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کاربرد نوع شرط:
- جایگاه : پژوهشی
- مجله: Journal of Information Technology Management
- نوع مقاله: Journal Article
- کلمات کلیدی: Internet,Epidemic model,Mass Media,News & Information Diffusion,Stochastic process
- چکیده:
- چکیده انگلیسی: Because of the newness of Information Technology (IT) and Internet in the world, and because of intrinsic constraint of multimedia and traditional news systems such as: newspaper, bulletin, radio and television in interactive communication, diffusion of news and information in Internet has possessed special situation. But it is possible sometimes that the use of internet doesn’t achieve anticipated and expected objectives for leaders of media. Because every media is appropriate to fulfill special objectives. Namely, sometimes using the Internet and occasionally using the mass media, can be efficient. In this article, it is tried with using stochastic process and adapting epidemic model for mass media behavior and also introducing a new mathematic method for analyzing Internet behavior concerning diffusion news in a period of time and the behavior of media is analyzed. Therefore, some features such as: the mean number of person hears news, the mean of time continues to hear news N-person, and other important parameters are studied.
- انتشار مقاله: 11-10-1348
- نویسندگان: Seyed Golamreza Jalali Naeeni,Saeed Yaghoubi,Fateme Pourdadashi Komachali
- مشاهده
- جایگاه : پژوهشی
- مجله: Journal of Industrial Engineering International
- نوع مقاله: Journal Article
- کلمات کلیدی: Project management,Queuing,Multi-class dynamic PERT network
- چکیده:
- چکیده انگلیسی: This investigation presents a heuristic method for consumable resource allocation problem in multi-class dynamic Project Evaluation and Review Technique (PERT) networks, where new projects from different classes (types) arrive to system according to independent Poisson processes with different arrival rates. Each activity of any project is operated at a devoted service station located in a node of the network with exponential distribution according to its class. Indeed, each project arrives to the first service station and continues its routing according to precedence network of its class. Such system can be represented as a queuing network, while the discipline of queues is first come, first served. On the basis of presented method, a multi-class system is decomposed into several single-class dynamic PERT networks, whereas each class is considered separately as a minisystem. In modeling of single-class dynamic PERT network, we use Markov process and a multi-objective model investigated by Azaron and Tavakkoli-Moghaddam in 2007. Then, after obtaining the resources allocated to service stations in every minisystem, the final resources allocated to activities are calculated by the proposed method.
- انتشار مقاله: 10-07-1399
- نویسندگان: Saeed Yaghoubi,Siamak Noori,Mohammad Mahdavi Mazdeh
- مشاهده
- جایگاه : پژوهشی
- مجله: Journal of Industrial and Systems Engineering
- نوع مقاله: Journal Article
- کلمات کلیدی: network design,Health Systems,Blood plasma supply chain,scenario-based optimization
- چکیده:
- چکیده انگلیسی: Blood plasma is a yellowish liquid component of blood that holds the blood cells (red blood cells, white blood cells, and platelets) in whole blood in suspension. Plasma is human-based so that it just makes in the body thus only donors can be the source for preparing plasma. Plasma has usage in two-part therapy and medicine. This article addresses the design of an integrated blood plasma supply chain network considering demand in two segments of therapy and medicine. To this goal, a MILP scenario-based mathematical programming model is developed which minimizes the total cost as well as the unsatisfied demand. After that, the actual data of a case study are used to illustrate the applicability also the performance of the offered model as well as validation. The obtained results show the superiority of the recovered plasma method compared to the apheresis plasma method for the blood transmission network. As well, the maximum use of the capacity instantly after the opening of each collection centers is beneficial for reducing the total cost.
- انتشار مقاله: 18-10-1398
- نویسندگان: Habib Dehghani Ashkezari,Saeed Yaghoubi
- مشاهده
- جایگاه : پژوهشی
- مجله: Journal of Industrial and Systems Engineering
- نوع مقاله: Journal Article
- کلمات کلیدی: Supply Chain Coordination,Pharmaceutical products,buy back contract
- چکیده:
- چکیده انگلیسی: Drug has a great and crucial role inboth the health systems and the quality of life, and thereforeits shortage can cause death.In order to the important role of drugs,pharmaceutical supply chain(PSC) shouldensure that drugs are delivered to people in the right time with the best quality.On the other hand, thesupply chain (SC) members depend on each other for resources and information, and it has increased in recent times due to outsourcing, globalization and rapid innovations in information technologies. This increase brings some extent of risk and uncertainty along with benefits for them and so, SC coordinationis a crucial issue. Thispaper studies a PSCmodel witha single active pharmaceutical ingredientsand a single finish pharmaceutical product. For this purpose, decentralized and centralized structures are investigated. Then,a coordination mechanism is developed based on the buyback contract in order to encouragethe SC members to make decision by considering each other's profit to simulate the condition of decentralized SC versus centralized one.In order to demonstrate the effect of the proposed coordination model, numerical examples and sensitivity analysis are provided. The results show that by applying buy back contract, in coordination structure the order amount of raw material and the profits of the pharmaceutical supply chain will increaseso it can effect on the amount of manufacturing orders.By using buy back contract, the profit of each SC member increasesin comparison with the decentralized decision-making structure.
- انتشار مقاله: 31-03-1396
- نویسندگان: Sayeh Foladi-Mahani,Saeed Yaghoubi,Seyyed-Mahdi Hosseini-Motlagh,Mohammadreza Nematollahi
- مشاهده
- جایگاه : پژوهشی
- مجله: Journal of Industrial and Systems Engineering
- نوع مقاله: Journal Article
- کلمات کلیدی: pricing,inventory model,Deteriorating and ameliorating items,Competing environment,Bertrand game
- چکیده:
- چکیده انگلیسی: This paper develops a pricing and inventory model of a supply chain composing one supplier and two manufacturers in which the supplier sells its product to two competing manufacturers. Each manufacturer faces a deterministic demand that depends on his/her own and the other competitor sale price. Selling price for the supplier is time dependent and increment function.Both amelioration and deterioration effects are seen simultaneously for this model. In this paper, it is assumed that shortages are not allowed in whichthe objective ismaximizing the total profit of supplier and manufacturers in two stages. In first stage, the total profit of supplier is maximized and then in the second stage, two manufacturers maximize their total profits with regard to the optimal decision variables obtained in the first stage. A case study of trout fish breeding is presented andnumerical example is solved by Mathematica optimization tool. Sensitivity analysis is finally conducted to study the effect of various parameters on the optimal solution.
- انتشار مقاله: 26-10-1395
- نویسندگان: Mohammadmahdi Malekitabar,Saeed Yaghoubi
- مشاهده
- جایگاه : پژوهشی
- مجله: Journal of Computational Applied Mechanics
- نوع مقاله: Journal Article
- کلمات کلیدی: Genetic Algorithm,Neural network,Hydromechanical Deep Drawing,Maximum Reduction in Sheet Thickness,Product Uniformity
- چکیده:
- چکیده انگلیسی: The present research work is concerned with the effects of optimum process variables in elevated temperature hydro-mechanical deep drawing of 5052 aluminum alloy. Punch-workpiece and die-workpiece friction coefficients together with the initial gap between the blank holder and matrix were considered as the process variables which, in optimization terminology, are called design parameters. Since both the maximum reduction in sheet thickness and the final product uniformity (thickness variation) are important in the hydro-mechanical deep drawing, they are selected as the objective functions for optimization. After conducting 27 finite-element simulations of the operation and validation of the numerical results, a neural network was trained and combined with the genetic algorithm to obtain the optimum design parameters. The outcomes of this investigation have shown that these optimized process variables simultaneously resulted in the best values for both the objective functions, in comparison with all the conducted finite-element analyses.
- انتشار مقاله: 11-09-1396
- نویسندگان: Saeed Yaghoubi,Faramarz Fereshteh-saniee
- مشاهده
- جایگاه : پژوهشی
- مجله: Journal of Computational Applied Mechanics
- نوع مقاله: Journal Article
- کلمات کلیدی: Genetic Algorithm,Neural network,Hydromechanical Deep Drawing,Maximum Reduction in Sheet Thickness,Product Uniformity
- چکیده:
- چکیده انگلیسی: The present research work is concerned with the effects of optimum process variables in elevated temperature hydro-mechanical deep drawing of 5052 aluminum alloy. Punch-workpiece and die-workpiece friction coefficients together with the initial gap between the blank holder and matrix were considered as the process variables which, in optimization terminology, are called design parameters. Since both the maximum reduction in sheet thickness and the final product uniformity (thickness variation) are important in the hydro-mechanical deep drawing, they are selected as the objective functions for optimization. After conducting 27 finite-element simulations of the operation and validation of the numerical results, a neural network was trained and combined with the genetic algorithm to obtain the optimum design parameters. The outcomes of this investigation have shown that these optimized process variables simultaneously resulted in the best values for both the objective functions, in comparison with all the conducted finite-element analyses.
- انتشار مقاله: 11-09-1396
- نویسندگان: Saeed Yaghoubi,Faramarz Fereshteh-saniee
- مشاهده
- جایگاه : پژوهشی
- مجله: International Journal of Advanced Design and Manufacturing Technology
- نوع مقاله: Journal Article
- کلمات کلیدی: 2024 Al Alloy,Damage Mechanism,Kintzel Damage Model,Periodic Loading
- چکیده:
- چکیده انگلیسی: Damage mechanics is one of the most important parts of mechanical engineering that determines the time life for different mechanical elements. The most various models that have been provided so far in damage mechanics, are related to ductile or brittle damage. Nowadays, the investigation of materials by ductile-brittle damage behavior has been considered by researchers. Kintzel quasi-brittle damage model is one of the best damage models in this field. Therefore, in this paper, due to the application of 2024 Al alloy in different industries especially aerospace and the ductile-brittle damage behavior of this alloy, the implementation of the Kintzel quasi-brittle damage model is presented. For this purpose, by writing an explicit user subroutine VUMAT in finite element software (ABAQUS), a test sample under periodic loading has been modeled. The results of this research showed that the complete failure occurs after the 12th cycle under a periodic loading. Also, 2024 Al alloy showed a good ultimate tensile strength (about 400 MPa) under periodic loading. The magnitude of ductile and brittle damage variables are 0.23 and 0.38, respectively.
- انتشار مقاله: 01-12-1397
- نویسندگان: Sadegh Ghorbanhosseini,Saeed Yaghoubi
- مشاهده
- جایگاه : پژوهشی
- مجله: Advances in Industrial Engineering
- نوع مقاله: Journal Article
- کلمات کلیدی: Genetic Algorithm,Simulated annealing algorithm,Location-routing problem,Simultaneous pickup and delivery,Two-echelon
- چکیده:
- چکیده انگلیسی: Integrated optimization approach in supply chain has become one of the most important and interesting subjects for researchers in recent years. In this paper, a mathematical model is presented for two-echelon location-routing problem with simultaneous pickup and delivery, so that a layer of facilities with the name of “middle warehouse” are located between main distribution centers and customers. Each customer has demands for commodity reception and delivery simultaneously. In this paper, first a two-echelon integer programming mathematical model, which central/middle storerooms capacities are considered limited, is presented. Then, using genetic and simulated annealing algorithms, a hybrid metaheuristic method is delivered for solving the model. Numerical results of solving sample instances in different sizes confirm the good performance of our approach.
- انتشار مقاله: 03-05-1394
- نویسندگان: MohammadReza Ghatreh Samani,Seyyed-Mahdi Hosseini-Motlagh,Saeed Yaghoubi,Abbas Jokar
- مشاهده
- جایگاه : پژوهشی
- مجله: Advances in Industrial Engineering
- نوع مقاله: Journal Article
- کلمات کلیدی: Backup facilities,Location-allocation of distribution systems,Mobile warehouse,Scenario-based stochastic programming
- چکیده:
- چکیده انگلیسی: In this paper, a facility location problem of distribution systems, as one of the important and strategic issues in supply chain management, has been studied in a three-level supply chain under a stochastic condition. For this purpose, a two-stage mathematic model has been proposed for the location-allocation problem of distribution systems with regard to backup facilities for disrupting warehouse storage facilities in the three-level supply chain that minimizes the sum of the costs. In the first stage, locating the mobile warehouse of distribution systems and transferring the products between manufactures and mobile warehouses have been decided and in the second stage, meeting customer demands with regard to disrupting mobile warehouses and backup facilities have been also decided. In addition, disruption in warehouses is considered as different scenarios for overcoming computational time in large dimensions. Moreover, a Lagrangian relaxation solution framework to reduce solution time is used. Finally, numerical examples are solved with GAMS software and then the objective function of the problem is compared with the objective function of a Lagrangian relaxation solution to show the effectiveness of the proposed model.
- انتشار مقاله: 23-06-1393
- نویسندگان: Saeed Yaghoubi,Jamal Nahofti Kohne,Amir Khosrojerdi,Ahmad Mohamadi
- مشاهده