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Showing 64,101 through 64,125 of 66,442 results

Vapor Liquid Two Phase Flow and Phase Change

by Sarit Kumar Das Dhiman Chatterjee

This comprehensive textbook highlights features of two phase flows and introduces the readers to flow patterns and flow maps. It covers a wide range of fundamental and complex subjects focusing on phase change processes like boiling, condensation or cavitation, and boiling phenomenon starting from pool boiling curves to heat transfer under nucleate boiling, film, and flow boiling. It also discusses themes such as numerical techniques for solving boiling and condensation as well as equipment used in industry for evaporation, boiling, and condensation. It includes pedagogical aspects such as end-of-chapter problems and worked examples to augment learning and self-testing. This book is a valuable addition for students, researchers, and practicing engineers.

Variability in Human Performance (Human Factors and Ergonomics)

by Thomas J. Smith Robert A. Henning Michael G. Wade Thomas Fisher

Understanding the conditions under which variability in performance may arise, and the processes related to its emergence, gives us insight into the development of techniques for improving the quality of performance.This book introduces a comprehensive framework for understanding human performance variability in terms of how human control of behavior is closely tied to design factors in the performance environment. Empirical evidence, as well as practical examples and application areas, introduced in support of this framework. The book provides suggestions on how individuals, groups, and organizations can significantly reduce variability in human performance that often leads to systems failures.

Variable Frequency Transformers for Large Scale Power Systems Interconnection: Theory and Applications

by Gesong Chen Xiaoxin Zhou Rui Chen

This book is an all-in-one resource on the development and application of variable frequency transformers to power systems and smart grids. It introduces the main technical issues of variable frequency transformers (VFT) systematically, including its basic construction, theory equations, and simulation models. Readers will then gain an in-depth discussion of its control system, operation performance, low frequency power oscillation, and technical economics, before proceeding to practical implementation and future developments. The related concepts of energy revolution, third generation grids, and power system interconnection are discussed as well. The first, comprehensive introduction to variable frequency transformers (VFT) An in-depth look at the construction of VFT, with simulations and applications Demonstrates how to assess the control system and overall system performance Analyses future developments, energy revolution and power system interconnections Variable Frequency Transformers for Large Scale Power Systems is a timely overview of the state of the art for VFT as it is increasingly adopted in smart grids. It is intended for engineers and researchers specializing in power system planning and operation, as well as advanced students and industry professionals of power engineering.

Variable Gain Control and Its Applications in Energy Conversion (Automation and Control Engineering)

by Chenghui Zhang Le Chang Cheng Fu

The variable gain control method is a new construction technique for the control of nonlinear systems. By properly conducting state transformation that depends on the variable gains, the control design problem of nonlinear systems can be transformed into a gain construction problem, thus effectively avoiding the tedious iterative design procedure. Different from the classical backstepping method and forwarding design method, the structure of variable gain control is simpler in the sense that fewer design parameters are required, facilitating the improvement of system control performance. To highlight the learning, research, and promotion of variable gain control, Variable Gain Control and Its Applications in Energy Conversion is written based on the research results of peers at home and abroad and combining our latest research. This book presents innovative technologies for designing variable gain controllers for nonlinear systems. It systematically describes the origin and principles of variable gain control for nonlinear systems, focuses on the controller design and stability analysis, and reflects the latest research. In addition, variable gain control methods applied to energy conversion are also included. Discussion remarks are provided in each chapter highlighting new approaches and contributions to emphasize the novelty of the presented design and analysis methods. In addition, simulation results are given in each chapter to show the effectiveness of these methods. It can be used as a reference book or a textbook for students with some background in feedback control systems. Researchers, graduate students, and engineers in the fields of control, information, renewable energy generation, electrical engineering, mechanical engineering, applied mathematics, and others will benefit from this book.

Variable Geometry Turbine Technology for Marine Gas Turbines

by Jie Gao Qun Zheng Feng Lin Chen Liang Yu Liu

This book starts from the design requirements of variable geometry turbines for marine gas turbines. It systematically and comprehensively introduces the flow mechanism and characteristics of variable geometry turbines, aerodynamic design methods, variable vane turning design methods, structural design technology of the variable vane system, aerodynamic characteristics and reliability test technology for variable geometry turbines, and so on.

The Variable-Order Fractional Calculus of Variations (SpringerBriefs in Applied Sciences and Technology)

by Delfim F. M. Torres Dina Tavares Ricardo Almeida

​The Variable-Order Fractional Calculus of Variations is devoted to the study of fractional operators with variable order and, in particular, variational problems involving variable-order operators. This brief presents a new numerical tool for the solution of differential equations involving Caputo derivatives of fractional variable order. Three Caputo-type fractional operators are considered, and for each one, an approximation formula is obtained in terms of standard (integer-order) derivatives only. Estimations for the error of the approximations are also provided. The contributors consider variational problems that may be subject to one or more constraints, where the functional depends on a combined Caputo derivative of variable fractional order. In particular, they establish necessary optimality conditions of Euler–Lagrange type. As the terminal point in the cost integral is free, as is the terminal state, transversality conditions are also obtained.The Variable-Order Fractional Calculus of Variations is a valuable source of information for researchers in mathematics, physics, engineering, control and optimization; it provides both analytical and numerical methods to deal with variational problems. It is also of interest to academics and postgraduates in these fields, as it solves multiple variational problems subject to one or more constraints in a single brief.

Variable Pitot-Triebwerkseinlässe für kommerzielle Überschallflugzeuge: Konzeptstudie mittels eines Entwicklungsansatzes für sichere Produkte

by Stefan Kazula

In diesem Open-Access-Buch wird gezeigt, wie kommerzielle Überschallflugzeuge die Nachfrage nach einem schnellen, flexiblen und sicheren Transportmittel erfüllen könnten, wenn sie im Vergleich zu früheren Anwendungen eine höhere Nachhaltigkeit durch einen verringerten Kraftstoffverbrauch bieten würden. Dazu könnte eine Luftwiderstandsreduktion ihrer Triebwerke durch die Verwendung variabler Pitot-Einlässe beitragen. Diese finden in der gegenwärtigen reinen Unterschallluftfahrt keine Anwendung, da deren erhöhte Masse sowie die eingeschränkte Zuverlässigkeit und Sicherheit das vorhandene aerodynamische Einsparpotenzial überwiegen. Daher untersucht Stefan Kazula, ob variable Pitot-Einlässe für den Überschallbetrieb bis Mach 1,6 konstruktiv umsetzbar sind, die luftfahrtspezifischen Standards für Sicherheit und Zuverlässigkeit erfüllen können und dabei eine Verbesserung der Nachhaltigkeit ermöglichen. Hierfür wird der Stand der Technik zu variablen Pitot-Einlässen sowie zur Konstruktionsmethodik dargestellt. Zudem wird der zugrundeliegende Konstruktionsansatz zur Erarbeitung eines sicheren und zuverlässigen Konzepts sowie seine Umsetzung vorgestellt.

Variable Renewable Energy and the Electricity Grid

by Jay Apt Paulina Jaramillo

The integration of renewable energy resources into the electricity grid presents an important challenge. This book provides a review and analysis of the technical and policy options available for managing variable energy resources such as wind and solar power. As well as being of value to government and industry policy-makers and planners, the volume also provides a single source for scientists and engineers of the technical knowledge gained during the 4-year RenewElec (renewable electricity) project at Carnegie Mellon University, the University of Vermont, Vermont Law School, and the Van Ness Feldman environmental law firm. The first part of the book discusses the options for large scale integration of variable electric power generation, including issues of predictability, variability, and efficiency. The second part presents the scientific findings of the project. In the final part, the authors undertake a critical review of major quantitative regional and national wind integration studies in the United States. Based on comparisons among these studies, they suggest areas where improvements in methods are warranted in future studies, areas where additional research is needed to facilitate future improvements in wind integration studies and how the research can be put into practice.

Variable Speed AC Drives with Inverter Output Filters

by Jaroslaw Guzinski Haitham Abu-Rub Patryk Strankowski

The advance of variable speed drives systems (VSDs) engineering highlights the need of specific technical guidance provision by electrical machines and drives manufacturers, so that such applications can be properly designed to present advantages in terms of both energy efficiency and expenditure. This book presents problems and solutions related to inverter-fed electrical motors. Practically orientated, the book describes the reasons, theory and analysis of those problems. Various solutions for individual problems are presented together with the complete design process, modelling and simulation examples with MATLAB/Simulink on the companion website. A key focus of Variable Speed AC Drives with Inverter Output Filters is to examine the state variables estimation and motor control structures which have to be modified according to the used solution (filter). In most control systems the structure and parameters are taken into account to make it possible for precise control of the motor. This methodology is able to include modifications and extensions depending on specific control and estimation structures. Highly accessible, this is an invaluable resource for practising R&D engineers in drive companies, power electronics & control engineers and manufacturers of electrical drives. Senior undergraduate and postgraduate students in electronics and control engineering will also find it of value.

Variable-Structure Approaches

by Andreas Rauh Luise Senkel

This edited book aims at presenting current research activities in the field of robust variable-structure systems. The scope equally comprises highlighting novel methodological aspects as well as presenting the use of variable-structure techniques in industrial applications including their efficient implementation on hardware for real-time control. The target audience primarily comprises research experts in the field of control theory and nonlinear dynamics but the book may also be beneficial for graduate students.

Variable-Structure Systems and Sliding-Mode Control: From Theory to Practice (Studies in Systems, Decision and Control #271)

by Martin Horn Leonid Fridman Martin Steinberger

The book covers the latest theoretical results and sophisticated applications in the field of variable-structure systems and sliding-mode control. This book is divided into four parts. Part I discusses new higher-order sliding-mode algorithms, including new homogeneous controllers and differentiators. Part II then explores properties of continuous sliding-mode algorithms, such as saturated feedback control, reaching time, and orbital stability. Part III is focused on the usage of variable-structure systems (VSS) controllers for solving other control problems, for example unmatched disturbances. Finally, Part IV discusses applications of VSS; these include applications within power electronics and vehicle platooning.Variable-structure Systems and Sliding-Mode Control will be of interest to academic researchers, students and practising engineers.

Variable Takt Principle: Mastering Variance with Limitless Product Individualization (Management for Professionals)

by Peter Bebersdorf Arnd Huchzermeier

This book describes how the implementation of variable rate launching in the context of a mixed-model assembly line with unlimited customization flexibility promotes customer-centric production. Variable rate launching (VRL) – as opposed to fixed rate launching (FRL) – eliminates idle time and utility work in mixed-model assembly lines. Even in the context of limitless customization, which runs the risk of concentrated peak workloads and possible longer assembly lines, a variable takt proves to be more economical than a fixed takt. On the technical side, a fixed takt requires both a healthy balance of process times and optimal scheduling to create feasible production schedules, as using average takt does not allow workers enough time to complete their tasks for more complex products. Because the variable takt relies on similar process times for a given product across the entire line for one product, and all products are given exactly the time they need for assembly, optimal series-sequencing and regular task rescheduling can be eliminated. This book is intended as a reference guide for experienced executives in manufacturing and academics teaching operational effectiveness for customer-centric production, and makes extensive references to AGCO Fendt’s modern tractor line in Marktoberdorf, Germany. The book also offers application case studies from companies in related industries such as automotive, electronics, and machine tools. The book’s key message is that variation should not be universally eliminated from manufacturing. As such, the book represents a counterpoint to the philosophy advocated by the Toyota Production System.

Variant Construction from Theoretical Foundation to Applications

by Jeffrey Zheng

This open access book presents theoretical framework and sample applications of variant construction. The first part includes the components variant logic, variant measurements, and variant maps, while the second part covers sample applications such as variation with functions, variant stream ciphers, quantum interference, classical/quantum random sequences, whole DNA sequences, and multiple-valued pulse sequences. Addressing topics ranging from logic and measuring foundation to typical applications and including various illustrated maps, it is a valuable guide for theoretical researchers in discrete mathematics; computing-, quantum- and communication scientists; big data engineers; as well as graduate and upper undergraduate students.

Variation-Aware Adaptive Voltage Scaling for Digital CMOS Circuits

by Martin Wirnshofer

Increasing performance demands in integrated circuits, together with limited energy budgets, force IC designers to find new ways of saving power. One innovative way is the presented adaptive voltage scaling scheme, which tunes the supply voltage according to the present process, voltage and temperature variations as well as aging. The voltage is adapted "on the fly" by means of in-situ delay monitors to exploit unused timing margin, produced by state-of-the-art worst-case designs. This book discusses the design of the enhanced in-situ delay monitors and the implementation of the complete control-loop comprising the monitors, a control-logic and an on-chip voltage regulator. An analytical Markov-based model of the control-loop is derived to analyze its robustness and stability. Variation-Aware Adaptive Voltage Scaling for Digital CMOS Circuits provides an in-depth assessment of the proposed voltage scaling scheme when applied to an arithmetic and an image processing circuit. This book is written for engineers interested in adaptive techniques for low-power CMOS circuits.

Variation-Aware Advanced CMOS Devices and SRAM

by Changhwan Shin

This book provides a comprehensive overview of contemporary issues in complementary metal-oxide semiconductor (CMOS) device design, describing how to overcome process-induced random variations such as line-edge-roughness, random-dopant-fluctuation, and work-function variation, and the applications of novel CMOS devices to cache memory (or Static Random Access Memory, SRAM). The author places emphasis on the physical understanding of process-induced random variation as well as the introduction of novel CMOS device structures and their application to SRAM. The book outlines the technical predicament facing state-of-the-art CMOS technology development, due to the effect of ever-increasing process-induced random/intrinsic variation in transistor performance at the sub-30-nm technology nodes. Therefore, the physical understanding of process-induced random/intrinsic variations and the technical solutions to address these issues plays a key role in new CMOS technology development. This book aims to provide the reader with a deep understanding of the major random variation sources, and the characterization of each random variation source. Furthermore, the book presents various CMOS device designs to surmount the random variation in future CMOS technology, emphasizing the applications to SRAM.

Variation-Aware Design of Custom Integrated Circuits: A Hands-on Field Guide

by Amit Gupta Kristopher Breen Trent Mcconaghy Jeffrey Dyck

This book targets custom IC designers who are encountering variation issues in their designs, especially for modern process nodes at 45nm and below, such as statistical process variations, environmental variations, and layout effects. It teaches them the state-of-the-art in Variation-Aware Design tools, which help the designer to analyze quickly the variation effects, identify the problems, and fix the problems. Furthermore, this book describes the algorithms and algorithm behavior/performance/limitations, which is of use to designers considering these tools, designers using these tools, CAD researchers, and CAD managers.

Variation Tolerant On-Chip Interconnects (Analog Circuits and Signal Processing)

by Ethiopia Enideg Nigussie

This book presents design techniques, analysis and implementation of high performance and power efficient, variation tolerant on-chip interconnects. Given the design paradigm shift to multi-core, interconnect-centric designs and the increase in sources of variability and their impact in sub-100nm technologies, this book will be an invaluable reference for anyone concerned with the design of next generation, high-performance electronics systems.

Variational Analysis and Aerospace Engineering: Mathematical Challenges for Aerospace Design

by Giuseppe Buttazzo Aldo Frediani

This volume consists of papers presented at the Variational Analysis and Aerospace Engineering Workshop II held in Erice, Italy in September 2010 at the International School of Mathematics "Guido Stampacchia". The workshop provided a platform for aerospace engineers and mathematicians (from universities, research centers and industry) to discuss the advanced problems requiring an extensive application of mathematics. The presentations were dedicated to the most advanced subjects in engineering and, in particular to computational fluid dynamics methods, introduction of new materials, optimization in aerodynamics, structural optimization, space missions, flight mechanics, control theory and optimization, variational methods and applications, etc. This book will capture the interest of researchers from both academia and industry.

Variational Analysis and Aerospace Engineering

by Aldo Frediani Bijan Mohammadi Olivier Pironneau Vittorio Cipolla

The Variational Analysis and Aerospace Engineering conference held in Erice, Italy in September 2007 at International School of Mathematics, Guido Stampacchia provided a platform for aerospace engineers and mathematicians to discuss the problems requiring an extensive application of mathematics. This work contains papers presented at the workshop.

A Variational Approach to Nonsmooth Dynamics

by Samir Adly

This brief examines mathematical models in nonsmooth mechanics and nonregular electrical circuits, including evolution variational inequalities, complementarity systems, differential inclusions, second-order dynamics, Lur'e systems and Moreau's sweeping process. The field of nonsmooth dynamics is of great interest to mathematicians, mechanicians, automatic controllers and engineers. The present volume acknowledges this transversality and provides a multidisciplinary view as it outlines fundamental results in nonsmooth dynamics and explains how to use them to study various problems in engineering. In particular, the author explores the question of how to redefine the notion of dynamical systems in light of modern variational and nonsmooth analysis. With the aim of bridging between the communities of applied mathematicians, engineers and researchers in control theory and nonlinear systems, this brief outlines both relevant mathematical proofs and models in unilateral mechanics and electronics.

Variational Methods for Machine Learning with Applications to Deep Networks

by Lucas Pinheiro Cinelli Matheus Araújo Marins Eduardo Antônio Barros da Silva Sérgio Lima Netto

This book provides a straightforward look at the concepts, algorithms and advantages of Bayesian Deep Learning and Deep Generative Models. Starting from the model-based approach to Machine Learning, the authors motivate Probabilistic Graphical Models and show how Bayesian inference naturally lends itself to this framework. The authors present detailed explanations of the main modern algorithms on variational approximations for Bayesian inference in neural networks. Each algorithm of this selected set develops a distinct aspect of the theory. The book builds from the ground-up well-known deep generative models, such as Variational Autoencoder and subsequent theoretical developments. By also exposing the main issues of the algorithms together with different methods to mitigate such issues, the book supplies the necessary knowledge on generative models for the reader to handle a wide range of data types: sequential or not, continuous or not, labelled or not. The book is self-contained, promptly covering all necessary theory so that the reader does not have to search for additional information elsewhere. Offers a concise self-contained resource, covering the basic concepts to the algorithms for Bayesian Deep Learning;Presents Statistical Inference concepts, offering a set of elucidative examples, practical aspects, and pseudo-codes;Every chapter includes hands-on examples and exercises and a website features lecture slides, additional examples, and other support material.

Variational Methods in Image Processing (Chapman & Hall/CRC Mathematical and Computational Imaging Sciences Series)

by Luminita A. Vese Carole Le Guyader

Variational Methods in Image Processing presents the principles, techniques, and applications of variational image processing. The text focuses on variational models, their corresponding Euler-Lagrange equations, and numerical implementations for image processing. It balances traditional computational models with more modern techniques that solve t

Variational Methods with Applications in Science and Engineering

by Kevin W. Cassel

There is a resurgence of applications in which the calculus of variations has direct relevance. In addition to application to solid mechanics and dynamics, it is now being applied in a variety of numerical methods, numerical grid generation, modern physics, various optimization settings and fluid dynamics. Many applications, such as nonlinear optimal control theory applied to continuous systems, have only recently become tractable computationally, with the advent of advanced algorithms and large computer systems. This book reflects the strong connection between calculus of variations and the applications for which variational methods form the fundamental foundation. The mathematical fundamentals of calculus of variations (at least those necessary to pursue applications) is rather compact and is contained in a single chapter of the book. The majority of the text consists of applications of variational calculus for a variety of fields.

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