Bamenda, North West Region, Cameroon : Langaa ; 
Book — xii, 245 pages : illustrations ; 25 cm
The recent history of Africa is characterised by the 'revolution' in information and communication technologies (ICT), specifically in the sector of mobile telephony, which reconsiders the challenges pertaining to identity in African societies. In this book, we follow the manifestation of such dynamic forces in the Hadjeray society in Guera, Tchad, a society that has suffered a history of political violence, mobility and failures. The study shows the role of the Chadian government in the implementation of ICT and explains how government logics have amplified. Through the analysis of the changes in the economic and social spheres, occurring due to mobile telephony, we discover the identity issues that are also informed by the feeling of fear, which is part of the Chadian history of violence. However, the ways in which the Hadjeray adopt this new technology also leave them with a means to escape the logic of violence and disruption. It is mostly a dynamic force that occurs amongst the youth who, by making use of mobile networks, discover another mode of identification, between the ethnic group and the more global identity, and find through it a political voice.
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. (source: Nielsen Book Data) 9783658008079 20160610
Introduction.- Power System Modelling and Analysis Techniques.- The Effects of HVDC Lines on Power System Stability.- Assessing the Robustness of Controllers.- Modal Estimation using the Probabilistic Collocation Method.- Probabilistic Tuning of Damping Controllers.- Conclusions and Future Work.
(source: Nielsen Book Data)
The work in this thesis proposes the innovative use of modern technologies and mathematical techniques to analyse and control future power systems. It exploits new enabling technologies such as Voltage Source Converter High Voltage Direct Current (VSC-HVDC) lines, both single and multi-terminal, and Wide Area Measurement Systems (WAMS) to reduce the risks of instability associated with greater utilisation of modern power systems. New control systems for these technologies have been analysed, and subsequently designed, using advanced probabilistic analysis techniques to ensure that they are robust to the variable and turbulent conditions expected in the future. The advanced probabilistic techniques used in the thesis for both system analysis and controller design represent one of the first such applications in open literature. (source: Nielsen Book Data) 9783319023922 20160612
High-Speed PM Machines: Applications, Trends and Limits
Electromagnetic Modeling of Slotless PM Machines
Structural Aspects of PM Rotors
Rotordynamical Aspects of High-Speed Electrical Machines
Bearings for High-Speed Machines
Design of the High-Speed-Spindle Motor
Control of the Synchronous PM Motor
Conclusions and Recommendations.
There is a growing number of applications that require fast-rotating machines; motivation for this thesis comes from a project in which downsized spindles for micro-machining have been researched. The thesis focuses on analysis and design of high-speed PM machines and uses a practical design of a high-speed spindle drive as a test case. Phenomena, both mechanical and electromagnetic, that take precedence in high-speed permanent magnet machines are identified and systematized. The thesis identifies inherent speed limits of permanent magnet machines and correlates those limits with the basic parameters of the machines. The analytical expression of the limiting quantities does not only impose solid constraints on the machine design, but also creates the way for design optimization leading to the maximum mechanical and/or electromagnetic utilization of the machine. The models and electric-drive concepts developed in the thesis are evaluated in a practical setup. (source: Nielsen Book Data) 9783642334566 20160615
Adaptive embedded systems use at runtime different system configurations in order to calculate output signals for actuators from sensor signals. The set of possible system configurations is huge. The ESP has for instance more than 10^72 possible system configurations. It is thus complex to decide which system configurations shall be implemented. This thesis provides an approach to systematically select at design time a set of system configurations. (source: Nielsen Book Data) 9783839605998 20160618
Power Allocation and Spectrum Sharing in Multi-User, Multi-Channel Systems
Multi-Rate Multicast Service Provisioning
Summary and Future Directions.
This thesis presents a significant contribution to decentralized resource allocation problems with strategic agents. The study focused on three classes of problems arising in communication networks. (C1). Unicast service provisioning in wired networks. (C2). Multi-rate multicast service provisioning in wired networks. (C3). Power allocation and spectrum sharing in multi-user multi-channel wireless communication systems. Problems in (C1) are market problems; problems in (C2) are a combination of markets and public goods; problems in (C3) are public goods. Dr. Kakhbod developed game forms/mechanisms for unicast and multi-rate multicast service provisioning that possess specific properties. First, the allocations corresponding to all Nash equilibria (NE) of the games induced by the mechanisms are optimal solutions of the corresponding centralized allocation problems, where the objective is the maximization of the sum of the agents' utilities. Second, the strategic agents voluntarily participate in the allocation process. Third, the budget is balanced at the allocations corresponding to all NE of the game induced by the mechanism as well as at all other feasible allocations. For the power allocation and spectrum sharing problem, he developed a game form that possesses the second and third properties as detailed above along with a fourth property: the allocations corresponding to all NE of the game induced by the mechanism are Pareto optimal. The thesis contributes to the state of the art of mechanism design theory. In particular, designing efficient mechanisms for the class of problems that are a combination of markets and public goods, for the first time, have been addressed in this thesis. The exposition, although highly rigorous and technical, is elegant and insightful which makes this thesis work easily accessible to those just entering this field and will also be much appreciated by experts in the field. (source: Nielsen Book Data) 9781461463184 20160612
Three dimensional (3D) optical geometries are becoming more common in the literature and lexicon of solar cells. Three Dimensional Solar Cells Based on Optical Confinement Geometries describes and reveals the basic operational nuances of 3D photovoltaics using three standard tools: Equivalent Circuit Models, Ray Tracing Optics in the Cavity, and Absorber Spectral Response. These tools aide in understanding experimental absorption profile and device parameters including Jsc, Voc, Fill Factor, and EQE. These methods also apply to individual optical confinement geometry device, integrated optical confinement geometry device, and hybrid optical confinement geometry device. Additionally, this book discusses the importance of these methods in achieving the goal of high efficiency solar cells and suggests a possible application in large-scale photovoltaics business, like solar farms. (source: Nielsen Book Data) 9781461456988 20160615
Book — 1 online resource (xxxiii, 221 pages) : illustrations
Front cover ; Title page ; Imprint ; Aknowledgments; Index of Contents; List of Figures; List of Tables; List of Symbols; List of Abbreviations and Acronyms; Abstract; Zusammenfassung; Chapter 1; Introduction; 1.1 Elements of the UMTS Technology; 1.2 Transistors with Wide-Bandgap Semiconductors for UMTS; 1.3 Transistor Modeling for Power Amplifier Design; 1.3.1 Proposed Type of Modeling; 1.3.2 Challenges of Modeling Transistors of Wide-Bandgap Semiconductors; 1.3.3 Challenges of Modeling Advanced Large-Size Transistors for High-Power Amplifiers; 1.4 Main Objectives of the Research Work.
1.5 Outline of the ThesisChapter 2; GaN HEMTs for UMTS Power Amplifiers; 2.1 GaN HEMTs Compared with Devices of Other Semiconductors for UMTS Power Amplifiers; 2.1.1 GaN Compared with GaAs, Si and SiC; 2.1.2 GaN Compared with SiC; 2.1.3 GaN HEMTs Compared with LDMOS FETs of Si; 2.2 Physical Structure and Operation of AlGaN/GaN HEMTs; 2.2.1 Basic Layer Structure and Band Diagram; 2.2.2 Formation of the 2DEG; 2.2.3 Functional Description of Advanced Layer Structures; 2.3 Drawbacks of GaN HEMTs and Modeling Challenges; 2.3.1 Charge-Trapping Induced Dispersion.
2.3.2 Parasitic Effects of GaN Devices2.3.3 Self-Heating Effects on GaN Devices; Chapter 3; Device Characterization for Modeling; 3.1 Manufacturers and Technology of the Studied Devices; 3.2 Data Acquisition for Modeling; 3.2.1 Static-DC IV Measurements; 3.2.2 S-Parameter Measurements; 3.2.3 Pulsed-DC Measurements; 3.3 Large-Signal Characterization for Model Verification3.3.1; 3.3.1 Description; 3.3.2 Measurement Setups; Chapter 4; Proposed Strategy for Small-Signal Modeling; 4.1 Small-Signal Electrical Equivalent Circuit; 4.1.1 Physical Meaning of the Circuit Elements.
4.1.2 Physical Meaning of the Extrinsic CapacitanceParameters4.2 Extrinsic Parameter Extraction; 4.2.1 Analysis of the Generation of Capacitance Ratio Values in the TECR Algorithm; 4.2.2 Proposed Generation of Capacitance Ratio Values; 4.2.3 Equation System of Capacitance Parameters in Pinch-Off; 4.2.4 Sweeps of Values on Capacitance Parameters; 4.2.5 Extraction of Extrinsic Resistance Parameters; 4.3 Intrinsic Parameter Extraction; 4.4 Scalability of the Small-Signal Model; 4.4.1 Scaling Rules in Terms of the Gate Electrode Width; 4.4.2 Scaling Rules in Terms of the Gate Electrode Number.
Chapter 5Results of Small-Signal Modeling; 5.1 Results of Extrinsic Parameter Extraction; 5.1.1 Optimal Frequency Range of the Extraction; 5.1.2 Starting and Optimized Values of the Extrinsic Parameters; 5.2 Results of Intrinsic Parameter Extraction; 5.2.1 Frequency and Bias Dependency of Intrinsic Parameters; 5.2.2 Verification Tests with S-Parameters on Active BiasPoints; 5.3 Small-Signal Model Scalability; 5.3.1 Extracted Parameter Values for Different Device Sizes; 5.3.2 Scalability of Model Parameters in Terms of wfg; 5.3.3 Scalability of Model Parameters in Terms of nfg.
3 Magnetoelectric response in triangular lattice antiferromagnets.-
4 Magnetoelectric response in S=1/2 chain helimagnets.-
(source: Nielsen Book Data)
Electric control of magnetic properties, or inversely, magnetic control of dielectric properties in solids, is called a magnetoelectric effect and has long been investigated from the point of view of both fundamental physics and potential application. Magnetic and dielectric properties usually show minimal coupling, but it recently has been discovered that magnetically induced ferroelectricity in some spiral magnets enables remarkably large and versatile magnetoelectric responses. To stabilize such helimagnetism, magnetic frustration (competition between different magnetic interactions) is considered the key. In the present work, two of the most typical frustrated spin systems--triangular lattice antiferromagnets and edge-shared chain magnets--have systematically been investigated. Despite the crystallographic simplicity of target systems, rich magnetoelectric responses are ubiquitously observed. The current results published here offer a useful guideline in the search for new materials with unique magnetoelectric functions, and also provide an important basis for a deeper understanding of magnetoelectric phenomena in more complex systems. (source: Nielsen Book Data) 9784431540908 20160608