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  • 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.
31

Problems in Supply Chain Location and Inventory under Uncertainty

Hajizadeh Saffar, Iman 13 August 2010 (has links)
We study three problems on supply chain location and inventory under uncertainty. In Chapter 2, we study the inventory purchasing and allocation problem in a movie rental chain under demand uncertainty. We formulate this problem as a newsvendor-like problem with multiple rental opportunities. We study several demand and return forecasting models based on comparable films using iterative maximum likelihood estimation and Bayesian estimation via Markov chain Monte Carlo simulation. Test results on data from a large movie rental firm reveal systematic under-buying of movies purchased through revenue sharing contracts and over-buying of movies purchased through standard ones. For the movies considered, the model estimates an increase in the average profit per title for new movies by 15.5% and 2.5% for revenue sharing and standard titles, respectively. We discuss the implications of revenue sharing on the profitability of both the rental firm and the studio. In Chapter 3, we focus on the effect of travel time uncertainty on the location of facilities that provide service within a given coverage radius on the transportation network. Three models - expected covering, robust covering and expected p-robust covering - are studied; each appropriate for different types of facilities. Exact and approximate algorithms are developed. The models are used to analyze the location of fire stations in the city of Toronto. Using real traffic data we show that the current system design is quite far from optimality and provide recommendations for improving the performance. In Chapter 4, we continue our analysis in Chapter 3 to study the trade-off between adding new facilities versus relocating some existing facilities. We consider a multi-objective problem that aims at minimizing the number of facility relocations while maximizing expected and worst case network coverage. Exact and approximate algorithms are developed to solve three variations of the problem and find expected--worst case trade-off curves for any given number of relocations. The models are used to analyze the addition of four new fire stations to the city of Toronto. Our results suggest that the benefit of adding four new stations is achievable, at a lower cost, by relocating 4-5 stations.
32

A feature-based comparison of the centralised versus market-based decision making under lens of environment uncertainty : case of the mobile task allocation problem

Al-Yafi, Karim January 2012 (has links)
Decision making problems are amongst the most common challenges facing managers at different management levels in the organisation: strategic, tactical, and operational. However, prior reaching decisions at the operational level of the management hierarchy, operations management departments frequently have to deal with the optimisation process to evaluate the available decision alternatives. Industries with complex supply chain structures and service organisations that have to optimise the utilisation of their resources are examples. Conventionally, operational decisions used to be taken centrally by a decision making authority located at the top of a hierarchically-structured organisation. In order to take decisions, information related to the managed system and the affecting externalities (e.g. demand) should be globally available to the decision maker. The obtained information is then processed to reach the optimal decision. This approach usually makes extensive use of information systems (IS) containing myriad of optimisation algorithms and meta-heuristics to process the high amount and complex nature of data. The decisions reached are then broadcasted to the passive actuators of the system to put them in execution. On the other hand, recent advancements in information and communication technologies (ICT) made it possible to distribute the decision making rights and proved its applicability in several sectors. The market-based approach is as such a distributed decision making mechanism where passive actuators are delegated the rights of taking individual decisions matching their self-interests. The communication among the market agents is done through market transactions regulated by auctions. The system’s global optimisation, therefore, raise from the aggregated self-oriented market agents. As opposed to the centralised approach, the main characteristics of the market-based approach are the market mechanism and local knowledge of the agents. The existence of both approaches attracted several studies to compare them in different contexts. Recently, some comparisons compared the centralised versus market-based approaches in the context of transportation applications from an algorithm perspective. Transportation applications and routing problems are assumed to be good candidates for this comparison given the distributed nature of the system and due to the presence of several sources of uncertainty. Uncertainty exceptions make decisions highly vulnerable and necessitating frequent corrective interventions to keep an efficient level of service. Motivated by the previous comparison studies, this research aims at further investigating the features of both approaches and to contrast them in the context of a distributed task allocation problem in light of environmental uncertainty. Similar applications are often faced by service industries with mobile workforce. Contrary to the previous comparison studies that sought to compare those approaches at the mechanism level, this research attempts to identify the effect of the most significant characteristics of each approach to face environmental uncertainty, which is reflected in this research by the arrival of dynamic tasks and the occurrence of stochasticity delays. To achieve the aim of this research, a target optimisation problem from the VRP family is proposed and solved with both approaches. Given that this research does not target proposing new algorithms, two basic solution mechanisms are adopted to compare the centralised and the market-based approach. The produced solutions are executed on a dedicated multi-agent simulation system. During execution dynamism and stochasticity are introduced. The research findings suggest that a market-based approach is attractive to implement in highly uncertain environments when the degree of local knowledge and workers’ experience is high and when the system tends to be complex with large dimensions. It is also suggested that a centralised approach fits more in situations where uncertainty is lower and the decision maker is able to make timely decision updates, which is in turn regulated by the size of the system at hand.
33

La Dirección de Operaciones de Servicios (DOS)

Ríos Ramos, Franklin 16 July 2014 (has links)
Este artículo consiste en una revisión bibliográfica de los aportes teóricos que han ido surgiendo en el ámbito de los servicios. El primer objetivo de este artículo es determinar el estado actual de las investigaciones en la Dirección de Operaciones de Servicios, y el segundo es proponer una guía en este tema para futuras investigaciones. / This paper is a literature review about theoretical approaches that have emerged in the service field. The first purpose is to determine the state of the question in the research of Service Operations Management. The second is to offer a guide for future researches.
34

The application of practical geometry and the golden ratio in product design

Koh, Hyo Jin January 2015 (has links)
There have been numerous researchers who, over the years, have explored the relationship between the golden ratio and how it relates to the human perception of beauty. Although the golden proportion is one of the aesthetic characteristics contained in many masterpieces of art and design, it is still largely thought of as little more than an aesthetic guideline, that is, if indeed it is even being considered at all. This thesis asserts that golden proportion and practical geometric knowledge can be used as an extremely effective means of codifying the creative process, inspiring and influencing creative design decisions. This thesis is concerned with examining the application of practical geometric knowledge as an integral part of the design process. It also documents the development of the author's geometric refinement tools and discusses the results of their performance in testing by scrutinizing the opinions of design students and professional designers who both had their designs modified by the author's refinement tools. The relationship between geometric knowledge embedded in design classics and bestselling items was also examined. This thesis describes a mixed methods approach with multiple analyses, from which qualitative and quantitative data (about the implementation of applying geometric knowledge) was gathered via two geometry workshops, interviews with the professional designers, as well as an analysis of visual materials consisting of two hundred selected design examples. Based upon the process of employing geometric knowledge and its experiments, the thesis presents a descriptive analysis of the data to test theoretical propositions and draw conclusions about the value of applying practical geometry as design knowledge and as a practical tool for a design in the modern context. The significance of this thesis is that it elucidates upon the use of the golden ratio, and practical geometry as a practical design refinement tool, with the ability to transform the perception of practical geometry from being merely an aesthetic guideline which appears in masterpieces from the past, to a directly applicable practical design technique. The main contribution this thesis makes to the field of design practice is that it attempts to further understand the results achieved by codifying designing styles and design decisions, a process which can be described as objective rational knowledge in practice. This thesis frames individual design participants' perspectives of the golden ratio and the relationship between modern designs and the masterpieces of history. Thereby, hopefully providing a historical perspective and a modern context for the golden ratio. Further to that, it is the author's hope that this work will provide inspiration to today's designers, motivating them to begin implementing practical geometry into their designs and in the future generations of design education to come.
35

Implementing sustainability initiatives in business processes

Gallotta, Bruno January 2018 (has links)
Purpose – The sustainability topic has been receiving a growing importance in the corporate environment in recent years. More and more companies are adopting sustainability practices in all their organisational levels, operations and business process as a whole; however, they have still failed to achieve the anticipated goal. Existing roadmaps, frameworks and systems do not comprehensively support sustainable business transformation. This research proposes a four phases framework, based on BPM, to help organisations to implement sustainability practices in the organisation business processes and has verified it with industry/academic specialists and validated it in a local organisation focused on sustainability initiatives. Design/methodology/approach – A conceptual framework has been created, verified and validated. The framework is based on Business Process Management (BPM) principles, which was chosen because due its capability to work in a cross process way while providing the full control of the process performance. It was then verified using a Delphi study held with 21 specialists in Sustainable Operations Management from both academia and industry and validated using an action research study on a biomass company focused in the development of sustainable energy technologies that wished to improve the implementation of sustainability initiatives in its business processes and operations. Findings – It was identified that organisations still struggle to succeed the implementation of sustainability projects. The research outlined that the business process management (BPM) approach can be used as way to implement sustainability practices in an organisation’s business processes by using the conceptual framework. The benefits from this approach are the enablement of continuous process improvement, improvement of process quality; cost reduction; increase in the customer satisfaction; and better control 3 over process performance, which can be directly linked to the improvement of the sustainability improvement. Research limitations/implication – The main limitation of this research is the application of the framework in only one real-life scenario, which was expected due the research method chosen to validate it. Future work aims to apply the framework in different scenarios, in organisations with different sizes, different maturity level, different sector, and different locations. Further research will also investigate the symbiosis of the BPM approach with other management approaches, such as lean/green manufacturing, project management, and green supply chain and carbon footprint. In addition, in a further moment, once companies are familiarised with the project methodology, it is possible to create a centre of excellence (an area within the organisation with the best practices/ processes of the industry) in terms of sustainability bringing even more value, improving continuously and generating more innovation by the form of green reference process models. Practical implications – The proposed framework uses a Business Process Management (BPM) approach, which provides a systemic solution for the organisations adopt sustainability practices in their business processes.
36

Legalized Gambling: An Idea Whose Time Has Come

Gardner, Mark Stephen 01 March 1975 (has links)
No description available.
37

Evaluation of strategies for repeat procurement

Held, Christopher M. 12 December 2011 (has links)
For the past several decades, there has been a fundamental dispute between the appropriate mechanism for repeat procurement. On one hand, the supporters of Porter (1979) advocate a competitive setting where short-term contracts are used to increase buyer power and lower supplier prices. On the other hand, the supporters of Deming (1986) advocate the idea of long-term contracts to align buyer and supplier incentives. This trade-off between long-term and short-term contracts has fundamentally affected the practice of procurement, with most suppliers opting for hybrid strategies such as Incumbent Biasing: a strategy characterized by short-term contracts with frequent rebidding with an advantage given to the incumbent. This work examines this hybrid strategy to determine its effectiveness. First, we create an empirical model that identifies and measures the trade-offs between the Porter and Deming strategies. Using this model, we find that Incumbent Biasing has an impact on procurement performance via two mechanisms: first, Incumbent Biasing decreases bidding competitiveness in repeat procurement bidding, which decreases performance; second, Incumbent Biasing has a moderating effect where it improves incentive alignment between the buyer and supplier and improves procurement performance. We show that depending on the current contract design, the net effect of Incumbent Biasing on overall procurement performance can be either positive or negative. This is first work to empirically test the impact of Incumbent Biasing on procurement performance and the first to identify the positive and negative mechanisms by which this impact occurs. Using this research, managers will be able to identify their firm's position with regards to incentive alignment with their supplier to determine if Incumbent Biasing has a net positive effect for their firm. After identifying the impact of Incumbent Biasing on procurement performance, we contribute to the literature by testing this analysis through two additional extensions. First, using secondary data analysis we show that our construct for procurement performance is correlated with firm performance. We do this by comparing the answers to our procurement performance construct items to the change in gross margin of the publicly traded respondents in our study over time. This shows that our construct is not only reliable, but that procurement performance has a positive impact on overall firm performance. This is the first work to provide an empirical construct for procurement performance that is validated via secondary data analysis of firm performance. Second, we test a competing theory to Incumbent Biasing which is Multi-Sourcing: the strategy of spreading a contract to multiple suppliers to maintain competitiveness in bidding. Approximately $46\%$ of our sample identify as using both strategies simultaneously and we test for an impact between the two. We show that the two strategies to not impact each other and can be viewed independently. Subsequently, we test two Multi-Sourcing constructs in our model and find that there is no significant impact on bidding competitiveness from Multi-Sourcing. Subsequently, we examine the impact of repeatedly awarding a contract to a pool of bidders. In our model, one contract is bid repeatedly over time, resulting in bidders gaining information about their competitors' cost. The academic literature is mixed on how a buyer should approach this type of contract bidding interaction. On one hand, it is argued that establishing an awarding structure that favors the incumbent decreases the frequency of switching, and thus cost. On the other hand, it is argued that an awarding structure that favors the non-incumbent (entrant) bidders places competitive pressure on the incumbent and generates low margin bids. This issue is further complicated by the practice cited in the academic literature of ``defection', where entrant firms either perceive a bias or believe that their cost is uncompetitive and will not bid in future stages. We create a framework that explores the apparent contradictions in these recommendations and gives conditions when biasing toward the incumbent or entrant should be implemented. We first characterize bidders based on their effort to bid and their cost to supply the contract. We then show that in the case of low effort to bid and high cost for the entrant, entrant biasing is optimal; when the reverse is true incumbent biasing is optimal. Using the results from our analysis, we provide guidance to buyers facing a repeated procurement
38

Scania bus operations and supply chain management - two case studies

Wang, Lin, Åkerlund, Maja January 2014 (has links)
With its core competence on bus chassis, Scania determined in the mid-2000s to co-produce coach products with two external bus body manufacturers, Lahden Autokori and Higer. However, after a decade’s cooperation, well-functioning work processes were not established and problems still existed. With this study, problems within Scania’s operations system and Scania’s supply chain management strategies towards these two partners have been identified and illustrated, by applying an abductive research method. With this study it has been evidenced that Scania’s bus operations management is affiliated with truck and the truck operations system does not fit the request from the collaborations with Lahden Autokori and Higer. Moreover, it has also been shown that even though the relationship with these two partners is by nature long-term, Scania’s attitude has been characterized by short-term thinking. This ambiguous supply chain management strategy has been causing problems. Furthermore, aside from problems within operations system and supply chain management, the third studied area is organizational identity. Due to the fact that some organizational identity issues caused by reorganization have largely influenced both of the collaborations, the formation of these identity issues as well as the impacts on the cooperation has been studied. Finally, some recommendations for improvements have been made based on the findings of this study.
39

Development of collaborative green lean production systems

Kurdve, Martin January 2014 (has links)
This thesis deals with development of lean and green production systems from an action research point of view. The studies focus on Swedish-based automotive and vehicle industries and their aims to integrate sustainable thinking and environmental care into their operations management. Starting from operations management in manufacturing and corporate sustainable development, the research is built on how to integrate these two views into one production system. The systematic structure of a multiple-target improvement process with methodologies and tools designed to achieve the sustainability vision has been studied. Since lean as well as green production is based on the entire value chain, the research has gone beyond legal company limits and included the collaborative efforts between suppliers and customers in the value chain. The thesis includes six papers and describes approaches on how to implement integration, how to structure and integrate improvement management systems, how to set up an integrated monitoring and control system for the business and how to organise and redesign green lean tools and methodologies to support collaboration towards common targets. The results can be used for exploration and hypothesis formulation for further studies and development of integrated production systems and collaboration systems. The thesis helps answering how to integrate and implement company-specific green lean production systems.
40

Problems in Supply Chain Location and Inventory under Uncertainty

Hajizadeh Saffar, Iman 13 August 2010 (has links)
We study three problems on supply chain location and inventory under uncertainty. In Chapter 2, we study the inventory purchasing and allocation problem in a movie rental chain under demand uncertainty. We formulate this problem as a newsvendor-like problem with multiple rental opportunities. We study several demand and return forecasting models based on comparable films using iterative maximum likelihood estimation and Bayesian estimation via Markov chain Monte Carlo simulation. Test results on data from a large movie rental firm reveal systematic under-buying of movies purchased through revenue sharing contracts and over-buying of movies purchased through standard ones. For the movies considered, the model estimates an increase in the average profit per title for new movies by 15.5% and 2.5% for revenue sharing and standard titles, respectively. We discuss the implications of revenue sharing on the profitability of both the rental firm and the studio. In Chapter 3, we focus on the effect of travel time uncertainty on the location of facilities that provide service within a given coverage radius on the transportation network. Three models - expected covering, robust covering and expected p-robust covering - are studied; each appropriate for different types of facilities. Exact and approximate algorithms are developed. The models are used to analyze the location of fire stations in the city of Toronto. Using real traffic data we show that the current system design is quite far from optimality and provide recommendations for improving the performance. In Chapter 4, we continue our analysis in Chapter 3 to study the trade-off between adding new facilities versus relocating some existing facilities. We consider a multi-objective problem that aims at minimizing the number of facility relocations while maximizing expected and worst case network coverage. Exact and approximate algorithms are developed to solve three variations of the problem and find expected--worst case trade-off curves for any given number of relocations. The models are used to analyze the addition of four new fire stations to the city of Toronto. Our results suggest that the benefit of adding four new stations is achievable, at a lower cost, by relocating 4-5 stations.

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