• Journal of ILASS-Korea
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• v.14 no.3
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• pp.103-108
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• 2009

This research investigated spray characteristics using LPG fuel under compression ignition to contribute to develop a high efficiency LPG fuel is an environmentally-friendly fuel since it emits lower $CO_2$ compare to other conventional fuels. In order to observe spray process, a high speed digital camera and high pressure common-rail injector were applied. Using the spray behaviors of LPG and diesel fuel from the experiment, this research analyzed the mixing process of air-fuel mixture numerically with FLUENT 6.3 when LPG and diesel fuel injected directly into the cylinder while compression stroke occurs. Spray characteristics of LPG fuel was investigated by using numerical method, in which KH-RT model was adapted for phase change. As a result of numerical analysis, this work found out that LPG spray has a wider mixing formation and uniform diffusion of air-fuel mixture compare to diesel.

• Journal of the Korean Society for Precision Engineering
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• v.34 no.2
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• pp.83-87
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• 2017

A multi-step warm forging process for subminiature screws is investigated. Due to the low formability of Titanium alloys, bit forming of Titanium screws is difficult by cold forging. In order to overcome this low formability of Titanium alloys, two candidate processes, i.e., multi-step forging and warm forging are introduced. First, a multi-step (two-step) forging process is investigated. The punch shape and stroke of forging during the first step is designed via various analyses. Finally, the bit formability is investigated at different forging temperatures. Analyses are carried out for two-step forging at various temperatures and the formability under these thermal conditions is compared.

• The Journal of Korea Robotics Society
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• v.8 no.1
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• pp.8-19
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• 2013

One of the important issues for structural and electrical specifications in developing a robot is to determine lengths of links and motor specifications, which need to be appropriate to the purpose of robot. These issues become more critical for a gait rehabilitation robot, since a patient wears the robot. Prior to developing an entire gait rehabilitation robot, designing of a 1DOF assistive knee joint of the robot is considered in this paper. Human gait motions were used to determine an allowable range of knee joint that was rotated with a linear type actuator (ball-screw type) and links. The lengths of each link were determined by using an optimization process, minimizing the stroke of actuator and the total energy (kinetic and potential energy). Kinetic analysis was performed in order to determine maximum rotational speed and maximum torque of the motor for tracking gait trajectory properly. The prototype of 1 DOF assistive knee joint was built and examined with a impedance controller.

• The Journal of Korea Robotics Society
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• v.13 no.1
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• pp.63-71
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• 2018

This paper describes a study on posture control of the multi-legged biomimetic underwater robot (CALEB10). Because the underwater environment has a feature that all degrees of freedom are coupled to each other, we designed the posture control algorithm by separating each degree of freedom. Not only should the research on posture control of underwater robots be a precedent study for position control, but it is also necessary to compensate disturbance in each direction. In the research on the yaw directional posture control, we made the drag force generated by the stroke of the left leg and the right leg occur asymmetrically, in order that a rotational moment is generated along the yaw direction. In the composite swimming controller in which the controllers in each direction are combined, we designed the algorithm to determine the control weights in each direction according to the error angle along the yaw direction. The performance of the proposed posture control method is verified by a dynamical simulator and underwater experiments.

• Journal of Biosystems Engineering
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• v.22 no.2
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• pp.189-198
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• 1997

In order to find out the potential of LP gas as a substitute fuel for small fm engine, experiments were carried out with a four-stroke spark-ignition engine which was modified from a kerosene engine mounted on the power tiller. Performance characteristics of kerosene and LP gas engine such as torque, volumetric efficiency fuel consumption rate, brake thermal efficiency, exhaust temperature, and carbon monoxide and hydrocarbon emissions were measured and analyzed under various levels of engine speed and compression ratio. The results were summarized as follows. 1. It showed that forque of LPG engine was 41% lower than that of kerosene engine with the same compression ratio, but LPG engine with compression ratio of 8.5 it was showed similar torque level to kerosene engine with compression ratio of 4.5. 2. Fuel consumption of LPG engine was reduced by about 5.1% and thermal efficiency was improved by about 2% compared with kerosene engine with the same compression ratio. With the incrasing of compression ratio in LPG engine fuel consumption rate decreased and thermal efficiency increased. 3. Exhaust temperature of LPG engine was about 15% lower than that of kerosene engine. Concenrations of emissions from LPG engine was affected insignificantly by compression ratios, and carbon monoxide emissions from the LPG engine was not affected by engine speed so much. The carbon monoxide and hydrocarbon emissions from LPG engine were about 94% and 66% lower than those of kerosene engine, respectively.

• Proceedings of the Korean Society for Emotion and Sensibility Conference
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• 2008.10a
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• pp.46-49
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• 2008

This study aims to suggest basic materials to develop an emotional font for future Hangeul font development plan by investigating emotional reaction displayed through the subjects and by quantifying its contribution of the stimulation elements causing such reaction. For this, a survey of 150 university students who are currently enrolled in the College of Design was conducted in order to analyze correlation between 30 emotional words extracted from the Hangeul font and the selected 36 sample fonts. The combined data was described with the two dimensional dispersion using the quantification theory type III. The analysis found out that the Hangeul font forms the x-axis showing "soft(dynamic).hard(static)" and the y-axis showing "modern(light).classic(heavy)”. Specifically, there exist emotional groups such as "archaic","masculine","feminine","negative", and "modern static"on each axis. In addition, to extract the casual relationship between the value of emotional reaction and its stimulation elements quantitatively, the author indicated the emotional words of each axis and the total value of equivalent five emotional word groups as the standard variance and the constituent of Hangeul font as the independent variable, and then the quantification theory type I was used to analyze the physical elements of the Hangeul font. As a result, "the centerline of gravity(base line)" and "thickness variance of a stroke" on the two axes, and "the centerline of gravity(base line)" and "decoration" among the five groups were identified as the most influential elements that affect the emotional reaction of the subjects.

• Korean Journal of Acupuncture
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• v.20 no.3
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• pp.29-34
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• 2003

Objectives : The purpose of this study was to investigate the Effect of Acupuncture Chok-samni(ST36) on Skin temperature(ST), Galvanic skin response(GSR) and Heart rate(HR) in humans. ST36 is used in uneasiness, high fever, stroke, paralysis on oriental medicine. Methods : Subjects were 18 healthy oriental medical students volunteers(15male, 3female, mean age-28). Under sequence of ST36 acupuncture, the first group was observed ST, the second group was observed GSR and the third group was observed HR. Skin temperature was measured on Haegye acupoint(ST41) before and after acupuncture stimulation. Each test took 15minutes. This test was performed twice in order to increase the statistical authenticity. Results : Our result indicates that acupuncture stimulation of ST36 statistically decreased skin temperature on ST41. Also statistically decreased in HR. The change of GSR after ST36 acupuncture was decreased, but there is no statistical. Conclusions : These results suggested that acupuncture stimulation of ST 36 has effect on ST and HR in human body, and may be used by treatment as control the nerve system.

• Fire Science and Engineering
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• v.24 no.3
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• pp.9-19
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• 2010

Recently, Korea is constantly increasing its elderly care hospitals, and requires establishment of general evacuation plan considering old people's behavioral characteristics and physical states in emergency situations such as fire, and etc. In addition, because most of the facility users are patients under serious dementia and stroke, they feel difficulty evacuating by themselves, with differing evacuation time according to each walking status (bed, wheel chair, and various supplementary instruments), which is why it makes it difficult to have them all evacuate. This paper, in order to suggest data reference for designing on the basis of functionality, used various collected data utilizing Simulex to measure evacuation time through the model of elderly care hospital, a medical facility. During the study, several problems were found.

• Herbal Formula Science
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• v.18 no.2
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• pp.1-14
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• 2010

This report describes 57 prescriptions including Paeoniae Radix and Glycyrrhizae Radix in Dongeuibogam. Paeoniae Radix and Glycyrrhizae Radix have been used separately or concurrently in Oriental Medicine for a long time as a treatment for various disease. The following conclusions are reached through investigations on the applications of prescriptions including Paeoniae Radix and Glycyrrhizae Radix in Dongeuibogam. 1. 7 times(12.3%) prescriptions are recorded in women chapter, 6 times(10.5%) in cold chapter, 5 times(8.8%) in stool chapter and fatigue chapter each, 4 times(7.0%) in psychiatry chapter, which are arranged in order of frequency. 2. Anxiety, Yin-Yang deficiency, stroke, treating blood, cataract, fever floating due to Yin deficiency, weak and fatigue, pregnancy, abortion, women accessary disease, cold-feeling heart pain, stiffness, etc, among 51 symptoms in prescriptions including Paeoniae Radix and Glycyrrhizae Radix. 3. The dosage of Paeoniae Radix and Glycyrrhizae Radix are from 5 pun:2.5 pun to 2 nyang:1 nyang. 1 jeon:5 pun is recored 39 times(68.4%), 2 jeon:1 jeon and 1 nyang:5 jeon is 6 times(3.21%), 2 nyang:1 nyang is 2 times(1.8%) used among 57 prescriptions including Paeoniae Radix and Glycyrrhizae Radix. 4. 57 prescriptions including Paeoniae Radix and Glycyrrhizae Radix are mostly composed of Samooltang and Sagoonjatang, Gyejitang, Gamgiltang, Bowontang, Goongguitang, Jeongwoneum, Bojoongikgitang, Jigoongsan, Ijintang, Pyeongwuisan, Oryungsan, etc, according to the usage.

• Physical Therapy Korea
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• v.12 no.1
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• pp.71-79
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• 2005

The purpose of this study was to analyze the presence of ipsilesional movement deficit, with segmental performance in each proximal or distal upper extremity. The visuoperceptual complex task of the ipsilesional upper extremity was investigated in patients with unilateral brain damage and a control group of healthy sex-age-matched controls. Tracking movements were tested in the proximal and distal upper extremities. Movements were measured by the accuracy index, which was normalized to each subject's own range of motion and took into account any differences between subjects in the excursion of the tracking target. The findings revealed that stroke patients experienced difficulties with tracking movement of both proximal and distal segments in the upper extremities on the so-called "non-affected side", irrespectively of the extent of patient's age, time since onset, or severity of contralateral upper extremity. Therefore, the unilateral brain damage affected ipsilateral motor function of the proximal and distal upper limbs in the performance of complex motor tasks, requiring central processing and the higher order cognitive function in the integrity of both hemispheres.