• 한국농공학회논문집
• /
• 제46권5호
• /
• pp.15-26
• /
• 2004

This study was conducted to derive the regional design rainfall by the regional frequency analysis based on the regionalization of the precipitation. The optimal regionalization of the precipitation data were classified by the above mentioned regionalization for all over the regions except Jeju and Ulleung islands in Korea. Design rainfalls following the consecutive duration were derived by the regional analysis using the observed and simulated data resulted from Monte Carlo techniques. Relative root mean square error (RRMSE), relative bias (RBIAS) and relative reduction (RR) in RRMSE for the design rainfall were computed and compared between the regional and at-site frequency analysis. It has shown that the regional frequency analysis procedure can substantially more reduce the RRMSE, RBIAS and RR in RRMSE than those of at-site analysis in the prediction of design rainfall. Consequently, optimal design rainfalls following the classified regions and consecutive durations were derived by the regional frequency analysis using Generalized extreme value distribution which was identified to be more optimal one than the other applied distributions. Diagrams for the design rainfall derived by the regional frequency analysis using L-moments were drawn according to the regions and consecutive durations by GIS techniques.

• 한국농공학회논문집
• /
• 제46권4호
• /
• pp.25-36
• /
• 2004

This study was conducted to derive the design rainfall by the consecutive duration using the at-site frequency analysis. Using the errors, K-S tests and LH-moment ratios, Log Pearson type 3 (LP3) and Generalized Extreme Value (GEV) distributions of Gamma and Non-Gamma Family, respectively were identified as the optimal probability distributions among applied distributions. Parameters of GEV and LP3 distributions were estimated by the method of L and LH-moments and the Indirect method of moments respectively. Design rainfalls following the consecutive duration were derived by at-site frequency analysis using the observed and simulated data resulted from Monte Carlo techniques. Relative root-mean-square error (RRMSE) and relative efficiency (RE) in RRMSE for the design rainfall derived by at-site analysis in the observed and simulated data were computed and compared. It has shown that at-site frequency analysis by GEV distribution using L-moments is confirmed as more reliable than that of GEV and LP3 distributions using LH-moments and Indirect method of moments in view of relative efficiency.

• 한국정보과학회논문지:소프트웨어및응용
• /
• 제32권3호
• /
• pp.181-191
• /
• 2005

본 논문에서는 컴퓨터그래픽으로 구현된 인체에 착용되는 의류의 시뮬레이션을 위한 수치해석알고리즘 및 소프트웨어 개발을 수행하였다. 개발된 알고리즘은 수학적으로 elliptical 흑은 비순차적인 성질을 가지는 두 개의 켤레조화함수(conjugate harmonic functions)들을 사용하여, 지나간 시간단계(time step)에서의 견과에 의존하지 않고 매 순간의 역학적 균형만으로 의류에 형성되는 주름의 형태를 표현한다. Global-local 해석기법을 채택하여 global 스케일에서의 전체적인 변형과 local 스케일에서의 부분적인 변형으로 나누었으며, 이 두 가지 스케일에서의 해석 결과가 선형적으로 중첩될 수 있음을 가정하였다. Global 해석에서는 신체 각 부위의 회전이나 평행이동, 뒤틀림 등의 전반적인 변형에 따른 인체와의 접촉점의 변화와 응력을 고려하였다. Local 해석에서는 국소적인 주름의 형상을 얻기 위해 주름의 진폭등고선과 주름의 방향 사이의 직교성을 가정하여 단순화 시켰다. 본 제안 방법은 불연속적으로 변화하는 두 개의 서로 다른 자세에 대해서도 중간단계 해석을 위한 시간증분의 삽입이 불필요하며, 기존의 방식에서 주로 사용되는 시간적분의 방법을 채택하지 않으므로 연산 시간의 절감과 안정성의 향상이 이루어졌다. 임의의 두 자세 사이의 연속 동작을 시뮬레이션 함에 있어서도 두 정지 자세 사이의 움직임을 보간법으로 구현하여 연속적인 의류의 변형을 구현할 수 있었다.

• 한국수자원학회:학술대회논문집
• /
• 한국수자원학회 2017년도 학술발표회
• /
• pp.424-424
• /
• 2017

Several studies of the world have analyzed the regional rainfall trends in large data sets. However, it reported that the long-term behavior of rainfall was different on spatial and temporal scales. The objective of this study is to determine the local trends of rainfall indices in the Yom River Basin, Thailand. The rainfall indices consist of the annual total precipitation (PRCTPOP), number of heavy rainfall days ($R_{10}$), number of very heavy rainfall days ($R_{20}$), consecutive of dry days (CDD), consecutive of wet days (CWD), daily maximum rainfall ($R_{x1}$), five-days maximum rainfall ($R_{x5}$), and total of annual rainy day ($R_{annual}$). The rainfall data from twelve hydrological stations during the period 1965-2015 were used to analysis rainfall trend. The Mann-Kendall test, which is non-parametric test was adopted to detect trend at 95 percent confident level. The results of these data were found that there is only one station an increasing significantly trend in PRCTPOP index. CWD, which the index is expresses longest annual wet days, was exhibited significant negative trend in three locations. Meanwhile, the significant positive trend of CDD that represents longest annual dry spell was exhibited four locations. Three out of thirteen stations had significant decreasing trend in $R_{annual}$ index. In contrast, there is a station statistically significant increasing trend. The analysis of $R_{x1}$ was showed a station significant decreasing trend at located in the middle of basin, while the $R_{x5}$ of the most locations an insignificant decreasing trend. The heavy rainfall index indicated significant decreasing trend in two rainfall stations, whereas was not notice the increase or decrease trends in very heavy rainfall index. The results of this study suggest that the trend signal in the Yom River Basin in the half twentieth century showed the decreasing tendency in both of intensity and frequency of rainfall.

• 대한수학회보
• /
• 제59권3호
• /
• pp.617-642
• /
• 2022

For positive integers n and d with d < n, an n × n array A based on 𝒳 = {0, 1, …, nd} is called a sparse anti-magic square of order n with density d, denoted by SAMS(n, d), if each non-zero element of X occurs exactly once in A, and its row-sums, column-sums and two main diagonal-sums constitute a set of 2n + 2 consecutive integers. An SAMS(n, d) is called regular if there are exactly d non-zero elements in each row, each column and each main diagonal. In this paper, we investigate the existence of regular sparse anti-magic squares of order n ≡ 1, 5 (mod 6), and prove that there exists a regular SAMS(n, d) for any n ≥ 5, n ≡ 1, 5 (mod 6) and d with 2 ≤ d ≤ n - 1.

• 한국관광식음료학회지:관광식음료경영연구
• /
• 제15권1호
• /
• pp.81-97
• /
• 2004

The purpose of this study is to suggest management information through the analysis of relationships between financial characteristics and financial performance to the owners and managers of super deluxe hotels in Korea. The data of super deluxe hotels were collected by the electronic F/S announcement system. Forty-two hotels, which have financial statements for the previous three consecutive years were chosen as the sample of analysis. Return on total assets and times interest earned, asset turnover, current ratio of the super deluxe hotels are correlated. Return on total assets and asset turnover, sales growth rate, times interest earned are also correlated. And productivity and asset turnover of chain hotels are correlated. Based on this study, it can be concluded that chain hotels are maily correlated with growth ratio and activity ratio. Otherwise non-chain hotels are mainly correlated with current ratio and safety ratio.

• Journal of Forest and Environmental Science
• /
• 제38권4호
• /
• pp.219-228
• /
• 2022

This study examined the relationship between the number of forest fires and days with no rainfall based on the national forest fire statistics data of the Korea Forest Service and meteorological data from the Open MET Data Portal of the Korea Meteorological Administration (KMA; data.kma.go.kr) for the last 30 years (1991-2021). As for the trend in precipitation amount and non-rainfall days, the rainfall and the days with rainfall decreased in 2010 compared to those in 1990s. In terms of the number of forest fires that occurred in February-May accounted for 75% of the total number of forest fires, followed by 29% in April and 25% in March. In 2000s, the total number of forest fires was 5,226, indicating the highest forest fire activity. To analyze the relationship between regional distribution of non-rainfall periods (days) and number of forest fires, the non-rainfall period was categorized into five groups (0 days, 1-10 days, 11-20 days, 21-30 days, and 31 days or longer). During the spring fire danger season, the number of forest fires was the largest when the non-rainfall period was 11-20 days; during the autumn fire precaution period, the number of forest fires was the largest when the non-rainfall period was 1-10 days, 11-20 days, and 21-30 days, showing differences in the duration of forest fire occurrence by region. The 30-year trend indicated that large forest fires occurred only between February and May, and in terms of the relationship with the non-rainfall period groups, large fires occurred when the non-rainfall period was 1-10 days. This signifies that in spring season, the dry period continued throughout the country, indicating that even a short duration of consecutive non-rainfall days poses a high risk of large forest fires.

• Archives of Plastic Surgery
• /
• 제47권3호
• /
• pp.242-249
• /
• 2020

Background The Exoscope is a novel high-definition digital camera system. There is limited evidence signifying the use of exoscopic devices in microsurgery. This trial objectively assesses the effects of the use of the Exoscope as an alternative to the standard operating microscope (OM) on the performance of experts in a simulated microvascular anastomosis. Methods Modus V Exoscope and OM were used by expert microsurgeons to perform standardized tasks. Hand-motion analyzer measured the total pathlength (TP), total movements (TM), total time (TT), and quality of end-product anastomosis. A clinical margin of TT was performed to prove non-inferiority. An expert performed consecutive microvascular anastomoses to provide the exoscopic learning curve until reached plateau in TT. Results Ten micro sutures and 10 anastomoses were performed. Analysis demonstrated statistically significant differences in performing micro sutures for TP, TM, and TT. There was statistical significance in TM and TT, however, marginal non-significant difference in TP regarding microvascular anastomoses performance. The intimal suture line analysis demonstrated no statistically significant differences. Non-inferiority results based on clinical inferiority margin (Δ) of TT=10 minutes demonstrated an absolute difference of 0.07 minutes between OM and Exoscope cohorts. A 51%, 58%, and 46% improvement or reduction was achieved in TT, TM, TP, respectively, during the exoscopic microvascular anastomosis learning curve. Conclusions This study demonstrated that experts' Exoscope anastomoses appear non-inferior to the OM anastomoses. Exoscopic microvascular anastomosis was more time consuming but end-product (patency) in not clinically inferior. Experts' "warm-up" learning curve is steep but swift and may prove to reach clinical equality.

• Clinical Endoscopy
• /
• 제56권1호
• /
• pp.75-82
• /
• 2023

Background/Aims: The etiology of superficial non-ampullary duodenal epithelial tumors (SNADETs) remains unclear. Recent studies have reported conflicting associations between duodenal tumor development and Helicobacter pylori infection or endoscopic gastric mucosal atrophy. As such, the present study aimed to clarify the relationship between SNADETs and H. pylori infection and/or endoscopic gastric mucosal atrophy. Methods: This retrospective case-control study reviewed data from 177 consecutive patients with SNADETs who underwent endoscopic or surgical resection at seven institutions in Japan over a three-year period. The prevalence of endoscopic gastric mucosal atrophy and the status of H. pylori infection were compared in 531 sex- and age-matched controls selected from screening endoscopies at two of the seven participating institutions. Results: For H. pylori infection, 85 of 177 (48.0%) patients exhibited SNADETs and 112 of 531 (21.1%) control patients were non-infected (p<0.001). Non-atrophic mucosa (C0 to C1) was observed in 96 of 177 (54.2%) patients with SNADETs and 112 of 531 (21.1%) control patients (p<0.001). Conditional logistic regression analysis revealed that non-atrophic gastric mucosa was an independent risk factor for SNADETs (odds ratio, 5.10; 95% confidence interval, 2.44-8.40; p<0.001). Conclusions: Non-atrophic gastric mucosa, regardless of H. pylori infection status, was a factor independently associated with SNADETs.

• 환경생물
• /
• 제36권4호
• /
• pp.488-497
• /
• 2018

형질전환 벼와 일반 벼의 환경위해성 평가 기초자료를 위해 경상남도 사천시에서 2013~2017년, 경상북도 군위군에서 2015~2016년 7월 말부터 10월 초까지 벼에 발생하는 곤충상을 조사하고 군집특성을 분석하여 비교하였다. 사천시에서 형질전환 벼는 경상대학교 LMO (Living genetically Modified Organism) 격리포장 내에서 재배되었고, 일반 벼는 경상남도 사천시 사천읍 두량리에서 재배되었다. 군위군에서 형질전환 벼는 경북대학교 LMO 격리포장 내에서 재배되었고, 일반 벼는 경상북도 군위군 효령면 화계리에서 재배되었다. 채집방법으로 육안 조사, 포충망 조사, 유아등 트랩, 끈끈이 트랩을 이용하였다. 5년 동안 사천시에서 총 15목 123과 464종 37,941개체가 채집되었고, 2년 동안 군위군에서 총 13목 111과 366종 10,030개체가 채집되었다. 다년간 LMO포장과 일반포장을 비교해본 결과 매년 상위 주요 목은 우점 순서를 제외하면 거의 같은 목이 나타나는 것을 보아 아직까지는 LMO포장과 일반포장의 차이가 뚜렷하게 나타나지 않았다고 사료된다. 그리고 LMO포장과 일반포장 사이의 유사도 지수와 일반포장 사이의 유사도 지수가 차이가 없는 것으로 보아 LMO로 인한 차이가 아닌 환경에 의한 차이로 사료된다.