Mobile agents applications

Introduction

Mobile

agents

1

--Internet-based electronic commerce of today

app Icatlons has not made shopping that much easier for the consumer" In fact, it has maybe even made it Rosane Maria Martins worse" We have more information about Magali Ribeiro Chaves products than ever, more stores to visit" The

..difference between the electronic marketplace

Lucz Pzrmez and and the real-world marketplace is that you visit Luiz Fernando Rust da Costa Carmo the store electronically instead of physically"

So, finding and combining the relevant

information/service is becoming a critical task" ,_I

There is a need for facilities that perform these ~

..~~ integrating tasks and thus overcome problems I

" " " " " such as distribution and heterogeneity. These ~~~ Rosane Mana Martlns, Magali Ribeiro Chaves, ~ "1J.acl 1 es are o en re erre "t1" ft fi

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m ormat1on sources are use, nel er oes e know how they are used" The user is provided

m'mI!t=- with the vision that only one information source

Mobile agents, Distributed applications, E-commerce exists"

To address this problem, several exciting new

.i'rnffiT8- technologies have been developed. Several

groups of artificial intelligence (AI) researchers Automatlc, autonomous browslng has an Increaslngly 1

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are a rea y act1ve y mvo ve m trymg to eslgn important task in information discovery and assisted

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networ an e V1rtua purc ases. recursive growth of the network has made this process

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ac mte Igent asslstant IS compose y increasingly time consuming and less rewarding. Presents

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two posslble solutlons to thls problem: Data Agents and,

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artl "ficla " 1mte " 11Igence"

(DAI)

CollaborAgents which were developed with IBM s Aglet

concepts"

Workbench -a particular Implementatlon of mobile agents.

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.lS concerne Wl a orms o socla

Aiso surveys the agent technology and dlscusses the agent " " "

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.." aCt1V1ty m systems compose o m t1p e

bulldlng package used to develop both mentloned "

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appllcatlons" Condudes that the future of local Interactlon, 1988) An .& f...

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" d I" ..lmportant J.orm o mteract1on m suc

re uce networ oa Ing, server exl Ilty an app Icatlon " " " "

..systems IS co-operat1ve problem solV1ng WhlCh

autonomy whlch are supported by mobile agent technology, ,

." ...occurs when a group of logically decentralized

ali help to provlde a levei aglllty above dlstrlbuted problem "

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.agents choose to work together to achleve a

sovlng.

common goal.

-~~ The "agent" term is widely used in different

-~I"-I.'IIII-, areas, such as distributed systems or software

The research register for this journal is available at engineering, and for this reason, there are many http:llwww"mcbup.com/research-registers definitions for it" However, agent systems The current issue and full text archive of this journal is present key characteristics that differentiate

available at them from other software.

http:llwww.emerald-library"com/ft Agents are autonomous, persistent (software) components that perceive, reason,

communicate and act in someone's favour Intemet Research: Electronic Netwo,king Applications and Policy " " " " " " , Volume II. Number 1.2001 .pp. 49-54 mfluencmg ltS enV1ronment" ThlS envlronment

Mobile agents applications c Intemet Research: Electronic Networking Applications and Policy 'c' RO5ane Maria Martin5 et al..'c Volume 11 .Number 1 .2001 .49-54

interaction is the multiagent systems' principal another server, spawn new agents, and interact

element. with other agents. On completion, the mobile

This paper contributes two applications that agent delivers the results to the sending client or emphasize the mobile agent technology as a to another server.

significant and revolutionary paradigm for In order for these agents to exist within a distributed problem solving: Data Agents and system, or to themselves form a system, they CollaborAgents. Both were implemented using require a framework for implementation and IBM's mobile agent framework known as Aglets execution. This is known as the agent Software Development Kit (ASDK). environment.

Data Agents is a mobile and intelligent

multiagent auxiliary prototype for the retrieval Aglets technology: a Java-based execution of distributed structured information in a environrnent

scenario of several "online" bookstores. The Developed by the IBM Japan research group, proposed system is based on a group of agents this package is a framework for programming trying, simultaneously, to find products ofusers' mobile network agents in Java. We can use a interest in several virtua1 places known by them, few expressions to describe an aglet (IBM Japan presenting the resu1ts in a homogeneous way. Research Group, 1998): written in pure Java,

CollaborAgents is a prototype where users light-weight object migration, built with create autonomous agents to buy and sell goods persistent suppon, event-driven. It is easy to in a context of the automobile components understand why Java is necessary for W AN distribution problem. A car assembler looks for application's existence in today's heterogeneous suitable supplies to attend the subsidiaries' ne tw or king enV1ronmen . t.esl B .des proV1 .d . mg

orders. This commercial transaction is done I .& .

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p auorm m epen ence, ava a so prOVl es

through the Internet. ..

sandbox secunty to protect the host agamst

This paper is organized as follows. .ma An I ..lClOUS attac kS from a len app lCat1Ons.I . I ..

overview of agent concept and detatled

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n 1 e an app et s s ort an ._{k 1 '} h d bonng .. peno d Of

descnpt1ons of a mobtle agent enV1ronment ..

kn A 1 W kB h .. th execut1On, an aglet can eX1st and execute tasks

own as 9 ets or enc are glven m e. .

.

Th th . d . d .b th forever. One ofthe mam dlfferences between an

next sect1on. e lr sectlon escn es e

...aglet and the simple mobile code of Java

overall architecture of two appltcat1ons: Data

A d C II b A Th fi I .applets, is the itinerary that is carried along with

gents an o a or gents. e ma sect1on

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d futu

k the aglet. By having a traveI plan, aglets are

en presents e conc USlOn an re wor .

capable of roaming the Internet collecting information from many places. The itinerary

.can change dynamically giving the aglet the

Mobile agents .

sense of self-governmg and the look of an Mobile agents are processes dispatched from a intelligent agent (that of course is in the hands source computer to acçomplish a specified task of the programmer).

(Chess et al. , 1993; General Magic Inc., 1998) .An aglet can be dispatched to any remote host Each mobile agent is a computation along its that supports the Java virtual machine. This own data and execution state. In this way, the requires from the remote host to have

mobile agent paradigm extends the RCP preinstalled Tahiti, a tiny aglet server program communication mechanism according to which implemented in Java and provided by the aglet a message sent by a client is just a procedure framework. A running Tahiti server listens to cal1. After its submission, the mobile agent the host's pons for incoming aglets, captures proceeds autonomously and independently of them, and provides them with an aglet context the sending client. When the agent reaches a (i.e. an agent execution environment) in which server, it is delivered to an agent execution they can run their code from the state that it was environment. Then, if the agent possesses halted before they were dispatched. Within its necessary authen~ication credentials, its context, an aglet can communicate with other executable pans are started. To accomplish its aglets, collect local information and when task, the mobile agent can transpon itself to convenient halt its execution and be dispatched

~

Mobile agents applications Intemet Research: Electronic Networking Applications and Policy Rosane Maria Martins et al. Volume 11 .Number 1 .2001 .49-54

to another host. An aglet can also be cloned or the purchase agent searches for products

disposed of. with the desired characteristics among

products of that type;

as a result of the search, Data Agents sends

Applications an e-mail or shows a screen to the user with

a list of products, their respective prices and Two applications based on agent technologies where they can be found.

were implemented in this paper: Data Agents n _{d .}

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A J.-ropose archztecture

an o a or gents.

The following architecture is proposed to

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enable the Data Agents system to have the

a a agents -a group o mo

e agents J.or

functionality mentioned above and, in the

e-commerce

Th

_{e agents for electrornc commerce consldered}

..future

_,

to be applied to many products and

in this context are those that somehow help the stores.. The system pres~nted comprises the

users to shop over the Internet. This type of

followmg components: mterface module,

agent, called shopping agent, may carry out

control module and purchase agents. What

several tasks, such as: to help the user decide

follows is a detailed list of the system

what product shou1d be purchased; to make

components.

suggestions based on its knowledge of its owner;

Inteiface ~odule. This is the component

to find out new things, discounts and special

through WhlCh the user contacts the system and

prices; to find stores that sell the desired

places his order. This module is also responsible

product or service, among other things.

for presenting the result obtained by the group

In order to show the feasibility of the search

of agents to the user.

process for structured and distributed

"Title", "author", "price range" and "type of

information through the mobile agents

itinerary" are the information that the user must

technology, this paper proposes the

provide to the interface module so that it may

development of a multiagent, mobile and

request the control modu1e to create and

intelligent system called "Data agents" in the

dispatch the purchase agents according to the

context of several "online" bookstores. The

restrictions imposed by the user.

goal is to accelerate the retrieval of distributed

There are three possibilities of choices for

strUctured information. This is achieved by

itineraries:

improving the phase of the process of data

(I) One agentfor each server. According to the

selection, in which the agents run parallel

quantity of servers registered in the system,

among the servers related to them and at the

one agent is created for each server and

end retum with alI the information requested by

dispatched to do its task. When each agent

the user, without the need to make a call to each

arrives at its destiny, it does its search,

one of the servers separately. The information

sends the result as a message to the control

obtained is then presented in a uniform and

module and "dies".

organized way. Using the information thus

(2) Only one agent that visits alI the servers.

Only

presented by the system, it is much easier for

one agent is created that has in its traveI

the user to choose a product with the most

plan the addresses

of alI servers. It will go to

satisfactory characteristics.

all servers, one by one, do the search, send

Among the possible functions described

the result as message to the control module

above, the Data Agents agent is intended to

and "dies" at the last visited server.

help find the stores that sell the desired product

(3) One agent that goes through the servers

until

an~ to list the prices of the products found.

finding the first occurrence.

Only one agent is

The operation of the prototype to achieve this

created that contains in its traveI plan the

objective is the following:

addresses of all servers. But it will traveI to

user selects the specific product and the

the next server only if does not find any

desired characteristics of that product

book at the former server, that is, the agent

(these characteristics will be the restrictions

travels until finding the first occurrence that

for the search) ;

satisfies the order user .

Mobile

agents

applications

Intemet

Research:

Electronic

Networking

Applications

and

Policy

Rosane

Maria

Martins

et al.

Volume

II. Number

I. 2001

.49-S4

As soon as the result manager (a component of

selecting only the information considered

the control module) compiles alI answers

relevant and recommended according to the

received, it sends these answers to the interface pre-determined rules. Such information shall

modu1e so that they are delivered to the user: on represent the basis of rules to be used by the

the screen or via e-mail.

agent to make appropriate decisions in the

Control module. This module is responsible for

process of evaluation of the items found.

the creation and release of purchase agents to

With this architecture, the extension of this

begin the search requested by the buyer. This

system to deal with new products and new

module also aggregates the results found by the stores is simple, although it is necessary to build

different agents. There is a control module for

a control module for each new product.

each type of product available in the system,

-"-I

~

e.g. a control module for books and a different CollaborAgents -solution for a logistic i~~~

":f;;

one for CDs.

problem applying multiagent systems

g~,

After receiving the user's requirements from

The Internet has been extensively explored as

the interface module, the control module

an environment which ficilitates integrating

creates the agents according to such

clients and suppliers willing to negotiate

requirements and sends them to the addresses products and services. Under that light, an area

available at a storage structure.

that deserves special attention is the automatic

A storage structure is a hash structure that .negotiation

betWeen clients and suppliers.

contains the addresses of the various stores

The negotiation model presented consists of a

associated with the system. There is a storage

system of agents that acts in the process of

structure for each type of product researched by integration among clients, represented by the

the system.

subsidiaries of an automaker, and a netWork of

When the control modu1e receives a request

suppliers. This system contributes to the

to send an agent, the latter is created on the

mastering of electronic commerce, since some

"aglet" layer according to user's requirements

client agents interact with supplier agents trying

and travels through the runtime layer, which

to find products and buy products that meet

converts the agent into an array of bytes and

their needs.

such array, in its turn, passes on to the ATP

The subsidiary that wishes to purchase a

layer -agent transfer protocol, to be sent to its product may ask the client agent to initiate the

destination. This protocol then builds a "bit

negotiation with a netWork of supplier agents

stream" that contains both general information,

remotely distributed on the Internet. After a

such as the system name, and its identification,

number of interactions with other agents, the

such as the "byte array" resulting from the

client agent returns to its original computer and

runtime layer.

shows the result of its negotiations, i.e. a list of

On returning to the server with the

suppliers that best fit its needs in terms of price,

information from its search, each purchase

freight cost and quantity of product.

agent sends its contents to the Result Manager

As supplier/client agents are created, they are

(control module), so that the Results Manager

sent from their original computer to an agency,

may aggregate ali answers obtained and send

where they will communicate to achieve their

them to the interface module.

overall goal. The agency, or meeting place, is a

Purchase

agents. Make contact with the stores host computer, where the agents do business.

by accessing their databases, place the order

Each agency represents a certain region. In that

and interpret the answers generated, converting respect, the client agent wil1 run the netWork,

them into a format that is understood by the

searching for possible suppliers to meet its

control module. Before proceeding to their

demands, and wil1 prioritize agencies located in

destination, the agents are coded in bit stream: regions closest to the location of the subsidiary

the first segments are general information, such represented by the agent, in order to reduce

as the agent's identification, and the last

freight costs.

segment is the byt.e array, the agent per se: code

This section of the paper wil1 try to describe

and state. The goal of the agents is to check the the components forming the model developed

information found at their destination address, and analyze its operation.

Mobile agents applications Intemet Research: Electronic Networking Applications and Policy Rosane Maria Martins et al. Volume 11 .Number 1 .2001 .49-54

Architecture of model suppliers. When the facilitator agent makes The architecture of the model is characterized enquiries the supplier agent in relation to the by the exchange of messages among three cost of the material requested by the

categories of agents: facilitator agent, supplier subsidiary, that agent is not interested in the agent and client agent. intemal details of that calculation, only in the

Facilitator agent. It is responsible for result.

managing the negotiation between client agents When the entire inventory of the supplier and agency suppliers. The facilitator agent agent has been negotiated, the agent will send a works as an intermediary for such agents. The "Unregister" message, requesting to leave the facilitator records all suppliers with their list kept by the facilitator agent. After its respective offers and indicates to the client exclusion from the database, the supplier will agent the best supplier to establish the retum to its original computer and will show to negotiation process with. The facilitator agent the user the result of its negotiation with the has an optimization module to carry out that different client agents that contacted the job. That optimization module inquires supplier agent.

whether each supplier is able to meet the Client agent. It represents the interests of a subsidiary's demand through the "SearchOffer" subsidiary. This means the demand for parts message and decides which is the most that a subsidiary is willing to buy.

favourable candidate based on which supplier A list of request of material form is opened made the best offer (lowest cost) .when the subsidiary agent is created. That form

Supplier agent. It represents the interests of will contain the subsidiary's identification, the supplier. Interests ofthe supplier means the description and location entered by the user, as offer of parts and their respective costs (unit well as the description and quantity of the price and freight) .A list of offer of material material requested, later on confirming the form is opened when the supplier agent is information.

created. The description of the part, the After that information is confirmed, the client quantity available for sale and unit price will be agent will migrate to an agency searching for the typed into the list of offer of material. best supplier to meet its demand. After arriving

After confirmation of the information typed at the agency, the agent will communicate with in the list of offer of material, the supplier agent the facilitator, which will indicate the context of will be sent to an agency. At the host computer, the best suitable supplier. On obtaining the the agent will make the first contact with the answer, the client agent will initiate the facilitator agent, subsequently requesting to be negotiation process through the "Negotiate" listed in the database by using the "Register" message. If the client agent does not find the

message. desired supplier, it will go to other agencies

The supplier agent is responsible for searching for new proposals to meet its calculating the total cost of the material demand. After completing all the negotiations, requested by a subsidiary (price of the client agent will retum to its original merchandise, including freight) .It is computer and show the results of its interaction noteworthy that the freight legislation is too with other agents.

wide and this paper is not intended to study all rules and effectiveness in each State.

Suppliers hire the service of a shipper, which Discussions and future work calculates that cost. This information will be

sent to the supplier and will become part of We have built two simple prototypes to test the the context of its agent. This case highlights basic concepts and feasibility, and conducted the main advantage of the object-oriented some simple experiments. Nowadays, the Data programming: polymorphism. Each class of Agents system presents a simplified

supplier has a different intemal policy for configuration, allowing just one kind of product carrying out the sam~ method ( calculation of to be investigated. The selected product to this freight) and the facilitator agent is not stage was "book". The purchaser agent is responsible for knowing the procedures of all created at the user machine and migrates to the

Mobile agents applications Intemet Research: Electronic Networking Applications and Policy Rosane Maria Maltins et al. Volume 11 .Number 1 .2001 .49-54

target server. This target server is an aglet server and the second, based on computational where it may be found the offered service by the intelligence, where the agents will be able to

supp1ier. make proposals through the experience that

The results obtained in this initial phase were they acquired along their lifecycle.

considered acceptable, due to the information Future work is focused on making smarter filtering executed on the server where the agents that are directable at a more naturallevel resources are located. This circumstance leads for users. Though we have only just scratched to a significant reduced netWork loading. the surface in terms of making a truly useful

The possibility of the existence of more than .

d b th k d

system, we are exclte a out ese wor s an one kind of product

b

. to be investigated is a task

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1 d . th h f th .m ey ave e c ance to essent1a y c ange

to e lmp emente m ano er p ase o lS

. An th ..the way people acquire goods and services in

proJect. o er 1Inprovement lS an

the not-too-distant future.

lmplementat1On of an mtell1gent module that

permits the Data Agents system, besides the

conventional search, to make suggestions to the

user.

References

Conceming the CollaborAgents system, a

1 .. d 1 . 1 d 1 th Bond. A.H. and Gasser. l. (1988). Readings in Distributed

oglSt1C mo e was 1ffip emente to so ve e. ...

Art,f,Clallntelhgence. Morgan Kaufmann. San Mateo.

issue of automotive parts distribution. In this CA.

case, each subsidiary and supplier creates an Chavez, A. and Maes, P. (1996), "An agent marketplace for agent which shares information seeking for a buying and selling goods". Proceedings of the First

global solution. International Conference on the Pradical Application

From this experimentation, good results were of Intelligent Agents and Multi-Agent Technology. obtained, once the implementation of mobile london. April.

agents avoided the overload on the Web. In a Chess. D. et al. (1993). "Itinerant agents for mobile

h .. d .. h computing", IEEE Personal Communications, Vol. 2

next stage, a sop lSt1Cate negot1at1on sc eme

5 O b

fi b . 1 No. .cto er.

or uyers and sellers wll be developed. We are General Magic Inc. (1998). Mobile Agents, available at studying tWo models: first, involving http:llwww.genmagic.com

"price-raise" and decay functions similar to IBM Japan Research Group (1988). Aglets Workbench. Kasbah's technique (Chavez and Maes, 1996) available at http:llaglets.trl.ibm.co.jp