Chain event graphs are a model family particularly suited for asymmetric causal discrete domains. This paper describes a dynamic programming algorithm for exact learning of chain event graphs from multivariate data. While the exact algorithm is slow, it allows reasonably fast approximations and provides clues for implementing more scalable heuristic algorithms.

We report a new optimal resolution for the statistical stratification problem under proportional sampling allocation among strata. Consider a finite population of N units, a random sample of n units selected from this population and a number L of strata. Thus, we have to define which units belong to each stratum so as to minimize the variance of a total estimator for one desired variable of int...

We give a comprehensive theoretical treatment for calculating the viewshed of a given point, present an analytical solution to the viewshed problem and a new algorithm for finding the viewshed on a triangulated terrain. We implement our algorithm on a real terrain. Some algorithms make use of the horizon information of the terrain to calculate viewshed. The vertices of the horizon of the terrai...

We show an alternative way of represent­ ing a Bayesian belief network by sensitivities and probability distributions. This represen­ tation is equivalent to the traditional rep­ resentation by conditional probabilities, but makes dependencies between nodes apparent and intuitively easy to understand. We also propose a QR matrix representation for the sensitivities and/ or conditional probabili...

The generalized list T -coloring is a common generalization of many graph coloring models, including classical coloring, L(p, q)-labeling, channel assignment and T -coloring. Every vertex from the input graph has a list of permitted labels. Moreover, every edge has a set of forbidden differences. We ask for such a labeling of vertices of the input graph with natural numbers, in which every vert...

In this work we study the Capacitated p-Center Problem (CpCP ) and we propose an exact algorithm to solve it. We study two auxiliary problems and their relation to CpCP , and we propose two different Lagrangean duals based on each of the auxiliary problems. The lower and upper bounds provided by each of the Lagrangean duals reduce notably the set of candidate radii and allow to solve the proble...

It is shown that the MAX2SAT problem is NP-complete even if every variable appears in at most three clauses. However, if every variable appears in at most two clauses, it is shown that it (and even the general MAXSAT problem) can be solved in linear time. When every variable appears in at most three clauses, we give an exact algorithm for MAXSAT that takes at most O(3 n=2 n) steps where n is th...

We consider the problem of assigning transmission powers to the nodes of a wireless network in such a way that all the nodes of the network are connected by bidirectional links and the total power consumption is minimized. A new exact algorithm, based on a new integer programming model, is described in this paper together with a new preprocessing technique.

We have developed an exact model and algorithm for the delay-constrained minimum cost loop problem (DC-MCLP) of finding broadcast loops from a source node. While the traditional minimum cost loop problem (MCLP) deals with only the traffic capacity constraint served by a port of source node, the DC-MCLP deals with the mean network delay and traffic capacity constraints simultaneously. The DC-MCL...

In this paper we present a survey of results concerning algorithms, complexity, and applications of the maximum clique problem. We discuss enumerative and exact algorithms, heuristics, and a variety of other proposed methods. An up to date bibliography on the maximum clique and related problems is also provided.