Splicing systems and the Chomsky hierarchy

In this paper, we prove decidability properties and new results on the position of the family of languages generated by (circular) splicing systems within the Chomsky hierarchy. The two main results of the paper are the following. First, we show that it is decidable, given a circular splicing language and a regular language, whether they are equal. Second, we prove the language generated by an alphabetic splicing system is context-free. Alphabetic splicing systems are a generalization of simple and semi-simple splicin systems already considered in the literature

Corporate monitoring by blockholders in Europe: empirical evidence of managerial disciplining in Belgium, France, Germany, and the UK

This study examines managerial disciplining in poorly performing firms using large panels for Belgian, French, German and UK firms. We consider the monitoring role of large blockholders, the market for share blocks, creditors, and non-executive directors. Board restructuring is correlated to poor performance, but not for France. Neither existing blockholders nor creditors play an active role in disciplining. Block purchases have a monitoring role in Belgium and Germany, but not in France and the UK. Large boards facilitate disciplining, but the role of non-executives is ambiguous. --corporate governance,managerial disciplining,ownership structure,CEO succession

Quality assessment and usage behavior of a mobile voice-over-IP service

Voice-over-IP (VoIP) services offer users a cheap alternative to the traditional mobile operators to make voice calls. Due to the increased capabilities and connectivity of mobile devices, these VoIP services are becoming increasingly popular on the mobile platform. Understanding the user's usage behavior and quality assessment of the VoIP service plays a key role in optimizing the Quality of Experience (QoE) and making the service to succeed or to fail. By analyzing the usage and quality assessments of a commercial VoIP service, this paper identifies device characteristics, context parameters, and user aspects that influence the usage behavior and experience during VoIP calls. Whereas multimedia services are traditionally evaluated by monitoring usage and quality for a limited number of test subjects and during a limited evaluation period, this study analyzes the service usage and quality assessments of more than thousand users over a period of 120 days. This allows to analyze evolutions in the usage behavior and perceived quality over time, which has not been done up to now for a widely-used, mobile, multimedia service. The results show a significant evolution over time of the number of calls, the call duration, and the quality assessment. The time of the call, the used network, and handovers during the call showed to have a significant influence on the users' quality assessments

Concertation sociale et transformations socio-économiques en Belgique, de 1944 à nos jours

The socioeconomic development of most European countries has been largely shaped by social dialogue, by negotiations between employers and workers representatives. To that respect, Belgium has played a pivotal role. The Belgian post-WW2 institutions, aimed at fostering social dialogue, are often alluded to as a reference. In sixty years, these institutions have changed, along with the transformations of the economic, social and political context. We study here the dynamical movement that simultaneously transforms the social dialogue, on the one hand, and the historical context in which it is anchored, on the other. We contrast two thirty-year periods: the golden age, followed by an age of upheaval. The former is characterized by the setting up and the extension of a coherent model while the latter rather appears as a defensive withdrawal in a context of crisis and of socioeconomic upheaval. In the midst of the turmoil, the social partners uneasily seek for meaningful responses.

Propagation of Shock Waves in Two Rooms Communicating through an Opening

Confined explosions represent a serious safety hazard as significant damage to humans and structures is observed, unlike in free-field explosions. An experimental small-scale study investigated the blast wave in a single-story building. The blast waves were generated by the detonation of a gaseous charge. The building was divided into two rooms by a movable wall which could be positioned at three different locations. The presence of an opening in this movable wall means that two rooms were considered: a transmitter room (TR) and a receptor room (RR). The configuration without the movable wall was also studied. Pressure profiles recorded with pressure gauges at ground level and on the wall presented numerous reflections. The damage effects were severe since the maximum overpressure never fell below 0.2 bar. Although this study is limited to a small scale and gaseous detonation charge, the results can be applied to a large scale and for a TNT charge

A Way To Get Students Consider Ethics And Sustainability In IOT Projects

Sustainability and ethical topics can be embedded and assessed in existing technical courses within an engineering curriculum. This article describes how we integrated a reflection on the importance of ethical and environmental aspects of connected objects through team-based project learning with computer science students in the second semester of their Bachelor degree. Small groups of three were given different projects, in which they had to implement the technical concepts learned in class using both virtual and physical components. The projects followed realistic scenarios chosen at random, each of them using a specific set of sensors and built to question either personal data collection, ethics or sustainability issues. At the end of the project, each group had to demonstrate their connected object proof of concept during an oral presentation and to prepare a group written report. The project is one of the continuous assessment elements of this module. After mapping the different projects and their associated sustainability and ethical topics, we present how the initial assessment grid of the project evolved into a three-fold version. The final grid explicitly invites students to explore sustainability and ethical aspects in their reports, in addition to the technical aspects, and includes a peer review section. Examining to what extent students developed an original reflection on sustainability and ethical aspects of their projects, we finally suggest possible extensions and improvements, and list some context elements that are to facilitate future implementations

L'observatoire : un instrument pour le suivi de la pauvreté

Poverty reduction is one of the major objectives of the current public policies. Monitoring poverty is twofold : (i) a static component aims at identifying and characterising the various forms of poverty, and (ii) a dynamic component aims, in a comprehensive way, at understanding their evolutions. The multidimensional aspect of poverty, and substitutions occurring among the various dimensions, make the search of the poverty determinants quite difficult. New investigation tools combining quantitative and qualitative approaches are then required to investigate poverty groups over large periods. For this objective, the “observatory” appears to be an appropriate monitoring tool: based on an independent structure collecting permanently information on specific population groups, it produces regular data on the situation and behaviour of these groups, for a set of users. One may distinguish among to types of “observatories”: the “synthetic observatory” gathering diverse information from various sources for a specific thematic objective, and the “field observatory” which, as in the Malagasy case, collects panel data on rural peculiar population. This efficient investigation tool needs, however, methodological input to improve its statistical represensativity and to be kept simple as information requirement is increasing with its functioning. (Full text in French)