• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 1628
  • 703
  • 318
  • 177
  • 169
  • 91
  • 60
  • 48
  • 48
  • 46
  • 44
  • 38
  • 32
  • 30
  • 26
  • Tagged with
  • 4020
  • 740
  • 709
  • 584
  • 510
  • 404
  • 338
  • 324
  • 292
  • 283
  • 270
  • 258
  • 249
  • 248
  • 224
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
191

Integrated high-resolution modelling of domestic electricity demand and low voltage electricity distribution networks

Richardson, Ian January 2011 (has links)
Assessing the impact of domestic low-carbon technologies on the electricity distribution network requires a detailed insight into the operation of networks and the power demands of consumers. When used on a wide-scale, low-carbon technologies, including domestic scale micro-generation, heat pumps, electric vehicles and flexible demand, will change the nature of domestic electricity use. In providing a basis for the quantification of the impact upon distribution networks, this thesis details the construction and use of a high-resolution integrated model that simulates both existing domestic electricity use and low voltage distribution networks. Electricity demand is modelled at the level of individual household appliances and is based upon surveyed occupant time-use data. This approach results in a simulation that exhibits realistic time-variant demand characteristics, in both individual dwellings, as well as, groups of dwellings together. Validation is performed against real domestic electricity use data, measured for this purpose, from dwellings in Loughborough in the East Midlands, UK. The low voltage distribution network is modelled using real network data, and the output of its simulation is validated against measured network voltages and power demands. The integrated model provides a highly detailed insight into the operation of networks at a one-minute resolution. This integrated model is the main output of this research, alongside published articles and a freely downloadable software implementation of the demand model.
192

Stochastic inventory theory and the demand for money

Smith, Gregor W. January 1986 (has links)
This thesis describes an inventory-theoretic approach to the study of the demand for money. It aims to connect money demand theory with optimal inventory theory on the one hand and with time series empirical evidence on the other. Thus it incorporates recent advances in inventory theory and extends these to allow the interest rate to follow a stochastic process. The problem of minimising the expected, discounted suns of cash-management costs is ascribed to an agent. Through the use of continuous-time, stochastic, optimal control an optimal cash-management policy is shown to exist and be of a familiar target-threshold form. Closed-form expressions for the forward-looking time-varying targets and thresholds are derived in special cases. The steady-state, Baumol-Tabin model, a further special case, also is examined in detail. The theory implies that expected future interest rates may influence money holdings despite the absence of strictly convex adjustment costs. A distributed-1ag expression for these holdings is proposed in which the adjustment and expectations dynamics are derived front theory. Aggregation over time and, to a lesser extent, over agents is treated explicitly. The econometric issues involved in testing models of the demand for money with rational expectations are outlined and simulation evidence on the predictions of the theory is provided. The theory gives rise to new predictions concerning expectations effects and variable adjustment speeds. It can also account for the findings of empirical research. In particular, it largely resolves the problem of slow adjustment in empirical money demand equations.
193

Demand for Money in Korea: an Empirical Study

Lee, Yang Seob 08 1900 (has links)
No description available.
194

Stochastic joint replenishment problems : periodic review policies

Alrasheedi, Adel Fahad January 2015 (has links)
Operations Managers of manufacturing systems, distribution systems, and supply chains address lot sizing and scheduling problems as part of their duties. These problems are concerned with decisions related to the size of orders and their schedule. In general, products share or compete for common resources and thus require coordination of their replenishment decisions whether replenishment involves manufacturing operations or not. This research is concerned with joint replenishment problems (JRPs) which are part of multi-item lot sizing and scheduling problems in manufacturing and distribution systems in single echelon/stage systems. The principal purpose of this research is to develop three new periodic review policies for stochastic joint replenishment problem. It also highlights the lack of research on joint replenishment problems with different demand classes (DSJRP). Therefore, periodic review policy is developed for this problem where the inventory system faces different demand classes that are deterministic demand and stochastic demand. Heuristic Algorithms have been developed to obtain (near) optimal parameters for the three policies as well as a heuristic algorithm has been developed for DSJRP. Numerical tests against literature benchmarks have been presented.
195

The modelling of energy efficient drying for DSM

Gilmour, James Ewan January 1999 (has links)
This thesis investigates the modelling of drying processes for the promotion of market-led Demand Side Management (DSM) as applied to the UK Public Electricity Suppliers. A review of DSM in the electricity supply industry is provided, together with a discussion of the relevant drivers supporting market-led DSM and energy services (ES). The potential opportunities for ES in a fully deregulated energy market are outlined. It is suggested that targeted industrial sector energy efficiency schemes offer significant opportunity for long term customer and supplier benefit. On a process level, industrial drying is highlighted as offering significant scope for the application of energy services. Drying is an energy-intensive process used widely throughout industry. The results of an energy survey suggest that 17.7 per cent of total UK industrial energy use derives from drying processes. Comparison with published work indicates that energy use for drying shows an increasing trend against a background of reducing overall industrial energy use. Airless drying is highlighted as offering potential energy saving and production benefits to industry. To this end, a comprehensive review of the novel airless drying technology and its background theory is made. Advantages and disadvantages of airless operation are defined and the limited market penetration of airless drying is identified, as are the key opportunities for energy saving. Limited literature has been found which details the modelling of energy use for airless drying. A review of drying theory and previous modelling work is made in an attempt to model energy consumption for drying processes. The history of drying models is presented as well as a discussion of the different approaches taken and their relative merits. The viability of deriving energy use from empirical drying data is examined. Adaptive neuro fuzzy inference systems (ANFIS) are successfully applied to the modelling of drying rates for 3 drying technologies, namely convective air, heat pump and airless drying. The ANFIS systems are then integrated into a novel energy services model for the prediction of relative drying times, energy cost and atmospheric carbon dioxide emission levels. The author believes that this work constitutes the first to use fuzzy systems for the modelling of drying performance as an energy services approach to DSM. To gain an insight into the 'real world' use of energy for drying, this thesis presents a unique first-order energy audit of every ceramic sanitaryware manufacturing site in the UK. Previously unknown patterns of energy use are highlighted. Supplementary comments on the timing and use of drying systems are also made. The limitations of such large scope energy surveys are discussed.
196

Poptávka českých domácností po potravinách: Koherentní poptávkový systém uvažující selektivitu / Household food demand in the Czech Republic: coherent demand system dealing with selectivity

Smutná, Šarlota January 2016 (has links)
Demand for food is widely studied topic in applied econometrics. Demand systems are the most useful models to evaluate demand and estimate the income and price elasticities. Different demand systems used for food demand are discussed in this thesis. Almost Ideal Demand System (AIDS) is the most popular among researchers thanks to conformity with economic theory, simple estimation, and flexibility with respect to non-linearity of Engel's curves or to control for socio-demographic or structural variables of household. Reporting of zero consumption by respondents when analysing demand on budget survey data requires special treatment, as censoring leads to the selectivity problem and hence biased estimates. Several techniques to treat the selectivity in order to obtain unbiased estimate of demand elasticities are discussed. Specifically, the Heien and Wessels, Shonkwiler and Yen, and Cosslett's semi-parametric corrections are incorporated into the AIDS model and empirically compared among each other. Since homogeneity and symmetry conditions are not fulfilled in this case, income and price elasticities of food demand are estimated by the unrestricted version of QUAIDS model which suits the budget survey data of Czech households the best with the correction for the selectivity by Shonkwiler and Yen's estimator....
197

The platinum market: fundamentals affecting supply and demand

Mauve, Anton Christopher 22 May 2014 (has links)
The platinum market is best understood through a comprehensive analysis of supply and demand. Supply is most significantly affected by production constraints and the erratic draw-down in Russian stockpiles. Total world supply of platinum for 1998 amounted to 5.915 Moz, 64% of which was produced from the Bushveld Complex in South Africa. The remainder emanated from Russia, Zimbabwe, the United States, Canada and the recycling of autocatalysts. Supply is forecast to drop by 320 000 oz in 1999 due to a lower Russian export quota and reduced Zimbabwean production. Demand for platinum is unusual, in that it is sought after both as a store of wealth, and has properties that make it irreplaceable in a host of industrial applications. Current world demand for the metal is driven by a growing Eastern jewelry market and increased use in autocatalysts due to vehicle emissions legislation. Total world demand for 1998 amounted to 5.755 Moz. A predicted steady growth in the consumption of platinum for jewelry and existing applications, together with development of new uses, is expected to result in an annual 250 000 oz increase in demand for 1999 and 2000. The derived supply and demand balance for 1998 shows a small excess in supply relative to demand. This will be absorbed by inventories and is likely to have little affect on price, A significant shortfall of 410 000 oz, however, is predicted for 1999. This is likely to be followed by a further shortfall in 2000 and will drive up prices, impel consumers towards substitution and thriving and encourage producers to expand.
198

Essays in Consumer Behavior

Farina, Tatiana Mercier Querido January 2012 (has links)
Thesis advisor: Frank Gollop / My doctoral dissertation consists of three essays on consumer behavior. The first chapter studies demand for experience goods. Consumers behave very differently when they do not have perfect information about all brands available on a shelf. This paper extends the benchmark discrete choice model of consumer demand to capture two distinct features of experience-goods markets: prior brand experience and shopping frequency. Although the current literature incorporates habit formation in consumer demand models, it has not considered a more fundamental question: how the first experience with a brand affects the consumer's choice. The model is estimated using data on purchases of ready-to-drink orange juice, which comes from a new consumer-level panel provided by a large supermarket chain in Brazil. The results show that for this product prior experience of a brand is more important for a consumer's choice than price. Furthermore, own- and cross-price elasticities change significantly when experience and shopping frequency are taken into account. The findings of this chapter have implications for both firms' strategies and for antitrust analysis related to experience-goods markets. The second chapter explores how umbrella branding can significantly decrease consumer's first-time experience cost. Multiproduct firms often market their products under the same brand name. When a firm launches a new product with the same brand name, consumers can pool their prior experience with the brand to infer a quality for the product. This strategy can be particularly useful when a firm decides to enter a market of experience goods, in which consumers face a cost for trying a new product. The main objective of this chapter is to study the process by which consumers' brand choices and first-time purchases for ready-to-drink orange juices are affected by their experience with the same brand in another category. The results are consistent with signaling theories of umbrella branding as they indicate that consumers' experience cost with a product decreases with experience of other products of the same brand. The third chapter is about a household's choice of retail formats. Thirty percent of households' food expenditure in the United States comes from clubstores, mass merchandisers, supercenters, drugstores and convenience stores. However, earlier work focused on consumers' shopping behavior mostly in grocery stores and has not examined consumers choice across different types of retail outlets. To address this gap a multinomial logit model is estimated on household-level scanner data for the United States to study how households' characteristics are related to their choice of retail outlets. The results show that income, household size and ethnicity significantly affect these choices. These findings are important for policies that target certain consumer groups. / Thesis (PhD) — Boston College, 2012. / Submitted to: Boston College. Graduate School of Arts and Sciences. / Discipline: Economics.
199

Theoretical and Empirical Essays on Strategic Behavior in Various Industries

Yurtseven, Caglar January 2011 (has links)
Thesis advisor: Utku Unver / This dissertation consists of three theoretical and empirical essays. In all essays strategic behavior is a key factor. The first essay tries to explain certain pricing behaviors in cellular communication markets using social interactions as a basis for modeling. The second essay estimates the demand in the Turkish dishwasher market. It utilizes the complaint call rate for a firm as a new explanatory variable in the estimation process. The last essay examines the effects of market share restrictions on the cost reduction efforts of firms in a market. The first essay develops a model of competition in cellular network markets. People's choices are investigated in their social environments with differing utilities for different calls, which creates the distinctive part of this article. People get higher utilities from talking to people who are closer to them in the social environment. In the constructed market, different tariff types, per unit pricing and two part tariffs are examined for the existence of non-monopoly equilibria. In the well-known papers of the literature, different prices for in-line and between-line calls are justified with different cost structures for in-line and between-line calls. This essay is different from the literature because it is able to explain price discrimination with customer necessities and without cost differences. For per unit charging, assuming each firm has different costs which are larger than zero, the smaller cost firm gets a higher share with lower prices in the equilibrium. For two part tariffs with costs higher than zero and different from each other, a two firm equilibrium is reached in which the higher cost firm charges higher prices and a lower fixed fee, whereas the lower cost firm charges lower prices and a higher fixed fee. The second chapter is the empirical essay of this dissertation. In demand estimations, unobserved characteristics like perceived quality or after-sale service quality of products have created omitted variable bias. In the essay, the complaint call rate for a product is offered as a proxy to solve the endogeneity problem that arises from unobserved heterogeneity. Using demand and supply estimations of the Turkish dishwasher market, the complaint call rate is shown to be a valid proxy to solve the problem. Use of this proxy is possible under less restrictive assumptions than the popular instrumental variable method, which is also offered for the solution of the same problem. In addition, the model constructed in the essay has strong testable implications and is demonstrated to be consistent with a stable market of a leader firm and followers. Demand and supply elasticities of dishwashers are estimated for Turkey, which can help durable goods firms to use their investment and marketing resources more efficiently in emerging countries. The third essay studies the effects of market share restrictions on research and development effects of firms in a market. Market share of firms are closely followed by regulatory authorities and restrictions are applied in many cases around the world. This essay investigates if these restrictions affect the cost reduction efforts of the firms in a market. The theoretical model constructed shows that under the no exit assumption, market share restrictions lower the level of competition and possible rewards from R&D efforts, therefore causing smaller levels of R&D efforts both for big and small firms in the market. / Thesis (PhD) — Boston College, 2011. / Submitted to: Boston College. Graduate School of Arts and Sciences. / Discipline: Economics.
200

Estudo do comportamento da demanda do aço laminado plano nos mercados interno e externo. / Flat steel demand behavior in the domestic and international market.

Alves, Marco Aurélio Bruno 05 October 2006 (has links)
A presente investigação teve como objetivo estudar o comportamento do preço do aço laminado plano não revestido nos mercados internacional e nacional, com ênfase à bobina de aço laminada a quente, produto com maior volume negociado internacionalmente dentre os aços planos. Tendo como premissa que esse produto é uma commodity, e que o seu preço internacional é ditado por um mercado competitivo a partir da relação entre oferta e demanda, o trabalho identifica o grau de influência de algumas variáveis independentes sobre a função demanda do produto, tais como renda, geografia, novos atores internacionais e crises políticas, dentre outras. Os resultados obtidos demonstraram que, no mercado nacional, os preços internacionais e o imposto de importação têm grande influência sobre a formação do preço das usinas produtoras. Para possibilitar ao leitor um melhor entendimento sobre o setor siderúrgico, esta dissertação também descreve o setor, contemplando a sua história e evolução, as tecnologias usadas, os produtos gerados, a alocação geográfica dos mercados produtor e consumidor, a organização empresarial desse tipo de negócio, os eixos de comércio e a análise das forças competitivas. / The work study the price behavior of the flat rolled steel not coated, with focus on the hot rolled steel coil, on the international and national market. Starting with the supposition that the studied product is a commodity and that its international price are made in a competitive market, from the offer and demand relationship, the work try to identify de influence degree of some independent variables over the product demand function: Income, geography, international new players, economic e politic crisis, etc. In the national market, the work show the influence of the international prices and the import duty over the steel making price curve. To permit a better understanding about the steel industry, the work describe this industry, showing his history, evolution, used technology, the products, his geography, business organization, trade axis and analise the competitive forces.

Page generated in 0.0955 seconds