161 research outputs found

    A comparative investigation on the application and performance of Femtocell against Wi-Fi networks in an indoor environment

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    Due to the strenuous demands on the available spectrum and bandwidth, alongside the ever increasing rate at which data traffic is growing and the poor quality of experience QoE) faced with indoor communications, in order for cellular networks to remain dominant in areas pertaining to voice and data services, cellular service providers have to reform their marketing and service delivery strategies together with their overall network rchitecture. To accomplish this leap forward in performance, cellular service operators need to employ a network topology, which makes use of a mix of macrocells and small cells, effectively evolving the network, bringing it closer to the end-­‐user. This investigation explores the use of small cell technology, specifically Femtocell technology in comparison to the already employed Wi-­‐Fi technology as a viable solution to poor indoor communications.The performance evolution is done by comparing key areas in the every day use of Internet communications. These include HTTP testing, RTP testing and VoIP testing. Results are explained and the modes of operation of both technologies are compared

    On the Impact of the Cellular Modem on the Security of Mobile Phones

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    Mobile Kommunikation, Mobiltelefone und Smartphones sind ein wesentlicher Bestandteil unseres tĂ€glichen Lebens geworden. Daher ist es essentiell, dass diese sicher und zuverlĂ€ssig funktionieren. Mobiltelefone und Mobilfunknetze sind hoch komplexe Systeme. Solche Systeme abzusichern ist eine anspruchsvolle Aufgabe. Vorangegangene Arbeiten haben sich meist auf die mobilen EndgerĂ€te, im Speziellen auf die Betriebssysteme sowie Endanwendungen, konzentriert. Die vorliegende Doktorarbeit untersucht einen neuen Weg im Bereich Mobilfunksicherheit. Im Fokus steht das Modem als Schnittstelle zum Mobilfunknetz. Das Mobilfunkmodem ist die Komponente, welche die Funkverbindungzum Mobilfunknetz herstellt und ist nach unserer Auffassung eine der SchlĂŒsselkomponenten bei der Untersuchung und Verbesserung der Mobilfunksicherheit. Mobilfunkmodems sind proprietĂ€r und können nur mit extrem hohem Aufwand untersucht werden. FĂŒr den Einbau zusĂ€tzlicher Sicherungsmaßnahmengilt dasselbe. Aus diesen GrĂŒnden analysiert diese Arbeit nicht das Innenleben eines Modems, sondern dessen Schnittstelle zum mobilen Betriebssystem. In dieser Arbeit untersuchen wir daher die folgende von uns aufgestellte These: Die Sicherheit mobiler EndgerĂ€te sowie der Mobilfunknetze hĂ€ngt direkt mit der Sicherheit der Modemschnittstelle zusammen. Diesen Zusammenhang legen wir anhand von drei Schritten dar. Im ersten Schritt fĂŒhren wir eine Untersuchung der Modemschnittstelle durch. Basierend auf den Ergebnissen der Untersuchung fĂŒhren wir mehrere Sicherheitsanalysen von Short-Message-Service- (SMS) Implementierungen von verschiedenen Telefontypen durch. Im zweiten Schritt untersuchen wir die Möglichkeiten, die sich Schadcode auf mobilen EndgerĂ€ten zu Nutze machen kann. FĂŒr diese Untersuchung entwickeln wir ein Proof-of-Concept-Botnetz, welches mittels des Modems verdeckt kommuniziert. Im dritten Schritt implementieren wir, basierend auf den Ergebnissen der vorangegangenen Schritte, einen Schutzmechanismus zur Absicherung des Modems gegen bösartige Zugriffe. Durch unsere Untersuchungen sind wir zu mehreren Ergebnissen gekommen. Die Software fĂŒr den Empfang von SMS-Nachrichten beinhaltet oftmals (zum Teil kritische) Sicherheitsprobleme. Diese Sicherheitsprobleme haben auch Auswirkungen auf andere Komponenten der EndgerĂ€te. Mit unserem mobilen Botnetz zeigen wir, welche Möglichkeiten Schadcode auf Mobiltelefonen grundsĂ€tzlich zur VerfĂŒgung stehen. Durch den von uns entwickelten Schutzmechanismus der Modemschnittstelle bestĂ€tigen wir unsere anfangs formulierte These. Die Absicherung der Modemschnittstelle verhindert die zuvor prĂ€sentierten Angriffe und zeigt hierdurch, dass die Modemschnittstelle einen entscheidenden Faktor der Mobilfunksicherheit darstellt.Cellular communication and especially mobile handsets are an essential part of our daily lives. Therefore, they need to be secure and work reliably. But mobile handsets and cellular networks are highly complex systems and securing them is a challenging task. Previously, most efforts concentrated on the handsets. These efforts only focused on the mobile phone operating system and applications in order to improve cellular system security. This thesis takes a new path and targets the cellular modem as the route to improve the security of mobile handsets and cellular networks. We target the modem since it is one of the essential parts of a mobile handset. It is the component that provides the radio link to the cellular network. This makes the modem a key element in the task to secure mobile phones. But cellular modems are proprietary and closed systems that cannot be easily analyzed in the full or even modified to improve security. Therefore, this thesis investigates the security of the cellular modem at its border to the mobile phone operating system. We suspect that the security of mobile handsets and cellular network strongly depends on the security of the modem interface. This is our hypothesis, which we seek to prove in this work. We solve this in three steps. In the first step, we analyze the interaction between the cellular modem and the other parts of a modern mobile phone. Based on the analysis we develop two novel vulnerability analysis methods. Using this methods we conduct vulnerability analysis of the Short Message Service implementations on various mobile phones. In the second step, we investigate the possible capabilities that malware has through unhindered access to the cellular modem. For this, we develop a cellular botnet where the bots utilize the modem for stealthy communication. In the third step, we use the results from the previous analysis steps to improve the security at the cellular modem interface. In our analysis step, we abused the cellular modem for vulnerability analysis.We discovered several security and reliability issues in the telephony softwares tack of common mobile phones. Using our cellular botnet implementation, we show how malware can abuse access to the cellular modem interface for various kinds of unwanted activities. In the final step, we show that through improving the security at the cellular modem interface the security of mobile handsets as well as the security of cellular networks can be increased. Throughout this thesis we show that the cellular modem has a significant impact on mobile phone security

    Generic and Parameterizable Service for Remote Configuration of Mobile Phones Using Near Field Communication

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    Os serviços nos nossos dispositivos mĂłveis tĂȘm aumentado em nĂșmero e complexidade nos Ășltimos anos. Utilizadores menos experientes sentem dificuldade em tirar total partido destes serviços. De forma a atenuar este problema, Ă© necessĂĄrio encontrar novas e inovadoras formas que permitam assistir o utilizador no processo de configuração. Para alĂ©m disso, vivemos numa sociedade do imediato. As pessoas querem que o acesso aos recursos seja rĂĄpido, simples e seguro. É tambĂ©m sabido que grande parte dos utilizadores sĂŁo leigos no que diz respeito Ă  utilização de funcionalidades avançadas dos dispositivos mĂłveis, o que resulta em alguma inĂ©rcia no uso de certas aplicaçÔes e funcionalidades.O Near Field Communication oferece uma oportunidade Ășnica para introduzir novos paradigmas de negĂłcio no que diz respeito Ă  interação e facilidade de utilização. Esta dissertação especifica um serviço genĂ©rico e parametrizĂĄvel para a configuração remota de dispositivos.Mobile services have increased both in number and complexity in the past few years. This means that in order to get the most out of these services, less experienced users will have a hard time configuring them by hand. To address this issue, we must find new and innovative solutions to assist the user in this process. Furthermore, we live in a society of the immediate. Everyone wants access to resources to be fast, simple and secure. It is also known that most of the users are laymen when referring to advanced configuration of mobile phone, resulting in some inertia in the use of applications and functionalities.Near Field Communication (NFC) provides an unique opportunity to introduce new business paradigms in terms of interaction and ease of use. This dissertation specifies a generic and parameterizable service for remote configuration of mobile devices using Near Field Communication, which requires minimal user intervention

    Framework for the Integration of Mobile Device Features in PLM

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    Currently, companies have covered their business processes with stationary workstations while mobile business applications have limited relevance. Companies can cover their overall business processes more time-efficiently and cost-effectively when they integrate mobile users in workflows using mobile device features. The objective is a framework that can be used to model and control business applications for PLM processes using mobile device features to allow a totally new user experience

    Email filtering and mobile delivery

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    Thesis (S.M.)--Massachusetts Institute of Technology, School of Architecture and Planning, Program in Media Arts and Sciences, 1999.Includes bibliographical references (p. 121-122).This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.This thesis is about delivering electronic messages. Active Messenger, a software system, makes it easier and more efficient. Today, there are a multitude of communication devices and channels available to exchange messages. However, each of these devices and channels has different capabilities. Additionally, the location of a user is often unknown. Current systems that decide where to send a message in a heterogeneous communication environment are complicated to customize and inefficient. The Active Messenger improves this situation. The Active Messenger is an agent that is capable of taking several steps over time to guarantee the delivery of a message, trying multiple channels and awaiting possible user reactions. It infers the location of the user by looking at her communication history and communication behavior. If a message arrives in the user's inbox, the Active Messenger decides if it is important by looking at user-specified rules, as well as correlating it with recent messages, the user's calendar, and her address book. Depending on the importance of the message and the inferred location of the user, the Active Messenger decides where to send the message, possibly to several devices in turn, monitoring the reactions of the user and the success of the delivery. For example, if a reply comes back shortly after a message is sent to a two-way capable device, the Active Messenger assumes that the user has read the message. If the primary communication device used provides no back-channel information, the Active Messenger infers whether the message has been read by monitoring other channels shortly thereafter. Depending on the status of the sender defined by the user, the Active Messenger may also give feedback to the sender about the user's location and communication behavior. The goal is to make the Active Messenger easily configurable. This thesis shows a first step towards an integration of the available communication channels.by Stefan Johannes Walter Marti.S.M

    I-centric User Interaction

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    Die Vision I-centric Communications bedeutet, einen uneingeschrĂ€nkten Blick auf das menschliche Kommunikationsverhalten zu werfen, um Kommunikationssysteme entsprechend daran angepasst zu entwickeln. Diese Vision definiert einen benutzerorientierten Ansatz zur Erstellung von Diensten und Anwendungen. Dies setzt zunĂ€chst eine Analyse der Benutzeranforderungen voraus, um geeignete Systeme und Dienste zu entwerfen. Anstatt Technologie-fokussierte Lösungen ohne jegliche Anpassung an die jeweiligen Personen anzubieten, sollte ein I-centric System seine Dienste ohne sichtbare technische Details und unter BerĂŒcksichtigung von BenutzerprĂ€ferenzen sowie der Benutzerumgebung darbieten. Der Vision von I-centric Communications folgend, stellt die vorliegende Arbeit einen Ansatz zur Realisierung der Idee von I-centric User Interaction vor. Dieser Ansatz erweitert und vervollstĂ€ndigt die Vision durch verbesserte BenutzerinteraktionsfĂ€higkeiten. Diese Dissertation zeigt, dass es möglich ist, Kommunikationssysteme zu realisieren, die die Interaktion zwischen Benutzern und Diensten ohne EinschrĂ€nkung auf bestimmte Technologien fĂŒr Benutzerschnittstellen sowie in personalisierter und umgebungsberĂŒcksichtigende Art und Weise unterstĂŒtzen. Derartig verbesserte Benutzerinteraktion wird die Akzeptanz und die Benutzung von Diensten erhöhen. Einerseits soll die Benutzerinteraktion verschiedene Arten von Technologien fĂŒr Benutzerschnittstellen unterstĂŒtzen, durch die die GerĂ€te-UnabhĂ€ngigkeit und der stĂ€ndige Zugang zu den Diensten ermöglicht werden. Entsprechend dem aktuellem Kontext und der Absicht können die Benutzer die bevorzugte und geeignete Art der Interaktion wĂ€hlen. Andererseits soll die Interaktion selbst den BenutzerprĂ€ferenzen sowie der jeweiligen Umgebung angepasst werden. Dementsprechend diskutiert die vorliegende Arbeit diese unterschiedlichen Problembereiche, identifiziert die notwendigen Funktionen und bietet entsprechende LösungsansĂ€tze jeweils. Die Arbeit prĂ€sentiert und analysiert zunĂ€chst die Vision I-centric Communications mit Hinblick auf den Aspekt der Benutzerinteraktion. Basierend auf den identifizierten Anforderungen wurde ein Ansatz zur Realisierung von I-centric User Interaction entwickelt. Dieser Ansatz, der in dieser Arbeit vorgestellt wird, spezifiziert ein Service Adaptation Framework und einzelne Modelle fĂŒr Generische Benutzerinteraktion , fĂŒr Personalisierung sowie fĂŒr Ambient Awareness , die sich jeweils auf die identifizierten Problembereiche konzentrieren. Abschließend prĂ€sentiert die vorliegende Arbeit Ergebnisse einer prototypischen Realisierung des dargelegten Ansatzes. Die Ergebnisse demonstrieren die Einsetzbarkeit der entwickelten Konzepte und die ErfĂŒllung der Vision von I-centric User Interaction . Die Forschungsarbeit im Bereich I-centric Communications wurde in Kooperation zwischen dem Lehrstuhl fĂŒr Offene Kommunikationssysteme (OKS) der Technischen UniversitĂ€t Berlin (TUB) und dem Fraunhofer Institut FOKUS durchgefĂŒhrt. Die Vision sowie das Referenzmodell fĂŒr I-centric Communications , die in der vorliegenden Arbeit vorgestellt werden, sind Ergebnisse dieser Kooperation. Die Forschungsschwerpunkte der Kooperation zwischen TUB und FOKUS waren das Generelle Modell fĂŒr I-centric Dienste , die Dienstplattform fĂŒr I-centric Dienste sowie ein Ansatz zur Interaktion zwischen Nutzern und I-centric Dienste . Die vorliegende Arbeit konzentriert sich auf den Ansatz I-centric User Interaction , der die Interaktion zwischen Nutzern und den Diensten betrachtet. Die Aspekte der I-centric Dienste werden in der vorliegenden Arbeit nicht betrachtet. Diese Aspekte wurden in einer zweiten Dissertation von Stefan Arbanowski, Fraunhofer FOKUS, analysiert und ausgearbeitet. Die Ergebnisse dieser Arbeit wurden in verschiedenen nationalen und internationalen Forschungsprojekten (BMBF LiveFutura, BMBF PI-AVIda, BMBF VHE-UD, IST WSI, IST WWRI), Standardisierungsgremien (OMG, WWRF), Konferenzpapieren sowie Zeitschriften eingebracht, um die Vision von I-centric Communications einem grĂ¶ĂŸeren Auditorium vorzustellen.The vision of I-centric Communications means to take an unlimited look at human communication behavior and to adapt the activities of communication systems to it. This vision defines a user-centered approach for the realization of services and applications. It requires to start analyzing user demands to design suitable systems and services. Instead of just providing technology-focused solutions without any adaptation to individuals, an I-centric system should provide services hiding technical details and considering the individual s preferences as well as the individual s environment. Following the vision of I-centric Communications, this thesis introduces an approach to realize I-centric User Interaction. This approach enhances and completes the vision by providing advanced user interaction capabilities. It answers the question whether it is possible to realize a communication system, which allows the interaction between user and services without any restriction to specific user interface technologies and in a personalized as well as ambient aware manner. Such enhanced user interaction will lead to a higher acceptance and increased usage of services. On the one hand, the user interaction shall support different kinds of user interface technologies enabling Device Independence and ubiquitous access to the services. According to their current context and intended action, users can select the preferred and suitable way of interaction. On the other hand, the user interaction shall be adapted to the user s preferences and to the user s environment. Accordingly, this work discusses these different areas of concern, identifies necessary functions, and provides suitable solutions for each. First, the thesis introduces and analyses the vision of I-centric Communications with special regard to the aspect of user interaction. Based on the identified requirements and areas of concern, an approach to realize I-centric User Interaction was developed. The approach, presented in this thesis, specifies a Service Adaptation Framework and individual models for Personalization, for Ambient Awareness, and for Generic User Interaction focusing on the respective areas of concern. Finally, the thesis illustrates the results from the prototypical implementation of the presented approach, which has been pursued in several projects in parallel. These results demonstrate the applicability of the developed concepts and the fulfillment of the vision of I-centric User Interaction. The work in the area of I-centric Communications was carried out in cooperation of the Department for Open Communication Systems (OKS) at the Technical University Berlin (TUB) and the Fraunhofer Institute FOKUS. The vision and the reference model for I-centric Communications, introduced in this thesis, are results of this cooperation. The main research directions for the cooperation between TUB and FOKUS have been a general model for I-centric services, the service platform for I-centric services, and an approach for the interaction of users with I-centric services. This thesis focuses on an approach for I-centric User Interaction. The general aspects of I-centric services as defined by the vision are out of scope of this thesis. Nevertheless, these aspects have been analyzed by Stefan Arbanowski, researcher at Fraunhofer FOKUS, in a second PhD thesis in parallel. The results of this work have been contributed to different national and international projects (BMBF LiveFutura, BMBF PI-AVIda, BMBF VHE-UD, IST WSI, IST WWRI), standardization bodies (OMG, WWRF), conferences papers, and journals by introducing the vision of I-centric Communications to a larger auditorium, and by exploiting parts of the developed I-centric systems
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