• Journal of the Institute of Electronics Engineers of Korea SP
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• v.46 no.5
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• pp.8-14
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• 2009

In this paper, a convex optimization technique, which is based on the generalized quantization constraint (GQC), is proposed in the compressive sensing reconstruction using quantized measures. The set size of the proposed GQC can be controlled, and through extensive numerical simulations based on the uniform scalar quantizers, the CS reconstruction errors are improved by 3.4-3.6dB compared to the traditional QC method for the CS problems of m/klogn > 2.

• Information and Communications Magazine
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• v.23 no.11
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• pp.26-39
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• 2006

• Journal of KIISE
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• v.41 no.11
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• pp.992-1005
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• 2014

Coreference resolution finds all expressions that refer to the same entity in a document. Coreference resolution is important for information extraction, document classification, document summary, and question answering system. In this paper, we adapt Stanford's Multi-pass sieve system, the one of the best model of rule based coreference resolution to Korean. In this paper, all noun phrases are considered to mentions. Also, unlike Stanford's Multi-pass sieve system, the dependency parse tree is used for mention extraction, a Korean acronym list is built 'dynamically'. In addition, we propose a method that calculates weights by applying transitive properties of centers of the centering theory when refer Korean pronoun. The experiments show that our system obtains MUC 59.0%, $B_3$ 59.5%, Ceafe 63.5%, and CoNLL(Mean) 60.7%.

• KIPS Transactions on Software and Data Engineering
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• v.5 no.11
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• pp.535-540
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• 2016

Coreference resolution is to identify mentions in documents and is to group co-referred mentions in the documents. It is an essential step for natural language processing applications such as information extraction, event tracking, and question-answering. Recently, various coreference resolution models based on ML (machine learning) have been proposed, As well-known, these ML-based models need large training data that are manually annotated with coreferred mention tags. Unfortunately, we cannot find usable open data for learning ML-based models in Korean. Therefore, we propose an efficient coreference resolution model that needs less training data than other ML-based models. The proposed model identifies co-referred mentions using random forests based on sieve-guided features. In the experiments with baseball news articles, the proposed model showed a better CoNLL F1-score of 0.6678 than other ML-based models.

• The Optical Journal
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• s.156
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• pp.52-60
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• 2015

선진국 스마트폰 시장이 포화상태에 도달함에 따라 주요 IT기업들의 차세대 IT 비즈니스 발굴이 큰 화두다. 차세대 IT 비즈니스의 주목할만한 후보군 중 하나는 가상현실(VR: Virtual Reality)이다. 최근 고해상도 디스플레이, 강력한 컴퓨팅 파워, 3D센싱 등의 기술이 비약적으로 발달하고 하드웨어 비용이 크게 하락함에 따라 드디어 일반 사용자들을 대상으로 유의미한 수준의 '몰입감'과 '상호작용'을 제공할 수 있는 환경이 조성됐다. 현재 삼성전자, 소니, 엡슨 등의 대기업들이 VR 헤드셋 개발에 뛰어들었으며 뷰직스(Vuzix), 아 베간트(Avegant), 버추익스(Virtuix), 시브라이트(Seebright) 등의 가상현실 벤처기업들이 크게 주목을 받으면서 해당 업체들에 투자하겠다는 문의가 쇄도하고 있는 실정이다. 향후 가상현실 시장은 기업들에게 엄청난 비즈니스 기회를 제공할 것으로 전망된다. 단지 VR 헤드셋이나 관련 기기의 매출보다는 가상공간에서 사용자들이 소비하는 시간과 비용이 중요하다. 기존 오프라인, 온라인의 비즈니스 모델과 수익 모델 대부분을 가상현실에서 구현할 수 있다. 사람들은 앞으로 현실환경의 모든 오브젝트와 연결돼 상호작용을 하고, 또한 가상환경의 모든 오브젝트와 연결돼 상호작용을 하게 될 것이다. 그것이 진정한 사물인터넷과 가상현실이다.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.16 no.3
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• pp.103-108
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• 2007

The number of parts made of ceramic materials has gradually been increasing in field of from mechanical engineering to electronics engineering and, mechanical engineering ceramics have spread because of three very favourable characteristic features of their application, namely, heat, wear, and corrosion resistance. therefore, the elaboration of suitable grinding technologies is Important. grinding is problematic because crack-free ceramics are difficult to process owing to their particular micro structure. In this paper we report on the application of advanced precision grinding process, elaborating continuous wheel dressing. The removal rate can be increased significantly and surface roughness is improved. Various problems(roughness, ground surface etc)encountered in grinding of ceramics are also discussed.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2004.11a
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• pp.306-311
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• 2004

The sliding wear characteristics of the crane sheave were investigated using a pin-on-disk rig tester The experiment was conducted using a high carbon steel wire that was upper material, also carbon steel castings and carbon steel for machine structural use that was disk material. There are various operating conditions in this work. At the room temperature, we carried out the wear test under a grease lubrication. The results of wear test showed that carbon steel for machine structural use have lower wear volume, also the wear curves are linearly increased with increasing of sliding velocity The wear mechanism of a disk is the abrasive, adhesion, and fatigue wear under lubrication.

• Journal of the Mineralogical Society of Korea
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• v.8 no.2
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• pp.118-125
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• 1995

경북 구룡포에 소재한 구룡광산에서 산출하는 불석(클리놉틸로라이트와 모데나이트의 집합체)에 대한 Pb2+, Cd2+, Zn2+, Co2+, Fe2+ 및 NH4+ 등 양이온의 치환성질을 알아보기 위하여 베치실험을 실시하였다. 60∼80 메쉬 및 230 메쉬의 시료를 사용하여 각각 50ppm의 농도를 가진 용액과 반응시켰다. 반응후의 용액은 AA 및 전극 (NH4+)으로 분석하여 치환양을 측정하였다. 본 연구결과 Pb2+와 NH4+가 다른 이온들보다 훨씬 높은 선택성을 보여 주었다. 불석에 대한 이온들의 선택성은 NH4+, Pb2+》Zn2+, Cu2-, Co2->Cd2-, Fe2+와 같다. 실험결과 불석시료가 용액으로부터 흡착한 양이 시료로부터 용액으로 추출된 양보다 훨씬 높게 나타나고 있는 바 이는 이온치환보다는 불석의 시브(sieve) 효과에 의한 이온흡착현상이 우세하게 일어났다는 것을 지시해준다. 본 실험은 이 불석이 중금속과 암모니아와 같은 오염물을 제거하는데 사용될 수 있음을 보여준다.

• Korean Journal of Materials Research
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• v.9 no.2
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• pp.139-143
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• 1999

Solidification simulation of gray cast iron sheave product was conducted with the consideration of graphite precipitation during solidification, and of casting processes such as post-inoculation method, treatment and rate, the result of which was aimed to be adopted in the field. In risering design(I), shrinkage cavities were predicted to occur in the part below the risers and center part of the product. While the former defect was considered to be due to the solidification behaviour of riser neck, the latter was due to the feeding channel. In design(II), the length of the riser neck was reduced and one top open riser was attached in the center of the product to prevent the formation of shrinkage cavities, whereby defect-free product was produced.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.9
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• pp.1522-1530
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• 2008

This paper presents a discrete wavelet analysis based algorithm to address the fault impedance calculation under transient state in radial power distribution networks. The fault impedances have been derived under different fault conditions. Furthermore, a recursive fault distance estimation method is proposed utilizing the measured fault impedance and power line parameters. The proposed scheme can resolve the errors caused by the non-homogeneous power lines, the presence of lateral loads since, the fault impedance will always be updated with the recursive form. For the verification of the proposed scheme, a filed test has been peformed with varying fault resistances in the 22.9(kV) radial system. Power meters and fault locators were installed at the substation. It was figured out that the performance of the discrete wavelet and the recursive scheme are very good even for high fault resistance condition.