Abstract
The importance of entrepreneurship education from elementary school through college is now recognized as an important aspect of children's education. At the level of basic education, the development of entrepreneurial activities using Information and Communication Technologies, specifically three-dimensional virtual worlds, is seen as an area with potential for exploration. The research presented herein is a model that allows the development of entrepreneurial activities in virtual worlds with children attending primary education. This model allows the preparation, monitoring and development of entrepreneurship education activities in virtual worlds, including safe interaction in virtual worlds between the children and the community. For this, we identified a set of requirements that would allow the teaching and learning of entrepreneurship in virtual worlds, from which a technological model was implemented through an application, EMVKids (after the Portuguese expression "Empreendedorismo em Mundos Virtuais com Criancas", entrepreneurship with children in virtual worlds).

Abstract
This paper presents a Pattern Based Testing approach for testing security aspects of the applications under test (AUT). It describes the two security patterns which are the focus of this work (“Account Lockout” and “Authentication Enforcer”) and the test strategies implemented to check if the applications are vulnerable or not regarding these patterns. The PBST (Pattern Based Security Testing) overall approach has two phases: exploration (to identify the web pages of the application under test) and testing (to execute the test strategies developed in order to detect vulnerabilities). An experiment is presented to validate the approach over five public web applications. The goal is to assess the behavior of the tool when varying the upper limit of pages to visit and assess its capacity to find real vulnerabilities. The results are promising. Indeed, it was possible to check that the vulnerabilities detected corresponded to real security problems. Copyright

Abstract
In this paper, the local control structure of amicrogrid is partiallymodified by a Lyapunov-based controller. This controller is derived based on direct Lyapunov stability theory (DLST) in order to calculate proper switching functions for the stable operation of the local controller as well as proper local performance of each inverter-based distributed generation (DG) unit. The main contribution is the use of DLST-based controller in a hierarchical primary control structure along with a DC-side voltage regulator. A current-based droop controller is also introduced along with a voltage harmonic compensation technique. The control limits of droop equations are calculated based on steady-state and dynamic capability curve as well as voltage-frequency ellipse curve. The effect of the variations of voltages and circuit parameters on the capability curves are also investigated and the microgrid (MG) steady-state operation area is obtained. In the proposed method, the DC-voltage variations are regulated by an additional voltage control loop based on a current reference correction signal. The above-mentioned approaches are derived thoroughly with mathematical equations. The effectiveness of the designed controllers is verified by a MATLAB/SIMULINK simulation platform (Matlab/Simulink R2014a, Mathworks, Inc.) with harmonically distorted intermittent loads. The results show the appropriate performance of the proposed controllers during both steady-state and transient dynamic conditions.

Abstract
We introduce HHL, a hierarchical variant of hybrid logic. We study first order correspondence results and prove a Hennessy-Milner like theorem relating (hierarchical) bisimulation and modal equivalence for HHL. Combining hierarchical transition structures with the ability to refer to specific states at different levels, this logic seems suitable to express and verify properties of hierarchical transition systems, a pervasive semantic structure in Computer Science.

Abstract

Abstract