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This article deals with the vehicle routing problem with time
windows (VRPTW). This problem consists in determining a least-cost
set of trips to serve customers during specific time windows. The
proposed solution method is a memetic algorithm (MA), a genetic
algorithm hybridised with a local search. Contrary to most papers
on the VRPTW, which minimize first the number of vehicles, our
method is also able to minimize the total distance travelled. The
results on 56 classical instances are compared...
AMS Subj. Classification: 90C27, 05C85, 90C59The topic is related to solving the generalized vertex cover problem (GVCP) by genetic
algorithm. The problem is NP-hard as a generalization of well-known vertex cover problem
which was one of the first problems shown to be NP-hard. The definition of the GVCP and
basics of genetic algorithms are described. Details of genetic algorithm and numerical results
are presented in [8]. Genetic algorithm obtained high quality solutions in a short period of
time.
This paper presents a new approach to sensor placement based on diagnosability criteria. It is based on the study of structural matrices. Properties of structural matrices regarding detectability, discriminability and diagnosability are established in order to be used by sensor placement methods. The proposed approach manages any number of constraints modelled by linear or nonlinear equations and it does not require the design of analytical redundancy relations. Assuming that a constraint models...
A decision situation with partial information on preferences by means of a vector value function is assumed. The concept of minimum value dispersion solution as a reference point joined with a pseudodistance function from such a point and a dispersion level ε, lead to the notion of ε-dispersion set. The dispersion level represents the amount of value that the decision maker can be indifferent to, therefore he should choose his most preferred solution in this set. Convergence properties, as well...
In this paper the low autocorrelation binary sequence problem (LABSP) is modeled as a mixed integer quadratic programming (MIQP)
problem and proof of the model’s validity is given. Since the MIQP model is semidefinite, general optimization solvers can be used, and converge in a finite number of iterations. The experimental results show that IQP solvers, based on this MIQP formulation, are capable of optimally solving general/skew-symmetric LABSP instances of up to 30/51 elements in a moderate time....
This paper deals with the so called grouping problem which arises in telecommunication network optimization when transmission equipment with a certain hierarchy is used. It is shown how this problem is embedded in the complete scheme of network optimization and a general combinatorial model is developed to derive afterwards a solution procedure. The implementation of this procedure forms part of a software tool for the complete problem of transmission network planning. Some results deriving from...
In multi-expert multi-criteria decision making problems, we often have to deal with different opinions, different importance of criteria and experts, missing data, unexpressed opinions and experts who are not fully confident with their judgment. All these factors make the problem more difficult to solve, and run the risk of making the model logic less transparent. In this paper, we present a model based on simple assumptions described by logical rules, in order to maintain the model transparency...
In this note, we present a slight modification of an algorithm for the strict feasibility problem. This modification reduces the number of iterations.
In this note, we present a slight modification of an algorithm for the
strict feasibility problem. This modification reduces
the number of iterations.
Our aim is to adapt Fletcher's filter approach to solve optimal control problems for systems described by nonlinear Partial Differential Equations (PDEs) with state constraints. To this end, we propose a number of modifications of the filter approach, which are well suited for our purposes. Then, we discuss possible ways of cooperation between the filter method and a PDE solver, and one of them is selected and tested.
A modification of the limited-memory variable metric BNS method for large scale unconstrained optimization of the differentiable function is considered, which consists in corrections (based on the idea of conjugate directions) of difference vectors for better satisfaction of the previous quasi-Newton conditions. In comparison with [11], more previous iterations can be utilized here.
For quadratic objective functions, the improvement of convergence is the best
one in some sense, all stored corrected...
We propose a modified standard embedding for solving the linear complementarity problem (LCP). This embedding is a special one-parametric optimization problem . Under the conditions (A3) (the Mangasarian–Fromovitz Constraint Qualification is satisfied for the feasible set depending on the parameter ), (A4) ( is Jongen–Jonker– Twilt regular) and two technical assumptions, (A1) and (A2), there exists a path in the set of stationary points connecting the chosen starting point for with a certain...
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