• 한국군사과학기술학회지
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• 제15권6호
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• pp.812-819
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• 2012

Interference and jamming are becoming increasing concern to a radar system nowdays. AESA(Active Electronically Steered Array) antennas and adaptive beamforming(ABF), in which antenna beam patterns can be modified to reject the interference, offer a potential solution to overcome the problems encountered. In this paper, we've developed a planar active phased array radar system, in which ABF, target detection and tracking algorithm operate in real-time. For the high output power and the low noise figure of the antenna, we've designed the S-band TRMs based on GaN HEMT. For real-time processing, we've used wavelenth division multiplexing technique on fiber optic communication which enables rapid data communication between the antenna and the signal processor. Also, we've implemented the HW and SW architecture of Real-time Signal Processor(RSP) for adaptive beamforming that uses SMI(Sample Matrix Inversion) technique based on MVDR(Minimum Variance Distortionless Response). The performance of this radar system has been verified by near-field and far-field tests.

• 한국항행학회논문지
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• 제17권6호
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• pp.638-645
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• 2013

유한한 주파수 자원을 효율적으로 이용하기 위해서는 무선국 설계시 지역별 전파환경에 기반한 전파전달 특성을 정확히 예측하여 무선국의 송신출력 및 서비스 커버리지 등을 설계하는 것이 필요하다. 따라서 세계 각국에서는 자국의 환경에 맞는 전파모델을 확보하려고 노력하고 있으며, 국내에서도 BCAST와 같은 모델이 개발되어 전파분석에 이용되어 왔지만, 아직도 측정결과와 상이한 결과를 제공하고 있다. 이에 본 연구에서는 국내 Rural 지역의 DTV 방송서비스에 대해 측정한 후, 측정된 데이터와 SMIS 예측모델 P.1546 및 BCAST에 대한 실측/예측 비교분석 및 이의 오차 분석을 수행하여 SMIS 향후 개선방안을 제시한다. ITU-R 권고안 P.1546 및 BCAST 모델적용에 있어 실측/예측 오차, 특히 BCAST 모델인 경우 측정치 보다 높게 예측되는 문제점 등이 도출되어, 향후 숲과 나무에 의한 페이딩, 호수 및 바다에 의한 전파반사 등에 대한 정밀한 분석이 필요하다.

• 한국항행학회논문지
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• 제17권5호
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• pp.484-490
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• 2013

VHF 및 UHF 대역에서 무선통신의 급격한 발전에 따라 신뢰할 만한 전파예측 기법에 대한 요구가 증가하고 있다. 따라서 국내뿐만 아니라 세계 각국에서는 자국의 환경에 맞는 전파모델을 확보하려고 노력하고 있고, 많은 모델이 개발되어 전파분석에 이용되어 왔지만, 아직도 측정결과와 상이한 결과를 제공하고 있다. 이에 본 연구에서는 국내 대도심지역의 DTV 방송서비스 방송 주파수에 대해 측정한 후, 측정된 데이터와 전파자원분석시스템(SMIS)내의 예측모델 P.1546 및 BCAST에 대한 실측/예측 비교분석 및 이의 오차 분석을 수행하여 SMIS 향후 개선방안을 제시한다. P.1546 및 BCAST 모델적용에 있어 실측/예측 오차, 특히 BCAST 모델인 경우 상하로 큰 오차를 보이는 문제점 등이 도출되어 고층건물에 의한 회절손실 등에 대한 면밀한 분석이 향후 필요하다.

• Nutrition Research and Practice
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• 제9권5호
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• pp.503-510
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• 2015

BACKGROUND/OBJECTIVES: Increased serum homocysteine (Hcy) levels have been reported to be related to the occurrence of cardio- and cerebrovascular diseases. High serum Hcy levels are also related to the development of secondary stroke and all-cause mortality. The purpose of this study was to investigate the prevalence of high serum homocysteine level and relating factors, and the change over the 10 month period post-stroke. SUBJECTS/METHODS: Consecutive stroke patients who were admitted to the Asan Medical Center were enrolled. Ten months after the onset of stroke, an interview with a structured questionnaire was performed and blood samples were obtained for the biochemical parameters. Nutritional status was determined using the mini nutritional assessment (MNA) score and dietary nutrient intakes were also obtained using a 24 hour recall method. RESULTS: Out of 203 patients, 84% were malnourished or at risk of malnutrition, and 26% had high homocysteine levels at 10 months post-stroke. Using logistic regression, the factors related with high homocysteine levels at 10 months post-stroke included heavy alcohol consumption (P = 0.020), low MNA scores (P = 0.026), low serum vitamin $B_{12}$ (P = 0.021) and low serum folate levels (P = 0.003). Of the 156 patients who had normal homocysteine levels at admission, 36 patients developed hyperhomocysteinemia 10 months post-stroke, which was related to heavy alcohol consumption (P = 0.013). Persistent hyperhomocysteinemia, observed in 22 patients (11%), was related to male sex (P = 0.031), old age (P = 0.042), low vitamin $B_6$ intake (P = 0.029), and heavy alcohol consumption (P = 0.013). CONCLUSION: Hyperhomocysteinemia is common in post-stroke, and is related to malnutrition, heavy alcohol drinking and low serum level of folate and vitamin $B_{12}$. Strategies to prevent or manage high homocysteine levels should consider these factors.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2016년도 학술발표회
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• pp.605-605
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• 2016

최근 기후변화로 인한 국지적 또는 대규모 극한 가뭄과 홍수가 빈발함에 따라 수자원 관리 여건은 점점 더 어려워지고 있다. 이런 물 관련 재해에 보다 효과적으로 대응하기 위해서는 수자원인자에 대한 시공간적 모니터링이 필수적인데, 이러한 관점에서 시공간적 광역관측이 가능한 위성자료의 활용가치는 매우 높게 평가되고 있으며, 최근에는 국내외적으로 위성자료를 이용하여 수문 인자 산출, 가뭄 홍수 등의 모니터링 기술 등에 대한 연구가 활발히 진행되고 있다. K-water는 위성정보 활용기술력 축적을 통한 보다 효율적인 수자원 관리를 하기 위하여 수자원 분야에 활용 가능한 해외의 주요 위성자료를 실시간 직수신 처리하여 표출하는 K-water 위성영상관리시스템(K-SIMS, K-water Satellite Image Management System)을 2015년에 구축하였다. 현재 K-SIMS를 통해 관리되는 위성은 AQUA, TERRA, NPP, GCOM-W, GPM로서 총 5개이다. AQUA, TERRA, NPP 위성은 각 궤도운영 스케쥴에 따라 한반도 상공을 통과하는 시각에 안테나가 위성의 궤도를 따라가며 수신하고, GCOM-W, GPM 위성자료는 FTP 접속를 통해 준실시간으로 수신하고 있다. 산출물은 AQUA, TERRA, NPP가 각각 23종, GCOM-W 9종, GPM 2종 등 총 80여종으로 위성원시자료 수신즉시 처리 표출까지 실시간 자동 수행되고 있으나 식생지수, 강수, 구름, 대기온도, 수증기 등 대부분 수문기상학적 변수들로 구성되어 있어 수자원 관리 현업 업무에는 직접 사용하기에는 다소 한계가 있다. 따라서, 위성자료의 활용성을 높이기 위하여 수문해석에 중요한 변수인 토양수분에 대해서 AQUA, TERRA의 MODIS LST(Land Surface Temperature)와 식생지수(Vegetation Index)를 이용하여 SMI(Soil Moisture Index)를 산출하고 이를 K-SIMS에 표출하는 체계를 추가로 구축하여 현업 활용도가 높은 자료를 생산하고 있으며, 향후 위성자료를 활용한 가뭄지수를 추가로 산출하여 표출할 계획이다. 이와 함께 K-water는 차세대 중형위성 개발 사업에 따른 수자원 위성 확보에 대비해 수자원 분야 위성활용 중장기 계획을 마련하였다. 향후에 광학위성, SAR위성 등 다양한 위성자료의 융복합적 활용을 통하여 위성산출물 알고리즘을 지속적으로 개발함으로써 홍수, 가뭄, 수질 등 물 재해 대응 및 수자원 관리 전 분야에 위성자료의 활용을 확대해 나갈 계획이다.

• Perspectives in Nursing Science
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• 제8권1호
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• pp.62-72
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• 2011

Purpose: The purpose of this study was to investigate QOL and the factors related to family caregivers who care for Amyotrophic Lateral Sclerosis (ALS) patients. Methods: The subjects were 83 family caregivers caring for ALS patients who visited the neurology outpatient section of a tertiary hospital located in Seoul between January and July of 2008. Their demographic characteristics were assessed and data were collected using the amyotrophic lateral sclerosis functional rating scale (ALSFRS), the caregiver burden inventory (CBI), HADS, and SF-36. Results: The mean score of the physical health component (PHC) of the family caregiver's QOL was $62.6{\pm}24.4$, and the mean score of the mental health component (MHC) of their QOL was $57.7{\pm}22.4$. The mean score of caregiver burden was $76.5{\pm}30.7$. Anxious family caregivers amounted to 55.4% and depressed family caregivers accounted for 63.9% overall. In a multivariate analysis, the PHC of QOL was explained by caregiver burden (41.1%), depression (9.4%), caregiver gender (3.8%), and caregiver age (3.1%). Anxiety (39.8%), caregiver burden (10.9%), patient gender (5.4%) and depression (1.7%) were predictive factors of the MHC of QOL. Conclusion: Caregiver burden and depression affected both the PHC and the MHC. Caregiver burden affected the PHC more than it did the MHC of QOL, but anxiety affected the MHC more than it did the PHC of QOL.

• PNF and Movement
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• 제13권1호
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• pp.31-37
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• 2015

Purpose: The purpose of this study is to compare changes in the flexibility of hamstring muscles which are relaxed on suboccipital muscle through suboccipital muscle inhibition and combination technique. Methods: Thirty sample subjects (16 male and 14 female) were randomly divided into an experimental group (n=15) and a control group (n=15). 1. Suboccipital muscle inhibition: Suboccipital muscles of the patients were placed on a bed. The occipital region was placed on a therapist's fingers, and the posture was maintained for three minutes before remeasurement. 2. Treatment with combination technique (body bolster and wooden pillow): Wooden pillows were placed where the participants could relax the posterior arch of the atlas; additional body bolsters were also placed to avoid high pressure, and the treatment was maintained for three minutes before remeasurement. Results: There was a statistical difference in finger floor distance (FFD) and straight leg raise (SLR) results for those treated with SMI (P<0.05). There was no statistical difference in FFD and SLR results for those treated with the combination technique (P>0.05). Conclusion: Between the two intervention methods; the suboccipital muscle inhibition technique was more effective in increasing the flexibility of subjects with a shortened hamstring than was the combination technique.

• 산업경영시스템학회지
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• 제44권3호
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• pp.50-63
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• 2021

There has been a steady rate of accident in Coal Thermal Power Plants which have relatively higher chance of mortality. However, neither the systematic view of safety management nor the methodology such as safety factors or system requirements are yet to be studied in detail. Therefore, this study aims to propose a methodology to preemptively deal with safety issues and to secure fact focused responsibility in safety. It consists of two main parts. First, the Safety Measurement Index(SMI) with total 50 factors is proposed by analyzing the key factors that contribute to safety accidents based on failure mode and effect analysis (FMEA) and quality function deployment (QFD). To analyze the safety requirements, index presented by major countries and organizations are discussed. Second, main features of intelligent CCTV are studied to determine their relative importance for the framework of Smart Safety Management System (SSMS). Main features are discussed with four technological steps. Also, QFD was held to analyze to analyze how key technologies deal with Quality Measurement Index(QMI). The research results of this study reveal that scientific approaches could be utilized in integrating CCTV technologies into a smart safety management system in the era of Industry 4.0. Moreover, this reasearch provides an specific approach or methodology for dealing with safety management in Coal Thermal Power Plant.

• 한국전자통신학회논문지
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• 제16권2호
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• pp.247-254
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• 2021

무선기술 및 통신 서비스의 급속한 발전에 따라 주파수 자원의 부족과 인접 대역 전파 간섭 등의 문제가 지속적으로 제기되고 있다. 해결방안으로 정부에서는 주파수자원분석시스템(Spectrum Management Intelligent System, SMIS)을 운영 중이다. 본 논문은 주파수자원분석시스템의 신뢰성을 검증하기 위하여, SMIS 시뮬레이션 값을 상용툴 ATDI 결과값 및 ITU-R Matlab 코드 결과값과 비교하였다. 전파 모델 중 방송망과 연관이 있는 권고서 ITU-R P.526, P.1546, P.1812를 선정하였다. 분석 결과, SMIS의 추출값은 전체적으로 1dB이내의 작은 오차를 갖는다. 본 연구는 향후 주파수 분배와 인접 대역간 간섭분석 정책 수립과 연구 개발 등에 활용될 수 있을 것으로 예상한다.

• Journal of Korean Biological Nursing Science
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• 제21권3호
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• pp.188-198
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• 2019

Purpose: The purpose of this study was to examine the effect of laughter therapy on depression, anxiety, fatigue, and quality of sleep in gastrointestinal cancer survivors. Methods: This study was a randomized controlled trial. We compared the effect of laughter therapy with usual care only in post chemotherapy gastrointestinal patients. Outcomes included changes in depression and anxiety (according to the Hospital Anxiety and Depression Scale), fatigue (according to the Fatigue Severity Scale), and quality of sleep (according to the Verran & Synder-Halpern Sleep Scale). Data was collected July 2015 through January 2016. Seventy nine participants who agreed to participate in this study were randomized to either the experimental group (n= 40) or the control group (n= 39). Therapy included eight sessions (60 minutes each, once weekly). Data were analyzed using the Windows SPSS 22.0 program. Results: Laughter therapy was effective in reducing fatigue (p= .019) and increasing satisfaction of sleep (p= .030). There were no differences between the groups after therapy for depression (p= .129) and anxiety (p= .200). Conclusion: Results of this study indicate that laughter therapy may be an effective nursing intervention for improving the health status of gastrointestinal cancer survivors after chemotherapy.