풍공학분야에 특화된 학술지인 한국풍공학회지에서 발간된 논문에 대해 토픽모델링 기법 중 잠재의미분석(LSA)와 잠재디리 크레할당(LDA)을 적용하여 연구주제 추출의 적합성을 비교 평가하였다. 토픽간의 유사도를 평가하기 위해 문서토픽행렬을 이용한 상 관분석법을 제안하였으며, 이를 적용하여 문서단어행렬의 특성벡터로부터 토픽을 추출하는 LSA 대비 단어의 결합확률을 이용하는 LDA가 토픽 구성단어를 2배 이상 사용하여 보다 독립적인 토픽을 추출하였다는 평가결과를 얻었다. 학술지의 연구주제를 종합하면 ‘building’, ‘bridge’를 ‘연구대상’으로 ‘wind speed’, ‘wind load’, ‘vibration control’을 ‘연구목적’으로 ‘wind tunnel test’, ‘numerical method’의 ‘연구방법’을 사용하였다. 향후 토픽모델링은 연구주제를 ‘연구대상’, ‘연구목적’, ‘연구방법’의 구조적인 결합으로 정의하여 단어의 사용특성을 반영하는 방식으로 개선되어야 할 것으로 사료된다.

국내 중·저준위 방사성폐기물 처분시설로 고려되고 있는 표층처분시설의 불포화대에서 핵종 이동을 야기하는 지하수 유동을 평가하기 위하여 유한요소법 기반의 COMSOL Multiphysics을 이용한 수치모델을 개발하였다. 그리고, 처분장 가장자리 를 대상으로 처분고, 뒤채움재, 처분덮개로 구성되는 표층처분시설과 그 아래에 위치한 불포화대를 포함한 수직 2차원의 모델 영역을 구성하여, 시나리오 별 모델링을 수행하였다. 지속적 강수 유입 조건과 간헐적 강수 유입 조건 비교에서 포화도의 파동 현상을 제외하고는 뚜렷한 차이점을 보이지 않는 것으로 판단되었다. 불포화대의 공극률이나 잔류함수비와 같은 입력 자료는 전반적으로 불포화대 지하수 유동에 큰 영향도가 없는 것으로 판단되었다. 하지만, 불포화대의 수리전도도는 지하수 유동에 큰 영향을 미치는 것으로 판단되었다. 즉, 처분고로의 지하수 유입 속도를 판단하기 위해서는 불포화대의 수리전도도 특성이 신중하게 고려되어야 할 것으로 판단되었다.

The distribution of wild boar (Sus scropa) in the Republic of Korea was forecasted using environmental factors. A species distribution model was applied with the standard normalized difference vegetation index (NDVI), enhanced vegetation index (EVI), solar zenith angle (SUNZ), daytime land surface temperature (dTemp), and nighttime land surface temperature (nTemp). Understanding wild boar distribution is important for controlling African swine fever (ASF) because the disease could be endemic in wild boar or spread from wild boars to domestic pigs. Among the five predictors, the NDVI was the most influencing factor for the wild boar distribution. The relative contributions of the predictors were 67.4 for NDVI, 16.9 for dTemp, 10.5 for SUNZ, 4.4 for EVI, and 0.8 for nTemp. The area size under the receiver-operating curve of the receiver-operating characteristics for the current model was 0.62, but the real wild boar observation data overlapped with the predicted high-density wild boar distribution area. The wild boar distribution density was relatively higher in Gangwon-do, Gyeongsangbuk-do, Gyeongsangnam-do, and Jeollanam-do. Given the ASF epidemics, contact between ASF-infected animals and ASF-susceptible animals in high-density wild boar distribution areas should be prevented by long-range fencing or active surveillance.

The fatigue characteristics of glass fiber reinforced plastic (GFRP) composites were studied under repeated loads using the finite element method (FEM). To realize the material characteristics of GFRP composites, Digimat, a mean-field homogenization tool, was employed. Additionally, the micro-structures and material models of GFRP composites were defined with it to predict the fatigue behavior of composites more realistically. Specifically, the fatigue characteristics of polybutylene terephthalate with short fiber fractions of 30wt% were investigated with respect to fiber orientation, stress ratio, and thickness. The injection analysis was conducted using Moldflow software to obtain the information on fiber orientations. It was mapped over FEM concerned with fatigue specimens. LS-DYNA, a typical finite element commercial software, was used in the coupled analysis of Digimat to calculate the stress amplitude of composites. FEMFAT software consisting of various numerical material models was used to predict the fatigue life. The results of coupled analysis of linear and nonlinear material models of Digimat were analyzed to identify the fatigue characteristics of GFRP composites using FEMFAT. Neuber’s rule was applied to the linear material model to analyze the fatigue behavior in LCF regimen. Additionally, to evaluate the morphological and mechanical structure of GFRP composites, the coupled and fatigue analysis were conducted in terms of thickness.

Building Information Modeling (BIM) tools have not only increased the use of technology in the design process, but also increased the need for more information standard systems. The object classification system consists of 327 types of construction results obtained from 25 kinds of facilities, 174 types of parts, and 207 types of construction parts. In the previous study, the property classification system was developed into 4 major classifications, 13 middle classifications, 58 small classifications (category), and 333 attribution information of roads and rivers. It is extremely difficult to input the property information according to such extensive object classification. In addition, the development of external applications such as Revit plug-ins has created a need to automate specific and repetitive tasks. Therefore, following the BIM property classification system, an attribute input program was implemented for the system to enhance the productivity and convenience of the BIM users.

In this study, system modeling and dynamic analysis of crane are conducted. Especially, among many different kinds of a crane system, the issues on crane operating problems installed on the vessel are considered. As well known, marine systems including cranes are exposed to various disturbances such as vessel motions, hydrodynamic forces, wave and wind attack, etc. In order to analysis the system dynamic with environmental conditions, the authors derived the nonlinear dynamic model of offshore crane and derived a linear model which is used for designing the control system. Using the obtained nonlinear and linear models, simulations were conducted to evaluate the usefulness of the obtained models. By simulation and result evaluation, the usefulness of the linear model, which presents the dynamics, is effectively verified.