Determining Latent Functions by Focusing on the Purposes of. Products

Transcription

1 5th IADR 03 TKY Determining Latent Functions by Focusing on the Purposes of Products Yuki Murota*, Toshiharu Taura**, Akira Tsumaya*** *Kobe University, ** Kobe University, *** Kobe University, Abstract: A product, when used in a certain field, manifests the nction that is intended by the designer. However, products used in different fields (latent fields may manifest different nctions (latent nctions that may lead to valuable discoveries. From the perspective of product safety and in order to create innovative nctions, it has become increasingly important to consider the fields in which products are used and their potential hidden nctions. This paper discusses and proposes a method for discovering the latent nctions and latent fields of products by focusing on their rposes. If two products share the same rpose, one of the products may be substituted for the other and manifest its visible nction as a latent nction. First, aspects of the rposes of products are discussed and systematized with reference to related studies. Next, a procedure and a comter system to determine latent nctions and their latent fields are created. The authors then conduct a case study using this system, which shows the effectiveness of the proposed method. Key words: Function, Latent Function, Field, Latent Field, Purpose. Introduction Products are designed with consideration of the nction and place in which they will be used. For example, a chair is designed for the nction of sitting on and used with a table in a living room. However, products may also manifest implicit nctions in addition to those that are intended by designers. In the previous example, the chair may be used as a hanger with the nction of hanging clothes, or as a step with the nction of lifting a human higher, if he or she needs to reach for something on a high shelf. In General Design Theory, these types of nctions, which the designers did not originally intend but which may be manifested in another situation, are called latent nctions. In this theory, latent nctions are defined as different nctions that manifest under different circumstances, whereas a nction satisfying the requirements provided by a designer is defined as a visible nction. The circumstances that cause a visible nction are defined as the field [3]. Latent nctions may cause dangerous situations for users. For example, an electric bulb that is normally used to illuminate a room has a nction of lighting up things. However, if a user inadvertently touches it, a latent nction of heating things is actualized and leads to burned hands. Designers are expected to design products so that such harml latent nctions do not appear. n the other hand, latent nctions may add value to products for users. For example, an empty bottle may be used as a pen stand if a latent nction of gathering pens is discovered and may also be used as a flowerpot if a latent nction of planting flowers is discovered. These are examples in which usages are created by actualizing latent nctions. Considering such latent nctions may increase the reuse of products. As described above, latent nctions are usel in the realization of safety manufacturing and sustainable manufacturing. Hence, when designing products, it is important to examine their latent nctions as well as their

2 5th IADR 03 TKY visible nctions. The authors previously focused on the latent nctions that are inherent in products and proposed a method for discovering them (hereafter referred to as latent nction inferring []. The authors thought that the latent nctions of one product are analogized from the visible nctions of another product, if both products have a similar lower-level nction structure. In this paper, the authors propose another method to infer latent nctions and their fields from a different viewpoint. pecifically, the authors focus on the rposes of products to infer the products latent nctions and their fields. This paper is organized into 5 chapters. In Chapter, the authors previous study of latent nction inferring is introduced. In Chapter 3, the authors discuss the rposes of products as a viewpoint for latent nction inferring. The fields in which products are used is also discussed. Based on these discussions, a method of inferring latent nctions on the basis of a product s rpose is proposed. In Chapter 4, based on the method proposed above, a comter system for inferring latent nctions is developed and the effectiveness of the proposed method is verified. Chapter 5 contains the conclusion and areas for rther discussion.. Inferring Latent Function by Focusing on Lower-level Functions When using the above definition of latent nction, it is necessary to identify all of a product s behaviors in order to derive the latent nction. However, this is difficult, particularly when designing complicated products. In addition, nctions are subjectively perceived concepts and vary with the individual user. Moreover, not all behaviors can be considered latent nctions. Therefore, another approach should be developed that does not rely on directly identifying all of a product s behaviors in advance. In their previous study, the authors created the following method to derive latent nctions. Let us consider a car as an example. A car has the latent nction of pressing against the ground. Here, this latent nction can be represented as the nction of road roller. In other words, the latent nctions of a product are analogized from the nctions of other products. n the basis of this consideration, the authors analyzed the kind of relationship that exists between the target and base products in the analogy framework, wherein the nction of the base product can be transferred to the target product []. As a result, it was revealed that the target product (in the above example, a car and the base product (in the above example, a road roller had similar lower-level nctions. In the above example, there was a similarity between engine turns tire, which is a lower-level nction of a car, and engine turns roller, which is a lower-level nction of a road roller. This example suggests that the visible nction of the base product (a road roller can be the latent nction of the target product (a car under the condition that both products are able to be manifest the same nction ( pressing against the ground and that both products contain a similar mechanism to realize it. Conversely, it is assumed that the latent nction can be analogized by referring to a product with a similar mechanism. In the previous study[], a nction was defined as an entity s behavior that plays a special role and described by using a subject (, verb (, and (. In addition, for a visible nction of a product, f = (,,, a latent nction of the same product was defined as a role that appears when the product ( exerts a different action ( on a different (. Accordingly, the operation of nction transfer was proposed as the method to find a latent nction by analogy. As shown in Figure, this operation replaced verb and of the nction f = (,, (hereafter referred to as the target nction with verb and of some other nction f = (,, (hereafter referred to as the base nction. This method focused on the similarity between the products lower-level nctions, breaking the nction down into its individual details rather than by examining the nctions that were observed for the product as a whole. f (,, f (,, f (,, Figure. Function transfer

3 5th IADR 03 TKY 3. Inferring Latent Function by Focusing on the Purpose of Products 3.. New approach to latent nction inferring Usually, products are designed to achieve a particular rpose. For example, a car is designed for the rpose of moving s or humans, and a car manifests a nction of carrying s or humans to achieve this rpose. The authors thought that latent nctions could be analogized by focusing on the rposes for which products are used as well as by focusing on the similarity of lower-level nctions. Let us consider the example of a mowing machine and burner. To cut grass that grows in a yard, we use a mowing machine that manifests the nction of cutting the grass. However, a burner which has the original nction burn s can be substituted for this rpose. This substitution is possible because the rpose of both nctions is to remove an, and therefore the same result is expected. Accordingly, a burner is considered to have the latent nction burn grass in the yard. This example implies that a product may be substituted for another product and manifest the latent nction as a visible nction in another product s field if it shares the same rpose. 3.. Purpose of products 3... Consideration of the rposes of products To clarify the rpose of a product and how the rpose is described, the authors refer to the discussion of the relationship between rpose and means in teleology. In teleology, rpose is defined as that which is achieved by means. This implies that a causal connection exists between rpose and means. In this study, the authors extend this discussion by considering that the rpose of a product is the result after the nctions manifest and the nctions of a product are the means to achieve the rpose. Next, let us consider how the rpose of a product is described. The rposes of products are usually described as the actions for which people use products. This can be explained by using the examples of oven and mixer. The nctions of oven and mixer are described as oven bake food and mixer mix food respectively by using a set of subject (, verb (, and (. Here, the rpose of both oven and mixer is to cook food, which is the result after the nctions have manifested. Then, the rpose is said to be that which is generated after the nctions are manifested. This consideration implies that rposes are not actions that are abstracted from the nctions. For example, the nctions of kitchen knife and chainsaw are described as kitchen knife cuts food and chainsaw cuts wood. According to the previous definition, the rposes of these products are to cut s, which is an abstraction of each nction. However, we should notice that the kitchen knife is used in order to cook food and the chainsaw is used in order to create s, actions that can be achieved after each nction has manifested. Accordingly, the authors believe that they should pay attention to the action that becomes possible after the nctions are manifested Definition of the rposes of products n the basis of the above consideration, the authors define the rposes and nctions of products as follows. Purpose of product: The rpose of a product is the action that people want to complete by using the product and is described by a set of a verb ( and an ( Function: The nction is the means to achieve the rpose and is described by a set of a subject (, verb (,and an (. The relationship between nction and rpose is as follows:

4 5th IADR 03 TKY The rpose of a product is the result after the nctions have manifested. Function, =(,,, and rpose, =(,, have the following relationships: or For example, the rpose and nction of a clothes washer are described as clean and a clothes washer washes clothes Fields Consideration of fields Latent nctions are those that are manifested under different circumstances, as introduced in section. This statement implies that we should focus on circumstances in order to find the latent nctions. This study uses the term fields in order to capture the notion of the circumstances of products. Here, the authors would like to discuss how fields are defined and what kinds of fields exist. Let us consider an example of an electric bulb. The visible nction of an electric bulb is electric bulb lights up things, and this nction is manifested under the condition that there exist people who manilate the electric bulb, there exists the place where an electric bulb is used, and there exists an to light up. These existences are strongly related to fields Definition of fields n the basis of the above consideration, we define the fields as follows: Fields: Fields are the circumstances that cause the nctions to manifest. The fields are classified into person who uses products, of nction, and place where the products are used. isible nction and latent nctions are defined as follows: isible fields: The field (A in which the visible nction (a is manifested. Latent fields: The field (B in which the other different (latent nction (b is manifested by the same product. The relationship between visible nction, latent nction, visible field, and latent field is illustrated in Figure. Figure. Relationship between visible/latent nction and visible/latent field

5 5th IADR 03 TKY (,, (,, fi ( X, Y fi ( X, Y Figure.3 Function transfer 3.4. Process of inferring latent nction by focusing on the rpose of a product Consideration of nction transfer by focusing on the rpose of a product Let us consider how the nction is transferred when the rposes of products are focused on. In the authors previous study, nction transfer is defined as replacing verb and of the target nction f = (,, with verb and of some other base nction f = (,,. However, when we focus on the rposes of products, the previous method cannot be applied. This can be explained with the example of mower and burner. Here, the target product is mower and the base product is burner ; the nctions are mower cuts grass and burner burns respectively; and the rpose of both products is remove. If the rpose burn is transferred from the burner to the mower according to the previous method, the latent nction mower burns is obtained, but this nction is inappropriate in common-sense terms. This is because the similarity between the lower-level nctions of the target and base product, the condition in the previous method, is not valid. Accordingly, in this study, a latent nction is inferred by replacing only the. Furthermore, the fields (latent field are also inferred. Function transfer: By focusing on the rposes of products, the authors conclude that nction transfer involves replacing the of a target product s visible nction, = (,,, which is manifested, and visible fields, fi = (X,Y, with of the base product s visible nction, = (,,, and the fields (latent field, fi = (X,Y. Here, X is a person who uses the products; Y is a place where products are used. This process is illustrated in Figure 3. (,, fi ( X, Y Formulation of the latent nction inference process The latent nction inference process, which uses the similarity in the rposes of products for nction transfer, is formulated as follows: l : P p P { p, p fi ( ( X (,, when p fi l l( P ( ( ( X }, p,,, (, Y, fi ( X, Y, Y, (,, fi, (, fi,,, p, (,, fi, Here, P denotes the target product (p and base product (p, denotes the rpose of p, denotes the rpose of p, denotes the latent nction of the target product (p, and fi denotes the latent fields (

6 5th IADR 03 TKY corresponding to. An example is presented in Figure 4. Here, remove, which is the rpose of the burner, and remove, which is the rpose of the mower, are found to be same. Accordingly, grass, in the visible nction of mower, and its visible field, adult, yard, are transferred to burner. As a result, the latent nction burner burns grass and the latent field adult, yard are obtained. 4. Development of Comter ystem for Latent Function Inferring Based on the method proposed above, the authors developed a comter system for inferring latent nctions. In addition, a product database containing the visible nction, visible fields, and rpose of 8 products was prepared. In this system, following the int of the target product by the user, a product s latent nctions can be inferred. In order to confirm the feasibility of the proposed method and developed comter system, the authors conducted an experiment. In this experiment, the latent nction burner burn grass and its latent field adult, yard, which was illustrated as an example in the previous section, could be inferred. Furthermore, another case study was conducted, as shown in Figure 5. In this case study, electrical toothbrush was first selected as a target product and dish washer was selected as a base product. Next, the rposes of both products were found to be same. Accordingly, that latent nction electric toothbrush brushes dish and its latent fields person, kitchen were inferred by nction transfer from the visible nction dish washer washes dish and its visible field person, kitchen. The latent nction electrical toothbrush brushes dish could not be inferred through the previous method, because the lower-level nctions of the two products were not the same. In another case study, the latent nction air-gun fires water of an air-gun and its latent field child, outdoors were inferred (Figure 6. Although the latent nction air-gun fires water is difficult to understand, its latent fields ( child, outdoors suggest its usage. The latent nction electrical toothbrush brushes dish and its latent fields person, kitchen suggest values or uses for an electrical toothbrush. Meanwhile, the latent nction air-gun fires water and its latent fields child, outdoors show an incorrect use of an air-gun by a child. This information can help a designer design more innovative and safer products if it is presented in advance. These results show the effectiveness of the proposed method. p : burner remove match remove p : mower burner burns mower cuts grass X Y adult outdoor transfer X Y adult yard Infer,fi The latent nction and fields of burner are inferred as = (burner, burns, grass fi = (adult,yard Figure.4 Example of latent nction inferring

7 5th IADR 03 TKY p : electrical toothbrush match p : dish washer clean clean X Y electrical toothbrush brushes tooth all people lavatory transfer X Y dish washer washes dish woman kitchen f Infer upper,fi The latent nction and fields of electrical toothbrush are inferred as = (electrical toothbrush, brushes, dish fi = (woman, kitchen Figure.5 Inferring latent nctions of electrical toothbrush p : air-gun enjoy oneself match enjoy oneself p : water-gun air-gun fires ball bullet water-gun fires water X Y adult outdoor transfer X Y child outdoor f Infer upper,fi The latent nction and fields of air-gun are inferred as = (air-gun, fires, water fi = (child, outdoor Figure.6 Inferring the latent nctions of air-gun 5. Conclusion In this study, the authors proposed and formulated a method for inferring a product s latent nction by focusing on the notions of rpose of products and fields. Based on the proposed method, the authors developed a comter system for inferring latent nctions. From the results of case studies, the authors confirmed the effectiveness of the proposed method. However, some inappropriate latent nctions may still be created. The authors therefore intend to investigate methods for reducing these inappropriate nctions. In addition, the appropriateness of the created latent nctions was evaluated by the authors subjectively. It is necessary to consider criteria for determining this ively. Acknowledgements This work was supported by KAKEN (

8 5th IADR 03 TKY References and Citations [] Minami, K., Taura, T. and Tsumaya, A. (00 A study on modeling of reasoning process considering latent nction, Design and ystems Division Conference of Japan ociety of Mechanical Engineers, Tokyo, Japan, 7-9 ctober. [] Yamamoto, E., Taura, T., Tsumaya, A. and Yamamoto, M. (00 A Method for Function Dividing in Conceptual Design by Focusing on Linguistic Hierarchal Relations, Journal of Comting and Information cience in Engineering, vol. 0, [3] Yoshikawa, H. (98 General design theory and a CAD system, in ata, T. and Warman, E.A(eds. (98 Man-machine communication in CAD/CAM, Amsterdam, North-Holland