Mobile Computing - - University of California

Mobile Computing - - University of California

23 Pages · 1996 · 608 KB · English

1. CS 294-7: Challenges of Mobile. Computing. Professor Randy H. Katz. Computer Science Division. University of California, Berkeley. Berkeley, CA 94720- 

Mobile Computing - - University of California free download

1 CS 294-7: Challenges of Mobile Computing Professor Randy H. Katz Computer Science Division University of California, Berkeley Berkeley, CA 94720-1776 ? 1996 2 Natural Evolution of Computing Single User OSBatchTimesharingNetworkingLANs + WSsMobile Computing Freedom from Collocation More Flexible Resource Usage 3 Research Issues in Mobile Computing ?Wireless Communications ?Quality of connectivity ?Bandwidth limitations ?Mobility ?Location transparency ?Location dependency ?Portability ?Power limitations ?Display, processing, storage limitations 4 Classes of Mobile Devices ?Display Only ?InfoPad model: limited portable processing ?Constrained to operation within prepared infrastructure, like a cordless phone ?Advantages with respect to power consumption, upgrade path, lightweight, impact of lost/broken/stolen device ?Laptop Computer ?Thinkpad model: significant portable processing, operates independently of wireless infrastructure ?Disadvantages: power consumption, expensive, significant loss exposure, typically greater than 5 pounds ?Personal Digital Assistant ?Somewhere between these extremes 5 Wireless Communications ?Harsh communications environment: ?Lower bandwidth/higher latency: good enough for videoconferencing? ?Higher error rates ?More frequent disconnection ?Performance depends on density of nearby users but inherent scalability of cellular/frequency reuse architecture helps ?Connection/Disconnection ?Network failure is common ?Autonomous operation is highly desirable ?Caching is a good idea, e.g., web cache ?Asynchronous/spool-oriented applications, like mail or printing ?Trickle back data when bandwidth is available ?Disconnected file systems: CODA (CMU), Ficus (UCLA) 6 Wireless Communications ?Low Bandwidth ?Orders of magnitude differences between wide-area, in- building wireless ?Variable Bandwidth ?Applications adaptation to changing quality of connectivity ?High bandwidth, low latency: business as usual ?High bandwidth, high latency: aggressive prefetching ?Low bandwidth, high latency: asynchronous operation, use caches to hide latency, predict future references/trickle in, etc. etc. ?Heterogeneous Networks ??Vertical Handoff? among colocated wireless networks 7 Heterogeneous ?Wireless Overlay? NetworksIn-BuildingCampus-Area Packet Relay Metropolitan-Area Regional-Area Remote Clinics Emergency Dispatch Hospital Campus Hospital Operating Room Emergency Room 8 Wireless Communications Bandwidths and Latencies Contrast with 100 mbps Fast Ethernet or 155 mbps ATM Plus these bandwidths are SHARED among colocated users! Immediate future: 20 mbps wireless in-building (European HiperLAN) 64 kbps wide area (European GSM) InfoPad: 200 mbps CDMA radio/2 mbps per user Type of Network Bandwidth Latency Mobility Typ Video Performance Typ Audio Performance In-Building >> 1 Mbps Comm?l RF: 2 Mbps Research IR: 50 Mbps < 10 ms Pedestrian 2-Way ?ractive Full Frame Rate (Comp) High Quality 16-bit Samples 22 Khz Rate Campus-Area Packet Relay Network » 64 Kbps » 100 ms Pedestrian Med. Quality Slow Scan Med. Quality Reduced Rate Wide-Area 19.2 Kbps > 100 ms Vehicular Freeze Frame Asynchronous ?Voice Mail? Regional-Area (LEO/DBS/VSAT) 4.8 kbps?10+ Mbps (asymmetric) > 100 ms Vehicular Stationary Seconds/Frame Freeze Frame Asynchronous ?Voice Mail? 9 Wireless Communications ?Security Concerns ?Authentication is critical ?Normal network point of attachment is a wall

------------- Read More -------------

Download mobile-computing-bnrg-cs-berkeley-edu-university-of-california.pdf

Mobile Computing - - University of California related documents

DEPARTMENT of HEALTH and HUMAN - Centers for Disease Control and

507 Pages · 2008 · 6.61 MB · English

influenza, natural disasters, and terrorism, while remaining focused on the threats to health and local, tribal and territorial health network.

Morgan State University

49 Pages · 2013 · 503 KB ·

state and the special needs of Baltimore City Executive Assistant to the President, and Associate and Assistant Vice Presidents. Persons appointed to academic administrative positions serve at the pleasure of the The immediate supervisor shall record occurrences of sick leave used because of.

A Typology of Victim Characterization in Television Crime Dramas

33 Pages · 2010 · 278 KB · English

her analysis of one season of Law & Order, NYPD Blue, and The Practice. She found that only

List of Developing Nations Afghanistan Albania Algeria Angola

2 Pages · 2011 · 538 KB ·

Algeria. Angola. Antigua and Barbuda. Argentina. Armenia. Azerbaijan Hungary. India. Indonesia. Iran, Islamic Republic of. Iraq. Jamaica. Jordan.

22 NAVAJO NATION COUNCIL | Office of the Speaker

2 Pages · 2013 · 295 KB · English

Law and Order Committee receives update regarding and an additional amount of $1.4 million to ensure operation through operations through the winter season.

Building Permits Granted Development Services Department City of San Antonio

84 Pages · 2012 · 272 KB · English

438 RICHLAND HILLS DR BLDG 10. DL CAMBRIDGE DEV GROUP, INC. (713)961-1336 x. 2251200. NEW 2-STORY MULTI-FAMILY APARTMEN. $947,363.00 2284202. 20x4=80 sq ft at csw, 171 sq ft at approach. $0.00. 3106 PIEDRA DE RIO. PRESIDIO CONST LLC. (210)679-8837 x. 2284203.

Department of History Postgraduate Handbook 2017-18

48 Pages · 2017 · 906 KB · English

Social and cultural change in early modern Ireland; the diffusion of print and the changing experience of . support for their modules ( Social Media. The Department of History has a presence on social Format (e.g., film, video, DVD), that is, the

constraints facing the implementation of the greater new orleans urban water plan

5 Pages · 2015 · 480 KB · English

IMPLEMENTATION OF THE GREATER. NEW ORLEANS URBAN WATER PLAN. Annabel Visschedijk en Frans van de Ven*. On September 6th of last year the Greater New Orleans Urban Water Plan. (UWP) was presented. A comprehensive plan which addresses flooding caused by heavy rainfall and 

Rounding Algorithms for a Geometric Embedding of Minimum Multiway Cut

12 Pages · 2010 · 187 KB ·

between its embedded volume and minimum 3-way cut. and 5 we solve the 3-terminal case, giving matching up- cut of any embedded graph.

Litigation Boutique of the Year

4 Pages · 2009 · 2.28 MB ·

arenas. their clients are banks, accounting firms, airlines, energy companies, tobacco is not a cliché. it's gibbs & bruns's lockstep compensation, bredhoff & kaiser's . dollar litigation arising from the bankruptcy of TOUSA, Inc. The