This book presents selected papers from the Fifteenth International Conference on Dependability of Computer Systems (DepCoS-RELCOMEX), which illustrate the diversity of theoretical problems in analysis of performability, reliability and security of contemporary computer systems. Covering also methodologies and practical tools involved in this field, it is a valuable reference resource for scientists, researchers, practitioners and students who are dealing with these subjects. Established in 2006, DepCoS-RELCOMEX is an annual conference series organised by Wrocław University of Science and Technology. It focuses on the dependability and performability of contemporary computer systems – topics that can provide solutions to new challenges in evaluation of their reliability and efficiency. Since they are probably the most complex technical systems ever engineered by humans, the organization of modern computer systems cannot be modelled and analysed solely as structures (however complex and distributed) built only on the basis of technical resources. Instead they should be considered as a unique blend of interacting people (their needs and behaviours), networks (together with mobile properties, iCloud organisation, Internet of Everything) and a large number of users dispersed geographically and producing an unimaginable number of applications. This new, interdisciplinary approach is developing a continually increasing range of methods which apply also the latest findings in artificial intelligence (AI) and computational intelligence (CI).

Dependability analysis is the recent approach to performance evaluation of contemporary systems which tries to cope with new challenges that are brought with their unprecedented complexity, size and diversity. Especially in case of computer systems and networks such evaluation must be based on multidisciplinary approach to theory, technology, and maintenance of systems which operate in real (and very often unfriendly) environments. As opposed to “classic” reliability which focuses mainly on technical aspects of system functioning, dependability studies investigate the systems as multifaceted and sophisticated amalgamations of technical, information and also human resources. This monograph presents selected new developments in such areas of dependability research as mathematical models, evaluation of software, probabilistic assessment, methodologies, tools, and technologies. Intelligent and soft computing methods help to resolve fundamental problems of dependability analysis which are caused by the fact that in contemporary computer systems it is often difficult to find a relation between system elements and system events (the relation between reasons and results) and it is even more difficult to define strict mathematical models with “analytical” relationships between such phenomena.

This book contains papers on selected aspects of dependability analysis in computer systems and networks, which were chosen for discussion during the 16th DepCoS-RELCOMEX conference held in Wrocław, Poland, from June 28 to July 2, 2021. Their collection will be a valuable source material for scientists, researchers, practitioners and students who are dealing with design, analysis and engineering of computer systems and networks and must ensure their dependable operation. Being probably the most complex technical systems ever engineered by man (and also—the most dynamically evolving ones), organization of contemporary computer systems cannot be interpreted only as structures built on the basis of (unreliable) technical resources. Their evaluation must take into account a specific blend of interacting people (their needs and behaviours), networks (together with mobile properties, cloud organization, Internet of Everything, etc.) and a large number of users dispersed geographically and constantly producing an unconceivable number of applications. Ever-growing number of research methods being continuously developed for dependability analyses apply the newest techniques of artificial and computational intelligence. Selection of papers in these proceedings illustrates diversity of multi-disciplinary topics which are considered in present-day dependability explorations.

Theoretical and practical tools to master matrix code design strategy and technique Error correcting and detecting codes are essential to improving system reliability and have popularly been applied to computer systems and communication systems. Coding theory has been studied mainly using the code generator polynomials; hence, the codes are sometimes called polynomial codes. On the other hand, the codes designed by parity check matrices are referred to in this book as matrix codes. This timely book focuses on the design theory for matrix codes and their practical applications for the improvement of system reliability. As the author effectively demonstrates, matrix codes are far more flexible than polynomial codes, as they are capable of expressing various types of code functions. In contrast to other coding theory publications, this one does not burden its readers with unnecessary polynomial algebra, but rather focuses on the essentials needed to understand and take full advantage of matrix code constructions and designs. Readers are presented with a full array of theoretical and practical tools to master the fine points of matrix code design strategy and technique: * Code designs are presented in relation to practical applications, such as high-speed semiconductor memories, mass memories of disks and tapes, logic circuits and systems, data entry systems, and distributed storage systems * New classes of matrix codes, such as error locating codes, spotty byte error control codes, and unequal error control codes, are introduced along with their applications * A new parallel decoding algorithm of the burst error control codes is demonstrated In addition to the treatment of matrix codes, the author provides readers with a general overview of the latest developments and advances in the field of code design. Examples, figures, and exercises are fully provided in each chapter to illustrate concepts and engage the reader in designing actual code and solving real problems. The matrix codes presented with practical parameter settings will be very useful for practicing engineers and researchers. References lead to additional material so readers can explore advanced topics in depth. Engineers, researchers, and designers involved in dependable system design and code design research will find the unique focus and perspective of this practical guide and reference helpful in finding solutions to many key industry problems. It also can serve as a coursebook for graduate and advanced undergraduate students.

A team of recognized experts leads the way to dependable computing systems With computers and networks pervading every aspect of daily life, there is an ever-growing demand for dependability. In this unique resource, researchers and organizations will find the tools needed to identify and engage state-of-the-art approaches used for the specification, design, and assessment of dependable computer systems. The first part of the book addresses models and paradigms of dependable computing, and the second part deals with enabling technologies and applications. Tough issues in creating dependable computing systems are also tackled, including: * Verification techniques * Model-based evaluation * Adjudication and data fusion * Robust communications primitives * Fault tolerance * Middleware * Grid security * Dependability in IBM mainframes * Embedded software * Real-time systems Each chapter of this contributed work has been authored by a recognized expert. This is an excellent textbook for graduate and advanced undergraduate students in electrical engineering, computer engineering, and computer science, as well as a must-have reference that will help engineers, programmers, and technologists develop systems that are secure and reliable.

This book presents a selection of papers about problems which arise in dependability studies of contemporary computer systems and networks. Their collection should be an interesting and inspiring source material for scientists, researchers, engineers, and students who must consider diverse dependability characteristics in design, analysis, or maintenance of computer systems and networks. The papers were presented during the 19th DepCoS-RELCOMEX conference which was the next event in a series organized annually since 2006. Originating as a scientific platform for discussions of reliability aspects in computer engineering, the topical scope of the conference has been constantly expanded to incorporate new dependability challenges brought by recent advances in systems and information technologies. Currently, dependable operation in the context of computer processing means obtaining reliable (true and timely) results in the conditions of processing both quantitative and qualitative data, using precise or fuzzy (often: imitating) models and algorithms. With increasing use of artificial intelligence algorithms and tools, dependability in contemporary information technology and computer engineering calls for methods based on cognitive systems and deep learning techniques. Topical variety of the papers included in these proceedings proves that almost all applications of modern computer systems and networks must take into account the aspect of dependability and also illustrates a wide diversity of multidisciplinary subjects which needs to be considered in this context.