• Bulletin of the Korean Space Science Society
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• 2011.04a
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• pp.24.4-24.4
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• 2011

Frozen orbit concept is very useful in designing particular mission orbits including the Sun-synchronous and minimum altitude variation orbits. In this work, variety of frozen and Sun-synchronous orbit conditions around the Moon is investigated and analyzed. The first two zonal harmonics of the Moon, J2 and J3, are considered to determine mean orbital elements to be a frozen orbit. To check the long-term behavior of a frozen orbit, formerly developed YonSei Precise Lunar Orbit Propagator (YSPLOP) is used. First, frozen orbit solutions without conditions to be the Sun-synchronous orbit is investigated. Various mean semi-major axes having between ranges from 1,788 km to 1,938 km with inclinations from 30 deg to 150 deg are considered. It is found that a polar orbit (90 deg of inclination) having 100 km of altitude requires the orbital eccentricity of about 0.01975 for a frozen orbit. Also, mean apolune and perilune altitudes for this case is about 136.301 km and 63.694 km, respectively. Second, frozen orbit solutions with additional condition to be the Sun-synchronous orbit is investigated. It is discovered that orbital inclinations are increased from 138.223 deg to 171.553 deg when mean altitude ranged from 50 km to 200 km. For the most usual mission altitude at the Moon (100 km), the Sun-synchronous orbit condition is satisfied with the eccentricity of 0.01124 and 145.235 deg of inclination. For this case, mean apolune and perilune altitudes are found to be about 120.677 km and 79.323 km, respectively. The results analyzed in this work could be useful to design a preliminary mapping orbit as well as to estimate basic on-board payloads' system requirements, for a future Korea's lunar orbiter mission. Other detailed perturbative effects should be considered in the further study, to analyze more accurate frozen orbit conditions at the Moon.

• Bulletin of the Korean Space Science Society
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• 2011.04a
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• pp.20.1-20.1
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• 2011

We present the results of far-ultraviolet (FUV) observations of comet C/2001 Q4 (NEAT) obtained with Far-ultraviolet Imaging Spectrograph (FIMS) on board the Korean microsatellite STSAT-1, which operated at an altitude of 700 km in a sun-synchronous orbit. FIMS is a dual-channel imaging spectrograph (S channel 900-1150 ${\AA}$, L channel 1350-1750 ${\AA}$, ${\lambda}/{\Box}{\lambda}$ ~ 550) with large image fields of view (S: $4^{\circ}.0{\times}4'.6$, L: $7^{\circ}.5{\times}4'.3$, angular resolution 5'-10') optimized for the observation of diffuse emission of astrophysical radiation. Comet C/2001 Q4 (NEAT) was observed with a scanning survey mode when it was located around the perihelion between 8 and 15 May 2004. Several important emission lines were detected including S I (1425, 1474 ${\AA}$), C I (1561, 1657 ${\AA}$) and several emission lines of CO $A1{\cap}-X1{\sum}+$ system in the L channel. We estimated QCO = ($2.58\;{\pm}\;0.64)\;{\times}\;1028$ s-1 from the production rate of CO 1510 ${\AA}$. We obtained L-channel image which have map size of $5^{\circ}{\times}5^{\circ}$. The image was constructed for the wavelength band of L-channel (1350-1750 ${\AA}$).We also obtained radial profile of S I, C I, CO with line fitting from central coma.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.11 no.1
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• pp.107-113
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• 2018

In this paper, we design and implement a contest application that enables artists to participate in contest activities, manpower, and job information using smart-phone, and to share and systematically manage the information. While the competition is very important for the artists, it is not easy for them to search the competition information due to lack of time. Therefore, it is effective to provide them with contest information suitable for their interests and to be more immersed in creative activities by sharing them. The core function is to provide a space where artists can share contests in real time through the contest bulletin board and aims to provide a variety of functions for convenient convenience, such as buying and selling of works by artists and spoon market for purchasing materials and art tools do.

• 대한공업교육학회지
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• v.32 no.1
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• pp.73-92
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• 2007

The purpose of this study was to develop ICT(Information and Communication Technology) teaching-learning materials for motorcycle safety education. Physical subjects which are relevant with motorcycle dynamics were introduced to increase the safety awareness through integrated learning such as the combination of technology and science. The results of this study were as follows : (1) Utilizing the physics basic theories which are relevant to motorcycle dynamics, the lesson plan of motorcycle ICT teaching-learning materials, which were included to plan and instruction action plan, was developed. (2) Flash animation or movie was developed to apply physics knowledge to technology in driving motorcycle. This is able to improve the attitude of driving motorcycle of students. (3) Through the contents of appendix of motorcycle safety driving section in this web-site developed here, junior and senior high school students would be able to strengthen their cognitive domain of motorcycle by themselves. (4) Using the web-site of this study, both teachers and students would be able to freely interact through an online bulletin board.

• Journal of Korean society of Dental Hygiene
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• v.9 no.1
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• pp.193-205
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• 2009

The purpose of this study was to examine the needs of learners in an advanced major course in a bid to strike a balance between theory and practice. And it's also meant to suggest an actual case of that effort in an advanced course. As a result of analyzing the collected data, the largest number of the learners who signed up for the advanced course chose that course to earn a bachelor's degree, and the second greatest group did that to bolster their expertise. The name of the college that offered that course (41.4%) had the most impact on their choice of it, followed by accessibility(28.6%). The most common thing they practiced in the oral health education course as one of major courses was forming a lesson plan, followed by teaching at schools and kindergartens, trial student teaching, producing PPT, making OHP materials, making a bulletin board and producing leaflets. During clinical activities for oral health education, the largest group considered it necessary to learn about more theories on educational psychology(54%), followed by the production of teaching media(29.9%) and teaching methods(25.3%). Likewise, the greatest group found it more necessary to practice educational psychology(42.5%), followed by the utilization of media(37.9%) and teaching methods(28.7%). An one-on-one interview was implemented before and after their classes to obtain more detailed information on their needs, and what their needs were in relation to the given curriculum was eventually confirmed, which made it possible to offer better education in response to their needs.

• Journal of the Korea Computer Industry Society
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• v.5 no.3
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• pp.383-392
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• 2004

Electronic BBS (bulletin board system) Ins been widely recognized as an appropriate medium for exchanging ideas and sharing information asynchronously. The communication ability if BBS is the main reason for utilizing it as a tool for collaborative learning. Researchers in the community reported a number if findings regarding the educational utilization if BBS recently. In this paper, we propose a qualitative method to measure communication activities using BBS so that the complex discussion behaviors of participants can be understood analytically. We propose characteristic vectors to describe discussion behaviors of groups and individuals, which can be conveniently used for characterizing and comparing discussion groups as well as individuals. The interactivity model representing interactive activities shows graphically the degree of inter activity if discussion groups as well as individuals. Also, time dependent measurements are investigated to analyze discussion activities with time. Experiments on the proposed measurements conducted on the Web-based discussion project using BBS demonstrate how measurements can be carried out, how characteristic vectors and inter activity model can be constructed and used.

• The Journal of the Korea Contents Association
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• v.16 no.2
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• pp.1-13
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• 2016

The purpose of this study is to explore the emotions of Facebook. Various types of emotions are being exchanged on Facebook. The emotional reactions make the Facebook different from previous electronic bulletin board. According to previous researches, computer-mediated communication can deliver visual symbols and non-verbal cues to enhance the abundance of meanings. Data were collected from 205 Facebook users and the number of users' posts were total 10308. The contents analysis was conducted to explore emotions of the 10308 Facebook posts. The results showed that the most frequent emotion was pleasure. The emotional distributions were different according to the contents types; text, video, photo, and link. For the text content type, emotion of curiosity was apparent and for the photo content type, emotion of love was more frequent than others, and for the video content type, emotion of surprise was salient. The results of the analysis for the shared contents also revealed that pleasure and hope were more frequent emotions than other emotions.

• Proceedings of the Korea Contents Association Conference
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• 2004.11a
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• pp.545-553
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• 2004

A researcher, who is a member of an academic society, is required to write a report on his or her research and present it at an academic workshop in order to have the contents of the research recognized by others. In order to do that, the researcher frequently has to look up the web pages of each workshop for information such as the submission deadline, paper information, announcements and news. On the other hand, the academic society mostly relies on e-mail or bulletin board to send information about itself to its members to inform its members about its latest news or developments. A system where the researcher can gain all the information required through just a single click and the academic society can provide its members with the necessary information through a simple step is required for the ease of both side. We will take a look at the domestic status of researches being done on such systems where the RSS standard has been applied and suggest a RSS-based dissemination model where the concept of personalization has been applied to satisfy the needs of the individual user.

• Bulletin of the Korean Space Science Society
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• 2008.10a
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• pp.31.2-31.2
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• 2008

We present the results offar ultraviolet (FUV, 1350-1750 ${\AA}$) auroral observations made by the Far-ultraviolet IMaging Spectrograph (FIMS) instrument on the Korean microsatellite STSAT-1. The instrument was capable of resolving spatial structures of a few kilometers with the spectral resolution of 2-3 ${\AA}$. The observations were carried out simultaneously with the measurement of precipitating electrons using an electrostatic analyzer (ESA, 100 eV-20 keV) and a solid state telescope (SST, 170 keV-360 keV) on board the same satellite. With a careful mapping of the field lines, we were able to correlate the particle spectrum to the corresponding FUV spectrum of the footprints of the FIMS image that varied significantly in fine scales. We divided the FIMS spectral band into the LBH long (LBHL, 1640-1715 ${\AA}$) and LBH short (LBHS, 1380-1455 ${\AA}$) bands, and compared the electron energies with the intensities of LBHL and LBHS for the well-defined inverted-V structures. The result shows a strong correlation between the total LBH intensity and the energy flux measured by ESAwhile the peak energy itself does not correlate well with the LBH intensity. On the other hand, it was observed that the ratio of the LBHL intensity to that of LBHS increased significantly as the peak electron energy increased, primarily due to a smaller absorption by O2 at LBHL than at LBHS.

• Proceedings of the Korea Contents Association Conference
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• 2003.05a
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• pp.237-244
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• 2003

With the rapid development of information and communication technologies(ICTs) and internet technology and the explosive increasing of internet users, we can find almost every municipal information of local governments by visiting the home page without visiting the city hall personally. And in the case of urban planning information they provide many kinds of information to inform the policy and results of urban planning to citizens The differences of urban planning information from other municipal information, at first many information of urban planning should be presented as spatial data, so we have to provide the geographic information with internet GIS, and second to realize bottom-up decision making process the exchanging of information between citizen and government should be adopted as bulletin board system(BBS) and an questionnaire in internet In this paper I evaluated the sites of urban planning information in the homepage of local governments by many index. the index are composed with 4 categories 20 items on information providing, 3 categories 12 items on communication, and 2 categories 8 items on internet GIS. And as a result I introduce some high scored sites at each category, and propose that we have to recognize the internet as the technological media to broaden the opportunities for the community people to participate in the policy-making in reference to their political demands.