Background: There is lack of Iranian studies on marital satisfaction which is one of the important factors in the stability of marriage. The present study aimed to evaluate the effects of socio-demographic variables on marital satisfaction. Methods: This Analytical and  cross-sectional study was conducted on 770 married people from Gonabad city, Northeast of Iran. Simple random sampling was us...

This paper proposes a computational model for solving optimisation problems that mimics the principle of evolutionary transitions in individual complexity. More specifically it incorporates mechanisms for the emergence of increasingly complex individuals from the interaction of more simple ones. The biological principles for transition are outlined and mapped onto an evolutionary computation co...

In order to apply constraint programming to a particular domain, the problem must first be modelled as a constraint satisfaction problem. There are typically many alternative models of a given problem, and formulating an effective model requires a great deal of expertise. To reduce this bottleneck, the Essence language allows the specification of a problem abstractly, i.e. without making modell...

Product configuration systems are often based on a variability model. The development of a variability model is a time consuming and error-prone process. Considering the ongoing development of products, the variability model has to be adapted frequently. These changes often lead to mistakes, such that some products cannot be derived from the model anymore, that undesired products are derivable ...

We further generalise a construction – the fibre construction – that was developed in an earlier paper of the first two authors. The extension in this paper gives a polynomial-time reduction of CSP(H) for any relational system H to CSP(P ) for any relational system P that meets a certain technical partition condition, that of being K3-partitionable. Moreover, we define an equivalent condition o...

Model transformation is seen as a promising approach to automate software development and verification, thus improving quality and reducing production costs significantly. However, errors of transformation programs can propagate into the generated artifacts complicating the detection of errors. The current paper proposes a static type checking approach for early detection of typing errors of pa...

Solving constraint satisfaction problems (CSP) efficiently depends on the solver configuration and the search strategy. However, it is difficult to customize the constraint solvers because they are not modular enough, and it is hard to create new search strategies by composition. To solve these problems, we propose spacetime programming, a paradigm based on lattices and synchronous process calc...

A signed graph (G,Σ) is an undirected graph G together with an assignment of signs (positive or negative) to all its edges, where Σ denotes the set of negative edges. Two signatures are said to be equivalent if one can be obtained from the other by a sequence of resignings (i.e. switching the sign of all edges incident to a given vertex). Extending the notion of usual graph homomorphisms, homom...

For a digraph H, the Constraint Satisfaction Problem with template H, or CSP(H), is the problem of deciding whether a given input digraph G admits a homomorphism to H. The CSP dichotomy conjecture of Feder and Vardi states that for any digraph H, CSP(H) is either in P or NP-complete. Barto, Kozik, Maróti and Niven (Proc. Amer. Math. Soc, 2009) confirmed the conjecture for a class of oriented tr...

The Consistent Labeling Problem is of considerable importance in Artificial Intelligence, Operations Research and Symbolic Logic. It has received much attention, but most work has addressed the specialized binary form of the problem. Furthermore, none of the relatively few papers that treat the general problem have dealt analytically with the issue of complexity. In this paper we present two al...