선박의 주묘 위험성을 평가할 수 있는 프로그램이 개발되어 있지만 선박의 제원에 해당되는 다양한 입력요소들을 직접 찾아서 입력해야 하므로 VTS 관제사가 정박지에 정박 중인 선박들로부터 이러한 입력요소들을 모두 확인하여 프로그램을 활용하는 것은 현실적으로 어려운 상황이다. 이에 본 연구에서는 VTS 관제사 입장에서 선박으로부터 쉽게 획득할 수 있는 총톤수(GT)를 독립변수로 설정하고 프로그램 입력요소들을 종속변수로 하여 선형 및 비선형 회귀분석을 실시하였다. 다항식 모델(선형)과 멱급수 모델(비선형)의 적합도를 비교한 결과, 컨테이너선과 벌크선의 경우에는 모든 입력요소에서 멱수급 모델이 적합한 것으로 평가되었다. 하지만 탱커선의 경우에는 수선간장, 선폭, 흘수는 멱수급 모델이 적합하고, 정면풍압면적, 앵커의 무게, 의장수, 묘쇄공으로부터 선저까지의 높이는 다항식 모델이 더 적합한 것으로 평가되었다. 또한 탱커선의 정면풍압면적 요소를 제외한 다른 나머지 종속변수들은 모두 결정계수가 0.7 이상으로 높은 적합도를 보였다. 따라서 주묘 위험성 평가 프로그램의 입력요소 중 외력 요소, 해저 저질, 수심 및 앵커 체인의 신출량을 제외한 나머지 입력요소들은 선박의 총톤수만 입력하면 회귀분석 모델식에 의해 자동으로 입력됨으로써 주묘 위험성 평가가 가능할 것으로 판단된다.

PURPOSES : The purpose of this study is to evaluate the road design elements affecting the lateral driving safety under high-speed driving conditions with a speed limit of 140 km/h and to derive useful implications to design of safer roads. METHODS : A full-scale driving simulator was used to evaluate the various design scenarios. Different regression techniques and a random forest method were adopted to conduct comprehensive comparisons among the simulation scenarios. The relationships between the safety indicators, including the frequency of the lane departures and the standard deviation of the lateral acceleration, and the design elements were explored in terms of lateral driving safety. RESULTS : The length of the combined alignment was found to be a significant factor affecting the lateral driving safety based on the analysis of the frequency of lane departures. Regarding the standard deviation of the lateral acceleration, it was identified that the length of the horizontal curve, the length of the bridge, and the right-side superelevation must be considered significant factors associated with driving safety while designing the road under high-speed driving conditions. CONCLUSIONS : Based on the findings of this study, a set of recommendations for designing roads was proposed. For example, the proper length of the combined alignment and the horizontal curve should be determined to prevent crashes due to hazardous lateral driving events because the installation of sufficient superelevation in the bridge section would be limited under high-speed driving conditions. In addition, applying a larger horizontal curve radius with longitudinal grooving is a promising approach to tackle risky driving conditions.

In the event of an earthquake, non-structural components require seismic performance to ensure evacuation routes and to protect lives from falling non-structural components. Accordingly, the seismic design code proposes horizontal force for the design and evaluation of non-structural components. Ground motion observed on each floor is affected by a building's eigen vibration mode. Therefore, the earthquake damage of non-structural components is determined by the characteristics of the non-structural component system and the vibration characteristics of the building. Floor response spectra in the seismic design code are estimated through time history analysis using seismic waves. However, it is difficult to use floor response spectra as a design criterion because of user-specific uncertainties of time history analysis. In addition, considering the response characteristics of high-rise buildings to long-period ground motions, the safety factor of the proposed horizontal force may be low. Therefore, this study carried out the horizontal force review proposed in the seismic design code through dynamic analysis and evaluated the floor response of seismic waves considering buildings and predominant periods of seismic waves.

Tomb of King Muryeong, located in Sonsan-ri, was found vulnerable due to leakages during since the summer of 2016. This research aims to evaluate structural safety of the Tomb under the tumulus. Site surveys were conducted to find vulnerable inner parts. Structural safety assessment is presented based on both site survey results and analytical results obtained through FEM analysis using the ANSYS program. The underground structure was explicitly modeled to focus on two types of loadings: design loads and actual gravity loads. In general, the tomb does not show any critical deflection increase or damage through the analytical investigation. However, maintenance through continuous monitoring is necessary to prevent severe deflections and stress concentrations since the rigidity of the tomb materials are very vulnerable and likely to be reduced due to prolonged weathering and continuous rain leakage.

본 논문에서는 유한요소해석을 이용하여 흉요추 후방 고정술의 고정분절 변화에 따른 척추 안정성을 평가하였다. 이를 위해 추간판, 인대, 추간관절(Facet joint) 등을 포함한 정상 흉요추(T10–L4)의 유한요소모델을 구축하였으며, 문헌으로 보고된 재료물성치를 부여하였다. 한편, L1을 병변 부위로 가정하였으며, L1-L2, T12-L2, T12-L1-L2 총 3가지 종류의 후방 고정술을 흉요추 유한요소모델에 구현하고 전방 굽힘, 후방 굽힘, 측면 굽힘, 축 회전의 하중 조건을 부여하였다. 시리즈 유한요소해석을 통해 고정분절에 따른 척추경 나사못, 척추골, 추간판의 변형량, 등가 응력, 운동 범위, 모멘트를 계산하였으며, 그 결과를 바탕으로 척추 안정성을 평가하였다.

Recent earthquakes in Korea caused some damages to stone pagodas and thereby awakened the importance of earthquake preparedness. Korean stone pagodas which have been built with very creative style of material use and construction method are worthy of world heritage. Each stone pagoda consists of three parts: top; body; and base. However each tower is uniquely defined by its own features, which makes it more difficult to generalize the seismic assessment method for stone pagodas. This study has focused on qualitative preliminary evaluation of stone pagodas that enables us to compare the relative seismic performance across major aspects among many various Korean pagodas. Specifically an analytical model for multi-block stone pagodas is to be proposed upon the investigation of structural characteristics of stone pagoda and their dynamic behavior. A strategy for seismic evaluation of heritage stone pagodas is to be established and major evaluation factors appropriate for the qualitative evaluation are identified. The evaluation factors for overall seismic resisting behavior of stone pagodas are selected based on the dynamic motions of a rigid block and its limit state. Numerical simulation analysis using discrete element method is performed to analyze the sensitivity of each factor to earthquake and discuss some effects on seismic performance.

최근 국내에서는 고층 벽식 아파트 건설 시, 하부 주차공간과 공용공간 확보를 위하여 RC 전이슬래브 시스템을 사용하는 경우가 증가하고 있다. 하지만 두께가 얇은 RC 무량판 슬래브를 위해 개발된 설계방법 및 구조성능평가 방법을 두께가 매우 두꺼운 전이슬래브 구조설계에 그대로 사용하고 있다는 문제점이 있다. 따라서 합리적인 전이슬래브의 구조설계를 위해서는 RC 전이슬래브 시스템의 2면 전단거동 양상에 대한 명확한 분석이 필요하다. 이에 따라 본 연구에서는 전이슬래브의 두께, 콘크리트 강도, 전단경간비, 철근비 등 다양한 설계변수에 따라 비선형 FEM을 이용하여 전이슬래브의 2면 전단거동을 분석 하였다. 또한 비선형 FEM 해석결과와 기존의 2면 전단강도 평가식으로 예측한 전단강도를 비교분석하여 기존 평가식의 전이슬래브 2면 전단강도 평가 유효성을 검토하였다.

본 연구는 게임 관련 전문가 23명에게 델파이 기법을 사용해 기존의 게임 가치평가에 추가적 요소들을 추출해 보고자 한다. 기존에 제시된 게임 컨텐츠의 평가 모델을 이용하여 개발 모델의 특성을 전반적으로 검토 한 결과, 컨텐츠를 선정 할 때 가치 평가 요소가 선정되었음을 알 수 있었으며 델파이 분석은 2차에 걸쳐서 이루어졌으며, 1차는 전문가 FGI, 2차는 델파이 설문으로 진행되었다. 결과, 기술 이전 및 보급, 상용화 촉진을 위한 세부 내용 등 관련 항목등에서 보다 세밀한 요소들이 제시되었다. 포커스 그룹 인터뷰를 통해 추가 요인을 추출하고 게임 업계의 컨텐츠 성공에 대한 시장 분석을 통해 시장 규모, 성장 잠재력, 규제 및 시장 매력과 위험을 예측 했으며 이를 통해 관련 업계는 성공 목표에 대한 시장 분석을 통해 시장 규모, 성장 잠재력, 규제, 시장 호소력 및 위험성을 이해할 수 있을 것으로 기대한다. 이 연구는 제안 된 평가 요소가 게임 및 문화 콘텐츠 산업 전 체에 적용될 수 있음을 시사하며 또한 콘텐츠의 시장 가치 평가, 목적 및 목표 설정, 진입 방법 선택, 전략 요소 등 시장 요인을 구성하는 것에 도움이 될 것이다.

In this paper, we analyzed the safety on static and dynamic characteristics of a top-down evacuation instrument fixed on the exterior walls of a building using finite element analysis. For this purpose, the stress distribution characteristics of the H-beam structure were analyzed and the equivalent stress distribution, deflection displacement and natural frequency characteristics of the overall structure of the evacuation instrument were analyzed. The structures were applied with the materials of SS440 and SUS304. The static analysis results showed the elastic behavior with safety coefficients from 2.4 to 2.9, by confirming the structural safety. In addition, the analysis of the natural frequency characteristics confirmed that the vibration characteristics were higher than the external conditions of 20Hz.

본 연구에서는 옹벽 구조물의 내진성능 평가를 위해 2차원 유한요소 해석을 수행하였다. 2차원 유한요소 모델은 실제로 시공된 옹벽 구조를 기반으로 2차원 평면변형 요소로 모델링되었으며, 지반은 각각 유한요소와 무한요소로 모델링 하였다. 지진하중은 총 38개의 인공 지진을 생성하여 사용하였고, 생성된 인공 지진파를 11개의 PGA로 나누어 총 418회의 시간이력해석을 수행하였다. 수치해석 결과를 바탕으로 옹벽 구조물의 지진에 대한 취약도를 분석하였다. 취약도 분석 결과 콘크리트 및 철근의 취약도 곡선이 낮은 PGA 수준에서 급격히 변하는 것을 관찰할 수 있었다. 유한요소 해석 결과를 바탕으로 실제 현장의 옹벽 구조에서 상대적으로 낮은 수준의 지진파가 발생하더라도 높은 파괴확률로 인해 지진에 상대적으로 취약함을 확인하였다.

In this study, finite element (FE) analysis was performed to evaluate the seismic performance of the water treatment plant, which is a major state of the art water treatment plant, to predict tensile cracks and compressive failure. The FE model simulation for two facilities of the water purification plant was made considering the initial conditions, boundary conditions and water effect. For the nonlinear dynamic analysis, seismic analysis was performed using ground acceleration. Tensile cracks and compressive failure are analyzed and the effects on the structures are analyzed. As a result of the analysis, tensile cracks can be predicted to occur in the main structure.

In the international businesses human resource elements acquired in different countries might have different values in varied industries due to the different quality of education and experiences in the original countries. Using selection models to evaluate expected values in earnings equation of human resource elements such as education and experiences etc. acquired in sending countries, system equations are expanded to examine also the values of science and engineering degrees in technology jobs with selectivity bias correction. This paper used the US census survey data of 2015 on earnings, academic degrees, occupations etc. The US has long maintained the policy of accepting more STEM workers than any other countries and helped maintaining own technological leadership. Assuming per capita GDP gap between the sending country and the US downgrades immigrant human resource quality, it rarely affects occupational selection but depresses earnings on average by two or more years’ worth of education. Immigrant quality index in the sense of GDP gap appears to be a valid tool to assess the expected earnings of the worker with. Engineering degrees increase significantly the probability of selecting not only engineering jobs but also general management jobs, as well as increasing the expected earning additionally over nine years’worth of education. Getting a technology job is additionally worth about four years of education. Economics and business degrees are worth additionally almost six years of education but humanities degrees depress expected earnings. Since years after immigration does not very fast enhance earnings capacity, education level and English language ability might be more useful criteria to expect better future earnings by.

PURPOSES: This study aims to evaluate the effects of vehicle dynamic behaviors on ride quality. METHODS: Simulation and field test were conducted to analyze the behavior of a driving vehicle. The simulation program CarSIM was applied and an INS (Inertial Navigation System) was used for field experiments. A small simulator was developed to simulate vehicle behavior such as roll, pitch, and bounce. The panels evaluated the ride quality in five stages from “very satisfied”to “very dissatisfied.”Experiments were conducted on a total of 144 cases of vehicle behavior combinations. RESULTS: In both simulation and field tests, pitch is the largest and yaw the smallest. Especially in the field test, the amount of yaw is very low, about 7% of pitch and 18% of roll. The sensitive and extensive analysis conducted related ride quality with changing the frequency and amplitude. It was found that the most sensitive frequency range is 8 Hz across all amplitudes. Moreover, the combination of the roll and bounce was most sensitive to the ride quality at the low-frequency range. CONCLUSIONS: This result show that the vertical vehicle behavior (bounce) as well as the rotational behavior (roll and pitch) are highly correlated with ride quality. Therefore, it is expected that a more reasonable roughness index can be developed through a combination of vertical and rotational vehicle behavior.

In international businesses human resource elements acquired in different countries might have different values in varied industries due to different quality of education and experiences in original countries. Using existing models to evaluate expected values of human resource elements such as education and experience setc. acquired in sending countries they are expanded to examine also the values of science and engineering degrees in technology jobs with selectivity bias correction. This paper used the US census survey data of 2015 on earnings, academic degrees etc. to contrast qualitative effects with quantitative effects of human resource elements compared to those in the native and/or white group.

This study performs finite Element stress analysis of flange connections at noise barriers with circular steel tubes, which have a light weight. Subsequent numerical simulation results for three types of models (standard, double, and standard models strengthen by ribs) present that the applied connections for target noise barriers constructed show suitable structural performance. In this paper, the existing finite element stress analysis using the ABAQUS program is further extended to study the local stress distribution of the noise barriers with new type circular steel tubes. The numerical results for various parameters are verified by comparing different types with stresses occurred in the noise barrier from the numerical simulation.

본 논문에서는 고차미분 연속성을 가지는 형상함수에 기초하여 오일러-베르누이 보 유한요소모델을 정식화하였으며, 다 양한 경계조건들에 대하여 그 성능을 평가하였다. 이러한 유한요소 모델들은 새로이 개발되는 고차 보 이론들과 논로컬 탄 성이론에 기초한 보 이론들의 유한요소해석에 필요하다. 그러나 고차 연속성을 가지는 유한요소에 대한 성능평가는 문헌에 서 찾아보기 어렵다. 따라서 본 연구에서는 C2 및 C3 두 종류의 고차 유한요소들을 정식화하여 외팔보, 단순지지, 고정-힌 지 등의 경계조건들을 적용하고 정적해석을 수행하였다. 고전적인 경계조건들 이외에도 고차 경계조건들이 보의 거동에 미 치는 영향을 비교분석하였다. 경계조건에 따라서는 처짐의 미분 값들이 경계주변에서 진동하는 현상이 관찰되었으며, 이는 기하학적 경계조건들에 대하여 뚜렷이 나타난다. 특히 고정단과 같은 경계에서의 변위의 고차미분 조건은 이러한 불안정한 현상을 유발한다. 본 연구에서 얻어진 결과들은 고차 미분 연속성을 가지는 유한요소 이용에 가이드라인으로서 역할을 할 수 있을 것으로 기대된다.