Abstract
Multi-view registration is an essential step in order to generate the side information for multi-view Distributed Video Coding. As stated in our previous work (Ciobanu and Crte-Real, Multimed Tools Appl 48(3):411-436, 2010) it can be achieved by SIFT (scale-invariant feature transform) generated keypoint matches. The registration accuracy is vital for the adequate generation of side information and it directly depends on the reliable match of possibly all the available point to point correlations between two complete-overlapped views. We propose a solution to this problem based on iterative filtering of SIFT-generated keypoint matches, using the Hough transform and block matching. It aims the generic, real-life and constraint-free scenarios having an arbitrarily close angle between the two views. Practical results show an overall significant reduction of the outliers while maintaining a high rate of correct matches.

Abstract
We experimentally demonstrate the accuracy of an all-optical S-R latch and an optical S-R flip-flop based on hybrid integrated Mach-Zehnder Interferometers, with Semiconductor Optical Amplifier in each arm (MZI-SOA). The performance of both bistable devices will be studied and compared in terms of extinction ratio and switching times. © 2011 IEEE.

Abstract

Abstract
The construction industry has been the sector that reports a higher incidence of fatal accidents all over the world. Several studies have been conducted in order to address the causes of higher rates of accidents in this sector. These studies point out, among other factors, the occurrence of trips and slips in obstacles and structures as major causal factors for the occurrence of falls. In spite of the enormous amount of tasks, in the construction process, involving manual material handling of loads and its negative effect on postural balance and risk perception, the contribution of these tasks for the occurrence of falls, in the construction industry, is scarce. This paper presents a laboratory simulation study of the contribution of manual material handling tasks for the occurrence of falls through the analysis of the force required to preserve postural balance during obstacle clearance. A sample of eight construction workers participated on this study, which were attached, by an harness, to a load cell in order to analyse the force exerted during the performance of each trial. The results showed an increase of the applied force when the task was performed with the handling of a load

Abstract
It is increasingly common to find research on the usability of E-learning systems. From the results of these investigations, it seems clear that most of them point to the need for a critical discussion about usability evaluation methods for specific education systems, particularly on the importance of methods focus on the primary users. However, it also seems to be urgent and essential to investigate how ergonomic analysis has been applied, as well as the necessary adaptations to such usability analysis methods, in order to set up assessments which are more consistent with the nature of the systems. It is now known that, in general terms, users go through several stages of interaction with the system throughout the period of tasks execution. In each of these interaction phases, their behavior and actions can lead them to success, or failure, with regard to compliance with the pre-set goals. Many of the commonly used usability evaluation methods do not stop to analyze the interactions occurring in the context of use. This paper presents a critical review of usability evalution for E-learning systems.

Abstract
The correct grading of free text answers to exam questions during an assessment process is time consuming and subject to fluctuations in the application of evaluation criteria, particularly when the number of answers is high (in the hundreds). In consequence of these fluctuations, inherent to human nature, and largely determined by emotional factors difficult to mitigate, it is natural that small discrepancies arise in the ratings assigned to similar responses. This means that two answers with similar quality may get a different grade which may generate inequities in the assessment process. Reducing the time required by the assessment process on one hand, and grouping the answers in homogenous groups, on the other hand, are the main motivations for developing the work presented here. We believe that it is possible to reduce unintentional inequities during an assessment process of free text answers by applying text mining techniques, in particular, automatic text classification, enabling to group answers in homogeneous sets comprising answers with uniform quality. Thus, instead of grading answers in random order, the teacher may assess similar answers in sequence, one after the other. The teacher may also choose, for example, to grade free text answers in decreasing order of quality, the best first, or in ascending order of quality, starting to grade the group of the worst answers. The active learning techniques we are applying throughout the grading process generate intermediary models to automatically organize the answers still not fixed in homogeneous groups. These techniques contribute to reduce the time required for the assessment process, to reduce the occurrence of grading errors and improve detection of plagiarism. © Academic Publishing International Ltd.