Railway Scheduling is considered to be a difficult and time-consuming task. Despite real railway networks being modelled as Constraint Satisfaction Problems (CSPs), they require a huge number of variables and constraints. The general CSP is known to be NP-complete; however, distributed models may reduce the exponential complexity by dividing the problem into a set of subproblems. In this work, ...

Temporal Action Logic is a well established logical formalism for reasoning about action and change using an explicit time representation that makes it suitable for applications that involve complex temporal reasoning. We take advantage of constraint satisfaction technology to facilitate such reasoning through temporal constraint networks. Extensions are introduced that make generation of actio...

A globally consistent labeling is a compact representation of the complete solution space for a constraint satisfaction problem (CSP). Constraint satisfaction is NP-complete and so is the construction of globally consistent labelings for general problems. However, for binary constraints , it is known that when constraints are convex, path-consistency is suucient to ensure global consistency and...

The study of tractable classes is an important issue in Artificial Intelligence, especially in Constraint Satisfaction Problems. In this context, the Broken Triangle Property (BTP) is a state-of-the-art microstructure-based tractable class which generalizes well-known and previously-defined tractable classes, notably the set of instances whose constraint graph is a tree. In this paper, we propo...

In the past few years there have been several empirical discoveries of phase transitions in constraint satisfaction problems (CSPs), and a growth of interest in the area among the arti cial intelligence community. This paper extends a simple analytical theory of phase transitions in three-satis ability (3-SAT) problems in two directions. First, a more accurate, problem-dependent calculation lea...

Generalised Satisfiability Problems (or Boolean Constraint Satisfaction Problems), introduced by Schaefer in 1978, are a general class of problem which allow the systematic study of the complexity of satisfiability problems with different types of constraints. In 1979, Valiant introduced the complexity class parity P, the problem of counting the number of solutions to NP problems modulo two. Ot...

Consider a population consisting of n individuals, each of whom has one of d types (e.g. their blood type, in which case d = 4). We are allowed to query this database by specifying a subset of the population, and in response we observe a noiseless histogram (a d-dimensional vector of counts) of types of the pooled individuals. This measurement model arises in practical situations such as poolin...

We consider the problems of finding the lexicographically minimal (or maximal) satisfying assignment of propositional formulas for different restricted classes of formulas. It turns out that for each class from our framework, these problems are either polynomial time solvable or complete for OptP. We also consider the problem of deciding if in the optimal assignment the largest variable gets va...

In this paper, we study the possibility of designing non-trivial random CSP models by exploiting the intrinsic connection between structures and typical-case hardness. We show that constraint consistency, a notion that has been developed to improve the efficiency of CSP algorithms, is in fact the key to the design of random CSP models that have interesting phase transition behavior and guarante...

A product line is a set of products and features with constraints on which subsets are available. Numerous configurators have been made available by product line vendors on the internet, in which procurers can experiment with the different options, e.g. how the selection of one product or feature entails or precludes the selection of another product or feature. We explore an approach to configu...