Constructive solution methodologies to the capacitated newsvendor problem and surrogate extension

The newsvendor problem is a single-period stochastic model used to determine the order quantity of perishable product that maximizes/minimizes the profit/cost of the vendor under uncertain demand. The goal is to fmd an initial order quantity that can offset the impact of backlog or shortage caused by mismatch between the procurement amount and uncertain demand. If there are multiple products and substitution between them is feasible, overstocking and understocking can be further reduced and hence, the vendor\u27s overall profit is improved compared to the standard problem. When there are one or more resource constraints, such as budget, volume or weight, it becomes a constrained newsvendor problem. In the past few decades, many researchers have proposed solution methods to solve the newsvendor problem. The literature is first reviewed where the performance of each of existing model is examined and its contribution is reported. To add to these works, it is complemented through developing constructive solution methods and extending the existing published works by introducing the product substitution models which so far has not received sufficient attention despite its importance to supply chain management decisions. To illustrate this dissertation provides an easy-to-use approach that utilizes the known network flow problem or knapsack problem. Then, a polynomial in fashion algorithm is developed to solve it. Extensive numerical experiments are conducted to compare the performance of the proposed method and some existing ones. Results show that the proposed approach though approximates, yet, it simplifies the solution steps without sacrificing accuracy. Further, this dissertation addresses the important arena of product substitute models. These models deal with two perishable products, a primary product and a surrogate one. The primary product yields higher profit than the surrogate. If the demand of the primary exceeds the available quantity and there is excess amount of the surrogate, this excess quantity can be utilized to fulfill the shortage. The objective is to find the optimal lot sizes of both products, that minimize the total cost (alternatively, maximize the profit). Simulation is utilized to validate the developed model. Since the analytical solutions are difficult to obtain, Mathematical software is employed to find the optimal results. Numerical experiments are also conducted to analyze the behavior of the optimal results versus the governing parameters. The results show the contribution of surrogate approach to the overall performance of the policy. From a practical perspective, this dissertation introduces the applications of the proposed models and methods in different industries such as inventory management, grocery retailing, fashion sector and hotel reservation

Behavioral perspectives on risk sharing in supply chains

Over the past decade, we have witnessed the emergence of a vast body of literature contributing to our understanding of how supply chains should be designed and executed from a normative perspective. Along the way, the gap between ever-more sophisticated theory and industrial reality increased. A growing stream of recent research relaxes the overly simplistic assumptions on human behavior commonly made in supply chain models. This thesis contains a set of research papers on human behavior, casted in a unified framework of supply chain inventory risk management

The impact of prices on boundedly rational decision makers in supply chains

This PhD thesis was motivated by the simple observation that the objectives of distinct supply chain managers are often conflicting. This problem is usually addressed via supply chain contracts that are designed to align the incentives of the different supply chain partners to the overall benefit of the entire supply chain, when seen as a whole. In this way, the long-term prosperity and viability of all the firms that participate in the supply chain can be ensured. In order to study the efficiency of different supply chain contracts in attaining the theoretical optimum performance, there exist a number of standard normative models that predict the decisions of perfectly rational decision makers. But supply chain partners might in reality not make the perfectly rational decisions that these theoretical models predict. This may be because they may lack the required information, or experience cognitive limitations and individual preferences or have only a finite amount of time available. For this reason, they might have to settle at satisficing choices. The result of these ‘boundedly rational’ decisions is a real world of different than expected interactions. Since in this world the standard normative models retain limited predictive power, this PhD thesis aims to explore the true efficiency of the simplest supply chain contract that can exist, namely, the wholesale price contract. In addition, this PhD thesis provides some useful recommendations that aim to help supply chain managers make price and order quantity decisions that would be better aligned with the interests of the overall supply chain. To this end, this study applies an original approach that supplements experiments with human subjects with Agent Based Simulation experiments. In greater detail, informal pilot sessions with volunteers were first conducted, during which knowledge of the underlying decision making processes was elicited. Appropriate Agent Based Simulation models were subsequently built based on this understanding. Later on human subjects were asked to interact with specially designed versions of these Agent Based Simulation models in the laboratory, so that their consecutive decisions over time could be recorded. Statistical models were then fitted to these data sets of decisions. The last stage of this approach was to simulate in the corresponding Agent Based Simulation models all possible combinations of decision models, so that statically accurate conclusions could be inferred. This approach has been replicated for both the simple newsvendor setting and the beer distribution game. The results that are obtained indicate that the overall efficiency of the wholesale price contract differs significantly from the theoretical prediction of the corresponding standard normative models. It varies greatly and depends largely on the interplay between the pricing and ordering strategies that the interacting supply chain partners adopt. In view of this, real world echelon managers are advised to use prices as an effective mechanism to control demand and, also, keep their total supply chain profits in mind when making their respective decisions.EThOS - Electronic Theses Online ServiceUniversity of WarwickWarwick Business SchoolEngineering and Physical Sciences Research Council (EPSRC)Operations Research Society (England)GBUnited Kingdo

Information Reliability in supply chains: The case of multiple retailers

En esta tesis doctoral abordamos el estudio relativo al intercambio de información sobre la demanda dentro de una cadena de suministro cuando las partes interactúan de una forma estratégica. Los distribuidores minoristas forman una agrupación y delegan la gestión del inventario (los pedidos y la asignación) a un planificador central benévolo (CP, por sus siglas en inglés). Cada uno de los minoristas debe enfrentarse a una demanda incierta y dispone de información privada sobre ella como consecuencia de su proximidad al mercado; nos centramos en determinar si entre los minoristas y el CP se produce un intercambio fiable de información sobre la demanda. En primer lugar estudiamos el impacto de diversos mecanismos de asignación sobre el comportamiento en materia de pedidos de los minoristas, cuando la cantidad de inventario total en el almacén central es fija. Los minoristas efectúan los pedidos después conocer de manera privada su demanda. Demostramos analíticamente que los minoristas comunicarán sus necesidades reales, es decir, sus demandas realizadas, de acuerdo a una norma de asignación uniforme pero no de acuerdo a otras normas comunes como, por ejemplo, la noma proporcional o lineal; posteriormente, estudiamos una configuración donde la cantidad de inventario agrupado no es fija, sino más bien una variable de decisión, determinada por el CP después de haber solicitado información de demanda prevista de los minoristas. Las asignación del inventario total, en este caso también, se efectúa después de conocerse las realizaciones de demanda final, pero las demandas finales son de conocimiento común. Entonces, los minoristas pueden influir su asignación solo a través de la cantidad de inventario total. Mediante modelos teóricos asociados a tácticas podemos ver que el reconocimiento de la verdad y la confianza no se encuentran en una situación de equilibrio. A continuación, en un entorno de laboratorio controlado que simula la configuración de la cadena de suministro objeto de consideración, estudiamos el impacto de a) la competencia por el inventario común y b) la incertidumbre del mercado sobre la distorsión de la información, la confianza y la eficacia de la cadena de suministro. Nuestros resultados sugieren que existe una confianza continua cuando los incentivos pecuniarios están alineados y cuando no lo están, lo que viene a desmentir los casos teóricos extremos de minoristas completamente dignos de confianza o que no son fiables en absoluto; incluso aunque la información no sea totalmente fiable, el valor de la comunicación es importante. En última instancia, estudiamos el impacto de la propiedad del inventario sobre las motivaciones de las partes implicadas de cara a compartir de manera honrada sus previsiones de demanda; los inventarios específicos tampoco inducen a decir la verdad. Comparamos los inventarios resultantes y los beneficios de acuerdo con la toma de decisiones a nivel local con información más precisa con respecto a la toma de decisiones centralizada, mediante la cual se logra la coordinación de los pedidos

An Empirical Investigation Of Information Technology Mediated Customer Services In China

Information technology mediated customer service is a reality of the 21st century. More and more companies have moved their customer services from in store and in person to online through computer or mobile devices. Using 208 respondents collected from two Chinese universities, this paper investigates customer preference over two service delivery model (either in store or online) on five type of purchasing (retail, eating-out, banking, travel and entertainment) and their perception difference in customer service quality between those two delivery model. Results show that a majority of Chinese students prefer in store and in person for eating out. For ordering tickets for travel and entertainment, they prefer computer/mobile device. For retail purchasing and banking, less than half of the students prefer in person services. In general, the results show that ordering through computer/mobile devices has become more popular in China and has received higher rating for most of customer service quality except security compared to ordering in store. In addition, it is found that there exist a gender difference in purchasing preference and perception in service delivery quality in China

Fuelling the zero-emissions road freight of the future: routing of mobile fuellers

The future of zero-emissions road freight is closely tied to the sufficient availability of new and clean fuel options such as electricity and Hydrogen. In goods distribution using Electric Commercial Vehicles (ECVs) and Hydrogen Fuel Cell Vehicles (HFCVs) a major challenge in the transition period would pertain to their limited autonomy and scarce and unevenly distributed refuelling stations. One viable solution to facilitate and speed up the adoption of ECVs/HFCVs by logistics, however, is to get the fuel to the point where it is needed (instead of diverting the route of delivery vehicles to refuelling stations) using "Mobile Fuellers (MFs)". These are mobile battery swapping/recharging vans or mobile Hydrogen fuellers that can travel to a running ECV/HFCV to provide the fuel they require to complete their delivery routes at a rendezvous time and space. In this presentation, new vehicle routing models will be presented for a third party company that provides MF services. In the proposed problem variant, the MF provider company receives routing plans of multiple customer companies and has to design routes for a fleet of capacitated MFs that have to synchronise their routes with the running vehicles to deliver the required amount of fuel on-the-fly. This presentation will discuss and compare several mathematical models based on different business models and collaborative logistics scenarios

Maritime expressions:a corpus based exploration of maritime metaphors

This study uses a purpose-built corpus to explore the linguistic legacy of Britain’s maritime history found in the form of hundreds of specialised ‘Maritime Expressions’ (MEs), such as TAKEN ABACK, ANCHOR and ALOOF, that permeate modern English. Selecting just those expressions commencing with ’A’, it analyses 61 MEs in detail and describes the processes by which these technical expressions, from a highly specialised occupational discourse community, have made their way into modern English. The Maritime Text Corpus (MTC) comprises 8.8 million words, encompassing a range of text types and registers, selected to provide a cross-section of ‘maritime’ writing. It is analysed using WordSmith analytical software (Scott, 2010), with the 100 million-word British National Corpus (BNC) as a reference corpus. Using the MTC, a list of keywords of specific salience within the maritime discourse has been compiled and, using frequency data, concordances and collocations, these MEs are described in detail and their use and form in the MTC and the BNC is compared. The study examines the transformation from ME to figurative use in the general discourse, in terms of form and metaphoricity. MEs are classified according to their metaphorical strength and their transference from maritime usage into new registers and domains such as those of business, politics, sports and reportage etc. A revised model of metaphoricity is developed and a new category of figurative expression, the ‘resonator’, is proposed. Additionally, developing the work of Lakov and Johnson, Kovesces and others on Conceptual Metaphor Theory (CMT), a number of Maritime Conceptual Metaphors are identified and their cultural significance is discussed