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Dcc2010 cascini del_frate_fantoni_montagna

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Among the various model based theories, the Gero's FBS framework is acknowledged as a well-grounded, effective and tested reference for describing both analysis and synthesis design tasks. Despite its design-centric nature, the FBS model can provide a valid support also to represent processes and tasks beyond its original scope. The specific interest of the authors is to extend the FBS application to model also uses and misuses of objects, interpretations of the users, needs and requirements. In fact, as partially addressed also in literature, some issues arise when the classical FBS framework is adopted to model particular aspects such as the user's role, values and needs, as well as to produce an explicit representation of failures and redundant functions. The full paper presents an extended classification of aspects, beyond the design perspective, which currently cannot be represented by the FBS model and some directions for its possible extension. Several examples clarify the scopes and the characteristics of the proposed model. The current state of development of the author’s work still cannot be considered an integrated model, but relevant possibilities to extend the domain of applicability of the FBS framework emerge.

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Dcc2010 cascini del_frate_fantoni_montagna

  1. 1. FOURTH INTERNATIONAL CONFERENCE ON DESIGN COMPUTING AND COGNITION 12–14 July 2010 University of Stuttgart, Stuttgart, Germany Beyond the design perspective of Gero's FBS framework Gaetano Cascini (Politecnico di Milano) Luca Del Frate (TU Delft) Gualtiero Fantoni g.fantoni@ing.unipi.it (Università di Pisa) Francesca Montagna (Politecnico di Torino) Gualtiero Fantoni – g.fantoni@ing.unipi.it UNIVERSITÀ DI PISA
  2. 2. 2/16 Summary Motivation and approach to research Discussion on the situated FBS framework FBS model and main processes Observations from literature Proposal for an extension to user modeling Exemplary application Conclusions and further developments Gualtiero Fantoni – g.fantoni@ing.unipi.it UNIVERSITÀ DI PISA
  3. 3. 3/16 Motivation and approach to research (1) Affordances and the role of the users are of particular interest FBS is a designer centric model Open issues Can the FBS framework be used to represent the user perspective? Do we need some new variables for the model (goals, manipulation, plans, etc..from Brown&Blessing2005)? By doing that, is it possible to model also affordances, misuses, alternative uses, failures, etc..? Are there some consequences? Is the model still stable? Gualtiero Fantoni – g.fantoni@ing.unipi.it UNIVERSITÀ DI PISA
  4. 4. Entities to be managed within the extended framework 1. Actors and relations in the External World. (e.g. user needs, “the working environment”, “rest of the world”, the interpretations of artifacts). 2. Product usability and use context. The concept of “guess” has been used for describing the implicit assumption of context for making use of a device. 3. Product affordance. “Affordances are possible actions” and in particular “the affordances A of a device are the set of all potential human behaviors (Operations, Plans, or Intentions) that the device might allow”. 4. Failures and their perception. 5. Alternative Uses. “Product alternative uses are all the possible uses connected to the context and to the material decomposition of the device.” 6. Misuses are defined as those conditions in which the user manipulates the product in ways that were not intended by the designer, still keeping the same goal. Gualtiero Fantoni – g.fantoni@ing.unipi.it UNIVERSITÀ DI PISA
  5. 5. Analysis of Gero et al. works from 1986 to 2009 Gero’s numbers: more than 49 books and over 600 papers and book chapters from 1986 to 2009 259 papers (675,408 words) downloaded from http://mason.gmu.edu/~jgero/ After tokenization and lemmatisation ~22,000 lemmas 20000 18000 16000 14000 12000 10000 8000 6000 4000 2000 0 design agent structure designer knowledge behaviour function From year 2000 action memory situatedness problem environment interaction From year 2002 F-B-S interpretation ontology user failure affordance interface Gualtiero Fantoni – g.fantoni@ing.unipi.it UNIVERSITÀ DI PISA
  6. 6. … a problem with the year 2010 Gero’s numbers: more than 600 papers from 1986 to 2009 (2010) 270 papers downloaded from After tokenization and lemmatisation ~22,000 lemmas Kannengiesser, U and Gero, JS, 2010?, A PROCESS FRAMEWORK OF AFFORDANCES IN DESIGN 600 500 400 300 200 100 0 52 times 136 times user failure affordance interface .. in this paper the word designer appares only 6 times Gualtiero Fantoni – g.fantoni@ing.unipi.it UNIVERSITÀ DI PISA
  7. 7. 7/16 Discussion on the situated FBS framework (1) Three classes of variables: Function (F) variables: teleology of the object, i.e. what it is for Behavior (B) variables: what the object does Structure (S) variables: components and their relationships, i.e. what it is Eight elementary steps in design: 1. Formulation 2. Synthesis 3. Analysis 4. Evaluation 5. Documentation 6-8. Reformulation steps Gero and Rosenman, 1990 Gualtiero Fantoni – g.fantoni@ing.unipi.it UNIVERSITÀ DI PISA
  8. 8. 8/16 Discussion on the situated FBS framework (2) Three interacting environments (the interaction between designer and environment impacts the course of designing): External world: things and their representations outside the design agent Interpreted world: internal, interpreted representation of that part of the external world that the designer interacts with Expected world: environment in which the effects of actions are predicted according to current goals and interpretations of the current state of the world Three classes of processes: Interpretation: Xe Xi (push-pull) Focusing: Xi Û Xei Action: Xei ® Xe (transformation) Gero and Kannengiesser, 2004 Gualtiero Fantoni – g.fantoni@ing.unipi.it UNIVERSITÀ DI PISA
  9. 9. Designer centric vs User centric FBS representation Can we introduce, as is, the user in the FBS framework? Since “a user designs how to use an artifact for herself/himself [..] it is not surprising that the FBS framework can be used to describe a user's behavior”. REVIEW 2 Nevertheless, the goal of the authors is to propose a comprehensive representation of the cognitive aspects related to the product use context, in order to strengthen the design process, thus still with a close link with the designer’s perspective. The idea is that the FBS framework can be used to describe other processes related with design (e.g. use, failures) and other entities (e.g. affordances). Gualtiero Fantoni – g.fantoni@ing.unipi.it UNIVERSITÀ DI PISA
  10. 10. Designer centric vs User centric FBS representation From the designer’s point of view the designed device is a: user acting on a structure in a certain environment in a certain way From the user’s point of view the device is an: interface on which he/she can act (properly and improperly) and from which he/she can receive a feedback Gualtiero Fantoni – g.fantoni@ing.unipi.it UNIVERSITÀ DI PISA
  11. 11. Affordances 1 from literature Norman [1988] believes “that affordances result from the mental interpretations of things, based on our past knowledge and experience applied to our perception of the things about us.” Maier and Fadel [2003] (M&F) consider affordances to be “potential uses” of a device. Q1 Can I say that affordances are mental representations of possible uses (or better, uses the user believes as possible)? Gualtiero Fantoni – g.fantoni@ing.unipi.it UNIVERSITÀ DI PISA
  12. 12. Affordance 2 from literature Brown & Blessing 2005: affordance ~ function but affordances do not include the notion of teleology (what the artefact is for) “Thus, unlike functions, affordances may or may not be associated with a goal. Also, if a goal is specified, affordances may or may not support it [..] In fact, as M&F point out, some affordances may be undesirable, clashing with the goal: what they call “negative affordances”” Q2 But if now Affordances may or may not be associated with a goal, were they in the past associated with a goal? Gero 2010: “Affordances also appear similar to behaviour. [..] Affordances are an agent’s potential actions that interact with an artefact structure and thereby produce artefact behaviours of relevance (with positive or negative consequences).” Q3 Artefact behaviours of relevance is something that can be interpreted in the space of GOALS? Gualtiero Fantoni – g.fantoni@ing.unipi.it UNIVERSITÀ DI PISA
  13. 13. Consequences If Q1, Q2, Q3 are true: Affordances are mental representations of expected (by the user) possible uses of an artefact. Therefore each possible use can be connected with possible consequences that can be exploited or avoided (~ goals). Therefore affordances can be “functions with a weak link with goals”. Maier & Fadel 2009: structure Þ affordance Þ behaviour Brown & Blessing 2005: affordance ~ function Therefore we can affirm: structure Þ ~ function Þ behaviour But in Gero 2003: structurei Þ behaviouri Þ functioni So, do we miss some arrows in the FBS model (e.g. from structure to function)? Can we add AFFORDANCES in the FBS framework? And if yes, where? Gualtiero Fantoni – g.fantoni@ing.unipi.it UNIVERSITÀ DI PISA
  14. 14. A starting proposal Our proposal is that: The user manipulates a structure. The structure produces a set of behaviours. The user interprets (via his/her knowledge) some of them as functions.  B=M(S); F=K(B). Repeated experiences bring the user to simplify the process: S Þ B and B can be used for potential F = A. The user sees a structure. The user imagines (knowledge) to manipulate the structure, imagines it produces some behaviours that he can use for achieving a goal (potential function = affordance).  The entire process is in the user’s mind (expected world)  In time the process can become: S Þ B Þ potential F = A  But, the direct link S«A is useful “to spend less cognitive effort and make fewer errors” and it also increases the speed in decision making. Gualtiero Fantoni – g.fantoni@ing.unipi.it UNIVERSITÀ DI PISA
  15. 15. Affordance and learning From the designer’s perspective From the user’s perspective Bei Aed i Bi Ad i Gualtiero Fantoni – g.fantoni@ing.unipi.it UNIVERSITÀ DI PISA Ae Be UIe UId i UIed Aeu i Au i Ae Se Inti Intei Bei Bi Be UI: the part of a product which has been intentionally devised by the designer for hosting the user-product interactions.
  16. 16. Consequences Affordances can be introduced in the FBS A connection between Si and Ai can be added There is a difference in the interpeted affordances. Both the desinger and user perceive both true and false affordances, but Ad and Au can be different. E.g. Sliding or turnable door? HP: Au:turnable. M(S)Bsu i≠Beu i. Fui is interpreted and Au is updated. (See after) UI differs from Int (the actual used interface) UI can contain Int (the case of REC key in the remote of VHS) UI can be contained in Int (the case of the fan in case of CUP overclocking) Gualtiero Fantoni – g.fantoni@ing.unipi.it UNIVERSITÀ DI PISA
  17. 17. Use From the designer’s perspective From the user’s perspective Me Mi i Inti Mei Bei Aei Fei Bi Au Fi Ae Be Se Fe Intei For the designer user’s Manipulation is a behavior. He/she consider the artifact as an “user using his machine” Gualtiero Fantoni – g.fantoni@ing.unipi.it UNIVERSITÀ DI PISA
  18. 18. Comparing designer and user perspective .. The alternative uses are the possible behaviors B (interpreted by the user as possibilities of achieving goals G) of the system coming from its structure, but totally disconnected from the goals the designer interpreted as user needs and the product was designed for. alternative uses can be described as G≠ G, Bs≠ Bs. M(S)Bsi=Bei u du du u The misuses. 1- The user believes the product affords A, but A was not intended by the designer. 2- User and designer agree on the product affordances. Misuses are the possible behaviors (interpreted by the user as possibilities of achieving goals) of the system, coming from the manipulation of its structure and linked to the goals the product was designed for. misuses can be described as: Gu = Gd, Bsu ≠ Bsd. There is at least a problem in Meu and the manipulation forseen by the designer. Gualtiero Fantoni – g.fantoni@ing.unipi.it UNIVERSITÀ DI PISA
  19. 19. Conclusion and open questions? The introduction of the user seems able to explain in some way also affordances, misuses, alternative uses, etc. Some of them (affordances?) can (?) be introduced also in the desinger perspective. Some of them can be explained by comparing the user point of view and the designer point of view. 1. Do we miss something? 2. Are the variable, we want to introduce, really independent? 3. Is it necessary to introduce manipulation or can it be integrated in B? 4. If we introduce the goal, what is the consequence? Gualtiero Fantoni – g.fantoni@ing.unipi.it UNIVERSITÀ DI PISA
  20. 20. The unforeseen consequence Function (F) of an artefact is defined as its teleology. It is ascribed to behaviour by estabilishing a teleological connection between a human’s goal and measurable effects of the artefact. (Kannengiesser 2010) If we introduce goals in the framework, we do not need Functions anymore, because they can be expressed as a behaviour interpreted through (linked to) the goals. And .. what if “Functions do not exist”. Is it bad or it is good? Gualtiero Fantoni – g.fantoni@ing.unipi.it UNIVERSITÀ DI PISA

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