• Journal of the Korea Computer Industry Society
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• v.2 no.4
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• pp.537-546
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• 2001

Griffth's and LCCMA which are Single-user detection adaptive algorithm are proposed for mitigate MAI(multiple access interference) and the near-far problem in direct-sequence spread-spectrum CDMA system and MOE Algorithm is proposed for MMSE(Minimum Mean-Square Error). This paper pertains to three types of Blind adaptive algorithms which can upgrade system functionality without the requirements from training sequence. It goes further to compare and analyze the functionalities of the algorithms as per number of interfering users or data update rate of the users. The simulation results was that LCCMA algorithm was superior to other algorithms in both areas. Blind application enabled a more flexible network design by eliminating the necessity of training sequence.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.5A
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• pp.452-456
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• 2010

SIR based beam switching in distributed controlled cellular systems is proposed to reduce intercell interference. Compared with Random beam switching that beam switching pattern is randomly selected and cannot avoid beam collision between neighboring cell, SIR based beam switching update its switching pattern based on SIR report from mobile. Neighboring cells independently update their switching patterns and the updated patterns converge to the patterns that minimize beam collision. We shows SIR base beam switching has 20% gain compared with random beam switching in two neighboring cell model.

• Journal of Korea Spatial Information System Society
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• v.11 no.4
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• pp.65-73
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• 2009

With the rapid development of computer, information and communication technologies, the production and distribution of digital contents among various kinds of networks have become more common. In such environment, we need to store and to manage efficiently a large volume of geograpruc data because the amount of geographic data grows faster and faster. In this paper, as a key solution to manage efficiently such a huge amount of geograpruc data, we adopt the mechanism which compresses only the difference between original and updated data with high compression ratio. By transferring highly compressed updated part only instead of the entire of geographic data, we can reduce the network traffic during the download of contents and service.

• Proceedings of the Korea Water Resources Association Conference
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• 2023.05a
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• pp.395-395
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• 2023

전 세계 곳곳에서 매년 발생하고 있는 홍수, 가뭄, 수질 문제는 인류가 해결해야 할 공통적인 문제이다. 홍수, 가뭄, 수질 문제뿐만 아니라 수자원의 지역적인 불균형과 인근 지역의 물 분배 문제, 공유하천 문제 등으로 인한 물 사용자 간의 물 갈등, 물 분쟁도 지속되고 있다. 최근 정보통신기술이 발달함에 따라 수자원 관련 각종 위험지표, 물 갈등, 물 분쟁 사례를 자료화하여 활용할 수 있는 온라인 플랫폼이 개발되고 있다. Aqueduct 3.0은 전 세계 물 위험을 식별하고 평가할 수 있는 물 위험평가 프로그램(water risk assessment tool)으로 세계 수자원 협회에서 2019년 기존 프로그램을 업데이트하여, 온라인 플랫폼을 통해 전 세계 각국의 지역별 수자원 분포에 따른 각종 위험지도와 데이터를 무료로 제공하고 있다. 또한 세계 자연기금(World Wide Fund For Nature)도 온라인 플랫폼으로 전 세계의 물 위험 필터도구(water risk filter tool)를 제공하고 있다. 또한 물 갈등 연대기(Water Conflict Chronology)는 태평양 협회에서 전 세계 물갈등 사례를 수집하여 연대별로 정리한 것으로, 업데이트되어 2022년 사례까지 제공하고 있다. 본 연구는 Aqueduct와 Water Conflict Chronology 등 온라인 플랫폼에 탑재된 한반도 관련 수자원 자료를 조사하여 기존 자료와 분석하였다. 연구 결과 Aqueduct와 Water Conflict Chronology 등 온라인 플랫폼이 수자원 관련 교육의 유용한 도구임을 알 수 있었다.

• The Korean Journal of Malacology
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• v.32 no.3
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• pp.185-188
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• 2016

PANM-DB (version 1.0) was constructed as a web-based interface for the analysis and annotation of Next-Generation Sequencing (NGS) data of Mollusca, Arthropoda, and Nematoda. The database collected the sequences of Protostomes (Mollusca, Arthropoda, and Nematoda) from the NCBI Taxonomy Browser, and the same were compiled in a multi-FASTA format and stored using the formatdb program. This improved the processing of the RNA-seq sequences in terms of speed and hit percentage. PANM-DB has been successfully used for the transcriptome annotation of butterfly, land snail, and other commercial mollusca. We have improved the database by updating the same with new sequences and version 2.0 contains a total of 7,571,246 protein sequences (two times more as compared to version 1.0). Furthermore, the updated version contains the Cephalopoda database. The constructed web interface is available that independently analyses following these updates that is an improvement of the mollusks BLAST server. The updated version of PANM-DB will be helpful for the analysis of the NGS based sequencing data of non-model species, especially Mollusca, Arthropoda, Nematoda.

• Journal of the Korean Association of Geographic Information Studies
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• v.21 no.1
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• pp.83-95
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• 2018

With recent technological advances in the shipbuilding industry, vessels have been improved in size and performance. As a result, an accident such as grounding, caused by a single ship-to-ship collision, could lead to a large-scale maritime disaster. Considering the seriousness of the situation, the international community has been consistently updating the standards for Electronic Navigational Chart(ENC) to improve the maritime safety. S-57, the existing ENC standard governed by the International Hydrographic Organization(IHO), includes standards for generating conventional binary-type ENC data sets. The S-57 standard, however, has not been updated since the release of Version 3.1 in December 2000. Since then, the standard has failed to reflect technological development regarding maritime spacial information, which has been consistently improving. In an effort to address this concern, the IHO designated S-100, i.e., the next-generation ENC production standard. S-100 differs from S-57 in data exchange type. Contrary to the conventional ENC standards, which use binary-type data, S-10X, based on the next-generation ENC standards, uses ENC data composed of Feature Catalogue, Portrayal Catalogue, and GML. Considering this fact, it is necessary to update S-58, the ENC validation check standard, or designate a new standard for ENC validation checks. This study is developed own software to implement validation checks for new types of data, and identified improvement points based on the test results.

• Proceedings of the Korea Information Processing Society Conference
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• 2022.11a
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• pp.727-729
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• 2022

본 연구는 2021 게임업계 연쇄 파동을 통해 게임사 이슈 대응에 대한 사용자들의 인식이 바뀐 것에 주목하여 메이플스토리 확률 조작 사건에서 나타난 사용자들의 반응을 토픽모델링으로 분석하였다. 이를 위해 사건의 발단이 된 메이플스토리 테스트 월드 업데이트 내용이 업로드된 2021년 2월 18일 17시를 기점으로 국내 온라인 게임 커뮤니티 중 하나인 인벤의 자유게시판에서 총 10만 개의 게시물을 수집하고 토픽모델링 분석을 실시하였다. 이후 도출된 주제별 주요 단어를 10개씩 확인하여 주제를 정의했다. 각 토픽을 비교하며 관련성을 확인했고 이를 통해 사용자들의 반응을 분석한 결과 확률 조작으로 인한 보상으로 환불을 원하고 있다는 것과 아이템의 확률을 조작했다는 것에 대한 사용자들의 분노, 디렉터 본인의 직접적인 사과문과 사용자와의 소통 요구, 또 다른 게임으로의 이탈을 확인할 수 있었다.

• The Journal of the Acoustical Society of Korea
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• v.35 no.3
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• pp.234-242
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• 2016

In this paper, an on-line noise coherence estimation algorithm for binaural speech enhancement system is proposed. A number of noise Power Spectral Density (PSD) estimation algorithms based on the noise coherence between two microphones have been proposed to improve the speech enhancement performance. In the conventional algorithms, the noise coherence was characterized using a real-valued analytic model. However, unlike the analytic model, the noise coherence between the two microphones is time-varying in real environments. Thus, in this paper, the noise coherence is updated in accordance with the variation of the acoustic environment to track the realistic noise coherence. The noise coherence can be updated only during the absence of speech, and the simulation results demonstrate the superiority of the proposed algorithm over the conventional algorithms based on the analytic model.

• The KIPS Transactions:PartD
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• v.10D no.3
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• pp.427-438
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• 2003

In a data warehouse, users typically search for trends, patterns, or unusual data behaviors by issuing queries interactively. The OLAP range-sum query is widely used in finding trends and in discovering relationships among attributes in the data warehouse. In a recent environment of enterprises, data elements in a data cube are frequently changed. The problem is that the cost of updating a prefix sum cube is very high. In this paper, we propose a novel algorithm which reduces the update cost significantly by an index structure called the Δ-tree. Also, we propose a hybrid method to provide either approximate or precise results to reduce the overall cost of queries. It is highly beneficial for various applications that need quick approximate answers rather than time consuming accurate ones, such as decision support systems. An extensive experiment shows that our method performs very efficiently on diverse dimensionalities, compared to other methods.

• Journal of KIISE
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• v.43 no.3
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• pp.389-397
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• 2016

In this paper, we propose a highway safety system that comprises a small number of central servers and smart mobile devices. To implement this system, we constructed a central server that collects GPS location information on cars, whose update messages are decreased via the car location estimation algorithm. The in-car mobile devices use the accelerometer sensors to detect hazardous situations; this information is updated to the central server that relays the information to the corresponding endangered cars via location-based unicast using LTE communication. To evaluate the proposed algorithm, we equipped a mobile device app on a real car and conducted real experiments in various environments such as city streets, rural areas, and highway roads. Furthermore, we conducted simulations to evaluate the propagation of danger information. Finally, we conducted simulated experiments to detect car collisions as well as exceptions, such as falling of the mobile device from the cradle.