This book discusses design techniques, layout details and measurements of several key analog building blocks that currently limit the performance of 5G and E-Band transceivers implemented in deep-scaled CMOS. The authors present recent developments in low-noise quadrature VCOs and tunable inductor-less frequency dividers. Moreover, the design of low-loss broadband transformer-based filters that realize inter-stage matching, power division/combining and impedance transformation is discussed in great detail. The design and measurements of a low-noise amplifier, a downconverter and a highly-linear power amplifier that leverage the proposed techniques are shown. All the prototypes were realized in advanced nanometer scaled CMOS technologies without RF thick to metal option.

"Heterogeneous Computing with OpenCL "teaches OpenCL and parallel programming for complex systems that may include a variety of device architectures: multi-core CPUs, GPUs, and fully-integrated Accelerated Processing Units (APUs) such as AMD Fusion technology. Designed to work on multiple platforms and with wide industry support, OpenCL will help you more effectively program for a heterogeneous future.

Written by leaders in the parallel computing and OpenCL communities, this book will give you hands-on OpenCL experience to address a range of fundamental parallel algorithms. The authors explore memory spaces, optimization techniques, graphics interoperability, extensions, and debugging and profiling. Intended to support a parallel programming course, "Heterogeneous Computing with OpenCL" includes detailed examples throughout, plus additional online exercises and other supporting materials.
Explains principles and strategies to learn parallel programming with OpenCL, from understanding the four abstraction models to thoroughly testing and debugging complete applications.Covers image processing, web plugins, particle simulations, video editing, performance optimization, and more.Shows how OpenCL maps to an example target architecture and explains some of the tradeoffs associated with mapping to various architecturesAddresses a range of fundamental programming techniques, with multiple examples and case studies that demonstrate OpenCL extensions for a variety of hardware platforms

A survey of microwave technology tailored for professionals in wireless communications

RF Technologies for Low Power Wireless Communications updates recent developments in wireless communications from a hardware design standpoint and offers specialized coverage of microwave technology with a focus on the low power wireless units required in modern wireless systems. It explores results of recent research that focused on a holistic, integrated approach to the topics of materials, devices, circuits, modulation, and architectures rather than the more traditional approach of research into isolated topical areas.

Twelve chapters deal with various fundamental research aspects of low power wireless electronics written by world-class experts in each field. The first chapter offers an overview of wireless architecture and performance, followed by detailed coverage of:

• Advanced GaAs-based HBT designs
• InP-based devices and circuits
• Si/SiGe HBT technology
• Noise in GaN devices
• Power amplifier architectures and nonlinearities
• Planar-oriented components
• MEMS and micromachined components
• Resonators, filters, and low-noise oscillators
• Antennas
• Transceiver front-end architectures

With a clear focus and expert contributors, RF Technologies for Low Power Wireless Communications will be of interest to a wide range of electrical engineering disciplines working in wireless technologies.

This book summarizes the key scientific outcomes of the Horizon 2020 research project TULIPP: Towards Ubiquitous Low-power Image Processing Platforms. The main focus lies on the development of high-performance, energy-efficient embedded systems for the growing range of increasingly complex image processing applications. The holistic TULIPP approach is described in the book, which addresses hardware platforms, programming tools and embedded operating systems. Several of the results are available as open-source hardware/software for the community. The results are evaluated with several use cases taken from real-world applications in key domains such as Unmanned Aerial Vehicles (UAVs), robotics, space and medicine. Discusses the development of high-performance, energy-efficient embedded systems for the growing range of increasingly complex image processing applications; Covers the hardware architecture of embedded image processing systems, novel methods, tools and libraries for programming those systems as well as embedded operating systems to manage those systems; Demonstrates results with several challenging applications, such as medical systems, robotics, drones and automotive.

As we continue to build faster and fast. er computers, their performance is be coming increasingly dependent on the memory hierarchy. Both the clock speed of the machine and its throughput per clock depend heavily on the memory hierarchy. The time to complet. e a cache acce88 is oft. en the factor that det. er mines the cycle time. The effectiveness of the hierarchy in keeping the average cost of a reference down has a major impact on how close the sustained per formance is to the peak performance. Small changes in the performance of the memory hierarchy cause large changes in overall system performance. The strong growth of ruse machines, whose performance is more tightly coupled to the memory hierarchy, has created increasing demand for high performance memory systems. This trend is likely to accelerate: the improvements in main memory performance will be small compared to the improvements in processor performance. This difference will lead to an increasing gap between prOCe880r cycle time and main memory acce. time. This gap must be closed by improving the memory hierarchy. Computer architects have attacked this gap by designing machines with cache sizes an order of magnitude larger than those appearing five years ago. Microproce880r-based RISe systems now have caches that rival the size of those in mainframes and supercomputers."

The insertion of communication networks in feedback control loops complicates analysis and synthesis of cyber-physical systems (CPSs), and network-induced uncertainties may degrade system control performance. Thus, this book researches networked delay compensation and event-triggered control approaches for a series of CPSs subject to network-induced uncertainties. The authors begin with an introduction to the concepts and challenges of CPSs, followed by an overview of networked control approaches and event-triggered control strategies in CPSs. Then, networked delay compensation and event-triggered control approaches are proposed for CPSs with network communication delay, data dropout, signal quantization, and event-triggered communication. More specifically, networked delay compensation approaches are proposed for linear/nonlinear networked controlled plants with time-varying and random network communication delays and data dropouts. To reduce computational burden and network communication loads in CPSs, event-triggered control, self-triggered control, co-design of event-triggered control and quantized control techniques, and event-triggered disturbance rejection control approaches are also presented. This book is an essential text for researchers and engineers interested in cybersecurity, networked control, and CPSs. It would also prove useful for graduate students in the fields of science, engineering, and computer science.

This book introduces readers to the latest advances in sensing technology for a broad range of non-volatile memories (NVMs). Challenges across the memory technologies are highlighted and their solutions in mature technology are discussed, enabling innovation of sensing technologies for future NVMs. Coverage includes sensing techniques ranging from well-established NVMs such as hard disk, flash, Magnetic RAM (MRAM) to emerging NVMs such as ReRAM, STTRAM, FeRAM and Domain Wall Memory will be covered.

An all-inclusive survey of the fundamentals of parallel and distributed computing. The use of parallel and distributed computing has increased dramatically over the past few years, giving rise to a variety of projects, implementations, and buzzwords surrounding the subject. Although the areas of parallel and distributed computing have traditionally evolved separately, these models have overlapping goals and characteristics. Parallel and Distributed Computing surveys the models and paradigms in this converging area of parallel and distributed computing and considers the diverse approaches within a common text. Covering a comprehensive set of models and paradigms, the material also skims lightly over more specific details and serves as both an introduction and a survey. Novice readers will be able to quickly grasp a balanced overview with the review of central concepts, problems, and ideas, while the more experienced researcher will appreciate the specific comparisons between models, the coherency of the parallel and distributed computing field, and the discussion of less well-known proposals. Other topics covered include:

• Data parallelism
• Shared-memory programming
• Message passing
• Client/server computing
• Code mobility
• Coordination, object-oriented, high-level, and abstract models
• And much more

Parallel and Distributed Computing is a perfect tool for students and can be used as a foundation for parallel and distributed computing courses. Application developers will find this book helpful to get an overview before choosing a particular programming style to study in depth, and researchers and programmers will appreciate the wealth of information concerning the various areas of parallel and distributed computing.

1. An up-to-date reference on Red Hat 8 with comparisons to Red Hat's 7 and 6 when warranted. 2. A combination of how to use and administer Linux and operating systems concepts (making this text unique to Linux textbooks) written in an easy-to-read manner. 3. Improved chapters on computer networks, regular expressions and scripting. Revised and additional examples to support the concepts in these chapters. 4. Comparisons between Red Hat Linux and other Linux distributions when such comparisons will be useful. 5. A set of ancillary material including a complete lab manual, text bank, power point notes, glossary of terms, instructor's manual and supplemental readings. The supplemental readings will allow for a smaller book while still retaining all of the important content. 6. Improved chapter reviews, added end-of-section activities, additional tables, improved figures (where possible) and "did you know" boxes inserted to provide useful facts.

This book offers a comprehensive overview of basic communication and networking technologies. It focuses on emerging technologies, such as Software-Defined Network (SDN)-based ad hoc networks, 5G, Machine Learning, and Deep Learning solutions for communication and networking, Cloud Computing, etc. It also includes discussions on practical and innovative applications, including Network Security, Smart Cities, e-health, and Intelligent Systems. Future Trends in 5G and 6G: Challenges, Architecture, and Applications addresses several key issues in SDN energy-efficient systems, the Internet of Things, Big Data, Cloud Computing and Virtualization, Machine Learning, Deep Learning, Cryptography, and 6G wireless technology and its future. It provides students, researchers, and practicing engineers with an expert guide to the fundamental concepts, challenges, architecture, applications, and state-of-the-art developments in communication and networking.

The agile transformation is an act of transforming an organization's form or nature gradually to one that can embrace and thrive in a flexible, collaborative, self-organizing, and fast-changing environment. It seems like most of the companies starting an agile transformation never reach the goal of agility, but there are those few that truly become agile and reap incredible benefits by utilizing DevOps as well. This book introduces the theory and practice of the "double-flywheels model" of Continuous Delivery 2.0: Discovery Loop, which allows information technology (IT) organizations to help businesses figure out the most efficacious ways to develop. Additionally, it explores applications of the Verification Loop that allows IT organizations to deliver value quickly and safely with high quality. Along the way, the book provides an array of insights and case studies that dive into all the aspects of software delivery, and how to implement Continuous Delivery in the most economical way for long-run business development. Features Organization culture and software architecture Business requirement management Pipeline and tooling Branching and releasing strategy Automation strategy Configuration and artefacts management Deployment and production healthy The case studies at the end of the book-scenarios in which the author was personally involved-are explored in depth and meticulously detailed in order to represent typical agile transition scenarios that will benefit all readers.

IOT: Security and Privacy Paradigm covers the evolution of security and privacy issues in the Internet of Things (IoT). It focuses on bringing all security and privacy related technologies into one source, so that students, researchers, and practitioners can refer to this book for easy understanding of IoT security and privacy issues. This edited book uses Security Engineering and Privacy-by-Design principles to design a secure IoT ecosystem and to implement cyber-security solutions. This book takes the readers on a journey that begins with understanding the security issues in IoT-enabled technologies and how it can be applied in various aspects. It walks readers through engaging with security challenges and builds a safe infrastructure for IoT devices. The book helps readers gain an understand of security architecture through IoT and describes the state of the art of IoT countermeasures. It also differentiates security threats in IoT-enabled infrastructure from traditional ad hoc or infrastructural networks, and provides a comprehensive discussion on the security challenges and solutions in RFID, WSNs, in IoT. This book aims to provide the concepts of related technologies and novel findings of the researchers through its chapter organization. The primary audience includes specialists, researchers, graduate students, designers, experts and engineers who are focused on research and security related issues. Souvik Pal, PhD, has worked as Assistant Professor in Nalanda Institute of Technology, Bhubaneswar, and JIS College of Engineering, Kolkata (NAAC "A" Accredited College). He is the organizing Chair and Plenary Speaker of RICE Conference in Vietnam; and organizing co-convener of ICICIT, Tunisia. He has served in many conferences as chair, keynote speaker, and he also chaired international conference sessions and presented session talks internationally. His research area includes Cloud Computing, Big Data, Wireless Sensor Network (WSN), Internet of Things, and Data Analytics. Vicente Garcia-Diaz, PhD, is an Associate Professor in the Department of Computer Science at the University of Oviedo (Languages and Computer Systems area). He is also the editor of several special issues in prestigious journals such as Scientific Programming and International Journal of Interactive Multimedia and Artificial Intelligence. His research interests include eLearning, machine learning and the use of domain specific languages in different areas. Dac-Nhuong Le, PhD, is Deputy-Head of Faculty of Information Technology, and Vice-Director of Information Technology Apply and Foreign Language Training Center, Haiphong University, Vietnam. His area of research includes: evaluation computing and approximate algorithms, network communication, security and vulnerability, network performance analysis and simulation, cloud computing, IoT and image processing in biomedical. Presently, he is serving on the editorial board of several international journals and has authored nine computer science books published by Springer, Wiley, CRC Press, Lambert Publication, and Scholar Press.

This book serves as a practical guide for practicing engineers who need to design embedded systems for high-speed data acquisition and control systems. A minimum amount of theory is presented, along with a review of analog and digital electronics, followed by detailed explanations of essential topics in hardware design and software development. The discussion of hardware focuses on microcontroller design (ARM microcontrollers and FPGAs), techniques of embedded design, high speed data acquisition (DAQ) and control systems. Coverage of software development includes main programming techniques, culminating in the study of real-time operating systems. All concepts are introduced in a manner to be highly-accessible to practicing engineers and lead to the practical implementation of an embedded board that can be used in various industrial fields as a control system and high speed data acquisition system.

Danny Greefhorst is a principal consultant and owner of ArchiXL, and works for clients in the financial and public sector. Danny acts as an IT architect and IT consultant, and is TOGAF 9 certified. He has extensive experience with the definition and implementation of enterprise architectures, application architectures and technical architectures. In addition, he coaches organizations in setting up and executing their architecture function, and is active as an instructor for several classes on architecture. Before starting ArchiXL he worked as a principal consultant at Yellowtail, as a senior IT architect at IBM Business Consulting Services and as a researcher at the Software Engineering Research Centre. Danny is active in the architecture community and regularly publishes on IT and architecture related topics. He is the chairman of the governing board of Via Nova Architectura, a portal and electronic magazine on enterprise architecture. He is also a member of the governing board of the architecture department of the Dutch Computer Science Association (Ngi).

Erik (H.A.) Proper is a senior research manager at the Public Research Centre -- Henri Tudor in Luxembourg, where he leads Services-oriented Enterprise Engineering programme. He also holds a chair in Information Systems at the Radboud University Nijmegen in the Netherlands. Erik has a mixed industrial and academic background. In the past, Erik worked for companies such as Asymetrix, InfoModeller, Origin, ID Research, Ordina and Capgemini, while interleaving this with his work at research institutions such as the Radboud University of Nijmegen, Queensland University of Technology, the Distributed Systems Technology Centre, and the University of Queensland. His general research drive is the modeling of systems. He applies this drive mainly in the fields of service science, enterprise modeling, enterprise engineering and enterprise architecting. He was co-initiator of the ArchiMate project, and currently also serves on the board of the ArchiMate forum of The Open Group. Erik is also one of the editors in chief of Springer's series on enterprise engineering.

This book addresses the topic of exploiting enterprise-linked data with a particular focus on knowledge construction and accessibility within enterprises. It identifies the gaps between the requirements of enterprise knowledge consumption and "standard" data consuming technologies by analysing real-world use cases, and proposes the enterprise knowledge graph to fill such gaps. It provides concrete guidelines for effectively deploying linked-data graphs within and across business organizations. It is divided into three parts, focusing on the key technologies for constructing, understanding and employing knowledge graphs. Part 1 introduces basic background information and technologies, and presents a simple architecture to elucidate the main phases and tasks required during the lifecycle of knowledge graphs. Part 2 focuses on technical aspects; it starts with state-of-the art knowledge-graph construction approaches, and then discusses exploration and exploitation techniques as well as advanced question-answering topics concerning knowledge graphs. Lastly, Part 3 demonstrates examples of successful knowledge graph applications in the media industry, healthcare and cultural heritage, and offers conclusions and future visions.

A decade ago, the corporate world viewed grid computing as a curiosity. Today, it views it as an opportunity--a chance to reduce costs, improve performance, fund new projects, and take advantage of under-utilized capacity. The engineering behind this transformation has been amply documented. Until now, however, little has been written to prepare managers, executives, and other decision-makers to implement grid computing in a sensible and effective way.
Grid Computing: The Savvy Manager's Guide examines the technology from a rigorous business perspective, equipping you with the practical knowledge you need to assess your options and determine what grid computing approach is right for your enterprise. This book is heavy on real-world experience, distilling from a rich assortment of case studies the best practices currently at work in a variety of industries. Always attentive to grid computing s many competitive advantages, it is also realistic about the challenges of selling the idea to staff and making it a part of your company s culture.
Grid Computing has an Online Companion at www.savvygrid.com with contents, details, community forum, and latest updates for the material.
* Sketches the history of grid computing, showing how it made the leap from academia to business.
* Examines the criteria you'll need to meet to make your network "grid-enabled."
* Explains how a grid-based solution can be made to meet key organizational requirements, including security, scheduling, data storage, and fault-tolerance.
* Surveys the approaches currently available and helps you choose the one that will best meet your needs, both now and in the future.
* Focuses heavily on the competitive advantages you can reap from grid computing, and provides advice on convincing your organization to adopt grid computing and making a successful transition."

Thanks to rapid technological developments in terms of Computational Intelligence, smart tools have been playing active roles in daily life. It is clear that the 21st century has brought about many advantages in using high-level computation and communication solutions to deal with real-world problems; however, more technologies bring more changes to society. In this sense, the concept of smart cities has been a widely discussed topic in terms of society and Artificial Intelligence-oriented research efforts. The rise of smart cities is a transformation of both community and technology use habits, and there are many different research orientations to shape a better future. The objective of this book is to focus on Explainable Artificial Intelligence (XAI) in smart city development. As recently designed, advanced smart systems require intense use of complex computational solutions (i.e., Deep Learning, Big Data, IoT architectures), the mechanisms of these systems become 'black-box' to users. As this means that there is no clear clue about what is going on within these systems, anxieties regarding ensuring trustworthy tools also rise. In recent years, attempts have been made to solve this issue with the additional use of XAI methods to improve transparency levels. This book provides a timely, global reference source about cutting-edge research efforts to ensure the XAI factor in smart city-oriented developments. The book includes both positive and negative outcomes, as well as future insights and the societal and technical aspects of XAI-based smart city research efforts. This book contains nineteen contributions beginning with a presentation of the background of XAI techniques and sustainable smart-city applications. It then continues with chapters discussing XAI for Smart Healthcare, Smart Education, Smart Transportation, Smart Environment, Smart Urbanization and Governance, and Cyber Security for Smart Cities.

Cyberspace is changing the face of crime. For criminals it has become a place for rich collaboration and learning, not just within one country; and a place where new kinds of crimes can be carried out, and a vehicle for committing conventional crimes with unprecedented range, scale, and speed. Law enforcement faces a challenge in keeping up and dealing with this new environment. The news is not all bad - collecting and analyzing data about criminals and their activities can provide new levels of insight into what they are doing and how they are doing it. However, using data analytics requires a change of process and new skills that (so far) many law enforcement organizations have had difficulty leveraging. Cyberspace, Data Analytics, and Policing surveys the changes that cyberspace has brought to criminality and to policing with enough technical content to expose the issues and suggest ways in which law enforcement organizations can adapt. Key Features: Provides a non-technical but robust overview of how cyberspace enables new kinds of crime and changes existing crimes. Describes how criminals exploit the ability to communicate globally to learn, form groups, and acquire cybertools. Describes how law enforcement can use the ability to collect data and apply analytics to better protect society and to discover and prosecute criminals. Provides examples from open-source data of how hot spot and intelligence-led policing can benefit law enforcement. Describes how law enforcement can exploit the ability to communicate globally to collaborate in dealing with trans-national crime.

As technology continues to advance and the interconnection of various devices makes our lives easier, it also puts us at further risk of privacy and security threats. Phones can connect to household devices to help set alarms, turn on or off the lights, and even preheat ovens. The Internet of Things (IoT) is this symbiotic interplay of smart devices that collect data and make intelligent decisions. However, the lack of an intrinsic security measure within IoT makes it especially vulnerable to privacy and security threats. Blockchain and IoT Integration highlights how Blockchain, an encrypted, distributed computer filing system, can be used to help protect IoT against such privacy and security breaches. The merger of IoT and blockchain technology is a step towards creating a verifiable, secure, and permanent method of recording data processed by "smart" machines. The text explores the platforms and applications of blockchain-enabled IoT as well as helps clarify how to strengthen the IoT security found in healthcare systems as well as private homes. Other highlights of the book include: Overview of the blockchain architecture Blockchain to secure IoT data Blockchain to secure drug supply chain and combat counterfeits Blockchain IoT concepts for smart grids, smart cities, and smart homes A biometric-based blockchain enabled payment system IoT for smart healthcare monitoring systems

Reviews IoT software architecture and middleware, data processing and management, security, privacy and reliability, architectures, protocols, technologies, algorithms, and smart objects, sensors, and actuators Explores IoT as it applies to energy, including energy efficiency and management, intelligent energy management, smart energy through blockchain and energy-efficient/aware routing/scheduling challenges and issues Examines IoT as it applies to healthcare including biomedical image and signal analysis, and disease prediction and diagnosis Examines IoT as it applies to smart industry including architecture, blockchain, and Industry 4.0 Discusses different ways to create a better IoT network or IoT platform

Provides a structured look, at the unique characteristic for smart sensor networks to resolving the issues of many real-world applications in a broad range of areas such as Smart Healthcare, Engineering, Scientific Research, Social Media, Industrial Automation and more Offers a systematic look at the unique characteristics of AI based wireless sensor networks through their usage in a broad range of areas Delivers recent trends and core concepts in both analytics and application in smart sensor networks using AI Explores the development and application of AI and evolutionary computing as applied to wireless sensor networks Focuses on stepwise discussion, exhaustive literature review, detailed analysis and discussion, rigorous experimentation result and an application-oriented approach.

Modelling Transitions shows what computational, formal and data-driven approaches can and could mean for sustainability transitions research, presenting the state-of-the-art and exploring what lies beyond. Featuring contributions from many well-known authors, this book presents the various benefits of modelling for transitions research. More than just taking stock, it also critically examines what modelling of transformative change means and could mean for transitions research and for other disciplines that study societal changes. This includes identifying a variety of approaches currently not part of the portfolios of transitions modellers. Far from only singing praise, critical methodological and philosophical introspection are key aspects of this important book. This book speaks to modellers and non-modellers alike who value the development of robust knowledge on transitions to sustainability, including colleagues in congenial fields. Be they students, researchers or practitioners, everyone interested in transitions should find this book relevant as reference, resource and guide.

Most of the business sectors consider the Digital Twin concept as the next big thing in the industry. A current state analysis of their digital counterparts helps in the prediction of the future of physical assets. Organizations obtain better insights on their product performance through the implementation of Digital Twins, and the applications of the technology are frequently in sectors such as manufacturing, automobile, retail, health care, smart cities, industrial IoT, etc. This book explores the latest developments and covers the significant challenges, issues, and advances in Digital Twin Technology. It will be an essential resource for anybody involved in related industries, as well as anybody interested in learning more about this nascent technology. This book includes: The future, present, and past of Digital Twin Technology. Digital twin technologies across the Internet of Drones, which developed various perceptive and autonomous capabilities, towards different control strategies such as object detection, navigation, security, collision avoidance, and backup. These approaches help to deal with the expansive growth of big data solutions. The recent digital twin concept in agriculture, which offers the vertical framing by IoT installation development to enhance the problematic food supply situation. It also allows for significant energy savings practices. It is highly required to overcome those challenges in developing advanced imaging methods of disease detection & prediction to achieve more accuracy in large land areas of crops. The welfare of upcoming archetypes such as digitalization in forensic analysis. The ideas of digital twin have arisen to style the corporeal entity and associated facts reachable software and customers over digital platforms. Wind catchers as earth building: Digital Twins vs. green sustainable architecture.

Mobile devices are ubiquitous; therefore, mobile device forensics is absolutely critical. Whether for civil or criminal investigations, being able to extract evidence from a mobile device is essential. This book covers the technical details of mobile devices and transmissions, as well as forensic methods for extracting evidence. There are books on specific issues like Android forensics or iOS forensics, but there is not currently a book that covers all the topics covered in this book. Furthermore, it is such a critical skill that mobile device forensics is the most common topic the Author is asked to teach to law enforcement. This is a niche that is not being adequately filled with current titles. An In-Depth Guide to Mobile Device Forensics is aimed towards undergraduates and graduate students studying cybersecurity or digital forensics. It covers both technical and legal issues, and includes exercises, tests/quizzes, case studies, and slides to aid comprehension.

Originally published in 1995 Time and Logic examines understanding and application of temporal logic, presented in computational terms. The emphasis in the book is on presenting a broad range of approaches to computational applications. The techniques used will also be applicable in many cases to formalisms beyond temporal logic alone, and it is hoped that adaptation to many different logics of program will be facilitated. Throughout, the authors have kept implementation-orientated solutions in mind. The book begins with an introduction to the basic ideas of temporal logic. Successive chapters examine particular aspects of the temporal theoretical computing domain, relating their applications to familiar areas of research, such as stochastic process theory, automata theory, established proof systems, model checking, relational logic and classical predicate logic. This is an essential addition to the library of all theoretical computer scientists. It is an authoritative work which will meet the needs both of those familiar with the field and newcomers to it.