S. M. Easterbrook, Elicitation of Requirements from Multiple Perspectives. PhD thesis, Imperial College of Science Technology and Medicine, University of London, London, 1991.  Home/Search   Document Details and Download   Summary   Related Articles   Check

....participants who deploy sund7 representation schemes, use a variety of development strategies and hold diverse domain knowledge. We have also proposed an object based framework deploying ViewPoints within which the above problems may be tackled [15] Issues relating to conflict resolution [10] negotiation and dialogue [14] configuration programming [24] and tool support [20, 21, 34] have already been examined within this framework. The term viewpoint has been defined and deployed in a variety of settings in software engineering, particularly in the domain of requirements ....

....implies that either a new agent must be added to the agent hierarchy specification in the AS ViewPoint, or the inconsistent source or destination must be renamed or removed from the specification of the TC ViewPoint. Approaches to conflict resolution in the ViewPoints context have been examined in [10], and a model of conflict resolution proposed. Although it is possible, in principle, to perform any of the generic work plan actions at anytime during specification development, each ViewPoint process 4 Borrower Tabular collection notation definition In ViewPoint Actions ....

S.M. Easterbrook, "Elicitation of Requirements from Multiple Perspectives", Ph.D. Thesis, Department of Computing, Imperial College, London, June 1991.

....in (Richards and Menzies 1998) 3.1 Concept Comparison and Conflict Detection Once the individual KBS have been identified and a merged concept lattice developed, the group meet to compare the viewpoints and identify conflicts. A number of researchers offer different sets of conflict types (e.g. Easterbrook 1991 and Schwanke and Kaiser 1988) We have adopted the four quadrant model of comparison between experts developed by Gaines and Shaw (1989) This model classifies two conceptual models as being in one of four states: Consensus is the situation where experts describe the same concepts using the ....

....and creativity is not something that can be automated. However, since automation is a fundamental goal of this project we extend our approach beyond a general, genial chat by offering as much automated assistance for this step as possible. A number of resolution strategies have been offered (e.g. Easterbrook 1991, Thomas 1976) Easterbrook and Nuseibeh (1996) offer five categories that covers the actions we have found necessary. These are: 1. Resolve, correct any errors; 2. Ignore, no action is performed; 3. Delay, identify the existence of the inconsistency but defer action until a later date; 4. ....

Easterbrook, Steve (1991) Elicitation of Requirements from Multiple Perspectives PhD Thesis, Department of Computing, Imperial College of Science, Technology and Medicine, University of London, London SW7 2BZ.

.... Stage One: Requirements Acquisition and Conversion A knowledge based approach to requirements elicitation has been taken previously (e.g. Easterbrook 1989, Maiden and Rugg 1994, Ruebenstein and Waters 1989) A limitation of most earlier approaches is that they only supported a single viewpoint (Easterbrook 1991). An exception is Nii (1986) who treated the knowledge from each expert as a separate reasoning system. In the approach offered in this paper the goal is to create a shared viewpoint. This stage is currently our least explored with many issues still outstanding. The final design of this stage ....

....engineering research, it is desirable to offer as much automation as possible. Having decided on the nature of the conflict it can be handled in a number of different ways. Thomas (1976) offers five main approaches which are: competition, collaboration, avoidance, accommodation and sharing. Easterbrook (1991) has described these orientations as domination, integration, neglect, appeasement and compromise, respectively. We adopt the strategies offered by Easterbrook and Nuseibeh (1996) resolving (remove inconsistency) ignoring (take no action) circumventing (don t include) delaying (put ....

Easterbrook, Steve (1991) Elicitation of Requirements from Multiple Perspectives PhD Thesis, Department of Computing, Imperial College of Science, Technology and Medicine, University of London, London SW7 2BZ.

....this state thus corresponds to an acceptable requirements specification. 5.5. 2 Elicitation of Requirements from Multiple Perspectives The elicitation of requirements from multiple perspectives is an approach to requirements capture which is being investigated by Easterbrook at Sussex University [Easterbrook 1991]. As with the multi party specification approach, the existence of different viewpoints with legitimate and perhaps conflicting requirements information is acknowledged. In this case, however, it is recognised that each viewpoint will probably have its own way of representing requirements, i.e. ....

EASTERBROOK, S. 1991 Elicitation of Requirements from Multiple Perspectives. PhD thesis (ongoing).

....Representation Martin ERD ERM Relational FDD FD SQL technique scheme T 1 T 2 QUEL Rep n using one or more Figure 1. Perspectives, viewpoints and representations. A perspective is a description of some real world phenomenon with internal consistency and a specified focus [2]. During requirements definition, systems analysts often encounter many different perspectives on the problem being modelled, which may overlap, or even conflict with each other. Part of the process of database design is deciding how to deal with these multiple perspectives. A viewpoint is a ....

S. M. Easterbrook, "Elicitation of requirements from multiple perspectives," PhD thesis, Imperial College of Science Technology and Medicine, University of London, London, 1991.

....3. 1 Phase One: Requirements Acquisition using a knowledge based approach There is nothing new about applying knowledge acquisition techniques to the problem of requirements elicitation [7, 18, 25, 32, 39] A limitation of most earlier approaches is that they only supported a single viewpoint [8]. An exception is Nii [29] who treated the knowledge from each expert as a separate reasoning system. In the approach offered in this paper the goal is to create a shared viewpoint. This phase does not specify any particular type of knowledge representation or the method of acquisition. However, ....

....we want to provide in the future. The process of conflict detection is considered next. 3.4 Stage Four: Concept Comparison and Conflict Detection The concepts generated for each viewpoint in Phase Three are compared in this step. Different types of conflict can be identified. Easterbrook [8] defines three types: interpretation, design, terminology. CONMAN [36] has six different types of inconsistencies full, type, version, derivation, link and reachable consistency. The four quadrant model of comparison between experts developed by Shaw and Gaines [38] has been chosen in this study ....

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Easterbrook, Steve (1991) Elicitation of Requirements from Multiple Perspectives PhD Thesis, Department of Computing, Imperial College of Science, Technology and Medicine, University of London, London SW7 2BZ.

....to review their opinion that inflation wagesRestraint since, in terms of the studied problem, this opinion was irrelevant in 1095 achieving explanations of maximum cover. The multiple worlds reasoning of HT4 has technical advantages over other conflict resolution approaches: ffl Easterbrook [33] lets users enter their requirements into an explicitly labeled viewpoints. He makes the simplifying assumption that all such view 1100 points are internally consistent. HT4 has no need for this, potentially, page 53 of 73 overly restrictive assumption. HT4 can handle inconsistencies within the ....

S. Easterbrook. Elicitation of Requirements from Multiple Perspectives. PhD thesis, Imperial College of Science Technology and Medicine, University of London, 1991. Available from http://research.ivv.nasa.gov/ ¸steve/papers/index.html.

....foriegn sales corporate spending wages restraint domestic inflation sales public confidence 10 10 10 10 10 10 10 10 100 10 10 Fig. 1. Some economics knowledge. P[1] domesticSalesDown, inflationDown P[2] foriegnSalesUp, publicConfidenceUp, inflationDown P[3]: domesticSalesDown, companyProfitsDown, corporateSpendingDown, wagesRestraintUp P[4] domesticSalesDown, inflationDown, wagesRestraintUp P[5] foriegnSalesUp, publicConfidenceUp, inflationDown, wagesRestraintUp P[6] foriegnSalesUp, companyProfitsUp, corporateSpendingUp, investorConfidenceUp ....

....sales company profits foriegn sales corporate spending wages restraint domestic inflation sales public confidence corporate spending wages restraint inflation public confidence 10 10 10 10 10 10 10 Fig. 4. World #2 is generated from Figure 1 by combining P[1] P[2] P[3], and P[4] World #2 assumes companyProfitsDown and covers 67 of the known OUT puts. In the case of the observed OUT puts being finvestorConfidenceUp, wagesRestraintUp, inflationDowng,and the observed INputs being fforiegnSalesUp, domesticSalesDowng, 115 HT4 can connect OUT puts back to INputs ....

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S. Easterbrook. Elicitation of Requirements from Multiple Perspectives. PhD thesis, Imperial College of Science Technology and Medicine, University of London, 1991. Available from http://research.ivv.nasa.gov/ ¸steve/papers/index.html. Menzies; page 17 of 18

....collaborative requirements negotiation process. Groupware should support activities identified as major problems in RE, including domain knowledge acquisition and traceability [16] The issue here is that the participants in the process have multiple perspectives over the system to be designed [5], and that communication in RE is much more about developing an understanding of each other s views and perspectives, about sharing knowledge and about learning as a result of a shared experience [14] Consequently, we focus on the ability of team members to express, discuss and negotiate ....

....as we believe that real time collaboration and discussions are a necessary component of the group RE session. Specification of requirements is regarded as a knowledge acquisition task, and conversation is the main vehicle for gathering, clarifying and validating the knowledge about requirements [5]. Thus synchronous communication as well as access to a shared workspace is important in RE, as detailed below. Telepresence is defined as a way of giving distributed participants a feeling that they are in the same meeting room [10] In RE, as in any negotiation meeting, a sense of presence is ....

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S.M. Easterbrook, "Elicitation of requirements from multiple perspectives", PhD Thesis, Imperial College of Science Technology and Medicine, University of London, 1991.

....in terms of the studied problem, this proved to explain less of the required behaviour that Dr. Thick s option that foriegnSales companyProfits. The multiple worlds reasoning of HT4 has technical advantages over other con 1210 flict resolution approaches: page 41 of 56 ffl Easterbrook [33] lets users enter their requirements into an explicitly labeled viewpoints. He makes the simplifying assumption that all such viewpoints are internally consistent. HT4 has no need for this, potentially, overlyrestrictive assumption. HT4 can handle inconsistencies within the opinions 1215 of a ....

S. Easterbrook. Elicitation of Requirements from Multiple Perspectives. PhD thesis, 1635 Imperial College of Science Technologyand Medicine, University of London, 1991. Available from http://research.ivv.nasa.gov/ ¸steve/papers/index.html.

....engineering approaches, our approach can usefully augment existing knowledge engineering approaches. Fourthly, the abductive approach described here can be extended from maintenance to conflict resolution in requirements analysis. Requirements modelling (RM) researchers such as Easterbrook [13], Finkelstein et al. 18] and Nuseibeh [42] argue that we should routinely expect specifications to reflect different and inconsistent viewpoints. The software specification problem then becomes one of managing these different viewpoints. In current methodologies, handling and resolving ....

....found that it easier to build efficient implementations [33, 34] using the above graph theoretic approach than using purely logical approaches (e.g. 23] Easterbrook s Synoptic tool only permits comparisons of two viewpoints [13, p113] Abduction can compare N viewpoints. Also, Easterbrook [13] lets users enter their requirements into an explicitly labeled viewpoints which he assumes are internally consistent. We have no need for this restrictive (and possibly overly optimistic) assumption. Abduction can handle inconsistencies within the opinions of a single user. Further, our ....

S. Easterbrook. Elicitation of Requirements from Multiple Perspectives. PhD thesis, Imperial College of Science Technology and Medicine, University of London, 1991. Available from http://research.ivv.nasa.gov/ ¸steve/papers/index.html.

.... inflationDown P[2] foriegnSalesUp, publicConfidenceUp, inflationDown P[3] domesticSalesDown, companyProfitsDown, corporateSpendingDown, wagesRestraintUp P[4] domesticSalesDown, inflationDown, wagesRestraintUp P[5] foriegnSalesUp, publicConfidenceUp, inflationDown, wagesRestraintUp P[6]: foriegnSalesUp, companyProfitsUp, corporateSpendingUp, investorConfidenceUp Figure 4: Proofs from Figure 3 connecting OUT = finvestorConfidenceUp, wagesRestraintUp, inflationDowng back to INputs= fforiegnSalesUp, domesticSalesDowng. ffl x Gamma Gamma y denotes that y being up or down ....

....is only 10. Menzies: RE Qualitative Causal Diagrams; page 6 of 15 company profits investor confidence foriegn sales corporate spending wages restraint inflation public confidence 10 10 10 100 10 10 Figure 5: World #1 is generated from Figure 3 by combining P[2] P[5] and P[6]. World #1 assumes companyProfitsUp and covers 100 of the known OUT puts. company profits foriegn sales company profits foriegn sales corporate spending wages restraint domestic inflation sales public confidence corporate spending wages restraint inflation public ....

[Article contains additional citation context not shown here]

S. Easterbrook. Elicitation of Requirements from Multiple Perspectives. PhD thesis, Imperial College of Science Technology and Medicine, University of London, 1991. Available 320 from http://research.ivv.nasa.gov/ ¸steve/papers/index.html.

....participants who deploy sundry representation schemes, use a variety of development strategies and hold diverse domain knowledge. We have also proposed an object based framework deploying ViewPoints within which the above problems may be tackled [15] Issues relating to conflict resolution [10] negotiation and dialogue [14] configuration programming [24] and tool support [20, 21, 34] have already been examined within this framework. The term viewpoint has been defined and deployed in a variety of settings in software engineering, particularly in the domain of requirements ....

....implies that either a new agent must be added to the agent hierarchy specification in the AS ViewPoint, or the inconsistent source or destination must be renamed or removed from the specification of the TC ViewPoint. Approaches to conflict resolution in the ViewPoints context have been examined in [10], and a model of conflict resolution proposed. Although it is possible, in principle, to perform any of the generic work plan actions at anytime during specification development, each ViewPoint process WORK PLAN Assembly Actions In ViewPoint Actions Inter ViewPoint Actions ViewPoint Trigger ....

S.M. Easterbrook, "Elicitation of Requirements from Multiple Perspectives", Ph.D. Thesis, Department of Computing, Imperial College, London, June 1991.

....AS ViewPoint, or the inconsistent source or destination must be renamed or removed from the specification of the TC ViewPoint. Approaches to conflict resolution (as distinguished from inconsistency handling) in the ViewPoints context have been examined, and models of conflict resolution proposed [15, 17]. A treatment of these WORK PLAN Assembly Actions In ViewPoint Check Actions Inter ViewPoint Check Actions ViewPoint Trigger Actions Process Model SPECIFICATION WORK RECORD add(Library) add(Borrower) add(publication) connect(Library, publication, Connected to) connect(publication, ....

....the two connected ViewPoints. Broken arrows denote relationships that do not yet hold. 6. Experiences To validate and demonstrate our approach, a number of case studies and computer based tools were developed an outline description of which follows. Related issues including conflict resolution [17], negotiation and dialogue [20] and configuration programming [32] were also examined in this setting. 6.1. Tool Support A generic, computer based prototype environment called The Viewer [45] has been built in Objectworks Smalltalk, to support the ViewPoints framework. The Viewer (Fig. 14) runs ....

S. M. Easterbrook (1991); "Elicitation of Requirements from Multiple Perspectives"; Ph.D. Thesis, June 1991; Department of Computing, Imperial College, London, UK.

....problem. This finding is reflected in the literature, where the fundamental problem has been attributed to: lack of commitment by all parties [Wright 1991] coarse granularity of traceable entities [Ramamoorthy et al. 1986] immature integration technology [Brown et al. 1992] knowledge management [Easterbrook 1991]; information complexity [Hoffman 1990] hidden information [Robinson 1991] and project longevity [Mays et al. 1985] Similarly, the problems that practitioners believed improved requirements traceability should address were just as diverse. This finding is also reflected in the literature: to ....

.... in mind and to assist user acceptance testing [Ramamoorthy et al. 1984] to enable safety analysis, audits, and change control [Hamilton Beeby 1991] to provide the ability to understand systems from multiple points of view and to assist the pulling together of fragmented information [Easterbrook 1991]; and to permit flexible process modelling [Fischer 1991] These findings demonstrate that: a) the phrase requirements traceability problem is used to umbrella many underlying problems; and that (b) improvements are expected to yield the solution to additional (and often incompatible) problems. ....

Easterbrook, S. (1991). Elicitation of Requirements from Multiple Perspectives, Ph.D Thesis, Department of Computing, Imperial College of Science, Technology & Medicine, London University, June.

....viewpoint, so that it is available for later re examination if necessary. 4. SUMMARY This paper has described a model for integrating conflicting domain descriptions. This forms part of a larger model of requirements engineering based on the representation of multiple viewpoints, as described in Easterbrook [1991]. The model recognises that carefully managed conflict can improve the quality of the requirements specification, and encourages the expression of conflict by allowing participants to describe their viewpoints separately. Expression of conflict needs to be balanced with productive resolution ....

Easterbrook, S. M. (1991) Elicitation of Requirements from Multiple Perspectives, PhD Thesis, Imperial College, University of London.

....found that it is easier to build efficient implementations [17, 18] using the above graph based approach than using purely logical approaches. These tools do not suffer from the restrictions of other tools. For example, while Easterbrook s SYNOPTIC tool only permits comparisons of two viewpoints [6], our approach can compare N viewpoints. Lastly, the approach is simple enough that we can perform experiments on the utility of multiple world reasoning under different circumstances. The remainder of this paper describes such an experiment. 3. Looking for Multiple Viewpoints In exploring the ....

S. Easterbrook. Elicitation of Requirements from Multiple Perspectives. PhD thesis, Imperial College of Science Technology and Medicine, University of London, 1991.

....just one point of view, and does not ignore concerns which interfere with the dominant concern. In software design, effective collaboration is essential. It is vital that there be no losers from any conflict in the specification process, as the commitment of all participants must be maintained [Easterbrook 1991]. Hence, encouragement of conflict must be matched with resolution methods which strive to satisfy all parties. An integrative approach should be adopted, to ensure that when divergent views arise they are incorporated into the process. The ultimate goal of the requirements process should be to ....

....other type of decision procedure. 4. SUMMARY This paper has described a model of conflict resolution which can be used to integrate conflicting domain descriptions. This forms part of a larger model of requirements engineering based on the representation of multiple viewpoints, as described in Easterbrook [1991]. In recognition of the fact that carefully managed conflict can help eliminate errors and improve the quality of the requirements specification, the model encourages the expression of conflict by allowing participants to describe their viewpoints separately. Expression of conflict needs to be ....

Easterbrook, S. M. (1991) Elicitation of Requirements from Multiple Perspectives, PhD Thesis, Imperial College, University of London.

....approach, it is the shared domain model. The formalised viewpoints model makes no assumptions about common ground, and even allows different representation schemes to be used. However, it is not yet clear how correspondences can be found between viewpoints. 3 Representing Multiple Viewpoints In [2], we describe a model of requirements elicitation from multiple viewpoints, where a viewpoint is a selfconsistent description of an area of knowledge with an (a) maximise(circulation) maximise(circulation) lending li lending limits fines (b) maximise(circulation) maximise(circulation) ....

Easterbrook, S. M. (1991a) Elicitation of Requirements from Multiple Perspectives. PhD Thesis, University of London.

....area is described below. 7 Computer Supported Negotiation 7.1 Outline The Computer Supported Negotiation (CSN) model takes the ViewPoints framework as a basis, and defines a process for resolving conflicts between ViewPoints. The project was carried out as a PhD thesis, and is described fully in Easterbrook (1991). A shorter account of the conflict resolution model can be found in Easterbrook (1993) CSN assumes during the elicitation process, it is convenient to represent separately contributions from different sources, ignoring conflicts between them. This offers two advantages: individual contributions ....

Easterbrook, S. M. (1991) Elicitation of Requirements from Multiple Perspectives; PhD Thesis; University of London.

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S. M. Easterbrook, Elicitation of Requirements from Multiple Perspectives. PhD thesis, Imperial College of Science Technology and Medicine, University of London, London, 1991.

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Steve M. Easterbrook. Elicitation of Requirements from Multiple Perspectives. PhD thesis, Imperial College of Science Technology and Medicine, University of London, London, 1991. 14

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