Showing papers in "Elektrotechnik Und Informationstechnik in 2013"

Unexpected relevance: An empirical study of serendipity in retweets

Abstract: Serendipity is a beneficial discovery that happens in an unexpected way. It has been found spectacularly valuable in various contexts, including scientific discoveries, acquisition of business, and recommender systems. Although never formally proved with large-scale behavioral analysis, it is believed by scientists and practitioners that serendipity is an important factor of positive user experience and increased user engagement. In this paper, we take the initiative to study the ubiquitous occurrence of serendipitious information diffusion and its effect in the context of microblogging communities. We refer to serendipity as unexpected relevance, then propose a principled statistical method to test the unexpectedness and the relevance of information received by a microblogging user, which identifies a serendipitous diffusion of information to the user. Our findings based on large-scale behavioral analysis reveal that there is a surprisingly strong presence of serendipitous information diffusion in retweeting, which accounts for more than 25% of retweets in both Twitter and Weibo. Upon the identification of serendipity, we are able to conduct observational analysis that reveals the benefit of serendipity to microblogging users. Results show that both the discovery and the provision of serendipity increase the level of user activities and social interactions, while the provision of serendipitous information also increases the influence of Twitter users.

Power transformers with environmentally friendly and low flammability ester liquids

Abstract: To improve personal safety and reduce the environmental impact of electrical power supply, alternative insulation fluids are demanded for large power transformers. With their biodegradability, the fact that they can be produced from renewable resources, and the high fire point properties, ester fluids are becoming potential substitutes for mineral oil. A number of companies offer such alternative insulation fluids, and in many distribution transformers they are already used satisfactorily. So far, however, there is little experience for use of these liquids in large power transformers. Even in proven high-voltage applications with mineral oil, every change in transformer design or materials needs to be evaluated. Changing such a crucial component as the insulating liquid itself, the suitability must be proven most thoroughly. This paper illustrates various issues which must be clarified in order to successfully operate power transformers filled with these environmentally friendly, renewable and barely inflammable insulating liquids.

An overview of state of the art and research in the fields of sensible, latent and thermo-chemical thermal energy storage

Abstract: Due to the increase in volatile renewable power and heat generation (wind or solar), thermal energy storage (TES) has obtained growing importance and interest. The technology can be distinguished into three main types: sensible, latent and thermochemical storage. Apart from low and medium temperature heat applications, high temperature TES also is an attractive means to store power in the form of heat (before the thermodynamic transformation process). Thermochemical storage allows for long duration seasonal storage of energy.

Direct current in transformers: effects and compensation

Abstract: Due to the high magnetic conductivity of transformer cores, very small direct currents in the electric power grid are sufficient to cause half-cycle saturation of the core. Even minor DC-bias leads to a considerable increase of the noise level and to high reactive power consumption, as well as to a significant rise of no-load loss. In case of strong direct currents (e.g. GIC), the higher harmonic stray flux causes additional losses in metallic parts that can harm the transformer. Moreover, reactive power consumption can reach a level that is critical for the power grid.

Development trends in robotics

Abstract: Robotics has been a very fast growing field especially in the last years. In the late 1970s the first industrial applications of stationary unintelligent industrial robots were realised. Since the beginning of the 1990s a new generation of mobile, intelligent, cooperative robots has grown up. This new generation opens new applications areas, e.g. in production automation, in agriculture, in the food industry, in household, for medical and rehabilitation applications, in the entertainment industry as well as for leisure and hobby. Current developing trends are humanoid robots and robots supporting people in everyday life. Other intensive research areas are cooperative robots, bio inspired robots, ubiquitous robots and cloud robots. The following paper is divided into three parts: current state, future development trends as well as visions in robotics.

Modeling and control of a humanoid robot

Abstract: This work deals with modeling of humanoid robots, especially for planning motion using the Denavit-Hartenberg method to determine the inverse kinematics of used trajectory (Matlab/Simulink and SimMechanics). The simulations are applied to an existing robot, in order to determine the optimal trajectory for the robot motion.

Comparison of the usability and security of NFC’s different operating modes in mobile devices

Abstract: This paper highlights the benefits and drawbacks of NFC’s different operating modes with regard to their usability and security. Based on an analysis of both traditional and new communication concepts for mobile NFC devices, their current availability and, specifically, the features to provide security are evaluated. The result of this evaluation is a comparison between the availability, the usability and the security of NFC’s different operating modes.

Smart NFC-sensors for healthcare applications and further development trends

Abstract: A promising approach for the application of NFC in healthcare is the combination of the simple handling of NFC with different sensor functionalities. By an advanced design of the NFC-antenna and the surrounding hard- and software, the intelligent NFC-tag can operate as a smart sensor with NFC-interface for the transfer of measurement data. According to this principle, various sensor applications for health care scenarios can be realized. In this article several developments of NFC-sensor applications are introduced like NFC-based fill level measurement, NFC-based analog scale (position detection), NFC-based blood-glucose meter, NFC-based cryo-sensor for vials and NFC-based ultraviolet (UV) assessment for sun burn prevention. The main advantages of these applications are that all NFC-sensors can simply be used by medical, nursing staff or patients and consumers.

Une industrie normée ? Gouvernement par les normes, jeu sur les normes et internationalisation des chaînes de valeur dans le secteur pharmaceutique

Abstract: Dans le secteur pharmaceutique, les normes sont presentes a chaque maillon de la chaine de valeur. Ces normes, loin d’etre de simples enonces scientifiques ou techniques socialement inertes sont des construits politiques et sociaux dont se saisissent des acteurs divers au pouvoir variable. Est examine ici, dans une perspective d’economie politique des normes, le cycle des normes pharmaceutiques (bonnes pratiques cliniques, de laboratoire et de fabrication), de leur negociation a leur mise en application dans les entreprises, en mettant en evidence leur role capital dans le gouvernement du secteur, en meme temps que les jeux d’acteurs et les arrangements locaux autour des normes. Celles-ci se sont developpees « par sauts » a la suite de crises sanitaires et sous la pression continue de l’industrie pharmaceutique. Le contexte d’internationalisation pousse a une harmonisation internationale facilitant la coordination au sein des chaines de valeur globales en meme temps qu’il rend de plus en plus difficile le controle des normes par les agences nationales. Ce contexte est egalement marque par un neoliberalisme pharmaceutique redefinissant le role et les moyens de ces agences.

Régulation monétaire et financière et viabilité des économies de marché

Abstract: Les modeles d’evaluation interne decentralisee (autoregulation), qui se substituent aux mecanismes de regulation publique, ne sont pas en mesure d’avoir une vision macroeconomique a long terme ni de prendre en compte les interdependances entre les acteurs prives et les marches. Des lors, ils se revelent incapables de faire face a des situations de crise systemique. De surcroit, les schemas de supervision liberale reduisent le champ d’action des Autorites monetaires et limitent la portee systemique de leur intervention en cas de crise d’envergure. Par consequent, l’absence de mecanismes de regulation macroeconomique apparait comme l’une des raisons de l’apparition et la persistance des crises financieres generalisees. Une relecture du schema Minskien d’instabilite financiere et des resultats des modeles de conventions, de financement par LBO et de dissonance cognitive montre que la crise financiere actuelle remet en question deux principes du mode de regulation financiere du capitalisme moderne : 1) La croyance en la capacite des marches a corriger les erreurs de jugement des acteurs decentralises sans une intervention publique structurelle ; 2) L’efficacite d’une autoregulation des marches par rapport aux schemas de regulation publique. Ces principes se revelent incapables aujourd’hui d’assurer la continuite des rapports economiques sous leur forme actuelle si bien qu’un debat de fond sur de nouveaux mecanismes de regulation macro-prudentielle, visant a renforcer la viabilite des systemes monetaires et financiers, parait necessaire.

Paraphrasing adaptation for web search ranking

Abstract: Mismatch between queries and documents is a key issue for the web search task. In order to narrow down such mismatch, in this paper, we present an in-depth investigation on adapting a paraphrasing technique to web search from three aspects: a search-oriented paraphrasing model; an NDCG-based parameter optimization algorithm; an enhanced ranking model leveraging augmented features computed on paraphrases of original queries. Experiments performed on the large scale query-document data set show that, the search performance can be significantly improved, with +3.28% and +1.14% NDCG gains on dev and test sets respectively.

Contribution of synchronous condensers for the energy transition

Abstract: In recent years a revival of rotating synchronous condensers could be seen all over the world. This trend is mainly driven by the introduction of enduring energy production. The change in energy mix is leading to the replacement of conventional energy production with synchronous machines by “low inertia” and “low thermal time constant” power park modules. Power park modules are represented by wind farms and registrable solar power plants. Compared to power park modules synchronous machines have a high thermal time constant and must therefore not be limited during short circuit events in its reactive power capability. Additionally, synchronous condensers have a natural mechanical inertia, which cannot be reached by modern power park modules. Therefore synchronous condensers complement power park modules for transmission upgrade projects and help to improve reliability, preserve future energy options and contribute to economic stability. Different design considerations are discussed.

Condition assessment of instrument transformers using dielectric response analysis

Abstract: Dielectric response analysis is an advanced technique, providing information about the insulation condition of the measured test object. It is typically used for power transformers, where the water content in the solid cellulosic insulation can be assessed. Water in oil-paper/pressboard insulations is decreasing the dielectric strength, accelerating the ageing and causing the bubble effect at high temperatures. Also instrument transformers are oil-paper insulated and therefore exposed to the harming effects of water. The condition assessment of the insulation system of instrument transformers has not played an important role up to now since typical measurement methods which might be used for power transformers are not applicable here. For example oil sampling is often avoided due to the small oil volume. However, the increasing age is leading to a higher risk of explosions, which can damage surrounding parts and cause high follow-up costs. This paper introduces a new approach to use the dielectric response analysis for condition assessment of instrument transformers. The measurement of the dielectric response in a wide frequency range (e.g. 100 μHz up to 5 kHz) provides information about the insulation condition and especially for oil-paper/pressboard insulations about the water content in the solid insulation. The measured curve is formed by the superposition of the dielectric response of the cellulosic material and the oil. It is reflecting the conductivity and polarization effects of each material. Due to the high content of cellulosic material, the oil has a minor impact on the dielectric response of an instrument transformer and the curve is highly determined by the behavior of the cellulosic material. The resulting curve can be used for the assessment of the insulation condition in various ways. Qualitative comparisons, e.g. between instrument transformers of the same type and age, might give general information which of these is in better condition. The dissipation factor and the capacitance trend can also deliver valuable data. Furthermore, the water content in the solid insulation can be assessed. An automatic analysis algorithm compares the measured dielectric properties of the actual instrument transformer with modeled dielectric properties to calculate the water content in the solid insulation. This paper describes the modeling in concerns of water content, oil conductivity and geometry. Furthermore, the influences of temperature and ageing products are explained. To confirm the validity of this assessment, measurements on several instrument transformers in service were performed. Dielectric response curves and the trend of the capacitances for new and aged instrument transformers with different water contents are discussed. Selected examples presented in this paper show, that the dielectric response is well-modeled and the water content can be derived. Also ageing effects can be observed. To avoid explosions of their instrument transformers, this method is now regularly used by TNB.

De la responsabilité sociétale d’une exploitation agricole à la mesure de sa performance globale. Revue de la littérature et application avec la méthode IDEA

Abstract: Cet article analyse comment le concept de Responsabilite Societale de l’Entreprise (RSE) a ete decline en agriculture au plan theorique et dans sa mesure. L’analyse des courants de pensee de la RSE (americain et europeen) ainsi que des concepts associes pour sa mesure, performance globale versus performance societale, montre qu’une exploitation agricole Societalement Responsable renvoie au plan theorique au concept d’exploitation agricole durable. Une typologie des parties prenantes d’une exploitation agricole Societalement Responsable est proposee en mobilisant la dimension normative de la Theorie des Parties Prenantes. Enfin, l’analyse comparee des outils de mesure de ces deux concepts de performance montre que la methode IDEA (Indicateurs de Durabilite d’une Exploitation Agricole) s’inscrit dans le champ europeen de la RSE et mesure la performance globale d’une exploitation agricole.

L’Union européenne est-elle une source de coopération inter-organisationnelle ? Le cas du réseau voice

Abstract: Cette etude s’interesse a la cooperation inter-organisationnelle, un aspect delaisse de la recherche en relations internationales. L’analyse du cas de la politique humanitaire europeenne met en lumiere les facteurs, les dynamiques et les effets de la cooperation au sein d’un reseau d’ong, et entre ce reseau et les institutions europeennes. La construction de liens entre differentes theories permet de distinguer trois phases dans la vie des reseaux. Si les ong se rassemblent pour etre reconnues comme des partenaires credibles par les organisations intergouvernementales, les reseaux formes se caracterisent par une structure complexe de delegation visant a repondre aux interets des membres et de l’institution ciblee. La flexibilite supposee des reseaux ne les protege toutefois pas des pathologies dont souffrent les organisations internationales (faible adaptabilite, resistance au changement…).

Construire sa légitimité à l’aide des normes environnementales. L’analyse de cycle de vie des produits dans le secteur des revêtements de sol

Abstract: Au vu de la proliferation de normes environnementales et des outils d’analyse d’impacts des produits et/ou des activites industrielles, nous nous interrogeons sur la maniere dont se dessine la performance environnementale des entreprises. Alors que de nombreux chercheurs considerent cette notion comme une donnee a priori a partir desquels sont etayees leurs demonstrations, nous adoptons une demarche inverse, preferant debuter notre analyse des outils et moyens utilises pour en deduire la representation implicite qu’est faite de la performance environnementale. Nous etudierons ainsi l’outil le plus utilise par les entreprises, l’analyse de cycle de vie, dans un secteur vivement critique sur le plan environnemental, le secteur des revetements de sols resilients sur le marche de l’Europe de l’Ouest. Nous montrons que la prise en compte des risques environnementaux par les leaders francais a fait l’objet d’un long processus de convergence. Cette convergence a engendre une conception commune de la performance environnementale en se presentant sous la forme de strategies d’innovation semblables ainsi que l’elaboration d’analyses de cycle de vie permettant a la fois aux industriels et au secteur de s’adapter aux nouvelles exigences.

La défaite de la sdn face aux nationalismes des majorités : la Section des minorités et l’irrecevabilité des pétitions « hors traité »

Abstract: En contraste avec d’autres unites de la sdn, la Section des minorites tend a limiter ses missions. Elle n’appuie pas l’extension des traites ni ne consulte les entites non gouvernementales ; elle n’alerte pas l’opinion publique sur la montee du fascisme. Tres important, la Section contribue a consolider l’image « identitaire » des revendications nationales non etatiques. En fait, elle ne pense pas les conflits entre majorites et minorites comme des conflits politiques entre droits concurrents, a la fois collectifs et individuels. Peu etudiees jusqu’ici, les decisions sur l’irrecevabilite de certaines petitions, notamment celles non couvertes par les traites, illustrent ces propos. Independamment de l’influence des grandes puissances, la Section des minorites soutient une philosophie politique favorable aux nationalismes des majorites sans contradiction avec une volonte de juridicisation du domaine.

De l’évaluation des politiques publiques à la « performance totale »

Abstract: L’article defend la these suivante : l’evaluation des politiques publiques s’amenage de plus en plus en une succession de dispositifs concrets visant, dans les faits, a mesurer les performances des services publics. Cela reduit en partie la portee des processus d’evaluation en l’inserant dans des dispositifs realistes caracterises par le developpement de la metrologie. Cela transforme aussi la maniere par laquelle la realite de l’efficacite est mise a jour. Cette these s’accompagne de l’idee que la preeminence de la « performance » est le symptome d’une double dissolution : dissolution d’abord de l’evaluation des politiques dans la mesure des performances des services publics. Dissolution ensuite, de la performance collective, et avec elle, du progres social, dans la somme des performances individuelles.

Flexible thermische Kraftwerke für die Energiewende

Abstract: Systemstabilitat und Versorgungssicherheit sind die wesentlichen Herausforderungen, die im Zuge der Energiewende im Laufe der nachsten Jahrzehnte an das Stromnetz und seine Teilnehmer in immer scharferer Form gestellt werden. Der Artikel stellt dar, welche Einzelaufgaben in welchen Zeitskalen damit verbunden sind. Konventionelle thermische Kraftwerke ubernahmen diese Aufgaben in der Vergangenheit und werden sie grosenteils auch in der Zukunft ubernehmen mussen und konnen. Einzelne Aspekte, wie Schwungmasse, Frequenzstabilitat, hohe Leistungsrampen, aber auch die Einbindung in zukunftsweisende Konzepte, wie Power-to-Gas, werden intensiver betrachtet und zeigen die unverzichtbare Rolle der konventionellen thermischen Kraftwerke und ihre widerspruchsfreie Einbindung in die Ziele der Energiewende.

Dipesh Chakrabarty et John M. Hobson sur l’eurocentrisme et la critique des relations internationales

Abstract: Les auteurs presentent et analysent le projet theorique de Dipesh Chakrabarty – un important representant des etudes postcoloniales – de « provincialiser » certains developpements sociohistoriques de l’Europe. Ils se penchent egalement sur la critique de l’eurocentrisme de John M. Hobson, un important representant de la sociologie historique neoweberienne des relations internationales. Apres avoir presente ces contributions aux theories postcoloniales et au virage anti-eurocentriste de certains sociologues neoweberiens, les auteurs soulignent que ces theories ont tendance a s’elever contre une version depassee du marxisme, ce qui les conduirait a negliger l’etude de l’articulation entre la modernite des relations internationales et l’emergence d’un ordre global capitaliste. Les auteurs concluent en defendant l’importance d’un detour par la theorie sociale classique pour l’examen des specificites des arguments eurocentristes dans les relations internationales passees et contemporaines.

End of life management of industrial robots

Abstract: End of life management (EOL) is currently a hot topic in the electronics industry. Currently, mostly IT equipment and goods of consumer electronics are considered. In the nearest future automation equipment has also to be taken into account. There are three possibilities depending on the age and kind of the device: resell–reuse–recycle, called the “3Rs”. For recycling fully or semi-automated disassembly will gain in importance in the nearest future also for robots. Producers of robots have to take into account EoL because of regulations and laws as well as according to ethical codes contributing to protection of the environment. Based on previous works a real example will be presented and discussed.

Penser et maîtriser l’innovation ? Les Forces armées américaines, de la révolution à la transformation 1990-2011

Abstract: Cet essai s’inscrit dans le cadre des reflexions portant sur l’innovation en matiere militaire aux Etats-Unis. Il souleve specifiquement quatre questions : Dans quelle mesure les Forces armees americaines ont-elles su se reinventer dans le contexte de l’apres-guerre froide ? Quelles idees maitresses les ont guidees ? Comment ont-elles ete appliquees ? Et quelles lecons peut-on tirer de cette experience apres vingt ans ? Deux concepts, qui ont inspire l’effort de reflexion et de reforme americain, retiennent notre attention : la revolution dans les affaires militaires (ram) et la « transformation ». C’est la mise en oeuvre de ces deux concepts qui est analysee, de l’administration Clinton a celle du president Obama.

La Chine en Arctique : Stratégie raisonnée ou approche pragmatique ?

Abstract: Depuis quelques annees, de nombreux articles de presse et textes d’analystes predisent un regain de tension dans l’Arctique, dans ce qui serait une course a l’appropriation des espaces maritimes. Dans cette course, la Chine chercherait a se poser en acteur incontournable. Nombre d’analyses mettent l’accent sur les ambitieux projets chinois dans la region et sur le potentiel destabilisateur de ces ambitions. En realite, si le gouvernement chinois semble preciser, depuis peu, une politique arctique, rien ne laisse entendre que la Chine va contester les revendications des pays riverains ou chercher a imposer un coup de force pour s’emparer des ressources supposees de la region.

Tuned medium-band UHF PD measurement method for GIS

Abstract: SUMMARY In order to replace the lightning impulse test, a very sensitive PD-measurement is required for onsite tests of GIS [1]. The most sensitive UHF-PD-measurement technique consists of low-noise high –gain broadband amplifiers applied directly to the PD-sensors combined with the manual selection of possible resonant frequencies in the frequency spectrum for narrowband signal extraction with a bandwidth of some MHz. Further a correlation with the test voltage will lead to phase resolved signal display. The only disadvantage is the time consuming visual selection of the optimal centre frequency of the narrowband measurement system done sensor by sensor compared to broadband or fixed band measurement techniques. The broadband system design has the disadvantage of significantly reduced measurement sensitivity as soon as interfering frequencies are located within the measurement bandwidth. Beside this, in principle, the signal to noise ratio is lower for a broadband measurement system compared to a narrowband system. The narrowband system with fixed frequencies show poor or no sensitivity when the GIS resonant frequency caused by a PD source do not correspond with the narrow band measurement frequency or when interfering frequencies appear at the fixed measurement frequencies. The tuned medium band UHF PD measuring system design consists of one or more manually pretuned band-pass filters with a bandwidth of 50 ... 150 MHz applied in a frequency range of approx. 100 ... 2000 MHz. The selection of the centre frequencies should be based on the individual resonant frequencies of the PD-sensors determined by the CIGRE sensitivity check [2] on site. The medium bandwidth allows to integrate the individually shifted resonant frequencies of a PD-signal at a PDsensor within the measurement band, caused by different PD locations. Due to the wider bandwidth, the probability of missing PD-signals at a specific centre frequency is much lower than with the narrow band technique [3]. The evaluation of measurements carried out in different environment and different types of GIS showed a high possibility that a medium bandwidth is still narrow enough to avoid fix frequency disturbances by the use of a suitable centre frequency. Using several tuned frequency bands the probability of missing the resonance frequencies of a PD-signal is even lower and additionally allows to conduct a first coarse localization of the PD-source based on the frequency dependent damping of the PD-signal. The main advantage of the proposed design is the combination of simultaneous measurement with optimal sensitivity based on selective avoiding of fixed band interfering frequencies together with tuning into the most sensitive frequency band of each individual PD sensor of a GIS.

Thermal management of LED systems

Abstract: A short overview on thermal management solutions for LED systems is presented. Heat transfer modes of these systems are described, from junction to ambient, giving an estimate on the contribution of each process involved, focusing on the key parameters to solve in a design optimization. We present conduction, radiation, natural and forced convection heat transfer by measurement results of our model systems.

Introduction of very high bit rates for NFC and RFID

Abstract: This article gives a detailed insight into the very high bit rates (VHBR) technology for the data transfer with NFC and RFID. In the first part enhancements and changes to the ISO/IEC 14443 and related standards are discussed. In the second part an analysis of different bit rates with focus on communication parameters and bit error rates are provided.

Équilibres régionaux et stratégies des non-puissances : Les cas du Golfe et de l’Asie du Sud-Est

Abstract: Si le programme de recherche realiste s’est largement focalise sur les strategies des grandes puissances, il s’est montre relativement indifferent a celles qu’ont mises en place les autres Etats formant le systeme international. En prolongeant les axiomes realistes, ce travail montre qu’il existe une strategie particulierement efficace pour les non-puissances, celle-ci consistant en une forme originale d’« engagement multidirectionnel » qui vise a creer un equilibre au sein du systeme. Axe sur deux regions majeures du systeme mondial contemporain, ce travail montre que les non-puissances du Golfe et de l’Asie du Sud-Est ont mis en place de telles strategies dans l’apres-guerre froide.

Electrical Power Vision 2040 for Europe—a EUREL study

Abstract: A special task force of EUREL, the European organisation of electrical engineers, has recently published the study “Power Vision 2040 for Europe”. The study investigates the actual status of the power supply of the EU27+, estimates the future electricity demand and identifies future applicable technologies. As part of the study scenarios for the future European power supply were developed.

Réseaux territoriaux d’organisations et processus de normalisation. Le cas de la GRH dans les services à la personne

Abstract: Les services a la personne connaissent aujourd’hui un developpement soutenu, tant en France que dans la plupart des pays europeens et occidentaux. Ces services regroupent un ensemble tres divers d’activites economiques realisees aupres des particuliers a leur domicile. Ce secteur connait de profonds changements dans sa structuration et dans ses modalites de gestion, dus a l’evolution de l’environnement institutionnel dans le sens d’une rationalisation des couts, d’un renforcement des imperatifs gestionnaires et d’une mise en concurrence accrue. Dans ce contexte, nous proposons d’analyser les roles des reseaux territoriaux d’organisations dans le processus de normalisation d’un champ d’activite, en ce qui concerne les pratiques de gestion des ressources humaines. A partir d’une etude de cas dans le champ des services a la personne, nous montrons que les reseaux territoriaux d’organisations peuvent occuper trois roles non exclusifs dans un processus de normalisation : diffuseur, traducteur et co-constructeur de normes.