• 산업경영시스템학회지
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• 제40권4호
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• pp.147-153
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• 2017

The mortality rate in industrial accidents in South Korea was 11 per 100,000 workers in 2015. It's five times higher than the OECD average. Economic losses due to industrial accidents continue to grow, reaching 19 trillion won much more than natural disaster losses equivalent to 1.1 trillion won. It requires fundamental changes according to industrial safety management. In this study, We classified the risk of accidents in industrial complex of Ulju-gun using spatial analytics and data mining. We collected 119 data on accident data, factory characteristics data, company information such as sales amount, capital stock, building information, weather information, official land price, etc. Through the pre-processing and data convergence process, the analysis dataset was constructed. Then we conducted geographically weighted regression with spatial factors affecting fire incidents and calculated the risk of fire accidents with analytical model for combining Boosting and CART (Classification and Regression Tree). We drew the main factors that affect the fire accident. The drawn main factors are deterioration of buildings, capital stock, employee number, officially assessed land price and height of building. Finally the predicted accident rates were divided into four class (risk category-alert, hazard, caution, and attention) with Jenks Natural Breaks Classification. It is divided by seeking to minimize each class's average deviation from the class mean, while maximizing each class's deviation from the means of the other groups. As the analysis results were also visualized on maps, the danger zone can be intuitively checked. It is judged to be available in different policy decisions for different types, such as those used by different types of risk ratings.

• Journal of Information Science Theory and Practice
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• 제7권3호
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• pp.6-20
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• 2019

Learning analytics, or educational data mining, is an emerging field that applies data mining methods and tools for the exploitation of data coming from educational environments. Learning management systems, like Moodle, offer large amounts of data concerning students' activity, performance, behavior, and interaction with their peers and their tutors. The analysis of these data can be elaborated to make decisions that will assist stakeholders (students, faculty, and administration) to elevate the learning process in higher education. In this work, the power of Excel is exploited to analyze data in Moodle, utilizing an e-learning course developed for enhancing the information computer technology skills of school teachers in primary and secondary education in Greece. Moodle log files are appropriately manipulated in order to trace daily and weekly activity of the learners concerning distribution of access to resources, forum participation, and quizzes and assignments submission. Learners' activity was visualized for every hour of the day and for every day of the week. The visualization of access to every activity or resource during the course is also obtained. In this fashion teachers can schedule online synchronous lectures or discussions more effectively in order to maximize the learners' participation. Results depict the interest of learners for each structural component, their dedication to the course, their participation in the fora, and how it affects the submission of quizzes and assignments. Instructional designers may take advice and redesign the course according to the popularity of the educational material and learners' dedication. Moreover, the final grade of the learners is predicted according to their previous grades using multiple linear regression and sensitivity analysis. These outcomes can be suitably exploited in order for instructors to improve the design of their courses, faculty to alter their educational methodology, and administration to make decisions that will improve the educational services provided.

• 한국수자원학회논문집
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• 제53권4호
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• pp.285-291
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• 2020

이 연구에서는 Noah 3.3 지면모형을 이용하여 표층과 근역층(root-zone)의 토양함수비를 추정하고, 이를 위성기반 및 재분석 토양수분자료와 비교·검증하였다. 먼저, Noah 3.3 지면모형으로부터 추정한 4개 토양층 중 지면에 가까운 3개층(즉, 표층으로부터 1 m 깊이까지) 토양함수비를 이용하여 3개층의 깊이 가중평균값을 근역층 토양 함수비로 정의하였다. 이렇게 Noah 3.3 지면모형으로 추정한 토양함수비를 위성기반 표층 토양 함수비(European Space Agency Climate Change Initiatives Soil Moisture Product v04.4, ESA CCI SM v04.4)와 ERA-interim 재분석 표층 및 근역층 토양함수비와 비교·검증하였다. 또한, 전지구의 주요 5개 유역(Yangtze, Mekong, Mississippi, Murray-Darling, Amazon)에 대해 Gravity Recovery and Climate Experiment (GRACE) 관측 Total Water Storage Anomaly (TWSA) 와 TWS Change (TWSC)를 이용하여 비교·검증하였다. Noah 3.3 지면모형으로 산정한 토양수분 자료는 동아시아 지역과 남아시아 지역, 호주, 북미와 남미 등 대부분의 아시아·태평양지역에서 높은 아노말리 상관관계를 보였으며, 5개 유역에서 호주의 머레이-달링(Murray-Darling)유역에서 다소 낮은 상관관계를 보였으나, 나머지 4개 유역에서는 대체로 높은 상관성을 보였다. Noah 3.3 지면모형은 준실시간 토양수분 모의가 가능하기 때문에 이에 기반한 가뭄감시가 가능하며, 선제적 가뭄 대응 대책 마련에 활용성이 클 것으로 기대된다.

• 지식경영연구
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• 제24권3호
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• pp.95-125
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• 2023

항공산업의 급격한 성장으로 인해 많은 항공사가 생기면서 고객들이 항공사를 선택할 때 고려하는 요소가 늘어나고 있다. 이에 따라 항공사는 고품질의 서비스와 차별화된 경험적 가치를 제공하여 고객가치를 높이고 있다. 초기 고객가치 연구는 제품 및 서비스에 대한 효용성의 관점에서 비용과 편익 간의 상충관계로 간주하고 실용적 가치 중심으로 이루어졌지만, 최근에는 경험적 측면의 가치의 중요성이 주목받았다. 그러나 경험적 측면의 가치는 제품이나 서비스 상황에 따라 고객가치를 구성하는 요소가 변화되기 때문에 제품이나 서비스에 대한 고객의 선호도를 충분히 나타내는 특정 맥락에서 조사해야 한다. 또한, 고객가치는 고객이 의사결정을 내릴 때 큰 영향을 미치므로 항공사는 고객가치를 구성하는 요소를 정확하게 이해하는 것이 필요하다. 따라서 본 연구에서는 항공 전문 웹사이트인 스카이트랙스(Skytrax)에서 고객이 작성한 리뷰와 평점을 수집하고 BERTopic 모델을 활용하여 고객가치에 대한 요소를 도출하였다. 분석 결과, 항공사에서 고객가치를 구성하는 9가지 요소를 파악하였으며 이 중 6가지 요소가 고객 만족도와 영향을 미침을 확인하였다. 이를 통해 본 연구는 고객가치의 세분화된 파악을 가능하게 하는 새로운 방법론을 제안하고, 항공사에 구체적인 서비스 품질 향상을 위한 방향을 제시한다는 의의와 시사점을 가진다.

• Korean Journal of Radiology
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• 제22권7호
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• pp.1213-1224
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• 2021

Objective: To develop a machine learning (ML) pipeline based on radiomics to predict Coronavirus Disease 2019 (COVID-19) severity and the future deterioration to critical illness using CT and clinical variables. Materials and Methods: Clinical data were collected from 981 patients from a multi-institutional international cohort with real-time polymerase chain reaction-confirmed COVID-19. Radiomics features were extracted from chest CT of the patients. The data of the cohort were randomly divided into training, validation, and test sets using a 7:1:2 ratio. A ML pipeline consisting of a model to predict severity and time-to-event model to predict progression to critical illness were trained on radiomics features and clinical variables. The receiver operating characteristic area under the curve (ROC-AUC), concordance index (C-index), and time-dependent ROC-AUC were calculated to determine model performance, which was compared with consensus CT severity scores obtained by visual interpretation by radiologists. Results: Among 981 patients with confirmed COVID-19, 274 patients developed critical illness. Radiomics features and clinical variables resulted in the best performance for the prediction of disease severity with a highest test ROC-AUC of 0.76 compared with 0.70 (0.76 vs. 0.70, p = 0.023) for visual CT severity score and clinical variables. The progression prediction model achieved a test C-index of 0.868 when it was based on the combination of CT radiomics and clinical variables compared with 0.767 when based on CT radiomics features alone (p < 0.001), 0.847 when based on clinical variables alone (p = 0.110), and 0.860 when based on the combination of visual CT severity scores and clinical variables (p = 0.549). Furthermore, the model based on the combination of CT radiomics and clinical variables achieved time-dependent ROC-AUCs of 0.897, 0.933, and 0.927 for the prediction of progression risks at 3, 5 and 7 days, respectively. Conclusion: CT radiomics features combined with clinical variables were predictive of COVID-19 severity and progression to critical illness with fairly high accuracy.

• Journal of Multimedia Information System
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• 제5권3호
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• pp.195-200
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• 2018

Recently, as the sensor and big data analysis technology have been developed, there have been a lot of researches that analyze the purchase-related data such as the trajectory information and the stay time. Such purchase-related data is usefully used for the purchase pattern prediction and the purchase time prediction. Because it is difficult to find periodic patterns in large-scale human data, it is necessary to look at actual data sets, find various feature patterns, and then apply a machine learning algorithm appropriate to the pattern and purpose. Although existing papers have been used to analyze data using various machine learning methods, there is a lack of statistical analysis such as finding feature patterns before applying the machine learning algorithm. Therefore, we analyze the purchasing data of Songjeong Maeil Market, which is a data gathering place, and finds some characteristic patterns through statistical data analysis. Based on the results of 1, we derive meaningful conclusions by applying the machine learning algorithm and present future research directions. Through the data analysis, it was confirmed that the number of visits was different according to the regional characteristics around Songjeong Maeil Market, and the distribution of time spent by consumers could be grasped.

• 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.

• 한국문헌정보학회지
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• 제49권1호
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• pp.173-200
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• 2015

이 연구는 J도 도립도서관의 대출과 운영현황을 조사 분석하여 향후 발전방안을 모색하는데 있다. 이를 위해 도서관 이용증 발급자 30,072명과 대출건수(2012~2013년) 705,447건을 분석하였으며, 도서관 발전계획 및 이용자 만족도를 조사하여 이를 비교분석하였다. 분석방법은 SPSS 21.0을 사용하였다. 이를 통해 도립도서관 이용자의 도서관 이용 행태 및 자료 이용 패턴 등을 확인하였으며, 분석 결과를 기반으로 도립도서관의 발전방안을 제시하였다.

• Journal of Computing Science and Engineering
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• 제7권1호
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• pp.1-20
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• 2013

Over the past generation, data warehousing and online analytical processing (OLAP) applications have become the cornerstone of contemporary decision support environments. Typically, OLAP servers are implemented on top of either proprietary array-based storage engines (MOLAP) or as extensions to conventional relational DBMSs (ROLAP). While MOLAP systems do indeed provide impressive performance on common analytics queries, they tend to have limited scalability. Conversely, ROLAP's table oriented model scales quite nicely, but offers mediocre performance at best relative to the MOLAP systems. In this paper, we describe a storage and indexing framework that aims to provide both MOLAP like performance and ROLAP like scalability by essentially combining some of the best features from both. Based upon a combination of R-trees and bitmap indexes, the storage engine has been integrated with a robust OLAP query engine prototype that is able to fully exploit the efficiency of the proposed storage model. Specifically, it utilizes an OLAP algebra coupled with a domain specific query optimizer, to map user queries directly to the storage and indexing framework. Experimental results demonstrate that not only does the design improve upon more naive approaches, but that it does indeed offer the potential to optimize both query performance and scalability.

• Agribusiness and Information Management
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• 제11권1호
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• pp.1-9
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• 2019

This research intends to propose the methodology for analyzing the current trends of agriculture, which directly connects to the survival of the nation, and through this methodology, identify the agricultural trend of Korea. Based on the relationship between three types of data - policy reports, academic articles, and news articles - the research deducts the major issues stored by each data through LDA, the representative topic modeling method. By comparing and analyzing the LDA results deducted from each data source, this study intends to identify the implications regarding the current agricultural trends of Korea. This methodology can be utilized in analyzing industrial trends other than agricultural ones. To go on further, it can also be used as a basic resource for contemplation on potential areas in the future through insight on the current situation. database of the profitability of a total of 180 crop types by analyzing Rural Development Administration's survey of agricultural products income of 115 crop types, small land profitability index survey of 53 crop types, and Statistics Korea's survey of production costs of 12 crop types. Furthermore, this research presents the result and developmental process of a web-based crop introduction decision support system that provides overseas cases of new crop introduction support programs, as well as databases of outstanding business success cases of each crop type researched by agricultural institutions.