challenges in location-aware computing cynthia a. patterson, richard r. muntz, and cherri m. pancake...
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Challenges in Location-Aware Computing
Cynthia A. Patterson, Richard R. Muntz, and Cherri M. Pancake
IEEE Pervasive Computing 2003
Outline Location-Aware Computing
Location-sensing infrastructure Adaptive resource management Other research challenges
Conclusion
Independent Technologic
Location-aware computing Context-aware computing- 反應到 real-world context
User identity Physical location Current Condition Time of day,date,season User asleep or awake
Location information and identity 是主要關鍵 Location-aware computing
Mobile computing Location sensing Wireless networking
Hardware for mobile computing
Integrating mobile hardware system and seamlessly bridge user’s desktop
Design issue: battery,size,weight Security Performance and reliability Energy source
seamlessly bridge user’s desktop
Location sensing Global Positioning System (GPS) 是個方法 , 目前大概 $100, 越來越廣泛
GPS 一些問題考量 :
不能使用於室內 , 特別是金屬建築 對於一些應用準確度還是不夠好 使用 coordinate system Weight ,cost,energy consumption
Other location-sensing mechanism 一按即發出訊號的信號器 , 行動徽章…
LAR(location aided routing)
MESH: multi-eye spiral-hopping routing
How to serach location ?
PDA PDA
Tablet PC
Tablet PCNotebook Notebook
Tablet PC PDAPDA
PDA
PDA
802.11 Ad Hoc mode
PDA PDA
PDA
PDA
PDA
Notebook
Notebook
PDA
Tablet PC
Tablet PCTablet PC
Location-Aware Multicast Protocol for Bluetooth
Location-Aware Multicast Protocol for Bluetooth
利用 flooding 達成收集 location information
Location sensing ?
A mechanism for discovering spatial relationships between objects
Variety of MechanismsACTIVEe.g. radar and reflective sonar systems
System emits signal, deduces target location from distortions in signal returns
CO-OPERATIVEORL Active Bat, GALORE Panel, AHLoS, GPS, MIT Cricket, UNC HighBall
Target cooperates with the system
BLINDAcoustic “blind beamforming” (Yao)
System deduces location of target without a priori knowledge of its characteristics
?
PASSIVEMicrosoft RADAR
System deduces location from observation of signals that are “already present”
Definitely no “one size fits all” solution
ACTIVE
System emits signal, deduces target location from distortions in signal returns
TargetSynchronization channelRanging channel
CO-OPERATIVE
Target cooperates with the system
TargetSynchronization channelRanging channel
PASSIVE
System deduces location from observation of signals that are “already present”
TargetSynchronization channelRanging channel
BLIND System deduces location of target without a priori
knowledge of its characteristics
?
TargetSynchronization channelRanging channel
Wireless communications Voice commnication(cell phones) IEEE802.11 WLAN Bluetooth IrDA
Power is important factor for mobile device Other: frequency,bandwidth,range,density of wired
infrastructure Trade-offs 就要看需求來決定了
Bluetooth
Using Bluetooth Technology
無線區域網路技術比較表
無線區域網路技術比較表
無線區域網路技術比較表
Location-sensing Infrastructure
Location-based services GPS and other localization technologies Wireless communication Mobile computing
Location-sensing infrastructure can become commercially viable
Technology-independent location sensing
因素太多 , 於是討論發展 a technology-independent , high-level software application programming interface for location-sensing.
發展 middleware level API 將有助於 long-lived applications, 而且遇到的障礙將刺激發展 new location-sensing technologic.
API 最好是 open, specification, dynamically combining location information from multiple source
Opportunistic data acquisition
Cars,Road maintenance personnel using data-mining and visualization software, GPS,Real-time system,可以防止事故 , 節省能量 , 預防結冰
Challenge Address scalability Mobile sensor source Appropriate information-sharing policy Privacy Not sacrificing functionality( 功能 )
End-to-end control of location information
Cell-based location sensing,loss of privacy Historical location information 可以幫助預測
user’s typical movement 需要發展 end-to-end control of location
information, 也就是需要好的 access control mechanism, 得到正確的資料 , 不正確的丟棄 , 而且利用 location information 加強 Security 機制
Test bed for experimental research
Lack adequate large-scale experimental infrastructure, 可以促進發展 commercialization Standard protocols APIs Platform-independent capability Scalability Different network nodes information conflicting Resource management Static-mobile load balancing
NS2
Adaptive Resource Management
Cyber foraging Guide a mobile user from a bandwidth-
impoverished to a bandwidth-rich enviroment. This technique is cyber foraging.
Temporarily extends a mobile computer’s resources by pointing to remote resources.
Infostation Provide low-cost,low-power access information
services 處理這些事情可以使用 surrogates( 代理人 ) 的方
法 , 對使用者無察覺無狹縫 , 要有選擇代理人的方法
Tracking and predicting location
例如 :eletronic map 結合 tracking and predicting location 選擇最好的路
物體的移動和速度對於 location 資料的正確性將是挑戰 , trade-offs 頻寬浪費和 location 資料正確性
所以開始研究預測路徑 , 典型的 home-office-home, 但是如果不正常的移動 , 就會無法完美預測 , 而且必須發展認證或確認身分的機制
前提還要有其他技術支援 , 如 public transportation, good software 回應 user 的要求
Bluetooth Location Networks
Location Tracking Protocol in Sensor Network
Other Research challenges Geospatial database and data mining
Database integrate geospatial data Query language and algorithmic 分解 data space and time Data mining and Data analysis and evaluation benefit
Human interaction with geospatial information 缺乏綜合 framework 來理解 human interaction with
geospatial information
New location information research Smart dust sensors- 農業 ,…
Wireless Sensor Networks
Sensing
Computation
Networking
New technologies have reduced the cost, size and power of micro-sensors and wireless interfaces
Systems can Embedded into environment Sense phenomena at close range
Systems will revolutionize Environmental monitoring Disaster scenarios Structure Response
Environmental Monitoring
Circulatory Net
Some Networked Sensor Node Developments
LWIM III
UCLA, 1996
Geophone, RFM
radio, PIC, star
network
AWAIRS I
UCLA/RSC 1998
Geophone, DS/SS
Radio, strongARM,
Multi-hop networks
Processor
Sensor Mote
UCB, 2000
RFM radio,
PIC
WINS NG 2.0
Sensoria, 2001
Node development
platform; multi-
sensor, dual radio,
Linux on SH4,
Preprocessor, GPS
Real-World Experiences Ad Hoc Sensor Network
Each audience member is given a voting device, users respond to questions by pressing the buttons.
100 node voting devices in the San Francisco Moscone Convention Center. Routing topology using DSDV protocol.
Gateway node
Conclusion IT Roadmap report
(http://www.cstb/project_geospatial.html)