Hiroshi Kawaharada

Part Agent Advice for Promoting Reuse of the Part Based on Life Cycle Information

In order to promote reuse of parts for achieving sustainable society, we are developing part agent system. A part agent that consists of a network agent and radio frequency identification technologies manages information of the corresponding part throughout its life cycle and provides users with advices on maintenance of the part. In this paper, a framework is proposed to create appropriate advices based on life cycle information of the part. To be used in the framework, a method was developed to estimate reusability of a part against operations of a user based on causal network on failures.

Quadrilateral mesh fitting that preserves sharp features based on multi-normals for Laplacian energy

Because the cost of performance testing using actual products is expensive, manufacturers use lower-cost computer-aided design simulations for this function. In this paper, we propose using hexahedral meshes, which are more accurate than tetrahedral meshes, for finite element analysis. We propose automatic hexahedral mesh generation with sharp features to precisely represent the corresponding features of a target shape. Our hexahedral mesh is generated using a voxel-based algorithm. In our previous works, we fit the surface of the voxels to the target surface using Laplacian energy minimization. We used normal vectors in the fitting to preserve sharp features. However, this method could not represent concave sharp features precisely. In this proposal, we improve our previous Laplacian energy minimization by adding a term that depends on multi-normal vectors instead of using normal vectors. Furthermore, we accentuate a convex/concave surface subset to represent concave sharp features.

Promoting Reuse of Mechanical Parts Using Part Agents

To realize the effective part reuse required for a sustainable society, part agent that is a combination of network agent and RFID is being developed to manage an individual part throughout its life cycle. It forms a product-service system that gives users advices on maintenance. Methods using part agents are developed to promote the reuse of parts: they are, use of user’s preferences that are acquired via questionnaire, distribution of reused parts through a market system and support of decision making on use of reused parts with deterioration. Remaining issues to realize reuse of parts are also discussed.

A Life Cycle Simulation for Part Agents that Proposes a Management of Parts Based on Consumer’s Satisfaction

Management of individual parts throughout their life cycle is required to promote the reuse of parts. A part agent system is proposed and is being developed for this purpose. In this paper, a scheme is proposed so that part agent proposes the replacement of parts taking consumer’s satisfaction into account. To evaluate consumer’s satisfaction, consumer preferences are extracted based on the questionnaire and are implemented in part agent system. Life cycle simulation for parts and part agents is performed to show the effect of the scheme.

Compression of Arbitrary Mesh Data Using Subdivision Surfaces

This paper proposes a new method for mesh data compression. In this method, the original mesh is fitted by a subdivision surface. Thus, our method approximates irregular meshes to semi-regular meshes. The volume bounded by the mesh data is first partitioned into star-shaped volumes, and then each star-shaped volume is approximated. For the approximation we establish a nearly one-to-one correspondence between the resulting vertices of the subdivision surface and the vertices of the original mesh using rays emanating at a kernel point, and fit the surface by the least square method. The resulting approximated data preserves rough shape of the original mesh. Our method can be considered as an approach to a multiresolution mesh. Moreover, our method has advantages for interactively deformed meshes.

Simulations on Wear of a Reused Part that Consider Deviation of Product's Motion due to Deterioration of the Part

To promote the reuse of parts for sustainable society, estimation of deterioration of reused parts is required. For that purpose, we propose a simulation for estimating deterioration of parts that takes into consideration deviation of load caused by deviation of part shape. Preliminary results of the simulation are shown.

Computation of normals for stationary subdivision surfaces

This paper proposes a method for computing of normals for stationary subdivision surfaces. In [1, 2], we derived a new necessary and sufficient condition for Ck-continuity of stationary subdivision schemes. First, we showed that tangent plane continuity is equivalent to the convergence of difference vectors. Thus, using “normal subdivision matrix” [3], we derived a necessary and sufficient condition of tangent plane continuity for stationary subdivision at extraordinary points (including degree 6). Moreover, we derived a necessary and sufficient condition for C1-continuity. Using the analysis, we show that at general points on stationary subdivision surfaces, the computation of the exact normal is an infinite sum of linear combinations of cross products of difference vectors even if the surfaces are C1-continuous. So, it is not computable. However, we can compute the exact normal of subdivision surfaces at the limit position of a vertex of original mesh or of j-th subdivided mesh for any finite j even if the surfaces are not regular.