Fumihiro Suzumura

Closed-loop Stackelberg strategies for singularly perturbed systems: the recursive approach

Abstract The recursive reduced order algorithm in the context of linear closed-loop Stackelberg strategies for singularly perturbed systems is presented. Motivated by previous results for the weakly coupled linear quadratic Nash games, it is shown that a similar algorithm can be produced for singularly perturbed linear quadratic Stackelberg games and the fixed point method is very effective in this case also. It is shown that the proposed recursive algorithm improves the accuracy of the sought solution, that is, the singularly perturbed recursive algorithm converges with the rate of convergence of accuracy O(e). Since all results on linear closed-loop Stackelberg game problem for the singularly perturbed systems can be obtained as far with an accuracy O( e) only, that represents a significant improvement. In order to demonstrate the effectiveness of the proposed algorithm and the failure of the O( e) theory, a numerical example is shown.

XPS Analysis and Atomic Force Microscopy Observation of Micro-Liquids Adsorbed on Pure Iron and Copper Surfaces

The adsorptive on pure iron and copper surfaces was investigated with angle resolved X-ray photoelectron spectroscopy (ARXPS) and atomic force microscope (AFM). Organic species and a little amount of water (micro-droplets surrounded with nanometer-scale film-like-domains) were detected on the oxidized and/or hydrated metallic surfaces for both specimens and their minute structures were discussed.

A MORPHOLOGICAL STUDY OF THE SCAPHOID USING A MATHEMATICAL TECHNIQUE AND COMPARATIVE STUDY OF THE THREE-DIMENSIONAL MEASUREMENTS OF THE SCAPHOID

To guide reconstruction of scaphoid non-union, we attempted to create full-scale models of the scaphoid by three-dimensional computed tomography (3D CT) of the healthy side. In this study, we obtained 3D scans of 51 cadaveric hands and studied the difference in morphology between genders and between the left and right sides. The major axis length on a fixed plane and Fourier transformation curve were examined. Ten scaphoid images were also obtained with 3D CT before and after removal from the cadaveric hands. Our findings suggest good correlation between models produced using 3D CT images of the scaphoid alone, and this could serve as an accurate model if the magnification is corrected using the regression line. However, the model using 3D CT images of the intact wrist joint has a large margin of error and its use will not be practical.

Thermal Deformation Prediction in Machine Tool Model by Using Transfer Functions with Time Delay

The purpose of this paper is to estimate thermal deformation of machine tool model by using transfer function with time delay. The prediction method of thermal deformation based on frequency domain is constructed from transfer function between specified surface temperatures and the relative displacement in cutting area. The relative displacement in cutting area is predicted using two specified surface temperatures near heat source in machine tool model. As a result, the method can be predicted with enough certainty at what rate the temperature changes the most rapidly on machines startup transient behavior. The method proposed in this paper is remarkably effective to estimate thermal deformation and confirm that the error between experimental and estimated values will be remarkably reduced.

DETECTION AND EVALUATION OF DELAMINATION USING ACOUSTIC EMISSION METHOD IN THERMALLY SPRAYED COATING UNDER TENSILE STRESS

AE was measured under a static tensile load for the thermally sprayed ceramic coating in order to investigate the relationship between the detected m-value and the destruction (delamination) of the sprayed coating. This was an effective method to detect and evaluate the delamination of a sprayed coating based on the m-value, because changes of the m-value were closely related in thermally sprayed coatings. Stress level of the delamination analyzed by AE method was almost the same as that predicted by the ESPI method. The generation of delamination was confirmed by cross-section observation of the coating using both stress levels. Therefore, the ESPI method seems to be an effective way to define and evaluate the delamination of sprayed coating determine.

Nondestructive Detection of Delamination of Thermally Sprayed Material Using ESPI

Detection of delamination of a thermally sprayed coating on an SUS304 substrate was carried out nondestructively using electronic speckle pattern interferometry (ESPI) method in both static and cyclic tests at T=298 K and 873 K. Results showed that the surface strain of the coating becomes smaller than that of the substrate when delamination occurs from the interface of the substrate. Two parameters of critical strain of ε c and ε f, which correspond respectively for the static test and the cyclic test, are introduced to evaluate the existence of delamination according to the ε- σ s and ε-N curve. It is considered possible to evaluate the occurrence of delamination in cyclic tests using the static critical strain of ε c, instead of ε f.

Influence of Additives and Hot-Press Sintering on Lipophilic Properties of Silicon Nitride Ceramics

Fe 3 O 4 and Mo and were added to hot-press sintered Si 3 N 4 ceramics to improve their lipophilic and mechanical properties. The bending strength, relative density, hardness and fracture toughness of Si 3 N 4 ceramics with addition of Fe 3 O 4 and Mo were improved by hot-press sintering compared with samples prepared with the pressureless process. In particular, the bending strength and relative density were improved to about 200% and 104%, respectively. Both the macro- and micro-lipophilicity of Fe 3 O 4 - and Mo-added ceramics were improved when prepared with the hot-press process, compared with those prepared with the pressureless process. This can be attributed to the addition of Fe 3 O 4 , and the formation of MoO 3 and Si 2 N 2 O during hot-press sintering. The lower friction coefficient and high wear resistance of Fe 3 O 4 - and Mo-added ceramics have been achieved by applying the hot press process. The high wear resistance is considered to be due to the improvement of hardness and fracture toughness, which decreased the loss of particles during the wear test.

Distributed Processing of Finite-Element Method using Matrix Decomposition. Applied to the Structure of Truss.

The purpose of this study is to achieve decentralized processing of the finite-element method (FEM) by making use of matrix decomposition. For structural analysis of FEM, generally, the global stiffness matrix is a very large matrix which reflects the physical properties of the structure. The matrix decomposition can be used to transpose the global stiffness matrix with simple band matrices. The object of analysis in this study is a truss. The matrix decomposition is effective for the high-dimensional equation which decomposes a reduced-order equation. The computational process with analysis of FEM can be optimized such that the time complexity is minimized due to parallel processing. In this study, the matrix decomposed algorithm is derived for the analysis of a truss, and the time complexity and the arithmetic complexity are compared numerically. Results show that, the time complexity and the arithmetic complexity can be reduced to 29% and 26%, respectively.