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Joint Interference and Power Minimization for Fault-Tolerant Topology in Sensor Networks

Energy conservation is crucial in wireless ad hoc sensor network design to increase network lifetime. Since communication consumes a major part of the energy used by a sensor node, efficient communication is important. Topology control aims at achieving more efficient communication by dropping links and reducing interference among simultaneous transmissions by adjusting the nodes’ transmission power. Since dropping links make a network more susceptible to node failure, a fundamental problem in wireless sensor networks is to find a communication graph with minimum interference and minimum power assignment aiming at an induced topology that can satisfy fault-tolerant properties. In this paper, we examine and propose linear integer programming formulations and a hybrid meta-heuristic GRASP/VNS (Greedy Randomized Adaptive Search Procedure/Variable Neighborhood Search) to determine the transmission power of each node while maintaining a fault-tolerant network and simultaneously minimize the interference and the total power consumption. Optimal biconnected topologies for moderately sized networks with minimum interference and minimum power are obtained using a commercial solver. We report computational simulations comparing the integer programming formulations and the GRASP/VNS, and evaluate the effectiveness of three meta-heuristics in terms of the tradeoffs between computation time and solution quality. We show that the proposed meta-heuristics are able to find good solutions for sensor networks with up to 400 nodes and that the GRASP/VNS was able to systematically find the best lower bounds and optimal solutions.

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Software Architecture Patterns for System Administration Support

Many quality aspects of software systems are addressed in the existing literature on software architecture patterns. But the aspect of system administration seems to be a bit overlooked, even though it is an important aspect too. In this work we present three software architecture patterns that, when applied by software architects, support the work of system administrators: PROVIDE AN ADMINISTRATION API, SINGLE FILE LOCATION, and CENTRALIZED SYSTEM LOGGING. PROVIDE AN ADMINISTRATION API should solve problems encountered when trying to automate administration tasks. The SINGLE FILE LOCATION pattern should help system administrators to find the files of an application in one (hierarchical) place. CENTRALIZED SYSTEM LOGGING is useful to prevent coming up with several logging formats and locations. Abstract provided by the authors. Published in PLoP '13: Proceedings of the 20th Conference on Pattern Languages of Programs ACM.

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Software Architecture Patterns for System Administration Support

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Cell control with agents

A software system is described that uses the agent concept in the Cell Control layer. Important design goals are: the system continues as good as possible after a process crash, crashed processes are recreated whenever possible, and equivalent workstations are allocated dynamically. This project is carried out mainly to investigate whether the agent concept is applicable in such a situation. The system is not operational yet, but will be built in the period ahead. In addition, a graphic simulator for a small manufacturing system will be built for testing the agent structure.

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Veilig op weg met een rijassistent

De auto is niet meer weg te denken in onze huidige westerse maatschappij en bezet een belangrijke plaats in zowel ons economische als sociale leven. Hoewel Nederland al een van de meest verkeersveilige landen ter wereld is, waren er toch nog 811 verkeersdoden in 2006. Als we ons echter realiseren dat dit slechts een kwart is van de ruim 3200 verkeersdoden in 1972, is sindsdien al veel bereikt. De Nederlandse overheid streeft naar een verdere reductie tot minder dat 580 verkeersdoden in 2020. De daarvoor noodzakelijke verbeterde verkeersveiligheid zal voor een groot deel moeten komen uit nieuwe voertuigtechnologie die ongevallen helpt voorkomen (actieve veiligheid) en de gevolgen ervan beperkt (passieve veiligheid). Een auto veilig door het hedendaagse verkeer loodsen is geen eenvoudige taak, zeker niet onder slechte weersomstandigheden en bij complexe of onoverzichtelijke verkeerssituaties. Het is dan ook niet verwonderlijk dat bij het overgrote deel van de verkeersongevallen de oorzaak, minstens ten dele, bij een menselijke fout ligt. Intelligente voertuigsystemen, die met behulp van aan het voertuig verbonden omgevingssensoren het verkeer rond het voertuig monitoren, kunnen de bestuurder assisteren. Als er zich geen bijzonderheden voordoen is de bestuurder het meest gebaat bij informatieve- en comfortverhogende systemen. Als er een gevaarlijke situatie dreigt te ontstaan, komen de veiligheidssystemen in beeld. Naarmate de kans op een ongeval toeneemt, lijkt een grotere mate van ondersteuning (van waarschuwen, via assisteren tot interveniëren) gewenst. Vanwege hun veiligheidskritische karakter moeten actieve veiligheidssystemen voldoen aan hoge eisen ten aanzien van prestatie (hoge nauwkeurigheid), robuustheid (weersomstandigheden en wegcondities) en betrouwbaarheid. Hier liggen enorme uitdagingen in zowel het ontwerp als de evaluatie van dergelijke systemen waaraan het lectoraat Automotive control van Fontys Hogescholen door praktijkgericht onderzoek en vraaggestuurd onderwijs wil bijdragen.

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Formation of the conscience : pedagogic acting or bargaining?

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Formation of the conscience : pedagogic acting or bargaining?

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Time-out or switch?

Pupils with problem behaviours are challenging teachers as well as they are a challenge to teachers to find a way to teach them what curricula prescribe. Especially middle school teachers and those working in schools for special education are con-fronted with pupils with behavioural problems. There, teachers experience hard classes and find it difficult to fit classroom management with the pupils needs. In this paper we focus on two questions: is pullout an effective treatment to handle problem behaviour? do special classes have advantages for pupils who were pulled out or not? First we present a theoretical framework about pullout and we explicit our expectations. Then we describe the methods of our research in schools for special educa-tion during two months for students (N=759) when pulled out. We examined the reason of pulling out and the interactions during the process outside the classroom and the return. Because teachers noticed date and time of the removal, it was possible to use survival analysis to show the effects of the treatment. We found that pullout occurs under quite different circumstances, so the treatment integrity is a problem because deficiency of the intervention leads to repeated pullout. The data also showed that special classes for pupils who are pulled out seem to trigger and/or in-tensify the process itself. So, we conclude that these classes have a contra-productive effect.

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Training Intercultural Competence in the International Classroom

The international classroom is presumably a far more effective learning environment for the acquisition of intercultural competence when students receive adequate training to make the most of their intercultural encounters. This paper provides a summary of the intercultural training taught to first-year students of an international programme in The Hague University of Applied Sciences. The purpose of the paper is to investigate how the students respond to this intercultural training as well as what signs of intercultural awareness they show after completing the course. The findings were obtained via qualitative methods such as semi-structured interviews, observations and student homework assignments. Overall, students evaluate the training positively. Furthermore, students show some awareness of the necessary ingredients for effective intercultural communication in the international classroom as well as of the challenging nature of this communication due to cultural diversity. Finally, this paper provides recommendations from the facilitators on stimulating intercultural learning in the international classroom.

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Training Intercultural Competence in the International Classroom

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Experiences of Norwegian Mothers Attending an Online Course of Therapeutic Writing Following the Unexpected Death of a Child

The unexpected death of a child is one of the most challenging losses as it fractures survivors’ sense of parenthood and other layers of identity. Given that not all the bereaved parents who have need for support respond well to available treatments and that many have little access to further intervention or follow-up over time, online interventions featuring therapeutic writing and peer support have strong potential. In this article we explore how a group of bereaved mothers experienced the process of participating in an online course in therapeutic writing for the integration of grief. Our research questions were: How do parents who have lost a child experience being part of an online course in therapeutic writing? What are the perceived benefits and challenges of writing in processing their grief? We followed an existential phenomenological approach and analyzed fieldwork notes (n = 13), qualitative data from the application and assessment surveys (n = 35; n = 21), excerpts from the journals of some participants (n = 3), and email correspondence with some participants (n = 5). We categorized the results in three meaning units: (1) where does my story begin? The “both and” of their silent chaos; (2) standing on the middle line: a pregnancy that does not end; (3) closures and openings: “careful optimism” and the need for community support. Participants experienced writing as an opportunity for self-exploration regarding their identities and their emotional world, as well as a means to develop and strengthen a bond with their children. They also experienced a sense of belonging, validation, and acceptance in the online group in a way that helped them make sense of their suffering. Online writing courses could be of benefit for bereaved parents who are grieving the unexpected death of a child, but do not replace other interventions such as psychotherapy. In addition to trauma and attachment informed models of grief, identity informed models with a developmental focus might enhance the impact of both low-threshold community interventions and more intensive clinical ones. Further studies and theoretical development in the area are needed, addressing dialogical notions such as the multivoicedness of the self. Lehmann OV, Neimeyer RA, Thimm J, Hjeltnes A, Lengelle R and Kalstad TG (2022) Experiences of Norwegian Mothers Attending an Online Course of Therapeutic Writing Following the Unexpected Death of a Child. Front. Psychol. 12:809848. doi: 10.3389/fpsyg.2021.809848

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Experiences of Norwegian Mothers Attending an Online Course of Therapeutic Writing Following the Unexpected Death of a Child

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Vocational education in the Netherlands: in search of a new identity

When the Netherlands developed a national system of vocational education at the end of the 19th century, it was a direct answer to obvious shortcomings in the technical and trade professions (De Jonge, 1968). It concentrated on training craftsmen for the traditional, mainly agrarian economy, and technicians for the new, industrial economy. The training being offered was closely related to actual professional practices. In the first place, there was a very stable occupational structure, in which professional knowledge and skills did not become obsolete quickly. This, in turn, made it possible that education was -and remained - up-to-date. Secondly, almost all teachers were also experienced craftsmen, who only started teaching after a long career. The teachers learned actual professional practices through direct experience. In addition, students were also frequently familiar with actual practice, because the occupational structure was so stable: they knew exactly for which profession they were being trained. A stable occupational structure, a clear occupational orientation by the students, and teachers with extensive firsthand work experience ensured that vocational education was a powerful learning environment. For this reason, a dual system had hardly any added value. A consequence is that the apprenticeship system in the Netherlands - as opposed to almost all surrounding countries - had a lower status and fewer students than full-time education (Teerling & Bijveld, 1982).

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Joint Interference and Power Minimization for Fault-Tolerant Topology in Sensor Networks