• Computational Structural Engineering
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• v.3 no.3
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• pp.113-123
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• 1990

The paper is concerned with the elasto-plastic and geometrically nonlinear analysis of shell structures using an improved degenerated shell element. In the formulation of the element stiffness, the combined use of three different techniques was made. They are; 1) an enhanced interpolation of transverse shear strains in the natural coordinate system to overcome the shear locking problem ; 2) the reduced integration technique in in-plane strains to avoid the membrane locking behavior ; and 3) selective addition of the nonconforming displacement modes to improve the element performances. This element is free of serious shear/membrane locking problems and undesirable compatible/commutable spurious kinematic deformation modes. In the formulation for plastic deformation, the concept of a layered element model is used and the material is assumed von Mises yield criterion. An incremental total Lagrangian formulation is presented which allows the calculation of arbitrarily large displacements and rotations. The resulting non-linear equilibrium equations are solved by the Netwon-Raphson method combined with load or displacement increment. The versatility and accuracy of this improved degenerated shell element are demonstrated by solving several numerical examples.

• Journal of Astronomy and Space Sciences
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• v.24 no.4
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• pp.269-274
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• 2007

We established a regional ionospheric model for investigating ionospheric TEC (Total Electron Contents) variations over the Korean Peninsula during major geomagnetic storms. In order to monitor the ionospheric TEC variations, we used nine permanent GPS reference stations uniformly distributed in South Korea operated by the Korea Astronomy and Space Science Institute (KASI). The cubic spline smoothing (CSS) interpolation method was used to analyze the characteristics of the ionospheric TEC variations. It has been found that variations of TEC over the Korean Peninsula increase when a major geomagnetic storm occurred on November 20, 2003. The TEC has increased about one and a half of those averaged quite days at the specific time during a geomagnetic storm. It has been indicated that the KASI GPS-derived TEC has a correlation with the geomagnetic storm indices (eq. Kp and Dst indices).

• Proceedings of the KIEE Conference
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• 2008.10b
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• pp.262-263
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• 2008

LCD 디바이스는 그 동작원리와 전기-광학적 특성에 의해 CRT와는 다른 감마곡선 특성을 갖고 있다. 대부분의 LCD디스플레이 디바이스들의 감마곡선은 CRT와는 달리 일관성을 갖지 않을 뿐 더러 흑백계조입력을 기준으로 하는 감마보정을 위해 RED, GREEN, BLUE 입력값을 세부적으로 조정할 때 각 계조입력에 대한 상관색온도가 일정한 값을 갖지 않아 LCD의 특성에 대한 모델링과 보정에 어려움이 있다. 또한, 애플사의 맥머신 그리고 실리콘 그래픽스사의 시스템과 같이 소정의 감마값을 전제로 해당 시스템의 내부참조테이블(internal look-up table)이 설계되어 각기 다른 시스템감마를 가지는 장치들에 의해 인코딩되어진 영상출력신호의 경우, 동일한 시스템을 갖추거나 시스템감마에 대한 역감마특성을 가진 디스플레이장치가 아닌 환경에서는 원본영상에 대한 왜곡은 더욱 커질 수 있다. 특히, 낮은 흑백계조입력에서의 색온도의 경우, 파장에 따라 서로 다른 감쇄성능을 가진 일반적인 컬러필터의 특성에 의한 누설광(light leakage)에 의해 결정되며, 이로 인해 색온도가 특정한 객을 띄는 현상이 발생한다. 본 논문에서는 LCD디스플레이의 감마곡선을 여러 가지 시스템감마에 대응할 수 있는 감마곡선예 일치시키고, 계조선형성을 동시에 개선하기 위하여 입력 디지털값과 삼자극치간 관계를 나타내는 여러 가지 컬러모델링 방법 중에서 PLCC(Piecewise Linear Interpolation assuming Constant Chromaticity coordinates)모델을 적용하고, 목표로 하는 감마곡선과 색온도를 만족하기 위한 새로운 입력값을 구한 후 이를 컬러참조테이블(color look-up table)예 적용하는 방법과 저계조에서의 색온도를 목표색온도에 근접시키는 방법을 제안한다.

• Atmosphere
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• v.25 no.2
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• pp.271-281
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• 2015

The objectives of this study are to develop a hydrological drought outlook system using GloSea5 (Global Seasonal forecasting system 5) which has recently been used by KMA (Korea Meteorological Association) and to evaluate the forecasting capability. For drought analysis, the bilinear interpolation method was applied to spatially downscale the low-resolution outputs of GloSea5 and PR (Predicted Runoff) was produced for different lead times (i.e., 1-, 2-, 3-month) running LSM (Land Surface Model). The behavior of PR anomaly was similar to that of HR (Historical Runoff) and the estimated values were negative up to lead times of 1- and 2-month. For the evaluation of drought outlook, SRI (Standardized Runoff Index) was selected and PR_SRI estimated using PR. ROC score was 0.83, 0.71, 0.60 for 1-, 2- and 3-month lead times, respectively. It also showed the hit rate is high and false alarm rate is low as shorter lead time. The temporal Correlation Coefficient (CC) was 0.82, 0.60, 0.31 and Root Mean Square Error (RMSE) was 0.52, 0.86, 1.20 for 1-, 2-, 3-month lead time, respectively. The accuracy of PR_SRI was high up to 1- and 2-month lead time on local regions except the Gyeonggi and Gangwon province. It can be concluded that GloSea5 has high applicability for hydrological drought outlook.

• Journal of Korea Society of Industrial Information Systems
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• v.23 no.1
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• pp.1-12
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• 2018

This paper presents a material estimation method using dual-energy X-ray images generated as a result of cargo inspection system in MeV region. We use new discrimination curve using logarithmic function rather than four discrimination curves commonly used in existing estimation algorithms. We also propose an atomic number estimation using the probability distribution of the logarithmic curve rather than linear interpolation. When the probability distribution is used as a weight, we used two methods of using the weight for the two nearest reference materials and the weight for all the reference materials. Experimental results showed that the atomic number estimation of materials using the probability distribution as a weight is more accurate than the existing methods. In order to visualize the estimated atomic number, the HSI model was used for color the resulting image.

• Journal of KIISE:Software and Applications
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• v.37 no.4
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• pp.297-304
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• 2010

Clustering method which based on sentence type or document genre is a technique used to improve translation quality of SMT(statistical machine translation) by domain-specific translation. But there is no previous research using sentence type and document genre information simultaneously. In this paper, we suggest an integrated clustering method that classifying sentence type by syntactic structure similarity and document genre by word similarity information. We interpolated domain-specific models from clusters with general models to improve translation quality of SMT system. Kernel function and cosine measures are applied to calculate structural similarity and word similarity. With these similarities, we used machine learning algorithms similar to K-means to clustering. In Japanese-English patent translation corpus, we got 2.5% point relative improvements of translation quality at optimal case.

• Journal of Korean Society for Atmospheric Environment
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• v.25 no.1
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• pp.15-25
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• 2009

Donghae city is one of the most representative cement industrial city in Korea. The area is faced with the East Sea to the East and with high montane region of Tae-Back mountain range to the West. Many pollutant sources of air pollution are located near the coast, but the largest point sources of the region are located at the bottom of the mountain area in Donghae city. The local wind is highly affected by local topography and plays an important role in transport and dispersion of contaminants from the pollution sources. This study was designed to evaluate enhancement of MM5 predictions by using Four Dimensional Data Assimilation (FDDA), the SONDE data and the national meteorological station, data only. The alternative meteorological fields predicted with and without FDDA were used to simulate spatial and temporal variations of NOx in combined with Atmospheric Dispersion Models (CALPUFF). For the modeling domain, the alternative meteorological fields with 1.1 km spatial resolution were interpolated to the CALMET with 0.5 km resolution. The vertical layers set to have 35 and 12 layers for MM5 and CALPUFF, respectively. MM5 with the FDDA did not resulted in significant improvement of meteorological field prediction in Donghae region, which is primarily because of complex geography and wind scheme. The result of CALPUFF, however, showed reduction of uncertainty errors by using the interpolation scheme of the actual measurement data.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• v.2
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• pp.143-147
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• 2006

The rail clamp is the device to prevent that a crane slips along rails due to the wind blast as well as locate the crane in the set position for loading and unloading containers. The wedge type rail clamp should be designed to consider the structural stability and the durability because it compresses both rail side with large clamping force by the wedge working as the wind speed increases. In this research, the kriging interpolation method using sequential sampling is utilized to find the optimum shape of the jaw in the rail clamp. The suggested method predicts more accurate response value than the response surface method. The optimum results obtained by the proposal method are compared with those by the commercial software.

• Spatial Information Research
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• v.19 no.5
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• pp.47-52
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• 2011

Recently damage scale by local winds and typhoon has dramatically increased. Korea has the terrain over 70% of the land and the planning of the wind load is necessary to estimate reflecting appropriately the change of the wind-speed according to the characteristic of the terrain and in the Korean Building Code(2009), this is stated and it reflects to the design process. However, in order to estimate the topographic factor of the wind speed considering the topographic characteristics in the structure design actually, it has many difficult points including the local topographic survey, etc. In this paper, the Digital Elevation Model(DEM) is created using TIN interpolation method in the form of the digital map and then the interface was designed and implemented which can automatically estimate the topographic factor of wind speed by using ESRI(R)ArcObjectTM and the Visual Basic programing language. By applying it to the terrain which positioned in the downtown area, the practicality of the topographic factor of wind speed estimation interface was checked.

• Journal of The Korean Association For Science Education
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• v.15 no.1
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• pp.92-103
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• 1995

Since the late of 1960,s, the improvement of science inquiry skills has been one of the most important goals in secondary science education. To achieve this goal, it is essential to develop a valid and reliable instrument for evaluating science inquiry skills. The purpose of this study is to develop a valid and reliable instrument for evaluating science inquiry skills for high school students. The instrument is developed through R & D procedure, which includes two field trials of the instrument. This study has formed a clear definition of the elements of science inquiry skills (formulating a hypothesis, controlling variables, designing an experiment, numeric calculation, graphing experimental data, inference, determining relationship, determining causalities, predicting experimental results , drawing a conclusion, formulating a generalization or model), and established the goals of assessment and developed the items of assessment. The instrument, Test of Earth Science Inquiry Skills, consists of 33 items which measure 11 science inquiry skills. There are content-free items for each science inquiry skills. This study has selected 11 science inquiry skills which are considered appropriate for being evaluated by paper-and-pencil test with SIEI (Hur,1984). The content validity of items, objectivity of the scoring keys and clarity of the items were checked by six experienced specialists in science education. At the same time, the two field trials has been executed and produced the reliability of the instrument, item difficulty index, and the effectiveness of distracters. The first field trial was performed using a sample of 304 high school students, and the second one using a sample of 872 high school students. Because the content validity is 84 % and the reliability (K-R 20) is 0.84, the developed instrument in this study is considered valid and reliable. The difficulty index is 49.4 %, answer ratio 59.1 %, the discrimination index 0.47 and the effectiveness of distracters evenly distributed, which also suffice the criteria of good instrument. The developed instrument in this study can diagnosis the well-developed science inquiry skills and the ill-developed science inquiry skills of the students, and trace the degree of the improvement of science inquiry skills.