Research Article Grid-PPPS: A Skyline Method for Efficiently Handling Top-k Queries in Internet of Things

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1 Appl Mtmts, Artl ID 41618, 1 ps ttp://x.o.or/1.1155/214/41618 Rsr Artl Gr-: A Skyln Mto or Ently Hnln Top-k Qurs n Intrnt o Tns Sun-Youn Im, 1 Azz Nsrnov, 2 n Youn-Ho Prk 1 1 Dprtmnt o Multm Sns, Sookmyun Womn s Unvrsty, Conp-ro 47-l 1, Yonsn-u, Soul , Rpul o Kor 2 Sool o Computr Ennrn, Donuk Unvrsty t Gyonu, 123 Don-ro, Gyonu, Gyonuk , Rpul o Kor Corrsponn soul rss to Youn-Ho Prk; yprk@sm..kr Rv 22 Jnury 214; Apt 7 Aprl 214; Puls 8 My 214 Am Etor: Youn-Sk Jon Copyrt 214 Sun-Youn Im t l. Ts s n opn ss rtl strut unr t Crtv Commons Attruton Lns, w prmts unrstrt us, struton, n rprouton n ny mum, prov t ornl work s proprly t. A rp vlopmnt n wrlss ommunton n ro rquny tnoloy s nl t Intrnt o Tns (IoT) to ntr vry spt o our l. Howvr, s mor n mor snsors t onnt to t Intrnt, ty nrt u mounts o t. Tus, wspr ploymnt o IoT rqurs vlopmnt o solutons or nlyzn t potntlly u mounts o t ty nrt. A top-k qury prossn n ppl to ltt ts tsk. T top-k qurs rtrv k tupls wt t lowst or t st sors mon ll o t tupls n t ts. Tr r mny mtos to nswr top-k qurs, wr skyln mtos r nt wn onsrn ll ttrut vlus o tupls. T rprsnttv skyln mtos r sot-ltr-skyln (SFS) lortm, nl-s sp prttonn (ABSP), n pln-prot-prlll-skyln (). Amon tm, mprovs ABSP y prttonn t sp nto numr o sps usn yprpln proton. Howvr, s nx uln tm n -mnsonl tss. In ts ppr, w propos nw skyln mto (ll Gr-) or ntly nln top-k qurs n IoT ppltons. T propos mto rst prorms r-s prttonn on t sp n tn prttons t on n usn yprpln proton. Exprmntl rsults sow tt our mto mprovs t nx uln tm ompr to t xstn stt-o-t-rt mtos. 1. Introuton A rp vlopmnt n wrlss ommunton n ro rquny tnoloy s nl t Intrnt o Tns (IoT) to ntr vry spt o our l. T IoT s prt o t ntrnt o t utur n wll omprs llons o ntllnt ommuntn tns w wll v snsn, tutn, n t prossn plts [1]. For xmpl, t tns n IoT n smrt vs n om or om pplns su s rrrtor, wsn mn, n r ontonr, w v ontrolll vs. Rsturnts, otls, n ountrs n lso onsr s t tns n IoT, sn ty r onnt n ommunt wt otr. Howvr, s mor n mor snsors t onnt to t Intrnt, ty nrt normous mounts o t. Tus, wspr ploymnt o IoT rqurs vlopmnt o solutons or nlyzn t potntlly u mounts o t ty nrt [2 4]. A top-k quryprossnnppltoltt ts tsk. T top-k qury ns k tupls wt t lowst or t st sors mon ll o t nput tupls. Wn ts s lr, t my tk lon omputn tm to n omplt nswr to qury. Most usrs, owvr, r ntrst n lookn t ust w top rsults, w r rnk y smll st o ttrut vlus, n ty wnt to s t rsults mmtlytrtyssutqury[5]. W n pply ts noton to n t top-k rsults n u mounts o t n IoT ppltons. Exmpl 1 prsnts t snro to n t top-k rsults n IoT ppltons. Exmpl 1. Consr usr Jon, wo wnts to v nnr n n Itln rsturnt. H ns t ollown rtr or t sr: t stn o rsturnt rom s om soul lss tn 8 mtrs n pr soul lss tn

2 2 Appl Mtmts 1 A 8 B I J 1 A 8 B I J Pr 6 C H K Pr 6 C H K 4 D G 4 D G 2 E F 2 E F Dstn Dstn () Dt o Exmpl 1 () Skyln o Exmpl 1 Fur 1: Grpl rprsntton o t n skyln. Tl 1: T lst o rsturnts n Exmpl 1. Numr Nm Dstn (1 m) Pr ($1) Sor A Mo No sor B Lttl Pst C L Tvol D lv Grn E Alto F Mlros No sor G Morton Hous No sor H Appl s I Boulvr No sor J IHP No sor K Sow Brook US Dollrs. In orr to n rsturnt tt st suts s ntrst, Jon mks sorn unton s (t) =.4 stn +.6 pr, wr t s t tupl o ts. Hr, w n tnk o t rsturnt s tn n IoT. All rsturnts ronnttotintrnt,wormstntworko IoT. Fnn t top-k rsults mon lr mount o rsturnts oul sv Jon s tm. T qury sown low ssontpostrsqlsyntx. SELECT FRM Rsturnt R WHERE R.stn <8. AND R.pr <8.5 RDER BY (t) T lst o rsturnts n tr sors r sown n Tl 1. Ts rsturnts n rprsnt n two-mnsonl sp s sown n Fur 1(). T Alto, E, s top-1 nswr to t qury wt sor o 3.2 n lv Grn, D, s top-2nswrtotqurywtsoro4..snrsturnts A, F, G, I, n J v r vlus or stn n pr, ty o not stsy t rqurmnts prov y Jon. Tus, t sors or ts rsturnts r not lult. To nswr t top-k qurs ntly, uln n nx y ssn t sust o ts s n. T skyln mtos r rprsnttv mtos or nswrn t top-k qurs y onstrutn skyln s n nx. Ts mtos xprss t tupls s ots n -mnsonl sp n tn onstrut skyln. Hr, s t numr o ttruts o ts. T skyln mtos r nt or qurs n ts wt lr numr o ttruts n t. In Fur 1(), t rtnulr lk ln, ompos o lk ponts, rprsnts t skyln. T skyln ponts o not omnt otr. W n nswr top-k qurs only y rn t skyln ponts, sn t skyln n onsr s n nx. T sot-ltr-skyln (SFS) lortm [6], w s t stt-o-t-rt mto, prsorts t ots y lultn ntropy vlu o ot. T nl-s sp prttonn (ABSP) [7] n pln-prot-prlll-skyln () [8] prtton t sp nto numr o surons n orr to ru t omputn tm. mprovs ABSP y prttonn t sp nto numr o sps usn yprpln proton. Howvr, s nx uln tm n -mnsonl tss. In ts ppr, w propos nw skyln mto or ntly nln top-k qurs n IoT ppltons. Ts ppr ouss on t tvnss o r-s prttonn. Mor prsly, t ontrutons w mk n ts ppr r s ollows. () Wproposnwskylnmto(llGr-) or ntly nln top-k qurs n IoT ppltons. T propos mto rst prorms r-s prttonn on t sp n tn prttons t on

3 Appl Mtmts 3 n usn yprpln proton. Ts rus t tm omplxty o t. () W sow t prormn vnts o t Gr- trou t omprson o t nx uln tm n numr o omntn ots ompr to. T rst o ts ppr s ornz s ollows. Ston 2 srs xstn work rlt to ts ppr. Ston 3 prsnts t propos mto or omputn Gr- n Ston 4 monstrts t rsults o prormn vluton. Ston5 summrzs n onlus t ppr. 2. Rlt Work In ts ston, w suss t xstn ltrtur. In Ston 2.1, w rvw t mnmnt solutons n IoT, n, n Ston2.2, w xpln t nx uln mtos or top-k qurs Dt Mnmnt Mtos n IoT. Gnrlly spkn, ll tns on t IoT my nrt u mount o t tt ontns rnt kns o usul normton. Howvr, ow to nl su t n ow to rtrv t vlul normton v om ot rsr top n rnt yrs. Svrl nx uln mtos or nln mssv mount oiottrpropos.mtl.[9] propos n upt n qury nt nx rmwork (UQE-Inx) s on kyvlu stor tt n support ot multmnsonl qury n nsrt trouput. In orr to tvly ru t nx upt tms n rs t nx mntnn ost, t utors propos ynm t prtton strty tt nmksurttttsvnlystrutnto ronnhbsnttttslosntmnsp mnson s usully stor n t sm rons. In orr to rss t prolm o mnsonlty n IoT t, Hun t l. [1] propos ynm skyln u (SKYCUBE) omputton to ntly ln t omputton upt n osts n IoT. T utors propos n nt r-s ADSCIT (lortm or ynm SKYCUBE omputton n t Intrnt o Tns) w onssts o two mouls: ontnuous mntnn moul (CMM), w nrmntlly upts t nonpsuo ots, n prorssv omputton moul (PCM), w n rplyotntskylnuromtuptnonpsuo ots. In orr to ntrt t propos two mouls, r-s vluton mto tt uss rulr r nx s propos. Elkr t l.[11] survy t t mnmnt solutons tt r propos or IoT n propos t mnmnt rmwork tt tks nto onsrton t rwks o xstn ppros. T propos rmwork pts rt, t n sours ntr ppro to lnk vrs tns wt tr unn o t to t potntl ppltons nsrvs.dtmnntnolosnlsousto sovr t n normton n t t o IoT, w nustomprovtprormnotsystmor to nn qulty o srvs ts nw nvronmnt n prov [12]. Ts t l. [12] survyrsronowto onnt t mnn tnolos to t IoT, w nlu lustrn, lsston, n rqunt pttrns mnn tnolos, rom rnt prsptv. T utors lso suss ns, potntls, opn ssus, n utur trns o pplyn t mnn to t IoT Inx Buln Mtos or Top-k Qurs. To onstrut n nx ntly, skyln n onvx ull mtos r rprsnttv mtos. Ts mtos onstrut n nx s lst o lyrs n onsst o ots w r not omnt y otr. T omputn ost o skyln mtos s mu lowr tn tt o onvx ull mtos; owvr, t numr o ots n lyr o skyln mtos s mu lrr tn tt o onvx ull mtos. Tus, t skyln mtos r mnly us n t ppltons wr nsrton, upt, n lton oprtons r rquntly ourrn on ots. Sn su ppltons n to onstrut skyln mor rquntly, ty rqur smll omputn tm. n t otr n, ots n onvx ull mtos r not upt otn. Tus, ts mtos r us n t ppltons wr top-k qury prossn s prorm. Ts s us lyr n onvx ull mtos onssts o smll numr ots, w rsults n rp prossn o top-k qurs. In ts ppr, w ous on run t nx onstruton o skyln n w t s rquntly upt Skyln Mtos. Tskylnmtosrusulwn nswrn top-k qurs y ssn only sust o t ts. Ts mtos v n vnt o low nx uln ost. T skyln oprton ws rst ntrou y Kölr t l. [8] n tr v n numr o vrtons o t. T t sp prttonn tnqu s us n mny skyln mtos or rly prunn ots w r not nlu n skyln. Tr r svrl lortms or onstrutn skyln tt pply sp prttonn tnqu. Gr-s t sp prttonn s n ommonly us n strut n prlll skyln prossn [8]. T nls sp prttonn ppro (ABSP) [7] spropos y usn yprsprl oornts o t ots n mprovs r-s sp prttonn. Kölr t l. [8] propos novl ppro ll, w rus t omputn tm o ABSP y oorntn t ots usn yprpln proton. Tr r lso otr lortms or onstrutn skyln n t rprsnttv mtos r lok nst loops (BNL) [13], SFS [6], n lnr lmnton sort or skyln (LESS) [14].BNLsquntllyrstnputrltonnsvsn wnoww. Wnnoto s r, t s ompr to ots n w. I n ot n w omnts o, BNL lmnts o. trws,o omnts som ots n w; tsr lt rom w n o s to [13]. T SFS lortm [6] mprovs BNL y prsortn t nput rlton orn to t ntropy vlu o ot. LESS s n mprovmnt o SFS tt ssntlly omns spts o numr o t stls lortms [14]. LESS srs som omntn ots rlr; tus ts s t vnt o run t numr o prws omprsons twn t ots tn

4 4 Appl Mtmts () Approxmt skylnn stp () Gr-s prttonn stp () Hyprpln-s prttonn stp () Lol skylnn stp () Mrn stp Fur 2: T ovrll prour or prossn Gr- n t two-mnsonl t sp.

5 Appl Mtmts 5 X 3 () Gr-s prttonn n two-mnsonl t sp () Gr-s prttonn n tr-mnsonl t sp Fur 3: T xmpl o r-s prttonn Inx uln tm (s) Dt sz N (K) ndc ( 1, ) Dt sz N (K) Gr- Gr- () Computn tm s N s vr ( = 8) () ndc s N s vr ( = 8) Fur 4: T omprson o t omputn tm n ndc s N s vr rlt to Exprmnt 1. SFS. Howvr, t numr o omprsons s stll lr. Tr lso s n rown ntrst n strut [15, 16] n prlll [17, 18] skyln omputton ltly tr Mtos. T onvx ull mtos onstrut t lyr o ots n onvx ull sp n sr otr ots. T lyr sz o onvx ull mtos s smllr tn tt o skyln mtos; owvr, t nx uln tm o onvx ull mtos s r tn tt o skyln mtos. T rprsnttv onvx ull mtos r NIN [19] n HL-Inx [5]. NIN [19] uls onvx ull s n nx y onstrutn ounry wt t ots. Tt s, t ots o t rst lyr nrl t otr ots. NINulssonlyrntsmmnnrnnlly onstruts lst o lyrs s rsult. HL-Inx [5] uls onvx ull s NIN os n sorts lsts tonlly or rtrvn top-k rsults ntly. In orr to ru t nx uln tm o onvx ull mtos, tr r som mtos tt omn onvx ull n skyln mtos. For xmpl, Im t l. [2] propos t pproxmt onvx skyln (AppCS) mto tt onstruts skyln ovr t ntr ots n tn prttons t. Furtr, AppCS uls n pproxmt onvx ull n prtton ron wt vrtul ots. Anotr mto tt ouss on run nx uln tm o onvx ull s propos n [21]. T utors propos mto ll pproxmt onvx ull nx (CH-Inx) tt omputs t skyln ovr t ntr st o ots, prttons t ron nto multpl surons to ru t omputn tm o onvx ull n ll orns, n tn omputs t onvx ull n suron. 3. Gr- In ts ston, w xpln t propos mtos, Gr-. As xpln n Ston 2.1, t [8] mprovs

6 6 Appl Mtmts 1 1 Inx uln tm (s) Inx uln tm (s) SFS Gr- SFS Gr- () Computn tm s s vr (N = 1 K) () Computn tm s s vr (N = 1 K) 8 Inx uln tm (s) SFS Gr- () Computn tm s s vr (N = 1 K) Fur 5: T omprson o t omputn tm o Gr- n SFS s n N r vr rlt to Exprmnt 2. t nxn uln tm o ABSP [7]. Howvr, s nx uln tm n -mnsonl tss. T Gr- rus t tm omplxty o t. T Gr-sonstrutyvstpsssownnFur2: () pproxmt skylnn stp, () r-s prttonn stp, () yprpln-s prttonn stp, () lol skylnn stp, n () mrn stp. For t onvnn o t xplnton, Fur 2 sows t prour o prossn Gr- n two-mnsonl ron. W xpln stp n tl rom Stons 3.1 to Approxmt Skylnn Stp. In t rst stp, Gr- onstruts pproxmt skyln. Ts stp s sown n Fur 2(). Computn t xt skyln o ll tupls st T n xpnsv, sn tupl soul ompr to mny otr tupls. Howvr, w n prun svrl tupls wt t w omprsons. W prun t ots y lultn t ntropy vlu o ot. W slt svrl tupls, w v low ntropy vlu, n tn mk smll st S T wt tos tupls. By t smll st S, somtuplsnt r omnt y S, n tos tupls n lmnt sly. Sn w pk t tupls orn to ntropy vlu, w n sr mor tupls. Fnlly, w n t pproxmt skyln. Importntly, or x sz S, omputn t pproxmt skyln n prorm n lnr tm wt snl pss ovr t tst [8] Gr-Bs Prttonn Stp. In t mor stp tt s r-s prttonn stp, Gr- prttons t t sp nto susps usn r-s prttonn tnqu. A r s somtn w s n pttrn o strt lns tt ross ovr otr, ormn squrs. Mny ppltons r usn r-s tnqu, sn t s smpl n s low omputn ost [22 24]. T r-s prttonn sm s s on rursvly vn som mnson o t t sp nto two prts[7]. T omputn tm o r-s prttonn s lowr tn otr prttonn tnqus, us r-s prttonn s smpl n p to omput. Tus, w prtton ots, w r otn rom pproxmt skylnn stp nto sps wt r-s prttonn tnqu. Fur 3() sows t xmpl o r-s prttonn n two-mnsonl t sp, n tr-mnsonl xmpl s sown n Fur 3().

7 Appl Mtmts 7 Inx uln tm (s) Inx uln tm (s) Gr- () Computn tm s s vr (N = 1 K) Gr- () Computn tm s s vr (N = 1 K) Inx uln tm (s) Gr- () Computn tm s s vr (N = 1 K) Fur 6: T omprson o t omputn tm o t Gr- n s n N r vr rlt to Exprmnt Hyprpln-Bs Prttonn Stp. In t yprplns prttonn stp, Gr- prttons sp nto susps usn yprpln-s prttonn, w s propos n [8]. W rst lult t ormul o t yprpln su s x 1 +x 2 + +x =1. Nxt, w prot tupls onto t yprpln, n (1) sows t lulton o proton. Fnlly w prtton sp, w onssts o prot tupls, nto susps: (x 1 x ) (x 1 x ) 1 x 1 + +x. (1) 3.4. Lol Skylnn Stp. In t lol skylnn stp, Gr- omputs t lol skyln n susp.w ll lol skyln n susp s suskyln n us SFS lortm [6] or omputn suskyln. For t onstruton o lol skyln, t omntn lulton, w trmnswtrtotsntskylnornot,soul omput twn two ots. Gr- ltrs out t ots y r-s prttonn stp, n, tus, t numr o omntn lulton rss Mrn Stp. In t lst stp, Gr- omns t suskylns n susp. W ul lyr y mrn t suskylns. Sn Gr- omputs suskyln ponts on n, t omns t suskylns n uls rsult lyr wtout losn tupls n ovrlppn. 4. Prormn Evluton In ts ston, w rst xpln t t n nvronmnt n Ston 4.1 n tn prsnt t rsults o xprmnts n Ston Exprmntl Dt n Envronmnt. W v mplmnttproposmtousnc++.wonutllt xprmnts on n Intl 5-76 qu or prossor runnn t 2.8 GHz Lnux PC wt 16 GB o mn mmory. W us t unorm tst or ll o our xprmnt t. W us 1 K, 1 K, n 1 K t sz. W xprmnt our t n two trou nn mnsons Rsult o Exprmnts. W ompr t omputn tm n t ndc (numroomntonlulton)otgr- wt t xstn mtos [8]nSFS[6]. W us t wll lok tm s t msur o t omputn tm. W msur t omputn tm ndc on t syntt tst wl vryn t t sz N n t mnson.

8 8 Appl Mtmts ndc ( 1) Gr- ndc ( 1) Gr- () ndc s s vr (N = 1 K) ndc ( 1) Gr- () ndc s s vr (N = 1 K) () ndc s s vr (N = 1 K) Fur 7: T omprson o t ndc n n N r vr rlt to Exprmnt 3. T rsult o t skyln onstrut y Gr- s xtly t sm s. Gr- mprovs t nx uln tm o n lr n -mnsonl tst. Wn t s 1 K sz n unr sx ttruts, t nx uln tm o Gr- s lttl r tn, us o prttonn stp. T numr o ltr tupls n Gr- s smlr to n t smll n low-mnsonl tst. Howvr, Gr- onstruts n nx mu qukly n lr n -mnsonl tst s sown n xprmnts. Exprmnt 1. Computn tm n ndc s t sz N s vr. Fur 4() sows t omputn tm o Gr- n s N s vr rom 1 K to 1 K. T rsult nrss n lo sl s sown n Fur 4. T omputn tm o t Gr- mprovs y tms ovr t. Fur 4() sows t ndc o Gr- n s N s vrrom1k to 1K. T ndc o Gr- mprovs tms ovr t. Exprmnt 2. Computn tm s mnson n t sz N r vr. Furs 5(), 5(), n5() sow t omputn tm o Gr- n s s vr rom 2 to 9 n N s vr rom 1 K to 1 K. T rsult nrss n lo sl s sown n Fur5.Fur5() sows t omputn tm o t Gr- mprovs y tms ovr t s s vr n N s 1 K. Fur 5() sows t omputn tm o t Gr- mprovs y tms ovr t s s vr n N s 1 K. Fur 5() sows t omputn tm o t Gr- mprovs y tms ovr t s s vr n N s 1 K. In orr to sow t prs rn twn Gr- n, w onut t xprmnts sown n Fur 6. Exprmnt 3. T ndc s mnson n t sz N r vr. Furs 7(), 7(), n 7() sow t ndc o Gr- n s s vr rom 2 to 9 n N s vr rom 1 K to 1 K. T rsult nrss n lo sl s sown n Fur 7. Fur 7() sows t ndc o t Gr- mprovs y tms ovr t s s vr n N s 1 K. Fur 7() sows t ndc o t Gr- mprovs y tms ovr t s s vr n N s 1 K. Fur 7() sows t ndc o t Gr-

9 Appl Mtmts 9 mprovs y tms ovr t s s vr n N s 1 K. 5. Conluson As mor n mor snsors t onnt to t Intrnt, t IoT ppltons nrt normous mounts o t. In orr to solv ts prolm, n ts ppr, w v propos to us top-k qury prossn to n t st rsults mon vst mount o t. In orr to ntly nl top-k qurs, w v propos nw skyln mto ll Gr-, w prorms r-s prttonn rst on t sp n tn prttons t on n usn yprpln proton. W v ompr t propos mto wt t stt-o-t-rt mtos, su s n SFS. T rsults o xprmnts monstrt svrl tms mprovmnt n most ss. Conlt o Intrsts T utors lr tt tr s no onlt o ntrsts rrn t pulton o ts ppr. Aknowlmnt Ts rsr ws support y t Bs Sn Rsr Prorm trou t Ntonl Rsr Founton o Kor (NRF) un y t Mnstry o Euton, Sn n Tnoloy ( ). Rrns [1]C.Prr,A.Zslvsky,C.H.Lu,M.Compton,P.Crstn, n D. Gorkopoulos, Snsor sr tnqus or snsn s srv rttur or t ntrnt o tns, IEEE Snsors Journl, vol. 14, no. 2, pp , 214. [2] C.Zu,Q.Zu,C.Zuzrt,nW.M, Dvlopnynm mtrlz vw nx or ntly sovrn usl vws or prorssv qurs, Inormton Prossn Systms,vol.9,no.4,pp ,213. [3] Y. Prk, K. Wn, B. S. L, n W. Hn, Ent vluton o prtl mt qurs or XML oumnts usn normton rtrvl tnqus, n Prons o t Dts Systms or Avn Appltons (DASFAA 5),pp ,Aprl25. [4] R.M.Hwn,S.K.Km,S.An,nD.W.Prk, Trtturl pttrn o ly xtnsl systm or t synronous prossn o lr mount o t, Inormton Prossn Systms,vol.9,no.4,pp ,213. [5]J.Ho,J.Co,nK.Wn, Tyr-lyrnx: synr ppro to nswrn Top-k qurs n rtrry susps, n Prons o t 26t ntrntonl Conrn on Dt Ennrn, pp , Mr 21. [6]J.Comk,P.Gory,J.Gryz,nD.Ln, Skylnwt prsortn, n Prons o t 19t Intrntonl Conrn on Dt Ennrn, pp , Mr 23. [7] A. Vlou, C. Doulkrs, n Y. Kots, Anl-s sp prttonn or nt prlll skyln omputton, n Prons o t 28 ACM SIGMD Intrntonl Conrn on Mnmnt o Dt, pp , Jun 28. [8] H. Kölr, J. Yn, n X. Zou, Ent prlll skyln prossn usn yprpln protons, n Prons o t 211 ACM SIGMD Intrntonl Conrn on Mnmnt o t, pp , Jun 211. [9] Y. M, J. Ro, W. Hu t l., An nt nx or mssv IT t n lou nvronmnt, n Prons o t 21st ACM ntrntonl onrn on Inormton n knowl mnmnt (CIKM 12), pp , 212. [1] Z. Hun, Y. Xn, D. Wn, n B. Zn, Ent ynm SKYCUBE omputton n t ntrnt o tns, n Prons o t Intrntonl Conrn on Computr n Communton Tnolos n Arultur Ennrn (CCTAE 1), pp , Jun 21. [11] M. A. Elkr, M. Hyn, n N. A. Al, Dt mnmnt or t ntrnt o tns: sn prmtvs n soluton, Snsors,vol.13,no.11,pp ,213. [12] C. W. Ts, C. F. L, M. C. Cn, n L. T. Yn, Dt mnn or ntrnt o tns: survy, IEEE Communtons Survys n Tutorls,vol.16,no.1,pp.77 97,214. [13] S. Börzsöny, D. Kossmnn, n K. Stokr, T skyln oprtor, n Prons o t 17t Intrntonl Conrn on Dt Ennrn,pp ,Aprl21. [14] P. Gory, R. Sply, n J. Gryz, Mxml vtor omputton n lr t sts, n Prons o t 31st Intrntonl Conrn on Vry Lr Dt Bss, pp , Sptmr 25. [15] K. Hos, C. Lmk, n K.-U. Sttlr, Prossn rlx skylns n PDMS usn strut t summrs, n Prons o t 26 Conrn on Inormton n Knowl Mnmnt,pp ,Novmr26. [16] S.Wn,B.C.o,A.K.H.Tun,nL.Xu, Entskyln qury prossn on pr-to-pr ntworks, n Prons o t 27 Intrntonl Conrn on Dt Ennrn, pp , Aprl 27. [17] A. Cosy-Lozno, A. Ru-Cpln, n N. Z, Prlll omputton o skyln qurs, n Prons o t 21st Intrntonl Symposum on H Prormn Computn Systms n Appltons,pp.1 7,My27. [18]P.Wu,C.Zn,Y.Fn,B.Y.Zo,D.Arwl,nA.E. A, Prlllzn skyln qurs or sll struton, n Prons o t 26 Conrn on Extnn Dts Tnoloy, pp , 26. [19] Y. C. Cn, L. Brmn, V. Cstll, C. S. L, M. L. Lo, n J. R. Smt, T onon tnqu: nxn or lnr optmzton qurs, n Prons o t 2 ACM SIGMD Intrntonl Conrn on Mnmnt o t, pp , 2. [2] S. Y. Im, K. E. L, A. Nsrnov, J. S. Ho, n Y. H. Prk, Approxmt onvx skyln: prtton lyr-s nx or nt prossn top-k qurs, Knowl-Bs Systms,vol.61,pp.13 28,214. [21] S. Y. Im, A. Nsrnov, n Y. H. Prk, An nt nx uln lortm or slton o rtor no n wrlss snsor ntworks, Intrntonl Dstrut Snsor Ntworks, vol. 214, Artl ID 52428, 8 ps, 214. [22] J. W. K. Gnnr, K. Ezr, n E. B. Rsn, Smrt r s tm nt utntton sm or lol r omputn, Humn-Cntr Computn n Inormton Sns,vol.3,no. 16, pp. 1 14, 213.

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11 Avns n prtons Rsr Avns n Dson Sns Appl Mtmts Alr Prolty n Sttsts T Snt Worl Journl Intrntonl Drntl Equtons Sumt your mnusrpts t Intrntonl Avns n Comntors Mtmtl Pyss Complx Anlyss Intrntonl Mtmts n Mtmtl Sns Mtmtl Prolms n Ennrn Mtmts Dsrt Mtmts Dsrt Dynms n Ntur n Soty Funton Sps Astrt n Appl Anlyss Intrntonl Stost Anlyss ptmzton