tseng:1

Sensor Networks:Applications and Services

“The most profound technologies are those that disappear. They weave themselves into the fabric of everyday life until they are indistinguishable from it.”

Marc Weiser, The Computer for the 21st Century.

yctseng: 2

Outline

Sensor Networks applications and services “Where are you?”

location management localization problem

yctseng: 3

Definition

Sensing technology: light, temperature, moisture, objects, ect

Embedded computing: small, light, compact software and hardwar

e Wireless communication:

low/medium-rate antenna wireless ad hoc networking

yctseng: 4

Generic System Architecture( 感測網路系統基本架構 )

yctseng: 5

Sensor Hardware( 感測器硬體設計 )

yctseng: 6

Example 1

Digital Sun 公司所發展的自動灑水系統「 S.Sense Wireless Sensor 」

yctseng: 7

Example 2 展覽會場的保全系統 -- Sensicast ART 在博物館、圖書館、畫廊、藝術品展覽會場，防止有價值的藝術品或展覽品遭到竊盜、不經意的觸摸、任意搬動等情形。

主要有兩個模組： OAS 物件警告系統 (Object Alarm System) ：感測

裝置安裝在藝術品底部或背面，藉由偵測燈光的亮度是否改變、測量是否遭受到振動等因素，來確保展覽品的安全。

EMS 環境管理系統 (Environment Management System) ：安裝在展覽會場的牆角、天花板等，偵測展覽環境的溫度、溼度是否超過安全值，以保護展覽品的品質。

yctseng: 8

Example 3 Senera 的橋樑安全監控系統

(89.8.27) 聯絡高雄與屏東之間的高屏大橋突然斷裂，造成多位民眾受傷

Senera 的感測系統，用於監視橋樑、高架橋、高速公路等道路環境。對於許多老舊的橋樑，橋墩長期受到溪水的沖刷，本感測器能夠放置在橋墩底部、用以感測橋墩結構；亦可放置在橋樑兩側或底部，蒐集橋樑的溫度、溼度、振動幅度、橋墩被侵蝕程度等，期望能減少斷橋所造成生命財產的損失。

yctseng: 9

Example 4 Habitat Monitoring on Great Duck Island

遠端利用 Mote 形成的 sensor network 觀察動物的棲息地環境。

Mote 可以供環境光線、溫度…等變化的 sensor node ，藉由形成的 Wireless Sensor Network 可以遠端觀察環境，並且長時間蒐集環境的變化資料。

yctseng: 10

Example 5

工研院 SCAN project (2003): platform with interface to Berkeley Mote Bluetooth devices to form scatternet CO and other sensors

** Other Information: RFID sponsored by Walmart, UPS, etc.

yctseng: 11

SCAN

yctseng: 12

SCAN

tseng:13

“Where are you?”

location management problem localization problem

yctseng: 14

“Where Are You?”

a question used in our daily life

Essence of the question: mapping the location L of an identity ID L = a physical location, a relative location,

a logical areae.g., 45.7th mile of highway I-95, at the north of

Miami, under the table

ID = a person, an object, a phone number

yctseng: 15

Location Mgt. in Cellular Network

ID = Mobile Station ISDN (MSISDN)

L = location area

yctseng: 16

Location Mgt. in IP Networks

ID = IP address L = subnet

yctseng: 17

Location Mgt. in Ad Hoc Networks

ID = host L = physical location assumption: availability of GPS Example: virtual home region

yctseng: 18

One More Example

Grid’s Location Service (GLS) distributed location servers

yctseng: 19

A Short Summary: the Mapping

yctseng: 20

Future Trend

standardization: OSA/OMA

hybrid location database

tseng:21

Positioning Techniques

yctseng: 22

Measurement of Distance Time of arrival Time difference of

arrival

yctseng: 23

Measuring Distance by RF Signal Strength

Path loss formula

An experiment by IEEE 802.11b

yctseng: 24

Positioning by Trilateration ideal situation real situation

yctseng: 25

Fingerprint Location Matching

final point!!

yctseng: 26

Pattern Matching Approach

<ss1, ss2, ..., ssn>

Phase 2real-time phasePhase 1

off-line phase

(xm, ym, <ss1, ss2, ..., ssn>m)

Database

(x2, y2, <ss1, ss2, ..., ssn>2)

(x1, y1, <ss1, ss2, ..., ssn>1)

PositioningModel

(x,y)

training point

final point!!

yctseng: 27

Conclusions

sensor network applications sensor network + instant messaging location management localization