• Journal of Astronomy and Space Sciences
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• 제30권2호
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• pp.79-82
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• 2013

We present the Hilbert-Huang transform (HHT) analysis on the quasi-periodic modulation of SMC X-1. SMC X-1, consisting of a neutron star and a massive companion, exhibits superorbital modulation with a period varying between ~40 d and ~65 d. We applied the HHT on the light curve observed by the All-Sky Monitor onboard Rossi X-ray Timing Explorer (RXTE) to obtain the instantaneous frequency of the superorbital modulation of SMC X-1. The resultant Hilbert spectrum is consistent with the dynamic power spectrum while it shows more detailed information in both the time and frequency domains. According to the instantaneous frequency, we found a correlation between the superorbital period and the modulation amplitude. Combining the spectral observation made by the Proportional Counter Array onboard RXTE and the superorbital phase derived in the HHT, we performed a superorbital phase-resolved spectral analysis of SMC X-1. An analysis of the spectral parameters versus the orbital phase for different superorbital states revealed that the diversity of $n_H$ has an orbital dependence. Furthermore, we obtained the variation in the eclipse profiles by folding the All Sky Monitor light curve with orbital period for different superorbital states. A dip feature, similar to the pre-eclipse dip of Her X-1, can be observed only in the superorbital ascending and descending states, while the width is anti-correlated with the X-ray flux.

• 대한치과교정학회지
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• 제23권1호
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• pp.17-35
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• 1993

We tried to evaluate frequencies and severities of malocclusion of various socioeconomic areas according to growth and development. To obtain objective validity, we used Handicapping Labiolingual Deviation (HLD) suggested by Draker, Treatment Priority Index (TPI) by Grainger, Handicapped Malocclusion Assessing Record (HMAR) by American Dental Association and American Association of Orthodontist. Seoul and Kwangju were selected as an urban group, Ahnyang as an middle socioeconomic group and Hwasun near the Kwangju area as an rural group. 140 (male 63, female 73) of 5th grade in 'E' elementary school students in Seoul, 202 (male 101, female 101) of 'S' elementary school students in Kwangju, 207(male 105, female 102) of 'H' elementary school students in Hwasun, and 100(male 49, female 51) of 'M' elementary school students of in Ahnyang of all the same grade were analyzed and we obtained the results as follows; 1. TPI, HLD, and HMAR showed high coincidence and reproducibility between different observer. (p<0.01) 2. In comparison of TPI, HLD, and HMAR according to clinical decision, there was statistically difference between each other. (p<0.01) 3. As the severity of malocclusion increases there was high correlation between TPI and HLD, and between HLD and HMAR (p<0.05) 4. With respect to differences between areas in TPI and HLD, there was statistically difference between Ahnyang and other areas. 5. In Seoul as an urban group there was a high incidence of periodic checkup and history of orthodontic treatment than other area. 6. Mode of feeding and posture during sleeping did not affect the severity of malocclusion. As a conclusion, TPI, HLD and HMAR are so reproducible and coincident that they can be used as a guide on evaluating the frequency and severity of malocclusion and determining the priority of orthodontic treatment to determine the need and supply of orthodontic treatment. Furthermore these indices can provide objectively valid data for establishing public health problem solution.

• 한국전자통신학회논문지
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• 제5권6호
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• pp.637-644
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• 2010

본 연구는 양식장의 수질 환경 인자의 특성을 과학적으로 분석 요약하여 데이터에 의미를 부여하고자 하는 의도와 주기적 교체가 필요한 용존산소 센서에 대한 비용 절감 차원에서 용존 산소 예측을 위한 다중 회귀 모형식을 개발하는데 목적을 두었다. 고흥 거금도에 위치한 두 양식장의 2008.11월~2009.1월 동절기 데이터의 상관성 분석에서 수온은 용존산소와 pH에서는 음의 상관성을 나타냈고 pH는 염도와 용존산소에서 양의 상관성을 나타냈다. 2009년 금호수산 양식장의 수질인자에 대한 월별 통계량 값과 계절별 수질인자 간 차이를 표로 제시하였고 용존산소 예측을 위한 다중회귀 모형식을 개발하여 실제 관측치와 추정치와의 결과를 그래프로 제시하였다. 개발 된 다중 회귀식은 수온이 용존산소에 음의 영향을 주고 pH는 용존산소에 양의 영향을 준다. 또한 수온이 pH에 비해 용존산소 예측에 월등하게 큰 영향을 미치는 걸로 나타났다.

• 천문학회보
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• 제41권2호
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• pp.50.2-50.2
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• 2016

Polarization is a rich source of information on the physical properties of astronomical objects. In particular, scattered sunlight by optically thin media (e.g., cometary comae) shows linear polarization of light, which highly depends on the phase angle (an angle between the Sun-Comet-Earth), wavelengths, and physical properties of cometary dust particles such as size, composition, and structures. Here, we present a study of polarimetric properties of non-periodic comet C/2013 US10 (Catalina) in optical and near-infrared wavelength regions obtained from imaging, spectroscopy, and polarimetric observations taken on UT 2015 December 17 - 19 welcoming its (probably) first close approach to the Earth. In this presentation, we want to introduce our progress since the last Korean Astronomical Society meeting (at BEXCO, Busan, 2016 April 14 - 15) especially in terms of spatial variations of degree of linear polarization (DOLP) and its possible scenarios to explain the correlations with other observational results. In particular, we found that there is strong anti-correlation between the gas/dust flux ratio and DOLP at the cometocentric distance of $(2-5){\times}104 km$. Besides, within 10 arcseconds in radii (corresponding to inner coma region of 104 km from the center), the inverse relationship of these two parameters does not hold anymore. We conjecture that the rapid outward increase of DOLP can be supported by either the sublimation/evaporation of icy volatiles, disaggregation of cometary dust particles ejected from the nucleus, and/or difference of dominant dust particle sizes. From our results, we can conclude that comet C/2013 US10 (Catalina) corroborates rather indefinite traditional classification of poalrimetric classes of comets, and provides good opportunity to study less processed material which probably cherishes its memory at the formation epoch of the Solar System.

• 보건교육건강증진학회지
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• 제7권1호
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• pp.64-71
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• 1990

The purpose of this study is to identify the main factors influencing breast cancer self-examination, a preventive health behavior, thereby increasing self-examination compliance for early detection of the disease. The data on which this study was based were collected from a survey of 601 ladies, aged 20∼59 years and residing in Seoul, employing such mehtods as X²-test, ANOVA, t-test, F-test, Person's Correlation Coefficient and Stepwise Multiple Regression. The resulting conclusions are as follows; 1. Discrepancies in self-examination compliance rate are found in accordance with the differences of general characters of the surveyed persons. For instance, those who are well educated and better off are better compliers than those who are not (p<0.001), and those around whom breast cancer patients are better ones than who are not (p<0.01). 2. Self-examination compliers have higher health belief than non-compliers. Compliers have more knowledge in health and have higher susceptibility, barriers and health concern (p<0.001), and higher benefits (p<0.01), and higher seriousness (p<0.05) than non-compliers. 3. Whereas those who have loftier health belief show higher compliance rate (p<0.001), seriousness turned out to have no correlationship with self-examination compliance. 4. Stepwise Multiple Regression portray that following factors influence self-examination compliance in arder named. (1) barriers (2) susceptibility, (3) health concern, (4) age, (5) benefits, (6) education level. Even so, it turned out that these factors alone can explain only 20％ of self-examination compliance. Therefore study for the other factors ought to be continued. I submit following suggestions ending this study. 1. Since breast cancer self-examination is an essential health behavior needed for early detection of the disease, efficient and proper health education program eyed for regular and periodic self-examination is required to be developed, thus reducing the deaths and pains caused by the disease. 2. Proper policies of the government for the prevention of breast cancer is strongly urged to be formed in concrete manner. 3. Continuous study of the other factors affecting self-examination compliance must be carried on.

• 한국전자파학회논문지
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• 제24권4호
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• pp.410-416
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• 2013

본 논문에서는 통신의 보안성과 수신 성능 향상을 위해서 역지향성 안테나를 이용한 CDSK 변조 방식을 제안한다. 카오스 신호는 신호의 비주기성과 비예측성으로 향상된 보안성을 제공한다. 그러나 카오스 변조 방식은 자기 신호와 간섭 신호로 인해서 수신 성능 열화가 발생한다. 본 논문에서는 카오스 신호 기반 CDSK 변조 방식을 사용하면서도 수신 성능을 유지할 수 있도록 역지향성 안테나를 적용한 카오스 통신 시스템의 성능을 분석한다. 시뮬레이션 결과, 5개의 배열 안테나 소자를 사용하여 역지향성 안테나를 구성할 경우, 제안한 시스템은 향상된 보안성을 제공하며, BPSK 변조를 사용한 통신 시스템과 동일한 수신 성능을 얻는 것을 확인할 수 있다.

• 말소리와 음성과학
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• 제6권3호
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• pp.63-72
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• 2014

The current study assessed the utility of acoustic analyses the most commonly used in routine clinical voice assessment including perturbation, nonlinear dynamic analysis, and Spectral/Cepstrum analysis based on signal typing of dysphonic voices and investigated their applicability of clinical acoustic analysis methods. A total of 70 dysphonic voice samples were classified with signal typing using narrowband spectrogram. Traditional parameters of %jitter, %shimmer, and signal-to-noise ratio were calculated for the signals using TF32 and correlation dimension(D2) of nonlinear dynamic parameter and spectral/cepstral measures including mean CPP, CPP_sd, CPPf0, CPPf0_sd, L/H ratio, and L/H ratio_sd were also calculated with ADSV(Analysis of Dysphonia in Speech and VoiceTM). Auditory perceptual analysis was performed by two blinded speech-language pathologists with GRBAS. The results showed that nearly periodic Type 1 signals were all functional dysphonia and Type 4 signals were comprised of neurogenic and organic voice disorders. Only Type 1 voice signals were reliable for perturbation analysis in this study. Significant signal typing-related differences were found in all acoustic and auditory-perceptual measures. SNR, CPP, L/H ratio values for Type 4 were significantly lower than those of other voice signals and significant higher %jitter, %shimmer were observed in Type 4 voice signals(p<.001). Additionally, with increase of signal type, D2 values significantly increased and more complex and nonlinear patterns were represented. Nevertheless, voice signals with highly noise component associated with breathiness were not able to obtain D2. In particular, CPP, was highly sensitive with voice quality 'G', 'R', 'B' than any other acoustic measures. Thus, Spectral and cepstral analyses may be applied for more severe dysphonic voices such as Type 4 signals and CPP can be more accurate and predictive acoustic marker in measuring voice quality and severity in dysphonia.

• 농촌의학ㆍ지역보건
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• 제16권1호
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• pp.40-47
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• 1991

Musculoskeletal disorders are a major cause of occupational disabilities. Approximately thirty percent state that the major reason for an inability to work is a musculoskeletal problem. A farm work is associated with increased stress and trauma to joints. Chronic overuse injuries are a result of stresses that exceed the body's adaptive or healing capabilities. They can occur in bone, tendons and muscle-tendon-bone junctions. The aim of the investigation was to the study the frequency of pain, ache, and discomfort in the musculoskeletal system among farmers, to find possible correlations between these symptoms and various working positions and different working actions. A questionnaire was answered by 138 farmers. Of those who answered the questionnaire 82% had pain and discomfort from back, shoulders, arms in orders, The result showed that musculoskeletal pain predominate in the farming seasons, and of those who had pain and discomfort 89% thought that farm works had a correlation with the pain and discomfort of musculoskeletal system. But only 17% of quationnaire were put to periodic medical examinations, and 50% of those who had pain and discomfort consulted a doctor. Education in effective pain treatment should therefore be intensifide to ascertain that farmers in rural areas have satisfactory knowledge of the musculoskeletal pain as a chronic overuse syndrome.

• 대한치과의사협회지
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• 제47권9호
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• pp.585-595
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• 2009

Purpose : The aim of this study was to compare surgical complications between simple implant placement and implant placement combined with complicated surgical procedures. We also evaluated prosthetic complications according to the specific types of prosthesis. Material and Method : A retrospective analysis of dental chart of patients who was performed implant therapy during the period from June 2003 to December 2005 was carried out. This study was performed on 408 patients (208 male, 200 female). In addition, 1671 implants were performed. Based on their medical record and radiographs, the authors evaluated surgical and prosthetic complications, surgical procedures accompanied at the time of implant, risk factors of implant failure etc. Result : Surgical complications were developed on 358 implants(21.4% on total placed implants) and wound dehiscence was most prevalent complication. On maxillary posterior area, surgical complications developed more frequently on implants with major surgery and showed a significant difference. And complication rate of implants accompanied with GBR was higher than that of simple implants placement and also showed significant difference. The implant supported prosthesis showed no statistical difference in the occurrence of complications according to the types of prosthesis, and food retention was the most common post-prosthetic complication. Also we speculated that length and width of implant showed significant correlation to the failure of implant primary osseointegration. Conclusion : Based on the result, clinician should provide more careful maintenance for patients with implant placement accompanied by complicated surgical procedure. And periodic maintenance for the patient is requested for long-term survival of implant therapy.

• 한국정보통신학회논문지
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• 제21권10호
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• pp.1973-1980
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• 2017

능동 합성 개구면 소나를 운용하는 소형 수중 무인체는 외부 수중환경의 영향으로 진행경로에 여러 가지 속도 교란이 발생될 수 있으며, 이는 코히어런트 합성 개구면 처리시 위상 오차를 발생시켜 탐지 이미지에 큰 영향을 미친다. 본 연구에서는 진행방향으로 주기적 사인형태의 속도 교란이 발생될 때 각 위치에서 왕복 진행 경사거리에 의해 발생되는 위상을 다중 수신 신호에 대한 상호상관 계수를 추정한 후 중첩된 DPC에서의 위치변위를 최대 허용범위 내에서의 평균값으로 보상하는 방법을 제시하였다. 시뮬레이션을 통하여 수중 무인체의 속도 교란 크기 및 변동 주파수에 의해 손상된 이미지는 제시된 위상 보상 방법으로 허위 표적 제거 및 방위해상도의 성능이 개선됨을 확인하였다.