Impact of antenna choices on the reliability of mobile broadband transmission at mm-wave frequencies

This paper deals with the impact of several antenna choices on the radio transmission performance within a cellular Mobile Broaband System (MBS) currently under research in Europe. Several antenna types are considered, namely switchble-beam antennas and adaptive antennas employing a phased array approach.

Expérimentation de l'apprentissage par problèmes (APP) en formation initiale pour développer les compétences professionnelles des enseignants au primaire

Ce mémoire fait état d'un changement de pratique dans la manière de former les futurs enseignants au primaire. Il permet de se familiariser avec l'apprentissage par problèmes (APP) et de comprendre l'intérêt d'utiliser cette méthode d'apprentissage dans une visée de professionnalisation des enseignants (Béchard, 2001, Iglesias, 2002, Lessard, 2005, Galand et Frenay, 2005). S'appuyant sur une méthodologie de recherche-intervention, notre démarche s'est inscrite dans une approche descriptive et compréhensive. Ainsi, cette étude nous a permis d'expérimenter l'APP dans un cours de didactique du français du programme de BEPP de l'Université de Sherbrooke, pour ensuite exposer les difficultés rencontrées et les bénéfices perçus par les étudiants en lien avec l'utilisation de l'APP, particulièrement en ce qui a trait au développement des compétences professionnelles. Les résultats obtenus semblent très prometteurs quant à l'atteinte des objectifs visés.

LifeSpeeder: a web and mobile platform for events location

The use of smartphones and tablets as become almost banal in these days. Smartphones, besides serving their main purpose of making and receiving calls, come to be one of the main equipments to obtain information from the Internet, using the commonly installed browsers or through the use of dedicated applications. Furthermore, several other devices are also very frequent to the majority of the modern smartphones and tablets in the market (e.g., GPS - Global Positioning System). This devices give the current systems a very high potential of usage. One example of applicability, comes from the wish to find and navigate to events or activities which are or will soon be occurring near the user. The LifeSpeeder platform is one of the first applications in the mobile equipment market of applications which take into consideration exactly what we have just outlined, i.e., a mobile and desktop application which allows the users to locate events according with their preferences and to get help navigating to them. In this paper we briefly describe the LifeSpeeder's front and back-end. © 2014 Springer International Publishing.

virtX: ein Lehr- und Lernsystem für mobile Röntgengeräte zur Verbesserung der Ausbildung im Strahlenschutz

Hintergrund und Fragestellung: Die durch röntgentechnische Diagnoseverfahren in der Medizin entstehende Strahlenbelastung für Patient und Personal soll laut Strahlenschutzverordnung so gering wie möglich gehalten werden. Um dieses zu erreichen ist ein professioneller und bedachter Umgang mit den Röntgengeräten unabdingbar. Dieses Verhalten kann derzeit jedoch nur theoretisch vermittelt werden, da sich ein Üben mit realer Strahlung von selbst verbietet. Daher stellt sich die Frage wie man die Strahlenschutzausbildung durch eine verbesserte Vermittlung der komplexen Thematik unterstützen kann. Methoden: Das CBT-System (Computer Based Training) virtX, welches das Erlernen der korrekten Handhabung mobiler Röntgengeräte unterstützt, wurde um Aspekte aus dem Bereich des Strahlenschutzes erweitert. Es wurde eine prototypische Visualisierung der entstehenden Streustrahlung sowie die Darstellung des Nutzstrahlenganges integriert. Des Weiteren wurde die Berechnung und Anzeige der virtuellen Einfallsdosis für das durchstrahlte Volumen sowie für den Bereich des Bildverstärkers hinzugefügt. Für die Berechnung und Visualisierung all dieser Komponenten werden die in virtX parametrisierbaren C-Bogen-Einstellungen, z.B. Stellung der Blenden, Positionierung des Röntgengerätes zum durchstrahlten Volumen und Strahlenintensität, herangezogen. Das so erweiterte System wurde auf einem dreitägigen Kurs für OP-Personal mit über 120 Teilnehmern eingesetzt und auf der Basis von Fragebögen evaluiert. Ergebnisse: Von den Teilnehmern gaben 55 einen ausgefüllten Evaluations-Fragebogen ab (Responserate 82%). Das Durchschnittsalter der 39 weiblichen und 15 männlichen Teilnehmer (einer o.A.) lag bei 33±8 Jahren, die Berufserfahrung bei 9,37±7 Jahren. Die Erfahrung mit dem C-Bogen wurde von einem Teilnehmer (2%) mit „Keine oder bisher nur Einführung erhalten“, von acht Teilnehmern (14%) mit „bediene einen C-Bogen gelegentlich“ und von 46 (84%) mit „bediene einen C-Bogen regelmäßig“ angegeben. 45 (92%) der Teilnehmer gaben an, durch die Visualisierung der Streustrahlung etwas Neues zur Vermeidung unnötiger Strahlenbelastung dazugelernt zu haben. Schlussfolgerung: Trotz einer bislang nur prototypischen Visualisierung der Streustrahlung können mit virtX zentrale Aspekte und Verhaltensweisen zur Vermeidung unnötiger Strahlenbelastung erfolgreich vermittelt werden und so Lücken der traditionellen Strahlenschutzausbildung geschlossen werden.

Hybrid authentication systems: towards robust user authentication on wireless and mobile devices using biometric technologies

Adequate user authentication is a persistent problem, particularly with mobile devices, which tend to be highly personal and at the fringes of an organisation's influence. Yet these devices are being used increasingly in various business settings, where they pose a risk to security and privacy, not only from sensitive information they may contain, but also from the means they typically offer to access such information over wireless networks. User authentication is the first line of defence for a mobile device that falls into the hands of an unauthorised user. However, motivating users to enable simple password mechanisms and periodically update their authentication information is difficult at best. This paper examines some of the issues relating to the use of biometrics as a viable method of authentication on mobile wireless devices. It is also a critical analysis of some of the techniques currently employed and where appropriate, suggests novel hybrid ways in which they could be improved or modified. Both biometric technology and wireless setting based constraints that determine the feasibility and the performance of the authentication feature are specified. Some well known biometric technologies are briefly reviewed and their feasibility for wireless and mobile use is reviewed. Furthermore, a number of quantitative and qualitative parameters for evaluation are also presented. Biometric technologies are continuously advancing toward commercial implementation in wireless devices. When carefully designed and implemented, the advantage of biometric authentication arises mainly from increased convenience and coexistent improved security.

Human Computer Interaction using gestures for mobile devices and serious games: A review

The Human-Computer Interaction (HCI) with interfaces is an active challenge field in the industry over the past decades and has opened the way to communicate with the means of verbal, hand and body gestures using the latest technologies for a variety of different applications in areas such as video games, training and simulation. However, accurate recognition of gestures is still a challenge. In this paper, we review the basic principles and current methodologies used for collecting the raw gesture data from the user for recognize actions the users perform and the technologies currently used for gesture-HCI in games enterprise. In addition, we present a set of projects from various applications in games industry that are using gestural interaction.

Using Mobile Learning Games for Delivery Purposes in Humanities

Games and applications with gamified elements have been used in teaching and learning widely. Gamified applications attract the interest of students and teachers because they assist them to achieve their cognitive and pedagogical purposes. This paper describes a study that explores the use of a gamified learning application designed to introduce students at key stages 3 and 4 (ages 14-15) to ancient Greek Philosophy. The study involves 3 tests and 3 different groups of students and aimed to explore if the application improves students' knowledge and understanding and to compare different styles of subject delivering. This paper presents and discusses in details the results of the first test.

SAR determination and influence of the human head in the radiation of a mobile antenna for two different frequencies

The big proliferation of mobile communication systems has caused an increased concern about the interaction between the human body and the antennas of mobile handsets. In order to study the problem, a multiband antenna was designed, fabricated and measured to operate over two frequency sub bands 900 and 1800 MHz. After that, we simulated the same antenna, but now, in the presence of a human head model to analyze the head's influence. First, the influence of the human head on the radiation efficiency of the antenna has been investigated as a function of the distance between the head and the antenna and with the inclination of the antenna. Furthermore, the relative amount of the electromagnetic power absorbed in the head has been obtained.

Influence of the Human Head in the Radiation of a Mobile Antenna

The big proliferation of mobile communication systems has caused an increased concern about the interaction between the human body and the antennas of mobile handsets. In order to study the problem, a multiband antenna was designed, fabricated and measured to operate over two frequency sub bands 900 and 1800 MHz. After that, we simulated the same antenna, but now, in the presence of a human head model to analyze the head's influence. First, the influence of the human head on the radiation efficiency of the antenna has been investigated as a function of the distance between the head and the antenna and with the inclination of the antenna. Furthermore, the relative amount of the electromagnetic power absorbed in the head has been obtained. In this study the electromagnetic analysis has been performed via FDTD (Finite Difference Time Domain).

O uso do smartphone na avaliação do risco de queda associado ao envelhecimento

Introdução: O declínio do equilíbrio, da força dos membros inferiores e o medo de cair são fatores de risco de queda associados ao envelhecimento e a sua avaliação pode ser realizada pelo teste One Leg Standing (OLS), Sit to Stand (STS) e pela Falls Eficacy Scale (FES), respetivamente. As aplicações para smartphone constituem uma alternativa para a avaliação dos fatores de risco de queda no envelhecimento. Objetivo: Analisar a capacidade de uma aplicação para smartphone na avaliação dos testes STS, OLS e FES. Metodologia: Realizou-se um estudo analítico numa amostra de 27 voluntários com idade ≥ 60 anos. Realizaram-se os testes STS, OLS e a FES (versão iconográfica, apresentada no smartphone). Os dados foram recolhidos simultaneamente por um smartphone e pelo Qualisys Motion Capture Systems associado a uma plataforma de forças. Foi utilizado o r de Pearson ou Spearman para analisar as possíveis correlações. Resultados: No STS obteve-se uma correlação muito forte (rp=0.97) no número de repetições de ciclos Sit Stand Sit (SLS) e forte na duração média do SLS (rp=0.85) e das subfases Sit to Stand (rp=0.69) e Stand to Sit (rp=0.778), com p<0.001. As medidas de inclinação do tronco apresentaram correlações fortes, com exceção do ângulo inicial (p≥0.05). No OLS, verificou-se uma correlação moderada entre o deslocamento do centro de pressão peak to peak médio-lateral (rs=0.45; p=0.017) e antero-posterior (rs=0.39; p=0.046), root mean square médio-lateral (rs=0.39; p=0.046) e antero-posterior (rs=0.46; p=0.017) e área do estatocinesiograma (rs=0.45; p=0.018). Na FES obteve-se uma correlação moderada em três categorias: ‘tomar banho/duche’ (rs=0.49; p=0.010), ‘deitar/levantar da cama (rs=0.43; p=0.024) e ‘chegar aos armários’ (rs=0.38; p=0.050). Conclusão: A aplicação para smartphone parece avaliar corretamente os ciclos e a variação da inclinação do tronco no STS, porém parece necessitar de ser reajustada na FES e na velocidade do deslocamento do centro de pressão, no OLS.

Low Profile Multi-Band Antenna for Mobile Communications

In this paper, the design of low profile antennas by using Electromagnetic Band Gap (EBG) structures is introduced. Taking advantage of the fact that they can behave as Perfect Magnetic Conductor (PMC), it is shown that these structures exhibit dual band in-phase reflection at WLAN (Wireless Local Area Network) bands, the 2.4 GHz and 5.2 GHz bands. These structures are applied to PIFA (Planar Inverted-F Antenna) and the results show that it is possible to obtain low profile PIFA's.

GuideMe: service for consulting, publication and recommendation of touristic locations

Trabalho de Projeto realizado para obtenção do grau de Mestre em Engenharia Informática e de Computadores