• 한국군사과학기술학회지
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• 제23권1호
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• pp.18-27
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• 2020

In order to estimate the launch point of a high-speed vehicle, predicting the various characteristics of the vehicle's movement, such as drag and thrust, must be preceded by the estimation. To predict the various parameters regarding the vehicle's characteristics, we build the IMM filter specialized in predicting the parameters of the post-launch phase based on flight dynamics. Then we estimate the launch point of the high-speed vehicle using Inverse Dynamics. In addition, we assume the arbitrary error level of the radar for accuracy of the prediction. We organize multiple-dimensioned IMM structures, and figure out the optimal value of parameters by comparing the various IMM structures. After deriving the optimal value of parameters, we verify the launch point estimation error under certain error level.

• 대한한방부인과학회지
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• 제19권3호
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• pp.203-213
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• 2006

Purpose : This study was carried out to evaluate correlation between Bone Mineral Density(BMD) and degenerative lumbar disease in postmenopausal low back pain patients. Methods : 69 postmenopausal patients with low back pain were examined. Magnetic resonance imaging was performed to evaluate degenerative lumbar disease and bone mineral density of lumbar spine was measured by Dual energy X-ray absorptiometry. Data were analyzed by Pearson's Linear Correlation Coefficient. Results : In postmenopausal patients with low back pain, BMD(T-score, Z-score) had negative correlation with the grade of intervertebral disc herniation and positive correlation with weight. Other lumbar diseases including Spinal stenosis, Spondylolisthesis and Facet joint arthrosis didn't have significant correlation with BMD. Conclusion : In postmenopausal patients with low back pain, BMD(T-score, Z-score) had inverse relationship with the grade of intervertebral disc herniation.

• Journal of Chest Surgery
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• 제32권2호
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• pp.151-157
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• 1999

배경: 많은 실험적인 연구에서 종양 조직 내의 아포프토시스와 미세 혈관의 생성은 서로 반비례한다고 보고된다. 비소세포 폐암 조직내에서 두 수치의 관계를 조사하여 보았다. 대상 및 방법:조직내의 아포프토시스의 정도는 deoxynucleotidyl trasferase방법으로(Apop Tag In Situ Apoptosis Detection Kit, ONCOR) 측정하였고, 종양내 미세 혈관 밀도는 항 CD 31 항체를 이용하였다. 결과:아포프토시스 지수와 종양내 미세 혈관 밀도 사이에는 통계적으로 유의하게 역 상관관계가 있었다(p = 0.047). 결론: 비소세포 폐암종에서 아포프토시스와 미세 혈관 생성의 정도는 서로 연관이 있다고에 할 수있다. 그리고 종양내의 신생 혈관의 생성이 종양내 아포프토시스의 억제에 기여한다고 유추 할 수 있다.

• 한국전자통신학회논문지
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• 제10권3호
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• pp.395-402
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• 2015

본 논문에서는 곤충형 다리 구조를 갖는 4족 로봇의 정적 계단 보행 시 계단과의 충돌 제약이 없는 효율적인 걸음새 궤적 생성 방법을 제안한다. 우선 4족 로봇의 순기구학 및 역기구학 모델을 각기 대수학적 방법과 기하학적 방법으로 유도한다. 제안한 방법에서는 보행 시작 위치에서 수직 상승 후 사인 파형의 계단 보행 궤적을 생성하고, 계단과의 충돌을 피하기 위한 보행 궤적의 계수를 설정한다. 또한 안정적인 계단 보행을 위한 걸음새 순서를 결정한다. 마지막으로, 컴퓨터 시뮬레이션을 통해 제안한 계단 보행 방법의 효용성 및 실제 적용 가능성을 검증한다.

• Journal of Power Electronics
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• 제17권1호
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• pp.262-271
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• 2017

This paper studies the performances of five typical Phase-locked Loops (PLLs) for distorted and unbalanced grid, which are the Decoupled Double Synchronous Reference Frame PLL (DDSRF-PLL), Double Second-Order Generalized Integrator PLL (DSOGI-PLL), Double Second-Order Generalized Integrator Frequency-Lock Loop (DSOGI-FLL), Double Inverse Park Transformation PLL (DIPT-PLL) and Complex Coefficient Filter based PLL (CCF-PLL). Firstly, the principles of each method are meticulously analyzed and their unified small-signal models are proposed to reveal their interior relations and design control parameters. Then the performances are compared by simulations and experiments to investigate their dynamic and steady-state performances under the conditions of a grid voltage with a negative sequence component, a voltage drop and a frequency step. Finally, the merits and drawbacks of each PLL are given. The compared results provide a guide for the application of current control, low voltage ride through (LVRT), and unintentional islanding detection.

• Transactions on Electrical and Electronic Materials
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• 제8권1호
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• pp.26-31
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• 2007

The goal of this study is to determine if High Pressure Micro Jet (HPMJ) conditioning can be used as a substitute for, or in conjunction with, conventional diamond pad conditioning. Five conditioning methods were studied during which 50 ILD wafers were polished successively in a 100-mm scaled polisher and removal rate (RR), coefficient of friction (COF), pad flattening ratio (PFR) and scanning electron microscopy (SEM) measurements were obtained. Results indicated that PFR increased rapidly, and COF and removal rate decreased significantly, when conditioning was not employed. With diamond conditioning, both removal rate and COF were stable from wafer to wafer, and low PFR values were observed. SEM images indicated that clean grooves could be achieved by HPMJ pad conditioning, suggesting that HPMJ may have the potential to reduce micro scratches and defects caused by slurry abrasive particle residues inside grooves. Regardless of different pad conditioning methods, a linear correlation was observed between temperature, COF and removal rate, while an inverse relationship was seen between COF and PFR.

• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 2006년 제4회 한국유체공학학술대회 논문집
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• pp.209-212
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• 2006

Insect and birds in nature flap their wings to generate fluid dynamic forces that are required for the locomotion. Most of the previous published papers discussed mainly on the effect of flapping parameters such as flapping frequency and amplitude on the thrust at a fixed Reynolds number. However, it is not much known on the values of the flapping parameters that the flapping wing requires to generate the thrust at the low Reynolds number flow. In this paper, the onset of the thrust generation is investigated using the lattice Boltzmann method. The wake patterns and velocity profiles behind a flat plate in heaving oscillation are investigated for the heaving amplitude of 0.5C. The time-averaged thrust coefficient value is investigated by changing the reduced frequency from 0.125 to 3.0 for three values of heaving amplitude (h/C=0.25, 0.325, 0.50). It is also found that the critical Strouhal number over which the flat plate starts to produce the thrust is around 0.1 and the thrust is an exponential function of the Strouhal number.

• Child Health Nursing Research
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• 제9권2호
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• pp.198-205
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• 2003

Purpose: The purpose of this study is to investigate the degree of school children's internet addiction and to explicit the relationship among the internet addiction, family environment and school adjustment. Method: The subjects of the study were 640 students from 5th and 6th year children of five elementary schools in G city. The data were analyzed by SAS program with frequency, percentage, means, standard deviation, χ² -test, ANOVA and Pearson's Correlation Coefficient. Result: In the degree of the internet addiction were 10.0％ of addiction group, 58.0％ of intermediate group, and 32.0％ of nonaddiction group. There were significant differences in family environment score(F=25.09, p=.0001) and school adjustment score(F=34.46, p=.0001) regarding internet addiction degree. The relationship among internet addiction score, family environment score and school adjustment score revealed a significant inverse correlation(r=-0.32, p=.0001, r=-0.35, p=.0001). And the relationship between family environment score and school adjustment score revealed a significant correlation(r=0.52, p=.0001). Conclusion: The degree of school children's internet addiction has been found to be very high and correlated to the family environment and school adjustment. Therefore, programs should be developed in order to improve this situation.

• 한국전산구조공학회논문집
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• 제15권1호
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• pp.137-146
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• 2002

본 연구에서는 복합재료 원통쉘의 정적 구조해석 결과를 신경회로망에 적용하여 원통쉘에 가해진 하중특성을 추론하였다. 신경회로망 알고리즘은 역전파 학습법의 학습율이 가변적으로 조정될 수 있도록 프로그램을 개발하였으며, 입력패턴은 원통쉘에 하중이 가해졌을 때, 원통쉘의 측면에서 발생하는 9지점의 변형률을 이용하였다 출력층은 가해진 하중특성으로 설정하였으며, 학습결과 원통쉘의 하중특성 추론 학습에 성공하였다. 은닉층의 층수를 1층에서 3층까지 학습결과를 비교분석하였으며, 하중특성은 0.5% 이내로 추론이 가능해졌다. 본 연구 결과 신경회로망을 이용한 복합재료 원통쉘의 역공학이 가능해졌다.

• 기본간호학회지
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• 제10권3호
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• pp.316-325
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• 2003

Purpose: This study was done to identify role conflict and job satisfaction in nurses in oriental medicine hospitals. Method: Study participants were 128 nurses employed in oriental medicine hospitals. The data were collected using a survey questionnaire. The instruments included a 37-item role conflict scale and 20-item job satisfaction scale. The data were analyzed using frequencies, means, percentages, t-test, ANOVA, and Pearson correlation coefficient with the Window's SPSS program. Result: There were significant differences in job satisfaction according to marital status, motivative for being a nurse and length of work time. The mean score for role conflict was 3.69 and for job satisfaction, 2.96. Job satisfaction had a significant inverse correlation with role conflict in these nurses. Conclusion: It is suggested that further studies are needed to identify factors affecting role conflict and job satisfaction in oriental medicine nurses, which will help to identify strategies to decrease the role conflict and increase job satisfaction in nurses employed in oriental medicine hospitals.