PDF-Ad Hoc and Sensor Networks Roger Wattenhofer Ad Hoc and Sensor Networks Roger Wattenhofer

g shooter detection Goals of clock synchronization Compensate offset between clocks Compensate drift between clocks terms are explained on following slides Time Synchronization Sensing Localization Duty Cycling TDMA Ad Hoc and Sensor Networks Roger W. eeethzch Abstract Clock synchronization is one of the most basic building blocks for many applications in computer science and engineering The purpose of clock synchronization is to provide the constituent parts of a distributed system with a common wait Bi l s gna C lock acquire D lock release E signalAll Hoare monitor semantics Assume thread T1 is waiting on condition Assume thread T2 is in the monitor Assume thread T2 calls x signal T2 ives u monitor T2 blocks gp T1 takes over monitor run Abstract. Ad hoc low-power wireless networks are an exciting research direction in sensing and pervasive computing. .. . Prior security work in this area has focused primarily on denial of communication at the routing or medium access control levels. . Macroprogramming. Systems. Presented by: S. M. . Shahriar. . Nirjon. Timothy W.. . Hnat. and . Kamin. Whitehouse. hnat@cs.virginia.edu, WHITEHOUSE@cs.virginia.edu . Motivation. Synchronization Problems. Rui. . Gu. , . Guoliang. . Jin. , . Linhai. Song, . Linjie. Zhu, Shan Lu. University . of Wisconsin – Madison, USA. Proper Thread Synchronization . is . Hard. Very easy to get things wrong. H. ard-to-find concurrency bugs(Data race, Atomicity Violation, Dead Lock). Clock. . Synchronization. in Wireless Sensor Networks. Philipp Sommer. Roger Wattenhofer. Time Synchronization is a well-studied Problem. Time, Clocks, and the Ordering of Events in a Distributed System. Marc S. . Orr. †. §. , . Shuai . Che. §. , Ayse Yilmazer. §. ,. Bradford . M. . Beckmann. §. , Mark . D. . Hill. †. §. , . David A. . Wood. †. §. †. UW-Madison, . §. AMD . Research. ASPLOS, March 16, 2015. Kaushik. . Majumdar. Indian Statistical Institute. 8th Mile, Mysore Road. Bangalore 560059. https://sites.google.com/site/isicng/. Workshop on “Cognition, Emotion and Computing,” Infosys Limited, Bangalore, 30 April 2013. Tan. 2*. . David Yau. 1,3. 1. Advanced Digital Sciences Center (ADSC), Illinois at Singapore. 2. Nanyang Technological University, Singapore. 3. Singapore University of Technology and Design; . John Levine, P.E.. Levine Lectronics and . L. ectric. Why do we need to synchronize our relays?. Relays at all three locations tripped. All three had different times. Are these events related???. Definitions. Professor Hugh C. Lauer. CS-3013, Operating Systems. (Slides include . copyright materials . Modern . Operating Systems. , 3. rd. ed., by Andrew Tanenbaum and from . Operating System Concepts. , 7. th. Time and Clock Time and Clock Primary standard of time = rotation of earth De facto primary standard = atomic clock (1 atomic second = 9,192,631,770 orbital transitions of Cesium 133 atom. Time and Clock Time and Clock Primary standard of time = rotation of earth De facto primary standard = atomic clock (1 atomic second = 9,192,631,770 orbital transitions of Cesium 133 atom. . . Makoto Muto (Graduate School of Business Administration, . Hitotsubashi. U., Japan). Tamotsu . Onozaki. (Faculty of Economics, . Rissho. U., Japan). Yoshitaka Saiki (Graduate School of Business Administration, .