1. Mobile Agents Technology - Programming with Aglet
Felix T-L Lin
KE TA
IEEM, NTHU
2018/11/20

2. Reference
D. B. Lange and M. Oshima, Programming and Deploying Java Mobile Agents with Aglets, Addison-Wesley, 1998
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3. Introduction – 1/2 Software agents Features
A software agent is one kind of computer software that executes a specific task
Features
Autonomous, goal-oriented, collaborative, flexible, adaptive, and mobile characteristics (Maamar, 2002)
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4. Introduction – 2/2 Mobile agents
It can be defined as a software agent that is able to migrate autonomously from one host to another in a computer network (Papaioannou and Edwards, 1999)
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5. Mobility – 1/3 Mobility is a special ability of a mobile agent
It means the agent is movable. It has the unique ability to transport itself from one system to another in a network
Divide agents into 2 types (based on mobility)
Stationary agent vs. mobile agent
RPC vs. remote programming
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6. Mobility – 2/3 Remote Procedure Call Stationary agent
It always operates in a specific host
It often involves multiple interactions to accomplish a given task
Increase the network traffic
The operation style is called Remote Procedure Call, RPC model(Dalmeijer, Hammer, and Aerts, 2000)
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7. Mobility – 3/3 Remote programming Mobile agent
It allows you to dispatch it to a remote host
The interactions can take place locally
Systems can be improved by reducing the flow of row data
The operation style is called Remote Programming model (Walter, Rudigr, and Hartmut, 1998 )
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8. Aglet
Concept of Aglet
Originated at IBM’s research laboratory in Japan
A small application program or applet with the capability to serve as a mobile agent of services in a computer network
Java objects can move from one host on the network to another
Users can receive, manage and send aglets from Tahiti aglet server
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9. Tahiti Server
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10. Agent Transfer Network Sender Receiver Suspend Execution
Serialize Agent
Encode Agent
Transfer Agent
Receiver
Resume Execution
Deserialize Agent
Decode Agent
Receive Agent
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11. Aglet Life-Cycle Model – 1/43
Context A
Context B
Dispatch
Aglet
Aglet
Dispose 4
Clone 2 6
Retract 5
Create
Deactivate
Activate 1
Class
File
Disk
Storage
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12. Aglet Life-Cycle Model – 2/4
Ex1: Aglet creation
public class CreationExample extends Aglet {
public void run() {
try {
getAgletContext().createAglet(
getCodeBase(), “CreationChild”, null );
} catch (Exceptioin e) {
System.out.println(e.getMessage()); }
Public class CreationChild extends Aglet {
public CreateChild() { … }
public void onCreation(Object init) { … }
public void run() { … } }
createAglet()
Aglet()
onCreation()
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run()

13. Aglet Life-Cycle Model – 3/4
Ex2: Aglet dispatch
run()
Original
host
dispatch()
onDispatching()
onArrival()
Destination
host
run()
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14. Aglet Life-Cycle Model – 4/4
public class DispatchingExample extends Aglet {
boolean theRemote = false;
public void onCreation(object init) {
addMobilityListener(
new MobilityAdapter() {
public void onDispatching(MobilityEvent e) {
//…… }
public void onArrival(MobilityEvent e) {
theRemote = true; );
public void run() {
if(!theRemote) {
try {
URL destination = new URL(
(String)getAgletContext().
getProperty(“location”) );
dispatch( destination );
} catch (Exception e) {
System.out.println(e.getMessage()); }
else {
// The remote aglet runs here
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15. Aglet Event Model CloneListener Aglet MobilityListener
Clone Events
CloneListener
Mobility Events
Aglet
MobilityListener
Persistence Events
PersistencyListener
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16. Aglet Communication Model
Message
Message
Aglet/Application
Proxy
Aglet
Reply
Reply
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17. Agent Transfer Protocol, ATP
It is a simple application-level protocol modeled on HTTP. ATP is designed to transmit an agent of the agent system
An ATP request consists
a request line
headers fields
contents
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18. Application – 1/5 Background
A well-designed matching model can reduce the trading time and improve its efficiency
A complex model for SIP trading
The concept of matching model
for SIP trading
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19. Application – 2/5
Scenario
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20. Application – 3/5
it is assumed that you setup m indices and membership functions for evaluating partners. Now, you want to evaluate the j th trading partner. The performance value of the j th trading partner can be defined as a formula
means the i th index value of the j th trading object
means the weight of the i th index
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means the membership function of the i th index

21. Application – 4/5 The collaboration of agents and the matching process
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22. Application – 5/5 Scenario assumption Buyers Sellers
Felix,
Trappey,
Umc,
Sellers
Dora,
Joanne,
Paul,
The product is IEEE 1394a Device Controller
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23. ASDK Installation Copy the ASDK source to a folder
Setup the environment variables
Add aglet_home (d:\Aglet1.1_\aglets1.1.0)
Add jdk_home (d:\Aglet1.1_\jdk1.1.8)
Set classpath (d:\Aglet1.1_\aglets1.1.0\lib;d:\Aglet1.1_\aglets1.1.0\public;)
Set path (d:\Aglet1.1_\aglets1.1.0\bin;)
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24. Demonstration
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25. Demonstration Scenario assumption Buyers Sellers Broker, 140.114.53.57
Felix,
Trappey,
Umc,
Sellers
Dora,
Joanne,
Paul,
Broker,
The product is IEEE 1394a Device Controller
2018/11/20