• Journal of the Korean Data and Information Science Society
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• 제16권2호
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• pp.195-205
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• 2005

In decision tree analysis, C4.5 and CART algorithm have some problems of computational complexity and bias on variable selection. But QUEST algorithm solves these problems by dividing the step of variable selection and split point selection. When input variables are continuous, QUEST algorithm uses ANOVA F-test under the assumption of normality and homogeneity of variances. In this paper, we investigate the influence of violation of normality assumption and effect of the transformation of variables in the QUEST algorithm. In the simulation study, we obtained the empirical powers of variable selection and the empirical bias of variable selection after transformation of variables having various type of underlying distributions.

• 인터넷정보학회논문지
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• 제11권6호
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• pp.123-133
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• 2010

XML은 웹상에서 데이터를 만들고 교환하기 위한 새로운 표준이 되었다. 그러나 대부분의 비즈니스 데이터는 아직까지 관계형 데이터베이스 관리 시스템으로 저장되고 관리되고 있다. 따라서 효과적으로 관계형 데이터를 인터넷 기반의 XML 데이터로 변환하는 필요성이 증대되고 있다. 변환 과정에서 가장 중요한 점은 관계형 스키마의 구조적, 의미적 관계 정보를 XML 스키마에 정확히 반영하는 것이다. 그러나 대부분의 변환 방법들이 이러한 관계 정보들을 지원하지 못하는 문제점을 지니고 있다. 이 논문에서는 관계형 데이터베이스 스키마를 XML 스키마인 XML Schema로 변환하는 알고리즘을 제안한다. 변환에는 명시적/묵시적 참조 무결성 관계 정보뿐만 아니라 데이터 중복이 없는 중첩 구조의 높은 단계를 달성할 것이다. 이 논문에서의 절차는 우선 참조 무결성 정보를 추출하여 중복 배제 스키마 모델을 제안하고, 그리고 중첩 구조를 탐사함으로 데이터 중복이 없는 XML Schema 구조를 개선한다.

• 한국지구과학회지
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• 제35권1호
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• pp.69-87
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• 2014

이 논문에서는 구성 자료의 지구통계학적 시뮬레이션을 위해 다중 자료 변환 기반 조건부 시뮬레이션 틀을 제안하였다. 우선 일반적인 통계 기법의 적용이 가능하도록 구성 자료에 로그비 변환을 적용하였다. 다음 변환들로는 최소/최대 자기상관 인자 변환과 지시자 변환을 순차적으로 적용하였다. 독립적인 새로운 변수의 생성을 위해 최소/최대 자기상관 인자 변환을 적용하였으며, 적용 결과 개별 변수들의 독립적인 시뮬레이션이 가능해진다. 그리고 다중 가우시안 확률 모델을 따르지 않는 변수들의 비모수적 조건부 누적 확률 분포 모델링을 위해 지시자 변환을 적용하였다. 최종적으로는 적용한 변환 방법들의 역순으로 역 변환을 적용하였다. 간석지 표층 퇴적물 성분 자료를 대상으로 제안 시뮬레이션 기법의 적용 가능성을 예시하였다. 모든 시뮬레이션 결과들은 구성 자료의 제한 조건을 만족하면서 샘플 자료의 통계 특성을 잘 반영하였다. 구성 자료의 다수의 시뮬레이션 결과들을 이용한 표층 퇴적물 분류를 통해 기존 크리깅에서는 얻을 수 없는 분류 결과의 확률론적 평가가 가능하였다. 따라서 제안 시뮬레이션 틀은 다양한 구성 자료의 지구통계학적 시뮬레이션에 효과적으로 이용될 수 있을 것으로 기대된다.

• 한국주거학회:학술대회논문집
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• 한국주거학회 2011년도 춘계학술발표대회 논문집
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• pp.89-92
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• 2011

Built in 1944, in Busan, Sohawjang has currently remained in severe state of transformation. Sohawjang is a rare case of modern housing complex in Korea and it is a significant historic building as housing history and technique history. This study is to leave the basic data about modern housing by finding the substance of Sohawjang, a unusual case of modern housing complex in Korea, and examples of housing transformation through this study. This study attempts to find the original shape and architectural history about Sohawjang, modern apartment building, and analyze the actual conditions of transformation. For implementing, this study carried out the surveys and interviews with experimental research. As the result of the study, after the independence, various cases of transformation were investigated from floor plan of Japanese middle corridor. This study classified according to types of housing by analyzing outcomes and examined the reason and characteristic of transformation. This study discovered the Sohawjang's housing transformation cases, modern housing complex, that has not been disclosed so far and draw the characteristic of transformation as the Architectural Planning.

• Journal of Welding and Joining
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• 제17권6호
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• pp.84-89
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• 1999

Most of ferrous b.c.c weld materials may experience martensitic transformation during rapid cooling after welding. It is well known that volume expansion due to the phase transformation could influence on the relaxation of welding residual stress. To apply this effect practically, it is a prerequisite to establish a numerical model which is able to estimate the effect of phase transformation on residual stress relaxation quantitatively. For this purpose, the analysis is carried out in two regions. i.e., heating and cooling, because the variation of material properties following a phase transformation in cooling is different in comparison with the case in heating, even at the same temperature. The variation of material properties following phase transformation is considered by the adjustment of specific heat and thermal expansion coefficient, and the distribution of residual stress in analysis is compared with that of experiment by previous study. consequently, in this study, simplified numerical procedures considering phase transformation, which based on a commercial finite element package was established through comparing with the experimental data of residual stress distribution by other researcher. To consider the phase transformation effect on residual stress relaxation, the transition of mechanical and thermal property such as thermal expansion coefficient and specific heat capacity was found by try and error method in this analysis.

• Asian Pacific Journal of Cancer Prevention
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• 제14권8호
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• pp.4693-4697
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• 2013

Background: Malignant transformation arising in mature cystic teratoma (MCT) is one of the most serious complications of MCT. Squamous cell carcinoma is the most common malignant change. Some clinical findings such as advanced age group and large tumor size are significant risk factors of malignant transformation. This study was conducted in order to evaluate characteristics, cell types, treatment and outcome of malignant transformation arising from dermoid cysts in our institution. Materials and Methods: A retrospective chart review was performed. General characteristics, operative data, procedure, operative finding and operative outcome were analyzed. Statistical assessment was performed with SPSS version 17.0, using mean, mode, median and percentage to describe those data. Results: During the 10 years period, 11 cases of malignant transformation from a total of 753 cases (1.46% incidence) of MCT were reviewed. Mean age of the patients was 41.2 years (SD 4.34, range 24-70). The most common presenting symptom was a palpable mass (8 cases; 72.7%). Primary surgical staging was performed in 4 patients (36.4%). Re-staging was conducted in the other 4. Complete cytoreduction was obtained in 45.5% (5 cases) and optimal surgical resection was obtained in 36.4% (4 cases). Mean tumor size was 14.1 cm. (SD 1.55, range 6-20). Squamous cell carcinoma was found in 36.4% (4 cases) and mucinous cancer in the other 4. More than half of them were stage Ia (54.5%, 6 cases). All patients whose stage more than Ia received chemotherapy (45.5%). Mean disease free survival was 5.53 years (1.32, 0.3-10). Conclusion: According to our study, the incidence of malignant transformation was consistent with previous studies. The common malignant transformation histologic types are both squamous and mucinous carcinoma which differed from previous reports. Early detection for early stage disease and optimal surgery are important for long term survival.

• 한국빅데이터학회지
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• 제7권1호
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• pp.139-171
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• 2022

빅데이터와 제4차산업혁명은 새로운 형태의 에너지를 낳지 않고 디지털화라는 새로운 기술적 현상을 촉발한 최초의 혁명이다. 디지털트랜스포메이션은 파괴적인 혁신을 야기 시켰고, 각 나라와 주요 기업들은 이에 대한 대응이 필요한 상황이다. 이러한 중요성에도 불구하고, 국내외 실증연구는 미흡한 실정이다. 따라서 본 연구에서는 기업의 디지털트랜스포메이션 추진에 영향을 미치는 요인을 문헌고찰을 통해 발굴하고, 델파이 스터디를 통해 수정 및 보완하여 연구모형을 개발하고 실증 분석하였다. 연구모형은 IDT와 TOE 모델을 결합하여 기술, 혁신, 조직, 환경 등의 주기준과 17개의 하부기준으로 구성되었다. 이를 실증분석하기 위해 국내 디지털트랜스포메이션 추진 주관사 및 협력사의 전문가를 대상으로 AHP의사결정기법을 이용하였다. 디지털트랜스포메이션을 추진하는 기업들은 기업이 속한 집단의 업종 및 기업규모 관점의 특성에 따라 디지털트랜스포메이션 추진에 영향을 미치는 요인들을 고려하여 추진한다면 성공적인 디지털트랜스포메이션의 달성 가능성을 높일 수 있을 것이다.

• 한국컴퓨터정보학회논문지
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• 제9권4호
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• pp.5-12
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• 2004

XML과 데이터베이스간의 자료 변환의 원리는 XML과 데이터베이스 간 매칭의 원리로 이루어진다. SQL Server의 데이터에 접근하기 위한 방법은 URL에 SQL 쿼리를 지정하는 방법과 template 파일을 이용하는 방법이 있다. MS-SQL 서버는 OpenXML 기능을 이용하여 기존의 관계형 데이터베이스에 대해 SQL 쿼리를 실행한 결과를 XML 문서로 변환한다. 즉, OpenXML은 노드 트리를 생성한 후에 XML 문서의 로우셋 데이터를 반환하고, XML 데이터를 관계형 형식으로 얻게 한다. XML 데이터를 데이터베이스 데이터로 삽입하기 위해서는 sp_xml_preparedocument 프로시져를 사용하여, XML 문서를 파싱해 데이터를 추출한 후. 그 문서의 노드 구조를 메모리의 트리 구조로 매핑해서 데이터베이스 테이블에 저장하게 된다. 결국 XML과 데이터베이스간의 자료 변환의 원리는 XML과 데이터베이스간 매칭의 원리로 이루어진다. 본 논문에서는 매핑 원리를 제시한 후 SQL Server의 지원하에 두 자료간의 변환을 구현해 보임으로서 자료의 확장성과 효율성 및 다양한 효과를 가져올 수 있음을 제시하고 있다.

• 대한기계학회논문집A
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• 제24권10호
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• pp.2552-2559
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• 2000

Most of ferrous b.c.c weld materials have martensitic transformation during rapid cooling after welding. It is well known that volume expansion due to the phase transformation could influence on the relaxation of welding residual stress. To apply this effect practically, it is necessary to establish a numerical model which is able to estimate the effect of phase transformation on residual stress relaxation quantitatively. For this purpose, the analysis is carried out in two regions, i.e., heating and cooling, because the variation of material properties following a phase transformation in cooling is different in comparison with the case in heating, even at the same temperature. The variation of material properties following phase transformation is considered by the adjustment of specific heat and thermal expansion coefficient, and the distribution of residual stress in analysis is compared with that of experiment by previous study. In this study, simplified numerical procedures considering phase transformation, which based on a commercial finite element package was established through comparing with the experimental data of residual stress distribution by other researcher. To consider the phase transformation effect on residual stress relaxation, the transition of mechanical and thermal property such as thermal expansion coefficient and specific heat capacity was found by try and error method in this analysis. In addition to, since the transformation temperature changes by the kind and control of alloying elements, the steel with many kinds of transformation temperature were selected and the effect of transformation on stress releasement was investigated by the numerical procedures considering phase transformation.

• Journal of Information Technology Applications and Management
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• 제28권3호
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• pp.23-30
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• 2021

Korea currently provides long-term care benefits for the elderly with poor functionality, but most of the service providers are private businesses. This is the time when quality management of care services is required, which is just around the corner of the super-aged era. In this study, we would like to look at the case in which 'A company', which operates a long-term care institution, attempted to make voluntary changes ahead of social demands. The company tried to transform the social needs of quality management by judging them as opportunities, not threats, and establishing an integrated database of centers. First, the company processed data and built a cloud-based database system. Second, the company automatically linked data from existing systems for the efficiency of data utilization. Third, the company pursued visualization for the convenience of data utilization. This allowed the company to make data-driven strategic decisions internally. This is expected to increase sales as it will soon lead to securing new customers and pioneering new markets. It is also significant in that it can provide best practices for the long-term care industry.