• Proceedings of the KSME Conference
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• 2001.06e
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• pp.317-322
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• 2001

This study depicts an experimental work of the impulsive wave discharged from the open end of several kinds of right-angle bend pipes, which are attached to the open end of a simple shock tube. The weak normal shock wave with its magnitude of Mach number from 1.03 to 1.20 is employed to obtain the impulsive wave propagating outside the open end of the bend pipes. The experimental data of the magnitude of the impulsive wave and its propagation directivity are analyzed to characterize the impulsive waves discharged from the right-angle bend pipes and compared with those from a straight pipe. The results obtained show that a right-angle miter bend considerably reduces the magnitude of the impulsive wave and its directivity toward to the pipe axis, compared with the straight pipe. It is believed that the right angle miter bend pipe can playa role of passive control against the impulsive wave.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.21 no.9
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• pp.1095-1104
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• 1997

When a high-speed railway train enters a tunnel, a compression wave is generated ahead of the train and propagates along the tunnel, compressing and accelerating the rest air in front of the wave. At the exit of the tunnel, an impulsive wave is emitted outward toward the surrounding, which causes a positive impulsive noise like a kind of sonic boom produced by a supersonic aircraft. With the advent of high-speed train, such an impulsive noise can be large enough to cause the noise problem, unless some attempts are made to alleviate its pressure levels. For the purpose of the impulsive noise reduction, the present study investigated the effect of a vertical bleed duct on the compression wave propagating into a model tunnel. Numerical results were obtained using a Piecewise Linear Method and testified by experiment of shock tube with an open end. The results showed that the vertical bleed duct reduces the maximum pressure gradient of compression wave front by about 30 percent, compared with the straight tunnel without the bleed duct. As the width of the vertical bleed duct becomes larger, reduction of the impulsive noise is expected to be greater. However the impulsive noise is independent of the height of the vertical bleed duct.

• Journal of Institute of Control, Robotics and Systems
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• v.20 no.11
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• pp.1136-1141
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• 2014

This paper proposes a new contact type ball tracking sensor to improve the control performance of a low cost ball-and-beam system. It is well-known that the impulsive measurement noise contained in ball position measurement is one of the factors which severely degrades the ball-and-beam control performance. The impulsive ball position measurement noises often appear under the sporadical ball floating on the beam. This fact motivates us to devise a simple analog preprocessing circuit to determine whether the ball loses the contact or not. Once the abnormal ball position measurement is detected, the design problem of the ball tracking sensor can be cast into the typical state estimation problem with missing data. In order to tackle the real-time implementation issue, a steady-state Kalman filter is applied to the problem. Through the experimental results, the usefulness of the proposed scheme is demonstrated.

• Bulletin of the Korean Mathematical Society
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• v.37 no.2
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• pp.229-247
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• 2000

This paper is concerned with the impulsive Cauchy problem where the control function u is a possibly discontinuous vector-valued function with finite total variation. We assume that the vector fields f, $g_i$(i=1,…, m) are dependent on the time variable. The impulsive Cauchy problem is of the form x(t)=f(t,x) +$\SUMg_i(t,x)u_i(t)$, $t\in$[0,T], x(0)=$\in\; R^n$, where the vector fields f, $g_i$ : $\mathbb{R}\; \times\; \mathbb{R}\; \longrightarrow\; \mathbb(R)^n$ are measurable in t and Lipschitz continuous in x, If $g_i's$ satisfy a condition that $\SUM{\mid}g_i(t_2,x){\mid}{\leq}{\phi}$ $\forallt_1\; <\; t-2,x\; {\epsilon}\;\mathbb{R}^n$ for some increasing function $\phi$, then the imput-output function can be continuously extended to measurable functions of bounded variation.

• Journal of the Korean Home Economics Association
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• v.39 no.9
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• pp.175-188
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• 2001

The purpose of this study was to examine the relationships between child's self-regulation and stress according to child's sex. The subjects for this study were 380 children of 5-6th grade selected from elementary schools in Busan. Lee, Soon-Kyu's questionnaires(1994) on child's self-regulation and Han, Mi-Hyun's questionnaires(1996) on child's stress were used. Statistical techniques such as Manova, Pearson's correlation, multiple regression, canonical were used. The resets were as follows : (1) According to sex, there were significant differences in child's self-regulation and stress. The girls showed more self-regulation and higher friend-related stress than the boys. The boys showed higher parent-related stress than the girls. (2) Relationships between child's self-regulation and stress showed as follows : The boys who used more impulsive-control perceived lower friend-related stress, lower school-related stress, lower teacher-related stress, and lower surroundings-related stress. And the boys who used more behavioral-control perceived lower school-related stress, lower teacher-related stress, and lower surroundings-related stress. (3) The predicted variable for boy's friend-related stress was impulsive-control. The predicted variables for boy's school-related stress, teacher-related stress and surroundings-related stress were impulsive-control and behavioral-control. (4) Among three dimensions of self-regulation for boy, the effective variables were impulsive-control and behavioral-control. And among six dimensions of stress were surroundings-related stress, school-related stress and friend-related stress. Implications of this study were discussed in terms of child's self-regulation and stress.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.11 no.9
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• pp.406-413
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• 2001

The current study depicts and experimental work of the impulsive wave discharged from the exit of several kinds of right-angle bend pipes, which are attached to the open end of a simple shock tube. The weak normal shock wave with Mach number from 1.02 to 1.20 is employed to obtain the impulsive wave propagating outside the exit of the pipe bends. The experimental data of the magnitude of the impulsive wave and its propagation directivity are analyzed to characterize the impulsive waves discharged from the right-angle bend pipes and compared with those from a straight pipe. The impulsive waves are visualized by a Schlieren optical system. A computation work using the two-dimensional, unsteady, compressible Euler equation is also carried out to represent the experimented impulsive waves. The results obtained show that a right-angle miter bend considerably reduces the magnitude of the impulsive wave and its directivity toward to the pipe axis, compared with the straight pipe. It is believed that the right angle miter bend pipe can play a role of passive control agianst the impulsive wave.

• Bulletin of the Korean Mathematical Society
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• v.37 no.1
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• pp.37-52
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• 2000

This paper is concerned with the impulsive Cauchy problem (equation omitted) where u is a possibly discontinuous vector-valued function and f, $g_{i}$ : $IR^{n}$ -> $IR^{n}$ are suitably smooth functions. We show that the input-output map is Lipschitz continuous and investigate compactness of reachable sets.

• Journal of the Korean Society of Costume
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• v.51 no.7
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• pp.49-62
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• 2001

The purposes of this study were to find out the catalogue and online-order apparel shoppers' impulsive purchase orientation and impulsive purchase stimuli. Self-administered questionnaires were distributed to women over than 20 years, and collected from middle to the end of November in 2000. Frequencies, percentages, and mean were calculated. One-way ANOVA, chi-square test, factor analysis, and cluster analysis were used, and Duncan's Multiple Range test was followed. 1. Factors of impulsive purchase orientation were relax from negative moods, design property, inducement from neighbors, taste congruence, price property of apparel, positive moods, and loose-control, and were segmented into the low impulsive purchaser, the reasonable purchaser, the fulfilled with positive moods, and the high impulsive purchaser. The factors of impulsive purchase stimuli were apparel property, consumer service, sales promotion on the point of sales, and low price. 2. The low impulsive Purchaser was affected little by impulsive purchase stimuli, spent a little money on apparel, and the married with high education level were the most. The reasonable purchaser was affected by sales promotion on the point of sales or low price, spent a little money on apparel, and students or house-wives were the most The fulfilled with positive moods was affected by low price, and students or career women with high education level were the most, but spent less money on apparel. The high impulsive purchaser was affected by various impulsive purchase stimuli, the young unmarried with high education level were the most, and spent more money on apparel. 3. The younger, the unmarried, students or career women, and shoppers with higher income or apparel expenditure showed a higher impulsive purchase tendency for relax from negative mood, design property, for inducement from neighbor, taste congruence, and positive moods. 4. The older, the married, house wives, and shoppers with higher apparel expenditure were stimulated by apparel property or consumer services.

• Journal of the Korean Mathematical Society
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• v.37 no.5
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• pp.793-803
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• 2000

An impulsive semilinear parabolic equation subject to Robin boundary condition is considered. We prove that for certain classes of impulsive sources and continuous initial data, the solutions of the problem under consideration blow up in the desired time interval.

• 제어로봇시스템학회:학술대회논문집
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• 1990.10b
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• pp.896-901
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• 1990

A simulation analysis is presented for the position control of a single-link flexible manipulator whose end-effector is subjected to an impulsive force. Arm is rotated by a d.c. servomotor at the shoulder so that the end point stays precisely at its initial position even if the end effector is thumped with the impulsive loading. A gap sensor is used to measure the tip displacement. The control torque based on the PD control law is applied to the motor through the driver circuit. The control strategy is tested by means of computer simulation for the one-link flexible-arm prototype in the authers' laboratory at Tohoku Univ.