Ali Ghorbanian | Tarbiat Modares University (original) (raw)

Papers by Ali Ghorbanian

Journal Européen des Systèmes Automatisés

Considering the importance of time in today's world and the rising traffic congestion in urba... more Considering the importance of time in today's world and the rising traffic congestion in urban areas, using methods to reduce wait times and air pollution can have a significant impact on promoting urban management. Given the uncertainty in the number of vehicles and the emission rate of vehicles, a complex T intersection with three traffic lights was simulated in this study. Three objective functions were defined for the mean of wait time, average queue length, and aggregate pollutant emission of the vehicles in queue. First, regression equations for each of the variables were obtained by a full factorial design and analysis of variance, and the optimal period for each traffic light was then computed with a utility function approach. Finally, the results were compared to the results obtained from the optimization of each response variable OptQuest for Arena software.

Many complex systems can be modeled as complex networks, so we can use network theory to study th... more Many complex systems can be modeled as complex networks, so we can use network theory to study this model. One important feature in networks is community structure, i.e. the organization of nodes in communities, with many edges joining nodes of the same community and comparatively few edges joining nodes of different communities. A large number of community detection algorithms have been proposed in the last decade. Many of these algorithms use modularity as function to optimize. The modularity has been exposed that have resolution limits and contains an intrinsic scale that depends on the total size of edges in the network. Modules smaller than this scale may not be detected even in the extreme case that they are complete graphs connected by single bridges. Recently a new quantitative measure has been proposed for evaluating the partition of a network into communities called modularity density. In this paper we propose a genetic algorithm to optimize this quantitative measure. We u...

Design of experiments Multi-objective optimization Today internet based technologies effect on al... more Design of experiments Multi-objective optimization Today internet based technologies effect on all aspects of our life rapidly. Undoubtedly, our hobbies get changed by technology like online games. Because of online games servers are expensive, determining optimal number of them in all around the world is became critical for game companies. On the other hand decreasing costs by reducing game servers result to servers overload therefore new users have to wait until free capacity will be available. It is worth noting that waiting users have extra costs like lost users for companies. In this paper we will provide a methodology in five following phases: mathematical modeling, collecting data and simulation, experimental design with reliability function approached in order to find out optimal answer of this problem. 1.

Determining the number of elements in each stage of a series – parallel system is considered as a... more Determining the number of elements in each stage of a series – parallel system is considered as an important aspect in the reliability literature. Several methods have been proposed for solving this problem in recent years. But most of them are merely explore the maximization of system reliability and ignore the entropy as an important physical concept which is indicates the amount of disturbances in the system. In this paper, a robust optimization approach based on design of experiment (DOE) for the series-parallel system of LCD unit display with considering the constraint of cost has been proposed. The proposed not only optimize the LCD screen entropy and reliability, but also minimize the impacts of uncontrollable variables (noise factors) on the discussed objectives. 1.

World Applied Programming, 2015

Abstract: Determining the number of elements in each stage of a series parallel system is conside... more Abstract: Determining the number of elements in each stage of a series parallel system is considered as an important aspect in the reliability literature. Several methods have been proposed for solving this problem in recent years. But most of them are merely explore the maximization of system reliability and ignore the entropy as an important physical concept which is indicates the amount of disturbances in the system. In this paper, a robust optimization approach based on design of experiment (DOE) for the series-parallel system of LCD unit display with considering the constraint of cost has been proposed. The proposed not only optimize the LCD screen entropy and reliability, but also minimize the impacts of uncontrollable variables (noise factors) on the discussed objectives.

Nowadays, networks are widely used to show the structure and type of relationship in various fiel... more Nowadays, networks are widely used to show the structure and type of relationship in various fields of science including social sciences, engineering, and social network. Investigating the structure of these networks has always been of interest to many people. To this end, the present study tries to identify these networks as interconnected communities, while each community might have unique properties. In this regard various methods and algorithms with different evaluation criteria are used, with the evolutionary algorithm having the highest share. The present research attempts to introduce a relatively efficient method for community detection through introduction of a new evaluation criterion based on the modularity density and giving weight to the relationships between nodes in the unweighted networks. For this purpose, at first we propose a new modularity based on difference of weight of nodes in a same community with other community also for this we propose a method for calcula...

International Journal of Economy, Management and Social Sciences, 2015

Abstract: Many complex systems can be modeled as complex networks, so we can use network theory t... more Abstract: Many complex systems can be modeled as complex networks, so we can use network theory to study this models. One important feature in networks is community structure, i.e. the organization of nodes in communities, with many edges joining nodes of the same community and comparatively few edges joining nodes of different communities. A large number of community detection algorithms have been proposed in the last decade. Many of these algorithms use modularity as function to optimize. The modularity has been exposed that have resolution limits and contains an intrinsic scale that depends on the total size of edges in the network. Modules smaller than this scale may not be detected even in the extreme case that they are complete graphs connected by single bridges. Recently a new quantitative measure has been proposed for evaluating the partition of a network into communities called modularity density. In this paper we propose a genetic algorithm to optimize this quantitative me...

In this study, we first examined the research and studies in the field of analysis and modeling o... more In this study, we first examined the research and studies in the field of analysis and modeling of business processes dealt, Then a methodology for analyzing a business process based on the organizational ontology and process simulation have provided and For this purpose, a variety of organizational ontology of process analysis have studied, Then by identify existing gaps in the ontology, a Ontology-based enterprise knowledge management in organizations have developed and based on this Ontology, we provide a list for four dimensions of manpower, organization, skills and knowledge to identify the shortcomings of our procurement process. In fact, the proposed methodology aims to be a business process from both the quantitative and qualitative simulation tool by using of Ontology and organizational framework for the simultaneous quantitative and qualitative analysis provide a process. In this case study, we have used the sale of a steel plant, The results of simulation according to the...

Abstract: Today internet based technologies effect on all aspects of our life rapidly. Undoubtedl... more Abstract: Today internet based technologies effect on all aspects of our life rapidly. Undoubtedly, our hobbies get changed by technology like online games. Because of online games servers are expensive, determining optimal number of them in all around the world is became critical for game companies. On the other hand decreasing costs by reducing game servers result to servers overload therefore new users have to wait until free capacity will be available. It is worth noting that waiting users have extra costs like lost users for companies. In this paper we will provide a methodology in five following phases: mathematical modeling, collecting data and simulation, experimental design with reliability function approached in order to find out optimal answer of this problem.

International Journal of Applied Management Science

Revenue management (RM) is a subfield of operations research with the aim to maximise the revenue... more Revenue management (RM) is a subfield of operations research with the aim to maximise the revenues acquired by selling perishable products/services. Due to the substantial growth in air cargo industry over the past few years, sophisticated techniques are needed to maximise revenue. In this paper, airline cargo capacity allocation problem in two cases, including cancellation possibility and impossibility have been investigated. Two capacity dimensions of the problem, volume and weight, is complicated the decision making about request acceptance policy. For the formulation of two problems, dynamic programming technique has been used. Since dynamic programming suffers from much memory consumption for large size problems, three heuristics including deterministic integer linear programming (DILP), bid price (BP) and dynamic programming decomposition (DPD) has been proposed for problems solving. Results of simulation showed that BP and DILP have the better performance comparing to other approaches. In addition, comparison of two problem's optimum values indicated that considering cancellation increase total revenue more than 10%.

International Journal of System Assurance Engineering and Management

Abstract The uncertainties existing in today’s manufacturing environment tends researchers to use... more Abstract The uncertainties existing in today’s manufacturing environment tends researchers to use statistical and simulation approach to address such stochastic problems. The supplier selection problem has attracted growing interest. One of the crucial issues in supplier selection is product outsourcing. The outsourcing improved the service price by decreasing that, also it reduced the waiting time and increased the customer satisfaction. Furthermore, it improved the company’s core competence. In supplier selection problem, some criteria are effective such as: cost, delivery time, quality. During recent years, various approaches are proposed for supplier selection problem. But in one hand, most of them have considered only single criteria, and on the other hand, some stochastic parameters are assumed to be deterministic. In this study, a statistical method based on design of experiment (DOE) and simulation is presented that minimizes cost and lead times while maximizes quality in the existence of discount. Furthermore, model parameters such as demand, lead time, and rejected products percentage are assumed as stochastic parameters. Finally, the model has been solved using weighted objective method and compromise programming and then the results have been analyzed.

The European Physical Journal Plus

Abstract.In this paper, the physical optimization of a wavy porous cavity is evaluated while it i... more Abstract.In this paper, the physical optimization of a wavy porous cavity is evaluated while it is filled with nanofluids and under the solar radiation heat flux by using numerical and statistical methods. The effect of four parameters is discussed on the Nusselt number: Wavy amplitude ( AmA_{m}AmAm, solar heat flux, Darcy number and Rayleigh number. To find the effect and interaction of these parameters on the heat transfer, a Box-Behnken design (BBD) is used and analysis is performed on the 27 experiments proposed by BBD. Analysis of variance (ANOVA) of the results revealed that solar heat flux and wave amplitude have a strong effect on the Nusselt number compared to Darcy and Rayleigh numbers. Finally, the response surface methodology (RSM) was applied to find the optimized case while its error was 0.002% in predicting the Nusselt number for the optimized case which confirms the high accuracy of results.

Scientia Iranica

In this study, a multi-state degraded system is studied, where status of system is continuously d... more In this study, a multi-state degraded system is studied, where status of system is continuously degrading over time. As time progresses, system may either deteriorate gradually and go to lower performance state, or it may fail suddenly. If the system fails, some repairs are carried out to restore the system to the previous state. When the inspections reveal that the system has reached its last acceptable state, a PM is carried out to restore the system to the higher performance states. The goal is to nd the optimal PM level, so that the mean availability of the system is maximized and the total cost of the system is minimized. In this regard, Markov process is employed to represent di erent states of system. An integrated optimization approach is also suggested based on the desirability function of statistical approach. The suggested aggregation method is robust to the potential dependency between the total cost and the mean availability. It also ensures that both objective functions fall in decision-maker's acceptable region. In order to show the e ciency of the proposed approach, a numerical example is presented and analyzed.

International Journal of Data Analysis Techniques and Strategies

Redundancy allocation problem includes enhancing system reliability within parallel arrangement o... more Redundancy allocation problem includes enhancing system reliability within parallel arrangement of each subsystem component. During recent years, various approaches have been proposed to solve this problem, although most of them only pursue the maximisation of the system reliability. Meanwhile, increasing the number of identical components in each subsystem leads to higher cost of the system. Therefore, this paper presents an approach based on design of experiments (DOE) and data envelopment analysis (DEA) in order to determine the number of redundant component by considering both reliability and cost of the system. Since most of continuous production systems has high setup cost, the proposed approach uses the opportunistic maintenance policy for application of most restorative operations in each system halt.

International Journal of Applied Management Science, 2016

The optimal allocation of seat inventory is a well-known problem of airline revenue management in... more The optimal allocation of seat inventory is a well-known problem of airline revenue management in the airline industry. It is usually carried out among fare classes with a known demand distribution for each class with the aim at increasing the efficiency of revenue systems and enhancing customer satisfaction. Furthermore, an important assumption is the issue of cancellation which is very common in the field of airlines. So to avoid having unused seat in a flight, overbooking technique is used. During last years, different approaches have been proposed for addressing this problem, but most of them only considered revenue to be maximised. In this paper, an optimisation approach based on Taguchi design of experiment and COPRAS decision-making method is proposed. The suggested method not only maximises total revenue and customer satisfaction simultaneously, but also mitigates the effects of nuisance factors on system by minimising the variance of two objectives. Experimental results on a standard example show the effectiveness of the proposed method.

Asian Journal of Research in Business Economics and Management, 2015

The main purpose of this paper is to propose a suitable model for determining the appropriate mar... more The main purpose of this paper is to propose a suitable model for determining the appropriate marketing strategy based on corporate resources and capabilities. In this regard, a three-step multiple criteria decision making framework is developed to determine the most appropriate marketing strategy in an efficient manner. In this framework, first the corporate criteria for marketing strategy selection are determined through a comprehensive survey of the related literature and corporate's expert judgments. Then fuzzy AHP method is applied to calculate the relative importance of these criteria. Finally VIKOR method is used for the purpose of ranking strategies based on the selection criteria. The feasibility of the proposed model is demonstrated by applying the framework in an Iranian company which is working in the field of food industry. Moreover, this framework can be easily understood and applied by marketing strategists in other fields of industry.

Applied Mathematical Modelling, 2013

The aim of this paper is to solve a supplier selection problem under multi-price level and multi-... more The aim of this paper is to solve a supplier selection problem under multi-price level and multi-product using interactive two-phase fuzzy multi-objective linear programming (FMOLP) model. The proposed model attempts to simultaneously minimize total purchasing and ordering costs, a number of defective units, and late delivered units ordered from suppliers. The piecewise linear membership functions are applied to represent the decision maker's fuzzy goals for the supplier selection and order allocation problem, and can be resulted in more flexibility via an interactive decision-making process. To demonstrate effectiveness of the proposed model, results of applying the proposed model are shown by a numerical example. The analytical results show that the proposed approach is effective in uncertain environments and provide a reliable decision tool for integrated multiobjective supplier selection problems.

International Journal of Applied Decision Sciences, 2015

Supplier evaluation and selection is a vital problem in supply chain management of which the two ... more Supplier evaluation and selection is a vital problem in supply chain management of which the two most important factors are procurement cost and products quality level. Researchers have investigated many aspects of this problem so far. These factors, as delivery time and customer behaviour against product quality, are uncertain. Nevertheless, for the purpose of simple application, they are usually considered deterministic. To have more accurate modelling of the real world, it is necessary to consider these uncertain factors in models. Making sure that chain profit and product quality satisfy the decision maker, this paper develops a robust approach based on design of experiments and simulation for selection of suppliers in a closed loop supply chain, product quality. By implementing signal-to-noise ratio, variances of cost and product quality, as secondary objectives in optimisation process, are minimised to reduce the effect of noise factors on the objective functions under consideration.