• Transactions of the Korean Society of Mechanical Engineers
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• v.19 no.1
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• pp.132-141
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• 1995

The torque converter, an important component of automatic transmissions, is a hydrodynamic device which has a great influence on transient characteristics of vehicle during shift. To predict the accurate driving performance in extremely transient state such as shifting process, a detailed analysis of the torque converter is required. In this study, one dimensional performance model of the torque converter based on the concept of mean flow path, was used to analyze the shifting transients and the exact values of equivalent parameters were determined from the experimental results by using BOX program. The dynamic modelings of the components of power transmission systems such as engines, planetary gear systems, clutches and one-way clutches, were carried out. To analyze the shifting transients of tracked vehicle, a simulation program was developed. In the modeling of power transmission systems, the stiffness of shafts was neglected and shifting control logic(TCU) was included. Using the developed simulation program, the driving conditions were simulated and the results of simulation were verified through the experiments on the dynamometer.

• Journal of Biomedical Engineering Research
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• v.18 no.4
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• pp.413-420
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• 1997

In this paper, we analyzed the contraction patterns of active elbow muscles during isometric, concentric and eccentric contraction. The analysis parameters consist of frequency domain parameters (mean frequency, median frequency, peak frequency, peak power, skewness, kurtosis) and time domain paraseters (zero crossing, positive maxima, integrated EMG). The results of this study were as follows; The BR/BB of isometric contraction appeared to be Venter as the elbow joint was more extended. The BR /BB during concentric and eccentric contraction tended to increase with more extension of the elbow joint angle, but there was no significant difference between concentric and eccentric contraction. Further, the EMG power spectrum due to the type of contraction were different betwen eccentric and concentric contraction. According to the results, it was found that the activation pattern in elbow flexor muscles was different during three different muscle contraction pattern. Therefore, elbow flexor muscles should not be considered a single functioning unit. Especially, at the time domain analysis, IEMG is a dominant parameter for analysis of activation patterns, and the skewness kurtosis can be useful parameters in functional recognition for prosthesis control purpose.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.27 no.5
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• pp.605-612
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• 1994

The methods to determine the hydrodynamic coefficients for the fixed type artificial reefs which were constructed to control ecological system in coastal waters are compared and discussed by model test results. To calculate the wave forces, least square method show good agreement with the experimental results and more stability than maximum force component method or Fourier decomposition method. This modified least square method of weighting the square of measured force turned out to be the most feasible method for maximum force. Using the feasible method, hydrodynamic characteristics for artificial reefs on uniform slopes offshore and breaking zone were studied. They were properly related to Keulegan-Carpenter's number and found larger than previous results. Wave force coefficients for artificial reefs around breaking zone were distributed from 1.5 to 2.5, and the mean value was 2.0. Drag force components were more in evidence than inertia force in maximum force which is important parameter to evaluate stability for high-permeability structures. A formula for the calculation of the maximum force for artificial reefs design is proposed, using structural dimension, water particle velocity and Keulegan-Carpenter's number.

• Journal of Fisheries and Marine Sciences Education
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• v.19 no.2
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• pp.161-167
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• 2007

It is necessary to control the room temperature for comfortable and deep sleep during a tropical night. We need to investigate thermal transport and parameter between human and environment for comfortable sleep. Therefore this study is performed to evaluate the comfortable room temperature based on the change of skin temperature under variations in thermal conditions and several reports. Five female subjects of 20~22 years with similar sleeping pattern were participated for the experiment. The subjects arrived in chamber at 9 pm and adapted to thermal circumstances during 2 hours. The sensors was sticked in body for skin temperatures. If subjects fall asleep in chamber, lights off and then sleep during 8 hours.As results, indoor temperature range for comfort sleep was $23.9{\sim}28.4^{\circ}C$ based on comfort mean skin temperature. But considering transition of time, minimum indoor temperature was $21.6^{\circ}C$, $22.9^{\circ}C$, $24.1^{\circ}C$, $23.9^{\circ}C$ and maximum indoor temperature was $28.2^{\circ}C$, $30.1^{\circ}C$.

• Proceedings of the KSR Conference
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• 2004.10a
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• pp.467-471
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• 2004

The development of a tilting train with construction of electric line on the conventional railway is required for speed-up on the conventional railway with many curving sections. For development of tilting train, the study and development of the tilting system and tilting bogie having the different mechanism with a general high speed train will play a main role for improving the technology in the field of Korean railway. The study and development of the pantograph tilting mechanism in order to keep a good contact behavior between a pantograph and a contact wire by tilting a pantograph on the opposite direction of the vehicle tilting direction. In this study, we analyzed the aerodynamic characteristic of a developing pantograph on the tilting train and obtained the contact force with catenary by aerodynamic lift force by the aerodynamic analysis. We also performed the numerical analysis for design the device controlling lift force on a pantograph. From the aerodynamic simulation and parameter study for a device to control the lift force, we will suggest the various shape and the optimal shape of it corresponding to a developing tilting pantograph. The Fluent software is used for the calculation of flow profile in this study.

• ETRI Journal
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• v.19 no.3
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• pp.186-201
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• 1997

In this paper, a home location register (HLR) for CDMA mobile communication system (CMS) is introduced. It stores the mobile station (MS) subscribers locations and supplementary service information. Call processing procedures for HLR are developed to receive and store subscriber's location coming from mobile exchange (MX) during the location registration, and to transfer subscriber's location and supplementary service information to the MX during the mobile-terminated call setup. For fast call processing by increasing database access speed, a memory-resident database management system is devised. For Easy and secure HLR operation, administration and maintenance functions and overload control mechanisms are implemented. Designed HLR hardware platform is expandable and flexible enough to reallocated software blocks to any subsystems within the platform. It is configurable according to the size of subscribers. An authentication center (AC) is developed on the same platform. It screens the qualified MS from the unqualified. The calls to and from the unqualified MS are rejected in CMS. To authenticate the MS, the AC generates a new authentication parameter called "AUTHR" using shared secret data (SSD) and compared it with the other AUTHR received from the MS. The MC also generates and stores seed keys called "A-keys" which are used to generate SSDs. The HLR requirements, the AC requirements, software architecture, hardware platform, and test results are discussed.

• Journal of Industrial Technology
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• v.23 no.A
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• pp.83-92
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• 2003

The previous control point surveying, being standardized by trigonometric point which hasn't been unified in the whole country and producing put into operation through complex calculation process, has many problems about accurate results and economic side. Because most of trigonometric points that standardize a present surveying are in situation in top of the mountain, there are many difficulties in solving sight problems. Since trigonometric points are far away from one another, Differences are created because of limitation of point distance, observatory network construction and distribution of error. In the information age, the study about acquiring three dimension surveying information that uses GPS has been processed as fast as acquiring topography information is getting important gradually. For utilizing GPS in surveying work, deciding transformation 7-Parameters that changes data about location information which is received by GPS receiver is important. In this study, it is decided transformation 7-Parameters that can be used in ka-pyoung area by using GPS surveying production that had put into operation.

• Nuclear Engineering and Technology
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• v.37 no.2
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• pp.201-206
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• 2005

Fretting, which is a special type of wear, is defined as small amplitude relative motion along the contacting interface between two materials. The structural integrity of steam generators in nuclear power plants is very much dependent upon the fretting wear characteristics of Inconel 690 U-tubes. In this study, a finite element model that can simulate fretting wear on the secondary side of the steam generator was developed and used for a quantitative investigation of the fretting wear phenomenon. Finite element modeling of elastic contact wear problems was performed to demonstrate the feasibility of applying the finite element method to fretting wear problems. The elastic beam problem, with existing solutions, is treated as a numerical example. By introducing a control parameter s, which scaled up the wear constant and scaled down the cycle numbers, the algorithm was shown to greatly reduce the time required for the analysis. The work rate model was adopted in the wear model. In the three-dimensional finite element analysis, a quarterly symmetric model was used to simulate cross tubes contacting at right angles. The wear constant of Inconel 690 in the work rate model was taken as $K=26.7{\times}10^{-15}\;Pa^{-1}$ from experimental data obtained using a fretting wear test rig with a piezoelectric actuator. The analyses revealed donut-shaped wear along the contacting boundary, which is a typical feature of fretting wear.

• Journal of Korean Biological Nursing Science
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• v.17 no.2
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• pp.179-187
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• 2015

Purpose: This study was done to evaluate the effects of a recreation therapy program on burn rehabilitation patients to determine if the program is an effective nursing intervention which can affect mental health problems and heart rate variability. Methods: Subjects were 54 hospitalized burn rehabilitation patients (25 in the control group, 29 in the experimental group). The experimental group participated 6 times in a recreation therapy program led by a qualified instructor. Brief symptoms inventory-18 (somatization, anxiety, depression) questionnaire, and heart rate variability were checked before and after the recreation therapy program. Results: The mental health scale showed significant differences in somatization (p<.001), anxiety (p<.001) and depression (p<.001). There was no significant difference in heart rate variability (autonomic activity, autonomic balance, stress resistance, stress parameter and fatigue, mean heart rate, electro-cardiac stability). Conclusion: The findings from this study suggest that a recreation therapy program is an effective nursing intervention to decrease the level of mental health problems of burn rehabilitation patients. However, a subsequent study is needed to develop an intervention program that will induce the effect of physiological parameters like heart rate variability (HRV).

• The korean journal of orthodontics
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• v.15 no.1
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• pp.55-66
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• 1985

The study was undertaken to ascertain the speech defect of patients with malocclusion, especially of openbite patients, by means of the spectral analysis method. The experimental group was composed of ten female openbite patients and their mean age was 13.8 yrs. The control group was also composed of ten female girls and their mean age was 13.7 yrs. As for the speech material, eight Korean monophthrongs and two Korean fricatives and two affricatives were used. Speeches were recorded and then analyzed by a Kay 7800 digital sonagraph. Formant frequency level or range was used as a phonemic parameter. The results were as follows: 1. Among Vowels /a:/ : $F_1,\;F_3\;and\;F_1/F_2$ showed abnormality. /o:/ and $/w:/:F_2,\;F_2-F_1\;and\;F_1/F_2$ showed abnormality. 2. Among Consonants /S/ and /h/ : The upper and lower borders of the frequency range showed abnormality. (equation omitted) : The lower border of the frequency range showed abnormality. $/C^{h}/$ : The upper and lower borders of the frequency range and concentration point showed abnormality.