COMBINATORIAL choice models are based on the implicit assumption that decision-makers consider all possible combinations that can be made by the options in a given set. Therefore, these models assumed that the chosen combination is the most preferable combination. However, decision-makers may not consider all possible combinations due to the limited attention. Thus, the chosen combination is not necessarily the best. This paper presents a model that can explain such choice behaviors. After presenting the model, we investigate its revealed preference implications and explain how one can make inferences about individuals’,preferences considering their choices in the new context. Finally, for the model to be testable, we present its characterizing axiom and show that it is equivalent to the model.

In this paper, we consider statistics on permutations of lengthn represented geometrically as bargraphs having the same number of horizontal steps. More precisely, we nd the joint distribution of the descent and up step statistics on the bargraph representations, thereby obtaining a new rened count of permutations of a given length. To do so, we consider the distribution of the parameters on permutations of a more general multiset of which Sn is a subset. In addition to nding an explicit formula for the joint distribution on this multiset, we provide counts for the total number of descents and up steps of all its members, supplying both algebraic and COMBINATORIAL proofs. Finally, we derive explicit expressions for the sign balance of these statistics, from which the comparable results on permutations follow as special cases.

This article is intended to be a survey on some COMBINATORIAL topics in group theory. The bibliography at the end is neither claimed to be exhaustive, nor is it necessarily connected with a reference in the text. I include it as I see it revolves around the concepts which are discussed in the text.

In this paper we provide explicit formulas for the number of elements/subgroups/cyclic subgroups of a given order and for the total number of subgroups/cyclic subgroups in a finite Hamiltonian group. The coverings with three proper subgroups and the principal series of such a group are also counted. Finally, we give a complete description of the lattice of characteristic subgroups of a finite Hamiltonian group.

Today, the quality of measurement data is more important than ever. It depends on the statistical characteristics of repeated measurements performed under stable conditions in a measurement system. In other words, the quality of the measurement system is of particular importance because it can even overshadow the uctuations of the production process. If the quality of the measurement system and the resulting sampling gures are low, the process analysis will not be valid and the correct decision cannot be made to increase the quality. In this respect, the Multi-Attribute Decision Making (MADM) technique can be used to make proper decision along with using the new and hybrid method of analysis and guidance systems. One of the basic principles of any organization is to ensure that the data are obtained from measuring its products. If the quality of the measurement system is poor and, as a result, the quality of the resulting data is poor, the analysis of the process will not be valid and there may be incorrect decisions about whether or not to accept it and the costs involved will obviously be high. Numerous models have been developed to support decision-making processes over the years. As one of the research areas of operations research and management, Multi-Criteria Decision Making (MCDM) can be a solution for evaluating and ranking options from the best to the worst. The worst-case conditions under con icting criteria with regard to decision-making priorities should be found. Decision-making is one of the key tasks of management. Comparison of dierent measurement systems can also be very helpful in selecting the contractor to reduce the risk of production or decisionmaking. For this purpose, various MCDM methods in the analysis of measurement systems have been used. The method of this research is descriptive-library type such that by developing basic models collected from articles and reference books, we present a new model and select the best option using MADM technique. These indices were obtained by CRITIC method and then, the options were ranked using fuzzy summing method.

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This paper proposes an efficient and novel method for transmission expansion planning in regulated environment of power systems. The method is based on combination of two algorithms such as special genetic algorithm (GA) and constructive heuristic algorithm. The proposed GA has its own special characteristics that make it better than other metahuristic methods in transmission expansion planning problems. The improvement phase is the main characteristic that makes this type of GA more efficient. It means that if after mating procedure (selection, crossover and mutation), the offspring was an infeasible one, by using a suitable constructive heuristic algorithm, and the aforementioned offspring is changed to a feasible one. Also by using a relaxed linear model of TEP and importing cost perturbation, a qualified initial population is obtained and used as an initial population of GA. The simulation results obtained from the proposed method were compared to those achieved from previous literature in terms of solution quality and computational efficiency. Results reveal that the superiority of this method in both aspects of financial and CPU time.

The IT value measurement model proposed to evaluate the business value of IT. This model utilizes some different tools and techniques such as: Benchmarking, Balanced Scorecard, qualitative and quantitative measurement techniques. The basis of this model is a link between 3- layer IT classification and IT planning with a COMBINATORIAL approach. Connecting these three layers with effectiveness and efficiency concepts led this model from a conceptual to a practical framework various effects of different IT levels on the organization performance were analyzed by using secondary data. In each layer a balanced scorecard framework was setup and some measures were selected in each zone; and then compared with the historical trends, reference values which carried out by benchmarking and relative' cost ratios. The outcome will show deviations and weame's Spoints of IT planning and activities which should be studied by creative problem solving techniques in order to find roots of the problems, the last step of a typical IT value measurement program is planning and running an improvement project. This study will propose a framework to measure IT value both before and after planning and implementation.