最適化 技法에 의한 南江-安東댐의 洪水調節

李成允,金勝權 외 1인 空軍士官學校 1988 論文集 Vol.25 No.-

The use of an Incremental Dynamic Programming(IDP) for real-time flood control operation is investigated. The optimization model has been applied for the Namgang and Andong hypothetical flood control system in the Nakdong river basin. The objective of the operation is defined to minimize the maximum flow at the confluense of downstreams from the two reservoirs. The results are compared to the direct summation of the flood routing results from individual flood control simulation run. It shows that peak flow at the confluence is reduced markedly by reducing peak outflows from individual reservoirs and by balancing the time of the peak release between the two reservoirs.

식도암의 임상적 고찰

이성윤,지행옥,Lee, Seong-Yun,Ji, Haeng-Ok 대한흉부심장혈관외과학회 1990 Journal of Chest Surgery (J Chest Surg) Vol.23 No.2

The records of 67 patients who had been operated as an esophageal cancer during the period from 1973 to 1989 at the Department of Thoracic and Cardiovascular Surgery, Hanyang University Hospital were reviewed retrospectively. The results were summarized as follows ; The age ranged from 28 years old to 80 years old. The highest incidence was 5th decades, then 6th decades, and the incidence of male was 10 times as the incidence of female[M:F= 10.16: 1]. The locations were lower esophagus 44%, middle esophagus 38.8%, upper esophagus 11.9% and cervical esophagus 4.4% The frequent symptoms were dysphagia [88%], epigastric or substernal pain and discomfort [29.8%], weight loss [20.8%], and laryngeal dryness [1.4%]. The most common interval between the onset of dysphagia and admission was 2-3 months; 82% of patients was within 6 months, The cancer consisted of stage I [3%], stage II [11.9%], stage III[47.6%], and stage IV [33.7%] The resectability of cancer was 67%. The organs of substitute were stomach in 21 cases, right colon 6 cases, and jejunum in 8 CRSCS. The relation between invasion of tumor and lymph node metastasis was analyzed: mucosal involvement: 1 case/2case, muscle invasion; 0/2 full thickness; 4/6, adjacent structure 7/12. Postoperative complications were pneumonia, pleural effusion, hoarseness, mediastinitis, anastomosis site leakage, reoperation due to stenosis, chylothorax, empyema, mechanical ileus, wound infection, meat impaction at anastomosis site, and repair of gastrostomy site leakage. Adjuvant therapies were irradiation [15cases], chemotherapy [14cases], and Bougie dilatation [4 cases],

우리나라 요양보호사 양성에 따른 문제점 및 개선 방안 연구

이성윤 한국보건복지학회 2009 보건과 복지 Vol.11 No.-

未熱兒의 知能指數에 關한 硏究

李聖允 醫藥係社 1963 綜合 醫學 Vol.8 No.11

카페인 투여가 조정선수의 조정 에그로메타 2000m 기록 및 산소섭취량에 미치는 영향

이성윤 한국스포츠리서치 2002 한국 스포츠 리서치 Vol.13 No.3

우리나라 해운기업의 운전자본관리와 수익성과의 관계에 관한 실증연구

이성윤,Sung-Yhun Lee 한국항해항만학회 2015 한국항해항만학회지 Vol.39 No.3

기업의 운전자본관리는 단기재무전략관리 차원에서 접근이 가능하며, 이는 기업의 유동성 및 수익성 등에 영향관계가 있음이 실증 되고 있다. 따라서 효율적인 운전자본관리는 기업의 수익성을 증대시킬 수 있을 뿐만 아니라, 유동성 또한 개선시킬 수 있게 된다. 해운기업 의 경우 글로벌금융위기와 맞물려 수익성과 유동성에 많은 어려움을 겪었음에도 불구, 운전자본관리와 수익성에 대한 연구는 전무한 상태이 다. 이에 본 연구에서는 2004년 이후 46개 해운기업을 대상으로 운전자본관리와 수익성과의 관계를 규명함으로써 단기재무전략 수립에 유용 한 정보를 제공하고자 하였다. 연구의 결과 기존연구들과 같이 매입채무기간, 재고기간, 현금주기, 영업주기가 해운기업의 수익성 즉, 매출액 총이익률과 매출액영업이익률을 개선할 수 있는 중요한 요인인 것으로 실증되었다. 특히 매입채무신용기간과 영업주기의 증가는 수익성의 증 가를 가져오는 것으로 분석된 반면, 재고기간과 현금주기는 부(-)의 관계를 보여 이들이 줄어들 경우 수익성이 증가하는 것으로 나타났다. 매 출채권기간은 일부 모형에서 유의하였으나, 기존 연구들과는 달리 해운기업의 경우 수익성과의 관계를 설명하기에는 한계가 있는 것으로 나타났다. Many of previous studies suggested that working capital management is an important component of firm’s financial decision and efficient working capital management affects firms‘ profitability and it’s value. Recently, Korean shipping firms have been suffering from financial distress by recession of shipping economy. In this point of view, this study tries to investigate the relationship between working capital management and shipping firm’s profitability, using panel data on 46 Korean shipping firms for the period of 2004-2013. As result of panel regression, it proved that average payment period, inventory turnover, cash conversion cycle and operating cycle are significantly associated with firms profitabilities such as profit margin ratio and operating profit ratio, and the manager of shipping firm can increase firms profitability by more efficient working capital management. There are strong positive relationships between average payment period and operating cycle and firm’s profitability. These results suggest that managers can create firm’s value by increasing average payment period and operating cycle. Otherwise inventory turnover and cash conversion cycle have negative relationships with firm’s profitability. It means that managers can increase firm’s profitability by reducing these variables

정중 흉골 절개술을 통한 양측의 기종성 폐포의 절제

이성윤 대한흉부심장혈관외과학회 1990 Journal of Chest Surgery (J Chest Surg) Vol.23 No.4

The complicated pulmonary emphysema including “Giant bullae” and spontaneous pneumothorax often involve both lungs, and controversy exists concerning which is the more rational means of surgical treatment-bilateral simultaneous operation or two staged operation. We report three cases of the complicated bilateral bullous emphysema and two cases of bilateral spontaneous pneumothorax treated through median sternotomy. We performed the ligation of bullae, bullectomy, cystectomy, wedge resection, and left lower lobectomy through median sternotomy. No technical problems were encountered through this approach, which provided maximum benefit with one operation In conclusions, median sternotomy may be appropriate for resection of emphysematous bullae, specially in a severe COPD patient who may be poorly tolerated the superimposed loss of respiratory function due to incisional pain, because median sternotomy permit bilateral exploration, minimal impairment of pulmonary function, simultaneous restoration of pulmonary function, less incisional pain than routine lateral thoracotomy.

Improved Dielectric Properties of CaCu3Ti4O12 films with a CaTiO3 Interlayer on Pt/TiO2/SiO2/Si Substrates Prepared by Pulsed Laser Deposition

이성윤,김휘은,조윌렴,김영환,유상임 대한금속·재료학회 2015 ELECTRONIC MATERIALS LETTERS Vol.11 No.6

We report the greatly improved dielectric properties of CaCu3Ti4O12 (CCTO) films with a 60 nm-thick CaTiO3 (CTO) interlayer on Pt/TiO2/ SiO2/Si substrates. Both CCTO films and CTO interlayers were prepared by pulsed laser deposition (PLD). With increasing the thickness of CCTO from 200 nm to 1.3 μm, the dielectric constants (εr) at 10 kHz in both CCTO single-layered and CCTO/CTO double-layered films increased from ~260 to ~6000 and from ~630 to ~3700, respectively. Compared with CCTO single-layered films, CCTO/CTO double-layered films irrespective of CCTO film thickness exhibited a remarkable decrease in their dielectric losses (tanδ) (<0.1 at the frequency region of 1 - 100 kHz) and highly reduced leakage current density at room temperature. The reduced leakage currents in CCTO/ CTO double-layered films are attributable to relatively higher trap ionization energies in the Poole-Frenkel conduction model.

2004년도 제9회 연수강좌 : 비만환자에서의 내피세포 기능장애: 심장혈관병과 당뇨병으로의 출발점인가?

이성윤 대한비만학회 2004 대한비만학회 학술대회 Vol.- No.-

ARIMA와 VAR·VEC 모형에 의한 부산항 물동량 예측과 관련성연구

이성윤,안기명 한국항해항만학회 2020 한국항해항만학회지 Vol.44 No.1

세계적인 장기경기침체 속에서 보다 정확한 물동량 예측은 항만정책 수행에 중요하다. 따라서, 본 연구에서는 부산항 컨테이너 물동량(수출입화물과 환적화물)을 단변량 모형인 ARIMA 뿐만 아니라 인과관계가 있을 것으로 예상되는 경제규모(한국, 중국, 미국의 국내총생산), 금리수준 그리고 경기변동을 고려한 벡터자기회귀모형과 벡터오차수정모형을 활용하여 추정하고 비교하였다. 측정자료는 2014년 1월부터 2019년 8월까지 월별 부산항 컨테이너 물동량이다. 분석결과에 의하면, 수출입물동량 시계열은 비교적 안정적(stationary)이어서 VAR에 의해 추정하였고 환적화물은 불안정적(non-stationary)하지만, 경제규모, 금리 및 경기변동과 공적분(장기적인 균형관계)를 띠고 있어 VEC모형으로 추정하였다. 추정결과, 안정적인 수출입화물 추정에서는 단변량 모형인 ARIMA가 우수하고 추세가 있는 환적화물은 다변량모형인 VEC모형이 보다 예측력이 우수한 것으로 나타나고 있다. 특히 수출입화물은 우리나라 경제규모와 관련이 있고, 환적화물은 중국과 미국 경제규모와 밀접한 관련이 있다. 또한 중국 경제규모가 미국에 비하여 더 밀접하게 나타나고 있어 환적화물 증대전략에 시사점을 주고 있다. More accurate forecasting of port cargo in the global long-term recession is critical for the implementation of port policy. In this study, the Busan Port container volume (export cargo and transshipment cargo) was estimated using the Vector Autoregressive (VAR) model and the vector error correction (VEC) model considering the causal relationship between the economic scale (GDP) of Korea, China, and the U.S. as well as ARIMA, a single volume model. The measurement data was the monthly volume of container shipments at the Busan port January 2014-August 2019. According to the analysis, the time series of import and export volume was estimated by VAR because it was relatively stable, and transshipment cargo was non-stationary, but it has cointegration relationship (long-term equilibrium) with economic scale, interest rate, and economic fluctuation, so estimated by the VEC model. The estimation results show that ARIMA is superior in the stationary time-series data (local cargo) and transshipment cargo with a trend are more predictable in estimating by the multivariate model, the VEC model. Import-export cargo, in particular, is closely related to the size of our country's economy, and transshipment cargo is closely related to the size of the Chinese and American economies. It also suggests a strategy to increase transshipment cargo as the size of China's economy appears to be closer than that of the U.S.