به جمع مشترکان مگیران بپیوندید!

تنها با پرداخت 70 هزارتومان حق اشتراک سالانه به متن مقالات دسترسی داشته باشید و 100 مقاله را بدون هزینه دیگری دریافت کنید.

برای پرداخت حق اشتراک اگر عضو هستید وارد شوید در غیر این صورت حساب کاربری جدید ایجاد کنید

عضویت
جستجوی مقالات مرتبط با کلیدواژه

mixed integer programming

در نشریات گروه صنایع
تکرار جستجوی کلیدواژه mixed integer programming در نشریات گروه فنی و مهندسی
  • زهرا عرب زاده نصرت آباد، فرید ممیزی*، نادر غفاری نسب
    هدف

    در این تحقیق به بررسی مساله مکان یابی هاب مدولار پرداخته شده است که هدف آن کاهش هزینه حمل ونقل در شبکه هاب با در نظر گرفتن واحدهای حمل در شبکه می باشد. مدل ارایه شده با تعیین مکان هاب ها و نحوه تخصیص سایر گره های شبکه (گره های غیرهاب) به هاب های شبکه، به محاسبه بهینه واحدهای حمل به عنوان مثال تعداد پرواز هواپیماها در صنعت هوایی یا تعداد دفعات تردد کامیون ها در صنعت جاده ای در مسیرهای شبکه با در نظر گرفتن ظرفیت مناسب برای هر وسیله نقلیه می پردازد. همچنین تصمیم گیری در خصوص میزان درصد حجم جریان ارسالی در مسیرهای شبکه توسط مدل ریاضی صورت می گیرد.

    روش شناسی پژوهش: 

    مدل برنامه ریزی ریاضی شامل تابع هدف و محدودیت های مربوطه برای مساله موردنظر تعریف شده و توسط نرم افزار گمز حل شده و تاثیر پارامترهای مختلف بر روی نتایج بررسی شده است. زمان حل توسط نرم افزار گمز در اندازه نمونه های بزرگ تر به شدت افزایش می یابد؛ بنابراین، یک روش حل ابتکاری جدید مبتنی بر روش آزادسازی خطی متغیرهای عدد صحیح برای مساله توسعه داده شده است که قادر است جواب های نزدیک به بهینه در مدت زمان کمتر به دست آورد.

    یافته ها

    مدل ریاضی توسعه داده شده بر روی مجموعه داده های حمل ونقل مسافری هوایی مربوط به فرودگاه های کشور آمریکا که به مجموعه داده CAB معروف است، پیاده سازی شده است. نتایج حاصل نشان دهنده مکان بهینه هاب ها و همچنین تعداد بهینه واحدهای حمل ونقل بر روی یال های شبکه می باشد که وابسته به ظرفیت وسایل حمل ونقل می باشند.

    اصالت/ارزش افزوده علمی:

     در این پژوهش، یک مدل ریاضی عدد صحیح مختلط برای مساله مکان یابی هاب مدولار چند تخصیصه ارایه شده است. محاسبات عددی با کمک نرم افزار گمز انجام یافته و نتایج موردبحث و بررسی قرار گرفته است.

    کلید واژگان: مکان یابی هاب مدولار، چند تخصیصه، مدل برنامه ریزی عدد صحیح مختلط، آزادسازی خطی
    Zahra Arabzadeh Nosrat Abad, Farid Momayezi *, Nader Ghaffarinasab
    Purpose

    In this research, a modular hub location problem has been investigated where the objective is to reduce the transportation costs in the hub network. The proposed model determines the location of hubs, allocation of the non-hub nodes to the hubs, and the optimal vehicle traffic, i.e., the number of flights or the number of trucks traveling in the network, considering the appropriate capacity for each vehicle. Also, decisions regarding the percentage of the traffic volume sent via multiple network routes are made by the presented model.

    Methodology

    The mathematical model, including the objective function and constraints, is constructed and solved by GAMS software. The effect of different parameters on the results is investigated. Due to long solution times for the MIP model, a heuristic solution method based on LP relaxation of the integer variables is developed for the proposed problem, which is able to obtain near-optimal solutions in less time.

    Findings

    The developed mathematical model is implemented on the air passenger transportation data for the airports of the United States of America, which is known as the CAB data set. The results give the optimal number of hubs, as well as the optimal number of transportation units on each arc of the network, which depend on the capacity of the means of transportation.

    Originality/Value:

     In this research, a mixed integer programming model is developed for the multiple allocation modular hub location problem. Numerical experiments are conducted with the use of GAMS software and the results are discussed.

    Keywords: Modular Hub Location, Multiple Allocation, Mixed Integer Programming, LP Relaxation
  • Zahra Zanjani Foumani, Ensieh Ghaedy heidary, Amir Aghsami, Masoud Rabbani

    This paper proposes a bi-objective model for a green closed-loop supply chain network design. Four levels for forward and five levels for reverse flow were considered, including plants, distribution centers, online retailers, traditional retailers and customers for forward flow and customers, collecting centers, disposal centers, repair centers and plants for the reverse flow. The objectives are minimizing the GHG emission and maximizing profit by considering defective products and a second market for these products. Also, online retailers were considered alongside with traditional ones, since the Covid-19 pandemic has led to increase in the amount of online shopping. GAMS software and the Lpmetric technique were used to solve the model in the small and medium sizes. However, for the large size, we used Grasshopper Optimization Algorithm (GOA) as a meta-heuristic approach since solving the large size problem with GAMS is a complicated and time-consuming process. We provided Numerical and computational results to prove the efficiency and feasibility of the presented model. Finally, the managerial insights and future works were provided.

    Keywords: CO2 emission, Defective product, Grasshopper Optimization Algorithm (GOA), Green Closed-loop supply chain, Mixed-integer programming
  • فاطمه پایدار، مرضیه امینی رارانی، محمدسعید جبل عاملی*

    صنعت کاشی و سرامیک یکی از مشاغل قدیمی ایرانیان است که در هر دوره‌ی تاریخی به اشکال متفاوت به‌کار گرفته شده ‌است. ایران یکی از پنج کشور بزرگ تولیدکننده‌ی کاشی و سرامیک است که با دارا بودن ظرفیت بسیار زیاد در این صنعت توانسته است‌ به‌عنوان بزرگترین صادرکننده‌ی این محصولات در غرب آسیا شناخته‌ شود. در سال‌های اخیر صادرات کاشی و سرامیک یکی از مهم‌ترین دادوستدهای خارجی کشور شده ‌است. لذا برای دستیابی به بخش بزرگتری از سهم صادرات، فضای رقابتی بر این صنعت حاکم شده ‌است. از سوی دیگر امروزه مدیریت زنجیره‌تامین به‌دلیل افزایش جهانی شدن صنایع و رقابت‌های بین‌المللی بیش از پیش مورد توجه واقع شده ‌است. بسیاری از شرکت‌ها ترجیح می‌دهند، بخش‌های تدارکات، تامین، تولید و توزیع خود را به‌صورت مجزا در چندین کشور قرار دهند و مدیریت کنند. بنابراین در برخورد با رقابت‌های جهانی، چگونگی طراحی یک شبکه زنجیره‌تامین با حداقل هزینه و با تاکید بر ملاحظات مالی، بیمه و هزینه‌های گمرکی به یک مساله مهم برای شرکت‌های چندملیتی تبدیل شده ‌است. در این مقاله با به‌کارگیری روش برنامه‌ریزی مختلط عدد صحیح، یک مدل مکان‌یابی جهانی چهار سطحی چندهدفه با درنظر گرفتن محدودیت آب مصرفی در خطوط تولید ارایه شده و با استفاده از نرم‌افزار گمز حل و مورد بررسی قرار گرفته است. مدل پیشنهادی در یکی از صنایع تولیدی کاشی و سرامیک استان یزد جهت صحت سنجی مدل و بررسی تاثیر پارامترهای مهم بر تصمیمات استراتژیک مکان‌یابی به‌کار گرفته شده است که منجر به مکان‌یابی دو انبار داخلی و سه مرکز توزیع خارجی در کشورهای مجاور شد.

    کلید واژگان: طراحی شبکه زنجیره تامین جهانی، مکانیابی تسهیلات بین المللی، زنجیره تامین کاشی و سرامیک، برنامه ریزی مختلط عدد صحیح
    Fatemeh Paydar, Marzieh Aminirarani, Mohammad Jabalameli*

    The ceramic and tile industry is one of the traditional Iranian jobs used in every historical period of different forms. Iran is one of the five largest producers of tiles and ceramics, which have been able to become the biggest exporter of these products in Western Asia by having a huge capacity in the industry. In recent years, ceramics and tiles exports have become one of the country's most important foreign trade. Therefore, to achieve a larger part of the export share, the competitive environment has dominated the industry. On the other hand, supply chain management is considered more and more attention due to the increasing globalization of industries and international competition. Many companies prefer to supply and manage their procurement, production and distribution sectors separately in several countries. Therefore, in dealing with global competitiveness, how to design a supply chain network with minimum cost and with emphasis on financial considerations, insurance and customs, has become an important issue for multinational companies. In this paper, using mixed integer programming method, a four level global positioning model is proposed considering the limitation of water consumption in the production line using GAMS software. The proposed model was used in one of the ceramic tile manufacturing industries in Yazd province to validate the model and investigate the effect of important parameters on strategic location decisions, which led to the location of two domestic warehouses and three foreign distribution centers in neighboring countries.

    Keywords: Global supply chain design, International facility location, Ceramic tile supply chain, Mixed Integer Programming
  • Mahdi Yousefi Nejad Attari, Sajjad Ebadi Torkayesh, Ali Ebadi Torkayesh *
    This paper designs an optimization model for the emergency department of a hospital, considering related costs, nursing staff satisfaction, and waiting time for several diseases concerning the number of staff in each shift. This study's primary purpose is to minimize the related costs, maximize nursing staff satisfaction, and allocate nursing staff to working shifts in the emergency department. In the first stage, a simulation model is constructed based on the emergency department's status with ARENA 14 software. Then, the model is investigated under three different scenarios. In the second stage, mixed-integer programming is proposed to minimize the costs, nursing staff satisfaction and optimally allocate nurses to various shifts. Furthermore, the generalized center method is used to solve the model by converting the multi-objective model to a single-objective one. In Tabriz, Iran, Imam Reza hospital is considered our case study investigated by simulation and MIP models. Finally, the results of simulation and mathematical models demonstrate that six new nurses should be added to the emergency department.
    Keywords: Staff assignment, Service time, Simulation, Mixed-integer programming, Generalized center method
  • Lorena Pradenas *, German Bravo, Rodrigo Linfati
    Sawmills are an important part of the forest supply chain, and as at any company, their production planning is highly complex. Planning in the remanufacturing area, in terms of its economic contribution to the sawmill and the supply chain, has not been studied in the scientific literature. The goal of this study was to develop and solve a mixed-integer linear programming model by employing an efficient allocation of cutting patterns on in-stock logs to maximize profits. To quantify the impact of an appropriate use of raw materials in the remanufacturing area in a sawmill, real and generated data were used. The model considers fixed and variable production costs, the availability of raw material, the capacity of the processes, the sale price of the products and the demand, for a process period of one month. The proposed compact mixed-integer linear programming model was solved using the commercial solver IBM ILGO CPLEX12.8. It was determined that the additional margin in USD earned in the remanufacturing area for the considered scenarios amounted to an average of 21.6%. The proposed method facilitates evaluating the economic contribution of remanufacturing while identifying bottlenecks and assessing proposed scenarios.
    Keywords: Forest industry, Planning in sawmills, Tactical planning, Mixed Integer Programming, Forest optimization
  • محمد مهدی نصیری*، سمانه کرلو

    یکی از مسایلی که جوامع شهری با آن روبه رو هستند مدیریت زباله است. در این مقاله، مکان های دفن زباله ها، ظرفیت این مکان ها، مکان ایستگاه های انتقال، ظرفیت آن ها و مکان محل های بازیافت زباله را به گونه ای تعیین می کنیم که کل هزینه (شامل هزینه های احداث مراکز، حمل ونقل زباله از محل تولید تا محل پالایش، دفن و بازیافت) حداقل شود. هم چنین، برای رعایت محدودیت های زیست محیطی با تعریف کردن حداکثر مجاز آلودگی برای هر مرکز جمعیت، میزان آلودگی را کنترل می کنیم. در این پژوهش، مسئله به صورت یک مدل برنامه ریزی عدد صحیح آمیخته فرمول بندی شده است. سپس ظرفیت محل دفن و ظرفیت محل پالایش غیرقطعی در نظر گرفته شده و مدل به صورت بهینه سازی استوار توسعه یافته است. همچنین برای اعتبارسنجی مدل، یک مسئله نمونه حل شده و نتایج محاسباتی به ازای سطوح متفاوتی از محافظه کاری ارایه گردیده است. تصمیم گیرنده می تواند از این نتایج برای انتخاب سطح محافظه کاری مناسب استفاده نماید.

    کلید واژگان: مدیریت زباله شهری، مکان یابی محل دفن زباله، بهینه سازی استوار، برنامه ریزی عدد صحیح آمیخته
    MohammadMahdi Nasiri *, Samaneh Korlou

    One of the issues facing urban communities is waste management. In this paper, we determine the location of landfills, the capacity of these sites, the location of transfer stations, their capacity, and the location of waste recycling centers in such a way that the total costs (including the costs of establishment and transportation of waste from production to refining sites, landfills and recycling centers) are minimized. We also control pollution levels by defining a maximum allowable pollution for each population center to comply with environmental constraints. In this study, the problem is formulated as a mixed integer programming model. Then, the capacity of the landfill and the capacity of the refining sites are considered as uncertain parameters and a robust optimization model is developed. Also, to validate the model, a problem instance is solved and the computational results are presented for different levels of conservatism. The decision maker can use the results to select the appropriate level of conservatism.

    Keywords: Urban waste management, Landfill location, Robust Optimization, Mixed Integer Programming
  • Sepideh Khalafi, Ashkan Hafezalkotob *, Davood Mohamaditabar, MohammadKazem Sayadi

    Recently, following the raise in expense pressures led to lower economic growth, an increasing number of manufacturers have begun to investigate eventuality of handling returned product in a more cost-effective and proper procedure. Significance of Reverse Logistics (RL) is becoming greater due to various governmental, societal, and environmental reasons. Number of papers present in the literature on RLs is a well index of its importance. In some industries, appropriately collected returned products could be used as raw material for another product, increasing Supply Chain (SC) profits and reducing the waste. Since, perishable goods have a limited shelf -life, they can be reusable if they are collected before they reach a critical time. Accordingly, in the present study, a Mixed Integer Linear Programming (MILP) model was introduced for a network of closed-loop SC with recycling of returned perishable goods, involving suppliers, producers, retailers, together with collection and disposal centers, in a multi-product, multi-period, and multi-level basis. To do this, a case study was performed on milk and yogurt products of a company in dairy industry. The model was solved and analyzed using GAMS software. Results obtained from assessment of the model indicated that, timely collection of perishable goods and their use in production of new products reduces total costs of perishable SC network.

    Keywords: Closed-loop supply chain, forward, reverse logistics, mixed integer programming, perishable products
  • معصومه حسین پور*، علیرضا فخارزاده جهرمی
    در دهه های اخیر نظریه ی بهینه سازی استوار (مقاوم) به عنوان ابزاری توانمند جهت بهینه یابی فرآیندهای غیرقطعی معرفی کرده است. نظربه قطعی نبودن میزان بارگلیسمی مواد غذایی مصرفی، هدف اصلی این مقاله تهیه ی رژیم غذایی بهینه ایرانی با استفاده از بهینه سازی استوار به منظور تنظیم بارگلیسمی در بیماران مبتلا به دیابت نوع 2 است. این درحالی است که دیابت نوع 2 یکی از بیماری های ویرانگری است که علاوه بر بیماری های قلبی-عروقی، عفونی و کلیه، مقاومت به انسولین و سرطان را در پی دارد و و داروهای کاهش دهنده ی کلسترول، خطر عوارض قلبی-عروقی و حتی ابتلا به سرطان را در خود دارند. در این راستا، تنظیم تغذیه در پیشگیری، کنترل و جلوگیری یا کاهش عوارض حاصل از دیابت نقش مهمی دارد. در این تحقیق پس از جمع آوری اطلاعات تغذیه ای لازم، به جهت عدم قطعیت بارگلیسمی غذاها، مدل رژیم غذایی ایرانی را با استفاده از روش بهینه سازی استوار تعیین و مورد تحلیل قرار داده ایم. بر این اساس، 75 نوع غذا (42 غذای ایرانی، 10 ماده غذایی جهت صبحانه، 20 نوع میوه و آب میوه و3 نوع لبنیات) به صورت بومی مورد مطالعه قرار گرفته است. از مزایای این مدل، توانایی تطبیق بر اساس سلیقه ی شخص و نظر متخصص تغذیه با هدف کمینه سازی تغییرات رژیم غذایی فعلی فرد می باشد.
    کلید واژگان: رژیم غذای ایرانی، شاخص و بارگلیسمی، بهینه سازی استوار (مقاوم)، برنامه ریزی عدد صحیح آمیخته
    Masomeh Hoseinpour *, Alireza Fakharzadeh Jahromi
    In recent decades, the theory of robust optimization has been introduced as a powerful tool for optimizing uncertain processes. Regarding the Uncertainty of the glycemic load of consumed food, the main purpose of this article is to provide an optimal Iranian diet using a robust optimization to adjust the glycemic load in patients with type 2 diabetes. Diabetes type 2 is a devastating disease, in addition to cardiovascular disease, infectious and kidney diseases, causes insulin resistance and cancer and drugs of cholesterol-lowering have an increased risk of cardiovascular complications and incidence of cancer. Indeed, adjustment of nutrition is important to prevent and control or reduce the complications of diabetes. In this paper, due to the uncertainty of the glycemic load of foods, with collecting necessary nutritional information, the Iranian diet model is determined and analyzed by robust optimization method. According to this, 75 cases of food (42 Iranian food, 10 Foodstuffs for breakfast, 20 types of fruits and Fruit juices and 3 types of dairy products) have been studied locally. The benefits of this model are the ability to adapt according to the person's tastes and opinion of the nutritionist with minimizing changes for the current diet of the individual.
    Keywords: Iranian diet, Glycemic index, load, robust optimization, Mixed-Integer Programming
  • Ashkan Teimouri *, Mahdi Bashiri
    Wildfires are of the forest-related disasters caused by inhumane factors. Spreading of these fires is due to the increase of the density of flammable plants. Two important approaches to prevent this occurrence are fuel treatment and fire suppression resources preparedness. In this paper, a mixed integer programming model is proposed based on the covering location and assignment problems which seeks fuel reduction over a multi period of time in a forest area, along with fire suppression resources preparedness and dispatch of firefighters in the last period. One of the forest areas in northern Iran was considered to fuel treatment and fire suppression resources preparedness and assuming the growth of vegetation species varies in different parts, the region is separated into distinct and discrete network points. Obtained results of the model solving show an increase in the vegetation cover volume and reduction of the risk of fire.
    Keywords: Covering location problem, mixed integer programming, wildfires, fuel treatment, suppression resources
  • Amir Ebrahimzadeh Pilerood, Mehdi Heydari *, Mohammad Mahdavi Mazdeh
    In this paper, the problem of two-machine flow shop scheduling to minimize total energy costs under time-of-use tariffs is investigated. As the objective function of this study is not a regular measure, allowing intentional idle-time can be advantageous. So this study considers two approaches, one for non-delay version of the problem and the other one for a situation when inserting intentional idle time is permitted. A mixed integer linear programming is formulated to determine the timing of jobs in order to minimize total energy costs while idle time insertion is allowed. For the non-delay version of the problem, a branch-and-bound algorithm is presented. A lower bound and several dominance properties are used to increase the speed of the branch-and-bound algorithm. Computational experiments are also given to evaluate the performance of the algorithm. Based on results, the proposed algorithms can optimally schedule jobs in small size samples but by increasing the number of jobs from 15 and cost periods from 3, the performance of branch-and-bound has been decreased.
    Keywords: Flow shop scheduling, mixed integer programming, branch-and-bound, time-of-use energy costs, idle time insertion
  • سیدمحمدتقی فاطمی قمی*، واحد اداک، فریبرز جولای
    در این مقاله مسئله ی توالی عملیات برروی ماشین های موازی یکسان با معیار کمینه سازی مجموع دیرکرد کل کارها بررسی می شود. مدل برنامه ریزی عدد صحیح مختلط کارایی برای مسئله ی مورد نظر ارائه می شود؛ سپس مدلی پیشنهادی برای به دست آوردن حد پایین بهتر و کاراتر از یکی از حدود پایین موجود در پیشینه ی پژوهش های مسئله ارائه می شود. مسئله ی ماشین های موازی یکسان با تابع هدف کمینه سازی مجموع دیرکرد کل کارها تعمیم یافته ی مسئله ی تک ماشینی است و این مسئله جزء مسائل N P-h a r d دسته بندی می شود. از این رو مدل ارائه شده توانایی حل بهینه ی مسائل با اندازه ی بزرگ در زمان منطقی را ندارد. به همین دلیل برای حل مسئله در اندازه های متوسط و بزرگ و نیز ارزیابی کارایی حدپایین به دست آمده از مدل پیشنهادی و حد پایین موجود در پیشینه، الگوریتم فراابتکاری شبیه سازی تبرید اصلاح شده یی که برای اولین بار از عملگر تقاطع و جهش برای ایجاد جواب همسایگی بهره می برد، ارائه می شود.
    کلید واژگان: ماشین های موازی، مجموع دیرکرد کل کارها، الگوریتم شبیه سازی تبرید اصلاح شده، برنامه ریزی عدد صحیح مختلط
    S.M.T. Fatemi Ghomi *, V. Adakb, F. Jolai
    Determining e ective scheduling in operations sequence is among the important problems of production scheduling. This paper deals with the problem of minimizing total tardiness on a parallel machine with N jobs and m machines. In the literature, there is a lack of suitable mathematical programming of the problem. Hence, this paper presents a mixed integer mathematical model for the problem. Since the problem has been proved as an NP-hard problem, it would be valuable to give a lower bound (LB) with a reasonable computational time. Denoting the processing time of a typical job on the machine, the modi ed processing time would be .With this modi ed processing time, the problem can be seen as a single machine; namely, the original processing time is divided by the number of machines and the division is considered as the modi ed processing time for computations. The problem is reformulated as an assignment problem in which the positions of jobs in the sequence are the locations of the assignment problem. The model presents the lower bound of the problem. To compare thequality(runningtime)oftheintroducedLB,wegeneratedsomerandominstancesoftheproblemfromsmall to large sizes. The optimal solution of the small size instances is obtained through solving the developed mathematical model. To obtain the solution of the medium and large sized instances, a new simulated annealing algorithm is developed. In this algorithm, the crossover operator and mutation have been used to create a neighborhood of simulated annealing algorithm; but for the rst time the crossover operator is used to create neighborhood directly. The results gained from the lower bound are compared with those of lower bound available in the literature. They con rm that the lower bound introduced in this paper gives high quality solutions, and hence, it has superiority to the available LB in the literature.
    Keywords: Parallel machines, total tardiness, improved simulated annealing algorithm, mixed integer programming
  • Mansoureh Maadi *, Mohammad Javidnia
    Precedence constrained sequencing problem (PCSP) is related to locate the optimal sequence with the shortest traveling time among all feasible sequences. In PCSP, precedence relations determine sequence of traveling between any two nodes. Various methods and algorithms for effectively solving the PCSP have been suggested. In this paper we propose a cuckoo search algorithm (CSA) for effectively solving PCSP. CSA is inspired by the life of a bird named cuckoo. As basic CSA at first was introduced to solve continuous optimization problem, in this paper to find the optimal sequence of the PCSP, some schemes are proposed with modifications in operators of the basic CSA to solve discrete precedence constrained sequencing problem. To evaluate the performance of proposed algorithm, several instances with different sizes from the literature are tested in this paper. Computational results show the good performance of the proposed algorithm in comparison with the best results of the literature.
    Keywords: Precedence constrained sequencing problem, Mixed integer programming, Cuckoo search algorithm
  • Parviz Fattahi *, Mehdi Tanhatalab, Mahdi Bashiri
    One of the important aspects of distribution optimization problems is simultaneously, controlling the inventory while devising the best vehicle routing, which is a famous problem, called inventory-routing problem (IRP). When the lot-sizing decisions are jointed with IRP, the problem will get more complicated called production inventory-routing problem (PIRP). To become closer to the real life problems that includes products that have a limited life time like foods, it seems reasonable to narrow down the PIRP problem to the perishable products, which is perishable-production inventory-routing problem (P-PIRP). This paper addresses a P-PIRP in a two echelon supply chain system where the vendor must decide when and how much to produce and deliver products to the customer’s warehouse. Here, the general model of PIRP as mixed integer programming (MIP)is adopted and the perishability constraint are added in order to solve the P-PIRP problems. Due to the complexity of problem, providing solution for the medium to large instances cannot be easily achieved by business applications, and then using the meta-heuristics is unavoidable. The novelty of this research is devising an enhanced genetic algorithm (GA) using multiple repairing mechanisms, which because of its computationally cumbersomeness have absorbed less attention in the literature. The problem runs through some generated instances and shows superiority in comparison to the business application.
    Keywords: Production inventory routing problem, IRP, mixed integer-programming, perishable, Genetic Algorithm
  • مهدی سلطانی تهرانی*، مسعود مصدق خواه، حسینعلی حسن پور
    امروزه، توجه به لجستیک مستقیم و معکوس نقش بسیار مهمی در کاهش هزینه های زنجیره تامین ایفا می کند. در این مقاله به منظور ارائه یک شبکه زنجیره تامین حلقه بسته که شامل مراکز تامین، تولید، توزیع، جمع آوری، بازیافت و دفن و انهدام است از یک مدل خطی برنامه ریزی عدد صحیح مختلط استفاده شده است. این مقاله حالت چند دوره ای و چند محصولی را در زنجیره تامین چند سطحی در نظر گرفته و هزینه های پردازش نیز در مکان ها لحاظ شده است و کل کالاهای مرجوعی که قابلیت اصلاح دارند به مراکز تولید و توزیع منتقل می شوند تا در فرآیند لجستیک مستقیم به دست مصرف کننده برسند. هدف مدل کاهش هزینه های اجاره مراکز، هزینه های حمل و نقل بین مراکز و هزینه پردازش داخل مراکز می باشد. مدل پیشنهادی با استفاده از نرم افزار 3.CPLEX 12 در قالب یک مطالعه موردی حل گردیده است. مدل مربوطه براساس چند نمونه مسئله آزمایشی و همچنین براساس تعداد محصولات مختلف مورد تحلیل قرار گرفته و در پایان نتیجه گیری کلی ارائه شده است.
    کلید واژگان: زنجیره تامین حلقه بسته، لجستیک مستقیم و معکوس، برنامه ریزی عدد صحیح مختلط، لجستیک یکپارچه
    Mehdi Soltani Tehrani*, Masoud Mosaddeghkhah, Hosseinali Hassanpour
    Today, due to the direct and reverse logistics plays an important role in reducing the costs in supply chain. In this paper, in order to provide a closed-loop supply chain network including supply centers, production, distribution, collection, recycling and disposal of a used linear mixed integer programming. This paper to consider multi-period and multi-product in multi-level supply chain and processing costs are taken into account in place and Returned goods that can be improved will be transferred entirely to the production and distribution centers in the logistics process directly reach the hands of consumers. The model objective centers rent cost reduction in the supply chain and the cost of transportation between the centers and the processing cost is in centers. The proposed model using software CPLEX 12.3 in the form of a case study solved. Model based on some samples tested and analyzed based on the number of different products, and in the end conclusion was presented.
    Keywords: Closed Supply Chain, Direct, Inverse Logistics, Mixed Integer Programming, Integrated Logistics
  • Amir Hossein Parsamanesh*, Rashed Sahraeian
    Despite existing various integer programming for sequencing problems, there is not enough information about practical values of the models. This paper considers the problem of minimizing maximum lateness with release dates and presents four different mixed integer programming (MIP) models to solve this problem. These models have been formulated for the classical single machine problem, namely sequenceposition (SP), disjunctive (DJ), linear ordering (LO) and hybrid (HY). The main focus of this research is on studying the structural properties of minimizing maximum lateness in a single machine using MIP formulations. This comparison helps us know the characteristics and priority of different models in minimizing maximum lateness. Regarding to these characteristics and priorities, while solving the lateness problem in the procedure of solving a real-world problem, we apply the lateness model which yields in solution in shortest period of time and try not to use formulations which never lead to solution for large-scale problems. Beside single machine, these characteristics are applicable to more complicated machine environment. We generate a set of test problems in an attempt to solve the formulations, using CPLEX software. According to the computational results, a detailed comparison between proposed MIP formulations is reported and discussed in order to determine the best formulation which is computationally efficient and structurally parsimonious to solve the considering problem. Among the four presented formulations, sequence-position (SP) has the most efficient computational time to find the optimal solution.
    Keywords: Single machine scheduling, Mixed integer programming, Maximum lateness, Release date
  • Majid Yousefikhoshbakht, Frazad Didehvar, Farhad Rahmati
    The heterogeneous fixed fleet open vehicle routing problem (HFFOVRP) is one of the most significant extension problems of the open vehicle routing problem (OVRP). The HFFOVRP is the problem of designing collection routes to a number of predefined nodes by a fixed fleet number of vehicles with various capacities and related costs. In this problem, the vehicle doesn’t return to the depot after serving the last customer. Because of its numerous applications in industrial and service problems, a new model of the HFFOVRP based on mixed integer programming is proposed in this paper. Furthermore, due to its NP-hard nature, an ant colony system (ACS) algorithm was proposed. Since there were no existing benchmarks, this study generated some test problems. From the comparison with the results of exact algorithm, the proposed algorithm showed that it can provide better solutions within a comparatively shorter period of time.
    Keywords: Open Vehicle Routing Problem, Heterogeneous fleet, Ant Colony System, Exact Algorithm, Mixed Integer programming
  • مصطفی ستاک، وحید عزیزی، حسین کریمی
    در مدلسازی مسائل دنیای واقعی باید تا حد ممکن تمامی محدودیت های حاکم بر مساله را در نظر گرفت. این رویکرد در مدلسازی سبب می شود تا جواب حاصل از مدل شدنی بوده و تا حد زیادی نزدیک به آنچه در عمل رخ می دهد، باشد. بنابراین باید به دنبال ایجاد مدل های قابل اطمینانی بود که پاسخگوی تعداد قابل قبولی از محدودیت های موجود در هر مساله مورد بررسی باشند، که صرفا جنبه تئوری نداشته و در عمل نیز پرکاربرد باشند. در این مقاله مدلی ریاضی طراحی می گردد که پاسخگوی شرایطی خاص با محدودیت های گوناگون و در عین حال کاربردی در حوزه مسائل مکانیابی- مسیریابی است. مساله اشاره شده، مساله مکان یابی مسیریابی چنددپویی ظرفیت دار با برداشت و تحویل همزمان و بارهای برش یافته است. این تحقیق بیشتر بر ویژگی برش تاکید می کند که در عمل نیز به وفور قابل مشاهده است. برش هنگامی رخ می دهد که تقاضای برخی از مشتریان از ظرفیت هر کدام از وسایل نقلیه موجود بیشتر باشد. در این مقاله یک مدل برنامه ریزی عدد صحیح مختلط برای این مساله ارائه می شود. سپس دو روش فراابتکاری ترکیبی برای حل مساله در ابعاد بزرگ پیشنهاد می شود. الگوریتم اول مبتنی بر الگوریتم ژنتیک گسسته و ژنتیک پیوسته است که به اختصار DCGA نامیده می شود و روش دوم براساس ژنتیک گسسته و الگوریتم بهینه سازی تجمعی ذرات است که DGAPSO نام دارد. در نهایت نتایج عددی حاصل از حل مسائل نمونه با استفاده از حل کننده سیپلکس و روش های پیشنهادی ارائه می شود. تجزیه و تحلیل نتایج آزمایشات موثر بودن الگوریتم های پیشنهادی به خصوص DGAPSO را نشان می دهد.
    کلید واژگان: مکانیابی، مسیریابی، برداشت و تحویل همزمان، برش، برنامه ریزی عدد صحیح مختلط، الگوریتم ژنتیک
    Mostafa Setak, Vahid Azizi, Hossein Karimi
    Problems in real world include various constraints. So the reliable models should be designed that satisfy the reasonable number of these constraints. These models should be applicable. In this paper، regarding the mentioned circumstances، we design a model for multi depots capacitated location-routing problem with simultaneous pickup and delivery and split loads. The paper emphasis is on the split property that happens when demand of a customer exceeds vehicle capacity. We propose a mixed integer-programming model. Also we develop two metaheuristics for solving large scale instance problems. The first approach is based on discrete genetic algorithm and continuous genetic algorithm and the second one is based on discrete genetic algorithm and particle swarm optimization. Results of solving instance problems by CPLEX solver and proposed DCGA and DGAPSO algorithms show that both algorithms are effective and DGAPSO outperforms DCGA in solution quality and computation times.
    Keywords: Location, Routing, Simultaneous Pickup, Delivery, Split, Mixed Integer Programming, Genetic Algorithm
  • ابراهیم رضایی نیک، مهرداد یزدان پناه *، محمدتقی اسعدی، زهرا محمودی یکتا
    فرابارانداز یک استراتژی لجستیکی و در نقش گره ای میانی در شبکه توزیع زنجیره تامین است. در قسمت لجستیک، نگهداری موجودی جزو هزینه برترین قسمت ها می باشد که فرابارانداز علاوه بر کاهش هزینه نگهداری، موجب کاهش هزینه های جمع آوری سفارش، حمل ونقل و مدت زمان ارسال می شود. محصولاتی که از تامین کنندگان مختلف توسط بارکش های ورودی به فرابارانداز می رسند، با کمترین مقدار و ذخیره سازی ممکن و با دسته بندی های متناسب با تقاضای مشتری، در مدت زمانی عموما کمتر از 24 ساعت، بر روی بارکش های خروجی بارگذاری می شوند. در این مقاله، یک مدل عدد صحیح مختلط برای مدل سازی فرابارانداز با چندین درب ورودی و خروجی ارائه شده است که به طور هم زمان تخصیص بارکش های ورودی و خروجی به درب ها، توالی خدمت گیری آنها و هم چنین تخصیص محصولات از بارکش های ورودی به بارکش های خروجی می پردازد. مدل پیشنهاد شده در یکی از واحدهای صنعتی پیاده سازی شده و نتایج آن که بیانگر کارایی مدل در دنیای واقعی می باشد، ارائه گردیده است.
    کلید واژگان: فرابارانداز، لجستیک، کاهش هزینه های انبارداری، زمان بندی بارکش ها، برنامه ریزی عدد صحیح
    Ebrahim Rezaee Nik, Mehrdad Yazdanpanah *, Mohmmad Taghi Asadi, Zahra Mahmoodi Yekta
    Cross docking is a logistic strategy that plays the role of a middle knot in distribution network in the provision process. In logistic part, inventory holding is considered as an important matter in managing costs. Not only cross docking reduces the inventory holding cost, but it also reduces the cost of collecting received orders, transportation and duration of sending. The products, which are unloaded on cross docking by inbound trucks, are classified properly according to customers’ orders and loaded on outbound trucks with minimum possible saving and as soon as possible, usually less than 24 hours. A model is offered in this paper on the basis of a mixed integer programming to model the cross docking with several receiving and shipping doors. It allocates different doors to inbound and outbound trucks, regards the loading sequences, and also allocates products from importing trucks to exporting ones coincidentally. The proposed model has been implemented in the dairy industry, and the results indicate the effectiveness of the model is presented in the real world.
    Keywords: Cross Docking, Logistics, Reducing Storage Costs, Truck Scheduling, Mixed Integer Programming
  • Bahman Naderi
    This paper investigates the problem of selecting and scheduling a set of projects among available projects. Each project consists of several tasks and to perform each one some resource is required. The objective is to maximize total benefit. The paper constructs a mathematical formulation in form of mixed integer linear programming model. Three effective metaheuristics in form of the imperialist competitive algorithm, simulated annealing and genetic algorithm are developed to solve such a hard problem. The proposed algorithms employ advanced operators. The performance of the proposed algorithms is numerically evaluated. The results show the high performance of the imperialist competitive algorithm outperforms the other algorithms.
    Keywords: Project portfolio selection, scheduling, imperialist competitive algorithm, Simulated annealing, genetic algorithm, mixed integer programming
  • Dr Ali Shahandeh Nookabadi, Mr Mohammad Reza Yadoolahpour, Mrs Soheila Kavosh
    Network location models comprise one of the main categories of location models. These models have various applications in regional and urban planning as well as in transportation, distribution, and energy management. In a network location problem, nodes represent demand points and candidate locations to locate the facilities. If the links network is unchangeably determined, the problem will be an FLP (Facility Location Problem). However, if links can be added to the network at a reasonable cost, the problem will then be a combination of facility location and NDP (Network Design Problem); hence, called FLNDP (Facility Location Network Design Problem), a more general variant of FLP. In previous studies of this problem, capacity of facilities was considered to be a constraint while capacity of links was not considered at all. The proposed MIP model considers capacity of facilities and links as decision variables. This approach increases the utilization of facilities and links, and prevents the construction of links and location of facilities with low utilization. Furthermore, facility location cost (link construction cost) in the proposed model is supposed to be a function of the associated facility (link) capacity. Computational experiments as well as sensitivity analyses performed indicate the efficiency of the model.
    Keywords: Network Location, Network Design Problem, Mixed Integer Programming, Facility Location, Link, Capacity
نکته
  • نتایج بر اساس تاریخ انتشار مرتب شده‌اند.
  • کلیدواژه مورد نظر شما تنها در فیلد کلیدواژگان مقالات جستجو شده‌است. به منظور حذف نتایج غیر مرتبط، جستجو تنها در مقالات مجلاتی انجام شده که با مجله ماخذ هم موضوع هستند.
  • در صورتی که می‌خواهید جستجو را در همه موضوعات و با شرایط دیگر تکرار کنید به صفحه جستجوی پیشرفته مجلات مراجعه کنید.
درخواست پشتیبانی - گزارش اشکال