• Proceedings of the Korea Water Resources Association Conference
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• 2018.05a
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• pp.288-288
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• 2018

점착성 유사는 응집 현상을 겪는 유사로, 응집 현상(Flocculation Process)는 응집 과정(Aggregation Process)와 파괴 과정(Breakup Process)의 경쟁으로 이루어진다고 여겨진다. 응집 현상을 통해 점착성 유사는 물과 점착성을 띠는 작은 입자들의 덩어리인 플럭(Floc)을 형성하여 흐름 내에서는 대부분이 플럭의 형태로 이동한다. 점착성 유사의 응집 모형 중 하나인 플럭 성장모형(Floc Growth Model, FGM)은 상미분 방정식으로 시간에 따른 플럭의 크기를 계산하는 모형이다. 응집과 파괴의 평형 상태에서 평균 입경을 얻는다. 이러한 FGM은 낮은 수치 계산 비용으로 합리적인 계산 결과를 얻을 수 있으며, 유사 이동 모형 혹은 흐름 모형과의 결합이 수월한 장점을 가진다. 또한, 닫힌 계(Closed System)에서 질량이 보존되는 특징이 있다. 반면, 결정론적인 특성을 띠면서 특정 플럭 크기만을 계산하기 때문에 점착성 유사의 입도 분포에 대한 정보를 얻을 수 없다. 결정론적 특성을 띠는 FGM에 추계학적 방법을 적용함으로써 특정 확률 분포형을 가지는 플럭의 입도 분포를 얻을 수 있다. 본 연구에서는 기 개발된 추계학적 FGM과 유사 이동 모형의 결합을 통해 변화하는 유수동역학적 조건에서 플럭의 입도 분포를 산정하고자 한다. 이전의 많은 실험실 실험 결과들은 부유가 발생한 상태를 유지하면서 수행되는 것으로, 특정 난류 특성(난류 소산 매개변수)와 특정 유사 농도 조건에서의 입도 분포를 얻는다. 그러나 하구부 및 하천의 하류는 조류의 영향을 받는 구간으로, 점착성 유사의 특성을 분석하기 위해서는 변화하는 유수동역학적 특성에 관한 고려가 필수적이라 할 수 있다. 결합된 점착성 유사 입도 분포 모형은 플럭의 침강과 재부유를 고려할 수 있는 특징을 가지며, 실측자료와의 비교를 통해 입도 분포를 합리적으로 모의하는 것으로 나타난다. 본 연구에서 개발된 점착성 유사 입도 분포 모형은 나아가 비점착성 유사의 입도 분포 모형과의 결합을 통해 두 종류의 유사가 혼재하는 구간에서도 합리적인 입도분포와 유사의 이동을 모의할 수 있을 것으로 예측된다.

• Proceedings of the Korea Water Resources Association Conference
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• 2015.05a
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• pp.637-637
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• 2015

2009년 미국에서 처음으로 스마트워터그리드의 개념이 도입된 이후로 국내외 국가 기관뿐만 아니라 민간 기업에서도 스마트워터그리드에 대한 관심이 높아지고 있다. 현재 스마트워터그리드는 IBM의 진출을 시작으로 Veolia, Suez 등 다국적 물관리 기업들이 사업을 추진 중이다. 국내의 ICT기술과 수자원시스템의 융합을 통하여 용수 수요 공급량을 실시간으로 파악하고 관리하여 수자원의 지역적 시간적 격차를 해소하는 스마트워터그리드 연구가 국내에서도 진행 중이다. 물관리 시장 주도권을 확보하기 위해 글로벌 물기업간 경쟁이 심화되고 있으며, 개별플랫폼을 구축 활용하여 신규기업의 물산업 진출을 가로막고 있는 실정이다. 이러한 상황에서 국외 물산업 시장 진출을 위하여 통합플랫폼 개발 및 체계적인 데이터 구조 설계가 필요하며, 본 연구는 스마트워터그리드를 운영하기 위해 여러 곳에 분산되어 관리 운영되어지고 있는 수자원 및 물관리 데이터의 통합을 위한 체계적인 데이터베이스 구조설계에 대한 연구를 수행하였다. 이에 본 연구에서는 스마트워터그리드 도메인 내에 주력하고 있는 통합데이터베이스 구조를 외부 데이터 마이닝과 연계하여 확장하는 구조로 현실적이고 단기적인 데이터 통합효과를 위해 ETL/데이터웨어하우스방식을 적용하여 데이터 통합을 추진하였다. 지자체간 분산되어 있는 데이터베이스간의 연동은 관련 법제도 및 지자체간 협의 등 다양한 문제가 연루되어 있어 단기적으로는 B2B 데이터 연동방식을 응용하여 구성하였다. 광역 중앙 제어를 위한 통합데이터베이스는 가상DB 방식을 고려하였으며, 이는 지자체별로 구성된 통합DB에 대한 인터페이스 및 Wrapper 플랫폼을 적용하였다. 이 플랫폼간의 연동은 WaterML2.0을 적용함으로써 단기간내 구현이 가능하도록 하고 상호운용성에 문제를 해결하며, 실시간 데이터 연계를 추구하였다. 본 연구를 통해서 궁극적으로는 수자원 및 물관리 데이터의 통합을 위해 해당플랫폼에서 스키마 맵핑, 프로토콜 변환 정합 등을 실시하며, 실시간 데이터 마이닝 및 통합이 가능하도록 구성함으로써 향후 스마트워터그리드의 빅데이터 플랫폼 개발까지 확장해나갈 수 있을 것으로 기대된다.

• Journal of Korean Library and Information Science Society
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• v.50 no.3
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• pp.23-47
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• 2019

In order to ascertain disciplinary differences in publication patterns that can help improve assessment of research performance in Korea, we analyzed the bibliometric data of six disciplines from Korea Citation Index. Results showed differences in research size, competitiveness, productivity, impact, and collaboration among disciplines. Disciplines in science were the largest in terms of author and institution followed by humanities and social science, but humanities produced the most publications per author, followed by social science and science disciplines. Sociology publications received most citation per paper but humanities received most citations per author, which was greatly influenced by the number of co-authors per paper. Distribution of author counts per paper varied widely across disciplines. Humanities were dominated by single-author publications, whereas the majority of publications in sciences were co-authored. The study also highlighted differences in citation lag time and illustrated differences in distribution and impact of core authors and institutions across disciplines.

• Journal of the Korean Society for Railway
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• v.19 no.4
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• pp.555-563
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• 2016

Line capacity of railways is a core criterion to decide maximum trips in accordance with traffic demand and a priority in railway investment to improve transportation capability. Particularly, because two operators will start revenue services in the HSR from mid-2016, the line capacity should be carefully calculated and controlled to avoid conflicts between the maximum number of KTXs, and the number needed to guarantee the effective competition of the operators. Meanwhile, there have been many arguments about calculating the line capacity, because this number is affected by the number of trips by train types, stopping pattern and dwell time in each station, journey time, crossing or passing, safety headway between trains, etc. To deal successfully with these kinds of problems, this study proposes a simulation method to calculate the line capacity that considers train operation according to the operator's service policies.

• Journal of the Korean Society for Railway
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• v.16 no.3
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• pp.233-239
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• 2013

This paper studied the stress of Metropolitan Transit driving crews. Stress to such workers can not only lead to fatalities and infrastructure damage but also enormous loss of competitiveness. The study was carried out to search for ways of alleviating stress of driving crews. In order to reduce the various factors that exacerbate job stress of driving crews of Metropolitan Transit, it is first necessary to expand training in order to enhance their expertise, and improve facilities to protect driving crews in the event of accidents. Second, psychological compensation or organization's systems may cause job stress. It may therefore be possible to solve fundamental problems through typical organization level approach such as leadership training programs. Third, job stress may be reduced through proper life habits such as personal regular exercise. Fourth, we need to improve driving crews' working conditions and adjust working hours by avoiding excessive performance competition and an unfair evaluation system, by understanding their mental states, and by setting up systems such as a comprehensive health improvement and management program at the organization level.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.21 no.5
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• pp.89-94
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• 2021

Recently, manufacturing companies are introducing many intelligent production processes that apply IIoT/ICT to improve competitiveness, and a system that maintains availability, improves productivity, and optimizes management costs is needed as a preventive measure using environmental data generated from air ejectors. Therefore, in this study, a dedicated control board was developed and LoRa communication module was applied to remotely control it to collect and manage information about compressors from cloud servers and to ensure that all operators and administrators utilize common data in real time. This dramatically reduced M/S steps, increased system operational availability, and reduced local server operational burden. It dramatically reduced maintenance latency by sharing system failure conditions and dramatically improved cost and space problems by providing real-time status detection through wired and mobile utilization by maintenance personnel.

• Knowledge Management Research
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• v.22 no.3
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• pp.201-215
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• 2021

Owing to COVID-19 pandemic and global recession, enterprises are facing more and more fierce competition. Under this situation, retaining as much as recruiting good employees has become a top priority for organization. However, post 90s, with very different characteristics from traditional workers, entered the labor market, and both employers and employees suffered from post-90's high turnover rate. Therefore, this study focuses on Chinese post-90s and examined the effects of work values they pursue (utilitarian orientation, interest congruence, long-term development, and innovativeness) on job satisfaction and turnover intention. In addition, the groups with less than or more than one year of service were compared and analyzed. A total of 267 Chinese workers born in the 90s participated in the survey. Our research findings show that utilitarian orientation affects both job satisfaction and turnover intention, but interest congruence only affects job satisfaction while innovation only affects turnover intention. And the moderating effect of tenure of service was partially verified. Various implications based on the result were discussed.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.28 no.6
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• pp.1415-1425
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• 2018

MMORPG genre is based on the belief that all users in virtual world are equal. All users are able to obtain the corresponding wealth or status as they strive under the same resource, time. However, game bot is the main factor for harming this fair competition, causing benign gamers to feel a relative deprivation and deviate from the game. Game bots mainly form GFG(Gold Farming Group), which collects the goods in the game indiscriminately and adversely affects the economic system of the game. A general game bot detection algorithm is useful for detecting each bot, but it only covers few portions of GFG, not the whole, so it needs a wider range of detecting method. In this paper, we propose a method of detecting GFG based on items used in MMORPG genre. Several items that are mainly traded in the game were selected and the flows of those items were represented by a network. We Identified the characteristics of exchanging items of GFG bots and can identify the GFG's item trade network with real datasets from one of the popular online games.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2014.10a
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• pp.811-814
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• 2014

There is increasing interest in the introduction of smart work as a flexible working form to perform a task without restrictions of time and place by using the information and communication technology as a creative innovative capacity has become an important element of enterprise competitiveness. However, because of the lack of understanding about smart work and concrete practices, most local SMEs are staying at the beginning of introducing the smart work. It is required to provide the standard of a smart work common structure and interface to quickly develop smart work services in a standardized way for SMEs and promote the deployment of the smart work in this environment. In this paper, we present standard development directions for the smart work service common structure and component interface to develop specialized services according to the size, the purpose and the needs of local SMEs.

• Journal of Practical Engineering Education
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• v.11 no.1
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• pp.25-31
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• 2019

The purpose of this study is to investigate the difference between motivation and learning strategies of students who have received academic probation and who have not while attending engineering college. The subjects of this study were engineering college students in Seoul and they participated in the learning strategy test at the teaching and learning center. The subjects of this study were 553 students, 22 of whom received academic probation and 531 didn't. In order to achieve the purpose of this study, we used MLST (Multi-dimensional Learning Strategy test) learning strategy checklists of Korea Guidance, which is a standardized test. A t-test was conducted to compare motivational and learning strategies between students with and without academic probation. As a result, the motivation score of the students with the academic probation was lower than that of those without the academic probation, and the score of the time management and note taking factors of the students with the academic probation were lower than those of the students without the academic probation.