Negin Mohebbi; Amir Abbas Najafi
Abstract
Portfolio selection has always been one of the important issues in the field of investment management, which discusses how to allocate an investor's capital to different assets and form an efficient portfolio. If the modeling assumptions for portfolio optimization is closer to the real world, the results ...
Read More
Portfolio selection has always been one of the important issues in the field of investment management, which discusses how to allocate an investor's capital to different assets and form an efficient portfolio. If the modeling assumptions for portfolio optimization is closer to the real world, the results will be more reliable. Considering single horizon for investment is not real and more investors are investing for more than one period to be able to revise their positions over time. Moreover, in the real world, data and parameters are always uncertain. Therefore, the development of multi-period portfolio optimization models is a basic requirement. In this paper, based on the portfolio theory, a new multi-period portfolio selection model is proposed, which contains transaction costs, liquidity constraints, threshold constraints, cardinality constraints and class constraints. Moreover, mean absolute deviation is used as a measure of risk and uncertainty of data is modeled with scenario tree. Also, in order to solve the proposed model, the dynamic programming method has been used and finally, the model efficiency was tested using data for 5 stocks from Tehran Stock Exchange in a period of 1390 to 1394. In the proposed model, the effect of some factors such as boundary of decision variables and the number of assets in the portfolio is examined. The results indicate that the proposed model has a suitable performance and completely consistent with the theory.
Reza Yousefi Zenouz; Reza Olamaie; Somayeh Olamaie
Abstract
Millions of people encounter coronary artery disease annually, and this disease constitutes a large number of patients. Although considerable progress has been made in medical science, but the early detection of this disease is still a challenging issue. The aim of this paper is to describe developing ...
Read More
Millions of people encounter coronary artery disease annually, and this disease constitutes a large number of patients. Although considerable progress has been made in medical science, but the early detection of this disease is still a challenging issue. The aim of this paper is to describe developing a fuzzy expert system that will help to detect CAD at an early stage. Rules were extracted with the aid of doctors and fuzzy approach was taken to cope with the present uncertainty in the medical domain. The results indicate a high level of correct detection of normal and abnormal groups of people. The suggested methodology can help the doctors in medical diagnosis
Gholamreza Jamali; Elham Karimi Asl
Abstract
Supply Chain Management (SCM) is considered as a key factor to achieve goals such as creating competitive advantage, product quality improvement and increasing profitability in the cement industry. The main purpose of this research is to determine competitive positioning for LARG supply chain in the ...
Read More
Supply Chain Management (SCM) is considered as a key factor to achieve goals such as creating competitive advantage, product quality improvement and increasing profitability in the cement industry. The main purpose of this research is to determine competitive positioning for LARG supply chain in the iranian cement industry and to do Importance-Performance Analysis (IPA) for its related strategic requirements (Strenghts, Weaknesses, Opportunities and Threats). A survey-descriptive research method was applied and an available sample includes 11 Iranian cement companies were selected. First, with reviewing related literature and using the Delphi Method (DM), the strategic requirements of LARG supply chain in the cement industry identified. In the next step, the importance of each strategic requirement determined using SWARA technique. Then the results of applying Internal/External Factors Evaluation (IFE/EFE) matrix showed that to achieve the suitable position in the LARG supply chain for the Iranian cement industry an aggressive strategy should be taken. In the final step, applying Importance-Performance Analysis (IPA) matrix showed all requirements for aggressive strategy except exporting opportunities and cooperation culture in the supply chain that were in quadrant one, evaluated in quadrant II (keep up the good work). Finally, some suggestions presented toward improving LARG supply chain performance in the Iranian cement industry.
Laya Olfat; Maghsoud Amiri; Ebrahim Teimoury; Fatemeh Ghasemzadeh Gevari
Abstract
In today’s competitive world, supply chain management gains more attention every day. One of the most challenging topics in this field for managers and researchers is supply chain disruption management. When a disruption occurs in an echelon of a multi level supply chain, it may affect other echelon’s ...
Read More
In today’s competitive world, supply chain management gains more attention every day. One of the most challenging topics in this field for managers and researchers is supply chain disruption management. When a disruption occurs in an echelon of a multi level supply chain, it may affect other echelon’s performance in that supply chain as well. The main objective of current research is helping decision makers to choose best supply, production and ordering quantity between echelons so that after disruption occurrence, SC recovers and returns to pre-disruption plan with minimum recovering costs.In this paper, production and retailers disruptions are studied and a mathematical recovery plan is designed with objective function of minimizing total cost of supply chain in the recovery period to help all members of the supply chain in returning to normal situation. The proposed model is solved in MATLAB 2011 by the suggested heuristic method as well as GAMS software. Finally, results of both solvers are compared which shows the applicability of heuristic method
Javad Behnamian; Zeinab Akhavan
Abstract
Work in industrial workshops and heavy activities has effects on the health of workers and in terms of occupational hazards associated with many risks for them. Since in the industrial units there are different works in terms of ergonomic load and hardship of work, the occupational hazards can be reduced ...
Read More
Work in industrial workshops and heavy activities has effects on the health of workers and in terms of occupational hazards associated with many risks for them. Since in the industrial units there are different works in terms of ergonomic load and hardship of work, the occupational hazards can be reduced by job rotation scheduling. In this paper, using reduction approach, the ergonomic job rotation scheduling problem (EJRP) is reduced to parallel machine scheduling problem so that its exact methods (such as branch and bound method) are used to solve the EJRP. Furthermore, according to the proposed reduction, the lower bounds for parallel machine scheduling problem also applied for branch and bound solving method. The main aim of this research is providing an optimal scheduling for job rotation by applying human factors engineering approach in order to minimize the maximum workload on the staffs
Abbas Shoul; Esmaeil Keshavarz
Abstract
In the present research, Time-Cost-Quality trade off problem is formulated and solved, from a new point of view. To this end, quality is defined as a function of time and cost, then by defining the project’s quality as minimum value of quality of activities and regarding predecessor relations between ...
Read More
In the present research, Time-Cost-Quality trade off problem is formulated and solved, from a new point of view. To this end, quality is defined as a function of time and cost, then by defining the project’s quality as minimum value of quality of activities and regarding predecessor relations between activities, a tri-objective programming model is formulated to trade off the time, cost and quality. In order to solve the problem, objective functions of time and cost described as fuzzy goals and a fuzzy decision-making methodology has been used to reformulate the proposed tri-objective model to a single-objective model. Producing a final solution, instead of a set of Pareto efficient solutions, is one of the advantages of proposed method, which prevents decision maker from confusion. In order to describe performance and show the potential applicability of proposed methodology, a time-cost-quality trade-off problem for a project with real data from Organization for Renovating, Developing and Equipping Schools of Kerman province is solved. Finally, in order to validate the proposed model and method, a parametric analysis, which systematically varies the main parameters of model, is employed.
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
Razieh Taghipour; Soroush Avakh Darestani
Abstract
In recent years, maintenance has been recognized as an effective and a significant improvement tool in the performance of equipments. Maintenance plays an important role in maintaining reliability, availability and quality of products, risk reduction, efficiency increase and safety, so maintenance and ...
Read More
In recent years, maintenance has been recognized as an effective and a significant improvement tool in the performance of equipments. Maintenance plays an important role in maintaining reliability, availability and quality of products, risk reduction, efficiency increase and safety, so maintenance and its strategies have a special place in the industry. A lot of researches show the necessity of using fuzzy sets in decision making problems due to its high flexibility. The choosing maintenance strategy is also a problem with so many uncertainties so using fuzzy sets seems to be very useful. The aim of this research is to provide a suitable mathematical decision making model for assessment and selection maintenance strategies by using hierarchical fuzzy Axiomatic Design (HFAD) and hierarchical fuzzy Topsis (HFTOPSIS) in Haft Almas Co. Since many criteria such as added value, safety, and … so are vital in the maintenance strategy selection, in this article first these criteria are investigated in the literature review and expert's opinions, then for obtaining the weights of criteria the FAHP method is used and finally the strategies are ranked through the applying HFAD and HFTOPSIS. The results of FTOPSIS and FAD were compared in selecting a maintenance strategy. The results of comparisons indicate the similarity of rankings by two techniques. Above techniques show that TPM alternative has superior to other strategies.
Azam Keshavarz Hadadha; Zahra Jalili Bal; Siamak Haji Yakhchali
Abstract
Project Portfolio Selection is one of the strategic decisions on the level of management in project-oriented organizations; which is one of the most important and effective stages in project portfolio management. In other words, after identification and evaluation of different projects, optimal combination ...
Read More
Project Portfolio Selection is one of the strategic decisions on the level of management in project-oriented organizations; which is one of the most important and effective stages in project portfolio management. In other words, after identification and evaluation of different projects, optimal combination of projects must be selected based on different criteria. Since commonly resources of organizations are less than required resources on projects that are ahead of the organization; so project selection among different project portfolio and decision making about these issues are inevitable in organizations. So durability of organizations depends closely on the way of modeling and used approaches for project selection problem. In previous researches related to project selection problem, generally the problem of project clustering have not deeply been considered while project clustering may allow that projects to reach the highest return. In this article, we will propose a model for clustering, evaluating and selecting projects. At first projects will be clustered in various portfolios by K-MEANS algorithm, then projects of each portfolio will be evaluated and prioritized with analytical network process (ANP). Finally, projects from each portfolio will be selected based on knapsack problem
Mahdi Bastan; Elaheh Abbasi; Alimohammad Ahamadvand; Reza Ramazani K
Abstract
Acceptance of new technology and developed products is one of the main interest of innovative organization’s managers. Service organizations create value for their customers through the development of new products and services and can earn profit from this. New products development lead to high ...
Read More
Acceptance of new technology and developed products is one of the main interest of innovative organization’s managers. Service organizations create value for their customers through the development of new products and services and can earn profit from this. New products development lead to high R&D costs, and if the new products and services are not accepted by target customers, the expected profit will not be achieved. The purpose of the present research is to provide a deep insight about effective factors for mobile banks’ acceptance. Mobile-bank is an e-banking channel with the ability to earn income and profit as well as reduce the cost of operation for banks. So, understanding the effective factors as well as the dynamics in the process of acceptance and diffusion it by customers has importance for managers of banks. In this research, after reviewing the related literature about technology acceptance, and identifying the variables affecting the acceptance of mobile banking, a system dynamics model was presented which by representing the causal structure and simulation model, can analyze the dynamics of the acceptance process. The results of implementing the four scenarios were simulated and analyzed. The results show that the improvement of effective factors on the intention to use of customers is more effective than other policies, such as promotion advertising and development of new services and feature in the current mobile bank
