• 제어로봇시스템학회:학술대회논문집
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• 2002.10a
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• pp.35.1-35
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• 2002

$\textbullet$ Sliding mode control (SMC) with nonlinear interpolation in variable boundary layer (VBL) is proposed $\textbullet$ A sigmoid function is used for nonlinear interpolation in VBL. $\textbullet$ The Parameter of the sigmoid function is tuned by fuzzy controller $\textbullet$ The choice of parameter for the sigmoid function is guided by FC. $\textbullet$ The parameter is continuously updated as boundary layer thickness varies. $\textbullet$ The proposed method hasbetter tracking performance than the conventional linear interpolation $\textbullet$ To demonstrate its performance the proposed control algorithm is applied to a nonlinear system.

• Proceedings of the Korean Society of Medical Physics Conference
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• 2002.09a
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• pp.222-224
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• 2002

In proton and heavy ion radiotherapy, compensators are required to modify the energy of heavy ion, to compensate the local difference of tumor depth. Conventional compensators have to be created, exchanged, and stored for each patient and for each irradiation directions. A Cylinder Type Liquid Variable Compensator is and is under development. Hexagonal cylinders will be arranged in honeycomb structure. In which air and fluid are divided by hexagonal pistons. The position of each piston will be changed in each cylinder for adjusting the thickness of fluid for variable compensator. The location of each hexagonal piston is determined by each controlling cylinder connected to the hexagonal cylinder by inlet pipes of fluid. Each controlling cylinder includes controlling a piston, which is moved mechanically. Each controlling cylinder is to be moved by a motor driven by a computer.

• Structural Engineering and Mechanics
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• v.62 no.5
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• pp.587-593
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• 2017

The objective of this analytical study is to calculate the elasto-plastic stresses of Functionally Graded (FG) hyperbolic disc subjected to uniform temperature. The material properties (elastic modulus, thermal expansion coefficient and yield strength) and the geometry (thickness) of the disc are assumed to vary radially with a power law function, but Poisson's ratio does not vary. FG disc material is assumed to be non-work hardening. Radial and tangential stresses are obtained for various thickness profile, temperature and material properties. The results indicate that thickness profile and volume fractions of constituent materials play very important role on the thermal stresses of the FG hyperbolic discs. It is seen that thermal stresses in a disc with variable thickness are lower than those with constant thickness at the same temperature. As a result of this, variations in the thickness profile increase the operation temperature. Moreover, thickness variation in the discs provides a significant weight reduction. A disc with lower rigidity at the inner surface according to the outer surface should be selected to obtain almost homogenous stress distribution and to increase resistance to temperature. So, discs, which have more rigid region at the outer surface, are more useful in terms of resistance to temperature.

• The Journal of Korean Physical Therapy
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• v.29 no.2
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• pp.69-73
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• 2017

Purpose: This study was conducted to investigate the effects of blood flow restriction and different support surfaces for bridge exercises on the thickness of the transverse abdominis and multifidus, which are trunk-stabilizing muscles. Methods: The study's subjects were 45 adults who were divided into three groups that performed bridge exercises over a six-week period on their respective support surfaces after blood flow restriction. Changes in the thickness of the subjects' transverse abdominis and multifidus muscles were measured using ultrasonography before the experiment, then three and six weeks after the experiment. The changes in each variable over time were analyzed using a repeated-measures analysis of variance (ANOVA). Results: The transverse abdominis showed significant differences in muscle thickness with regard to time and the interaction between time and each group (p<0.05), but no significant differences with regard to changes among groups (p>0.05). The multifidus showed significant differences in muscle thickness with regard to time, the interaction between time and each group, and changes between groups (p<0.05). Conclusion: Blood flow restriction and different support surfaces for bridge exercises led to significant differences in the thickness of the transverse abdominis and multifidus. This study's results may be used as the basis for future studies and for rehabilitation in clinical practice.

• Transactions of the Korean Society of Mechanical Engineers
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• v.18 no.3
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• pp.707-715
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• 1994

This study presents thickness optimization for the pressure vessel domes subject to internal pressure and axial force simultaneously. The considered typical pressure vessel domes are ellipsoidal and tori-spherical domes with skirt and nozzle part. These pressure vessel domes under loading have higher stress concentration on geometric discontinuity parts. Therefore, thickness optimization of axi-symmetric pressure vessel domes is essentially concerned on minimizing this stress concentration. The objective function is minimization of weight of pressure vessel dome. The design variable is thickness of dome and cylinder. Considered constraint is Von Mises equivalent stress. In the optimization procedure, ANSYS code is used. The equivalent and hoop stress of original shape domes are compared with those of optimal shape domes. And optimal thicknesses for pressure vessel domes are presented.

• Journal of the Korean Graphic Arts Communication Society
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• v.20 no.2
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• pp.19-30
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• 2002

Four screen mesh counts of 100, 150, 200, and 305 threads per inch are chosen and a designed test figure is exposed on them for printing experiment to measure the ink deposit thickness. Among a number of variables, the ink viscosity, the screen gap and the squeegee pressure and speed are estimated with their effected thickness. These variables affect as much as around 50% compared with the theoretical ink volume listed by the mesh manufacturer and each variable has different influence on the thickness. The data and graphs have been analyzed for the thick film production.

• Structural Engineering and Mechanics
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• v.4 no.5
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• pp.541-552
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• 1996

This paper is concerned with the structural optimization problem of maximizing the compressive buckling load of orthotropic rectangular plates for a given volume of material. The optimality condition is first derived via variational calculus. It states that the thickness distribution is proportional to the strain energy density contrary to popular claims of constant strain energy density at the optimum. An engineers physical meaning of the optimality condition would be to make the average strain energy density with respect to the depth a constant. A double cosine thickness varying plate and a double sine thickness varying plate are then fine tuned in a one parameter optimization using the Rayleigh-Ritz method of analysis. Results for simply supported square plates indicate an increase of 89% in capacity for an orthotropic plate having 100% of its fibers in $0^{\circ}$ direction.

• Journal of the Korean Society of Safety
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• v.6 no.1
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• pp.5-13
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• 1991

Fail-safe design of machine elements or structural members is very aim of the whole mankind. Fracture occurs generally from cracks that exist originally or produced from flaws. The most important job we have to do is to make stopping or decreasing the crack growth rate. For fail-safe design variable thickness plates have been used as structural members in practical engineering services. In this paper, optimum design of CT type plate with varlng thickness is studied with the theoritical analysis. The theoritical analysis was based on the stress concentration and nominal stress analysis. From the study, the optimum design curve was determined for use of designing of such structures using the computer analysis program of optimum design.

• Journal of the Korean Society for Precision Engineering
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• v.14 no.5
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• pp.150-156
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• 1997

Three dimensional finite element analysis was conducted to estimate the effect of shape parameters (plate width and thickness) on the stress intensity factor for crack in the integrally stiffened plate. Analysis was done for width ratios of 0.5, 0.75, 1.0, 1.5, 2.0, 2.5, and thickness ratios of 2, 3, 4, 6. Based on these results, an empirical equation of geometry factor is formulated as a function of crack length and thickness ratio.

• Asian-Australasian Journal of Animal Sciences
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• v.3 no.4
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• pp.263-267
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• 1990

The fat thicknesses of twenty-eight Japanese Black beef steers were measured with an ultrasonic device at eleven points on the cattle prior to slaughter and side dissection. The relation between live fat thickness and both weight and percentage of fat and lean in the carcass was examined. Fat thickness obtained from nine points of the chest, flank and rump regions was found to relate significantly (P<0.01) to both weight and percentage of fat. However, shoulder fat thickness measurements were not significantly related to the weight or percentage of fat or lean in the carcass. Addition of live fat thickness to animal age or live weight as an independent variable markedly improved the precision of multiple regression equations for predicting weight of fat and lean, and percentage of fat. In predicting the percentage of lean, both animal age and body weight were not employed in the multiple regression equation. The residual standard deviation for predicting percentage of fat and lean were 1.93 and 1.87, respectively. The ultrasonic measurement of fat thickness if supposed to be useful to the prediction of carcass composition of beef cattle.