Internet Agents for Telemedicine Services. * Dept. of Pathology, University of Udine, Italy ** Dept. of Informatics, University of Udine, Italy

Transcription

1 Internet Agents for Telemedicine Services Vincenzo Della Mea*, Vito Roberto**, Antonello Conti**, Luca Di Gaspero**, Carlo A.Beltrami*. * Dept. of Pathology, University of Udine, Italy ** Dept. of Informatics, University of Udine, Italy Corresponding author: VINCENZO DELLA MEA Dept. of Pathology, University of Udine Piazzale S.Maria della Misericordia - Udine Italy dellamea@dimi.uniud.it Phone: Fax: SHORT TITLE: Internet Agents for Telemedicine Published in: Medical Informatics & Internet in Medicine (formerly Medical Informatics) 1999; 24:

2 Abstract Telemedicine can be viewed as the telematic support for collaboration among distant medical professionals, which cooperate on shared resources of various kind. In light of this, attention to telematics and informatics concepts particularly oriented towards collaboration should be paid: in particular, the recently appeared agent paradigm seems suitable for the analysis, design and development of telemedicine services because of its committment to intercommunication and sharing of resources. The present paper is aimed at introducing the agent paradigm, from the theoretical basis up to the technological issues, and at describing an agent-based approach to telemedicine, specifically applied to telepathology applications. The described system is based on an agent-based tool (JAMES), namely an agent model and template implemented using Java, which has been used to implement a prototype multipurpose telepathology application based on a federated agency architecture. Keywords Agents, Telemedicine, Internet, Telepathology

3 Introduction Telemedicine has several definitions, based on the technological as well as on the clinical aspects of it; which can be summarized as "the practice of medicine at distance by means of telematic tools". However, the attention can be drawn on another way of viewing telemedicine, that is, as the telematic support for collaboration among distant medical professionals. Collaboration involves communication and sharing of resources, which can be of various kinds, including: - data: multimedia patient data (e.g. not only descriptive, textual information but also diagnostic images, audio and other one-dimensional measurements, 3D data sets, etc.); it is the basic resource exchanged in telemedicine, being the basis for almost every activity. - expertise: every time an opinion is requested, exchange of specific expertise occurs. This is an untouchable but extremely valuable resource, and, in telemedicine, regards mostly diagnosis, prognosis and therapy. As an example, remote expert consultation is strictly related to the delivery of expertise. - processing: specific data processing is sometimes possible only in some site, usually because it needs either particular expertise, or particular hardware/software configurations not available everywhere. Processing activities which can exploit telemedicine tools are image processing (e.g. 3D reconstructions, quantitative evaluations, etc.), and statistical data analysis. In the recent years a new computing paradigm was born, in which software programs can be seen as autonomous, social, and reactive components called agents; these modules are able to act in a specific environment, also without any direct input, in order to fulfill their design specifications, responding to external changes, and eventually communicating, when needed, with other agents by means of an agreed upon language (1). This approach helps to design complex systems, where different intercommunicating functionalities are implemented using dynamic and distributed components which may change over time. Sometimes, these modules incorporate legacy software and/or data, and thus have the need for a common basis for communicating the data they are using, as well as the metainformation about tasks and services being provided. The agent paradigm involves not only an implementation practice, but also the analysis and the design step of a system project; this is achieved by means of agent development tools or agent frameworks where the system designer work is naturally driven by the agent concept, exactly as object oriented tools help in analysing, designing and implementing object oriented systems. Agents are particularly fashionable on the Internet, because of the intrinsically distributed and dynamic nature of the resources available on it: quite a lot of different computers are involved, hosting continuously coming up, changing and disappearing resources. For this reason, user-supporting agents have been developed, which try to help the user in accessing Internet resources through different modalities (search, information filtering, change detectors, and so on). Although this kind of software

4 does not correspond very often to the agent concept, being more likely based on the client/server paradigm, the user agent, seen as a personal assistant, is one of the most important and described among agent categories. The present paper aims at demonstrating how the agent paradigm can be applied to the analysis, deisgn and implementation of telemedicine services which use the Internet as a communication mean. Objectives The main goal of the present work is to describe the agent paradigm from the point of view of telemedicine, and to present a prototype application of such an approach in the field of telepathology. A scenario An example scenario can be useful for understanding how to fit telemedicine inside the agent paradigm. A pathologist, during his diagnostic routine, finds a particularly doubtful case, and wants to send it to an expert in the specific field. First, he tries to locate similar cases on some case archives on the Internet, by means of his user agent (UA); he can also send a number of images (i.e. immunohistochemistry stainings) to an agent able to do automated quantification through morphometry techniques (2). If this is not enough to state a firm diagnosis, he acquires representative images from the microscope always through the UA, which, in the meantime, looks for patient data inside the old HIS, suitably wrapped by another agent which allows to communicate with it in a standard language. When the multimedia case is ready, the UA requests a broker agent to pick out an expert in the field related to the case, and to initiate the transaction for a consultation with him. The case is then sent using multimedia . When the case arrives at destination, the expert looks at the case with his UA, and eventually calls the referring pathologist agent for a live discussion on the case using the whiteboard and chat facilities embedded in the UA. When done, the expert sends back his written and electronically signed diagnosis to the referring pathologist, whose UA provides for its automatic insertion in the patient record, and starts the payment procedures. If the two pathologists decide that the case is potentially interesting for their colleagues, they can also collaboratively edit and submit it to a peer-reviewed case archive, which can be used by other pathologists either as a support during diagnostic practice, or for continuing medical education. Of course, this opportunity is managed by the UA too, possibly cooperating with a broker agent able to ddress the case to the most adequate case archives. The described scenario involves a few agents which communicate on the Internet, by connecting people and other software agents able to perform tasks ranging from databases querying, retrieval and insertion, to multimedia communication, CSCW support, planning, and so on. Being this the kind of behaviour we would like to see in a telemedicine system, the goal is to understand how to realize it. Methods The agents paradigm

5 Although no widely accepted definition of agent is currently available, a general one which can be used to loosely characterize an agent has been given by Russel and Norvig (3): an agent is anything that can perceive an environment by means of sensors; it can act upon the same environment through effectors. There are also a few properties commonly accepted in describing agents: - autonomy: an agent embeds an internal state, and controls its own actions without external intervention; - sociality: an agent interacts on a peer-to-peer basis with other agents by means of an expressive agent communication language (ACL) (4) - reactivity: an agent can react to changes in the environment; - proactivity: it does not simply act in response to the environment but it shows opportunistic behavior, trying to fulfill its design specifications. Giving a notion of agency is the main goal of agent theories, wich are essentially agent specifications: formalisms and ways of describing the desiderable features of agents. the most important basis for agent theories is the intentional system concept of Dennett (5), which indentifies an entity 'whose behaviour can be predicted by the method of attributing belief, desires and rational acumen'. Agent theories usually adopt some human-like intentional attitude (e.g. belief, desire, intention, obligation, committment, choice,...) as an abstraction tool to describe agents and their behavior using some formalism (e.g. logics). Once defined the agent, communication among agents should be modelled. For this, the theoretical basis has usually been the Speech Act Theory (6): communicative expressions are actions exactly as physical actions are, directed to produce a change in the world (in particular, in the mental state of the listener). The construction of agent-based computer systems that satisfy the properties described by agent theories is the goal of agent architectures. Architectures fall into two main categories (7): deliberative and reactive. The former is the classical approach where agents are viewed as particular knowledge-based systems, with an explicit symbolic representation of the world on which reasoning is made to decide and act. The latter is based on the Brooks' subsumption architecture [8], where no explicit representation of the world neither explicit symbolic reasoning are needed to obtain intelligent behaviour, ad intelligence is an emergent property of some complex systems. Starting from theories and architectures, some tools for agent development has been created: such tools allow for analysis, design and programming systems in an agent-based fashion, by giving the designer/programmer the capability of creating systems in terms of some of the concepts above described. An example is the agent-oriented programming paradigm [9], where intentional notions are directly used to develop agent-based systems. Another interesting topic is that of how agents can cooperate inside agent communities, with all the issues growing up when dealing with social capabilities. Two main approaches can be distinguished, one based on an information sharing model, and one based on the so-called federated systems. In the former, each agent can advertise each other about their capabilities and needs. In the latter, some level of organization is given by grouping agents in federations (on a task or geographic basis), with a unique access point to

6 them constituted by a specific agent called facilitator; this way, agents need only to advertise their needs and capabilities to their own facilitator, which acts as a broker to and from the external agents [4]. The JAMES agent model In our approach, based mainly on the Genesereth idea [4], the most important feature of agents is communication. To this, we designed a model for agent based telemedicine services based on KQML [10] as communication language among agents, and a common markup technology for coding and storing multimedia documents, based on RDF [11] and currently being developed with XML [12]. Briefly, KQML (Knowledge Query and Manipulation Language) is a communication protocol developed inside a larger project, namely KSE (Knowledge Sharing Effort), which gives a framework for knowledge exchange among knowledge-based systems. In particular, KQML is a language-independent protocol, with a Lisp-like syntax, where messages are called performatives. Performatives embody a content, declared in any language, and specify the kind of speech action (e.g. tell, ask, reply, perform, etc.). RDF (Resource description Framework) is a metacontent formalism being developed, together with XML (Extensible Markup Language), inside the World Wide Web Consortium. The basic component of our agent architecture is JAMES (Java Agent Model for Enhanced Services), which is a Java package implementing the basic functionalities of a generic agent [13]. It includes KQML communication, management of multimedia documents, a virtual knowledge base, multithreaded execution of tasks, and support for the developer in the form of high-level methods to build agents. As a matter of fact, JAMES can be specialized in order to accomplish particular tasks, as well as to create a hierarchy of more specific, but yet generic agents (i.e. data manager agents, brokers, interface agents, etc.), which can be further exploited to create instances of practical use. JAMES by itself is composed by a head, responsible for communications and the management of knowledge, and a body, which actually executes performatives (figure 1). The communication occurs through the Internet, by means of TCP/IP, SMTP and FTP low level protocols and, at a higher level, by means of the KQML communication language. Hypermedia data management is realized through a support library, called HYPERFRAME, which is in turn based on an ontology of hypermedia documents written using RDF. The implementation is built with the Java language, in order to exploit its multi-platform and networking capabilities, and on the JATLite package [14], which supplies a complete KQML implementation. The MANTHA agency architecture MANTHA (Multi Agent Network for Telematics and Hypermedia Applications) is a generic agent-based architecture for the management of hypermedia documents, which is currently developed at the University of Udine, Italy. It is based on the federated approach, with agents grouped on a task basis, i.e., agents cooperating on the delivery of a specific service are federated together with a facilitator giving access to them. In addition, it comprises also a users space, composed by user agents able to access the federation.

7 As a prototype application, MANTHA has been specialized for telepathology, by identifying three main activities that can be carried out on the Internet through this model: multimedia case delivery, publishing and archiving. The first activity corresponds to the usual transmission of pathology cases (comprising text and microscope images) for expert consultation aims [15]; publishing of multimedia cases consists in the creation of a multimedia case report database, which can be contributed following the usual publishing rules (submission, peer review, and publication or rejection), and publicly accessed for education or support to diagnostic practice; and finally, cases can be simply archived for future consultation. Generic classes of agents supporting the above described activities have been individuated, including database manager agents, agent resource brokers (acting as facilitators for federations), mail and WWW wrappers (managing the interoperability between federations and mail and WWW protocols respectively), hardware and software encapsulators (the former for accessing hardware devices, the latter for masking the access to legacy software). Figure 2 outlines the architecture of the whole telepathology federation. Preliminary results and discussion The architecture has been tested through a prototype implementation which includes: - a user agent, specialized for pathology cases, which allows for authoring cases and accessing services provided by other agents (figure 3); - a multimedia case publishing system, in the form of a federation of 4 agents, which allows to publish on the WWW case reports, creating HTML files from RDF-encoded hypermedia documents, putting them on a WWW site and updating the appropriate index files; - a case archiving federation, implemented by wrapping a SQL engine with a database manager agent; - a general services federation, in which wrappers for mail and Web protocols are realized; this federation can be used for delivering cases through , i.e. for exchanging cases directly among users. Each agent has been implemented by using the JAMES agent model, which appears to be a practical development tool for quickly prototyping agent-based applications, and also for making legacy software intercommunicate: in fact, some developed agent encapsulate already existing protocols (such as SMTP, POP3 and HTTP), while some other wraps traditional software (such as SQL engines). Due to the use of Java, the whole agent community is potentially portable on every platform, although some of the described agents will likely be resident on server-class machines, typically running Unix and derivates as operating system. On the other side, the target systems of the user agent will be any kind of personal computer; for this, the user agent has been tested on Unix, Linux, Windows95 and MacOs 8 systems, evidentiating problems only on MacOs. Conclusions The agent approach seems suitable for telemedicine because of its commitment to intercommunication, crucial topic in any collaborative activity as telemedicine. Furthermore, the variety of interconnected and

8 distributed resources proper of medical data and tasks makes the agent paradigm a good choice for the analysis and implementation of medical systems, as already done in the field of patient management by Lanzola et al. [16] and Hayes-Roth et al. [17]. In our approach, the attention is mainly focused on communication of multimedia patient data being based on the same resources and structures, although with different aims: expert consultation, publishing, and case archiving. The choice of RDF as metadocument formalism ensures the future easy interconnection with the World Wide Web, now evolving towards the use of RDF and XML, but apart from this, it makes data widely reusable and interchangeable. The next step, currently ongoing, is the thorough evaluation of the architecture in a more user-centered set-up; in particular, the system is being adopted for the educational support of a nation-wide network of postgraduate pathology schools. Future developments include mainly an enhanced management of the virtual knowledge base, the extension of the hierarchy of generic agents by analyzing the most used agent categories, and some more extensive tests about the performance. Acknowledgements The present work has been carried out with the partial support of the Consorzio Universitario del Friuli. References 1. Jennings, N.R., Woolridge, M.J. (1998). Agent Technology Foundations, Applications, and Markets. (Berlin, Germany: Springer-Verlag). 2. Roberto, V., Della Mea, V., Beltrami, C.A. (1997) Imagencies: Network Image Services for Medical Applications. Dept. of Mathematics and Computer Science, University of Udine, Research Report UDMI/10/97/RR. 3. Russel, S., Norvig, P. (1995) Artificial Intellience - A modern approach. (Englewood Cliffs: Prentice Hall International). 4. Genesereth, M.R., Ketchpel, S.P. (1994) Software Agents. Communications of ACM 37, Dennett, D.C. (1987) The intentional stance. (Cambridge, USA: MIT Press). 6. Searle, J.R. (1969) Speech Acts: an essay in the philosopy of language. Cambridge, UK: Cambridge University Press). 7. Wooldridge, M., Jennings, N.J. (1995) Intelligent agents: theory and practice. Knowledge Engineering Review 10, Brooks, R.A. (1991) Intelligence without representation. Artificial Intelligence 47, Shoham, Y. (1993) Agent-oriented programming. Artificial Intelligence 60, Finin, T., Labrou, Y., Mayfield, J. (1997) KQML as an agent communication language. in: Bradshaw, J. (Ed.), Software Agents, (Cambridge, USA: AAAI Press/MIT Press).

9 11. Lassila, O., Swick, R.R. (1998) Resource Description Framework (RDF) Model and Syntax Specification. W3C Working Draft 20 July 1998; Bray, T., Paoli, J., Sperberg-McQueen, J.M. (1998) Extensible Markup Language (XML) 1.0.W3C Recommendation 10 February 1998; Brunato, D., Conti, A., Di Gaspero, L., Della Mea, V., Roberto, V. (1998) An agent-based approach to the delivery of telepathology services. In: Proc. of 4th European Congress on Telepathology, Udine, Italy, Advances in Clinical Pathology 2, Heecheol, J. (1997) JATLite. University of Stanford, Della Mea, V., Beltrami, C.A. (1998) Telepathology applications of the Internet Multimedia Electronic Mail. Medical Informatics 23, Lanzola, G., Falasconi, S., Stefanelli, M. (1995) Cooperative software agents for patient management. Lecture Notes in Artificial Intelligence 934, Hayes-Roth, B., Larsson, J.E. (1996) A domain-specific software architecture for a class of intelligent patient monitoring systems. Journal of Experimental and Theoretical Artificial Intelligence 8,

10 Figure 1: the JAMES agent model. KQML JATlite TCP/IP HEAD communication perception BODY VKB (Virtual Knowledge Base HYPERFRAME Knowledge, Ontologies Hypermedia Data management action processing

11 Figure 2: The MANTHA federated architecture. FEDERATIONS SPACE Indexer ARB agent resource Publisher broker USERS SPAC SQL engine SMTP wrapper HTTP wrapper POP3 wrapper HTML generator ARB agent resource broker ARB agent resource broker UA UA WWW browser

12 Figure 3: The interface of the user agent.