• 한국빅데이터학회지
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• 제3권2호
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• pp.11-18
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• 2018

본 연구는 빅데이터 품질 진단의 핵심 요소인 도메인 기반 품질 진단을 위한 도메인 자동 판별에 관한 연구다. 빅데이터의 가치와 활용도의 증가와 4차 산업혁명의 대두로, 법률, 의료, 금융 등 IT와 융합된 다양한 분야에서 빅데이터를 활용하여 새로운 가치를 창출하려는 노력을 진행중이다. 하지만, 신뢰도가 낮은 데이터에 기반한 분석은 과정과 결과 모두에서 치명적인 문제를 발생하며, 분석 결과에 따른 판단 또한 신뢰하기 어려워 진다. 이처럼 신뢰도가 높은 데이터의 필요성 또한 증가하였지만, 데이터의 품질 확보에 대한 연구와 그에 대한 결과는 미비하다. 본 연구는 데이터 품질 향상을 위한 진단 평가의 핵심적 요소인 도메인 기반 품질 진단에서, 수작업으로 진행되었던 도메인 판별 작업을 머신러닝을 이용하여 자동화 함으로써, 작업시간을 단축하는 것을 목표로 한다. 데이터 베이스에 저장된, 도메인이 판별되어 있는 데이터의 특성에 관한 정보들을 추출하여 변수화하고, 이를 머신러닝을 이용하여 도메인 판별을 자동화 한다. 이를 빅데이터 품질 진단에 활용하고, 품질 향상에 기여하도록 한다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제14권10호
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• pp.4042-4059
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• 2020

The development of new multimedia techniques such as 3D printing is increasingly attracting the public's attention towards 3D objects. An optimized robust and imperceptible watermarking method based on Ant Colony Optimization (ACO) and Weber Law is proposed for 3D polygonal models. The proposed approach partitions the host model into smaller sub meshes and generates a secret watermark from the sub meshes using Weber Law. ACO based optimized strength factor is identified for embedding the watermark. The secret watermark is embedded and extracted on the wavelet domain. The proposed scheme is robust against geometric and photometric attacks that overcomes the synchronization problem and authenticates the secret watermark from the distorted models. The primary characteristic of the proposed system is the flexibility achieved in data embedding capacity due to the optimized strength factor. Extensive simulation results shows enhanced performance of the recommended framework and robustness towards the most common attacks like geometric transformations, noise, cropping, mesh smoothening, and the combination of such attacks.

• 한국융합학회논문지
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• 제9권10호
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• pp.45-53
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• 2018

최근 이중 언어 임베딩(bilingual word embedding) 관련 연구들이 각광을 받고 있다. 그러나 한국어와 특정 언어로 구성된 병렬(parallel-aligned) 말뭉치로 이중 언어 워드 임베딩을 하는 연구는 질이 높은 많은 양의 말뭉치를 구하기 어려우므로 활발히 이루어지지 않고 있다. 특히, 특정 영역에 사용할 수 있는 로컬 이중 언어 워드 임베딩(local bilingual word embedding)의 경우는 상대적으로 더 희소하다. 또한 이중 언어 워드 임베딩을 하는 경우 번역 쌍이 단어의 개수에서 일대일 대응을 이루지 못하는 경우가 많다. 본 논문에서는 로컬 워드 임베딩을 위해 한국어-영어로 구성된 한국 법률 단락 868,163개를 크롤링(crawling)하여 임베딩을 하였고 3가지 연결 전략을 제안하였다. 본 전략은 앞서 언급한 불규칙적 대응 문제를 해결하고 단락 정렬 말뭉치에서 번역 쌍의 질을 향상시켰으며 베이스라인인 글로벌 워드 임베딩(global bilingual word embedding)과 비교하였을 때 2배의 성능을 확인하였다.

• 한국컴퓨터정보학회논문지
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• 제22권2호
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• pp.97-104
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• 2017

In semantic information retrieval, we first need to build domain ontology and second, we need to convert the users' search keywords into a standard query such as SPARQL. In this paper, we propose a method that can automatically convert the users' search keywords into the SPARQL queries. Furthermore, our method can ensure effective performance in a specific domain such as law. Our method constructs the keyword history ontology by associating each keyword with a series of information when there are multiple keywords. The constructed ontology will convert keyword history ontology into SPARQL query. The automatic transformation method of SPARQL query proposed in the paper is converted into the query statement that is deemed the most appropriate by the user's intended keywords. Our study is based on the existing legal ontology constructions that supplement and reconstruct schema and use it as experiment. In addition, design and implementation of a semantic search tool based on legal domain and conduct experiments. Based on the method proposed in this paper, the semantic information retrieval based on the keyword is made possible in a legal domain. And, such a method can be applied to the other domains.

• 한국전기전자재료학회논문지
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• 제17권1호
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• pp.46-51
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• 2004

The cause for the variation of the initial permeability according to the Co substitution of Ni-Zn ferrite used in the LC resonance filter for the power line communication is studied. The initial permeability decreases as the quantity of Co diminishes, and the saturation magnetization increases as the quantity increases. Because the sintering density and the microstructure of ferrite show little change, the variation of the initial permeability can't be explained by the density, microstructure nor the saturation magnetization factor. The magnetocrystalline anisotropy increases, similar with the saturation magnetization, as the quantity of Co increases. The increase of magnetocrystalline anisotropy value makes the domain wall energy grow, which leads to the decrease of the initial permeability, because there's linear law between the magnetocrystalline anisotropy and the domain wall energy. The resonance frequency to Co substitution moved to high frequency band, due to the close relationship with domain wall energy, Initial permeability decreaed a little with an increase of Co contents, but resonace frequency moved to high frequency band. as a result of that, when Co was added 0.05 mol, initial permeability and resonace frequency was 75 and 25 MHz respectively.

• 대한조선학회논문집
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• 제55권6호
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• pp.466-473
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• 2018

Most frequency domain-based approaches assume that structural response should be a Gaussian random process. But a lot of non-Gaussian processes caused by multi-excitation and non-linearity in structural responses or load itself are observed in many real engineering problems. In this study, the effect of non-Normality on fatigue damages are discussed through case study. The accuracy of four frequency domain methods for non-Gaussian processes are compared in the case study. Power-law and Hermite models which are derived for non-Gaussian narrow-banded process tend to estimate fatigue damages less accurate than time domain results in small kurtosis and in case of large kurtosis they give conservative results. Weibull model seems to give conservative results in all environmental conditions considered. Among the four methods, Benascuitti-Tovo model for non-Gaussian process gives the best results in case study. This study could serve as background material for understanding the effect of non-normality on fatigue damages.

• 전산구조공학
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• 제6권2호
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• pp.103-114
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• 1993

유전적분형 물성방정식에 근거한 선형 점탄성문제의 효율적인 수치해석을 위해서 새로운 유한요소해법을 공식화하였다. 각 시간구간에서 변수변화를 선형적으로 가정하고 유전적분의 계산을 매우 효율적으로 처리하였다. 그 결과 과거의 해석법에 비하여 수치정확도 및 경제성에서 큰 향상을 얻었다.

• 대한기계학회논문집
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• 제19권3호
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• pp.623-630
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• 1995

The impulse response functions (force-strain relations) for Euler-Bernoulli and Timoshenko beams are considered. The response of a beam to a transverse impact force is numerically obtained with the convolution approach using the impulse response function obtained by Laplace transform. Using this relation, the impact force history is determined in the time domain and results are compared with those from Hertz's contact law. The parameters of timpact force model are identified using the recovered force and compared with the Hertz's contact model. In order to verify the proposed algorithm, measurements were done using an impact hammer and a steel ball drop test and these results are also compared with the simulated values.

• 무역상무연구
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• 제63권
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• pp.245-260
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• 2014

This study is aimed to summarize a tense situation of Risk management for Kaesong Industrial Business Enterprise in 2013 and to investigate trade insurance of K-sure. Now we have to find a new way to protect Kaesong Industrial Business Enterprises from uncertain environment and also need to prevent a recurrence of parallel cases in the domain of South-North economic cooperation in Korean peninsula. There are two method to protect Kaesong Industrial Business Enterprises. First they rely on the Korea government for protection. Second they need to effect trade insurance of K-sure. such as Export Credit Guaranty or Short-term Export Insurance. They shall create a wise predictable environment to protect Kaesong Industrial Business Enterprises themselves without resort to Korea government. Of course there are many things left behind to consider I hope it will be helpful to those who prepare South-North economic cooperation especially in Kaesong Industrial Complex.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2006년도 춘계학술대회 논문집
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• pp.163-164
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• 2006

In this paper, an analytical laser ablation model with Maxwell equation will be addressed by considering relationship between laser ablation and material. The Maxwell equation consists of four equations: two Gauss laws for electric and magnetic fields, Faraday's law, and Ampere's law. This analytical model will be calculated by employing Finite Difference Time Domain (FDTD). This method also makes it possible to simulate the laser beam propagation in a wide range of materials, such as metals, semiconductors, and dielectrics. Therefore, in this study, a numerical model for short pulse laser interaction with materials is developed, focusing on the accurate description of laser beam propagation and ablation process into the material with each pulse.