Abstract
Programming contests should be capable of being appealing to both the contestants and the general public. We feel that the use of graphical user interfaces and computer graphics could help achieve this goal, providing new ways of viewing the task. We describe experiments we made with games (Tic-Tac-Toe, Snake and Ataxx, an Othello-like game), which were made available to students with graphical components, and discuss the results. We also present a simple graphic library where simple drawings can be made and show how it can be used in a programming contest environment. We then conclude by revisiting some past IOI problems, suggesting ways to enhance them with graphical components.

Abstract
A novel Mach-Zehnder interferometer based on a fibre multimode interference structure combined with a long period fibre grating is proposed. The multimode interference is achieved through the use of a multimode fibre section splices between two sin-le-mode fibres, with a length adjusted to couple a fraction of light into the cladding modes. A LP placed after the multimode fibre couples light back into the fibre core completing the Mach-Zehnder interferometer. The novel configuration was demonstrated as a bending sensor.

Abstract
This paper presents the mathematical models and the solution algorithms of DC optimal power flow problems: considering uncertainties represented by fuzzy numbers affecting loads as well as the elements of the cost function. The main purpose of this work corresponds to transfer the uncertainties affecting both the loads and the cost vector to the results that one usually obtain with such a DC optimal power flow model, that is, to characterize the uncertainties that affect the generations, the voltage phases, the branch flows. Apart from that, this paper also describes the algorithm to be used to calculate the uncertainties affecting the nodal marginal prices, since these prices are related with the dual variables of several constraints in the optimization problem. The developed algorithms are based in the solution of multiparametric problems in which one considers parameters both in the right hand side vector of the constraints (in order to represent load uncertainties) and in the cost function (to consider uncertainties in fuel costs, for instance). Finally, the paper includes a results of a Case Study designed to illustrate the application of the developed algorithms as well as results obtained for the IEEE 24 bus test system.

Abstract
Relations between fabrication conditions and optical characteristics of planar waveguides made by proton exchange in benzoic acid are documented in the literature, but reports on the characterization of waveguide fabrication processes, performed in a systematic way, could not be found, resulting in the need to combine data from several authors. Discrepancies among results from different researches are evident, resulting from different experimental methodologies and calibration of equipment. Therefore, aiming at extracting a consistent data set, optical characterization of the refractive index profile was employed to study series of samples. The objective was to develop a methodology for fabrication of proton-exchanged channel waveguides in LiNbO3 operating in the single-mode regime at several wavelengths, with specific characteristics required to optimize integrated devices. To achieve this, it is necessary to obtain the relations between the optical characteristics of the waveguides and their fabrication conditions, and to introduce models of the waveguide formation process. (c) 2007 Society of Photo-Optical Instrumentation Engineers.

Abstract
This paper describes a fully complete autonomous hybrid robot system, named YAM (Yet Another Mouse), that is able to navigate through an unknown maze environment. YAM effectively tackles the problem of how to represent the environment using its sensor data to produce probability maps of the walls and beacons. Besides that, it is capable of computing long-term path plans using an adapted breadth-first search algorithm. It also shows how it is possible to model the actual motors behavior as a reactive task, using artificially created virtual short-term goals. We give real contest results, showing how YAM behaved on the "CiberRato" robotics competition.

Abstract
In this paper we derive a set of approximate but general bilinear Kalman filter equations for a multiinput multi-output bilinear stochastic system driven by general autocorrelated inputs. The derivation is based on a convergent Picard sequence of linear stochastic state-space subsystems. We also derive necessary and sufficient conditions for a steady-state solution to exist. Provided all the eigenvalues of a chain of structured matrices are inside the unit circle, the approximate bilinear Kalman filter equations converge to a stationary value. When the input is a zero-mean white noise process, the approximate bilinear Kalman filter equations coincide with those of the well known bilinear Kalman filter model operating under white noise inputs.