Shima Salehi; Mohammad Taghi Taghavifard; Ghanbar Abbaspour esfeden; a alirezaee
Abstract
The integration of supply chain decisions aims to reduce costs and delivery time for customers. However, uncertainty in supply chain parameters, particularly demand, can disrupt this integration. The increased interest in probabilistic planning and simulation models in supply chain modeling is a response ...
Read More
The integration of supply chain decisions aims to reduce costs and delivery time for customers. However, uncertainty in supply chain parameters, particularly demand, can disrupt this integration. The increased interest in probabilistic planning and simulation models in supply chain modeling is a response to this demand uncertainty. Therefore, the main objective of this study was to develop a multi-level, multi-product, multi-period supply chain network model that considers conflicting objectives such as cost minimization, delivery time minimization, and system-wide reliability maximization. The supply chain network under investigation consisted of four levels or subsystems: suppliers, manufacturers, distributors, and retailers. In this study, it was assumed that demand follows a random probabilistic distribution function. Consequently, simulation techniques were employed to estimate costs, including shipping costs, lost sales costs, and other expenses. After developing the multi-objective model, various scenarios were created based on different perspectives of inventory levels, namely minimum inventory, maximum inventory, and average inventory level. For each scenario, objective-related values were estimated. Ultimately, based on the Pareto optimal solutions obtained for each case of the model, the Vickor decision-making method was used to rank the answers and select the best solution from the proposed model. The results indicated that the second scenario, considering the average inventory level, was identified as the optimal solution for the described model.IntroductionToday, supply chain management (SCM) encompasses the entire production planning process for the supply chain, from raw material suppliers to the final customer. This has become a focal point for numerous researchers. In most supply chain designs, the objective has been to transfer products from one layer to another in order to meet strategic, tactical, and operational demands while minimizing complications arising from interrelationships and uncertainties across the chain. These challenges have posed significant decision-making hurdles in the supply chain domain. Supply chains can be regarded as complex systems wherein various factors interact with each other, resulting in emergent properties. Designing a versatile supply chain to address conflicting and diverse objectives requires considering them simultaneously and striking a balance among different criteria. The dynamic and intricate nature of the supply chain introduces a high level of uncertainty, thereby impacting the decision-making process in supply chain planning and influencing overall network performance. Based on the aforementioned issues, the focus of investigation includes the following: The examined supply chain network comprises four levels or subsystems, namely suppliers, manufacturers, distributors, and retailers. Raw materials are sourced from suppliers and sent to production factories, where each product is manufactured using a specific combination of raw materials. The products are then transported from manufacturers to distribution centers, and subsequently forwarded to retailers. The market is divided into different regions, and customer demands are fulfilled through visits to the retailers. Demand is assumed to be random and follows a probability distribution pattern. Consequently, simulation techniques are employed to estimate costs, including transportation costs, lost sales costs, and other expenses. Scenarios are created based on different perspectives at each level, focusing on inventory levels (minimum, maximum, and average). For each scenario, the values associated with the investigated objectives are estimated.Materials and methods In this research, data collection involved the examination of relevant literature, including articles published in international journals, books, and treatises. Documentary studies were conducted to gather information. To analyze the collected data, simulation and multi-objective programming concepts and methods were employed. Minitab and ED software were utilized for statistical analysis and simulation purposes.ConclusionsConsidering that the model can be solved under different conditions, including the current situation and various scenarios, the answers obtained for each state are Pareto optimal. This means that it is not possible to determine a single best answer for each state of the model. Therefore, before comparing the scenarios with each other, the Pareto optimal answers for each scenario should be ranked to identify the best options. In this research, a model for designing the supply chain network was presented, taking into account demand randomness. To better understand the proposed model and demonstrate its practicality, numerical examples were examined and evaluated using different scenarios and the Lingo software. It is important to note that the developed model in this study is independent of the number of facilities at each level of the supply chain and the parameter values. Therefore, the general form of this model can be applied to any production environment that aligns with the patterns presented in this research. The proposed model initially employed the design of experiments to estimate the mathematical relationship related to the cost objective function. After developing the multi-objective model, the Lingo software was used to solve the sample problem and evaluate the results under different scenarios. Finally, based on the Victor decision-making method, the Pareto optimal solutions for each state of the model were used to rank the answers and determine the best mode for the proposed models. Based on the obtained results, the third option or the second scenario is suggested as the preferred choice for the described model, considering the index values associated with each option
supply chain management
Ali Mahmoodirad; Ali Tahmasebi Notareki; Sadegh Niroomand
Abstract
The closed-loop supply chain is used in practice for several reasons. Firstly, returning products to the production cycle is important for its operation. Secondly, sustainability in the supply chain is a topic of interest for researchers, as the environmental impacts of industries are significant. In ...
Read More
The closed-loop supply chain is used in practice for several reasons. Firstly, returning products to the production cycle is important for its operation. Secondly, sustainability in the supply chain is a topic of interest for researchers, as the environmental impacts of industries are significant. In this paper, a multi-objective integer fuzzy mathematical programming model is presented to design a sustainable closed-loop supply chain under uncertain conditions. The proposed model aims to maximize profit and social impacts, while minimizing gas emissions into the environment. Since decision makers face uncertainty and doubt, trapezoidal intuitionistic fuzzy numbers are employed to determine the parameter values in the model. To convert the objective functions and model constraints into crisp forms, the expected value and the intuitionistic credibility measure are developed for the objectives and constraints, respectively. Finally, an interactive fuzzy programming approach is utilized to solve the crisp multi-objective problem. Three numerical examples are designed and solved to validate the model and assess the efficiency of the proposed solution method.IntroductionSupply chain management encompasses techniques aimed at coordinating all aspects of the supply chain, from raw material procurement to product delivery or recovery, with the objective of minimizing total costs while addressing conflicts among chain partners. Once raw materials have traversed the forward chain and been transformed into products or services, they may require repair, transformation, or proper disposal, which occurs within the reverse chain. The integration of forward and reverse supply chain methods gives rise to a closed-loop supply chain.Today, one of the primary concerns for organizational managers in supply chain network design is the presence of uncertainties, such as disruptions and uncertain input parameters. Uncertainties can have adverse effects on supply chain performance and decision-making at various network levels, including tactical, strategic, and operational decisions. As probabilistic planning necessitates historical data, which may not always be available or accurate, the theory of fuzzy sets can serve as a suitable option for expressing ambiguity and lack of certainty in parameters. In recent years, environmental factors have received increasing attention. There has been a growing recognition of the importance of environmental effects and the need to incorporate these effects alongside traditional indicators in supply chain design. Environmental considerations are crucial not only for compliance with government regulations but also for improving the organization's social standing from the customers' perspective. Moreover, with the rise of global warming and the accumulation of waste (both renewable and non-renewable, as well as electronic waste and ozone-depleting gases), the importance of managing and controlling these factors has become even more prominent. Despite the significance of environmental issues, there remains a noticeable gap in the supply chain literature concerning the provision of mathematical models based on real-world conditions and efficient solution methods for this problem. This paper focuses on the design of a sustainable closed-loop logistics network that aims to maximize profitability and social factors while minimizing environmental factors. The proposed integrated network considers multi-product and multi-state customer demand under conditions of uncertainty. The significance of this research lies in simultaneously addressing economic, environmental, and social considerations in the modeling process, as previous studies have mostly focused on single or dual objectives. Another innovative aspect of this article is the consideration of parameters in the form of intuitive fuzzy numbers for the design of a sustainable supply chain network.Materials and MethodsIn this research, a comprehensive model addressing the problem of sustainable closed-loop supply chain under intuitionistic fuzzy uncertainty is selected through library studies and internet research. Subsequently, the model is transformed into a deterministic multi-objective model utilizing the intuitionistic credibility measure. Recognizing that decision makers face not only uncertainty but also doubts, trapezoidal intuitionistic fuzzy numbers are employed to determine parameter values within the proposed model. To convert the objective functions and model constraints into their crisp equivalents, the expected value and intuitionistic credibility measure are respectively developed for the objective functions and constraints.FindingsBased on the selected confidence levels and numerical examples, the following observations can be made: In numerical example 1, the first objective function demonstrated that the ABS, SO, and TH methods performed best, respectively. However, in the second objective function, the order shifted to SO, ABS, and TH. Interestingly, all three methods performed equally in the third objective function. The performance of the solution methods in numerical example 2 mirrored that of numerical example 1. Moving on to numerical example 3, the first objective function indicated that the SO, TH, and ABS methods were the most effective, respectively. The order remained similar in the second objective function, and once again, all three methods performed equally in the third objective function. These results indicate the relative superiority of the SO solution method compared to the other methods employed. Additionally, concerning the execution time of the solution methods, numerical examples 1 and 2 exhibited nearly equal execution times for the methods. However, in numerical example 3, the SO, TH, and ABS methods displayed the best performance in terms of execution time, respectively. These findings further emphasize the relative superiority of the SO solution method compared to the others in terms of execution time. It is worth noting that the execution time of each method alone increases significantly with the problem's dimensions across all numerical examples.ConclusionsThis paper presents a multi-objective fuzzy optimization model for the design problem of a sustainable closed-loop supply chain. The model takes into account the concept of sustainability and aims to maximize the income and minimize the costs of the entire supply chain, while also minimizing environmental effects and maximizing social effects. The parameters are considered uncertain and are represented by intuitionistic trapezoidal fuzzy numbers. To handle this uncertainty, the model is transformed into a deterministic multi-objective optimization model using the expected value definition and a chance constraint based on the size of intuitionistic. The obtained deterministic multi-objective model is then solved using the interactive fuzzy mathematical programming method.
supply chain management
Homa Abedi Dehkordi; Ghasem Tohidi; Shabnam Razavyan; Mohammad Ali Keramati
Abstract
Cement production in Iran takes place across various geographical locations, each characterized by distinct weather conditions. The technology employed in cement production varies depending on the availability of raw materials, fuel sources, and essential resources like water. Consequently, diverse inputs ...
Read More
Cement production in Iran takes place across various geographical locations, each characterized by distinct weather conditions. The technology employed in cement production varies depending on the availability of raw materials, fuel sources, and essential resources like water. Consequently, diverse inputs and outputs assume significance in each production technology, resulting in non-homogeneity among cement factories. Despite these differences, all these facilities are engaged in cement production, warranting a comparative analysis of their efficiency. This study examines the operational processes of five different cement production technologies—dry, semi-dry, humid, semi-humid, and wet slurry—across four companies comprising a total of nine factories. The study evaluates their efficiency between 2017 and 2020 using network data envelopment analysis under non-homogeneous conditions across three modeling stages. An important aspect of this study is its focus on the entire supply chain, from raw materials to the final product. Although the raw materials employed vary among different cement production technologies, the end product remains largely consistent.IntroductionIn certain real-world scenarios, even with similar production technologies, the assumption of homogeneous decision-making units may not hold true. Practical applications often involve supply chain structures that differ significantly from others. For instance, some supply chains may, at certain stages, eject intermediate products to meet specific needs, a phenomenon not universal to all supply chains, resulting in non-homogeneous chains. The cement industry, including Iran, constitutes one of the pivotal economic sectors. Therefore, mitigating shortcomings, including resource and material waste reduction, can have a substantial impact on this industry and consequently on the broader economy. Due to varying climatic conditions, cement production employs diverse technologies, primarily categorized as dry or wet processes. This study investigates the operational processes of five different cement production methods—dry, semi-dry, humid, semi-humid, and wet slurry—across four companies with a total of nine factories. Their performance between 2017 and 2020 is evaluated using network DEA under non-homogeneous conditions, encompassing three modeling stages.Materials and MethodsIn novel approaches, DEA is utilized to assess the performance of network decision-making units. The models typically assume homogeneity among decision-making units, which may not always align with real-world conditions. Practical situations often violate assumptions of unit homogeneity and uniformity in input and output parameters. Consequently, it is imperative to present and employ methods and models capable of accommodating non-homogeneous units. This study employs a scientific library research approach and practical purposive data collection to gather relevant information. This information informs specific adjustments to operational processes. Consequently, the development of a robust system for evaluating supply chain performance becomes essential. The study utilizes common models to evaluate efficiency under non-homogeneous conditions. Classification of operational processes and related data, followed by modeling using Lingo software, is employed in this research.Discussion and Result:This article consists of two parts. Initially, it introduces the fundamental performance evaluation model and subsequently delves into the three-stage model of data envelopment analysis (DEA) within the supply chain context. In the second part, the production processes of Portland cement are examined, covering dry, semi-dry, humid, semi-humid, and wet slurry processes. The proposed approach assesses the performance of four cement production companies over a four-year period. Efficiency calculations for nine factories are conducted in three stages:The first stage consists of three steps as follows:First step: Input and output parameters used across the entire production process are categorized based on the different production methods.Second step: Processes utilizing similar production steps, as determined in the first stage, are grouped into four categories.Third step: Efficiency assessments for factories sharing similar production stages from the previous step are conducted, resulting in the identification of nine categories.Second stage: The efficiency of each category, characterized by a common feature from the previous step, is calculated.Third stage: To determine the overall efficiency of each factory, the efficiencies of individual processes are multiplied.ConclusionsThe results indicate that the fourth cement production company exhibits the highest efficiency, while the first company has the lowest efficiency. Notably, the lowest efficiency for the years 2017 to 2020 was recorded by the first company in 2020, while the fourth company achieved the highest efficiency in the same year. Among the factories, the lowest efficiency was observed in 2017 for the first company's five semi-dry factories, the fourth company's four semi-humid factories in 2018, the fourth company's nine wet slurry factories in 2018, the third company's seven semi-humid factories in 2020, and the fourth company's four semi-humid factories in 2020, which recorded the highest efficiency. Further examination and identification of suitable solutions to enhance efficiency in cases with lower efficiency levels can follow this study.
vajhollah ghorbanizadeh; Mohammad Amini; Jafar Rashidi
Abstract
There is a serious competition between Allameh Tabataba'i, shahid Beheshti, and Tehran Universities to attract the best students. In other side, students have considered several indicators to choose university for higher education. The aim of this research is to determine management faculties’ ...
Read More
There is a serious competition between Allameh Tabataba'i, shahid Beheshti, and Tehran Universities to attract the best students. In other side, students have considered several indicators to choose university for higher education. The aim of this research is to determine management faculties’ competitive position in these Universities and also to find an answer to this question: what is the position of Allameh Tabataba'i University postgraduate students compared to two other universities based on variables such as: rank of entrance examination, number of acceptance , average of undergraduate scores, type of undergraduate university, relationship between educational field in BS and MA, and students age. This practical research uses descriptive study and has comparative approach. The data was collected from three management faculty for 2009 to 2014. The findings indicate that Allameh Tabataba'i University has accepted MA students in management more than two other universities and its MA students have lower average of entrance examination rank. There were no main distances on average of undergraduate scores and MA students’ age between these universities. There were similar situations about the other variables
Ali Bonyadi Naieni; Sirous Amirghodsi; Ahmad Makui
Abstract
One of the important decisions in the supply chain is the supplier selection affecting different sectors and objectives of a chain significantly. In supplier selection area, product/technology selection, product/technology transfer method selection, and product/technology supplier selection are three ...
Read More
One of the important decisions in the supply chain is the supplier selection affecting different sectors and objectives of a chain significantly. In supplier selection area, product/technology selection, product/technology transfer method selection, and product/technology supplier selection are three debatable factors. Hence, in this paper, criteria influencing these three indicators will be identified and their importance will be ranked by Gray-DEMETEL and Best-Worst Method (BWM). Then, the priority of the options will be determined using Gray Analytical Network Process (GANP), which is one of the strongest decision-making methods. This paper attempts to demonstrate the superiority of the BWM method in determining the importance of criteria while comparing previous methods in this group. The compliance rate obtained for the BWM confirms this claim. In order to investigate the proposed approach, a case was conducted with 5 final suppliers, 3 technologies and 5 technology transfer methods, which ended with the selection of the best supplier with the highest technology and capable of transferring the technology by the optimal transfer method.
project management
Ali Namazian; Somayeh Behboodian
Abstract
Projects, during their execution, face various risks that can impact the achievement of project objectives. Therefore, the need for extensive project risk management is widely recognized. In a systematic risk management process, after risk evaluation, risk analysts are confronted with the risk response ...
Read More
Projects, during their execution, face various risks that can impact the achievement of project objectives. Therefore, the need for extensive project risk management is widely recognized. In a systematic risk management process, after risk evaluation, risk analysts are confronted with the risk response phase, where they decide on the actions to be taken regarding identified risks. Hence, designing and implementing a structured approach to manage and mitigate risks will yield beneficial outcomes for successful completion within the desired budget, time, and quality. In conducted studies, a comprehensive approach that integrates the time and cost implications of risks and response strategies has been lacking. In this article, an optimization model of zero-one programming has been employed to select the most suitable risk response strategies for the project. In the developed framework, the modeling of the impact of risks on the time and cost of activities, as well as the effect of implementing risk response strategies on reducing the undesirable time and cost implications of risks, has been utilized to select optimal strategies. Finally, to evaluate the efficiency of the model, an industrial case study was utilized, which confirmed the favorable performance of this framework.IntroductionEvery project throughout its lifespan faces opportunities and risks. Risks are uncertain outcomes or consequences of activities or decisions. Therefore, in the project planning process, it is necessary to identify potential risks and then consider appropriate strategies to deal with various risks. In this article, a mathematical programming model is used to evaluate and analyze project risks and to select project risk responses. This model considers the probabilistic nature of risk events and develops an index for evaluating the time and cost impacts of risks, as well as response strategies. The proposed approach can be used to select the best combination of risk response strategies that have the most impact on the time and cost of implementing activities, resulting in completing the project with minimum time and cost.Literature ReviewDifferent models have been developed for project risk management to enhance success in development projects. These approaches utilize various structures and tools to quantitatively or qualitatively model the selection of risk response strategies for the project. In recent years, due to unexpected events such as financial crises, significant delays have occurred in projects worldwide (Motaleb, 2021). Thus, researchers have attempted to propose various methods to mitigate the effects of risks in recent years.In the Zonal-based approach, two selected criteria based on risks are plotted on the horizontal and vertical axes, respectively. The two chosen criteria are the weighted probability of immediate project risk and external project risk, and the controllability and specificity of the risks related to the project. Based on the different values of these two criteria, a two-dimensional chart consisting of multiple regions is formed. Different strategies are placed in the corresponding regions. Therefore, suitable strategies can be selected based on the regions formed by the coordinates of the two criterion values.In the Trade-off-based approach, in order to identify the selected risk for formulating response strategies, exchanges are conducted considering the project's goals, requirements, and managers' mental settings among risk-related criteria such as cost, success probability, percentage of work losses, duration, quality, etc. Then, desirable strategies can be selected from the options based on the efficiency frontier rule.The approach based on WBS is considered a risk management and project management method. This choice aligns the risk response strategy with the work activities based on WBS analysis of the project. (Guan et al., 2023) developed an integrated approach based on an optimization model and fault tree analysis for budget allocation in response to risk from safety and prevention perspectives.The optimization approach involves creating a mathematical model to solve the problem of selecting risk response strategies. In general, the objective function aims to minimize the cost of implementing strategies, and the constraints include combinations of strategies, an acceptable level of risk loss, budget for implementing strategies, etc.MethodologyIn this study, a set of work activities is considered, and for each work activity, there may be associated risks that can have an impact. Then, risk response strategies are modeled to determine the most desirable strategy. The zero-one programming technique is used to solve the model. By solving the model, strategies are selected that maximize the estimated impact of risk response after implementation and minimize the cost of implementation. In the proposed model, a set of actions is selected in a way that satisfies the system constraints and optimizes the corresponding objective function. The objective function can be related to time or cost, and the goal of the model is to minimize project completion time or project cost. The model constraints are related to time and cost. The time constraint means that selected strategies should not exceed the specified time frame for their execution and impact on time. The cost constraint means that selected strategies should not exceed the budget and predefined cost in terms of their cost and impact on cost. ResultsThe model presented in this study has an objective function and nine constraints. The purpose of this model is to determine strategies that minimize project completion delay and help achieve and improve project goals. Due to the structure of the modeling, including the objective function and problem constraints, the complexity of the model will change polynomially based on the number of risks, response strategies, and project activities. If simulation-based approaches are used to solve the model, considering the binary nature of project risks and replacing it with the expected value, the complexity of the solution approach will be exponential. Therefore, using the logic of expected value to calculate the duration of activities and project completion time will accelerate the solution process.Discussion and conclusionsIn a systematic project risk management process, after assessing the risks, the implementation of project risk response strategies takes place. The conducted research has generally provided general solutions, and there is no comprehensive model for evaluating project risk reduction measures. In this article, a mathematical optimization model has been developed by considering the risks and response strategies as independent variables for each work activity. Essentially, based on the potential risks that may occur for each work activity, strategies are chosen to minimize project completion delay and reduce the incurred costs, ultimately achieving the project's completion with the least delay and cost. Implementing risk response strategies to mitigate the time and cost impacts of risks requires time and investment. Therefore, selecting these strategies will be justifiable when the time and cost benefits derived from their implementation are greater than the time and cost spent.
production and operations management
fahimeh tanhaie
Abstract
The mix model assembly line has attracted the attention of many industrial manufacturers due to its special features and the ability to adapt to market changes. This article has discussed and investigated a new approach in relation with customers, the results of which indicate the proper management of ...
Read More
The mix model assembly line has attracted the attention of many industrial manufacturers due to its special features and the ability to adapt to market changes. This article has discussed and investigated a new approach in relation with customers, the results of which indicate the proper management of demand. The proposed model pays more attention to priority customers, and a parallel production line is defined that is faster than the main line and has workers with special skills. According to the rapid process of environmental changes, one of the things that can be considered to increase flexibility in the make to order environment is to set the conditions for rebalancing the line. In this article, the rebalancing of the line is also considered and included in the modeling, and the minimization of its costs is considered as another goal. Therefore, in this article, a multi-objective line balancing problem is proposed by examining rebalancing and vertical balancing problems. Benders decomposition algorithm is used to solve this problem. The results show that exact methods do not have the ability to solve large-sized problems in a reasonable time, but the solution time for Bander's decomposition method, considering the size of the problem, shows the appropriate efficiency of this algorithmIntroductionMix model assembly lines, known for their ability to adapt to changing market demands with minimal adjustments, are currently employed in active industries worldwide. The findings of this article also hold potential for reducing assembly line waste in the country's manufacturing sector. Drawing from the principles of lean production and the theories of Scholl and Becker, achieving an optimal production line balance can lead to the reduction of at least five out of the ten types of waste. While the topic of line balancing is crucial in itself, this research sheds light on a significant aspect often overlooked in most studies on planning mixed model assembly lines: the order-based environment. Many previous studies have focused solely on the 'make-to-order' environment and its assumptions, often neglecting balance issues. Given the paramount importance of customer roles in industries, it is imperative to introduce a framework for managing customer orders within line balancing problem models. The aim of this article is to enhance cost management and productivity in mixed assembly lines across various industries, ensuring that demands are met and assembly process constraints are addressed. To achieve this, we first develop the necessary mathematical models for each component and subsequently devise algorithms for their solutions.Materials and MethodsAn express line is defined in parallel and faster than the main line, as well as having workers with special skills. Considering the rapid process of environmental changes, another thing that can be considered to increase flexibility in the base order environment is to create conditions for rebalancing the line so that both the workload and the cost can be balanced at the same time. This reduced the reassignment of duties. From this point of view, in the proposed model in this part, rebalancing of the line is also desired and it is included in the modeling, and the minimization of its costs is considered as another goal of this model. Also, the goal of balancing the assembly line, which is to distribute the total workload between the stations as smoothly as possible, is also included in the proposed model of this part, which is also called vertical balance, so that each station has a balanced amount of work. Be in a work shift. Therefore, in this model, a multi-objective problem of determining the balance is designed by examining the problems of rebalancing and vertical balance. The orders coming into the organization are prioritized first, because in the order-based production environment, the delivery time of orders is very important, especially for high-priority orders, because customers expect an appropriate response in a short period of time. This prioritization can be done by any method, the output of which determines regular customers and priority customers. After determining the priority of the orders and paying attention to the main line and the designated vanguard, priority orders can be entered into the Parallel line, which operates faster and has multi-purpose operators.Discussion and ResultsIn order to validate the model and ensure the correct performance of the combined benders algorithm with the LP metric method, first the mathematical model in a small size is solved and a comparison between the results and the proposed algorithm is done. Finally we used the proposed algorithm in the large size that the gams software is not able to determine the answer. The L-P metric method obtains the optimal solution in small sizes, but in large sizes, when we give 3600 to 10800 seconds to the solver, it cannot obtain the optimal solution and requires another method to solve. The results of the comparisons show that the LP-metric method does not have the ability to solve large-sized problems in a reasonable time, but the solution time for the benders decomposition method, considering the size of the problem and the obtained answers, shows the appropriate efficiency of this algorithm.ConclusionsFlexibility in the production lines is very important and it should be able to respond to the demand when customer orders change. Therefore, the definition of a mix model line provides flexibility in responding to customer demand and reducing the delivery time for priority orders. When we are faced with a large volume of orders, it can be useful to do things in parallel line. This issue, which is rarely seen in research, is presented in the balance model of this article in the form of two parallel lines. This issue is especially effective in industries such as automobile manufacturing.
Mehdi Yazdani; Mahshid Aioobi; Amin Ghoroori
Volume 8, Issue 21 , June 2011, , Pages 131-142
Abstract
Some real world problems include determining optimum values of lput variables in order to obtain the desired levels of output variable response surface variable). One of the applicable techniques which are set for modeling and solving such problems is Response Surface methodology (RSM). In this paper, ...
Read More
Some real world problems include determining optimum values of lput variables in order to obtain the desired levels of output variable response surface variable). One of the applicable techniques which are set for modeling and solving such problems is Response Surface methodology (RSM). In this paper, the effect of three controllable lput factors: temperature, the density of sodium cyanide, and ampere n the determined response surface level i.e. the thickness of the electroplating cover of a hook screw is checked by Design Of experiments (DOE). After the execution of experiments and the ^cognition of effective factors, according to the application of response surface methodology, the relationship between the variables f effective input factors and the response surface variable is stermined with the help of nonlinear regression model. Then, the Optimum value of each variable in nonlinear model is obtained by goal pogromming method.
ali seyyed naghavi; mohammad mahdi bahrololoum
Volume 11, Issue 28 , April 2013, , Pages 137-158
Abstract
One of the effective key factors in differentiating and outrunning competitors is the continuous delivery of superior quality to the customers. The secret of success is meeting or getting ahead of customer’s expectations in relation to service quality. By considering the fact that service quality ...
Read More
One of the effective key factors in differentiating and outrunning competitors is the continuous delivery of superior quality to the customers. The secret of success is meeting or getting ahead of customer’s expectations in relation to service quality. By considering the fact that service quality plays an important role in the success of today’s organizations, this article pursues the purpose of investigating the dimensions that have effect on technical services quality of petrochemical commercial company’s sale engineering department, determining the most important service quality dimensions, measuring the gaps existing in the service delivery system and finally promoting and improving the current status of the system. We used the Servqual Model to assess the quality of the services. In this study we tried to customize the model to adapt the specific conditions of the organization, so the Tangibles dimension of the standard model was replaced with service variety and confirmatory factor analysis approach was used to examine the theoretical model of the study. The modified model was analyzed by Lisrel and its validity was confirmed from a statistical point of view. The results of data analysis by SPSS showed that the sale engineering department’s service delivery system was encountered with problems and so the existence of service gaps was proved. Finally practical solutions were provided to promote the service quality and improve the current status of the system
hamid reza fartook zadeh; mahdi elahi
Volume 11, Issue 29 , July 2013, , Pages 139-154
Abstract
As the most important institutions, Banks face different risks. As a matter of fact, risk is the results of the internal – external elements and the stakeholder’s expectations of the current and future status of the banks which are active in the country.
Under a poor management some of this ...
Read More
As the most important institutions, Banks face different risks. As a matter of fact, risk is the results of the internal – external elements and the stakeholder’s expectations of the current and future status of the banks which are active in the country.
Under a poor management some of this risks which forces called strategic risks may cause bankruptcy.
One characteristic of mature banks is the development of a certain integrated processes of risk management .Due to the necessity of applying this approach in banking, we chose the Mellat Bank as a case study in this article.
Our goal in this research was acquiring knowledge of banking experts to reveal and document strategic risks by use of Delphi methodology. This research is up to identify and rank the strategic risks of Mellat Bank and draws the strategic risk map
Zohreh Dehdashti Shahrokh; Hossein Jafari
Volume 9, Issue 24 , March 2012, , Pages 141-160
Abstract
One of the most important concepts of international marketing is export target market selection which is the first stage of internationalization process. This paper studies the factors influencing export target market selection in Iranian electrical industry. The factors categorized in 6 dimensions such ...
Read More
One of the most important concepts of international marketing is export target market selection which is the first stage of internationalization process. This paper studies the factors influencing export target market selection in Iranian electrical industry. The factors categorized in 6 dimensions such as politics, market potential, economics, culture, infrastructure and legal and were tested and prioritized from experienced exporter’s perspective. Top managers of exporting companies in the electrical industry were surveyed through census method. The ranking method was used for analyzing the data. The results showed that market potential is the most important dimension in target market selection. Legal, politics, infrastructure, economics are respectively ranked as influential dimensions. Culture dimension is reported ineffective in selecting Iranian electrical industry’s target markets.
Ali Akbar Akbar; Amir Salehipour
Volume 10, Issue 27 , January 2012, , Pages 144-166
Abstract
The earned value management is a powerful and important techniquein analyzing and controlling the project performance. While it allowsexact measurement of project progress, it lets corrective actions in atimely manner. In fact, the earned value allows project managers tofind out any project time and ...
Read More
The earned value management is a powerful and important techniquein analyzing and controlling the project performance. While it allowsexact measurement of project progress, it lets corrective actions in atimely manner. In fact, the earned value allows project managers tofind out any project time and cost deviations by calculating theperformance indices. In this paper, to improve the applicability of thetraditional earned value technique, we develop an integrated approachby combining statistical quality control charts with traditional earnedvalue technique, to monitor and control project time and costperformances. The results applied to a real construction projectcompete favorly against traditional approaches
Heirsh Soltanpanah; Hiwa Farughi; Rohoullah Abdi
Volume 10, Issue 26 , January 2012, , Pages 147-164
Abstract
Project cost estimation and actual time is one of the serious concernsof project managers. Earned Value Management is considered as atechnique for answering two following questions: how long does ittake to complete a project? How much does the project cost? ProjectPerformance Evaluation can only be predicated ...
Read More
Project cost estimation and actual time is one of the serious concernsof project managers. Earned Value Management is considered as atechnique for answering two following questions: how long does ittake to complete a project? How much does the project cost? ProjectPerformance Evaluation can only be predicated based on previousdata and knowledge in the present dealings of earned value and itsfuture conditions and prospects would not be categorically realized.Although there are many proposed methods to solve these boundaries,there is not a method encompassing all uncertainties and futureconditions. This paper aims at introducing a new method using timelimits, costs and project performance in fuzzy logic to determine theearned value indexes. Risk factors are added to the Fuzzy logics inorder to obtaining the precise estimation in predicting the finaloutcomes of the project. This paper provides a brief introductionregarding the current methods followed by investigation on Fuzzymethodology and risk factors. Finally, the offered model is proposed,defined and supported by means of an example
Laya Olfat; Farzaneh Khosravani; Reza Jalali
Volume 8, Issue 19 , December 2010, , Pages 147-163
Abstract
Risk is a potential which causes problems in the implementation of project and fulfillment of objectives. Risk is the innate part of all the projects and it is impossible to eliminate it completely though it can be managed effectively in order to reduce its effects on achieving the project’s objectives. ...
Read More
Risk is a potential which causes problems in the implementation of project and fulfillment of objectives. Risk is the innate part of all the projects and it is impossible to eliminate it completely though it can be managed effectively in order to reduce its effects on achieving the project’s objectives. It may occur in the future or not, but its occurrence at least affects one objective including area, time, costs or quality. Therefore identification, analysis and ranking of risk would play a significant role in the fulfillment of project. In this paper, we applied PMBOK Standard for identification of project risk for the construction of flyover junctions in Boushehr Province, and then we used Fuzzy AIIP Technique and Fuzzy TOPSIS Technique for ranking of risk.
Amir Abbas Yazdani; Yasser Fallah Makrani; Ramzan Gholami
Volume 8, Issue 20 , March 2011, , Pages 147-166
Abstract
One of the most common problems, encountered in the quality of product industrial units, includes low level & high distribution of production quality specifications. The complexity of methods causes the manager not to be able to make the right decision for solving this problem. The Six Sigma methodology ...
Read More
One of the most common problems, encountered in the quality of product industrial units, includes low level & high distribution of production quality specifications. The complexity of methods causes the manager not to be able to make the right decision for solving this problem. The Six Sigma methodology is a powerful tool for adjusting the parameters of production processes & its optimization in order to make them competitive products. To be able to guide the quality changes of goods in the desirable direction, first we must become familiar with these changes & then we must recognize the reasons of their presence. In this regard, barcode system which has high capabilities in increasing the speed & precision of data transfer can help the organization to reach a desirable level of sigma. The present article has attempted to familiarize the readers with the definition of six sigma methodology & how to use the barcode system to improve the sigma level in a case study. The quality improvement of products which is a result of optimized management of sigma level has resulted in achieving desirable economical goals for the organization. These goals have been assessed in the conclusion section.
Behrooz Rezaei Manesh; Jafar Ahangaran
Volume 11, Issue 31 , January 2014, , Pages 150-127
Abstract
Iranian managers in public organizations are generally motivated to introduce suggestion schemes in their organizations, which is also supported by laws and regulations. However our knowledge of key success factors is limited in terms of quality and quantity of previous research efforts. To fill ...
Read More
Iranian managers in public organizations are generally motivated to introduce suggestion schemes in their organizations, which is also supported by laws and regulations. However our knowledge of key success factors is limited in terms of quality and quantity of previous research efforts. To fill the gap, this study adopting a survey methodology with a random sample of employees in public offices and organizations of Iran, investigated factors with a potential affect on the successful introduction of suggestion systems in the organizations. We were especially interested to investigate the role of organization mission (industrial vs. non-industrial), as the adoption of suggestion systems has been relatively in industrial organizations. Research results show that organization mission through intermediating variables such as leadership style, organizational culture, organizational structure and processes have indeed statistically meaningful effect on the success of suggestion systems. Based on the results of the research, a readiness assessment model is proposed and recommendations are made for application and further research. Key words:
Mohammad Javad Mohagheghnia; Kashi Mansoor; Alireza Daliri; Mohammad Donyaei
Volume 12, Issue 33 , July 2015, , Pages 151-181
Abstract
This paper investigates the presence of long memory in the Tehran stock market, using the ARFIMA, GPH, GSP and FIGARCH models. The data set consists of daily returns, and long memory tests are carried out both for the returns and volatilities of TEPIX series. Results of the GPH, GSP and ARFIMA models ...
Read More
This paper investigates the presence of long memory in the Tehran stock market, using the ARFIMA, GPH, GSP and FIGARCH models. The data set consists of daily returns, and long memory tests are carried out both for the returns and volatilities of TEPIX series. Results of the GPH, GSP and ARFIMA models indicate the existence of long memory in return series. Also, suggest that long memory dynamics in the returns and volatility might be modeled by using the ARFIMA–FIGARCH model. Furthermore, results of this model shoes the strong evidence of long memory, both in conditional mean and conditional variance. In addition, the assumption of non-normality is appropriate for capturing the asymmetry and tail fatness of estimated residuals. These findings suggest that the model based on the Gaussian normality assumption may be inappropriate for modeling the long memory property. Finally, it seems that the Tehran Stock Exchange (TSE) cannot be considered an efficient market in terms of the speed of information transmission. Hence, speculative earnings could be gained via predicting stock prices.
Mehdi Yazdani; Bahman Naderi
Abstract
In the scheduling problems, it is commonly assumed that processing times are fixed and known. In the literature of project scheduling emphasizes that the time of each activity/operation can be multi-mode and by assigning more resources, the activity time can be reduced. In these problems, in addition ...
Read More
In the scheduling problems, it is commonly assumed that processing times are fixed and known. In the literature of project scheduling emphasizes that the time of each activity/operation can be multi-mode and by assigning more resources, the activity time can be reduced. In these problems, in addition to activity scheduling, allocation of available limited resources to the activities should also be carried out. This assumption that processing time of activities is fixed is a weakness in scheduling literature. This paper develops the classic problem flow shop scheduling to multi-mode resource-cosntrainted flow shop scheduling problem. This paper discusses comprehensively about mathematical modeling. In this regard, two mixed integer linear programming models with two differnet concepts are presented. The first model is location-based model and the second is sequence-based. The performance of the models are evaluated by comparing their size and computational complexities. In the size complexity, the first model requires more variables but less constraints than second Model. In the computational complexity, the first model significantly outperforms than the second Model. Also, the first model, besides solving more problems as optimally, requires less time to solve than the second model
Hossein Khanaki; Mahdi Azizmohammadi; Masoud Vakili; Saeed Khan Mohammadian
Volume 11, Issue 30 , October 2014, , Pages 153-179
Abstract
AbstractIn this paper, the critical parameters of a method of welding with shieldinggas arc welding (GMAW) are discussed; this method is an important processin creating high quality metal permanent connections in various industries,including the automobile industry to improve the quality of stemdiameter ...
Read More
AbstractIn this paper, the critical parameters of a method of welding with shieldinggas arc welding (GMAW) are discussed; this method is an important processin creating high quality metal permanent connections in various industries,including the automobile industry to improve the quality of stemdiameter welding parameters. One of the most useful techniques for modelingand solving the problems is Response Surface Method. In this paper,considering five most important factors such as speed welder, torch anglewith the work piece, electrode diameter, wire speed, gas consumption ,andCO2 levels as input variables, can be controlled independently from thelevel of response, the relationship between the input variables and the responsevariables were determined using linear regression. Then optimumvalue for each factor was calculated using non-linear programming model to evaluate the results obtained along with the comparison of output of theSimulation Annealing Algorithm.In this study, both qualitative and quantitative variables are considered toevaluate and optimize all response variables regarding that these variablesare not the same, and then fuzzy set theory and LP metric are used to findanswers for multi-objective optimization methods.
Mir Ali Seyyed Naghavi; Hamid Reza Qasemi
Volume 5, Issue 14 , December 2006, , Pages 153-177
Abstract
Human resource management, like every scientific issue other, faces some new approaches that gain from contingents of business environment. There has been a perspective since founding up the human resource management major that has been believed to design job in ...
Read More
Human resource management, like every scientific issue other, faces some new approaches that gain from contingents of business environment. There has been a perspective since founding up the human resource management major that has been believed to design job in organization then adapting people into that job. But, current conditions of organizations and increasing important of human resource as a knowledge capital is changing this perspective. The new perspective believes each firm needs to a certain human capital whom has strategic value-creating and high uniqueness, and in this state, human resource management of firm should adapts to the human capital. Mechanism of transit organization from traditional job-based perspective to new knowledge-based perspective called human resource architecture (HRA). In this paper, it is review on theoretical bases of HRA, and offers a model for designing HRA in organizations. The model has six dimensions including drivers, base elements, human resource system, human resource practices, people behavior, and HRA products.
M.J. Tarokh; K. Sharifiyan
Volume 6, Issue 17 , September 2007, , Pages 153-181
Abstract
Financial corporation and banks are sort of organization that due to specialty of their work, are very needy to customer management process ; and data mining is one of the best available tools for them to asses definition and behavior forecast of their customers.
Data mining is improving very fast and ...
Read More
Financial corporation and banks are sort of organization that due to specialty of their work, are very needy to customer management process ; and data mining is one of the best available tools for them to asses definition and behavior forecast of their customers.
Data mining is improving very fast and due to presence of vide range of data using computer is essential. Nets & powerful algorithms are used to emplace of manual analysis to derive knowledge & information from data.
In this paper: “Mellat Bank” and its information bank of different division has been evaluated after data extraction from information bank and noise distortion , k means algorithm and fuzzy - k - means algorithm standard test of cluster's compression were used for customer clustering in groups. Determination of optimum number of clusters is done by applying cluster quality assay function. Afterward was used to determine the quality of gained clusters. Then the value of each cluster was determined through FRM model. At the end of project for clusters analysis and define appropriate strategy for each cluster; the pyramid of customer value was used.
Alireza Alinezhad
Abstract
In the last decade, despite the extra importance of service and its increasing development in global and national economies, it has received less attention in comparison with manufacturing industries. The evaluation of performance in service organizations has always been one of the main challenges in ...
Read More
In the last decade, despite the extra importance of service and its increasing development in global and national economies, it has received less attention in comparison with manufacturing industries. The evaluation of performance in service organizations has always been one of the main challenges in this area. Parasuraman and colleagues’ five dimensional model is one of the most common models to evaluate the quality of service and was used in this paper to evaluate the service quality in CNG stations in Zanjan Province. In this paper, the Data Envelopment Analysis (DEA) was also used to assess the relative service quality in 36 CNG stations in Zanjan province. Due to the high importance of service quality, it was considered as the functional output of CNG Refueling Stations. The number of employees, number of dispensers, fixed monthly cost, and monthly allocated credit to stations were considered as functional inputs of CNG stations. After obtaining the station’s rank, finally, the sensitivity of results was analyzed using the proposed method of Jahanshahlu and colleagues. Also, the results showed that the developed model of multi criteria data envelopment analysis has better performance than basic models.
Maryam Azizi; Abolfazl Kazemi; Alireza Alinezhad
Abstract
Reverse logistics as a new approach and attitude in the area of logistics is one of the new trends in logistics management, recycling, and or reuse of products. Logistics network design in the forward and reverse mode is one of the most important issues that forms the strategic dimension of supply chain ...
Read More
Reverse logistics as a new approach and attitude in the area of logistics is one of the new trends in logistics management, recycling, and or reuse of products. Logistics network design in the forward and reverse mode is one of the most important issues that forms the strategic dimension of supply chain design. In this paper we propose a mixed integer linear programming (MILP) model for reverse logistics problem. In the proposed model costs of facilities construction, transportation and procurement from suppliers are minimized and importance of suppliers are maximized. Since the proposed model is NP-hard, we use NSGA-II and NRGA algorithms to solve the problem.
Tahereh Zaefarian; Mohammad Andabili; Hossein Momeni; Seyed Esmaeil Najafi
Abstract
Today, there are more than 300 types of cars in Iran auto market, which has a significant growth in recent decade. High variety have challenges for decision makers in selecting cars. No mathematical model has been developed yet for segmenting and ranking Iran auto market, which carry out both defining ...
Read More
Today, there are more than 300 types of cars in Iran auto market, which has a significant growth in recent decade. High variety have challenges for decision makers in selecting cars. No mathematical model has been developed yet for segmenting and ranking Iran auto market, which carry out both defining automatic cluster numbers as well as automatic weighting criteria by the model.This research develops a Hybrid DEMATEL-Two-Step Clustering-TOPSIS approach. The model first finds the beat appropriated criterion for segmentation. Then uses a two-step clustering approach for segmenting Iran auto market based on price criterion. Second, the criteria will be weighted automatically using Shannon entropy weighting method and then, TOPSIS method rank competitors in each defined price segment (lower 900 Million Rials). Also, the Spearman's rank correlation test is used to compare the model results with Iranian customer behavior (with selling volume). The price segmentation results reveal that the Iran auto market can be segmented in six different levels. Furthermore, the ranking results disclose that price is not the only effective factor in finding car utility for the buyer. A weighted combination of performance, features and price will determine optimized selection for buyers
Mostafa Ekhtiari
Volume 9, Issue 25 , July 2012, , Pages 161-179
Abstract
Now days, many internal banks of country experiment a kind of creditrisk, where can enumerate increasing non-performing loans of thebanks and not repayment problem of the central bank debts as itsresults. Therefore, to establish a system of credit risk management isnecessary and essential. The Five Cs ...
Read More
Now days, many internal banks of country experiment a kind of creditrisk, where can enumerate increasing non-performing loans of thebanks and not repayment problem of the central bank debts as itsresults. Therefore, to establish a system of credit risk management isnecessary and essential. The Five Cs of credit valid system is one ofthe rating systems of customers where can be considered for creditrisk management. In the other hand, existence of a suitable tool toestablish this system is necessary. The VIKOR method is one theefficient tools to rate feasible alternatives where can be used for ratingcredit of customers. In this paper, a method of advanced VIKOR willbe proposed which can present the optimal values of attributespreference weights in decision making process. To illustrate themethod proposed, a numerical example will be presented about creditrating problem of banks customers and the best feasible alternative togive facilities will be determined
