• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2011년도 춘계학술대회 초록집
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• pp.202-202
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• 2011

Performance of the raw water-source heat pump system with a thermal storage tank has been analyzed in winter season. The raw water is transferred through the multi-regional water supply system from Han river. Raw water is large temperature difference resource compared with groundwater. Although the raw water temperature drops to $0.6^{\circ}C$ due to the heavy snowfall and the severe cold in late January and early February, 2010, the system has been normally operated without any trouble this winter. The unit COP and system COP considered all pump power consumption were estimated based on the second-by-second data of the all sensors. The monthly averaged unit COP and system COP are 3.37 and 2.76 respectively with $1.4^{\circ}C$ of raw water in January, 3.55 and 2.89 with $1.6^{\circ}C$ raw water in February, 3.82 and 3.15 with $5.4^{\circ}C$ raw water in March. The performance of the system are increased with raw water temperature, and the COPs are higher than the water-to-air heat pump system using relatively high temperature raw water from Daecheong reservoir because the water-to-water system was operated on the full load condition and was stopped when the thermal storage tank was full of the high temperature water.

• 한국전문물리치료학회지
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• 제23권3호
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• pp.40-47
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• 2016

Background: Assessments of Sit-to-Stand (STS) and gait functions are essential procedures in evaluating level of independence for the patients after stroke. In a previous study, we developed the software to analyze center of pressure (COP) in standing position on Wii Balance Board (WBB). Objects: This purpose of this study is to measure test-retest reliability of ground reaction forces, COP and time using WBB on STS and gait in healthy adults. Methods: Fifteen healthy participants performed three trials of STS and gait on WBB. The time (s), vertical peak (%) and COP path-length (cm) were measured on both tasks. Additionally, counter (%), different peak (%), symmetry ratio, COP x-range and COP y-range were analyzed on STS, 1st peak (%), 2nd peak (%) of weight were analyzed on gait. Intra-class correlation coefficient (ICC), standard error measurement (SEM) and smallest real difference (SRD) were analyzed for test-retest reliability. Results: ICC of all variables except COP path-length appeared to .676~.946 on STS, and to .723~.901 on gait. SEM and SRD of all variables excepting COP path-length appeared .227~8.886, .033~24.575 on STS. SEM and SRD excepting COP path-length appeared about .019~3.933, .054~11.879 on gait. Conclusion: WBB is not only cheaper than force plate, but also easier to use clinically. WBB is considered as an adequate equipment for measuring changes of weight bearing during balance, STS and gait test which are normally used for functional assessment in patients with neurological problems and elderly. The further study is needed concurrent validity on neurological patients, elderly patients using force plate and WBB.

• The Journal of Korean Physical Therapy
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• 제21권3호
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• pp.75-80
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• 2009

Purpose: The purpose of this study was to examine the effect of an obstacle height on the balance control of older adults while stepping over an obstacle from a position of quiet stance. Methods: Fifteen community-dwelling healthy older adults (mean age, $74.4\pm4.27$ yrs; age range, 67-82 yrs) volunteered to participate in this study. The subjects performed gait initiation (GI) and they stepped over obstacles of two different heights (10 cm and 18 cm) at a self-paced speed from a position of quiet stance. Their performance was assessed by recording the changes in the displacement of the COP in the anteroposterior (A-P) and mediolateral (M-L) directions using a force platform. Results: The M-L displacement of the COP significantly increased for an 18 cm obstacle height condition as compared to the GI and a 10 cm obstacle height condition (p<0.01). Furthermore, the M-L displacement of the COP for a 10 cm high obstacle was significantly greater for that for the GI (p<0.01). However, the mean of the A-P displacement of the COP was similar between the stepping conditions for the A-P displacement of the COP (p>0.05). Conclusion: This study suggests that the M-L COP displacement could be a better parameter to identify the dynamic balance control in older adults when negotiating obstacles.

• 대한설비공학회지:설비저널
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• 제14권3호
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• pp.200-211
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• 1985

The paper discusses the problem of the reduction in Coefficient of Performance (COP) in a refrigerator due to the inadequate position or some flow obstacles such as shelves in a room. The propriety of the present numerical method has teen proved by experiments using the flow visualization technique. The COP are calculated from the temperature rise of the condenser whose temperature indicates the condensing temperature of refrigerant The temperature rise is predicted by the theory of the steady two-dimensional laminar natural convection. In a room size of $2m\;{\times}\;2m$ the COP are decreased by 0.3 when the gap between the wall and condenser are decreased from 10cm to 2cm. While the COP are decreased by 0.55 as the shelf length increases from 0 to 75cm.

• Physical Therapy Rehabilitation Science
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• 제10권3호
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• pp.270-277
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• 2021

Objective: The purpose of this study is to compare the effect of static balance, lower extremity function, and gait ability between a lower extremity restrain robot gait training and a general robot gait training in subacute stroke subjects. Design: Two-group pretest-posttest design. Methods: A total of 12 subacute stroke patients were randomly divided into an Experimental group (n=6) and a control group (n=6). Both groups were performed for four weeks, three times a week, for 20 minutes. To compare the Static balance function, the center of pressure (COP) path-length and COP velocity were measured. The Fugl-Meyer assessment lower extremity (FMA-LE) were evaluated to compare the Lower Extremity function. 2D Dartfish Program and 10 Meter Walking Test (10 MWT) on Gait ability were evaluated to compare the gait function. Results: In the intra-group comparison, Experimental groups showed significant improvement in COP path-length, velocity, Lower Extremity Function, 10 MWT, Cadence, by comparing the parameters before and after the intervention (p<0.05). Comparison of the amount of change between groups revealed significant improvement for parameters in the COP path-length, velocity, Lower extremity function, 10 MWT by comparing the parameters before and after the intervention (p<0.01). Conclusions: The Experimental group showed enhanced efficacy for variables such as COP path-length, velocity, Lower extremity function, 10 MWT as compared to the control group.

• 한국기계기술학회지
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• 제13권3호
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• pp.93-98
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• 2011

To analyze and evaluate the performance of developing air to water multi heat pump, the heat pump was installed and tested at low energy house in Daejeon, korea. Heating capacity of heat pump is 16.5KW and cooling capacity is 14.0KW. Space heating/cooling, floor heating and hot water is available. The results performance evaluation of heat pump in lab test showed that the coefficient of performance (cop) was 3.75, and heating capacity was 16.0KW in ambient temperature $7^{\circ}C$. Also at ambient temperature $-15^{\circ}C$, the COP was 1.69. At a low energy house, floor heating is controled by a floor heating water temperature and a room temperature. The COP of heat pump is decreased with frequent on/off operation for controlling of floor heating water temperature.

• Journal of Biosystems Engineering
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• 제27권3호
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• pp.235-240
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• 2002

Performance of the heat pump with attaching an air heat exchanger was investigated in the heating condition when the air heat exchanger was worked in the ambient air temperature of -5 to 11$\^{C}$ and air flow rate of 542 to 747 ㎡/h. Performance tests for heating condition were conducted in an experimental room equipped with heat pump. The performance tests were performed in a ambient temperature of -4 ∼ 11$\^{C}$, and room temperature of 4∼22$\^{C}$ respectively. Measured data(temperature, capacity of heat transfer and consumption of electronic power) were analyzed to the efficiency of HEEVA(Heat Exchanger fur the Evaporator), overall heat transfer coefficient and COP of heat pump. The results of inlet temperature for evaporator increased that the temperature was 2 ∼6$\^{C}$, and inlet temperature for condenser decreased that the temperature was 3 ∼ 8$\^{C}$. The results of comparing efficiency of HEEVA for the ratio of heat exchange between hot air and cold air showed that efficiency were considered to 91% because of the ratio of 83∼98%. The results of comparing of COP for the heat pump increased that improvement COP was approximately 0.3∼7.5 than HEEVA had not been operated.

• 설비공학논문집
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• 제25권3호
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• pp.156-163
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• 2013

Ground Source Heat Pump (GSHP) systems utilize geothermal energy as a thermal source or sink, for heating, cooling and domestic hot water. It is well known that GSHP is environmentally friendly, and saves energy dramatically. For this reason, many investigative researches have been conducted on commercial and governmental buildings. However, studies on residential GSHP are few, because of the small capacity and cost. In this study, we experimented with the characteristic performance of heating, cooling and seasonal performance factor for a residential GSHP system, which consisted of two 180 m deep u-tube ground heat exchangers, a heat pump and measurement instruments. The installed capacity of the heat pump was 5RT, and the conditioning area was $62.23m^2$. From the experimental results, the cooling COP of the heat pump was 4.13, and the system COP was 3.51, while the CSPF was 3.32. On the other hand, the heating COP of the heat pump was 3.87, and the system COP was 3.39, while the HSPF was 3.39. Also, in-situ cooling COP and capacity were 93.7% and 96.4% compared with the EWT certification data, respectively, and that of heating were 98.3% and 95.7%, respectively.

• 국제물리치료학회지
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• 제10권3호
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• pp.1823-1829
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• 2019

Background: Stroke patients have leg muscle weakness and impaired balance resulting in compensatory changes. To restore balance in these patients, functional training using postural strategy is needed. Objective: To examine the effects of ankle and hip strategy training on the center of pressure (COP) movement and limits of stability (LOS) in standing posture in stroke patients. Design: The study was an assessor-blinded and randomized-controlled clinical trial. Methods: Thirty patients were randomly assigned to an ankle strategy training group and a ankle/ hip strategy training group. Patients in the ankle strategy training group underwent ankle strategy exercise for 30 min, and those in the ankle/ hip strategy training group underwent 15 min of ankle strategy exercise and 15 min of hip strategy exercise. Both groups underwent training thrice a week for four weeks. Forward, backward, paretic side, and non-paretic side COP movements and LOS were measured using BioRescue. Results: After the intervention, except for the backward area in the ankle strategy training group, the COP movement area and the LOS were significantly improved in both the groups. In addition, these improvements were significantly higher in ankle/ hip strategy training group than that in the ankle strategy training group. Conclusions: Ankle strategy training in addition to hip strategy training improves COP movement (forward-backward, paretic side area, and non-paretic side area) and LOS in stroke patients.

• 한국응용과학기술학회지
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• 제37권2호
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• pp.224-231
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• 2020

본 연구의 목적은 유도 허벅다리걸기 기술 발휘 시 발목 관절의 테이핑 처치가 하지 관절과 압력중심(COP, center of pressure)에 미치는 영향을 분석하는데 있었다. 대학 유도 선수 20명(연령, 20.9±0.8세; 신장, 168.6±7.4cm; 체중, 73.5±11.6kg; 신체질량지수, 25.7±2.6kg/㎡)이 참여하였으며, 발목 관절 테이핑 처치 전과 후의 2가지 조건에서 허벅다리걸기 기술 발휘 시 지지다리 관절의 각도와 압력중심 요인을 분석하여 다음의 결과를 도출하였다. E2(t=2.411, p=.027) E4(t=2.388, p=.029)시점에서 발목 관절의 각도는 테이핑 처지 전에 비해 처치 후 발목의 각도가 통계적으로 적은 수치를 나타내었고, E2(t=-2.343, p=.032) E3(t=-4.531, p=.000)시점에서 힙 관절의 각도는 통계적으로 크게 나타났다. 그리고 발목 관절 테이핑 처치 후 좌·우의 COP 이동은 상대를 메치는 P3 국면에서 통계적으로 크게 나타났으며(t=2.670, p=.016), 전·후의 COP 이동은 상대의 무게 중심을 기울이는 P1 국면에서 통계적으로 적은 수치를 나타내었다(t=2.846, p=.011). 그러므로 허벅다리걸기를 특기로 사용하는 유도 선수들은 발목 관절 테이핑으로 인해 발생하는 지지관절의 운동 기능과 COP의 이동범위를 고려하여 사용하는 것에 대하여 제안하고자 한다.