7064558-ng-dng-Th-Nghim-Mobile-Agent-vao-xay-dng-Workflow

Li cm nChng em xin chn thnh cm n cc thy c hng dn tn tnh gip v truyn t kin thc chng em c th hon thnh lun vn ny. c bit, chng em xin gi li cm n su sc nht n thy Cao ng Tn - ngi ng vin v gip cho chng em nhit tnh trong qu trnh thc hin lun vn. Chng em cng xin gi li cm n n tt c cc thy c trong khoa Cng ngh thng tin to iu kin tt cho chng em lm vic, hc tp v nghin cu trong sut qu trnh thc hin lun vn. Cm n tt c cc bn hc cng kha nhit tnh chia s kinh nghim v nhng kin thc qu bu, gip chng ti c th lm tt cng vic ca mnh. Mc d c gng hon thnh lun vn vi tt c s n lc ca bn thn, nhng lun vn chc chn khng trnh khi nhng thiu st, knh mong qu Thy C tn tnh ch bo. Mt ln na xin gi n tt c mi ngi li cm n chn thnh nht.

i

ng dng th nghim Mobile Agent vo xy dng Workflow

NHN XT CA GIO VIN HNG DN

........................................................................................ ........................................................................................ ........................................................................................ ........................................................................................ ........................................................................................ ........................................................................................ ........................................................................................ ........................................................................................ ........................................................................................ ........................................................................................ ........................................................................................ ........................................................................................ ........................................................................................ ........................................................................................ ........................................................................................ ........................................................................................ ........................................................................................ .........................................................................Nguyn Hong Linh Phng Nguyn Vn Thoi ii GVHD: GVC Cao ng Tn


NHN XT CA GIO VIN PHN BIN

........................................................................................ ........................................................................................ ........................................................................................ ........................................................................................ ........................................................................................ ........................................................................................ ........................................................................................ ........................................................................................ ........................................................................................ ........................................................................................ ........................................................................................ ........................................................................................ ........................................................................................ ........................................................................................ ........................................................................................ ........................................................................................ ........................................................................................ ........................................................................Nguyn Hong Linh Phng Nguyn Vn Thoi iii GVHD: GVC Cao ng Tn


Mc lcMc lc hnh ________________________________________________________ 1 Mc lc bng________________________________________________________ 3 Bng ch gii _______________________________________________________ 5 Tm tt lun vn _____________________________________________________ 6 Chng 1: Gii thiu ti ____________________________________________ 7 Chng 2: Khi nim v nguyn l hot ng ca Mobile Agent ______________ 91. Tng qut v software agent _____________________________________________91.1. Ngun gc _______________________________________________________________ 9 1.2. Khi nim ______________________________________________________________ 10 1.3. Cc tnh nng ca agent: ___________________________________________________ 11 1.4. Phn loi agent __________________________________________________________ 12

2. Mobile Agent v nguyn l hot ng_____________________________________142.1. Khi nim Mobile Agent___________________________________________________ 2.2. Tnh cht mobile agent:____________________________________________________ 2.3. Mt s h thng MA: _____________________________________________________ 2.4. Nguyn l hot ng ______________________________________________________ 2.5. Agent Host : ____________________________________________________________ 2.6. ch li ca mobile agent ___________________________________________________ 2.7. Mi trng ng dng mobile agent___________________________________________ 2.8. Bo mt ________________________________________________________________ 3.1. Khi nim ______________________________________________________________ 3.2. Tnh cht _______________________________________________________________ 3.3. Cch ci t v s dng Aglet trn mi trng Window __________________________ 3.4. Aglet LifeCycle __________________________________________________________ 3.5. Aglet API ______________________________________________________________ 14 15 15 19 25 26 27 29 30 31 31 38 40

3. Tng qut v Aglet ____________________________________________________30

Chng 3: Khi nim v cc m hnh WorkFlow _________________________ 431. Khi nim ___________________________________________________________44 2. ch li p dng workflow: ______________________________________________44 3. Cc dng workflow ____________________________________________________453.1. Cc dng n gin: _______________________________________________________ 45 3.2. Cc dng nng cao: _______________________________________________________ 48

4. Kt hp k thut MA v workflow _______________________________________564.1. ch li _________________________________________________________________ 56 4.2. Cc hng nghin cu tch hp h thng mobile agent v workflow _________________ 56

Chng 4: Xy dng ng dng ________________________________________ 581. Gii thiu ng dng ___________________________________________________581.1. C cu t chc trong c quan:_______________________________________________ 1.2. Cc cch gii quyt vn :_________________________________________________ 1.3. Yu cu c bn ca h thng: _______________________________________________ 1.4. Cc i tng s dng h thng:_____________________________________________ 1.5. Cu trc h thng ________________________________________________________ 58 60 62 62 62

Nguyn Hong Linh Phng Nguyn Vn Thoi

iv

GVHD: GVC Cao ng Tn


1.6. Kin trc h thng: _______________________________________________________ 1.7. Quy trnh nghip v ca tng i tng s dng:________________________________ 1.8. Yu cu c th cc chc nng _______________________________________________ 1.9. Cch thc x l vn bn ___________________________________________________ 1.10. Vn merge d liu: ____________________________________________________ 1.11. Cc x l tnh hung _____________________________________________________

64 65 66 66 68 70

2. Phn tch, thit k ng dng ____________________________________________732.1. Phn tch module FormDesigner _____________________________________________ 73 2.2. Thit k module Form Designer _____________________________________________ 82 2.3. Phn tch module WorkFlow Designer ________________________________________ 99 2.4. Thit k chng trnh WorkFlow Designer_____________________________________110 2.5. Phn tch chng trnh Manager Agent________________________________________119 2.6. Thit k chng trnh Agent Manager ________________________________________123

Chng 5: Ci t v th nghim _____________________________________ 1381. Ci t h thng _____________________________________________________1381.1. Ci t v s dng Form Designer ___________________________________________138 1.2. Ci t v s dng Workflow Designer _______________________________________140 1.3. Ci t v s dng Agent Manager ___________________________________________141

2. Th nghim h thng _________________________________________________1452.1. Nhn xt chng trnh Manager Agent ________________________________________145 2.2. Nhn xt h thng ________________________________________________________145

Chng 6: nh gi kt qu _________________________________________ 1461. nh gi lun vn ____________________________________________________146 2. nh gi ng dng ___________________________________________________1462.1. Kt qu t c _________________________________________________________146 2.2. Mt vi hn ch ca h thng _______________________________________________147

3. Hng pht trin ____________________________________________________147 4. Kt lun ____________________________________________________________148


v

GVHD: GVC Cao ng Tn


Mc lc hnhHnh 1: Agent Phng php lp trnh mi .......................................................................10 Hnh 2: Phn loi agent theo mc ch ................................................................................13 Hnh 3: K thut Pull code Bc 1....................................................................................19 Hnh 4: K thut Pull code Bc 2....................................................................................20 Hnh 5: K thut Pull code Bc 3....................................................................................20 Hnh 6: K thut Push code Bc 1 ..................................................................................21 Hnh 7: K thut Push code Bc 2 ..................................................................................21 Hnh 8: K thut Autonomous code Bc 1 .....................................................................21 Hnh 9: K thut Autonomous code Bc 2 .....................................................................22 Hnh 10: Vng i agent......................................................................................................23 Hnh 11: Gii nn aglets-2.0.2.jar........................................................................................33 Hnh 12: Ci t platform ....................................................................................................35 Hnh 13: Ci t chnh sch bo mt ...................................................................................36 Hnh 14: ng nhp server Tahiti........................................................................................37 Hnh 15: Mn hnh Server Tahiti.........................................................................................38 Hnh 16: Vng i Aglet .....................................................................................................39 Hnh 17: Aglet API ..............................................................................................................40 Hnh 18: M hnh Workflow Tun t..................................................................................45 Hnh 19: M hnh Workflow song song ..............................................................................46 Hnh 20: M hnh workflow ng b ha ..........................................................................46 Hnh 21: M hnh workflow Chn lai tr..........................................................................47 Hnh 22: M hnh workflow Trn n gin ........................................................................47 Hnh 23: M hnh workflow Chn a nhnh.......................................................................48 Hnh 24: M hnh workflow Trn ng b ha...................................................................49 Hnh 25: M hnh workflow Trn a nhnh........................................................................49 Hnh 26: M hnh workflow Discrimator ............................................................................50 Hnh 27: M hnh workflow Cc vng lp ty .................................................................50 Hnh 28: M hnh workflow Ct mc .................................................................................55 Hnh 29: C cu t chc trong c quan ...............................................................................58 Hnh 30: V d 1 workflow n gin...................................................................................60 Hnh 31: Kin trc h thng ................................................................................................64 Hnh 32: Merge n gin.....................................................................................................68 Hnh 33: M t li trong qu trnh vn hnh workflow.......................................................72 Hnh 34: Use Case Form Designer ......................................................................................73 Hnh 35: Lung d liu to mi form trong Form Designer ...............................................75 Hnh 36: Lung d liu m form trong Form Designer ......................................................75 Hnh 37: Lung d liu lu form trong Form Designer ......................................................76 Hnh 38: Lung d liu thm control trong Form Designer................................................77 Hnh 39: Lung d liu chnh sa control trong Form Designer ........................................78 Hnh 40: Lung d liu chnh sa control trong Form Designer ........................................79 Hnh 41: S quan h gia cc lp c bn trong chng trnh ........................................80 Hnh 42: Thit k mn hnh chnh module Form Designer .................................................84 Hnh 43: Thit k mn hnh About ......................................................................................90


1

GVHD: GVC Cao ng Tn


Hnh 44: Thit k mn hnh Save ........................................................................................91 Hnh 45: Thit k mn hnh chn Border ............................................................................93 Hnh 46: Thit k mn hnh chn Font ................................................................................95 Hnh 47: Thit k mn hnh chn hnh nh .........................................................................97 Hnh 48: Thit k mn hnh Preview ...................................................................................98 Hnh 49: Use Case WorkFlow Designer..............................................................................99 Hnh 50: Lung d liu cho to mi workflow trong Workflow Designer.......................101 Hnh 51: Lung d liu cho m workflow trong Workflow Designer..............................101 Hnh 52: Lung d liu cho lu workflow trong Workflow Designer..............................102 Hnh 53: : Lung d liu cho thm 1 node vo workflow trong Workflow Designer ......103 Hnh 54: Lung d liu cho chnh sa node trong Workflow Designer ...........................104 Hnh 55: Lung d liu cho xa node trong Workflow Designer .....................................105 Hnh 56: Lung d liu cho thm ng i vo workflow trong Workflow Designer.....106 Hnh 57: : Lung d liu cho xa ng i trong Workflow Designer ............................107 Hnh 58: Lung d liu cho chn form cho node trong Workflow Designer ...................108 Hnh 59: Thit k mn hnh Workflow Designer ..............................................................112 Hnh 60: Thit k mn hnh About cho module Workflow Designer ...............................116 Hnh 61: Thit k mn hnh Save cho module Workflow Designer..................................117 Hnh 62: Use Case Manager Agent ...................................................................................119 Hnh 63: Lung d liu cho chn workflow trong Agent Manager ..................................120 Hnh 64: Lung d liu cho thc thi workflow trong Agent Manager..............................121 Hnh 65: Lung d liu cho ng nhp trong Workflow Agent........................................121 Hnh 66: Lung d liu cho chn vn bn XML trong Workflow Agent .........................122 Hnh 67: Lung d liu cho lu tm trong Workflow Agent ............................................122 Hnh 68: Lung d liu cho hon thnh bo co trong Workflow Agent .........................123 Hnh 69: Thit k mn hnh Agent Manager .....................................................................124 Hnh 70: Thit k mn hnh Running Window..................................................................128 Hnh 71: Thit k mn hnh Workflow Agent...................................................................130 Hnh 72: Mn hnh Form Designer....................................................................................139 Hnh 73: mn hnh Workflow Designer ............................................................................140 Hnh 74: Mn hnh server Tahiti........................................................................................142 Hnh 75: Mn hnh to Aglet .............................................................................................142 Hnh 76: Mn hnh Agent Manger.....................................................................................143 Hnh 77: Mn hnh Workflow Agent.................................................................................144


2

GVHD: GVC Cao ng Tn


Mc lc bngBng 1: Danh sch nghip v cho chng trnh thit k form Bng 2: Danh sch cc lp i tng mn hnh Bng 3: Cc i tng th hin mn hnh design Bng 4: Bng m t cc i tng mn hnh con Bng 5: Bng m t chi tit cc i tng th hin ControlList Bng 6: Bng m t cc bin c ca Control List Bng 7: Bng m t chi tit cc i tng th hin PropertyList Bng 8: Bng m t cc bin c ca mn hnh design MH_MAIN Bng 9: Bng m t mn hnh About Bng 10: Bng m t mn hnh MH_SAVE Bng 11: Bng m t cc bin c ca mn hnh MH_SAVE Bng 12: Bng m t mn hnh MH_BORDER Bng 13: Bng m t cc bin c ca mn hnh chn Border Style Bng 14: Bng m t mn hnh chn Font Bng 15: Bng m t cc bin c ca mn hnh chn Font Bng 16: Bng m t mn hnh chn hnh nh Bng 17: Bng m t cc bin c ca mn hnh chn hnh Bng 18: Bng m t mn hnh xem trc Bng 19: Danh sch nghip v cho chng trnh thit k workflow Bng 20: Danh sch cc lp i tng mn hnh chnh Bng 21: Bng m t cc i tng th hin mn hnh Workflow Designer Bng 22: Bng m t cc bin c ca mn hnh Workflow Designer Bng 23: Bng m t cc i tng th hin mn hnh control Bng 24: Bng m t cc bin c ca mn hnh Control Bng 25: Bng m t chi tit cc i tng th hin Bng 26: Bng m t mn hnh About Bng 27: Bng m t mn hnh Save Bng 28: Bng m t cc bin c ca mn hnh Save Bng 29: Danh sch cc nghp v cho chng trnh ManagerAgent Bng 30: Danh sch cc i tng th hin trong mn hnh Agent Manager Bng 31: Danh sch cc bin c trong mn hnh Agent Manager Bng 32: Danh sch cc hm x l trong mn hnh Agent Manager Bng 33: Danh sch cc i tng th hin trong mn hnh Bng 34: Danh sch cc bin c trong mn hnh Running Workflow Bng 35: Danh sch cc hm x l trong mn hnh Running Workflow Bng 36: Danh sch cc i tng th hin trong mn hnh Workflow Agent Bng 37: Danh sch cc bin c trong mn hnh Workflow Agent Bng 38: Danh sch cc hm x l trong mn hnh Workflow Agent Bng 39: Danh sch cc bin thnh phn ca Lp ManagerAgent Bng 40: Danh sch hm thnh phn Lp ManagerAgent Bng 41: Danh sch cc bin thnh phn ca lp Workflowagent Bng 42: Danh sch hm thnh phn ca lp Workflowagent Bng 43: Danh sch cc bin thnh phn ca lp Nagent 73 83 84 85 86 87 89 89 91 91 92 93 94 95 96 97 97 98 99 111 112 113 115 115 116 117 117 118 119 124 126 127 128 129 129 130 131 132 134 134 135 135 136


3

GVHD: GVC Cao ng Tn


Bng 44: Danh sch hm thnh phn ca lp Nagent

137


4

GVHD: GVC Cao ng Tn


Bng ch giiClient-Server Peer-to-peer ARPANET UML Merge XML module IP LAN Platform ASDK bandwidth code Editor sandbox TCP/IP Release JDK Freeware Internet M hnh mng, trong c 1 my trung tm, chu trch nhim x l cc yu cu do cc my con a ti Mng ngang hng, cc my tnh c chc nng nh nhau trong mng Mng my tnh u tin, thuc b quc phng M Mt ngn ng phn tch thit k Trn Ngn ng nh du m rng Nhng phn mm c pht trin ring tch hp vo 1 h thng ln a ch Mng ni b c phm vi hp Nn tng cho ng dng b th vin cho Aglet Bng thng ng truyn mng M ngun trnh son tho m hnh bo mt ca Java Giao thc Internet Phin bn B th vin lp trnh cho Java Phn mm min ph Mng my tnh ln nht hin nay, ni kt my tnh trn tan th gii


5

GVHD: GVC Cao ng Tn


Tm tt lun vnLun vn gm cc chng sau y: Chng 1: Gii thiu ti Chng 2: Khi nim v nguyn l hot ng ca Mobile Agent Gii thiu v ngun gc, khi nim, phng thc hot ng, cc ch li khi s dng v cc mi trng p dng mobile agent. Ngoi ra, phn ny cn gii thiu v Aglet mobile agent trong mi trng Java do IBM cung cp Chng 3: Khi nim v cc m hnh WorkFlow Gii thiu cc cch hiu v workflow v cc m hnh th hin ca n. Qua , c th thy c nhng ch li khi kt hp workflow v mobile agent Chng 4: Xy dng ng dng Phn tch cc trng hp thc t xy ra, cc m hnh gii quyt cng cc chn la ti u cho h thng c xy dng, t a ra bn phn tch v thit k h thng Workag. Chng 5: Ci t v th nghim a ra hng dn ci t v s dng 3 module trong h thng ng thi a ra cc nhn xt, nh gi v h thng Chng 6: nh gi kt qu - Tng kt nhng kt qu t c v cha t c ca lun vn cng nh ca ng dng. Nu ra nhng hn ch ca chng trnh cng hng pht trin cho h thng v sau.


6

GVHD: GVC Cao ng Tn


Chng 1: Gii thiu tit vn :T khi B Quc Phng M to ra mng my tnh u tin-mng ARPANET nm 1967 cho n nay, vi s pht trin ca mng Internet, mng my tnh , ang v s pht trin v cng mnh m. Theo , cng vi s pht trin ca cc cng ty theo xu hng hin i ha, vi tnh ha dn n vic nhu cu thit k cc ng dng phn tn ngy cng cao. Hin nay, cc gii php mng nh client-server, peer-to-peer p ng hu ht nhng nhu cu ca cc cng ty. Tuy nhin m hnh client-server hoc peerto-peer li i hi s kt hp cht ch, tn ti song song ng thi gia cc my trong cng 1 h thng vi nhau. Trong 1 vi lnh vc, tnh ng b ny khng phi lc no cng c duy tr v ngi ta cn n 1 m hnh mi uyn chuyn hn, linh hot hn, c th hot ng ngay c trong tnh trng mt kt ni tm thi. V vy, mobile agent ra i. Li xt n mt vn khc trong bi cnh kinh t, cng ngh pht trin nhanh chng nh hin nay, l vic cc phn mm qun l truyn thng khng th p ng kp thi nhu cu thay i c cu lm vic, thay i quy trnh qun l ph hp vi mi trng lm vic cnh tranh, nng ng. p ng nhu cu th trng bin ng khng ngng, cc b my qun l phi lin tc thay i phng php, quy trnh lm vic sao cho chi ph tit kim c l ti a. Vi tc thay i , vic thc hin hay pht trin 1 phn mm mi ph hp vi quy trnh mi l khng th do vic xy dng phn mm qun l tn chi ph cao v thi gian di, c bit l nhng phn mm chuyn dng cho cc cng ty ln vi nhiu phng ban, nhiu quy trnh phc tp. C nhiu khi phn mm vit cha xong m quy trnh lm vic li thay i ri. Vi cch qun l cng vic bng workflow, mi vic tr nn d dng v linh hot hn nhiu. Mi khi quy trnh lm vic thay i, ch cn thay i, thit k li workflow, khng cn phi lp trnh li.


7

GVHD: GVC Cao ng Tn


T trc n gi, workflow c xy dng theo m hnh Client-Server, qun l tp trung chui cng vic, mi bin c xy ra u do server x l. u im ca m hnh ny l tnh ng b v thng nht cao. Tuy nhin, n cng c im yu v m hnh ny bt buc mi my tnh phi lin kt vi nhau, mi my ph thuc vo server. Khi server qun l workflow c s c th ton b h thng ngng hot ng. Trong thc t, c nhng h thng trong cc thnh vin c tnh c lp kh cao, khng bt buc s kt ni trong thi gian thc, chng c lp hoc cch xa nhau, nhng ni kt vi nhau thng qua mng my tnh. T xut hin nhu cu tho mn tnh bt ng b nhng vn duy tr s lin h gia cc bn di hnh thc workflow. V do , ti: ng dng th nghim Mobile Agent trong vic xy dng Workflow c thc hin.

Mc ch lun vnLun vn i su tm hiu v k thut mobile agent v cc dng thc, m hnh workflow t , xy dng mt ng dng th nghim xy dng v thc thi workflow bng k thut mobile agent. ng dng c chn y l xy dng h thng thit k v iu kin workflow nhm mc ch trao i, thc thi cc vn bn, ti liu trong t chc, on th hay doanh nghip. H thng ny s th hin r nt nhng u im ca workflow v mobile agent khi p dng vo vic gii quyt nhng yu cu t ra. H thng c xy dng da trn h nn (platform) Aglet ca IBM vi ngn ng Java, mt ngn ng ph bin vi tnh nng ni tri l chy c trn nhiu mi trng khc nhau, rt thch hp vi yu cu hot ng tt trong mi trng bt ng b ca lun vn.


8

GVHD: GVC Cao ng Tn


Chng 2: Khi nim v nguyn l hot ng ca Mobile AgentMobile agent l 1 loi software agent. hiu r v nn tng ca mobile agent, ta tm hiu khi qut v software agent

1. Tng qut v software agent1.1. Ngun gcTin hc ngy cng pht trin dn n vic hnh thnh nhu cu to ra nhng tiu chng trnh nh gn, thng minh, c kh nng hot ng 1 mnh v kt hp vi nhng tiu chng trnh khc Nm 1994, khi nim software agent c a ra bi Mark Sidell v Chuck Knuff v n nm 1995 th phin bn u tin ca agent xut hin. Nm 1975 k thut lp trnh ph bin l lp trnh c cu trc, n nm 1982, k thut lp trnh ph bin l phng php lp trnh hng i tng v n khi gent ra i to ra mt phng php lp trnh mi.


9

GVHD: GVC Cao ng Tn


1.2. Khi nimAgent i: l s kt hp ca nhiu k thut tin hc hin

Cc h thng phn tn

Phc hi thng tin AI & Khoa hc nhn dng

Mobile Code

AgentK thut c s d liu v c s tri thc

My hc

Hnh 1: Agent Phng php lp trnh mi

Khng c nh ngha chnh xc cho software agent, tuy nhin, ta c th tham kho nh ngha sau: Mt agent l mt thnh phn phn mm v/hoc phn cng m c kh nng hoat ng chnh xc hon thnh nhim v thay mt ch nhn ca agent. (Nwana,1996) Trn mng Internet, 1 agent ( c khi c gi l 1 intelligent agent ) l 1 chng trnh thu thp thng tin hoc thc thi 1 s dch v khc m khng cn ngi iu khin v hot ng theo thi gian c ln lch sn. 1 agent i khi c gi l 1 bot ( vit tt ca robot ) Mt v d v agent l chng trnh Infogate. Chng trnh ny c chc nng thu thp cc tin tc mi v lnh vc ngi dng quan tm v t ng gi thng bo n ngi dng khi c tin mi


10

GVHD: GVC Cao ng Tn


1.3. Cc tnh nng ca agent:1.3.1. Tnh t tr (autonomous):Agent c kh nng t kim sot nhng hot ng ca chnh n v lm vic, thi hnh cc tc v c lp vi ngi dng cng nh cc tc nhn khc. Ni mt cch n gin, nhng agent l nhng chng trnh c th t hot ng m khng cn c ngi dng thao tc. C nhiu hng nh gi v s t tr ca agent. Hai c tnh hng ch (goal-oriented) v tnh ch ng (pro-activeness) thng c dng nh gi mc t tr ca agent. Kh nng t tr ca agent ch yu c quyt nh bi tri thc trang b cho agent

1.3.2. Tnh thch nghi v t hc hi (adaptive/learning)Agent bit cch hc v t thay i cc hnh vi ca n theo cc kinh nghim thu c.

1.3.3. Bn vng trong qu trnh hot ng (persistent) 1.3.4. Hot ng hng ch (goal driven)Mi agent c to ra u c 1 mc ch v n hnh ng theo mc ch ny cho n khi mc ch c tha mn.

1.3.5. Giao tip v cng tc ( communicative/collaborative):Agent c kh nng lin lc, giao tip phi hp hot ng vi cc agent ca cng mi trg khc hay cc loi i tng khc trong cc loi mi trng khc

1.3.6. Linh hot (flexible)Agent c th hot ng trong nhiu mi trng, h iu hnh khc nhau


11

GVHD: GVC Cao ng Tn


1.3.7. Tnh di ng (mobility):L kh nng di chuyn t mi trng thi hnh ny sang mi trng khc ca mt agent. Kh nng di ng ca mt agent c phn thnh hai loi. Di ng mnh (strong mobility) l kh nng m h thng c th di chuyn c m chng trnh v trng thi thi hnh ca agent n mt mi trng khc. Di ng yu (weak mobility) l kh nng ca h thng ch c th di chuyn m chng trnh gia cc mi trng thi hnh vi nhau, m ngun c th mang km theo mt s d liu khi to nhng trng thi thi hnh th khng th di chuyn. Cc agent thng c kch thc nh, bn thn agent khng phi l mt ng dng hon chnh, khi hot ng trn 1 my, agent cn phi kt hp vi 1 chng trnh chy nn sn trn my m ta gi l AgentHost mi c th hot ng c. Ngoi ra c 1 s agent s kt hp vi 1 s chng trnh khc hot ng.

1.4. Phn loi agent1.4.1. Phn loi theo tnh nng 1.4.1.1. Agent tnh (Stationary agent) :c tnh: Ch lm vic trn 1 h thng, ni m agent bt u vng i. Nu stationary agent cn thng tin 1 h thng khc hoc mun tng tc vi agent nm h thng khc th chng phi s dng 1 trong cc c ch truyn thng khc nh RPC, RMI, DCOM

1.4.1.2. Mobile Agent:Khng l thuc vo h thng ni chng bt u lm vic C kh nng di chuyn t ni ny sang ni khc trong h thng mng my tnh ti nhng thi im v v tr do agent la chn


12

GVHD: GVC Cao ng Tn


Khi mobile agent di chuyn, n c th mang theo mnh trng thi v m chng trnh.

1.4.2. Phn loi theo mc ch:Intelligent Agents Collaborative Learning Agents

Cooperative

Adaptive

autonomous

Collaborative Agents

Interface Agents

Hnh 2: Phn loi agent theo mc ch

1.4.2.1. Collaborative agentsCollaborative agent l 1 chng trnh gip ngi dng gii quyt vn , c bit trong nhng trng hp phc tp hoc khng quen thuc, bng cch sa li, ngh nn lm g tip theo v ch n nhng vn cp thp. Mt collaborative agent c th c thm vo 1 giao din ngi dng c sn, v d nh cc chng trnh gi lp hoc tch hp vo thit k ca 1 dng c phn cng mi, v d nh gia dng.

1.4.2.2. Interface agents


13

GVHD: GVC Cao ng Tn


Interface agent l 1 chng trnh c th nh hng n giao din thao tc trc tip, nhng khng c s hng dn trc tip t ngi dng. Interface agent c cc d liu ngi dng nhp vo giao din v n c th to ra s thay i ti i tng ngi dng thy trn mn hnh, mc d c th l s thay i khng phi din ra ngay ng vi hnh ng ca ngi dng. Interface agent c th quan st nhiu tham s nhp vo ca ngi dng trong 1 khang thi gian no trc khi quyt nh thc hin 1 hnh ng.

1.4.2.3. Smart/Intelligent agentsC y c 3 mc ch: giao tc, t ng v d thch nghi v y chnh l tn gi khc ca software agent.

2. Mobile Agent v nguyn l hot ngNhng h thng phn tn truyn thng c xy dng trn nhng chng trnh tnh, chuyn d liu i v trn mng. Cn mobile agent (gi tt l MA) th ngc li.

2.1. Khi nim Mobile Agentnh ngha: Mobile agent l nhng thnh phn phn mm, bao gm m chng trnh, d liu v trng thi hot ng v c th t mnh di chuyn t ni ny sang ni khc Mobile agent chnh l 1 dng ca mobile code. (Mobile code l nhng chng trnh chuyn m n client v thc thi . V d cho mobile code: chng trnh appletc th gy nguy him cho my tnh do trong applet c th cha nhng on code ko ng tin cy, gy hi.) Mobile agent ngoi nhng tnh nng c bn ca mobile code cn c th : mang theo mnh d liu v trng thi thc thi, di tr trong mng di s kim sot ca chnh n. V vy, c th ni mobile agent an ton hn mobile code nhiu.


14

GVHD: GVC Cao ng Tn


2.2. Tnh cht mobile agent:C kh nng di tr t ni ny sang ni khc Lin lc c vi nhau, nhn bn, nhp li, tng hp tnh ton 1 s agent c kh nng cung cp dch v hoc interface cho cc ng dng k tha C kch thc nh C kh nng xc nh v dng nhng ti nguyn trn cc my tnh ang cha n.

2.3. Mt s h thng MA:2.3.1. AgletsAglets c xy dng v pht trin bi D. B. Lange v IBM Tokyo Research Laboratory. Xem thm phn 1.3

2.3.2. VoyagerVoyager l mt mi trng thng mi h tr pht trin cc ng dng agent c hng Object Space pht trin t gia nm 1996. Voyager tri qua nhiu ln nng cp v thay i t phin bn 1.0 cho n by gi l phin bn 4.5. Thng 03.2002 sn phm Voyager c nhng li cho Recursion Software, mt cng ty chuyn v cc sn phm vit trn C++ v Java m bo cho vic pht trin Voyager sau ny. Cc phin bn t 1.0 n 3.3 Voyager c phn phi cho cc nh pht trin nh mt freeware. Hin ti Voyager c phin bn 4.5 Evaluation hon ton tng thch vi JDK1.3, JDK1.2 v JDK1.1. Phin bn ny bao gm 6 sn phm, trong sn phm chnh yu dng cho cc ng dng mobile agent l Voyager ORB Professional. Voyager s dng ngn ng lp trnh Java vi c php chun to dng cc i tng xa mt cch rt d dng, cho php cc i tng ny trao i thng ip vi nhau, v di chuyn cc i tng gia cc my tnh c h tr mi


15

GVHD: GVC Cao ng Tn


trng Voyager. Voyager h tr mnh v tnh di ng vi kh nng mang ton b m chng trnh v d liu di chuyn t my o Java ny sang my o Java khc nu cc my o c h tr Voyager. Trng thi hot ng ca agent cng s c bo ton v tip tc thc thi ti ni agent n. Mt trong nhng c im ni tri khc ca Voyager l tnh ph qut. Cc chng trnh vit trong Voyager c th trao i thng tin hai chiu vi cc chng trnh vit bng SOAP, CORBA, RMI v DCOM. Cc dng thng tin c trao i c th l cc li gi hm t xa, cc dch v t tn, dch v th mc. Voyager c th c xem l mt ca ng, mt cu ni lm cho cc chng trnh theo chun khc tr nn lin thng vi nhau. Hn na, tt c cc chng trnh v i tng c th c t chc thnh mt khng gian chung, nh vy vic lin lc s tr thnh mtnhiu mt cch t ng. Phin bn 4.5 ca Voyager c b sung thm cc tnh nng rt quan trng h tr cho cc chun dch v Web. SOAP v WSDL cng c pht trin trong phin bn ny gip cho cc nh pht trin c kh nng trin khai cc ng dng truy cp ti cc dch v Web t xa v cc chng trnh Voyager c th truy cp nhau thng qua cc dch v Web. Th mnh tht s ca Voyager nm s n gin v d dng. S trong sut hay cch m Voyager che du cc k thut lp trnh phn tn phc tp lm cho vic xy dng cc ng dng mobile agent tr nn d dng hn rt nhiu. Vic tch hp cc cng ngh mi v cc chun mi vo cng mt sn phm to cho Voyager s hp dn rt ring bit.

2.3.3. MoleMole l h thng Mobile Agent c xy dng vi ngn ng Java ti i hc Stuttgart (CHLB c). Phin bn u tin (Release 1.0) hon thnh vo nm 1995, nm 1997 phin bn Release 2.0 c hon thnh, bn Release 3.0 c hon tt vo nm 1998 v n kt thc vi kt qu l mi trng n nh xy dng ng dng theo m hnh agent trn cc h phn tn. c xy


16

GVHD: GVC Cao ng Tn


dng trn Java, Mole c kh nng thc thi trn tt c cc mi trng c h tr JDK1.1.x (Jdk1.1.7 v Jdk1.1.8), s dng giao thc TCP/IP trong qu trnh giao tip. Mole h tr di chuyn yu- weak migration. thc hin giao tip gia cc agent Mole s dng cc c ch truyn thng ip, gi hm t xa RPCs, v c ch c trng ca Mole l session , badge. Ngn ng giao tip gia cc agent c Mole h tr l KQML. Vic trao i d liu gia cc agent c thc hin theo nghi thc TCP/IP. Mole cho php a tiu trnh/agent v qun l ti nguyn v lp lch cc tiu trnh trong h thng thng qua b lp lch trung tm MCP. Kh nng bo mt ca Mole c nh gi kh tt trong cc h thng agent. Mole tun theo m hnh bo mt sandbox ca java. Agent trong h thng Mole c chia lm hai loi: user agent v system agent. User agent l nhng agent di ng c kch hot bi ngi dng v khng th truy cp trc tip ti nguyn h thng. Ngc li, system agent (service agent) - c khi ng bi ngi qun tr - khng c tnh di ng v c php truy cp ti nguyn h thng. Mi trng Mole ph hp cho pht trin nhng ng dng trong cc lnh vc: Truyn thng, ng dng thuc lnh vc h thng thng tin in t. Mt s ng dng dc pht trin trn mi trng Mole: AIDA - Infrastructure for Mobile Agents, ASAP, ATOMAS, FESTIVAL (Mole office, Mole shopping), HAWK. Vi h thng m ngun m ca Mole, ta c th tin hnh ci tin, nng cp nhng chc nng hin c, v b sung nhng chc nng mi nh cc chc nng v cng c h tr lp trnh agent Mole tr thnh h thng agent hin i h tr tt cho vic pht trin cc ng dng da theo m hnh agent.

2.3.4. ZEUSZeus l mi trng do British Telecommunication pht trin h tr xy dng cc h thng a agents. Ngoi cc tnh nng thng thng trong vic to lp v qun l cc agent, Zeus c bit ch trng vic h tr mt phng


17

GVHD: GVC Cao ng Tn


php lun v mt b cng c mnh pht trin ng dng a agent trn mi trng phn tn. Zeus nh ngha mt phng php lun phn tch, thit k, trin khai h thng v cn km theo cc cng c cho php ngi pht trin c th bt li h thng cng nh phn tch s thc hin ca mnh. Hai giai on phn tch v thit k c miu t chi tit trong nhng cha c h tr bi cc cng c. Zeus Toolkit h tr hai giai on ci t v bo tr Zeus toolkit qua cc cng c Zeus Agent Generator v Zeus Agent Visualiser. Zeus cung cp nhiu Editor nh ngha agent v cc thuc tnh ca agent. Code Generator s t ng pht sinh m ngun cho agent t nhng thuc tnh c t. Hai c tnh quan trng ca cc Zeus agents l tnh t tr v cng tc. B phn Planner trong mi agent s h tr agent th hin tnh t tr. Kh nng thng lng v cng tc gia cc agent cng c Zeus tch hp vo trong toolkit thng qua mt th vin cc giao thc, cng cc chin lc thng lng v cng tc. Do c m ngun m, ngi dng c th thm vo th vin ny cc chin lc ring ph hp vi ng dng ca mnh. Cc Zeus agent truyn thng theo point-to-point socket TCP/IP vi mi message l mt chui cc k t m ASCII. Ngn ng trun thng Zeus s dng l FIPA ACL (http://www.fipa.org). Nhm cung cp kh nng hiu ln nhau cho cc agent, Zeus cung cp cc cng c cho vic nh ngha cc ontology-c s khi nim chung cho cng ng agent. Cc agent ca Zeus c phn tn qua mng v c th thc hin cc tc v ng thi. Chnh v th, vic qun l cc agent cng l mt vn m mi trng t ra. Visualiser ca Zeus cung cp cc cng c kim tra cc quan h giao tip gia cc agent, trng thi tc v nhng agent ang thc hin v trng thi bn trong ca agent. ng thi, Zeus Statistic Tool cho php ngi dng so snh cc thng k khc nhau v cng ng agent, chng hn nhng loi thng ip no agent gi v t l l bao nhiu, mt cch trc quan di nhng dng th khc nhau. Cng nhm qun l agent, Zeus cung cp nhng agent tin ch


18

GVHD: GVC Cao ng Tn


nh Agent Name Server hot ng nh mt Yellow Page, Facilitator nh mt White Page, Visualiser v Database Proxy. Mt hn ch ca Zeus l tuy c lit k vo mt trong nhng mi trng mobile agent nhng hin hng nghin cu v tnh di ng ca Zeus ch mi bc u, cha c ci t. Do m tnh bo mt ca Zeus cho cc agent hu nh khng c. iu ny c th s c khc phc trong cc phin bn sau. Zeus v ang c trin khai trong mt s ng dng nh Agent Based Work-flow Management, PTA: Personal Travel Assistance, Personal Computer Manufacture, Agent-based Electronic Commerce, Network Management (VPNP), Home Shopping.

2.4. Nguyn l hot ng2.4.1. So snh vi cc k thut khc hiu r v nguyn l hot ng trong mi trng mng ca Mobile Agent, ta s so snh n vi nguyn l hot ng ca cc k thut khc: C 3 cch thc thi code trong mi trng mng :

2.4.1.1. K thut pull codep dng trong m hnh client-server, bt u khi client gi yu cu n server, server s gi code v client v code thc thi, cho ra kt qu client. Thao tc gm 3 bc : Bc 1 : my client gi yu cu n server

request codecode

serverHnh 3: K thut Pull code Bc 1

client


19

GVHD: GVC Cao ng Tn


Bc 2 : server gi code cho client

request codecode code

serverHnh 4: K thut Pull code Bc 2 Bc 3 : code c thc thi client

client

code

execute

code

serverHnh 5: K thut Pull code Bc 3

client

V d : Cc Java applet c thc thi theo phng php ny Ch : trong m hnh ny, 1 bn sao ca code s c server gi ti client v thc thi client. Server vn lu tr code.

2.4.1.2. K thut push codeKhi c yu cu t ngi dng, 1 my (1 node) trong mng s gi code ti 1 my (1 node) khc trong cng mi trng mng v thc thi my . Thao tc ny gm 2 bc : Bc 1 : t bn thn my A gi code n my B m khng c yu cu t pha B. Trong m hnh ny, A ch l 1 my c ni mng vi B ch khng cn iu kin A phi l server


20

GVHD: GVC Cao ng Tn


code

remote execcode

node AHnh 6: K thut Push code Bc 1 Bc 2 : code c thc thi my B

node B

Code A

execute

code

node AHnh 7: K thut Push code Bc 2 Ch : A vn lu tr 1 bn sao ca code.

node B

Nh vy, trong 2 m hnh trn, ni gi code i vn gi li 1 bn sao ca code.

2.4.1.3. K thut autonomous codeCode t quyt nh s i v thc thi u Bc 1 : code sau khi thc thi my A s t ng gi v di tr ti mycode code

B

execute

migrate

node AHnh 8: K thut Autonomous code Bc 1

node B


21

GVHD: GVC Cao ng Tn


Bc 2 : code thc thi my B, lc ny code hon ton khng cn A na

execute

code

node AHnh 9: K thut Autonomous code Bc 2 V d : mobile agent hot ng theo phng php ny.

node B

T quyt nh ng gi, khng li bn sao v di tr n u l im khc bit ca mobile agent vi 2 k thut trn.


22

GVHD: GVC Cao ng Tn


2.4.2. i sng 1 agent :Creation

Serialize

MigrateHost

Deserialize

Execute Destroy or sleep Migrate Request Yu cu di tr t ngun Serialize

Migrate

Hnh 10: Vng i agent

Creation : Khi to agent, pht sinh ID cho agent, tu bin cu hnh cho agent Serialize: Lu li trng thi agent trc khi di tr n AgentOS khc Migrate: Di tr agent km tnh trng ca n n 1 ni khc Deserialize: Ti to li trng thi trc khi di tr ca agent Execute: Truy cp vo cc dch v ca host, lin lc vi cc agent khc, hon thnh nhim v ca agent Migrate Request: Yu cu c di tr n 1 host khc


23

GVHD: GVC Cao ng Tn


Destroy or sleep: Khi nhim v hon thnh hoc gp 1 tr ngi g khng th tip tc hot ng th agent s t hy hoc t a n vo trng thi ng ng (sleep) Mi agent u thc hin cc cng vic ca n tun t theo logic : u tin, agent c to ra, di tr t host ny sang host khc v cui cng b hu sau khi hon thnh nhim v. * Chi tit vng i agent Vng i agent bt u khi agent c to ra trn 1 host. Khi , agent s c cp 1 nh danh duy nht. Tnh trng ban u cng c th c khi to theo. Khi sn sng hoc nhn c lnh di tr n 1 host khc nm trong ng i ca agent, agent s lu li trng thi hin hnh ca mnh v tin hnh qu trnh di tr. Nu qu trnh di tr tht bi, agent s t ngng hot ng (deactivate) ri n s t kch hot li chnh mnh sau mt khang thi gian nh trc hay c kch hot v s tin hnh li qu trnh di tr n host khc. Khi di tr n host mi thnh cng, agent s phc hi li trng thi. Lc ny, agent bt u thc thi nhim v ca n, s dng cc dch v trn host, lin lc vi agent khc. Sau khi agent hon tt nhim v, n c th b hu hoc chuyn sang trng thi ng ng cho n khi c yu cu t b m trong chnh bn thn agent. Khi , agent s lu li trng thi ca n v di tr n 1 host khc.Vng i agent li lp li theo trnh t nh trn cho n khi n hon thnh nhim v hoc ht thi gian hot ng th agent s b hy.

2.4.3. Cc iu kin agent phi tha mnC 1 m xc nhn duy nht Xc nh c nhng agent khc ang thc thi trong cng host C kh nng nhn v gi thng ip cho nhng agent khc


24

GVHD: GVC Cao ng Tn


2.5. Agent Host :2.5.1. Khi nimAgent khng th tn ti mt mnh m n phi da trn mt phn mm khc c gi l host hay AgentOS sng v hot ng. Chnh host s to ra agent t an code c, thc thi agent, chuyn n n host khc hay hy i agent. Khi host b hy th agent ang hot ng da trn host cng b hy theo

2.5.2. Cc yu cu cho AgentOS :c lp flatform : AgentOS phi c kh nng h tr agent trong mi trng mng khng ng nht. Multithreaded: AgentOS phi c kh nng cho php nhiu agent hot ng ng thi ( c th c u tin khc nhau) Di tr c agent v trng thi ca n : Agent c th yu cu host di tr agent ti host khc v thc thi. C c ch cho cc agent trong host giao tip c: AgentOS phi cung cp kh nng lin lc thng qua s kin gia cc agent trong cng 1 node cng nh gia cc agent cc node khc nhau. Ti s dng agent: AgentOS phi cung cp cho ngi dng kh nng phn loi, lu tr agent c th ly ra s dng li v sau. Bo mt: AgentOS phi c c ch chng li nhng agent c to ra vi xu nhm ngn chn vic b nh cp thng tin hoc b tn cng t chi dch v. C th m rng c


25

GVHD: GVC Cao ng Tn


2.6. ch li ca mobile agent2.6.1. Gim bandwidthK thut mobile agent cho php ngi dng ng gi thng tin, gi n n my ch v thc hin x l d liu, trao i cc b ti . Nh vy s gp phn lm gim d liu th trn mng, gp phn lm gim ti mng ng k. Phng chm thc hin ca k thut mobile agent l : mang x l n ni cha d liu hn l mang d liu v ni x l.

2.6.2. Gim trVic iu khin cc h thng quy m ln s phi chp nhn mt s tr mng nht nh. Nhng iu khng c php xy ra trong cc h thng thi gian thc nh iu khin n giao thng, dy chuyn sn xut.... Khi , gii php mobile agent rt hu ch trong vic khc phc tr nh vo vic agent c th c gi i t trung tm iu khin v hnh ng cc b, t tr, trc tip thi hnh cc ch dn ca ngi iu khin.

2.6.3. C th thc thi khi ngt kt ni mngKhi gp s c mng v khng th di chuyn tip, agent s t a mnh vo trng thi ch cho n khi mng c thit lp li th agent s khi ng li v di chuyn tip hon thnh nhim v c giao.

2.6.4. Thc thi bt ng b v t ngThng thng, cc thit b di ng thng ph thuc vo cc kt ni mng t tin nhng rt yu t. V th, nhng tc v cn c kt ni lin tc gia thit b di ng v mng c th s khng c tnh kinh t hoc khng kh thi v mt k thut. Gii php mobile agent gii quyt vn ny bng cch nhng nhng tc v cn thc hin vo mobile agent ri gi ln mng. Sau khi c gi i, agent tr nn c lp thi hnh khng ng b v c kh nng t tr. Cc thit b di ng sau c th kt ni li n agent tr v.


26

GVHD: GVC Cao ng Tn


2.6.5. Nhanh v gim thiu liVi kh nng phn ng nng ng vi cc s kin v nhng thay i bt li, mobile agent gip vic xy dng h thng mnh m v chu li cao c d dng hn.

2.6.6. Khc phc tnh trng khng ng nhtVic x l tnh ton trn mng c bn l khng ng nht v s a dng v phn cng v phn mm c s dng. Do mobile agent c lp vi my tnh ( c lp vi phn cng v h iu hnh ) v tng vn chuyn, n ch ph thuc vo mi trng thi hnh nn mobile agent cung cp mt iu kin ti u cho vic lin kt cc h thng khng lin quan li vi nhau.

2.6.7. ng gi cc giao thcKhi d liu c trao i trong h thng phn tn, vic truyn v nhn d liu phi c m ha bng cc giao thc cn thit. Cc giao thc ny c s ha bi mi my trong h thng. Tuy nhin, 1 khi cc giao thc phi tin ha ph hp vi nhng yu cu mi v s bo mt hoc tnh hiu qu, chng tr nn cng knh, nng n v tr thnh vn nan gii. Vi gii php mobile agent, cc agent c th mang trn mnh cc giao thc thch hp v di chuyn ti cc my xa thit lp cc knh truyn nhn thng tin tng ng.

2.7. Mi trng ng dng mobile agentMobile agent hch hp vi nhng loi ng dng sau:

2.7.1. Thu thp d liu phn tn:Trong trng hp c nhu cu truy vn phc tp, chuyn bit v lin quan n nhiu ngun d liu khng ng nht, vic c cc mobile agent n cc ngun tin v khai thc ti ch, ri quay v vi nhng thng tin cn thit s lm gim ti mng v gii quyt tt bi tan tng thch.


27

GVHD: GVC Cao ng Tn


2.7.2. Theo di v thng bo tin cp nhtng dng c in ny lm ni bt bn cht khng ng b ca cc mobile agent. Cc agent c th c gi i, n ni c ngun tin v hot ng theo di ngun tin ngay c khi ngi dng ngt kt ni. Sau , khi ngun tin c s thay i , agent s quay v bo cho ch nhn. Cc agent c th c gi i ch mt dng thng tin no xut hin, ri sau bo cho ngi dng bit hoc t n c nhng hnh ng thch hp i vi thng tin .

2.7.3. Gim st v phn tn thng tinCc mobile agent l minh ha cho m hnh Internet Push, cc agent c th ph bin tin tc v cp nht phn mm cho cc nh sn xut. Cc agent mang cc software component v cc th tc cn thit n cc my c nhn ca khch hng v t cp nht phn mm trn my . M hnh ny gip nh sn xut ch ng hn trong vic phc v khch hng m bo dch v ca mnh. Mt khc, cc ng dng lai ny cng t ra hiu qu i vi cc mng cc b hay cc chng trnh qun l quy trnh t ng, sn xut gip ngi qun tr gim st cc h thng con.

2.7.4. X l song songDo cc agent c th to ra cc bn sao ca n trn mng, to ra 1 ng dng y tim nng ca agent l qun tr cc tc v song song.Mt ng dng i hi nhiu ti nguyn b x l c th c phn b cho cc agent mang i thc hin trn nhiu my tnh khc nhau tn dng cc ti nguyn trng v cn bng ti.

2.7.5. Thng mi in tCc ng dng thng mi in t cho php ngi dng thc hin cc giao dch trong kinh doanh trn mng. Mt giao dch c th bao gm s thng lng vi cc thc th xa v c th i hi truy cp ngun thng tin lin tc thay i. T thc t ny sinh nhu cu thay i hnh vi ca cc thc th t


28

GVHD: GVC Cao ng Tn


c mt nghi thc chung trong vic thng lng. Hn na, vic di chuyn cc thnh phn ca ng dng tin gn n ngun thng tin thch hp cho giao dch cng c quan tm. V th cng ngh mobile agents l mt gii php rt hp dn cho lnh vc ny.

2.7.6. Qun tr h thng mngi vi nhng h thng mng ln, vic chn on li, duy tr s n nh ca h thng l cc cng vic rt kh khn. Vic ng dng mobile agent vo vic qun tr mng s gip cho cc cng vic chn on li v duy tr t xa s n nh ca h thng c d dng hn

2.7.7. H tr cc thit b di ngDo c im ti nguyn hn ch v khng kt ni thng xuyn, vic xy dng cc ng dng da trn mobile agent vi kh nng di chuyn n cc my tnh c cu hnh mnh hn hot ng (truy vn c s d liu, tm tin) ri tr kt qu v s l mt gii php tt cho ngi dng cc thit b di ng.

2.8. Bo mt m bo agent ng tin cy, AgentOS s tin hnh 1 s kim tra vi agent Authentication: kim tra xut x agent Vertification: kim tra m agent Authorisation: cho php agent c quyn nhn v truy cp 1 s ti nguyn. Trn qu trnh di tr ca agent, m bo thng tin c bo v, c th p dng phng php m ho PKI.


29

GVHD: GVC Cao ng Tn


3. Tng qut v AgletAglets c xy dng v pht trin bi D. B. Lange v IBM Tokyo Research Laboratory. Hin nay, b Aglets Software Development Kit (ASDK) do IBM pht trin dng li phin bn 1.1 Beta3 trn nn JDK1.1. Phin bn mi nht ca ASDK l 2.0.2 do SourceForge pht trin trn nn JDK1.3.

3.1. Khi nimAglet l nhng i tng Java c th di chuyn t host ny sang host khc trn mi trng mng. Khi 1 aglet di chuyn, n mang theo mnh c m chng trnh ln d liu. Trong m hnh i tng aglets, mt mobile agent l mt i tng di ng c lung kim sot ring ca n, lm vic theo s kin v lin lc vi cc agent khc bng cch truyn thng ip. Aglets c mt c ch nh danh duy nht v ton cc da trn URL. Aglets h tr c ch di ng yu (weak- mobility). Cc aglets giao tip vi nhau mt cch ng nht, v c lp vi v tr lu tr thng qua i tng proxy. Sut chu k sng, cc aglets sn sng bt nhng s kin (clone, mobility, persistence) pht sinh trong mi trng c phn ng thch hp. Agent c th giao tip ng b hoc khng ng b thng qua cc loi thng ip: synchronous, one-way, hay future reply. Aglets s dng ATP (Agent Transfer Protocol) cho vic di chuyn v giao tip. Aglets s dng 2 loi mu thit k chnh l ch-t (Master-Slave) v hnh trnh (Itinerary) cho vic di chuyn ca cc agent. Aglets l mt trong nhng platform c s dng nhiu nht pht trin cc h thng mobile agent. Mt s n thc hin vi Aglet c th k n l TabiCan (http://www.tabican.ne.jp) - ch in t chuyn bn v my bay v tour du lch trn gi -, Cps720 (Artificial Intelligence Topics with Agent) ti i hc Ryerson University, M , Acme H thng h tr Sales Order Processing trong vic mua bn chng khon, ca i hc Loughborough, Anh.


30

GVHD: GVC Cao ng Tn


Aglets l mt h thng Java mobile agent h tr cc khi nim thi hnh t tr v nh tuyn ng trn l trnh ca n. C th xem aglets nh l mt khi qut ha v m rng ca applet v servlet. Aglet server l chng trnh cung cp mt mi trng thi hnh v mt my o Java cho aglet hot ng. Ngoi ra, Aglet server cng s dng mt trnh qun l tip nhn v kim sot aglet mt cch an ton.

3.2. Tnh chtMt chng trnh aglet c nhng tnh cht sau y: L mt i tng kh chuyn. N l mt i tng ng dng vi cc phng thc v d liu trng thi, v kh nng di chuyn, n c th gi i nhng aglets hoc t chuyn n mt a im khc trong mng nh mt thc th c lp. Tnh t tr. Mt aglet c kh nng t quyt nh xem s lm g hoc s di chuyn v u v khi no. Kh nng tng tc vi nhng i tng khc. N c kh nng tng tc vi nhng aglets khc hoc nhng i tng stationary. Khi cn thit, n s t gi n hoc cc aglets khc n mt a im xa tng tc vi cc i tng . Khng kt ni. Nu mt my tnh ang ngt kt ni vi 1 mng, aglet vn c th t ng ch v s di chuyn khi my tnh ny kt ni li. X l song song. Nhiu aglets c th di chuyn v thc thi c lp trong cng mt h thng.

3.3. Cch ci t v s dng Aglet trn mi trng WindowTh hin ca Aglet trn mi trng Window chnh l server Tahiti. Trong file nn aglets-2.0.2.jar bao gm ASDK( Aglets Source Development Kit) v mi trng thc thi ng dng ( run-time environment). Phn chnh trong gi l Aglets library, phn ny cho php nhng ngi vit phn mm c th dch


31

GVHD: GVC Cao ng Tn


v chy nhng ng dng Aglets, phn cn li l nhng agents c bin dch trc v nhng chng trnh dng thc thi aglets platform. thc thi Aglets platform bn cn phi ci ti thiu l Java 2 Run-time Enviroment (JRE), tuy nhin bn nn ci t y Java 2 Source Development Kit (J2SDK) bin dch cc agents, tham kho trang ch ca SUN: http://java.sun.com. Aglets c th c ci t trn mt my chy UNIX/LINUX, Microsoft Windows hoc Mac OS X. Ni chung, mi kin trc my tnh c th chy c Java 2 Platform u c th ci t v thc thi c Aglets. Qu trnh ci t c thc hin trn nn Window ( cc bc ci t ging nh trong Windows i vi cc h iu hnh khc). Mc nh l bn ci t v c th thc thi mi lnh Java. C 3 cch ci t aglet, y chng ta ch tm hiu 1 cch ci t l ci t t gi c bin dch sn: y l cch c khuyn nn s dng bi v gi c bin dch sn bao gm nhng thnh phn mi nht ca Platform v th vin ASDK. Nu bn khng phi l mt ngui vit ng dng bn nn dng cch ny ci t. C platform v th vin ASDK c t trong mt file jar m bn download v. Tn ca file jar ny cho bit version Aglets m bn ang s dng. Version ca file jar c cp n trong ti liu ny l 2.0.2 ng vi tp tin aglets-2.0.2.jar Nhng bc chi tit sau y s hng dn cch ci t Aglets t file jar ni trn.

3.3.1. Gii nn file jarBi v aglets c nn trong mt file jar nn vic u tin bn phi gii nn n. Hy ch l khi gii nn th cc tp tin c gii nn s nm trong th mc hin hnh, do tt hn ht l bn nn to mt th mc ring ca bn dng s dng trong qu trnh ci t Aglets, v d l E:\MAgent. Khi bn to


32

GVHD: GVC Cao ng Tn


xong th mc, bn copy file jar ni trn vo th mc v nh lnh sau y trong console: jar xvf aglets-2.0.2.jar Trong sut qu trnh ci t bn s thy nhng dng sau y xut hin trn mn hnh, nhng dng ny s lit k nhng tp tin ang c gii nn:

Hnh 11: Gii nn aglets-2.0.2.jar


33

GVHD: GVC Cao ng Tn


Nu cc bc ci t thnh cng bn s thy cc th mc con bn trong th mc ci dt ca bn, cc th mc con bao gm: bin: s cha nhng chng trnh thc thi c cho Aglets 2 platform, ngoi ra n cn cha nhng file cn thit dng cho cc bcci t tip theo. cnf: cha nhng file cu hnh cho Aglets platform public: cha vi v d agent mu , v y l th mc root cho cc ng dng agent sau ny ca bn. lib: y l th mc th vin ca Aglets 2 library( bao gm nhng tp tin jar) v vi tp tin th vin cn thit khc i vi Aglets. Nu c th, bn hy c tp tin README v INSTALL bao gm trong gi ci t v ty thuc vo version m bn download.

3.3.2. Ci t platform ci t platform, bn cn phi chy Apache Ant, tool ny dng chy v bin dch nhng ng dng java. Aglets 2 c ng gi chung vi mt version ca Ant ci t platform, ngai ra bn c th s dng bt k version no mi hn 1.5 cng c. ci t Aglets vi Ant, bn cn phi vo th mc bin trn v nh lnh ant.bat nh sau:


34

GVHD: GVC Cao ng Tn


Hnh 12: Ci t platform

Trong qu trnh dch v ci t th vin, bn s thy nhng message thng bo v version ca Aglets.

3.3.3. Ci t chnh sch bo mtNh nhng chng trnh Java khc, Aglets platform cn nhng quyn trong chnh sch bo mt ca java thc thi cc tc v nh m socket, chy cc ng dng agent khc, m tp tin trong my client, Bn c th copy cc


35

GVHD: GVC Cao ng Tn


tp tin bin/.aglets.policy hoc chng trnh Ant c th lm iu ny gip bn. Ngoi ra Ant s ci t keystore cho bn. Aglets cn mt keystore cha nhng kha bo mt dng khi di tr; thng thng cc keystore c lu trong file /.keystore. ci t cc chnh sch bo mt v keystore nh trn trong th mc home, bn chy file install-home:

Hnh 13: Ci t chnh sch bo mt

3.3.4. Khai bo cc bin mi trng Aglets platform c th hot ng c, bn cn phi khai bo cc bin mi trng sau y bao gm AGLETS_HOME v AGLETS_PATH. Ngoi ra, chy Aglets platform mt cch tin li hn, bn phi khai bo th mc bin ca aglets vo bin mi trng PATH. Bn nh cc lnh sau y trong console ca windows: set AGLETS_HOME=E:\Magent set AGLETS_PATH=%AGLETS_HOME% set PATH=%PATH%;\%AGLETS_HOME%\bin hoc c th khai bo cc bin mi trng trn trong control panel.


36

GVHD: GVC Cao ng Tn


3.3.5. Chy Aglets serverSau khi ci t Aglets platform v keystore, bn c th chy c Aglets server, tn gi l Tahiti. Tahiti c th chy bng cch chuyn vo th mc \bin v nh dng lnh agletsd.

Hnh 14: ng nhp server Tahiti Tahiti s yu cu ngi dng ng nhp, ngi dng s phi in username v password. Nu bn ci t keystore thnh cng th bn cso th ng nhp vi username l anonymous v password l aglets. Sau khi ng nhp thnh cng th ca s chnh ca server Tahiti s hin ra. Bn trong mn hnh chnh ny, ngi dng c th qun l server, to v hu cc agents,


37

GVHD: GVC Cao ng Tn


Hnh 15: Mn hnh Server Tahiti

ng server, bn c th click vo button close hoc chn Exit trong Aglet menu. Trong c hai cch Aglets s hi bn c chc s thot hay khng, khi bn click OK thot, Cancel s ng ca s li v Reboot s lm server restart

3.4. Aglet LifeCycleLp ibm.com.aglet.Aglet cung cp cc chc nng c bn cho 1 i tng mobile v mi aglet phi l th hin hc subclass ca n. dng 1 aglet, trc ht ta phi instantiated (to ra th hin) ca n. C 2 cch lm iu ny. Cch 1: to 1 aglet hon tan mi t nh ngha lp bng cch gi hm AgletContext.createAglet(URL codebase, String name, Object init). Hm ny to ra 1 th hin mi trong context v khi ng n nu cn thit. Cch 2: to ra 1 bn sao ca 1 aglet tn ti bng cch dng hm Aglet.clone(). Aglet c sao ra s c cng trng thi nh aglet gc nhng c AgletID khc.


38

GVHD: GVC Cao ng Tn


Context A CloneProxy Aglet

Context B Dispatch RetractProxy Aglet

Dispose

CreateClass

DeactivateB lu tr th cp

Activate

Hnh 16: Vng i Aglet Khi c to ra, 1 i tng aglet c th c gi i n v/hoc nhn v t 1 server khc, ngng hot ng v c lu tr 1 ni no ri li c ti kch hot. 1 aglet c th t gi chnh n n 1 server khch bng cch gi hm nguyn gc Aglet.dispatch (URL dest). chnh xc hn, aglet c ng trong 1 aglet context v c th di chuyn t context ny n context khc trong sut qu trnh hot ng. Bi v server c th phc v nhiu context trong cng 1 my o Java (JVM), v 1 host c th phc v nhiu server nn context c t tn vi nhng thc tnh sau: a ch ca host, thng l a ch IP Port m server dng nghe S context trong server. V d: atp://aglets.ibm.com:1434/context_name Khi di tr, 1 aglet phi ngng hot ng, ln lt a trng thi hot ng v bytecode ca n vo 1 form chun v ri c chuyn n ch. Bn pha nhn, i tng Java c ti xy dng da theo d liu nhn c t gc v 1 thread c ng k v thc thi. Aglets c th bn vng. Do 1 mobile aglet cn c phn mnh thnh bit-stream, mi mobile aglet c th bn vng trong t nhin. Hm


39

GVHD: GVC Cao ng Tn


Aglet.deactivete(long timeout) gip 1 aglet c lu tr li trong b nh v a aglet vo trng thi ng ng trong 1 khang thi gian nht nh. Sau khi ht thi gian hoc khi 1 chng trnh khc yu cu n ti kch hot, aglet s c ti kch hot trong cng context m n b nhng hot ng. Khng ging nh cc i tng Java thng thng s b t ng hy bi ch thu thp rc ca Java ( garbage collector ), 1 i tng aglet s t quyt nh c hy chnh n hay khng. Nu bn gi phng thc dipose() hy 1 aglet, hm onDisposing() c gi hon tt cng vic ty vo trng thi hin hnh ca aglet. Tuy nhin, khi aglet b hy, nhng ti nguyn ang c s dng nh c s d liu hay file s khng c t ng hy nh aglet, bn phi c nhng lnh ring hy chng.

3.5. Aglet APIAglet

Aglet Proxy

Message

Aglet Proxy

Aglet

Aglet Context Hnh 17: Aglet API Aglet API l b th vin bao gm cc hm chuyn bit dnh cho vic pht trin agent. Nh vo Aglet API, kh nng ni ting ca Java l vit mt ln, thi hnh bt c u c vit li l vit mt ln, lu hnh bt c u. Mt khi aglets c to ra, n s chy trn mi my c h tr Aglet API m khng quan tm n ngun gc h iu hnh v phn cng bn di hay ngun gc c th ca Aglet API c ci trn my ang chy. Aglet : chnh l lp o com.ibm.aglet.Aglet : nh ngha cc phng thc nn tng kim sat s di chuyn v vng i ca mobile agent. Mi mobile agent u phi k tha t lp o ny. Vi hm quan trng ca lp ny l :


40

GVHD: GVC Cao ng Tn


Aglet.dispatch(URL) : di chuyn aglet t my n ang c tr n my ch theo thng s nhp vo. Aglet.deactivate(long time) : lu tr aglet v a aglet vo trng thi ng ng. Aglet.clone() : sinh ra 1 th hin ca aglet mi c cng trng thi nh aglet gc nhng l i tng kiu AgletProxy ch khng phi kiu Aglet. Aglet Proxy : com.ibm.aglet.AgletProxy: l 1 lp interface hot ng nh 1 i din ca aglet v cung cp cch chung nht truy cp aglet ng sau n. Lp aglet c nhiu phng thc public m 1 vi trong s ny l ra khng c gi trc tip t cc aglet khc v l do bo mt. V vy mi aglet nu mun lin lc vi nhng aglet khc th u tin l phi to ra i tng proxy v giao tip thng qua interface ny. Ni cch khc, aglet proxy hot ng nh 1 i tng che chn, bo v agent khi cc agent nguy him. Khi c gi, aglet proxy s truy cp n SecurityManager xc nh xem i tng gi c c quyn thc thi phng thc hay khng. Mt chc nng quan trng khc ca aglet proxy l cung cp location transparency. Nu 1 aglet thc s ang c tr 1 host khc, aglet proxy s chuyn tip yu cu n host v tr v kt qu cho host cc b hin ti. Message : com.ibm.aglet.Message : i tng aglet giao tip bng cch trao i nhng i tng thuc lp Message. Mt i tng Message c 1 i tng kiu String xc nh kiu ca thng ip. Mt thng ip c th c gi n aglet bng cch gi hm AgletProxy.sendMessage(Message msg) Aglet Context : com.ibm.aglet.AgletContext : cung cp interface cho mi trng runtime chy aglet. Mi aglet u cha 1 tham chiu n i tng AgletContext hin hnh ca n thng qua hm Aglet.getAgletContext(), v dng n cha thng tin nh a ch ca host, bng lit k Aglet Proxy hoc to 1


41

GVHD: GVC Cao ng Tn


aglet mi. Khi di tr n host mi, i tng context s b hy i v thay th n l i tng aglet ca host mi khi agent di tr n.


42

GVHD: GVC Cao ng Tn


Chng 3: Khi nim v cc m hnh WorkFlowCng vic qun l workflow xut pht t nhng cng vic i hi tnh t ng trong nhng vn phng doanh nghip, trong mi ti liu cn phi c s ha v c lu chuyn gia cc nhm lm vic. Ngy nay, cng vic qun l workflow thu ht rt nhiu nhng quan tm da vo kh nng ca n trong m hnh ha, thc thi v qun l tin trnh. Tin trnh cng vic khng ch l tin trnh trong kinh doanh m cn l bt k mt tin trnh no cn c iu khin v qun l. Nhng im chnh ca vic qun l workflow l nhng ha hn trong s dng n qun l tin trnh kinh doanh Workflow gip nh qun tr ln k hoch, qun l 1 cch t ng cc nhim v, gim st tnh trng cng vic, a thng tin n tng thnh vin ng lc, c c ci nhn tng quan v tin trin cng vic. C 2 cch hiu v workflow. Cch 1: workflow theo ngha rng, l 1 m hnh nghip v, trong cc cng vic c phn cng r rng, thc hin theo th t t sn. Khi nim workflow theo cch hiu ny c t lu v c ng dng rng ri trong cc ngnh cng nghip. Cch 2: Khi nim workflow trong khoa hc my tnh ng dng vo qun l tin trnh kinh doanh (tm hiu di y). Khi nim v workflow ni chung rt phc tp v a dng, trong phm vi lun vn ny, xin c trnh by v khi nim workflow trong qun l tin trnh kinh doanh.


43

GVHD: GVC Cao ng Tn


1. Khi nimWorkflow l qu trnh in ton ho hay t ng ha mt phn hoc ton b mt tin trnh kinh doanh. ngha ca workflow khi ny n gin ch l cc lung cng vic. H thng qun tr lung cng vic: qun l v thc thi cc m hnh lung cng vic thng qua vic thc thi cc phn mm. Gm 2 thnh t: B phn h tr c t m hnh lung cng vic B phn vn hnh m hnh c t

2. ch li p dng workflow:Li ch ca vic s dng worflow trong qun l tin trnh kinh doanh c lit k nh sau: Tin trnh kinh doanh c vch ra r rng, v th trch nhim v nhng mi quan h cng tc c nh r. D dng ti u ha cng vic kinh doanh v nhng nh ngha chnh xc trn. Tin trnh kinh doanh c chia nh thnh nhng module v nhng module ny c th t chc li theo m hnh workflow thch ng vi tin trnh kinh doanh chung, v th d dng thch nghi nhanh chng vi nhng thay i khng on trc c trong nhng yu cu v iu kin kinh doanh. Workflow c th theo di hng ngy. Workflow tch hp vi nhng ng dng hay nhng h thng khc vo tin trnh kinh doanh. Workflow phn nh r quan h v trch nhim trong cng vic do n to ra nhng phn cng vic ring. Theo d on, workflow s to nn nhng phng php, nhng k thut t nhiu ngun trong khoa hc my tnh cng nh qun tr hc. V d, k thut workflow lin quan n qun tr c s d liu, tnh ton client-server, giao din


44

GVHD: GVC Cao ng Tn


ngi dng, ng dng v kt hp cc h thng ph, qun l ti liu, gi lp, ti cu trc v thc tp kinh doanh

3. Cc dng workflowC rt nhiu dng workflow t n gin n nng cao. gc th nghim ca lun vn, ng dng s ch p dng cc dng workflow n gin.

3.1. Cc dng n gin:3.1.1. Tun t (Sequence):M t: mt hot ng trong lung cng vic c kch hot ngay sau khi 1 hot ng khc kt thc trong cng 1 tin trnh. V d: hnh vi gi ha n c thc hin ngay sau hnh vi gi hng ha Ci t: dng tun t c s dng m hnh cc bc lin tip trong cng 1 tin trnh ca lung cng vic. M hnh:Cng vic A Cng vic B

Hnh 18: M hnh Workflow Tun t Ch thch: Cng vic B c thc hin sau khi cng vic A c hon thnh.

3.1.2. Phn lung song song (Parallel Split)M t: 1 im trong 1 tin trnh ca lung cng vic l ni 1 cng vic c tch thnh nhiu cng vic con. Cc cng vic con c th c tin hnh ng thi cng lc vi nhau (song song nhau). V d: Sau khi hnh vi nhn tin hon thnh, hnh vi gi hng v hnh vi xut ha n s c kch hot v tin hnh ng thi M hnh:


45

GVHD: GVC Cao ng Tn


Cng vic B Cng vic A Cng vic C

Hnh 19: M hnh Workflow song song

3.1.3. ng b hoM t: 1 im trong lung cng vic l ni cc tin trnh hay cc cng vic con nhp li lm 1 tin trnh hay cng vic n. Trong dng m hnh ny, tt c cc lung i vo phi ch nhau ti im ng b ha. V d: Sau khi hnh vi gi hng v xut ha n c thc hin, hnh vi lu tr mi c kch hot. M hnh:Cng vic A

AND Cng vic B

Cng vic C

Hnh 20: M hnh workflow ng b ha Ch thch: A v B phi hon thnh th C mi c kch hot

3.1.4. Php chn loi tr (Exclusive Choice)M t: ti 1 im trong lung cng vic s din ra s la chn cng vic no s c kch hot tip theo trong 1 lot cc cng vic k tip V d: Sau khi cng vic kim th phn mm c thc hin, da vo kt qu kim th s quyt nh cng vic tip theo l lp trnh hay ng gi phn mm.


46

GVHD: GVC Cao ng Tn


M hnh:Cng vic B

Cng vic A

La chn B hay C

Cng vic C

Hnh 21: M hnh workflow Chn lai tr Ch thch: Ch c hoc B hoc C c thc hin, khng th tin hnh ng thi c hai.

3.1.5. Trn n gin (Simple Merge)M t: 1 im trong lung cng vic l ni 2 hay nhiu nhnh gp nhau, khng c s ng b ha gia cc nhnh. V d: Cng vic lu tr c thc hin sau khi cng vic gi ha n hoc cng vic nhn ha n c thc hin. M hnh:Cng vic A

Cng vic C Cng vic B

Hnh 22: M hnh workflow Trn n gin Ch thch: ch cn 1 trong 2 cng vic A hoc B c hon thnh th cng vic C s c kch hot


47

GVHD: GVC Cao ng Tn


3.2. Cc dng nng cao:3.2.1. Chn a nhnh (Multi-Choice)M t: Mt im trong tin trnh l ni m mt hoc nhiu nhnh c chn theo mt quyt nh hoc da trn d liu ca nghip v.Mu ny khc vi mu 2.4.1.4 (chn loi tr) c th chn mt hoc nhiu nhnh c chn ra v thc thi, tng t nh php XOR. Cc v d:Sau khi thc hin hnh vi nh-gi-thit-hi, hnh vi lin h phng cu ha hoc hnh vi lin h cng ty bo him c thc hin. t nht mt trong hai hnh vi ny c thc hin. Tuy nhin, cng c th l c hai cn c thc hin. M hnh:

Hnh 23: M hnh workflow Chn a nhnh

3.2.2. Trn ng b hoM t: Mt im trong tin trnh l ni nhiu nhnh hi t li thnh mt tin trnh duy nht. Nu c nhiu hn mt nhnh thc thi, vic ng b ha (vic i nhau gia cc nhnh ) c thc hin. Nu ch c mt nhnh c thc thi, cc nhnh khc c th hi t m khng cn ng b ha. Trong mu ny nu c mt nhnh c kch hot, th n khng th kch hot li ln na trong khi cn ang i cc nhnh khc hon tt. Mu ny khc vi mu ng b ha ch n ng b da trn s nhnh thc s c kch hot lc thc thi. Cn mu ng b ha bt buc tt c cc nhnh i ra khi nt AND phn lung (AND-Split) phi u c thc hin.


48

GVHD: GVC Cao ng Tn


Cc v d: M rng v d trong mu 6 (chn a nhnh), sau khi mt hoc c hai hnh vi lin-h-phng-cha-chy v lin-h-cng-ty-bo-him hon tt (da trn vic n c c thc thi hay khng), hnh vi trnh-bo-co phi c thc hin (ch duy nht mt hnh vi) M hnh: Cng vic A Cng vic C Cng vic B Hnh 24: M hnh workflow Trn ng b ha

3.2.3. Trn a nhnhM t: Mt im trong tin trnh l ni hai hoc nhiu nhnh hi t li v khng c ng b ha. Nu nhiu hn mt nhnh c kch hot, ngay lp tc hnh vi sau im trn s bt u i vi mi kch hot ca mi nhnh vo. Mu ny chnh l th hin cho c ch trn phc v cho mc ch dng chung cho cc thnh phn trong quy trnh. Cc v d: Thnh thong hai hay nhiu nhnh c cng im kt thc. Thay v lp li tin trnh ny cho mi nhnh (c th phc tp), ta dng mu trn a nhnh. V d n gin ca trng hp ny l 2 hnh vi kim tra n xin vic v x l n xin vic cng thc hin song song v thc hin trc hnh vi ng trng hp. M hnh: Cng vic A Cng vic C Cng vic B Hnh 25: M hnh workflow Trn a nhnh


49

GVHD: GVC Cao ng Tn


3.2.4. DiscriminatorM t: Mu Discriminator l mt im trong tin trnh lm nhim v i n khi mt trong cc nhnh hon tt sau mi kch hot cc hnh ng tip theo. T tr i, n vn cho php cc nhnh vo cn li hon tt nhng pht l chng. Trong trng hp tt c cc nhnh hon tt, n tr v tnh trng ban u c th c kch hot li ln na. Cc v d: lm tng tc phn hi, hai yu cu tm kim c gi n 2 c s d liu trn Internet. Kt qu no n trc s tip tc lung cng vic. Ci cn li s khng c quan tm. M hnh: Cng vic A Cng vic C Cng vic B Hnh 26: M hnh workflow Discrimator

3.2.5. Cc vng lp tu M t:Mt im trong tin trnh l ni cc hnh vi c thc hin lp li nhiu ln. Mu ny l th hin cho c ch lp cu trc. Trong mu ny vic lp thng c quyt nh bi cc iu kin hoc la chn. Cc v d:Tin trnh xem xt sn phm : trong tin trnh ny vng lp cc hot ng Make,Read, Note, Approve l mt vng lp cu trc. M hnh:

Hnh 27: M hnh workflow Cc vng lp ty


50

GVHD: GVC Cao ng Tn


3.2.6. Kt thc khng tng minhM t: Mt tin trnh phi c chm dt khi khng cn g thc hin tip. Ni cch khc, khng cn hnh vi no ang thc hin trong workflow v khng c hnh vi no s c kch hot (tuy nhin workflow khng trong tnh trng deadlock). Mu ny thng c th hin trong cc ngn ng m hnh ha khng bt buc iu kin : mi tin trnh hoc tin trnh con phi c nt quy nh cui cng trong m hnh. Mu ny gi l kt thc khng tng minh, bi v rng buc kt thc ca n khng bt buc tin trnh cng vic phi thc hin n im cui, m ch da trn s cng vic cn c kh nng c thc hin. Cc v d: Trong mt cng vic c nhiu hot ng thc hin, gi s ang thc hin n mt cng vic k cui. Nu ta p dng mu 2.4.2.14 (Withdraw) th trong tin trnh ang lm s khng cn hot ng no phi lm tip. Khi tin trnh cng vic s kt thc m khng cn phi i phi thc hin hot ng cui cng ( b hy)

3.2.7. a th hin khng ng bM t: Mu ny m t mt hnh vi c th c nhiu th hin. Nu hnh vi c th kch hot cc th hin ca n, th mi th hin ca hnh vi ny s to mt tin trnh (mt th hin lung) ring bit c iu khin c lp vi cc th hin lung khc pht sinh t hnh vi ny. Hn na, khng cn thit phi ng b cc th hin lung ny. Cc v d: Mt khch hng ang t mt cun sch t quy sch in t nh Amazon c th t mua cc quyn sch khc cng mt thi im. Rt nhiu hnh vi (v d: lp ha n, cp nht thng tin khch hng, ) c thc hin khi khch hng t hng. Tuy nhin, cn phi c nhiu th hin iu khin cc hot ng thuc v mt c nhn t hng (v d nh cp nht hng d tr, giao hng). Mu ny c th dng trong trng hp cc hot ng t hng khng cn phi ng b.


51

GVHD: GVC Cao ng Tn


3.2.8. a th hin vi thng tin bit trc thi im thit kM t: Trong mt th hin ca tin trnh, hnh vi c th c kch hot nhiu ln. S cc th hin ca mt hnh vi trong mt tin trnh cho trc bit c thi im thit k. Khi cc th hin hon tt th hnh vi khc mi c bt u. V d: Vic cp giy php i vi cc cht liu nguy him yu cu phi c 3 loi giy php khc nhau. iu ny c ngha l hot ng cp giy php c xc nh s ln thc hin trc l 3 ln ( thi im thit k).

3.2.9. a th hin vi thng tin bit trc thi im thc thiM t: L trng hp mt hnh vi c kch hot nhiu ln. S cc th hin ca mt hnh vi c th bin i, tuy nhin s c xc nh thi im thc hin, trc khi cc th hin ca hnh vi c to ra. Mt khi tt c th hin hon tt, hnh vi khc s c bt u. V d: trong vic kim tra tin thc hin phn mm, s ln kim tra ph thuc vo phc tp ca tng n c th, ngun nhn lc, mc ri ro. Hot ng kim tra hon ton khng th xc nh lc thit k quy trnh phn mm, m ch c quyt nh vic kim tra bao nhiu ln khi vo giai on trin khai quy trnh nghip v cho mt phn mm xc nh.

3.2.10. a th hin khng bit trc thng tinM t: Dng cho trng hp hnh vi c kch hot nhiu ln. S th hin ca hnh vi cho trc khng bit c trong thi im thit k v trong thi im thc thi - trc khi cc th hin c to ra. Cc th hin ca hnh vi c th c to ra mt cch ty . Mt khi tt c cc th hin hon tt, hnh vi k tip mi c bt u. S khc bit ca mu ny so vi mu 14 l khi c mt vi th hin c thc thi hoc hon tt, nhng th hin mi vn c th c to ra.


52

GVHD: GVC Cao ng Tn


Cc v d: x l mt trng hp bo him, c th c hoc khng c nhiu bn tng trnh ca cc nhn chng c x l. S lng bn tng trnh l c th thay i. Thm ch khi ang x l cc bn tng trnh, nhn chng mi li xut hin v s bn tng trnh li tng ln. Nh vy vic x l cc bn tng trnh l khng th bit trc c s ln thc hin d mc thit k (m hnh ha) hay thc thi. Ch khi trin khai nghip v, bao gi khng cn cng vic x l bn tng trnh no th hot ng x l tng trnh mi kt thc.

3.2.11. Chn la b tr honM t: Mt im trong tin trnh l ni mt trong s cc nhnh c chn. Khng ging nh tch XOR, nhnh c chn khng c thc hin ngay (da trn d liu hoc quyt nh) m c nhiu nhnh tng t c to ra. Tuy nhin, ch c mt nhnh c thc thi. Khi mi trng thc hin kch hot mt nhnh, cc nhnh khc s b hy. Vic chn nhnh b hon cho n khi vic x l mt trong cc nhnh tng t thc s bt u. l thi im hy cc nhnh cn li. Mu ny tng t nh Discriminator, tuy nhin c 2 im khc bit: Discriminator dng trong c ch trn. Discriminator vn cho php thc hin cc cng vic ca nhng nhnh cn li, nhng vic thc hin cc nhnh ny s khng dn n kch hot hot ng k tip. V d: Cc chuyn cng tc cn c ph chun trc khi thc hin. C hai cch ph chun mt nhim v : hoc l trng phng ph chun nhim v (hnh vi A) hoc c qun l d n (hnh vi B) ph chun nhim v. Hai hnh vi ny c thc thi duy nht ch mt, v vic chn la gia A v B l khng tng minh, ngha l cng mt thi im cc hnh vi A v B c gi n trng phng v qun l d n. Ti thi im m mt trong hai hnh vi ny c chn la hon tt, hnh vi cn li s bin mt.


53

GVHD: GVC Cao ng Tn


3.2.12. ng vo song songM t: Mt tp cc hnh vi c thc hin theo th t ty sau : i vi mi hnh vi trong tp, vic thc thi c xc nh vo thi im chy, v khng c hnh vi no c thc hin cng lc (c ngha l khng c 2 hnh vi no c thc hin trong cng mt th hin ca workflow cng mt thi im). Cc v d:Hi qun i hi cc ng vin phi thc hin 2 cuc kim tra: kim tra th cht v kim tra tinh thn. Cc cuc kim tra c th din ra vi bt k th t no min l khng c 2 cuc kim tra no cng thi im. - Vo cui mi nm, ngn hng thc hin 2 hot ng cng li tc v tnh tin vay trn mi ti khon.Cc hot ng c th thc hin vi bt k th t no.Nhng v chng c th c thc hin trn cng mt ti khon, nn khng c thc hin ng thi.

3.2.13. Ct mcM t: Vic kch hot mt hnh vi da vo mt trng thi c th no , v d nh hnh vi c kch hot ch khi i n mt ct mc cn hot ng. Xem xt cc hnh vi A, B v C. Hnh vi A ch c kch hot khi hnh vi B thc thi cn C th cha, ngha l A s khng c kch hot trc khi B thc thi hoc sau khi C thc thi. Hnh 17 minh ho trng hp ny. Trng thi gia B v C c m hnh bng im m. im ny l ct mc cho A. Cc v d: Trong mt cng ty du lch, cc chuyn bay, xe cho thu, v cc khch sn c th c t trc min l ha n cha in ra. Khch hng c th hy n mua hng trc 2 ngy khi c k hoch phn phi. Khch hng c th i hi cc chng nhn bay su thng sau chuyn bay M hnh:


54

GVHD: GVC Cao ng Tn


Hnh 28: M hnh workflow Ct mc

3.2.14. WidthdrawM t: Mu ny th hin vic mt hot ng i kch hot b loi khi danh sch hot ng. Cc v d: Mt bn thit k phn mm c kim tra bi nhiu nhm k s vi cc hot ng kim tra khc nhau. Tuy nhin, nhiu khi c kt qu ng hn, ch cn mt hot ng kim tra c thc hin. Khi , thi im c nhiu hot ng kim tra ang sn sng thc hin, cho php hy mt s th hin kim tra hin ti (ang trong trng thi sn sng hot ng) kp tin hot ng.

3.2.15. Hy trng hpM t: Mt th hin ca nhnh hot ng b loi b hon ton k c cc hot ng c thc hin nhiu ln trn cc nhnh . Cc v d: Trong qu trnh thu ngi lm, cc ng vin t rt n ca mnh th cc th hin hot ng cho vic xt ng vin hin ti s c hy. Cc th hin hot ng ca vic xt ng vin thng t trn mt nhnh lung cng vic. Khi tt c cc hot ng ng vi nhnh xt cho ng vin ny c hy.


55

GVHD: GVC Cao ng Tn


4. Kt hp k thut MA v workflow4.1. ch liu im ca MA: c th hot ng trong khi ngt mng, kh nng t tr cao, t x l cc vn xy ra trn ng di chuyn, hot ng tt trong mi trng mng bt ng b, uyn chuyn, linh hot. u im workflow: gip ngi qun tr tit kim thi gian v cng sc qun l quy trnh nghip v, d dng thay i c cu qun l trn my tnh khi c s thay i trong thc t. T trc n nay, cc phn mm qun l workflow vn hot ng theo m hnh C-S. Khuyt im ca m hnh l: Khi c s c mng xy ra, mi cng vic s b ngng li Ngi qun tr h thng workflow phi gii quyt tt c cc li xy ra nh thay i ng i hoc hy cng vic khi 1 client c s c. Thay m hnh C-S bng m hnh Mobile Agent, s gii quyt c nhng khuyt im trn. Ngoi ra, cn c thm nhng u im khc nh: chng trnh agent s t c thc ngi thc hin cng vic hon thnh cng vic ng thi hn, gim lu lng ng truyn do khng phi lin lc vi server trong khi hot ng....

4.2. Cc hng nghin cu tch hp h thng mobile agent v workflow4.2.1. Agent Enhanced Workflow:Vi m hnh tch hp ny, 1 engine workflow s lm trung tm iu khin mi hot ng, cn agent s hot ng nh nhng service c cung cp bi h thng qun l workflow. Workflow engine s qun l vic khi to v hy ca agent, do , trong m hnh ny, agent ch yu l cc interface agent, khng cn phi l 1 agent thng minh. Thc t, trong nhng phn mm c


56

GVHD: GVC Cao ng Tn


thng mi da trn m hnh ny nh IBM MQSeries Workflow, InConcert, chc nng ca agent ch nh mt phn ca phn mm bnh thng.

4.2.2. Agent Based Workflowy l 1 h thng phn tn vi nhiu agent. Cc agent ny hon tan c lp vi nhau, mi agent c mt cng vic ring v tn ti cho n khi n thc thi xong phn vic ca n. Trong m hnh ny, tin trnh kinh doanh c th hin trn h thng mng theo m hnh mobile agent. Cc cng vic s c giao cho agent v agent s di tr trn mng theo workflow nh sn hon thnh cng vic. M hnh ny rt st vi thc t, i hi agent phi thng minh, c kh nng lin lc v giao tip vi cc agent khc hon thnh cng vic. Hin nay, vn cha c phn mm no da trn m hnh ny c thng mi ha. Tuy nhin, ang c kh nhiu nghin cu v m hnh ny nh ADEPT (Jennings et al, 1996) hay FireFlow System (Yan, 1999) Lun vn s tin hnh xy dng ng dng h thng workflow s dng mobile agent theo m hnh Agent Based Workflow, c th ng dng s l xy dng v iu kin workflow nhm mc ch trao i, thc thi cc vn bn, ti liu trong doanh nghip.


57

GVHD: GVC Cao ng Tn


Chng 4: Xy dng ng dng1. Gii thiu ng dngng dng s l xy dng v iu kin workflow nhm mc ch trao i, thc thi cc vn bn, ti liu trong cng ty. ng dng s l 1 h thng khp kn t khu thit k, chnh sa workflow cho n iu khin thc thi MA theo workflow thit k. H thng c t tn l Workag.

1.1. C cu t chc trong c quan:Cng ty

Phng 1

Phng 2

Phng 3

....... .......

.......

T 1

T 2

.......Role 2

Role 1

.......

Nhn vin 1

Nhn vin 2

.......

Hnh 29: C cu t chc trong c quan Trong doanh nghip, b my lm vic vn hnh lin tc v hiu qu, tn ti nhu cu rt ln i hi s lin lc, trao i gia cc phng ban vi nhau


58

GVHD: GVC Cao ng Tn


bng nhng bo co, ti liu theo nhng quy trnh c th. Do cc quy trnh trao i ny thng xuyn thay i theo nhng tnh trng v yu cu khc nhau ca doanh nghip nn khng th xy dng phn mm theo kiu truyn thng tha mn nhu cu ny. Trong khi , s dng cng ngh workflow li rt thch hp. iu kin thc t trong doanh nghip nh sau: ng u Cng ty l Gim c. ng u mi phng l trng phng ng u mi t l t trng Di t trng c th c cc role nh t ph, thnh vin... Mi nhn vin trong cng 1 phng c 1 my tnh ni mng LAN, c IP khc nhau v duy nht, c ci AgentOS. Cc phng ban khc nhau c th thuc nhng mng LAN khc nhau, nm nhng quc gia khc nhau nhng u nm trong 1 mng WAN chung ca cng ty. Xy dng workflow theo cc cp trong cng ty, ti mi node, s quy nh r chc nng tng node 1 v d cho m hnh workflow: quy trnh kim li phn mm: sau khi lp trnh, module s c chuyn t phng Coding n phng Testing. Phng Testing s khng chia thnh cc t m ch gm trng phng v cc thnh vin. Workflow cp phng s l:

Phng Coding

Phng Testing

NX: D phng Coding v phng Testing nm trong cng 1 mng LAN ca cng ty hay nm 2 nc khc nhau th h thng vn hot ng tt. M hnh workflow cp role cho phng Testing: gi s phng Testing c 3 nhn vin v 1 trng phng, module s c tch ra thnh 3 phn mi nhn vin kim tra. Sau khi kim tra, kt qu s c gi li cho trng phng


59

GVHD: GVC Cao ng Tn


u vo

u ra

Nhn vin 1

Trng phng

Nhn vin 2

Nhn vin 3

Hnh 30: V d 1 workflow n gin

1.2. Cc cch gii quyt vn :1.2.1. S dng nhn cng thc hin chui cng vic trong cng ty m khng cn nh n h thng my tnh h tr, cn c cc nhn vin chuyn vic a cc mu bo co nh gi n tng phng, giao cho tng nhn vin sau i thu thp li, tng hp kt qu v em kt qu qua phng ban khc giao cho cc nhn vin khc tip tc cng vic. u im: khng tn chi ph xy dng h thng h tr Khuyt im: Tn thi gian nhn vin giao mu bo co n cc nhn vin khc v tn thi gian thu thp, tng hp li bo co. D ln ln gia cc cng vn, bo co vi nhau do s lng bo co nhiu. Cc nhn vin gp kh khn trong vic xem, tham kho nhng bo co ca cc nhn vin khc d c php. Kh khn trong vic chnh sa nu bo co thc hin sai Quy trnh cng nhc, khng linh hot


60

GVHD: GVC Cao ng Tn


1.2.2. S dng m hnh Client-ServerServer lu tr cc mu bo co, cc client s truy cp vo server ly bo co v my mnh lm. Khi thc hin xong, client s gi tr kt qu v server client khc tip tc ti v my thc hin. u im: mi thao tc u do server qun l nn qun l c tp trung. Khuyt im: Lng gi tin di chuyn trn mng l rt nhiu s gy thiu bng thng Nu mu bo co c thc hin client c li th server s phi gi tr li client, gy tn thi gian l lng ph ng truyn. Nu client b s c mng th s khng thc hin cng vic c.

1.2.3. S dng Mobile AgentMobile agent s mang cc mu bo co theo mnh n cc my. Khi nhn vin hon thnh bo co, agent s kim li, nu bo co khng hon chnh, agent s yu cu nhn vin thc hin li bo co. Nu bo co hon thnh, agent s ng gi chnh n v di tr n 1 my khc tip tc cng vic. Khi hon thnh, agent s tng hp kt qu v gi v cho my ch. u im: Gim lu lng thng tin di chuyn trn mng C th hot ng ngay c khi mng gp s c nn c bit thch hp vi cc mi trng mng bt ng b. C tnh ch ng cao, c th kim li ngay ti my nhn vin gip tit kim thi gian v chi ph di chuyn. V nhng l do trn nn mobile agent c la chn gii quyt yu cu t ra


61

GVHD: GVC Cao ng Tn


1.3. Yu cu c bn ca h thng:Thit k c 1 workflow hon chnh. M hnh workflow phi cha c nhng cu trc sau: Tch 1 cng vic ra nhiu cng vic nh, thc hin tun t hoc song song. Hp cc vic nh li theo cc m hnh trnh by phn B.II.5 ng vi mi node trn workflow, cho php thit k 1 form bo co ring Xy dng framework cho h thng Workflow trn nn mobile agent ng dng trong trng hp c th: nh ngha h thng workflow cho vn ly thng tin, nh gi thng tin t cc chuyn gia Yu cu k thut: Trin khai c trn mi trng mng LAN Thc thi c trn nhiu h iu hnh. S lng node trong workflow khng gii hn.

1.4. Cc i tng s dng h thng:Administrator (ngi qun tr h thng): cn c kin thc tt v mng v my tnh User (ngi dng thng thng, tng ng vi cc nhn vin trong cng ty): ch cn bit nhng kin thc c bn v mng nh kt ni, nhn tin v kin thc v x l vn bn

1.5. Cu trc h thngH thng gm 3 phn chnh:

1.5.1. Workflow Document Designer:Cho php administrator thit k cc mu bo co dnh cho user. Chng trnh ny s dng k thut dragndrop thit k da trn cc i tng ha


62

GVHD: GVC Cao ng Tn


c sn. Chng trnh s chuyn cc i tng v b tr ca chng thnh file vn bn XML v cc file ny s c nh km vo tng node trn workflow c mang i bi mobile agent.

1.5.2. Workflow Designer:Chng trnh cho php administrator thit k workflow vi cc dng workflow c sn bng cch ko th. Chng trnh c xy dng trn nn graphic, cho php ngi dng chn i tng v ko qua phn thit k, nh km cc vn bn cn thit vo tng node trn ng i . Cc i tng c trong chng trnh gm: Node: 1 node trong workflow l i din cho 1 my tnh trong mng. Khi chn node, ngi dng phi nhp y thng tin cho node nh IP ca node, tn node. ng i: th hin dng 1 mi tn, th hin cng vic i t node ny sang node khc Trm trung chuyn: c nhiu loi trm trung chuyn, th hin cc dng khc nhau ca workflow V d:OR : La chn gia 2 node mng

1.5.3. Agent Manager:Hot ng da trn nn tng Aglets ca IBM, to mi v qun l cc agent. Ngi dng cn a vo cc thng tin nh : WF cn thc hin, thi gian sng ca agent. H thng s sinh ra cc loi agent sau: Wfagent( Workflow Agent) : agent mang cc mu vn bn n cc ngi dng trong workflow thit k. Wfagent s chuyn thng tin nh dng XML thnh cc i tng ha gip ngi dng d thao tc. Sau khi cc ngi dng cung cp y thng tin cho agent, agent s chuyn cc i tng ha v li dng


63

GVHD: GVC Cao ng Tn


vn bn XML, tng hp li i tip n node khc theo workflow nh v gi kt qu v cho Agent manager. Uagent (Updater agent): Khi c thay i ng thng tin sa li t Agent Manager, AM s gi uagent mang cc thng tin mi cn sa i n cc agent ang chy trn h thng v cp nht thng tin mi cho cc agent ny. Nu uagent gp 1 uagent khc c thi gian cp nht mi hn hoc gp agent tip xc vi uagent mi hn th n s t hu. Nagent (Notifier agent): c mi khi wfagent tip xc vi 1 ngi dng mi, n s gi thng tin cp nht v cho Agent Manager thng qua nagent.

1.6. Kin trc h thng:Ngi dng A Agent Hostwfagent nagent

Ngi dng B Agent Hostwfagent

Agent Hostwfagent nagent

CSDL WF wfagent uagent CSDL DOC ( XML)

Workflow Designer

Agent Manager

Workflow Document Designer

CSDL LT (XML)

Hnh 31: Kin trc h thng


64

GVHD: GVC Cao ng Tn


: ng di tr ca MA : truy cp c s d liu wfagent: Workflow agent uagent: Updater agent nagent: Notifier agent CSDL WF: Lu tr cc workflow c thit k trc. CSDL DOC: Lu tr cc mu bo co c thit k trc CSDL LT: Lu tr cc mu bo co c wfagent mang v Mi ngi dng cn ci sn trn my chng trnh Agent Host l Server Tahiti, chng trnh ny gip cc agent n my c th hot ng c. Quy trnh hot ng nh sau: S dng chng trnh Form Designerthit k ra cc mu bo co, chng trnh Workflow Designer s dng cc mu bo co ny, thit k workflow. Agent Manager sau khi load workflow s to ra wfagent. Wfagent da trn workflow c cung cp s ln lt hoc to cc bn sao i n cc my v yu cu user trn mi my t

Documents

7064558-ng-dng-Th-Nghim-Mobile-Agent-vao-xay-dng-Workflow