Seved Mohammad A'arabi; Rahim Abedi
Volume 8, Issue 19 , December 2010, , Pages 239-277
Abstract
This paper aims at studying the strategic alignment among business strategy, financial strategy, investment strategy, financing strategy, dividend strategy, and working capital strategy based on a comprehensive model (based on strategic reference points - SRP's). The comprehensive model is based on process ...
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This paper aims at studying the strategic alignment among business strategy, financial strategy, investment strategy, financing strategy, dividend strategy, and working capital strategy based on a comprehensive model (based on strategic reference points - SRP's). The comprehensive model is based on process view in strategic management were implementation is a function of formulation (focus internal or external - SRP1) and control (low or high - SRP2). In this paper at first we identify typologies of business, financial and subsystem strategies based on SRP's, and then study the relationship among these strategies. Survey research strategy used in this study. 273 Tehran Exchange Production Companies were selected for statistical population and 67 Companies included in statistical population have collaborated in this research. Types of business, financial and subsystem strategies calculated for 67 Companies in 2008. Measurement tools were questionnaire, interviewing and financial statements analyses. Descriptive statistical methods are used for data gathering. Analytical statistical methods, parametric and nonparametric were used for data analyses. The results show that, external (vertical) alignment between financial strategy and business strategy, internal (vertical) alignment between financial and subsystem or functional strategies, internal (horizontal) alignment between financial subsystem strategies and external (vertical) alignment between financial subsystem strategies and business strategy and interaction among these strategies affect the performance (ROA). The results reveal that, those companies with higher rate of alignment enjoy better performance (ROA) than those with average or lower alignment.
Maghsoud Amiri; Sara Hatami; Seyed Mostafa Moosavi
Volume 5, Issue 14 , December 2006, , Pages 251-273
Abstract
In this paper we try to determine optimal combination of effective factors to produce cattle feed. Cattle feed has direct relation with cattle health, this research is done on real case study, therefore the gained results could be too important. Both response surface methodology and design of experiments ...
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In this paper we try to determine optimal combination of effective factors to produce cattle feed. Cattle feed has direct relation with cattle health, this research is done on real case study, therefore the gained results could be too important. Both response surface methodology and design of experiments are used for modeling and improving cattle feed production process which has more than one effective factor. After effective factors identification, designing of experiments will be done by central composite design. Interference factors, effective and independent parameters are inspected by forward method and finally a model is obtained by independent parameters. Because of continuous space of the problem and nonlinear objective functions a metaheuristics named "genetic annealing" is used to solve the problem. Proposed algorithm searched the solution space parallel. Another algorithm, simulated annealing is also proposed to evaluate the performances of two algorithms by improvement percent between initial and final result.
Mohammad Tasharofi
Volume 8, Issue 19 , December 2010, , Pages 279-294
Abstract
In this paper the budgeting procedures of a hypothetical bank to enter market and investing activities have been studied on the basis of the three factors; inflation rate, liquidity rate and GDP (Growth Domestic Products) employing General Linear Model. Related information was collected randomly from ...
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In this paper the budgeting procedures of a hypothetical bank to enter market and investing activities have been studied on the basis of the three factors; inflation rate, liquidity rate and GDP (Growth Domestic Products) employing General Linear Model. Related information was collected randomly from the year 2001 to 2007, and then analyzed statistically by the software Minitab version 15 and SPSS version 11.The result of the research showed that the inflation rate and liquidity grown had noticeable impact on GDP so the analysis proved a correlation coefficient relation between the variables with a range of 96 per cent. According to the analysis on the basis of a linear regression method in one hand and the variance obtained from the GLM process, some 83 per cent of correlation coefficient could be witnessed between Liquidity and inflation growth; while a 75 per cent of meaningful correlation coefficient can be traced in the effect of inflation rate on liquidity.
Adel Azar; Meisam Shahbazi; Ali Amiri
Abstract
The turbulent and dynamic environment of today's business world has become increasingly challenging for organizations operating in different business areas. In such a situation, in order to get rid of these conditions, moving forward and towards the perspective of the new horizons of prosperity and survival ...
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The turbulent and dynamic environment of today's business world has become increasingly challenging for organizations operating in different business areas. In such a situation, in order to get rid of these conditions, moving forward and towards the perspective of the new horizons of prosperity and survival is the dream of many of them. In the meantime, according to the specific circumstances and requirements that govern each institution or organization, and in order to achieve their desired productivity, they use certain strategies and programs that outsourcing is one of these strategies. Today, organizations are outsourcing to boost competitive ability and profit and focus on their competitive edge.In this research, a mathematical programming approach is proposed to optimize the issue of outsourcing in the supply chain. In this approach, at first the mathematical model of the problem showed and then in order to solve the problem of the theory of Markov chains described. The objective function of the problem involves minimizing the cost of purchasing, outsourcing and lost demand. In order to solve the problem, three genetic metamorphic algorithms, gray wolves and ant lion have been used. After examining the numerical expressions, Gray wolf's algorithm has the highest level of performance. In order to expand the applied dimensions of research in real-world conditions, a company (MPEICO) that manufactures insulators is considered as the case study
Mehdi Seifbarghy; Maryam Mohajeri
Abstract
This paper investigates a joint economic lot sizing model for a two echelon supply chain consisting of a single-vendor and multiple buyers. Recent studies have focused on the problem with equal batch sizes while this study proposed a mixed integer nonlinear programming model considering unequal batch ...
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This paper investigates a joint economic lot sizing model for a two echelon supply chain consisting of a single-vendor and multiple buyers. Recent studies have focused on the problem with equal batch sizes while this study proposed a mixed integer nonlinear programming model considering unequal batch sizes and shortage to minimize supply chain total cost. A heuristic procedure is proposed to find the solution and finally we show that unequal batch sizes delivers a more cost efficient solution.
supply chain management
Maedeh Fasihi; Seyed Esmaeil Najafi; Reza Tavakkoli-Moghaddam; Mostafa Hahiaghaei-Keshteli
Abstract
The supply chain management is an important factor in current competitive market. In recent years, the shortage of resources for answering an increasing food demand has increased researchers’ attention to the food supply chain. Given the importance of fish in the Household Food Basket, the development ...
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The supply chain management is an important factor in current competitive market. In recent years, the shortage of resources for answering an increasing food demand has increased researchers’ attention to the food supply chain. Given the importance of fish in the Household Food Basket, the development of aquaculture and recycling of returned goods in reverse logistics would significantly help with preserving water resources, as well as sustainable development. Therefore, government agencies and aquaculture industry beneficiaries are interested in reverse logistics. This study is focused on the optimization of a closed-loop supply chain of fish. To this end, a new bi-objective mathematical model is proposed that both minimizes total costs and maximizes fulfilling customers demand in uncertainty situation. Several well-known multi-objective meta-heuristic algorithms and a proposed hybrid meta-heuristic algorithm are applied to identify Pareto solutions. The solutions are then compared in terms of performance metrics. Also, the epsilon-constraint method and sensitivity analysis are used to validate the algorithms and evaluate the performance of the model. Lastly, the VIKOR method is used to select the superior method. To demonstrate the capability of the proposed model, a closed-loop supply chain of trout in northern Iran is investigated as a case study. The results show that the developed model could be effective in reducing the costs and increasing customer satisfaction.
Javad Behnamian; Amir Afsar
Abstract
In general, numerous studies have paid a special attention to machine planning, job allocating and job sequencing in scheduling problems to optimize makespan. Due to the relation among economy, energy and environmental concerns, energy use is one of the most important issues in different systems planning. ...
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In general, numerous studies have paid a special attention to machine planning, job allocating and job sequencing in scheduling problems to optimize makespan. Due to the relation among economy, energy and environmental concerns, energy use is one of the most important issues in different systems planning. In this paper, a scheduling of heterogeneous parallel machines is studied, in which the job process speed on every machine is settable. Since there is a direct link between used energy of machines and process speed, the purpose of the paper is to minimize total used energy and tardiness-related costs in delivering customers' demand. In order to optimizing the problem, two meta-heuristic algorithms, Memetic algorithm and Genetic algorithm, are developed, finally the results of both algorithms are analyzed and then compared to each other as well as to the results of the GAMS optimization software.
Shamsoldin Hosseini; Parham Azimi; Mani Sharifi; Mostafa Zandieh
Abstract
The aim of dynamic facility layout problem is to find the best layout for facilities at a multi period planning horizon so that the total cost of material handling and relocating the facilities is minimized. This paper developed a bi-objective mathematical model which is able to simultaneously minimize ...
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The aim of dynamic facility layout problem is to find the best layout for facilities at a multi period planning horizon so that the total cost of material handling and relocating the facilities is minimized. This paper developed a bi-objective mathematical model which is able to simultaneously minimize the material handling costs between facilities and the cost of rearrangement facilities and material handling time. Due to probabilistic characteristic of the transporters, such as the time of handling operation and existence of the failure, calculating the time required to carry the material using analytical relationships is impossible.Therefore, this paper uses the simulation approach and artificial neural networks. In this approach, a lot of scenarios are generated by combining of various levels of variables. Each scenario shows the location of the facilities and how transportation operations in each period is performed. Then each of these scenarios is implemented through computer simulation and simulation results are considered as the response variable. Finally, using input and response variable, an artificial neural network is trained to accurately estimate the time of carrying out the transportation operations. Given that the above problem is a NP-hard; this paper proposes a new meta-heuristic algorithm to optimize the problem and compares the performance of the proposed algorithm with existing algorithms in literature.
supply chain management
mohammadreza monjazeb; Mohammadkazem Sayadi; Mohammadjavad Farsayad
Abstract
Nowadays with increasing environmental pollution government's attention to the concept of the green supply chain has increased. The green supply chain produces a green product that is highly environmentally friendly. The purpose is to examine the impact of government intervention on competition between ...
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Nowadays with increasing environmental pollution government's attention to the concept of the green supply chain has increased. The green supply chain produces a green product that is highly environmentally friendly. The purpose is to examine the impact of government intervention on competition between chains, the environment and social welfare. This article presents three different models. In the first model the two green and non-green supply chains are competing with each other and the government is not present. In the second model, the government creates a culture to use the green supply chain and in the third model, is taxing the non-green supply chain. The objective of government is social welfare. In both models of government intervention, the game is in the form of a Stackelberg. Backward analysis method is used to solve the model. This method is a backward inference process in problems with limited steps, with the aim of obtaining optimal action in each step. MATLAB and Maple software are used for mathematical calculations and obtaining decision variables. The results show that if the government intervenes in a cultural way, environmental damage will decrease. Another result is that the conditions for increasing social welfare in the state of culture are determined. It is also possible for the green supply chain to increase its price if certain relationships are established between the parameters. In the tax collection model, if the government aims to maximize social welfare, social welfare will increase under any circumstances compared to the absence of the government.
Laya Olfat; Maghsood Amiri; Iman Raeesi Vanani; Mansour Esmaeilzadeh
Abstract
Today, it is difficult for organizations to survive without improving supplier performance and supplier relationships or gain competitive advantage. Therefore, suppliers must be managed and developed to meet the needs of the producer company. On the other hand, the supplier's development requires the ...
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Today, it is difficult for organizations to survive without improving supplier performance and supplier relationships or gain competitive advantage. Therefore, suppliers must be managed and developed to meet the needs of the producer company. On the other hand, the supplier's development requires the introduction of precise and comprehensive criteria. The aim of this paper is to identify the dimensions and categories of supplier development based on the criteria related to it, using the Meta-synthesis method. For this purpose, first we selected 102 studies from 136 studies, coding their texts with Atlas TI software, 23 concepts were identified for the criteria. Subsequently, through the analysis of literature, the identified concepts were classified into four tangible, intangible, environmental, and external dimensions and internal dimensions. To verify validity, triangulation of data, sources and researcher has been used. The content validity ratio and content validity index were calculated by a survey of automobile industry experts, four of the criteria were directly eliminated, and modifications and modifications were made on the criteria, and finally, 17 criteria for the development of suppliers in the automotive industry were finalized. The amount of Kappa coefficient obtained shows the reliability of the identified criteria. Finally, a two-dimensional model is proposed for the supplier-development criteria. Due to the lack of categorization of the criteria related to the supplier's development in previous studies, and in particular in domestic research, the identified criteria and their categorization can be useful for researchers in this field.
supply chain management
Akbar Rahimi; Alireza Boshehri; Arash Jafarian
Abstract
The oppressive sanctions of the superpowers in the supply of our country's military equipment, as well as the use of a significant number of helicopters with military and civilian applications (including transportation, rescue, agriculture, fire, crisis management, etc.), in the country, The importance ...
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The oppressive sanctions of the superpowers in the supply of our country's military equipment, as well as the use of a significant number of helicopters with military and civilian applications (including transportation, rescue, agriculture, fire, crisis management, etc.), in the country, The importance of Iran Helicopter Support and Renovation Company (Panha) has doubled and the functional diversity of these helicopters has made it necessary for the company to move towards design and construction. Given the company's mission and existing constraints, including sanctions, effective supply chain management is a key factor in its success. Disruptions as a result of unexpected events are an integral part of the company's supply chain, and applying the supply chain resilience approach to deal with these unexpected events, rapid recovery and return to normal (before the event), as the only A company providing support and modernization services for helicopters in Iran is essential.The purpose of this research is to develop a supply chain resilience model for Panha Company. First, the supply chain resilience practices are identified, then, according to the necessity of the applicability of the final model, practices is categorized in the form of a two-dimensional matrix of importance - feasibility. Also, using fuzzy Delphi method, the most important practices and performance measures related to Penha Company were extracted. Finally, using interpretive structural modeling, a model is presented that shows the relationships between important and feasible practices of the company's supply chain resilience.
Mohsen Tabatabaei; Abbas Afrazeh; Abbas Seifi
Abstract
This paper aims to propose a knowledge sharing optimization model based on the game theory that optimizes both employer and employee(s) decisions simultaneously. This model is a bi-level programming model. The upper-level problem includes employer decision about the reward, and the lower-level problem ...
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This paper aims to propose a knowledge sharing optimization model based on the game theory that optimizes both employer and employee(s) decisions simultaneously. This model is a bi-level programming model. The upper-level problem includes employer decision about the reward, and the lower-level problem contains employee(s) decisions about time and effort allocation to knowledge sharing activity. Mathematical formulation of the model designed based on previous literature and in the framework of Motivation-Opportunity-Ability. The proposed bi-level programming model provides a foundation to investigate more different parameters comparing with previous models introduced in the literature. This model considers opportunity and ability factors in addition to the motivation. Also, payoff functions in this model are non-linear and therefore is more consistent with real cases relative to previous linear models. Additionally, this model analysis the effects of available time as a key factor. The bi-level model coded in GAMS using EMP syntax and solved for a set of randomly generated data using BARON algorithm. Results show that the increase of applicability of codified knowledge and impact coefficient of social comparison could improve organizational performance and also save the cost of reward system. Therefore, neglecting these two parameters in designing a reward system could lead to non-optimized decision making. This research provides a basis to consider more parameters simultaneously and help to improve organizational decisions. However, based on the results, BARON algorithm is not efficient to solve big problems, so developing a more efficient algorithm is needed
alireza alinezhad; Abolfazl kazemi; Marzieh Karimi
Abstract
Location, routing and allocation decisions in supply chain management philosophy is undoubtedly one of the most important issues have very effect on the supply chain cost reduction and customer satisfaction. This paper presents an integrated approach to the distribution network. The objective functions ...
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Location, routing and allocation decisions in supply chain management philosophy is undoubtedly one of the most important issues have very effect on the supply chain cost reduction and customer satisfaction. This paper presents an integrated approach to the distribution network. The objective functions of the proposed mathematical model consist of minimizing the total costs associated with transportation and warehouse rental costs and also minimize the risk of the system. The model has high computational complexity and the exact method of solving it is not possible in a reasonable time. To solve the proposed model a multi-objective meta-heuristic algorithm which, known as the objective harmony search algorithm is presented. To demonstrate the effectiveness and efficiency of the proposed algorithm in solving the model, algorithm parameters are adjusted in the best possible rates using the Taguchi method. Then a random sample of the issues generated and the performance of the proposed algorithm comparing with NSGA-ǁ and NRGA are evaluated
production and operations management
yousef shamsi; houshang ta; soleiman Iranzadeh
Abstract
The purpose of this article is to develop a model of manufacturing flexibility in the food industry. The present research is a mixed qualitative and quantitative research method. In qualitative research, the Grounded theory method is a tool for building a conceptual model of manufacturing flexibility. ...
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The purpose of this article is to develop a model of manufacturing flexibility in the food industry. The present research is a mixed qualitative and quantitative research method. In qualitative research, the Grounded theory method is a tool for building a conceptual model of manufacturing flexibility. The statistical sample of this section includes 20 experts familiar with the subject of manufacturing flexibility. The sampling method in the qualitative section is the Snowball Sampling method. The method of data collection in this part of the interview is semi-structured. The method of data analysis in the qualitative part is a three-step process of open, axial and selective coding. The results of this section show the model of manufacturing flexibility paradigm. The data collection tool in the quantitative part is a researcher-made questionnaire based on sub-categories and concepts obtained from the qualitative stage. The method of data analysis in this section is confirmatory factor analysis and structural equation modeling. The statistical sample in this section is 201 managers of food industry companies in East Azerbaijan province. The results show that environmental dynamics, increasing competitiveness and access to new markets are among the reasons for the need for manufacturing flexibility, in which automation and timely production are considered as industry strategies to achieve manufacturing flexibility; These factors have a direct effect on increasing organizational performance and customer satisfaction as a consequence of flexibility. The results also show that intervenors such as managerial factors, financial capability, etc. can influence strategies.
Masoud Fazli; Ahmad GafarZadeh Afshari; Mostafa Hajiaghaei-Keshteli
Abstract
Green building has attracted widespread attention in recent years. Increasing building projects in Iran has had significant environmental impacts and green building implementation is an appropriate approach to reduce the environmental risks. Green building projects facing with risks unwittingly which, ...
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Green building has attracted widespread attention in recent years. Increasing building projects in Iran has had significant environmental impacts and green building implementation is an appropriate approach to reduce the environmental risks. Green building projects facing with risks unwittingly which, reduce their efficiency. Therefore, identifying and ranking the risks can play a significant role in the success of green building projects. Due to the few studies in this area in Iran, this study aims to provides a new comprehensive framework of all the criteria and risks of green building projects. For this purpose, the first step aims to identify and screen the risks from the viewpoint of experts in green building projects and introducing the risk assessment criteria. After that, the next step is to apply the SWARA method to obtain the weight of the criteria. Finally, Ranking of the risks of green building projects has been done using the COPRAS method. This is the first attempt to solve a green building project using a hybrid of SWARA and COPRAS through a case study (Amol). The results show that risks of: the low quality of materials and equipment, the stakeholder resistance to approve the green ideas and lack of realistic goals are very important. The proposed framework can help stakeholders of green building projects in developing countries to manage project risks more efficiently.
Zeinolabedin Akbarzadeh; Abdolhamid Safaei Ghadikolaei
Abstract
Today, one of the main concerns of managers interested in supply chain novel paradigms (SC) is identification of improvement priorities and determination of the focal points to promote the performance of SC. With studying effective practices performance in three echelons of Kalleh SC (first tier supplier, ...
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Today, one of the main concerns of managers interested in supply chain novel paradigms (SC) is identification of improvement priorities and determination of the focal points to promote the performance of SC. With studying effective practices performance in three echelons of Kalleh SC (first tier supplier, focal firm and first tier distributor), the present paper seeks to identify key components of LARG (Lean, Agile, Resilient and Green) SC and improve them in this company by developing a practical and strategic decision making model. The results show that the greatest gap in Pole Co. is in just-in-time production practices and the smallest gap is in the ability to reduce likely risks. In Kalleh Co., the greatest gap was found in close & long term relationship with suppliers and the least one was in the development of visibilities in SC. The greatest gap in Banichow Co, was quick responsiveness to customers and the least one was the ability to reduce of likely risks
production and operations management
Majid Shakhsi-Niaei; Fateme Ghayoor
Abstract
Aggregate production planning is a multi-objective problem which is influenced by managerial preferences which is rarely considered with these preferences in many researches. In this paper, a multi-product multi-objective aggregate-production-planning model has been proposed and implemented in an industrial ...
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Aggregate production planning is a multi-objective problem which is influenced by managerial preferences which is rarely considered with these preferences in many researches. In this paper, a multi-product multi-objective aggregate-production-planning model has been proposed and implemented in an industrial ball-valves manufacturing company. In the first phase, preferences of various product groups have been determined via a multiple-attribute-decision-making method which is used as an input for the second phase. To do this, one of the outranking methods has been used because of the variety in the dimension and the nature of different attributes. In the second phase, a deterministic multi-objective mixed-integer mathematical model has been designed considering the needs of the company. This model not only concentrates on the benefits, but also considers the preferences of the products. The third objective function is decreasing work in process. To solve this model, ϵ-constraint method has been used leading to a set of Pareto-optimal solutions, enabling the decision-maker to choose the best solution by trading off between the three objective functions. So top managers are able to decide how to provide product preferences and how to decrease WIP products while the benefits remain reasonable. The results show that using the proposed approach in the case study has improved 35%, 28%, and 56% total benefit, total utility, and WIP products, respectively.
Mohamad Taghi Taghavifard; Faezeh Abdoli Masinan
Abstract
The present research has done in Iran Insurance Company (Tehran Branch) in the year of 2016. The aim of this research is to study the effect of organizational social network features (Individual factors including: knowledge self-efficacy, enjoyment of helping and social factors include: social interaction ...
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The present research has done in Iran Insurance Company (Tehran Branch) in the year of 2016. The aim of this research is to study the effect of organizational social network features (Individual factors including: knowledge self-efficacy, enjoyment of helping and social factors include: social interaction ties, norm of reciprocity) on knowledge sharing activities and job performance. This applied research method is descriptive and survey. Literature review and field study have been used to collect information. The statistical population of this study included 230 employees (mainly experts) of Iran Insurance Company staff in Tehran. A group of 143 employees was selected as the sample for research through Cochran’s formula. Data was gathered by questionnaires and regression analysis was performed using SPSS and LISREL software to examine the hypotheses and Variables in quantitative method have been reviewed and evaluated by using structural equation and also confirmatory factor analysis. The results show that knowledge self-efficacy, enjoyment of helping, social interaction ties and norm of reciprocity have a positive effect on knowledge sharing activities which affect a person's job performance. Also, organizational social networks enable individuals to gather and share their work knowledge.
Akbar Moradi; Alireza Amirteimoori; Sohrab Kordrostami; Mohsen Vaez-Ghasemi
Abstract
Data Envelopment Analysis (DEA) is an estimator. This estimator tries to assess a relationship between multiple inputs and multiple outputs, and an identified technology. In traditional DEA models, firms are classified into two divisions, efficient and inefficient. Efficient firms are considered as a ...
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Data Envelopment Analysis (DEA) is an estimator. This estimator tries to assess a relationship between multiple inputs and multiple outputs, and an identified technology. In traditional DEA models, firms are classified into two divisions, efficient and inefficient. Efficient firms are considered as a reference for inefficient firms. In traditional DEA models, the efficiency improvement has been inspected for inefficient firms and efficient firms are assumed to be unchanged. Since the estimated technology is rationally smaller than the real technology or in other words, the estimated technology is always the subset of the true technology, we can expand it a little. Thus, we can improve efficient firms. This is done by creating some virtual DMUs. In this paper, an algorithm is proposed to expand the Production Possibility Set (PPS) and to improve efficient firms. To illustrate the proposed approach, numerical and applied examples are provided. The results are explained and discussed.
Vahid Hajipour; Sina Salimian
Abstract
Given the increase of natural disasters, the community's need for health services has increased dramatically. Firstly, the condition of the injured people should be determined and then the treatment should be start, and in the event of increasing in the severity of the injured, these people should be ...
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Given the increase of natural disasters, the community's need for health services has increased dramatically. Firstly, the condition of the injured people should be determined and then the treatment should be start, and in the event of increasing in the severity of the injured, these people should be transfer to the hospitals in the shortest possible time. On the other hand, another essential measure at the time of the accident is to send medicines and medical items at the appropriate time for treatment of injured. In this regard, we follow to design an emergency relief supply chain network including suppliers of medical items, treatment center, warehouses, and disaster points. Therefore, a location and inventory mathematical modeling is proposed to provide better services with the goal of minimizing the costs associated with locating and inventory of health systems. Thenو, to analyze and optimize the problem, proposed some numerical example and genetic algorithm.
Ali Akbar Mohamadian; Masoud Simkhah
Abstract
Supplier selection is one of the most important problems in the field of management and optimization. It aims to optimize the cost of supply, quality of products and services, and the risk of non-supply, among others. However, existing models often overlook the risk of non-supply and the brand effect ...
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Supplier selection is one of the most important problems in the field of management and optimization. It aims to optimize the cost of supply, quality of products and services, and the risk of non-supply, among others. However, existing models often overlook the risk of non-supply and the brand effect on demand. In this research, a supplier selection integer model is developed that considers lead time and the risk of non-supply. To solve this model, the LOKAD benchmark database is utilized, and a new adaptive variable neighborhood search algorithm is introduced, incorporating a scoring strategy to handle the model's complexity and obtain optimal or near-optimal solutions. The obtained Pareto solutions outperform traditional results, as confirmed by the Wilcoxon test. Sensitivity analysis of the solutions on the budget demonstrates that the final profit is more sensitive compared to lead time. Furthermore, distance from the ideal and diversity measures are used to quantitatively compare the results. IntroductionSupplier selection involves identifying, evaluating, and contracting with suppliers to meet an organization's requirements for raw materials and related infrastructure. It plays a crucial role in financial resource allocation and product/service quality. The main objectives of supplier selection include reducing purchasing risks, minimizing lead time, and enhancing quality. Many organizations face multiple criteria for selecting suppliers, such as receipt risk, green criteria, and lead time. Mathematical modeling and optimization techniques are commonly employed to achieve these objectives. However, existing models often lack real-case assumptions, motivating researchers to extend models in this environment. This research addresses these gaps by developing a mathematical model for supplier selection that considers the risk of non-supply and the substitution rate of inventory-less products. Materials and MethodsTechnically, the conducted modeling is a quantitative research in which data has been collected using library-based tools. Additionally, the statistical population corresponds to the LOKAD company, and a sample of its information is publicly available and will be utilized in the numerical computations phase of this research. This research develops a novel supplier selection multi-objective mathematical model that considers the risk of non-supply and substitution rate of demand when a product is inventory-less. Additionally, a modified adaptive variable neighborhood search (AVNS) algorithm is proposed to solve the model. While the focus of this paper is on the retail industry, the proposed model can be adapted to any industry. Discussion and ResultsThe developed model will be solved using data related to the LOKAD company, which was collected during a one-year period in 2018. This dataset includes sales and purchasing information of products related to the LOKAD company, encompassing details about the suppliers of the products and their brands. The utilization of this dataset is due to the fact that many articles have made use of it for its detailed information provided by the LOKAD company. In order to compare the method, the Wilcoxon test is used to compare two groups of variables, which can determine the presence of a difference between them. The observations reveal that the substitution rate of demand significantly affects the results and can alter the selection of final suppliers. Budget limitations are another important factor, where increasing the budget leads to higher profits by enabling the selection of more competent suppliers and high-quality products for customers. ConclusionsSupplier selection is a challenging problem in various industries. The experiments conducted in this research demonstrate that increasing the budget limitation results in higher profits, as customers prefer products or services with higher levels of quality. The developed mathematical multi-objective model incorporates real-case assumptions such as the risk of non-supply and substitution rate of demand. The model is solved using the proposed modified AVNS algorithm. The solutions obtained are analyzed using mean ideal distance and diversification metric measures to ensure their reliability. The analysis highlights the significance of budget limitations, which outweighs the impact of lead time in supplier selection problems. Ultimately, the model provides an optimal combination of suppliers. Additionally, the sensitivity analysis performed on the budget constraint reveals that changes in the budget have a greater impact on the final profit compared to lead time. The proposed model effectively determines the allocation of purchases from each supplier to enhance the final profit. In this regard, an initial estimation of future demand is considered as deterministic, although transforming this parameter into a probabilistic form can make the model more robust.
Amir Yousefli; Vahid Karimpour Khameneh; Reza Norouzi
Abstract
Refineries, including the conversion industries, use oil and gas as row materials and their production processes and products could be so harmful to the environment if they could not manage properly. Nowadays, these companies are working hard to minimize the environmental damages caused by their products, ...
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Refineries, including the conversion industries, use oil and gas as row materials and their production processes and products could be so harmful to the environment if they could not manage properly. Nowadays, these companies are working hard to minimize the environmental damages caused by their products, production processes, supply chain, distribution methods and etc. The first step to manage environmental impacts properly, is considering the current condition and correct evaluation of products. In this paper a new method is presented to evaluate the refinery products degree of greenness. The developed model consists of influencing parameters on greenness degree, which are classified in a hierarchical structure. Due to the difficulties in defining an explicit function, fuzzy controllers are implemented to infer degree of greenness based on influencing parameters values. Effectiveness of the presented model is evaluated by assessing the greenness degree of Bandar Abbas refinery products and the results reflect good performance of the developed model.
Neda Manavizadeh; soroush aghamohamadi-bosjin; Parisa Karimi-Ashtiani
Abstract
This paper proposes a bi-objective model for the waste collection problem and considers the location, routing and inventory of the system simultaneously. Considering the reverse flow of the system is another feature of the current study. In the proposed model, the total costs of the system are minimized. ...
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This paper proposes a bi-objective model for the waste collection problem and considers the location, routing and inventory of the system simultaneously. Considering the reverse flow of the system is another feature of the current study. In the proposed model, the total costs of the system are minimized. In addition, the related risks of opening new centers and transportaion are included as the second objective function of the problem. Considering the delivery time and cpacity of vehicels constraints, are the other features of the model. Due to the NP-hardness of the model, two metaheuristic algorithms namely a non dominated sort ordering genetic algorithm (NSGA-II) and a multi objective particle swarm optimization algorithm (MOPSO) are applied to solve the problem. According to the results, NSGA-II is able to reach better answers in all the propsed metrics. According to sesitivity analysis, foreign transportation fleets make a great impact on the costs of the system.
production and operations management
Mahsa Sobhi shojaa; Parvaneh Samouei
Abstract
In the recent years, robots have been widely used in assembly systems as called robotic assembly lines where a set of tasks have to be assigned to stations and each station needs to select one of the different robots to process the assigned tasks. Our focus is on u-type layouts because they are widely ...
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In the recent years, robots have been widely used in assembly systems as called robotic assembly lines where a set of tasks have to be assigned to stations and each station needs to select one of the different robots to process the assigned tasks. Our focus is on u-type layouts because they are widely employed in many industries due to their efficiency and flexibility . In these lines, a worker can be assigned to multiple stations located at entrance and exit sides. However, in many realistic situations, robots may be unavailable during the scheduling horizon for different reasons, such as breakdowns. This research deals with line balancing under uncertainty The Objective in this research is minimizing the cycle time for a given number of workstations and minimizing robot cost.This research deals with line balancing under uncertainty and presents one robust optimization model for balancing and sequencing of u-shaped robotic assembly line with considering set up times between task, failure robot times and preventive maintenance times for every robot. Since the NP-hard nature of the problem, multi-objective harmony search is developed to solve it. Numerical experiments also demonstrated that by increasing uncertainty level, the objective function values, cost and cycle times (minimum, maximum and average) increased. performance of the robust approach by the results, shows that in real conditions, considering the probability of event failure, values of cycle time and cost change significantly, which indicates the need to consider uncertainty, especially failure in robotic assembly lines.
Mahdi Haghighi Kaffash; Zhre Dehdashtishahrokh; Vahid Khashei; Reza Hajari
Abstract
This study is conducted to identify and analysis the relationship between the factors affecting the distribution network design (DND) in the food distribution industry in Iran. In this paper, the distribution network design has been classified into two main areas of the strategic structure of the distribution ...
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This study is conducted to identify and analysis the relationship between the factors affecting the distribution network design (DND) in the food distribution industry in Iran. In this paper, the distribution network design has been classified into two main areas of the strategic structure of the distribution network and the distribution management policies and the impact of the key variables on distribution network design has been investigated. This study is descriptive, exploratory and using quantitative research method. The statistical population of this research is all 54 food distribution companies in Iran. Using a census method, a questionnaire was sent to all general and marketing managers of these companies (108 people). 92 questionnaires were completed, according to the established criteria, only 81 questionnaires could be used, which also covers the standards of Cochran formula. The partial least squares (PLS) method is used to analyze the data and the results show that product characteristics, service requirements, demand characteristics, supply characteristics, and economic variables are the key variables that affect the distribution network design. Given the lack of research on the distribution network design and the study of the factors affecting the formation of strategic distribution structures and policies, it can be argued that this article provides valuable insights for academics and professionals, because in many studies the various components of distribution network design, the decisions related to the design of the distribution network and the analysis of the main factors affecting the distribution network structure are presented
