• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 1162
  • 351
  • 205
  • 138
  • 118
  • 84
  • 68
  • 22
  • 20
  • 19
  • 16
  • 14
  • 14
  • 13
  • 12
  • Tagged with
  • 2691
  • 597
  • 469
  • 360
  • 301
  • 211
  • 195
  • 191
  • 189
  • 184
  • 176
  • 165
  • 160
  • 158
  • 135
  • 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.
981

Pequeno mapeamento de espaços experenciados : inventário de impressões e compartilhamentos

Wendt, Kelly January 2017 (has links)
Esta pesquisa é construída através de uma investigação poética sobre o processo de criação do Mapeamento Geoperceptivo de espaços experenciados, que reúne em inventários coleções de imagens de espaços abandonados urbanos encontrados por meio de percursos realizados na cidade de Pelotas-RS. Revisita conceitos e noções de outras áreas, como a geografia, a história e a filosofia para definir os espaços experenciados como o encontro do corpo no espaço e tempo, assim como refere-se a errância no contexto da arte para pensar os modos operatórios do trabalho. Procura uma compreensão das linguagens, da fotografia, da impressão e do compartilhamento usadas em consonância com a poética e importante para a área. Os espaços experenciados estão reunidos em grupos de trabalhos organizados em dois inventários conforme o modo a linguagem utilizada. O Inventário UM reúne trabalhos sobre o uso da fotografia enquanto registro de um instante, referindo-se ao documento e ao colecionismo. São apresentados com diferentes dispositivos, como registro digital e por meio de reprodução. O Inventário DOIS concentra os trabalhos que discutem a digitalização, o múltiplo e o compartilhamento. A digitalização dos desenhos é recorrente criando, a possibilidade de reproduzi-las e compartilha-las. As imagens possuem caracter de múltiplos e tem objetivo da circulação. Por fim os trabalhos expressam sobre a memória e o espaço, memorar através da reprodução de imagens, fazendo uma crítica sobre o mau uso do espaço coletivo. A tese refere-se aos trabalhos da poética que tem como resposta ativar a memória espacial trazendo uma leitura perspectiva que questiona o uso da cidade e como a percebemos. / This research is built through poetic research on the process of creating Geoperceptive Mapping of Experienced Spaces. The research, which gathers in inventory collections of abandoned urban spaces, found through routes designed in the city of Pelotas-RS. It revisits concepts and notions of other areas such as geography, history and philosophy to define the experienced spaces as the encounter of the body in space-time, just as it refers to the wandering in the context of art to think about the operative modes of work. It seeks an understanding of the languages, photography, printing and sharing used in harmony with the poetic and important for the area. Experienced spaces are gathered in groups of works organized in two inventories according to the language used. Inventory ONE brings together works on the use of photography as a record of an instant, referring to the document and to collecting. Different dispositives are presented, like digital photography, and through reproduction. The Inventory TWO, concentrates the works that discuss digitalization, the multiple and sharing. The digitalization of the drawings is recurrent, creating the possibility to reproduce and share it. Images are multi-character and have purpose of circulation. Finally the works express about memory and space, to memorize through the reproduction of images, making a critique about the misuse of collective space. The thesis refers to the works of poetics that have the answer activate spatial memory bringing a perspective that questions the use of the city and how we perceive it.
982

A aplicação da pena de sonegados nas partilhas decorrentes do divórcio

Cardoso, Marina Pacheco 17 September 2015 (has links)
Made available in DSpace on 2016-04-26T20:23:53Z (GMT). No. of bitstreams: 1 Marina Pacheco Cardoso.pdf: 1354445 bytes, checksum: 422c8b98744f77eb99e2bd5eb26875eb (MD5) Previous issue date: 2015-09-17 / This investigation discusses some kinds of asset fraud when the dissolution of marriage, the existing legal instruments to reverse loss incurred and, finally, the feasibility of application of penalty for property concealing in divvying up of assets in divorce. The latter considered as a punitive and mainly preventive measure in order to fight malicious disposal of marital estates. First, however, this study presents a brief analysis of the evolution of the family, the concept of heritage and the principles bound to property rights of family relationships. This will enable a better understanding of some rules of conduct that are, in most cases, overlooked by participants of these relations and will also stress the need for better protection of the dignity of the spouses at the time of the breakup of romantic relationships. Finally, this investigation points out the kinds of property regimes and the rules allotted to each one by the legal system, the procedures related to inventory and asset sharing applicable to any kind of asset division, the regulation of the penalty for property concealing which cannot be left out from the category that most cries out for protection and the defect of legal acts in property division / O presente trabalho aborda algumas espécies de fraudes patrimoniais cometidas quando da dissolução do matrimônio, os instrumentos legais existentes para reverter ou minimizar os prejuízos sofridos e, por fim, a viabilidade de aplicação da pena de sonegados nas partilhas decorrentes do divórcio, como medida punitiva, e principalmente, preventiva de combate ao malicioso esvaziamento patrimonial. Antes disso, contudo, expõe uma breve análise da evolução da família, o conceito de patrimônio e os princípios vinculados ao direito patrimonial das relações familiares, para melhor compreensão acerca das regras de conduta esquecidas, na maioria das vezes, pelos partícipes destas relações, bem como para ressalvar a necessidade de maior proteção da dignidade dos cônjuges no momento do rompimento dos relacionamentos amorosos. Aponta as espécies de regimes de bens e o regulamento dado a cada um pelo ordenamento jurídico, bem como o procedimento de inventário e partilha, aplicáveis para qualquer espécie de divisão patrimonial, o regramento do instituto dos sonegados, o qual não há razão de ser afastado da categoria que mais clama por proteção, e os defeitos do negócio jurídico recorrentes nas partilhas de bens
983

Warehousing in theory and practice : A case study at ÖoB, Clas Ohlson, Stadium, Åhlens

Kare, Sridhar, Kumar Rajuldevi, Mahesh, Veeramachaneni, Ranjit January 2009 (has links)
The problem in the warehouses is that the old and conventional methods which are obsolete are combined with very crowded conditions. Hence there is always a quest for newer and better methods. However, merely installing the newer methods does not mean that the system is effective and efficient, there is also necessity of a strong supervisory organization of the system to make the methods more effective and this also requires lot of training and managing the operations.The purpose of this thesis is to give an overview and to briefly present the concept of warehousing. Analysing the present situation in warehouses by examining four of the biggest retail warehouses in Sweden with the help of a questionnaire given to the respective warehouse managers. Comparing the present situation to the theoretical framework in order to get an idea of the strategies deployed by the businesses.The warehouses today are deploying a mixture of both latest strategies and technologies and the traditional methods in order to have a good efficiency in the warehouses.
984

Análise do uso da tecnologia laser aerotransportado para inventários florestais em plantios clonais de Eucalyptus sp no sul da Bahia / Analysis of the airborne laser scanning technology use for forest inventories in cloned Eucalyptus sp plantations in the southern Bahia.

Zonete, Matheus Felipe 19 June 2009 (has links)
A aplicação da tecnologia LASER aerotransportado (ALS) para realização de inventários florestais, tem se apresentado como excelente alternativa para a área de planejamento florestal, principalmente pelos ótimos resultados em termos de precisão das estimativas, pelas facilidades de uso e demais produtos e benefícios advindos do sobrevôo com o LASER. A evolução e o menor custo das tecnologias GPS e Sistemas de Medição Inercial têm sido o principal fator de sucesso para a aplicação da tecnologia ALS. Vários trabalhos de análise da tecnologia LASER aerotransportado, em inventários florestais, alguns até mesmo em escalas comerciais (NAESSET, 2007), têm sido realizados principalmente na Europa e no Canadá. Os resultados têm sido muito atraentes, dentre os quais se destacam as estimativas de volume e de área basal que têm apresentado erros de no máximo 8,4%, dependendo das configurações da área amostrada. Sendo assim, este trabalho teve por objetivo analisar o uso da tecnologia ALS para a realização de inventários florestais em níveis de parcela e talhão em plantios clonais de Eucalyptus sp, no sul do estado da Bahia. Para tanto foram realizados levantamentos de campos que permitiram a estimação de parâmetros como área basal, altura de árvores média e das dominantes e volume, em parcelas circulares de treze metros de raio, nas quais foram coletados o diâmetro de todas as árvores e a altura de uma a cada sete árvores da parcela. A área sobrevoada para coleta dos dados LASER foram duas faixas de aproximadamente 2x20km. Os dados LASER foram processados para se obter os percentís das observações ALS nos níveis 10 (f_h10), 30 (f_h30), 50 (f_h50), 70 (f_h70) e 90 (f_h90), bem como a densidade de pontos nos respectivos percentís (f_p10, f_p30, f_p50, f_p70 e f_p90), e a altura média (f_havg) e o desvio padrão (f_hstd) desses pontos. Essas estatísticas foram utilizadas em modelos de regressão para estimar diâmetro médio, altura média, altura dominante, área basal e volume das parcelas amostradas. Para o volume, uma avaliação exploratória de diferentes combinações de variáveis permitiu a definição das relações mais promissoras e a utilização dessas variáveis mais promissoras no ajuste de modelos já consagrados na área de biometria e inventário florestal. As observações ALS que melhor ajustaram diâmetro médio foram f_h30 e f_p30, com R²=0,88 e RQEM%=0,0004; para altura média, f_h10 e f_h90 geraram boas estimativas, com R²=0,94 e RQEM%=0,0003, enquanto que para altura dominante, as melhores estimativas foram obtidas com f_h90, apresentando R²=0,96 e RQEM%=0,0003; e para área basal, os melhores ajustes usaram idade, f_h10 e f_havg, sendo R²=0,92 e RQEM%=0,0016. No caso de volume, os dois melhores modelos exploratórios apontam para o uso de idade, f_h30 e f_p90, em ambos os casos, e ambos com R² entre 0,94 e 0,95 e RQEM% entre 0,002 e 0,003. Já, dentre os modelos biométricos testados, os melhores foram os de Schumacher ajustado com idade e f_h90; Clutter ajustado com idade, f_havg e f_h70; e de Buckman ajustado com idade, f_havg e f_h10. / The application of the airborne laser scanning (ALS) technology for forest inventories execution, have been presented as an excellent alternative to the forest planning area, particularly by the excellent results in terms of accuracy of the estimates, by the facilities of usage and other products and benefits derived from LASER overflight. The technology evolution and lower cost for GPS and Inertial Measurement Units have been the main factor of the success for ALS technology application. Several studies of ALS technology analysis in forest inventories, some even in commercial scales (NAESSET, 2007), have been conducted mainly in Europe and Canada. The results have been very attractive, among which there are the volume and basal area estimates which have made errors of up to 8.4% depending on the settings of the sampled area. Thus, this study aimed to examine the use of the ALS technology for forest inventories executions at plot and stands levels in clonal Eucalyptus sp plantations in the south of Bahia state. Field surveys were conducted to provide the parameters estimation such as diameter, tree heights, basal area and volume in circular plots of thirteen-meter radius, which were the diameter of all trees and height of a the seven trees of each plot. The overflown areas for LASER data collection were two bands of approximately 2x20km. LASER data were processed to obtain the percentiles of the ALS observations in the following levels 10 (f_h10), 30 (f_h30), 50 (f_h50), 70 (f_h70) e 90 (f_h90), and 90 (f_h90) and the density of points in the respective percentiles (f_p10, f_p30, f_p50, f_p70 and f_p90), the average height of the points (f_havg) and the standard deviation (f_hstd). These statistics were used in the regression models to estimate mean diameter, mean height, dominant height, basal area and volume of the sampled plots. For the volume, an exploration of different combinations of the variables supported the definition of the most promising relations and most promising use of these variables in the set of models already established in the biometrics and forest inventory area.The ALS observations that better fit to the average diameter were f_h30 and f_p30, resulting in a R²=0.88 and RQEM%=0.0004; for the average height, f_h10 and f_h90 generate good estimates, having R²=0.94 and RQEM%=0. 0003, therefore for the dominant height, the best estimates were obtained with f_h90, showing R²=0.96 and RQEM%=0.0003. For the basal area, the best fit used age, f_h10 and f_havg, presenting a R²=0.92 and RQEM%=0.0016. In the volume case, the two best exploratory models point to the use of age, f_h30 and f_p90, both with R ² between 0.94 and 0.95 and RQEM% between 000.2 and 000.3. Among the biometric tested models, the best were Schumacher fitted by age and f_h90; Clutter fitted by age, f_havg and f_h70; Buckman fitted by age, f_havg and f_h10.
985

O fitoplâncton na Zona Costeira Amazônica Brasileira: Biodiversidade, distribuição e estrutura no continuum estuário-oceano / Phytoplankton in the Brazilian Amazon Coastal Zone: Biodiversity, distribution and structure in estuary-ocean continuum

Lourenço, Caio Brito 04 November 2016 (has links)
A biodiversidade e a estrutura da comunidade fitoplanctônica na Zona Costeira Amazônica Brasileira foi avaliada com base em 272 publicações, relativas ao período entre 1861 e 2016, e a partir de oito cruzeiros oceanográficos realizados em diferentes fases do ciclo do Rio Amazonas entre os anos de 2013 a 2015. A seleção das publicações restringiu-se as que apresentaram identificação taxonômica, em diferentes níveis, e/ou quantificação, expressa em densidade celular, obtidas exclusivamente através de microscopia ótica. A composição específica e a densidade celular do fitoplâncton foram avaliadas através da metodologia Utermöhl (1958). As informações disponíveis, principalmente sob a forma de resumos em congressos (67%), monografias (13%) e artigos publicados em periódicos (11%), foram resgatadas de estudos desenvolvidos no litoral dos Estados do Pará (131), Maranhão (105) e Amapá (3), assim como na plataforma continental (36). Entre os ecossistemas mais bem estudados, estão os estuários (135 referências), plataforma continental (36 referências) e as praias (30), sendo o enfoque ecológico o principal objetivo das investigações científicas (96%). Atualmente, o inventário de espécies inclui 1157 táxons distribuídos em 612 diatomáceas, 252 dinoflagelados, 199 clorofíceas, 56 cianobactérias, 19 cocolitoforídeos, 19 euglenofíceas e uma criptofícea. Com base nesta revisão e nas amostragens realizadas neste estudo, a análise da estrutura da comunidade fitoplanctônica na Plataforma Continental Amazônica é característica de ambientes costeiros sob influência de plumas fluviais, com dois cenários ecológicos relacionados aos períodos de vazão do Rio Amazonas: um de maior influência, nos meses de abril e julho, e outro oposto, nos meses de outubro e janeiro. Observou-se uma distribuição em faixas, de acordo com as características ambientais e a estrutura da comunidade fitoplanctônica, divididas em plataforma interna sob influência da pluma, zona de transição e plataforma externa com influência oceânica. As Diatomáceas são responsáveis pelas altas densidades (105 cel.L-1) na região costeira, especialmente sob influência da pluma, contribuindo para o incremento de Clorofila a (>10 &mu;g.L-1). Na porção oceânica, sem influência da pluma, as concentrações de Cla são baixas (<2 &mu;g.L-1) e predominam (104 cel.L-1) as cianobactérias filamentosas e cocolitoforídeos. A variabilidade temporal da descarga do Rio Amazonas e, consequentemente, da dinâmica espacial da pluma, é o principal fator responsável por mudanças na salinidade e disponibilidade de nutrientes, determinando a estrutura da comunidade fitoplanctônica. Este estudo reforça a importância da manutenção de séries temporais e o levantamento da biodiversidade para a compreensão da dinâmica da comunidade fitoplanctônica em ambientes de alta complexidade, como a Plataforma Continental Amazônica. / Phytoplankton biodiversity and structure in the Brazilian Amazon Coastal Zone was evaluated based on 272 publications from the period between 1861 and 2016 and from eight oceanographic cruises carried out in different phases of the Amazon river hydrograph between the years 2013 to 2015. Selected publications were restricted to those which presented taxonomic identification at different levels, and / or quantification in terms of cell density, obtained exclusively by optical microscopy. Specific composition and phytoplankton cell density was evaluated by Utermöhl methodology (1958). Available information in the form of conference abstracts (67%), monographs (13%) and journal articles (11%) were rescued from studies developed on the coast of Pará (131), Maranhão (105) and Amapá (3), as well as on the continental shelf (36). Within these, the best studied ecosystems are estuaries (135 references), the continental shelf (36 references) and the beaches (30), with an ecological approach as the main research objective (96%). Currently, species inventories include 1157 taxa, distributed in 612 diatoms, 252 dinoflagellates, 199 chlorophytes, 56 cyanobacteria, 19 coccolithophorids, 19 euglenoids and one criptoficean. Based on this review and on the results obtained in this study, the structure of the phytoplankton community in the Amazon Continental Shelf is characteristic of coastal environments under the influence of river plumes, with two ecological scenarios related to the Amazon river discharge, one with greater influence in April and July and another with less influence in October and January. The distribution occurs in bands, according to the environmental characteristics and the structure of the phytoplankton community, divided into internal continental shelf under the influence of the plume, transition zone, and external continental shelf with oceanic influence. Diatoms are responsible for the high densities (105 cells.L-1) in the coastal region, especially under the influence of the plume, contributing with the increase of chlorophyll a (> 10 &mu;g.L-1). At the oceanic portion without influence of the plume, Cla concentrations are low (<2 &mu;g.L-1) and filamentous cyanobacteria (104 cells.L-1) and coccolithophorids dominate. The temporal variability of the discharge of the Amazon river and, consequently, the spatial dynamics of the plume, is the main factor responsible for changes in salinity and nutrient availability, determining the structure of the phytoplankton community. This study reinforces the importance of maintaining time series and biodiversity surveys to understand phytoplankton community dynamics in highly complex environments such as the Continental Amazon Shelf.
986

A single reverse procurement auction in a multi-period setting with inventory decisions.

January 2005 (has links)
Chan Ying Leung. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2005. / Includes bibliographical references (leaves 85-89). / Abstracts in English and Chinese. / Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Importance of Reverse Auctions --- p.1 / Chapter 1.2 --- A Research Gap in Existing Literatures --- p.3 / Chapter 1.3 --- Research Focus --- p.4 / Chapter 1.4 --- Contributions of This Thesis --- p.5 / Chapter 1.5 --- Organization of This Thesis --- p.5 / Chapter 2 --- Background and Literature Review --- p.6 / Chapter 2.1 --- Review of Reverse Auctions --- p.6 / Chapter 2.1.1 --- Benefits of Reverse Auctions to Buyers --- p.9 / Chapter 2.1.2 --- Types of Reverse Auctions --- p.11 / Chapter 2.1.3 --- Implementation of the Entry-fee Reverse Auction --- p.13 / Chapter 2.2 --- Linkage between the Entry-fee Reverse Auction and the Multi- period Inventory Replenishment Model --- p.16 / Chapter 2.3 --- The Multi-period Inventory Replenishment Model with TOQC --- p.17 / Chapter 3 --- The Basic Models --- p.18 / Chapter 3.1 --- Strategic Sourcing Methodology - The Entry-fee Reverse Auc- tion --- p.18 / Chapter 3.1.1 --- Numerical Example --- p.26 / Chapter 3.2 --- Operational Procurement Methodology ´ؤ The Multi-period Inventory Replenishment Model with TOQC --- p.29 / Chapter 3.2.1 --- Numerical Example --- p.33 / Chapter 3.3 --- Chapter Summary --- p.34 / Chapter 4 --- Modifications Required for Integrating the Entry-fee Reverse Auction and the Multi-period Replenishment Model with TOQC --- p.36 / Chapter 4.1 --- Formulation of the Buyer's Expected Profit Function in the Multi-period Setting --- p.37 / Chapter 4.2 --- The Existence of Optimal TOQC --- p.38 / Chapter 4.2.1 --- Convexity of the Last-period Optimality Equation --- p.39 / Chapter 4.2.2 --- Convexity of the Two-period Problem --- p.41 / Chapter 4.2.3 --- Convexity of the N-period Problem --- p.44 / Chapter 4.3 --- The Computability of the Optimal TOQC --- p.47 / Chapter 4.4 --- Chapter Summary --- p.47 / Chapter 5 --- The Revised Model --- p.48 / Chapter 5.1 --- The Entry-fee Reverse Auction in the Multi-period Setting with TOQC --- p.48 / Chapter 5.1.1 --- Numerical Example --- p.55 / Chapter 5.2 --- Chapter Summary --- p.59 / Chapter 6 --- Numerical Analysis --- p.60 / Chapter 6.1 --- Comparison between the Fixed-quantity Reverse Auction and the Entry-fee Reverse Auction --- p.60 / Chapter 6.1.1 --- Number of Supplier --- p.63 / Chapter 6.1.2 --- Retail Price --- p.65 / Chapter 6.1.3 --- Coefficient of Variation for Demand Distribution . --- p.66 / Chapter 6.1.4 --- Average Improvement --- p.67 / Chapter 6.2 --- Duration of the Entry-fee Reverse Auction Cycle --- p.68 / Chapter 6.3 --- Chapter Summary --- p.76 / Chapter 7 --- Factors of Success for Holding the Entry-fee Reverse Auction --- p.77 / Chapter 7.1 --- Internal Organizational Infrastructure of the Buyer --- p.77 / Chapter 7.2 --- Supplier's Qualifications and Control --- p.78 / Chapter 7.3 --- Attractions of the Entry-fee Reverse Auction for Suppliers . . --- p.78 / Chapter 7.4 --- Procedural Fairness --- p.81 / Chapter 7.5 --- Total Cost Analysis --- p.81 / Chapter 7.6 --- Chapter Summary --- p.82 / Chapter 8 --- Concluding Remarks --- p.83 / Bibliography --- p.85 / Chapter A --- Order Statistics --- p.90 / Chapter B --- Conditional Order Statistics --- p.92 / Chapter C --- Virtual Marginal Cost of Procurement --- p.93
987

Inventory control and dynamic pricing for inventory systems with delivery time options. / CUHK electronic theses & dissertations collection / Digital dissertation consortium

January 2010 (has links)
The efficiency of revenue management relies on the effectiveness of the strategies it employs. In the competing market nowadays, time has become an important concern at both demand and supply sides. With time-sensitive customers and additional benefits from intertemporal demand shift, we find that the sellers could turn to a time-differentiation based strategy as an effective revenue management tool. Motivated by real-life business issues of Toyota China dealerships, in this thesis, we consider stylized inventory-control models with delivery upgrades, in which the seller allocates its on-hand inventory to price and delivery-time sensitive customers. The seller provides two delivery-time options with different prices. Customers choose the proper purchasing option according to their heterogeneous preferences. The seller has two decisions: inventory commitment and inventory replenishment. The former addresses, within an inventory cycle, how on-hand inventories are allocated between the two classes of customers. The latter addresses, between inventory cycles, how the inventory is replenished. Furthermore, the seller may employ early delivery, namely upgrade, to achieve a higher inventory flexibility. We develop the optimal inventory allocation and upgrade, and inventory replenishment policies, and demonstrate that the optimal control can be characterized by a switching curve. Based on the basic model setting, we extend our analysis to include cases of upgrade cost, stock-out substitution, and capacity constraint. We further discuss the joint pricing and inventory decision. We obtain the form of the optimal joint policy, and show that the two strategies may well complement each other in our setting. When each is applied separately, their performances are also compared. To shed more light on the practical side, finally, we use the Toyota dealership data to calibrate the required parameters, and demonstrate the potential of the optimal inventory allocation and upgrade control. / Liang, Xiaoying. / Advisers: Houmin Yan; Youhua Chen. / Source: Dissertation Abstracts International, Volume: 72-04, Section: B, page: . / Thesis (Ph.D.)--Chinese University of Hong Kong, 2010. / Includes bibliographical references (leaves 118-124). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. Ann Arbor, MI : ProQuest Information and Learning Company, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. Ann Arbor, MI : ProQuest Information and Learning Company, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese.
988

Inventory and procurement management in the presence of spot markets. / CUHK electronic theses & dissertations collection

January 2009 (has links)
In the first model, we study the optimal procurement strategy in a two-period framework when both the spot market and the forward contract are considered. The forward contract is agreed upon in the first period, and is then delivered in the second period, when the spot market is also available. This is followed by production and demand. The objective of the buyer is to minimize his expected cost. We study the problem for two scenarios: the buyer cannot and can sell to the spot market. Through our analysis, when the buyer can not sell to the spot market, there exists a threshold forward price, under which the buyer will enter into the forward contract. This threshold is lower than the expected spot price. Furthermore, we analytically show that the optimal order quantities via forward contract increase in the mean of the spot price, but decrease in the variability of the spot price. However, the buyer only speculates using the forward contract when he can sell to spot market. / In the second model, we consider a problem in which a buyer makes procurement decisions when he faces periodic random demand and two supply sources, one is a long-term contract supplier and the other is a spot market. When he procures from the contract supplier, a fixed unit price is charged and a predetermined minimum quantity for each period must be committed, and when he procures from the spot market, a stochastic spot price plus a fixed setup cost is charged. The spot price is only realized at the beginning of each period. We show that the optimal policy consists three different (s, S) type policies. More important, we identify certain conditions under which there exist monotone properties between the policy parameters and the current spot price for a general Markov spot price process. Then, we can divide the price space into three regions, each of which corresponds to a specific policy, for each period. We also conduct numerical analysis to gain more insights into how the spot market impacts the buyer's performance. We find the buyers benefits from a more volatile market. / The last model extends the second model by incorporating an important feature that is widely seen; i.e., the procurement from the contract supplier should fulfill a total order quantity commitment (TOQC). The TOQC requires the buyer to procure no less than the predetermined commitment during the contract period, which we call the planning horizon. Thus, in each period, the buyer trades off between the possible lower cost now (by procuring from the spot market) and the reduced cost in the future (by reducing the remaining commitment). Two types of commitment contracts are considered: a minimal TOQC contract and a definite quantity contract. Our analysis characterizes an optimal procurement policy which depends on the spot price in each period and an optimal virtual remaining commitment level. Such a structured policy can be viewed as a combination of some policies of base-stock type, each of which can be computed through an equivalent system without any commitment. Moreover, some of these equivalent systems are of simple multiple-period newsvendor type. This greatly simplifies the computation of the optimal policies. We also numerically analyze how the TOQC and the spot market affects the buyer's performance. / This research develops mathematical models for inventory and procurement management in the presence of spot markets. More specifically, we consider those models by incorporating different types of supply contracts. Particular attention is paid to the quantity flexible contracts. This research is an attempt to understand how firms should adopt their operating policies in the presence of fluctuating commodity prices. In this thesis, we mainly consider the following three models. / Xue, Weili. / Adviser: Youhua Chen. / Source: Dissertation Abstracts International, Volume: 72-11, Section: B, page: . / Thesis (Ph.D.)--Chinese University of Hong Kong, 2009. / Includes bibliographical references (leaves 122-134). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [201-] System requirements: Adobe Acrobat Reader. Available via World Wide Web.
989

Inventory models with weather derivatives and weather-conditional rebates for seasonal products. / CUHK electronic theses & dissertations collection / ProQuest dissertations and theses

January 2007 (has links)
Key words. Newsvendor Model, Inventory Model, Seasonal Product, Weather Risk, Weather Option, Weather Derivative, Weather-Conditional Rebate, CVaR, Mean-CVaR. / The first model considers the problem of hedging inventory risk for a newsvendor who sells a seasonal product. The newsvendor not only decides the order quantity, but also adopts a weather hedging strategy. A typical hedging strategy is to use an option that is constructed on a weather index before the season begins, which will compensate the buyer of the option if the actual seasonal weather index is above (or below) a given strike level. We explore the joint decision problem in mean-variance, expected utility, conditional value-at-risk (CVaR), and mean-CVaR frameworks. We analyze the impact of weather hedging on optimal order quantity. It is proven that the newsvendor may order more than in the absence of weather options. Numerical analysis on the sensitivity of the optimal order quantity, the risk premium of the option, the portfolio selection and the comparison between the weather option hedging and a particular operational hedging are presented as well. / The second model investigates the advantages of early sales of a seasonal product. To induce early sales, the newsvendor adopts a weather-conditional rebate program, which will pay rebates to the customers who buy the product in the preselling period if a specified weather condition for normal selling season is realized. For an example, a certain amount of refund will be paid to early buyer if the seasonal average temperature falls below the past-three-year seasonal average. Two conditional rebate programs with early booking and early purchasing are investigated and compared. Both of them can price differentiate within a customer among his/her post valuation on the seasonal product, and thus increase the sales. For the early purchasing program, it can further save inventory holding cost and ordering cost. The expected profit can be improved by the programs. Moreover, combined with weather derivatives, the conditional rebate program can manage the financial risk with the expected profit being still improved. / To investigate the means that firms may adopt in managing the adverse impacts of weather on their businesses, this dissertation proposes and analyzes two inventory models for seasonal products when the demand is sensitive to the weather in the season. Both models are formulated under the newsvendor context. / Gao, Fei. / "October 2007." / Adviser: Youhua Frank Chen. / Source: Dissertation Abstracts International, Volume: 69-08, Section: B, page: 5002. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2007. / Includes bibliographical references (p. 108-119). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. Ann Arbor, MI : ProQuest dissertations and theses, [201-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstracts in English and Chinese. / School code: 1307.
990

Inventory models with downside risk measures. / CUHK electronic theses & dissertations collection

January 2007 (has links)
Finally, we study a multi-period, risk-averse inventory model. The objective is to maximize the expected pay-offs. The risk-averse behavior is modeled as to penalize the decision maker if a target-profit level is not satisfied for each financial reporting cycle. We recognize that the operational period is usually faster than the financial reporting cycle. Therefore, the financial reporting cycle can be considered as an integer times of the operational periods. We study this model under both accrual-basis accounting principle and cash-basis accounting principle. We prove that the optimal inventory policy is a state-dependent base-stock policy under the accrual-basis accounting method. We then show that the structure of an optimal policy is a complicated one for the cash-basis accounting method. / In this thesis we study three supply chain models which address downside risk from a different angle. We start with a commitment-option supply contract in a Conditional Value-at-Risk (CVaR) framework. We show that a CVaR trade-off analysis with advanced reservation can be carried out efficiently. Moreover, our study indicates how the corresponding contract decisions differ from decisions for optimizing an expected value. / Key words. Downside Risk Measure; CVaR; Risk; Loss-Averse; Dynamic Programming. / Owing to the growing globalization in economy and the advances in commerce, research in supply chain management has attracted large number of researchers in the last two decades. Yet standard treatments of supply chain models are mainly confined for the optimization of expected values with little reflection on risk considerations. Even for those that consider a risk measure in the objective function, there are quite few literatures employing downside risk measure. The downside risk measure takes into account only the part of the distribution that is below a critical value. Thus it indicates a safety-first strategy for decision maker. / The thesis is organized in five chapters. In Chapter 1, we provide the background and research motivation for considering downside risk measures in supply chain models. In Chapter 2, we study the pay-to-delay supply contracts with a Conditional Value-at-Risk (CVaR) framework. In Chapter 3, we study the loss-averse newsvendor problem. In Chapter 4, we extend the loss-averse model to a multi-period setting. We conclude the thesis in Chapter 5 with discussions for future research. / Then, we employ a loss-aversion utility function to characterize newsvendor's decision-making behavior. We find that when there is no shortage cost, the loss-averse newsvendor consistently orders less than a risk-neutral newsvendor. Further, we discover that the loss-averse newsvendor orders a constant quantity when the reference target is sufficiently large. We discuss the importance of initial inventory to achieve the target profit level. When the target is a decision variable, the newsvendor always sets the target no higher or no lower. / Ma, Lijun. / "October 2007." / Adviser: Houmin Yan. / Source: Dissertation Abstracts International, Volume: 69-08, Section: B, page: 5003. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2007. / Includes bibliographical references (p. 140-154). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstracts in English and Chinese. / School code: 1307.

Page generated in 0.0876 seconds