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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.
301

Including workers with disabilities in flow shop scheduling / Incluindo trabalhadores com deficiência em flow shops

Carniel, Germano Caumo January 2015 (has links)
Pessoas com deficiências possuem muitas dificuldades em participar do mercado de trabalho, possuindo uma taxa de desemprego bem maior do que a média populacional. Isso motiva o estudo de novos modos de produção que permitam incluir essas pessoas com baixo custo operacional. Neste trabalho é feito um estudo sobre a inclusão de pessoas com deficiências em flow shops com o objetivo de minimizar o makespan. Como flow shops normalmente possuem poucas máquinas, o foco do estudo é na inserção de um e dois trabalhadores. O problema é definido, são propostos modelos matemáticos e uma solução heurística para resolvê-lo, assim como instâncias de teste realistas. Nos testes computacionais a performance dos modelos e da heurística é avaliada e a utilidade prática deste modelo de inclusão é analisada. Nós concluímos que o problema pode ser resolvido de forma satisfatória e que a inclusão de trabalhadores com deficiêcia emn flow shops é economicamente viável. / Persons with disabilities have severe problems participating in the job market and their unemployment rate is usually much higher than the average of the population. This motivates the research of new modes of production which allow to include these persons at a low overhead. In this work we study the inclusion of persons with disabilities into flow shops with the objective of minimizing the makespan. Since flow shops usually have only a few machines, we focus on the inclusion of one and two workers. We define the problem, propose mathematical models and a heuristic solution, as well as realistic test instances. In computational tests we evaluate the performance of the models and the heuristic, and assess the utility of such a model of inclusion. We conclude that the problem can be solved satisfactorily, and that including workers with disabilities into flow shops is economically feasible.
302

A study onshop sceduling problems / Um estudo sobre escalonamento de processos

Zubaran, Tadeu Knewitz January 2018 (has links)
Escalonamento de processos é um tipo de problema de otimização combinatória no qual devemos alocar máquinas à tarefas por períodos específicos de tempo. A literatura contém diversos estudos propondo técnicas para resolver modelos de escalonamento de processos como o job shop e o open shop. Esses modelos permitem que os passos no processo produtivo sejam ou completamente ordenados ou sem ordenação alguma. Com o aumento da complexidade das aplicações industriais no encontramos, mais recentemente, diversos trabalhos que propõe problemas de escalonamento de processos mais gerais para modelar mais precisamente os processos produtivos. O mixed shop, group shop e partial shop são exemplos de tais modelos. Nesse trabalho nós propomos uma busca tabu iterada para o partial shop, que é um modelo geral que inclui diversos modelos mais restritivos. Os componentes novos mais importantes da técnica são o gerador de solução inicial, a vizinhança e o limite inferior para a vizinhança. Em experimentos computacionais nós conseguimos demonstrar que a heurística genérica e única é capaz de competir, e as vezes superar, as técnicas de estado de arte desenvolvidas especificamente para partial, open, mixed e group shop. Algumas vezes uma máquina é o gargalo de um processo produtivo, e é replicada. Na literatura o caso das máquinas paralelas foi incluído em diversas extensões de problemas de escalonamento de processos. Nessa tese nós também propomos uma técnica para escalonar as máquinas paralelas, sem incluí-las explicitamente na representação do problema. Nós usamos técnicas gerais para os casos sem máquinas paralelas para produzir uma busca heurística tabu rápida, e estado da arte, para o caso do job shop com máquinas paralelas. / Shop scheduling is a combinatorial optimization type of problem in which we must allocate machines to jobs for specific periods time. A set of constraints defines which schedules are valid, and we must select one that minimizes or maximizes an objective function. In this work we use the makespan, which is the time the last job finishes. The literature contains several studies proposing techniques to solve shop problems such as the job shop and open shop. These problems allow the steps of the production processes to be either fully ordered or not ordered at all. With increasing complexity and size of industrial applications we find, more recently, several works which propose more general shop problems to model the production processes more accurately. The mixed shop, group shop and partial shop are examples of such problems In this work we propose an iterated tabu search for the partial shop, which is a general problem and includes several other more restrictive shop problems. The most important novel components of the solver are the initial solution generator, the neighbourhood, and the lower bound for the neighbourhood. In computational experiments we were able to show that the general partial shop solver is able to compete with, and sometimes surpass, the state-of-the-art solvers developed specifically for the partial, open, mixed and group shops. Sometimes a machine is a bottleneck in the production process, and is replicated. In the literature the parallel machines case has being included in several extensions of shop problems. In this thesis we also propose a technique to schedule the parallel machines heuristically, without including them explicitly in the representation of the problem. We use general techniques for the non-parallel machine cases to produce a fast tabu search heuristic results for the job shop with parallel machines.
303

Elektronický obchod v praxi / E-commerce in practice

DOŠEK, Jiří January 2012 (has links)
This graduation thesis deals with a detailed study of electronic commerce. The development process of e-commerce is described from the early ages of internet trading in the world and in the Czech Republic. The thesis also presents various types of electronic commerce and the practical part of the thesis provides practical examples of two enterprises and describes their life cycle from the foundation up to the effective functioning in practice. In the conclusion of my thesis, a suggestion of an innovative feature is created by a practical application, and is embedded into the internet trade.
304

Analýza nákupních podmínek Vimperska / Analysis of the buying terms at Vimperk

BRATHOVÁ, Jaroslava January 2012 (has links)
The aim of this thesis is to evaluate the purchasing conditions and geographical distribution of sales units in the Vimperk. Propose measures for improvement. Information was obtained by observing in each municipality Vimperk, interviewing and unstructured interviews. Subsequently, data were processed and evaluated.
305

Obchodování na internetu / E-Commerce

KUBIČKA, Tomáš January 2013 (has links)
Diploma thesis "E-commerce" aimed to create a suitable solution for marketing mix of the e-shop Levneelektro.cz. Based on performed analyzes I concluded that improvement of a communication with customers is very important for company ELEKTRA PV. I found that a crucial step for maintenance of competitiveness is the foundation of a loyalty program which is responsible for keeping customer loyalty. I have designed two different solutions of the loyalty program that are appropriate for the company.
306

Alocação e movimentação dinâmica de contêineres : um modelo integrado de escalonamento

Maranhão Filho, Éfrem de Aguiar January 2009 (has links)
A logística de contêiner vem aumentando sua participação em volume de cargas transportadas, tornando-se a parcela mais significativa do tráfego de mercadorias. Com isso, o gerenciamento dos altos custos envolvidos com a aquisição, manutenção, manipulação e transporte desses contêineres tornam-se um problema relevante para as organizações. As alocações dos contêineres cheios e vazios são comumente vistos como dois sistemas distintos e estáticos e não de forma intregada e dinâmica. Há um número restrito de trabalhos na literatura desenvolvendo heurísticas integrando os sistemas, porém não foi encontrada uma formulação ótima para o problema. Logo, a questão para a dissertação é quão próximo estão os resultados das heurísticas encontradas na literatura, para o problema da alocação de contêineres, dos resultados ótimos. O presente trabalho apresenta uma formulação matemática para o problema de alocação dinâmica, e integrada, para contêineres cheios e vazios. A formulação foi testada com diversos cenários, objetivando saber o limite computacional das instâncias para a formulação. Como o problema é um problema NP-Hard, heurísticas são comumente apresentadas na literatura. Demonstra-se como podem ser realizadas comparações entre os resultados das heurísticas e os resultados ótimos e visam a constatação da importância de uma formulação ótima para comparações. / Containers' Logistics has increased their importance in the goods transportion and nowadays, has the most important share of them. With that in mind, the management of high costs of acquisition, maintenance, manipulation and transportation of them became a significant problem to organizations. The problem of empty container allocation and load container allocation are commonly treated as two distinct, and static, systems, which means without integration and not dynamically. Just a couple of examples could be found of the two systems dynamically integrated, and no optimal model was found. So, the question here is how close heuristics' results are from the optimal results. A mathematical formulation is presented to the problem concerned with the integration and the dynamics associated to it. The formulation was tested with several scenarios to determine the maximum size that could be tested with optimal results, in an acceptable computacional time. Since the problem is a NP-Hard problem, heuristics approach are commonly used. Here is demonstrated how could be compare optimal solutions of the formulation and solutions from heuristics, and aim to demonstrate the significance of the optimal formulation.
307

Consumer poultry handling behaviors

Donelan, Amy K. January 1900 (has links)
Master of Science / Human Nutrition / Delores H. Chambers / Understanding how consumers handle poultry can highlight gaps in consumer knowledge and practice of food safety. Quantitative research provides only a partial image, whereas qualitative data is helpful in gaining a complete picture of a shopper's behaviors. The objective of this study was to determine what poultry product microbes could potentially be transferred during purchasing and home storage; using a shop-along observational technique to observe actual shopping, transporting, and storing behavior of consumers with raw poultry products. In 71% (n=97) of the situations observed there was no visible hand sanitizer or wipes in the meat section of the grocery store. Plastic bags could be found in the meat section 85% (n=97) of the time, which only 25% of shoppers (n=82) used the bag for their poultry products. During transportation, the consumer bagged the poultry separately from other products in 71% of the observations. A majority of shoppers (59%) stored poultry without using a plastic bag or other container. Overall, there needs to be an increase in food safety education on the handling of poultry during purchasing, transporting, and storage.
308

Estudo dos efeitos da oscilação do molde na produção de tarugos por lingotamento contínuo / Effects of mold oscillation on continuously cast billets

Gonçalves, Camilla Gandine [UNESP] 02 August 2016 (has links)
Submitted by Camilla Gandine Gonçalves null (camilla.gandine@yahoo.com.br) on 2016-08-23T02:19:17Z No. of bitstreams: 1 TESE_CAMILLA GANDINE GONCALVES_22082016.pdf: 2592904 bytes, checksum: 8d046da87d339892a84ca5bd145a19ec (MD5) / Approved for entry into archive by Ana Paula Grisoto (grisotoana@reitoria.unesp.br) on 2016-08-24T17:36:53Z (GMT) No. of bitstreams: 1 goncalves_cg_dr_guara.pdf: 2592904 bytes, checksum: 8d046da87d339892a84ca5bd145a19ec (MD5) / Made available in DSpace on 2016-08-24T17:36:53Z (GMT). No. of bitstreams: 1 goncalves_cg_dr_guara.pdf: 2592904 bytes, checksum: 8d046da87d339892a84ca5bd145a19ec (MD5) Previous issue date: 2016-08-02 / O objetivo deste trabalho é estudar a oscilação do molde na produção de tarugos por lingotamento contínuo e a sua consequência na qualidade do produto final, através de modelamento matemático. A oscilação do molde origina um defeito superficial conhecido como marca de oscilação. O modelo da formação das marcas considera três partes: térmica, mecânica dos fluidos e mecânicos dos sólidos. São consideradas as fases sólida e pastosa, até certa fração sólida, como resistentes aos esforços advindos da oscilação, e que o raio do menisco é não estacionário. Verifica-se que o aumento do curso de oscilação do molde aumenta a profundidade das marcas de oscilação, o aumento da frequência de oscilação tem comportamento ascendente até um ponto máximo, seguido de descendente, enquanto o aumento da velocidade de lingotamento aumenta a profundidade das marcas, desde que a frequência e curso sejam mantidos constantes. O estripamento negativo aparenta ser função de todas as demais variáveis de processo. / This work aims to study the mold oscillation in continuous casted billets and its consequence on the final product quality throw mathematical modeling. The mold oscillation causes a surface defect known as oscillation marks. The model of oscillation marks formation is divided in three parts: thermal, fluid mechanics and mechanics of solids. Two phases, solid and mushy steel above to a certain solid fraction are considered as having mechanical strength, and the meniscus radius is non stationary. It appears that the increasing in stroke increases the depth of the oscillation marks, increasing the oscillation frequency is upward behavior up to a maximum point, followed by descending, while increasing the casting speed increases the depth of oscillation marks, if frequency and stroke is kept constant. The negative strip time appears to be a function of all other process variables.
309

A study onshop sceduling problems / Um estudo sobre escalonamento de processos

Zubaran, Tadeu Knewitz January 2018 (has links)
Escalonamento de processos é um tipo de problema de otimização combinatória no qual devemos alocar máquinas à tarefas por períodos específicos de tempo. A literatura contém diversos estudos propondo técnicas para resolver modelos de escalonamento de processos como o job shop e o open shop. Esses modelos permitem que os passos no processo produtivo sejam ou completamente ordenados ou sem ordenação alguma. Com o aumento da complexidade das aplicações industriais no encontramos, mais recentemente, diversos trabalhos que propõe problemas de escalonamento de processos mais gerais para modelar mais precisamente os processos produtivos. O mixed shop, group shop e partial shop são exemplos de tais modelos. Nesse trabalho nós propomos uma busca tabu iterada para o partial shop, que é um modelo geral que inclui diversos modelos mais restritivos. Os componentes novos mais importantes da técnica são o gerador de solução inicial, a vizinhança e o limite inferior para a vizinhança. Em experimentos computacionais nós conseguimos demonstrar que a heurística genérica e única é capaz de competir, e as vezes superar, as técnicas de estado de arte desenvolvidas especificamente para partial, open, mixed e group shop. Algumas vezes uma máquina é o gargalo de um processo produtivo, e é replicada. Na literatura o caso das máquinas paralelas foi incluído em diversas extensões de problemas de escalonamento de processos. Nessa tese nós também propomos uma técnica para escalonar as máquinas paralelas, sem incluí-las explicitamente na representação do problema. Nós usamos técnicas gerais para os casos sem máquinas paralelas para produzir uma busca heurística tabu rápida, e estado da arte, para o caso do job shop com máquinas paralelas. / Shop scheduling is a combinatorial optimization type of problem in which we must allocate machines to jobs for specific periods time. A set of constraints defines which schedules are valid, and we must select one that minimizes or maximizes an objective function. In this work we use the makespan, which is the time the last job finishes. The literature contains several studies proposing techniques to solve shop problems such as the job shop and open shop. These problems allow the steps of the production processes to be either fully ordered or not ordered at all. With increasing complexity and size of industrial applications we find, more recently, several works which propose more general shop problems to model the production processes more accurately. The mixed shop, group shop and partial shop are examples of such problems In this work we propose an iterated tabu search for the partial shop, which is a general problem and includes several other more restrictive shop problems. The most important novel components of the solver are the initial solution generator, the neighbourhood, and the lower bound for the neighbourhood. In computational experiments we were able to show that the general partial shop solver is able to compete with, and sometimes surpass, the state-of-the-art solvers developed specifically for the partial, open, mixed and group shops. Sometimes a machine is a bottleneck in the production process, and is replicated. In the literature the parallel machines case has being included in several extensions of shop problems. In this thesis we also propose a technique to schedule the parallel machines heuristically, without including them explicitly in the representation of the problem. We use general techniques for the non-parallel machine cases to produce a fast tabu search heuristic results for the job shop with parallel machines.
310

Posílení efektivity projektu internetového obchodu / Improve efficiency of project of e-shop

NOVOTNÁ, Renata January 2009 (has links)
The objective of this thesis is to strengthen competitiveness of iProdukční s.r.o by means of application of marketing strategies and presentation of results on its adapted website. The company operates an interactive portal aukce.mimiweb.cz.

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