The Design of DINE: A DIstributed NEgotiation Support Shell1 Miklós Bíró, Ede Bodroghy, Attila Bor, Elöd Knuth, László Kovács Computer and Automation Institute of the Hungarian Academy of Sciences H-1111 Budapest, XI. Kende u. 13-17. Hungary E-mail :
[email protected],
[email protected]
Abstract The paper discusses the integration of currently commercially available techniques and supporting tools for constructing a specialized groupware application namely a distributed negotiation support system. It presents the different aspects of the integration methods and analyzes the actual design of a DIstributed NEgotiation Support Shell (DINE). The DINE model supports simultaneous, multiple issue, independent, peer-to-peer negotiations. It allows the integration of existing negotiation support techniques which, as opposed to DINE, mostly focus on those scenarios where the negotiation issues are shared by all negotiators. The latter techniques will be used to support the independent peer-to-peer negotiations in DINE. Negotiators may in fact use any tool even without DINE, as long as it supports the same peerto-peer information sharing protocol. At the same time, DINE is a generalized multiple criteria decision making model where the alternatives to be ranked are compound subsets of negotiated offers. DINE naturally integrates asynchronous and synchronous communication facilities, intuitive judgement and deep knowledge based techniques. The initial implementation is based on the Microsoft Windows environment.
Keyword Codes: H.5.3; H.4.1; D.2.2 Keywords: Information Interfaces and Presentations, Group and Organization Interfaces; Information Systems Applications, Office Automation; Software Engineering, Tools and Techniques; 1Supported by OMFB 91-97-11-0005, OTKA grants #2571 and #2575.
1. INTRODUCTION Nowadays groupware research is a hot topic. There is a great interest in designing and building systems for Computer Supported Cooperative Work (CSCW). Currently available communication technologies make it viable to create distributed systems to support human activities among remote users. Our work is motivated by this interest and the potential application of commercially available tools and technologies in this field. Negotiation is a human activity in which the human partners having “strong disagreement about factual or value judgments” [Jelassi, Foroughi 1989] try to achieve consensus. In a distributed negotiation setting the negotiators act at possibly different spacetime coordinates usually connected by different communication services. In this paper we examine the problems of building a distributed system based on a computer network to support the distributed human negotiation activity. This approach tries to integrate available tools to create support for this process. The suggested approach is a Distributed Negotiation Support System which is a special class of Group Decision Support Systems (GDSS). In this paper we don’t focus on the procedures of the negotiation but the integration of currently, commercially available techniques and tools to support this distributed decision making process (the negotiation). We discuss the services of the software tools that can be used to implement the system and how the integration can be performed. As a result of this approach the designed negotiation support system is a DIstributed NEgotiation Support Shell (DINE) which can be controlled by a higher layer system (discussed later) or a human end-user implementing the different (supported) scenarios of the negotiation process (human protocols). DINE is intended to support distributed negotiation processes which can fit into the following scenario or any of its specializations. The scenario is defined using an objectoriented approach where first the types of entities involved in the process are identified followed by their possible characteristics and the actions they perform. The entities and their representations are described in a general form, but with the features of the Microsoft Windows operating environment in mind as a consequence of the fact that MS-Windows is the environment for the first prototype implementation. The synchronous information sharing protocol is an extension of the Dynamic Data Exchange (DDE) protocol to networks [Biró, Böszörményi, Gyepesi, Kovács, Knuth, Szabó 1991]. A more general form of the network extension of DDE or OLE (Object Linking and Embedding) is likely to be included in the future NT (New Technology) release of Microsoft Windows. Allusions are made to the Hewlett-Packard NewWave implementation, where object orientation is raised to a higher level. The spreadsheet system used by DINE is “Microsoft Excel for Windows” which has both facilities for cooperation with NewWave and implementation for the Apple Macintosh. This latter fact is important since the system is planned to be implemented for a heterogeneous computer environment as well. The issue of the integration of asynchronous and synchronous communication requirements, and of intuitive judgement and deep knowledge based techniques is discussed in the last section.
2. ENTITY TYPES AND BASIC SCENARIO The following is a list of the fundamental entity types involved in the distributed negotiation process supported by DINE: • negotiating partners (partners, users, participants, or negotiators), • negotiation issues, • offers related to issues, • subjective and objective criteria including goals, requirements and limitations. The basic scenario involves participants who conduct negotiations with a set of typically independent partners over a set of issues. The discussions are based on synchronously or asynchronously made and modified offers. Each participant has his own system of criteria which are typically not shared. The significance of the word "typically" should not be neglected. The assumption that partners are typically independent does not exclude that they form coalitions with respect to some issues. If the fact of such a coalition becomes public then outside negotiators may consider them together as a single partner with respect to the specific issue. In this way, the overall set of partners can again be considered independent. Nevertheless, the case of secret coalitions cannot be excluded. The assumption that information is typically not shared does not mean that negotiating partners cannot decide sharing them. This may even become a highly sensitive issue if the negotiation environment is legally regulated (e.g information disclosure requirements, insider trading prohibition in a stock exchange). In fact, the negotiation or individual decision support systems used by different negotiators can even be different. The only requirement is that all of them support the same peer-to-peer information sharing protocol. Those who use DINE will be better supported in handling the multiple issue negotiation process with simultaneous independent partners. Existing negotiation support ideas and techniques, as opposed to DINE, mostly focus on scenarios where the negotiation issues are shared by all negotiators. On the other hand, the DINE shell allows the incorporation of these ideas and techniques for supporting the independent peer-to-peer negotiations [Gupta 1989], [Jarke,Jelassi,Shakun 1987], [Jelassi,Foroughi 1989], [Matwin, Szpakowicz, Koperczak, Kersten, Michalowski 1989].
3. ENTITIES AND THEIR REPRESENTATIONS Appropriate representations have an increased importance during synchronous negotiations, since the partners must be able to quickly digest and react to new information.
One of the principles in DINE is that a set of entities of the same type can either be viewed as a hierarchically structured list or as a set of graphical entities (e.g. windows, icons, bars in a simple chart or a Gantt chart). The advantage of a list is that it is concise and its elements can be transparently loaded from a data base in a practically unlimited number. The advantage of a graphical representation is expressiveness. The most appropriate representation depends on the current stage of the decision making process and the individual preferences of the user. DINE has two basic MDI (Multiple Document Interface) standard style windows. The first is the Partner Manager, the second is the Offer Manager window. The documents (or folders in the forthcoming NewWave version) contain sets of entities in either list or graphical form which can be switched over by executing a command from the menu of the MDI window. The facility of accessing the documents themselves in either list or window entity form is already built into MDI.
Figure 1. The DINE Shell
3.1. Partner Manager Partner Manager always contains at least one document window called Own. Separate document windows can be generated for each of the negotiating partners or a subset of negotiating partners determined by selection criteria. The Own document contains the set of all issues the user is negotiating. The issues contain parameters whose values are the subjects of the negotiations. New offer entities are generated from the issues by fixing the parameters and dragging the corresponding new graphical object to a partner or partner subset document window (or folder in NewWave).
This action results in the automatic mailing2 of the offer to the corresponding partner or to all partners satisfying the partner subset criteria. A dynamic link is preserved between an issue and the corresponding offers which is visualized by simultaneous highlighting on request (double clicking or menu selection). The vehicles for issues and offers can be simple texts, spreadsheets or even spreadstructures [Biró,Maros 1991]. (An independent realization of the spreadstructure idea is Borland ObjectVision for Windows.) A synchronous link can be established on request (menu selection) between the copies of an offer on several partners’ displays so that they can dynamically follow any modifications made by any one of them.
3.2. Offer Manager Partner Manager handles the communication between partners and the negotiation dependent dynamic modification of offers. In contrast to Partner Manager, Offer Manager provides specific support for the individual negotiator in the assessment of the effect of the acceptance of specific offers on his own system of goals, requirements and limitations. There is typically a large number of offers simultaneously negotiated by an individual. Not knowing their final outcome, he may want to keep more offers alive than his available resources allow to satisfy. This makes of course sense only for offers which are not binding. In case of binding offers, Offer Manager provides support for the tracking of the validity deadlines by signaling their approach (possible use of Agent in NewWave) and displaying Gantt chart representations. We are considering the application of Microsoft Project for Windows for this purpose. Considering both binding and non-binding offers, the negotiator must have a clear view of those feasible subsets of offers the elements of which can be simultaneously satisfied taking into account all requirements and limitations. The construction of the potential subsets can be performed either manually using intuition, or by making use of shallow or deep knowledge based techniques [Biró, Maros 1991]. The question of the possible techniques will be discussed in a forthcoming section. A subset of offers is represented by a document window inside the Offer Manager MDI window (or a folder in NewWave). The icons of offers are placed into the subset windows by either manual dragging or automatic invocation. Specific parameters of these offers 3 are dynamically linked to corresponding cells of a spreadsheet which automatically calculates totals of resource utilizations and levels of requirement satisfactions pertaining to the given subset. The calculated values can be visualized by charts which dynamically show any changes resulting from the inclusion or exclusion of offers. The negotiator can be alerted about any anomalies like resource overutilization within a subset. It is presumable that the above facilities will stimulate the construction of numerous feasible subsets of offers. An offer can of course appear in several of the subsets. DINE supports the management of these subsets by always keeping them in a list whose ordering is determined by multiple criteria ranking. Any of the known multiple criteria decision making (MCDM) techniques is appropriate for this purpose [Angehrn 1990], [Biró,Csáki,Vermes 1991], [Brans, Vincke, Marechal 1986], [Keeney,Raiffa 1976], 2Supposing
asynchronous communication service. 3 As cells in a spreadsheet.
[Roy,Vincke 1981], [Saaty 1980]. This is the point where multiple non-quantifiable or subjective criteria can be best made prevail. It is the interest of the user to conduct the negotiations in such a way that the offers in a subset with highest ranking become accepted. New subsets, containing old offers among others, can be constructed and merged into the ranked list at any time. An extreme case of interest for a subset is the one consisting of a single element. Offer Manager can be used in this way for ranking a set of simple alternatives which is the original purpose of MCDM methods. The Offer Manager approach is by consequent a generalization of MCDM techniques.
4. INTEGRATION OF VARIOUS TOOLS A structured overview of negotiation theories and their influence on existing systems is presented in [Jelassi,Foroughi 1989]. Some related design issues of DINE are discussed below.
4.1. Asynchronous and synchronous communication The nature of the possible cooperation of the negotiators (the human protocols) can depend on the availability of the different communication media. The negotiators can interact synchronously or asynchronously. Synchronous interaction presumes the simultaneous presence of the negotiators at different locations. The asynchronous interaction is supported by the presence of a communication system having information store-and-forward capability4. In the latter case the simultaneous presence of remote users is not required but it is not excluded. In DINE both forms of cooperation are supported. Offers are generated from issues and they are sent out to the interested partners for inspection and possible modification according to their own system of goals, requirements and limitations. This communication is typically asynchronous, since the partners do not have to work together. The offers are packed into e-mails and sent to the partners. Appropriate tools are required which allow the monitoring of the state of the offers. The state of an offer can be one of the following: {sent_out, delivered, lost, refused}. The offer monitoring tool memorizes the timestamps of emission of the offers. The return reply mechanism of e-mail systems is used to inform the sender about the delivery of the offer. If the return reply did not arrive within the predefined timeout period the offer monitor tool considers the offer being lost and informs the higher layer5 about this fact. The higher layer has to arrange for further recovery. The receiver negotiator can selectively refuse any offers from particular sources. This prebuilt mechanism is not considered as a part of the higher layer6 protocol. After the private inspection of an offer, a negotiator may want to establish synchronous 4 Usually electronic mail. 5 E.g. Human user. 6 Human protocol.
contact with his partner so that they can more efficiently discuss the issue. If the offer is represented on a spreadsheet model, they may want to share it and use additional private sheets possibly linked to the shared one for an immediate assessment of the consequences of any modifications. Alternatively, there may be specific cells on a single spreadsheet which are shared by different partners. The protocol necessary for this purpose has already been mentioned. If the synchronous contact is not necessary or possible then the reply is sent back via an asynchronous communication medium (usu. e-mail). The reply can be a complete spreadsheet containing the modified offer or the elementary modifications referring to the original spreadsheet. In both cases the offer monitoring tool is responsible to enforce the modifications in the original offer. Here a version control mechanism establishes check points for logging purposes saving the original values of the offer. After this action, the entire elementary circle of the peer-to-peer negotiation process is completed. Using this elementary circle as building block, one can create a more complex structured negotiation process. The methods and tools for the creation of this complex negotiation process are described in the following section of this paper. In the prototype implementation the commercially available cc:Mail electronic mail system is our first choice for our purpose since it is implemented for Microsoft Windows, the Apple Macintosh and a number of other environments as well.
4.2. Sructured negotiation Beyond the previously described elementary negotiation circle higher layer negotiation structures are necessary to control the overall distributed negotiation process. These higher layer negotiation structures prescribe the routine cooperation procedures among the remote users. A balance is necessary between the unstructured communication (which gives a significant amount of freedom for the negotiators) and the completely prescriptive communication process. The different CSCW systems can be classified according to the forms of the control used in the system [Rodden, Blair 91]. In the case of the explicit control actual representations of the control procedures are offered by the system. Via these representations one can view and tailor the interaction procedures. If the system doesn’t offer explicit control then available cooperation styles define the interactions among the users (implicit control). The DINE model constitutes a compromise between these extremities. The actual implementation allows both types of control. The shell offers the basic cooperation structure which can be controlled explicitly with e.g. scripts or office procedures (procedural language) or simply directly by the human users.
4.3. Deep knowledge tools and intuition Feasible subsets of offers have to be constructed in Offer Manager so that the negotiator can clearly see the resource utilizations and the levels of requirement satisfactions. This task can clearly be performed manually by making use of human intuition and dynamic graphical
aids. A more sophisticated and well suited approach is the use of deep knowledge techniques. For example, mathematical programming models can easily take into account quantifiable requirements, resource limitations and even optimize for an objective function. In addition to assembling optimal subsets of offers, these models can also be used to generate alternative offers resulting from minor modifications of model parameters or from postoptimality analysis [Biró,Maros 1991]. The goal programming approach developed in [Kersten,Szapiro 1986] is an outstanding potential negotiation support tool belonging to this category. A startup library of mathematical programming models can be supplied with DINE. These models will be embedded into a Microsoft Excel spreadsheet and customized commands will be provided for their final specification and solution.
Figure 2. Microsoft Excel spreadsheet with synchronous communication links It is inevitable on the long run that the construction of new models become necessary by the users themselves. This will generate a demand for model building tools which has already been a fruitful research area lately [Binbasioglu, Jarke 1986], [Biró,Maros 1991], [Geoffrion 1987], [Gerlach,Kuo 1990], [Ma,MurpyStohr 1989], [Murphy,Stohr 1986], [Müller–Merbach 1983], [Roy,Lasdon, Plane 1989]. The inherent dangers of end-user model building should not be neglected [Gass 1990]. The combination of the use of deep knowledge tools, intuition, and transparent spreadsheet representations in the DINE approach can however contribute to the lessening of these
dangers.
4.4. Objective data and their overriding Database management, as the only means of accessing and maintaining accurate and consistent data, has long been recognized as one of the key components of decision support systems [Sprague,Carlson 1982]. In the DINE shell however, the possibility of overriding these data is equally important for testing the consequences of compromises. Borland ObjectVision for Windows provides support for both database management and data overriding. Pioneer Software’s Q+E for Windows can be easily integrated with Microsoft Excel and gives access to numerous data base systems.
5. CONCLUSION Ideas leading to the development of a distributed negotiation support shell have been presented. The description concentrated on a Microsoft Windows based implementation. Besides having tremendous success on the market, MS-Windows provides great flexibility as far as the simultaneous use of custom and commercial software is concerned. The ideas take maximum advantage of these features by incorporating several popular and recently released commercial tools while allowing the use of existing bilateral negotiation support methodologies, multicriteria decision making techniques and deep knowledge approaches.
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