• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.67 no.1
• /
• pp.75-81
• /
• 2018

In this study, the simulation of partial discharge pulse waveform have been performed for the typical joints such as EBA and PMJ in the HV underground transmission XLPE cable system in order to improve the understanding of partial discharge pulse waveform and the on-site measurement accuracy of partial discharges. FDTD simulation technique was adopted for the simulation and has been shown to be suitable for partial discharge simulation of power cables in terms of pulse propagation characteristics and waveform formation. The simulation results for the EBA showed that the second not-so-large opposite polarity peak appeared after the first negative polarity peak and the measurement sensitivity was the highest near the bottom of the EBA copper box. In the analysis results for PMJ, the magnitude of the second opposite polarity peak was large enough to compare with the first peak, and the measurement sensitivity at the end of the PMJ copper box was the highest. These simulation results show considerable similarity with the on-site measurement, and it would be very useful for the partial discharge measurement of HV XLPE cable systems.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
• /
• 2003.04a
• /
• pp.352-361
• /
• 2003

A fatigue damage accumulation model based on the continuum damage mechanics theory was develope(1 where modules decay ratios in tension and shear on used as indicators for damage variables D . In the model, the damage variables are considered to be second-order tensors. Then the maximum principal damage variable, $D^*$ is introduced According to the similarity to the Principal stress, $D^*$ is obtained as the maximum eigen value of damage tensor [D']. Under proportional tension and torsion loadings, fatigue lives were satisfactorily predicted at any combined stress ratios using the present model in which the fatigue characteristics only under uniaxial tension and pure torsion loadings on needed. Fatigue life prediction under uniaxial tension and pure torsion loadings, was performed based on the damage mechanics using boundary element method.

• Transactions of the Korean Society of Machine Tool Engineers
• /
• v.13 no.6
• /
• pp.64-73
• /
• 2004

A fatigue damage accumulation model based on the continuum damage mechanics theory was developed where modulus decay ratios in tension and shear were used as indicators for damage variables D. In the model, the damage variables are considered to be second-order tensors. Then, the maximum principal damage variable, $D^*$ is introduced. According to the similarity to the principal stress, $D^*$ is obtained as the maximum eigen value of damage tensor [D]. Under proportional tension and torsion loadings, fatigue lives were satisfactorily predicted at any combined stress ratios using the present model in which the Fatigue characteristics only under uniaxial tension and pure torsion loadings were needed. Fatigue life prediction under uniaxial tension and pure torsion loadings, was performed based on the damage mechanics using boundary element method.

• Architectural research
• /
• v.16 no.4
• /
• pp.175-183
• /
• 2014

Contemporary architecture tends to deconstruct modern architecture based on rationalization just like reductionism and functionalism and secedes from it. It means change from mechanical to organic and ecological view of the world. According to these changes, consideration of a compositive relationship presented variety and complexity in architecture. Thus, the modern speculation based on rationalism cannot provide an alternative interpretation about complicated architectural phenomena. At this point in time, the purpose of this study is to investigate the possibilities of the fractal as an alternative tool of analysis and design in contemporary architecture. In this study, two major aspects are discussed. First, the fractal concepts just like 'fractal dimension', 'box-counting dimension' and 'fractal rhythm' can be applied to analysis in architecture. Second, the fractal formative principles just like 'scaling', 'superimposition trace', 'distortion' and 'repetition' can be applied to design in architecture. Fractal geometry similar to nature's patterned order can provide endless possibilities for analysis and design in architecture. Therefore further study of fractal geometry should be conducted synthetically from now on.

• Journal of the Korean Society of Industry Convergence
• /
• v.8 no.3
• /
• pp.143-148
• /
• 2005

This paper presents a hybrid method for recognizing the faces by using principal component analysis(PCA) and fixed-point independent component analysis(FP-ICA). PCA is used to whiten the data, which reduces the effects of second-order statistics to the nonlinearities. FP-ICA is applied to extract the statistically independent features of face image. The proposed method has been applied to the problems for recognizing the 20 face images(10 persons * 2 scenes) of 324*243 pixels from Yale face database. The 3 distances such as city-block, Euclidean, negative angle are used as measures when match the probe images to the nearest gallery images. The experimental results show that the proposed method has a superior recognition performances(speed, rate). The negative angle has been relatively achieved more an accurate similarity than city-block or Euclidean.

• Journal of Information Technology Services
• /
• v.7 no.4
• /
• pp.199-208
• /
• 2008

Tagging represents one of the Web 2.0 technology, and has an appropriate mechanism for the classification of dynamically changing Web informations. This technique is capable of searching the Web informations using the user specified tags, but still it has a limitation of providing only the limited informations to the tags. Therefore, in order to search the related informations easily, we need to extend this technique further to search not only the desired informations through the designated tags and also the related informations. In this paper, we first have designed and developed an algorithm that can get a desired tag cluster, which is capable of collecting the searched tags along with the related tags. We first performed a test to compare the difference between the user collected tag data through RSS and the reduced data. The second test focused on the accuracy of extracted related tags that depends on the similarity functions, such as the Pearson Correlation and Euclidean. Finally, we showed the final results visually using the graph algorithm.

• Korean Journal of Comparative Education
• /
• v.26 no.4
• /
• pp.153-172
• /
• 2016

This study aims at comparing and analyzing early childhood education systems in both South and North Koreas and suggesting educational alternatives for integrating in various aspects based on it, in order to build directions of early childhood education system in the preparation of Unification. A comparative study on the early childhood education system in South and North Korea was done in terms of early childhood education, public education of early childhood. As a result, there were differences rather than similarities in many areas due to the differences of political ideology between the South and the North. First, early childhood is not compulsory, but becomes public in South, while it is partially compulsory and has an overall public system in North in terms of its compulsory education and Pulic education. Second, as a result of comparing operating systems depending on early childhood education institutions in the South and North, there were differences in various areas such as subjects of foundation, classification of age, operating types, etc. Third, looking at its administrative support system, two Koreas has a similarity of a overall dual system, but showed a specific difference. Fourth, its public support had a similarity that early childhood education is done free of charge in two Koreas. In light of the results of comparing the early childhood education system in South and North Korea, this study suggests the following implications. First, as part of an effort to restore similarities of the early childhood education system between two Koreas, a challenge that must be addressed with priority is to integrate early childhood education-nursery in the early childhood education for age 3-5. Second, we'll take an effort to include the early childhood education for age 3-5 in the basic disciplines with 'Making early childhood education public' being currently focused. In addition, we should an attitude to recover a similarity through mutual exchange and to have advantages of the early childhood education in two Koreas as a challenge of taking an effort to integrate the early childhood education in the South and the North various studies and debates, discussions will be made for the meaning of the early childhood education and the integration.

• Proceedings of the Korea Inteligent Information System Society Conference
• /
• 2001.01a
• /
• pp.292-297
• /
• 2001

In writing learning as a second/foreign language, a learner has to acquire not only lexical and syntactical knowledge but also the skills to choose suitable words for content which s/he is interested in. A learning system should extrapolate learner\\`s intention and give example phrases that concern with the content in order to support this on the system. However, a learner cannot always represent a content of his/her desired phrase as inputs to the system. Therefore, the system should be equipped with a diagnosis function for learner\\`s intention. Additionally, a system also should be equipped with an analysis function to score similarity between learner\\`s intention and phrases which is stored in the system on both syntactic and idiomatic level in order to present appropriate example phrases to a learner. In this paper, we propose architecture of an interactive support method for English writing learning which is based an analogical search technique of sample phrases from corpora. Our system can show a candidate of variation/next phrases to write and an analogous sentence that a learner wants to represents from corpora.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
• /
• v.34 no.2
• /
• pp.161-169
• /
• 2016

This paper is intended to propose a novel approach to select an optimal site for a small-scaled artificial recharge system installation using TOPSIS (Technique for Order Preference by Similarity to Ideal Solution) with geospatial data. TOPSIS is a MCDM (Multi-Criteria Decision Making) method to choose the preferred one of derived alternatives by calculating the relative closeness to an ideal solution. For applying TOPSIS, in the first, the topographic shape representing optimal recovery efficiency is defined based on a hydraulic model experiment, and then an appropriate surface slope is determined for the security of a self-purification capability with DEM (Digital Elevation Model). In the second phase, the candidate areas are extracted from an alluvial map through a morphology operation, because local alluvium with a lengthy and narrow shape could be satisfied with a primary condition for the optimal site. Thirdly, a shape file over all candidate areas was generated and criteria and their values were assigned according to hydrogeologic attributes. Finally, TOPSIS algorithm was applied to a shape file to place the order preference of candidate sites.

• Journal of Korea Multimedia Society
• /
• v.24 no.3
• /
• pp.416-422
• /
• 2021

Due to the large differences in human activity within classes, the large similarity between classes, and the problems of visual angle and occlusion, it is difficult to extract features manually, and the detection rate of human behavior is low. In order to better solve these problems, an improved Faster R-CNN-based detection algorithm is proposed in this paper. It achieves multi-object recognition and localization through a second-order detection network, and replaces the original feature extraction module with Dense-Net, which can fuse multi-level feature information, increase network depth and avoid disappearance of network gradients. Meanwhile, the proposal merging strategy is improved with Soft-NMS, where an attenuation function is designed to replace the conventional NMS algorithm, thereby avoiding missed detection of adjacent or overlapping objects, and enhancing the network detection accuracy under multiple objects. During the experiment, the improved Faster R-CNN method in this article has 84.7% target detection result, which is improved compared to other methods, which proves that the target recognition method has significant advantages and potential.