Microsoft PowerPoint - ch0.ppt

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死托常
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1 Chapter 0: Overview Wireless Network Architecture & Potential Research Directions Yu-Chee Tseng Dept of Computer Science National Chiao-Tung University Ch0:1

2 國立交通大國學立資交訊通工大程學系資曾訊煜工棋程系教授曾煜棋教授 Ch0:2

3 Wireless Network Models With Infrastructure: Without Infrastructure (ad hoc networks): Ch0:3

4 Cellular: Infrared: Ch0:4

5 As relaying link Packet Radio Network Ch0:5

6 無線隨意網路 (Multi-hop Ad Hoc Network) Laptop Laptop A Laptop Laptop C' B D PDA E Laptop LaptopC Laptop PDA PDA PDA Ch0:6

7 感測網路 (Sensor Network) Ch0:7

8 Nokia Rooftop Product Ch0:8

9 The Ricochet Network Overview Modem Internet and Corporate Networks 900 MHz Poletop Radio 2.3 GHz 2.4 GHz Wired Access Point High-speed dedicated wired connections Network Interface Facility Ch0:9

10 Easy Installation Ch0:10

11 Bluetooth Technology bluetooth headset bluetooth dongle bluetooth MP3 watch Ch0:11 bluetooth remote car control

12 Research Directions: Mobile Computing, Communications, and MEMS Technologies Ch0:12

13 Three Directions Together Wireless Communication Technology Portable Computer Technology appearance of light-weight computing devices MEMS Technology 微機電系統 (Micro Electro Mechanical Systems,MEMS), 其定義為一個智慧型微小化的系統, 包含感測處理或致動的功能, 包含兩個或多個電子機械光學化學生物磁學或其他性質整合到一個單一或多晶片上其應用領域極為廣泛, 包括製造業自動化資訊與通訊航太工業交通運輸土木營建環境保護農林漁牧等 Vision: Ubiquitous/ Nomadic Computing, communication, and control computers everywhere; information anywhere anytime control 國立交通大學資訊工程系曾煜棋曾煜棋教授 Ch0:13

學生物磁學或其他性質整合到一個單一或多晶片上其應用領域極為廣泛, 包括製造業自動化資訊與通訊航太工業交通運輸土木營建環境保護農林漁牧等 Vision:

14 Features of Wireless Communication one global bandwidth shared by all users fortunately channels, such as (frequency, time-slot) pairs, can be reused Radio-based low bandwidth high latency radio communication links higher bit error rate (BER) fading short-term multipath fading (Rayleigh effect) due to same signal taking different paths and arriving at the receiver shifted in phase long-term fading (radio shadow) 國立交通大學資訊工程系曾煜棋 topology of the terrain (like mountains) can cause signal dropouts 曾煜棋教授 Ch0:14

multipath fading (Rayleigh effect) due to same signal taking different paths and arriving at the receiver shifted in phase

15 Features of Portable Computers Limited resources: limited energy (battery life) limited CPU speed limited memory limited display Mobile Applications/Services Pico-service: local parking lot availability, layout of a building Micro-service: train and bus station information Macro-service: weather information, news service, stock market information Real-time multimedia applications tele-medicine collaborative working environment 國立交通大學資訊工程系曾煜棋曾煜棋教授 Ch0:15

Micro-service: train and bus station information Macro-service: weather information, news service, stock market

16 Features of MEMS MEMS (Micro Electro Mechanical Systems) are the integration of electrical devices and mechanical structures at the micrometer (10-6 m = m) scale. The essence of MEMS is their ability to perform and enhance tasks, in ways and in the micro world, impossible using conventional technologies. digital propulsion Microthruster optical switch segway Ch0:16

The essence of MEMS is their ability to perform and enhance tasks, in ways and in the micro

17 Research: Hardware Aspects power saving display, LCD low-voltage CPUs Example: AT&T's Hobbit chip: 5,000 times less power consumption in doze mode than active mode radio: an example of IEEE power consumption transmit: 1400 mw receive: 1000 mw idle: 830 mw sleep: 130 mw transmitting 1 bit is equal to executing > 1000 instructions Ch0:17

18 Research: Software Aspects mobile communication protocols WAP wireless TCP Mobile IP MAC protocols Energy-efficient protocol related to the above send/receive/idle/sleep model Mobile Operating Systems: Windows Mobile, Android, etc. Ch0:18

protocol related to the above send/receive/idle/sleep model

19 Research: Application Aspects Compute, communicate, and micro-control Context-aware computing context includes user's location environment (e.g., noise level, communication b/w, communication cost etc.) social situation (e.g., with boss, with co-worker etc.) context-aware applications context-sensitive information access (e.g. where are the bookstores in the vicinity) context-sensitive commands: in active badge system command format: <badge> <location> <event-type> <action> Ex: Coffee Kitchen arriving play -v 50 ~/sound/rooster.au 國立交通大學資訊工程系曾煜棋曾煜棋教授 Ch0:19

) context-aware applications context-sensitive information access (e.g.

2.報考人數暨錄取或及格率按類科分_1試

2.報考人數暨錄取或及格率按類科分_1試 103 年公務人員高等考試三級考試暨普通考試 ( 含公職類科第一試 ) 報考人數暨錄取或及格率按類科分報考人數到考人數類科別需用人數錄取標準 % % % % 錄取或及格人數到考率 (%) 錄取或及格率 (%) % % 總到考率總及格率 119,959