• Journal of Communications and Networks
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• 제18권3호
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• pp.320-326
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• 2016

In existing literature on multiple-input multiple-output (MIMO) relaying communication systems, antenna selection is often implemented by maximizing the channel capacity or the output single-to-noise ratio (SNR). In this paper, we propose an energy-efficient low-complexity antenna selection scheme for MIMO relaying communication systems. The proposed algorithm is based on beamforming and maximizing the Frobenius norm to jointly optimize the transmit power, number of active antennas, and antenna subsets at the source, relaying and destination. We maximize the energy efficiency between the link of source to relay and the link of relay to destination to obtain the maximum energy efficiency of the system, subject to the SNR constraint. Compared to existing antenna selection methods forMIMO relaying communication systems, simulation results demonstrate that the proposed method can save more power in term of energy efficiency, while having lower computational complexity.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1996년도 하계학술대회 논문집 B
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• pp.859-861
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• 1996

This paper presents the novel fault diagnostic expert system based on dissolved gas analysis(DGA) techniques in power transformer. The uncertainty of key gas analysis, norm threshold, and gas ratio boundaries are managed by using a fuzzy set concept. The uncertainty of rules are handled by fuzzy measures. Trend analysis through the monthly increment of key gas and DGA analysis are combined by the Dempster-Shafer theory, and the state of transformer and confidence factor are yielded by using this combined analysis. To verify the effectiveness of the proposed diagnosis technique, the expert system has been tested by using KEPCO's transformer gas records.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1996년도 추계학술대회 논문집 학회본부
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• pp.143-145
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• 1996

This paper presents the hybrid type based expert system for fault diagnosis in transformers. The proposed system uses the novel fault diagnostic technique based on dissolved gas analysis(DGA) in oil-immersed transformers. The uncertainty of key gas analysis, norm threshold, and gas ratio boundaries are managed by using a fuzzy set. Also, the uncertainty of the fault diagnostic rules are handled by using fuzzy measures. Finally, kohnen's feature map performs fault classification in transformers. To verify the effectiveness of the proposed diagnosis technique, the hybrid type based expert system for fault diagnosis has been tested by using KEPCO's transformer gas records.

• 대한치과교정학회지
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• 제31권5호
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• pp.505-515
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• 2001

대한치과교정학회 부정교합백서 발간위원회에서 보관중인 한국성인 정상교합자의 표본(남 22명, 여 55명)과 연세대학교 치과대학 교정과에서 부정 교합 백서 발간을 위하여 수집한 표본(남자: 21명)을 이용한 한국성인 정상교합자의 치아크기의 계측과 비율에 관한 연구를 통해, 한국성인 정상교합자의 치아크기의 평균치를 구하고, 조화로운 교합관계와 심미성의 획득에 기여하는 치아크기의 비율을 구하여 다음과 같은 결론을 얻었다. 1. 한국성인 정상교합자의 남녀 치아크기의 평균치를 구하였다. 2. 남녀간 치아크기의 평균치 비교에서 상하악 제1대구치를 제외한 치아에서 통계적으로 유의하게 남자의 치아크기가 여자의 치아크기에 비하여 크게 계측되었다(p<0.05). 3. 계측된 한국성인 정상교합자의 치아크기 평균치를 바탕으로 교정치료시 전치부에서의 적절한 수직피개도와 수평피개도, 구치부에서의 적절한 교합관계를 예측할 수 있게 해주는 치아비율을 산출하였다. 1) Sum of incisors = 4 : 2.97 2) Neff anterior coefficient = 1.28 3) Bolton의 anterior ratio = 78.29%, overall ratio = 91.14% 4. 혼합치열기에서 맹출된 4전치 폭경의 합과 상하악 편측 미맹출 견치와 소구치 폭경의 합과의 상관관계를 조사한 결과 양의 상관관계를 나타내었으며, 이 상관관계에 의해 상하악 편측 미맹출 소구치 폭경의 합을 예측할 수 있는 회귀방정식을 구하였다. 1) 미맹출 편측 상악 견치와 소구치 폭경의 합 예측 회귀방정식 = 10.435018 + 0.513346 ${\times}$ (하악 4전치의 합) 2) 미맹출 편측 하악 견치와 소구치 폭경의 합 예측 회귀방정식 = 9.654002 + 0.502565 ${\times}$ (하악 4전치의 합)

• 대한한방내과학회지
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• 제30권3호
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• pp.510-524
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• 2009

Objective : This study was designed to find the correlation between Sasang Constitution and heart rate variability(HRV). Method : There were 665 subjects (280 men and 385 women), between 39 and 72 years old. in a rural community. Sasang Constitution was diagnosed by a Sasang constitutional specialist using PSSC (Phonetic System for Sasang Constitution), face and tongue photo and checkup-list. A structured-questionnaire was used to assess the general characteristics. HRV was recorded using SA-2000 (medi-core). HRV was assessed by time domain and by frequency domain analysis. Metabolic syndrome was defined on the basis of clustering of risk factors, when three or more of the following cardiovascular risk factors were included : blood pressure, fasting blood sugar, triglyceride HDL-cholesterol, and abdominal obesity (waist). Because of the skewness of the data, logarithmic transformation was performed on the absolute units of the spectral components of HRV, and the resulting logarithmic values and normalized units were compared between the groups by a logistic regression. The 95% confidence interval (CI) of the odds ratio was used and calculated from the data laid out for a cross sectional study. Results : 1. Odds ratios of Taeeumin and Soeumin in female adults below 60 years old were significantly lower than that of Soyangin in LF norm and LF/HF ratio. Odds ratios of Taeeumin and Soeumin in female adults below 60 years old were significantly higher than that of Soyangin in HF norm. 2. There was no significant correlation between HRV and Sasang Constitution in female adults from 60 years old and over. 3. There was no significant correlation between HRV and Sasang Constitution in male adults. Conclusion : There is a statistically significant correlation between the HRV and Sasang Constitution. There is a tendency of increase in the sympathetic activity in Soyangin. There is a tendency of decrease in the parasympathetic activity in Taeeumin and Soeumin.

• 대한소아치과학회지
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• 제32권1호
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• pp.109-118
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• 2005

소아치과 영역에서 아동의 두부방사선 계측치의 비교분석은 성장과 발육의 평가에 중요하며 부정교합의 조기진단과 치료를 위한 두개 안면부의 형태, 성장 양상을 아는 것에 필수적이다. 이를 위하여 두부방사선 계측학적 표준치가 중요한데 유치열기에 관한 연구는 많지 않으므로 유치열기 정상교합 아동의 표준치를 얻고 과거 연구에서의 계측치와 비교하고자 서울시내 소재의 유아원 아동 중 유치열기의 정상교합을 가진 4세에서 5세 아동으로 본원에 내원한 안모 및 전신 발육 상태가 양호한 아동 46명을 대상으로 측모 두부방사선 계측 사진을 촬영, 분석하여 다음과 같은 결과를 얻었다. 1. 골격성 계측항목에서 각도 계측치는 남녀사이에 유의한 차이가 없고 길이 계측치는 남자가 여자보다 전반적으로 큰 수치를 보였다. 2. SNA는 $81.3^{\circ}$, SNB는 $76.6^{\circ}$, ANB difference는 $4.7^{\circ}$를 나타냈다. 3. Anterior cranial base length에 대한 Mandibular body length의 비율은 남녀모두 0.9:1이었고 Anterior facial height에 대한 Posterior facial height의 백분율은 남자 61.4%, 여자 62.0%를 나타냈다. 4. 치성 계측항목에서는 IMPA는 $84.2^{\circ}$, UA to SN은 $90.8^{\circ}$를 나타냈다. 5. Ricketts의 심미선에 대하여 상순은 2.6mm, 하순은 2.5mm 전방으로 위치하고 있었다.

• 동의신경정신과학회지
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• 제21권4호
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• pp.163-173
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• 2010

Objectives : The objective of this study was to assess the effects of acupuncture applied at 114 and Liv3 points on heart rate variability (HRV) in normal subjects under mental stress. Methods: 36 healthy male and female subjects were recruited and randomized to a treatment group(18 subjects) or a control group (18 subjects). After 10-minutes rest period and instrumentation, both groups performed a mental stress test(Stroop color word test, Arithmetic test. four rule of arithmetic task) for l6-minutes. HRV was recorded before and after the mental stress. And then acupuncture needles were inserted on 114 and Liv3 for the study group. In the control group, they rested for l5-minutes. And Heart rate variability(HRV) was measured. Results: In the both groups, low frequency(LF) power, normalized low frequency power(LF(norm)) and ratio of low frequency to high frequency(LF/HF) was significantly increased after mental stress. Acupuncture induced significant decrease in low frequency(LF) power, normalized low frequency power(LF(norm)) and ratio of low frequency to high frequency (LF/HF) which was increased after mental stress test. In contrast, control group induced no changes. Conclusions : Acupuncture on 114 and Liv3 could be useful to decrease sympathetic activity and prevent the alteration of autonomic nervous system due to mental stress.

• 척추신경추나의학회지
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• 제7권2호
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• pp.39-52
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• 2012

Objectives : The purpose of this study was to investigate the correlation between lumbar lordotic angle and the power of trunk flexors, extensors in normal adults Methods : 34 normal participants participated in this study. Their lumbar lordotic angle(L1-S1 Cobb's angle and L1-L5 cobb's angle) was measured by x-ray taken on lateral direction, erect cross-arm position. And muscle power of trunk flexors and extensors of each participant measured using Cybex HUMAC NORM. Results : 1. The average of L1-S1 Cobb's angle was $47.21{\pm}8.88^{\circ}$ and the average of L1-L5 Cobb's angle was $36.32{\pm}9.62^{\circ}$(Table IV). 2. The average ratio of trunk flexors/extensors was $6.44{\pm}19.31%$(Table V). The average power of the trunk flexors was $165.18{\pm}55.05$(Newton-Meter/kg), and the power of trunk extensors was $257.18{\pm}85.53$ (Newton-Meter/kg)(Table VI). 3. Lumbar lordotic angle has no relation to the ratio of trunk flexors/extensors(Table VII, Fig. 4). 4. Lumbar lordotic angle has no relation to both the power of the trunk flexors and extensors(Table VIII, Fig. 5, Fig. 6). Conclusions : These results suggest that the lumbar lordotic angle measured by radiograph could not evaluate the power and ratio of trunk flexors, extensors.

• Earthquakes and Structures
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• 제27권1호
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• pp.1-15
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• 2024

In order to enhance the seismic performance of base-isolated structures on soft foundations, the hybrid system of base-isolated system (BIS) and shape memory alloy inerter (SMAI), referred to as BIS+SMAI, is for the first time here proposed. Considering the nonlinear hysteretic relationships of both the isolation layer and SMA, and soil-structure interaction (SSI), the equivalent linearized state space equation is established of the structure-BIS+SMAI system. The displacement variance based on the H₂ norm is then formulated for the structure with BIS+SMAI. Employing the particle swarm optimization, the optimization design methodology of BIS+SMAI is presented in the frequency domain. The evolvement rules of BIS+SMAI in the effectiveness, robustness, SMA driving force, inertia force, stroke, and damping enhancement effect are revealed in the frequency domain through changing the inerter-mass ratio, structural height, aspect ratio, and relative stiffness ratio between the soil and structure. Meanwhile, the validation of BIS+SMAI is conducted using real earthquake records. Results demonstrate that BIS+SMAI can effectively reduce the isolation layer displacement. The inerter can significantly increase the hysteretic displacement of SMA and thus enhance its energy dissipation capacity, implying that BIS+SMAI has better effectiveness than BIS+SMA. Although BIS+SMAI and BIS+ tuned inerter damper (TID) have practically the same effectiveness, BIS+SMAI has the lower optimum damping, significantly smaller inertia force, and higher robustness to perturbations of the optimum parameters. Therefore, BIS+SMAI can be used as a more engineering realizable hybrid system for enhancing the performance of base-isolated structures in soft soil areas.

• 생명과학회지
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• 제12권6호
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• pp.780-785
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• 2002

본 연구는 고교 레슬링선수들의 단기간 체중감량에 따른 등속성 운동능력 중 다리의 peak torque, peak torque %BW, total work, total work %BW, endurance ratio에 대한 변화를 알아보기 위하여 자기 체중에서 체중감량이 없는 집단 7명, 5%이상 감량집단 7명을 대상으로 체중감량 전ㆍ후를 측정하여 얻은 결론은 다음과 같다. 1. Peak Torque의 변화. 굴근의 경우 5%이상 감량 집단의 $60^{\circ}C$sec, $90^{\circ}C$/sec에서 유의하게 감소하였다. 그리고 신근의 경우 5%이상 감량 집단의 $60^{\circ}C$/sec, $90^{\circ}C$/sec, $250^{\circ}C$/sec에서 모두 유의하게 감소하였다. 2. Peak Torque %BW의 변화. 굴근의 경우 5%이상 감량 집단의 60$^{\circ}$/sec, 90$^{\circ}$/sec, $150^{\circ}C$/sec에서 모두 유의하게 감소하였다. 그리고 신근의 경우 5%이상 감량 집단의 $90^{\circ}C$/sec와 $250^{\circ}C$/sec에서 유의하게 감소하였다. 3. Total Work의 변화. 굴근의 경우 5%이상 감량 집단의 $60^{\circ}C$/sec,$90^{\circ}C$/sec에서 유의하게 감소하였다. 그리고 신근의 경우 5%이상 감량집단의 $50^{\circ}C$/sec, $90^{\circ}C$/sec. $250^{\circ}C$/sec에서 모두 유의하게 감소하였다. 4. Total work %BW의 변화. 굴근의 경우 5%이상 감량 집단의 $60^{\circ}C$/sec, $90^{\circ}C$/sec, $250^{\circ}C$/sec에서 유의하게 감소하였다. 그리고 신근의 경우 5%이상 감량 집단의 $50^{\circ}C$/sec, $90^{\circ}C$/sec, $250^{\circ}C$/sec에서 모두 유의하게 감소하였다. 5. Endurance Ratio의 변화. 굴근과 신근의 경우 두 집단 모두 유의한 차이가 없었다. 단기간의 무리한 체중감량은 근력, 근지구력의 저하로 경기력을 저하시킬 뿐만 아니라 건강을 해칠 우려가 있기 때문에 단기간의 무리한 감량이 되지 않도록 과학적이고 체계적인 체중관리가 이루어져야 할 것으로 사료된다.