• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.15 no.12 s.91
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• pp.1152-1160
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• 2004

OFDM technique was adopted as the standard of IEEE 802.1 la and it has been widely used for wireless LAN, European DVB/DAB system, Korean DMB system. In the standard of IEEE 802.11a the data packet is composed of two parts, preamble and data. Preamble is composed of short pilots and long pilots, which are used for synchronization and estimation of frequency offset and channel. We can also compensate phase noise effect in the transceiver by using above pilots. The phase noise is more complicate than frequency offset and seriously affects system performance. In this paper, we newly propose CPE and ICI simultaneous compensation method to compensate phase noise generated by transceiver oscillator and compare with previous studies. As results, phase noise effect can be significantly compensated by CPE cancellation method, PNS algorithm and our proposed CPE and ICI compensation method. Especially, the proposed CPE and ICI compensation method can achieve the best BER performance compared with original OFDM, CPE cancellation method and PNS algorithm.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.18 no.10
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• pp.1107-1116
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• 2007

In this paper, a broadband open stubs band pass filters which can suppress the second harmonics using Z-transform technique, is designed, fabricated and characterized. The proposed broadband filters integrate the band stop filter with the FSCS structure and ${\lambda}_g/4$ open stub in order to suppress the second harmonics. Due to insertion of BSF at input and output terminal, the size of the filter was increased in the conventional filter, however, in the proposed structure, the position of inverter that connects the stubs can be integrated between those stubs, thereby decreasing the size. So, it can be fabricated in the size of $18.7{\times}16.9mm^2$ which is smaller size than conventional one. The measured results of the proposed filters have center frequency of a 5.8 GHz with bandwidth of 95 %, insertion loss of 0.6 dB, return loss of 14 dB. The simulation results are consistent with measurement results. The filter is designed far X-band satellite communication and ITS applications.

• Journal of the Korean Society for Library and Information Science
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• v.44 no.4
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• pp.249-276
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• 2010

With the rapid growth and development of information technology and the Internet, the amount of information published in electronic formats such as video, audio, digitalized text, etc. and the number of users accessing information online to satisfy their information needs are growing at a tremendous rate. This study analyzes standardized components to construct ERMS and proposes a model of ERMS based on the result of the analysis. The main functions of ERMS in university libraries are: 1) ERMS can manage and control access information to various electronic resources, metadata, holdings, user resources. Also, ERMS can be compatible with an existing library system such as IR(Information Retrieval) system, linking system, or proxy system. 2) ERMS should completely be compatible with acquisition and cataloging systems for effective management and control of integrated information organization and library budget. 3) ERMS should systematically and effectively manage license information on electronic resources. 4) ERMS should provide ideal and effective environment for use and access control of electronic resources in a library and integrated tool to manage and control all of electronic resources. Additionally, this study points out the need to organize committee groups to establish standardized rules and collaborative management of electronic resources among university libraries like DLF ERMI and redesign organizations in a library and a librarian's job description.

• Journal of the Korea Society of Computer and Information
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• v.25 no.11
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• pp.229-238
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• 2020

Upcoming 4th industrial revolution era and the post-covid19 made procedure, contents, and the ways of education innovative changes. Thesis analyzed the changes of educational procedures of universities unsing Bigkinds of 'KPF', (which is Korea Press Foundation) and DataLab system of 'Naver'. The following three results were derived from relational analysis, monthly keyword trend, and related word analysis with 633 cases searched for the keyword of "university curriculum innovation, creativity, and convergence." Firstly, the frequency of relationship keyword analysis of recent 4 years(2016~2020) was ministry of education(190), industrial revolution(154), system(137), career(136), global(131), smart(97), and enrolled students(95) in order. Secondly, The frequency of keywords related to the related words was Human Resources Development (136), Industrial-Academic Cooperation (119), Education Ministry (86), Specialization (69), and LiNC (62), which showed the importance of supporting the government (Ministry of Education) and fostering human resources, industry-academic cooperation, LiNC, and characterization in order to foster human resources in universities. According to this study, the paradigm of education is the artificial intelligence environment of the fourth industrial revolution, which is meaningful in presenting the direction of specialization, industry-academic cooperation, smart, and globalization, and the future direction of education that fosters creative talent in the era of the fourth industrial revolution.

• The Journal of the Korea Contents Association
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• v.10 no.5
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• pp.115-123
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• 2010

Because of development of information technology, moving picture can run various platforms. We should consider and apply users' attitude as well as production technique because convergence between mobile and media technology may be increased full-browsing service using mobile device. Previous research related to production technique in various platforms only focus on video quality and adjustment of screen size. However, besides of technical side, production techniques should be changed such as image production as well as image editing by point of view aesthetic. Mise-en-scene such as camera angle, composition, and lighting is changed due to HD image. Also image production should be changed to a suitable full-browsing service using mobile device. Therefore, we would explore a new suitable production techniques and image editing for smart phone. To propose production techniques for smart phone, we used E-learning production system, which are transition, editing technique for suitable converting system. Such as new attempts are leading to new paradigm and establishing their position by applying characteries such as openness, timeliness to mobile. Also it can be extended individual area and established as expression and play tool.

• The KIPS Transactions:PartD
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• v.9D no.6
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• pp.1017-1024
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• 2002

According as mobile computing environment is generalized by development of wireless networking technology and communication device, mobile host uses local cache for extensibility and early response time. and reduction of limited bandwidth. This time, between mobile host and mobile support station cache need consistency interested person of done data accordingly much techniqueses propose. Existent consistency techniques because detection based techniqueses are used mainly and broadcast periodic invalid message considering frequent disconnection. However, these techniqueses increase abort step through increase or delay of transmission message number by accuracy examination of data. Therefore, because mobile host deletes cached data, and extensity are decreased. Techniques that is proposed in this paper did to perform refering update frequency about object that page request or when complete update operation happens to solve these problem. Therefore, have advantage that response is fast because could run write intention declaration or update by update frequency electively asynchronously when update operation consists and abort step decreases. Also, improved extensity running delete or propagation electively according to update frequency about periodic invalid message gone since disconnection.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.44 no.3
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• pp.218-227
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• 2016

Korean government plans to launch a lunar orbiter and a lander to the Moon by 2020. Before launch these two proves, an experimental lunar orbiter will be launched by 2018 to obtain key space technologies for the lunar exploration. Several payloads equipped in experimental lunar orbiter will monitor the surface of the Moon and will gather science data. Lunar orbiter sends telemetry and receives tele-command from ground using S-band while science data is sent to ground stations using X-band when the visibility is available. Korean deep space network will be mainly used for S and X-band communication with lunar orbiter. Deep Space Network or Universal Space Network can also be used for the S-band during trans-lunar phase when korean deep space network is not available and will be used for the S-band in normal mission orbit as a backup. This paper analyzes a visibility condition based on the combination of various ground antennas and its mask angles according to mission scenario to predict the number of contacts per day and to build an operational scenario for the lunar orbiter.

• Journal of Korean Society of Transportation
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• v.27 no.6
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• pp.29-44
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• 2009

A variety of research efforts, using advanced wireless communication technologies, have been made to develop more reliable traffic information system. This study presents a novel decentralized traffic information system based on vehicle infrastructure integration (VII). A major objective of this study was also to devise a methodology for determining appropriate spacing of roadside equipment (RSE) to fully exploit the benefits of the proposed VII-based traffic information system. Evaluation of travel time estimation accuracy was conducted with various RSE spacings and the market penetration rates of equipped vehicle. A microscopic traffic simulator, VISSIM, was used to obtain individual vehicle travel information for the evaluation. In addition, the ANOVA tests were conducted to draw statistically significant results of simulation analyses in determining the RSE spacing. It is expected that the proposed methodology will be a valuable precursor to implementing capability-enhanced next generation traffic information systems under the forthcoming ubiquitous transportation environment.

• Journal of The Korean Association For Science Education
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• v.35 no.5
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• pp.885-893
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• 2015

In this study, we compared the use of information and communications technology (ICT) by middle school teachers in Korea and other countries utilizing the teacher survey data of the IEA International Computer and Information Literacy Study (ICILS) 2013. The ICILS target population consisted of all students in the eighth grade. We compared Korea with Australia, the Czech Republic, Norway, and Poland, which are nations showing the highest achievements in computer and information literacy. We selected nine questions from the teacher questionnaire and divided them into the categories of computer use, use of ICT for teaching and learning, and the ICT support environment in school. In comparison to their counterparts in other countries, Korean middle school science teachers used computers frequently and also had high ICT self-efficacy. They were confident in their ability to use computers for general tasks, but not in their ability to use computers for teaching and learning. The Korean teachers also had a high percentage of utilization of presentation and graphics software. Also, the proportion of activities concerning the information provided and teacher-led tasks was high, but the proportion of activities for student collaboration or peer interaction was low. In Korea, middle school science teachers had more negative than positive views of using ICT in teaching and learning. The teachers thought that computer-related resource support and digital learning materials were insufficient and that the computer model was outdated in schools. Therefore, we propose to build an ICT infrastructure and to develop and disseminate ICT teaching and learning methods for student activities.

• Journal of Digital Convergence
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• v.10 no.11
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• pp.691-699
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• 2012

"Information", which is circulated in society by information technology development represented by computer, has brought innovation not only to physical civilization, but also deep into our daily lives. This is to say that information has brought fundamental change to its form of existence, and value system through being faster regarding the circulation and the way of management being diverse. As time goes by, this kind of change would stimulate more changes to be made as the development of scientific civilization. Therefore, informatization is one of the important characteristic that defines modern society's essence, but on the other side, information has been taken advantage of that temperament and abused in a lot of different ways. "The Law Regarding Computer Network Diffusion Expansion and Usage Promotion"(1986), as a counterplan of informatization is our nation's first Act about informatization, which enacts national policy and system about this issue. Since then, many laws has been enacted down to "Private Information Protection Act"(2011), forming a comprehensive system. The basic background of these laws are based upon the premise that even if the place where the information is managed is virtual space, rules that are considered valid in the real world should be basically applied in the virtual space. Therefore, the violation of the law in the real world is also considered the violation in the virtual space. This direction of current law regarding information is shared with both the theories and the reality. However, current law system and notion are based upon the premise that the law regards material objects, thus the characteristic of the information, which is "Immaterial Being" is not reflected. Also, the management and approach to this issue is allopathic, exposing many problems. Thus, this paper examines the way of protecting information stipulated in the current law, contemplates its protection scope and limitation, and seeks the direction of the improvement, based on the critical mind explained above.