Proceedings of the 38th Hawaii International Conference on System Sciences - 2005
A Practical Web-based NSS Framework for E-Business Negotiation Wei Shang, Yijun Li, Wenjun Sun School of Management, Harbin Institute of Technology
[email protected],
[email protected],
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Abstract As a requisite to the complete e-business revolution, Negotiation Support System (NSS) today hasn’t been widely adopted in real e-Business negotiation practices, despite years of research on it. On the basis of our former work on NSS, this paper focuses on the implementation of theories, models and technologies into practice. The web-based negotiation support framework presented in this paper is practical, in that: a) different negotiation protocols can be adopted; b) business negotiations can be supported dynamically according to participants’ settings; c) the framework offers easy-to-maintain business logic and decision models; d) the system may be hopefully integrated into corporate information systems. A common negotiation protocol is designed; and a linear negotiation mediation models is given. An implementation that enables the outstanding features of this framework is discussed as well.
1. Introduction Computer hardware and software have been evolving in an amazing speed, and so have the information technology and the Internet. This has caused drastically changes in business practices and life styles. E-Negotiation, the well-known international tournament, offers an opportunity for students and researchers to conduct electronic negotiations using several cutting-edge negotiation tools [1]. The idea of negotiating online with software support is more feasible than before in every walk of life, especially in the well-developed global e-Business environment. Negotiation theory and tactics have been discussed from various perspectives [2, 3, 4, 5]. In the Internet age, more and more businesses are conducted online, and e-Business negotiation becomes a popular topic. E-Business negotiation can be defined as different parties conducting business negotiation electronically via the Internet. Thorough understanding on decision theory, information technology and business negotiation processes are needed to develop a practical information system to support e-Business negotiations. We designed and developed a web-based Negotiation Support System (WNSS) for e-Business Negotiation two years ago. Several companies have tested this system and given us some useful feedbacks. According to these feedbacks, we have reconsidered the requirements of NSS in e-Business transactions and will introduce a WNSS
framework in this paper to make NSS more practical for e-Business use. Fundamentals on NSS and the practical features of Web-based NSS are discussed in the first part of the paper. With a general idea on the architecture of WNSS, negotiation protocols and two negotiation mediation support models are presented. The implementation of the WNSS framework and future directions are discussed at the end of the paper.
2. Fundamentals on NSS NSS is a man-machine interaction system, in which operation theory, game theory, decision theory, behavior science, computer technology, information technology and man-machine engineering are applied to help the negotiator to analyze and solve the negotiation problem. [6] The mission and means of NSS were mentioned by Bui [7]. “NSS is designed to assist negotiators in reaching mutually satisfactory decisions by providing a means of communication and thorough analysis of available information.” NSS has evolved from decision support system in the very beginning and focused on conflict resolution among the decision makers. NSS appeared as stand-alone software in the early years [8, 9, 10]. With the development of information and communication technology, web-based NSS emerged in researches, such as the work of Stanley [11] and Daniel Druckman [12]. Today, practical use of NSS, especially in e-Business, is widely discussed and gradually put into real business (Inspire [13], Negoisst [14], etc.). Research on theoretical aspects of NSS includes: negotiation problem presentation, negotiation protocol, negotiation strategy, negotiation conflict resolution and so on. Negotiation presentation is responsible for defining the articles of a negotiation and the measurements of the articles and the solution. Negotiation protocol is a series of descriptions on how the negotiation is conducted, and appears as a set of rules about the interaction manners among the negotiators. Negotiation strategy is a proposal sequence by which a negotiator is trying to get the most from the negotiation. In a certain negotiation context, the final result of the negotiation is decided by the strategies taken by all the participants. Conflict resolution is the main problem for NSS to solve. According to each participant’s proposal and preferences, the NSS is responsible for offering a solution that satisfies all participants, and therefore facilitates an agreement.
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3. Requirements of a WNSS framework When an information technology becomes widely accepted and is ready to be put into real business use, certain kind of specifications or frameworks always appears correspondingly. This kind of specifications or frameworks may offer an infrastructure to the developers to transform the new technology into practical applications efficiently and effectively. Therefore, we introduced the concept of WNSS framework, which provides basic implementation and powerful extensibility to WNSS development.
3.1. Basic features of WNSS for B2B transactions Negotiation is a part of the traditional business transactions. Each side of the deal will prepare the negotiation by investigating the information of both the transaction itself and the other side(s). According to their information and knowledge, negotiators will choose some strategies to negotiate with others and reach a mutual agreement if possible. After all the parties have reached an agreement, a contract is required to be subscribed to guarantee the rights and responsibilities. In e-Business transactions, especially in B2B transactions, e-Business negotiation is expected to be something more powerful than the traditional negotiation. Due to the characteristics of the Internet and the development of computing capability, an e-Business negotiation may run through different parties beyond the geographic restriction with efficient communication, and conflicts of interest may be resolved with the aid of decision support software or negotiation support agents. When we let some local enterprises to test our former WNSS, we managed to get some useful idea from the end-user. From the perspective of the business end-user, e-Business negotiation requires the following basic functions: a. Identifying the authorization and credit level of a partner. b. Querying the transaction information and partner information. c. Defining a specific negotiation session according to a certain transaction with a certain partner. d. Negotiating the transaction detail with the other side(s). e. Building contract by choosing a contract model and making some modifications. To enhance the performance of eBusiness negotiation, the following functions are preferable: f. Communicating efficiently with the partner. g. Seeking help from the system to resolve the conflict between both sides.
h. Exchanging media files or documents during the negotiation. Considering the requirements of the eBusiness negotiation, the WNSS should be designed to be sufficient enough for the negotiation to proceed online. The WNSS may firstly match the enterprise with several potential partners, according to what the enterprises claim they need or offer. Then the virtual negotiation room is built and rules of the negotiating process are determined. After that, the negotiation begins and clauses of the agreement are defined respectively in detail. Both sides may communicate with each other and share files and opinions. If they try to seek help from the system, the WNSS will offer a solution based on each side’s preference of the negotiating clause. Operation research, game theory, decision theory, behavior science and psychology are considered in designing the negotiation support section, which is the center-piece of WNSS, and will be discussed in detail in the following sections of this paper. Once the negotiators have reached an agreement, a contract will be created as the final step. Inspection of the negotiation session, query of the information and management of the contract are available to qualified users at any time.
3.2. Critical features from the managerial perspective Although the requirements we discussed above sound perfect to meet the negotiation needs of an eBusiness transaction theoretically, we found it to be far from the reality when we promoted our system based on these requirements to several companies for their eBusiness transactions. Most features offered by our former WNSS are acceptable and some of them are considered as critical features by the companies. And there are also some features the companies claimed critical are not included in our former WNSS. The critical features according to the companies’ trials can be summarized as the following four aspects. Firstly, the media-rich communication support feature seems to be the most important feature to the company users. Negotiation is quite important in B2B transaction and managers are used to face-to-face negotiation. Seeing the counter parties’ faces and listening to their comments make the managers feel that they have attached enough importance to the negotiation and they can use some of the traditional negotiation tactics in the electronic Negotiation too. Secondly, customization and user-friendliness also seem to be very important to the company user. The idea of NSS is to help the negotiators to structure their negotiation problem with information technology. But most negotiators tend to be a little confused facing the abstract model of negotiation problem, and they are
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reluctant to make any effort to understand the concepts of utilities and satisfactory degree as well. What they want is just a system customized to their own business perfectly and an user-friendly interface that they can operate with ease either to negotiate issue by issue or to negotiate the contract as a whole. Thirdly, all the companies claimed that they need cooperation and competition at the same time when they conduct an electronic negotiation. Although the mediation function provided by the WNSS has been proved to be useful, it seems not to be as attractive to the company as we thought. The negotiators want to make their own efforts to persuade others in order to gain more from the negotiation. Therefore, on one hand, the WNSS is required to offer a mediation mechanism to help negotiators to cooperate for mutual gain. On the other hand, the WNSS should offer a bargaining platform for them to compete for a better solution according to their own interests at same time. Finally, integration with the existing information system both inside and outside the company seems to be an important feature. The WNSS may be practical enough to play an indispensable role in the eBusiness only if it can be integrated into the whole eBusiness platform seamlessly. For instance, an international bidding project manager said they already had the contract management system and they would use the WNSS only if the WNSS was compatible with their existing system. Furthermore, integration between the enterprise information systems of different companies may enable effective and collaborative negotiation in supply chain, which is also a crucial feature influencing the practicability of WNSS.
Each negotiation task is assigned to a virtual negotiation room. Data generated during the negotiation, including the proposals and all the attached documents, is stored in this virtual room. Flexible and easy-to-do customization of the virtual negotiation room is a crucial feature of the virtual negotiation room. On one hand, the predefined settings of the room should be loaded according to the common negotiation tasks of an organization, so that the users can be relieved from the negotiation preparation routines. On the other hand, users need to adjust what information should be kept and how the negotiation should be performed in the virtual negotiation room at runtime.
Media-rich communication support
Multimedia Interaction (from WNSS)
Customization enabled architecture
Virtual Negotiation Room
Negotiation Task Management
(from WNSS)
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Negotiator Integration with outside IS
(from Actors)
Contract Management (from WNSS)
Contract Management System (from Existing inside IS)
Partner's Portal Integration with inside IS
(from Existing outside IS)
eMarket (from Existing outside IS)
3.3. Architecture of the WNSS framework
eCommerce Portal (from Existing inside IS)
In order to facilitate the practical use of WNSS in eBusiness, a WNSS framework is designed as shown in figure 1. Four packages are built to separate functions of WNSS and make the system well structured at the same time. The package of Virtual Negotiation Room is the core of the framework, and the other three packages are the boundary parts for better performance and enhanced practicability. The negotiation task management package is responsible for initiating a negotiation either by manual operations or by automatic negotiation requests sent by the company’s eCommerce portal. If information of the potential partners is available in a certain electronic market, the negotiation task management package may also try to match the counterpart(s) and collect both transaction information and partner information. And if a potential partner has a compatible portal for negotiation task access, the negotiation invitation of intent may be sent and considered automatically by the other side.
Figure 1. Global view of WNSS The multimedia interaction package offers multimedia communication channels as instant messaging, videoconference and media file exchanging, which can be a satisfactory means of media-rich communication support to the online negotiation activities. The contract management package deals with the composition and subscription of the contract, when an agreement is reached. The contract management package may also provide features to help the negotiation room to read from or write into the existing contract management system, if the enterprise information system already has the contract management module. This WNSS framework meets the requirements raised by the negotiation practioners. A customized WNSS can be built efficiently and effectively according to various negotiation requirements of different organizations. The design of the WNSS framework will be discussed in detail in the following part of the paper.
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DecisionSupport ProposalEvaluation
ConflictResolution
ProposalOffering
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Negotiator (from Actors)
ProtocolDefine
NegoRoomManagement NegoRoomInitiation
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brokerage solution. This kind of negotiation may succeed only when all the parties accept a proposal. We may design a mechanism where the proposal is passed from one party to another, and each party conducts the same way sequentially in the generic bargaining protocol (as shown in figure 4). Raiffa’s work [2] studied the negotiation problem from scientific perspectives in 1982. He divided the negotiation into: two parties-single problem, two parties-multiple problems, and multiple parties-multiple problems. The bargaining protocol introduced in his work has become the most commonly adopted model. The activity diagram of this protocol is shown in figure 3. According to this protocol, one party offers a proposal and the other party may respond by a) accept, b) refuse and exit or c) refuse but bargain. Considering the business negotiation context, we may extend the protocol to multi-party scenarios. negotiation initiator
negotiation participant
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Figure 2. Use case diagram of the virtual negotiation
room
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4. Negotiation protocol design Flexibility in conducting the negotiation processes for e-Business is a critical feature for the adoption of NSS in e-Business transactions. If a WNSS is compatible with different negotiation processes, it will surely be more practical than the NSS that supports only one protocol. We will study the business negotiation protocols and then design a common protocol to support various negotiation processes.
observing others' proposal
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4.1. Generic bargaining protocol negotiation initiator
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Figure 4. Multi-party sequential bargaining protocol
negotiation participant
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Figure 3. Generic bargaining protocol Firstly, we have the scenario of several parties equally discussing the same problem together. Think of the negotiation among banks to decide a uniform credit card
waiting for others' proposal
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Figure 5. Multi-party simultaneous bargaining protocol
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Secondly, we have the scenario where a party negotiates with two or more parties at the same time. This is commonly seen in the business occasion of multi-attribute auctions and reverse auctions. We may design a simultaneous model (as shown in figure 5), in which the negotiation initiator negotiates with the participants and there’s no need for participants to reach any agreement with each other. For the case of more complex problem, a combination of sequential protocol and simultaneous protocol may be an alternative to present the negotiation process. In this way a generic bargaining protocol can be designed.
4.2. Bargaining protocol with decision support We introduce negotiation situation analysis to the generic bargaining protocol to facilitate negotiators with decision support functions. Bargaining protocol with decision support can be inferred from our former discussion by adding a decision support state following the “observing other’s proposal model” in figure 3, 4 and 5. Process information should be stored and read in to support the decision. Preference setting and modification are also a necessary supplement to the protocol. Preference and utility functions are private to each negotiator. It’s not easy to design a model to analyze the situation in this bargaining protocol, since the decision theory and utility theory may not solve the problem without complete knowledge of the whole problem. Although the game theory of incomplete information game may solve the problem according to the Bayes rules, the solution with a form of probability is not practical for the negotiator to make decision. Another method to solve bargaining problem is to use artificial intelligence, such as expert system or machine learning theory. Due to the algorithm’s complexity and knowledge retrieval problems, the AI based method is also not acceptable in most cases. As Inspire (http://www.interneg.org/inspire), the well-known NSS software, has done, situation analysis can be done visually in a negotiation process graph [13]. This alternative is better than no support though.
4.3. System Mediated Protocol The nature of bargaining protocol places the negotiators on the complete opposite position and any revealing of the self preferences may cause the other side to find your weakness and take advantage of it. In the satisfaction based negotiation, each negotiator takes what he cares most, and makes concession on others’ preferences. This is only ideal in business negotiation practices. Profit is the first to consider in any transaction. Therefore the Pareto Optimization is hard to reach. As most NSS has considered, the system can perform as a mediator and collect information of each party but do
not reveal it to the opponent(s). The system, in this way, may have the complete knowledge and is able to give a relatively acceptable solution to resolve the conflict. Our former work WNSS [15] is built on this protocol (as shown in figure 6). This mechanism sounds theoretically perfect, but often could not reach any optimal solution in many practical negotiation situations. negotiation initiator
NSS
negotiation participant
start reading negotiation process
proposal offering
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set or modifiy preferences
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Figure 6. System mediated protocol
4.4. Common negotiation protocol Bargaining protocol represents the traditional way of negotiation, and the business users are more likely to use it instead of system mediated protocol. But the system-mediated protocol may resolve the negotiation conflict efficiently when the negotiators have different preferences on the negotiation articles. Therefore, we need a common framework to support both protocols to enable users to shift from one protocol to another dynamically. Considering the complexity of the protocols, we need to simplify it by identifying the limited states of the negotiator sharing by both protocols. Besides start and end states, there are four states in both protocols: waiting for others’ proposal, waiting for system solution, observing others’ proposal, and observing system solution.
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Expanding the alternatives has been widely considered as a means of resolving the conflict. When one party has added an alternative to the solution space, other parties should evaluate this newly introduced alternative to support their decision. Therefore, we add a state of having new alternative(s), and the negotiation state chart is shown as in figure 7. This common negotiation state transition can be treated as an infinite state machine without output, thus it’s easy to simulate it by means of computer programs. start negotiation initiator submit a proposal process store
waiting for others' proposal
negotiators submit their proposals
turn to direct bargaining
waiting for system solution
evaluating new alternative(s)
evaluating new alternative(s)
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having new alternative(s)
seek for system observing others' mediation proposal
process store
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Figure 7. Common negotiation state chart
5. Decision support design According to the previous discussions on the WNSS framework, two kinds of decision support request are raised. One is single side decision support, which deals with incomplete information from one side and gives constructive suggestions for more returns of this side. The other is mediation support, which needs complete information from each side to offer a mediated suggestion by reallocating the resources or optimizing the solution. Presentation of the negotiation problem as well as two practical mediation support models is discussed in the following part of this section.
5.1. Negotiation problem presentation Negotiation problem presentation can be various in different decision models. In order to make the WNSS framework practical and facilitate as many decision support models as possible, a business negotiation problem can be presented by two kinds of factors: issue factors and negotiator factors. The issue factors are the issues to be discussed between the negotiators, such as the price of the goods or the transportation means and so forth. Issue factors are always different in different negotiation and influence the final agreement directly. While the
negotiator factors are negotiators’ characters that impact the actions of the negotiators and ultimately impact the negotiation process. According to our previous research, the following negotiator factors have enough impact on the negotiation process: a) the preference vector on each issue, b) the satisfactory vector on each alternatives of a certain issue and c) the strategy of concession. To structuralize the information from multi-issue and multi-party business negotiation, we may consider the issue factors of a negotiation from different levels. Assume a) each negotiation may contain one or more contracts, and in one contract only two parties are involved, b) each contract contains several articles, and each article can be presented by a variable that can be assigned to a numerical value or enumerable value. In this way, a multi-party negotiation can be simplified by considering it as a combination of several bilateral negotiations with constraint among each other. Assuming that a negotiation problem can be presented as N={C0,…, CI-1, FC}. Ci presents contract(s) which is (are) going to be generated if there’s an overall agreement among the parties. FC={fcj(C0,…, CI-1), j=1…J} presents the set of constraint functions, in which j stands for the number of the constraint functions. There are usually several key articles in each contract. And these articles may be not of the same importance to the negotiator. Therefore, two kinds of knowledge should be presented at the contract level: article definition and article importance. The article definition should be the same to both sides, since each side will sign in the same contract in the end, if the final proposal is granted. Assuming the articles are independent from one another, negotiation contract i can be presented as a vector of key articles Ci={Ai,0, …, Ai,K-1}. The article importance is not necessarily the same to each side. Each side can define different importance levels. Therefore two vectors are needed to present the importance of each articles defined by each side. Let In be the importance vector of a negotiator n. The sum of every element of In should be 1. Assume a function uni,k(x*) is negotiator n’s mapping of article Ai,k’s value x* to its utility. To evaluate a proposal to Ci, the utility UnCi to a contract Ci of a negotiator n is expected to be: (1) UnCi=ě( Ini,khuni,k (x*) ), k = 1, 2,Ă, K And the total utility Un to a negotiation of the negotiator n is expected to be: (2) Un = ěUnCi, Ci = C0, C1,Ă, CI-1 In order to assign the article definition into variables, we use two variable types of numerical and enumerable to present the articles. Numerical variables may present which can be compared by value, like price, discount, or ratio of advance payment and so on. Enumerable variables may present articles which can not be compared by value and have to assign the satisfactory level to each
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possible value by negotiators, like delivery spot, goods quality, or some other that has discrete values. For a numerical variable, the utilities of its values are in direct proportion. The value in the proposal of one side has utility of 1. The value in the proposal of the other side has utility of 0, if the values from proposal of each side are not the same. Values between the two occasions mentioned above can be calculated easily by a linear mapping. For an enumerable variable, a negotiator must assign a utility to each variables, the maximum utility must be 1, to accord to the numerical variables. To simplify the utility assigning operation, we use a kind of AHP (analytic hierarchy process), in which the negotiators just describe the comparison of the importance between articles using vague adjectives such as less important, same, very important, and so on. And it’s the responsibility of the AHP function to convert these descriptions into utility value between 0 and 1. By this means, the utility function can be evaluated, and together with the formula (1), a negotiator’s utility of a given proposal on a contract can be calculated.
5.2. Linear mediation support model Business negotiation mediation is a complex task involving economic and psychological aspects. Generally, there are two objectives to achieve in a negotiation mediation model: maximizing the overall utilities and guaranteeing the fairness. These two objectives make the mediation model a multi-objective programming model. There are quite a few ways to solve a multi-objective optimization problem [16]. We introduce a simple but effective linear mediation model to simplify the problem. Suppose there are two negotiators negotiating for a transaction that contains articles of price, quantity, payment, and delivery time. The importance degree of each article to a party is defined as weight. The proposed value and assigned weight of each article are shown in table 1. Table 1. An example of bilateral negotiation Negotiator A Negotiator B Article Proposal Weight Proposal Weight Price 5000 60 4000 20 Quantity 100 30 50 20 Payment 100 5 0 30 Delivery 30 5 0 30 Time Points 90 60 gained The mediation support method for this bilateral negotiation has the following steps: a) For each key article, assign the value proposed by the party who allocates more weight to this article than the other party. In this example, we have price = 5000, quantity = 100, payment = 0 and delivery time = 0. If two
parties allocate same weight to an article, leave this article’s value unassigned. b) For each unassigned article, calculate the total points gained by each side, and assign the value proposed by the party who has less total points. If the two parties have the same points, randomly assign either value proposed by the two parties. c) If the two parties gain different points, select an article with smallest point ratio from those are assigned to the values proposed by the party gaining higher total points to adjust the value. In the example, negotiator A gains more points, and the price and quantity article are assigned the value proposed by A. Point ratio of price is 60/20=3, and point ratio of quantity is 30/20=1.5. Thus we select the article of quantity to adjust. d) To achieve the fairness objective, adjustment on the value of selected article can be done to minimize the difference between the points gained by each side. If the selected article has a numerical value, we may calculate the value by sliding scale. In the example, assume that we may adjust the quantity to x to make a fair deal. That is, this x will make the utilities of both parties equal. Assume the utility functions are linear (as shown in figure 8), we have (x-50)/(100-x)=A’B’/AB=(80-60)/(90-60), and consequently we get x = 70 and the point gained by each side is 72. If the selected article has an enumerable value, we may calculate the two sides’ total points on each alternative of this article and find the value that makes the minimum difference between the points gained by each side. Points A
90 80 72 60
B’
Solution
A’ B 50
x
100
Quantity
Figure 8. Linear mediation support model Consequently, the two parties get total points of 144. Although the total points are not maximal, the final solution guarantees the fairness, equal gaining of each side, which is found to be more important for company to accept the mediated solution mentally. In case that there are more than two parties involved, we may still adopt this method by assigning the value proposed by the party which consider it as the most important than any of the other parties to each key article to achieve maximization of total gaining, and adjusting the article with smallest point ratio among parties to achieve fairness. Accordingly, there will be more than two utility lines in Figure 9 in this occasion. The solution point will be the point has the least total distance to each
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design pattern is shown in Figure 9. In this implementation, when a HTTP request reaches the web server, the following events occur: The Negotiation Controller intercepts all requests from the users. y The Negotiation Controller analyzes the request path information to determine which Handler should handle this request. y The Negotiation Controller then calls the Handler Factory to get an instance of the Handler. y The Negotiation Controller calls the Handler to process the request. y The Handler represents the Model in MVC. It implements the business and data logic. Each Handler has very specific responsibilities. After processing the request, it combines multiple data beans (retrieved by calling the Persistence Manager) into a Page Bean, which later on is used for presentation purposes. y The Persistence Manager serves as a façade for classes (stateless session beans, for example) that are responsible for persisting and retrieving data through the JDBC API. This approach implements the rule of encapsulation in object oriented programming paradigm. y If any exceptions occur during the process above, the Handler will decide whether to generate error pages that are specially designed for displaying error messages. y The Handler passes the assembled Page Bean to the Controller.
utility line. The fair and utility-maximal solution exists theoretically, and the solution given by our model is just a proximate one. Further work is still needed to test how effective this solution is both theoretically and practically.
6. Implementation of the WNSS framework JAVA 2 Enterprise Edition (J2EE) is one of the most popular technologies used in EIS development because of its features, such as being platform-independent, object-oriented, component-based and multi-tier. We use J2EE technology to implement the WNSS framework.
6.1. Infrastructure based on the MVC design pattern
Figure 9. M-V-C design pattern of WNSS framework
The Model-View-Controller (MVC) [17] design pattern has been recognized as a powerful software design pattern that enforces the separation between the data, business logic, and presentation layers of an enterprise application. The WNSS framework adopts the MVC pattern. A typical J2EE implementation of the MVC clientBroswer
JSP
Presenter
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Handler
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request a page get handler
handle request get data beans get data create return data beans create
attach data beans
return page bean get presenter present present non-html/xml file present html/xml
Figure 10. Sequence diagram of WNSS framework processing mechanisms
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y
The Page Bean, which has been sent to the Negotiation Controller, contains a Presenter object to present the data. y The Negotiation Controller passes the user request and response parameters to the Presenter, and calls it to present the Page Bean. y The JSP page appointed in the Presenter only needs to get data from the Page Bean, convert it into a HTML page and send it back to the user. The sequence diagram for this process is shown in Figure 10.
between user IDs and corresponding request identities are stored in a database table, and can be maintained by the users who have certain special privileges. By subclassing the AuthenticatedRequestHandler or the AuthorizedRequestHandler, each handler has its own security level. The built-in rules of authentication and authorization release the module developer from the trifle work of authenticating and authorizing the user for every operation.
6.2. Persistence management
As a practical WNSS framework, three levels of customization are required: protocol customization, decision model customization, data source and operation interface customization. A state-action mapping object is assigned to each virtual negotiation room to decide how the negotiation can be conducted. Typical handlers that make the state of each negotiation transmitted to another are stored in the database, and if any of these handlers occurs, the state-action mapping will help to find the following handlers to decide what each party should do next. User who has the corresponding authorizations even during the negotiation processes can also alternate the state-action mapping. This enables the customization of negotiation protocols. All the negotiation entities related to the information presentations are designed as interfaces and basic implementation according to the given negotiation problem presentation is designed. In this way, new decision model can be added to this framework easily by implementing the interface of existing negotiation entities to enrich the information expression. And design models are indexed respectively according to their adoption in different protocol, so that negotiators may decide which decision model to use at run-time. Information of database connections is specified in a special type of configuration files (Java properties files to be specific). This kind of file may have its content changed without having to restart the whole application. Therefore, agile development on database connection management is implemented, which enables the WNSS to switch data source easily. And all the prompt messages and menu bar messages are specified in configuration files too. Different customization types group these messages configuration files, and users may customize the appearance of their WNSS either by locale or by any other personal preferences.
There are three kinds of entities in the WNSS framework: structural entities, negotiation entities, and decision entities. Structural entities include the negotiation problem description classes, such as state transition mapping, article definition and so on. Negotiation entities include the proposal histories and the basic information of a negotiation. Decision entities are the decision support models. Since an eBusiness negotiation can be conducted for several rounds, all these entities must be serialized and stored in persistent storage, as in databases or in files. Small data units representing all these entities are designed as Java classes. A persistent manager is a final class to manage the instances of those classes that interact with the databases to obtain and update small data units. This helps to encapsulate the database access by letting WNSS framework manage the lower level details of data exchange and ensure data transfer security and data consistency.
6.3. Authentication and Authorization User authentication and authorization is indispensable in the WNSS framework. Without authentication, a user can only access very limited information, for most of the negotiation data could be confidential. Authentication is not enough in the case where the initiator of a certain negotiation usually has the right to change the settings of this negotiation room, while the participants do not necessarily have these rights. Authorization is complex and may change often during the run-time of the system also. We therefore design two inheritable handlers: a) AuthenticatedRequestHandler b) AuthorizedRequestHandler The former class contains the default user authentication logic that ensures that the user has been logged into the system with right user ID and password. The latter class determines if a user has the right to invoke a certain operation by checking whether the user identity has been assigned proper privileges. The relations
6.4. Customization
7. Conclusions and further discussions The WNSS framework designed in this paper provide a flexible and maintainable architecture. The problem presentation, negotiation process control, decision support
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Proceedings of the 38th Hawaii International Conference on System Sciences - 2005
model and overall business transaction support are integrated but can be customized independently at run time. Additional features of WNSS can be added to this framework easily due to the sophisticated design patterns adopted in the implementation. Although the common business negotiation protocol and a practical mediation model have been given, the single side situation analysis support and the multi-party negotiation support with constraint have not been discussed. Cao presented a multi-objective optimization decision model based on problem space description by constraint [16]. Our future work might be on the practical implementation of his model to this framework. Furthermore, the mediation models designed in our WNSS framework rely on the trust in the mediation system. If not all the parties tell the truth to the system, the mediation function will be useless. Therefore, single side situation analysis support model is necessary as a supplement of the mediation model, and this will also be part of our future work.
[10] Stan Matwin, Stan Szpakowicz, and Zbig Koperczak, “Negoplan˖An Expert System Shell for Negotiation Support”, IEEE Expert, Vol. 4, No. 4, 1989, pp. 50-62.
References
[15] Li YJ, Shang W, Feng YQ. “Developing a WNSS based on J2EE architecture”. Proceedings of 2002 International Conference on Management Science & Engineering, Harbin, Mar. 2002
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[11] Stanley Y.W. Su, Chunbo Huang, and Joachim Hammer, “A Replicable Web-based Negotiation Server for E-commerce”, Proceedings of the 33th Hawaii International Conference on System Sciences, Hawaii, 2000. [12] Daniel Druckman, Richard Harris, Bennett Ramberg. “Artificial Computer-assisted International Negotiation˖A Tool for Research and Practice”, Proceedings of the 35th Hawaii International Conference on System Sciences, 2002. [13] Gregory E. Kersten, Sunil J. Noronha. “WWW-based Negotiation Support ˖ Design, Implementation, and Use”, Decision Support Systems, 1999, pp. 135-154. [14] Mareike Schoop, Aida Jertila and Thomas List. “Negoisst: A Negotiation Support System for Electronic Business-to-business Negotiations in E-commerce”, Data & Knowledge Engineering. 2003
[16] Xue Jiaqing. Principles and methods of Optimization, Metallurgy Industry Press, Beijing, 1991, pp. 301-313 (in Chinese). [17] Erich Gamma, Richard Helm, Ralph Johnson, John Vlissides, Elements of Reusable Object-Oriented Software, Addison Wesley Professional, Sep. 1994 [18] Cao Rong-zeng, Li YJ.Multi-objective Optimization Decision Support for Collaborative Negotiation. Forecasting. Vol.22. No.3, 2003 (in Chinese).
[6] Ding Wei, Electronic Business-Oriented Negotiation Support System, PhD dissertation, Harbin Institute of Technology, Harbin, May. 2001, pp. 1-13. [7] Tung Bui and Melvin F. Shakun, “NEGOTIATION SUPPORT SYSTEMS MINITRACK”, Proceedings of the 34th Hawaii International Conference on System Sciences, Hawaii, 2001. [8] Tung Bui. “Building DSS for Negotiators˖A Three-step Design Process”, Proceedings of the 25th Hawaii International Conference on System Sciences, Hawaii, Jan. 1992 [9] Aymanm. Wasfy and Yasser A. Hosni, “TWO-PARTY NEGOTIATION MODELING”. Group Decision and Negotiation, 1998, pp491–518.
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