Proceedingsof the 28th Annual Hawaii International Conferenceon SystemSciences- 1995
A Communication Framework for Applications Scott A. Moore Computer& Information SystemsDepartment Schoolof BusinessAdministration University of Michigan The form of cooperative business relationships will change-the partners will becomemore tightly interwoven. The number of cooperativebusinessrelationships will increase. The scope and depth of such relationships will increase. The technology will enable these relationships to extend and evolve over time, benefiting both parties. First-movers to such a technology will, for a time, have a competitive advantageover other firms. We want these benefits but we do not want to endure the long developmentcycle and incur the large, up-front idiosyncratic investment. We want it to be easy to create a CBA. We want to maximize the reusability and extendibility of the CBA. We want it to be easy for applications to send and receivenew messages.We want idiosyncratic investment to be pushed to later in the developmentcycle. This delay has severalbenefits. The company can investigate more applications without having to make a large commitment to that application. Also, the delay allows the company to get a better idea of the project payoff. This helps the company determine the extent of future investments in this project [ll, 191. Finally, we want tools used in the development of one CBA to be useful in the developmentof the next CBA. Clearly, we want these benefits. Equally clearly, current technology does not give them to us. Reusability and extendibility are the key attributes of the desired,and so far elusive, solution. The main componentsof a CBA are the messagesthemselves and the procedures that handle the messages. We should focus on these if we want to construct a CBA that has theseattributes. In this paper I describe a general language for messagesand a logic model for a general method for handling messages. The languagedescribedherein is an extension of the formal language for businesscommunication (FLBC) previously put forth in [2O, 21, 28,291. The messagehandler is an extension of that presentedin [28]. The entire sys-
Abstract The author proposes a communicationframework for applications that is reusable and extensible. An existing recursively defined language is modified so that the message interpretation scheme can determine whether the message is meant to be interpreted literally or not. This makes it possible for the system to take advantage of its foundations in speech act theory with a minimum of inferential overhead. It is also extended to incorporate discourse management information. The author recommends that discourse be represented in a general planning language such as Petri nets. Actual discourse is allowed to deviate from these plans in unexpected ways so applications get the benefit of automated message management but without the inflexibility this usually requires.
1.0 Introduction A confluenceof hardware and software developments has made possible the development of communication basedapplications (CBA@ such as electromc data interchange (EDI), document management, and groupware. These applications generally require that developersdefine a set of standardmessagesthat can be sent, received, and interpreted. If this is a new application area, this entails much committee work and a general commitment of time for developerswho must try to foreseemessages the applications will need to perform their tasks. Through a long iterative developmentcycle they defme a standard that satisfies the basic functions of the application. The long development cycle and large, up-front idiosyncratic investment in CBAs deters companies from developing them. This is unfortunate since the industrial-organizational benefits of the widespread use of theseapplications are exciting [20]:
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Proceedingsof the 28th Annual Hawaii Intemational Conferenceon SystemSciences- 1995
temdiffersfi0mthosediscussedinthesepapersinthat themeasagesaremoreliteralandthesyaemsdoles infenmcing upon receipt of the messages.7% system is an ttttrdve campanise behwen the expressive,highly flexiblecofnm~capaMEiryofthesystem3presentedinthosepapersandtherigidthoughpre45secommunication cap&i&y of systems in current practice. ‘I%esetwopiecesfwmaCBAfiamewakthatiareusable and extensible.
the fact that they knew...” I take similar shortcuts elsewhere.) No uncertainty is involved other than that brought about by doubt about the m-free transm&sion of the message. qgnrre 1: An example EDI mawago C IBCGV2L
Sender (Canadian Imperial Bank) 500 Message Type (this is an order to buy) CRITGB22 Receiver (Credlto ltallano) :PO:NAL 2121 Transaction Reference Number :23:REGULAR Further ldentlfication (process normally) :30:920730 Expiration Date of Order (30 July 1992) :35A:SHSlOOOO Quantity of Securities (10,000 shares) :35B:ISIN IT0000456781 Identification of Securities PIRELLI SPA :32L:ITL2950 Price Llmlt :67A:FREE Receiver of Securltles CCOMITMM (receive free at Credlto Commerciale) :86A:CHEMGB2L Beneficiary of Securities (Chemical Bank) :71 DYACCFEE/409532 Account for Fees
2.0 Current practice, an alternative, and -8 to change In this section I describe the standard model of electronic communication,my proposedalternative, and reasons that the altemative might be preferred. 2.1 Standard model of ekctronic communication The standard model of electronic communication is simple: one application tells another to do something and it does it. For example, consider the following scenario from [42, pp. 16-lo-16-161. On 20 July 1992, the Canadian Imperial Bank of Commerce,London, asks Cmdito Italiano, London, to buy 10,000Pi&i Spa sharesat a price not exceeding ITL 2950 within a time limit of tkzndays. On settlement day, the sharesare to be delivered fxeeto Credit0 Commerciale,Milan, to be held in favor of Chemical Bank, London. Payment to the Seller will be made separately;fees for this punzhaseare to be charged to account409532. The ED1 message in Figure 1 is sent from the Canadian Imperial Bank to Credito Italiano. The left column containsthe ED1 message;the right column is an explanation of the message. A translation into the form of predicate logic gives us message(1). (The format of this particular messageis not arbitrary; it is explained later in this paper.) When the application at Credit0 Italian0 receivesthis message,it automatically validates the message,arranges for the purchase, sends a purchase confirmation, and sendsa trade confirmation. A model of this processis in Figure 2. The developers of the sending and receiving applications had previously agreed on the structure (if not the details) of what the receiving application is to do when it receives this message. When the Canadian Imperial Bank sendsthe message,it knows what Credito Italian0 is going tn do. (This bit of personification is shorthand for “The developers at Canadian Imperial Bank designed the program so that its actions reflected
(1)
rnsg(‘CIBC682L’, ‘CRITGB22’, order, buy(qty(‘SHS’, 10000), security(id(‘lSIN lTOOOO456761’,‘Pirelli Spa’)), price(limit(‘lTL’, 2950)), [dealType(lREGULAR’), order(exp(date(92, 7,30))), security(receiver(‘FREE’, ‘CCOMITMM’)), security(beneficiary((‘CHEMGBPL’)), acctFees(409532)]), 0, ref(‘NAL 2121’))
Figure 2 handleMsg(M) if orderToBuy(M), orderlsValid(M), arrangeForPurchase(M, Purchaselnfo), sendPurchaseConfirm(M, Purchaselnfo), sendTradeConfirm(M, Purchaselnfc).
Although the above describesa specific messageand how certain applicationshandle this message,many of its features are common to many--if not most~lectronic transmissions. These features make it more or less attractive for a particular application. l Messagesare simple to process. The purpose of the messageis explicitly represented. There can be no 331
Proceedings of the 28th Hawaii International Conference on System Sciences (HICSS '95) 1060-3425/95 $10.00 © 1995 IEEE
Proceedingsof the 28th Annual Hawaii International Conferenceon SystemSciences- 1995
misunderstandingas to what the sendermeans by the message. This makes in~retation of the message straightforward. l The expressivenessof the standardis tied to the grammar. If the partners want to say something new, they must define the format of a new message. This makes it difficult to add new messagesto the standard but makes it easier to process the messagesthat are defmed. l Interpretation of one messageis independentof interpretation of all other messages. Each messagehas to have its own messagehandler (as shown in Figure 2). Actually, some messageswould have to have multiple handlerssince some messagescan be used for multiple purposes. For example, S.W.I.F.T. Message510 can be either a confimMon of purchaseor a confiiation of sale. What we would like is just the opposite: One messagehandler processesmore than one message type. l When a company composesand sends a message,it sayswhat it means and means what it says. This is in contrast with human communication which is filled with indirect, non-literal, metaphorical, allegorical speaking that is, nevertheless, usually well understood. This is regardedas inappropriate for electronic communication. Companieshave perceived this model as beii effective for developingCBAs but now we want more. Now let us look at an altemative to the current model and the benefits we can derive from it.
l
l
l
l
l
l
2.2 Description of an alternative model and its benefits l
Fredicates are described by a declarative representation that enables applications to easily imerpret new memages. Messages am categorized according to a theory of aahxal language communication. Reasons for applying this theory to electronic communication are givtmh93. Theresultisthatdeveloperscancreate reusabletool kits for handling thesemessagetypes. Depending on the demands of the application, the messagescan either directly or indirectly representthe meaning of the message. Direct representationallows efficient interpretation of nmsage~while indirect representation is more flexible and is required for supporting human communication. The speaker sends information with the messagethat he considers to be its relevant context. In addition to the message’stime and origination,the context can &scribe both the message’s relationship with other messagesand the message’s position in a goal-directed conversation. A declarative representationof a discourseprocessfor accomplishing a task can be defined. This discourse model describeshow tasks should be performed but allows deviations from the model This allows automatedmanagementof conversations. The model is expressed in a generallanguagefor modeling processes. In practice, digressionsfrom the normative model can be handled by cmtextual information in the message. This allows the clarifications and interruptions that can naturally occur in any dialog to be gracefully incorporated into the conversation without making the normative models unnecessarilycomplex. The
message
structure
allows
the
speaker
to
indicate
that the messagedirectly representsthe meaning. The receiving application does not have to abey this signal. The receiver will be doing so at its own risk, knowing that the senderhas indicated that it is saying what it means and the messagemeans what it says. This signaling allows efficient interpretation of the message. l Even when a messagedirectly representsits meaning, the application’s responseto the messageis not completely determined. Particulars of a message’scontext combined with its meaning fully determinehow the application processesa message. This model goes a long way towardcreatingan environment that encouragesthe developmentof CBAs. Tool kits for handling messagesare reusable. Familiarity with the tool kit, gained through development of a CBA, increasesproductivity in the developmentof each successive CBA. The vocabulary is extensible since a new term can be added by creating a declarative representationof
Communication betweenapplications doesnot have to be structured as describedin the above model. Our goal is not to just get applications to successfully exchange dam but to encourage8 rapid developmentof many applications that can communicatewith a broad range of messages. Faster processorsallow us to make choices that were not previously possible. Also, we now understand more complex communication models well enough that we are able to computationally model them. In the following I describean alternative model that takes advantage of these more powerful processorsand our understanding of human communication. In §4.0 I present someof the model’s specifics. l As with natural language, the expressivenessof the standard is tied to the vocabulary. To say something new merely requires combining existing vocabulary in a new way. A recursively defined message structure
makes this possible. 332
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Proceedingsof the 28th Annual Hawaii International Conferenceon SystemSciences- 1995
thenewterm. Thismakesiteasyforapplicationsto pmcessnewmessagessincethedefaultre5ponsetoa messageis defined by a combination of the declarative reprewntationofthetennandthemessagehandler1From the toolkit. After progmnmers gain exptdence with this new model, idiosyncragiGinvestment is decreasedin several ways. It is easier to define new messages, methodsf~proces>hemessages,anddiswrse models that accomplish certaiu tasks. Usersmust still do this work so the investment is reduced though not
Though the above systemsare not appropriate, they do raise some h&resting possibilities. Human use of language is a powerful communication tool. We communicate by combining a pow&l, recwsiwly defined grammar with a large vocabulary [36]. We utter scmwhhg by combining words from the vocabularyin acco&nce with the rules of the grammar. Neither new words nor new grammar NhS am requjred for most utterances. We are also able to talk about the vocabulary and grammar within the language. Dficulties with this systemfor our purposesare that the processing rules are complex and sentencesare not structured enough to be easily processable by computers. This line of inquiry is promising enough that several researchershave investigated ways in which the human communicationsystemcan be adaptedfor computers. (In fact, that is what this paper is about.) These adaptations range from simplifying the language to simplirying the processof understaudingthe language. m need a deep understanding of human communication before they can adapt it for computer based commuuication. I do not attempt to provide this here but mde an overview of some of the most pertinent observationsmade by philosophers and linguists. I also relate these observations to designdecisionsfor the CBA. One conmversy is whether or not the processof understandinggn utteranceis 8 basedon &coding or cm inference (see [43] for a good discussion of this topic). Under a decoding theory, the recipient knows precisely what the speaker intends the recipient to do once the messageis decoded. Sea& [40,41] is one of the major proponents of this theory. Searle contends that utterances are understood through an application of rules of interpretation. This is similar to the usual model of communication mentioned above in the discussionof Figure 2. An inferential theory presents a more complex description of the understandingprocess. I simplify it here. Under an inferential theory the recipient mwt first infer what the speakermeans and then take the messageas a basis of inference for how to act. The recipient might take into accountprevious messages,who the speakeris, when the messagewas sent, and what was said (among other things). A messageis interpreted, not individually, but in the context of the conversation of which it is a part. Grice [13,14] is a main proponent of this theory but psychologists and cognitive scientists have also weighed in on this side of the controversy [3, 431. Sperber& Wilson [43] propose that the proper model is actually a combihtation of inference and d&oding. Philosophersdisagreeabout uot only whether a decoding or inferential model is correct but also disagreeabout the form of the decoding or inferential model itself.
NllkOWd.
3.0 Influential sptem, frameworks, and ww%~ The abovemodel doesnot exist in a vacuum; rather, it is related in many ways to the standardmodel of communication (describedin 2.1) and many other communication systems and languages described in the literature. The following describesmany of these systems. This allows the reader to note decisions made by each developer and to compare the benefits of these approaches with those of the model proposedin this paper. 3.1 Researchin communication One type of attempt to automate office communications is to provide form basedmessaging[16, 17,44,45, 491. These sytans provide many of the benefits we are looking for. Specifically, system design is simplified through form basedmessagesand, typically, form based processinglanguages. The difftcuhy is that each form is created and processedindependently. Pew generalizations are possible and few opportunities for reuse of co& exists. Systemsusing semi-structuredcommunication such as The Coordinator [12,46] and Information Lens [26] provide some of the benefits desired (consider also [9, 381). For example, these systemsclassify messages,malting it easierto developrules to pmcess these messages. These languagescannot be used for present purposes hecause their languageswere not designedto carry the whole information content of the message. This is not appropriate for applications such as EDI. Researchershave created computational methods for natural language processing [15, 331. These provide general methods for interpreting “messages”(sentences) and an expressivegrammar (a subset of English grammar) for representing the “messages.” The difficulty is that many sentencescan be interpreted in multiple ways. Again, this would not be appropriate for many applications. 333
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Proceedingsof the 28th Annual Hawaii International Conferenceon System Sciences - 1995
The above obfifxvations aRect our communication model in the following ways. It is not clear whether the comm~ation model shotrId be w on inference or decodiug. Inhence is the basis for a mom powerful systembutitcanbediffkultto tzonsmct. The interplay ofinkencerulesalsomakesitdi8kulttopredictwhnta system will do in rwpcmse to any given message. Inf&entialsystemsdonu&eiteusiertotakeintoaccount the context of a message. Decoding systemslend themselves to clear communication but grow to be prohibitively large for non-triviaI systems. Decoding simplifies themappingIkomthemessagereceivedtoappro@m action. Since both types of system provide benefits and drawbacks,some aunt&a&ion of the two might be beneficial. Combining the two might mean that inference is usedinonepartofthemessageanddecodingisusedon another. Inanycasethereisnoclearchoiceforageneral messagewon system. Austh [2] opened a whole field of study with his descripkn of speechact theory (SAT). He proposedthat to say tmmthing is also to do smetbing. Further, Austin Praposl3d@atut@== can be classified by what they do. Hecalledthetypesofactsthatcanbeperfonnedin speaking illocutionary acts. A short explanation is in order. If a speakersays “It will rain,‘” then typically the spfxtktx is predicting that it will rain. The proposition is that it will rain and the titude is that of 8),prediction. If a spmker says *‘Will it rain? Ihen typically the speakeris asking whether it will m&n. In this case, the proposition is the same-&x? it wll r&-and the attitude expressed is that of a question. ‘Ibus, different attitudes can be expressedtoward the same proposition. SA theorists call these attitudes illocutionary forces. Sumrnarizing this core idea: every SA has the structure F(P), where F, the illocutionary foace,is applied to P, the propositional content of the act. l’%is is c&d the F(P) framework. SA theaists also propose that the small number of illocutionary forces can be categorized. This classification schemeis one of the main differences among versions of SAT [2,3,5,41]. The hierarchy of forces encouragesthe computer scientist to think about implementing these messageswith an object-oriented (00) system that encouragesinheritance of features. What we would like to do is send a message(an illocutionary ac:t, in this case) to an object and have it respond gcordingly. A significant problem with this implementation schemefor this system is that illocutionary acts can be iterated in utterances. Moore [30] found messageswith iterated illocutionary forces in commercial communication standards. An utterance can be (2)
which is of the form F(P), where F is a request and P is x. ThiswouldbeimplementedinanOOsystemas (3) X->reqwst(S, Ht) which presentsno problems, However, a messagewith iteratedillocutionary forces such as (4)
S request to H1 that Ht eesert to H2 that Y,
which is of the form Ft (F@‘)), are not easily implemented in an 00 system. The above analysis implies that all that is necessaryto respond to an utterance is to know the illocutionary act. This is not necessarilythe case. The systemmight have the following rule defined for an assertion:
~1
This rule checks that the messageis an assertion,extracts the hearer and propositional content from the message, and then adds the propositional content to the hearer’s database. Thisseemstobea~lerulebasedon our understanding of assertions:When someonetells us something, we try to remember it. Unfortunately, this is not exactly correct. Just becausea hearer recognizesthat the speakeris assertingsomething does not mean that the hearer is going to believe it. This is the difference between the illocutionary act and the perlocutionary act& recognition by the hearer of the act performed by the speaker and the effects the utterance has on the hearer. Other factors, including the propositional content and the utterance’s context, determine which perlocutionary effects are actually achieved. To illustrate this point, consider the following example. The default responseto an assertionis the definition as given in Figure 3. The use of this as a default fits better with our understandingof the process. We expect this process to be used unless something is extraordinary. Supposean assertionarrives (5)
barney assert to betty that on(low(inventory(x)), 6/2/94)
(i.e., that “bamey tells bctty that on 6/2/94 the inventory of x is low”), then we might add this to the databaseand then do something about it (e.g., order some more x). Further, supposethe following assertionis received: (6)
fred assert to betty that on(low(lnventory(x)), 6/2/94).
The hearer might have previously received false assertions from fkd so she neither adds this information to the databasenor does anything else about it.
S’request to Ht that X 334
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Proceedingsof the 28th Annual Hawaii International Conferenceon SystemSciences- 1995
sm~cturehas peat expressivecapability. In addition for increasedflexibility indirect representationis allowed for the messages. Thus, one application can send a request messagethat the recipient interprets as an order message. This gives great flexibility to the application developers but it also makes developmentmuch more dif-
Otherresearchershavenotedsomeofthebenefttsof
SAT and created hquages based on it. Woo 1471defined a language celled SACT that has the structure defined in Figure 4 (interpretation of the definition’s format is in Appendix A). The categories(his name for the illocutionary attih) am idaped from Se&e’s work.
fhlt.
Flpn 4 (twn 47, p. O @ 1. ::== narns of a variable, a table, or a
The following simple example shows how FLBC representsthe messagedefined in message(2): (8)
column of a table 4.)
to
Indicates tbat this messageis correcting the information in .
As the tpewh act theorists have pointed out, recognition of a message’spurposedoesnot imply that alI the effects the speakerdesired to take effect will, in fact, take effect. This is the difference betweenillocutionary effects and perlocutionary effects. ‘Ihe perlocutionary effects depend on context of the messageand how it is used. This works against our goal of making the messagehandlers as general as possible. I have proposedthat SAT and illocutionary acts might provide one way of generalizing the messageinterpretation mechanism. This generalization is limited by the need to account for perlocutionsry effects. Finally, discourse modeling provide a structured method of monitoring and, possibly, automating a conversation. Petri nets seem to be powerful enough to model even general processes. This indicates that they should be powerful enough for conversations. Some discoursetheories even xcount for interruptions in the conversations. Thesemight help overcomethe difficulties of trying to plan for every contingency in a discourseplan.
4.1 The bnguage The FLBC outlined in Figure 6 and described at the end of 53.1 is the basis for the language to be used. This language is expressive and allows new messagesto be defined without changing the grammar. It also has a means for representing the context in the message. Applications that use this language to communicate are not required to share the same workspacesince the relevant parts of the workspacecan be sent in the term. In order to use the PLBC the changesin Table 1 must be made. This languageusesthe F (P 1 framework and explicitly representsthe illocutionary force of the message. This encouragesdevelopers to create a reusable handler for each force. The f lbc ( 1 term allows the language to be used in two ways. First, it can literally represent the meaning of the message. Inferencescan be drawn based on the force, content, and context but the force must stay the same. This makes interpretation of the messages simpler. Second,the messagecan be the basis for an inferential process that may end up determining that the force representedin the messageis not the force actually accomplished by a message. For example, a request to xmaybeinterpretedas anon-literal prohibition to not do x. This is a more flexible schemebut is not appropriatefor many situations. The term newconv should be included in the context if the current messagebegins a new conversation. The
4.0 A communication framework for applications In this section I provide the details of the communication framework for applications. This framework includes the ccunmunication language, the method for processing messages, vocabulary representation, and discourserepresentation.
337 Proceedings of the 28th Hawaii International Conference on System Sciences (HICSS '95) 1060-3425/95 $10.00 © 1995 IEEE
Proceedingsof the 28th Annual Hawaii International Conferenceon SystemSciences- 1995 convltack
( ) teHn contains a list of the current umveX-
goals of the applications that necessitatethe sending of messages,and requeststhat other applications have not fulfilled.
sationidentifiers. The current focus of the conversation is the first term of the list. Older, suspendedconversations make up the remainder of the list. The final three tems have been added to allow for bettermanagementofthediscourse~ess. Latefsections provide more details about these?erms.
43 Discourserepresentation I propose that Petri nets be used to representthe normative discourseplans of each conversant. That it can do it is non-controversial-Petri nets with inhibitor arcs are Turing machine equivalent [34, p. 2011. Other choices are feasible and potentially superior; however, Petri nets are a common tool in the discoursemodeling literature so they will be used here. What is useful is that in this implementation actual discourse is allowed to deviate from this plan. This is done by incorporating terms in the message’s context term that signal the recipient that the current message is related in some particular way to other messages. Four terms are necessary to model subdialogs that researchers have identified (see $3.2). Intarruption( ) indicates that a new dialog should temporarily becomethe focus. When interrupting a conversation,a new conversationidentifier term. is added at the beginning of the convStaak()
4.2 Interpretingmessages Each illocutionary force has a default handler. Each messagereceived will be handled by the appropriatehandler. Figure 7 shows some example messagehandlers. These are not the only messagehandlers that can be defmed for these illocutionary forces. Over time they will evolve and become more sophisticated, just as people learn to use languagein a more sophisticatedmanner. The example message handlers attribute no particular structure to the lcnowl&e base of the underlying application. When the apptic&on is to updbtethe knowledge base (updQteltBO), the knowledge base can be either monotonic or non-monotonic. The application, not the communication framework, is responsiblefor extracting nformation from the knowledge base.
RespondingToO (already in the hIQW@) indicates that this messageis part of a sequenceof messages.This
Figure 7 A sample of the set of marsage handlers
corresponds
coordination type. messageis elaborating on a point made in a previous message. correction ( ) indicates that the messagesomehowcorrects a previous messagein the conversation.
procThis(msg(flbc(3, norm, literal), From, To, assert, Prop, Ctxt, ID)) :updateKB(From, is, Prop, rnsg(lD)), updateKB(To, Is, Prop, msg(lD)). procThiis(msg(flbc(3, norm, literal), From, To, inform, Prop, Ctxl, ID)) :updateKB(From, is, not@elieve(To, is, Prop)), msWh updateKB(From, is, Prop, msg(ID)), updateKB(To, is, Prop, msg(l0)). procThis(msg(flbc(3, norm, literal), From, To, confirm, Prop, Ctxt, ID)) :updateKB(From, is, confirm(Prop), msg(lD)), updateKB(To, Is, conflrm(Prop), msg(lD)). procThis(msg(flbc(3, norm, literal), From, To, retract, Prop, CM, ID)) :removeFromKEI(FroNm,is, Prop, msg(lD)), removeFromKB(To, is, Prop, msg(lD)). procThis(msg(flbc(3, norm, literal), From, To, request, Prop, CM, ID)) :getAnswer(Prop, Ans), sendMsgJTo, From, inform, Ans, [respondingTo(lD
Subordination0
to
Polanyi’s
indicates tbtthe
Flgure 8 Monltorlng the msssaga log monitorMsgLog(User) :msgLog(User, MsglD, no), msgSeen(MsglD), retrMsg(MsglD, kg), procThis(Msg), getMsgCtxt(MsglD, Ctxt), doesInclude(respondingTo(OrigMsgID), itHappened(recMsg(Who, J respondTo(OrlgMsglD), MsglD)), fail.
Ctxt),
monitorMsgLog( ) :- !.
Figure 8 shows what an application does to monitor the incoming messageslog. It looks for vd messageids (MegID) for User. It then marks the message as having been seen and retrieves the message. It then processesthe messagewith the messagehandlers (samples defined in Figure 7). If the messagecontext indicates that this messageis a response to a previous message,then it continues the execution of this plan by announcing that itRappened0. If my other type of messageis received, then an unfiished plan is not in-
Applications use this framework at some cost. Each application is required to implement a knowledge ~XW to store and retrieve information. This knowledge base should store messages sent and received, information other applications send it, the context of each message, 338
Proceedings of the 28th Hawaii International Conference on System Sciences (HICSS '95) 1060-3425/95 $10.00 © 1995 IEEE
Proceedings of the28th Annual Hawaii International Conferenceon SystemSciences- 1995
voked Thus, a plan can be used to direct a conversation (or other series of actions) but messagesare allowed to dl3VitWfnwnthph The structured representationin Figure 9 can be integrated into the voabdwy. (By n=ess&, this language is quite simihu to the PN language d&red in [22. p. 1031.) A plur. ( ) can be incorporatedinto context terms. This allows conversrunltsto discuss plans, create new plans, em.
The main benefit of such a framework is its flexibility. Toolsdevo~foritcanbeusedacrossawCderangeof application types. Only preliminary results have been ohservedbut them have heen positive. Mow [23] and Moore & Kimbrough [29] have M that formbased applications-both office automation and electronic data interchange-are easily implemented within a subset of this framework. ‘Ilrey demonstrated that forms containing other forms can also be accomodatedby this language. This framework also subsumes semi-structured communication systemsand those basedon simpler language structures. Semi-structured communication can be handled by this framework by defining the following term:
:Igwe Q Fetrl not repreeentatton 1. ::a= “ptan(” cplan-id> “, ” drans-list> “, ” cplace-list> “) 2. brans-list> ::SP “transL(r [ { ‘, ” } ] “I) 3. ::== “placeL(” [ { *, ” ) ] “I) 4. ::== “trans(” drans-id> ‘, ” ctransdesc> ” ” “, ” “) 5. &coming> ::== 6. ::== epiaceconnect-list> 7. ::=a “r [ cplace-connect> 1 “, * ) ] “1 6. ::=P: “p(” “, ” cconnect-type> “)” 9. ::== “norm” 1“inhibitor” IO. ::t= “pOR([” corder-trans> { ‘, ” corder-trans> } ] 7) 13. ccholce-action> ::== “pChoice(” cquestdescz. “, r { ‘I, ” cd-trans> } ] “1)” 14. ::a= a process to be completed, a goal to be reached, an event to occur (any of which can be completed manually or automatically) 15. ::=e=“orderT(” 11II 1 16. ::== “descT(” drans-desc> “, ” &ans-id> ‘Y
(10) m(Header, text(arg1))
The Xiaader term can contain a list of the header information and the argument of the secondterm can contain the unprocessabletext information usually contained in the body of a semi-structuredmessage. Using one communication language and one framework is a clear break from current practice. The microcomputer market is moving toward a common, simple language for interapplication communication (in System 7 for the Apple Macintosh it is the AppleEvents listed in the AppleEvent Registry). Though a language has been specified, the interpretation of thesemessagesis given informally. Each developer is left to his or her own accord to implement the interpretation mechanism. I have argued that this is not enough-we need both a common language and a common interpretation mechanism. The benefits of the proposed structure should be clear by now. Having only one language to interpret and monitor should make it easier to monitor processes originating from disparate applications, departments,and organizations. This should also simplify the process of developing cooperative and communicative applications. These then lead to the substantial industrial-organization benefits describedin $1. This system is obviously not appropriate for all communication based applications. As Nagasundaram correctly points out [31], the style of a messageis sometimes as important as the substance-and the proposed system certainly does strip the style from the messages. I agree with his concession that these systems can be useful in certain contexts and with his call to action [3 1, p. 391: “‘Following a strategy similar to that adopted by the expert systemscommunity, researchersshould quickly identify specific MSS applications with high potemial rather than attempt to develop systems with general purpose capabilities. We will learn much more from the actual operation of specific systems than from theorizing about MSS in
5.0 Discussion I have presented a communication framework for applications. This framework is meant to provide a blueprint for designers of all types of communication based applications. Within this framework is a highly expressive language that can be used for literal or non-literal computer pmcessablemessaging, a basis for a reusable toolkit of handlers for processing these messages,and a system for representing discourse plans from which actual discoursecan deviate. 339
Proceedings of the 28th Hawaii International Conference on System Sciences (HICSS '95) 1060-3425/95 $10.00 © 1995 IEEE
Proceedingsof the 28th Annual Hawaii International Conferenceon SystemSciences- 1995
general,divmed from context. Such applications am likely to be fairly well stnlcm, of an operational nature, and involve, primwily, horizontal rather than verthd conmunication (i.e., within, ratser than aross, orgmdion hds).” (p. 39) This is the exciting prospact aheadof us.
Acknowkdgmmts Thanks to Chuck Wiley of SWIFCO (U.S.) Inc. fur providing information about the S.W.1F.T. standardsfor financisl trading. The author can be reached at
[email protected].
(Eile: HICSS9J.doc.)
Appendix A B-termAisdef&asB. - non-terminal symbol C. . “Xyz” - termhl symbol xyz. l AIB-AorB. l [Al - zero or one instanceof A. zero or more instancesof A. l (Al-
l
A;:==
l
43
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