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RDF 질의 처리 성능 향상을 위한 실체 뷰 선택 기법
박재열(Jaeyeol Park),윤상원(Sangwon Yoon),최기태(Kitae Choi),임종태(Jongtae Lim),이병엽(Byoungyup Lee),신재룡(Jaeryong Shin),복경수(Kyoungsoo Bok),유재수(Jaesoo Yoo) 한국콘텐츠학회 2015 한국콘텐츠학회논문지 Vol.15 No.12
시맨틱 웹의 발전과 함께 RDF 데이터에 대한 사용이 증가되고 있다. RDF 데이터는 트리플로 구성되어 있으며 질의 처리 시 높은 조인 비용이 요구된다. 실체 뷰는 질의 처리 비용을 감소시키는 기법으로 알려져 있다. 실체 뷰는 질의 처리의 결과 또는 중간 결과를 저장 공간 내부에 물리적으로 저장하여 질의 처리시 전체 데이터베이스의 접근이 아닌 실체 뷰의 접근으로 질의를 처리한다. 본 논문에서는 이를 해결하기 위해 의사 결정 트리를 사용하여 실체 뷰를 선택한다. 제안하는 기법은 의사 결정 트리를 통해 질의 처리시간뿐만 아니라 실체 뷰의 크기 및 유지비용을 고려한다. 성능평가를 통해 제안하는 기법이 기존 기법에 비해 제한된 저장 공간에서의 실체 뷰는 증가하였고 동일 개수의 실체 뷰의 유지비용은 감소함을 보인다. With the development of the semantic web, a large amount of data being produced nowadays is in RDF format. RDF is represented by a triple. An RDF database consisting of triples requires the high cost of join query processing. Materialized view is known as a scheme to reduce the query processing cost by accessing materialized views without accessing the database. It is physically stored the results or the intermediate results of the query processing in a storage area. In this paper, we propose a materialized view selection scheme by using decision tree to solve such a problem. The decision tree considers the size and maintenance costs of the materialized view as well as the profit of query response times. It is shown through performance evaluation that the proposed scheme increases the number of materialized views in the limited storage space and decreases the update rates of the materialized views.
SunMi Kim,JaeWoo Jung,InWon Park,ChulMin Ahn,YuIl Kim,KwangHa Yoo,EunMi Chun,JiYe Jung,YoungSik Park,JuHeon Park,JaeYeol Kim,Korean Smoking Cessation Study Group 대한신경정신의학회 2016 PSYCHIATRY INVESTIGATION Vol.13 No.2
Objective-As mental health problems may play an important role in initiating and maintaining cigarette smoking in females and there are an increasing number of female smokers, we evaluated the relationship between smoking status and mental health problems including depression and suicide ideation in women in Korea. Methods-We analyzed the 5-year cumulative data (19 years of age or older, n=32,184) from the Korean National Health and Nutrition Examination Survey (KNHANES) conducted from 2008 to 2012. Logistic regression analyses were used to evaluate associations between cigarette smoking status and mental health parameters while controlling for potentially confounding variables. Results-Among current smokers, females showed higher lifetime prevalence in having a depressive episode, a doctor-diagnosed major depression, a current diagnosis of depression, or receiving treatment for depression in comparison with males. In addition, females were more likely to report on having a depressive episode, suicidal ideation and attempts, and psychiatric counselling within the previous year, as compared to males. Female former smokers showed intermediate characteristics in parameters of mental health status within the previous year, ranking between lifetime non-smokers and the current smokers. Conclusion-Identifying the factors related to mental health status among current smokers can increase opportunities for an early intervention and help reduce the prevalence of smoking and increase smoking cessation rates particularly in females. Developing adaptive coping strategies other than smoking in female youth is potentially important in reducing the initiation of smoking.
NAUT를 적용한 자동차용 Brake Pad의 결함검출
김재열(Jaeyeol Kim),박인우(Inwoo Park),최승현(Seunghyun Choi),한재호(Jaeho Han),김훈조 한국자동차공학회 2011 한국자동차공학회 지부 학술대회 논문집 Vol.2011 No.9
The NAUT(Non-contact Air coupled Ultrasonic Testing) technique allows non-contact ultrasonic testing in air. If the NAUT technique can be applied, not only ultrasonic testing in air with no couplant would be possible, but also the stable transmission and reception of ultrasonic waves, which would thus enable ultrasonic testing of hot or cold materials, or rough surfaces of specimens that could not be tested with conventional-contact ultrasonic testing techniques. By trying NAUT for Brake lining pad specimens, the applicability of NAUT in these areas was observed, and the results from the waveforms of parts of the specimens were analyzed. For the Brake lining pad specimen, the ultrasonic transmittance was highest at the part, regardless of the thickness and location of the specimen. These findings confirmed the practicality of NAUT.
가속 전략을 통한 적응형 순항 제어 시스템의 연비 향상 제어 알고리즘 개발
염재열(Jaeyeol Yeom),박창우(Changwoo Park),이형철(Hyeongcheol Lee) 한국자동차공학회 2014 한국자동차공학회 학술대회 및 전시회 Vol.2014 No.11
This paper presents an adaptive cruise control algorithm to improve fuel efficiency. The algorithm controls vehicle velocity by considering the vehicle acceleration depending on the average velocity to a preceding vehicle. By previous study, the study of the ACC system has dealt with only performance of stability. However, based on vision sensor, this study doesn’t only deal with stability of the ACC system but also consider fuel efficiency. This algorithm is simulated using Carsim<SUP>®</SUP> simulator with vision sensor for verifying its effectiveness.
통계패키지 사용성 평가를 통한 한국형 통계패키지 개발 가능성 모색
이재열 ( Jaeyeol Yee ),신인철 ( Inchol Shin ),이영조 ( Youngjo Lee ),김청택 ( Cheongtag Kim ),박원호 ( Won-ho Park ),진윤아 ( Yoona Chin ),김혜진 ( Hyejin Kim ) 한국조사연구학회 2021 조사연구 Vol.22 No.2
사회과학연구에서 통계분석을 적용한 양적 접근이 활성화됨에 따라, 많은 연구자들이 다양한 범용통계패키지를 이용하고 있다. 다만 일부 통계패키지를 제외하고는 대부분의 연구자는 외국산 유료 소프트웨어를 이용하고 있을 뿐만 아니라, 학습을 위해 많은 시간과 비용을 지불하고 있다. 이 연구는 한국형 통계패키지 개발을 목표로 추진된 융·복합 연구에서 진행한 통계패키지 사용성 평가결과를 중심으로 기존 범용통계패키지의 특성을 탐색해보았다. 그리고 웹기반 통계패키지를 새롭게 개발하여 기존 범용통계패키지와의 비교를 통해 개선사항을 확인하였다. 이와 더불어 평가자들에게 사용 의향성을 확인하여 초급자용 통계패키지를 개발하고자 할 경우 학습용이성과 효율성, 그리고 이해용이성이 매우 중요한 방향성임을 확인하였다. 이러한 결과는 앞으로 통계패키지를 개선하거나 새롭게 개발할 때 참고할 기준이 될 것으로 기대한다. In social science research, a quantitative approach applying statistical analysis is being invigorated, and many researchers are using various general-purpose statistical packages. However, with the exception of some statistical packages, most of them are charged foreign software. And users are paying a lot of time and money for learning. Under aimed at developing a Korean statistical package, this study explored the characteristics of the general-purpose statistical package and newly developed web-based statistical package, based on the results of the usability evaluation of the statistical package. By evaluating the use intention of newly developed web-based statistical package we found that learning ease, efficiency, and ease of understanding should be considered when developing software for beginners. These results are expected to serve as a reference for other developers to improve or develop new statistical packages in the future.