• Proceedings of the Korean Geotechical Society Conference
• /
• 2004.03b
• /
• pp.738-745
• /
• 2004

There are a number of ways to reduce the ground vibrations, one of which is by installing underground walls. Model tests for ground vibration have been conducted in recent years, but limited attention has been paid to underground wall which can reduce high vibrations. Up to date, only barriers have been actually installed in dry sand because of many unknown factors subsisting on the behavior of the ground. The characteristics of vibration sources, ground conditions and wall barriers have not been well understood yet, therefore centrifugal modeling was adopted to examine all these characteristics. This paper describes a ball dropping system, which can generate a pulse wave propagation through soil mass, and the test results show the effectiveness of underground wall barrier in reducing mechanical vibration.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.64 no.2
• /
• pp.284-288
• /
• 2015

The color temperature flexibility-typed Lighting Emitting Diode(LED) lighting control system proposed in this thesis employs Pulse Width Modulation(PWM) technique to control the brightness of LED lighting. The LED lighting used as a light source has 20W downlight composed of two types of LED chips: one is Warm White and the other is Cool white. One multi-sensor module consisting an infrared sensor, an illumination sensor, and a temperature sensor was made, to which Bluetooth wireless communication technique was applied to enable a smartphone application to control lighting brightness and identify the information collected from the sensor. CS-1000, a spectroradiometer, was used to measure LED dimming control and the changing values of a color temperature in eight steps. According to a test, it was found that it was possible to change a color temperature from 3187K of Warm White LED to 5600K of Cool White LED.

• The Korean Journal of Rehabilitation Nursing
• /
• v.4 no.2
• /
• pp.155-164
• /
• 2001

Purpose: this study was implemented to develop new nursing intervention, Kyongrak massage, and to examine its effect on chronic pain in elderly women. Method: Kyongrak massage is a manipulation massaging on Kyonghyul site, and Duboo, Kyongchoo, Chucksoo, Hajee, Sangjee Kyongrak massages were used in this study. The subjects(11persons) took Kyongrak massage on head, neck, spinal cord, upper extremities and back lower extremities for 25minutes daily during 5days. The dependent variables were subjective health state, paid, blood pressure, pulse and body temperature. This study was carried out, at 10-12 o'clock, from August 7th, to 22th, 2000. Data were analyzed using frequency, percentage, mean, standard deviation, paired t-test by SPSS PC. Results: subjective health state((t=-3.560, p=.005), body temperature(t=-2.557, p=.029) were increased, and pain level(t=7.884, p=0.000), systolic blood pressure(t=2.923, p=.015) were decreased significantly by Kyongrak massage. Conclusions: The above results have informed us that this Kyongrak massage program(Duboo, Kyongchoo, Chucksoo, Hajee, sangjee) for 25minutes is a useful nursing intervention to decrease chronic pain in each life styles.

• Aerospace Engineering and Technology
• /
• v.3 no.2
• /
• pp.170-176
• /
• 2004

In this study, the relay driver circuit which controls the spacecraft configuration change are implemented and validated. First of all, the specification of the relay driver circuit is defined, and then its circuit meeting the specification defined is designed. In order to verify the design of the relay driver circuit, its circuit was simulated, and then it's confirmed that the relay pulse current and voltage level defined in the specification are obtained, and the results obtained through the functional test of the relay driver circuit are compared and well matched with the simulation results. Also the worst case analysis for confirming the stable operation of the relay driver circuit under the tolerance of each component is performed.

• Journal of the Korean Society of Propulsion Engineers
• /
• v.14 no.1
• /
• pp.1-10
• /
• 2010

Design and performance evaluation of $H_2O_2$ monopropellant thrusters to be used at reaction control of space launch vehicles were presented in this paper. Design thrust level was determined as 100, 250 Newton which is nominal thrust level for commercial space launch vehicles. Qualification thruster models including solenoid valves were developed after the reactor design were evaluated at engineering thruster models. Each thruster was evaluated by measurement of characteristic velocity, thrust, specific impulse, and pulse response times at sea level test condition.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.14 no.1
• /
• pp.155-159
• /
• 2014

In this paper, we describe algorithm and digital circuit implementation of touch screen controller that has the faster response time. We enhance the response time by adaptive search method instead of linear search method of step level in the pulse width decision. The faster response time might bring effects of feeling better in the touch keyboard. The performance of the proposed algorithm and function is verified by using logic simulation and FPGA test board. It is expected to use in the mobile touch screen.

• JSTS:Journal of Semiconductor Technology and Science
• /
• v.15 no.6
• /
• pp.601-607
• /
• 2015

A set of novel silicon controlled rectifier (SCR) devices' characteristics have been analyzed and verified under the electrostatic discharge (ESD) stress. A ring-shaped diffusion was added to their anode or cathode in order to improve the holding voltage (Vh) of SCR structure by creating new current discharging path and decreasing the emitter injection efficiency (${\gamma}$) of parasitic Bipolar Junction Transistor (BJT). ESD current density distribution imitated by 2-dimensional (2D) TCAD simulation demonstrated that an additional current path exists in the proposed SCR. All the related devices were investigated and characterized based on transmission line pulse (TLP) test system in a standard $0.5-{\mu}m$ 24 V CDMOS process. The proposed SCR devices with ring-shaped anode (RASCR) and ring-shaped cathode (RCSCR) own higher Vh than that of Simple SCR (S_SCR). Especially, the Vh of RCSCR has been raised above 33 V. What's more, their holding current is kept over 800 mA, which makes it possible to design power clamp with SCR structure for on chip ESD protection and keep the protected chip away from latch-up risk.

• Proceedings of the KIEE Conference
• /
• 2015.07a
• /
• pp.990-991
• /
• 2015

To drive a magnetron injection gun, thsi paper decribes a design, fabrication and analysis results of proposed compact capacitor charging power supply (CCPS) formed resonant full-bridge inverter for electron gun power supply (EGPS). EGPS needs the -40 kV output voltage and 280 kW output power for few seconds continuously and have to be designed for the rise and fall time to be less than 1 ms with the ripple stability of output voltage of lower than 1%. In order to meet the requirements, we used eight resonant full-bridge modules operated in parallel. Each resonant full-bridge module can supply the current of 0.9 A and the voltage of 40 kV, and is operated by N-phase shift switching pattern. In this paper, we present the design, simulation and test results of interleaved CCPS.

• Journal of Korean Critical Care Nursing
• /
• v.3 no.1
• /
• pp.41-51
• /
• 2010

Purpose: The purpose of this study was to identify the effects of family visits upon the stress response of patients and their families, Methods: This study was the interrupted time series design, The subjects consisted of 197 patients and 197 family members in the cardiac intensive care unit of S Hospital in Bucheon. Physiological stress responses such as blood pressure, heart rates, respiration rates, and oxygen saturation were measured using HP monitors. VAS was used to measure the emotional stress. Collected data was analyzed using repeated measure ANOVA, t-test by SPSS 17.0 statistical program. Results: The family visits did not change patients' blood pressure, pulse rate, respiration rate and oxygen saturation, However the anxiety level of patients and their family members were decreased significantly during family visits. Furthermore, 30-minute family visit reduced more effectively patient's anxiety than 15-minute family visit. Conclusion: Family visits need to be used as a means of nursing intervention to ease the emotional stress of patients and their families. In addition, increasing of visiting time should be considered.

• Korean Journal of Adult Nursing
• /
• v.15 no.1
• /
• pp.67-77
• /
• 2003

Purpose: This study was to examine the effects of music therapy on the levels of anxiety and discomfort in patients undergoing gastrofibroscopy. Method: This study was equivalent control group pre-post test design. The subjects were 61 patients who visited H hospital internal medicine department for gastrofibroscopy ; 31 were randomly selected for the control group and the remaining 30, for the experimental group. Result: 1. The experimental group who used music therapy showed a significantly lower level of anxiety during gastrofibroscopy than the control group. 2. The experimental group revealed a lesser change in pulse rate between pre and post gastrofibroscopy than the control group. 3. There was a significant difference in the levels of subjective and objective discomfort during gastrofibroscopy between the two groups. Conclusion: The results suggested that music therapy may help relieve anxiety and discomfort for patients undergoing gastrofibroscopy. These results showed that the use of music aided in the reduction of anxiety and discomfort during the unpleasant diagnostic procedure and, testing the effectiveness of music therapy deserves further study in other hospital settings.