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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.
1

A novel methodology to investigate the performance of production line systems using an integrated product service system approach

Edakara, Sibson Dalgo January 2013 (has links)
Production Line Systems (PLS) are ubiquitous in today’s manufacturing industry. The need for enhanced efficiencies and higher throughput in such systems has increased their complexity and size that has made performance analysis challenging for practitioners. This thesis introduces a novel approach based on Product Service System (PSS) design and analysis which simplifies Production Line System study and identifies opportunities for performance improvement that can be quantified based on the hardware and maintenance system performance. The approach involves modelling and simulation techniques based on reliability engineering principles and systems thinking. In order to apply the principles of PSS approach to PLS, it is essential to draw a comparison between PLS and PSS, so as to take account of the differences while applying the new approach; a literature review has been carried out on PSS Design and Analysis, that identified the state of the art modelling and simulation techniques in PSS. Additionally, a separate literature review on maintenance system and production line was carried out. This enabled the PSS methodology to be applied to PLS by incorporating the differences. A systems thinking approach has been employed to create the static simulation model of the integrated production line system by means of schematic representations. Key improvement areas, identified from the static simulation model have been modelled dynamically to incorporate the stochastic behaviour of the system. All the dynamic models are developed using a Discrete Event Simulation platform. These models were supported by Monte Carlo Simulation, queuing principles, probabilistical and statistical methods pertinent to reliability engineering. The novel integrated simulation model consists of a production line model and a maintenance system model. The production line model simulates two types of failures in addition to the outages in the system: breakdowns and short stops. The maintenance system model simulates the maintenance actions in the production line by considering the resources availability, repair time, and resources travelling time amongst others. In addition, the maintenance model is capable of optimizing the preventive maintenance interval for maintainable failures for cost, availability and criticality while taking into account the maintenance effectiveness value from the failure data. The simulation model is validated using an industrial case study which consists of a large production line for beer. Sensitivity studies on the simulation model enabled the case study company to focus on strategies for throughput improvement by improving the reliability and maintainability, optimal resources allocation and maintenance interval optimization in targeted areas in the large and complex system. The model developed is generic and can easily be applied to analyse other industrial production line systems. It can also be used as a design tool for new production lines.
2

Lean Manufacturing Production Management Model using the Johnson Method Approach to Reduce Delivery Delays for Printing Production Lines in the Digital Graphic Design Industry

Gomero-Campos, A., Mejia-Huayhua, R., Leon-Chavarri, C., Raymundo-Ibañez, C., Dominguez, F. 06 April 2020 (has links)
Several factors compel graphic design companies to improve efficiency and competitiveness in their production lines. However, these companies are not prepared to take on this challenge, as they report delays in 20% of their deliveries, caused by high setup times, low machine availability, and poor work scheduling. In this context, this study proposes a new production management model fed by the interaction of lean manufacturing tools and the Johnson scheduling method. This model has been validated by direct application at the SISSA. The results obtained were the reduction of the setup time to 15 minutes, increased machine availability up to 24%, and an efficient scheduling of its tasks. All of these reduced the percentage of delivery delays from 20% to 6%.
3

Verifikace stavu reálné výrobní linky pomocí virtuální reality / Verification of the State of the Real Production Line using Virtual Reality

Tůma, Zdeněk January 2014 (has links)
The doctoral thesis focuses on the verification of state real work using virtual reality. Working with the theme dealt with more comprehensively, taking into account the sub-process of the production line design. From the assessment of the actual place where the future production line will be locate, through ergonomic, risk and other analysis. Furthermore, energy consumption of production line (electricity, air consumption, etc.) in real process. In analysing the readiness of virtual reality applications were selected for the following work augmented reality. The biggest advantage of augmented reality is the implementation of a virtual model and the opportunity to deal with the analysis in a real environment, which is particularly beneficial in the case of manufacturing companies. For the composition and optimization of the proposed solution was used a system approach. In the first phase of the solution was made analysis the current state of the work, which created requirements for the design of the new production line. This was followed by the preparation phase of construction in 3D, in this case, Autodesk Inventor. In this phase it was appeared to be advantageous to use the application of virtual reality, as in the design process leads to regular approval procedure of the experts team (management, design, quality, etc.), which puts on the readiness of the team high skills requirements. In this phase, the 3D design of the new production line was inserted into the support augmented reality application and outlined several opportunities to deal ergonomic and risk analysis. The proposed solution also follows the deployment in lean production area in the design phase, where it is possible to solve the analysis process using indirect methods of standard time (MOST). The result of the doctoral thesis is the extension options in designing and analysing production lines and machines in multidisciplinary teams. The proposed solution described in the thesis allows to simplification and reduce the overall time and costs of the overall process from design phase of production line to its commissioning.
4

ERROR DETECTION IN PRODUCTION LINES VIA DEPENDABLE ARCHITECTURES IN CONVOLUTIONAL NEURAL NETWORKS

Olsson, Erik January 2023 (has links)
The need for products has increased during the last few years, this high demand needs to bemet with higher means of production. The use of neural networks can be the key to increasedproduction without having to compromise product quality or human workers well being. This thesislooks into the concept of reliable architectures in convolutional neural networks and how they canbe implemented. The neural networks are trained to recognize the features in images to identifycertain objects, these recognition is then compared to other models to see which of them had the bestprediction. Using multiple models creates a reliable architecture from which results can be produced,these results can then be used in combinations with algorithms to improve prediction certainty. Theaim of implementing the networks with these algorithms are to improve the results without havingto change the networks configurations.
5

The evaluation of a production scheduling heuristic for production lines with changeover costs and dependent parallel processors

Dai, Bin January 1990 (has links)
No description available.
6

PROBLÈMES COMBINATOIRES EN CONFIGURATION DES LIGNES DE FABRICATION : ANALYSE DE COMPLEXITÉ ET OPTIMISATION / COMBINATORIAL PROBLEMS IN PRODUCTION LINES CONFIGURATION : COMPUTATIONAL ANALYSIS AND OPTIMIZATION

Kovalev, Sergey 23 November 2012 (has links)
L'objectif de la thèse est de créer et développer de nouvelles méthodes de résolution efficaces des problèmes combinatoires en configuration des lignes de fabrication. Deux problèmes ont été particulièrement étudiés: le problème d'équilibrage et de choix d'équipement pour des lignes dédiées et le problème de minimisation des coûts de changements de séries pour des lignes multi-produits. Une solution du premier problème consiste en une affectation admissible des ressources à un nombre de stations à déterminer de sorte que le coût total soit minimal. Afin de résoudre ce problème, nous l'avons réduit au problème de partition d'ensemble et l'avons résolu par des heuristiques gloutonnes et une méthode exacte de génération de contraintes. Les expérimentations sur différentes instances ont montré que la nouvelle approche de résolution surclasse les approches antérieures de la littérature en termes de qualité de solution et de temps de calcul. Pour le second problème deux critères sont considérés lexicographiquement : la minimisation du nombre de stations et la minimisation du coût de changement de séries. Nous avons examiné successivement les cas d'exécution parallèle et séquentielle des opérations. Des solutions approchées ont été trouvées par des heuristiques gloutonnes. Ensuite, nous avons proposé deux modèles de programmation linéaire en nombres entiers (PLNE) afin de trouver le nombre de stations minimal et ensuite d'obtenir le coût de changement de séries minimal. Les résultats des expérimentations sur ces nouveaux problèmes se sont avérés prometteurs à la fois en termes de qualité de solution et de temps de calcul. / The objective of this thesis is to create and develop new effective solution methods for production line configuration problems. Two problems were studied: the equipment selection and balancing problem for dedicated lines and the setup cost minimization problem for multi-product lines. A solution for the first problem consists in a feasible assignment of the resources to an unknown number of stations so that the total cost is minimized. In order to solve this problem, we reduced it to the set partitioning problem and solved it by greedy heuristics and an exact method of constraint generation. The computer experiments on different problem instances showed that the new solution approach outperforms the previous methods from the literature both in terms of solution quality and computational time. For the second problem two criteria were considered lexicographically: the minimization of the number of stations and the minimization of the total setup cost. We examined successively the cases with parallel and sequential execution of operations. Approximate solutions were found by greedy heuristics. Then, we proposed two integer programming models in order to obtain the minimal number of stations and then the minimal setup cost. The experimental results for this new problem proved to be promising both in terms of solution quality and computational time.
7

Models Of Synchronous Production Lines With No Intermediate Buffers

Cetinay, Hande 01 July 2010 (has links) (PDF)
Production lines with unreliable machines have received a great amount of attention in the literature. Especially, two-station systems have mostly been studied because such systems are easier to handle when compared to the longer lines. In literature, longer lines are usually evaluated by a decomposition algorithm, whereby the long line is partitioned into chunks of two-station lines. Decomposition algorithms require intermediate buffer storages of capacity at least two or three. The trends in modern manufacturing practices, on the other hand, such as the Toyota Production System, dictate that intermediate storages be eliminated. Our work studies multi-station lines with no intermediate storage. We develop software to automate the generation of transition probability matrices to allow the analysis of system behavior. The algorithm allows the use of software packages to handle computations and to solve for exact solutions. Long-run behavior is obtained via the algorithm developed in the computational environment MATLAB. The purpose is to analyze the system performance measures such as starvation and blockage times of stations, production rate and work-in-process. In addition, the production rate and the work-in-process measures over failure and repair probabilities are curve-fit to establish simple and useful empirical formulas for lines consisting three, four and five identical stations. Numerical analyses show that the proposed algorithm is effective for exact solutions and the suggested formulas are valid for approximate solutions.
8

Desenvolvimento de tubula??o em comp?sito polim?rico revestida externamente com poliuretano de alta densidade

Oliveira, Eugenio Onofre de 19 November 2010 (has links)
Made available in DSpace on 2014-12-17T14:06:56Z (GMT). No. of bitstreams: 1 EugenioOO_DISSERT.pdf: 4689753 bytes, checksum: 3bf8e997d1b94d1858f0a0c5652f05b0 (MD5) Previous issue date: 2010-11-19 / Pipelines for the transport of crude oil from the production wells to the collecting stations are named production lines . These pipes are subjected to chemical and electrochemical corrosion according to the environment and the type of petroleum transported. Some of these lines, depending upon the composition of the fluid produced, may leak within less than one year of operation due to internal corrosion. This work aims at the development of composite pipes with an external protecting layer of high density polyurethane for use in production lines of onshore oil wells, meeting operational requirements. The pipes were manufactured using glass fibers, epoxy resin, polyester resin, quartz sand and high density polyurethane. The pipes were produced by filament winding with the deposition of high density polyurethane on the external surface and threaded ends (API 15 HR/PM-VII). Three types of pipes were manufactured: glass/epoxy, glass/epoxy with an external polyurethane layer and glass/epoxy with an intermediate layer of glass fiber, polyester, sand and with an external polyurethane layer. The three samples were characterized by Scanning Electronic Microscopy (SEM) and for the determination of constituent content. In addition, the following tests were conducted: hydrostatic test, instant rupture, shorttime failure pressure, Gardner impact, transverse stiffness and axial tension. Field tests were conducted in Mossor? RN (BRAZIL), where 1,677 meters of piping were used. The tests results of the three types of pipes were compared in two events: after two months from manufacturing of the samples and after nine months of field application. The results indicate that the glass/epoxy pipes with an intermediate layer of fiber glass composite, polyester e sand and with an external layer of high density polyurethane showed superior properties as compared to the other two and met the requirements of pressure class, axial tensile strength, transverse stiffness, impact and environmental conditions, for onshore applications as production lines / As tubula??es para transporte de petr?leo dos po?os de produ??o at? a esta??o coletora s?o denominadas de linhas de surg?ncia . Essas tubula??es est?o sujeitas ? corros?o qu?mica e eletroqu?mica, de acordo com o ambiente e os tipos de petr?leo. Algumas dessas linhas, a depender da composi??o do petr?leo produzido falham, ?s vezes, com menos de um ano de opera??o, devido ? corros?o interna severa. Este trabalho objetiva o desenvolvimento de tubula??o em comp?sito revestida externamente com poliuretano de alta densidade, para aplica??o em linhas de surg?ncia de po?os de petr?leo onshore e que atenda ?s exig?ncias operacionais. Neste desenvolvimento foram empregados fibra de vidro, resina ep?xi, resina poli?ster, areia quartzosa e poliuretano (PU) de alta densidade. Os tubos foram produzidos pelos processos de enrolamento filamentar com deposi??o de PU na superf?cie externa e extremidades com rosca moldada (API 15 HR e PM-VII). Foram produzidas tr?s concep??es de tubos: vidro/ep?xi sem revestimento, vidro/ep?xi revestido com poliuretano de alta densidade e vidro/ep?xi coberto por um composto de fibra de vidro, poli?ster e areia, revestido externamente com poliuretano de alta densidade. Amostras das tr?s concep??es foram caracterizadas atrav?s da t?cnica de Microscopia Eletr?nica de Varredura (MEV), da determina??o do teor de vidro e resina, dos ensaios de rigidez e tra??o axial e dos testes hidrost?ticos, ruptura instant?nea, press?o de curta dura??o e impacto Gardner. Essa nova tecnologia foi testada no campo de produ??o em Mossor? RN, nos quais foram instalados 1.677 metros de tubos. Assim, os resultados dos ensaios e testes das tr?s concep??es de tubos foram comparados entre si em dois eventos: ap?s dois meses da fabrica??o das amostras e ap?s nove meses da aplica??o dos tubos em campo. Os dados indicaram que o tubo em comp?sito vidro/ep?xi, poli?ster e areia, revestido externamente com poliuretano de alta densidade , apresentou melhores resultados quando comparado aos outros dois, podendo ser usado na ind?stria de petr?leo em aplica??es onshore , como uma alternativa para a aplica??o em linhas de surg?ncia, atendendo ?s exig?ncias de classe de press?o, resist?ncia ? tra??o axial, rigidez, impacto e intemp?ries
9

Využití umělé inteligence pro optimalizaci výroby / The Use of Artificial Intelligence for Optimization of Production

Svoboda, Radovan January 2012 (has links)
This paper deals with the problem of optimization of a production plan by using genetic algorithms. It contains a brief overview of the principles behind genetic algorithms in scope of evolutionary algorithms and artificial intelligence in general. It also takes a closer look on the challenge of production planning and control and all activities connected to it. This is followed by description of the modification of genetic algorithms that needed to be done in order to implement it into a computer program, which is used to create and optimize the production plan, and is a result to the issue that this paper deals with. Incorporated is detailed escription of principles and functions of the program, that it offers to its users.
10

Guía de implementación del LPS (Last Planner System) para la etapa de acabados de un proyecto multifamiliar dirigido a los sectores económicos A y B ubicado en la ciudad de Lima / LPS (Last Planner System) implementation guide for the finishing phase of a multifamily project for economic sectors A and B located in Lima

Corilla Usquiano, Shirley Lizzeth, Pereda Torres, Andrea Natividad 01 December 2020 (has links)
El presente proyecto de investigación tiene por finalidad plantear una guía de implementación del Last Planner System, herramienta del Lean Construction, para la etapa de acabados de proyectos multifamiliares, el objetivo es que las empresas que deseen utilizar esta herramienta en sus proyectos de construcción puedan seguir los pasos sugeridos para garantizar una implementación exitosa. El proceso de construcción está marcado por un alto índice de variabilidad, el cual aumenta a medida que los interesados incrementan en número dentro de un solo proyecto. Esto nos lleva a concluir que, de todas las etapas de la construcción la que tendría el mayor índice de variabilidad sería la etapa de acabados. Actualmente, aproximadamente solo 25 empresas constructoras son miembros corporativos del Lean Construction Institute Perú; es decir, se encuentran alineadas con este sistema de gestión, esto a pesar de que el porcentaje de desperdicios que se originan en los proyectos de construcción es de aproximadamente 30% del monto total de la inversión. Para poder realizar el planteamiento de nuestra propuesta, primero desarrollamos los conceptos generales referidos al Lean Construction, Last Planner y los casos de éxito de proyectos que implementaron esta herramienta a nivel mundial y en nuestro país. Posteriormente, evaluamos las métricas y lecciones aprendidas de la fase de casco de dos proyectos ejecutados con sistemas de gestión distintos: tradicional y mediante el uso del Last Planner System. A partir de los resultados obtenidos, se planteó la guía de implementación del Last Planner System para la etapa de acabados. / The objective of this research project is to propose an implementation guide of the Last Planner System, a Lean Construction tool, for the finishing phase of multi-family projects, the objective is that companies that need to use this tool in their construction projects can follow suggested steps to ensure a successful implementation. The construction process is marked by a high rate of variability, which increases as the stakeholders increase in number within a single project. This leads us to conclude that, of all the construction stages, the one that would have the highest variability would be the finishing phase. Currently, only 25 construction companies are members of the Lean Construction Institute Peru; it is mean, they are aligned with this management system, even though the percentage of waste originating from construction projects is approximately 30% of the total investment amount. In order to carry out our proposal, we first develop the general concepts related to Lean Construction, Last Planner and the success stories of projects that implemented this tool worldwide and in our country. Subsequently, we evaluate the metrics and lessons learned from the structural phase of two projects executed with different management systems: traditional and using the Last Planner System. From the results obtained, we proposed the implementation guide of the Last Planner System for the finishing phase. / Trabajo de investigación

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