43 research outputs found
Uma contribuição para o escalonamento da produção baseado em métodos globalmente distribuídos
Tese Doutoramento em Engenharia e Gestão IndustrialO escalonamento da produção é uma função que pode contribuir fortemente para a capacidade
competitiva das empresas produtores de bens e serviços. Pode, simplificadamente ser definido com
a função de afectar tarefas a meios de produção ao longo do tempo. Resolver um problema de
escalonamento envolve várias actividades. Primeiro é necessário descrever o problema e identificálo
numa dada classe. Depois, é necessário encontrar um método eficiente apropriado à sua resolução
e usá-lo para resolver o problema, disponibilizando os dados necessários e tratando os resultados de
forma conveniente.
Muitas vezes as pessoas envolvidas na resolução de problemas de escalonamento não conhecem os
métodos ou não sabem como ter acesso a eles, ou mesmo não sabem como formalmente identificar
o problema numa classe.
O trabalho de investigação aqui relatado pretende contribuir para facilitar a compreensão dos
problemas e melhorar o processo de escalonamento na indústria, apresentando contribuições no
domínio do escalonamento da produção em duas envolventes principais: uma a um nível teórico,
conceptual e outra ao nível prático da resolução de problemas. Ao nível conceptual contribui para
uma ontologia de problemas de escalonamento da produção e conceitos relacionados, tais como
ambiente de escalonamento de produção, tarefas, postos de trabalho, métodos de resolução,
implementações e soluções, providenciando um enquadramento comum para a compreensão a
partilha de conhecimento acerca destes conceitos. Ao nível da resolução dos problemas de
escalonamento, faz-se um estudo alargado sobre a forma da sua resolução. Na concretização deste
estudo desenvolve-se um sistema web de apoio ao escalonamento da produção (SWAEP), cuja
arquitectura e funcionalidades são implementadas através de um demonstrador desenvolvido e
implementado com base na tecnologia XML e na arquitectura de rede P2P, formando uma
comunidade virtual de escalonamento da produção. Este demonstrador permite testar e avaliar a
viabilidade das premissas e hipóteses subjacentes a este trabalho de investigação das quais é de
realçar a pretensão de melhorar o processo de escalonamento de empresas industriais usando um sistema web de escalonamento da produção baseados em conhecimento globalmente distribuído e acedido via Internet e intranets.
Esta filosofia de suporte ao escalonamento industrial pode considerar-se inovadora, porquanto difere das soluções existentes nas empresas ou actualmente acessíveis via Internet, por serem predominantemente centralizadas e pouco abrangentes.Production Scheduling is an important function strongly contributing to the competitiveness of
industrial and service companies. It may be defined as the activity of allocating tasks to production
resources, during a certain period of time. Solving a production scheduling problem involves
several activities, starting with a clear description of it, with its identification within a class of
problems. The next task is to find at least one suitable and efficient method, if it exists, for solving
the problem, followed by running implementations of the method with the required set of input data
and getting results in some adequate or desirable form. Often the people who have the problem to
solve don’t know about the methods or even the existing problem classification.
The research work here reported aims at facilitating the understanding of scheduling problems and
improving the scheduling processes in companies. For this it presents contributions at two
complementary levels. First, at the conceptual level it contributes for an ontology of scheduling
problem related concepts, such as problem, scheduling environment, job, processor, method,
implementation and solution, providing a common setting for knowledge sharing about these
concepts. At the problem resolution level it comprises a web based scheduling system, with a
distributed knowledge base, for sharing knowledge about scheduling and for aiding to solve
scheduling problems. A demonstrator of this system is developed, implementing its architecture and
functionalities, using XML technology and a P2P computer network forming a virtual community
for production scheduling. The demonstrator is used for testing and evaluating the main idea behind
this work namely that of sharing methods globally available for improving the scheduling process at
companies by accessing these methods through the Internet. This scheduling strategy can be
considered innovative having into account that most of the available scheduling systems are mostly
centralized systems implemented at companies or accessed through the Internet and of limited
scope
A document-oriented web-based application for supporting collaborative product development
Innovation is a creative process strongly associated with development and deployment of new products, i.e., goods and services. This is essential in the global economy of today for sustainability and success of companies. Good collaboration between those involved in new product development is an essential requisite for this success. Such collaboration, which involves not only company stakeholders but also suppliers and customers, requires easy access to necessary data and agile communication and sharing of relevant information, which is distributed in a network of resources and users. Hence, web-based applications, decentralized repositories and databases are used to store and manage product and process development information. For meeting these new product development requirements Internet based collaborative tools and services must be applied. The use of web services is important in product development, helping the integration of data and knowledge bases and also processes and application interactions. This paper reports on work for managing product and process information, as well as documentation generation, throughout the product development process cycle in an Internet based collaborative environment. The information concerned includes product and process information, as well as product development history. One important aspect deals with web based restoring decisions and options made along the product design and development cycle, including product revisions and/or versions manipulation. The research work, focus is on the development of a document-oriented web-based application using Apache CouchDB technology and REST web services. The proposed application is described and the main functionalities are illustrated through some examples of use.Universidade do MinhoFundação para a Ciência e a Tecnologia (FCT
Mathematical and computational modelling in matlab for the study of an ORC solar system
The main objective of this paper was to acquire the necessary thermodynamic knowledge in order to perform a thermodynamic and economic analysis of a solar ORC system of capacity of 10KW. For this, a model and computer program were developed in Matlab R2008a, version 7.6.0, which analyses the efficiency of the collector based on the gross solar radiation introduced and the efficiency of the ORC cycle against the power of the respective radiation. Based on the behaviour of the collector and the ORC cycle, the program returns as outputs the area and quantity of manifold required for the desired power. Through this study it can be concluded that for the best scenario, the collector area required is 1044.1 m2 and collector 590 respectively. The annual profit is 48360€/year and an 8 year payback for the initial investment with the vacuum tube collectors.This work has been supported by COMPETE: POCI01-0145-FEDER-007043 and FCT – Fundação para a Ciência e Tecnologia within the Project Scope: UID/CEC/00319/2013info:eu-repo/semantics/publishedVersio
Definition of a collaborative working model to the logistics area
In today’s global economy, the collaboration has become an essential requirement for effective functioning of society. The emergence of Web 2.0 has been indicated as a set of tools to simplify collaboration. The aim of this project is to create an online enterprise community for all logistics employees of Bosch Car Multimedia division in the Bosch Group, for an internal collaboration of the entire Bosch Group based on an IBM Connections platform: Bosch Connect. An additional concern, collected throughout the project, was to bring employees to join the platform, making it a tool of your daily work. Through interviews and a surveys was possible to take the communication and collaboration needs of the target community and thus carry out its construction, based on Design for Six Sigma methodology. As a final result we created the community "Be One Logistics". Despite the limited time to achieve the results (4 months), it was possible to observe an adherence of 71% of the target population. Despite the relatively low number of users (41.7%), some important contributions were made in terms of content updates, and has been a major update in the wiki application, with 77% of the total generated content. Concerning the accesses, there was a balance between the uses of the various applications.This work was supported by FCT “Fundação para a Ciência e a Tecnologia” under the program: PEst2015-2020.info:eu-repo/semantics/publishedVersio
Improving productivity and standard time updating in an industrial company - A case study
Today’s marketplace imposes ever-tightening product pricing and quality requirements, shorter delivery times, and increasingly customized products. With increasing competition in today’s global market, companies are increasingly pressured to improve the performance of their production systems in order to be more competitive and improve market share. In order to try to satisfy these requirements several companies seek for the application of methodologies that may enable them to respond to these challenges, such as the ones based on the Lean Manufacturing philosophy. In this work standard times of four extruders are determined and updated in the context of setup time’s analysis and minimization in a company, in Portugal. First, a diagnosis is made to the tire floor extrusion process in order to evaluate all of its inefficiencies with the greatest impact on the production process, after the standard time of each extruder is analysed and updated through an extended approach which does also consider setup times reduction, along with the production times, for reaching a higher process optimization rate and productivity in the underlying production system.This work has been supported by COMPETE: POCI01-0145-FEDER-007043 and FCT – Portuguese Foundation for Science and Technlology.info:eu-repo/semantics/publishedVersio
Scheduling Single-Machine Problem Oriented by Just-In-Time Principles - A Case Study
Developments in advanced autonomous production resources have increased the interest in the Single-Machine Scheduling Problem (SMSP). Until now, researchers used SMSP with little to no practical application in industry, but with the introduction of multi-purpose machines, able of executing an entire task, such as 3D Printers, replacing extensive production chains, single-machine problems are becoming a central point of interest in real-world scheduling. In this paper we study how simple, easy to implement, Just-in-Time (JIT) based, constructive heuristics, can be used to optimize customer and enterprise oriented performance measures. Customer oriented performance measures are mainly related to the accomplishment of due dates while enterprise-oriented ones typically consider other time-oriented measures.The authors wish to acknowledge the support of the Fundação para a Ciência e Tecnologia (FCT), Portugal, through the grant “Projeto Estratégico – UI 252 – 2011–2012” reference PEst-OE/EME/UI0252/2011 and FCOMP-01-0124FEDER-PEst-OE/EEI/UI0760/2014info:eu-repo/semantics/publishedVersio
The tool supporting decision making process in area of job-shop scheduling
Today most manufacturing companies from machine building industry are operating in single unit or short-run production which is very complex in terms of decision making processes in production planning area. The difficulty in decision making in the area of scheduling is caused by the necessity of analy sing multiple factors and evaluating various scheduling options due to numerous criteria. The article presents the author’s tool supporting decision making in the area of job-shop scheduling. The tool introduced in the article enables scheduling based on author’s priority rule allowing maximum usage of the most loaded resource (known as critical resource), which determines efficiency of the produc tion system. The tool has been designed and verified as a part of PhD dissertation research.This work has been supported by COMPETE: POCI-01-0145-FEDER-007043 and FCT – Fundação para a Ciência e Tecnologia within the Project Scope: UID/CEC/00319/2013.info:eu-repo/semantics/publishedVersio
Web-based decision support system for industrial operations management
To maintain sustainability in today’s’ global economy industrial companies must have well managed systems and operations to keep up with competition. For this they can take advantage of using Web and Internet based technologies. Such can be achieved by accessing good management resources and methods through the Internet which otherwise would not be available and, at the same time, take advantageous of collaboration provided by networks of partners and users. Due to operations management complexity when a company does not have access to good algorithms it usually draws upon simple and empirical procedures whose quality of solutions provided tends to be poor. This is a situation that can be avoided if companies have easy access to good operations management algorithms or services. This can be possible because a pool of knowledge on industrial operations management, which has been developed by academia and industry over the years, can be made available, through the Internet, to a large community of users. This idea is explored towards development of a web-based system for Industrial Operation Management, based on a P2P network of operations management algorithms providers and users. Thus, the paper describes a web system for aiding the resolution of Operations Management problems through collaboration based on a network of distributed resources and users, web services and other Internet technology. The system adopts a P2P network architecture to create and enable a decentralized and global industrial operations management environment. It includes a set of functionalities accessed through the P2P network, which holds algorithms for solving different types of Operations Management problems. The algorithms are selected through a user-friendly interface, which is automatically generated for each specific problem context, including loading existing XML problem data documents, and searching and running algorithms on the peers belonging to the P2P network.Universidade do MinhoFundação para a Ciência e a Tecnologia (FCT
Collaborative portal for supporting manufacturing resources selection in a global market
In the last decades the manufacturing industry has shifted from largely single location centralized manufacturing towards networked manufacturing spread over multiple sites. Companies have either established new production sites in multiple locations or established strategic partnerships to respond to market changes more rapidly as well as for more efficient and effective sharing of resources, through the so-called integrated manufacturing systems environments. In this context, proper collaboration among different locations and/or partners becomes more critical. Thus, development of appropriate integrated tools, to enable clients or network partners to accurately select appropriate manufacturing resource from the widened global market context, becomes emergent. Therefore, this work is aimed at providing a contribution to maximize overall benefit of businesses, in the context of a networked scenario, and subject to a set of configurations and restrictions on part of the manufacturing resources providers and searchers. Thus, the authors propose a collaborative portal to enable to perform a better manufacturing resources selection, based on technologies integration for supporting accurate orders processing.The authors wish to acknowledge the support of the Foundation for Science and Technology – FCT, under the scope of the financed Project with reference: PEst20152020, as well as the FCT Doctoral grant referenced SFRH/BD/62313/2009.info:eu-repo/semantics/publishedVersio
Purchase management improvement in a TV company from the industry district of Manaus (PIM)
All rights reserverd. Continuous improvement in quality of products and processes offered by an organization can support companies keep it long in this competitive and dynamic business environment. Therefore, the interaction between the university, government, and Industry (the triple helix) is the opportunity for a Technology Company as TV’s industry to have innovation and new studies developed frequently. This research, studies the improvements of material purchases process to increase knowledge in the TV Purchasing Department inside an Industry from the Industrial District of Manaus, Brazil (PIM) which deals with high technology on their products and must have agility to be the first option to the customers. During the research a checklist was applied to employees from purchasing department and was observed that there was a frequent participation from quality sector in the resolution of the procurement process and that has proven to be positive in the management process. These are facilitators on a daily developers, customers and suppliers.This work has been supported by COMPETE: POCI-01-0145-FEDER-007043 and FCT – The Foundation for Science and Technology within the Project Scope: UID/CEC/00319/2013.info:eu-repo/semantics/publishedVersio