita em secador rotativo contínuo industrial. Foram realizados testes experimentais em campo, onde foi possível coletar e medir parâmetros geométricos do secador, fluxo mássico, temperatura do ar e do material. Foi estabelecido um modelo matemático a ser utilizado para a análise da eficiência global teórica idealizada e real do secador rotativo. Resultados teóricos do teor de umidade, temperatura do ar e do material na saída do secador, além da eficiência global do equipamento em várias condições de secagem foram apresentados e analisados. Verificou-se que o modelo real da simulação mostrou que o secador rotativo quando operado em certas condições ambientes na planta de instalação possui eficiência e desempenho adequado conforme sugere a literatura. Parâmetros como tempo de residência, velocidade rotacional e velocidade do ar quando manipulados corretamente pode-se obter melhores resultados na secagem do produto de argila bentonita visando a redução do consumo de combustível. Além dos testes dos parâmetros, sugestões para futuros estudos como, a determinação da cinética de secagem e curvas de sorção da argila são de essencial importância para garantir a especificação do teor de umidade final do produto.
The present work deals with the theoretical and experimental study of the drying process of bentonita clay in an industrial continuous rotary dryer. Experimental tests were performed in the field, where it was possible to collect and measure geometric parameters of the dryer, mass flow, air and material temperature. It was proposed a mathematical model to be used for the analysis of the idealized and real theoretical global efficiency of the rotary dryer. Theoretical results of moisture content, air temperature and material at the dryer outlet, besides the overall equipment efficiency under various drying conditions were presented and analyzed. It was verified that the real simulation model showed that the rotary dryer when operated in certain ambient conditions in the installation plant has efficiency and adequate performance as suggested by the literature. Parameters such as residence time, speed of rotation and air velocity when handled properly, better results can be obtained in the drying of the bentonita clay product in order to reduce fuel consumption. In addition to the parameter tests, as future studies, the determination of drying kinetics and sorption curves of the clay are of essential importance to ensure the specification of the final moisture content of the product.
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Narisetty, Murali Krishna. "Methods in order batching for picking in an order picking distribution center." Ohio : Ohio University, 2002. http://www.ohiolink.edu/etd/view.cgi?ohiou1174920072.
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Gaigalaitė, Laura. "Statybos investicijų efektyvumo analizė taikant matematinio modeliavimo metodą." Master's thesis, Lithuanian Academic Libraries Network (LABT), 2005. http://vddb.library.lt/obj/LT-eLABa-0001:E.02~2005~D_20050627_122512-82077.
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Pagrindinė šio darbo užduotis yra statybos investicijų efektyvumo analizė taikant matematinio modeliavimo metodus. Darbą sudaro trys pagrindiniai skyriai.
Apžvalginiame skyriuje atlikta įvairių pasaulio šalių mokslininkų investicijų efektyvumo nustatymo modelių analizė. Pateikti vieni naujausių mokslinėje literatūroje aptinkamų metodų, taikomų investicijoms skaičiuoti. Apžvelgti finansinių (klasikinių) investicijų efektyvumo vertinimo metodų trūkumai. Apibrėžtos pagrindinės matematinio modeliavimo sąvokos, taikymo sritys bei pagrindiniai matematinių modelių sudarymo principai.
Antrasis skyrius skirtas investicinių projektų sudėties ir jų vertinimo principų apžvalgai. Apibrė��ta bendroji bei investicijų statyboje koncepcija, statybos investicinių projektų klasifikacija. Pateikta uždavinių, padedančių nustatyti statybos investicijų efektyvumą, klasifikacija bei statybos investicijų efektyvumo nustatymo etapai. Toliau gilinamasi į bendruosius investicinio projekto vertinimo principus, pateikiama schema, apibrėžianti investicinių projektų vertinimo eigą.
Trečiojoje dalyje, pereinant prie statybos investicinių procesų analizės, pateikiama rinkos ir statistinių duomenų apžvalga, kadangi būtent šių duomenų pagrindu sudaromas matematinis modelis, nuo jų tikslumo priklauso galutiniai skaičiavimų rezultatai. Statistinių duomenų apdorojimo programa MINITABTM, regresinės analizės metodu, sudaromas matematinis modelis, nustatantis statybos investicinio proceso efektyvumą. Remiantis... [to full text]The main task of this project is the analysis of the construction investment efficiency, by applying of mathematical modeling methods. The model is created in order to define the effectiveness of the construction investment process. According to the model, it was calculated the yield of the process and the risk zones.
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Friberg, Martin, and Eric Ringtun. "Prefabricerade innerväggar : Kostnad- och tidseffektivitet för lätta prefabricerade innerväggar." Thesis, KTH, Byggvetenskap, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-174127.
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Kostnad och tid är två parametrar som går hand i hand i näst intill alla sammanhang, inte minst i byggbranschen. Pressade tidsplaner och snäva budgetar kräver noggrannhet och effektivitet genom samtliga skeden i byggprocessen. Framför allt är en kortare byggtid av stor vikt, som ett resultat av det har det industriella byggandet fått en alltmer betydande roll. Syftet med denna rapport är att undersöka lönsamheten vid användandet av prefabricerade element gentemot konventionell platsbyggning. Arbetet har avgränsats till att undersöka ett enskilt område, nämligen lätta innerväggar. Rapporten har gjorts i samarbete med Peab AB och den har utförts på deras pågående projekt, köpcentrumet Mall of Scandinavia i Arenastaden, Solna. De två byggmetoderna har jämförts med avseende på tid och ekonomi. Vidare har de prefabricerade väggelelementens för- och nackdelar samt alternativa användningsområden undersökts. De prefabricerade innerväggarna som används i projektet tillverkas av företaget Elementum Eco AB i Bollebygd. Monteringen av väggelementen sker med hjälp av en modifierad gaffeltruck, vilket är ovanligt. Metoden kräver endast tre arbetare och medför en avsevärt kortare monteringstid jämfört med platsbyggda innerväggar. Metoden är ny för Peab och det är andra gången som de valt att använda sig av den. Det var vid ett tidigare projekt i Tanums kommun, då köpcentrumet Tanum shoppingcenter byggdes, som metoden introducerades för företaget. Efter färdigställandet var erfarenheterna av väggelementen positiva. Man ansåg sig ha vunnit både tids- och kostnadsmässigt och valde därför att bepröva metoden ytterligare en gång. Jämförelsen mellan de båda byggmetoderna har gjorts på två väggar med samma förutsättningar vad gäller dimension och arbetskraft. Fördjupade intervjuer som huvudmetod, egenhändigt utförda inspektioner och litteraturstudie har föranlett resultat i rapport. Resultatet av detta arbete visar att kostnads- och tidseffektiviteten ökar med en faktor på upp till närmare nio gånger, genom val av prefabricering som metod jämfört med konventionell platsbyggning som metod. Flera fördelar påvisas även inom områden som arbetsmiljö och miljöpåverkan.Cost and time are two parameters that affect one another no matter what the context is, not least in the building industry. Both time schedules and budgets are pushed to the limit, therefore accuracy and efficiency needs to be considered through all stages of the building process. A shorter construction time is of vital importance and as a result of that, industrial building methods has taken a more significant part in the business. The purpose of this report was to investigate the profitability by using prefabricated panels instead of conventional building methods. Due to a given timeframe the investigation has been defined to focus on one special field, namely light prefabricated interior walls. The report was developed in collaboration with Peab AB and the work has been done on their ongoing project Mall of Scandinavia in Arenastaden, Solna. The two construction methods have been compared with respect to time and finances. Furthermore, the prefabricated panels advantages and disadvantages as well as alternative uses have been studied. The prefabricated interior walls, used in the project, are produced by Elementum Eco AB in Bollebygd. The walls are mounted by means of a modified forklift truck, which is somewhat unique. The mounting process requires only three workers and results in a considerably shorter assembly time compared to site-built interior walls. It is a new method and it is used by Peab for the second time. The company was introduced to the method at an earlier project in Tanum, when Tanum shopping centre was established. The over all experience turned out positive and once completed, both time and cost was considered to have been saved. Peab therefore chose to use the method once more. The comparison between the two methods of construction has been made on two walls with similar conditions in terms of size and manpower. The result of this report shows that both time and cost efficiency can increase nearly nine times by choosing prefabricated interior walls compared to conventional site-built ones. Furthermore, benefits in areas such as environmental impact and work environment are shown as well.
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Maredza, Andrew. "Profit incentives and technical efficiency in the provision of health care in Zimbabwe: an application of data envelopment analysis and econometric methods." Thesis, University of Fort Hare, 2009. http://hdl.handle.net/10353/294.
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This study examines issues surrounding efficiency in the Zimbabwean health sector with specific emphasis on for-profit hospitals in order to find out whether they are significantly more efficient than non-profit hospitals. The study attempts to explore the significance of profit incentives on efficiency. This study uses the Data Envelopment Analysis (DEA) methodology to examine hospital efficiency scores for the 100 hospitals in the sample classified as for-profit, mission and public. Outputs of the study include inpatient days and outpatient visits. The number of beds, doctors and nurses were used to capture hospital inputs. The findings indicated that there was a marked deviation of efficiency scores from the best practice frontier with for-profit hospitals having the highest mean PTE of 71.1 percent. The mean PTE scores for mission and public hospitals were 64.8 percent and 62.6 percent respectively. About 85 percent, 83 percent and 91 percent of the for-profit, mission and public hospitals were found to be operating below their average PTE. More than half of the hospitals are being run inefficiently. Of more importance to this study is the fact that the hypothesis of for-profit hospital superiority was accepted implying that for profit hospitals are significantly more efficient than the non-profit category. The study indicated that the amount of inputs being used could be decreased substantially without decreasing the quantity of outputs achieved. In each of the hospitals included in the study, the total input reductions needed to make inefficient hospitals efficient are more than 50 percent. These input savings could go a long way in achieving other health concerns without mobilizing additional resources in the sector
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Gunnarsson, Helene. "Supply chain optimization in the forest industry /." Linköping : Department of Mathematics, Linköpings universitet, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-8856.
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Lan, Tian. "MATHEMATICAL MODELING FOR PLATFORM-BASED PRODUCT CONFIGURATION CONSIDERING TOTAL LIFE-CYCLE SUSTAINABILITY." UKnowledge, 2015. http://uknowledge.uky.edu/me_etds/56.
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Many companies are using platform-based product designs to fulfill the requirements of customers while maintaining low cost. However, research that integrates sustainability into platform-based product design is still limited. Considering sustainability during platform-based design process is a challenge because the total life-cycle from pre-manufacturing, manufacturing and use to post-use stages as well as economic, environmental and societal performance in these stages must be considered. In this research, an approach for quantifying sustainability is introduced and a mathematical model is developed for identifying a more sustainable platform. Data from life-cycle assessment is used to quantify environmental factors; criteria from the Product Sustainability Index (ProdSI) are used to quantify societal factors. The Analytic Hierarchical Process method is used to assess relative importance of societal factors and the weighted sum method is used in the objective function for overall multi-objective optimization. A bicycle platform configuration will be used as a case study to demonstrate the application of the model. The relationship between commonality of the platform and sustainability performance is analyzed.
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Harris, Steven C. "A genetic algorithm for robust simulation optimization." Ohio : Ohio University, 1996. http://www.ohiolink.edu/etd/view.cgi?ohiou1178645751.
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Burnett, Sulene. "A simplified numerical decision making toolbox for physical asset management decisions." Thesis, Stellenbosch : Stellenbosch University, 2013. http://hdl.handle.net/10019.1/85626.
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Thesis (MEng)--Stellenbosch University, 2013.ENGLISH ABSTRACT: The management of physical assets has become a popular eld of study over recent years and is being acknowledged in multiple disciplines world wide. In this project, research on Physical Asset Management (PAM), maintenance and decision making are presented. PAM is a complex subject and requires the participation of multiple disciplines in order to successfully manage physical assets. Moreover, the management of maintenance makes a big contribution in achieving successful PAM. Decision making is a core element to manage maintenance e ciently, both on strategic and operational level. Various methods and techniques can be used to aid the decision making process such as, using past experience, xed decision making techniques and techniques involving numerical calculations, to mention only a few. However, using numerical calculations to make decisions are not very popular. This is due to various reasons, for example the inherent complexity of the mathematics and the time required to execute such calculations are disliked. People tend to avoid complex numerical calculations and rather rely on past experience and discussion of circulating opinions to make decisions. This is not ideal and can lead to inconsistent and inaccurate decisions. In this project, the importance of numerical decision making is researched, especially in maintenance related decisions. The focus is placed on the simpli cation of numerical decision making techniques with the aim to make it easy and quick to use to support operational PAM decisions. Di erent decisions regarding PAM, especially decisions with regards to managing maintenance in order to achieve PAM, are discussed by means of a literature study. This is done to clarify the applicability of using numerical decision making techniques to support this type of decisions. A few di erent available numerical techniques are highlighted that can be used to support the decision making process. The decisions together with numerical decision making techniques are evaluated in order to combine the most appropriate techniques in a simpli ed manner. The purpose of this is that it can be used by anyone with the necessary knowledge of a speci c system or operation. As a result a simpli ed numerical decision making toolbox is developed that can support maintenance related decision. This toolbox is applied to a real life situation by means of a case study, made possible by Anglo American Platinum Limited (Amplats). An evaluation and validation of the toolbox is done through the case study to conclude wether it has value in practice or not.
AFRIKAANSE OPSOMMING: Die bestuur van siese bates het die afgelope paar jaar 'n gewilde studieveld geword en word erken in verskeie dissiplines reg oor die w^ereld. In hierdie projek word navorsing gedoen oor Fisiese Bate Bestuur (FBB), instandhouding en besluitneming. FBB is 'n komplekse onderwerp en vereis die deelname van verskeie dissiplines om sukses te behaal. Die bestuur van instandhouding maak 'n groot bydrae tot suksesvolle FBB. 'n Kern element van doeltre ende instandhouding is besluitneming, beide op strategiese en operasionele vlak. Verskillende metodes en tegnieke kan gebruik word om die besluitnemingsproses te ondersteun soos byvoorbeeld om gebruik te maak van ondervinding en vorige gebeurtenisse, vaste besluitnemingstegnieke, tegnieke wat numeriese berekeninge gebruik en nog meer. Die gebruik van numeriese metodes om besluite te neem is nie baie gewild nie. Dit is as gevolg van verskeie redes soos byvoorbeeld die inherente kompleksiteit en ingewikkeldheid van die wiskunde en ook die tyd wat benodig word om sulke berekeninge uit te voer. Mense is geneig om ingewikkelde numeriese berekeninge te vermy en eerder staat te maak op vorige ervaring en die bespreking van menings om besluite te neem. Dit is nie ideaal nie en kan lei tot onkonsekwente besluite, of selfs verkeerde besluite. In hierdie projek is die belangrikheid van numeriese besluitneming nagevors, veral in die onderhoudsverwante besluite. Die fokus word geplaas op die vereenvoudiging van die numeriese besluitnemings tegnieke. Die doel is om dit op so 'n manier te vereenvoudig dat dit maklik en vinnig is om te gebruik vir operasionele FBB besluite. Verskillende besluite oor FBB, veral besluite met betrekking tot instandhouding om suksesvolle FBB te bereik, word bespreek deur middel van 'n literatuurstudie. Die literatuurstudie ondersoek die toepaslikheid van die gebruik van numeriese besluitnemingstegnieke vir hierdie soort besluite. 'n Paar verskillende beskikbare numeriese tegnieke wat gebruik kan word om die besluitnemingsproses te ondersteun word uitgelig. Die besluite, saam met numeriese besluitnemingtegnieke, word ge evalueer om die mees gepaste tegnieke te kombineer in 'n vereenvoudigde manier. Uiteindelik moet dit deur enige iemand met die nodige kennis van 'n spesi eke stelsel of proses gebruik kan word. As resultaat is 'n vereenvoudigde numeriese besluitnemingstegniekkombinasie ontwikkel wat besluite verwant aan instandhouding kan ondersteun. Hierdie tegniek-kombinasie word toegepas in 'n werklike situasie deur middel van 'n gevallestudie, wat moontlik gemaak is deur Anglo American Platinum Limited. 'n Evaluering en validering van die tegniek-kombinasie word gedoen in die gevallestudie om te bepaal of dit wel waarde het in die praktyk of nie.
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Islam, Ziaul. "A design of experiment approach to tolerance allocation." Ohio : Ohio University, 1995. http://www.ohiolink.edu/etd/view.cgi?ohiou1179428292.
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Farrell, Troy W. "The mathematical modelling of primary alkaline battery cathodes." Thesis, Queensland University of Technology, 1998.
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Malmgren, Henrik. "Revision of an artificial neural network enabling industrial sorting." Thesis, Uppsala universitet, Institutionen för teknikvetenskaper, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-392690.
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Convolutional artificial neural networks can be applied for image-based object classification to inform automated actions, such as handling of objects on a production line. The present thesis describes theoretical background for creating a classifier and explores the effects of introducing a set of relatively recent techniques to an existing ensemble of classifiers in use for an industrial sorting system.The findings indicate that it's important to use spatial variety dropout regularization for high resolution image inputs, and use an optimizer configuration with good convergence properties. The findings also demonstrate examples of ensemble classifiers being effectively consolidated into unified models using the distillation technique. An analogue arrangement with optimization against multiple output targets, incorporating additional information, showed accuracy gains comparable to ensembling. For use of the classifier on test data with statistics different than those of the dataset, results indicate that augmentation of the input data during classifier creation helps performance, but would, in the current case, likely need to be guided by information about the distribution shift to have sufficiently positive impact to enable a practical application. I suggest, for future development, updated architectures, automated hyperparameter search and leveraging the bountiful unlabeled data potentially available from production lines.
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Iqbal, Fowad. "Generate light with wind power." Thesis, Tekniska Högskolan, Högskolan i Jönköping, JTH. Forskningsmiljö Produktutveckling - Simulering och optimering, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:hj:diva-21124.
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The report explain the steps taken to improve a product (SOLVINDEN), which uses sun and wind energy to generate light and is used for outdoor decoration. The research involves improvements in both designas well function. As the form follows function in the product functionality of the form is very important in selection of the form. Some of important topics which are considered are different way of using wind to charge batteries, blades profiles and shape, way of optimizing generator, ratio of the optimal solution between of how much wind power is needed tostart charging and charging efficiency. The report also includes differentway of manufacturing, testing and finalizing the right form afteroptimizing. The solar power and the batteries are not in the scope of theproject.
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Scullin, Michelle E. "Integrating Value Stream Mapping and Simulation." Diss., CLICK HERE for online access, 2005. http://contentdm.lib.byu.edu/ETD/image/etd898.pdf.
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Янковець, Т. М. "Вплив ефективності праці на підвищення ефективності бізнесу промислових підприємств." Thesis, Kaunas, Lithuania: Baltija Publishing, 2017. https://er.knutd.edu.ua/handle/123456789/8579.
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Досліджено проблему підвищення ефективності праці працівників підприємства, задіяних у здійсненні його операційної діяльності. Виявлено напрями та резерви зростання продуктивності праці. Досліджено процес нормування витрат часу як одного з важливих напрямів управління операційною діяльністю промислового підприємства.
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Abreu, Thiago Probst de. "Algoritmos de controle para melhoria da regulação de tensão de alternadores de rotação variada." Universidade Tecnológica Federal do Paraná, 2017. http://repositorio.utfpr.edu.br/jspui/handle/1/2595.
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Esta dissertação apresenta um estudo e avaliação de algoritmos de controle para a melhoria da regulação de tensão de alternadores de rotação variada. Muitos algoritmos de controle de tensão de geradores são apresentados pela literatura, porém poucos são os trabalhos que mostram resultados confiáveis o suficiente para garantir que sejam utilizados em qualquer aplicação deste tipo. Além disso, o problema de mudança de rotação do gerador não é abordado pela literatura, fato marcante em aplicações de geradores nas áreas navais e ferroviárias. Portanto, um estudo comparativo faz-se necessário, considerando algumas métricas pré-definidas, para que uma técnica seja escolhida e então aplicada e avaliada em um regulador automático de tensão, AVR (Automatic Voltage Regulator), digital controlado por um sistema embarcado em um gerador real. Este estudo é apresentado neste trabalho, que avalia dois algoritmos de otimização de controlador PID com ajuste off-line, o algoritmo de otimização por enxame de partículas ou PSO (Particle Swarm Optimization), e o algoritmo genético ou GA (Genetic Algorithm). O ajuste do controlador é realizado em um ambiente de simulação, onde o modelo matemático do alternador é obtido, através de ensaios, para que a sintonia do controlador seja a mais correta possível. Os algoritmos são comparados considerando o tempo de subida, tempo de estabilização, erro em regime, sobressinal e tempo de sintonia como métricas, obtendo uma melhor resposta do PSO comparando-a com o GA através de simulações, e validando-a, através de comparação com um algoritmo já utilizado, em um AVR digital em um gerador real.This work presents a study of control algorithms to improve the voltage regulation of varied rotation alternators. Many voltage control algorithms are presented in the literature, but most of them do not present enough results to guarantee their usage in locomotive applications. In addition, the generator speed change is not addressed on the mathematical models used in voltage regulation control algorithms in the literature. Therefore, a comparative study is necessary, following some pre-defined metrics, so that a technique could be proposed and then applied and evaluated in a digital Automatic Voltage Regulator (AVR) controlled by an embedded system in a real generator. This study evaluates two PID controller optimization algorithms with off-line tuning, PSO (Particle Swarm Optimization) and GA (Genetic Algorithm). The controller tuning is performed in a simulation environment, where the mathematical model of the alternator is obtained through tests. The algorithms are compared considering the rise time, settling time, steady-state error, overshoot and tuning time as comparison metrics. A better response from the PSO is obtained through simulations, and this response is validated in a digital AVR on a real generator.
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Machado, Marcio Bezerra. "Modelagem tridimensional da dispersão de poluentes em rios." [s.n.], 2006. http://repositorio.unicamp.br/jspui/handle/REPOSIP/267414.
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Orientadores: Jose Roberto Nunhez, Edson TomazTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Quimica
Made available in DSpace on 2018-08-06T01:51:29Z (GMT). No. of bitstreams: 1 Machado_MarcioBezerra_D.pdf: 3569468 bytes, checksum: 4c69c5d76d7d79aa717808b84c4701d2 (MD5) Previous issue date: 2006
Resumo: Estudos têm mostrado que a humanidade enfrentará severa falta de água nas próximas décadas. Muitos esforços têm sido direcionados para o desenvolvimento de novas ferramentas computacionais a fim de se garantir uma melhor utilização dos recursos hídricos. Diversos estudos estão sendo realizados utilizando ferramentas de CFD (Computational Fluid Dynamics) para obtenção de novas formas de gerenciamento destes recursos. Neste contexto, é de suma importância o desenvolvimento de novas técnicas para predizer o impacto ambiental causado por emissões industriais em rios de modo que estratégias possam ser planejadas para diminuir os efeitos desta poluição. Este trabalho apresenta um modelo Fluidodinâmico Computacional tridimensional para simular a dispersão de substâncias solúveis em rios. O método dos volumes finitos foi utilizado para aproximar as equações de conservação de momento, de massa e de espécie química. O sistema de coordenadas cartesianas foi escolhido para representar o sistema. Foi utilizado um modelo algébrico de turbulência de ordem zero. O modelo de StreeterPhelps foi usado para predizer a concentração de substâncias orgânicas e de oxigênio dissolvido ao longo do rio. O modelo pode também predizer o impacto causado pela ocorrência de múltiplos pontos de emissão no trecho estudado. O modelo matemático foi desenvolvido em linguagem Fortran. Os resultados mostram que a metodologia proposta é uma boa ferramenta para a avaliação do impacto ambiental causado pela emissão de efluentes em rios. O software é bastante rápido, especialmente quando comparado com outros pacotes de CFD disponíveis comercialmente. Foram feitas comparações entre os resultados numéricos e dados experimentais coletados no rio Atibaia. Os resultados numéricos apresentaram uma boa concordância com os dados coletados experimentalmente
Abstract: A future lack of water in the next decades has been observed by many studies. Much effort has been devoted to find strategies which will help to manage proper1y water resources. Theoretical studies have been used recent1y since the scope of computational fluid dynamics (CFD) has increased, allowing its use in the issue of water quality. In this scenario, it is important to develop new techniques to predict the environmental impact of emissions in rivers so that strategies can be devised to decrease the effects of pollution. This work presents a three-dimensional Computational Fluid Dynamics (CFD) in house model to simulate the dispersion of soluble substances in a river. The finite volume method is used to approximate the momentum, mass and species conservation equations. A Cartesian coordinate system has been chosen to represent the river. Turbulence is taken into account by a zero-order equation model. The Streeter-Phelps model has been used to predict the concentration of organic substances and dissolved oxygen along the river. The model can also predict the impact of multiple effluents discharges. Results show that the proposed methodology is a good tool for the evaluation of the environmental impact caused for pollutants emissions in rivers. The software has been developed from the model and use the Fortran language. It is very fast, especially when compared to available commercial CFD packages. Experimental comparisons for soluble substances dispersion have been made for the Atibaia River. The results show good agreement with experimental data
Doutorado
Desenvolvimento de Processos Químicos
Doutor em Engenharia Química
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Azem, Sadia. "Ordonnancement des systemes flexibles de production sous contraintes de disponibilite des ressources." Phd thesis, Ecole Nationale Supérieure des Mines de Saint-Etienne, 2010. http://tel.archives-ouvertes.fr/tel-00611830.
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La majeure partie des travaux sur les problèmes d'ordonnancement se placent dans le contexte où les ressources sont disponibles en permanence. Ce qui en réalité n'est pas toujours le cas. Nous nous plaçons dans le contexte d'indisponibilités connues ; nous nous intéressons plus particulièrement aux problèmes de type job shop avec des périodes d'indisponibilité flexibles et des tâches pouvant éventuellement être interrompues par les périodes d'indisponibilité. L'intégration de ces contraintes rend les problèmes d'ordonnancement nettement plus difficiles à résoudre. La flexibilité que nous considérons peut être relative à au moins l'un des points suivants : déplacement de la période d'indisponibilité dans une fenêtre de temps, modification de la durée de la période d'indisponibilité, interruption d'une tâche par une période d'indisponibilité, ensuite reprise avec une éventuelle pénalité.Dans cette thèse, nous avons proposé des modèles mathématiques pour le problème. En plus de la résolution des problèmes considérés, le but de ces modélisations est de permettre d'analyser l'impact des différentes contraintes et d'évaluer la qualité des méthodes approchées que nous proposons. Ces dernières permettent de construire très rapidement un ordonnancement en se basant sur des règles de priorité. Les solutions sont aussi utilisées pour notre approche basée sur la génération de colonnes. Cette approche s'adapte bien à différents fonctions objectif et permet d'intégrer relativement facilement plusieurs contraintes. De nombreuses expérimentations ont été menées pour valider les méthodes proposées.
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Meira, Marcelo da Silva. "Otimização de produção de uma linha de montagem mista na indústria automotiva por meio de programação matemática." Universidade Tecnológica Federal do Paraná, 2015. http://repositorio.utfpr.edu.br/jspui/handle/1/1892.
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Este trabalho utiliza a Programação Linear Inteira Mista (MILP) para investigar as diferenças de produtividade encontradas em uma Linha de Montagem de Modelo Misto. A abordagem de solução foi através da construção e resolução de modelos matemáticos do problema de balanceamento de linhas de montagem de modelo misto (MALBP – Mixed-Model Assembly Line Balancing Problem), seguido do problema de sequenciamento de carros (PSC – Car Sequencing Problem). Uma simulação discreta foi utilizada para verificar os resultados dos modelos matemáticos. O estudo relata o caso real de uma linha de montagem da indústria automotiva das partes móveis das carrocerias de três diferentes veículos compartilhando a mesma linha de produção. A linha de produção é caracterizada como baixa cadência (de até 15 veículos/hora) e totalmente manual. A linha é constituída por mesas de rolos em série onde o acionamento é do tipo de passo não sincronizado. O objetivo é investigar como manter o melhor nível de produtividade da linha de produção e, ao mesmo tempo, manter a característica de flexibilidade para atender a uma demanda variável em volume e diversidade de produto. São apresentados resultados desse trabalho que indicam que é possível a obtenção de alguns balanceamentos flexíveis para alguns mixes de produtos, o que permite manter a diferença nos tempos de produção no limite de 6%, para esta correta combinação de balanceamento-sequenciamento. No entanto, verificando as demais combinações possíveis para os seis mixes de produtos avaliados, o tempo de produção apresentou diferenças de até 19%, dependendo da sequência de entrada dos produtos para um certo mix. Outro fator que também ocasionou diferenças dos tempos produtivos, de 20% em média, foi em relação a alocação/ausência de postos pulmões (buffers). O horizonte da análise, a priori, foi de um lote de produção de uma hora para o modelo matemático e de uma semana de produção para o modelo de simulação discreta. Os resultados obtidos no estudo indicam que é possível operar uma linha de montagem flexível com uma produtividade equiparável a linhas de montagem de único modelo, se cuidados relativos ao balanceamento e sequenciamento produtivos forem observados. Por outro lado, se as condições operacionais de balanceamento e sequenciamento para as linhas de montagem de modelos/produtos mistos não forem consideradas, as perdas acumuladas na taxa de produção podem ser significativas (por exemplo, tempos de produção para algumas condições de teste ultrapassaram em 30% o valor teórico estimado).This work uses Mixed Integer Linear Programming (MILP) to investigate productivity differences found in a Mixed-Model Assembly Line. The solution approach was based on construction and resolution of mathematical models for the Mixed-Model Assembly Line Balancing Problem (MALBP), followed by the Car Sequencing Problem (CSP). A discrete simulation was used to check the results obtained by the mathematical models. The study reports the real case of an automotive metal line that assemblies the closures of three different vehicles, sharing the same production line. The production line is characterized as low cadence (e.g., up to 15 vehicles/hour) and fully manual. The line is formed by roller tables in series with unpaced devices. The main objective is to investigate how to maintain productivity, while maintaining the flexibility characteristic to meet a variable demand in volume and product diversity. Results of this study are presented and indicate that some flexible balancing mixes are viable. Production time differences of no more than 6% were observed in such flexible choices. However, the checking of some possible combinations for the six mixes of evaluated products showed a production time difference up to 19%, depending on the sequence of products for a certain mix. Another factor that also influenced production time differences, 20% on average, was the allocation of buffers. The horizon of analysis encompasses a lot of production of one hour, to the mathematical model, and a week for discrete simulation. The obtained results indicate that it is possible to operate a flexible assembly line with a level of productivity similar to a single product line, in case of careful choices in balancing/sequencing. On the other hand, if the operating conditions of balancing and sequencing were not taken into account the cumulative loss in throughput may be significant (e.g., for some studied cases, production time exceed 30% the theoretical value).
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Teng, Sin Yong. "Intelligent Energy-Savings and Process Improvement Strategies in Energy-Intensive Industries." Doctoral thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2020. http://www.nusl.cz/ntk/nusl-433427.
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S tím, jak se neustále vyvíjejí nové technologie pro energeticky náročná průmyslová odvětví, stávající zařízení postupně zaostávají v efektivitě a produktivitě. Tvrdá konkurence na trhu a legislativa v oblasti životního prostředí nutí tato tradiční zařízení k ukončení provozu a k odstavení. Zlepšování procesu a projekty modernizace jsou zásadní v udržování provozních výkonů těchto zařízení. Současné přístupy pro zlepšování procesů jsou hlavně: integrace procesů, optimalizace procesů a intenzifikace procesů. Obecně se v těchto oblastech využívá matematické optimalizace, zkušeností řešitele a provozní heuristiky. Tyto přístupy slouží jako základ pro zlepšování procesů. Avšak, jejich výkon lze dále zlepšit pomocí moderní výpočtové inteligence. Účelem této práce je tudíž aplikace pokročilých technik umělé inteligence a strojového učení za účelem zlepšování procesů v energeticky náročných průmyslových procesech. V této práci je využit přístup, který řeší tento problém simulací průmyslových systémů a přispívá následujícím: (i)Aplikace techniky strojového učení, která zahrnuje jednorázové učení a neuro-evoluci pro modelování a optimalizaci jednotlivých jednotek na základě dat. (ii) Aplikace redukce dimenze (např. Analýza hlavních komponent, autoendkodér) pro vícekriteriální optimalizaci procesu s více jednotkami. (iii) Návrh nového nástroje pro analýzu problematických částí systému za účelem jejich odstranění (bottleneck tree analysis – BOTA). Bylo také navrženo rozšíření nástroje, které umožňuje řešit vícerozměrné problémy pomocí přístupu založeného na datech. (iv) Prokázání účinnosti simulací Monte-Carlo, neuronové sítě a rozhodovacích stromů pro rozhodování při integraci nové technologie procesu do stávajících procesů. (v) Porovnání techniky HTM (Hierarchical Temporal Memory) a duální optimalizace s několika prediktivními nástroji pro podporu managementu provozu v reálném čase. (vi) Implementace umělé neuronové sítě v rámci rozhraní pro konvenční procesní graf (P-graf). (vii) Zdůraznění budoucnosti umělé inteligence a procesního inženýrství v biosystémech prostřednictvím komerčně založeného paradigmatu multi-omics.
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GABLER, Alain. "On the macroeconomics of firm entry and exit." Doctoral thesis, 2007. http://hdl.handle.net/1814/10690.
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Defence date: 23 November 2007Examining Board: Prof. Omar Licandro, (EUI) ; Prof. Salvador Ortigueira, (EUI) ; Prof. Fabrizio Zilibotti, (University of Zurich) ; Prof. Hugo Hopenhayn, (UCLA)
PDF of thesis uploaded from the Library digital archive of EUI PhD theses
This thesis straddles two seemingly quite distinct fields within macroeconomics, namely endogenous growth and business cycle theory. The unifying element of the thesis is the fundamental role played by firm entry and exit in each chapter. In the longrun, I find that if entering firms imitate incumbents, firm turnover promotes growth by removing inefficient firms and replacing them by more productive ones. In the shortrun, fluctuations in the number of firms lead to movements in sectoral relative prices. In particular, pro-cyclical net entry leads to a fall in the price of investment in terms of consumption goods during booms; those relative price movements may be delayed if it takes time to set up a firm. The first chapter deals with the long-run effects of firm turnover. I set up a dynamic general equilibrium model with firm-specific productivity shocks. Those firms whose productivity has fallen too low exit, and entrants’ expected productivity is a function of current average productivity. Because of the resulting selection and imitation process (similar in some ways to the concept of natural selection), aggregate productivity in the economy grows endogenously. When calibrated to U.S. data, the model suggests that around one-fifth of productivity growth is due to such a selection effect. The following two chapters deal with the short-run effects of net firm entry within a framework of imperfect competition. I argue that the counter-cyclical fluctuations in the price of investment in terms of consumption goods which are observed for the U.S. are due to pro-cyclical competitive pressure through variations in the number of firms. The idea is that, since investment is much more variable than consumption, competition will be more variable in the investment sector, thereby pushing down prices more strongly in the latter sector during expansions.
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Pinho, Bernardo Almeida. "The global airline industry: an assessment of the impact of low-cost carriers on the technical efficiency of full-service airlines." Master's thesis, 2017. http://hdl.handle.net/10071/15785.
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Since the emergence of the first low-fare airline, Southwest Airlines, we have
witnessed the spread of the low-cost phenomenon in different regions of the world. The
simplicity, the low fares and the focus on core business (flying) have been the critical
basis for their success, and the concern of traditional operators who see their market
positioning threatened. To remain competitive, full-service operators have been forced to
redefine their business model.
With great interest in the innovative nature of low-cost carriers, literature has
covered inter-business model comparisons of efficiency, as well as on the analysis of the
strategies carried out by full-service to adapting to the increased competition. However,
there seems to be no study on the impact of low-cost operators on the technical efficiency
of full-service airlines. Thus, this thesis aims to analyse the impact of the low-cost
regional market share on the technical efficiency of full-service airlines domiciled in the
same region. In order to pursue this analysis, a two-stage Data Envelopment Analysis was
implemented. Initially, bootstrapped efficiency scores were estimated for a set of 137
passenger airlines. Subsequently, the estimated efficiency measures were used as a
dependent variable in a truncated bootstrap regression to identify the determinants of the
technical efficiency. Results suggest that larger low-cost market shares are associated
with lower input uses for the same full-service carriers’ output levels based on that region.
This relationship might be explained by the adoption of better management practices that
approach the full-service model to the low-cost model.A criação da primeira companhia aérea de baixo-custo, a "Southwest Airlines", impulsionou o desenvolvimento mundial de tantas outras no sector da aviação. A simplicidade, os preços baixos e o foco no principal objetivo da atividade (voar) têm sido a chave do seu sucesso e, simultaneamente, uma ameaça às companhias aéreas tradicionais. Inevitavelmente, os operadores de serviço-completo têm vindo a realizar mudanças no seu modelo de negócio para conseguirem manter-se competitivas. Recentemente, alguns estudos têm-se focado na comparação entre os dois modelos de negócio e na análise das estratégias das transportadoras tradicionais ao aumento concorrencial. No entanto, parece não existir qualquer investigação acerca do impacto dos operadores de baixo-custo na eficiência técnica dos tradicionais. Assim, este estudo foca-se na relação entre a quota de mercado regional das transportadoras de baixo-custo e a eficiência técnica das companhias aéreas tradicionais sediadas nessa região. Para prosseguir esta investigação, foi implementada uma Análise por Envoltória de Dados de duas etapas. Inicialmente, foram estimadas as pontuações de eficiência técnica com métodos de "bootstrap" para 137 transportadoras de passageiros e, posteriormente, as pontuações foram usadas como variável dependente numa regressão "bootstrapped" truncada para identificar as fontes de eficiência. Os resultados sugerem que uma maior concentração de operadores de baixo-custo numa dada região está associada a uma menor utilização de recursos, por parte dos operadores tradicionais dessa região, para o mesmo nível de produção. Esta relação poderá ser explicada por práticas de gestão mais adequadas que aproximam o modelo tradicional do modelo de baixo-custo.
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Yu, Chunyan. "A comparative study of alternative methods for efficiency measurement with applications to the transportation industry." Thesis, 1995. http://hdl.handle.net/2429/8829.
Full textAbstract:
This thesis is concerned with measuring and explaining the productive efficiency of
firms or organizations. In particular, the study compares three alternative methods of
measuring efficiency, namely, the deterministic frontier method, the stochastic frontier
method, and the data envelopment analysis method (DEA).
The dissertation consists of two parts. In Part I, the relative merits of the three
methods are discussed and evaluated through a Monte Carlo study under certain known
conditions. The study focuses on the effects of exogenous variables on efficiency estimates.
The results show that the stochastic frontier method generally produces better efficiency
estimates than the other two methods. The DEA, however, has a slight advantage in cases
where there are weak input substitution and large variations in input variables. In Part II,
the three methods are examined empirically through their applications to a panel of 19
railways in OECD countries and a panel of 36 international airlines. Comparison of the
three sets of efficiency estimates confirms that on average the stochastic frontier method
yields higher efficiency estimates than the other two methods, as indicated by the Monte
Carlo results. The efficiency estimates by the two parametric methods are highly correlated,
whereas there are considerable differences between the DEA estimates and those from the
parametric methods. This is also consistent with the Monte Carlo results. By comparing the
alternative efficiency estimates in the two applications, it is found that there is less
discrepancy among the three sets of efficiency estimates in the airline case than in the
railway case. This can be partly attributed to the fact that there are fewer variations in the operating environments in the airline case than in the railway case.
The simulation results in Part I provide some general guidelines regarding the relative
merits of the three alternative methods under certain known conditions. The two applications
of the three methods in Part II serve as examples of how these three methods can be applied
to practical problems where no a priori knowledge of either the production technology nor
the efficiency profile exists. They illustrate some of the problems that may be encountered
in empirical applications.
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Jayan, M. V. "Modeling Of Dust Loaded Electrical Characteristics And Collection Efficiency Of Industrial Electrostatic Precipitators." Thesis, 2009. http://hdl.handle.net/2005/965.
Full textAbstract:
With the increase in population and industrial growth, the need for power has increased manifold. A major share of India’s power generation is coal-based generation. Thermal power generation through coal combustion produces minute particles of ash that causes serious environmental problems. Most of the thermal power stations in India use bituminous coal and produce large quantities of fly ash. Fly ash is produced primarily by thermal power plants and, to a lesser extent, by cement and steel plants and railways. This poses problems in the form of land use, health hazards, and environmental dangers.
Today the fly ash from thermal power plants is utilized to make cement. Cement industry needs fly ash with more fine particles. If these fine particles (of diameter in micro-meter range) are left out to atmosphere, it will be easily breathed into lungs, creating health hazard to human as well as animal life. If properly collected, it forms a valuable by product. Hence collecting fly ash is important to reduce pollution and also to increase revenue. Even though there are many devices like cyclones, fabric filters etc. the Electrostatic Precipitator (ESP) is the most efficient device to capture the fly ash.
It is at this juncture a need for such a simple ESP model was felt to facilitate prediction of the V-I characteristics of dust loaded precipitators, be it cement dust or fly ash. Given the fact that 99% of Indian ESPs are operated under DC energization and most of them are running inefficiently due to lack of proper diagnostic tools and also due to lack of interest to invest on an ESP. In such circumstances, the free availability of a simple model that combines the V-I curves with collection efficiency serves to improve the ESP performance in our Indian industries.
In an ESP Voltage-Current (V-I) characteristics are used to diagnose any electrical problems occurring in it. Mathematical model of V-I characteristics under clean air and dust laden conditions will be helpful in diagnosing the ESP problems as well as in designing the ESP. The model will also indirectly reflect upon the collection efficiency of the ESP. The collection efficiency should be as high as possible not only to prevent pollution but also to collect maximum fly ash which is a valuable by-product. The modeling of collection efficiency will help the industries to design a new precipitator as well as to improve the performance the collection efficiency to meet the changing restrictions set by the government to reduce pollution.
In this thesis a mathematical model of ESP based on Finite Difference Method is developed. The modeling is done in three sections.
1. Simulation of clean air V-I characteristics.
2. Simulation of dust laden V-I characteristics.
3. Simulation of collection efficiency.
Simulation of clean air V-I characteristics is done by iteratively solving the Poisson’s equation and current continuity equation, using FDM in one quarter region of the ESP. Just by introducing the effect of particle charge into this solution the dust laden V-I characteristics are simulated. Finally, the collection efficiency is calculated using average charge density at the plates obtained from the above solution.
The developed model is validated at first against published experimental and simulated data and then, with the data obtained through conduction of experiments, by the author, on commercial precipitators situated at a thermal power station and a cement plant, in India. The thesis discusses in detail these theoretical and experimental studies.
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Zelenyuk, Valentin. "New non-parametric efficiency measures : an application to the U.S. brewing industry." Thesis, 1999. http://hdl.handle.net/1957/33269.
Full textAbstract:
This study focuses on the development of new, non-parametric efficiency measures based on the idea of aggregation via merging functions. We use Shephard's (1970) axiomatic approach of distance functions as the basis for theoretical methodology. In particular, this approach is a background for non-parametric efficiency measures defined on a linearly approximated technology set (Farrell, 1957 and Charnes, et al. 1987, and Fare and Grosskopf, 1985).
Two new concerns are discussed: the ambiguity in Farrell efficiency measures and the inconsistency of aggregated Industry efficiency measures with constant returns to scale assumption. As a result, two types of new measures (based on the idea of aggregation) are developed: the average efficiency measures (that take into account both input and output oriented efficiency information) and the industry structural efficiency measures via Geometric Aggregation. The existing efficiency measures as well as newly introduced measures are applied to a sample of U.S. brewing industry. The data supports the importance of new measures and the obtained results are consistent with previous studies that use similar and different (e.g., parametric) approaches.Graduation date: 2000
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(6918713), Somnath Das. "ESSAYS ON INDUSTRIAL ORGANIZATION." Thesis, 2019.
Find full textAbstract:
My dissertation consists of three chapters. In the first chapter, I analyze theeffect of the merger between American Airlines (AA) & US Airways (US) on market price and product quality. I use two complementary methodologies: difference-in-differences (DID) and merger simulation. Contrary to other results in the airline literature, the DID analysis shows that, overall, price has decreased as a result of themerger. While divestitures required as part of the merger had a strong price-reducing effect, the overall decrease involves non-divestiture markets as well. Interestingly, the decrease appears only in large airport-pair markets, whereas prices rose considerably in smaller ones. Effects on quality are mixed. The DID analysis shows that the merger reduced flight cancellations, increased flight delays, and had no effect on flight frequency or capacity overall. Using merger simulation, I find that the change in ownership leads to a 3% increase in price. The structural model performs betterin predicting the post-merger price if I allow the model to deviate from the Bertrand-Nash conduct. A 10% cost reduction due to the merger is able to predict the post-merger price quite well. When I incorporate a conduct parameter into the model, the required percentage of cost savings is lower. Given the divestiture and the subsequententry of low-cost carriers (LCCs), tacit collusion may break down. Thus both cost savings and reduced cooperation could explain a reduction in the price in the post-merger period.In my second chapter, I analyze possible reasons why airline prices are higher inthe smaller markets compared to larger markets. In the literature, most of the studies ignore the fact that the smaller markets are different compared to larger markets in terms of the nature of competition. I find that a combination of lower competition, and lack of entry from low cost carriers (LCCs) are the reasons behind higher prices in the smaller city-pair markets. I show that price is substantially higher in a market with a fewer number of firms controlling for several other factors. My paper estimates the modified critical number of firms to be 5 and the critical value of the HHI to be .6.
In my third chapter, I study the effect of announcement of investment in research & development (R&D) on the value of a firm in the pharmaceutical industry. Three types of R&D by the pharmaceutical firms are considered for the analysis: acquisition of other smaller firms, internal investment in R&D, and collaborative investment in R&D. This chapter finds that few target specific characteristics and financial charac-teristics of the acquiring firm are important drivers of the abnormal returns around the announcement period.
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Zhu, Jiayan. "China's insurance companies' efficiency: an empirical study." Doctoral thesis, 2019. http://hdl.handle.net/10071/21344.
Full textAbstract:
Great achievements have been seen in
China's insurance industry in the past 20 years, however, inefficiency problems were prevailing as many insurance company only pursuing the expansion of the quantity, but not the increase of their key competitiveness. How to improve the core competitiveness of China's insurance industry, especially the efficiency of Chinese-funded insurance companies, has always been an important issue that the Chinese government, regulators and insurance institutions have been paying attention to and exploring for a long time.
This thesis uses the most advanced efficiency evaluation model - three-stage DEA method and a samples of 43 property insurance companies and 53 life insurance companies to calculate the technical efficiency, pure technical efficiency and scale efficiency from 2008 to 2011. The research results show that China’s insurance industry has high technical efficiency and pure technical efficiency, while its scale efficiency is low and its scale is still in an expanding stage from 2008 to 2011. In order to compete with foreign insurance companies, Chinese insurance companies must upgrade their key competitiveness and pure technical efficiency as soon as possible. Through more rational allocation of resources and more refined management, China's insurance industry can achieve its development goals.
According to Empirical research, the main reason for the weak core competitiveness of Chinese small and medium-sized insurance companies is the imbalance of inputs and outputs. Therefore, through rational allocation of resources, optimization of business strategies, and control of costs, the efficiency of companies can be improved.
By studying the factors affecting the efficiency of Chinese insurance companies, the conclusion shows that the expansion of asset size will significantly increase the technical efficiency and scale efficiency of life insurance companies and property insurance companies. Moreover, all efficiency of foreign property insurance companies outperform Chinese-funded ones, while technical efficiency of Chinese-funded life insurance companies outperform foreign ones.Tem-se assistido nos últimos 20 anos um desenvolvimento extraordinário da indústria de seguros na China, contudo, o problema da ineficiência continua a ser um problema grave porquanto que a indústria de seguros na China caracteriza-se no essencial pela expansão em dimensão e não nos fatores de competitividade. A necessidade de melhoria da capacidade competitiva da indústria chinesa de seguros e, em especial, a eficiência de seguradoras de capital chinês tem sido uma preocupação importante para o governo chinês, para os reguladores e para as próprias instituições seguradoras. Este trabalho, utilizando o método de eficiência DEA de três estádios e uma amostra composta por 43 seguradoras de seguros imobiliários e 53 outras do ramo vida, computou a eficiência técnica, eficiência técnica pura e a escala de eficiência no período de 2008 e 2011. Os resultados da investigação mostram que a indústria seguradora da China tem uma elevada eficiência técnica e técnica pura, enquanto que a escala de eficiência é baixa e demonstramos que se encontrava numa fase de desenvolvimento no período de 2008 e 2011. De acordo com a nossa investigação empírica, a razão principal da fraca competitividade das seguradoras chinesas de pequena e média dimensão é o desequilíbrio entre «inputs» e «outputs». Com uma afetação racional de recursos, otimização de estratégias de mercados e controlo de custos, a eficiência das seguradoras poderia ser melhorada. Na análise de fatores que afetam a eficiência das empresas chinesas de seguros, o nosso estudo mostra que o reforço de ativos contribuirá para a melhoria da eficiência técnica e da escala de eficiência de seguradoras tanto do ramo vida como do ramo imobiliário. Concluímos ainda que as seguradoras estrangeiras têm melhor eficiência do que as congéneres chinesas, mas avaliando pela ótica de eficiência técnica, as seguradoras chinesas têm melhor desempenho que as seguradoras estrangeiras.
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Olanrewaju, Oludolapo Akanni. "Analysis and development of an integrated model for assessment of the energy efficiency potential in the industrial sector." 2013. http://encore.tut.ac.za/iii/cpro/DigitalItemViewPage.external?sp=1001030.
Full textAbstract:
D. Tech. Industrial Engineering.Discusses purpose of this study is to derive a new model capable of advanced diagnosis and analysis of energy usage to determine the possible energy efficiency potential through the following in a single model: Analysis of industrial historical data; Prediction of the industrial energy baseline; Computation of the industrial energy efficiency; and Optimization of the industrial energy consumption usage. In this context, the development of a new model involves: Carrying out literature survey; Carrying out Mathematical Analysis of the dynamics of energy efficiency in an industry; Critically analyzing and testing existing models; Evolve a new and novel model; Test the model using data from specific industry; Apply the model to eleven industrial sectors in South Africa. This thesis on energy efficiency potential will be a milestone for different stakeholders, policymakers and decision makers in the energy sector at national and international levels who are, or will be interested in reducing energy input and still produce the observed output levels, by becoming technically efficient. The approach adopted by the study is the integration of Index Decomposition Analysis (IDA), Artificial Neural Network (ANN) and Data Envelopment Analysis (DEA) into a single model.This methodology combines modeling, which is at the core of an energy-management technique, with a wider interpretation of activity growth, structure and efficiency changes which contribute to changes in energy consumption.
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Aikenhead, Graham Smith. "Application of Quantitative and Qualitative Methods for Building a Case for Industrial Pollution Prevention: Case Study of a Dairy Processing Facility." Thesis, 2013. http://hdl.handle.net/10214/5297.
Full textAbstract:
This thesis investigates the use of a combined set of quantitative and qualitative tools to help address known barriers associated with adopting and sustaining pollution prevention (P2) in an industrial manufacturing setting. The research was conducted at an Ontario dairy processing facility in the form of a case study. P2 is an alternative approach to traditional pollution control or abatement techniques. P2 is a preferred method for pollution management, both environmentally and economically, as it focuses on the efficient use of resources to prevent pollution at the source. The tools used in this research included: wastewater treatability testing, hierarchical process mapping, employee interviews, and causal loop diagrams (CLDs). The application of these tools assisted the participating facility in better characterizing its existing environmental problems, uncovering concrete resource saving opportunities within its processes, and providing more adaptive visual approaches of documenting and conveying P2 concepts.OMAFRA Agri-Food and Rural Link KTT Funding Program
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Lima, Gonçalo da Silva. "Efficiency in school education: a semi-parametric study of shool efficiency in OECD countries." Master's thesis, 2017. http://hdl.handle.net/10071/16122.
Full textAbstract:
Efciency-driven reforms have become increasingly relevant in education policy, as education systems face tighter budget constraints. Educational authorities around the world often struggle to foster the best student outcomes out of the set of available school resources. This dissertation aims to contribute to this debate by using a semi-parametric approach to evaluate the efciency across 34 OECD countries, using data from PISA 2015.
The estimation of the education production possibilities frontier is made through a free disposal hull (FDH) method, a non-convex and non-parametric estimator, also extending the analysis to incorporate recently developed partial frontier methods (order-m and order-x).According to the different specifications, ineficient schools could have increased average student achievement between 9%-18%, for the same level of human and material resources, and given the socio-economic characteristics of their students. Differences in
eficiency scores are also investigated. The results suggest that schools that enrol a larger number of students and where the principal can decide on budget allocations are more eficient. On the other hand, schools with high concentration of students from immigrant backgrounds and more repeaters are hindered in the provision of eficient allocations of school resources. Finally, no necessary trade-off is found between efciency and equity in the provision of quality education.Reformas tendo em vista aumentos de eficiência têm-se tornado crescentemente relevantes na definição de políticas educativas, especialmente no contexto de orçamentos educativos mais limitados. Neste sentido, responsáveis em diferentes sistemas educativos têm tentado saber como melhorar os resultados dos alunos, dados os recursos escolares disponíveis. Esta dissertação tem por objectivo contribuir para este debate, através de uma avaliação semi-paramétrica de eficiência escolar em 34 países da OCDE, recorrendo a dados do PISA 2015. Estimamos a fronteira de possibilidades de produção educativa através de "free disposal hull" (FDH), um estimador não-paramétrico e não-convexo. Também estendemos a análise para incorporar métodos de fronteiras parciais (order-m e order-x). De acordo com as diferentes especificações, as escolas ineficientes na amostra poderiam ter aumentado a qualidade de educação entre 9% e 18%, utilizando o mesmo nível de recursos humanos e materiais, e tendo em conta as características socio-económicas dos seus alunos. A variação nos scores de eficiência é também investigada. Os resultados sugerem que escolas com um maior número de alunos e em que o diretor tem poder de decisão sobre a alocação do orçamento escolar são mais efcientes. Por outro lado, escolas com maior concentração de alunos de contextos familiares de imigração e com mais repetentes têm maior difculdade em se aproximar da fronteira internacional de efciência. Por fm, não há evidência de um trade-off necessário entre efciência e equidade na provisão de educação de qualidade.
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Galli, Giovanni. "Packaging waste management: Financial support and cost efficiency in Portugal and Italy." Master's thesis, 2018. http://hdl.handle.net/10071/18709.
Full textAbstract:
The dissertation focuses on the topic of packaging waste management and treats the subject from two different approaches. From a qualitative point of view, it aims to compare the compliance schemes implemented in Portugal and Italy and the model of calculation of the financial support to local authorities. Moreover, from a quantitative point of view, it aims to evaluate the relative cost efficiencies, in both its time invariant and time varying components, by means of stochastic frontier analysis. Regarding the first objective, the main difference between the financial transfers to the local authorities are the presence, in Portugal, of a factor evaluating the quality of the service; while, in Italy, the implementation of a progressive financial compensation, based on different bands for the quality of the waste collected. Furthermore, in the second part, a deterministic time invariant persistent cost efficiency and a stochastic time varying residual cost efficiency are estimated from two panel data, one for each country. The results obtained for the Portuguese system show a little impact of time varying inefficiencies and set the sector on an overall cost efficiency which is half the score of the most efficient firm in the panel. For Italy, the analysis detected a higher impact of time varying factors on the overall cost efficiency of the sector, which, on average, is about one third of the efficiency of the best entities.A presente dissertação discute a gestão de resíduos de embalagens e analisa o tema a partir de duas abordagens diferentes. Do ponto de vista qualitativo, visa comparar os esquemas de conformidade implementados em Portugal e na Itália, e o modelo de cálculo do apoio financeiro às autoridades locais. Além disso, sob ponto de vista quantitativo, pretende-se avaliar as eficiências de custo relativas, nas suas componentes variantes e invariante no tempo, por meio da análise de fronteira estocástica. Em relação ao primeiro objetivo, as principais diferenças entre as transferências financeiras para as autarquias locais são a presença, em Portugal, de um fator de avaliação da qualidade do serviço; enquanto, em Itália, existe a implementação de uma compensação financeira progressiva, baseada em faixas diferentes para a qualidade dos resíduos coletados. No que respeita à segunda parte, uma eficiência determinística de custo persistente e invariável no tempo e uma eficiência residual estocática de custo, e variável no tempo, estimadas a partir de dois panel data, um para cada país. Os resultados obtidos para o sistema português mostram um pequeno impacto de ineficiências variáveis no tempo, e definem o setor com uma eficiência de custo geral que é metade do score apresentado pela empresa mais eficiente no panel. No que concerne a Itália, a análise detetou um impacto maior dos fatores variáveis no tempo na eficiência geral de custo do setor, que, em média, é cerca de um terço da eficiência da melhor entitade.
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Lourenço, Marta Filipa Cardoso. "Planning the delivery of home social services: a mathematical programming-based approach to support routing and scheduling assignments." Master's thesis, 2020. http://hdl.handle.net/10071/21864.
Full textAbstract:
The increased average lifespan, together with low birth rates, are transforming the European Union's
age pyramid. Currently, we are experiencing a transition towards a much older population structure.
Given that the institutions that provide care to these population groups are limited by budgetary
constraints, it is imperative to optimize several processes, among which route planning and staff
scheduling stand out.
This dissertation aims to develop a mathematical programming model to support the planning of routes
and human resources for providers of Home Social Services. Beyond general Vehicle Routing Problems
assumptions, the proposed model also considers the following features: i) working time regulations, ii)
mandatory breaks, iii) users' autonomy, and iii) meals' distribution. The present model, implemented
using GAMS software, focuses simultaneously on two objective functions: minimization of operating
costs, and maximization of equity through the minimization of differences in teams' working times.
Chebyshev's method was chosen to solve the developed multiobjective model.
The model was built based on a Portuguese Private Institution of Social Solidarity. Through the
application of the model, significant improvements are obtained when compared to the current planning
of the partner institution, such as it is the case of an improved workload distribution between caregivers
and routes that will result in lower costs for the institution. This model is fully enforceable to other
institutions that provide services similar or equal to the institution used as a reference.O aumento da esperança média de vida, juntamente com baixas taxas de natalidade, estão a transformar a pirâmide etária da União Europeia. Atualmente, estamos a vivenciar uma transição direcionada para uma estrutura populacional muito mais envelhecida. Dado que as instituições que prestam cuidados a esta fração se encontram limitadas por restrições orçamentais, torna-se imperativo otimizar vários processos, dos quais se destacam planeamento de rotas e escalonamento de funcionárias. Esta dissertação visa introduzir um modelo de programação matemática com a finalidade de apoiar o planeamento de rotas e recursos humanos para prestadores de Serviços de Apoio Domiciliário. O modelo assenta, além dos pressupostos de um "Vehicle Routing Problem", nos seguintes: i) regulações de tempo de trabalho, ii) pausas obrigatórias, iii) autonomia dos utentes, e iv) distribuição de refeições. O modelo, desenvolvido através de software GAMS, foca-se em duas funções objetivo, simultaneamente: minimização dos custos operacionais, e maximização da equidade, através da minimização das diferenças nos tempos de trabalho das equipas. O método de Chebyshev foi o escolhido para desenvolver o modelo multiobjetivo. O modelo foi construído tendo por base uma Instituição Particular de Solidariedade Social em Portugal. Através da aplicação do modelo, obtêm-se melhorias significativas, quando comparado com o atual planeamento da instituição parceira, como é o caso de uma melhor distribuição da carga de trabalho entre as funcionárias e das rotas que resultam da redução dos custos operacionais da instituição. Este modelo é totalmente extensível a outras instituições que prestem serviços semelhantes ou iguais à instituição utilizada como referência.
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Davidson, Gina Monique. "The relationship between organisational culture and financial performance in a South African investment bank." Diss., 2003. http://hdl.handle.net/10500/996.
Full textAbstract:
This research explores the relationship between the organisational culture and financial performance of a South African investment bank by means of quantitative research. The Denison Organizational Culture Survey was used to measure the organisational culture of the investment bank and was administered to a sample of 327 employees. Income statement ratio analysis was selected as a means to assess the financial performance. The results indicate that very few of the financial measures selected could be shown to be correlated with the organisational cultural traits or subscales. Correlations between the cultural dimensions of team orientation, agreement, customer focus and vision were found with certain financial measures. Although these correlations were above the 0.50 level, the levels of significance were not sufficient in all cases to draw conclusions with confidence. The only cultural trait that was found to be correlated with financial measures was the consistency trait.Industrial and Organisational Psychology
M.Com. (Industrial and Organisational Psychology)
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Hoeu, Kim Phei-Linn. "Meating point, the development of a new culinary concept in Bordeaux." Master's thesis, 2019. http://hdl.handle.net/10071/19504.
Full textAbstract:
This paper presents the development of an innovative business plan with the creation of a new restaurant concept in Bordeaux, France. The purpose is to offer a new concept that does not exist in Bordeaux yet: cooking meat of fish on individual sizzling volcanic rocks. Located in the heart of Bordeaux, the restaurant, called Meating Point, aims to propose a memorable experience from the food to the service quality and general atmosphere. Regarding the food and drinks, all the products used are fresh and of high quality, and most of them local and seasonal. Meating point does its best to support local businesses and reduce its CO² emissions.
To assess the industry, a market analysis was built to better understand its business environment. Then, to know if this project entices people and is viable, a survey was conducted on 100 participants worldwide. 64% of the respondents were interested to highly interested in this project and showed great enthusiasm.
To attract and retain customers, the establishment of a virtual presence is necessary with a website and social media fan pages such as Facebook and Instagram in order to interact with customers and followers.
Additionally, the prices offered are within the spending range of the participants. By having control over the production costs, it is possible to operate a high margin to cover the initial investments. With a weekly occupancy of 91%, the breakeven point is reached in only 29 weeks, which means that from this point Meating Point is profitable.Este trabalho apresenta o desenvolvimento de um plano de negócios inovador com a criação de um novo conceito de restaurante em Bordeaux, em França. O objetivo é oferecer um novo conceito que ainda não existe em Bordeaux: cozinhar carne de peixe em rochas vulcânicas escaldantes individuais. Localizado no coração de Bordeaux, o restaurante, chamado Meating Point, tem como objetivo de propor uma experiência memorável desde a comida até a qualidade do serviço e a atmosfera geral. Em relação aos alimentos e bebidas, todos os produtos utilizados são frescos e de alta qualidade, sendo a maioria local e sazonal. O ponto de aquecimento faz o melhor possível para apoiar os negócios locais e reduzir as suas emissões de CO². Para avaliar a indústria, uma análise de mercado foi construída para perceber melhor o seu ambiente de negócios. Então, para saber se este projeto irá atrair pessoas e se for viável, uma pesquisa foi realizada com 100 participantes em todo o mundo. 64% dos entrevistados estavam interessados no projeto e demonstraram grande entusiasmo. Para atrair e reter clientes, o estabelecimento de uma presença virtual é necessário com um site e páginas de fãs de mídia social, como Facebook e Instagram, para interagir com clientes e seguidores. Além disso, os preços oferecidos estão dentro do intervalo de gastos dos participantes. Para ter o controle sobre os custos de produção, é possível operar uma margem alta para cobrir os investimentos iniciais. Com uma ocupação semanal de 91%, o ponto de equilíbrio seria alcançado em apenas 29 semanas, o que significa que, a partir deste ponto, o Ponto de Concentração é lucrativo.
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Oliveira, Adriano Dinis. "Utilização de veículos com multi-compartimentos na definição de rotas de recolha de resíduos recicláveis." Master's thesis, 2014. http://hdl.handle.net/10071/8958.
Full textAbstract:
The concern about collecting and treating recyclable waste has been growing in Portugal since the 90's.
Vehicle routing problems has a key role in companies with the mission to collect and treat waste, since it represents between 66-69 % of the total costs.
The goal of this project is to study a routing problem which uses vehicles with multi-compartments.
This project was developed using data from Valorsul, a company responsible for collecting waste in the surrounding areas of Lisbon.
In this project it is developed a heuristic, cluster-first route-second, and it is made a comparison with the solution used by Valorsul, which uses vehicles with only one compartment.
When analysing the results it is seen that the solution found in the study is better than the one used by the company.
MCVRP is a problem that has not yet been studied extensively so we recommend a further research in developing heuristics and metaheuristics, but always comparing with the solutions obtained by the classical problem.A recolha e tratamento de resíduos recicláveis têm sido alvo de uma crescente preocupação em Portugal desde a década de 90. O problema de definição das rotas de recolha tem um papel fulcral nas empresas que têm como objetivo a recolha e tratamento de resíduos, uma vez que atividade de recolha representa entre 66-69 % dos custos totais. Neste contexto, este projeto pretende estudar o problema de definição de rotas de recolha de dois materiais recicláveis (papel/cartão e plástico/metal) com a utilização de veículos com multi-compartimentos, tendo como caso de estudo a realidade da empresa Valorsul. É desenvolvida uma heurística do tipo cluster-first route-second para a resolução deste problema e é feita uma comparação entre as soluções encontradas e a solução utilizada pela empresa que deriva de um problema clássico de definição de rotas em que são utilizados veículos com apenas um compartimento. Os resultados obtidos apontam para que a utilização de veículos com multi-compartimentos reduza a distância total a percorrer, em comparação com a atual utilização de veículos com apenas um compartimento. Sendo o problema de rotas com vários compartimentos um tema ainda muito pouco estudado na literatura recomenda-se que seja feito um maior esforço no desenvolvimento de heurísticas e meta-heurísticas tendo sempre uma abordagem comparativa com o problema de rotas clássico.
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Ferreira, Pedro Miguel das Neves. "Negotiation for the middle east: a comparative study of cultures and the construction of a negotiation framework for portuguese in Kuwait." Master's thesis, 2017. http://hdl.handle.net/10071/15806.
Full textAbstract:
The amount of ambiguity present in real life negotiations is intolerable towards the possibility of
perceiving the negotiation scenario as a competitive and castrating process for one of the party's.
The temptation to find one-size-fits-all prescription of unerring steps towards the negotiation
success, offers this process no more than a romantic character or maybe, one relieving mirage of
the required multiple factors that the negotiation scenario demands. This dissertation’s objective
is based on the identification and analysis of the cultural dimensions that impact specifically,
business negotiations that take place between a Kuwaiti and a Portuguese party in the attempt to
build a negotiation framework for Portuguese professionals negotiating in Kuwait. We used a
multiple case design and analyzed 17 bilateral negotiation situations. The main source of evidence
was in-depth and semi-structured interviews and the results are shown in cognitive mapping
format. We adapted the interview script and mind map from Falcão (2008) to collect and interpret
the data and we used the Dimensions of Culture Questionnaire from House, Hanges, Javidan,
Dorfman and Gupta (2004) and grouped the impacting data collection into five blocks:
Preparation, People, Partie, Process, Cultural Perception. We believe that we have made
contributions to the study of the negotiation process and it's cross-cultural influence in Kuwait,
that has one of the world’s fast-growing economies and most powerful currency. There are not
many specific studies available for Kuwait negotiation reality. The size of the sample reflects the
number of Portuguese negotiating in Kuwait but at the same time, limits the study. There are areas
of study to be developed in the future namely, communication (verbal and non-verbal), leadership
(individual and teams) and feedback.A ambiguidade que encontramos presente em negociações na vida real não é compatível com a possibilidade de entender a negociação como um cenário único de competição entre duas partes. A tentação de procurar um receituário infalível de passos a dar em direcção ao sucesso negocial não oferece mais do que um carácter romântico ou uma breve miragem do que o processo negocial exige. O objectivo da presente dissertação prende-se com a identificação e análise das dimensões culturais que influenciam o processo negocial entre uma parte Kuwaitiana e uma parte Portuguesa e a construção de um framework negocial para Portugueses no Kuwait. Utilizámos múltiplos casos de estudo e analisámos 17 situações negociais. Adaptámos o guião de entrevista de Falcão (2008), usámos o questionário de dimensões culturais de House, Hanges, Javidan, Dorfman and Gupta (2004) e conduzimos entrevistas semi-estruturadas. Concretizámos os resultados em mapas mentais dentro de cinco blocos: Preparação, Pessoas, Partes, Processo e Percepção Cultural. Procurámos contribuir para o processo informativo bilateral da negociação no Kuwait, um país que tem uma das mais fortes economias mundiais. Existe pouca investigação específica para a realidade negocial no Kuwait. O tamanho da amostra reflecte o número de Portugueses a realizar negociações no Kuwait mas limita o estudo realizado. Existem áreas de estudo com interesse a desenvolver no futuro nomeadamente, comunicação (verbal e não verbal), liderança (individual e de equipas) e feedback.
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Pereira, Bernardo Maria Marçal Grilo de Sousa. "Forecasting model development and application in the aviation industry." Master's thesis, 2021. http://hdl.handle.net/10071/24949.
Full textAbstract:
Forecasting models have been applied to many industries as a decision-making tool for over 100 years. Their application in the aviation industry benefits a wide variety of stakeholders such as airliners and airport authorities, who use past data to predict demand and passenger choices so that they can better define fares, manage their fleet and make decisions on the airport layout and future expansions, among others.
The main objective of this dissertation is the development of a forecasting model capable of predicting the number of flight movements at Lisbon Airport. The model was based on an autoregressive model, which uses past data in order to forecast future figures. Weekly data regarding the flight movements at Lisbon Airport was the sample for this study, which was processed through RStudio programming software.
Once the Autoregressive Moving Average (ARIMA) models were defined, the forecasting data was created and further tested for accuracy using extant data. The impact of COVID-19 had to be considered in this situation, leading to the breakdown of the original time-series into three different samples. The forecasting models were subsequently created through each of these models.
The results were expressed through the three different models, and since two of them have extant data, meaning an existing sample to compare the predicted data, it was possible to determine the accuracy level. However, these models cannot be applied immediately since the impact of COVID-19 is still present and flights have not resumed normality. Once this normality resumes, the models can be applied.Modelos preditivos têm sido aplicados a variados setores como ferramenta de tomada de decisão há mais de 100 anos. A sua aplicação na indústria aeronáutica beneficia uma ampla variedade de interessados, como companhias aéreas e autoridades aeroportuárias que utilizam dados para prever a procura, definir preços, gerir frotas e tomar decisões relativas ao layout do aeroporto, expansões futuras, entre outros. O principal objetivo desta dissertação é o desenvolvimento de um modelo de previsão capaz de prever o número de movimentos de voos no Aeroporto de Lisboa. O modelo foi baseado num modelo autorregressivo, que utiliza dados passados para prever valores futuros. O Aeroporto de Lisboa foi o objeto escolhido para esta dissertação. Dados semanais relativos aos movimentos aéreos no Aeroporto de Lisboa consistiram na amostra para este estudo, os quais foram processados através do software de programação RStudio. Assim que os modelos Autoregressive Moving Average (ARIMA) foram definidos, os dados de previsão foram criados e testados quanto à precisão usando os dados existentes. O impacto do COVID-19 teve que ser considerado nesta situação, levando à divisão da série temporal original em três amostras diferentes. Os modelos de previsão foram posteriormente criados através de cada um desses modelos. Os resultados foram expressos através dos três modelos, e como dois deles possuem dados existentes para comparação com dados previstos, foi possível determinar o nível de precisão. No entanto, os modelos não podem ser aplicados imediatamente, uma vez que o impacto do COVID-19 ainda está presente e os voos não voltaram à normalidade. Uma vez resumida essa normalidade, os modelos podem ser aplicados.
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Frazão, Ana Pascoal. "Planeamento agregado de produção e distribuição da Secil, S.A: um modelo de optimização em programação linear inteira mista." Master's thesis, 2011. http://hdl.handle.net/10071/4431.
Full textAbstract:
Planear sistemas integrados de produção e distribuição de uma cadeia de abastecimento
tende a ser um processo cuja complexidade cresce com o número de intervenientes e com a
gama de produtos em consideração.
Este projecto consiste no desenvolvimento de um modelo para um problema de
planeamento de produção e distribuição integrado, em que se consideram múltiplos centros de
produção, produtos, centros de expedição, meios de transporte e um único período, tendo
como objectivo determinar o fluxo de produtos ao longo da cadeia que minimize o custo total
associado.
O modelo em Programação Linear Inteira Mista aqui proposto teve como objectivo a
determinação da solução óptima para o planeamento de produção e distribuição de uma
cimenteira portuguesa, a Secil S.A.. Desta forma, pretende-se dar um contributo para a
resolução do problema da determinação do fluxo óptimo de produtos durante o processo de
planeamento logístico da empresa.
Na definição do modelo utilizaram-se 269.507 variáveis, das quais 58.858 são inteiras, e
56.187 restrições. Estas restrições descrevem as principais características da cadeia em
estudo, nomeadamente, as limitações às capacidades de produção, armazenamento,
distribuição e aos meios de transporte disponíveis. Numa primeira fase, foi necessário
identificar as relações existentes entre os vários intervenientes nos sistemas de produção e de
distribuição, bem como as questões de planeamento que o modelo deveria contemplar.
Através da realização de um conjunto de testes computacionais, nos quais se utilizou o
software ILOG CPLEX, concluiu-se que era possível obter, em menos de 10 segundos,
resposta para as questões de planeamento identificadas.Planning integrated production and distribution systems of a supply chain tends to be a process whose complexity increases with both the number of players and the range of products being considered. The aim of this project is to develop a model to solve an integrated production and distribution planning problem in a multi-plant, multi-item, multi-retailer, multimodal transportation and single period logistic environment. This model allows determining the flow of products throughout the chain that minimizes the associated total cost. The proposed mixed integer programming model was developed to find an optimal solution to the production and distribution planning problem in a Portuguese cement company, Secil S.A.. Therefore, it aims to contribute to solving the problem of finding the optimal flow of products during the company logistic planning process. The resulting optimization model is large sized. It contains 269.507 variables, with 58.858 of them being integer, and 56.187 constraints. These constraints describe the relevant characteristics of the chain under study, namely, capacities restrictions on storage, dispatch, production and transportation modes. To define the problem, firstly it was necessary to understand the interaction between the several players in the production and distribution systems, as well as the planning needs, which the model aims to address. The model was solved via IBM ILOG CPLEX software. A set of computational tests were performed and it was possible to conclude that in less than 10 seconds the model is capable of providing answers to the identified planning issues.
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Pinheiro, Tatiana Filipa Dias. "O contributo do turismo para o crescimento da economia portuguesa." Master's thesis, 2012. http://hdl.handle.net/10071/6537.
Full textAbstract:
Esta dissertação tem por objetivo estudar o impacto do turismo no crescimento da economia portuguesa, mais concretamente perceber se o Turismo influencia positivamente o crescimento económico de uma economia como a portuguesa, onde o setor tem bastante expressão. Esta análise baseou-se em dados trimestrais e abrangeu um período compreendido entre o primeiro trimestre de 1996 e o último trimestre de 2011.
Para conseguir alcançar o objetivo pretendido nesta dissertação, foram realizadas análises econométricas, mais especificamente: análise de raízes unitárias, com auxilio dos testes ADF (Dikey-Fuller Aumentado), PP (Phillips Perron) e KPSS (KwiatKowski, Phillips, Schmidt e Shin); análise do comportamento das variáveis através de modelos VAR (Vetores Auto-Regressivos), que incluiram teste de Causalidade à Granger, Funções Impulso Resposta e Decomposição das Variâncias; por fim foi realizada uma análise à Cointegração das séries através de um VECM (Modelo Vetorial de Correção de Erros), mais particularmente recorrendo ao Método de Johansen.
Os resultados obtidos da análise empírica dos testes de raízes unitárias, mostram que as séries são não estacionárias, ou seja, são DSP; pode-se também concluir que não há causalidade quer do PIB para o turismo, quer do turismo para o PIB; e também que as séries são cointegradas.
Após a análise econométrica é possível constatar que o turismo, no período analisado, não foi capaz de explicar o crescimento económico do PIB português. Os testes de causalidade à Granger, as Funções Impulso Resposta, e a análise da Decomposição das Variâncias, indicam que o turismo tem um impacto pouco significativo no PIB no curto prazo. Quanto ao longo prazo o impacto do turismo é um pouco mais significativo, embora ainda com pouca relevância.This thesis aims to study the impact of tourism on the growth of the Portuguese economy. It aims to evaluate if tourism has a positive effect on sustainable economic growth, with particular emphasis on the Portuguese economy. To achieve the desired goal in this thesis were several econometric analysis were done, more specifically: analysis of unit roots, with the aid of ADF tests (Augmented Dikey.Fuller), PP (Phillips Perron) and KPSS (KwiatKowsri-Phillips-Schmidt-Shin); analysis of the behavior of the variables through the VAR (Vector Auto-Regressive), which includes the Granger causality test, Impulse Response Functions and Variance Decomposition, and finally an analysis was performed on the co-integration of the series through VECM (Vector Model Error Correction), particularly using the Johansen method. The results of the empirical analysis of the unit root tests show that the series are not stationary, in other words they are DSP, one can also conclude that there is no causality or GDP for tourism or tourism to GDP, and also the series are co-integrated. After the econometric analysis it is clear that tourism, in the analyzed period, was unable to explain the economic growth of the Portuguese GDP. The Granger causality tests, the Impulse Response Functions and Variance Decomposition analysis, indicate that tourism has a little impact on GDP in the short term. In the long term, the impact of tourism it is a little more significant, although still with little relevance.
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Gan, Yi. "An empirical analysis of the influence of exchange rate and prices on tourism demand." Master's thesis, 2015. http://hdl.handle.net/10071/8971.
Full textAbstract:
The World’s tourism industry has been developing for several years. The global economy grows, and more and more people tend to go travelling not only within their own country but also to foreign countries. Thus, it is relevant to investigate the relationship between macroeconomic indicators and the tourism industry. This thesis considers four models to explain the relationship between the economic environment and the tourism demand. The tourism demand is measured by the inbound visitor’s population and the on-the-ground expenditure, and the economic variables include the exchange rate, relative consumer price index, and the World GDP. The database is an unbalanced panel of 218 countries observed over the period 1995-2012. There is some evidence that the World's wealth, a depreciation of national currency and a decline of relative prices do help boosting the number of arrivals and the correspondent expenditure level. In particular, the World's GDP elasticity of real expenditure level per visitor is about 0.44. The exchange rate is not always positively related to the dependent variable, which is not consistent to previous research. At the same time, the relative prices are always significant in the models and with the expected negative sign.A indústria mundial de turismo tem vindo a desenvolver-se ao longo dos anos. A economia mundial cresce, graças em parte à globalização, e cada vez mais pessoas tendem a viajar não só no seu espaço geográfico mas também para países estrangeiros. Por estas razões torna-se relevante estudar a relação entre as variáveis macroeconómicas fundamentais e a indústria turística. Esta tese considera quatro modelos para explicar a relação entre o enquadramento económico e a procura de turismo. A procura de turismo é medida pelo número de turistas e as despesas por eles efetuadas, e as variáveis económicas incluem a taxa de câmbio, o índice relativo de preços do consumidor, e o PIB mundial. A base de dados é constituída por um painel não equilibrado de 218 países para o período de 1995-2012. Os resultados apontam para a relevância da riqueza mundial, da depreciação da moeda nacional e do declínio nos preços relativos ajudarem a aumentar o número de chegadas e o correspondente nível de despesa por visitante. Em particular, a elasticidade da despesa realizada em turismo em relação ao produto mundial é de cerca de 0.44. A taxa de câmbio nem sempre é positivamente relacionada com as variáveis dependentes, o que não é consistente com os resultados da literatura anterior. Simultaneamente, os preços relativos são sempre significativos nas regressões e com os esperados sinais negativos.