The paper examines the applicability of mathematical programming methods to the simultaneous optimization of the structure and the operational parameters of a combined-cycle-based cogeneration plant. The optimization problem is formulated as a non-convex mixed-integer nonlinear problem (MINLP) and solved by the MINLP solver LaGO. The algorithm generates a convex relaxation of the MINLP and appl...

We study a generalization of the vertex packing problem having both binary and bounded continuous variables, called the mixed vertex packing problem (MVPP). The wellknown vertex packing model arises as a subproblem or relaxation of many 0-1 integer problems, whereas the mixed vertex packing model arises as a natural counterpart of vertex packing in the context of mixed 0-1 integer programming. ...

We study the polyhedral structure of a new model for various bottleneck resource allocation problems in which the resource consumption is determined by the activity with the maximum usage. The model, called the mixed vertex packing problem, is a generalization of the vertex packing problem having both binary and bounded continuous variables. We give valid inequalities and separation algorithms ...

The Degree/diameter problem asks for the largest graphs given diameter and maximum degree. This problem has been extensively studied both for directed and undirected graphs, ando also for special classes of graphs. In this work we present the state of art of the degree/diameter problem for mixed graphs. c © 2015 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Org...

We develop a technique using dual mixed-volumes to study the isotropic constants of some classes of spaces. In particular, we recover, strengthen and generalize results of Ball and Junge concerning the isotropic constants of subspaces and quotients of Lp and related spaces. An extension of these results to negative values of p is also obtained, using generalized intersection-bodies. In particul...

The mixed Chinese postman problem is a version of the well-known Chinese postman problem in which the underlying graph consists of both directed and undirected edges. We give an integer linear programming formulation for this problem and then show that the extreme points of its linear relaxation polyhedron are all half-integral. keywords: Chinese postman problem, half-integrality, graph, flow

Suszko’s problem is the problem of finding the minimal number of truth values needed to semantically characterize a syntactic consequence relation. Suszko proved that every Tarskian consequence relation can be characterized using only two truth values. Malinowski showed that this number can equal three if some of Tarski’s structural constraints are relaxed. By so doing, Malinowski introduced a ...

In this paper, we introduce a novel artificial neural network to solve the portfolio optimization problem. The proposed neural network is called the Mixed Tabu Machine since its structure is similar to the Tabu Machine, but includes both discrete and continues variables. Similar to the Hopfield network, the state of the Mixed Tabu Machine is updated to find the global minimum energy state. To e...

The general mixed problem has been shown to be NP hard, so that the exact solution of the general problem is computationally intractable, except for small problems. In this paper we consider not the general problem, but a particular special case of this problem, the rank one mixed problem. We show that for this case the mixed problem is equivalent to its upper bound (which is convex), and it ca...

You must either save a group of m people or a group of n people. If there are no morally relevant diff erences among the people, which group should you save? Th is problem is known as the number problem. Th e recent discussion has focussed on three proposals: (i) Save the greatest number of people, (ii) Toss a fair coin, or (iii) Set up a weighted lottery, in which the probability of saving m p...