• 한국위성정보통신학회논문지
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• 제4권2호
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• pp.5-11
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• 2009

본 논문에서는 무선 인지 시스템 사용자의 전송 품질을 향상시킬 수 있는 위성을 이용한 무선 인지 시스템의 무선 자원 할당 방법을 제안한다. 무선 인지 시스템은 주파수 사용의 효율성을 높이기 위해 제안된 시스템이다. 무선 인지 시스템은 주사용자의 성능에 영향을 미치지 않도록 동작하여야 하기 때문에 무선 인지 시스템 사용자의 상황에 따라서 전송 품질을 보장할 수 없는 경우가 생긴다. 특히, 무선 인지 시스템의 사용자가 늘어날수록 주사용자에게 미치는 간섭 외에도 무선 인지 사용자간의 간섭 또한 증가하기 때문에 시스템 성능이 저하 될 수 있다. 이런 문제를 해결하기 위해 무선 인지 시스템과 위성을 이용한 적응적인 자원 할당 기법을 제안한다. 이 방법을 통해 무선 인지 시스템의 성능을 향상 시킬 수 있다.

• 한국인터넷방송통신학회논문지
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• 제11권3호
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• pp.17-22
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• 2011

본 논문에서는 멀티 홉 군통신 시스템에서 발생할 수 있는 동일채널 간섭 (CCI : Co-Channel Interference) 제거 성능을 분석하였다. 간섭 제거 기법으로 먼저 Zero Forcing (ZF)과 Minimum Mean Square Error (MMSE) 기법을 적용하여 간섭을 제거한 후, 연속 간섭 제거 (SIC : Successive Interference Cancellation) 알고리즘을 이용하여 추가적인 다이버시티 이득을 얻고 간섭 제거 성능을 향상시킨다. 무선 채널은 레일레이 (Rayleigh) 페이딩 채널을 고려하여 모의 실험을 하였으며, 시스템 성능은 비트 오류 확률 (Bit Error Probability) 측면에서 분석되었다. 모의실험 결과로부터, 멀티 홉 무선 네트워크 환경에서 MMSE가 ZF보다 BER 성능을 현저하게 향상시킴을 확인하였으며, 각각 기법에 연속 간섭 제거 알고리즘을 적용한 경우, 그 성능이 더욱 좋아지는 것을 알 수 있었다. 따라서 MMSE-SIC 방식은 멀티 홉 군통신 시스템에서 보다 신뢰성 있는 신호의 전송을 제공할 수 있다.

• Environmental Analysis Health and Toxicology
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• 제25권1호
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• pp.57-68
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• 2010

This study assessed the lifetime cancer and non-cancer risk of aldehydes and volatile organic compounds exposure of young children at child-care facilities and indoor playgrounds in Korea. The samples were collected at various children's facilities (40 day-care houses, 42 child-care centers, 44 kindergartens, and 42 indoor playgrounds) in summer (Jul~Sep, 2007), winter (Jan~Feb, 2008) and Spring (Mar~Apr, 2008) periods, and analyzed by GC-MS. We estimated the lifetime excess cancer risks (ECRs) of formaldehyde, acetaldehyde, benzene, chloroform, CCI4 and tetrachloroethylene, and the hazard quotients (HQs) of Non-carcinogens (toluene, xylene, benzaldehyde and formaldehyde). Formaldehyde evaluated both cancer and non-cancer risk. The average ECRs of formaldehyde for young children were $1\times10^{-4}{\sim}1\times10^{-5}$ level in all facilities. HQs of four non-carcinogens did not exceed 1.0 for all subjects in all facilities.

• 한국산학기술학회논문지
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• 제13권6호
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• pp.2672-2679
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• 2012

본 연구는 급성심근경색증 환자의 사망률 측정을 위한 중증도 보정 모형을 개발하여 의료의 질 평가에 필요한 기초자료를 제공하고자 수행되었다. 이를 위해서 질병관리본부의 2005-2008년 퇴원손상환자 699,701건의 자료를 분석하였다. Charlson Comorbidity Index 보정 방법을 이용한 경우와 새롭게 개발된 중증도 보정 모형의 예측력 및 적합도를 비교하기 위해 로지스틱 회귀분석을 실시하였다. 새롭게 개발된 모형에는 연령, 성, 입원경로, PCI 유무, CABG 유무, 동반질환 12가지 변수가 포함되었다. 분석결과 CCI를 이용한 중증도 보정 모형보다 새롭게 개발된 중증도 보정 사망 모형의 C 통계량 값이 0.796(95%CI=0.771-0.821)으로 더 높아 모형의 예측력이 더 우수한 것으로 나타났다. 본 연구를 통하여 중증도 보정 방법에 따라 사망률, 유병률, 예측력에도 차이가 있음을 확인하였다. 향후에 이모형은 의료의 질 평가에 이용하고, 질환별로 임상적 의미와 특성, 모형의 통계적 적합성 등을 고려한 중증도 보정모형이 계속해서 개발되어야 할 것이다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제11권7호
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• pp.3501-3523
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• 2017

It is a classical integer optimization difficulty to design an optimal selection scheme in cooperative relay networks considering co-channel interference (CCI). In this paper, we solve single-objective and multi-objective relay selection problem. For the single-objective relay selection problem, in order to attain optimal system performance of cooperative relay network, a novel quantum differential evolutionary algorithm (QDEA) is proposed to resolve the optimization difficulty of optimal relay selection, and the proposed optimal relay selection scheme is called as optimal relay selection based on quantum differential evolutionary algorithm (QDEA). The proposed QDEA combines the advantages of quantum computing theory and differential evolutionary algorithm (DEA) to improve exploring and exploiting potency of DEA. So QDEA has the capability to find the optimal relay selection scheme in cooperative relay networks. For the multi-objective relay selection problem, we propose a novel non-dominated sorting quantum differential evolutionary algorithm (NSQDEA) to solve the relay selection problem which considers two objectives. Simulation results indicate that the proposed relay selection scheme based on QDEA is superior to other intelligent relay selection schemes based on differential evolutionary algorithm, artificial bee colony optimization and quantum bee colony optimization in terms of convergence speed and accuracy for the single-objective relay selection problem. Meanwhile, the simulation results also show that the proposed relay selection scheme based on NSQDEA has a good performance on multi-objective relay selection.

• 한국임상약학회지
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• 제26권2호
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• pp.128-136
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• 2016

Objective: This study was to explore the association between having a usual source of care and adherence to medicines in patient with chronic diseases. Methods: The 2012 Korea Health Panel was used as a data source. We analyzed 4,418 respondents that were diagnosed with chronic diseases and utilized health care services. Non-adherence to medication, a dependent variable, was defined as "not taking the medicines that were prescribed for treating chronic disease" or "not following the direction for medication". Whether having a usual source of care or not was used as a key independent variable, which was defined as having a regular site or a regular doctor for medical test, treatment, and consultation. Sex, age, education level, marital status, income, the type of health insurance, the number of chronic disease and CCI (Charlson Comorbidity Index) were included as covariates in the analysis. We conducted a multivariate logistic regression. Results: Totally, 30 percent of respondents reported to experience non-adherence to medication. Having a usual source of care was significantly associated with lower non-adherence to medication regardless its type, which is a regular doctor (OR=0.61, 95% CI=0.53-0.70) or a regular site (OR=0.67, 95% CI=0.58-0.78). Furthermore, having a usual source of care was associated with both of medication persistence (OR=0.66, 95% CI=0.54-0.81) and compliance (OR=0.65, 95% CI=0.56-0.76). Conclusion: Our results showed the possibility that usual source of care is able to conduct a positive role in improving adherence to medication with better management of chronic disease.

• 대한원격탐사학회지
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• 제36권4호
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• pp.587-607
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• 2020

Soil moisture is essential information for meteorological and hydrological analyses. To date, many efforts have been made to achieve the two goals for soil moisture data, i.e., the improvement of accuracy and resolution, which is very challenging. We presented an ensemble downscaling method for quality improvement of gridded soil moisture data in terms of the accuracy and the spatial resolution by the integration of BMA (Bayesian model averaging) and ATPRK (area-to-point regression kriging). In the experiments, the BMA ensemble showed a 22% better accuracy than the data sets from ESA CCI (European Space Agency-Climate Change Initiative), ERA5 (ECMWF Reanalysis 5), and GLDAS (Global Land Data Assimilation System) in terms of RMSE (root mean square error). Also, the ATPRK downscaling could enhance the spatial resolution from 0.25° to 0.05° while preserving the improved accuracy and the spatial pattern of the BMA ensemble, without under- or over-estimation. The quality-improved data sets can contribute to a variety of local and regional applications related to soil moisture, such as agriculture, forest, hydrology, and meteorology. Because the ensemble downscaling method can be applied to the other land surface variables such as temperature, humidity, precipitation, and evapotranspiration, it can be a viable option to complement the accuracy and the spatial resolution of satellite images and numerical models.

• 한국경제지리학회지
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• 제15권2호
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• pp.258-273
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• 2012

본 연구는 기업 사회공헌활동을 지역사회 참여수준에 따라 적극적 지역사회공헌활동과 소극적 지역사회공헌활동으로 분류하여, 지역사회 참여수준에 따른 기업 사회공헌활동의 지역사회발전 효과성을 지역주민을 중심으로 분석하였다. 국내기업의 사회공헌활동 우수사례를 지역사회 참여수준에 따라 정리하여 선정하였으며, 선정된 활동들을 대상으로 경제성, 안전성, 편리성, 쾌적성, 사회 문화성의 5개 요인을 조사하여 지역사회발전 효과성을 분석하였다. 분석결과, 지역사회 참여수준이 높은 적극적인 지역사회공헌활동의 경우, 지역사회발전 효과성이 5개 지역사회발전 요인 모두에서 높게 나타났다. 따라서 기업 사회공헌활동의 지속적인 발전을 위해서는 보다 적극적으로 지역사회와 소통하고 다양한 네트워크를 구축해나갈 필요가 있다. 이에 향후 효율적인 커뮤니케이션을 위해 역할을 조정하고 유연하게 대응해줄 중간매개기관의 중요성이 높아질 것으로 판단된다.

• 한국수의병리학회지
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• 제5권1호
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• pp.9-16
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• 2001

To investigate the effects of safflower seed supplementation diet on the hepatic injury of rats administered with carbon tetrachloride (CCI$_4$), histopathological changes were assessed following acute and chronic administration in rats. In acute cases, all rats in group fed with 10% safflower seed supplementation diet survived despite the administration of lethal doses of $CCl_4$. However, most rats in group fed with control diet died. The hepatic injuries of survived rats, in the histopathological findings, were mild compared to those of dead rats. In the chronic cases, livers of group 2 fed with control diet were more progressive in fatty changes and centrilobular necrosis than those of group 3 fed with 20%safflower seed diet. However, after six weeks, livers of group 2 and 3 showed severe necrosis and mild fibrosis at the same time. Group 5 fed with 10% safflower seed supplementation diet and water containing 0.05% phenobarbital sodium showed mild fatty changes and necrosis compared with group 4 fed with control diet and water containing 0.05% phenobarbital sodium at sixth week. At 8 to 10 wee71s after the administration of $CCl_4$, severe fibrosis. fatty changes and marked necrosis were observed in group 4, but hepatic injuries were less severe in group 5. The present results suggested that safflower seed has some protective effect in hepatic lesions and consequently delay the progression of hepatic fibrosis.

• 한국병원경영학회지
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• 제22권4호
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• pp.113-122
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• 2017

The purpose of the study was to investigate the patient, disease and hospital characteristics which affect treatment result and early complication for inpatients with psychiatric comorbidity. We analyzed data on 19,806 patients of the Korea Centers for Disease Control and Prevention from 2012 to 2014, Korea National Hospital discharge in-depth data. Frequency, chi-square and logistic regression analysis was performed, using STATA 12.0. According to logistic regression analysis, gender(Odds ratio(OR)=0.776, 95% confidence interval(CI)=0.686-0.878), insurance type(OR=0.853, CI=0.731-0.995), operation(OR=0.424, CI=0.350-0.513), disposition(OR= 39.307, CI=34.394-44.923), beds(300-499, OR=0.470, CI=0.377-0.585; 500-999, OR=0.462, CI=0.395-0.541; 1000 over, OR=0.598, CI=0.480-0.745) were significant predictors of treatment result. And insurance type(OR=1.527, CI=1.241-1.879), CCI(3 over, OR=1.865, CI=1.534-2.266), operation(OR=5.399, CI=4.562-6.389), disposition(OR=1.279, CI=1.013-1.614), district(Metropolitan city, OR=0.519, CI=0.407-0.661; Non-metropolitan OR=0.469, CI=0.383-0.574), beds(500-999, OR=2.799, CI=1.986-3.944; 1000 over, OR=2.109, CI=1.429-3.113) were significant predictors of early complication. This research would be used as a basic data of high quality of medical care and efficient resource utilization in order to detect and minimize the negative medical treatment results of inpatients with psychiatric comorbidity.