نشریه بین المللی مهندسی صنایع و مدیریت تولید
سال بیست و دوم شماره 2 (تابستان 1390)

Being one of the major research fields in the robotics discipline, the robot motion planning problem deals with finding an obstacle-free start-to-goal path for a robot navigating among workspace obstacles. Such a problem is also encountered in path planning of intelligent vehicles and Automatic Guided Vehicles (AGVs). Traditional (exact) algorithms have failed to solve the problem effectively since it is proven that the complexity of the problem is NP-hard. Consequently, several heuristic algorithms have been developed for solving the problem, among which the Genetic Algorithms (GA) evolutionary approach has been increasingly utilized. In this paper, a new GAbased method has been developed to improve the drawbacks of current GA methods regarding fixed chromosome string size and limitations in the crossover and mutation operators. In this method, first the workspace is tessellated via the Delaunay triangulation, and a set of paths are created using the powerful Rapidly-exploring Random Trees (RRT) and smoothed. As a result, a population of variable-length chromosomes is obtained, which is a novelty in the field. Next, these solutions are improved further by using new selection, crossover and mutation operators, in which the triangulation plays a pivotal role. Extensive Simulations of the algorithm showed that the obtained path lengths are averagely 25% shorter than those found by the pure RRT method.

One of the main elements of each supply chain is production. Production planning in multi-products process industries in which products are subjected to the complicated operational constraints is a very hard work because production of computed optimal volume should be compatible with operation scheduling constraints of production system. Thus, integration idea has been proposed for required decisions of these two problems. The main dilemma in integration is how to make relation between production planning problem with middle term time interval and production scheduling problem with short term time interval. In this paper, we formulate and integrate production planning and operation scheduling problems in continuous process industries with multi products and capability of saving partial products in short and long terms time intervals. In continue, a heuristics solution approach has been proposed and its performance has been evaluated using a practical case study..

Accession to WTO (World Trade Organization) is the most important facets of globalization, that causes free trade. Although this way empowers economical fields but would make vast bankrupts and unemployment, so the main strategy is defending from priorities in accession. Iran membership was accepted by WTO in 2005 and it is preparing action plans based on production priorities. Machinery industries with the most value added has main role in industrial priorities so the main contribution of this research is determining priorities in machinery industry. For achieving this goal after literature review we ran a Topsis model by expert opinions. The other contribution of this research is utilization of economical, social and environmental factors that make our analysis more applicable than former models (like Porter). With comparison by AHP results, finallyfour clusters appeared: leader, developing, reviewing and weak production groups that makes a regular base for accession plan to WTO.

In this paper a new nonlinear integer programming model is presented for dynamic cell formation problem (DCF) in cellular manufacturing system (CMS). idea “higher material flow in shorter distance” for formation of cells is introduced. Since the linearized model is NP-hard, a novel approach called local search embeded branch and cut (LSEBC) is introduced. Computational results show the efficiency of the LSEBC in comparison with standard comparable methods.

Allocating equipments and facilities to the different operations, has been always an important problem for harbor managers. In this paper we try to present an effective methodology to allocate the equipments and facilities to the harbors. The proposed methodology uses simulation and multiple criteria decision making (MCDM) tools to analyze the system. Encountering such problem (selecting the alternatives to improve the performance of harbor) needs to be evaluated from different dimensions not one dimension. So we used the MCDM for this purpose. To evaluate effectiveness of the methodology, the mentioned methodology was implemented in shahid rajaee port. Considering the available constraints of the harbor to increase the facilities and equipments, and also considering different decision making criteria, the best alternative to improve the system was selected.

This study has proposed a new procedure, based on expanded RFM model, determining weight of parameters with pair-wise comparison matrix, clustering the products with K-optimum according to Davies- Bouldin Index, and then classifying customer product loyalty under B2B concept. It is necessary for firms to understand the customers and predict their needs for more success in business. The developed methodology has been implemented in SAPCO Co. The result shows a tremendous capability to the firm to assess the customer loyalty in marketing strategy designed by this company in comparing with random selection commonly used by most companies in Iran.

One of the assumptions in Econoic Production Quantity is that there is no imperfect production. Also the effect of inflation and time value of money is not considered with this model. But the studies show that the consideration of imperfect products in lot sizing or inflation and time value of money is varying the optimal lot size, therefore consideration of these two factors in lot sizing is essential. This paper studies the effect of inflation and time value of money on the EPQ model with rework. Since the total cost relation involves a complicated exponential function, evaluating the optimal point is not a trivial task. The effect of inflation and time value of money was investigated under given sets of values of inflation and discount rates. Computational results indicate that this effect on the model is very important.

This paper describes Risk Based Inspection (RBI) methodology which is constructed in one of the units of Tehran Oil Refinery, (ISOMAX unit). The result of RBI Execution is a risk matrix which is constructed with Probability of Failure and Consequence of Failure. To define risk, probability of failure and consequence of failure and active damage mechanism were recognized. Riskwise software was assisted for implementing RBI. All equipment categorized into 3 main risk area based on the RBI results which were high risk, medium risk and low risk. High risk area is separated to Toxic and Non-Toxic area. As a result 4 risk area was considered. In addition an application of the Analytical Hierarchy Process (AHP) to select the most practicable maintenance strategy for equipment which is located in each risk area is described. To arrange the hierarchic structure & evaluation, four main criteria were defined (safety, cost, value added, feasibility) for pairwise judgments. Four possible alternatives are considered to complete the model, preventive, corrective, condition based and reliable centered maintenance.

During recent years, tendencies towards Enterprise Resource Planning (ERP) systems are growing both in service and manufacturing organizations. Service organizations have invested considerable resources in the implementation of ERP systems forintegrating information, improving services quality and more customers satisfaction, even using solutions initially targeted for manufacturing companies. service operations, however build up a suitable potential in using ERP.Healthcare is one of the most important fields in services. Implementation of ERP solution in the healthcare havent been done yet in Iran, Although This type of organizations should have integrated their information and make them available in real-time.The aim of this thesis is to study the way of ERP Implementation for Integrating Information, Reducing high ERP Implementation costs and Identifying risk factors in healthcare centers. This research has focused on Modeling of ERP implementation. In that purpose, this model is helpful for managers to make a decision about implementingERP in their organizations and diagnose risks for better control.