• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 1999년도 춘계학술대회논문집
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• pp.39-44
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• 1999

Hydroforming is a forming process enabling circular metal tubes to be produced in complex cross sections along curved axial paths With the availability of advanced machine design and control They offer advantages over stamped sheet metal in lower tooling cost and structural mass The technology is relatively new so that there is no large knowledge base to assist the fundamentals of tube hydroforming technology. The purpose of this paper is found that adaptive bending condition and contact condition for bended part has uniform thickness distribution.

• Communications for Statistical Applications and Methods
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• 제2권2호
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• pp.146-154
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• 1995

By using simple Taylor expansion, we derive an easy bias-correction rule for the apparent prodiction error of the predictor defined by the general M-estimators with respect to an arbitrary measure of prediction error. Our method has a considerable computational advantage over the previous methods based on the resampling thchnique such as Cross-validaton and Boothtrap. Connections with AIC, Cross-Validation and Boothtrap are discussed too.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2010년도 추계학술대회 논문집
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• pp.229-230
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• 2010

• 한국안전학회지
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• 제19권1호
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• pp.60-65
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• 2004

The PVC insulated flexible cords are used mainly as power supply cords of electric appliance. This electric wire is a stranded wire consisted of dozens of strands. In case stranded wires are disconnected by mechanical stress, it weakens electrically. Finally, the over current flows through stranded wires, and electrical fire occurs. In this study, we analyzed the melting properties of strands by over current, such as melting process, melting current and melting time. And we analyzed that quantity of heat for melting, a cross sectional structure, and surface structure by optical microscope and SEM. As analysis results, melting time decreased as melting current increased. And quantity of heat for melting was low, too. From the cross sectional structure of melted wire, when a melting current low and melting time long, it was found that the dendrite structure grew. However, the dendrite structure is hard to grow because growing time is not enough when a melting current high and melting time short.

• 한국문헌정보학회지
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• 제31권3호
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• pp.165-208
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• 1997

온라인 열람목록의 이용자 인터페이스 특성이 이용행태에 미치는 영향을 파악하고, 이용자에게 보다 친근한 인터페이스를 평가하여 시스템 설계의 방향을 제시하는 데에 본 연구의 목적을 두었다. 이용자 인터페이스에 있어서 뚜렷한 특성상의 차이를 보이는 두 시스템을 대상으로 하여 $2\times2$ 교차계획법으로 이용행태연구를 위한 실험연구를 수행하였다. 65명의 탐색자가 실험에 참여하였다. $2\times2$ 교차계획법에서의 이월효과와 시스템효과, $\chi^2$검증, t 검증 매크네마 검증, 최대우도법을 통한 주변대칭성 검증, 인자분석, 회귀분석, 분산분석 등의 통계기법을 검증해야 할 가설과 데이터의 성격에 따라 적절히 적용하여 분석하였다.

• 한국의학물리학회지:의학물리
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• 제15권1호
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• pp.17-22
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• 2004

Multileaf collimator (MLC) is now rapidly replacing the lead ahoy block to shape the radiation treatment field. In addition to its defect of rectangular field shaping and increased penumbra width, it has another possible problem, and that is of radiation transmission between leaves, which needs to be maintained at as low a level as is permissible. The authors measured and analyzed the inter-leaf and cross-leaf transmissions of MLC by Varian Associates Inc, before its clinical application. The inter-leaf and cross-leaf transmissions were calculated by comparing the measured point doses in the polystyrene phantom in the open field and in a total closure of MLC. The beam profile of the inter-leaf and cross-leaf transmissions were depicted by using a water phantom. A photon beam of 6 MV was used in the measurement. The inter-leaf transmission was 1.63∼1.67%, indicating that the shielding effect of MLC is excellent. However, the cross-leaf transmission in the central area was 18.4∼18.7% and this is well over the clinically acceptable limitation of 5%. The beam profile of cross-leaf transmission displayed 80∼90% transmission near the field edge, so that the cross-leaf transmission was 14∼17% in this area. The multileaf collimator has an excellent shi디ding effect and the inter-leaf transmission is negligible so that it can be used in clinic as a good replacement of the conventional lead alloy block. However, care must be taken to avoid the cross-leaf transmission in the radiation field.

• 한국초전도ㆍ저온공학회논문지
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• 제19권3호
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• pp.44-48
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• 2017

Current lead is a device that connects the power supply and superconducting magnets. High temperature superconductor (HTS) has lower thermal conductivity and higher current density than normal metal. For these reasons, the heat load can be reduced by replacing the normal metal of the current lead with the HTS. Conventional HTS current lead has same cross-sectional area in the axial direction. However, this is over-designed at the cold-end (4.2 K) in terms of current. The heat load can be reduced by reducing this part because the heat load is proportional to the cross-sectional area. Therefore, in this paper, heat load was calculated from the heat diffusion equation of HTS current leads with uniform and non-uniform cross-sectional areas. The cross-sectional area of the warm-end (65K) is designed considering burnout time when cooling system failure occurs. In cold-end, Joule heat and heat load due to current conduction occurs at the same time, so the cross-sectional area where the sum of the two heat is minimum is obtained. As a result of simulation, current leads for KSTAR TF coils with uniform and non-uniform cross-sectional areas were designed, and it was confirmed that the non-uniform cross-sectional areas could further reduce the heat load.

• 한국안전학회지
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• 제33권5호
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• pp.15-20
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• 2018

This paper describes the fusing time characteristics of Light PVC Sheathed Circular Cord(VCTF) and Tray Frame Retardant(TFR) cables according to increased temperature under over current condition. The experimental equation will be used to determine the validity and reliability of the test results. The over current flowed 3, 5 and 10 times higher than the amount of allowable current using DC power supply with DAQ(Data Acquisition) measurement system. An infrared radiation heater, which was controlled by a variable AC auto transformer, was used to increase the temperature from room temperature to 50, 100 and 150 degrees Celsius. First, two type of cables were analyzed those with different cross-sectional areas with in the same structure and those with different structures with in the same cross-sectional areas. Then, it was determined how fusing time had been influenced according to the cross-sectional areas and different structures, respectively. The cable resistance was increased by joule heating according to increasing temperature. Therefore, the allowable current of cable is decreased. Finally, the fusing time of the cable was decreased due to increased temperatures at current flow, which were 3 times the amount of allowable current. The instantaneous breakdown was observed when current flow was 5 and 10 times over the amount of allowable current. The fusing time is directly affected by the structure of cable insulation.

• Nutrition Research and Practice
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• 제10권6호
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• pp.590-596
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• 2016

BACKGROUND/OBJECTIVES: The purpose of this study was to examine whether plasma lipid profiles are affected differently by snack kinds with equal calorific values. SUBJECTS/METHODS: We compared a Korean traditional confectionery (dasik) with Western confectionery (cookie) in this regard. Controlled cross-over study consisted of two 3-week snack intake phases and for separating, a 2-week washout period (3-2-3) was carried out with 30 healthy women aged between 40-59 years old. Brown rice based Korean traditional confectionery and wheat flour based Western confectionery were used. The participants consumed either dasik or cookie every day for 3 weeks, providing 93 kcal a day. RESULTS: The total cholesterol (TC) in the dasik group had decreased significantly after 3 weeks (P < 0.05). Furthermore, in the dasik group, reduction in TC and low-density lipoprotein-cholesterol were greater than those in the cookie group (P < 0.05). CONCLUSIONS: Prioritizing functional snacks like dasik improves plasma lipid profiles; this may be useful information for individuals who cannot refrain from snacking.

• 한방재활의학과학회지
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• 제29권1호
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• pp.63-73
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• 2019

Objectives The purpose of this study is to evaluate the safety of Ojeok-san extract powder and soft extract in healthy male volunteers. Methods Randomized controlled, cross over study was carried out in healthy male volunteers. Total 27 of 31 subjects meeting the inclusion criteria were enrolled and three subjects for waiting were included. To each group 12 subjects were randomly allocated by random number table. Group A took the extract powder in the first period and then took the soft extract in the second period. Group B took the medicine in the opposite order. Trial was conducted through two times of hospitalizations and all subjects had a seven-days of wash out period. Vital sign and laboratory test were checked before and after the medication. The mean difference of safety evaluation variables were analyzed by paired t-test (p<0.001) or wilcoxon signed rank test (p<0.05). The mean difference between two groups were analyzed by independent t-test (p<0.05) or Mann whitney test (p<0.05). Results As a result of all data related to vital sign and laboratory test in both group, There were no significant differences associated with the clinical trial drug between before and after the medication. And there was no adverse event associated with the clinical trial drug. Conclusions Both Ojeok-san extract powder and soft extract were found to be safe for healthy male volunteers.