http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
안정남,김좌경,이형석,김성균,김형직,송영림 대한신장학회 2022 Kidney Research and Clinical Practice Vol.41 No.5
Background: Sarcopenia is a prevalent complication in patients with chronic kidney disease and is associated with poor quality of life, morbidity, and mortality. Several candidate biomarkers have been evaluated for this condition. This study assessed the serum cystatin C to creatinine (serum cystatin C/Cr) ratio as a potential biomarker for sarcopenia in patients with non-dialysis-dependent chronic kidney disease. Methods: This study enrolled 517 outpatients. Muscle mass (lean tissue index) was measured using a bioimpedance spectroscopic device, and muscle strength (handgrip strength) was also measured. Sarcopenia was defined as a combination of low muscle strength and low muscle mass. Results: Sarcopenia was observed in 25.5% of patients, and the mean serum cystatin C/Cr ratio was significantly higher in patients with sarcopenia than in those without it (1.14 ± 0.26 vs. 1.01 ± 0.27, p < 0.001). The prevalence of sarcopenia and low lean tissue index increased as the cystatin C/Cr ratio increased. The negative predictive value of the cystatin C/Cr ratio for sarcopenia or low lean tissue index was ≥80%. Multivariate analyses revealed that when the serum cystatin C/Cr ratio increased by 1, the risk of sarcopenia, low lean tissue index, and low handgrip strength increased by 4.6-, 7.2-, and 2.6-fold, respectively (p = 0.003, p < 0.001, and p = 0.048). The association was maximized in patients with an estimated glomerular filtration rate of <30 mL/min/1.73 m2. Conclusion: Calculating the serum cystatin C/Cr ratio could be helpful for detecting and managing sarcopenia in patients with chronic kidney disease.
DEA 방법론을 이용한 온라인 판매자 추천 시스템의 구축
안정남(Jungnam An),노상규(Sangkyu Rho),유병준(Byungjoon Yoo) 한국전자거래학회 2011 한국전자거래학회지 Vol.16 No.3
구매자와 판매자의 판매과정에서 ‘구매가치’는 구매자의 구매의사결정에 있어서 매우 중요한 가격대비 질의 중요한 측정치이다. 본 논문의 목적은 온라인 구매자들이 동일한 물건을 파는 판매자들 중에 최적 판매자를 선택하는 데 도움이 되는 방법론을 제안함에 있다. 이 방법론 수립을 위하여 DEA(data envelopment analysis) 방법론의 적용모형의 하나인 FDH(free disposal hull) 모형을 사용하고, 이 모형의 실효성을 실제 가격비교 사이트로부터 획득한 데이터를 이용하여 검증하였다. 모형 검증과정에서는 가격, 브랜드, 배달 기간 등 거래 조건에 대하여 구매자들이 어떻게 반응하는지를 우선 분석하고, 이를 바탕으로 구매자의 구매 의사결정을 돕는 판매자 추천 시스템을 구축하였다. 본 연구를 통하여 검증된 FDH 모형은, 구매자 측면에서 최적조건, 최저가로 좋은 제품과 서비스를 원하는 구매자에게 유용한 정보를 제공하고, 나아가 자동화된 소규모 거래에도 활용될 수 있을 것으로 기대된다. 판매자 측면에서는, 구매자의 선호도를 더욱 자세히 파악함으로써 타판매자 대비 경쟁력을 가지는 벤치마킹 전략을 수립하는 데에도 유용하게 이용될 수 있을 것으로 기대된다. In a buyer-seller transaction process, ‘value for money,’ a measure of quality-priceratio, is one of the most important criteria for buyers’ purchasing decisions. The purpose of this paper is to suggest a method which helps online shoppers choose the best of several sellers offering homogeneous goods. We suggest FDH (free disposal hull) model, an applied model of data envelopment analysis (DEA), for online buyer-seller transactions and verify it with the data from an Internet comparison shopping site. For this purpose, we analyze consumer choice behaviors by examining how consumers respond to different sale conditions such as price, brand, or delivery time. Then, we implement a seller recommendation system to support buyers’ purchasing decisions. We expect our FDH model to provide valuable information for rational buyers who want to pay the least price for high quality products/services and to be used in implementing automated evaluation processes in micro transactions. Moreover, we expect that our results can be utilized for sellers’ benchmarking strategies which help sellers be more competitive by showing them how to attract buyers.
안정남,최윤호 경기대학교 부설 산업기술종합 연구소 1998 산업기술종합연구소 논문집 Vol.16 No.-
In this paper, fuzzy navigation controller is designed for the autonomous navigation of a mobile robot, and then it is applied to an implemented mobile robot system. In designing fuzzy controller, a left wall following navigation method, a right wall following navigation method and a centered following navigation are used respectively. The input for wall following navigation is the difference of distance between navigation lines and that of angle, the output is angular velocity. In addition, Mamdani's method is used for inference, and the center of gravity is used for defuzzification. To evaluate performance and applicability of the designed fuzzy navigation controller, the experiment is performed through the computer simulation and the implemented mobile robot in which the ultrasonic sensors are used for acquiring the distance data. The results of a simulation and a real navigation experiment show that our designed fuzzy controller performs well.