Pervasive Computing 研究群 研究能量與研發成果

Members and Research Directions –Sensor networks 曾煜棋、王國禎、黃俊龍 曾煜棋、王國禎、黃俊龍 –WLAN 曾煜棋、王國禎 曾煜棋、王國禎 –Mesh networks 曾煜棋、王國禎 曾煜棋、王國禎 –Mobile peer-to-peer service grid 邵家健、彭文志 邵家健、彭文志 –Ubiquitous sensor/actuator infrastructure 邵家健 邵家健 –Sensor data management and mining 彭文志 、 黃俊龍 彭文志 、 黃俊龍

研發成果

Step 1. Select one hop neighbor nodes closer to the anchor Step 2. Choose the node with the maximum energy level from the selected nodes Energy consumption vs. number of nodes Latency per packet vs. number of nodes. A Cluster-based Energy Efficient Routing Algorithm in Mobile Wireless Sensor Networks

An illustration of dwDVS Effect of WCET/BCET ratio on energy consumption Effect of worst-case utilization on energy consumption A Deferred-Workload-based Dynamic Voltage Scaling Algorithm for Hard Real-Time Systems

Power saving mechanism in PSM-V VoIP over WLANs system architecture A Power Saving MAC Mechanism for VoIP over IEEE e WLANs

Polling scheme comparison Proposed power-efficient polling scheme Scheme Round-robin polling (RRP) scheme [8] On-demand polling (ODP) scheme [4] Power-Efficient Polling (PEP) scheme (Proposed) Characteristics of polling scheme StaticDynamic Complexity of implementation EasyMedium Normalized power consumption HighestMediumLowest Aggregate throughputHigherLower Almost the same as RRP Average end-to-end delayLowestHighestMedium PIFS SIFS PIFS Beacon QoS CF- Poll QoS Null Data ACK TXOP 1 Controlled Access Phase (CAP) ….. QAP QSTA QSTA Beacon.... Contention Period (CP) CAP.... QSTA 1 QSTA 2 QSTA 1 A Power-Efficient MAC Protocol for VoIP Traffic over IEEE e WLANs

Emergency Guiding System by Wireless Sensor Networks Emergency Guiding Scheme Water toward low spot Hazardous regions Distributed adjust weight to find escape path Protocol Stack Monitoring Guidance Interface Tree Reconstruction Support reliable reporting scheme, when emergencies occur Dynamically recover the failure links Low cost and quick convergence

The Deployment and Dispatch Issues of Mobile Wireless Sensor Networks Indoor Sensor Deployment Characteristics - Arbitrary-shaped obstacles in the field - Arbitrary relationships of rc and rs - Fewer sensors required for deployment - Sensor dispatch to reduce deployment cost >> Max-weight max-match problem k-covered Sensor Deployment Characteristics - Deployment for multi- level coverage WSN - Arbitrary relationships of rc and rs - Fewer sensors required for deployment - Distributed sensor dispatch algorithms >> greedy-based & pattern-based schees Multi-type Sensor Dispatch Problem - How to dispatch sensors so that events can be detected on time & total energy consumption can be minimized Event “a” is not detected All events are detected iMouse System Characteristics - Implementation of “mobile” sensor - Provide WSN-based surveillance service - Combine adv. of both WSN and traditional surveillance systems Lego car WebCam Stargate WLAN card Mobile sensor Static sensor

Coverage of a Wireless Sensor Network without Location Information Goal –Determine whether the sensing region of each sensor is sufficiently covered by k other nodes without location information –Provide comparable results to the location-based algorithm

Location Management for Object Tracking in Wireless Sensor Networks Two Location Management Schemes Tree-based location management scheme that consists of (1) The update and query mechanisms (2) The tree construction algorithms

The Beacon Movement Detection Problem in Wireless Sensor Networks for Localization Applications System model: If beacon sensors are moved by accident, the localization error will be increased seriously.

A Noise-Tolerant Indoor Positioning Method by Signal Scrambling Design Guidelines: Propose a tracking scheme to improve accuracy of various localization algorithms Propose a tracking scheme to improve accuracy of various localization algorithms Temporal dependency is used to enlarge real-time sample space Temporal dependency is used to enlarge real-time sample space Spatial dependency is used to select a better location Spatial dependency is used to select a better location System Flow Viterbi-like Location Selection Module

Quick Convergecast in ZigBee/IEEE Tree-Based Wireless Sensor Networks Problem formulation Convergecast is a fundamental operation in wireless sensor networks This paper defines a minimum delay beacon scheduling problem for quick convergecast in ZigBee/IEEE tree-based wireless sensor networks We prove that this problem is NP- complete. Current results Our formulation is compliant with the low- power design of IEEE We propose –Optimal solutions for special cases –Heuristic algorithms for general cases Simulation results show that the proposed algorithms can indeed achieve quick convergecast

Energy Efficient Algorithms for Mobile Sensors Impact of load balancing Sensor dispatching problem in collaborative network This sensor is dead! Remaining sensors bear heavier load Static sensors detect the event Mobile sensors achieve advanced detection

Exploiting Data Coverage for Approximate Query Processing in Wireless Sensor Networks Data Coverage Sensors with correlated readings are clustered together. We pick a representative out from each cluster. The representatives will answer queries; the other sensors only sense the environment and do not respond. Data-Covering Problem Input: set of sensors S, clustering criteria ε Output: set of representatives R Constraint: minimize the size of R while keeping every sensor is clustered.

Filtering Faulty Readings to Improve Data Accuracy in Sensor Networks Stable No cheat x x o o o v.s. Traitor Patriot Unstable cheated x x o Byzantine Problem (trust degree is equal)

Hybrid Program Verification for AFSM Based Sensory-Motor Control Cleaning CrewInteracting AFSM Modules Transform Experiment from continuous domain to discrete domain Use Binary Decision Diagram (BDD) verification technique (for program) to check automatic robot behaviors Based on Rodney Brooks’ Augmented FSM(AFSM) model Described by UNITY specification language Can be verified by BDD-based model checker Verify obstacle avoidance behaviors of roving robot

Resilient Application Layer Multicast Tailored for dynamic Peers with Asymmetric Connectivity Application Layer Multicast (ALM) Minimize and equalize transport latency to all peers Dynamic Peer Behaviors Unpredictable join/leave Asymmetric connectivity Limited upstream bandwidth Application layer Multicast System Multiple Multicast Trees Demand of Helper

Major Projects ZyXEL Inc.: “ e 無線網路下的傳輸品質與快速換手之研究 (QoS and Fast Handover in e WLAN) ”, ZyXEL Inc.: “ e 無線網路下的傳輸品質與快速換手之研究 (QoS and Fast Handover in e WLAN) ”, 工研院 / 學研計畫 : "Communication Protocols for Wireless Access Networks". ( ~ ) 工研院 / 學研計畫 : "Communication Protocols for Wireless Access Networks". ( ~ ) 後卓越計劃 (Program for Promoting Academic Excellence of Universities II), NSC: "Advanced Technologies and Applications for Next Generation Information Networks" 下一世代資訊通訊網路尖端技術與應用 ( ~ ). 後卓越計劃 (Program for Promoting Academic Excellence of Universities II), NSC: "Advanced Technologies and Applications for Next Generation Information Networks" 下一世代資訊通訊網路尖端技術與應用 ( ~ ). – 分項計畫三 : B3G All-IP Wireless Network Technologies, 後三代全 IP 無線網路 技術 – 分項計畫四 : Wireless Ad Hoc and Sensor Networks Technologies, 無線隨意 及感測網路技術 國科會 : “ 藍芽個人無線區域網路上通訊議題之設計實作與分析 ” ( ~ ) 國科會 : “ 藍芽個人無線區域網路上通訊議題之設計實作與分析 ” ( ~ ) 無線感測網路之動態定位技術, National Science Council, August 1, July 31, 2007 無線感測網路之動態定位技術, National Science Council, August 1, July 31, 2007

Prof. Kuochen Wang ( 王國禎教授 ) Areas of research interests Areas of research interests –Wireless networks and mobile Computing Sensor networks, ad-hoc networks, and mesh networks –Power-aware computing and communications –Network reliability and security Publications Publications –Journal papers: 22 –Conference papers: 47 –Book Chapters: 1 B.S., NCTU-Control Eng., 1978 B.S., NCTU-Control Eng., 1978 M.S., Univ. of Arizona-ECE, 1986 M.S., Univ. of Arizona-ECE, 1986 Ph.D., Univ. of Arizona-ECE, 1991 Ph.D., Univ. of Arizona-ECE, 1991 Senior Engineers, Directorate General of Telecommunications, Senior Engineers, Directorate General of Telecommunications, Professor, NCTU-CS, 1999 ~ Professor, NCTU-CS, 1999 ~ Research projects Research projects –NCTU-MediaTek Project: Low power, handover and QoS schemes in heterogeneous wireless networks –NSC Project: Dynamic localization in wireless sensor networks

Prof. Yu-Chee Tseng ( 曾煜棋教授 ) Areas of research interests Areas of research interests –Wireless Network –Communication Protocol –Mobile Computing –Network Security –Wireless Sensor Network –Wireless Mesh Network –Wireless VoIP – Distributed System – Parallel Processing Publications International journal: 91 International journal: 91 International conference: 99 International conference: 99 Book Chapters: 12 Book Chapters: 12 Patents: 2 granted, 5 pending Patents: 2 granted, 5 pending B.S., NTU-CSIE, 1985 B.S., NTU-CSIE, 1985 M.S., NTHU-CSIE, 1987 M.S., NTHU-CSIE, 1987 Ph.D., Ohio State University-CIS, 1994 Ph.D., Ohio State University-CIS, 1994 Professor, NCTU-CS, 2000~ Professor, NCTU-CS, 2000~ Chief Executive Officer, ITRI-NCTU Joint Research Center, 2005~ Chief Executive Officer, ITRI-NCTU Joint Research Center, 2005~ Chairman, NCTU-CS, 2005~ Chairman, NCTU-CS, 2005~ “ Distinguished Alumnus Award ”, 2005, The Ohio State University “ Distinguished Alumnus Award ”, 2005, The Ohio State University Distinguished Research Award (two times) Distinguished Research Award (two times) Distinguished EE Professor Award, The Chinese EE Institute, 2005 Distinguished EE Professor Award, The Chinese EE Institute, 2005

Prof. Wen-Chih Peng ( 彭文志教授 ) B.S., NCTU-CSIE, 1995 B.S., NCTU-CSIE, 1995 M.S., NTHU-CSIE, 1997 M.S., NTHU-CSIE, 1997 Ph.D., NTU-EE, 2001 Ph.D., NTU-EE, 2001 Assistant Professor, NCTU-CS, 2003/8~ Assistant Professor, NCTU-CS, 2003/8~ A member of the IEEE A member of the IEEE Research interests Research interests –Data management and mining in sensor networks –Mobile data management –Data mining/databases Publications Publications –International journal: 8 –International conference:

Prof. Jiun-Long Huang ( 黃俊龍教授 ) Associate Professor, NCTU, 2005 – Associate Professor, NCTU, 2005 – Ph.D., NTU EE, 2003 Ph.D., NTU EE, 2003 M.S., NCTU CSIE, 1999 M.S., NCTU CSIE, 1999 B.S., NCTU CSIE, 1993 B.S., NCTU CSIE, 1993 Research interests Research interests –Mobile data management Dependent data broadcast Dependent data broadcast On-demand data broadcast On-demand data broadcast –Mobile Internet Cache relocation Cache relocation Transcoding proxy Transcoding proxy –Sensor network Publications Publications –Journal papers: 5 –Conference papers:

Prof. John K. Zao ( 邵家健教授 ) Research interests Research interests –Pervasive Sensor-Actuator Systems Autonomous Sensor/Actuator Assembly Model-based Software Specification & Implementation Operational/Functional Component Coordination –Infrastructure-less (P2P) Service Security P2P Security Policy Management P2P Service Security Enforcement Publications Publications Journal Papers : 2 Conference Papers : 7 Internet Draft : 3 Patents : Associate Professor (NCTU), 2004 – Associate Professor (NCTU), 2004 – Ph.D. (Harvard), 1995 Ph.D. (Harvard), 1995 Senior Member, IEEE, 2001 Senior Member, IEEE, 2001 Senior MTS (BBN), 1994 – 2002 Senior MTS (BBN), 1994 – 2002 Principal MTS (BBN), 2002 – 2003 Principal MTS (BBN), 2002 – 2003 Chairman, Security Policy Task Force, DARPA Information Assurance (IA) Program, 1999 – 2000 Chairman, Security Policy Task Force, DARPA Information Assurance (IA) Program, 1999 – 2000 Member, US Army Task Force XXI Tactical Internet Gray- beard Panel, 1996 – 1997 Member, US Army Task Force XXI Tactical Internet Gray- beard Panel, 1996 – 1997 Co-founder, SecurKey Inc. (Canada), 1987 – 1990 Co-founder, SecurKey Inc. (Canada), 1987 – 1990