This paper presents a method of designing variable structure control systems for robots. As the on-board robot computational resources are limited, but in some cases the demands imposed on the robot by the user are virtually limitless, the solution is to produce a variable structure system. The task dependent part has to be exchanged, however the task governs the activities of the robot. Thus not only exchange of some task-dependent modules is required, but also supervisory responsibilities have to be switched. Such control systems are necessary in the case of robot companions, where the owner of the robot may demand from it to

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Data warehouses (DW), based on the multidimensional modeling, provide companies with huge historical information for the decision making process. As these DW's are crucial for companies in making decisions, their quality is absolutely critical. One of the main issues that influences their quality lays on the models (conceptual, logical and physical) we use to design them. In the last years, there have been several approaches to design DW's from the conceptual, logical and physical perspectives. However, from our point of view, there is a lack of more objective indicators (metrics) to guide the designer in accomplishing an outstanding model that allows us to guarantee the quality of these DW's. In this paper, we present a set of metrics to measure the quality of conceptual models for DW's. We have validated them through an empirical experiment performed by expert designers in DW's. Our experiment showed us that several of the proposed metrics seems to be practical indicators of the quality of conceptual models for DW's.

Hop.js is a multitier programming environment for JavaScript. It allows a single JavaScript program to describe the client-side and the server-side components of a web application. Its runtime environment ensures consistent executions of the application on the server and on the client.This paper overviews the Hop.js design. It shows the JavaScript extensions that makes it possible to conceive web applications globally. It presents how Hop.js interacts with the outside world. It also briefly presents the Hop.js implementation. It presents the Hop.js web server implementation, the handling of server-side parallelism, and the JavaScript and HTML compilers.