• 대한산업공학회지
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• 제39권5호
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• pp.374-382
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• 2013

Robust design method developed by Genichi Taguchi has been very popular since the 1980s and there have been many academic and applied research works on this topic. However, college students and engineers in companies have had difficulty in understanding the method. This paper presents a procedure to implement the robust design method by an easy-to-execute paper helicopter experiment. A crossed array was adopted, which consists of a resolution IV fractional factorial design with 6 control factors and a factorial design with 3 noise factors. Three performance measures were analyzed; signal-to-noise ratio, mean, and standard deviation of the falling time of the paper helicopter that is to be maximized. Control-noise interaction plots are also given to evaluate the degree of the sensitivity of each level of the control factors to the noise factors. The procedure presented in this paper can be helpful to those who want to have basic knowledge in the robust design method.

• The Korean Journal of Physiology
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• 제9권1호
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• pp.77-82
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• 1975

This experiment was carried out to observe a biological effect of ginseng on the weight gain, physical performance and lactic acid production after exercise in mice. A group of mice weighing about 19 gm was divided into ginseng and cotrol group. on the treadmill (Exp. I & II) and LDH activity of liver and heart homogenates (Exp. II) were determined. Results are summerized as follows; 1. Body weight gain was greater id ginseng group than in control and the difference was statistically significant at 9th and 16th days of experimental period. 2. Maximal running time of ginseng was found to be longer than that of control (p<0.05) in experiment I and the experiment II also revealed the significant increase in maximal running time in ginseng group. 3. Bloo lactate concentration of 48 hour-rest from physical exertion was lower in ginseng group than in control (p<0.05). 4. LDH activity in liver homogenate was lower compared to control group, but in heart homogenate, it was greater in ginseng group. Above findings may be concluded tat the range of biological dose (20 mg/mice/day) of ginseng powder stimulated the body weight gain and increase of physical performance and its mechanism might be attributable to a lower level of blood lactic acid. The adaptive change of LDH activity also contributed to the change in lactate level in blood and tissue.

• 국제물리치료학회지
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• 제4권2호
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• pp.552-556
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• 2013

The purpose of this study is to examine the effects of feedback breathing exercise on respiratory muscle activity. Thirty stroke patients were randomly and equally assigned to an experimental group and a control group. The experimental group received rehabilitation exercise treatment for 30 minutes and feedback respiratory exercise for 30 minutes and the control group received rehabilitation exercise treatment for 30 minutes and conducted motomed exercise for 30 minutes. All of them conducted exercises five times per week for four weeks. Respiratory muscles including the upper trapezius(UT), longissimus dorsi(LD), rectus abdominis(RA), external abdominal oblique(EAO) and, internal abdominal oblique(IAO) were measured using MP 150WSW prior to and after the experiment. Regarding pulmonary functions prior to and after the experiment, the experimental group showed significant differences in all sections but the control group did not show significant differences in any sections. As for in-between group differences after the experiment, there were significant differences in the UT, LD, RA, and IAO but no significant differences in the EAO. In conclusion, respiratory muscle activity was more effective for the experimental group than the control group. It is considered that feedback respiratory exercise may induce improvement in respiratory muscles in stroke patients through feedback breathing exercise.

• International Journal of Fluid Machinery and Systems
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• 제7권1호
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• pp.1-6
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• 2014

The propellant acquisition vane (PAV) is a key part of a vane type surface tension propellant management device (PMD), which can manage the propellant effectively. In the present paper, the fluid transportation behaviors for five PAVs with different sections were investigated by using microgravity drop tower test. Further, numerical simulation for the propellant flow in a PMD under microgravity condition was also carried out based on VOF model, and showed the similar flow pattern for PAVs to the experiment. It is noted that the section geometry of PAVs is one of the main factors affecting the fluid transportation behavior of PMD. PAVs with bottom length ratio of 5/6 and 1/2 have larger propellant transportation velocity. Based on the experiments, there were two stages during the process of propellant transportation under microgravity environment: liquid relocation and steady transportation stage. It is also recognized that there is a linear correlation between liquid transportation velocity and relative time's square root. Those results can not only provide a guideline for optimization of new vane type PMDs, but also are helpful for fluid control applications in space environment.

• 대한기계학회논문집A
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• 제23권11호
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• pp.1912-1921
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• 1999

The equipments mounted on guided-missile undertake heavy vibrational disturbance. Sometimes the equipments mounted on guided-missile go wrong so that the guided-missile flies over unintended place. For the vibration isolation of the equipments mounted on guided-missile, active vibration control was performed. In the case of active vibration technique, the stiffness matrix and the mass matrix are derived based on FEM (ANSYS5.0). Model reduction was carried out and, as a result, we got 7 DOF mass and stiffness matrix. For the sake of FEM model identification, modal experiment was carried out. With the help of Sensitivity Analysis, the natural frequencies of FEM were tuned to those of Experiment. In this work, the Sky Hook and the LQG control theory were adopted for v iteration control using stacked piezoactuator. Experiments were performed with changing excitation frequency from 10 Hz upto 200 Hz and we got frequency response function of guided-missile equipments. The magnitude of 3rd mode of guided-missile equipments is 8.6 % that of Uncontrolled in Skyhook controller and is 3.4 % that of uncontrolled in LQG controller.

• 한국자동차공학회논문집
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• 제4권4호
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• pp.87-96
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• 1996

The proportional pressure control valve(PCV) is an essential component in the open loop controlled rear wheel steering gear of the four wheel steering(4WS) system on the passenger car. The valve should have versatile functions and higher performance. But, it is hard to find the proportional pressure control valve suitable for the 4WS system. In this paper, the determination of the valve parameters was studied by the stability discrimination and the characteristic analysis for the purpose of the development of a new PCV for the 4WS. The mathematical model of the valve was derived from the valve-cylinder system and the programme for numerical computation was developed. The transfer function of the system was obtained from the mathematical model. The characteristics of the valve were inspected through the experiment and compared to those obtained by numerical method. And then the stability discrimination of the system was done by root locus and the analysis of characteristics was done by the developed programme. From the experiment and the analysis of characteristics was done by the developed programme. From the experiment and the inspection, the appropriation of mathematical model and the usefulness of the programme were confirmed. And the parameters which might affect the performance of the valve can be determined by considering the stability discrimination, the characteristics analysis and required functions.

• Journal of Biosystems Engineering
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• 제26권4호
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• pp.371-378
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• 2001

This research devoted to develop an incubator that could make an optimum environment condition according to days of age for suckling pigs to decrease the mortality and improve the rate of the weight gain of the suckling pigs. Results obtained from this research summarized as follows: 1. Several experiments were carried out at the farm to find the effect of incubator developed for suckling pigs on weight gain by season. The total average gain of the weight of the treatment group was around 6∼22kg, and 6∼23kg higher than control group at the first experiment (April 19), at the second (July 30), and at the third (September 23), year of 2000 experiment, respectively. There were no significant differences ($\alpha$=5%) of the total weight gain among treatment groups. There was, however, a significant difference ($\alpha$=5%) of the total weight gain between the control and treatment groups and it was considered to be that the incubator had efficiency for weight gain of the suckling pigs. 2. The survival rate of the control group was 87% in the total sample number of 92, meanwhile, which of the experiment group was 98% in the total sample number of 50 suckling pigs. 3. Finally, economic analysis was executed for suckling pigs based on a farm size of breeding 500 sows. The results showed that a break-even point was around 9 months and the annual profit of ￦52,265,694 was expected after the break-even point.

• 한국산학기술학회논문지
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• 제7권6호
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• pp.1092-1099
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• 2006

본 논문에서는 유도전동기를 인버터와 같은 전력변환장치를 사용하여 정상상태의 동작특성은 물론 과도특성까지 해석하기 위해서는 유도전동기와 부하를 포함하는 전체 시스템의 정확한 동적 모델링을 이용하여 시스템 방정식으로 표현해야 한다. 또한 최대 견인력 제어를 위해서 속도센서리스벡터제어와 부하 토크 외란 관측기를 통하여 점착력 계수를 추정한다. 이와 같은 시스템의 제어 알고리즘을 구현하기 위하여 철도 모의 장치를 이용하여 제안된 알고리즘을 시뮬레이션과 실험을 통하여 확인하고, 철도 차량의 속도 가감에 따른 공전속도에 대한 점착력의 관계 등 제반 사항을 모의 장치에 의해서 구현하였다.

• 대한본초학회지
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• 제26권4호
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• pp.125-132
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• 2011

Objectives : An aim of study is to investigate effects of curculiginis rhizoma in vitro (factor Xa (FXa) inhibitor assay, prothrombinase assay, prothrombin time (PT) assay, activated partial thromboplastin time (aPTT) assay) and in vivo experiment (blood clotting time, thromboxane B2 content assay in serum and weight of thrombus by AV-shunt rat model). Methods : We gained a human serum and used serum in vitro study such as factor X activity (FXa) inhibition, prothrombinase inhibition, prothrombin time (PT) and activated partial thromboplastin time. Fifteen SD rats were divided into three groups (intact control group and two experimental group treated with extract of Curculiginis Rhizoma(ECR)). Rats were orally administrated DW (intact control group), 600 mg/kg concertration of ECR and 200 mg/kg concertration of ECR. After one hour, we anesthetized rats and made arteriovenous (AV) shunt rat models to study weights of thrombus, took a hole blood to study content of thromboxane B2 and blood clotting time. Results : In vitro, ECR increased a inhibitory activity of FXa, prothrombinase and aPTT compared than intact control group. Especially ECR made significant increase of FXa and prothrombinase inhibitory activity (p<0.05, p<0.01). And PT were increased in ECR control group compared with intact control group. In vivo, a blood clotting time of experiment group treated with ECR 600 mg/kg were significantly increased compared with that of intact control group (p<0.05) and content of thromboxane B2 was significantly decreased in group treated with ECR 600 mg/kg in seum. The weight of thrombus were significantly reduced in group treated with ECR 600 mg/kg compared with intact control group (p<0.05). But in vivo experiment study, those of group treated with ECR 200 mg/kg were reduced compared with those of intact control group without statistical significance. Conclusions : ECR has a antithromboic activity in internal course with inhibitory activity of FXa and prothrombinase in vitro, it required to research more study for effective compounds.

• 대한한의학회지
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• 제19권1호
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• pp.5-18
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• 1998

The purpose of this study was to determine the effects of aqua-acupuncture of Laennec N HO (Hominis placenta Cervi pontotrichum cornu Carthami semen). on trabecular area and physiological change in ovariectomized osteoporotic rats. This experiment was performed to .investigate an antiosteoporosis. effects of Laennec N HO(Hominis placenta Cervi pontotrichum cornu Carthmi semen) aqua-acupuncture on the osteoporosis induced by both ovariectomy in Rats. So rats were divided into Sham group and OVX group. OVX groups were divided into control group, Exp. I group, Exp II group and Exp III group). The Ratios of trabecular area seen in ephiphysis and diaphysis of tibia and lumbar vertebral body and physiological change were as follows. 1. In the proximal ephiphysis of tibia, Exp I II III groups were significantly increased compared to that in control group (p<0.05). 2. In the diaphysis of tibia, Exp III group were significantly increased compared to that in control group (p<0.05). 3. In the first lumbar vertebral body, Exp II group were significantly increased compared to that in control group. 4. In the cortical thickness index of tibia, Exp III III groups were significantly increased compared to that in control group. 5. Osteoca1cin was increased in the Exp II group than those of other Experiment groups and control group, and Phosphorus was decreased in the Exp I II group than that in control group, But a significant difference was not seen. GOT, GPT and Alkaline phosphatase were decreased in all Experiment groups than that in control group. But a significant difference was not seen. From the above results, it might be suggested that aqua-acupuncture Laennec N HO(Hominis placenta Cervi pontotrichum cornu Carthami semen) prevented the increase in bone turnover and the decrese in bone mass induced by OVX in rats.