Letteratura scientifica selezionata sul tema "Mathematical models-overhead costs"
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Articoli di riviste sul tema "Mathematical models-overhead costs"
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Bogachkov, I. M., e R. N. Khamitov. "Algorithm to select the voltage class for the gas field electricity supply system". Vestnik IGEU, n. 2 (30 aprile 2021): 32–39. http://dx.doi.org/10.17588/2072-2672.2021.2.032-039.
Testo completoAbstract (sommario):
The current algorithms and mathematical models to select the voltage class based on the theory of experimental planning are developed for industrial enterprises (overhead lines with a length of up to 10 km, a power of up to 20 MV, a radial arrangement with a transformation at the end of the line). They do not consider the features of gas fields (overhead lines with a length of up to 20 km and a capacity of 1 MV with a projected growth of up to 10 MV, a transmission network with one pass-through trunk line with distributed transformation along the line). Currently, to develop a mathematical model, the following factors are considered: the average length of the power line and the total load of an enterprise. The proposed models do not allow us to quantify the dynamics of the gas fields power supply system considering the multiple growth of the electrical load in each period of the life cycle. The purpose of this study is to develop a model to solve this problem. An extreme experiment has been carried out during the research. The following input data are set: the average length of the power line; the number of gas clusters; the growth rate of the electric load. The response function is the voltage class that is optimal for the minimum discounted cost. The authors suggest the regression model. In this model the “total load” factor is split into two components, they are gas clusters and growth rate of electric loads. The algorithm to select the optimal voltage class of a distribution grid is proposed. The dynamic experiment is carried out and the growth rate of electric loads in the regressive model is being changed while other factors are being unchanged. As a result, the optimal minimum of the discounted costs of the voltage class for each period of the field life cycle is obtained. The algorithm is implemented in “PRON” software. With the help of “PRON” software, the distribution grids of several operating gas fields in Western Siberia have been investigated. The optimal voltage class of a distribution grid of gas fields is 20 kV. The reliability of the results is verified by reference models of calculating discounted costs.
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Hamdollahzadeh, Ali, e Kamran Jamali Firouzabadi. "A Model to Determine Optimal Composition of Production to Obtain Maximum Profit & Reduce Overhead Costs by Linear Programming". Modern Applied Science 10, n. 10 (26 settembre 2016): 289. http://dx.doi.org/10.5539/mas.v10n10p289.
Testo completoAbstract (sommario):
There are many factors which put emphasize on the importance of developing pharmaceutical industry such as human health, reduced rate of using medicines, improve healthcare to global level, influence of pharmaceutical industry on exchange market, creating job and etc. Growing improvements in production systems, appearance of mechanized systems and dynamic commercial markets have highlighted the requirements of planning. This study aims to provide a model for defining the optimal composition of production in Sobhan Darou Pharmaceutical Company to obtain maximum profits and reduce overhead costs by linear programming. Lingo application is applied to reach mentioned goals. The results showed that a mathematical planning model can be used to determine minimum of total costs and inventory control strategy. Using linear programming we can take into account all perceptible and imperceptible factors to have a choice, while output models only consider quantitative values. Another advantage of leaner programming is that it can calculate production weight and rate with a systematic method which increases the efficiency and helps to have a proper choice.
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Kovalyov, М. Ya, B. M. Rozin e I. A. Shaternik. "Approach to optimizing charging infrastructure of autonomous trolleybuses for urban routes". Informatics 18, n. 4 (31 dicembre 2021): 79–95. http://dx.doi.org/10.37661/1816-0301-2021-18-4-79-95.
Testo completoAbstract (sommario):
P u r p o s e s. When designing a system of urban electric transport that charges while driving, including autonomous trolleybuses with batteries of increased capacity, it is important to optimize the charging infrastructure for a fleet of such vehicles. The charging infrastructure of the dedicated routes consists of overhead wire sections along the routes and stationary charging stations of a given type at the terminal stops of the routes. It is designed to ensure the movement of trolleybuses and restore the charge of their batteries, consumed in the sections of autonomous running.The aim of the study is to create models and methods for developing cost-effective solutions for charging infrastructure, ensuring the functioning of the autonomous trolleybus fleet, respecting a number of specific conditions. Conditions include ensuring a specified range of autonomous trolleybus running at a given rate of energy consumption on routes, a guaranteed service life of their batteries, as well as preventing the discharge of batteries below a critical level under various operating modes during their service life.M e t ho d s. Methods of set theory, graph theory and linear approximation are used.Re s u l t s. A mathematical model has been developed for the optimization problem of the charging infrastructure of the autonomous trolleybus fleet. The total reduced annual costs for the charging infrastructure are selected as the objective function. The model is formulated as a mathematical programming problem with a quadratic objective function and linear constraints.Co n c l u s i o n. To solve the formulated problem of mathematical programming, standard solvers such as IBM ILOG CPLEX can be used, as well as, taking into account its computational complexity, the heuristic method of "swarm of particles". The solution to the problem is to select the configuration of the location of the overhead wire sections on the routes and the durations of charging the trolleybuses at the terminal stops, which determine the corresponding number of stationary charging stations at these stops.
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Kachanov, A. N., D. A. Korenkov, A. A. Revkov, V. V. Maksimov e O. V. Vorkunov. "Words high-frequency drying processes simulation of wooden tangent towers in a vacuum chamber". Power engineering: research, equipment, technology 22, n. 6 (26 marzo 2021): 130–42. http://dx.doi.org/10.30724/1998-9903-2020-22-6-130-142.
Testo completoAbstract (sommario):
THE PURPOSE. The service life duration of wooden tangent towers used on overhead transmission lines with a voltage of up to 35 kV depends on the quality of lumber drying and subsequent impregnation. The drying of tangent tower workpieces is currently carried out by atmospheric or convective methods and is the longest and one of the energy-consuming stages of their production. At the same time, there are promising electrotechnological drying installations that can reduce the duration and improve drying quality at comparable specific energy costs. Such installations include vacuum high-frequency complexes, the wide introduction of which is complicated by a number of unresolved scientific and technical problems like optimizing vacuum high-frequency drying modes and ensuring electromagnetic field uniformity in long workpieces. The purpose of this article is to obtain mathematical tools that simultaneously describe the cross-effects of electromagnetic phenomena and heat and mass transfer processes in long-sized lumber and contribute to the further solution of these problems. METHODS. The positions of the theory of electromagnetic field, heat mass transfer and heat mass exchange, methods of mathematical modeling were used for this purpose. Also the results of previous studies of electromagnetic field distribution in the cross-section and longitudinal sections of the working chamber loading are taken into account. RESULTS. А one-dimensional mathematical model is obtained. It describes the influence of electromagnetic wave distribution along the length of tangent towers and external medium parameters on the temperature and moisture content in the material. This model is characterized by the possibility of using simple algorithms for analyzing differential equation systems based on the finite differe nce method and requiring less initial data on the drying material properties. CONCLUSION. The obtained by using the proposed model and the method of its analysis the numerical study results are compared with the available experimental data. Based on this comparison it is concluded that the obtained model is adequate and more effective relative to other existing models of vacuum high-frequency drying. Generally, further use of the presented mathematical toolkit to optimize the design and modes of vacuum-high-frequency complexes in the task of drying wooden tangent towers will increase the reliability of overhead transmission lines.
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Elghaish, Faris, M. Reza Hosseini, Saeed Talebi, Sepehr Abrishami, Igor Martek e Michail Kagioglou. "Factors Driving Success of Cost Management Practices in Integrated Project Delivery (IPD)". Sustainability 12, n. 22 (16 novembre 2020): 9539. http://dx.doi.org/10.3390/su12229539.
Testo completoAbstract (sommario):
Integrated project delivery (IPD) is a mode of project procurement recognised as facilitating superior project performance. However, this success is contingent on effective cost management practices that share cost data with all project stakeholders in an accurate, timely and transparent manner. Despite an extensive literature on aspects of cost management, none identifies the essential ingredients required of an effective cost management system, sufficiently robust to support successful IPD projects. Candidate cost management augmenting practices are drawn from the literature, and presented for scrutiny in questionnaire form, to fifty IPD experienced experts, based in the USA, UK and Australia. Findings reveal activity-based costing (ABC) to be effective at identifying overhead costs and creating accounting transparency. Similarly, earned value management (EVM), in combination with ABC, is effective at developing mathematical models for equitable risk-reward distribution. Moreover, web-based management systems, as supported by Building Information Modelling (BIM), are effective at generating trust and collaboration on which IPD success depends. A questionnaire survey using purposive sampling was conducted to assess the factors driving success of implementing IPD regarding cost management process. The contribution to knowledge made by this paper is in identifying requisite support mechanisms essential to elevate traditional cost management practices to the higher standard needed to ensure IPD delivery success.
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Leśniak, Agnieszka. "Statistical Methods in Bidding Decision Support for Construction Companies". Applied Sciences 11, n. 13 (27 giugno 2021): 5973. http://dx.doi.org/10.3390/app11135973.
Testo completoAbstract (sommario):
On the border of two phases of a building life cycle (LC), the programming phase (conception and design) and the execution phase, a contractor is selected. A particularly appropriate method of selecting a contractor for the construction market is the tendering system. It is usually based on quality and price criteria. The latter may involve the price (namely, direct costs connected with works realization as well as mark-ups, mainly overhead costs and profit) or cost (based on the life cycle costing (LCC) method of cost efficiency). A contractor’s decision to participate in a tender and to calculate a tender requires an investment of time and company resources. As this decision is often made in a limited time frame and based on the experience and subjective judgement of the contractor, a number of models have been proposed in the literature to support this process. The present paper proposes the use of statistical classification methods. The response obtained from the classification model is a recommendation to participate or not. A database consisting of historical data was used for the analyses. Two models were proposed: the LOG model—using logit regression and the LDA model—using linear discriminant analysis, which obtain better results. In the construction of the LDA model, the equation of the discriminant function was sought by indicating the statistically significant variables. For this purpose, the backward stepwise method was applied, where initially all input variables were introduced, namely, 15 identified bidding factors, and then in subsequent steps, the least statistically significant variables were removed. Finally, six variables (factors) were identified that significantly discriminate between groups: type of works, contractual conditions, project value, need for work, possible participation of subcontractors, and the degree of difficulty of the works. The model proposed in this paper using a discriminant analysis with six input variables achieved good performance. The results obtained prove that it can be used in practice. It should be emphasized, however, that mathematical models cannot replace the decision-maker’s thought process, but they can increase the effectiveness of the bidding decision.
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Akhmadi, Akhmadi, Etty Siswati e Nurrasyidah Putri. "Studi Komparatif Tingkat Pendapatan Antara Usaha Kelapa dan Pinang pada Perkebunan Rakyat Desa Sungai Beras Kabupaten Tanjab Timur". Eksis: Jurnal Ilmiah Ekonomi dan Bisnis 10, n. 2 (31 gennaio 2020): 68. http://dx.doi.org/10.33087/eksis.v10i2.164.
Testo completoAbstract (sommario):
This type of research is quantitative research that is research using data expressed in numerical form on parts and phenomena and their relationships. This research usually aims to develop and use mathematical models, theories or hypotheses related to natural phenomena. This research is a survey and interview directly to the owners of coconut and areca nut business and records everything that the writer needs in connection with the problem of the writer. In this study using data analysis methods, namely qualitative data analysis. Qualitative data is data in the form of not numbers but with words that can be used to describe, complete and explain and strengthen quantitative data directly in the field. (Sugiyono, 2011: 23). production costs are all costs associated with the goods produced, wherein there are elements of raw material costs, direct labor costs and factory overhead costs. Based on the time period, production can be divided into short-term and long-term. In the short term the company during its production period can add one factor of production while other factors of production are considered constant. This means that some factors of production cannot be added. Whereas in the long run, companies can change or add to all factors of production they use. The initial investment of a coconut plantation business is Rp.37,004,000 which is calculated before the production period of 7 (seven) years and the initial investment of areca nut plantation is Rp.34,750,000 which is calculated before the production period for 4 (four) years, for production costs in one the coconut plantation business year is obtained at Rp.5,600,000 and the production cost of the areca nut business in one year is Rp.108,200,000, the comparison between the coconut plantation business income and the areca nut business revenue is obtained for the income of the coconut plantation business income for one year of Rp. .14,400,000 and the results of areca nut business revenue for one year amounted to Rp. 110,200,000 So, it can be concluded that the biggest income is in the nut business compared to the coconut business.
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Ajjaj, Souad, Souad El Houssaini, Mustapha Hain e Mohammed-Alamine El Houssaini. "Performance Assessment and Modeling of Routing Protocol in Vehicular Ad Hoc Networks Using Statistical Design of Experiments Methodology: A Comprehensive Study". Applied System Innovation 5, n. 1 (2 febbraio 2022): 19. http://dx.doi.org/10.3390/asi5010019.
Testo completoAbstract (sommario):
The performance assessment of routing protocols in vehicular ad hoc networks (VANETs) plays a critical role in testing the efficiency of the routing algorithms before deployment in real conditions. This research introduces the statistical design of experiments (DOE) methodology as an innovative alternative to the one factor at a time (OFAT) approach for the assessment and the modeling of VANET routing protocol performance. In this paper, three design of experiments methods are applied, namely the two-level full factorial method, the Plackett–Burman method and the Taguchi method, and their outcomes are comprehensively compared. The present work considers a case study involving four factors namely: node density, number of connections, black hole and worm hole attacks. Their effects on four measured outputs called responses are simultaneously evaluated: throughput, packet loss ratio, average end-to-end delay and routing overhead of the AODV routing protocol. Further, regression models using the least squares method are generated. First, we compare the main effects of factors resulted from the three DOE methods. Second, we perform analysis of variance (ANOVA) to explore the statistical significance and compare the percentage contributions of each factor. Third, the goodness of fit of regression models is assessed using the adjusted R-squared measure and the fitting plots of measured versus predicted responses. VANET simulations are implemented using the network simulator (NS-3) and the simulator of urban mobility (SUMO). The findings reveal that the design of experiments methodology offers powerful mathematical, graphical and statistical techniques for analyzing and modeling the performance of VANET routing protocols with high accuracy and low costs. The three methods give equivalent results in terms of the main effect and ANOVA analysis. Nonetheless, the Taguchi models show higher predictive accuracy.
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Pereverzyev, K., V. Vasenko e G. Domanska. "The technology of a condition based maintenance of an overhead contact line with Markov approximation of contact wire wear". Lighting engineering and power engineering 1, n. 57 (6 aprile 2020): 3–8. http://dx.doi.org/10.33042/2079-424x-2020-1-57-3-8.
Testo completoAbstract (sommario):
The technologies of OCL condition based maintenance were improved for providing reliable and economic current collecting on electrified railways and in traction power networks of urban electric transport. It is established that one of the most perspective methods of reducing operating costs is the transition to scientifically justified terms of repair and planning of works based on the actual state of OCL, the reliability of which is determined by the reliability, repair suitability and durability of the elements. The basic criteria of the current collecting process are proposed: the value of contacting pair wear, the detachment of the current collectors from the wires, the scope of oscillations of pantograph head and the contact pressure, coefficients of contact unreliability and cost savings of collecting a power from catenary, and, finally, a minimum of annual operating costs. Technology of maintenance according to Markov type parameter control is developed. Models of controlling actions on stagger and the contact wire gradient adjustment processes are developed. The standard linear programming algorithm was used to solve the problem. The application of such technology to determine the matrix of controlling actions based on the results of monitoring the stagger and the contact wire gradient is shown. The factors that determine the cost of staying in a state of stagger have been identified. The controlling actions matrices on the stagger and the contact wire gradient and the cost of staying in these gradient states are established. The technology of service with Markov approximation of wear of contact wires is offered. It has been investigated that the contact wires, primarily due to wear, are degraded during operation. Degradation processes cause gradual failures. The first group of failures: breakages, burnouts, local wear - require controlling actions to incut the insertion or putting into operation a shunt. The second group: a burnout, a decrease in the average cross-section of a wire less than the allowable one requires controlling actions to replace the wire of the entire tension length. After conducting the first type of controlling actions, the contact wire returns to the working state with the previous value of the determining parameter. When performing a second type of controlling actions, the defining parameter returns to its original state. If the quantification step is chosen such that the intensities of failures and transitions from one state to another with a sufficient degree of accuracy were constant, then the graph of states and transitions, as well as the Kolmogorov differential equations, can be used for the research. The readiness function, the density of time distribution of infallible operation, the total failure rate, and the average recovery rate from state S0i to Si are determined. Thus, all reliability indicators are defined and it is possible to use them in determining the condition of the contact wire of the tension length. Experience has shown that the most effective diagnostics of the condition of OCL devices combines the assessment of the state on mathematical, simulation models and measurements with the use of car laboratories for testing the contact network and devices for monitoring the parameters of the contact wire for the railcar. Key words –overhead contact line,contact wire, mainanance technology, controlling action models.
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Ferrucci, Filomena, Pasquale Salza e Federica Sarro. "Using Hadoop MapReduce for Parallel Genetic Algorithms: A Comparison of the Global, Grid and Island Models". Evolutionary Computation 26, n. 4 (dicembre 2018): 535–67. http://dx.doi.org/10.1162/evco_a_00213.
Testo completoAbstract (sommario):
The need to improve the scalability of Genetic Algorithms (GAs) has motivated the research on Parallel Genetic Algorithms (PGAs), and different technologies and approaches have been used. Hadoop MapReduce represents one of the most mature technologies to develop parallel algorithms. Based on the fact that parallel algorithms introduce communication overhead, the aim of the present work is to understand if, and possibly when, the parallel GAs solutions using Hadoop MapReduce show better performance than sequential versions in terms of execution time. Moreover, we are interested in understanding which PGA model can be most effective among the global, grid, and island models. We empirically assessed the performance of these three parallel models with respect to a sequential GA on a software engineering problem, evaluating the execution time and the achieved speedup. We also analysed the behaviour of the parallel models in relation to the overhead produced by the use of Hadoop MapReduce and the GAs' computational effort, which gives a more machine-independent measure of these algorithms. We exploited three problem instances to differentiate the computation load and three cluster configurations based on 2, 4, and 8 parallel nodes. Moreover, we estimated the costs of the execution of the experimentation on a potential cloud infrastructure, based on the pricing of the major commercial cloud providers. The empirical study revealed that the use of PGA based on the island model outperforms the other parallel models and the sequential GA for all the considered instances and clusters. Using 2, 4, and 8 nodes, the island model achieves an average speedup over the three datasets of 1.8, 3.4, and 7.0 times, respectively. Hadoop MapReduce has a set of different constraints that need to be considered during the design and the implementation of parallel algorithms. The overhead of data store (i.e., HDFS) accesses, communication, and latency requires solutions that reduce data store operations. For this reason, the island model is more suitable for PGAs than the global and grid model, also in terms of costs when executed on a commercial cloud provider.
Tesi sul tema "Mathematical models-overhead costs"
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Fechner, Harry H. E., University of Western Sydney, College of Law and Business e School of Management. "Data base accuracy and integrity as a precondition for overhead allocations". THESIS_CLAB_MAN_Fechner_H.xml, 2004. http://handle.uws.edu.au:8081/1959.7/807.
Testo completoAbstract (sommario):
Interest in more accurate assignment of overhead costs to establish credible product/service cost profiles has assumed substantial prominence in much of the recent debates on management accounting practices. While the promotion of new cost management systems and in particular Activity Based Costing (ABC) has promised to address many of the perceived shortcomings of more traditional and long established techniques, the lack of its implementation success raises some concern as to the validity and value of these new system designs. A major purpose of this thesis is the development of a mathematical model that is capable of computing overhead allocations on the basis of organisational specific dimensions other than DLH.While almost all data bases suffer from data entry and omission errors, the information content contained in the data bases often forms the basis for management decisions without first confirming the accuracy of the data base content. The model has been successfully applied and tested to detect internal consistency and data element detail accuracy. Future research may test the applicability of the model with more diverse data bases to confirm its generalisability as an investigative as well as predictive model.Doctor of Philosophy (PhD)
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Fechner, Harry H. E. "Data base accuracy and integrity as a precondition for overhead allocations". Thesis, 2004. http://handle.uws.edu.au:8081/1959.7/807.
Testo completoAbstract (sommario):
Interest in more accurate assignment of overhead costs to establish credible product/service cost profiles has assumed substantial prominence in much of the recent debates on management accounting practices. While the promotion of new cost management systems and in particular Activity Based Costing (ABC) has promised to address many of the perceived shortcomings of more traditional and long established techniques, the lack of its implementation success raises some concern as to the validity and value of these new system designs. A major purpose of this thesis is the development of a mathematical model that is capable of computing overhead allocations on the basis of organisational specific dimensions other than DLH.While almost all data bases suffer from data entry and omission errors, the information content contained in the data bases often forms the basis for management decisions without first confirming the accuracy of the data base content. The model has been successfully applied and tested to detect internal consistency and data element detail accuracy. Future research may test the applicability of the model with more diverse data bases to confirm its generalisability as an investigative as well as predictive model.
Libri sul tema "Mathematical models-overhead costs"
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Abel, Andrew B. The mix and scale of factors with irreversibility and fixed costs of investment. Cambridge, MA: National Bureau of Economic Research, 1997.
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Caballero, Ricardo J. Fixed costs: The demise of marginal q. Cambridge, MA: National Bureau of Economic Research, 1996.
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Miyama, Akira. Nishi Doitsu koteihi riron. Moriyama Shoten, 1987.
Cerca il testo completoAtti di convegni sul tema "Mathematical models-overhead costs"
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Abrahamson, Shaun, David Wallace, Nicola Senin e Nick Borland. "Integrated Engineering, Geometric, and Customer Modeling: LCD Projector Design Case Study". In ASME 1999 Design Engineering Technical Conferences. American Society of Mechanical Engineers, 1999. http://dx.doi.org/10.1115/detc99/cie-9084.
Testo completoAbstract (sommario):
Abstract This paper describes an integrated product design study conducted with Polaroid Corporation for a liquid crystal display video projector, applying a research system called DOME. The services of distributed objects — encapsulating CAE simulations, component catalogs, manufacturing cost models, geometric and configuration models, customer preference models, and environmental life-cycle assessment — are mathematically related to form an integrated product system model. Software objects providing optimization and decision support are also included in the model to create a design tradeoff environment. As such, designers can obtain sales predictions based upon configuration changes and make tradeoffs with other requirements. Benchmarking suggests there would be approximately a 30% increase in the time to fully evaluate the first design configuration due to the overhead of creating the integrated system model. However, the time to fully evaluate subsequent alternatives may be reduced from months to minutes.