Resumo em Inglês:

In 1923, Eduard Helly published his celebrated theorem, which originated the well known Helly property. Say that a family of subsets has the Helly property when every subfamily of it, formed by pairwise intersecting subsets, contains a common element. There are many generalizations of this property which are relevant to some parts of mathematics and several applications in computer science. In this work, we survey computational aspects of the Helly property. The main focus is algorithmic. That is, we describe algorithms for solving different problems arising from the basic Helly property. We also discuss the complexity of these problems, some of them leading to NP-hardness results.

Resumo em Inglês:

We present a novel method to reduce the effect of specularities in digital images. Our approach relies on a simple modification of the capture setup: a multi-flash camera is used to take multiple pictures of the scene, each one with a differently positioned light source. We then formulate the problem of specular highlights reduction as solving a Poisson equation on a gradient field obtained from the input images. The obtained specular reduced image is further refined in a matting process with the maximum composite of the input images. Experimental results are demonstrated on real and synthetic images. The entire setup can be conceivably packaged into a self-contained device, no larger than existing digital cameras.

Resumo em Inglês:

Aspect-oriented software development promotes improved separation of concerns by introducing a new modular unit, called aspect, for the modularization of crosscutting concerns. As a new kind of modular unit, aspects should have explicit interfaces that describe the way they interact with the rest of the system and how they affect other modules. This interaction can be homogeneous or heterogeneous. In this paper, we present crosscutting interfaces as a conceptual tool for dealing with the complexity of heterogeneous aspects at the design level. Crosscutting interfaces have been incorporated by the aSideML modeling language in order to enhance aspect description at the design level. Moreover, we present a modeling notation for the description of architecture-level aspects that also supports the explicit representation of crosscutting interfaces. Finally, we present two large-scale case studies we have performed using this modeling language that support our arguments in favor of crosscutting interfaces.

Resumo em Inglês:

With the growing dissemination and reliability of wireless networks and the emergence of devices with increasing processing and communication power, applications that up to now were restricted to the PCs are being envisaged to run on devices as heterogeneous as wrist clocks, refrigerators with access to the internet, mobile phones, PDAs, set-top-boxes, game consoles etc. Application development for this myriad of devices and networks with different capabilities requires special attention from the software programmers and designers -especially when these applications are shared among multiple users. Application adaptation, which allows a software to react to device and environment resource variations, is an important process to fit the application to a certain device configuration. A large amount of work has focused on the adaptation of multimedia such as text, images, audio and video. Less attention has been given to 3D media adaptation -firstly because of the complexity involved in the 3D application adaptation, and also because true marketing opportunities for 3D applications in heterogeneous devices have just began to emerge. This paper analyses 3D media adaptation as a nonfunctional requirement for 3D multiuser virtual environment applications. An adaptation framework is proposed that can be integrated to the MPEG-4 standard to offer a solution to the adaptation of 3D multiuser virtual environment applications, which can be accessed from heterogeneous devices with different capabilities. The advantages of integrating the framework to the MPEG-4 standard are twofold: it favors the creation of complex applications, with high degree of interaction, such as multiuser 3D collaborative environments; and makes easier to build these applications for heterogeneous devices (from cellular phones to PDAs and set-top-boxes) since MPEG-4 is aimed at small mobile devices and narrowband networks, such as some wireless networks.

Resumo em Inglês:

Infeasible paths constitute a bottleneck for the complete automation of software testing, one of the most expensive activities of software quality assurance. Research efforts have been spent on infeasible paths, basically on three main approaches: prediction, classification and identification of infeasibility. This work reports the results of experiments on data flow based criteria and of studies aimed at the three approaches above. Identification, classification, and prediction of infeasible paths are revisited in the context of data flow based criteria (Potential Uses Criteria-PU). Additionally, these aspects are also addressed in the scope of integration and object-oriented testing. Implementation aspects of mechanisms and facilities to deal with infeasibility are presented taking into consideration Poketool - a tool that supports the application of the Potential Uses Criteria Family. The results and ideas presented contribute to reduce the efforts spent during the testing activity concerning infeasible paths.