Abstract
Nesting problems are particularly hard combinatorial problems. They involve the positioning of a set of small arbitrarily-shaped pieces on a large stretch of material, without overlapping them. The problem constraints are bidimensional in nature and have to be imposed on each pair of pieces. This all-to-all pattern results in a quadratic number of constraints. Constraint programming has been proven applicable to this category of problems, particularly in what concerns exploring them to optimality. But it is not easy to get effective propagation of the bidimensional constraints represented via finite-domain variables. It is also not easy to achieve incrementality in the search for an improved solution: an available bound on the solution is not effective until very late in the positioning process. In the sequel of work on positioning non-convex polygonal pieces using a CLP model, this work is aimed at improving the expressiveness of constraints for this kind of problems and the effectiveness of their resolution using global constraints. A global constraint "outside" for the non-overlapping constraints at the core of nesting problems has been developed using the constraint programming interface provided by Sicstus Prolog. The global constraint has been applied together with a specialized backtracking mechanism to the resolution of instances of the problem where optimization by Integer Programming techniques is not considered viable. The use of a global constraint for nesting problems is also regarded as a first step in the direction of integrating Integer Programming techniques within a Constraint Programming model.

Abstract

Abstract
The commercial use of the Internet for service provision has deeply changed the environment where human-computer interaction takes place, as Web interfaces are now integrated in multi-platform service provision. This paper presents the results of a study of a multi-channel Portuguese bank, making use of both Marketing and HCI methods and concepts, to understand customer usage of the different service platforms. The study involved in-depth interviews, focus groups, a web survey and a telephone survey with bank customers. The study allowed the identification of the most important interaction experience requirements for this multi-platform service, and how they are influenced by user profiles and service characteristics. The results also show that Customer Experience Requirements (CERs) have a strong impact on customer choice and usage of the different service platforms and can be better captured with Essential Use Cases (EUCs), as they are technology independent. Designing a multi-platform service interaction should therefore start with a higher level of abstraction that allows a multi-platform, customer experience and essential use case perspectives. With this integrated approach, the Internet service can therefore be designed in order to best leverage its capabilities and its complementarity with the other service platforms.

Abstract
This paper addresses the problem of interaction design for service provision to customers in a multi-platform environment. It is based on a qualitative and quantitative study of a Portuguese multi-channel retail bank, and shows that, as most of the financial operations are functionally available across the different service platforms, experience requirements become increasingly influential in customers' usage of the different channels. Different financial services generate different interaction needs, and the fit between experience requirements and channel performance in satisfying those needs has a strong impact on customer channel choices. Based on these findings, essential use cases are applied and extended to capture experience requirements for the different financial operations in a technology independent way. With this approach, interaction designers can identify which platforms are best suited to provide the different services available, improving the multi-channel service as a whole. On the other hand, it also enables the identification of areas of interaction experience that need improvement in each platform, if services offered are likely to be effectively used.

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This paper presents the INFOVINI project that aims to be the leading portal for the wine industry in Portugal. The basic idea is simple, yet powerful: to have a single entry point for all the latest information on Portuguese wines. The site will build upon the experience gained from a previous project, e-Mercatura, and will be based in an open platform that will enhance the collaboration between organizations in the sector. The innovative approach lies not only in the completeness of the database, which will be unique in Portugal, but also in the platform built in order to assure automatic update of the information. The INFOVINI project represents an extremely important contribution to a new way of working, promoting collaborative processes across organizations, and projecting a new image of Portuguese wines in foreign markets.

Abstract
In this paper, we study the complexity of a data mining algorithm for extracting patterns from user web navigation data that was proposed in previous work.(3) The user web navigation sessions are inferred from log data and modeled as a Markov chain. The chain's higher probability trails correspond to the preferred trails on the web site. The algorithm implements a depth-first search that scans the Markov chain for the high probability trails. We show that the average behaviour of the algorithm is linear time in the number of web pages accessed.