본 연구는 2018년부터 2022년 상반기까지 약 5년간 노인 수중운동 프로그램과 관련하여 운동 프로그램을 적용한 국내 선행 문헌 14편을 연구대상으로 선정하여 특성, 운동프로그램 기간, 구성, 효과에 대해 분석하였고 결과는 다음과 같다. 국내 KCI등재지에서 발행된 선행문헌을 대상으로 분석하였고 결과 는 다음과 같다. 첫째, 성별에서는 여성노인을 대상으로 한 연구가 대부분이었고 연령은 65세 이상, 그리고 피험자 수는 50명 이하, 그리고 건강상태는 대부분 건강한 노인들을 대상으로 한 논문들이었다. 둘째, 수중 운동 프로그램 적용 기간은 8주-12주 미만, 주당 운동 횟수는 3-4번, 그리고 1회 운동 시간은 60분 미만 과 60분을 적용한 운동프로그램이 대부분이었다. 셋째, 수중운동 프로그램 구성 내용에서는 유산소 운동프 로그램으로 구성한 논문들이 대부분이었다. 넷째, 체력 요인, 심리적 요인, 신체조성 요인, 혈액성분 요인, 기타 요인 등 수중운동적용 효과가 있음을 확인하였다.

In this study, the thermal equilibrium of a motor operated in the sea and the temperature in the equilibrium were studied. To predict the equilibrium temperature in the sea, the cooling performance of the motor was studied by comparing results of analysis and experimental results in the air condition. By this study, the method of prediction of the cooling performance of a motor in various environments could be useful.

본 연구의 목적은 12주간 수중걷기운동이 비만 노인 여성의 신체조성, hs-CRP, HOMAIR 및 혈압에 미치는 영향을 알아보기 위하여 실시하였다. 체지방률 30% 이상인 비만 노인 여성 중 운 동군(10명), 대조군(10명)으로 총 20명으로 실시하였으며, 모든 검사항목은 동일한 방법과 조건으로 신 체조성, hs-CRP, HOMA-IR 및 혈압을 사전, 사후 총 2회 측정하였다. 수중걷기운동은 12주간, 주 3 회, 1회 50분, RPE 11-14 강도로 실시하였다. 측정변인에 대해 평균값과 표준편차(M±SD)를 산출한 후 사전 운동군과 대조군의 신체적 특성과 각 측정변인에 대한 동질성 검정을 위하여 독립 t-test를, 집 단 내의 사전·사후 평균치 변화에 대한 차이 검증은 종속 t-test를, 집단 간 차이에 대한 주효과 검정 및 집단 간 시기 간 상호작용 효과는 반복측정 분산분석을 이용하였다. 본 연구결과 운동군에서 신체조성, 체지방률(p<.05), 인슐린(p<.01), HOMA-IR(p<.01) 및 수축기 혈압(p<.05)이 유의하게 감소하였다. 따 라서 수중걷기운동이 비만 노인 여성의 비만 및 심혈관질환의 개선에 도움을 줄 수 있을 것으로 사료 된다.

The purpose of this study was to compare the efficiency of air and oxygen injected into the underwater non-thermal dielectric barrier discharge plasma (DBD plasma) device used to remove five types of antibiotics (tetracycline, doxycycline, oxytetracycline, clindamycin, and erythromycin) artificially contained in the fish farm discharge water. The voltage given to generate DBD plasma was 27.8 kV, and the measurement intervals were 0, 0.5, 1, 2, 4, 8, 16 and 32 minutes. Tetracycline antibiotics significantly decreased in 4 minutes when air was injected and were reduced in 30 seconds when oxygen was injected. After the introduction of air and oxygen at 32 minutes, 78.1% and 95.8% of tetracycline were removed, 77.1% and 96.3% of doxycycline were removed, and 77.1% and 95.5% of oxytetracycline were removed, respectively. In air and oxygen, 59.6% and 83.0% of clindamycin and 53.3% and 74.3% of erythromycin were removed, respectively. The two antibiotics showed lower removal efficiency than tetracyclines. In conclusion, fish farm discharge water contains five different types of antibiotics that can be reduced using underwater DBD plasma, and oxygen gas injection outperformed air in terms of removal efficiency.

Sea anchor for fishery is commonly used in jigging fishery and purse seine. The study of sea anchor was studied for improvement of opening efficiency and drag by changing the type of shape and the diameter of vent. However, standard specification of sea anchor is not set and has not been studied for underwater stability. Therefore, this study aimed to improve underwater stability of sea anchor by changing a vent diameter and weight of sinker. The experiment was conducted in flume water tank. The experiment model of sea anchor was made from actual model of sea anchor which is used in fishery by similarity law. The model of sea anchor was designed to different types of vent diameter and weight of sinker in different current speed. The value of movement of side to side (X-axis), drag of sea anchor (Y-axis) and movement of up and down (Z-axis) was measured for 30 seconds. Each value of X, Y, Z-axis was analyzed through t-test and ANOVA analysis to verify that each value had a significant difference according to the difference compositions. There was correlation between the movement of X-axis and Z-axis. The drag of sea anchor was stronger as the current speed increased. However, the larger the vent diameter, the weaker the drag. From the result of the standard deviation, the movement of X-axis was inversely proportional to the vent diameter. However, movement of Z-axis was larger as the weight of sinker was the heaviest or lightest from the result of the standard deviation. These results suggest that the sea anchor should be combined with proper size of the vent diameter and the weight of sinker to improve the stability.

선박, 잠수함이 추진하면 수중구조물 후류에 와류가 발생하고 이에 따른 와류기인 구조진동이 유발된다. 최근 선박, 잠수함의 고속화 및 대형화 추세에 따라 고차모드에서 유발되는 와류기인 진동 및 피로파괴에 대한 중요성이 강조되고 있다. 고속 유속환경의 와 류는 저속 유속환경 대비 큰 진동을 유발하므로 이에 관한 연구가 필요하다. 본 연구에서는 수중날개 고차모드에서 유발되는 와류기인 진동을 예측하기 위한 하이브리드 유체구조연성 해석 방법론을 제시하였다. 고차모드를 고려한 하이브리드 유체구조연성 해석을 수행하 여 와류기인 진동을 도출하고 실험결과와 비교함으로써 방법론을 검증하였다. 최종적으로 와류기인 진동으로부터 도출된 최대 von Mises 응력을 노르웨이 선급에서 제시한 S-N 선도에 적용함으로써 고차모드 유체구조연성 해석의 효용성을 확인하였다. 고차모드를 고려하여 와류기인 진동응답을 도출할 경우 유체구조연성에 의한 락인(Lock-in) 특성을 확인하였으며 고려하지 않은 경우 대비 진동응답과 최대 von Mises 응력에서 10배 이상의 차이를 보였다. 향후에는 외팔보 경계조건 및 형상에 대한 확장연구가 필요하다.

This study analyzed the wake characteristics of the rim-driven propeller (RDP) used in an underwater robot. For underwater robots to perform specific missions, not only propulsion characteristics but also wake characteristics must be considered. In this study, a blade was designed based on NAC 0012 with a symmetrical cross-section. The RDP was hubless with three or four blades. The influence of both the free water surface and the bottom was considered, and the wake was measured using a particle image velocimetry in the advance ratio of 0.2 to 1. Model 1 showed symmetrical wakes in the entire advance ratio section. Model 2 showed asymmetric wakes due to the influence of the free water surface and the bottom at low advance ratio.

Recently, the demand for atypical structures with functions and sculptural beauty is increasing in the construction industry. Existing mold-based structure production methods have many advantages, but building complex atypical structures represents limitations due to the cost and technical characteristics. Production methods using molding are suitable for mass production systems, but production cost, construction period, construction cost, and environmental pollution can occur in small quantity batch production. The recent trend in the construction industry calls for new construction methods of customized small quantity batch production methods that can produce various types of sophisticated structures. In addition to the economic effects of developing related technologies of 3D Concrete Printers (3DCP), it can enhance national image through the image of future technology, the international status of the construction civil engineering industry, self-reliance, and technology export. Until now, 3DCP technology has been carried out in producing and utilizing residential houses, structures, etc., on land or manufacturing on land and installing them underwater. The final purpose of this research project is to produce marine structures by directly printing various marine structures underwater with 3DCP equipment. Compared to current underwater structure construction techniques, constructing structures directly underwater using 3DCP equipment has the following advantages: 1) cost reduction effects: 2) reduction of construct time, 3) ease of manufacturing amorphous underwater structures, 4) disaster prevention effects. The core element technology of the 3DCP equipment is to extrude the transferred composite materials at a constant quantitative speed and control the printing flow of the materials smoothly while printing the output. In this study, the extruding module of the 3DCP equipment operates underwater while developing an extruding module that can control the printing flow of the material while extruding it at a constant quantitative speed and minimizing the external force that can occur during underwater printing. The research on the development of 3DCP equipment for printing concrete structures underwater and the preliminary experiment of printing concrete structures using high viscosity low-flow concrete composite materials is explained.