Enabling Technologies for Wireless E-Business phần 9 pdf

12 Mo bil e Serv i ces Comput i n g 307 1 2.5.1 Scenario A car is parked in a parkin g lot, and th e owner of the car g ets off and walks s omewhere. Before he gets off the car, he t u rns on the alarm system. The owne r carries a cell phone with him, with the phone connected to a wireless alarm system ( WAS) in the car. WAS has sensors that detect whether the car is touched by s omeone. If t h e car i s touc h e d , t h e WAS sen d s an a l ert to t h e owner’s ce ll p h one. Th ereafter , t h e owner sen d s a comman d to t h e WAS t o protect hi s car from b e i ng s to l en. Base d on t h e t hi ef’s r eact i on, di fferent requests / comman d s are sent to t h e W AS and the WAS g ives feedbacks to the thief until the car en g ine is locked f inall y . The WAS works based on not o n ly the owner’s commands, but also context information, such as t h e time, thief’s attem p t, and resources available. T he complete scenario of the WAS is shown in Fig. 12.2 and is explained as f ollows: • A t hi ef touc h es a car. • Th e d etector ( sensor ) of t h e car g ets t h e i nformat i on an d sen d s i t to t h e owner’s ce ll p h one. • T he owner of the car sends an alert invocation command to the WAS. • T he WAS g ives a speech-based alert to the theft, and the volume of the alert is determined b y time: if i t i s da y time, the volume ma y be hi g h er; ot h erw i se, i t i s l ower. • Th e t hi ef cont i nues to tamper t h e car. • Th e d etector g ets t h e i nformat i on, sen d s i t to t h e owner’s ce ll p h one, an d prompts t h at t h e a l ert d oes not ta k e effect. • Th e owner sen d s a p i cture-ta ki n g a l ert comman d to t h e WAS. • T he WAS sends a s p eech-based alert that a p icture will be taken if the theft continues. • T he thief still continues to tam p er the car. • Th e d etector gets t h e i nformat i on, sen d s i t to t h e owner’s ce ll p h one, an d prompts t h at t h e ta ki ng-p i cture a l ert did not ta k e effect. • T he owner sends a picture-takin g command to the WAS. • The WAS invokes the corresponding ser vice and a picture is taken of r r the thief and a speech alert is broadcast; if the disk space is not enou g h to save the p icture, the resource m anager is invoked and virtual memory is added. • Th e t hi ef cont i nues to tamper t h e car. • Th e d etector g ets t h e i nformat i on, sen d s i t to t h e owner’s ce ll p h one, an d prompts t h at t h e p i ctur e - ta ki n g did not ta k e effect. • Th e owner of t h e car sen d s a comman d to t h e WAS to l oc k t h e en gi ne. • T he WAS invokes the service to lock the engine. • Hopefully the thief leaves the car alone. • Opt i ona ll y, t h e WAS can a l so connect to po li ce e i t h er automat i ca ll y or b ase d on t h e owner’s i nstruct i on, at any stage, to report t h e case. 3 08 L J. Z h an g , B. L i , an d Y. Son g Fig . 12.2. S cenar i o of W A S 1 2.5.2 S olut i on T h e arc hi tecture of t h e WAS i s s h own i n F ig . 12.3. T hi s i s an examp l e of a t y p i ca l context-sens i t i ve m obile se r vice. F ou r se r vices ar e ava il a bl e i n t h e WAS , name ly d etector serv i ce, context serv i ce, a l ert serv i ce, an d camera serv i ce. S i nce media data ( p ictures) must be saved, a r e s ource mana g er is desi g ned in case that t here is no adequate disk space. It is also possible that different t y pes of cell p hones are used in the WAS so that a device moderator is desi g ned to suppor t communications between cell p hones and mobile devices. I n this im p lementation, the service is p rovided by a small device that is connected to the car. In general, HTTP p r otocol is not supported by it. So a s pec i f i c commun i cat i on protoco l must b e use d , for examp l e , 802.11. In a ddi t i on , th e ce ll p h one m igh t b e connecte d to t h e Internet by GPRS. T h erefore, a mu l t i mo d a l a d aptat i on i s requ i re d . T h e ce ll p h one must h ave t h e capa bili t y to d etect location and the current time, since thi s inf o rmati o n i s th e co nt e xt tha t su pp orts the mobile service. In s ummary, each mobile device satisfies the basic r e q uirements of mobile services, i.e., multimodal ada p tor, context ada p tor, an d c ontext information collector are included in each of them. 1 2 Mo bil e Serv i ces Comput i n g 309 F i g . 12.3. The architecture of WAS 12.6 Summary W e b serv i ce i s an effect i ve tec h n i que for i mprov i ng b us i ness eff i c i ency b y automat i ng t h e co ll a b orat i o n of h eterogeneous i nformat i on systems. Its potent i a l app li cat i on i n t h e rea l wor ld i s li m i t l ess an d h as b een ent h us i ast i ca lly em b race d by t h e IT i n d ustr y . B y exten di n g i t to t h e w i re l ess an d mo bil e wor ld , muc h more p eop l e can b e connecte d to t h e enormous We b of i nformat i on an d serv i ces, anywhere and anytime. The scope and eff e c tiveness of those i n f ormation services will transcend to a new level, where unlimited new business o pp ortunities exist. Some exam p les are mobile entertainment, mobile enter p rise, and mobile law e nforcement. Part i cu l ar l y, mo bil e We b serv i ce i s an i mportant approac h for rea li z i ng m-commerce, w hi c h i s expecte d to b ecome i ncreas i ng l y popu l ar, f ollowing successful desktop e-commerce. Mobil e service is the next direction of We b serv i ce. Un i que tec h n i ca l c h a ll en g es li e a h ea d , i f mo bil e serv i ces are to b e as successfu l as re g u l ar We b serv i ces. 3 10 L J. Z h an g , B. L i , an d Y. Son g 4 . eXtens ibl e Mar k up Lan g ua g e, h ttp: // www.w3.or g/ XML / 5. W e b Serv i ces Descr i pt i on Lan g ua g e , h ttp: // www.w 3 .or g/ TR / ws dl 6 . Si mp l e O bj ect Access Protoc o l , h ttp: // www.w3.or g/ TR / soap / 7 . U niversal Description, Discovery a n d Integration, htt p ://www.ud d i.org / 8. I EEE Transactions on Mobile Computing, Los Alamitos, CA: IEEE C omputer Soc i ety, 2002 9. S .N. C h uang, A.T.S. C h an, J. Cao, an d R. Ch eung, Act i ve l y d ep l oya bl e mo bil e serv i ces for a d apt i ve we b access, IEEE Internet Comput i ng 8 ( 2 ) , 2004, 26–33 10 . J.F. Hu b er, Mo bil e next- g enerat i on networ k s, IEEE Mu l t i me di a 11 ( 1 ) , 2004, 7 2–83 11 . U n i versa l Resource Locator, h ttp: // www.w3.or g/ A dd ress i n g/ 12 . B luetooth, https://www.bluetooth.or g/ 13 . Wi-Fi, http://www.wi-fi.or g / 14 . 3G, http://www.3 g .co.uk / 1 5. U . Vars h ney, R.J. Vetter, an d R. Ka l a k o t a, Mo bil e commerce: A new front i er , Computer 33 ( 10 ) , 2000, 32–38 16 . J.A. Senn, T h e emergence of m-commerce, Computer 33 ( 12 ) , 2000, 148–150 17. S. Sc h w id ers ki -Grosc h e, an d H. Knospe, Secure mo bil e commerce, E l ectron i cs & Commun i cat i on En gi neer i n g Journa l 14 ( 5 ) , 2002, 228–238 1 8 . B .N. Sc hili t , D.M. H ilb ert , an d J. Trevor , C ontext-aware commun i cat i on , I EEE Wireless Communications [ see also IEEE Personal Communications ] 9( 5 ) , 2002, 46–54 1 9 . J Y. Pan, C P. Tan, W T. Lee , Context-aware service p rotocol, Wireless Commun i cat i ons an d Networ ki ng, 2003, WCNC 2003, 2003 IEEE, vo l ume 3, 16–20 Marc h 2 003 , pp. 20 5 8 – 2063 20. G. N ikl fe ld, M. Puc h er , R. F i nan , an d W. Ec kh art , Mo bil e mu l t i -mo d a l d ata s erv i ces for GPRS p h ones an d b e y on d , mu l t i mo d a l i nterfaces, 2002. P rocee di n g s of Fourt h IEEE Internat i ona l Conference on 14–16 Octo b er 2002, pp . 337–342 2 1 . P.D. Le, B. Srinivasan, V. Malhotra, and N. Mani, Resource and load sharin g i n mobile computin g environments TENCON ’98, 1998. IEEE Re g ion 10 International Conference on Global C onnectivity in Energy, Computer, Communication and Control , vo l ume 1, 17–19 December 1998, pp . 82–85 22. G. Le Grand, J. Ben-Othman, and E. Horlait, Providing quality of service in mo bil e env i ronments w i t h MIR ( mo bil e IP reservat i on protoco l) , networ k s, References 1. W or ld Wid e W e b Co n sort i um, h ttp: // www.w3.or g 2. W 3C , “We b Serv i ces Arc hi tectu r e,” h ttp: // w3 . or g/ TR / ws-arc h/ 3. H y pertext Transfer Protoco l , h ttp: // www.w3.or g/ Protoco l s / 2000 ( ICON 2000 ) . Procee di ngs o f I EEE Internat i ona l Co n f erence on 5–8 Septem b er 2000, pp. 24–29 2 3 . D. Bar k a i , Peer-to-Peer Comput i n g: Tec h no l o gi es for S h ar i n g an d Co ll a b o - rat i n g on t h e Net, H ill s b oro, OR: Inte l Press, 2001 1 2 Mobile Services Computin g 311 24. 8 02.11, http://grouper.ieee.org/groups/802/11/ 2 5 . W ireless A pp lication Protocol, h tt p ://www.w3schools.com/wa p / 26. R.J. Bates , GPRS: General Packet Radio Service , New York: McGraw-Hill , 2002 27. I R. C h en, N.A. P h an, an d I L. Yen, A l gor i t h ms for support i ng di sconnecte d w r i te operat i ons for w i re l ess we b access i n mo bil e c li ent–server env i ronments, IEEE Transactions on Mobile Computin g 1(1), 2002, 46–58 2 8 . M. Ber g er, M. Bouzid, M. Buckland, H. Lee, N. Lhuillier, D. Olpp, J. Picault, and J. Shepherdson, An approach to agent-based service composition and its a pp lication to mobile business p rocesses, IEEE Transactions on Mobile C omputing 2(3), 2003, 197–206 29. E . Ceram i , We b Serv i ces Essent i a l s, Be iji ng, Se b astopo l , CA: O’Re ill y, 2002 30. B. L i , W T. Tsa i , L J. Z h ang, Bu ildi ng e-commerce systems us i ng t h e s emantic a pp lication framework, International Journal of W eb En g ineerin g and Technolo gy 1(3), 2 004, 297–319 13 Location-Aware Services and its Infrastructure Support Y . Chen and D. Liu IBM China Research Laboratory 13.1 Introduction Wi t h a d vances i n w i re l ess Internet a nd mobile computing, location-based services ( LBS ) h ave emerge d as a k ey va l ue-a dd e d serv i ce for te l ecom operators to d e li ve r p ersonalized location-aware content to their subscribers usin g its wireless i nfrastructure. Besides telecom o p erators, more and more service p roviders, suc h as p ublic wireless LAN (PWLAN) p roviders, enterprises, etc. are developin g an d deploying location-aware services for consumers and employees to gain more revenue and productivity. These location-aware services p roviders (LASPs) are f ac i ng b ot h tec h n i ca l a n d soc i a l c h a ll en g e s, suc h as pos i t i on i ng i n var i ous e nv i ronments us i ng di fferent l ocat i ng mec h an i sms, l ocat i on trac ki ng, i nformat i on d e li very mo d e l s, pr i vacy protect i on, an d d eve l op i ng i nnovat i ve LBS app li cat i ons to achieve more business impact and value, amon g others. It has been realized tha t a fl e xi b l e an d r es ili e nt mi dd l ew ar e s h ou l d be built as the enablin g infrastructure to s upport different pla y ers, so that service provider can efficientl y and effectivel y develop and deploy LBS applications, a n d su pp ort innovative location-aware applications quickly. The location-aware infrastructure should address key challenges in location-aware computing a s identified in [1], such as technology- i n d epen d ent l ocat i on sens i ng, en d -to-en d con t ro l of l ocat i on i nformat i on, trac ki ng an d pre di cat i on, an d ot h er researc h c h a ll enges i nvo l v i ng geospat i a l i nformat i on p rocess i ng an d h uman i nteract i on w i t h t h ese i nformat i on. T o a dd ress t h ese c h a ll en g es from a m iddl eware i nfrastructure po i nt of v i ew, a l ocat i on operat i n g reference mo d e l ( LORE ) i s d eve l ope d to capture t h e l ocat i on operat i on semant i cs from a l a y ere d perspect i ve, w h ere r i c h er l ocat i on operat i on s emantic is modeled at a higher layer. The p resented location o p eration semantics addresses many issues, for example, how t o retrieve the location data, how the l ocation data are modeled, how to fuse location from different location sources, h ow to query t h e l ocat i on d ata, h ow to use trac ki ng mec h an i sm to d e li ve r i nte lli gent l ocat i on-aware not i f i cat i on , etc. In a ddi t i on to t h e semant i cs , two ot h er i mportant di mens i ons i n l ocat i on-awar e comput i n g , pr i vac y protect i on an d mana g ement, are a l so covere d by t h e L O R E mo d e l . Base d on t h e LORE mo d e l, di fferent components of t h e l ocat i on-aware i nfrastructure are b u il t to meet t h e requirements of different la y ers and expose APIs to develo p ers to build other components that could plu g into the mode l . In the followin g sections, several ke y com p onents of the LORE infrastructure are i n tr oduced t o s h ow h ow i ssues o f th e 1 3 Location-Aware Services and its Infrastructure Su pp ort 313 l ocation-aware computin g addressed and how the composition of components could facilitate the develo p ment of various location-aware services. The chapter is organized as follows. In Sect. 13.2 the LORE model and the i nfrastructure are presented. Three key com p onents of the infrastructure, location s erver w i t h common a d apter framewor k (C AF ) , mov i ng o bj ect d ata b ase ( MOD ) , an d spat i a l pu bli s h/ su b scr ib e eng i ne are i ntro d uce d i n Sects. 13.3, 13.4, an d 13.5, respect i ve l y. Sect i on 13.6 out li nes t h ere l ate d wor k s , w hil e S ect. 13.8 summar i zes our studies and p resents future directions. 13.2 Location Operating Reference Model and Infrastructure Fi g ure 13.1a illustrates the LORE model pr o p osed to ca p ture the semantics an d management issues required by b u i lding location-aware serv i ces. The LORE model includes four domains: o p eration semantics, management, privacy an d s ecur i ty, an d agent. 1 3.2.1 Operat i on S emant i cs Doma i n T he o p eration semantics dom a in includes layered com p onents that, from botto m to top, are pos i t i on i ng, mo d e li ng, fu si on, query, trac ki ng, an d i nte lli gent not i f i cat i on. T h e l ayere d components exp l i c i t l y d escr ib e t h e d epen d enc i es among components, i .e., t h e upper component uses t h e funct i ona li t i es expose d b y l owe r com p onents to build more advanced functionalities. The overall functionalities p rovide the ca p abilities f o r location-aware a pp lications r equirin g rich location operatin g semantics. The positioning component addresses the issue of technology-independent t l ocation sensing, i.e., how to get the l o c ation information of target objects via s pecific positioning mechanism s . Technical neutral positioning requires that the p os i t i on i ng component i nterface w i t h h eterogeneous pos i t i on i ng equ i pment an d e xpose a un i form v i rtua l pos i t i on i ng m ec h an i sm for ot h er components. T h e component h as to d ea l w i t h two di fferent mo d es of pos i t i on i ng: server b ase d an d c li ent b ase d . In server- b ase d mo d e, t h e l ocat i on of t h e tar g et o bj ect i s measure d an d ca l cu l ate d on t h e server s id e, for examp l e, t h e GSM networ k s cou ld d eterm i ne t h e su b scr ib er’s pos i t i on by th e ce ll w h ere t h e mo bil e p h one i s b e i n g serve d . I n client-based mode, the device does self- p o s itioning, e.g., a device with GPS can determine its location. The m ajor difference between the two modes is how the p os i t i on i ng component retr i eves t h e l ocat i on i nformat i on. In t h e server- b ase d mo d e, t h e component pu ll s t h e l ocat i on from server b y access i ng t h e l ocat i on i nterface ( e.g., LIF [2] i nterface ) expose d b y t h e server. In t h e c li ent- b ase d mo d e, t h e d ev i ce a l wa y s pus h es t h e l ocat i on to t h e pos i t i on i n g component, b ecause i t i s di ff i cu l t for c li ent to h ave a l ocat i on i nterface. Two pos i t i on i n g mo d es requ i re t h e p os i t i on i n g component to support b ot h pus h an d pu ll mo d e l s. 3 14 Y. Chen and D. Liu Fig. 13.1 . ( a ) Location operating reference model. ( b ) Infrastructure supporting l ocat i on-aware serv i ces T he modeling component describes the semantics of location information. As it t comes from different positioning mechan i sms, the location data show grea t h eterogene i t i es i n syntax, name, type, an d metr i c system. For examp l e, t h e LIF exposes l ocat i on d ata i n X ML format, w hil e GPS exposes t h e l ocat i on d ata i n compact bi nary format. GPS can prov id e ve l oc i ty i nformat i on , w hil e most GS M p os i t i on i n g approac h es cannot prov id e suc h d ata. T h e mo d e li n g component i nte g rates h etero g eneous l ocat i on d ata by p rov idi n g a un i form l ocat i on mo d e l t h a t f ac ili tates t h e d eve l opment of f l ex ibl e serv i ces. T h e l ocat i on mo d e l captures enough information on location, inclu d ing coordinates, time, velocity, error, and other related information. T he fusion component addresses the issue of how to derive accurate location by t fus i ng l ocat i on reports from mu l t i p l e d ev i c es for one target o bj ect. For examp l e, a p erson h as a ce ll p h one, a note b oo k computer w i t h w i re l ess car d , an d a GPS r ece i ver, a ll t h ese d ev i ces can b e pos i t i one d an d t h e i r l ocat i on reports are sent to t h e fus i on component for d eterm i n i n g t h e prec i se l ocat i on. T h e fus i on component d er i ves t h e prec i se l ocat i on b ase d on pre d e f i ne d ru l e set, w hi c h ma y d ef i ne t h e p ossibilities of the location accurac y in a different context. There are lot o f i nterestin g topics in the location fusion al g orithms an d r u l e se t t o be r ese ar c h ed. T h e query component provides spatio-temporal query interfaces from which t app li cat i ons an d en d users cou ld get l ocat io n i nformat i on of i ntereste d o bj ects an d 1 3 Locat i on-Aware S erv i ces an d i ts Infrastructure Support 315 issue l oc ati o n-r e lat ed queries. The quer y could inv o lve not onl y current location i nformation, but also historical and/o r future location inf o r mation. A typical l ocation query is “ P lease re p ort the loca t ion of object X . ” Another more com p lex s patio-temporal query involving historical information is “ Please report the “ ob jects t h at are in zone X at time Y . ” T h e query component uses t h e pos i t i on i ng an d/ or fus i on components to get t h e l ocat i on d ata. For support i ng effect i ve hi stor i ca l an d current l ocat i on i nformat i on retr i eva l , t h e query component emp l oys s patial index to improve the quer y performance. The spatial index could be R-tree and its variation, g rid index, Z-order, a nd so on. Location p redication mechanisms are used b y the quer y component to answ e r the q uestion about th e f u t u r e l oc ati o n of specific objects. The tracking component plays a key role in LBS in the sense that most of LBS t app li cat i ons requ i re trac ki ng l ocat i ons of target o bj ects to get t h e tra j ectory an d p rov id es i nformat i on b ase d on t h e l ocat i on o r trajectory. Typical applications r i nc l u d e f l eet management, tax i di spatc h , an d roa d ass i stance nav i gat i on. Trac ki ng p uts si g nificant performance i mpact on the underl y in g positionin g component b y p ositionin g the location of t h e ob j ects continuousl y o r i n a s p ecified time interval. T h e intelligent notification component brings new user experience by sending t l ocation-de p endent m e s sage, including sales prom o t ion, weather and traffic i nformation, nearby events, and so on. A typical application of the intelligen t notification is “ Please sen d me promotion message while I am in zone X . ” The key t ec h no l ogy b e hi n d t h e i nte lli gent not i f i cat i on i s spat i a l pu bli s h/ su b scr i pt i on s erv i ce w h ere users d ef i ne t h e events t h ey are i ntereste d i n, i n a d vance, b y s pec i fy i ng spat i o-tempora l con d i t i ons , an d t h en t h e not i f i cat i on w ill b e d e li vere d to t he m while t he c on di t i on i s met by ta ki n g t h e users’ l ocat i on i nformat i on i nto cons id erat i on. W h en t h e i nte llig ent not i f i cat i on component i s d ep l o y e d fo r s upport i n g a l ar g e num b e r o f users, t h e spat i a l pu b/ su b s h ou ld a l so prov id e s calable mechanism to ena b le intelligent location-aware services. 1 3.2.2 Management Domain Th e mana g ement d oma i n i nc l u d es a ll necessar y mec h an i sms to support mana gi n g t he components in the operation semantics domain except privac y and securit y i ssues, such as confi g uration mana g ement, polic y mana g ement, monitorin g an d l ogg i ng, component ava il a bili ty, an d so on. 1 3.2.3 Pr i vacy and S ecur i ty Doma i n Privac y and securit y pla y important roles i n buildin g l o c ati o n-a w ar e bus in ess s erv i ces w h ere l ocat i on an d t h e user’s pr i vate i nformat i on s h ou ld b e protecte d f rom a b use. T h e pr i vacy an d secur i ty d oma i n prov id es a framewor k to guarantee th at t h e use of l ocat i on i nformat i on i s un d er contro l i n t h e l ocat i on-aware serv i ces e nv i ronment. In t h e pr i vac y framewor k , a use r c an decide who o r which se r vice is a bl e to g et hi s /h er l ocat i on i nformat i o n , an d furt h ermore , t h e user can d ef i ne 3 16 Y. Chen and D. Liu where, when, and wh y ( for what p ur p ose) the inf o rmati o n cou l d be r e tri eved or used. The security framework protects the location information by leveraging p roven security mechanisms, such as encryption, digital signature, and secure trans p ortation p rotocol. 1 3.2.4 Agent Doma i n W ith advances in mobile computing, mobile devices, such as mobile phone and PDA, get more capabilities in computing, networking, and storage. Taking a d vantage of t h e resources i n suc h d ev i ces cou ld h e l p b u ild more sca l a bl e l ocat i on- aware serv i ces an d i nnovat i ve user exper i ences. T h e agent d oma i n i ntro d uces t h e l ocat i on-aware agent t h at res id es i n t h e mo bil e d ev i ce an d cooperates w i t h servers to comp l ete t h e l ocat i on-aware serv i ces. For examp l e, i n t h e trac ki n g serv i ce, a se l f - p os i t i on i n g c li ent, for re d uc i ng t h e networ k traff i c an d resource consumpt i on on t h e s erver side, could send the location info r mation to server only when the changes of rr the location is larger than a predefined threshold. The agent domain provides the f ramework for building service-specific location-aware agent. 1 3.2.5 In f rastructure S upport i ng LORE Model Based on the LORE model, an infrastructure supportin g location-aware services is p ro p osed as de p icted in Fi g. 13.1b. With the support of the infrastructure, t l ocat i on-aware serv i ces, suc h as ye ll ow pages, emergence serv i ces, an d nav i gat i on s erv i ces , cou ld b e create d an d deployed easily. Three prototypes of the key d components i n t h e LBS m iddl eware of t h e i n f rastructure are im plemented, and all m m t h e components i n t h e LORE op e r at io n se mant ics do ma i n ar e cove r ed. • L ocat i on server prov id es t h e pos i t i on i n g , mo d e li n g , an d fus i on com- p onents i n t h e LORE operat i ons se m ant i c d oma i n. A l so i t supports s imple quer y and trackin g funct i onalities. A CAF is introduced to s upport technolo gy - i ndependent location sensin g , whic h i s de tail ed in Sect. 13.3. The location server su pp orts WAP [3] location API and LIF [ 2] i nterface for retr i ev i ng an d query i n g l ocat i on i nforma ti on. A l so t h e l ocat i on server i nc l u d es a pr i vacy mec h an i sm to protect t h e l ocat i o n i nformat i on from b e i n g use d w i t h out t h e owner’s perm i ss i on. • M OD mana g es t h e l ocat i on d ata co ll ecte d from t h e l ocat i on server an d p rov id es t h e quer y an d trac ki n g components i n t h e LORE operat i ons s emantic domain. Continuous, active monitorin g en g ine for location - b ased services ( CAMEL ) [4] is built a s a MOD protot y pe which s u pp orts q ueries of both historical a n d cu rr e nt l oc ati o n inf o rmati o n . MO D di scusse d i n S ect. 13.4. • Spat i a l pu b/ su b eng i ne s upports t h e i nte lli gen t not i f i cat i on componen t i n LORE operat i ons semant i c d oma i n. It prov id es i nterfaces fo r s u b scr ibi n g l ocat i on-aware messa g e an d d ef i n i n g t h e s y stem w id e o r [...]... pp 111–122, 199 8 O Wolfson, A.P Sistla, S Chamberlain, and Y Yesha Updating and querying database that track mobile units Distributed and Parallel Databases 7(3):257–387, 199 9 O Wolfson, A.P Sistla, B Xu, J Zhou, and S Chamberlain DOMINO: Database fOr MovINg Objects tracking Proceedings of ACM SIGMO International Conference on Management of Data, pp 547–5 49, Philadelphia, PA, June 199 9 A.P Sistla,... Imperial College of Science, Technology and Medicine, University of London, 199 8 T Pfeifer and R Popescu-Zeletin A modular location-aware service and application platform, The Fourth IEEE Symposium on Computers and Communications, ISCC 99 , IEEE Computer Society Press, pp 137–148, m 199 9 A Narayanan Realms and states: A framework for location aware mobile computing, Proceedings of the First International... in place for securing user profile databases to prevent misuse or abuse Wireless Network The necessary network infrastructure for wireless mobile computing in general combines various wireless networks, including cellular, wireless LAN, private and public radio, satellite services, and paging As compared with wired networks, wireless radio communications add new challenges The handsets in the wireless. .. Location-Aware Services and its Infrastructure Support 3 19 employee database for an enterprise location-aware system, or on the user profile repository for mobile operators to deploy LBS applications Privacy Service Indiscriminate use of location information for people can infringe people’s privacy Therefore, fine-grained access control to location information is necessary Privacy service provides the privacy... in locationaware computing IEEE Pervasive Computing, 80– 89, April–June 2003 WAP Location Protocol, http://www.wapforum.org/ Location Inter-operability Forum (LIF), http://www.locationforum.org/ Y Chen, F Rao, X Yu, and D Liu, CAMEL: A Moving Object 13 Location-Aware Services and its Infrastructure Support 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 333 D Kwon, S Lee, and S Lee Indexing the current positions... subscription system Proceedings of u Principles of Distributed Computing (PODC 99 ), Atlanta, GA, pp 53–61, May 199 9 A Carzaniga, D.S Rosenblum, and A.L Wolf Achieving scalability and expressiveness in an Internet-scale event notification service, Nineteenth ACM Symposium on Principles of Distributed Computing (PODC2000), Portland, OR, pp 2 19 227, July 2000 I Podnar, M Hauswirth, and M Jazayeri Mobile push: Delivering... r location information Besides the predefined mandatory and optional names for properties, other properties could be attached to the spatial event to describe domain- or application-specific information Usually this information is intended for the subscription application and is not processed by the pub/sub engine Spatial Subscription Model Spatial subscriptions are used by subscribers for expressing... means of interaction for rich content and on multiple communication media In recent times, there has been a dramatic increase in the use of powerful mobile devices These mobile devices, ranging from pagers to mobile phones, wireless PDAs, and wireless laptops, are changing the way people interact at work, on the road, and at home The sophistication of the mobile devices and wireless technologies has advanced... new ways and accomplish personal and professional tasks using this new class of portable, intelligent, wireless mobile devices These mobile devices give people access to information at any time and any place Although some countries have invested more in wireless technologies than others, diverse technologies and systems are t implemented in different parts of the world The capability and number of... live, mobile computing will, in the very near future, become a m prominent means of accessing information on the Internet Just as the PC browser client market matured from accessing the Internet simply for browsing and gathering information to full-blown e-business and e-commerce, the same is happening for mobile devices 336 S Song 14.2 Mobile Commerce 14.2.1 What is Mobile Commerce? Depending on . environments TENCON 98 , 199 8. IEEE Re g ion 10 International Conference on Global C onnectivity in Energy, Computer, Communication and Control , vo l ume 1, 17– 19 December 199 8, pp . 82–85 22. G commun i cat i on , I EEE Wireless Communications [ see also IEEE Personal Communications ] 9( 5 ) , 2002, 46–54 1 9 . J Y. Pan, C P. Tan, W T. Lee , Context-aware service p rotocol, Wireless Commun i cat i ons. S erv i ce In di scr i m i nate use of l ocat i on i nformat i on for peop l e can i nfr i n g e peop l e’s p r i vac y . T h erefore, f i ne- g ra i ne d access contro l to l ocat i on i nformat i on i s n ecessar y .