• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2020.07a
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• pp.1-5
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• 2020

최근 MPEG-I 그룹에서는 표준화가 진행중인 몰입형 미디어(Immersive Media)에 대한 압축 성능 탐색이 이루어지고 있다. 몰입형 비디오는 다수의 시점 영상과 깊이 맵을 통한 깊이 맵 기반 이미지 렌더링(DIBR)을 바탕으로 제한적 6DoF 을 제공하고자 하는 기술이다. 현재 MIV(Model for Immersive Video) 기술에서는 바탕 시점(Basic View)과 각 시점의 고유한 영상 정보를 패치 단위로 모아둔 추가 시점(Additional View)으로 처리하는 모델을 채택하고 있다. 그 중에서 추가 시점은 일반적인 영상과는 달리 시간적/공간적 상관성이 떨어지는 분절적인 형태로 이루어져 있어 비디오 인코더에 대해 최적화가 되어 있지 않으며, 처리 방법의 특성에 따라 자기 유사적인 형태를 지니게 된다. 따라서 MIV 에서 스크린 콘텐츠 코딩 성능과 함께 화면 내 블록 카피(IBC: intra block copy) 기술에 대한 성능을 분석 결과를 제시한다. IBC 미적용 대비 최대 7.56%의 Y-PSNR BD-rate 감소가 가능함을 확인하였으며, 영상의 특성에 따라 IBC 의 선택 비율을 확인하여 추가 시점의 효율적인 압축 형태를 고찰한다.

• The KIPS Transactions:PartD
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• v.8D no.5
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• pp.507-512
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• 2001

Feature-based similarity has become an important research issue in multimedia database systems. The features of multimedia data are useful for discriminating between multimedia objects. the performance of conventional multidimensional data structures tends to deteriorate as the number of dimensions of feature vectors increase. The $R^{*}-Tree$ is the most successful variant of the R-Tree. In this paper, we propose a SOM-based $R^{*}-Tree$ as a new indexing method for high-dimensional feature vectors. The SOM-based $R^{*}-Tree$ combines SOM and $R^{*}-Tree$ to achieve search performance more scalable to high-dimensionalties. Self-Organizingf Maps (SOMs) provide mapping from high-dimensional feature vectors onto a two-dimensional space. The map is called a topological feature map, and preserves the mutual relationships (similarity) in the feature spaces of input data, clustering mutually similar feature vectors in neighboring nodes. Each node of the topological feature map holds a codebook vector. We experimentally compare the retrieval time cost of a SOM-based $R^{*}-Tree$ with of an SOM and $R^{*}-Tree$ using color feature vectors extracted from 40,000 images. The results show that the SOM-based $R^{*}-Tree$ outperform both the SOM and $R^{*}-Tree$ due to reduction of the number of nodes to build $R^{*}-Tree$ and retrieval time cost.

• Journal of Gifted/Talented Education
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• v.21 no.1
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• pp.107-122
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• 2011

The purpose of this study is to explore the perception of the observation and nomination system for the identification of the gifted and to find out the importance and practice level perceived by the gifted education teachers using the concept mapping approach. For this, twelve gifted education teachers brainstormed and gathered ideas for the ideal ways of observation and nomination system and the gathered statements were solicited. Multidimensional scaling and hierarchical cluster analysis were also used. In addition, 112 gifted education teachers rated the importance of and the practice level for the suggested ideas of observation and nomination system. Results were as follows: First, 36 statements were solicited and as a result of concept mapping the suggested observation and nomination system were categorized as 'attainment of professionality', 'attainment of administrative support', 'attainment of fairness', and 'considering points for recommendation.' Second, there were significant differences between the perceived importance levels and the practice levels. Based on the results, imlications of the study were discussed in depth.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.7
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• pp.258-264
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• 2018

This paper presents application of a differential search (DS) meta-heuristic optimization algorithm for optimal operation of a micro grid system. The DS algorithm simulates the Brownian-like random-walk movement used by an organism to migrate. The micro grid system consists of a wind turbine, a diesel generator, a fuel cell, and a photovoltaic system. The wind turbine generator is modeled by considering the characteristics of variable output. Optimization is aimed at minimizing the cost function of the system, including fuel costs and maximizing fuel efficiency to generate electric power. The simulation was applied to a micro grid system only. This study applies the DS algorithm with excellence and efficiency in terms of coding simplicity, fast convergence speed, and accuracy in the optimal operation of micro grids based on renewable energy resources, and we compared its optimum value to other algorithms to prove its superiority.

• Korean Journal of Environment and Ecology
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• v.34 no.5
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• pp.436-445
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• 2020

The number of protected areas has been steadily increased in Korea to achieve Aichi Target 11, and there are studies on potential protected areas that required additional designation. However, there has been an insufficient assessment of the complementarity of protected areas to conserve biodiversity effectively. This study identified the potential habitat areas using the species distribution model for plant species from the 3rd National Ecosystem Survey and compared the plant species abundance in the existing protected area and the potential protected areas using the similarity indices, such as the Jaccard index, Sorenson index, and Bray-Curtis index. As a result, we found that the complementarity of the existing protected areas and most potential protected areas were low, leading to the preservation of similar plant species. Only the buffer zone for Korea National Arboretum had high complementarity and thus is important to conserve some species with the other protected areas. This study confirmed that it was necessary to select additional protected areas outside the existing or potential protected areas to protect plant species with a low inclusion ratio of potential habitats within the protected area. This study is significant because it identified the ecological representativeness of each protected area to examine if the individual protected area can conserve unique and various species and proposed a method of finding candidate areas for additional conservation spatially. The findings of this study can be a valuable reference for the qualitative improvement of protected areas through the complementarity assessments, including animals and the effectiveness assessment study of protected areas using the National Ecosystem Survey data in the future.

• The Journal of the Korea Contents Association
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• v.21 no.7
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• pp.1-12
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• 2021

This study explored the mechanism by which stars and fans build a global fandom community based on social connectivity of social media based on BTS' official Twitter and in-depth interviews with Chinese, American, and Korean fans. Stars and fans use the connectivity of social media to build a pseudo-private relationship that crosses public and private affairs. Even though they won the award, BTS "congratulates" the fan club, ARMY, and organizes a dialogue method so that each fan becomes the subject. From a fan's point of view, it comes to be seen as a personal message to them, which is not just applied to the text composition method. On days when there is no public message such as official activities or anniversaries, a device to communicate without missing a day has been prepared by raising private messages or previous memories. It was found that the sense of constant connection strengthens fans' sense of community toward each other.

• Journal of the Korean Society for information Management
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• v.23 no.2
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• pp.61-79
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• 2006

To come up with the recommendations to improve the patent & trademark retrieval efficiency, 100,016 patent & trademark search requests by 17,559 unique users over a period of 193 days were analyzed. By analyzing 2,202 multi-query sessions, where one user issuing two or more queries consecutively, we discovered a number of retrieval efficiency improvements clues. The session analysis result also led to suggestions for new system features to help users reformulating queries. The patent & trademark retrieval users were found to be similar to the typical web users in certain aspects especially in issuing short queries. However, we also found that the patent & trademark retrieval users used Boolean operators more than the typical web search users. By analyzing the multi-query sessions, we found that the users had five intentions in reformulating queries such as paraphrasing, specialization, generalization, alternation, and interruption, which were also used by the web search engine users.

• Tunnel and Underground Space
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• v.18 no.3
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• pp.194-201
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• 2008

In order to investigate the characteristics in tensile strength of transversely isotropic rock, a new anisotropic tensile failure function was suggested. According to the function, the tensile strength is minimum in the normal direction to a weakness plane and rises exponentially to its maximum on a plane perpendicular to the weakness plane. The anisotropic function is defined in terms of three strength parameters which can be identified trom direct tensile tests of transversely isotropic rocks. By incorporating the suggested function into the critical plane approach, a numerical procedure which enables to search the tensile strength and the direction of critical plane at failure was presented. The validity of the suggested numerical procedure was checked through the simulation of direct tensile tests reported in a literature. The numerical results from the simulation were in good agreements with those from the laboratory tests.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.4
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• pp.413-418
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• 2021

Nano-materials with high effective surface areas have been applied to functional materials, such as high sensitive gas sensors and biosensors and high-efficiency catalytic materials. In this study, titanate sheets with a 3D nano-wall-like structure, high effective surface area, were synthesized vertically to the substrate by a chemical bath deposition (CBD) process using a Ti sheet and urea. The synthesis temperature and synthesis duration time were controlled to the optimal conditions of a 3D nano-wall-like structure in the CBD process. The synthesized ammonium titanate sheets with a 3D nano-wall-like structure were annealed in air to transform to TiO2 with a 3D nano-wall-like structure for various applications. As a result, the optimal temperature in the CBD process for the synthesis of a uniform ammonium titanate sheet with a 3D nano-wall-like structure was 90 ℃. TiO2 with a 3D nano-wall-like structure was obtained from the ammonium titanate sheet with a 3D nano-wall-like structure by annealing above 550 ℃ for three hours. In particular, TiO2 with a 3D nano-wall-like structure with a dominant rutile phase was obtained by post-annealing at 700 ℃. On the other hand, damage to the 3D nano-wall edge was observed after 700 ℃ post-annealing.

• Korean Journal of Ichthyology
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• v.19 no.4
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• pp.257-265
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• 2007

We constructed a cDNA library of testis from olive flounder (Paralichthys olivaceus) and a total of 248 expressed sequence tag (EST) clones were generated. In order to understand the molecular compositions of the olive flounder testis organs, the expression profiles of the identified clones in the cDNA library were analyzed. Gene annotation procedures and homology searches of the sequenced ESTs were locally done by BLASTX for amino acid similarity comparisons. Of the 248 EST clones, 156 ESTs showed significant homology to previously described genes while 92 ESTs were unidentified or novel. Comparative analysis of the 156 identified ESTs showed that 6 (3.8%) clones were representing 5 unique genes identified as homologous to the previously reported olive flounder ESTs, 100 (64.1%) clones representing 94 unique genes were identified as orthologs of known genes from other organisms, and orthologs were established for 50 (32.1%) clones representing 44 genes of known sequences with unknown functions. Furthermore, the testis library showed a more even distribution of cDNA clones with relatively fewer abundant clones that tend to contribute redundant clones in EST projects; thus, the testis library can supply more unique and novel cDNA sequences in olive flounder EST project.