• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.20 no.2
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• pp.171-178
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• 2020

Many countries are establishing and operating blended learning that combines the advantages of online and offline education. However, online education lecture-based Mooc courses have a very low level, with a graduation rate of less than 5-10%. Therefore, in order to increase the graduation rate of students taking online Mooc distance education lectures that anyone can easily take lectures anytime, anywhere on the web-based basis, it is necessary to introduce automatic analysis of students' understanding level of lectures and an automatic academic warning system. Moreover, in order to enter an advanced education country, it is necessary to develop an automatic judgment SW for wrong answer rate, automatic summary SW for lectures, and automatic analysis SW education for lecture-based weak subjects based on mixed learning levels. In order to improve this problem, in this paper, we proposed and simulated an automatic summarization system for lecture contents, an automatic warning system for incorrect answers, and an automatic judgment algorithm for weak subjects.

• Proceedings of the Korean Society of Computer Information Conference
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• 2011.01a
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• pp.149-153
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• 2011

이 연구는 전자교육에서 성인여성 학습자를 중도탈락에 이르게 하는 요인을 도출하고, 이 중에서 가장 큰 영향을 주는 요인을 찾음으로써, 궁극적으로는 수료율을 제고하는데 목적이 있다. 이를 위해, 선행연구 분석을 통해 도출된 9가지 요인 중 어떤 요인이 중도탈락에 영향을 미치고, 그 영향력은 얼마인지 알아보기 위해 16개의 설문문항을 구성하여 K 기관의 교육생을 대상으로 설문을 실시하였다. 연구결과, 전자교육에서 성인여성 학습자의 중도탈락에 영향을 주는 요인은 결혼 여부, 내적 동기, 교육기관의 지원, 가사와 육아, 학습가능 시간 등 5가지로, 내적 동기, 학습가능 시간, 결혼 여부, 교육기관의 지원, 가사와 육아 순으로 중도탈락에 대한 영향을 미쳤다. 즉, 학습진행 시 내적 동기의 만족도가 높을수록, 학습 시간의 부담이 적을수록, 미혼이며, 교육기관의 지원에 만족도가 높을수록, 또 가사와 육아에 부담이 적을수록 수료를 할 가능성이 더 큰 것으로 나타났다. 연구결과를 토대로 전자교육에서 성인여성 학습자의 수료율을 제고하기 위해서는 성인여성을 대상으로 한 전자교육 과정 운영 시 결혼 여부, 내적 동기, 교육기관의 지원, 가사와 육아, 학습가능 시간의 요인을 고려해야하며, 그 중 결혼 여부, 가사와 육아부담 등의 여성학습자의 일반적인 특성에 따른 중도탈락을 줄이기 위해서는 교육기관의 역할이 중요하다. 또한, 성인여성 학습자의 중도탈락에 가장 큰 영향을 미치는 내적 동기 향상을 위해 과정설계 시 여성학습자 위주의 맞춤형 교수설계전략을 세우는 것이 중요하다. 성인여성 대상 전자교육에서의 학습자 중도탈락 요인들의 인과관계 및 그에 따른 영향력을 분석하는 연구를 통해 도출된 결과를 바탕으로 성인여성 학습자의 중도탈락을 줄일 수 있는 실증적인 방법론에 대한 연구를 통해 중도탈락률을 줄이는 것은 물론, 학업성취도 및 만족도를 높이고 나아가서는 여성의 사회진출을 도울 수 있는 연구가 필요하다.

• Journal of the Korean Society for Library and Information Science
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• v.35 no.4
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• pp.97-122
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• 2001

This empirical study investigated the effect of choice of record field(s) upon which to search on retrieval performance for a large operational bibliographic database. The query terms used in the study were identified algorithmically from each target set in four different ways: (1) controlled terms derived from index term frequency weights, (2) uncontrolled terms derived from index term frequency weights. (3) controlled terms derived from inverse document frequency weights, and (4) uncontrolled terms based on universe document frequency weights. Su potable choices of record field were recognised. Using INSPEC terminology, these were the fields: (1) Abstract. (2) 'Anywhere'(i.e., ail fields). (3) Descriptors. (4) Identifiers, (5) 'Subject'(i.e., 'Descriptors' plus Identifiers'). and (6) Title. The study was undertaken in an operational web-based IR environment using the INSPEC bibliographic database. The retrieval performances were evaluated using D measure (bivariate in Recall and Precision). The main findings were that: (1) there exist significant differences in search performance arising from choice of field, using 'mean performance measure' as the criterion statistic; (2) the rankings of field-choices for each of these performance measures is sensitive to the choice of query : and (3) the optimal choice of field for the D-measure is Title.

• The Bulletin of The Korean Astronomical Society
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• v.43 no.1
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• pp.39.4-40
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• 2018

KMTNet 광시야 망원경의 성능 개선을 위해 2017년에 이루어진 주요 작업으로 주경 배플(baffle) 설치, 주경 코팅, 돔 플랫(dome flat) 장치 설치에 대해 발표한다. 망원경 주경의 가장자리(turn down edge)는 경면 가공이나 코팅 상태가 균질하지 않을 수 있으며, 이로 인한 난반사는 밝은 별 주위에 넓은 wing profile과 여러 갈래의 방사상 빛줄기를 만든다. 이런 난반사를 제거하기 위해 주경면 바로 앞에 배플을 설치하였다. 주경의 광학 성능과 집광력이 최적이 되도록 배플 내부 직경 값을 1,580 mm로 조정하여 설치한 결과, 관측 영상에서 별의 영상이 크게 개선되었다. 호주 관측소는 상대적으로 습기가 높아서 망원경 주경의 반사율이 빨리 낮아졌으며, 이를 개선하기 위해 기존의 코팅(protected silver)을 제거하고 알루미늄으로 새로 코팅하였다. KMTNet 3개 관측소는 주경의 반사율과 코팅 면의 확대 영상을 정기적으로 모니터링하여 광학 성능의 변화를 추적하고 있다. 밤하늘 플랫(twilight sky flat) 영상을 보완하기 위해, 돔 인클로져에 플랫 스크린과 광원을 설치하여 돔 플랫 영상을 획득하였다. 마지막으로 KMNet 관측시스템을 운영하며 발생한 돔 회전 및 돔 셔터 구동부 문제 등에 대해 소개하고, 문제 발생 원인과 주기, 문제 해결 방안을 발표한다.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.7 no.2
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• pp.13-25
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• 2008

In this paper, we propose the Location Awareness System adjusting Ranging Technology for CSS(Chirp Spread Spectrum) which is adopted on 2.45GHz standard in IEEE 802.15.4a and TOA(Time-of-Arrival) algorithm. The conventional methods have adopted RSSI, ultrasonic waves and infrared rays in Zigbee. RSSI measures strength indication of received signal and recognizes the position of nodes in RF boundary. However, this technology has the following problems; lots of error by the change of the channel environment and much power consumption. In this paper, adopting chirp pulse on 2.45GHz standard in IEEE 802.15.4a and SDS-TWR(Symmetrical Double Side-Two Way Ranging) method using the characteristic of Spread Spectrum, a new Location Awareness System is suggested. The distance and the coordinate are measured within ${\pm}\;5cm$ by TOA(Time of Arrival) algorithm and proposed algorithm and the data in error rate is decreased less than 1%. Through these results, the algorithm suggested in this paper is verified for its performance in a computer simulation.

• Journal of Korea Multimedia Society
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• v.1 no.1
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• pp.37-44
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• 1998

While the SGML(standard generalized markup language) tend to be used in multimedia document management systems, still binary document images are widely used in servicing the information of printed documents at digital libraries. But the printed documents are scanned in 200 dpi resolution and the scanned binary document images are compressed by the ITU-T T.6 method, so they have difficulties in representing them in good quality and compressing them very efficiently. In this paper, by considering quality of the binary document images and expandability and effectiveness of database of them, we show that the suitable scanning resolution of them is 600 dpi and the best compression method is the JBIG. A staged service strategy of them is also suggested to solve the difficulty caused from long decompression time of the JBIG by analyzing characteristics of retrieving the binary document images in monitor and printer. In experiments for several typical binary document images, high compression rate of the JBIG and effectiveness of the staged service strategy are verified.

• Journal of Navigation and Port Research
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• v.26 no.4
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• pp.383-390
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• 2002

The time cost of ship end cargoes is one of the most important data for decision-making of port investment and operational efficiency. Studies in this area were initiated internationally by Goss and Mann in late 70's and also done in Korea 10 years ago using the same methodology as Goss. The main purpose of this paper is to revisit to estimate the time cost using updated data. The estimation was undertaken sampling data on various investment and operating costs by vessel from 205 vessels, comprising 47.5％ of the notional fleet in Korea as well as on cargoes from international trade statistics. Compared with the study of 10 years ago, major finding of this research is that time costs of liquid and dry bulk carriers have increased, in case of the former type, showing almost doubled cost increase. The increase is deemed to be caused by very expensive LNG carriers. Lowered social discount rate in this study compared with 10 years ago, in general, has mused the costs to stay at similar level to the previous study. Sensitivity tests were conducted using various social discount rates.

• Journal of the Korea Organic Resources Recycling Association
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• v.13 no.4
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• pp.107-117
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• 2005

The objective of this study was to investigate the proper operation conditions of fenton oxidation such as initial pH, $H_2O_2/Fe^{2+}$ ratio, $H_2O_2/Fe^{2+}$ dosage amount, and neutralizing agent for pretreatment of the livestock wastewater. Fenton oxidation reagents were reacted with the livestock wastewater for 2 hours at 120 rpm and the settling was performed for 2 hours using jar-tester apparatus under the different experimental conditions. And then the supernatant was sampled and measured for the residual $H_2O_2$, $COD_{Cr}$, and SS. The results are as follows; optimum initial pH=4, optimum $H_2O_2/Fe^{2+}$ ratio=10:1, optimum $H_2O_2/Fe^{2+}$ dosage amount=5,000/500 mg/L and $Ca(OH)_2$ as proper neutralizing agent. The removal efficiency of $COD_{Cr}$ and SS were 43% and 84% under those optimal fenton oxidation conditions.

• Journal of the Korea Society of Computer and Information
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• v.13 no.6
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• pp.25-31
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• 2008

The web has been evolving as an indispensable part of our lives since Berners Lee introduced the first web sever and browser in 1990. From the web end user's point of view, the response time is a matter of concern. Moreover the throughput is an important factor to consider for the system manager's point as well. It's not easy to estimate the performance of a web application because it depends on various elements comprising the whole operational environment of the Internet from networking, client and server computing powers, DBMS and OS capabilities, to application itself. This paper suggests a coarse grained simulation model for web application performance estimation based on the data measured by Buch and Pentkowski [1] and the analytical model proposed by Gunther [2]. The result of the simulation model almost coincides with the measured data and estimates the performance of a new environment.

• Journal of the Korean BIBLIA Society for library and Information Science
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• v.26 no.2
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• pp.269-287
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• 2015

The purpose of this study is discussing the applicability of a logic model as a mean measuring library outcomes. For a case study, this paper suggested a full framework for Reading Academy, a reading program for children and adolescents. Among the outcomes composing of the framework, medium-term outcomes were analyzed by manipulating the data the library have in its database. The findings say what the output evaluation could not show. In terms of book circulation, this program positively influenced to 52 percent of participants. Additionally, some participants joined reading book clubs after the program and some were likely to read books in various topics. This program, however, didn't make a positive impact on its re-attendance and other cultural programs' attendance. These findings indicate that the logic model contributes in the field of library outcomes and values.