본 연구의 목적은 고정저항과 가변저항을 적용한 백 스쿼트 시 단축성 구간을 전반부와 후반부 로 나누어 신체중심의 속도와 근전도 분석을 통하여 스티킹 포인트에 미치는 영향을 분석하는 것이다. 본 연구의 대상자로 19세 이상의 성인 15명이 연구에 참여하였다(연령: .25.8±2.6 yr, 신장: 181.4±2.2 cm, 체중: 79.7±3.9 kg). 2가지 부하 방법(고정부하, 고정부하+가변부하)를 통하여 백 스쿼트 시 3차원 동작분 석과 하지 근전도를 통하여 자료를 수집하였다. 이에 따른 결론은 다음과 같다. 신체중심의 속도는 VRT가 CRT보다 빠른 속도가 나타났고, 후반부가 전반부보다 빠른 속도가 나타났다. 근전도 분석에서 대퇴직근은 CRT가 VRT보다 근활성도가 크게 나타났고, 전경골근은 CRT의 전반부가 후반부보다 근활성도가 크게 나타났지만, VRT는 차이가 없었다. 이러한 결과를 통하여 고정부하의 약점을 가변부하를 통하여 효율적인 운동을 기대할 수 있다.

상수도 배관에서 누수 또는 이상을 감지하는 기계학습 및 인공신경망 분류 모델에 대한 연구가 활발히 진행되어 왔다. 그러나 누수음 데이터는 시간과 환경에 따라 계속 변동하기 때문에, 입력 데이터의 변화에도 일정 수준 이상의 분류 성능을 유지하는 분류 모델을 찾는 데 어려움이 있다. 본 연구에서는 모델 선택과 초매개변수 조정보다 데이터 전처리 방법이 분류 성능 향상에 더 큰 영향을 미친다는 점에 주목했다. 변동성이 큰 누수음의 특징을 효과적으로 추출하기 위해 푸리에 변환 및 MFCC(Mel-Frequency Cepstral Coefficients)를 사용하였으며, 일부 정보가 중복될 가능성을 고려하여 다중공선성에 덜 민감한 트리 기반 모델을 사용해 누수음의 분류 성능을 평가했다. 연구 결과, 푸리에 변환과 MFCC를 결합한 데이터 세트를 사용했을 때 LightGBM 모델의 분류 정확도가 84.62%로 나타났으며, 각각의 전처리 방법을 단독으로 사용했을 때보다 더 높은 성능을 달성하였다. 이 결과는 두 전처리 방법의 상호 보완적 특성이 분류 성능 향상에 기여했음을 입증하며, 상수도 관망 누수 탐지 시스템 개발에 중요한 기여를 할 것으로 기대된다.

In this study, the calorimeter was used to experimentally investigate the heating characteristics of the variable A/C system according to changes in loading time and outdoor dry bulb temperature. The heating capacity, COP and compressor discharge temperature were measured while changing the loading time of the compressor. To develop the correlation for compressor discharge temperature, loading time, indoor dry bulb temperature and outdoor dry bulb temperatures were considered as operating variables. As the outdoor temperature and loading time increased, the heating capacity and COP increased. However, the change in COP showed different trends depending on the outdoor temperature. The evaporation temperature according to the loading time is a good estimate of the outdoor temperature. However, as the temperature difference between indoor and outdoor rooms decreases and the loading time increases, the condensation pressure increases significantly, so the condensation temperature increases. The maximum deviation between the correlation and the experimental value for compressor discharge temperature was within approximately 2℃.

Noise is defined as ‘unwanted sound’ or ‘undesired sound’. Recently, the aviation industry has been rapidly developing through convergence with cutting-edge technologies such as UAM. Accordingly, it is expected that new aviation industry models will continue to be created in Korea. In addition, it is expected that aircraft noise will be raised as a new social problem. The characteristic of aircraft noise is that it has a wide transmission range. Therefore, the area affected by aircraft noise is extensive, and the damage area varies depending on the flight path and flight environment. Additionally, it tends to occur continuously in certain areas. This study is an extension of the previous studies 􋺷Study on noise measurement and analysis of C172 aircraft at Muan Airport􋺸 and 􋺷Study on noise measurement and analysis of SR20􋺸, and investigated the noise characteristics of various piston engine trainer aircraft operated in Korea. We want to measure and analyze noise.

In this study, the calorimeter was used to experimentally investigate the cooling characteristics of the variable A/C system according to changes in loading time and outdoor dry bulb temperature. The cooling capacity, COP and compressor discharge temperature were measured while changing the loading time of the compressor. To develop the correlation for compressor discharge temperature, loading time, indoor and outdoor dry bulb temperatures, evaporation and condensation temperatures were considered as operating variables. As the loading time increased, the cooling capacity and COP increased. The cooling capacity increased linearly with the loading time. The COP increased more at low loading times than at high loading times. The change in condensing temperature according to the loading time had a small temperature fluctuation range, and the evaporation temperature decreased linearly. The compressor discharge temperature increased linearly with the loading time and outdoor temperature, and the maximum deviation between the experimental value and the correlation was within about 2℃.

Bovine rotavirus (BRV) is one of the common gastrointestinal diseases that can occur in calves, causing severe diarrhea. This study was conducted to investigate the effects of oral administration of single-domain antibodies, single variable domain of heavy chain of HCAb (VHH), on the prevention and treatment of rotavirus-induced diarrhea in calves. Thirty calves were divided into five experimental groups (negative control, positive control, group A, group B and group C). Except for the negative control group, the experimental groups were inoculated with BRV on the 4th day after birth. The VHH supplementation groups were fed with a substitute milk containing different concentrations of VHH (1%, 2.5% and 7.5%). Changes in body weight, clinical symptoms, serum antibodies, and virus detection in feces were observed for a total of 10 days in each experimental group. The results showed a higher survival rate in the VHH supplementation groups compared to the positive control group. Clinical symptoms caused by rotavirus were alleviated in the VHH supplementation groups. The detection rate of rotavirus in feces also decreased. Gross findings indicated that the severity of disease in the VHH supplementation groups was milder than that in the positive control group. Therefore, VHH could be proposed as a useful alternative for the prevention and treatment of rotavirus-induced diarrhea in calves.

게임 엔진과 같은 3D공간에서 프로시저럴 모델링 애셋을 사용하여 도시를 구성하는 방식은 이전부터 존재하여 다양한 방법으로 제작되어 왔습니다. 초기 제작시간은 길지만 라이브러리가 구축됨에 따라, 크기와 모양이 다양한 건물을 보다 빠르고 다양하게 배치가 가능하다는 장점 을 바탕으로 사용되었습니다. 하지만, 앙곡과 안허리곡으로 이루어진 이중곡선을 가지며 결구 방식에 따라 모양이 변화하는 한옥의 경우에는 프로시저럴 기법으로 모델링 애셋을 제작하기 어려워 수동 모델링이나 스캔 데이터 형식으로만 존재하는 불편함이 존재하였습니다. 그렇기 에, 본 연구에서는 게임 엔진에서 사용이 가능한 가변적인 한옥 모델링에 대한 프로시저럴 기 법에 대해 소개하고자 합니다.

In the present study, a calorimeter was used to experimentally investigate the heating capacity and COP changes according to the pipe length of a variable capacity A/C system with long pipes. Cooling capacity, COP, and compressor discharge temperature were obtained by changing pipe lengths and loading duties at fixed indoor and outdoor temperatures. And the operation status and cycle change process of the A/C system were investigated using some experimental data and P-h diagrams. As the pipe length changes, the heat transfer within the cycle and the operating load of the compressor change, so the heating capacity and COP of the system change. At the same loading duty, as the pipe length increases, the heating capacity and COP decrease. As the loading duty increased, the heating capacity increased almost linearly, but the COP decreased. Since the long pipe experimental value for the compressor discharge temperature has a temperature deviation of up to 1 7℃(50m, L/D : 10/10) from the correlation equation, the optimal correlation equation must be derived through additional research.

In the present study, a calorimeter was used to experimentally investigate the cooling capacity and COP changes according to the pipe length of a variable capacity A/C system with long pipes. Cooling capacity, COP, and compressor discharge temperature were obtained by changing pipe length and loading duty. And the operation status and cycle change process of the A/C system were investigated using some experimental data and P-h diagrams. In long pipes, the pressure drop increases and the operating load on the compressor increases. Additionally, at the same loading duty, cooling capacity and COP decrease and the compressor discharge temperature increases. As loading duty increases, cooling capacity and compressor power consumption increase. Since the temperature deviation between the experimental value and the correlation equation for the discharge temperature of the long-pipe compressor shows a maximum of 10.5℃(50m, L/D : 20/0), the existing correlation equation needs to be modified.

In this study, the heating performance of a variable capacity A/C system was experimentally studied. A psychrometric calorimeter was used to obtain performance data of the A/C system using PWM(pluse width modulation) method and compare it with the compressor discharge temperature correlation equation. Heating capacity, COP, and compressor discharge temperature were obtained by changing indoor and outdoor temperatures, refrigerant amount, and loading duty. The following results were obtained by selecting 5 types of refrigerant amount, 3 types of outdoor temperature (fixed indoor temperature), and 2 types of loading duty. As the outdoor temperature increases, heating capacity and COP increase. Heating capacity was affected by both outdoor temperature and loading duty. However, COP was more influenced by outdoor temperature. The effect of increasing the amount of refrigerant on the performance of the A/C system was not significant. Additionally, the temperature deviation between the existing compressor discharge temperature correlation equation and the heating experiment data was about 5.1℃ at the maximum loading duty.

In this study, the cooling performance of a variable capacity A/C system was experimentally studied. A psychrometric calorimeter was used to obtain performance data of the A/C system using the pulse width modulation method and compare it with the compressor discharge temperature correlation equation. Cooling capacity, COP, and compressor discharge temperature were obtained by changing indoor and outdoor temperatures, refrigerant amount, and loading duty. The following results were obtained by selecting 5 types of refrigerant amount, 3 types of outdoor temperature (fixed indoor temperature), and 2 types of loading duty. As the outdoor temperature increased, cooling capacity and COP according to outdoor conditions decreased. And the higher the loading duty, the greater the cooling capacity, but the COP was minimal. The change in cooling capacity and COP due to the increase in refrigerant amount was not significant. Additionally, the change in compressor discharge temperature is more influenced by the outside temperature than by the loading duty.

PURPOSES : LED based Variable Message Signs(VMS) have been widely used to inform safety messages to the drivers in advance. Legibility Distance of VMS is the most important factor to provide the safety messages to drivers in timely and effective way. However, current National Standards on legibility distance design considers letter size only even there is a difficulty to read the signs at adverse weather conditions such as heavy fog. So, this study examined the legibility issue under fog by evaluating the legibility distance with two design factors such as letter size and luminance. METHODS : Two foggy weather conditions, intermediate and heavy fog, were simulated at real-road-scale Proving Ground. Legibility distance at daytime and nighttime was evaluated by test subjects. Subjects were asked to fill the legible distance on the test sheet and statistical significant was analysed at the lab. RESULTS : The legibility distance(LD) under fog was observed only 22 to 41% of LD observed under normal weather condition at daytime, and 26 to 45% at nighttime condition. Study results showed a consistent increase in LD with higher luminance even at same letter size and vice versa conditions, However, statically significant difference between groups was only revealed when both letter size and luminance level increased conditions. In order to apply the test results in terms of engineering benefits, LD results from significantly different groups was evaluated with relative to Stopping Sight Distance(SSD) within conceptual frame suggested in this study. CONCLUSIONS : From the study results, current National Standard on legibility distance design needs to consider letter size and luminance simultaneously to response the legibility issue in adverse weather conditions.

국제적인 선박 배출 가스에 대한 환경 규제가 점차 강화됨에 따라 전기추진 및 하이브리드 추진선박에 대한 관심이 증대되고 있으며, 이러한 선박에 적용하기 위한 다양한 솔루션이 개발 및 적용되고 있는데 특히 전력계통의 안정화, 시스템의 효율성을 높이기 위 한 방안으로 직류배전시스템이 적용되고 있다. 또한, 선박용 직류배전시스템에 대한 안전 및 성능에 대한 검증 및 시험의 중요성이 요구 되고 있다. 본 연구는 직류배전 테스트베드 구축 및 직류배전(가변속 발전)시스템에 대한 성능을 검증하고 연료소모량 분석한 결과로서 선박용 직류배전에 적용되고 있는 가변속 발전시스템을 적용하였으며, 발전기에서 출력되는 전력을 정류기를 통해 직류전력으로 변환하 여 시스템에 연계하고 이러한 장치들을 감시 및 제어하기 위한 시스템을 개발하였다. 이러한 직류배전 시스템을 적용한 시험을 통해 최 대 전압은 751.5V이고 최소전압은 731.4V가 계측되어 전압변동률은 2.7%로 3% 이내에서 안정적으로 전압이 공급되는 것을 확인하였고 부 하변동에 따라 가변속 발전시스템을 적용하였을 경우 연료소모량이 기존 정속발전시스템과 비교하여 구간에 따라 최대 20%이상 연료절 감이 되는 것을 시험을 통해 확인하였다.