Multiple Character-Agents Interface: An Information
Integration Platform Where Multiple Agents and HumanUser Collaborate∗

Yasuhiko Kitamura and Hideki Tsujimoto

Teruhiro Yamada and Taizo Yamamoto

Graduate School of Engineering
Osaka City University
3-3-138 Sugimoto, Sumiyoshi-ku, Osaka
558-8585, Japan

Laboratories of Image Information Science andTechnology, Japan†kitamura@info.eng.osaka-cu.ac.jp
ABSTRACT1.

We propose the Multiple Character-Agents Interface (MCI)
as an information integration platform where multiple animated life-like characters interact with each other and withthe user to retrieve and integrate information from the Internet. The MCI makes the process open to the user and allows
him/her to collaborate with the character-agents. We implemented the MCI as a multi-agent system in which information agents distributed over the Internet are integrated,then we developed a prototype called Venus and Mars, which
is a cooperative cooking recipe search engine consisting of
three character-agents that collaborate with the user to locate cooking recipe pages.

World Wide Web can be viewed as an open information system on the Internet from two viewpoints. Firstly,
it is open to information providers. Once an information
provider installs and starts a Web server on a computer connected to the Internet, he/she can immediately disseminate
information toward the world. On the other hand, it is noteasy to retrieve and integrate information from the Web
because related information tends to be scattered among
a number of sites. Various search engines, information integration systems [2] and information agents [3] have beendeveloped to deal with the problem.
Secondly, the Web is open to information users. The Internet is spreading into our society deeply and it becomes
one of social infrastructures which support our daily life.
The range of users is spreading from computer experts tonovice users such as children or elderly people. At present,Web browsers are a most widely used tool to get accessto the Web, but in the future, more user-friendly tools orinterfaces, which even novice users can easily handle, areexpected. To this end, various life-like character agents [1]have been developed and some character agents such as developed by Extempo have been ready for e-commerce. Theseagents can chat with the user in natural language such as
English or Japanese and help him/her navigate the Webwith gestures.
Conventionally, each of the above two approaches has
been discussed as an individual research topic. In this paper,
we rather integrate these approaches into a single platform
called the Multiple Character-agents Interface (MCI) wheremultiple information agents, each of which has a character interface, interact with each other and the user. On theMCI, the information agents can collaborate with each otherfor retrieving and integrating information to meet the user’s
demands and the user also can interact with the agents toimprove their behaviors or to change the team of agents ina flexible manner.

Categories and Subject Descriptors
H.5.3 [Information Interfaces and Presentation]: Groupand Organization Interfaces—collaborative computing, Webbased interaction, character agent ; H.3.3 [Information Storage and Retrieval]: Information Search and Retrieval—search process

General Terms
Multiple character-agents

Keywords
animated character, interface agent, information agent, information retrieval, information integration∗Presently with SANYO Electric, 3-10-15 Hongo, Bunkyoku, Tokyo 113-8434, Japan†Presently with NTT Braodband Initiative, 2-2-2 Otemachi,Chiyoda-ku, Tokyo 100-0004 Japan

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2.

INTRODUCTION

MULTIPLE CHARACTER-AGENTS INTERFACE

We show the components of the Multiple Character-agentsInterface (MCI) in Figure 1. We here presume that an information agent consists of a body part and a header part.

• Agents work in collaboration to assist the user in retrieving and integrating information. By showing thecollaborative process of information retrieval and integration to the user, he/she can intuitively understandwhat happens in the system. Furthermore, he/she canchange or modify agents in progress according to thetask or his/her preference.

that include keywords about recipe, such as “I would liketo eat a pork dish,” as a query. He extracts one or more
keywords about recipe (“pork”) from the utterance and submits the keyword(s), with keyword spices[4] for the recipedomain, to a general-purpose search engine. He receives
search results from the search engine and shows them to theuser through the Web browser. In case he receives too many
results, he automatically asks for additional keywords about
seasoning or type of recipe (Western, Japanese, Chinese, andso on) to reduce the number of results. To the response fromthe user, he resubmits a query with corresponding keyword
spices about seasoning to the search engine.
Cho-san is another type of information agent that has
knowledge about cooking ingredients and health in his local
database. Responding to an utterance that includes keywords related to cooking ingredients or health, he utters acomment about the relations between cooking ingredientsand health, such as “Leeks are good for colds.” As an example of collaborations among agents, Cho-san can assists
Kon-san. When Kon-san cannot answer the request “I wanta recipe that is good for recovering from a cold.” because
he has no knowledge about health, Cho-san can make acomment “Leeks are good for colds.” Kon-san takes thecomment as a clue to initiate a new search with the keyword “leek.” This type of collaboration shows a potential of
VandM for realizing various type of information search byadding agents to the team.
Pekko is the personal agent; she initially appears on theclient machine and calls other agents. She then monitors theuser’s utterances. When needed, she suggests some search
keywords on behalf of the user referring to the history ofuser’s utterances. For example, if the user expresses a preference about seasoning when asked by Kon-san, Pekko storesit in her local database and expresses it on behalf of the user
at the same situation in the future. As another example ofcollaborations among agents, Pekko assists Kon-san in reducing the number of search results. When Kon-san asks
for a tip on seasoning, Pekko can answer “I know Kitamurasan likes Japanese food.” by referring to the interaction
history of user. If the user does not like Pekko’s suggestion,
he/she can correct Pekko’s utterance by indicating his/hertrue preference directly to Kon-san through the dialoguebox. Pekko recognizes this correction and updates the user’s
preferences stored in her local database. Monitoring interactions between agents and the user, Pekko learns the user’spreference.

• The user can flexibly build a team of agents for integrating information by choosing his favorite agents.

4.

User

Figure 1: Multiple Character-agents Interface.
The body part of agent resides in an individual serverwhich is distributed over the Internet, and works as an information gathering engine that retrieves domain-specific information by using a search engine or a database. A personal
agent in Figure 1 is also regarded as a special-purpose information agent though it resides in the user’s machine andhandles and stores the user’s profile for assisting his/her information retrieval task.
The header part of agent is embodied by using an animated life-like character interface such as the MS-Agentplatform. The user can get access to the agent by clicking itand giving a message. The agent can respond to the messageby talking with a gesture.
When the user invokes an information agent, the characteragent (header part) is loaded into the MCI on a client machine of the user. The character agent can interact not onlywith the user but also with other character agents whichhave been loaded on the MCI. Collaborative actions among
information agents for retrieving and integrating information are performed by character agents on the MCI and displayed to the user.
The advantages of the MCI are summarized as follows.
• It provides a friendly interface between the user andinformation sources.

• Some agents are proactive in a way that they can suggest proper keywords for information retrieval.
• By interacting with the user, some agents can discover
his preferences and can use it for assisting his/her future information retrieval tasks.

3.

VENUS AND MARS: A COOPERATIVESEARCH ENGINE FOR COOKING RECIPE

Venus and Mars (VandM) is a cooperative search engine inwhich three character-agents; Kon-san, Cho-san, and Pekko,
work cooperatively to search for cooking recipe pages.
Kon-san is the information agent that locates Web pages
about cooking recipe. He can accept a Japanese utterance

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