The alldifferent Constraint: A Survey

The constraint of difference is known to the constraint programming community since Lauriere introduced Alice in 1978. Since then, several solving strategies have been designed for this constraint. In this paper we give both a practical overview and an abstract comparison of these different strategies.Comment: 12 pages, 3 figures, paper accepted at the 6th Annual workshop of the ERCIM Working Group on Constraint

Decomposition Based Search - A theoretical and experimental evaluation

In this paper we present and evaluate a search strategy called Decomposition Based Search (DBS) which is based on two steps: subproblem generation and subproblem solution. The generation of subproblems is done through value ranking and domain splitting. Subdomains are explored so as to generate, according to the heuristic chosen, promising subproblems first. We show that two well known search strategies, Limited Discrepancy Search (LDS) and Iterative Broadening (IB), can be seen as special cases of DBS. First we present a tuning of DBS that visits the same search nodes as IB, but avoids restarts. Then we compare both theoretically and computationally DBS and LDS using the same heuristic. We prove that DBS has a higher probability of being successful than LDS on a comparable number of nodes, under realistic assumptions. Experiments on a constraint satisfaction problem and an optimization problem show that DBS is indeed very effective if compared to LDS.Comment: 16 pages, 8 figures. LIA Technical Report LIA00203, University of Bologna, 200

Management of content development and subject engagement through an arts matrix model: A case study

From 2007 - 2009, Kansas State University Libraries (K-State Libraries) committed to strategically assess and redevelop their organizational structure. The Libraries’ Strategic Plan and position redistributions commenced in 2007 and 2009 respectively, with adjustments in 2010 to accommodate the university’s “K-State 2025” Strategic Plan. Together, these plans changed the roles of former subject librarians, dividing and transferring responsibilities for outreach, reference, instruction, and collection development. Among the more significant changes was the creation of departments devoted to patron groups, rather than specific academic disciplines. Illustrating how the reorganization changed the roles of traditional library services, this chapter will outline the responsibilities of three librarian positions: Undergraduate and Community Services, Faculty and Graduate Services, and Content (collection) Development. The librarians are also founding members of the K-State Libraries Arts Matrix, an ad hoc team operating within the new organization to enhance communication and expand subject expertise in the visual and performing arts. These transitions presented both opportunities for engagement and specialization, and challenges to communication and subject identity. These issues are addressed, including solutions offered by the matrix model. Although this study is limited by the neoteric existence of this model, and lack of precedents for comparison, K-State Libraries’ example may offer a viable model for institutions adapting to fiscal realities. Additionally, matrices may supplement the traditional subject librarian model for those seeking to enhance engagement and collaboration. This chapter offers further insight into a strategic planning process, as well as a transparent, inclusive strategy for librarians adjusting to organizational change

Device for doubling the frequency of a light wave comprising a non-linear optical compound

The invention relates to a nonlinear optical medium and a device comprising such a nonlinear optical medium which can be suitably used to double the frequency of red light, while forming blue light. The nonlinear optical medium comprises a polymer matrix and nonlinear optical compounds which contain a substituted sulphone group as the electron-acceptor group

Conjunctions of Among Constraints

Many existing global constraints can be encoded as a conjunction of among constraints. An among constraint holds if the number of the variables in its scope whose value belongs to a prespecified set, which we call its range, is within some given bounds. It is known that domain filtering algorithms can benefit from reasoning about the interaction of among constraints so that values can be filtered out taking into consideration several among constraints simultaneously. The present pa- per embarks into a systematic investigation on the circumstances under which it is possible to obtain efficient and complete domain filtering algorithms for conjunctions of among constraints. We start by observing that restrictions on both the scope and the range of the among constraints are necessary to obtain meaningful results. Then, we derive a domain flow-based filtering algorithm and present several applications. In particular, it is shown that the algorithm unifies and generalizes several previous existing results.Comment: 15 pages plus appendi

Nonlinear optical compound, nonlinear optical medium, method of manufacturing a nonlinear optical medium and device for doubling the frequency of a light wave

The invention relates to a nonlinear optical medium and a device comprising such a nonlinear optical medium which can be suitably used to double the frequency of red light, while forming blue light. The nonlinear optical medium comprises a polymer matrix and nonlinear optical compounds which contain a substituted sulphone group as the electron-acceptor group