springer us okt 1995 (58 risultati)

Buch. Condizione: Neu. Neuware - Post-Keynesian Economic Theory explores and develops several areas of post- Keynesian economics most in need of additional fundamental research, including: a monetary theory of production; post-Keynesian price theory; international economics; labor economics; financing aggregate demands; and the liquidity preference theory of interest. The book presents a constructive post-Keynesian critique of contemporary macroeconomic conceptualization and practice. It illustrates the illusory character of the search for unique, determinate results in the problems of macroeconomics and clearly demonstrates the complexity and resulting richness of meaningful economic theory.

Buch. Condizione: Neu. Neuware - As its title implies, Advances in Multicriteria Analysis presents the most recent developments in multicriteria analysis and in some of its principal areas of application, including marketing, research and development evaluation, financial planning, and medicine. Special attention is paid to the interaction between multicriteria analysis, decision support systems and preference modeling. The five sections of the book cover: methodology; problem structuring; utility assessment; multi-objective optimisation; real world applications. Audience: Researchers and professionals who are operations researchers, management scientists, computer scientists, statisticians, decision analysts, marketing managers and financial analysts.

Buch. Condizione: Neu. Neuware - High-Performance Digital VLSI Circuit Design is the first book devoted entirely to the design of digital high-performance VLSI circuits. CMOS, BiCMOS and bipolar ciruits are covered in depth, including state-of-the-art circuit structures. Recent advances in both the computer and telecommunications industries demand high-performance VLSI digital circuits. Digital processing of signals demands high-speed circuit techniques for the GHz range. The design of such circuits represents a great challenge; one that is amplified when the power supply is scaled down to 3.3 V. Moreover, the requirements of low-power/high-performance circuits adds an extra dimension to the design of such circuits. High-Performance Digital VLSI Circuit Design is a self-contained text, introducing the subject of high-performance VLSI circuit design and explaining the speed/power tradeoffs. The first few chapters of the book discuss the necessary background material in the area of device design and device modeling, respectively. High-performance CMOS circuits are then covered, especially the new all-N-logic dynamic circuits. Propagation delay times of high-speed bipolar CML and ECL are developed analytically to give a thorough understanding of various interacting process, device and circuit parameters. High-current phenomena of bipolar devices are also addressed as these devices typically operate at maximum currents for limited device area. Different, new, high-performance BiCMOS circuits are presented and compared to their conventional counterparts. These new circuits find direct applications in the areas of high-speed adders, frequency dividers, sense amplifiers, level-shifters, input/output clock buffers and PLLs. The book concludes with a few system application examples of digital high-performance VLSI circuits. Audience: A vital reference for practicing IC designers. Can be used as a text for graduate and senior undergraduate students in the area.

Buch. Condizione: Neu. Neuware - Business process re-engineering tools offer techniques to model the enterprise and identify opportunities to make change. This book examines the approaches, tools and techniques which support redesign of the enterprise to achieve world class performance.

Buch. Condizione: Neu. Neuware - Language, Compilers and Run-time Systems for Scalable Computers contains 20 articles based on presentations given at the third workshop of the same title, and 13 extended abstracts from the poster session. Starting with new developments in classical problems of parallel compiler design, such as dependence analysis and an exploration of loop parallelism, the book goes on to address the issues of compiler strategy for specific architectures and programming environments. Several chapters investigate support for multi-threading, object orientation, irregular computation, locality enhancement, and communication optimization. Issues of the interface between language and operating system support are also discussed. Finally, the load balance issues are discussed in different contexts, including sparse matrix computation and iteratively balanced adaptive solvers for partial differential equations. Some additional topics are also discussed in the extended abstracts. Each chapter provides a bibliography of relevant papers and the book can thus be used as a reference to the most up-to-date research in parallel software engineering.

Buch. Condizione: Neu. Neuware - Ken Gilleo's Polymer Thick Film provides you with all the essential concepts, process descriptions, performance data, and general information you will need to reach your own conclusions. The focus will be on polymer thick film's major subsets, which include conductive inks, printed resistors, dielectric films or pastes, and polymer assembly material.

Buch. Condizione: Neu. Neuware - Telecommunications today is in the midst of far-reaching changes due to rapid development of new technologies, services and social evolution. This is the first book to model the process of change in telecommunications, including all of the relevant factors. The approach is practical and responsible, based on hard facts and tested models. It deals with fundamental issues affecting the future development of telecoms and its impact on societies and presents views which some will find radical.

Buch. Condizione: Neu. Neuware - Document Processing and Retrieval: TEXPROS focuses on the design and implementation of a personal, customizable office information and document processing system called TEXPROS (a TEXt PROcessing System). TEXPROS is a personal, intelligent office information and document processing system for text-oriented documents. This system supports the storage, classification, categorization, retrieval and reproduction of documents, as well as extracting, browsing, retrieving and synthesizing information from a variety of documents. When using TEXPROS in a multi-user or distributed environment, it requires specific protocols for extracting, storing, transmitting and exchanging information. The authors have used a variety of techniques to implement TEXPROS, such as Object-Oriented Programming, Tcl/Tk, X-Windows, etc. The system can be used for many different purposes in many different applications, such as digital libraries, software documentation and information delivery. Audience: Provides in-depth, state-of-the-art coverage of information processing and retrieval, and documentation for such professionals as database specialists, information systems and software developers, and information providers.

Buch. Condizione: Neu. Neuware - A Paradigm for Decentralized Process Modeling presents a novel approach to decentralized process modeling that combines both trends and suggests a paradigm for decentralized PCEs, supporting concerted efforts among geographically-dispersed teams - each local individual or team with its own autonomous process - with emphasis on flexible control over the degree of collaboration versus autonomy provided. A key guideline in this approach is to supply abstraction mechanisms whereby pre-existing processes (or workflows) can be encapsulated and retain security of their internal artifacts and status data, while agreeing with other processes on formal interfaces through which all their interactions are conducted on intentionally shared information. This book is primarily intended to provide an in-depth discussion of decentralized process modeling and enactment technology, covering both high-level concepts and a full-blown realization of these concepts in a concrete system. Either the whole book or selected chapters could be used in a graduate course on software engineering, software process, or software development environments, or even for a course on workflow systems outside computer science (e.g., in a classical engineering department for engineering design, or in a business school for business practices or enterprise-wide management, or in the medical informatics department of a health science institution concerned with computer-assistance for managed care). Selected portions of the book, such as section 2.2 on Marvel, could also be employed as a case study in advanced undergraduate software engineering courses. A Paradigm for Decentralized Process Modeling is a valuable resource for both researchers and practitioners, particularly in software engineering, software development environments, and software process and workflow management, but also in electrical, mechanical, civil and other areas of engineering which have analogous needs for design processes, environmental support and concurrent engineering, and beyond to private and public sector workflow management and control, groupware support, and heterogeneous distributed systems in general.

Buch. Condizione: Neu. Neuware - This is the sixth conference in the series which started in 1981 in Paris, followed by conferences held in Zurich (1984), Rio de Janeirio (1987), Barcelona (1991), and Raleigh (1993). The main objective of this IFIP conference series is to provide a platform for the exchange of recent and original contributions in communications systems in the areas of performance analysis, architectures, and applications. There are many exiciting trends and developments in the communications industry, several of which are related to advances in Asynchronous Transfer Mode (ATM), multimedia services, and high speed protocols. It is commonly believed in the communications industry that ATM represents the next generation of networking. Yet, there are a number of issues that has been worked on in various standards bodies, government and industry research and development labs, and universities towards enabling high speed networks in general and ATM networks in particular. Reflecting these trends, the technical program of the Sixth IFIP W.G. 6.3 Conference on Performance of Computer Networks consists of papers addressing a wide range of technical challenges and proposing various state of the art solutions to a subset of them. The program includes 25 papers selected by the program committee out of 57 papers submitted.

Buch. Condizione: Neu. Neuware - Video and Image Processing in Multimedia Systems treats a number of critical topics in multimedia systems, with respect to image and video processing techniques and their implementations. These techniques include: Image and video compression techniques and standards, and Image and video indexing and retrieval techniques. Video and Image Processing in Multimedia Systems is divided into three parts. Part I serves as an introduction to multimedia systems, discussing basic concepts, multimedia networking and synchronization, and an overview of multimedia applications. Part II presents comprehensive coverage of image and video compression techniques and standards, their implementations and applications. Because multimedia data (specifically video and images) require efficient compression techniques in order to be stored and delivered in real-time, video and image compression is a crucial element of an effective multimedia system. In Part III attention is focused on the semantic nature of image and video source material, and how that material may be effectively indexed and retrieved. Topics discussed include static images, full-motion video, and the manner in which compressed representations can facilitate structural analysis. Part III concludes with an extended discussion of a case study. This book serves as an invaluable reference with respect to the most important standards in the field. Video and Image Processing in Multimedia Systems is suitable as a textbook for course use.

Buch. Condizione: Neu. Neuware - The scientists and engineers of today are relentless in their continuing study and analysis of the world about us from the microcosm to the macrocosm. A central purpose of this study is to gain sufficient scientific information and insight to enable the development of both representative and useful models of the superabundance of physical processes that surround us. The engineers need these models and the associated insight in order to build the information processing systems and control systems that comprise these new and emerging technologies. Much of the early modeling work that has been done on these systems has been based on the linear time-invariant system theory and its extensive use of Fourier transform theory for both continuous and discrete systems and signals. However many of the signals arising in nature and real systems are neither stationary nor linear but tend to be concentrated in both time and frequency. Hence a new methodology is needed to take these factors properly into account.

Buch. Condizione: Neu. Neuware - Soldering Handbook for Printed Circuits and Surface Mounting, Second Edition, covers every aspect of this packaging technology, and contains the latest information on design, presolder operations, materials, equipment, surface mount technology, cleaning, quality and inspection, touch-up and repair, process economy, line management, and more.

Buch. Condizione: Neu. This item is printed on demand - it takes 3-4 days longer - Neuware -Stochastic processes are found in probabilistic systems that evolve with time. Discrete stochastic processes change by only integer time steps (for some time scale), or are characterized by discrete occurrences at arbitrary times. Discrete Stochastic Processes helps the reader develop the understanding and intuition necessary to apply stochastic process theory in engineering, science and operations research. The book approaches the subject via many simple examples which build insight into the structure of stochastic processes and the general effect of these phenomena in real systems. The book presents mathematical ideas without recourse to measure theory, using only minimal mathematical analysis. In the proofs and explanations, clarity is favored over formal rigor, and simplicity over generality. Numerous examples are given to show how results fail to hold when all the conditions are not satisfied. Audience: An excellent textbook for a graduate level course in engineering and operations research. Also an invaluable reference for all those requiring a deeper understanding of the subject. 290 pp. Englisch.

Buch. Condizione: Neu. This item is printed on demand - it takes 3-4 days longer - Neuware -Initial public offerings (IPOs) play a crucial role in allocating resources in market economies. Because of the enormous importance of IPOs, an understanding of how IPOs work is fundamental to an understanding of financial markets generally. Of particular interest is the puzzling existence of high initial returns to equity IPOs in the United States and other free-market economies. Audience: Designed for use by anyone wishing to perform further academic research in the area of IPOs and by those practitioners interested in IPOs as investment vehicles. 136 pp. Englisch.

Buch. Condizione: Neu. This item is printed on demand - it takes 3-4 days longer - Neuware -Restructuring Schools presents conceptual and empirical models of school organization for promoting students' achievement. Papers by nationally recognized educational sociologists examine four dimensions of the educational process-school organization and governance, organization of students for instruction, classroom processes, and school-to-work transitions-and suggest methods to increase the effectiveness of each. The volume also explores the innovative concept of output-driven education which redirects attention to student achievement as an outcome variable. 284 pp. Englisch.

Buch. Condizione: Neu. This item is printed on demand - it takes 3-4 days longer - Neuware -Two complete new chapters have been introduced. The first one, Chapter 16, amplifies the many rich interactions between Geographie Information Systems (GIS) and the Navstar CPS. The words and pietures in this new chapter foeus on the powerful eleetronie mapmaking techniques that rely on Navstar navigation together with the many benefits stemming from the full-eolored 'layered' maps now being produeed. Chapter 17, which is also new, deals with Intelligent Vehicle Highway Systems (lVHS). Navstar navigation techniques form the hidden backbone of most of the new electronic teehnologies that are helping to make America's traffic f10w more smoothly. Chapter 17 c10ses with narrative descriptions of three interesting IVHS projects: emergency tow-truck dispatching, optimum ambulance-routing, and the in-car traffie reports now being beamed into family cars cruising along Ameriea's major traffic arteries. Many helpful individuals contributed toward the successful completion of Under standing the Navstar. My lovely wife, Cyndy, was unquestionably the most beneficial contributor. Her affectionate comments and her broad-ranging support were greatly appreciated. So was her diligent and uncomplaining work in word-process ing the many drafts of the final manuseript. The artists, Lloyd and lInka Wing and Anthony and Dianne Vega, were also enormously helpful in providing quality figures and tables on schedule. They have become true masters of the Macintosh computer with its many beils and whistles. Preparing a book for publication is a time-consuming, invigorating task. I hope you enjoy reading it as much as I enjoyed putting it together for your use. 356 pp. Englisch.

Buch. Condizione: Neu. This item is printed on demand - Print on Demand Titel. Neuware -Initial public offerings (IPOs) play a crucial role in allocating resources in market economies. Because of the enormous importance of IPOs, an understanding of how IPOs work is fundamental to an understanding of financial markets generally. Of particular interest is the puzzling existence of high initial returns to equity IPOs in the United States and other free-market economies.Audience: Designed for use by anyone wishing to perform further academic research in the area of IPOs and by those practitioners interested in IPOs as investment vehicles.Springer Verlag GmbH, Tiergartenstr. 17, 69121 Heidelberg 136 pp. Englisch.

Taschenbuch. Condizione: Neu. This item is printed on demand - Print on Demand Titel. Neuware -INTRATHECAL DRUG THERAPY FOR SPASTICITY AND PAIN is a practical manual for nurses and physician assistants who use Intrathecal Drug Infusion for treating patients suffering from spasticity and chronic pain. This book supplies users of this new technology with the information they need to utilize it effectively, including pump mechanics and the pharmacology of drug delivery. No other book of its kind exists, and its users at the over 100 facilities that use implanted drug delivery have relied solely on the pump manufacturer's manuals. The authors are from a leading center for research and applied use of these pumps and, working with Dr. Richard Penn, have spent years developing the skills necessary to utilize this system efficiently. Dr. Penn, who writes the Foreword, has personally implanted over 3000 pumps.Springer Verlag GmbH, Tiergartenstr. 17, 69121 Heidelberg 228 pp. Englisch.

Taschenbuch. Condizione: Neu. This item is printed on demand - Print on Demand Titel. Neuware -Written by members of the Fortran 90 ISO and ANSI committees, this book is the source of the most important information about the powerful Fortran 90 programming language. It is organized so that it may be read beginning to end, but also so that particular topics may be studied directly. All of the important new features of Fortran 90 are covered with examples and case studies are used to illustrate the practical use of features. There are also simple problems designed to enable the reader to exercise their knowledge of the topics learned. Amongst the features of this book are: - free source form, new do and case constructs, recursion, modules, data structures, array processing, internal procedures, optional and keyword arguments, and nonadvancing input/output; - extensive examples of Fortran 90 programs; - case studies that illustrate the practical use of Fortran 90 features; - style notes; - extensive discussion of input/output facilities; - the complete syntax of Fortran 90. 460 pp. Englisch.

Buch. Condizione: Neu. This item is printed on demand - Print on Demand Titel. Neuware -Restructuring Schools presents conceptual and empirical models of school organization for promoting students' achievement. Papers by nationally recognized educational sociologists examine four dimensions of the educational process-school organization and governance, organization of students for instruction, classroom processes, and school-to-work transitions-and suggest methods to increase the effectiveness of each. The volume also explores the innovative concept of output-driven education which redirects attention to student achievement as an outcome variable.Springer-Verlag GmbH, Tiergartenstr. 17, 69121 Heidelberg 284 pp. Englisch.

Buch. Condizione: Neu. This item is printed on demand - Print on Demand Titel. Neuware -Two complete new chapters have been introduced. The first one, Chapter 16, amplifies the many rich interactions between Geographie Information Systems (GIS) and the Navstar CPS. The words and pietures in this new chapter foeus on the powerful eleetronie mapmaking techniques that rely on Navstar navigation together with the many benefits stemming from the full-eolored 'layered' maps now being produeed. Chapter 17, which is also new, deals with Intelligent Vehicle Highway Systems (lVHS). Navstar navigation techniques form the hidden backbone of most of the new electronic teehnologies that are helping to make America's traffic f10w more smoothly. Chapter 17 c10ses with narrative descriptions of three interesting IVHS projects: emergency tow-truck dispatching, optimum ambulance-routing, and the in-car traffie reports now being beamed into family cars cruising along Ameriea's major traffic arteries. Many helpful individuals contributed toward the successful completion of Under standing the Navstar. My lovely wife, Cyndy, was unquestionably the most beneficial contributor. Her affectionate comments and her broad-ranging support were greatly appreciated. So was her diligent and uncomplaining work in word-process ing the many drafts of the final manuseript. The artists, Lloyd and lInka Wing and Anthony and Dianne Vega, were also enormously helpful in providing quality figures and tables on schedule. They have become true masters of the Macintosh computer with its many beils and whistles. Preparing a book for publication is a time-consuming, invigorating task. I hope you enjoy reading it as much as I enjoyed putting it together for your use.Springer Verlag GmbH, Tiergartenstr. 17, 69121 Heidelberg 356 pp. Englisch.

Buch. Condizione: Neu. This item is printed on demand - it takes 3-4 days longer - Neuware -Foreign Direct Investment (FDI) is one avenue for offering assistance to developing countries in their efforts to grow. Small countries typically have limited resources to direct toward investment attraction programs, so the ability to segment the market (of Multinational Corporations looking to invest) is a crucial skill. This book develops and employs an investment preference analysis model to give evidence that homogenous groups of investors can be identified. Once these groups are identified, their needs - specific preference requirements for laws, regulations, incentives, and general conditions - can be more efficiently addressed. 226 pp. Englisch.

Taschenbuch. Condizione: Neu. This item is printed on demand - it takes 3-4 days longer - Neuware -Treatment outcome has certainly improved since Stunkard and McLaren-Hume (1959) reviewed the literature and found that less than 25% of obese patients lost 20 pounds or more and less than 5% lost 40 pounds or more. However, one of the few points on which almost all obesity researchers agree is that to date, our results are quite modest and we are generally unsuccessful in promoting effective weight maintenance among obese persons. As the title of a more recent article, 'Improving long-term weight loss: Pushing the limits of treatment,' (Brownell & Jeffrey, 1987, [emphasis added]) suggests, many believe that we have pushed our current treatment paradigms to the limit. It was with this background in mind that we organized the meeting from which these proceedings issue. The purpose of the three day international meeting was to evaluate the current knowledge base and conceptual paradigms of obesity treatment and to suggest directions for future research and clinical practice. Rather than simply for research reporting, the meeting was primarily for research generation. All speakers were established scientists in the field who were asked to summarize our state of knowledge in a given area rather than present the results of their latest research. Great efforts were taken to ensure that panel discussions occupied a central portion of the conference, and that the questions 'What else do we need to know ' and 'How do we find it out ' were consistently addressed. 292 pp. Englisch.

Buch. Condizione: Neu. This item is printed on demand - it takes 3-4 days longer - Neuware -The EPSRC (Engineering and Physical Science Research Committee of the U. K. ) suggested two Workshops (York University, 22-23 September, 1993 and 15-16 April, 1994) for possible development of polarized electron/photon physics as targeted areas of research. The remit of these meetings included identifying research groups and their activities in polarized electron/polarized photon physics, listing relevant existing facilities (particularly electron spin sources and polarimeters), possible joint projects between research groups in the U. K. , recognizing future needs of projects for research of the highest scientific merit and referring to international comparisons of these research activities. Although very diverse but interconnected, the areas of research presented at the Workshops embrace atomic, molecular, surface, and solid state physics. In more detail these areas covered: electron spin correlations and photon polarization correlations in atomic and molecular collisions and photoionization, electron spin effects in scanning tunneling microscopy, surface and interface magnetism from X-ray scattering and polarized Auger electrons (including analysis of domain structures in solids and surfaces), polarized electrons from multiphoton ionization, quasi-atomic effects in solid state physics, dichroism in molecular and surface processes, Faraday rotation and high-field magneto-optics and polarization effects in simultaneous higher order electron-photon excitations. It is obvious from the spectrum of research fields presented at the Workshops that physicists of primarily two communities, namely those studying electron and photon spin interactions with gaseous atomic and molecular targets and those using condensed matter targets for their studies, interacted very closely witheach other. 372 pp. Englisch.

Buch. Condizione: Neu. This item is printed on demand - it takes 3-4 days longer - Neuware -The term speech processing refers to the scientific discipline concerned with the analysis and processing of speech signals for getting the best benefit in various practical scenarios. These different practical scenarios correspond to a large variety of applications of speech processing research. Examples of some applications include enhancement, coding, synthesis, recognition and speaker recognition. A very rapid growth, particularly during the past ten years, has resulted due to the efforts of many leading scientists. The ideal aim is to develop algorithms for a certain task that maximize performance, are computationally feasible and are robust to a wide class of conditions. The purpose of this book is to provide a cohesive collection of articles that describe recent advances in various branches of speech processing. The main focus is in describing specific research directions through a detailed analysis and review of both the theoretical and practical settings. The intended audience includes graduate students who are embarking on speech research as well as the experienced researcher already working in the field. For graduate students taking a course, this book serves as a supplement to the course material. As the student focuses on a particular topic, the corresponding set of articles in this book will serve as an initiation through exposure to research issues and by providing an extensive reference list to commence a literature survey. Expe rienced researchers can utilize this book as a reference guide and can expand their horizons in this rather broad area. 492 pp. Englisch.

Buch. Condizione: Neu. This item is printed on demand - it takes 3-4 days longer - Neuware -In this monograph, the authors offer a comprehensive examination of the latest research on Laser Chemical Vapor Deposition (LCVD). Chapters explore the physics of LCVD as well as the principles of a wide range of related phenomena-including laser-matter interactions, heat transfer, fluid flow, chemical kinetics, and adsorption. With this reference, researchers will discover how to apply these principles to developing theories about various types of LCVD processes; gain greater insight into the basic mechanisms of LCVD; and obtain the ability to design and control an LCVD system. 408 pp. Englisch.

Buch. Condizione: Neu. This item is printed on demand - it takes 3-4 days longer - Neuware -This treatise is a compendium of refereed papers based on invited talks presented at the American Chemical Society Symposium on Electrorheological (ER) Materials and Fluids. ER fluids were first investigated 50+ years ago. These fluids, which change rheology when placed in an electric field, were recognized, from the beginning, for allowing an extremely efficient interface between electrical control and mechanical devices. Critical problems, however, existed with the initial fluids, which prevented them from serious consideration for large-scale applications. While over time some of the critical problems have been solved and activity in ER technology has increased, commercial success has remained elusive. A recent Department of Energy report concluded that a primary reason for the failure to commercialize this promising technology is due to a lack in understanding the physics and chemistry of how the materials work. The goal of the symposium was to address the issue of understanding how ER materials work and how they can be used. One of the outcomes of the symposium, which we hope is conveyed in this book, is a feeling that if the mechanism of ER is to be fully understood and improved, expertise from diverse fields must be applied to the problem. 388 pp. Englisch.

Buch. Condizione: Neu. This item is printed on demand - it takes 3-4 days longer - Neuware -Low Power Design Methodologies presents the first in-depth coverage of all the layers of the design hierarchy, ranging from the technology, circuit, logic and architectural levels, up to the system layer. The book gives insight into the mechanisms of power dissipation in digital circuits and presents state of the art approaches to power reduction. Finally, it introduces a global view of low power design methodologies and how these are being captured in the latest design automation environments. The individual chapters are written by the leading researchers in the area, drawn from both industry and academia. Extensive references are included at the end of each chapter. Audience: A broad introduction for anyone interested in low power design. Can also be used as a text book for an advanced graduate class. A starting point for any aspiring researcher. 386 pp. Englisch.

Buch. Condizione: Neu. This item is printed on demand - it takes 3-4 days longer - Neuware -Efficient parallel solutions have been found to many problems. Some of them can be obtained automatically from sequential programs, using compilers. However, there is a large class of problems - irregular problems - that lack efficient solutions. IRREGULAR 94 - a workshop and summer school organized in Geneva - addressed the problems associated with the derivation of efficient solutions to irregular problems. This book, which is based on the workshop, draws on the contributions of outstanding scientists to present the state of the art in irregular problems, covering aspects ranging from scientific computing, discrete optimization, and automatic extraction of parallelism. Audience: This first book on parallel algorithms for irregular problems is of interest to advanced graduate students and researchers in parallel computer science. 354 pp. Englisch.