• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2017.04a
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• pp.76-76
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• 2017

4륜 승용관리기는 보통 후방이나 전방에 작업기를 장착하여 작업하나 3륜 승용관리기는 작업기를 복부에 장착함으로 작업의 정밀도, 편이성, 관측의 용이성 향상과 함께 지상고 제고, 차폭 조절, 조향 등의 성능 개선을 기할 수 있다. 국내에서는 3륜 승용관리기용 복부 장착 부속작업기가 거의 개발되어 있지 않으며, 특히 두류 재배에 있어서 일관기계화 작업을 위한 관리작업기의 개발이 매우 필요한 실정이다. 승용관리기의 중경배토기에 의한 작업은 기존 인력에 의한 작업보다 약 87%의 노력을 절감할 수 있으며, 잡초방제 효과도 인력에 비하여 크게 떨어지지 않고, 수량도 증가하는 것으로 보고되고 있다. 따라서 본 연구는 3륜 승용관리기에 적합한 복부장착형의 중경배토기를 설계 제작하였다. 3륜 승용관리기용 중경배토기는 승용관리기의 복부 PTO에서의 구동력 전달을 위한 연결 조인트, 중간축, 기어 및 체인 전동기구, 구동축으로 구성된 동력전달부, 4개의 로타리 날과 후방 1개의 배토날로 구성된 3조의 작업날, 로타리 날과 배토날의 경심 조절을 위한 3조의 바퀴, 흙의 비산 방지를 위한 로타리날 커버 및 케이스, 다양한 조간거리에 적응을 위한 조간조정 나사부, 3륜 승용관리기에의 부착을 위한 프레임 및 부착보조 작업기 이동용 바퀴장치 등으로 구성 설계 제작하였다. 로타리 날과 배토날은 기존 시판 관리기용 날을 사용하였다. 로타리 날은 진행방향으로 회전하도록 하였으며, 날의 회전반경은 약 330 mm, 조당 경운 폭은 약 230 mm 설계하였다. 최대 경심은 100 mm이며, 조간거리의 조절범위는 수동 나사에 의하여 620~900 mm 범위로 무단조절 할 수 있도록 하였다. 중경제초기는 3륜 승용 관리기 복부의 평행링크에 부착되므로 작업기의 이동 및 부착 편이를 위하여 이동용 바퀴를 설치하였다. 제작된 중경배토기의 크기는 길이${\times}$폭${\times}$높이가 $660{\times}2072{\times}880mm$, 중량은 약 200 kg으로 제작되었다.

• Journal of Yeungnam Medical Science
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• v.4 no.1
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• pp.33-42
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• 1987

Congenital origin intestinal obstruction are important disease due to required emergency operation. So accurate and rapid diagnosis is needed for decreased mortality and morbidity. Radiologist must detect to accurate obstruction site and also associated other congenital anomalies. And also embriological bases are very important role to the diagnosis of theses diseases. We were analysed radiologically and clinically 25 cases with congenital origin intestinal obstruction with review of literature. 1. Hypertrophic pyloric stenosis 6 cases, midgut malrotation 4 cases, congenital megacolon 8 case, imperforated anus 5 cases, ileal atresia 1 case and duodenal atresia 1 case. 2. Male and female radio were 16:9. Especially on hypertrophic pyloric stenosis, 5 cases were male infants. 3. All cases of hypertrophic pyloric stenosis represented string sign and also pyloric beak sign shoulder sign on UGI. 4. I case duodenal atresia showed double bubble sign on simple abdomen x-ray and ileal atresia showed mechanical small bowel obstruction sign with microcolon. 5. On midgut malrotation, cecum was located in right upper abdomen on 4 cases. And 2 cases were associated with Ladd's band. I case with volvulus and 1 case with mesenteric defect. 6. Involved site of all congenital megacolon were localized to rectosigmoid colon. 7. On 5 cases imperforated anus, 3 cases were low type and 2 case high type. Rectoperineal and rectourogenital fistula were demonstrated on 4 cases.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.9 no.3
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• pp.12-19
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• 2010

In road network, especially in urban area, inefficiency of travel time is caused by signal control and turn maneuver at intersection and this inefficiency has substantial effects on travel time. When searching for the shortest path, this inefficiency which is caused by turn maneuver must be considered. Therefore, travel time, vehicle volume and delay for each link were calculated by using simulation package, PARAMICS V5.2 for adaptation of turn penalty at 16 intersections of Gangnam-gu. Turn penalty was calculated respectively for each intersection. Within the same intersection, turn penalty differs by each approaching road and turn direction so the delay was calculated for each approaching road and turn direction. Shortest path dealing with 16 intersections searched by Dijkstra algorithm using travel time as cost, considering random turn penalty, and algorithm considering calculated turn penalty was compared and analyzed. The result shows that by considering turn penalty searching the shortest path can decrease the travel time can be decreased. Also, searching the shortest path which considers turn penalty can represent reality appropriately and the shortest path considering turn penalty can be utilized as an alternative.

• Transactions of the Korean Society of Mechanical Engineers
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• v.16 no.4
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• pp.737-752
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• 1992

Analysis of elasto-dynamic deformation of flexible linkage mechanism is conducted using the finite element method. The equations of motion of the system are derived from the static structural problem in which dynamic inertia, gravitational and driving forces are treated as external loads. Linear spring model is included in the formulation of equation of motions to represent the effects of deformation of elastic bearings of revolute joints on the system behavior. A computer program is constructed and applied to analyze a specific crank-lever 4-bar mechanism. The algorithm of the program is as follows. First, the natural frequencies and the mode shapes of the system are calculated by solving the eigenproblem of the mechanism system which can be considered as a static structure by assuming the input shaft (crank shaft) to be fixed at any given configuration of mechanism. And finally, the elasto-dynamic deformation of the whole system is obtained using mode superposition method for the case of constant input speed. The effect of geometric stiffness on the mechamism is included in the program with the axial forces of links obtained through the quasi-static displacement analysis. It is found that the geometric stiffness exerts an important effect upon the elasto-dynamic behavior of the flexible linkage mechanism. Elastic deformation of bearing lowers the natural frequencies of the system, resulting smaller elastic displacement at the mid-point of the links and bigger elestic displacement at the ends of the links than rigid bearing. The above investigation of flexible linkage mechanism shows that the effects of the elastic deformation of bearing on the mechanism should be considered to design the mechanism which satisfies more preciously the purpose and the condition of design.

• Journal of Korean Tunnelling and Underground Space Association
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• v.10 no.3
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• pp.303-312
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• 2008

Multi-axial compression tests have been frequently adopted for the evaluation of material properties of rock cores and rock fracture model tests. Special care has to be applied on the boundary condition between the specimen and loading platen to draw the precise test results of the multi-axial compression tests. With the use of dry steel platen, the stress rotation will occur, due to the frictional restraint from the boundary between the specimen and loading platen. The restraint will deviate the expected test results under the conditions of the given external pressures. Various methods have been applied to reduce the side restraint along the specimen/loading platen interface. The steel brush type loading platen is one example of the attempts. In this paper, a new type of loading platen is introduced to overcome the limitation caused by the use of the brush type loading platen, which requires some internal space for the installation of the brushes. The new type of loading platen, roller supported steel piston type loading platen. is constituted of shot steel pistons which have sufficient stiffness to deliver the external pressure and the shaft type roller installed at the rear of the pistons. The pistons are designed to follow the local deformation of the specimens. In this paper, structural details of the loading platen are presented and frictional and biaxial compression tests results are shown to verify the required functions of the loading platen. Furthermore, calibration process is followed by a comparison between the test results and numerical analyses.

• Journal of Dental Rehabilitation and Applied Science
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• v.26 no.4
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• pp.419-432
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• 2010

Various torque generating devices have been developed and employed to apply a proper torque. These devices are usually calibrated by the manufacturer to apply appropriate torque levels for their specific implants and attachments. The purpose of this investigation was to determine and compare the accuracy of the torque controllers. In this study, 4 types of torque controllers were used; torque limiting device(TLD), torque indicating device(TID) and contra angle torque driver(CA), electronic torque controller(ETC). Digital torque gauge was employed to measure the de-torque value. Thirty cycles of tightening and loosening were repeated with each torque controller. All implant torque controllers have shown slight errors and deviations. The contra angle torque driver exhibited the most accurate data. In the limitation of this study, it would be recommended that the implant torque controllers should be checked whether uniformed and precise torque can be generated and a measuring error should be corrected.

• Journal of the Korean Society for Marine Environment & Energy
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• v.19 no.2
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• pp.120-128
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• 2016

This paper describes power generation from sea waves by using linear permanent magnet generator. A buoy is placed on the ocean surface and connected to the generator. The wave energy is carried out from the movement of a buoy. An electrical conversion system is needed between the generator and the grid. For an analysis of the power system, the modeling of the linear generator and converter system was proceeded. This paper proposes vector control method for wave power generation system using linear generator. In order to verify the proposed method, simulation and experiment performed and the results support the validity of the control scheme.

• The Journal of Engineering Geology
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• v.10 no.2
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• pp.18-35
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• 2000

The most dominant type of landslide in Korea is debris flows which mostly take place along mountain slopes during the rainy season, July to August. The landslides have been reported to begin activation when rainfall is more than 200mm within 2days. The debris flows are usually followed by translational slips which occur upper part of mountain slopes and they transit to debris flow as getting down to the valleys. Lithology, location, slope inclination, grain size distribution of soil, permeability, dry density and porosity have been proved as triggering factor causing translational slides. The triggering data taken from mapping are statistically analysed to get landslide potential quantitatively. Rock mass creeps mostly occur on well bedded sedimentary rocks in Kyeongsang Basin. Although the displacement of rock mass creep is relatively small about 1m, the creep can cause severe hazards due to relatively large volume of the involved rock mass. Examples are rock mass creep occurred in the mouth of Hwangryongsan Tunnel, in Chilgok and in Sachon in 1999. Although the direct factor of the creeps are due to slope cutting at the foot area, more attention is required A rotational slide occurring within thick soil formation or weathered rock is also closely related to bottom part of slope cutting. It is propagated circular or semi-circular type. Especially in korea, the rotational slide may be frequently occurred in Tertiary tuff area. Because they are mainly composed of volcanic ash and pyroclastic materials, well developed joints and high degree of swelling and absorption can easily cause the slide. The landslide among the Pohang-Guryongpo national road is belong to this type of slide.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.4
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• pp.2344-2349
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• 2015

In Korea, summer is hot and humid, and air-conditioners consume too much electricity due to large amount of latent heat. Simultaneous usage of dehumidifier may reduce the latent heat and save the electricity. In this study, dehumidification performance was measured in a constant temperature and humidity chamber for a small-sized dehumdification rotor made of inorganic fiber impregnated with metallic silicate. Variables were rotor speed, room temperature, regeneration temperature, room relative humidity and frontal velocity to the rotor. Results showed that there existed optimum rotor speed (1.0 rpm), and optimum regeneration temperature ($100^{\circ}C$). Above the optimum rotor speed, incomplete regeneration is responsible for reduced dehumidification. Above the optimum regeneration temperature, increased temperature difference between regeneration and dehumidification process is responsible for reduced dehumidification. The amount of dehumidification also increases with the increase of relative humidity, dehumidification temperature and flow velocity into the rotor.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.31 no.4
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• pp.221-228
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• 2019

Experimental investigation was performed to analyze the flow field characteristics and power generation performance for a shroud tidal power generation system. Electrical power output was compared with the rotational speed of the turbine blade and electric load connected to the generator for various flow velocity. As the electrical load decreased, the speed of the turbine increased rapidly and reached by about 2 times. The power output also increased remarkably with the decrease of load, and then decreased after maximum power point. In addition, the maximum power point appeared at high electrical loads as the experimental flow velocity increased. These results of the flow field characteristics and power generation performance analysis of the shroud tidal power generation system variation with the flow velocity conditions and electrical load are expected to be the basic data necessary for the development of efficient shroud tidal power generation system.