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multi-objective optimization

در نشریات گروه صنایع
تکرار جستجوی کلیدواژه multi-objective optimization در نشریات گروه فنی و مهندسی
  • Ashish Trivedi *, Vibha Trivedi, Binoy Debnath, A. B. M. Bari
    The recent global efforts to control the spread of highly contagious COVID-19 pandemic have been successful, largely due to extensive vaccination campaigns. However, these campaigns have generated an enormous amount of infectious medical waste. This paper presents a weighted goal programming-based optimization model for managing medical waste generated from COVID-19 vaccination efforts. The model proposes an efficient system by integrating decisions of locating treatment centers and the routing of generated waste to these centers and eventually to disposal sites, with a focus on cost reduction, risk mitigation for the environment and the nearby population. The objectives include minimizing the setup and transportation costs, reducing risks to the population, limiting the number of installed units, and ensuring environmental sustainability of disposal sites. A set of randomly selected test instances is used to test the model's effectiveness. The results indicate that the compromised solution provides both cost benefits and reduced risk to the population. Specifically, the cost objective was compromised by only 5.98% and the risk objective by 1.54%, while the environmental sustainability objective was fully achieved.  This approach effectively supports strategic choices in recycling healthcare waste generated from COVID-19 immunization. The study is expected to aid municipal managers and decision-makers of healthcare facilities in managing vaccination related waste more efficiently.
    Keywords: Multi-Objective Optimization, Goal Programming, COVID-19, Vaccination, Medical Waste, Sustainability
  • Zeinab Kazemi, Mahdi Homayounfar *, Mehdi Fadaei, Mansour Soufi, Ali Salehzadeh

    Management of blood product consumption is a complex and important issue in health systems. Limited blood supply, corruption, special conditions for storage of blood products, and high costs due to losses and lack of blood in medical centers are among the factors affecting the problem. In this study, all three levels of donors, blood collection centers, and customers (hospitals) are considered for modeling the blood supply network in the form of a multi-objective model. Three objectives of the proposed model are: (a) minimizing total costs, (b) minimizing total delivery time of blood units, and (c) minimizing the maximum unmet demand of hospitals in each period. Next, the model used two multi-objective optimization algorithms namely NSGAII and MOPSO algorithms for solving 30 sample problems in different dimensions (small, medium, and large). After solving the sample problems, the efficiency of the two algorithms were compared with each other. According to the results, for the cost objective function and each of its components separately, it can be seen that the values resulted from the NSGA-II algorithm were less than the MOPSO . Finally, a real word data set from the Tehran blood center was used to evaluate the validity of the proposed model.

    Keywords: Multi-Objective Optimization, Blood, Supply Chain, Genetic Algorithm, NSGA II
  • سید محمد سجادیان*، رضا حسنوی، مرتضی عباسی

    طراحی بهترین ترکیب تامین کنندگان و مدل های بهینه سازی تیم سازی، همیشه یکی از تصمیم های مهم زنجیره تامین است. با توجه به چالش ها و تهدیدهای روزافزون زنجیره های تامین، بازطراحی شبکه تامین کنندگان بر اساس رویکردهای ترکیبی بر پایه ی مدل های ریاضی و در نظر گرفتن پشتیبان و قابلیت اطمینان ضروری می باشد. برای حل مشکل، این مقاله یک رویکرد سه مرحله ای برای تیم سازی و طراحی شبکه تامین کننده قابل اعتماد، با تمرکز بر یک مدل چندهدفه که تئوری مجموعه های فازی و تحلیل شبکه را ادغام می کند، توسعه می دهد و همچنین، به اهمیت نسبی روابط دقیق بین اعضاء با استفاده از منطق فازی)کارگاه تخصصی و استنتاج فازی(، تیم پشتیبان، قابلیت ها)مهارت، دانش(، ظرفیت، تخصیص سفارش و شبکه های همکاری قابل اعتماد می پردازد. در پایان، از شاخص های مرکزیت تحلیل شبکه برای پیشنهاد رهبر)های(تیم استفاده و برای اعتبارسنجی مدل پیشنهادی و حل مسائل در مقیاس کوچک از روش محدودیت اپسیلون تقویت شده استفاده می شود. این رویکرد، با مطالعه عددی داده های واقعی دوربین الکترواپتیکال برای طراحی و انتخاب شبکه ای از تامین کنندگان قابل اعتماد و تخصیص سفارش ارزیابی می شود. نتایج نشان می دهد که این رویکرد بر اساس تمامی مفروضات، شبکه تامین کننده قابل اعتماد و تیم بهینه را در دو مجموعه پشتیبان و اصلی انتخاب و رهبران تیم را با شاخص های مرکزیت تحلیل شبکه پیشنهاد می کند. توسعه و حل مدل با الگوریتم های فراابتکاری برای حل مسائل مقیاس بزرگ پیشنهاد می شود.

    کلید واژگان: تیم سازی و طراحی شبکه تامین کننده، انتخاب تامین کننده قابل اعتماد و تخصیص سفارش، تجزیه و تحلیل شبکه، استنتاج فازی، تجزیه و تحلیل روابط، بهینه سازی چندهدفه
    S.M. Sadjadiyan *, R. Hosnavi, M. Abbasi

    Faced with increasing threats and challenges of supply chains, it is necessary to redesign the supplier network based on hybrid approaches based on mathematical models and reliability. To solve the problem, this paper presents a new approach. Team formation, selection, design, and composition are still critical success or failure factors in any business within a company and organization. Criteria, parameters, various qualitative and quantitative methods, approaches, and techniques have been presented by several studies in TF so far. This study developed a hybrid approach to team formation (TF) and reliable supplier network design, focusing on a multi-objective model integrating fuzzy-set theory and social network analysis. Furthermore, this study addressed the relative importance value of precise relationships between members using fuzzy logic (expert workshop and fuzzy inference), backup team, capabilities (skills, expertise, or knowledge), capacity, and order allocation. It also carefully considers the relationships between team members using expert workshops and fuzzy inferences. Also, social network analysis metrics are used to suggest team leader(s). We used the augmented epsilon constraint (AUGMECON2) method to validate the model and solve small-scale problems with exact solutions. The model aimed to form a reliable team and supplier network with a maximum level of reliability, maximize the network weight of collaboration, and maximize the knowledge level of the main members( suppliers), simultaneously. The approach was evaluated through a numerical study of the actual data of the electro-optical camera for team formation, design and selection of a network of reliable suppliers, and order allocation. The results showed that the approach carefully selects the optimal supplier network and team based on all assumptions and suggests team leaders with social network analysis. One of the advantages of our model is simultaneously considering supplier network, reliability, FIS, and SNA in team formation. The use of uncertain data and combined methods and MADM for preselection can also be e ective. The strategy of the optimal number of modules and product subsystems can also be included in the model. In future studies, other variables and parameters such as time, design phases, and the total cost can be considered. Also, because the problem is NP-hard; the use of meta-heuristic algorithms is suggested. Modeling a multi-product multi-period supply chain problem is suggested.

    Keywords: Team Formation, Design Supplier Networking, Reliable Supplier Selection, Order Allocation, Socialnetwork Analysis, Fuzzy Inference, Relationship Analysis, Multi-Objective Optimization
  • زهرا سعیدی مبارکه، حسین عموزادخلیلی*
    این تحقیق به معرفی یک مدل بهینه سازی چندهدفه غیرخطی می پردازد که برای بهینه سازی هم زمان سود و رضایت مشتری در سیستم های تولیدی طراحی شده است. مساله مورد بررسی شامل بهینه سازی در شرایط پیچیده و نامطمئن تولید است که با محدودیت های منابع و زمان مواجه است. مدل پیشنهادی با به کارگیری توابع هدف غیرخطی و تحلیل دقیق شرایط عملیاتی، راه حل های بهینه ای را برای مدیران ارائه می دهد. این منطق فازی با الگوریتم های یادگیری ماشین نظیر شبکه های عصبی و یادگیری تقویتی ترکیب شده است تا مدلی هوشمند و انعطاف پذیر ایجاد شود که به طور موثری با تغییرات ناگهانی در محیط های پویا سازگار می شود. این مدل از ترکیب الگوریتم های ژنتیک مرتب سازی غیر مسلط چهارم (NSGA-IV) و شبکه انتخاب متغیر (VSN) در یک چارچوب ترکیبی بهره می برد و رویکردی پیشرفته و چندوجهی برای حل مسائل پیچیده بهینه سازی چندهدفه ارائه می کند. نتایج پارتو-بهینه حاصل از این مدل نشان دهنده عملکرد کارآمد و بهینه آن است. مدل پیشنهادی می تواند به عنوان منبعی عملی و راهبردی برای مدیران و تصمیم گیران در بهینه سازی تولید و ارتقاء رضایت مشتری در شرایط نامطمئن و پویا مورد استفاده قرار گیرد.
    کلید واژگان: بهینه سازی چندهدفه، منطق فازی، یادگیری ماشین، الگوریتم فرا ابتکاری ترکیبی چند هدفه
    Zahra Saeidi Mobarakeh, Hossein Amoozadkhalili *
    This research introduces a nonlinear multi-objective optimization model that is designed to simultaneously optimize profit and customer satisfaction in production systems. The investigated problem includes optimization in complex and uncertain conditions of production, which is faced with resource and time limitations. The proposed model provides optimal solutions for managers by using non-linear objective functions and detailed analysis of operating conditions. This fuzzy logic is combined with machine learning algorithms such as neural networks and reinforcement learning to create an intelligent and flexible model that effectively adapts to sudden changes in dynamic environments. This model uses the combination of non-dominant fourth sorting genetic algorithms (NSGA-IV) and variable selection network (VSN) in a hybrid framework and provides an advanced and multi-faceted approach to solving complex multi-objective optimization problems. Pareto-optimal results obtained from this model indicate its efficient and optimal performance. The proposed model can be used as a practical and strategic source for managers and decision makers in optimizing production and improving customer satisfaction in uncertain and dynamic conditions.
    Keywords: Multi-Objective Optimization, Fuzzy Logic, Machine Learning, Hybrid Multi-Objective Meta-Heuristic Algorithm
  • فرشته سرآبادانی، رامین بازوکار، فاطمه رشیدیان*
    امروزه توسعه پایدار به عنوان جایگزین توسعه صنعتی با پیامدهای زیست محیطی و کمبود منابع کره زمین، به دغدغه اصلی در جوامع تبدیل شده است. مدیران صنایع به دنبال روش هایی هستند که ضمن حمایت از محیط زیست، عملکرد سازمان خود را افزایش دهند. در این راستا توجه به زنجیره تامین سبز، موردتوجه زیادی قرارگرفته است. یکی از راه حل های این مساله که اخیرا توجه صنایع و محققان را به خود جلب کرده، انتخاب تامین کننده سبز می باشد. یعنی واحدهای خرید در شرکت ها باید به معیارهای سبز بودن در فرآیند خریدشان از تامین کننده ها در سراسر زنجیره تامین، توجه کنند. مفهوم تامین کننده سبز، عبارت است از تهیه موادی که منابع و انرژی کمتر مصرف نموده و غیر سمی بوده و موجب نابودی محیط زیست نمی شود. هدف مقاله حاضر، توسعه یک مدل دوهدفه مبتنی بر معیارهای سنتی و سبز انتخاب تامین کننده و تلفیق همزمان روش AHP فازی، بهینه سازی چندهدفه در کنار استفاده از مفهوم تخفیف افزایشی می باشد. در این پژوهش یک مدل یکپارچه که تصمیمات مرتبط با قیمت و معیارهای سنتی با معیارهای سبز برای انتخاب تامین کننده سبز را با یکدیگر ترکیب می نماید، ارائه شده است. درنهایت عملکرد مدل با استفاده از یک مثال واقعی در نرم افزار لینگو و به روش آل پی متریک موردبررسی و تجزیه وتحلیل قرارگرفته است. پس از حل مدل دو هدفه مذکور مقدار تابع هدف اول برابر 3/547628 و مقدار تابع هدف دوم برابر 1060513 می باشد.
    کلید واژگان: بهینه سازی چندهدفه، زنجیره تامین سبز، انتخاب تامین کننده سبز، برنامه ریزی ریاضی
    Fereshte Sarabadani, Ramin Bazoukar, Fateme Rashidian *
    Today, sustainable development has been proposed as an alternative to industrial development, and the environmental consequences and lack of resources on the planet have become the main concern of societies. Industry managers, especially in advanced countries, are looking for ways to increase the performance of their organization while protecting the environment. In this regard, paying attention to the green supply chain has received a lot of attention. One of the solutions to this problem, which has recently attracted the attention of industries and researchers, is choosing a green supplier. That is, purchasing units in companies should pay attention to green criteria in their purchasing process from suppliers throughout the supply chain. The concept of green supplier is to provide materials that consume less resources and energy and are non-toxic and do not destroy the environment. The aim of this paper is to develop a bi-objective model based on traditional and green supplier selection criteria and the simultaneous integration of the fuzzy AHP method, multi-objective optimization along with the use of the incremental discount concept. In this research, an integrated model that combines price-related decisions and traditional criteria with green criteria for selecting a green supplier has been presented. Finally, the performance of the model has been investigated and analyzed using a real example in the Lingo software and by the LP metric method. After solving the mentioned bi-objective model, the value of the first objective function is equal to 3.547628 and the value of the second objective function is equal to 1060513.
    Keywords: Multi-Objective Optimization, Green Supply Chain, Choosing A Green Supplier, Mathematical Programming
  • Ali Salmasnia, Elahe Heydarnezhad, Hadi Mokhtari*

    One of the important problems in managing construction projects is selecting the best alternative for activities' execution to minimize the project's total cost and time. However, uncertain factors often have negative effects on activity duration and cost. Therefore, it is crucial to develop robust approaches for construction project scheduling to minimize sensitivity to disruptive noise factors. Additionally, existing methods in the literature rarely focus on environmentally conscious construction management. Achieving these goals requires incorporating the project scheduling problem with multiple objectives. This study proposes a robust optimization approach to determine the optimal construction operations in a project scheduling problem, considering time, cost, and environmental impacts (TCE) as objectives. An analytical algorithm based on Benders decomposition is suggested to address the robust problem, taking into account the inherent uncertainty in activity time and cost. To evaluate the performance of the proposed solution approach, a computational study is conducted using real construction project data. The case study is based on the wall of the east coast of Amirabad port in Iran. The results obtained using the suggested solution approach are compared to those of the CPLEX solver, demonstrating the appropriate performance of the proposed approach in optimizing the time, cost, and environment trade-off problem.

    Keywords: Time-Cost-Environment Trade off Problem, Project Scheduling, Multi-Objective Optimization, Robust Optimization, Benders Decomposition
  • Fatemeh Kangi, Seyed Hamidreza Pasandideh *, Esmaeil Mehdizadeh, Hamed Soleimani

    In recent years, expanding the social responsibility concept, increased environmental considerations, economic incentives, and governmental pressure on manufacturers for waste management have caused organizations to focus on developing Closed-Loop Supply Chains (CLSC) and Reverse Logistics (RL) processes. Adopting these approaches will enable organizations to meet economic, social, and environmental goals simultaneously and consider the manufacturing cycle from supply and production to product reuse. Hence, this study deals with an optimization model within the framework of a multi-echelon, multi-product, and multi-period CLSC with hybrid facilities where cross-docking strategy and vehicle routing with soft time windows have been included. In the problem defined as a MILP model, decisions are made simultaneously at three strategic, tactical, and operational levels. Furthermore, to tackle the NP-hard problem and achieve near-to-optimal results in a reasonable time, two meta-heuristic algorithms, NRGA and MOPSO, are developed, and the algorithms' parameters are tuned using the Taguchi method. Finally, the computational results are examined using performance measures and statistical analysis. A sensitivity analysis is performed regarding the impacts of demand and the rate of returned products on the values of the objective functions.

    Keywords: Closed-Loop Supply Chain, Hybrid Facilities, Cross-Docking Delivery Strategy, Vehicle Routing, Time Windows, Multi-Objective Optimization, De Novo Programming
  • Zahra Yadegari, Seyyed Mohammad Hadji Molana *, Ali Husseinzadeh Kashan, Seyed Esmaeil Najafi
    A novel mixed integer non-linear mathematical model is presented in this paper for the two-echelon allocation-routing problem by applying the conditions of the route and transportation fleet under uncertainty. The cost of allocating drivers to non-homogeneous vehicles is calculated in this model based on the type of the vehicle, the lifecycle of the car, the experience of the driver, and different degrees of hardness that are defined for various routes. The cost of passing the route is defined based on an initial fixed cost and the degree of hardness of the route. Also, the reliability of the routes in each section is defined as an objective in the second echelon of the model aimed at enhancing the reliability rate. Two metaheuristic algorithms, NSGAII and MOPSO, are utilized to solve the model. Then, their performance rates in problems with different sizes are statistically evaluated and compared by different indices, following the adjustment of their parameters by Taguchi's method, through which results indicated the high efficiency of the model. A sensitivity analysis is ultimately performed on the results obtained from the solution, and some suggestions are made for the development of the model.
    Keywords: Two-Echelon Allocation-Routing Model, Reliability, Multi-Objective Optimization, Metaheuristic Algorithms
  • الهام نجاتی، مهدی یوسفی نژاد عطاری*، عسگر حاجی بدلی
    هدف

    یکی از حیاتی ترین زیر مجموعه های سیستم مراقبت های بهداشتی پیوند عضو می باشد و از آن جاکه مراکز پیوند عضو به صورت مستقیم با عمل های جراحی و درنتیجه، زندگی انسان ها سروکار دارند، اهمیت این موضوع مورد توجه بیشتری قرار گرفته است. یکی از عمده ترین تفاوت های زنجیره تامین پیوند عضو با سایر زنجیره های تامین احتمال فساد محصولات مربوطه می باشد. لذا زمان و هم چنین بحث مکان یابی مراکز پیوند عضو از اهمیت ویژه ای برخوردار است. از طرفی، با توجه به رشد سریع تقاضا برای پیوند عضو و کمبود منابع، زمان انتظار بیمار برای تکمیل پروسه پیوند نقش حیاتی را در سیستم پیوند اعضا ایفا می کند.

    روش شناسی پژوهش:

     این مطالعه یک مدل ریاضی دوهدفه استوار برای مساله مکان یابی تخصیص مراکز پیوند عضو تحت شرایط عدم قطعیت ارایه می دهد که هزینه های کل سیستم پیوند عضو و هم چنین میانگین زمان انتظار بیمار برای انجام پیوند عضو را که از یک سیستم صف G/G/m تبعیت می کند، کمینه می سازد.

    یافته ها

    برای حل این مدل الگوریتم ژنتیک رتبه بندی نامغلوب (NSGA-II) به کار گرفته شده است. درنهایت، قابلیت اجرای این مدل و کارایی الگوریتم مذکور نسبت به شاخص های تعریف شده از طریق آزمایش های عددی نشان داده شده است.

    اصالت/ارزش افزوده علمی: 

    از آن جاکه هر عضو زمان مشخصی را می تواند خارج از بدن سپری کند و احتمال فساد یا کاهش کیفیت پیوند وجود دارد، زمان بین خروج عضو از بدن و تکمیل عمل پیوند نقشی اساسی در سیستم پیوند عضو ایفا می کند.

    کلید واژگان: بهینه سازی چندهدفه، الگوریتم NSGA-II، پیوند عضو، تئوری صف، مدیریت زنجیره تامین
    Elham Nejati, Mahdi Yousefi Nejad Attari *, Asgar Hajibadali
    Purpose

    One of the most vital subcategories of the health care system is organ transplantation, and since organ transplant centers deal directly with surgical operations and, as a result, human lives, the importance of this issue has received more attention. One of the major differences between the organ transplant supply chain and other supply chains is the possibility of corruption of related products. Therefore, the time and also the location of organ transplant centers are of special importance. On the other hand, due to the rapid growth of the demand for organ transplantation and the lack of resources, the patient's waiting time to complete the transplantation process plays a vital role in the organ transplantation system.

    Methodology

    This study presents a robust bi-objective mathematical model for the location problem of allocating organ transplant centers under uncertainty, which includes the total costs of the organ transplant system as well as the average patient waiting time for organ transplantation, which follows a G/G/m queuing system.

    Findings

    To solve this model, the Non-Dominated Sorting Genetic Algorithm II (NSGA-II) has been used. Finally, the applicability of this model and the efficiency of the mentioned algorithm compared to the defined indicators have been shown through numerical experiments.

    Originality/Value:

     Since each organ can spend a certain amount of time outside the body and there is a possibility of corruption or a decrease in the quality of the transplant, the time between the organ leaving the body and the completion of the transplant operation plays an essential role in the transplant system.

    Keywords: Multi objective Optimization, NSGA-II algorithm, organ transplantation, Queuing Theory, Supply chain management
  • اعظم مدرس، وحیده بافندگان امروزی، زهرا مهمی*، آزاده مدرس
    طراحی کار آمد زنجیره تامین باعث بهبود عملکرد در سازمان ها می شود. این موضوع در زنجیره تامین محصولات کشاورزی کمتر مورد توجه قرار گرفته است. در این مطالعه تلاش می شود با رویکردی یکپارچه به بررسی برنامه ریزی برای تامین، تولید و توزیع پرداخته شود.  در این پژوهش یک مدل برنامه ریزی عدد صحیح چند هدفه که به دنبال حداقل کردن هزینه ها،  آثار زیست محیطی و حداکثر کردن اهمیت تامین کنندگان می باشد، ارایه شده است. در این پژوهش از ترکیبی از روش های تصمیم گیری چند معیاره برای اولویت بندی تامین کنندگان استفاده شد. پس از آن وزن های به دست آمده تحت ورودی های مدل چند هدفه در نظر گرفته شدند. مدل پیشنهادی با در نظر گرفتن ترکیبی از معیارهای کیفی و کمی و با توازن برقرار کردن بین معیارها می تواند ترکیبی از بهترین تامین کنندگان را پیدا کند. مقایسه جواب های حاصل از مدل ارایه شده با میزان واقعی متغیرها در بازه زمانی مورد مطالعه تفاوت آشکار در هزینه ها را روشن ساخت و نتایج حاکی از آن است که مدل ارایه شده   می تواند هزینه ها را به میزان قابل توجهی کاهش دهد. با انجام تحلیل حساسیت بر روی یکی از پارامترهای کلیدی مدل (تقاضا)، اثر این پارامتر بر توابع هدف بررسی شد و نتایج نشان دادند در فاصله تغییرات 10 درصدی در میزان تقاضا تفاوت قابل ملاحظه ای در توابع هدف مشاهده نمی شود در حالی که  اگر تغییرات تقاضا در محدوده 20 درصدی تغییر کند تفاوت آشکاری در توابع هدف پدید می آید. بنابراین می توان گفت جواب های حاصل از حل مدل و در زمان مناسب حاکی از کارایی و صحت مدل می باشد و مبین قابلیت مدل مذکور برای پاسخگویی به شرایط واقعی است. جهت اعتبار سنجی مدل ارایه شده جواب های حاصل با میزان واقعی متغیرها در بازه زمانی مورد مطالعه مقایسه گردیده که نتایج حاکی از کاهش هزینه در مدل ارایه شده می باشد. بنابراین می توان گفت جواب های حاصل از حل مدل و در زمان مناسب حاکی از کارایی و صحت مدل می باشد و مبین قابلیت مدل مذکور برای پاسخگویی به شرایط واقعی است.
    کلید واژگان: زنجیره تامین، بهینه سازی چند هدفه، برنامه ریزی خطی متریک، لجستیک یکپارچه
    Azam Modares, Vahideh Bafandegan Emroozi, Zahra Mohemmi *, Azade Modares
    Efficient supply chain design improves performance in organizations. This issue has been given less attention in the supply chain of agricultural products. This study uses an integrated approach to planning for supply, production, and distribution. This research presents a  multi-objective integer programming model that seeks to minimize costs, environmental effects and maximize suppliers' importance. This research used a combination of             multi-criteria decision-making methods to prioritize suppliers. After that, the obtained weights were considered under the inputs of the multi-objective model. The proposed model can find a combination of the best suppliers by considering a variety of qualitative and quantitative criteria and balancing the criteria. Comparing the answers obtained from the presented model with the actual amount of variables in the studied period clarified the apparent difference in costs. The results indicate that the proposed model can reduce costs significantly. The effect of this parameter on the objective functions was investigated by performing a sensitivity analysis on one of the critical parameters of the model (demand). The results showed that there is no significant difference in the objective functions within the interval of 10% changes in the amount of demand. In comparison, if the demand changes within 20%, a noticeable difference in the objective functions appears. Therefore, it can be said that the answers obtained from solving the model at the right time indicate the model's efficiency and accuracy and show the model's ability to respond to actual condition.
    Keywords: Supply Chain, Multi-Objective Optimization, L-P metric, Integrated Logistics
  • رضا بیرانوند، عبدالله آقایی*

    جوامع کنونی خود را ملزم می دانند برای واکنش موثر و کاهش اثرات مخرب فجایع به وجود آمده، برنامه ریزی های لازم را انجام دهند. در این تحقیق، یک مدل برنامه ریزی ریاضی تحت عدم قطعیت برای امدادرسانی و واکنش به بحران زلزله توسعه داده شده است. در مدل ارایه شده برای افزایش قابلیت اطمینان، احتمال خرابی تسهیلات باتوجه به شدت زلزله درنظر گرفته می شود. مراکز توزیع، دو نوع درنظر گرفته می شوند، نوع اول مراکز توزیع محلی، که از مراکز عمومی استفاده می شود و نزدیک به نقاط حادثه هستند، این نوع مراکز از این جهت که از مراکز عمومی استفاده می کنند، احتمال خرابی دارند. نوع دیگر، مراکز توزیع قابل اطمینان هستند که درخارج از منطقه حادثه، احداث می شوند و به دلیل صرف هزینه بیشتر برای ساخت آن ها احتمال خرابی بسیار کمی دارند. در مدل جدید ارایه شده سعی شده است علاوه بر درنظر گرفتن قابلیت های اطمینان، در بحث حمل ونقل نیز با درنظر گرفتن حالت چند سفره در وسایل نقلیه، مدل کامل تری برای برنامه ریزی ارایه گردد. عدم قطعیت با استفاده از رویکرد احتمال مبتنی بر سناریو مدل سازی و یک مطالعه موردی از شهر تهران برای نشان دادن عملکرد مدل پیشنهادی ارایه می شود. نتایج حاصل شده از مدل پیشنهادی نشان می دهد، امدادرسانی موثر و کاراتری از نظر زمان و هزینه انجام می پذیرد، ازاین رو می تواند به مدیران بحران در واکنش به بحران به وجود آمده در جهت تامین بودجه موردنیاز و برنامه ریزی لجستیکی مناسب کمک نماید.

    کلید واژگان: زنجیره تامین بشردوستانه، بحران، قابلیت اطمینان، شبکه توزیع امداد، بهینه سازی چندهدفه
    R. Beiranvand, A. Aghaei

    Current societies are obliged to make the necessary plans for effective response and reducing the destructive effects of disasters. In this research, a mathematical planning model under uncertainty has been developed for earthquake relief and response. In the presented model to increase the reliability, the possibility of facility failure is considered according to the intensity of the earthquake. Distribution centers are considered to be of two types, the first type is local distribution centers, which use public centers and are close to the accident points, these types of centers are prone to failure because they use public centers. Another type is the reliable distribution centers that are built outside the accident area and have a very low probability of failure due to spending more money to build them. In the new model presented, in addition to considering the reliability capabilities, it has been tried to provide a more complete model for planning in the transportation issue by considering the multi-trips mode in the vehicles. Uncertainty is presented using the probability approach based on the modeling scenario and a case study from the city of Tehran to show the performance of the proposed model. The results obtained from the proposed model show that effective and efficient aid delivery is done in terms of time and cost, therefore it can help crisis managers in response to the crisis in order to provide the required budget and appropriate logistics planning.

    Keywords: Humanitarian Supply Chain, Crisis, Reliability, Relief Distribution Network, Multi-Objective Optimization
  • Ataollah Taghaddosi, Mohammad Ali Afshar Kazemi *, Arash Sharifi, Mohammad Ali Keramati, Amir Daneshvar
    Considering the extensive application of dynamic multi-objective optimization problems (DMOPs) and the significance of the quality of solutions, developing optimization methods to find the finest solutions takes a privileged position, attracting considerable interest. Most optimization methods involve multiple conflicting objectives that change over time. The present article develops an electromagnetic field optimization (EFO) using decomposition, crowding distance, and the quantum behavior of particles techniques to solve multi-objective problems. In the proposed algorithm, the position of new particles is determined between the neighbors within the MOEA/D by drawing inspiration from the quantum delta potential well model, the nonlinear trajectory of quantum-behaved particles, and the interactions of electromagnetic particles introduced from positive and negative fields, which can offer superior exploration and exploitation. To develop the proposed algorithm for solving dynamic problems, the mean difference between particles' center of mass in the two latest changes to predict the extent of change is applied along with polynomial mutation and random reproduction. A total of 9 benchmarks from the set of DF functions and two metrics, i.e., MIGD and MHV, are used to assess the performance of the proposed algorithm. The results from 20 independent runs of the proposed algorithm on each benchmark function are compared with the results from other algorithms. The Wilcoxon Rank-Sum non-parametric statistical test is applied at the significance level of 5% to compare the mean results. The experimental results indicated that the proposed algorithm gains a significant superiority in metrics MIGA and MHV in most experiments. The simultaneously great results of these two metrics indicate a superior distribution and approximation of the Pareto front.
    Keywords: Dynamic, Multi-Objective Optimization, Electromagnetic field optimization (EFO), quantum mechanics
  • Mariam Ameli, Shima Haghighatpanah, Hamed Davari Ardakani *, Shiva S. Ghasemi
    The need for effective use of assets has become more important in the design of supply chain networks in today’s competitive environment. Sale and leaseback (SLB) agreements are one of the appropriate tools to achieve this important goal. The proper use of these agreements increases the liquidity of assets, and provides financial resources required for other activities. However, the consideration of SLB possibility in a Closed-Loop Supply Chain (CLSC) that aims to minimize 〖CO〗_2 emissions as well as maximizing profit has never studied before. Therefore, this paper proposes a bi-objective two-stage stochastic program for designing a CLSC network considering SLB agreements. The objective functions are: to maximize profit after tax and to minimize 〖CO〗_2 emissions of the supply chain. To assess the performance of the proposed model, 30 different-sized test problems are generated and solved by both LP-metric and max-min methods. Finally, sensitivity analysis is performed to assess the impact of SLB related parameters (the safety stock coefficient, the fair value of the leased asset, the interest rate implicit in the lease, and the lessee's incremental borrowing rate) on the objectives. The results show significant superiority of the proposed model over which do not consider SLB possibility. Outcomes also indicates that Lp-metric method provides better solutions for the problem. Finally, some managerial insights are suggested.
    Keywords: Closed-loop supply chain network design (CLSC), Scenario-based stochastic optimization, Sale, leaseback (SLB), 〖CO〗, 2 emissions, Multi-objective optimization
  • نجمه صیادی شهرکی، علی محمدی*

    تقویت کننده کم نویز LNA اولین عنصر بحرانی و مهم در طراحی سیستم های VLSI آنالوگ و تکنولوژی ارتباط بی سیم است. جهت برقراری یک مصالحه مناسب بین اهداف طراحی متناقض مدار LNA و ارتقاء شاخص های بهینگی و کارایی آن، در این مقاله از ابزار طراحی به کمک کامپیوتر (CAD) مبتنی بر بهره گیری از تکنیک های محاسبات نرم نظیر روش های بهینه سازی هوشمند فرا ابتکاری بهره گرفته شده است. بدین منظور سایزبندی هوشمند عناصر مداری و طراحی خودکار مدار توسط نسخه چندهدفه جدید و موثر الگوریتم بهینه سازی سیستم صفحات شیب دار بهبودیافته (MOMIPO) اجرا شده است. نتایج خروجی در مقایسه با سایر پژوهش ها نشانگر دستیابی مطلوب به شاخصه ها و قیود طراحی در کنار ارایه مجموعه جواب های متنوع در قالب جبهه پرتو می باشد. اجرای الگوریتم بهینه ساز در محیط MATLAB و شبیه سازی های مداری در نرم افزار HSPICE انجام شده است.

    کلید واژگان: بهینه سازی چندهدفه، روش فرا ابتکاری، LNA، CAD، MOMIPO
    Najmeh Shahraki, Ali Mohammadi *

    Low Noise Amplifier (LNA) is the first critical and important element in the designing of analog VLSI systems and wireless communications technology. In this paper, in order to establish an appropriate trade-off between the contradictory design objectives of an LNA circuit and the improvement of its efficiency and optimality indexes, a Computer-Aided Design (CAD) tool has been used based on the use of soft computing techniques including meta-heuristic intelligent optimization methods. For this purpose, the intelligent sizing of circuit elements and the auto-circuit design have been implemented by a new and effective Multi-Objective version of the Modified Inclined Planes System Optimization (MOMIPO) algorithm. Output results, compared with other studies, indicate a desirable achievement of design characteristics and constraints along with a variety of responses in the form of a Pareto Front. The execution of optimizer algorithm in the MATLAB environment and circuit simulations has been performed using the HSPICE software.

    Keywords: Multi-objective optimization, metha-heuristic method, LNA, CAD, MOMIPO
  • الهام ظهیری، عقیله حیدری، حمیدرضا یوسف زاده*

    وجو‏د مجموعه جواب های بهینه پارتو حاصل از حل مسایل بهینه سازی چندهدفه، هرچند از یک سو انعطاف پذیری در انتخاب یک جواب بهینه را با توجه به شرایط حاکم بر یک سیستم افزایش می دهد ولی از سوی دیگر، با توجه به وجود سلایق و دیدگاه های مختلف در یک سیستم، انتخاب مطلوب ترین جواب مرز پارتو، می تواند به عنوان یک چالش جدی مطرح شود. در این راستا، در این مقاله، در گام نخست، با تعریف مفهوم درجه نزدیکی گوسی و ارایه یک رویکرد تجزیه مبتنی بر آن، به تولید مرز پارتو می پردازیم که نتایج عددی نشان می دهد این مرز در مقایسه با مرزهای حاصل از رویکردهای تجزیه دیگر از کیفیت بالاتری برخوردار است. در گام دوم، با توجه به عدم وجود یک معیار ارزیابی که به بررسی کیفیت یک مرز ‏از زوایای مختلف بپردازد‏، یک معیار ارزیابی جدید برای مقایسه مرزهای مختلف ارایه می کنیم که با در نظر کرفتن هم زمان دو عامل میزان تسلط و نزدیکی به جواب بهینه به بررسی کیفیت جواب ها در یک مرز پارتو می پردازد. نتایج بدست آمده از شبیه سازی گام های پیشنهادی بر روی توابع آزمون استاندارد موجود، کارآیی و موثر بودن هر یک از گام های مسیله پیشنهادی را تصدیق می نمایند.

    کلید واژگان: : بهینه سازی چندهدفه (MOO)، چیرگی، چیرگی فازی، تقریب سازی، مرز پارتو
    Elham Zahiri, Aghile Heidari, Ham, Id Reza Yoosefzade *

    The Pareto set of optimal solutions resulting from solving multi-objective optimization problems, although on the one hand increases the flexibility in choosing an optimal solution according to the conditions of a system, but on the other hand, due to different tastes and perspectives in a The system, choosing the most desirable Pareto front answer, can be a serious challenge. In this regard, in this article, in the first step, by defining the concept of Gaussian degree of proximity and presenting a decomposition approach based on it, we produce the Pareto front, which numerical results show that this front in comparison with fronts obtained from other quality decomposition approaches. Has a higher. In the second step, due to the lack of an evaluation criterion that examines the quality of a front from different angles, we present a new evaluation criterion for comparing different fronts, which by considering both factors of mastery and proximity to the optimal answer. Examines the quality of the answers on a Pareto front. The results obtained from the simulation of the proposed steps on the existing standard test functions confirm the efficiency and effectiveness of each of the steps of the proposed problem.

    Keywords: ‎ Multi-objective optimization, Domination. Fuzzy domination, approximation, Pareto Frontier
  • Somaye Ghandi *, Nafiseh Ghazavi
    The Assembly Line Balancing (ALB) problem is one of the subproblems of the Assembly Planning(AP) problem and is defined as the process of partitioning the assembly operations into a set of tasks and assigning them to assembly workstations such that all workstations approximately have equal times. The most basic model in ALB is the Simple Assembly Line Balancing Problem for type 2 (SALBP2). The mentioned problem is an NP-hard problem and thus many researchers in the field tried to find an effective and efficient solution for it. However, the fitness landscape of this problem has not been yet studied despite the existence of numerous works on solving it. In this article, different statistical correlation and distribution measures are used and calculated in order to analyze the fitness landscape of the SALBP2 problem for 44 test problems. The results reveal that the problem's landscape is approximately uniform based on the distribution of the locally optimal assembly sequences. Therefore, for obtaining an effective and efficient solution to SALBP2 a suitable Hybrid Iterated Local Search (HILS) is designated and used to solve a number of SALBP2 problems. Comparison results with the other approaches in the SALBP2 literature represent that the HILS produces the optimal or best known solutions on most problem instances, and it performs better than other algorithms.
    Keywords: Assembly Line Balancing (ALB), Hybrid Iterated Local Search (HILS), Landscape Analysis, Multi-objective optimization, Simple Assembly Line Balancing Problem for Type 2 (SALBP2)
  • Sajad Amirian, Maghsoud Amiri *, Mohammad Taghi Taghavifard
    The competitive environment of the present age has focused the attention of organizations on meeting the requirements of quality and socially responsible, because organizations that adhere to the quality management framework achieve a higher level of customer satisfaction. In addition, the shorter product life due to the development of technology and changing customer needs reveals the need to pay attention to the concepts of sustainability and reliability in the design of the supply chain network. In this paper, the convergence of sustainability and reliability in supply chains is considered and a model of economic, responsible, and reliable supply chain is comprehensively and efficiently modeled. For this purpose, a nonlinear mixed-integer programming model for the supply chain network design problem is considered as three-objective, multi-product, multi-level, multi-source, multi-capacity, and multi-stage. In this study, the normalized normal constraint (NNC) method is used to solve the proposed multi-objective optimization problem and find Pareto optimal solutions. In addition, numerical examples with random data in different dimensions have been considered to measure the accuracy and overall performance of the proposed model and by changing the various parameters of the model, the sensitivity analysis of target functions has been performed to analyze the model behavior.
    Keywords: Sustainability, Reliability, Multi-Objective Optimization, NNC method, closed loop supply chain network
  • Majid Alimohammadi Ardekani *
    In recent years, supply chains have become an attractive topic for managers and industrialists, and the life and death of organizations and businesses somehow depend on the activity of intertwined chains. On the other hand, in today's highly competitive environment, the high speed of change and evolution has increased the uncertainty and ambiguity of decisions, which makes it difficult to predict future conditions in supply chains. Therefore, reliable planning should be done in uncertain and ambiguous conditions for better and more accurate planning. One of the new and reliable approaches is the robust programming approach. In this study, transferring petroleum products from supply points to consumption areas is examined through a supply chain. Due to the uncertainty in the product demand, a mathematical model is used with two objectives including the reduction of shipping costs and the reduction of the number of loads. Due to the high volume of calculations and the problem data as well as the lack of ability to use exact solution methods, especially on a large scale, PSO and MOGA-II meta-heuristic algorithms are used to solve the proposed model. The results show that the model has the required efficiency in large dimensions and the proposed solution methods provide appropriate answers.
    Keywords: Oil Supply Chain, Robust optimization, Multi-objective optimization, Meta-heuristic algorithm
  • Vahid Razmjooei *, Iraj Mahdavi, Selma Gutmen
    A Cellular Manufacturing System (CMS) is a suitable system for the economic manufacture of part families. Scheduling the manufacturing cells plays an effective role in successful implementation of the manufacturing system. Due to the fact that in the CMS, bottleneck machine and human resources are two important factors, which so far have not been studied simultaneously in a mathematical model, there should be a model to consider them. Therefore, this research develops a bi-objective model for CMS in a three-dimensional space of machine-part and human resources. The main objective is to minimize the maximum completion time of all tasks in the system and reduce the number of intercellular translocation based on bottleneck machines’ motion and human resources. Due to the NP-hardness of the studied problem, applying the conventional solution methods is very time-consuming, and is impossible in large dimensions. Therefore, the use of metaheuristic methods will be useful. The accuracy of the proposed model is investigated using LINGO by solving a small example. Then, to solve the problem in larger dimensions, a hybrid Multi-Objective Tabu Search-Genetic Algorithm (MO-TS-GA) is designed and numerical results are reported for several examples.
    Keywords: Cellular Manufacturing, scheduling, Multi-Objective Optimization, Human Resource Allocation
  • Hamed Davari Ardakani *, Ali Dehghani

    In this paper, a multi-objective mixed-integer programming model is developed to cope with the multi-mode resource-constrained project selection and scheduling problem, aiming to minimize the makespan, maximize the net present value of project cash flows, and minimize the fluctuation of renewable resource consumption between consecutive time periods. Moreover, activities are considered to be subject to generalized finish-to-start precedence relations, and time-varying resource usage between consecutive time periods. To assess the performance of the proposed model, 30 different-sized numerical examples are solved using goal programming, epsilon constraint, and augmented epsilon constraint methods. Afterward, Tukey test is used to statistically compare the solution methods. Moreover, VIKOR method is used to make an overall assessment of the solution methods. Statistical comparisons show that there is a significant difference between the mean of the resource leveling objective functions for all the solution methods. In other words, goal programming statistically outperforms other solution methods in terms of the resource leveling objective function. This is not the case for the other objective functions and CPU times. In addition, results of the VIKOR method indicate that the goal programming method outperforms the other solution methods. Hence, goal programming method is used to perform some sensitivity analyses with respect to the main parameters of the problem. Results show that by improving any of the parameters at least one objective function improves. However, due to the conflicting nature and the impact of weights of objective functions, in most cases, the trend are not constant to describe a general pattern.

    Keywords: Project Portfolio Selection, Multi-mode Resource Constrained Project Scheduling Problem (MRCPSP), Multi-objective optimization, Resource Leveling, Time-Varying Resource Consumption, Time Value of Money
نکته
  • نتایج بر اساس تاریخ انتشار مرتب شده‌اند.
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