• 농촌계획
• /
• 제10권1호
• /
• pp.1-7
• /
• 2004

There are recently many studies on evaluating the economic value of multi-functionality of rural areas. However, the regional difference of economic value leads a problem of different evaluation on its economic value for each region in its application to government policy. This problem causes an increase in cost because it creates restriction in policy decisions which put their importance on the time of their execution. This study investigates the propriety of value transfer using Meta Analysis after evaluating the social and cultural value of rural areas among their functions based on CVM model. It finds that the regional difference in the willingness to pay is 0.13% to 31.42%.

• 응용통계연구
• /
• 제25권1호
• /
• pp.205-213
• /
• 2012

선형회귀모형에서 자료를 모형에 적합시킬 때 일반적으로 반응변수 변환을 시도하지만 적절한 변환함수의 결정은 몇개의 이상치들에 민감하게 반응한다는 것이 잘 알려져 있다. 이에 따라 이상치에 영향을 받지 않는 변수변환 방법들이 연구, 개발되고 있으나 최근에 Cheng (2005)에 의해 최소절사제곱추정치에 기반을 둔 절사 우도추정치 방법처럼 이상치의 숫자를 미리 정해야한다거나 많은 계산량이 필요하다는 단점들을 갖고 있다. 본 논문에서는 그와 같은 문제점을 해결하고 추정치의 강건성을 개선하는 새로운 방법을 제안하며 제안된 방법에서는 반응변수 변환에 따른 이상치 탐색법에 있어서 Hadi와 Simonoff (1993)가 제시한 단계적 절차를 응용, 적용한다.

• Steel and Composite Structures
• /
• 제32권4호
• /
• pp.455-466
• /
• 2019

Despite the rapid advancement in computing resources, many real-life design and optimization problems in structural engineering involve huge computation costs. To counter such challenges, approximate models are often used as surrogates for the highly accurate but time intensive finite element models. In this paper, surrogates for first-order shear deformation based finite element models are built using a polynomial regression approach. Using statistical techniques like Box-Cox transformation and ANOVA, the effectiveness of the surrogates is enhanced. The accuracy of the surrogate models is evaluated using statistical metrics like $R^2$, $R^2{_{adj}}$, $R^2{_{pred}}$ and $Q^2{_{F3}}$. By combining these surrogates with nature-inspired multi-criteria decision-making algorithms, namely multi-objective genetic algorithm (MOGA) and multi-objective particle swarm optimization (MOPSO), the optimal combination of various design variables to simultaneously maximize fundamental frequency and frequency separation is predicted. It is seen that the proposed approach is simple, effective and good at inexpensively producing a host of optimal solutions.

• 대한영양사협회학술지
• /
• 제26권4호
• /
• pp.243-253
• /
• 2020

The purpose of this study was to set new guidelines for adenosine triphosphate (ATP) bioluminescence hygiene monitoring of distribution trays at children's foodservices. Five dietitians visited 223 foodservices (95 institutional, 128 small) to examine whether they adhered to the norms of 'Keeping distribution tray sanitary by washing/sanitizing' and 'Performing food distribution in a clean and appropriate way'. In this visit, dietitians swabbed 100 ㎠ area of the distribution trays twice, once for obtaining ATP measurements and the second time for Aerobic Plate Counts (APC) using 3M Petrifilm Plates. Chi-square test and ANOVA were applied using SPSS 23.0 software. SPSS 23.0 was used to conduct graphical and statistical analysis of the raw data of ATP measurements, which were further transformed by a Box-Cox transformation. The mean of APC from all the subjects inspected was 3.8×10²±2,102.0 CFU/100 ㎠. A total of 208 (93.3%) trays were observed within the acceptable limits of APC (Pass<5.0×10² CFU/100 ㎠). APCs taken at institutional foodservices showed significantly lower levels (1.4×10²±600.0 CFU/100 ㎠, P<0.01) compared to the small foodservices (5.5×10²±2,718.7 CFU/100 ㎠). No significant differences were observed between the two groups in ATP measurements and in the performance rate of 2 checklist items. As against the 93.3% APC adequacy from the total subjected inspection, total ATP adequacy (Pass≤300 RLU/100 ㎠) was only 71.7%. Therefore, more practical guidelines should be prepared for the assessment of the hygiene of distribution trays. In the graphical and statistical analysis, levels below 250 RLU/100 ㎠ was considered 'Pass', while equal to or greater than 350 RLU/100 ㎠ was considered 'Fail' for distribution trays.

• 한국수자원학회:학술대회논문집
• /
• 한국수자원학회 2022년도 학술발표회
• /
• pp.141-141
• /
• 2022

Drought is a global phenomenon that affects almost all landscapes and causes major damages. Due to non-linear nature of contributing factors, drought occurrence and its severity is characterized as stochastic in nature. Early warning of impending drought can aid in the development of drought mitigation strategies and measures. Thus, drought forecasting is crucial in the planning and management of water resource systems. The primary objective of this study is to make improvement is existing drought forecasting techniques. Therefore, we proposed an improved version of Seasonal Autoregressive Integrated Moving Average (SARIMA) model (MD-SARIMA) for reliable drought forecasting with three years lead time. In this study, we selected four watersheds of Han River basin in South Korea to validate the performance of MD-SARIMA model. The meteorological data from 8 rain gauge stations were collected for the period 1973-2016 and converted into watershed scale using Thiessen's polygon method. The Standardized Precipitation Index (SPI) was employed to represent the meteorological drought at seasonal (3-month) time scale. The performance of MD-SARIMA model was compared with existing models such as Seasonal Naive Bayes (SNB) model, Exponential Smoothing (ES) model, Trigonometric seasonality, Box-Cox transformation, ARMA errors, Trend and Seasonal components (TBATS) model, and SARIMA model. The results showed that all the models were able to forecast drought, but the performance of MD-SARIMA was robust then other statistical models with Wilmott Index (WI) = 0.86, Mean Absolute Error (MAE) = 0.66, and Root mean square error (RMSE) = 0.80 for 36 months lead time forecast. The outcomes of this study indicated that the MD-SARIMA model can be utilized for drought forecasting.