• Journal of the Korea Convergence Society
• /
• v.10 no.6
• /
• pp.95-101
• /
• 2019

The purpose of this study was to determine whether PNF respiratory convergence exercise increases the pulmonary function of normal adults by $45^{\circ}$ leaning sitting position. Twenty normal adults in their 20s were randomly assigned to an experimental group (n=10) or control group (n=10). Over the course of four weeks, the experimental group participated in PNF respiration exercises by $45^{\circ}$ leaning position for 30 minutes three per week. And the control group participated in PNF respiration exercises by supine position for 30 minutes three times per week. Subjects were assessed pre-test and post-test by measurement of pulmonary function. Our findings show that the experimental group had significant improvements in expiratoy reserve volume and vital capacity, maximal voluntary volume. In this study, the experimental group showed greater improvement in pulmonary function than the control group, which indicates that the PNF respiratory exercise by $45^{\circ}$ leaning sitting position is effective at increasing the pulmonary function of normal adults.

• Journal of Bio-Environment Control
• /
• v.10 no.1
• /
• pp.42-49
• /
• 2001

This study was carried out to develop a fuzzy control technique of ventilation window for controlling a temperature in a greenhouse. To reduce the fuzzy variables, the inside air temperature shop was taken as one of fuzzy variables, because the inside air temperature variation of a greenhouse by ventilation at the same window aperture is affected by difference between inside and outside air temperature, outside wind speed and the wind direction. Therefore, the antecedent variables for fuzzy algorithm were used the control error and its slop, which was same value as the inside air temperature slop during the control period, and the conclusion variable was used the window aperture opening rate. Through the basic and applicative control experiment with the control period of 3 minutes the optimum ranges of fuzzy variables were decided. The control error and its slop were taken as 3 and 1.5 times compared with target error in steady state, and the window opening rate were taken as 30% of full size of the window aperture. To evaluate the developed fuzzy algorithm in which the optimized 19 rules of fuzzy production were used, the performances of fuzzy control and PID control were compared. The temperature control errors by the fuzzy control and PID control were lower than 1.3$^{\circ}C$ and 2.2$^{\circ}C$ respectively. The accumulated operating size of the window, the number of operating and the number of inverse operating for the fuzzy control were 0.4 times, 0.5 times and 0.3 times of those compared with the PID control. Therefore, the fuzzy control can operating the window more smooth and reduce the operating energy by 1/2 times of PID control.

• Journal of agriculture & life science
• /
• v.44 no.4
• /
• pp.69-77
• /
• 2010

Fuzzy control is widely used for improving temperature control performance as controlling ventilation in greenhouse because the technique can respond more flexibly to the outside air temperature and wind speed. By pre-studied PID and normal fuzzy control this study was performed to obtain the fundamental data that can be established in better greenhouse ventilation control method. The temperature control error by the simple fuzzy control was $1.2^{\circ}C$. The accumulated operating size of the window and the number of operating were 84% and 13, respectively. These showed equivalent control performance with pre-studied result that control error. The accumulated operating size of the window and the number of operating were 75% and 12, respectively. The proposed fuzzy technique was simple control logic method compared with step and PID control methods, but it showed equivalent performance. Therefore, the proposed simple fuzzy control method could be used in micro controller of small programmable memory size and many applications.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.19 no.2
• /
• pp.15-20
• /
• 2018

The objective of this study is to numerically investigate the thermal characteristics of an automobile exhaust-based heat exchanger for automotive thermoelectric power generation with various exhaust gas mass flow rates and temperatures. The heat exchanger for automotive thermoelectric power generation has a square-type pin installed inside, so the maximum amount of heat can be transferred to the thermoelectric element from the heat energy coming from the automobile exhaust gas. The exhaust gas mass flow rate changed from 0.01, to 0.02, to 0.03 kg/s, and the exhaust gas temperature changed from 400, to 450, to 500, to 550, to $600^{\circ}C$, respectively. A numerical simulation was conducted by using the commercial program ANSYS CFX v17.0. Consequently, the exhaust gas pressure difference between the inlet and the outlet of the heat exchanger is determined according to the flow rate of the exhaust gas. When the mass flow rate of the exhaust gas increased, the pressure difference between the inlet and the outlet of the heat exchanger increased, but the exhaust gas pressure difference between the inlet of the heat exchanger and the outlet did not vary with the exhaust gas temperature. Therefore, in order to obtain the maximum surface temperature from the heat exchanger, the exhaust gas mass flow rate should be lower, and the exhaust gas temperature should be higher.

• 전기의세계
• /
• v.28 no.2
• /
• pp.14-22
• /
• 1979

전력계통의 증대에 따라 변전소용 변압기도 대용량화되어 가고 있다. 변전소용 대용량 변압기의 경우 최대문제가 되는 것은 철도운송의 경우 운송한계에 있다. 일본의 철도는 협궤이기 때문에 운송능력이 작고 275KV 변압기의 경우 조립운송할 수 있는 한계용량은 종래 300MVA라고 되어 왔지만, 최근 기술의 진보와 신뢰성 향상 시책에 따라 450MVA까지도 철도운송을 하는 것이 가능케 되었다. 이와같은 사정때문에 당사는 이번에 중부 전력.북풍전변전소에 3상 60Hz, 275/15 4/31.5KV, 450/450/135MVA 변압기를 납품하였다. 본기는 초고압 변전소용으로는 일본에서 최대급의 것으로 여러가지의 특징을 가지고 있다. 그 주요점을 들면, (1) 철도에 의한 조립운송을 가능케 했다. 더우기 부하시 TAP 절환기를 본체 TANK에 조립해서 운통한다. (2) 일차 초고압 권선에는 선로단을 중앙에 배치한 HISERCAP 권선을 채용한다. (3) 당초 65Phon, 장래 55Phon의 저소음사양을 만족시키기 위해서 고효율의 송유풍냉식 저소음방열관을 사용했다. (4) 기기의 신뢰성을 높이기 위해 설계, 제조, 시험 검사 각면에 만전을 기했다. 그러나 그외에도 여러가지 연구가 추진되고 있으며 다음에 개요를 설명하고져 한다.

• Tunnel and Underground Space
• /
• v.11 no.4
• /
• pp.319-327
• /
• 2001

Introduction of new design tools has been required to optimally design and operate the ventilation system of long vehicle tunnels.. The demand has led to wide spread use of the simulation technique throughout the would to analysis the dynamic relationship among the variables associated with vehicle tunnel ventilation. This paper aims at performing on-site study at local tunnels to test the applicability of NETVEN, a simulation model vehicle tunnel ventilation. The study was carried out at four urban as well as highway tunnels model of vehicle tunnel ventilation. The study was carried out at four urban as well as highway tunnels employing different ventilation systems as well as traffic methods. There were some discrepancies sound between the simulation output and measurements and the following four factors are considered to mainly cause those disagreement. (1) The real situation shows distinctive transient and retarding characteristics with respect to air flow and contaminant dispersion, while ventilation forces are not steady-state and in particular those traffic and climatic variables show significant instantaneous variation. (3) Near the exit portal, the CO levels show bigger differences. The general trend is that data with higher CO concentrations carry bigger discrepancies. Turbulent diffusion is though to be the main reason for it and also contribute to the fact hat the highest CO concentrations are found at the locations somewhat inward, not at the exit portals. (4) Higher traffic rate results in higher discrepancies of ventilation velocity. Along with the exhaust characteristics, the vehicle aerodynamic characteristics need to be studied continuously in order to reduce the velocity disagreement.

• Journal of the Korea Convergence Society
• /
• v.11 no.10
• /
• pp.125-131
• /
• 2020

This study sought to reduce the risk of fractures in elite youth taekwondo athletes to find out the relationship between bone mineral density which are used as indicators of early diagnosis of osteoporosis and cardiorespiratory functional capacity which is an indicator of performance and sports injury the harmful to athletes. The Pearson product-moment correlation was performed to investigate the correlation between bone mineral density, cardiorespiratory functional capacity, and sports injury. The bone mineral density and cardiorespiratory functional capacity, sports injury were examined the relationship using the Simple Linear Regression. The bone mineral density were correlated with the ventilation (r=.388), and VO2max (r=.478). Bone mineral density was correlated with sports injury (r=-.292). When the bone mineral density increased by .002 and .006, the ventilation (p=.001) and VO2max (p=.006) increased by about 1. In addition, when the bone mineral density decline by .016, the sports injury increased by about 1. Improving athletes' bone mineral density can prevent sports injury, and it can be used as a sports injury prevention program in the future.

• Tuberculosis and Respiratory Diseases
• /
• v.40 no.5
• /
• pp.548-557
• /
• 1993

Background: Bronchiectasis is a irreversible disease, a lot of cases of which are associated with chronic bronchitis, pulmonary emphysema and bronchial asthma due to chronic recurrent pulmonary infection. Therefore, pulmonary functions in bronchiectasis may also vary with associated diseases or involved segments. Methods: For the evaluation of ventilatory dynamics in bronchiectasis with respect to the pathoanatomic types of bronchiectasis and the degree of dyspnea, a total of 93 cases comprising 45 cases of tubular, 30 saccular and 18 mixed type of bronchiectasis whose clinical diagnosis was confirmed by bronchography were analyzed retrospectively. They were also divided into two groups: those with Hugh-Jones dyspnea grade 1 & 2 (group I) and those with Hugh-Jones dyspnea grade 3 & 4 (group II). Pulmonary functions tested in this study were analyses of curves of forced expiratory volume and flow-volume, and determinations of maximal voluntary ventilation and closing volumes. Results: The results were as follows; 1) The vital capacity and parameters reflecting expiratory flow rate except PEF were significantly reduced in saccular and mixed type than that in tubular type of bronchiectasis. 2) In saccular and mixed type, the maximal voluntary ventilation tended to decrease while CV/VC tended to increase. 3) As the degree of dyspnea became serious, the involved segments were progressively increased. In contrast, ventilatory functions were significantly reduced in proportion to the severity of dyspnea. Conclusion: These findings suggest that in bronchiectasis, there be obstructive ventilatory impairment combined with mild restrictive ventilatory impairment, which becomes more prominent in saccular and mixed type and also as the degree of dyspnea progresses.

• Journal of the Institute of Convergence Signal Processing
• /
• v.7 no.3
• /
• pp.130-135
• /
• 2006

There have been experiments dealing with the possibility of the actualization of the ANC system by means of operating the DSP adaptation filter. This filter is composed of various filters(including X-LMS algorithm, Filter-U algorithm, and Full-Feedback-Filter-U algorithm) that use ventilation fans and loudspeakers as a primary source in a circular duct as an experimental device. In this operation, the ANC system using the X - LMS algorithm was found to be more effective in reducing noise than without such system. When applying the input signal of the DSP board Full Feedback-Filtered-U algorithm system while having in mind that the additionally installed second control signal was gone through feedback and mixed into the detection microphone installed near the ventilation fan when using the first ventilation fan, the system was not emitted, but maintained stable during the operation of the control filter. At this point, noise tended to decrease at a maximum of l0dB compared to other algorithms at the frequency band of 170-250Hz.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.22 no.2
• /
• pp.330-337
• /
• 2018

This paper proposes a technique to analyze the flatness characteristics of the attenuator at 10Hz to $50\text\tiny{MHz}$ on the basis of $1\text\tiny{kHz}$ using a Thermal Voltage Converter and AC measurement standard. In the proposed technique, the input voltage of the attenuator for each measuring frequency is supplied at the same rate as $1\text\tiny{kHz}$ using TVC, and the flatness characteristics of the attenuator are analyzed by the voltage variation indicated in the AC measurement standard. The results of the analysis of the attenuator flatness characteristics show that the maximum uncertainty of $866{\mu}V/V$ can be measured from $10\text\tiny{dB}$ to $70\text\tiny{dB}$ and the uncertainty is reduced by about 37% compared to $2.31\text\tiny{mV}$/V using the network measurement method. The improved attenuator flatness characteristic values can be applied to the frequency flatness calibration from 2.2V to 2.2mV at the low voltage of the AC measurement standard.