• Annual Conference of KIPS
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• 2012.11a
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• pp.984-986
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• 2012

디지털 정보량의 증가 추세에 맞추어 네트워크를 통해 자신의 데이터를 원격 저장소에 저장하고, 이를 다양한 디바이스를 통해 언제 어디서나 접근할 수 있는 클라우드스토리지 서비스가 등장하게 되었다. 이는 기존에 데이터를 휴대하기 위해 사용되던 이동식 저장매체와 달리 저장용량의 크기 제한이 없고, 저장매체를 소지해야 하는 문제점이 없어 많은 사용자로부터 사용되고 있다. 이러한 클라우드 스토리지에 여러 사용자의 데이터가 저장됨에 따라 클라우드 스토리지의 신뢰성 문제가 이슈화 되고 있다. 비윤리적인 관리자 및 공격자로부터 클라우드에 저장된 데이터를 안전하게 보호하기 위해 다양한 암호 기술을 클라우드 스토리지에 적용하려는 연구가 진행되고 있다. 하지만 기존의 검색가능 암호기술은 사용자가 저장하고자 하는 데이터를 직접 업로드하고, 해당 자료를 필요에 따라 공유 하고, 공유대상이 변화되는 클라우드 스토리지 환경에서 비효율성을 가지고 있어 실제 서비스에 적용하기 힘든 단점을 가지고 있다. 따라서 본 논문에서는 클라우드 컴퓨팅 환경을 고려하여 검색 가능한 암호화 색인 생성 및 이를 재암호화해 다른 사용자와 안전하게 공유할 수 있는 색인 관리 기법을 제안한다.

• Economic and Environmental Geology
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• v.46 no.2
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• pp.105-121
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• 2013

This study introduces integrated approach on detection of a leakage in a sea wall based on remote sensing, electric resistivity survey, electromagnetic survey, and borehole survey for the Seosan A-Region sea wall. The satellite temperature distribution from Landsat ETM+ data identifies water leakage distribution and period by analyzing temperature mixing patterns between sea water and fresh water. Electric resistivity survey provides both horizontal and vertical anomaly distributions over the sea wall showing below average electric resistivity. Electromagnetic survey(electrical conductivity survey) reveals the potential possible leakage areas with minimal background impact by comparing electrical conductivity values between high and low tides. Borehole image processing system confirmed the locations of anomalies identified from the other survey methods and distributions of vertical fracture zones. The integrated approach identified 41.7% of the sea wall being the most probable area vulnerable to water leakage and effectively approximated both horizontal and vertical distribution of water leakage. The integrated analysis of remote sensing, electric resistivity survey, electromagnetic survey and borehole survey is considered to be an optimal method in identifying water leakage distribution, period, and extent of fractures knowledged from the boreholes.

• Management & Information Systems Review
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• v.38 no.2
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• pp.83-103
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• 2019

Supply chain management(SCM) requires efforts to search for methods for mutual growth with partner companies and to maintain continuous cooperative relations in order to gain a competitive edge. Because information competencies play a big role within the supply chain, it is essential to examine the relationship of information sharing and partnership quality that can affect information competency. In order to maintain continuous business relations between partner companies, it is necessary to identify the obstacles with partner companies resulting from the imbalance of power within a supply chain and to take on a strategic approach for effectively managing such obstacles. Therefore, there is a significant need to discuss strategic approach methods to enable the logic of mutual growth through the CSV that is worth learning from the partner company and the attributes of non-mediated power. CSV will be reviewed from various aspects as a new management paradigm in the future. This study aims at suggesting a continuous growth model for companies by solving social problems through the integration of CSV and the concept of non-mediated power to advance the information competencies of SCM. A total of 142 copies of survey forms for SCM Implementation Companies were using the PLS structural equation modeling for an analysis, and the following are the findings. Results of this study showed that both CSV and non-mediated power had significant impact on information sharing and partnership qualities, and the conclusion that it is possible to enhance information competency through information sharing and partnership quality. Based on this, this study proposes the implication that it is necessary to elevate awareness of CSV and non-mediated power as variables for the coexistence of SCM participating companies.

• Economic Analysis
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• v.27 no.1
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• pp.67-90
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• 2021

This study found an interesting fact that the nonlinear relationship structure between volatility and trading volume changed before and after the COVID-19 pandemic according to empirical analysis using Bitcoin (BTC) market data that sensitively reflects investors' trading behavior. That is, their relationship appeared positive (+) in a stable market state before COVID-19 pandemic, as in theory based on the information flow paradigm. In a state under severe market stress due to COVID-19 pandemic, however, their dependence structure changed and even negative (-). This can be seen as a consequence of increased market stress caused by COVID-19 pandemics from a behavioral economics perspective, resulting in structural changes in the asset market and a significant impact on the nonlinear dependence of volatility and trading volume (in particular, their dependence at extreme quantiles). Hence, it should be recognized that in addition to information flows, psychological phenomena such as behavioral biases or herd behavior, which are closely related to market stress, can be a key in changing their dependence structure. For empirical analysis, this study performs a test of Ross (2015) for detecting a structural change, and proposes a Copula Regression Quantiles (CRQ) approach that can identify their nonlinear relationship structure and the asymmetric dependence in their distribution tails without the assumption of i.i.d. random variable. In addition, it was confirmed that when the relationship between their extreme values was analyzed by linear models, incorrect results could be derived due to model specification errors.

• Journal of Korea Technology Innovation Society
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• v.18 no.1
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• pp.73-97
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• 2015

Various types of government R&D support are available for activating businesses by small and medium sized enterprises (SMEs). However, most existing studies on this topic are focused only on the financial aspect. Interest in non-financial R&D support from the government has recently grown due to the limited provision of government financial support. In this study, government R&D support for SMEs was categorized into financial and non-financial strategies. Performance in terms of technological innovation by type was also analyzed. Furthermore, as R&D performance could vary according to the characteristics of the firms, the study classified performance variables into technological development possibility, technology intensity and technology uniqueness. The relationship between the types of support and the characteristics of the performance was also examined. Based on the results, it was found that government R&D support positively influences the SMEs' technological performance. However, the level of financial support does not significantly influence the technological uniqueness. As such, it is expected that effects from the increase in quantity of government R&D support are limited.

• Tunnel and Underground Space
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• v.19 no.1
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• pp.1-10
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• 2009

Site characterization for structural stability in rock masses mainly involves the collection of joint property data, and in the current practice, much of this data is collected by hand directly at exposed slopes and outcrops. There are many issues with the collection of this data in the field, including issues of safety, slope access, field time, lack of data quantity, reusability of data and human bias. It is shown that information on joint orientation, spacing and roughness in rock masses, can be automatically extracted from LIDAR (light detection and ranging) point floods using the currently available Split-FX point cloud processing software, thereby reducing processing time, safety and human bias issues.

• Proceedings of the Korean Information Science Society Conference
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• 2011.06a
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• pp.73-76
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• 2011

본 논문에서는 기존 단일 인덱스 기반의 왜곡 제거 시계열 서브시퀀스 매칭의 인덱스 구성 알고리즘을 분석하여 보다 효율적인 인덱스 구성 알고리즘을 제안하였다. 기존 왜곡 제거 시계열 서브시퀀스 매칭의 단일 인덱스 구성 알고리즘은 대용량 시계열 데이터인 경우 왜곡 제거를 고려해야 되는 많은 윈도우로 인해 실제 인덱스 생성에 매우 많은 시간이 걸린다. 본 논문에서는 기존 선형 제거 서브시퀀스 매칭의 인덱스 구성 알고리즘을 예로서 인덱스를 구성하는 각 과정을 체계적으로 분석하여, 각 과정에서 필요한 연산 횟수를 줄이는 방법을 제안한다. 이를 위해, 저차원 변환하는 과정에서 발생하는 중복되는 연산들을 한 번씩 미리 수행하여 배열에 저장한 후 재사용하는 DF-버컷(DF-bucket)씨의 개념을 제시한다. 실험 결과, 저장 후 재사용 원칙에 따라 인덱스 구성의 효율성을 증대시킨 접근법이 그렇지 않은 접근법에 비해서 인덱스 구성 시간을 평균 32% 에서 55% 까지 줄인 것으로 나타났다.

• Journal of KIISE:Software and Applications
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• v.30 no.3_4
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• pp.259-267
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• 2003

Though naive Bayes text classifiers are widely used because of its simplicity, the techniques for improving performances of these classifiers have been rarely studied. In this paper, we propose and evaluate some general and effective techniques for improving performance of the naive Bayes text classifier. We suggest document model based parameter estimation and document length normalization to alleviate the Problems in the traditional multinomial approach for text classification. In addition, Mutual-Information-weighted naive Bayes text classifier is proposed to increase the effect of highly informative words. Our techniques are evaluated on the Reuters21578 and 20 Newsgroups collections, and significant improvements are obtained over the existing multinomial naive Bayes approach.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.5A
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• pp.464-472
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• 2011

As wireless sensor networks are applied to various applications such as environment monitoring and disaster sensing system, there are increased needs for wireless communication in underground environment. Since the previous wireless communication technology using electromagnetic wave is not appropriate for the underground environment, a new alternative is required. Recently a magnetic field communication technology has been proposed and standardized as a domestic KS standard. In this paper, we analyze the media access control protocol of the KS standard by an analysis and a simulation study.

• Journal of the Korea Society of Computer and Information
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• v.8 no.4
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• pp.176-185
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• 2003

The SCM is on the effective treatment solution that has process schedule, material supplying, inventory management for perfect product these days. The SCM is innovative process activity to attain effective whole. It depends on the structure of approach because supplying network is consist of organization, budgeting, responsibility and authority. The major objective of the thesis was to propose the integration model and structure method technique of the SCM. Thus, to implement strategy model, firstly, it is determined repairs and non-effectiveness of supplying network. secondly, to set up future vision and goal, it is considered success factor of supplying net. thirdly, no gaps introduce between present and future of supplying net fourthly as above-mentioned consequence, Alternative is to set up integration and implementing model according to enterprise administration strategy .