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Search Results: 1 - 10 of 12841 matches for " Mohammad Izadikhah "
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Context-Dependent Data Envelopment Analysis with Interval Data  [PDF]
Mohammad Izadikhah
American Journal of Computational Mathematics (AJCM) , 2011, DOI: 10.4236/ajcm.2011.14031
Abstract: Data envelopment analysis (DEA) is a non-parametric method for evaluating the relative efficiency of decision making units (DMUs) on the basis of multiple inputs and outputs. The context-dependent DEA is introduced to measure the relative attractiveness of a particular DMU when compared to others. In real-world situation, because of incomplete or non-obtainable information, the data (Input and Output) are often not so deterministic, therefore they usually are imprecise data such as interval data, hence the DEA models becomes a nonlinear programming problem and is called imprecise DEA (IDEA). In this paper the context-dependent DEA models for DMUs with interval data is extended. First, we consider each DMU (which has interval data) as two DMUs (which have exact data) and then, by solving some DEA models, we can find intervals for attractiveness degree of those DMUs. Finally, some numerical experiment is used to illustrate the proposed approach at the end of paper.
Group Decision Making Process for Supplier Selection with TOPSIS Method under Interval-Valued Intuitionistic Fuzzy Numbers
Mohammad Izadikhah
Advances in Fuzzy Systems , 2012, DOI: 10.1155/2012/407942
Abstract: Supplier selection is a fundamental issue of supply chain area that heavily contributes to the overall supply chain performance, and, also, it is a hard problem since supplier selection is typically a multicriteria group decision problem. In many practical situations, there usually exists incomplete and uncertain, and the decision makers cannot easily express their judgments on the candidates with exact and crisp values. Therefore, in this paper an extended technique for order preference by similarity to ideal solution (TOPSIS) method for group decision making with Atanassov's interval-valued intuitionistic fuzzy numbers is proposed to solve the supplier selection problem under incomplete and uncertain information environment. In other researches in this area, the weights of each decision maker and in many of them the weights of criteria are predetermined, but these weights have been calculated in this paper by using the decision matrix of each decision maker. Also, the normalized Hamming distance is proposed to calculate the distance between Atanassov's interval-valued intuitionistic fuzzy numbers. Finally, a numerical example for supplier selection is given to clarify the main results developed in this paper. 1. Introduction Supplier selection, the process of finding the right suppliers who are able to provide the buyer with the right quality products and/or services at the right price, at the right time, and in the right quantities, is one of the most critical activities for establishing an effective supply chain. Selecting the wrong supplier could be enough to deteriorate the whole supply chains financial and operational position. In todays highly competitive, global operating environment, it is impossible to produce low-cost, high-quality products successfully without satisfactory suppliers [1, 2]. The success of a supply chain is highly dependent on selection of good suppliers. Supplier selection is a fundamental issue of supply chain area that heavily contributes to the overall supply chain performance. Particularly for companies that spend a high percentage of their sales revenue on parts and material supplies and whose material costs represent a larger portion of total costs, savings from supplies are of particular importance. These strongly urge for a more systematic and transparent approach to purchasing decision making, especially regarding the area of supplier selection. Selecting the suppliers significantly reduces the purchasing cost and improves corporate competitiveness, and that is why many experts believe that the supplier selection
Deriving Weights of Criteria from Inconsistent Fuzzy Comparison Matrices by Using the Nearest Weighted Interval Approximation
Mohammad Izadikhah
Advances in Operations Research , 2012, DOI: 10.1155/2012/574710
Abstract: Deriving the weights of criteria from the pairwise comparison matrix with fuzzy elements is investigated. In the proposed method we first convert each element of the fuzzy comparison matrix into the nearest weighted interval approximation one. Then by using the goal programming method we derive the weights of criteria. The presented method is able to find weights of fuzzy pairwise comparison matrices in any form. We compare the results of the presented method with some of the existing methods. The approach is illustrated by some numerical examples. 1. Introduction Weight estimation technique in multiple criteria decision making (MADM) problem has been extensively applied in many areas such as selection, evaluation, planning and development, decision making, and forecasting [1]. The conventional MADM requires exact judgments. In the process of multiple criteria decision making, a decision maker sometimes uses a fuzzy preference relation to express his/her uncertain preference information due to the complexity and uncertainty of real-life decision making problem and the time pressure, lack of knowledge, and the decision maker’s limited expertise about problem domain. The priority weights derived from a fuzzy preference relation can also be used as the weights of criteria or used to rank the given alternatives. Xu and Da [2] utilized the fuzzy preference relation to rank a collection of interval numbers. Fan et al. [3] studied the multiple attribute decision-making problem in which the decision maker provides his/her preference information over alternatives with fuzzy preference relation. They first established an optimization model to derive the attribute weights and then to select the most desirable alternative(s). Xu and Da [4] developed an approach to improving consistency of fuzzy preference relation and gave a practical iterative algorithm to derive a modified fuzzy preference relation with acceptable consistency. Xu and Da [5] proposed a least deviation method to obtain a priority vector from a fuzzy preference relation. Determining criteria weights is a central problem in MCDM. Weights are used to express the relative importance of criteria in MCDM. When the decision maker is unable to rank the alternatives holistically and directly with respect to a criterion, pairwise comparisons are often used as intermediate decision support. In the other words, in evaluating competing alternatives under a given criterion, it is natural to use the framework of pairwise comparisons represented by a square matrix from which a set of preference values for the
A goal programming method for deriving fuzzy priorities of criteria from inconsistent fuzzy comparison matrices
Mohammad Izadikhah
Management Science Letters , 2012,
Abstract: Decision making problem is the process of finding the best option from all of the feasible alternatives. One of the most important concepts in decision making process is to identify the weights of criteria. In real-world situation, because of incomplete or non-obtainable information, the data (attributes) are often not deterministic and can be treated in forms of fuzzy numbers. This paper investigates a method for deriving the weights of criteria from the pair-wise comparison matrix with fuzzy elements. Finding the weights of criteria has been one of the most important issues in the field of decision-making and the present method uses goal programming to solve the resulted model. In addition, using a ranking function we convert each obtained fuzzy weight to a crisp one, which makes it possible to compare the criteria. The proposed model of this paper is supported by several examples and a case study.
Evaluation of decision making units in the presence of fuzzy and non-discretionary
N. Fathi,M. Izadikhah
Applied Mathematical Sciences , 2013,
Abstract: In original data envelopment analysis (DEA) models, input and output aremeasured by exact values on a ratio scale. However, this assumption may not bealways valid. For example some data may be only known as in forms of fuzzy andnon–discretionary data. In this paper we try to suggest a generalized model whensome inputs and outputs are fuzzy and non-discretionary data.
An Interactive Procedure to Solve Multi-Objective Decision-Making Problem: An Improvment to STEM Method
R. Roostaee,M. Izadikhah,F. Hosseinzadeh Lotfi
Journal of Applied Mathematics , 2012, DOI: 10.1155/2012/324712
Abstract: Decisions in the real-world contexts are often made in the presence of multiple, conflicting, and incommensurate criteria. Multiobjective programming methods such as multiple objective linear programming (MOLP) are techniques used to solve such multiple-criteria decision-making (MCDM) problems. One of the first interactive procedures to solve MOLP is STEM method. In this paper we try to improve STEM method in a way that we search a point in reduced feasible region whose criterion vector is closest to positive ideal criterion vector and furthest to negative ideal criterion vector. Therefore the presented method tries to increase the rate of satisfactoriness of the obtained solution. Finally, a numerical example for illustration of the new method is given to clarify the main results developed in this paper.
Exploring the Catalytic Activity of Zirconia, Zirconia Supported Metals and Metal Oxides for Oxidation of Phenol  [PDF]
Mohammad Sadiq, Mohammad Ilyas
Modern Research in Catalysis (MRC) , 2012, DOI: 10.4236/mrc.2012.12004
Abstract: Catalytic oxidation/degradation of phenol with molecular oxygen in aqueous medium by Zirconia, zirconia supported metals and metal oxides at low temperature were studied in a three necked batch reactor. The catalysts prepared were characterized by modern techniques like XRD, SEM and EDX. The activities of different catalysts for the oxidation of phenol in aqueous medium were found to be in the order; Pt-Pd/ZrO2 > Bi-Pt/ZrO2 > Bi-Pd/ZrO2> Pt/ZrO2 > Pd/ZrO2 > Cu/ZrO2> Mn/ZrO2 > Bi/ZrO2. The enhanced catalytic activity of Bi-Pt/ZrO2 is attributed to Bi which in contact with Pt particles promotes its catalytic activity. In short, catalytic oxidation was found to be an effective tool, for the removal of phenol, from industrial waste water.
Glanular Anterior Urethral Valve; A Case Report of an Unusual Cause of Neonatal Urinary Retention  [PDF]
Mohammad Aminu Mohammad
Open Journal of Pediatrics (OJPed) , 2016, DOI: 10.4236/ojped.2016.62025
Abstract: Anterior urethral valve is an uncommon abnormality whose etiology is uncertain, unlike in the case of posterior urethral valve. Glanular anterior urethral valve is even rarer. We present an unusual case of anterior urethral valve, which presented with acute urinary retention and was successfully managed with excision and glans reconstruction. A history of poor stream and dribbling, recurrent urinary tract infections and palpable penile or peno-scrotal mass strongly points to the diagnosis of anterior urethral valve. A voiding cystourethrogramme confirms the diagnosis. It can cause early proximal urinary tract damage and renal failure if not intervened in time. Early surgical intervention will prevent the onset of uremia. Transurethral resection is the treatment of choice.
Pectin-Based Biodegradable Hydrogels with Potential Biomedical Applications as Drug Delivery Systems  [PDF]
Mohammad Sadeghi
Journal of Biomaterials and Nanobiotechnology (JBNB) , 2011, DOI: 10.4236/jbnb.2011.21005
Abstract: In this work, synthesis and swelling behavior of a superabsorbent hydrogel based on Pectin (Pc) and polyacrylonitrile (PAN) were investigated. A mechanism for hydrogel formation was proposed and the structure of the product was es-tablished using FTIR spectroscopy. The Pc-poly (sodium acrylate-co-acrylamide) hydrogel exhibited a pH-responsive swelling-deswelling behavior at pH’s 2 and 8. This on-off switching behavior provides the hydrogel with the potential to control delivery of bioactive agents. Release profiles of ibuprofen (IBU), a poor water-soluble drug, from the hydro-gels were studied under both simulated gastric and intestinal pH conditions.
Multilayer Hex-Cells: A New Class of Hex-Cell Interconnection Networks for Massively Parallel Systems  [PDF]
Mohammad Qatawneh
Int'l J. of Communications, Network and System Sciences (IJCNS) , 2011, DOI: 10.4236/ijcns.2011.411086
Abstract: Scalability is an important issue in the design of interconnection networks for massively parallel systems. In this paper a scalable class of interconnection network of Hex-Cell for massively parallel systems is introduced. It is called Multilayer Hex-Cell (MLH). A node addressing scheme and routing algorithm are also presented and discussed. An interesting feature of the proposed MLH is that it maintains a constant network degree regardless of the increase in the network size degree which facilitates modularity in building blocks of scalable systems. The new addressing node scheme makes the proposed routing algorithm simple and efficient in terms of that it needs a minimum number of calculations to reach the destination node. Moreover, the diameter of the proposed MLH is less than Hex-Cell network.
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