{"product_id":"rfid-systems-isbn-9780470746028","title":"RFID Systems","description":"\u003cb\u003eThis book provides an insight into the 'hot' field of Radio Frequency Identification (RFID) Systems\u003c\/b\u003e  \u003cp\u003e In this book, the authors provide an insight into the field of RFID systems with an emphasis on networking aspects and research challenges related to passive Ultra High Frequency (UHF) RFID systems. The book reviews various algorithms, protocols and design solutions that have been developed within the area, including most recent advances. In addition, authors cover a wide range of recognized problems in RFID industry, striking a balance between theoretical and practical coverage. Limitations of the technology and state-of-the-art solutions are identified and new research opportunities are addressed. Finally, the book is authored by experts and respected researchers in the field and every chapter is peer reviewed.\u003c\/p\u003e  \u003cp\u003e \u003ci\u003eKey Features:\u003c\/i\u003e\u003c\/p\u003e \u003cul\u003e \u003cli\u003eProvides the most comprehensive analysis of networking aspects of RFID systems, including tag identification protocols and reader anti-collision algorithms \u003c\/li\u003e \u003cli\u003eCovers in detail major research problems of passive UHF systems such as improving reading accuracy, reading range and throughput \u003c\/li\u003e \u003cli\u003eAnalyzes other \"hot topics\" including localization of passive RFID tags, energy harvesting, simulator and emulator design, security and privacy \u003c\/li\u003e \u003cli\u003eDiscusses design of tag antennas, tag and reader circuits for passive UHF RFID systems \u003c\/li\u003e \u003cli\u003ePresents EPCGlobal architecture framework, middleware and protocols \u003c\/li\u003e \u003cli\u003eIncludes an accompanying website with PowerPoint slides and solutions to the problems \u003ca href=\"http:\/\/www.site.uottawa.ca\/~mbolic\/RFIDBook\/\"\u003ehttp:\/\/www.site.uottawa.ca\/~mbolic\/RFIDBook\/\u003c\/a\u003e\n\u003c\/li\u003e \u003c\/ul\u003e  \u003cp\u003e This book will be an invaluable guide for researchers and graduate students in electrical engineering and computer science, and researchers and developers in telecommunication industry.\u003c\/p\u003e  About the Editors.  \u003cp\u003ePreface.\u003c\/p\u003e \u003cp\u003eAcknowledgements.\u003c\/p\u003e \u003cp\u003e\u003cb\u003ePart I COMPONENTS OF RFID SYSTEMS AND PERFORMANCE METRICS.\u003c\/b\u003e\u003c\/p\u003e \u003cp\u003e\u003cb\u003e1 Performance of Passive UHF RFID Systems in Practice\u003c\/b\u003e (\u003ci\u003eMiodrag Bolic, Akshay Athalye, and Tzu Hao Li\u003c\/i\u003e).\u003c\/p\u003e \u003cp\u003e1.1 Introduction.\u003c\/p\u003e \u003cp\u003e1.2 Ideal RFID System.\u003c\/p\u003e \u003cp\u003e1.3 Practical RFID Systems.\u003c\/p\u003e \u003cp\u003e1.4 Overview of the Book.\u003c\/p\u003e \u003cp\u003e1.5 Conclusion.\u003c\/p\u003e \u003cp\u003eReferences.\u003c\/p\u003e \u003cp\u003e\u003cb\u003e2 Performance Metrics and Operational Parameters of RFID Systems\u003c\/b\u003e (\u003ci\u003eRaj Bridelall and Abhiman Hande\u003c\/i\u003e).\u003c\/p\u003e \u003cp\u003e2.1 Overview.\u003c\/p\u003e \u003cp\u003e2.2 Key Operational Parameters.\u003c\/p\u003e \u003cp\u003e2.3 Classification of Commercially Available Products.\u003c\/p\u003e \u003cp\u003e2.4 Conclusion.\u003c\/p\u003e \u003cp\u003eProblems.\u003c\/p\u003e \u003cp\u003eReferences.\u003c\/p\u003e \u003cp\u003e\u003cb\u003e3 UHF RFID Antennas\u003c\/b\u003e (\u003ci\u003eDaniel Deavours\u003c\/i\u003e).\u003c\/p\u003e \u003cp\u003e3.1 Dipoles and Relatives.\u003c\/p\u003e \u003cp\u003e3.2 T-Match and Relatives.\u003c\/p\u003e \u003cp\u003e3.3 Putting it Together: Building an RFID Tag.\u003c\/p\u003e \u003cp\u003e3.4 The Environment.\u003c\/p\u003e \u003cp\u003e3.5 Conclusions, Trends, and Challenges.\u003c\/p\u003e \u003cp\u003eReferences.\u003c\/p\u003e \u003cp\u003e\u003cb\u003e4 RFID Tag Chip Design\u003c\/b\u003e (\u003ci\u003eNa Yan, Wenyi Che, Yuqing Yang, and Qiang Li\u003c\/i\u003e).\u003c\/p\u003e \u003cp\u003e4.1 Tag Architecture Systems.\u003c\/p\u003e \u003cp\u003e4.2 Memory in Standard CMOS Processes.\u003c\/p\u003e \u003cp\u003e4.3 Baseband of RFID Tag.\u003c\/p\u003e \u003cp\u003e4.4 RFID Tag Performance Optimization.\u003c\/p\u003e \u003cp\u003e4.5 Conclusion.\u003c\/p\u003e \u003cp\u003eProblems.\u003c\/p\u003e \u003cp\u003eReferences.\u003c\/p\u003e \u003cp\u003e\u003cb\u003e5 Design of Passive Tag RFID Readers\u003c\/b\u003e (\u003ci\u003eScott Chiu\u003c\/i\u003e).\u003c\/p\u003e \u003cp\u003e5.1 Overview.\u003c\/p\u003e \u003cp\u003e5.2 Basics of Passive RFID Operation.\u003c\/p\u003e \u003cp\u003e5.3 Passive RFID Reader Designs.\u003c\/p\u003e \u003cp\u003e5.4 Advanced Topics on RFID Reader Design.\u003c\/p\u003e \u003cp\u003e5.5 Conclusion.\u003c\/p\u003e \u003cp\u003eProblems.\u003c\/p\u003e \u003cp\u003eReferences.\u003c\/p\u003e \u003cp\u003e\u003cb\u003e6 RFID Middleware: Concepts and Architecture\u003c\/b\u003e (\u003ci\u003eNathalie Mitton, Loïc Schmidt, and David Simplot-Ryl\u003c\/i\u003e).\u003c\/p\u003e \u003cp\u003e6.1 Introduction.\u003c\/p\u003e \u003cp\u003e6.2 Overview of an RFID Middleware Architecture.\u003c\/p\u003e \u003cp\u003e6.3 Readers Management.\u003c\/p\u003e \u003cp\u003e6.4 Data Management and Application-Level Events.\u003c\/p\u003e \u003cp\u003e6.5 Store and Share Data.\u003c\/p\u003e \u003cp\u003e6.6 Example.\u003c\/p\u003e \u003cp\u003e6.7 Conclusion.\u003c\/p\u003e \u003cp\u003eProblems.\u003c\/p\u003e \u003cp\u003eReferences.\u003c\/p\u003e \u003cp\u003e\u003cb\u003ePart II TAG IDENTIFICATION PROTOCOLS.\u003c\/b\u003e\u003c\/p\u003e \u003cp\u003e\u003cb\u003e7 Aloha-Based Protocols\u003c\/b\u003e (\u003ci\u003eKwan-Wu Chin and Dheeraj Klair\u003c\/i\u003e).\u003c\/p\u003e \u003cp\u003e7.1 Pure Aloha.\u003c\/p\u003e \u003cp\u003e7.2 Slotted Aloha.\u003c\/p\u003e \u003cp\u003e7.3 Framed Slotted Aloha.\u003c\/p\u003e \u003cp\u003e7.4 Conclusion.\u003c\/p\u003e \u003cp\u003eProblems.\u003c\/p\u003e \u003cp\u003eReferences.\u003c\/p\u003e \u003cp\u003e\u003cb\u003e8 Tree-Based Anti-Collision Protocols for RFID Tags\u003c\/b\u003e (\u003ci\u003ePetar Popovski\u003c\/i\u003e).\u003c\/p\u003e \u003cp\u003e8.1 Introduction.\u003c\/p\u003e \u003cp\u003e8.2 Principles of Tree-Based Anti-Collision Protocols.\u003c\/p\u003e \u003cp\u003e8.3 Tree Protocols in the Existing RFID Specifications.\u003c\/p\u003e \u003cp\u003e8.4 Practical Issues and Transmission Errors.\u003c\/p\u003e \u003cp\u003e8.5 Cooperative Readers and Generalized Arbitration Spaces.\u003c\/p\u003e \u003cp\u003e8.6 Conclusion.\u003c\/p\u003e \u003cp\u003eProblems.\u003c\/p\u003e \u003cp\u003eReferences.\u003c\/p\u003e \u003cp\u003e\u003cb\u003e9 A Comparison of TTF and RTF UHF RFID Protocols\u003c\/b\u003e (\u003ci\u003eAlwyn Hoffman, Johann Holm, and Henri-Jean Marais\u003c\/i\u003e).\u003c\/p\u003e \u003cp\u003e9.1 Introduction.\u003c\/p\u003e \u003cp\u003e9.2 Requirements for RFID Protocols.\u003c\/p\u003e \u003cp\u003e9.3 Different Approaches Used in UHF Protocols.\u003c\/p\u003e \u003cp\u003e9.4 Description of Stochastic TTF Protocols.\u003c\/p\u003e \u003cp\u003e9.5 Comparison between ISO18000-6C and TTF Protocols.\u003c\/p\u003e \u003cp\u003e9.6 Conclusion.\u003c\/p\u003e \u003cp\u003eProblems.\u003c\/p\u003e \u003cp\u003eReferences.\u003c\/p\u003e \u003cp\u003e\u003cb\u003ePart III READER INFRASTRUCTURE NETWORKING.\u003c\/b\u003e\u003c\/p\u003e \u003cp\u003e\u003cb\u003e10 Integrating RFID Readers in Enterprise IT\u003c\/b\u003e (\u003ci\u003eChristian Floerkemeier and Sanjay Sarma\u003c\/i\u003e).\u003c\/p\u003e \u003cp\u003e10.1 Related Work.\u003c\/p\u003e \u003cp\u003e10.2 RFID System Services.\u003c\/p\u003e \u003cp\u003e10.3 Reader Capabilities.\u003c\/p\u003e \u003cp\u003e10.4 RFID System Architecture Taxonomy.\u003c\/p\u003e \u003cp\u003e10.5 EPCglobal Standards.\u003c\/p\u003e \u003cp\u003e10.6 Adoption of High-Level Reader Protocols.\u003c\/p\u003e \u003cp\u003e10.7 Potential Future Standardization Activities.\u003c\/p\u003e \u003cp\u003e10.8 Conclusion.\u003c\/p\u003e \u003cp\u003eProblems.\u003c\/p\u003e \u003cp\u003eReferences.\u003c\/p\u003e \u003cp\u003e\u003cb\u003e11 Reducing Interference in RFID Reader Networks\u003c\/b\u003e (\u003ci\u003eSung Won Kim and Gyanendra Prasad Joshi\u003c\/i\u003e).\u003c\/p\u003e \u003cp\u003e11.1 Introduction.\u003c\/p\u003e \u003cp\u003e11.2 Interference Problem in RFID Reader Networks.\u003c\/p\u003e \u003cp\u003e11.3 Access Mechanism, Regulations, Standards and Algorithms.\u003c\/p\u003e \u003cp\u003e11.4 Comparison.\u003c\/p\u003e \u003cp\u003e11.5 Conclusion.\u003c\/p\u003e \u003cp\u003eProblems.\u003c\/p\u003e \u003cp\u003eReferences.\u003c\/p\u003e \u003cp\u003e\u003cb\u003e12 Optimal Tag Coverage and Tag Report Elimination\u003c\/b\u003e (\u003ci\u003eBogdan Carbunar, Murali Krishna Ramanathan, Mehmet Koyuturk, Suresh Jagannathan, and Ananth Grama\u003c\/i\u003e).\u003c\/p\u003e \u003cp\u003e12.1 Introduction.\u003c\/p\u003e \u003cp\u003e12.2 Overview of RFID Systems.\u003c\/p\u003e \u003cp\u003e12.3 Tree Walking: An Algorithm for Detecting Tags in the Presence of Collisions.\u003c\/p\u003e \u003cp\u003e12.4 Reader Collision Avoidance.\u003c\/p\u003e \u003cp\u003e12.5 Coverage Redundancy in RFID Systems: Comparison with Sensor Networks.\u003c\/p\u003e \u003cp\u003e12.6 Network Model.\u003c\/p\u003e \u003cp\u003e12.7 Optimal Tag Coverage and Tag Reporting.\u003c\/p\u003e \u003cp\u003e12.8 Redundant Reader Elimination Algorithms: A Centralized Heuristic.\u003c\/p\u003e \u003cp\u003e12.9 RRE: A Distributed Solution.\u003c\/p\u003e \u003cp\u003e12.10 Adapting to Topological Changes.\u003c\/p\u003e \u003cp\u003e12.11 The Layered Elimination Optimization (LEO).\u003c\/p\u003e \u003cp\u003e12.12 Related Work.\u003c\/p\u003e \u003cp\u003e12.13 Conclusion.\u003c\/p\u003e \u003cp\u003eProblems.\u003c\/p\u003e \u003cp\u003eReferences.\u003c\/p\u003e \u003cp\u003e\u003cb\u003e13 Delay\/Disruption-Tolerant Mobile RFID Networks: Challenges and Opportunities\u003c\/b\u003e (\u003ci\u003eHongyi Wu and Zhipeng Yang\u003c\/i\u003e).\u003c\/p\u003e \u003cp\u003e13.1 Motivation.\u003c\/p\u003e \u003cp\u003e13.2 Overview of FINDERS.\u003c\/p\u003e \u003cp\u003e13.3 General Feasibility Study.\u003c\/p\u003e \u003cp\u003e13.4 Unique Challenges and Tactics.\u003c\/p\u003e \u003cp\u003e13.5 Related Work.\u003c\/p\u003e \u003cp\u003e13.6 Conclusion.\u003c\/p\u003e \u003cp\u003eProblems.\u003c\/p\u003e \u003cp\u003eReferences.\u003c\/p\u003e \u003cp\u003e\u003cb\u003ePart IV ADDRESSING OTHER CHALLENGES IN RFID SYSTEMS.\u003c\/b\u003e\u003c\/p\u003e \u003cp\u003e\u003cb\u003e14 Improving Read Ranges and Read Rates for Passive RFID Systems\u003c\/b\u003e (\u003ci\u003eZhiguang Fan, Fazhong Shen, Jianhua Shen, and Lixin Ran\u003c\/i\u003e).\u003c\/p\u003e \u003cp\u003e14.1 Introduction.\u003c\/p\u003e \u003cp\u003e14.2 Signal Descriptions and Formulations for Passive Backscatter RFID Systems.\u003c\/p\u003e \u003cp\u003e14.3 Improving the Read Range of a Passive RFID System.\u003c\/p\u003e \u003cp\u003e14.4 Improving the Read Rate of a Passive RFID System.\u003c\/p\u003e \u003cp\u003e14.5 Two Design Examples for RFID System.\u003c\/p\u003e \u003cp\u003e14.6 Conclusion.\u003c\/p\u003e \u003cp\u003eProblems.\u003c\/p\u003e \u003cp\u003eReferences.\u003c\/p\u003e \u003cp\u003e\u003cb\u003e15 Principles and Techniques of RFID Positioning\u003c\/b\u003e (\u003ci\u003eYimin Zhang, Xin Li, and Moeness Amin\u003c\/i\u003e).\u003c\/p\u003e \u003cp\u003e15.1 Introduction.\u003c\/p\u003e \u003cp\u003e15.2 Tag Range Estimation Techniques.\u003c\/p\u003e \u003cp\u003e15.3 DOA Estimation Techniques.\u003c\/p\u003e \u003cp\u003e15.4 RFID Positioning Techniques.\u003c\/p\u003e \u003cp\u003e15.5 Improving Positioning Accuracy.\u003c\/p\u003e \u003cp\u003e15.6 Conclusion.\u003c\/p\u003e \u003cp\u003eProblems.\u003c\/p\u003e \u003cp\u003eReferences.\u003c\/p\u003e \u003cp\u003e\u003cb\u003e16 Towards Secure and Privacy-Enhanced RFID Systems\u003c\/b\u003e (\u003ci\u003eHeiko Knospe and Kerstin Lemke-Rust\u003c\/i\u003e).\u003c\/p\u003e \u003cp\u003e16.1 Introduction.\u003c\/p\u003e \u003cp\u003e16.2 Security and Privacy.\u003c\/p\u003e \u003cp\u003e16.3 Classification of RFID Systems.\u003c\/p\u003e \u003cp\u003e16.4 Attacks on RFID Systems and Appropriate Countermeasures.\u003c\/p\u003e \u003cp\u003e16.5 Lightweight Cryptography for RFID.\u003c\/p\u003e \u003cp\u003e16.6 Conclusion.\u003c\/p\u003e \u003cp\u003eProblems.\u003c\/p\u003e \u003cp\u003eReferences.\u003c\/p\u003e \u003cp\u003e\u003cb\u003e17 Cryptographic Approaches for Improving Security and Privacy Issues of RFID Systems\u003c\/b\u003e (\u003ci\u003eMiyako Ohkubo, Koutarou Suzuki, and Shingo Kinoshita\u003c\/i\u003e).\u003c\/p\u003e \u003cp\u003e17.1 Introduction.\u003c\/p\u003e \u003cp\u003e17.2 Threats against the RFID System.\u003c\/p\u003e \u003cp\u003e17.3 Required Properties.\u003c\/p\u003e \u003cp\u003e17.4 Cryptographic Protocols for Identification with Privacy.\u003c\/p\u003e \u003cp\u003e17.5 Cryptographic Protocols for Authentication without Privacy.\u003c\/p\u003e \u003cp\u003e17.6 Cryptographic Protocols for Privacy and Other Requirements.\u003c\/p\u003e \u003cp\u003e17.7 Implementation.\u003c\/p\u003e \u003cp\u003e17.8 Real Systems and Attacks.\u003c\/p\u003e \u003cp\u003e17.9 Conclusion.\u003c\/p\u003e \u003cp\u003eProblems.\u003c\/p\u003e \u003cp\u003eReferences.\u003c\/p\u003e \u003cp\u003e\u003cb\u003e18 Novel RFID Technologies: Energy Harvesting for Self-Powered Autonomous RFID Systems\u003c\/b\u003e (\u003ci\u003eRaj Bridelall and Abhiman Hande\u003c\/i\u003e).\u003c\/p\u003e \u003cp\u003e18.1 Introduction.\u003c\/p\u003e \u003cp\u003e18.2 Novel Low Power Architectures.\u003c\/p\u003e \u003cp\u003e18.3 Energy Harvesting Optimized for RFID.\u003c\/p\u003e \u003cp\u003e18.4 Future Trends in Energy Harvesting.\u003c\/p\u003e \u003cp\u003e18.5 Conclusion.\u003c\/p\u003e \u003cp\u003eProblems.\u003c\/p\u003e \u003cp\u003eReferences.\u003c\/p\u003e \u003cp\u003e\u003cb\u003e19 Simulators and Emulators for Different Abstraction Layers of UHF RFID Systems\u003c\/b\u003e (\u003ci\u003eChristian Steger, Alex Janek, Reinhold Weiß, Vojtech Derbek, Manfred Jantscher, Josef Preishuber-Pfluegl, and Markus Pistauer\u003c\/i\u003e).\u003c\/p\u003e \u003cp\u003e19.1 Introduction.\u003c\/p\u003e \u003cp\u003e19.2 The Simulation\/Emulation Platforms.\u003c\/p\u003e \u003cp\u003e19.3 UHF RFID Simulation Platform.\u003c\/p\u003e \u003cp\u003e19.4 Real-Time HIL-Verification and Emulation Platform.\u003c\/p\u003e \u003cp\u003e19.5 Higher Class Tag Architecture Based on Energy Harvesting.\u003c\/p\u003e \u003cp\u003e19.6 Conclusion.\u003c\/p\u003e \u003cp\u003eProblems.\u003c\/p\u003e \u003cp\u003eReferences.\u003c\/p\u003e \u003cp\u003eIndex.\u003c\/p\u003e \u003cp\u003e\u003cb\u003eDr Miodrag Bolic,\u003c\/b\u003e University of Ottawa, Canada Miodrag Bolic joined University of Ottawa, Canada in 2004 as an assistant professor. He received his B.Sc. and M.Sc. degrees in electrical engineering from the University of Belgrade in1996 and 2001 and his Ph.D. degree in electrical engineering from SUNY at Stony Brook, USA in 2004. He has over 7 years of industrial experience from the U.S. and Serbia related to physical layer design for Bluetooth and RFID networks as well as embedded and FPGA design. He is a cofounder of a start-up Astraion Inc., NY that develops novel RFID systems.\u003c\/p\u003e \u003cp\u003e\u003cb\u003eProf David Simplot-Ryl\u003c\/b\u003e, Fundamental Computer Science Laboratory of Lille, France David SIMPLOT-RYL received the Graduate Engineer degree in computer science, automation, electronic and electrical engineering, a MSc and PhD degrees in computer science from the University of Lille, France, in 1993 and 1997, respectively. In 1998, he joined the Fundamental Computer Science Laboratory of Lille (LIFL), France, where he is currently professor. He received the Habilitation degree from University of Lille, France, in 2003.\u003c\/p\u003e \u003cp\u003e\u003cb\u003eProf Ivan Stojmenovic\u003c\/b\u003e, University of Ottawa, Canada Ivan Stojmenovic received his Ph.D. degree in mathematics in 1985. He is currently a managing editor of \u003ci\u003eJournal of Multiple-Valued Logic and Soft Computing\u003c\/i\u003e (received Certificate of Appreciation from IEEE Computer Society in 2002 for establishing and maintaining the journal),\u003ci\u003e International Journal of Parallel, Emergent and Distributed Systems (T\u0026amp; F)\u003c\/i\u003e, and \u003ci\u003eAd Hoc \u0026amp; Sensor Wireless Networks, An International Journal (OCP)\u003c\/i\u003e, and editor of several journals.\u003c\/p\u003e  \u003cb\u003eThis book provides an insight into the ‘hot’ field of Radio Frequency Identification (RFID) Systems\u003c\/b\u003e  \u003cp\u003eIn this book, the authors provide an insight into the field of RFID systems with an emphasis on networking aspects and research challenges related to passive Ultra High Frequency (UHF) RFID systems. The book reviews various algorithms, protocols and design solutions that have been developed within the area, including most recent advances. In addition, authors cover a wide range of recognized problems in RFID industry, striking a balance between theoretical and practical coverage. Limitations of the technology and state-of-the-art solutions are identified and new research opportunities are addressed. Finally, the book is authored by experts and respected researchers in the field and every chapter is peer reviewed.\u003c\/p\u003e \u003cp\u003e\u003ci\u003eKey Features:\u003c\/i\u003e\u003c\/p\u003e \u003cul\u003e \u003cli\u003eProvides the most comprehensive analysis of networking aspects of RFID systems, including tag identification protocols and reader anti-collision algorithms\u003c\/li\u003e \u003cli\u003eCovers in detail major research problems of passive UHF systems such as improving reading accuracy, reading range and throughput\u003c\/li\u003e \u003cli\u003eAnalyzes other “hot topics” including localization of passive RFID tags, energy harvesting, simulator and emulator design, security and privacy\u003c\/li\u003e \u003cli\u003eDiscusses design of tag antennas, tag and reader circuits for passive UHF RFID systems\u003c\/li\u003e \u003cli\u003ePresents EPCGlobal architecture framework, middleware and protocols\u003c\/li\u003e \u003cli\u003eIncludes an accompanying website with PowerPoint slides and solutions to the problems (\u003ca href=\"http:\/\/www.site.uottawa.ca\/~mbolic\/RFIDBook\/\" target=\"_blank\"\u003ehttp:\/\/www.site.uottawa.ca\/~mbolic\/RFIDBook\/\u003c\/a\u003e)\u003c\/li\u003e \u003c\/ul\u003e \u003cp\u003eThis book will be an invaluable guide for researchers and graduate students in electrical engineering and computer science, and researchers and developers in telecommunication industry.\u003c\/p\u003e","brand":"Wiley","offers":[{"title":"Default Title","offer_id":47989963489509,"sku":"NP9780470746028","price":179.95,"currency_code":"USD","in_stock":false}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/1842\/7735\/files\/9780470746028.jpg?v=1761786047","url":"https:\/\/k12savings.com\/es\/products\/rfid-systems-isbn-9780470746028","provider":"K12savings","version":"1.0","type":"link"}