• Journal of Korea Society of Industrial Information Systems
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• v.13 no.3
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• pp.54-62
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• 2008

For a message hiding technique to be effectual, it needs to have availability, confidentiality and integrity. Steganography is the science of hiding one message within other types of digital contents. In this case, attempt to defeat steganalysis by restoring the statistics of the composite image to resemble that of the cover, these discrepancies expose the fact that hidden communication is happening. In this paper, I present a steganography scheme capable of concealing a piece of secrete information in a host image and base on the technique's OCT, RGB, statistical restoration.

• Journal of Korea Society of Industrial Information Systems
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• v.14 no.3
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• pp.37-43
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• 2009

Steganography conceals the fact that hidden message is being sent on the internet. Steganalysis can be detected the abrupt changes in the statistics of a stego-data. After message embedding, I have analyzed for the statistical significance of the fact the occurrence of differences among the four-neighboring pixels. In this case, when a embedding messages within a images is small, use EC value and chi-square test to determine whether a distribution in an images matches a distribution that shows distortion from stego-data.

• Proceedings of the Korea Contents Association Conference
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• 2011.05a
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• pp.209-210
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• 2011

본 연구는 학교보안관 제도에 대한 학부모 인식을 조사하는데 목적을 두고 있다. 이를 위하여 이 연구에서는 서울시 4개구를 무작위로 선정하여 107명을 추출하여 분석하였다. 설문지의 타당도는 전문가회의와 요인분석, 신뢰도는 신뢰도 분석을 통하여 검증하였다. 통계처리는 카이스퀘어 검증과 t검정, F검정 등이 실시되었다. 결론은 다음과 같다. 첫째, 개인적 특성에 따라 학교보안관 제도의 필요성은 차이가 있다. 둘째, 개인적 특성에 따라 학교보안관의 학교생활 도움정도는 차이가 있다. 셋째, 개인적 특성에 따라 학교보안관 만족은 차이가 있다.

• Proceedings of the Korean Information Science Society Conference
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• 2005.07b
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• pp.607-609
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• 2005

온라인 및 오프라인 상에서 추천시스템에 대한 요구가 커지고 있으며 이에 관련해 않은 연구가 이루어지고 있다. 추천시스템은 마케팅 활용의 관점에서 목표 상품에 대한 반응 가능성이 높은 고객군을 추천하는 타겟마케팅 추천시스템과 고객 개인별로 구매 가능성이 높은 상품을 추천하는 개인화 추천시스템으로 구분할 수 있다. 지금까지의 추천시스템에 관한 연구는 대부분 개인화 추천시스템의 효율 향상에 목표를 두고 있다. 그러나 기업의 타겟마케팅에 대한 요구를 적절히 지원하지 못하고 있어 타겟마케팅에 대한 연구가 필요하다. 본 연구에서는 상품별 구매 패턴을 이용하는 프로파일 기반 추천 방법을 제안하고 이 방법과 기존의 협력적 추천 방법을 결합하여 특정 상품에 반응 가능성이 높은 고객을 추천하는 방법을 제안한다. 프로파일 기반 추천에서는 카이스퀘어 검정을 사용하여 상품별로 구매 패턴에 영향을 미치는 요인을 추출하고 이를 이용하여 특징 고객군을 선별하여 전체 고객군과 특징 고객과의 엔트로피(Entropy)의 변이 정도를 예측값으로 사용한다. 실험결과, 프로파일 기반 추천과 협력적 추천을 결합하여 추천하는 방법은 한 가지 방법을 사용할 때 보다 좋은 추천 정확도를 나타내었다.

• Proceedings of the Korea Information Processing Society Conference
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• 2001.10b
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• pp.1001-1004
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• 2001

현재 네트워크 기반의 침입 탐지는 대부분 오용 탐지 기법을 사용한다. 하지만 이는 알려지지 않은 침입을 탐지하는 능력이 떨어지는 기법으로서 이를 보완할 수 있는 비정상행위 탐지 기법을 찾는 것이 필요하다. 따라서 수집된 감사 자료로부터 정상행위를 프로파일링하고 침입임을 판정하는데 통계적인 기법을 사용하였다. 수집된 로그로부터 통계적인 방법으로 정상행위를 프로파일링하기 위해 우선 패킷으로부터 수집되는 감사 자료의 통계적인 특성을 대변하는 분포와 파라미터를 추정하고 카이스퀘어 검정법을 사용하여, 감사 자료가 가설하는 이론적인 분포의 특성을 가지고 있다고 판정되면 이를 정상행위의 기준으로 삼는다. 이후에 수집되는 감사자료를 감시하기 위해 추정된 분포와 파라미터를 따르고 있는지의 여부를 Kolmogorov-Smirnov 적합도 검정을 이용하여 판별하고, 이를 벗어나는 경우 침입으로 판정할 수 있도록 한다.

• Culinary science and hospitality research
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• v.23 no.2
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• pp.104-116
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• 2017

The purpose of this study was to conduct an empirical survey on consumer perception and consumption behavior in relation to local food and eco-friendly food. The survey was conducted using 266 consumers who have heard about or purchased local foods and eco-friendly foods centering on Seoul and Gyeonggi-do, and statistical analysis was carried out using SPSS (Version 23.0) to generate descriptive statistical values such as frequency and percentage and implement a Chi-square test. The results showed that consumers purchased local food in large shopping malls, supermarkets, and local food stores, whereas eco-friendly food were usually bought in large shopping malls, supermarkets, and eco-friendly food specialty stores. For local food, consumers bought fruits the most, followed by vegetables, whereas for eco-friendly food, consumers purchased vegetables the most, followed by fruits. The top reason for purchasing local food was its "fresh and high quality," whereas the top reason for buying eco-friendly food was "safety from pesticides and additives." According to results of the Chi-square test, women, unmarried people and younger people turned out to have more experiences in purchasing local foods and eco-friendly foods compared to men, married people and older people, respectively. Although local and eco-friendly food were completely different concepts, results of the study show that consumers were not able to make a clear distinction between the two. Consumer education, therefore, should involve defining the two types of food and spreading awareness on local and organic food to help them made the right choices when buying food.

• Journal of the Korean Geographical Society
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• v.42 no.4
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• pp.616-631
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• 2007

Residential differentiation is an academic theme which has been given enormous attention in urban studies. This is due to the fact that residential segregation can be seen as one of the best indicators for socio-spatial dialectics occurring on urban space. Measuring how one population group is differentiated from the other group in terms of residential space has been a focal point in the residential segregation studies. The index of dissimilarity has been the most extensively used one. Despite its popularity, however, it has been accused of inability to capture the degree of spatial clustering that unevenly distributed population groups usually display. Further, the spatial indices of segregation which have been introduced to edify the problems of the index of dissimilarity also have some drawbacks: significance testing methods have never been provided; recent advances in spatial statistics have not been extensively exploited. Thus, the main purpose of the research is to devise a spatial separation measure which is expected to gauge not only how unevenly two population groups are distributed over urban space, but also how much the uneven distributions are spatially clustered (spatial dependence). The main results are as follows. First, a new measure is developed by integrating spatial association measures and spatial chi-square statistics. A significance testing method based on the generalized randomization test is also provided. Second, a case study of residential differentiation among groups by educational attainment in major Korean metropolitan cities clearly shows the applicability of the analytical framework presented in the paper.

• The Journal of the Korea Contents Association
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• v.11 no.12
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• pp.774-784
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• 2011

The purpose of this study, which was conducted as a part of investigations for vitalizing the School Sheriff system proposed as a means to prevent school violence and promote school safety, was to survey recognition of elementary school parents toward the School Sheriff system and present an improvement scheme for the system. For the study, we selected as the research object a set of parents whose children attended schools with School Sheriffs and then sampled 200 parents out of them with cluster random sampling, before analyzing 189 finally. Validity of the questionnaire is verified by expert council and factorial analysis, and reliability by reliability analysis. Statistical means including chi-square test, t-test and F-test are used. The result of the study as follows : First, necessity of the School Sheriff system varies by individual characteristics. Second, recognition toward the system itself varies by individual characteristics. Third, recognition toward the role that should be played by School Sheriffs varies by individual characteristics. Fourth, there is a difference in perceiving the role and activity of School Sheriffs, Fifth, whether the system helped improving school safety varies by individual characteristics. Sixth, the satisfaction from the School Sheriffs.

• Journal of the Korean Society of Physical Medicine
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• v.6 no.4
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• pp.415-424
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• 2011

연구목적 : 본 연구는 볼기신경 뿌리병증 환자에 대하여 역학적 스트레스인 압박과 긴장을 가하여 환자의 증상을 나타내 신경동역학적 검사간의 상관관계를 수행하였다. 연구방법 : 신경동역학검사인 하지직거상검사, 수정된 활시위검사, 슬럼프검사에 앞서 방사선과 전문의에 의해 자기공명영상 판독을 실시하여 허리원반 이탈로 진단받은 다리쪽으로 방사통을 호소하는 21명의 환자가 참여 하였다. 수집된 자료는 질적변수에 따른 빈도와 비율은 교차분석표로 작성하였고, 신경동역학적 검사간의 상관관계를 검정하기 위해 피어슨의 카이스퀘어(Pearson's chi-square)을 시행하였다. 연구결과 : 허리 자기공명영상 결과, 증상에 대한 두 검사 간 교차표를 작성하여 하지직거상검사와 수정된 활 시위검사, 하지직거상검사와 슬럼프검사는 유의한 상관관계는 없었지만(p>.05) 수정된 활시위검사와 슬럼프검사는 통계적으로 유의한 상관관계(p<.05)가 제시되었다. 결론 : 볼기신경 뿌리병증 환자에 대한 신경동역학검사인 수정된 활시위검사와 슬럼프검사가 통계적으로 유의한 상관관계를 나타내는 증거를 제공하였다. 신경동역학 검사는 신경계에 역학적 스트레스 즉, 긴장, 활주, 또는 압박 자극을 주어 신경기능이상 환자에 대해 적절한 검사를 제시하였다.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 1998.10a
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• pp.107-115
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• 1998

For the purpose of building the simulation model on cargo handling capacity of container terminal, we composed a model of container logistics system which has a 4 subsystems ; cargo handling, transportation, storage system and Gate complex system. Several date used in simulation gained through spot research and basic statistic analysis using raw data from January to Jane in 1998. The results of this study are as follows ; First, average available ratio of each subsystem was G/C 50%, Y/T 57.5%, storage system 56%, Gate complex 50%, and there was no subsystem occurring specific bottleneck. Second, comparing the results of simulation to the results of basic statistics, we can verify suitability of this simulation model. Third, Comparing the results of this study to the results of existed study, we were able to confirm a change of BCTOC container logistics system under IMF situation.