デザインの形式表現への BDI フレームワークの適用
デザインにおける思考過程の計算モデルに向けて

Application of the Belief-Desire-Intention Framework to Formal
Representation of Designing
Towards a computational model of thought process in designing○藤井 晴行*1，ユヴァル・カロン*2，篠崎 健一*3
Haruyuki FUJII＊1, Yuval KAHLON＊2 and Ken-ichi SHINOZAKI＊3*1 東京工業大学・建築学系教授

博士(工学)

Professor, Department of Architecture and Building Engineering, Tokyo Institute of Technology, Ph.D.
*2 東京工業大学・建築学系

助教

博士(工学)

Assistant Professor, Department of Architecture and Building Engineering, Tokyo Institute of Technology, Ph.D.
*2 日本大学・建築工学科

准教授

工修

Assistant Professor, Department of Architecture and Architectural Engineering, Nihon University, Ph.D.
キーワード：デザインの理論的根拠; 思考過程; 志向性; 計画; 図式.

Keywords: Design Rationale; Thought Process; Intentionality; Plan; Schema.

1. Introduction

designing. It is assumed that actions in designing are situated

The objectives of this study are to enrich Belief-in the sense that a course of actions is determined by an

Desire-Intention, or BDI in short, framework [5] so as to beinteraction between external factors, i.e., the environment

employed in design research and computing and to create awhere it is performed, and internal factors of the designer, i.e.,

method of extracting the rationale of actions in designingsome goals, beliefs, etc. The framework is called as thefrom narratives about designing. The rationale is composed ofsituated FBS framework. However, to our knowledge, formal

propositional attitudes, which are categorized as belief, desire,

representation of cognitive processes in designing, which isor intention. Since designing is a purposive activity, apromising for making a computational model of architecturaldesigner has desire to provide a particular functionality anddesign process, is not sufficiently proposed [3][4]. Akin [3]intention to make something to fulfill the desire. Formal

proposed a model of information processing in designing on

representation of a processes of designing and its product or a

the basis of the protocols in designing. Gero and Fujii [4]part of them is helpful to computer aided design research andproposed a cognitive framework of a situated design agent.

design computing, as well as to design science. This does not

The original contribution is to construct the theoretical andmean that we intend to let a computer replace a human

computational foundations of normative study on designing

designer. We can leave what can be done by computation withand building. In this context, our naïve research question is:

a computer and leave what a computer cannot do and what is

how does the BDI framework help us to explain the

fun to do for human with a human designer.

transitions of residential houses from past to present, and to

Various means to describe states of affairs concerning

generate trajectories towards their preferable future?

architecture and architectural spaces exist and are being

Reformulation (Type 1)

improved. Formal models of designing were proposed as well
[1][2]. Gero [1] proposes to represent an artifact from threeF

Reformulation(Type 3)S

different kinds of aspects, i.e., function, behavior, andstructure. He models a process of designing as a sequential
cycle of transformations among the representations from theReformulation(Type 2)

Formulation

aspect of function, behavior, or structure. This framework fordescribing designing is called Function – Behavior - Structure
framework, or FBS framework. Gero and Kannengiesser [2]sophisticate the FBS framework to deal with situatedness in
日本建築学会情報システム技術委員会
第 44 回情報･システム･利用･技術シンポジウム論文集， 503-506 ， 2021 年 12 月，京都
Proceedings of the 44th Symposium on Computer Technology of Information ，Systems and Applications ， AIJ ， 503-506 ， Dec. ， 2021 ， Kyoto

Documentation

D

Analysis

Synthesis
Be

Evaluation

Bs

Figure 1. Model of Design Process with FBS Framework.

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2. The BDI Framework(3) The propositional attitudes and their relationships are

The primary reason of an action is explained in terms offormally represented in predicate logic.

propositional attitudes. The notion of a propositional attitude(4) The reason of a course of actions to improve the quality of[7] refers to a mental structure composed of a content of anlife by introducing modern technologies are explained byagent’s cognition or opinion and a mental state held by theusing practical reasoning as well as syllogism.

agent toward the content [8]. The content is expressed as a(5) Thought experiments are executed to generate different

proposition whose truth value can be assigned. Specifically,

trajectories of retrofitting traditional houses based on

the primary reason of an action is explained by combining

different sets of propositional attitudes.

desire and belief, which are propositional attitudes. An action
is regarded as the emergence of a bodily movement toward acertain matter X, of agent A’s desire – agent A wants, or hopes,
the matter X -, entailing agent A’s belief – agent A believes, or
expects, that the matter X may exist now or in the future [9].
Belief: The notion of belief refers to what an agent believes,i.e., the current matters perceived or interpreted, the pastmatters remembered, the future matters expected or predicted,
the relationships among these matters, the significance orvalue of matters believed, the likelihood of a course of action
achieving certain effects [6], and so on.
Desire: The notion of desire refers to an agent’s pro attitude
towards a matter or preferences over matters such as states of

Figure 2. Retrofit of a Traditional House in Izena Island

affairs, courses of events, or courses of action. An agent isallowed to have inconsistent desires and does not have toPractical Reasoning

believe that its desire is achievable [6].

Figure 3 shows a simple pattern of practical reasoning where

Intention: The notion of intention refers to an agent’s

an intention is derived from a desire and some beliefs.

commitment to a certain goal and courses of action in the

Suppose that an agent has a desire (D:) to fulfill a state of

future towards the goal [5][6]. The goal committed is selectedaffairs which is referred to by proposition D0 (D:D0). With

from the goals, which is a consistent subset of desires that thethe belief (B:) that the result of action A1 is a state of affairs

agent might pursue [6]. The courses of action committed arereferred to by proposition D0 (B:A1=>D0), the agent infers

selected after deliberation based on the desire and belief.

that action A1 becomes a candidate of an action to be
performed (B:alt.A1). If the agent has the belief that action

3. Relations among Propositional Attitudes in Architecture

A1 can be done, or is available (avl.), in a certain

The typical patterns of the relationships among belief, desire,circumstance (B:avl.A1), then the agent intends (I:) to do

and intention in the rationale of building a house are shown.

action A1 (I:do.A1). This pattern can be simplified as shown

The patterns are extracted from the contents of conversationsin Figure 4 where the availability of action A1 is implied or

about building and rebuilding of traditional houses. It isunverified yet. This pattern is equivalent to the application ofassumed that an agent is rational in the sense that only athe inference rule of the practical reasoning proposed byconsistent set of desires is selected.

Aristotle. Here, A=>B expresses that if action A is performed

The procedure of whole study is shown below. This paper

than B becomes true.

shows the result of the second step.
(1)

Sentences
propositionalinnarratives

attitudes

andbehindessaysactions,

conveyingtargetedatintroducing modern technologies into traditional houses,
are analyzed and categorized into three categories - belief,

Figure 3. Practical Reasoning 1.

desire, and intention.
(2) The propositional attitudes are associated with each otherin terms of causal relations and logical dependencies toconstruct the entire structure.

報告 H88Figure 4. Practical Reasoning 2.

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Figure 5 shows a simple pattern of a combination of ato do action A2 (I:do.A2).

syllogism and practical reasoning to derive an intention froma desire and a belief. Suppose again that an agent has a desire
to fulfill a state of affairs which is referred to by proposition
D0 (D:D0). With the belief that if D1 is satisfied then D0 issatisfied (B:D1->D0), the agent articulates the primary desire
as a desire to realize a state of affairs expressed by proposition
D1 (D:D1). With the belief that the result of action A1 is a

Figure 7. A Process of Selecting an Action by Comparison.

state of affairs referred to by proposition D1 (B:A1=>D1), theagent intends to do action A1 (I:do.A1).

Articulation
Vague Information is articulated on the basis of an agent’s
belief about the relation between class and subclass, class andinstances, and so on. Figure 8 depicts a process where a vague
intention, which cannot be executed by itself, is articulated so

Figure 5. Syllogism and Practical Reasoning.

as to make the vague intention executable. For example, eventhough we intend to roof a house, we cannot complete theSelection of Action Alternatives

plan without deciding the material used for roofing and the

Figure 6 shows a pattern in which an action is selected fromconstruction method, i.e., thatched, tile, galvanized iron, etc.

two alternatives. Suppose that an agent has a desire to fulfill a

After an agent has intention to do vague action A1 (I:do.A1),

state of affairs which is referred to by proposition D0 (D:D0).

A1 is articulated. Suppose that the agent believes that action

If the agent believes that two different actions A1 and A2 haveA1’ and action A1” instances of the vague action A0

the same result D0 (B:A1=>D0, B:A2=>D0) then the agent(B:A1’->A1, B:A1”->A1). Then, the agent believes that

believes that action A1 and A2 are alternatives to satisfies

action A1’ and action A1” are alternatives (B:alt.A1’,

desire D0 (B:alt.A1 and B:alt.A2). In the case that the agent

B:alt.A1”).

believes that action is not possible (imp.) to be executed

Vague beliefs and vague desires would be articulated in the(B:imp.A1), the agent necessarily selects action A2 andsimilar way. Articulation of a vague desire is mentioned in theintends to do action A2 (I:do.A2).

next session.

Figure 6. A Process of an Action Candidate Selection.
Figure 7 shows a pattern in which an action is selected

Figure 8. A Process of Articulation.
Resolution of Conflictfrom two alternatives by comparing them and the first

Figure 9 depict a process of resolving a conflict among

selection is given up because of a certain situation. Suppose

alternatives. In a situation where two actions conflict withthat an agent has a desire to fulfill a state of affairs which iseach other, one of them is selected and the other one is givereferred to by proposition D0 (D:D0). The agent believes thatup. An agent believes that its desire (D:D1) and desire (D:D2)

action A1 and A2 are alternatives to satisfies desire D0

articulate desire (D:D0). Abductive reasoning is employed to(B:alt.A1 and B:alt.A2). The agent compares the alternatives

derive a desire to fulfill a state of affairs which is referred towith each other and concludes that action A1 is better than A2

by proposition D1 (D:D1) from a desire to fulfill a state offor some reason. Therefore, the agent intends to do action A1

affairs which is referred to by proposition D0 (D:D0) and a(I:do.A1), not action A2. Suppose that the agent become

belief about the relation that if D1 is satisfied them D0 isaware that action A1 cannot be executed after the decisionsatisfied (B:D1->D0). Equivalently, Desire D2 (D:D2) ismaking (B:imp.A1). Then, the agent gives up action A1 andderived from desire D0 and belief D1->D0 (B:D1->D0). With

necessarily selects action A2 instead of action A1 and intends

the belief that the result of action A1 is a state of affairs

報告 H88－ 505 －

referred to by proposition D1 (B:A1=>D1), the agent believes

executing the action.

that action A1 becomes an alternative (B:alt.A1). Equivalently,
with the belief that the result of action A2 is a state of affairs
referred to by proposition D2 (B:A2=>D2), the agent believes
that action A2 becomes an alternative (B:alt.A2). Supposethat the agent believes that the result of action A1 is a state ofaffairs referred to by proposition ¬D2 (B:A1=>¬D2) and thatthat of action A2 is a state of affairs referred to by proposition¬D1 (B:A2=>¬D1). As a consequence, action A1 and action
A2 are not compatible with each other. The agent gives up

Figure 10. A Process including Execution of an Action.

desire D1 and intends to do action A2 (I:do.A2).
Conclusion
The main conclusions at this moment are that it is possible toextract the rationale of actions in architectural activity fromnarratives, and that this rationale could be represented in aform available for design computing. The next steps are toassign each type of relation among propositional attitudes
Figure 9. A Process of Articulation.

with appropriate inference rules, and to formally represent
these in order to confirm that they can be dealt with

Substantial Aspect and Conceptual Aspectcomputationally.

A set of propositional attitudes is a subset of all
constituents constructing a self-conscious experience

Acknowledgmentin the conceptual aspect. A self-conscious experience

Narratives used for the BDI analysis here are collected inalso has the substantial aspect. Some constituents inIzena Island in Okinawa prefecture. We would like to thankthe conceptual aspect emerges through the interaction

residents of the island for the opportunity of conversation. We

between an agent’s body and its environment in thewould like to thank some students of Shinozaki Lab. at Nihon

substantial aspect.

University and some students of Fujii Lab. at Tokyo Institute

When an action is executed as intended, theof Technology for data collection and analysis.

relations among the agent and its environment arechanged. Figure 10 depicts this process. The changes
are experienced in the substantial aspect (the lower
part of the figure) and the conceptual aspect (theupper part). Suppose that an agent faces a situation
where the agent believes the thing referred byproposition D0 is not satisfied (B:¬D0). Suppose alsothat the current situation is not preferable for theagent and that the agent has a desire to make a state ofaffairs which renders proposition D0 true (D:D0). Throughthe process discussed above, the agent intends to do action A1(I:do.A1) so as to satisfy its desire. Suppose that the agent
executes the action and changes the relationships with its
environment (action). The agent experiences the state after
the action and confirms the situation where the agent believes
that proposition D0 is rendered true (B:D0). The agent also
believes that the situation renders proposition E0 true (B:E0)［References］

1) Gero, J., Design Prototypes: A Knowledge Representation
Schema for Design, AI Magazine, 11(4), 1990.
2) Gero, J. and Kannengiesser U., The Situated FunctionBehavior-Structure Framework, Design Studies, 25,
2004.
3) Akin, O., Psychology of Architectural Design, Pion, 1986.
4) Gero, J. and Fujii.H., A computational Framework forConcept Formation for a Situated Design Agent,
Knowledge-Based Systems, 13(6), 2000.
5) Bratman, M. E., Intention, Plans, and Action, Harvard
University Press, 1987.
6) P. Müller, P. The Design of Intelligent Agents, Springer,
1991.
7) Proposed by Bertrand Arthur William Russell8) https://www.britannica.com/topic/philosophy-of-mind/
Propositional-attitudes
9) Anscombe, G.E.M., Intention, Oxford, Basil Blackwell,1957 – 2nd Edition, 1963.

as a by-product. In the case that E0 is not predicted inadvance when the action is intended, it could be said that thesituation that renders proposition E0 true is noticed by

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