Advanced Studies Mobile Research Center Bremen – serie
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16 produkter
16 produkter
Häftad, Engelska, 2012
549 kr
Skickas inom 10-15 vardagar
The key to a successful future mobile communication system lies in the design of its radio scheduler. One of the key challenges of the radio scheduler is how to provide the right balance between Quality of Service (QoS) guarantees and the overall system performance. Yasir Zaki proposes innovative solutions for the design of the Long Term Evolution (LTE) radio scheduler and presents several LTE radio scheduler analytical models that can be used as efficient tools for radio dimensioning. The author also introduces a novel wireless network virtualization framework and highlights the potential gains of using this framework for the future network operators. This framework enables the operators to share their resources and reduce their cost, thus achieving a better overall system performance and radio resource utilization.
Del 2 - Advanced Studies Mobile Research Center Bremen
Mobile Schutzassistenz
Grundlagen, Entwurfsmethodik, Gestaltanforderungen
Häftad, Tyska, 2012
817 kr
Skickas inom 10-15 vardagar
Persönliche Schutzausrüstung und mit ihr die Schutzbekleidung sind im Wandel begriffen. Miniaturisierte, Textil-integrierte Computer eröffnen neue Möglichkeiten der Funktionsgestaltung. Mit kontextsensitiven und aktorischen Funktionen ausgestattet und zu Sensornetzwerken verknüpft, übernimmt die intelligente Schutzbekleidung – ähnlich einem Fahrerassistenzsystem in einem Automobil – die Beobachtung und Signalisierung von Gefährdungen in einem Arbeitsumfeld. Christof Breckenfelder entwickelt einen methodischen Ansatz für den Entwurf dieser mobilen Schutzassistenzsysteme. Die Vorteile der soziologisch-technischen Implikationen von Bekleidung werden am Beispiel eines intelligenten Feuerwehrschutzhandschuhs herausgearbeitet und validiert.
Häftad, Engelska, 2014
549 kr
Skickas inom 10-15 vardagar
In recent years, originally static and single purpose Wireless Sensor Networks have moved towards applications that need support for mobility and multiple purposes. These heterogeneous applications and services demand for a framework which distributes and discovers the various services, so that other pieces of equipment can use them. Markus Becker studies, extends, analytically models, simulates and employs the so called Trickle algorithm in measurements in a Wireless Sensor Network test bed for the service distribution. The obtained results apply to the application of the Trickle algorithm at lower protocol layers, e.g. for routing, as well. Given application delay requirements, the author derives the realizable distances and number of nodes for two network topologies from the 95 percentiles obtained by simulation.
Häftad, Engelska, 2016
565 kr
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Max Gath presents a multiagent system for the optimization of transport logistics in highly complex and dynamic domains. The described solution dynamically optimizes processes and provides a high flexibility, scalability, robustness, and adaptability to individual customer demands. The experimental evaluation points out the effectiveness and efficiency by using the example of commonly applied benchmarks as well as two case studies in groupage traffic and in courier, express, and parcel services with same-day deliveries. Both case studies were performed with leading transport companies in Germany. The results demonstrate that the multiagent-based solution satisfies domain-specific requirements and exploits high optimization potential in real-world processes.
Häftad, Engelska, 2016
549 kr
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Thomas Pötsch investigates the channel properties of cellular networks and analyzes the effects that cause inefficient performance of legacy congestion control protocols, such as TCP and its variants, on cellular networks. Inspired by the findings, a novel delay-based congestion control protocol called Verus is proposed and evaluated across a variety of network scenarios. Furthermore, the author develops a stochastic two-dimensional discrete-time Markov modeling approach that dramatically simplifies the understanding of delay-based congestion control protocols.
Häftad, Engelska, 2018
565 kr
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This book emerged out of research done during the period between 2004 and 2016 on the topic of mobile and wearable computing. It did not solely focus on technical solutions and the search for a general approach but also on the question how people can live with this technology. Thus social and organizational aspects were also part of the research. The findings demonstrate the opportunities of serious games and reveal the need of clinical studies when targeting at solutions that are to become part of any kind of therapy. The result is a comprehensive presentation of research findings covering different important aspects in the domain of wearable and pervasive computing for a better life.
Häftad, Engelska, 2008
1 091 kr
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For the simulation of stochastic systems, those techniques are essential which are able to speed up the simulation, i.e. the equivalent of increasing the accuracy that can be reached within a given run-time, especially with a focus on rare events.Eugen Lamers explains the principle of simulation speed-up in general, demonstrates the technique RESTART for the simulation of rare events, and addresses its efficiency on distributed systems. Due to the character of RESTART, the efficiency is limited by the high communication overhead. The author introduces the Short-Term Dynamic Simulation concept, developed for the planning of mobile radio networks, which enables fast state space coverage along with the consideration of dynamic aspects. He analyses the speed-up potential on a theoretical basis with analytically solvable Markov models for different utilisations. With realistic models for UMTS network planning he shows that the evaluation of dynamic performance measures benefits from the Short-Term Dynamic Simulation technique.
Häftad, Engelska, 2008
1 091 kr
Skickas inom 10-15 vardagar
The universalmobiletelecommunications system (UMTS) is a technical standard for a third generation (3G) telecommunication system. UMTS provides data rates more than three 1 times higher than its second generation (2G) predecessors. The increased speed en ables, for example, video calls, music downloads, or fast web surfing. The technology is already widely available. In 2007, a total of 166 commercial UMTS radio networks are operational in 66 countries covering all continents (UMTS Forum, 20°7), and there are already more than 100 million UMTS subscribers (3GToday. com, 2007; UMTS Forum, 2006). The market for mobile telecommunication is, however, increasingly competi tive, therefore operators need to invest effectively. In Western Europe, mobile phone penetration has reached 100 % in 2006 and the average revenue per customer is de clining (3G. co. uk, 2007). Besides spectrum license fees, the main cost driver is network infrastructure (Ellingeret al. , 2002). Radio network planning can cut operational and capital expenditure by up to 30 % (Dehghan, 2005). Good radio network planning is difficult for UMTS, because its radio interface is more complex than anything used at mass-market level before (Dehghan, 2005). Con nections are separated via codes; they share the same frequency band and are thus subject to interference. On each link, the system constantly regulates the amount of generated interference to a minimum via a power-control feedback loop.
Häftad, Engelska, 2010
1 123 kr
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Growing demands of wireless local area communication are prominent for many day-to-day activities. Applications such as multimedia or VoIP which rely on tight quality-of-service (QoS) support are widely used. In order to handle these applications properly, the data transmission over radio channels should be enhanced by means of spectrum management.Andreas Könsgen describes two major areas of spectrum management, namely the coordination of neighbouring networks with overlapping ranges by controlling different transmission parameters and the channel allocation by the base station inside a radio cell using a cross-layer approach. Theoretical analyses and simulations demonstrate the usage of these methods and show the QoS enhancements which can be achieved. Finally, the author discusses the practical meaning of spectrum management and presents an outlook for future enhancements.
Häftad, Engelska, 2010
1 123 kr
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Routing in dynamically changing networks is a challenge, especially when the current context, usually consisting of multiple criteria, is used as a quality measure and decision metric.Bernd-Ludwig Wenning presents a context-based routing framework which can be applied to routing in different application domains. The routing framework includes the signaling as well as a decision system that is applied for route selection. The author chooses two application domains to evaluate the routing framework: logistic transportation networks and wireless sensor networks. He shows that this routing framework can be considered as a basis for future research in the area of context-based routing, as it opens manifold directions for further applications and enhancements.
Häftad, Engelska, 2011
1 091 kr
Skickas inom 10-15 vardagar
An important means for improving the cost-efficiency in modern mobile radio networks is to dimension the radio access network carefully.Xi Li presents innovative analytical models and algorithms for the dimensioning of the 3G UMTS Radio Access Network (RAN). The proposed analytical models allow efficient and accurate dimensioning for different evolutions of UMTS radio access technologies. The author validates the analytical models by simulations using developed UMTS system simulation models. All presented analytical dimensioning models are implemented into a commercial dimensioning tool. This dimensioning tool is used to help the 3G UMTS network operators to optimize their network infrastructure in order to reduce network costs while still being able to offer desired Quality of Service.
Häftad, Tyska, 2011
706 kr
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Navigation ist eine der fundamentalsten Aufgaben eines natürlichen kognitiven Systems und wird selbst von einfachen Organismen auf der Basis minimaler räumlicher Informationen und geringer Verarbeitungskapazität mit erstaunlicher Robustheit und Präzision gelöst. Thomas Wagner untersucht die grundlegende Frage, welche räumlichen Informationen zur Navigation benötigt werden, während aktuelle klassische Ansätze zur Navigation darauf fokussieren, ein Maximum an Informationen zu verarbeiten. Der Autor zeigt formal wie auch in der Simulation, dass bei geeigneter Modellierung bereits reines egozentrisches Reihenfolgewissen (Ordnungsinformationen) ausreicht, um komplexe Navigationsleistungen robust zu vollbringen.
Häftad, Engelska, 2011
549 kr
Skickas inom 10-15 vardagar
Design and development of a cost-effective mobile broadband wireless access network is a key challenge for many mobile network operators. Overdimensioning or underdimensioning of the access network results in additional costs and a reduction of the customer satisfaction, respectively. Thushara Weerawardane introduces new transport technologies and features for High Speed Packet Access (HSPA) and Long-Term Evolution (LTE) networks. He proposes novel adaptive flow control and enhanced congestion control algorithms and develops corresponding analytical models. These models are based on Markov chains and can be performed for faster analysis evaluation compared to long lasting detailed simulations. Both simulation and analytical models provide optimum network performance and reliable guaranteed quality of standard for the end users during congestion in the transport network. Further, the author investigates and analyzes the LTE transport network performance by introducing novel traffic differentiation models and buffer management techniques during intra-LTE handovers.
Häftad, Engelska, 2007
549 kr
Skickas inom 10-15 vardagar
When joining Siemens in 2001, I also extended my research interest towards radio net work planning methodologies. This area of research brought together my personal interest in mobile communications and in the design of ef?cient algorithms and data structures. Between 2001 and 2003, I participated in the EU project Momentum, which was target ing the performance evaluation and optimization of UMTS radio networks. In this project my main focus was on Monte Carlo snapshot techniques, shortly after I broadened my research scope towards network optimization techniques. Both constitute the basis of this thesis. Later I got the chance to bring in the ideas and methods of my thesis into a Siemens internal planning and optimization tool, the development of which I guided over the last two years. First of all I would like to thank Professor Dr. Carmelita Görg for supervising this thesis, for her guidance, and her encouragement. I very much appreciate that she although I, as an external Ph. D. student, was not part of her department at the University of Bremen was always very open for discussions and provided me with a large amount of useful suggestions over the past years. I without a doubt greatly bene?ted from this, both in my scienti?c work and personally. I am also deeply grateful for the comments and suggestions by Professor Dr. Thomas Kürner, who is also the second examiner of this thesis.
Häftad, Tyska, 2007
873 kr
Skickas inom 10-15 vardagar
Häftad, Engelska, 2008
565 kr
Skickas inom 10-15 vardagar
Looking at mobile solutions or wearable computing, it immediately becomes apparent that their user interfaces call for di?erent solutions than the desktop paradigm. This is not only due to the very small size of the displays but also predominantly to the need for a much stronger dependency on the applications. In addition, they feature a use of environmental sensors which has never been seen before enabling applications to run in an Ambient Intelligence Environment. This development requires new solutions and constitutes new research questions. With this book, Dr. Witt contributes to the goal of including mobile and wearable interfaces into a proper development process again: He develops a systematical approach for the development of mobile and wearable user interfaces that can be embedded in standard development processes, and which can also be evaluated during this process. Furthermore, he also describes the architecture and implementation of the WUI, a We- able User Interface Toolkit, which provides the necessary levels of abstraction to allow the programmers of mobile and wearable solutions to easily implement novel solutions in an almost standardized way. These results are based on a solid theoretical foundation and thorough state-of-the-art research. The evaluation of mobile and wearable user interfaces which usually combine a primary manual task with computer assistance is developed as an especially clever ga- like process: Dr. Witt uses the ”hot wire” game to combine all relevant aspects for a proper evaluation.