• 한국통신학회논문지
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• 제18권8호
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• pp.1213-1225
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• 1993

하이퍼미디어 시스템은 멀티미디어 정보를 검색하고 제시하기 위하여 링크를 이용한 브라우징과 탐색항해 도구를 이용한다. 본 연구에서 설계·구현한 시스템은 보다 효율적인 탐색항해를 지원하기 위하여 계층적 그룹과 지역 맵 도구를 제공한다. 특히, 클러스터링 기법을 적용하여 클러스터 트리를 형성하고 이를 이용하여 항해시 필요한 지식을 제공하는 방법을 제 안하고 있다. 또한 탐색 과 브라우징 기능을 통합함으로써 하이퍼미디어 시스템의 정보검색기능과 사용자 인터페이스를 높이도록 설계하였다. 본 하이퍼미디어시스템을 백과사전, 참고문헌정보, 전자사전, 전자책등의 분야에 적용할 수 있다.

• 한국물환경학회지
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• 제32권3호
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• pp.281-290
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• 2016

In the northernmost basin of the Bukhan River, pollution sources can have a concentrated distribution. In these basins, small streams show low flow with various and rapid water quality change in low pollutants load. Therefore, a water quality improvement plan of small streams and main stem will be necessary to establish the characteristics of small streams. This study selected a representative Hwacheon-gun in the northernmost basin of the Bukhan River. Hydro analysis was performed with GIS tools using DEM. A total of 152 small streams were listed. A total of 51 survey locations were selected after applying the selection criteria. Flow rate and water qualities were investigated. Pollution sources and pollutants loads were calculated for each basin. Pollution grade and typological classification were performed by cluster analysis using standardized environmental condition factors. As a result, G04, G01, H01 locations were found to have the worst pollution grades whereas J01, P01, and P02 had less pollution. Typological analyses were able to classify six types for the surveyed small streams. An effective water quality improvement plan was obtained based on the results of pollution grade and typological analysis using environmental condition factors of this study.

• 한국가정과교육학회지
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• 제13권3호
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• pp.35-57
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• 2001

The purposes of this study were to investigate the current status on stating a summary of assessments in the practical arts education and to analyze the problem and find out the reformation strategy for them. To achieve these purposes. 180 teachers working in all elementary schools located in Daegu-city was selected by systematic cluster sampling method. The data were collected by using the mailed questionnaire developed by the researcher, and there was a response rate of 91.7%. Findings showed that it was not realized the valid and reliable stating a summary of assessments because it was not fixed throughly in the elementary school. So many teachers had difficulties in assessing the practical arts subject and stating a summary of assessments. They used the computer programs of CMI(Computer Management Instruction) . Black Box. SA(Stand Along) for stating a summary of assessments. It was recommended that valid and reliable criteria of stating a summary of assessments should provided, and on-the-job training on the developing and selecting a good tools for stating a summary of assessments should required. And. it was also required that the various codes of stating a summary of assessments should developed. and the various materials. equipments. and systems should provided for teachers.

• 한국정밀공학회지
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• 제30권3호
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• pp.260-265
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• 2013

To increase the machine accuracy by improving the stiffness of spindle bearings, preload was applied to the spindle bearings. The methods of fixed position preload, convertible preload, constant pressure preload, and variable preload are used to apply the preload to the spindle bearing. The previous studies performed by the author of this study were variable preload methods using rubber pressure and centrifugal force based on mechanical systems. This study proposed a toggle joint mechanism that could be applied to variable preload method using centrifugal force and rubber pressure to increase the preload. Also, a finite element analysis was conducted to predict the deformation of the rubber and change of the preload. And the analysis results showed that the preload by the device using rubber pressure only was increased by the toggle joint mechanism using rubber pressure.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제14권5호
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• pp.1886-1908
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• 2020

With the technical advances, the amount of big data is increasing day-by-day such that the traditional software tools face a burden in handling them. Additionally, the presence of the imbalance data in big data is a massive concern to the research industry. In order to assure the effective management of big data and to deal with the imbalanced data, this paper proposes a new indexing algorithm for retrieving big data in the MapReduce framework. In mappers, the data clustering is done based on the Sparse Fuzzy-c-means (Sparse FCM) algorithm. The reducer combines the clusters generated by the mapper and again performs data clustering with the Sparse FCM algorithm. The two-level query matching is performed for determining the requested data. The first level query matching is performed for determining the cluster, and the second level query matching is done for accessing the requested data. The ranking of data is performed using the proposed Monarch chaotic whale optimization algorithm (M-CWOA), which is designed by combining Monarch butterfly optimization (MBO) [22] and chaotic whale optimization algorithm (CWOA) [21]. Here, the Parametric Enabled-Similarity Measure (PESM) is adapted for matching the similarities between two datasets. The proposed M-CWOA outperformed other methods with maximal precision of 0.9237, recall of 0.9371, F1-score of 0.9223, respectively.

• Child Health Nursing Research
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• 제23권2호
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• pp.207-218
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• 2017

Purpose: The purpose of this study was to investigate parents' perceptions and attitudes regarding a screening test for and subsequent management of students' emotional and behavioral problems. Methods: A descriptive research design was used, and included disproportional stratified and cluster random sampling. The sample comprised 223 parents of elementary, middle, and high school students. Data were analyzed using descriptive statistics, Chi-squared test, and ANOVA with SPSS/WIN 21.0. Results: Overall, parents responded that they knew of the goals, types, and tools of screening tests for students' emotional and behavioral problems. In total, 64.6% of parents reported having information for the screening test in advance. Only 13.5%(n=30) of students had emotional and behavioral problems in the last year. Among these students, 56.7%(n=17) were referred to mental health facilities but only 29.4%(n=5) of them received ongoing management from these facilities. Conclusion: These findings suggest that parents should receive information about the screening test for and subsequent management of students' emotional and behavioral problems. Health professionals need to build strategies to provide ongoing management for students who have emotional and behavioral problems.

• Journal of Power Electronics
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• 제14권5호
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• pp.946-956
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• 2014

Cascaded H-Bridge (CHB) converters can be directly connected to medium-voltage grids without using transformers and they possess the advantages of large capacity and low harmonics. They are significant tools for providing grid connections in large-capacity renewable energy systems. However, the reliability of a grid-connected CHB converter can be seriously influenced by the number of power switching devices that exist in the structure. This paper proposes a fault-tolerant control strategy based on double zero-sequence voltage injection and DC voltage optimization to improve the reliability of star-connected CHB converters after one or more power units have been bypassed. By injecting double zero-sequence voltages into each phase cluster, the DC voltages of the healthy units can be rapidly balanced after the faulty units are bypassed. In addition, optimizing the DC voltage increases the number of faulty units that can be tolerated and improves the reliability of the converter. Simulations and experimental results are shown for a seven-level three-phase CHB converter to validate the efficiency and feasibility of this strategy.

• 기술혁신학회지
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• 제9권4호
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• pp.715-739
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• 2006

본 논문은 Carlsson and Stankielvicz(1991)에 의해 처음으로 소개된 기술시스템(Technological Systems; TSs) 의 개념을 발전시키고, 이를 우리나라 평판 프린팅 기술에 적용하였다. 특히 평판 프린팅 기술이 생산 공정기술로서 차세대 기술인 생명공학기술, 정보기술, 환경기술, 나노기술 등과 결합하면서, 하나의 기술시스템으로 창출 및 진화되는 동태적 과정을 분석하였다. 연구결과, 평판 프린팅 기술이라는 특정기술에 초점을 맞춘 기술시스템 접근방법이 국가혁신시스템, 지역혁신시스템, 산업클러스터 등 기존의 접근방법들이 추구하는 정책 목표를 보다 효과적으로 달성시킬 수 있음을 보이고, 이를 하나의 대안적 정책개념으로 제안하였다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제10권10호
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• pp.4933-4956
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• 2016

Use-After-Free (UAF) is a common lethal form of software vulnerability. By using tools such as Web Browser Fuzzing, a large amount of samples containing UAF vulnerabilities can be generated. To evaluate the threat level of vulnerability or to patch the vulnerabilities, automatic deduplication and exploitability determination should be carried out for these samples. There are some problems existing in current methods, including inadequate pertinence, lack of depth and precision of analysis, high time cost, and low accuracy. In this paper, in terms of key dangling pointer and crash context, we analyze four properties of similar samples of UAF vulnerability, explore the method of extracting and calculate clustering eigenvalues from these samples, perform clustering by fast search and find of density peaks on a large number of vulnerability samples. Samples were divided into different UAF vulnerability categories according to the clustering results, and the exploitability of these UAF vulnerabilities was determined by observing the shape of class cluster. Experimental results showed that the approach was applicable to the deduplication and exploitability determination of a large amount of UAF vulnerability samples, with high accuracy and low performance cost.

• International Journal of Advanced Culture Technology
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• 제10권3호
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• pp.253-262
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• 2022

The purpose of this study is to investigate the influence of golf participants' major hitting factors on their consumption behavior characteristics and golf consumption behavior. To achieve this objective, the study subjects were set as the population aged 20 years or older who use golf courses and driving ranges in Gwangju Metropolitan City and Jeollanam-do, and then 158 males and 172 females using cluster random sampling. A total of 300 persons were selected as the study subjects. The survey tool was the questionnaire method, and among the tools that had already been used to verify the reliability and validity of the questionnaire in domestic and foreign previous studies, it was reused or modified or supplemented according to the variables of this study. The collected data were winter-processed according to the purpose of analysis using the SPSS statistical program as follows. The results obtained through this process are as follows. First, it was found that the major players participating in golf had partial differences in the characteristics of golf consumption behavior. Second, it was found that the major hitters participating in golf had a partial difference in their golf consumption behavior. Third, it was found that the golf consumption behavior characteristics of golf participants partially affected the golf consumption behavior.