Springer us mai 2002 (3 Ergebnisse)

Buch. Zustand: Neu. Neuware - Mechanical stress affects the magnitude of base-emitter voltages of forward biased bipolar transistors. This phenomenon is called the piezojunction effect. The piezojunction effect is the main cause of inaccuracy and drift in integrated temperature sensors and bandgap voltage references. The aim of The Piezojunction Effect in Silicon Integrated Circuits and Sensors is twofold. Firstly, to describe techniques that can reduce the mechanical-stress-induced inaccuracy and long-term instability. Secondly, to show, that the piezojunction effect can be applied for new types of mechanical-sensor structures. During IC fabrication and packaging thermo-mechanical stress is induced, when the packaged chips cool down to the temperature of application. The piezojunction effect is caused by a stress-induced change in the conductivity of the minority-charge carriers, while the piezoresistive effect is caused by a similar effect for the majority-charge carriers. To characterise the anisotropic piezojunction effect, the authors performed systematic investigations over wide ranges of mechanical stress and temperature. The experiments have been performed for various crystal and stress orientations. The experimental results have been used to extract the first- and second-order piezojunction (FOPJ and SOPJ) coefficients for bipolar transistors. It is shown how the knowledge of the piezojunction and piezoresistive coefficients can used to minimize the undesirable mechanical-stress effects on the electrical characteristics of transistors and resistors, respectively. Devices with lower mechanical-stress sensitivity can be found by comparing their piezo-coefficients. The layout of the device can also be optimized to reduce the mechanical-stress sensitivity. As a next step it is shown, how the knowledge of the piezo-effects on device level can be used to predict and to reduce their negative influence on circuit level. This is demonstrated for a number of important basic circuits, including translinear circuits, temperature transducers and bandgap references. Finally, it is shown how the piezojunction effect can be used to fabricate stress-sensing elements. It appears that, in comparison with resistive stress-sensing elements, the piezojunction sensors have the advantage of a smaller size and very low power dissipation.…

Buch. Zustand: Neu. Neuware - Internet heterogeneity is driving a new challenge in application development: adaptive software. Together with the increased Internet capacity and new access technologies, network congestion and the use of older technologies, wireless access, and peer-to-peer networking are increasing the heterogeneity of the Internet. Applications should provide gracefully degraded levels of service when network conditions are poor, and enhanced services when network conditions exceed expectations. Existing adaptive technologies, which are primarily end-to-end or proxy-based and often focus on a single deficient link, can perform poorly in heterogeneous networks. Instead, heterogeneous networks frequently require multiple, coordinated, and distributed remedial actions. Conductor: Distributed Adaptation for Heterogeneous Networks describes a new approach to graceful degradation in the face of network heterogeneity - distributed adaptation - in which adaptive code is deployed at multiple points within a network. The feasibility of this approach is demonstrated by conductor, a middleware framework that enables distributed adaptation of connection-oriented, application-level protocols. By adapting protocols, conductor provides application-transparent adaptation, supporting both existing applications and applications designed with adaptation in mind. Conductor: Distributed Adaptation for Heterogeneous Networks introduces new techniques that enable distributed adaptation, making it automatic, reliable, and secure. In particular, we introduce the notion of semantic segmentation, which maintains exactly-once delivery of the semantic elements of a data stream while allowing the stream to be arbitrarily adapted in transit. We also introduce a secure architecture for automatic adaptor selection, protecting user data from unauthorized adaptation. These techniques are described both in the context of conductor and in the broader context of distributed systems. Finally, this book presents empirical evidence from several case studies indicating that distributed adaptation can allow applications to degrade gracefully in heterogeneous networks, providing a higher quality of service to users than other adaptive techniques. Further, experimental results indicate that the proposed techniques can be employed without excessive cost. Thus, distributed adaptation is both practical and beneficial. Conductor: Distributed Adaptation for Heterogeneous Networks is designed to meet the needs of a professional audience composed of researchers and practitioners in industry and graduate-level students in computer science.…

Buch. Zustand: Neu. Neuware - Physics of Semiconductor Devices covers both basic classic topics such as energy band theory and the gradual-channel model of the MOSFET as well as advanced concepts and devices such as MOSFET short-channel effects, low-dimensional devices and single-electron transistors. Concepts are introduced to the reader in a simple way, often using comparisons to everyday-life experiences such as simple fluid mechanics. They are then explained in depth and mathematical developments are fully described. Physics of Semiconductor Devices contains a list of problems that can be used as homework assignments or can be solved in class to exemplify the theory. Many of these problems make use of Matlab and are aimed at illustrating theoretical concepts in a graphical manner.…