• 한국사회복지학
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• 제62권4호
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• pp.171-192
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• 2010

본 연구는 장애인의 직업재활성과에 영향을 미치는 개인적, 조직적 특성을 밝힘으로써 장애인 직업재활사업의 발전을 위한 실천적 함의를 제공하는데 목적이 있다. 분석을 위해 2009년 서울시에서 운영비를 지원하고 있는 장애인 직업재활시설 내 장애인과 시설에 대한 조사결과를 활용하였으며, 임금수준을 장애인의 직업재활성과로 간주하여 분석하였다. 분석방법으로는 직업재활성과의 개인효과와 조직효과를 구분하기 위해 위계선형모형(Hierarchical Linear Model)을 사용하였다. 분석결과, 장애인 직업재활시설 간 차이가 장애인의 임금수준을 설명하는 비중이 유의하게 높았으며, 개인특성과 조직특성의 상호작용효과를 분석한 결과 장애유형과 조직특성 변수 간의 상호작용효과가 유의한 것으로 나타났다. 정책적으로 장애인 직업재활사업의 성과를 높이기 위해 직업재활시설 간 격차를 줄이기 위한 노력이 필요하며, 장애유형 및 특성에 따라 시설운영에 있어 각별한 관심이 요구된다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제5권11호
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• pp.2068-2086
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• 2011

Based on the quincunx sub-sampling grid, the New Interleaved Hierarchical INTerpolation (NIHINT) method is recognized as a superior pyramid data structure for the lossless and progressive coding of natural images. In this paper, we propose a new image interpolation algorithm, Edge Adaptive Hierarchical INTerpolation (EAHINT), for a further reduction in the entropy of interpolation errors. We compute the local variance of the causal context to model the strength of a local edge around a target pixel and then apply three statistical decision rules to classify the local edge into a strong edge, a weak edge, or a medium edge. According to these local edge types, we apply an interpolation method to the target pixel using a one-directional interpolator for a strong edge, a multi-directional adaptive weighting interpolator for a medium edge, or a non-directional static weighting linear interpolator for a weak edge. Experimental results show that the proposed algorithm achieves a better compression bit rate than the NIHINT method for lossless image coding. It is shown that the compression bit rate is much better for images that are rich in directional edges and textures. Our algorithm also shows better rate-distortion performance and visual quality for progressive image transmission.

• Journal of Information Technology Applications and Management
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• 제17권4호
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• pp.19-38
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• 2010

This paper investigates the effect of stress on knowledge creation. The goal stress of resource inadequacy and job stress had negative influences on knowledge creation. However, the cohesion and mastery climate of team had positive influence on knowledge creation. Therefore this paper verifies the moderate role of the cohesion and mastery climate of team on the relationship between stress and knowledge creation. The model developed was tested using data collected from knowledge based industry with 375 members in 69 teams in 12 different firms. A Hierarchical Linear Model (HLM) was used to test the hypotheses generated from the model. Results show that job stress had a negative influence on knowledge creation as we expected but the goal stress didn't. The mastery climate of team affected knowledge creation positively and moderated the relationship between the goal stress and knowledge creation. Furthermore, the team cohesion had a positive influence on knowledge creation. The study provided some implications that practitioners should consider the stress when they design jobs for team members and suggest them the way to manage their job stress when they work.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제11권12호
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• pp.6017-6037
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• 2017

In a multi-resolution image encoding system, the image is encoded into a single file as a layer of bit streams, and then it is transmitted layer by layer progressively to reduce the transmission time across a low bandwidth connection. This encoding scheme is also suitable for multiple decoders, each with different capabilities ranging from a handheld device to a PC. In our previous work, we proposed an edge adaptive hierarchical interpolation algorithm for multi-resolution image coding system. In this paper, we enhanced its compression efficiency by adding three major components. First, its prediction accuracy is improved using context adaptive error modeling as a feedback. Second, the conditional probability of prediction errors is sharpened by removing the sign redundancy among local prediction errors by applying sign flipping. Third, the conditional probability is sharpened further by reducing the number of distinct error symbols using error remapping function. Experimental results on benchmark data sets reveal that the enhanced algorithm achieves a better compression bit rate than our previous algorithm and other algorithms. It is shown that compression bit rate is much better for images that are rich in directional edges and textures. The enhanced algorithm also shows better rate-distortion performance and visual quality at the intermediate stages of progressive image transmission.

• 한국정보과학회논문지:데이타베이스
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• 제31권2호
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• pp.132-139
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• 2004

범위 상위-$\kappa$ 질의는 질의 범위 내의 다차원 데이타 중 값 애트리뷰트를 기준으로 상위 k개의 레코드를 반환하는 질의로 공간 데이타베이스와 데이타 웨어하우스에서 분석을 위해 많이 사용되는 유용한 질의 형태이다. 이 논문에서는 계층 최대 R-트리의 선택적인 탐색을 통해 범위 상위-k 질의를 효과적으로 수행하는 기법을 제시한다. 이 기법은 단말 노드의 일부만을 접근하여 질의를 수행할 수 있으며, 질의 범위의 크기에 관계없이 거의 일정한 성능을 보인다. 또한 이 기법은 우선순위 큐를 효율적으로 관리함으로써 큐의 유지비용을 최소화하며, 기존 R-트리와 같은 팬아웃을 보장할 수 있다.

• 한국의류학회지
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• 제31권8호
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• pp.1168-1179
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• 2007

The objective of this research is to validate the BRQ(Brand Relationship Quality) Construct perceived by fashion product consumers. In order to establish and verify the BRQ scale, qualitative survey and quantitative survey were conducted together. 1592 copies of questionnaire were distributed to women in their 20s to 40s living in Seoul and other metropolitan areas from Dec. 26, 2005 to Jan. 8, 2006, and 723 copies of them were used for statistical data. Samplel(n=482)was used for empirical analysis, and sample2(n=241) was used for cross validity test. The data was analyzed using Exploratory Factor Analysis, Confirmatory Factor Analysis, and Pearson's Correlation Analysis. BRQ emerged from exploratory factor analysis as the hierarchical construct composed of six facets including 'self-connective attachment', 'symbol/mystery', 'trust', 'nostalgia', 'intimacy', and 'knowledge'. As the fit of this structural model was not good as a result of Confirmatory Factor Analysis, it was revised to have better fitting. Finally, empirical survey results indicate the hierarchical construct consisting of eight distinct BRQ facets including 'love/commitment', 'self-connection', 'symbol', 'mystery', 'trust', 'nostalgia', 'intimacy', and 'knowledge' as best representing the final 39item BRQ Scale. Reliability, construct validity, and cross validity of the construct were verified.

• Communications for Statistical Applications and Methods
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• 제28권1호
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• pp.59-79
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• 2021

Value at Risk (VaR) is one of the most common risk management tools in finance. Since a portfolio of several assets, rather than one asset portfolio, is advantageous in the risk diversification for investment, VaR for a portfolio of two or more assets is often used. In such cases, multivariate distributions of asset returns are considered to calculate VaR of the corresponding portfolio. Copulas are one way of generating a multivariate distribution by identifying the dependence structure of asset returns while allowing many different marginal distributions. However, they are used mainly for bivariate distributions and are not widely used in modeling joint distributions for many variables in finance. In this study, we would like to examine the performance of various copulas for high dimensional data and several different dependence structures. This paper compares copulas such as elliptical, vine, and hierarchical copulas in computing the VaR of portfolios to find appropriate copula functions in various dependence structures among asset return distributions. In the simulation studies under various dependence structures and real data analysis, the hierarchical Clayton copula shows the best performance in the VaR calculation using four assets. For marginal distributions of single asset returns, normal inverse Gaussian distribution was used to model asset return distributions, which are generally high-peaked and heavy-tailed.

• 한국보육지원학회지
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• 제20권2호
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• pp.83-103
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• 2024

Objective: This study aimed to investigate the effects of children's characteristics and childcare teachers' attributes on the frequency and level of imaginative play in two-year-old classrooms. Methods: The study involved 191 toddlers, their mothers, and 32 teachers from childcare centers. Toddler characteristics encompassed temperament along with demographic variables such as gender and age. Teacher' attributes related to play included playfulness, play-support belief, and interactions with toddlers. Data analysis was conducted using SPSS 22.0 and HLM 8.2 software, employing basic analysis, hierarchical linear analysis, and hierarchical regression analysis. Results: First, as toddlers' age increased, both the frequency and level of their imaginative play increased. Second, individual-level model analysis revealed a positive effect of toddlers' extroversion on the level of imaginative play. Third, the class-level model results indicated that teachers' emotions had a negative effect, whereas their encouragement positively influenced the level of imaginative play. Conclusion/Implications: The significance of this study lies in its utilization of a multilayered model analysis, which offers a more robust examination of variable influences by accounting for hierarchical data structures.

• 창의정보문화연구
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• 제6권1호
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• pp.41-48
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• 2020

공간 데이터를 표현하고 처리하기 위해 사분트리 또는 이분트리 등의 계층형 자료 구조가 사용되고 있다. 이분 트리를 선형적으로 표현하기 위해 기존에 제안된 S-트리는 이진 영역 이미지 데이터를 선형적인 이진 비트열로 표현하여 저장 공간을 크게 압축할 수 있는 장점이 있으나, 이미지의 해상도가 높아질수록 이진 비트열의 길이가 길어져 저장 공간이 늘어나고 탐색 성능이 저하되는 문제점이 발생한다. 본 논문에서는 포화 이진 트리 구조를 갖는 여러 개의 분할 이분트리를 계층적으로 구성하고 각 분할 이분트리를 2개의 선형적 이진 비트열로 표현하여 이미지 탐색에 필요한 범위를 축소하는 한편 이진 비트열 경로를 직접 탐색하지 않고 간단한 숫자 변환을 통해 수행하도록 하여 전체적인 탐색 성능을 개선하였다. 최악의 시공간 복잡도 분석에 의한 성능 평가를 통해 제안 방법이 기존의 방법에 비해 우수한 검색 성능과 공간 효율성을 보이는 것으로 분석되었다.

• Journal of Information Technology Applications and Management
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• 제9권1호
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• pp.85-96
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• 2002

Nowadays an information exchange on XML such as B2B electronic commerce is spreading. Therefore the systematic and stable management mechanism for storing the exchanged Information is needed. For this goal there are many research activities for connection between XML application and relational database. But because XML data have hierarchical structures and relational database can store only flat-structured data, we need to store XML data in object-oriented database that support hierarchical structure. Accordingly the modeling methodology for storing XML data in object-oriented database is needed. In order to build good quality application systems, modeling is an important first step. In 1997, the OMG adopted the UML as its standard modeling language. Since industry has warmly embraced UML, its popularity should become more important in the future. So a design methodology based on UML is need to develop efficiently XML applications. In this paper, we propose a unified design methodology for XML applications based on object- oriented database using UML. To this goal, first we introduce a XML modeling methodology to design W3C XML schema using UML and second we propose data modeling methodology for object-oriented database schema to store efficiently XML data in object-oriented databases.