Dissertations / Theses on the topic 'Bottleneck theory'

The main theme of my dissertation is the analysis of several interactive decision making situations with multiple decision makers whose interests do not fully coincide. Non-cooperative game theory is invoked to carry on this analysis.The first chapter describes an experimental study of volunteer's dilemmas that evolve over time. Only a single volunteer is required for the public good to be provided. Because volunteering is costly, each prefers that some other players bear the full costs of volunteering. Reflecting on the observation that in many naturally occurring social dilemmas it is beneficial to volunteer earlier than later, I assume that the payoff to the volunteer and the (higher) payoff to each of the non-volunteers decrease monotonically over time. I derive symmetric and asymmetric subgame perfect equilibria. The experimental results provide little support to asymmetric equilibria in which only a single subject volunteers immediately. In comparison to the symmetric subgame perfect equilibrium, they show that subjects volunteer, on average, earlier than predicted.The second chapter explores a new type of online auction, called the unique bid auction, that has recently emerged on the Internet and gained widespread popularity in many countries. In a sharp contrast to traditional auctions, the winner in this class of auctions is the bidder who submits the lowest (highest) unique bid; all ties are discarded. I propose an algorithm to numerically compute the symmetric mixed-strategy Nash equilibrium solution and then conduct a series of experiments to assess the predictive power of the equilibrium solution. The experimental results show that the solution accounts quite well for the subjects' bidding behavior on the aggregate level, but not on the individual level.The last chapter proposes a discrete version of William Vickrey's model of traffic congestion on a single road with a single bottleneck. In my model, both the strategy space and number of commuters are finite. An algorithm similar to the one used in the second chapter is proposed to numerically calculate the symmetric mixed-strategy Nash equilibrium. The discrete model is then compared with the original continuous model of Vickrey in terms of the equilibrium solution and its implications.

We provide a formal mathematical definition of the Shortest Paths for All Flows (SP-AF) problem and provide many efficient algorithms. The SP-AF problem combines the well known Shortest Paths (SP) and Bottleneck Paths (BP) problems, and can be solved by utilising matrix multiplication. Thus in our research of the SP-AF problem, we also make a series of contributions to the underlying topics of the SP problem, the BP problem, and matrix multiplication. For the topic of matrix multiplication we show that on an n-by-n two dimensional (2D) square mesh array, two n-by-n matrices can be multiplied in exactly 1.5n ‒ 1 communication steps. This halves the number of communication steps required by the well known Cannon’s algorithm that runs on the same sized mesh array. We provide two contributions for the SP problem. Firstly, we enhance the breakthrough algorithm by Alon, Galil and Margalit (AGM), which was the first algorithm to achieve a deeply sub-cubic time bound for solving the All Pairs Shortest Paths (APSP) problem on dense directed graphs. Our enhancement allows the algorithm by AGM to remain sub-cubic for larger upper bounds on integer edge costs. Secondly, we show that for graphs with n vertices, the APSP problem can be solved in exactly 3n ‒ 2 communication steps on an n-by-n 2D square mesh array. This improves on the previous result of 3.5n communication steps achieved by Takaoka and Umehara. For the BP problem, we show that we can compute the bottleneck of the entire graph without solving the All Pairs Bottleneck Paths (APBP) problem, resulting in a much more efficient time bound. Finally we define an algebraic structure called the distance/flow semi-ring to formally introduce the SP-AF problem, and we provide many algorithms for solving the Single Source SP-AF (SSSP-AF) problem and the All Pairs SP-AF (APSP-AF) problem. For the APSP-AF problem, algebraic algorithms are given that utilise faster matrix multiplication over a ring.

The Internet has been more and more intensively used in recent years. Although network infrastructure has been regularly upgraded, and the ability to manage heavy traffic greatly increased, especially on the core networks, congestion never ceases to appear, as the amount of traffic that flow on the Internet seems to be increasing at an even faster rate. Thus, congestion control mechanisms play a vital role in the functioning of the Internet. Active Queue Management (AQM) is a popular type of congestion control mechanism that is implemented on gateways (most notably routers), which can predict and avoid the congestion before it happens. When properly configured, AQMs can effectively reduce the congestion, and alleviate some of the problems such as global synchronisation and unfairness to bursty traffic. However, there are still many problems regarding AQMs. Most of the AQM schemes are quite sensitive to their parameters setting, and these parameters may be heavily dependent on the network traffic profile, which the administrator may not have intensive knowledge of, and is likely to change over time. When poorly configured, many AQMs perform no better than the basic drop-tail queue. There is currently no effective method to compare the performance of these AQM algorithms, caused by the parameter configuration problem. In this research, the aim is to propose a new analytical model, which mainly uses discrete-time queueing theory. A novel transient modification to the conventional equilibrium-based method is proposed, and it is utilised to further develop a dynamic interactive model of responsive traffic and bottleneck queues. Using step-by-step analysis, it represents the bursty traffic and oscillating queue length behaviour in practical network more accurately. It also provides an effective way of predicting the behaviour of a TCP-AQM system, allowing easier parameter optimisation for AQM schemes. Numerical solution using MATLAB and software simulation using NS-2 are used to extensively validate the proposed models, theories and conclusions.

The aim of thesis is implemention the chosen techniques of lean management in the company named European Trailer Systems Ltd. based on the identification of bottlenecks. The theoretical part provides basic definitions of bottleneck, Theory of Constraints, Lean management and selected methods of lean management. The practical part begins with the company's European Trailer Systems s.r.o characteristic while describe the current situation. Furthermore, the practical part will focus on the identification of bottlenecks that occur in company European Trailer Systems Ltd. in the production process of sliding roofs, will be followed by a proposal to eliminate found bottlenecks with using methods of lean management and possibly their implementation.

Cell biology is a branch of science with a seemingly infinite abundance of interesting phenomena which are essential to our understanding of life and which may potentially drive the development of technology that improves our lives. Among the open ended questions within the field, an understanding of how gene networks are affected by limited cellular components is both broad and rich with interest. Common to all cellular systems are enzymes which perform many tasks within cells without which organisms could not remain healthy. Here are presented several explorations of enzymatic processing as well as a tool constructed for this purpose. More specifically, these works consider the effect of coupling of gene networks via competition for enzymes found within the cell. It is shown that a limitation on the number of available enzymes permits the formation of bottlenecks which drastically affect molecular dynamics within cells. These effects potentially afford cell behaviors that in part explain the impressive robustness of life to constantly fluctuating environments.
Ph. D.

Many companies today have to deal with business processes optimization, ongoing removal of system obstacles and identifying any bottlenecks laying on the way which are preventing us to reach our goals. I would like to show how we have dealt with similar problems in our case applied in the department of web application maintenance. In the first chapter I will introduce the basic information about the history, environment the company operate in and maintenance activities which are part of the process. Following with description all of the system obstacles and bottlenecks identified in the process and possible solutions or improvements for their elimination. In the last chapter I will present the achieved results after my executing of the proposed improvements and if the expectations have been met or not and what positive or negative influence it has brought.

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Fundação Oswaldo Cruz. Instituto de Tecnologia em Fármacos/Farmanguinhos. Rio de Janeiro, RJ, Brasil.
A busca por técnicas de gestão que possibilitem um melhor aproveitamento da capacidade instalada de plantas produtivas é o desafio constante de todos os gestores. A utilização da Teoria das Restrições (TDR) como ferramenta de gestão no ambiente produtivo deste estudo possibilitou evidenciar o uso racional dos equipamentos do parque fabril a partir da identificação dos gargalos dos processos produtivos dos produtos mapeados. O dimensionamento dos pulmões de proteção da restrição e de espaço demonstrou como é possível manter o fluxo constante de produção sem a necessidade de elevados estoques em processo entre os centros de trabalho que compõem os sistemas produtivos. A análise da capacidade global do sistema pode evidenciar os centros de trabalho com restrição de capacidade frente à demanda posta.
The quest for management techniques that enable a better utilization of productive capacity of plants is the constant challenge for all managers. Using the Theory of Constraints (TOC) as a management tool in the production environment of this study highlight the possible rational use of the equipment of the industrial park from the identification of “bottlenecks” of the production processes of products mapped. The sizing of the lungs to protect the space restriction and demonstrated how you can keep a steady flow of production without the need for high in-process inventories between the work centers that compose the productive systems. The analysis of the overall capacity of the system can highlight the work centers capacity constraint put forward the demand.

La investigación está orientada al diseño e implementación de un Modelo Integrado de Gestión de la Producción para la fabricación de llaves de cerradura, este modelo integra la teoría de restricciones para resolver los cuellos de botella y utiliza algunas herramientas de Lean Manufacturing para eliminar los desperdicios que se generan en los procesos que generan los cuellos de botella. El objetivo de la aplicación del modelo es el mejorar la productividad de la línea de fabricación de llaves de cerradura, la reducción de costos mediante la mejora de la eficiencia de sus procesos que permitan a la empresa ser más competitiva en el mercado. The research is focused on the design and implementation of an integrated management of production for the manufacture of keys lock model, this model integrates the theory of constraints to solve bottlenecks and used some tools of lean manufacturing to eliminate waste that is generated in the processes that create bottlenecks. The purpose of applying the model is to improve the productivity of the manufacturing line lock keys, reducing costs by improving the efficiency of their processes that enable the company to be more competitive in the market.

S tím, jak se neustále vyvíjejí nové technologie pro energeticky náročná průmyslová odvětví, stávající zařízení postupně zaostávají v efektivitě a produktivitě. Tvrdá konkurence na trhu a legislativa v oblasti životního prostředí nutí tato tradiční zařízení k ukončení provozu a k odstavení. Zlepšování procesu a projekty modernizace jsou zásadní v udržování provozních výkonů těchto zařízení. Současné přístupy pro zlepšování procesů jsou hlavně: integrace procesů, optimalizace procesů a intenzifikace procesů. Obecně se v těchto oblastech využívá matematické optimalizace, zkušeností řešitele a provozní heuristiky. Tyto přístupy slouží jako základ pro zlepšování procesů. Avšak, jejich výkon lze dále zlepšit pomocí moderní výpočtové inteligence. Účelem této práce je tudíž aplikace pokročilých technik umělé inteligence a strojového učení za účelem zlepšování procesů v energeticky náročných průmyslových procesech. V této práci je využit přístup, který řeší tento problém simulací průmyslových systémů a přispívá následujícím: (i)Aplikace techniky strojového učení, která zahrnuje jednorázové učení a neuro-evoluci pro modelování a optimalizaci jednotlivých jednotek na základě dat. (ii) Aplikace redukce dimenze (např. Analýza hlavních komponent, autoendkodér) pro vícekriteriální optimalizaci procesu s více jednotkami. (iii) Návrh nového nástroje pro analýzu problematických částí systému za účelem jejich odstranění (bottleneck tree analysis – BOTA). Bylo také navrženo rozšíření nástroje, které umožňuje řešit vícerozměrné problémy pomocí přístupu založeného na datech. (iv) Prokázání účinnosti simulací Monte-Carlo, neuronové sítě a rozhodovacích stromů pro rozhodování při integraci nové technologie procesu do stávajících procesů. (v) Porovnání techniky HTM (Hierarchical Temporal Memory) a duální optimalizace s několika prediktivními nástroji pro podporu managementu provozu v reálném čase. (vi) Implementace umělé neuronové sítě v rámci rozhraní pro konvenční procesní graf (P-graf). (vii) Zdůraznění budoucnosti umělé inteligence a procesního inženýrství v biosystémech prostřednictvím komerčně založeného paradigmatu multi-omics.

碩士
元智大學
工業工程與管理學系
95
The research is based on the theory of constraints and procedures of group technology to simplify the products mixed. Capacity planning is applied considering the factor of cycle time to display the stacking condition of bottleneck resources by Visual Basic algorithms, and then the impact of the changes of products mixed can be found out for optimal adjustment of products mixed. The objective of the research is to help PCB (Printed Circuit Board) factories decide products mixed in the shortest time during production planning stage for optimal capacity adjustment and preparation, and to avoid any changes of bottleneck resources made during the execution stage caused by inappropriate planning which can affect the output of production systems.

The simulation as a stand alone optimization tool of a complex system such as a vertical integrated mining operation, significantly over simplifies the actual picture of the system processes involved resulting in an unaccountable effort and resources being spent on optimizing Non Value Added (NA) processes. This study purposed to develop a discrete stochastic simulation-optimization model to accurately capture the dynamics of the system and to provide a structured way to optimize the Value Added (VA) processes. The mine operation model to be simulated for this study is designed as a hybrid level throughput model to identify the VA processes in a mining operation. This study also allows a better understanding of the impact of variation on the likelihood of achieving any given overall result. The proposed discrete stochastic simulation- optimization model provides the ability for a process manager to gain realistic understanding of what a process can do if some factors constraining the process were to be optimized i.e. to conduct what-if analysis. Another benefit of this approached technique is to be able to estimate dependable and reasonable returns on a large optimization related expenditure. The inputs into the model are the capability of the processes which are entered using various variables depending on how much information is available; simple inputs for least amount of information to detailed inputs for well known process to combinational inputs for somewhere in between. The process bottlenecks are identified and measured using the outputs of the model which include production output, severity of constraints, capacity constraints and cumulative bottleneck plots. Once a base case has been identified and documented then the inputs can be modified to represent the business initiatives and the outputs can be compared to the base case to evaluate the true value of the initiative.

碩士
中原大學
土木工程研究所
107
Freeway is the major roadway for providing mobility. To be effective as a corridor, it is important to use lane capacity efficiently. When there are aberrant driving behavior and heterogeneity in traffic flow, the efficiency of road performance tends to drop abruptly. Although aberrant driving behavior is not regularly seen all the time in traffic flow, their influence to the efficiency of traffic flow can’t be ignored: travel time will increase while each time aberrant driving behavior appear. In previous research, several researchers had studied moving bottlenecks of slow vehicles in the traffic flow for a while. Most of the works were based on simulation models according to traffic theories. In contrast to the theoretical development, the empirical studies had fallen far behind due to the difficulties of data collecting. This study aimed to explore the impact by slow vehicles based on the moving bottlenecks theory. The characteristics of slow vehicles were observed, identified and categorized on the survey section of Sun Yat-Sen Freeway. The video images from CCTV were used to build the methodology in measuring and analyzing slow vehicles as well as the moving bottleneck phenomenon. Followed by examining the characteristics of freeway flow for adjacent lanes. The issue of “wasteful” capacity was discussed thereafter.

碩士
國立高雄應用科技大學
工業工程與管理系碩士在職專班
104
In recent years, TOC theory of constraints by the use range of more and more for a wide. From the early manufacturing. Until the service sector now. For cost-effective enterprise has a great contribution.The TRIZ technology for innovation, mainly to solve engineering problems. In recent years, one after another to solve management problems rule. But after all, still rare. Because TRIZ innovation theory is by 39 parameters export 40 to solve engineering problems based law. In this study, after the TOC find bottlenecks. Cause analysis using the Figure due to a bottleneck analysis.After analyzing the causes of bottlenecks. The reason is divided into engineering problems and management issues. Engineering problems with 39 parameters TRIZ technology for innovation to solve the problem to find relevant laws. Coupled to elect suitable for solving engineering problems law in this study. However, management problems, resembling TRIZ principles.The cause of the problem as a management parameter. Then follow the relevant literature sorted out for solutions to problems. To solve the management problems. In this study, a semiconductor packaging and testing plant in the Case.Application of the above method to solve the problem. The results show: To solve the bottleneck problem of the production system to enhance overall output. Enhance the overall output can be reduced manpower needs. For the better deployment of personnel deployment. Keywords:Theory of Constraints, TRIZ technology for innovation, Improving production.

Dissertação de Mestrado em Engenharia e Gestão Industrial apresentada à Faculdade de Ciências e Tecnologia
O desempenho das linhas de produção de uma unidade fabril é determinante no sucesso alcançado pelas empresas. Para tal, qualquer processo de produção que vise o sucesso está diariamente sujeito a melhorias de forma a aumentar a eficiência e a diminuir os desperdícios, ferramentas de simulação como o software SIMUL8 têm visto a sua importância reforçada.O projecto desenvolvido consiste na análise e melhoria das operações realizadas na linha de produção de um dos tipos de rolha produzidos na Amorim Cork, a Twin Top. Com as dificuldades que a empresa apresenta em conseguir identificar os estrangulamentos nesta linha de produção, surge a necessidade de recorrer ao software de simulação, de forma a facilitar a visualização dos estrangulamentos do sistema. Assim sendo e recorrendo ao software SIMUL8, foi desenvolvido um modelo de simulação da linha de produção em questão. O modelo permite assim quantificar estrangulamentos previamente identificados.O objectivo deste trabalho passa por numa primeira etapa analisar algumas teorias recentes ligadas à primeira etapa da Teoria dos Constrangimentos – Identificação do estrangulamento, escolhendo a mais indicada, para depois fazer a sua aplicação no modelo de simulação criado para analisar a linha de produção Twin Top da Amorim Cork, identificando correctamente os bottlenecks do sistema.Os resultados obtidos, revelaram-se importantes ferramentas de análise e apoio à decisão para os processos de gestão de um sistema de produção, cada vez mais importante no dias actuais.
The performance of the production lines of a manufacturing unit is decisive in the success achieved by the companies. To this end, any production process aimed at success is daily subject to improvements in order to increase efficiency and decrease waste. Simulation tools such as SIMUL8 software have seen their importance reinforced.The project developed consists of the analysis and improvement of the operations carried out in the production line of one of the types of cork produced in Amorim Cork, the Twin Top. With the difficulties that the company presents in being able to identify the bottlenecks in this production line, it is necessary to use the simulation software, in order to facilitate the visualization of system bottlenecks. Thus, using a SIMUL8 software, a simulation model of the production line in question was developed. The model allows quantification of previously identified bottlenecks.The objective of this document is to analyze some recent theories related to the first stage of the Theory of Constraints - Identification of the bottleneck, choosing the most appropriate one, and then applying it to the simulation model created to analyze the production line, identifying the bottlenecks of the system.The obtained results proved to be important analysis tools and decision support for the management processes of a production system, increasingly each day the importance of this subject. After all, if we don't improve continuously our concorrents will reach us, and then leave us behind.