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Dr. Zahra Esfandiari, Prof. Mahdi Bashiri, Prof. Reza Tavakkoli-Moghaddam,
Volume 0, Issue 0 (3-2020)
Abstract

One of the major risks that can affect supply chain design and management is the risk of facility disruption due to natural hazards, economic crises, terrorist attacks, etc. Static resiliency of the network is one of the features that is considered when designing networks to manage disruptions, which increases the network reliability. This feature refers to the ability of the network to maintain its operation and connection in the lack of some members of the chain. Facility hardening is one of the strategies used for this purpose. In this paper, different reliable capacitated fixed-charge location allocation models are developed for hedging network from failure. In these proposed models, hardening, resilience, and hardening and resilience abilities are considered respectively. These problems are formulated as a nonlinear programming models and their equivalent linear form are presented. The sensitivity analysis confirms that the proposed models construct more effective and reliable network comparing to the previous networks. A Lagrangian decomposition algorithm (LDA) is developed to solve the linear models. Computational results show that the LDA is efficient in computational time and quality of generated solutions for instances with different sizes. Moreover, the superiority of the proposed model is confirmed comparing to the classical model.
Mangesh Phate, Shraddha Toney, Vikas Phate,
Volume 0, Issue 0 (3-2020)
Abstract

In the present work, a model based on dimensional analysis (DA) coupled with the Taguchi method to analyze the impact of silicon carbide (SiC) has been presented. The wire cut electrical discharge machining (WEDM) performance of aluminium silicon carbide (AlSiC) metal matrix composite (MMC) has been critically examined. To formulate the DA based models, total 18 experiments were conducted using Taguchi’s L18 mixed plan of experimentation. The input data used in the DA models are a pulse on time, pulse off time, wire feed rate, % SiC, wire tension, flushing pressure etc. According to these process parameters, DA models for the surface roughness and the material removal rate was predicted. The formulated DA models have shown a strong correlation with the experimental data. The analysis of variance (ANOVA) has been used to find out the impact of individual parameters on response parameters.  
 
Elham Moazzam Jazi, Hadi Abdollahzadeh Sangroudi,
Volume 0, Issue 0 (3-2020)
Abstract

Biofuels production systems are identified as a potential solution in responding to the ever-increasing energy consumption demand. The complexity of conversion process and supply chain of these systems, however, can make the commercialization of biofuels less attractive, so designing and management of an efficient biofuel supply chain network can resolve this issue. Hence, this paper proposes a multi-period hybrid generation biomass-to-biofuel supply chain considering environmental, economic and technology considerations. The objective is to maximize the total profit that biofuel producers can make with practical constraints including the biomass supply, the capacity of facilities, storage, Greenhouse Gas (GHG) emissions and transportation with limited capacity. To highlight the applicability of the proposed model, it is applied to a biomass-derived liquid fuel supply system in the southern region of Iran. In the case study, wheat and wheat stem are simultaneously considered as the first- and second-generation of feedstocks for biodiesel production. Sensitivity analyses show that available biomasses can have a significant impact on the profitability of this supply chain. The obtained results demonstrate the efficiency and performance of the proposed model in biodiesel supply chain design.
Vahid Babaveisi, Farnaz Barzinpour, Ebrahim Teimoury,
Volume 0, Issue 0 (3-2020)
Abstract

In this paper, an inventory-routing problem for a network of appliance repair service is discussed including several repair depots and customers. The customer in this network makes a demand to have his/her faulty appliance repaired. Then, the repairman is assigned to the demand based on the skill needed for repairing of appliance differing for each one. The assigned repairman picks up the faulty appliance from the customer place using the vehicle for transferring faulty appliances to repair depot. The vehicle for picking up and delivering the appliances has a maximum capacity. Additionally, the repair depot needs spare parts to repair the faulty appliances that is supplied either by the supplier or lateral transshipment from the other depots. The capacitated vehicle inventory-routing problem with simultaneous pickup and delivery is NP-hard which needs special optimization procedure. Regarding the skill of repairman, it becomes more complex. Many solution approaches have been provided so far which have their pros and cons to deal with. In this study, an augmented angle-based sweep method is developed to cluster nodes for solving the problem. Finally, the heuristic is used in the main body of genetic algorithm with special representation.
Gh. Yari , M. D Jafari ,
Volume 17, Issue 4 (11-2006)
Abstract

Main result of this paper is to derive the exact analytical expressions of information and covariance matrix for multivariate Pareto, Burr and related distributions. These distributions arise as tractable parametric models in reliability, actuarial science, economics, finance and telecommunications. We showed that all the calculations can be obtained from one main moment multidimensional integral whose expression is obtained through some particular change of variables. Indeed, we consider that this calculus technique for that improper integral has its own importance.


 


A. Aghajani , V. Roomi ,
Volume 18, Issue 1 (1-2007)
Abstract

Abstract: This paper investigates the problem of whether all trajectories of the system and cross the vertical isocline, which is very important for the existence of periodic solutions and oscillation theory. Sufficient conditions are given for all trajectories to cross the vertical isocline.

 


Asghar Mohammad Moradi , Mahdi Akhtarkavan,
Volume 18, Issue 6 (7-2007)
Abstract

The present paper will investigate the specific elements of architectural design based on Islamic beliefs, by taking Iranian Architectural values and vernacular climate design methods into consideration. This research will assess the spirit of experimental elements, created by the inhabitants, according to recent scientific findings. The main concentration will be on the physical design of rural areas in hot, arid and sunny regions of Iran in order to have active and healthy environments and to emphasize on transferring all these sustainable values to the future.
Esmaeil Shieh, Ayyoob Sharifi,
Volume 18, Issue 6 (7-2007)
Abstract

  The study seeks to address the importance of urban stream ecosystems from the perspective of urban ecology, human health and social well-being in the context of urban planning. The case study area is Paveh stream in the City of Paveh. The data from the case study area were gathered from questionnaire, existing scientific and library studies and by conducting interviews with residents and authorities. Once the importance of the biodiversity of the stream had been studied based on the existing ecological data, the social importance of the stream and the linkages between human health, social well-being and the biodiversity of the stream ecosystem were addressed.

  Based on the results of the survey and other sources of information, it was discussed that urban stream ecosystems can be rich in biodiversity and function as ecological movement corridors for species .Urban stream corridors can thus be an important part of the urban green infrastructure .Also we can make the weather fine, extend green space, prepare peaceful environment for residents and bring the countryside effects of nature into cities through improvement of stream landscape.

Finally, regarding the finding of this study some suggestions and implications are mentioned to improve the quality of the stream.
E . Izadpanah , A . Akhavan Taheri , M . H Hekmat , S . Talebi,
Volume 19, Issue 7 (8-2008)
Abstract

In this paper, the combination of conduction with radiation into a semitransparent medium which includes absorption, emission and scattering has been investigated. In order to Study the conduction in medium, the Non-Fourier heat conduction has been applied. In this model there is a time delay between heat flux and temperature gradient. Also, in contrast with Fourier heat conduction, the speed of heat propagation is finite. The radiation transfer equation has been solved via approximate method. Also to solve the energy conservation equation and Non-Fourier heat conduction simultaneously, flux-splitting method has been applied. The results show that the transient temperature responses are oscillatory for Non-Fourier heat conduction. Also the Non-Fourier effect can be important when the thermal relaxation time of heat conduction is large. In the initial times, the difference of transient temperature responses between the Fourier and the Non-Fourier heat conduction is large under this condition. For the laser-flash measurement of thermal diffusivity in semitransparent materials, omitting the Non-Fourier effect can result in significant errors.

 

Keywords:
M. Habibnejad Korayem, A. Nakhaei ,
Volume 19, Issue 7 (8-2008)
Abstract

Mobile mechanical manipulators are one of the automation aspects which were revealed in last years of twentieth century. These machines assume the responsibility of human and gradually expand the domain of their activities in industry. This paper is a presentation of the Sweeper Robot designed in the Robotic Laboratory of Iran University of Science and Technology. The original design of this robot allowing to its gripper to constantly remain parallel to the ground is presented. The dynamic and kinematical models of the robot have been computed. A software was developed in MATLAB to validate the kinematical and dynamic models of the robot by comparison with the experimental results. Once the robot was built and its systematic odometric error estimated by experiment, a control scheme for linear motions was developed to deal with this error. The approach is based on the introduction of an initial rectifying offset motion before starting the linear motion. Eventually, classical line tracking and image processing algorithms were used to complete our robot and the efficiency of our design to achieve its mission in picking and placing different objects according to various algorithms.


, , ,
Volume 20, Issue 1 (5-2009)
Abstract

  The problem of lot sizing, sequencing and scheduling multiple products in flow line production systems has been studied by several authors. Almost all of the researches in this area assumed that setup times and costs are sequence –independent even though sequence dependent setups are common in practice. In this paper we present a new mixed integer non linear program (MINLP) and a heuristic method to solve the problem in sequence dependent case. Furthermore, a genetic algorithm has been developed which applies this constructive heuristic to generate initial population. These two proposed solution methods are compared on randomly generated problems. Computational results show a clear superiority of our proposed GA for majority of the test problems.


, , ,
Volume 20, Issue 1 (5-2009)
Abstract

Fuzzy Cognitive Maps (FCMs) have successfully been applied in numerous domains to show the relations between essential components in complex systems. In this paper, a novel learning method is proposed to construct FCMs based on historical data and by using meta-heuristic: Genetic Algorithm (GA), Simulated Annealing (SA), and Tabu Search (TS). Implementation of the proposed method has demonstrated via real data of a purchase system in order to simulate the system’s behavior.
Rasoul Haji, Mohammadmohsen Moarefdoost, Seyed Babak Ebrahimi,
Volume 21, Issue 4 (12-2010)
Abstract

  This paper aims to evaluate inventory cost of a Two-echelon serial supply chain system under vendor managed inventory program with stochastic demand, and examine the effect of environmental factors on the cost of overall system. For this purpose, we consider a two-echelon serial supply chain with a manufacturer and a retailer. Under Vendor managed inventory program, the decision on inventory levels are made by manufacturer centrally. In this paper, we assume that the manufacturer monitors inventory levels at the retailer location and replenishes retailer's stock under (r, n, q) policy moreover, the manufacturer follows make-to-order strategy in order to respond retailer's orders. In the other word, when the inventory position at the retailer reaches reorder point, r, the manufacturer initiates production of Q=nq units with finite production rate, p. The manufacturer replenishes the retailer's stock with replenishment frequency n, and the complete batch of q units to the retailer during the production time. We develop a renewal reward model for the case of Poisson demand, and drive the mathematical formula of the long run average total inventory cost of system under VMI. Then, by using Monte Carlo simulation, we examine the effect of environmental factors on the cost of overall system under VMI .


Arash Motaghedi-Larijani, Kamyar Sabri-Laghaie , Mahdi Heydari,
Volume 21, Issue 4 (12-2010)
Abstract

  In this paper flexible job-shop scheduling problem (FJSP) is studied in the case of optimizing different contradictory objectives consisting of: (1) minimizing makespan, (2) minimizing total workload, and (3) minimizing workload of the most loaded machine. As the problem belongs to the class of NP-Hard problems, a new hybrid genetic algorithm is proposed to obtain a large set of Pareto-optimal solutions in a reasonable run time. The algorithm utilizes from a local search heuristic for improving the chance of obtaining more number of global Pareto-optimal solutions. The solution method uses from a perturbed global criterion function for guiding the search direction of the hybrid algorithm. Computational experiences show that the hybrid algorithm has superior performance in contrast to previous studies .


Rassoul Noorossana, Abbas Saghaei , Mehdi Dorri,
Volume 21, Issue 4 (12-2010)
Abstract

  In an increasing number of practical situations, the quality of a process or product can be effectively characterized and summarized by a profile. A profile is usually a functional relationship between a response variable and one or more explanatory variables which can be modeled frequently using linear or nonlinear regression models. In this paper, we study the effect of non-normality on profile monitoring in Phase II when within or between autocorrelation is present. Different levels of autocorrelation and skewed and heavy-tailed symmetric non-normal distributions are used in our study to evaluate the performance of three existing monitoring schemes numerically. Simulation results indicate that the non-normality and autocorrelation can have a significant effect on the in-control performances of the considered schemes. Results also indicate that the out-of-control performances of the schemes are not very sensitive to low and moderate levels of autocorrelation in moderate and large shifts .


M. S Jabalameli, B. Bankian Tabrizi, M. Moshref Javadi ,
Volume 21, Issue 4 (12-2010)
Abstract

  The problem of locating distribution centers (DCs) is one of the most important issues in design of supply chain. In previous researches on this problem, each DC could supply products for all of the customers. But in many real word problems, DCs can only supply products for customers who are in a certain distance from the facility, coverage radius. Thus, in this paper a multi-objective integer linear programming (MOILP) model is proposed to locate DCs in a two-echelon distribution system. In this problem, customers who are in the coverage radius of the DCs can be supplied. Moreover, we suppose that the coverage radius of each DC can be controlled by decision maker and it is a function of the amount of money invested on the DC. Finally, a random generated problem is used to verify the model and the computational results are presented .


E. Teimoury, H. Ansari , M. Fathi ,
Volume 22, Issue 1 (3-2011)
Abstract

  The importance of reliable supply is increasing with supply chain network extension and just-in-time (JIT) production. Just in time implications motivate manufacturers towards single sourcing, which often involves problems with unreliable suppliers. If a single and reliable vendor is not available, manufacturer can split the order among the vendors in order to simultaneously decrease the supply chain uncertainty and increase supply reliability. In this paper we discuss with the aim of minimizing the shortage cost how we can split orders among suppliers with different lead times. The (s,S) policy is the basis of our inventory control system and for analyzing the system performance we use the fuzzy queuing methodology. After applying the model for the case study (SAPCO), the result of the developed model will be compared in the single and multiple cases and finally we will find that order splitting in optimized condition will conclude in the least supply risk and minimized shortage cost in comparison to other cases .


M. Yaghini, M. Momeni, M. Sarmadi ,
Volume 22, Issue 1 (3-2011)
Abstract

  The traveling salesman problem is a well-known and important combinatorial optimization problem. The goal of this problem is to find the shortest Hamiltonian path that visits each city in a given list exactly once and then returns to the starting city. In this paper, for the first time, the shortest Hamiltonian path is achieved for 1071 Iranian cities. For solving this large-scale problem, two hybrid efficient and effective metaheuristic algorithms are developed. The simulated annealing and ant colony optimization algorithms are combined with the local search methods. To evaluate the proposed algorithms, the standard problems with different sizes are used. The algorithms parameters are tuned by design of experiments approach and the most appropriate values for the parameters are adjusted. The performance of the proposed algorithms is analyzed by quality of solution and CPU time measures. The results show high efficiency and effectiveness of the proposed algorithms .


Mir. B. Aryanezhad, M.j. Tarokh, M.n. Mokhtarian, F. Zaheri,
Volume 22, Issue 1 (3-2011)
Abstract

  Multiple criteria decision making (MCDM) problem is one of the famous different kinds of decision making problems. In more cases in real situations, determining the exact values for MCDM problems is difficult or impossible. So, the values of alternatives with respect to the criteria or / and the values of criteria weights, are considered as fuzzy values (fuzzy numbers). In such conditions, the conventional crisp approaches for solving MCDM problems tend to be less effective for dealing with the imprecise or vagueness nature of the linguistic assessments. In this situation, the fuzzy MCDM methods are applied for solving MCDM problems. In this paper, we propose a fuzzy TOPSIS (for Order Preference by Similarity to Ideal Solution) method based on left and right scores for fuzzy MCDM problems. To show the applicability of the proposed method, two numerical examples are presented. As a result, our proposed method is precise, easy use and practical for solving MCDM problem with fuzzy data. Moreover, the proposed method considers the decision makers (DMs) preference in the decision making process. It seems that the proposed fuzzy TOPSIS method is flexible and easy to use and has a low computational volume .


Saeed Ramezani , Azizollah Memariani,
Volume 22, Issue 2 (6-2011)
Abstract

 

  Condition Monitoring,

  Oil Analysis, Wear Behavior,

  Fuzzy Rule Based System

 

Maintenance , as a support function, plays an important role in manufacturing companies and operational organizations. In this paper, fuzzy rules used to interpret linguistic variables for determination of priorities. Using this approach, such verbal expressions, which cannot be explicitly analyzed or statistically expressed, are herein quantified and used in decision making.

In this research, it is intended to justify the importance of historic data in oil analysis for fault detection. Initial rules derived by decision trees and visualization then these fault diagnosis rules corrected by experts. With the access to decent information sources, the wear behaviors of diesel engines are studied. Also, the relation between the final status of engine and selected features in oil analysis is analyzed. The dissertation and analysis of determining effective features in condition monitoring of equipments and their contribution, is the issue that has been studied through a Data Mining model.

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