4,255 research outputs found

    Modeling and Solving Flow Shop Scheduling Problem Considering Worker Resource

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    In this paper, an uninterrupted hybrid flow scheduling problem is modeled under uncertainty conditions. Due to the uncertainty of processing time in workshops, fuzzy programming method has been used to control the parameters of processing time and preparation time. In the proposed model, there are several jobs that must be processed by machines and workers, respectively. The main purpose of the proposed model is to determine the correct sequence of operations and assign operations to each machine and each worker at each stage, so that the total completion time (Cmax) is minimized. Also this paper, fuzzy programming method is used for control unspecified parameter has been used from GAMS software to solve sample problems. The results of problem solving in small and medium dimensions show that with increasing uncertainty, the amount of processing time and consequently the completion time increases. Increases from the whole work. On the other hand, with the increase in the number of machines and workers in each stage due to the high efficiency of the machines, the completion time of all works has decreased. Innovations in this paper include uninterrupted hybrid flow storage scheduling with respect to fuzzy processing time and preparation time in addition to payment time. The allocation of workers and machines to jobs is another innovation of this article

    Energy aware hybrid flow shop scheduling

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    Only if humanity acts quickly and resolutely can we limit global warming' conclude more than 25,000 academics with the statement of SCIENTISTS FOR FUTURE. The concern about global warming and the extinction of species has steadily increased in recent years

    Scheduling with subcontracting options

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    Department of Logistics2008-2009 > Academic research: refereed > Publication in refereed journalAccepted ManuscriptPublishe

    Integrating labor awareness to energy-efficient production scheduling under real-time electricity pricing : an empirical study

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    With the penetration of smart grid into factories, energy-efficient production scheduling has emerged as a promising method for industrial demand response. It shifts flexible production loads to lower-priced periods to reduce energy cost for the same production task. However, the existing methods only focus on integrating energy awareness to conventional production scheduling models. They ignore the labor cost which is shift-based and follows an opposite trend of energy cost. For instance, the energy cost is lower during nights while the labor cost is higher. Therefore, this paper proposes a method for energy-efficient and labor-aware production scheduling at the unit process level. This integrated scheduling model is mathematically formulated. Besides the state-based energy model and genetic algorithm-based optimization, a continuous-time shift accumulation heuristic is proposed to synchronize power states and labor shifts. In a case study of a Belgian plastic bottle manufacturer, a set of empirical sensitivity analyses were performed to investigate the impact of energy and labor awareness, as well as the production-related factors that influence the economic performance of a schedule. Furthermore, the demonstration was performed in 9 large-scale test instances, which encompass the cases where energy cost is minor, moderate, and major compared to the joint energy and labor cost. The results have proven that the ignorance of labor in existing energy-efficient production scheduling studies increases the joint energy and labor cost, although the energy cost can be minimized. To achieve effective production cost reduction, energy and labor awareness are recommended to be jointly considered in production scheduling. (C) 2017 Elsevier Ltd. All rights reserved

    AN AGENT-BASED COOPERATIVE MECHANISM FOR INTEGRATED PRODUCTION AND TRANSPORTATION PLANNING

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    This paper presents a decentralized cooperative economic scheduling mechanism for a supply chain environment. For this purpose, we design autonomous agents that minimize the production or transportation costs and outsourcing costs incurred by the external execution of a task. The decentralized cooperative scheduling approach comprises two parts: the individual optimization an agent\u27s local schedule and the cooperative contract optimization, either by outsourcing the task or by (re-)contracting the release time and due time with the contract partners aiming to maximize their total profits. A negotiation mechanism based on trust accounts is employed to protect the agents against systematic exploitation by their partners

    The effective management of customer orders received by a pharmaceutical manufacturer

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    There is a great need for a pharmaceutical manufacturer to provide its customers with the right product at the right time, place and price and also to deliver the product in the right quantity and quality. Should pharmaceutical customers not receive their orders on time from the pharmaceutical manufacturer, the customers might face out-of-stock situations. As a result, the patients or customers might turn to an alternative product from a different pharmaceutical manufacturer, which has the required stock readily available. This could lead to loss in sales and even death amongst its customers. The main objective of this study was to determine the key factors that form part of the demand and operations planning strategies to ensure that these factors are in place to effectively manage and execute the supply chain and logistics processes to reduce possible out-of-stock situations amongst its customers. As a starting point to the study, an analysis was performed based on the review of relevant research and literature from various text books, journals, publications, as well as internet sources. The literature study covered various aspects such as demand planning, production planning, the use of different demand and operations planning strategies, as well as the importance of continuous internal and external customer service levels to ensure that customer orders are delivered on time. The analysis of the literature review was used to establish a theoretical basis for the design and structure of the questionnaire that was used as a research instrument in this study. A survey was conducted amongst the employees that are responsible for executing the supply chain and logistics processes within Aspen Pharmacare. These employees resided within the three main departments of the pharmaceutical manufacturer, namely, the Demand and Operations Planning, Production and Packing, as well as the Warehouse and Distribution departments. Each question posed in the questionnaire related to the role of each employee within these departments that are responsible for the logistics processes within Aspen Pharmacare. The empirical results from the study indicated that the respondents were in support that specific key factors are important for a pharmaceutical manufacturer to manage incoming customer orders efficiently and effectively to reduce possible out-of-stock situations amongst its end customers. However, the respondents also highlighted that there were a number of obstacles preventing them from implementing the key factors that are required to manage incoming customer orders more efficiently within the pharmaceutical manufacturer. Some of these obstacles include: the lack of pro- activeness; lack of accountability; and the lack of constant communication between the employees from the three main departments. Furthermore, incomplete hand-over information during shift changes amongst the employees of the Production and Packing department created unnecessary down-time. Also, the employees from the Warehouse and Distribution department were not informed timeously when changes to the production schedule were made. These obstacles will have a negative impact on the ultimate customer delivery dates and need to be addressed. The empirical results highlighted some recommendations to assist pharmaceutical manufacturing companies to more effectively and efficiently manage their incoming customer orders to reduce or eliminate any possible out-of-stock situations amongst its end customers. Some recommendations include: improved communication between the three main departments; to react immediately to out-of-stock products; and to ensure that internal and external customer service levels are adhered to at all times. The implementation of the recommendations based on the empirical findings of the study will assist the pharmaceutical manufacturing company to achieve excellence and to become a world-class supplier of generic pharmaceutical products. In this way, all incoming customer orders can be fulfilled on time

    Management, Technology and Learning for Individuals, Organisations and Society in Turbulent Environments

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    This book presents the collection of fifty papers which were presented in the Second International Conference on BUSINESS SUSTAINABILITY 2011 - Management, Technology and Learning for Individuals, Organisations and Society in Turbulent Environments , held in Póvoa de Varzim, Portugal, from 22ndto 24thof June, 2011.The main motive of the meeting was growing awareness of the importance of the sustainability issue. This importance had emerged from the growing uncertainty of the market behaviour that leads to the characterization of the market, i.e. environment, as turbulent. Actually, the characterization of the environment as uncertain and turbulent reflects the fact that the traditional technocratic and/or socio-technical approaches cannot effectively and efficiently lead with the present situation. In other words, the rise of the sustainability issue means the quest for new instruments to deal with uncertainty and/or turbulence. The sustainability issue has a complex nature and solutions are sought in a wide range of domains and instruments to achieve and manage it. The domains range from environmental sustainability (referring to natural environment) through organisational and business sustainability towards social sustainability. Concerning the instruments for sustainability, they range from traditional engineering and management methodologies towards “soft” instruments such as knowledge, learning, and creativity. The papers in this book address virtually whole sustainability problems space in a greater or lesser extent. However, although the uncertainty and/or turbulence, or in other words the dynamic properties, come from coupling of management, technology, learning, individuals, organisations and society, meaning that everything is at the same time effect and cause, we wanted to put the emphasis on business with the intention to address primarily companies and their businesses. Due to this reason, the main title of the book is “Business Sustainability 2.0” but with the approach of coupling Management, Technology and Learning for individuals, organisations and society in Turbulent Environments. Also, the notation“2.0” is to promote the publication as a step further from our previous publication – “Business Sustainability I” – as would be for a new version of software. Concerning the Second International Conference on BUSINESS SUSTAINABILITY, its particularity was that it had served primarily as a learning environment in which the papers published in this book were the ground for further individual and collective growth in understanding and perception of sustainability and capacity for building new instruments for business sustainability. In that respect, the methodology of the conference work was basically dialogical, meaning promoting dialog on the papers, but also including formal paper presentations. In this way, the conference presented a rich space for satisfying different authors’ and participants’ needs. Additionally, promoting the widest and global learning environment and participation, in accordance with the Conference's assumed mission to promote Proactive Generative Collaborative Learning, the Conference Organisation shares/puts open to the community the papers presented in this book, as well as the papers presented on the previous Conference(s). These papers can be accessed from the conference webpage (http://labve.dps.uminho.pt/bs11). In these terms, this book could also be understood as a complementary instrument to the Conference authors’ and participants’, but also to the wider readerships’ interested in the sustainability issues. The book brought together 107 authors from 11 countries, namely from Australia, Belgium, Brazil, Canada, France, Germany, Italy, Portugal, Serbia, Switzerland, and United States of America. The authors “ranged” from senior and renowned scientists to young researchers providing a rich and learning environment. At the end, the editors hope, and would like, that this book to be useful, meeting the expectation of the authors and wider readership and serving for enhancing the individual and collective learning, and to incentive further scientific development and creation of new papers. Also, the editors would use this opportunity to announce the intention to continue with new editions of the conference and subsequent editions of accompanying books on the subject of BUSINESS SUSTAINABILITY, the third of which is planned for year 2013.info:eu-repo/semantics/publishedVersio

    The single machine serial batch production scheduling with outsourcing allowed

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    Razmatramo nekoliko problema planiranja proizvodnje u serijama s dopuơtenom mogućnoơću ugovaranja proizvodnje s vanjskim proizvođačem (outsourcing). Postoji mogućnost da se svaki posao obavi na vlastitom stroju ili se ugovori s drugim poduzećem. Cilj je smanjiti ponderirani iznos cijene planirane proizvodnje i ukupne cijene outsourcinga. Razmatramo tri klasične objektivne funkcije programiranja. Prva je ukupno vrijeme izvrơenja, druga je maksimalno kaơnjenje, a treća je ponderirani broj kasnih poslova. Za svaki problem izvodima učinkovit dinamički algoritam programiranja koji minimalizira ukupni troơak.We consider several serial batch scheduling problems with outsourcing allowed. Each job can be either processed on the in-house machine or outsourced. The objective is to minimize the weighted sum of the scheduling cost and the total outsourcing cost. We discuss three classical scheduling objective functions. The first is the total completion time, the second is the maximum lateness, and the third is the weighted number of late jobs. For each problem, we derive an efficient dynamic programming algorithm that minimizes the total cost

    Energy-Efficient Flexible Flow Shop Scheduling With Due Date and Total Flow Time

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    One of the most significant optimization issues facing a manufacturing company is the flexible flow shop scheduling problem (FFSS). However, FFSS with uncertainty and energy-related elements has received little investigation. Additionally, in order to reduce overall waiting times and earliness/tardiness issues, the topic of flexible flow shop scheduling with shared due dates is researched. Using transmission line loadings and bus voltage magnitude variations, an unique severity function is formulated in this research. Optimize total energy consumption, total agreement index, and make span all at once. Many different meta-heuristics have been presented in the past to find near-optimal answers in an acceptable amount of computation time. To explore the potential for energy saving in shop floor management, a multi-level optimization technique for flexible flow shop scheduling and integrates power models for individual machines with cutting parameters optimisation into energy-efficient scheduling issues is proposed. However, it can be difficult and time-consuming to fine-tune algorithm-specific parameters for solving FFSP
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