• 대한전자공학회논문지
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• 제26권5호
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• pp.1-9
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• 1989

2진 디지탈 전송시스템에서 보다 나은 전송효율을 얻기 위해서는 재역제한이 필요하다. 그러나 대역제한을 하는 경우 일반적으로 부호간의 간섭현상(ISI:intersymbol interference)이 발생되는데 본 논문에서는 최소의 부호간의 간섭현상과 최대의 저지대역 (stop band) 손실을 가진 대역제한 필터를 설계하기 위해 첫째, 2진 횡단선 필터(BTF:binary transversal filter)와 아나로그 필터를 결합시킴으로써 아나로그 필터를 이용하여 시간영역에서 2진 횡단선 필터에서 발생되는 구형펄스의 계단응답을 구해 부호간의 간섭현상이 최소가 되는 값을 찾았다. 둘째, 대역 제한을 위해 주파수영역에서 원하는 필터 특성과 오차를 최소화시켜 2진 횡단선 필터에서의 저항치(Tap계수)를 구해 최적필터를 설계하는 알고리듬을 제시하였다. 또한 저항치를 3, 5, 7개를 설정했을 경우 시뮬레이션 예를 보였는데 7개 설정했을 시는 약-30dB 정도의 리플(ripple)이 발생됨을 확인할 수 있었다.

• 한국소음진동공학회논문집
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• 제21권8호
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• pp.752-760
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• 2011

In tilting pad bearing design process, the selection of the proper configuration type of either a load-between-pad(LBP) or load-on-pad(LOP) as well as preload and pivot offset conditions is to be carefully considered. Also the bearing needs to be designed in order to be suited for the rotor-bearing system and operating condition. In this paper, it is observed that the dynamic characteristics in a five pad tilting pad bearing for the LBP and the LOP configurations are influenced by the variation of preload and pivot offset. In this context, rotor dynamic analysis of the 5 MW industrial gas turbine supported by the tilting pad bearing at the front and roller bearing at the rear is carried out based on the dynamic coefficients of the tilting pad bearing investigated. The result shows that two rigid body critical modes experience various changes according to the influence of the tilting pad bearing uniquely applied to one side of this machine. Mainly, the second critical speed, the rigid body mode of conical shape with high whirling in the tilting pad bearing, is significantly changed by preload and pivot offset regardless of the LBP and LOP configurations. And, the first critical mode, the rigid body mode of conical shape with high whirling in the roller bearing, is sensitively affected by preload applied to the LOP configuration and by its asymmetric dynamic properties.

• 동의신경정신과학회지
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• 제31권2호
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• pp.77-88
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• 2020

Objectives: The study evaluated middle-aged women using the Core Seven Emotions Inventory-short form (CSEI-s) followed by a correlation analysis with Menopause Rating Scale (MRS). Methods: In this study, the medical records of 47 women who visited W University Oriental Medicine Hospital and completed the CSEI-s and MRS were evaluated. A total of 47 women were analyzed using SPSS (Statistical Package for the Social Science, IBM, United States of America, Version 23.0). Frequency analysis, descriptive analysis, independent t-test, one-way ANOVA, Scheffe test, and correlation analysis were conducted. Results: 1. Approximately one-third of all subjects were more than cautious expressing joy and fright. 2. According to their educational status, high-school graduates thought they were superior to those with a bachelor's degree or above. 3. Anger was expressed with caution in the group with severe menopausal symptoms. 4. Anger, thought, depression, sorrow, fear, and fright showed a positive correlation with MRS scores. 5. Among premenopausal and postmenopausal women, fright was associated with menopausal symptoms and response by the autonomous nervous system. Conclusions: The results suggest that CSEI-s can be used to measure the psychological symptoms of middle-aged women.

• 대한전자공학회논문지TC
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• 제42권6호
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• pp.53-60
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• 2005

옥내$\cdot$외의 전력선 환경에 대한 정확한 채널 모델링에 관한 노력이 최근에 이루어지고 있다 알려진 일반 제한과 발표된 모델들은 특별한 형태의 접근들이었다. 본 논문은 더 신속하고 효율적인 전력선 통신 실험을 위한 전력선 채널 특성 측정에 관한 연구이다. 용량성 부하 시뮬레이터는 전력선 옥내 망 모뎀 개발에 필수적인 장비이다. 총 2:H가지 경우의 용량성 부하 변화에 대한 주파수 응답 특성 측정으로 채널 데이터 베이스화를 수행하였다. 본 측정 실험에서 전력선통신 채널은 보다 더 확정적인 매체라는 것을 확인하였다.

• 한국지진공학회논문집
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• 제5권5호
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• pp.35-45
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• 2001

최근에 넓은 공간이 요구되는 건축물에서는 칸막이 벽과 같은 비구조재의 사용이 감소됨으로써 감쇠효과가 크게 줄어들고 있으며 고강도재료의 사용으로 바닥판 구조물이 유연화, 장경간화 되어가고 있다. 대형집회공간, 쇼핑몰, 사무실 등과 같이 장경간 건축물에서는 사람의 움직임에 의하여 과도한 진동이 발생할 수 있으며 이러한 진동은 건축물의 사용성을 크게 저하시키는 원인이 되고 있다. 바닥판 진동의 주요 진동원 중의 하나가 보행하중이다. 보행하중을 받는 구조물의 진동해석에 있어서 보행하중을 적용하는 일반적인 방법은 한 절점에 보행하중을 연속적으로 가하거나 주기하중으로 이상화된 동적하중을 가하는 것이다. 그러나 이러한 방법은 보행의 이동효과를 고려할 수 없다. 본 논문에서는 실제 바닥판 구조물의 고유진동수와 감쇠비를 평가하였으며 예제 구조물의 효율적인 진동해석을 위하여 보행하중을 적용하였다.

• 대한인간공학회지
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• 제29권1호
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• pp.113-120
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• 2010

This research is to evaluate the arousal level by using cardiovascular response. PPG was used in this study as one of the method of measuring it rather than ECG (Electrocardiography) for the purpose of solving ergonomic problem of sensing. The participants were in the age group of 20 (mean=24, standard deviation=1.25): five men and five women. Each experiment composed with four identical sets. First, a black screen was displayed for 30 second rest. Then, the prepared 6 pair images were randomly presented for 10 second stimulation and for 30 second non-stimulation. PPG was measured on the earlobes of experimenters at 200Hz sampling frequency. PPG amplitude, PPI(Pulse to Pulse Interval), and PRV(Pulse Rate Variability) were analyzed according to arousal level. T-test was performed to compare between the PPG variables of rest and relaxation, rest and arousal, and relaxation and arousal. Relative to the rest state, PPG amplitude decreased in relaxed state and increased in aroused state. Relative to the rest state, PPI decreased in both emotional states. However, more significant decline was observed in aroused state. PRV's LF and HF were used in the form of LF/HF to compare between the relaxed and the aroused state. Therefore, PPG signal showed significant differences between relaxed and aroused state. In conclusion, evaluation of human arousal level used in the PPG analysis demonstrated that PPG has better usability and comforter measurement than ECG and is clearly an alternative method of measuring arousal level.

• 한국치위생학회지
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• 제17권1호
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• pp.123-132
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• 2017

Objectives: The purpose of this study was to investigate the current status and contents of communication courses in dental hygiene programs in South Korea. Methods: Survey on dental communication training courses was done, and 51 schools (62.2%) responded among a total of 82 dental hygiene schools in Korea. The questionnaire was sent via e-mail and additional telephone calls were used to facilitate response. Statistical analysis and frequency analysis were done through SPSS 23.0 for windows program (copyright(c) SPSS Inc., USA). Results: The current establishment rates of dental communication courses in 3-year or 4-year dental hygiene programs were 96.9% and 84.2%, respectively. Such courses were identified as graduation requirement courses in 38.7% of the 3-year hygiene programs and 62.5% of the 4-year dental hygiene programs. When practical training sessions are included within such courses, 70% of such courses included 'discussion and presentation' and 'audio-visual aids' as a part of their contents, while 48.3% of them were utilizing 'role-playing'. Conclusions: As dental communication is one of the most important core competencies of dental hygienists, it should be included as a required course for graduation, and practical training such as 'role-playing' should be implemented in order to enhance communication skills in students.

• 한국치위생학회지
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• 제17권1호
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• pp.1-11
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• 2017

Objectives: This study provided students of University with CPR (cardiopulmonary Resuscitation) training and investigated their knowledge on the training, attitude, level difference, and re-training necessity related factors to find the results as follows; Methods: Frequency and t-test was performed using SPSS 21.0, and were conducted according to the need for re-education in order to determine the determinants of the students. Results: The knowledge on CPR was 10.88 on average; training necessity, 3.43; emergency response ability, 3.39; and CPR performance level, 3.10. Factors determining re-training to maintain educational effect were found to increase with increase in school year (p<0.001), training necessity escalation (p<0.001), and decrease in confidence of performing CPR (p<0.01). Conclusions: Based on the findings above, it was found that, although CPR training is generally conducted in dental hygiene education, its training effect decreased with time in terms of implementation performance, compared with students' knowledge. Moreover, students who had completed the training strongly suggested the need for re-training. In this sense, schools will need to reinforce re-training as much as new training programs and the cycle needs to be as short as within 6 months for practical training system.

• 한국소음진동공학회논문집
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• 제23권3호
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• pp.240-248
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• 2013

자동차 수동변속기 내 래틀과 같은 회전체 진동은 엔진 연소폭발 주기와 연동하여 발생한다. 이러한 충격형 진동 특성은 선형 시간 불변 분석법을 적용하여 살펴볼 수 있다. 기어의 동적 특성을 이해하기 위해, 특정 형태의 앞 바퀴 굴림 방식 수동 변속기에 대한 연구를 수행하였다. 첫째, 동특성 고유값과 주파수 응답함수를 기반으로 자유도를 줄이는 방법을 제시하였는데, 이는 행렬의 크기를 줄이는 효과적인 역할을 한다. 둘째, 단일 질량 플라이휠과 이중 질량 플라이휠의 동적 특성을 비교하였다. 모빌리티 분석을 기반으로 한 이중 질량 플라이휠의 효과를 검토하였는데, 이로부터 진동에 의해 가진되는 충격을 회피하기 위한 기본 개념을 이해 할 수 있다. 마지막으로, 두 단계 클러치 댐퍼로부터 유효 강성 값을 도출하여 선형 불변형 시스템 모델을 연구하였다. 두 단계의 서로 다른 클러치 강성조합을 이용하여 클러치 댐퍼의 동적특성에 대한 관계를 예측할 수 있다.

• 대한수의학회지
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• 제34권4호
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• pp.769-779
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• 1994

The root of Bupleurum falcatum L.(BF) has been widely used in oriental medicine as a major camponent in many prescriptions for chronic hepatitis, renal disease, tuberculosis and some other infectious diseases. Many attempts have done to investigate the therapeutic effects of these principles. However, any kinds of screenig on immune regulatory- and antitumor- effects of BF has not been reported. The present study, therefore, was undertaken to investigate the BF-effects on cellular- and humoral-immune responses, phagocytic activities of macrophages, lymphokine- and Immunoglobulin(Ig)-production of lymphocytes, tumorigenesis of implanted sarcoma 180 cells and B16 melanoma cells, and proliferations of some tumor cell lines(Fsa II, 3LL and EL4). BF increased phagocytic activities of mouse peritoneal macrophages in a dose- and time-dependent fashion. Arthus reaction and antibody responses to SRBC were slightly enhanced but delayed hypersensitivity was depresed when BF was injected before- and after-SRBC sensitization. BF inhibited the proliferative responses of human tonsillar lymphocytes to PHA- and Con A-stimulation but slightly augmented the response of these cells to Staphylococcus aureus Cowan 1(SAC)-activation. Ig secretion of human mononuclear cells activated with SAC was slightly increased by BF. BF significantly augmented the SAC-induced IL 6 production of human mononuclear cells but not influenced Con Ainduced IL 2 secretion. NK cell activities of mouse splenocytes were somewhat increased when BF was pretreated and this responses were due to the increment of binding affinities of effector cells to target cells and of lytic activities of effector cells against target cells. In vitro BF significantly inhibited the proliferations of cancer cells such as Fsa II, 3LL and EL4 strains. BF decreased not only the frequency of tumor induction but also the tumor size per sarcoma 180 or B16 cell-implanted mouse. Taken together, these results indicate that BF is one of the potential immunomodulator, and suggest its possibility to be used as a desirable antitumor agent.