Abstract
Mode-directed tabling is an extension to the tabling technique that supports the definition of modes for specifying how answers are inserted into the table space. In this paper, we focus our discussion on the efficient support for mode-directed tabling in the YapTab tabling system, which uses tries to implement the table space. We discuss 7 different modes and explain how we have extended and optimized YapTab's table space organization to provide engine support for them. Experimental results, in the context of benchmarks taking advantage of mode-directed tabling, show that our implementation compares favorably with the B-Prolog and XSB state-of-the-art tabling systems. © 2013 Springer-Verlag.

Abstract

Abstract
This paper presents a multiyear dynamic model to the Transmission Expansion Planning, TEP, problem to identify the most suitable set of projects as well as their scheduling along the planning horizon. The candidate plans are evaluated using a fitness function that incorporates operation and investment costs plus a set of penalty terms. These terms are associated with the level of losses, non-zero values for the power not supplied namely for the entire system and for n - 1 contingencies, financial limits, maximum number of projects to implement in each year or all along the horizon and the capability to accommodate not only the expected demand, but also uncertainties affecting the demand forecasts. Given the discrete nature of the problem, we adopted an enhanced approach of the PSO algorithm to solve it. This includes an evolutionary adaptation of the PSO movement rule as well as several modifications to ensure that along the iterative process each candidate solution is technically feasible given its discrete nature. The paper also reports the results of a set of tests to evaluate several design decisions related with the development of the Discrete Evolutionary PSO, DEPSO, as well as to compare the results of its application to the TEP with results reported by other researchers.

Abstract

Abstract
This study analyses the relationship between ownership concentration and firm value. Our findings, based on a dynamic panel data analysis, show that there is a quadratic relationship between the company's value and its ownership concentration. Additionally, our evidence suggests that for countries where investor protection is low, the relationship follows an inverted 'U' shape, while for countries where investor protection is high, the relationship is positive and nearly linear. Moreover, the influence of blockholders depends on their identity. This paper highlights the superior performance of family firms in controlling agency problems, a situation which contrasts vis-'-vis institutional shareholders. Finally, we report that the family effect is nonlinear. Indeed the positive effect starts to taper off at around 30% of ownership being somewhat smaller and less statistically significant between 30% and 50% of ownership. Moreover, in contrast to recent studies, the family effect is more pronounced in majority-controlled firms. © 2013 Inderscience Enterprises Ltd.

Abstract
Assistive technology enables people to achieve independence in the accomplishment of their daily tasks and enhance their quality of life. However, the development os assistive technology does not always follow user needs and expectations, comprising their usability and effectiveness. This paper discusses the design and evaluation strategies for assistive technologies applied to a blind navigation system case study. The research carried out focused on the gathering of user requirements for ensuring enhanced autonomy of blind people in their daily life. The picked requirements were used in an architecture that unifies the benefits of a redundant blind navigation system with a set of services that are provided by daily used information and communication technologies. The system combines guidance, navigation and information gathering, extending traditional aids with realtime knowledge of the surrounding environment to provide an enhanced assistive tool for autonomy of the blinds. Moreover, the developed solution fills the gap of existing solutions that require the users to carry a wide range of devices and, mostly, do not include mechanisms to ensure the autonomy of users in the event of system failure. © 2013 Springer-Verlag Berlin Heidelberg.