• Smart Structures and Systems
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• 제17권6호
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• pp.1017-1030
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• 2016

This study focuses on the system identification of reinforced concrete bridges using vector autoregressive model (VAR). First, the time series output response from a bridge establishes the autoregressive (AR) models. AR models are one of the most accurate methods for stationary time series. Burg's algorithm estimates the autoregressive coefficients (ARCs) at p-lag by reducing the sum of the forward and the backward errors. The computed ARCs are assembled in the state system matrix and the eigen-system realization algorithm (ERA) computes: the eigenvector matrix that contains the vectors of the mode shapes, and the eigenvalue matrix that contains the associated natural frequencies. By taking advantage of the characteristic of the AR model with ERA (ARMERA), civil engineering can address problems related to damage detection. Operational modal analysis using ARMERA is applied to three experiments. One experiment is coupled with an artificial neural network algorithm and it can detect damage locations and extension. The neural network uses a specific number of ARCs as input and multiple submatrix scaling factors of the structural stiffness matrix as output to represent the damage.

• Child Health Nursing Research
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• 제28권3호
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• pp.208-217
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• 2022

Purpose: This study investigated childhood cancer survivors' behavior related to a healthy lifestyle during their survival period by comparing reports between childhood cancer survivors and their parents. Methods: In this comparative descriptive study, a survey was conducted with a 33-item questionnaire and one open-ended question about areas for improvement. The participants comprised 69 childhood cancer survivors and 69 of their parents, for a total of 138. Results: The total mean healthy lifestyle score, on a 4-point Likert scale, reported by childhood cancer survivors was 2.97, while that reported by their parents was 3.03. No significant differences in children's healthy lifestyles were found between childhood cancer survivors' and their parents' reports (t=0.86, p=.390). For the open-ended question, the main keywords based on the results of degree and eigenvector centrality were "exercise", "unbalanced diet", and "food". These keywords were present in both the children's and parents' responses. Conclusion: Obtaining information on childhood cancer survivors' healthy lifestyles based on reports from themselves and their parents provides meaningful insights into the improvement of health care management. The results of this study may be used to develop and plan healthy lifestyle standards to meet childhood cancer survivors' needs.

• 무역학회지
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• 제47권6호
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• pp.189-209
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• 2022

This study aims to analyze Latin America and the Caribbean papers published in Korea during the past 2000-2020 years. Through this study, it is possible to understand the main subject and direction of research in Korea's Latin America and the Caribbean area. As the research mythologies, this study uses the text mining and Social Network Analysis such as frequency analysis, several centrality analyses, and topic analysis. After analyzing the empirical results, there has been a tendency to change the key words and centrality coefficients between 2000-2010 and 2011-2020 years. During 2011-2020 years, the most frequent keywords were changed from Neoliberalism and culture to policy education, and economy related words. The degree and closeness centrality analyses appeared the higher frequency key words. However, the eigenvector centrality appeared very different from the order of frequency key words. The topic analysis shows that the culture, language, and Neoliberalism were the most important keywords during 2000-2010 years but economy, labor trade, industry, development became the most important keywords during 2011-2020 years in topics.

• Asia pacific journal of information systems
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• 제29권3호
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• pp.448-467
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• 2019

In a new age of smart tourism, free independent travelers (FITs) choose their travel routes in a more diversified and less predictable way with the aid of smart services. This paper focuses on the movements of Chinese outbound FITs in the U.S. in the year of 2018. 110 places to visit (destinations) extracted from 122 travel routes recommendations on Qyer.com, a major online travel community in China, are analyzed with social network analysis (SNA). Based on the results of SNA, employing degree centrality, eigenvector centrality, betweenness centrality, network visualization, and cluster diagram methods, some preferred cities and natural attractions outside city centers (i.e., New York City (NYC), Los Angeles, San Francisco, Washington D.C., and Niagara Falls) are identified. Moreover, it is found that NYC in the East and Los Angeles in the West play a major role in the movements of Chinese FITs. This study contributes to the body of knowledge on tourist destination movements and provides valuable implications for smart service development in the tourism and hospitality industry.

• 한국지리정보학회지
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• 제24권3호
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• pp.58-72
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• 2021

2021년 7월 UNCTAD가 우리나라를 선진국으로 분류할 정도로 우리나라가 발전하는 성과가 있었다. 그러나 급변하는 글로벌 경제에 대응하기 위해서는 국내 산업생태계를 연구하여 끊임없이 변화시키고 성장을 위한 전략을 마련해야 한다. 그 중 하나가 기업간 네트워크를 강화하는 것이며, 본 연구는 기업 간 거래 데이터 구득이 가능한 자동차산업을 대상으로 공간적인 산업 네트워크를 분석하였다. 데이터는 295개의 기업 데이터(노드)와 607개의 거래 관계 데이터(링크)를 활용하였다. 기업의 주소지를 지오코딩하여 공간상 분포를 확인한 결과, 자동차산업 관련 기업은 수도권과 동남권에 집중 분포하고 있었다. 연결중심성, 매개중심성, 근접중심성, 위세중심성 등을 통해 노드의 중요도를 측정하고, 밀도, 거리, 커뮤니티 탐지, 동류성 및 이류성을 파악하여 네트워크 구조를 확인하였다. 그 결과, 4가지 노드 중요도에서 상위 15위 기업은 완성차기업 중에서는 현대자동차, 기아자동차, 한국지엠 3개의 기업이 공통적으로 포함되고, 상위 15위 기업은 주로 수도권에 입지하고 있다. 규모 면에서 연결중심성과 매개중심성은 대부분 종업원 수가 1,000명 이상인 큰 기업이고, 근접중심성과 위세중심성은 완성차기업을 제외하면 대개 종업원 수가 500명 이하인 기업이 상위 15위 안에 포함되었다. 전체적인 네트워크의 구조는 밀도는 0.01390522, 노드 간 평균거리는 3.422481로 나타났으며, 빠른탐욕알고리즘으로 커뮤니티 탐지를 실시한 결과, 최종적으로 11개의 커뮤니티가 도출되었다.

• 농촌계획
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• 제23권2호
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• pp.43-54
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• 2017

When an age of low growth and population decline, population migration plays an important role in spatial structure of region. There have been many researches on migration and regional spatial structure. The purpose of this study is to examine the changes of Gwangju and Jeonnam region's spatial structure and central area using social network analysis methods. For analysis it was used that population and migration data and passenger OD(Origin and Destination) travel data released by Statistics Korea and Korea Transport Database(KTDB). Using Gephi 0.8.2, migration and passenger OD networks were visualized, and this describe network flow and density. The results of the network centrality analysis show that the most populated village is not always network center though population mass is an important factor of central places. The average eigenvector centrality of 2010 migration is the lowest during 2005-2015, and it means few regions have high centralities. When comparing migration and travel networks, travel data is more effective than migration data in determining the central location considering spatial functions.

• 한국조리학회지
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• 제24권2호
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• pp.34-43
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• 2018

The objective of this study was to acquire a general and text-based awareness and recognition of cruise food hygiene through big data analytics. For the purpose, this study collected data with conducting the keyword "food hygiene, cruise" on the web pages and news on Google, during October 1st, 2015 to October 1st, 2017 (two years). The data collection was processed by SCTM which is a data collecting and processing program and eventually, 899 kb, approximately 20,000 words were collected. For the data analysis, UCINET 6.0 packaged with visualization tool-Netdraw was utilized. As a result of the data analysis, the words such as jobs, news, showed the high frequency while the results of centrality (Freeman's degree centrality and Eigenvector centrality) and proximity indicated the distinct rank with the frequency. Meanwhile, as for the result of CONCOR analysis, 4 segmentations were created as "food hygiene group", "person group", "location related group" and "brand group". The diagnosis of this study for the food hygiene in cruise industry through big data is expected to provide instrumental implications both for academia research and empirical application.

• 한국정보과학회:학술대회논문집
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• 한국정보과학회 2011년도 한국컴퓨터종합학술대회논문집 Vol.38 No.1(C)
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• pp.191-194
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• 2011

문서를 이루는 단어들의 빈도수가 지수법칙(power law)를 따른다는 지프의 법칩(Zipf's law)이 있다. 이러한 단어분포를 고려하여 문서의 토픽을 찾아내는 기계학습법이 디리쉴레 프로세스(Dirichlet process) 이다. 이를 발전시켜서 데이터의 잠재 요인(latent factor)들을 베이즈 확률모델에 기반한 샘플링 바탕으로 찾는 방법이 인디언 뷔페 과정(Indian buffet process) 이다. 우리는 25가지의 특징(feature)들에 대한 점수(rating)들이 볼드(blood oxygen dependent level) 신호와 함께 주어지는 PBAIC 2007 데이터에 주성분 분석법(principal component analysis)를 적용했다. PBAIC 2007 데이터는 비디오 게임을 수행하며 기능적뇌영상(functional magnetic resonance imaging, fMRI) 촬영을 하여 얻어진 공개데이터이다. 우리의 연구에서는 주성분 분석법을 이용하여 10개의 독립 성분(independent component)들을 찾았다. 그리고 1.75초 마다 촬영된 BOLD 신호와 10개의 고유벡터(eigenvector)들간의 내적을 취하여 가중치(weight)를 구하였다. 성분들의 가중치를 낮은 순서로 정렬함으로써 각 시간마다 주도적으로 영향을 미치는 성분들을 알아낼 수 있었다.

• 정보관리연구
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• 제37권2호
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• pp.33-50
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• 2006

본 연구에서는 하이퍼 링크 구조를 이용한 웹 검색 알고리즘에 대해 살펴 본 후 페이지 품질을 측정하기 위해 웹의 하이퍼 구조를 이용하고 있는 알고리즘인 HITS와 PageRank를 분석하였다. 이어서 이들 방법을 이용한 검색 엔진인 Google과 Ask.com을 검색 알고리즘의 특성을 기준으로 분석하였다. 이런 연구는 미래의 웹 문서의 중요도를 평가하는 데 기초자료로 활용할 수 있으며, 웹 정보검색의 검색성능을 향상시키는 시스템 개발에 도움이 될 수 있을 것이라 생각한다.

• 전자공학회논문지CI
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• 제41권5호
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• pp.33-40
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• 2004

본 논문에서는 웨이블릿 압축을 이용하여 얼굴 데이터베이스를 구축하고, 주성분 분석(Principal Component Analysis : PCA) 알고리듬을 이용하여 얼굴 인식률을 비교한다. 일반적인 얼굴인식 방법은 정규화된 크기를 이용하여 데이터베이스를 구축하고, 얼굴 인식을 한다. 제안된 방법은 정규화된 크기(92×112)의 영상을 웨이블릿 압축으로 1단계, 2단계, 3단계로 변환하고 데이터베이스를 구축한다. 입력 영상도 웨이블릿으로 압축하고 PCA 알고리듬으로 얼굴인식 실험을 하였다 실험을 통하여 제안된 방법은 기존 얼굴영상의 정보를 축소할 뿐만 아니라 처리속도도 향상되었다. 또한 제안된 방법은 원본 영상이 99.05%, 1단계 99.05%, 2단계 98.93%, 3단계 98.54% 정도의 인식률을 보였으며, 대량의 얼굴 데이터베이스를 구축하여 얼굴인식을 하는데 가능함을 보였다.