Abstract
Regular expressions are being used in many applications to specify multiple and complex text patterns in a compact way. In some of these applications large sets of regular expressions need to be evaluated to detect matched content. Specialised hardware engines are employed when software-based regular expression engines are not able to meet the performance requirements imposed by such applications. Since the sets of regular expressions are periodically modified and/or extended, FPGAs are an attractive hardware solution to achieve both programmability and high-performance demands. However, efficient automatic synthesis tools are of paramount importance to achieve fast prototyping of regular expression engines on these devices. This paper presents an overview of the synthesis of regular expressions with the aim of achieving high-performance engines for FPGAs. We focus on describing current solutions, proposing new solutions for constraint repetitions and overlapped matching, and discussing a number of challenges and open issues. As a case study, we present FPGA implementations of the regular expressions included in two rule-sets of network intrusion detection system (NIDS), Bleeding Edge and Snort, obtained using a state-of-the-art synthesis approach.

Abstract
This paper describes a joint trajectory optimized controller for a humanoid robot simulator following the real robot characteristics. As simulation is a powerful tool for speeding up the control software development, the proposed accurate simulator allows to fulfill this goal. The simulator, based on the Open Dynamics Engine and GLScene graphics library, provides instant visual feedback. The proposed simulator, with realistic dynamics, allows to design and test behaviours and control strategies without access to the real hardware in order to carry out research on robot control without damaging the real robot in the early stages of the development. The joints controller techniques, such as acceleration, speed and energy consumption minimization are discussed and experimental results are presented in order to validate the proposed simulator.

Abstract
This paper is concerned with modeling and simulation of a wind energy system with different topologies for the power converters, namely a two-level converter and a multilevel converter. Pulse modulation by space vector modulation associated with sliding mode is used for controlling the converters, and power factor control is introduced at the output of the converters. Finally, a case study is presented, showing the electric behavior of the power and the current at the output of the converters and the direct voltage at the multilevel converter.

Abstract
There is a one-to-one correspondence between C 1+H Cantor exchange systems that are C 1+H fixed points of renormalization and C 1+H diffeomorphisms f on surfaces with a codimension 1 hyperbolic attractor ? that admit an invariant measure absolutely continuous with respect to the Hausdorff measure on ?. However, there is no such C 1+a Cantor exchange system with bounded geometry that is a C 1+a fixed point of renormalization with regularity a greater than the Hausdorff dimension of its invariant Cantor set. The proof of the last result uses that the stable holonomies of a codimension 1 hyperbolic attractor ? are not C 1+? for ? greater than the Hausdorff dimension of the stable leaves of f intersected with ?. © 2007, Birkhäuser Verlag Basel/Switzerland.

Abstract
Expeditious modelling of virtual urban environments consists of generating realistic 3d models from limited information. It has several practical applications but typically suffers from a lack of accuracy in the parameter values that feed the modeller. By gathering small amounts of information about certain key urban areas, it becomes possible to feed a system that automatically compares and adjusts the input parameter values to find optimal solutions of parameter combinations that resemble the real life model. These correctly parameterized rules can then be reapplied to generate virtual models of real areas with similar characteristics to the referenced area. Based on several nature inspired metaheuristic algorithms such as genetic algorithms, simulated annealing and harmony search, this paper presents a new hybrid metaheuristic algorithm capable of optimizing functions with both discrete and continuous parameters and offer competitive results in a highly neglected field of application.

Abstract
Of all the detrimental effects of spinal cord injury (SCI), one of the most devastating effects is the disruption of the ability to walk. Therefore, much effort has been focused on developing several methods to document the recovery of locomotor function after experimental SCI. Computerized rat gait analysis is becoming increasingly popular in the SCI research community. The two-dimensional (2D) kinematic approach is by far the most popular technique in rat gait analysis. This is a simple inexpensive procedure, which requires only one camera to record the movement. Our study included an examination of locomotion on a treadmill using 2D and three-dimensional (3D) analysis, in neurologically intact animals and following moderate T9 contusion injury. Despite the overall time course patterns of the curves were identical, we found significant differences between values of the 2D and 3D joint angular motion. In conclusion, maximal precision and accuracy of the kinematic values are expected when the experimental protocol includes a 3D motion analysis methodology. Moreover, a 2D method cannot be used to determine the external or internal rotations of the foot because this movement occurs in the transverse plane.