This paper describes a visual cryptography method for the elimination of pixel expansion and the improvement of contrast. The proposed method uses the probability concept to construct a multiobjectivelinear programmi...
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This paper describes a visual cryptography method for the elimination of pixel expansion and the improvement of contrast. The proposed method uses the probability concept to construct a multiobjective linear programming model for general access structures. Then, the solution space of the model is explored by goal programming. The advantages of the proposed method are fourfold. First, it can avoid expanding the shadow images. Second, it can reach better contrast. Third, it can deal with general access structures and get the desired contrast levels. Fourth, it can be easily extended to deal with the problems of multiple secret images. Experiments on several access structures show that the proposed method is effective against pixel expansion and is capable of contrast improvement. (c) 2006 Society of Photo-Optical Instrumentation Engineers.
In this paper, by considering the experts' imprecise or fuzzy understanding of the nature of the parameters in the problem-formulation process, large-scale multiobjective block-angular linearprogramming problems ...
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In this paper, by considering the experts' imprecise or fuzzy understanding of the nature of the parameters in the problem-formulation process, large-scale multiobjective block-angular linearprogramming problems involving fuzzy numbers are formulated. Through the use of the alpha-level sets of fuzzy numbers, an extended Pareto optimality concept, called the alpha-Pareto optimality is introduced. To generate a candidate for the satisficing solution which is also alpha-Pareto optimal, decision maker is asked to specify the degree alpha and the reference objective values. It is shown that the corresponding alpha-Pareto optimal solution can be easily obtained by solving the minimax problems for which the Dantzig-Wolfe decomposition method is applicable. Then a linearprogramming-based interactive decision-making method for deriving a satisficing solution for the decision maker efficiently from an alpha-Pareto optimal solution set is presented. (C) 1997 Elsevier Science B.V.
This paper deals with a class of biobjective mixed binary linear programs having a multiple-choice constraint, which are found in applications such as Pareto set-reduction problems, single-supplier selection, and inve...
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This paper deals with a class of biobjective mixed binary linear programs having a multiple-choice constraint, which are found in applications such as Pareto set-reduction problems, single-supplier selection, and investment decisions, among others. Two objective space-search algorithms are presented. The first algorithm, termed line search and linearprogramming filtering, is a two-phase procedure. Phase 1 searches for supported Pareto outcomes using the parametric weighted sum method, and Phase 2 searches for unsupported Pareto outcomes by solving a sequence of auxiliary mixed binary linear programs. An effective linearprogramming filtering procedure excludes arty previous outcomes found to be dominated. The second algorithm, termed linearprogramming decomposition and filtering, decomposes the mixed binary problem by iteratively fixing binary variables and uses the linearprogramming filtering procedure to prune out any dominated outcomes. Computational experiments show the effectiveness of the linearprogramming filtering and suggest that both algorithms run faster than existing general-purpose objective space-search procedures.
This paper considers multiobjective linear programming problems (MOLPP) where random fuzzy variables are contained in objective functions and constraints. A new decision making model optimizing possibilistic value at ...
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This paper considers multiobjective linear programming problems (MOLPP) where random fuzzy variables are contained in objective functions and constraints. A new decision making model optimizing possibilistic value at risk (pVaR) is proposed by incorporating the concept of value at risk (VaR) into possibility theory. It is shown that the original MOLPPs involving random fuzzy variables are transformed into deterministic problems. An interactive algorithm is presented to derive a satisficing solution for a decision maker (DM) from among a set of Pareto optimal solutions. Each Pareto optimal solution that is a candidate of the satisficing solution is exactly obtained by using convex programming techniques. A simple numerical example is provided to show the applicability of the proposed methodology to real-world problems with multiple objectives in uncertain environments. (C) 2012 Elsevier Ltd. All rights reserved.
In this paper, we propose ct fuzzy satisficing method for the solution of multiobjectivelinear continuous optimal control problems. To solve these multiobjectivelinear continuous optimal control problems, we first d...
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In this paper, we propose ct fuzzy satisficing method for the solution of multiobjectivelinear continuous optimal control problems. To solve these multiobjectivelinear continuous optimal control problems, we first discretize the time and replace the system of differential equations by difference equations. By introducing suitable auxiliary variables, approximate linearmultiobjectiveprogramming problems are formulated. Then by considering the vague nature of human judgements, we assume that the decision maker may have fuzzy goals for the objective functions. Having elicited the corresponding linear membership functions through the interaction with the decision maker, if we adopt the fuzzy decision for combining them, it is shown that the formulated problem can be reduced to a linearprogramming problem and the satisficing solution for the decision maker can be obtained through the simplex method of linearprogramming. An Illustrative numerical example is provided to indicate the efficiency of the proposed method.
This paper describes the use of flexibility analysis with uncertain parameters involved in linear models. Due to the presence of various judgments of value in large-scale systems, the previous formulation developed un...
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This paper describes the use of flexibility analysis with uncertain parameters involved in linear models. Due to the presence of various judgments of value in large-scale systems, the previous formulation developed under single-objective optimization is revised by use of the minimum aspiration level, which plays an important role in multiobjective optimization. An improved algorithm to compute the flexibility index in an iterative manner is also presented. The proposed approach is applied to a post-optimal analysis of the dynamic allocation planning of an electric power system. Such consideration is shown to be of special importance in increasing reliability at the planning stage of problem-solving in uncertain systems.
The geometric duality theory of Heyde and Lohne (2006) defines a dual to a multiple objective linear programme (MOLP). In objective space, the primal problem can be solved by Benson's outer approximation method (B...
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The geometric duality theory of Heyde and Lohne (2006) defines a dual to a multiple objective linear programme (MOLP). In objective space, the primal problem can be solved by Benson's outer approximation method (Benson 1998a,b) while the dual problem can be solved by a dual variant of Benson's algorithm (Ehrgott et al. 2007). Duality theory then assures that it is possible to find the (weakly) nondominated set of the primal MOLP by solving its dual. In this paper, we propose an algorithm to solve the dual MOLP approximately but within specified tolerance. This approximate solution set can be used to calculate an approximation of the weakly nondominated set of the primal. We show that this set is a weakly E-nondominated set of the original primal MOLP and provide numerical evidence that this approach can be faster than solving the primal MOLP approximately.
In this paper a new method for generating the set of efficient extreme-points for the three-objective linearprogramming problem is presented. This method successfully exploits the fact that vectors that are strictly ...
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In this paper a new method for generating the set of efficient extreme-points for the three-objective linearprogramming problem is presented. This method successfully exploits the fact that vectors that are strictly efficient in associated multi-objective problems of lower dimensions are also efficient in the full multi-objective problem.
We propose a modelling framework which allows considering different priorities and individual expansion and contraction scales for distinct types of inputs and outputs, through the Weighted Russell Directional Distanc...
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We propose a modelling framework which allows considering different priorities and individual expansion and contraction scales for distinct types of inputs and outputs, through the Weighted Russell Directional Distance Model (WRDDM). An equivalence model between the WRDDM and the super-ideal point model has also been established, which is then incorporated into several interactive multiobjective linear programming (MOLP) approaches. The use of these diverse interactive methodologies allows obtaining the benchmark Decision Making Units (DMUs) which best suit the decision maker's (DM) preferences. This feature can be useful since traditional Data Envelopment Analysis (DEA) models tend to completely neglect the DM's preferences and value judgements in the computation of the DMUs used as a reference of best practices. Therefore, with this tool the DMs have the possibility of translating into the decision-making process management constraints (namely, budgetary) and aspiration levels regarding the inputs and outputs, providing much more realistic support for actual decision-making.
Global optimization problems with a quasi-concave objective function and linear constraints are studied. We point out that various other classes of global optimization problems can be expressed in this way. We present...
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Global optimization problems with a quasi-concave objective function and linear constraints are studied. We point out that various other classes of global optimization problems can be expressed in this way. We present two algorithms, which can be seen as slight modifications of Benson-type algorithms for multiple objective linear programs (MOLP). The modification of the MOLP algorithms results in a more efficient treatment of the studied optimization problems. This paper generalizes results of Schulz and Mittal (Math Program 141(1-2): 103-120, 2013) on quasi-concave problems and Shao and Ehrgott (Optimization 65(2): 415-431, 2016) on multiplicative linear programs. Furthermore, it improves results of Lohne and Wagner (J Glob Optim 69(2): 369-385, 2017) on minimizing the difference f = g-h of two convex functions g, h where either g or h is polyhedral. Numerical examples are given and the results are compared with the global optimization software BARON.
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