• Journal of the Korea Institute of Information and Communication Engineering
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• v.7 no.8
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• pp.1638-1643
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• 2003

A shay has designing on the structure of new radio repeater for maritime safety communications system with economical and practical useful, that purpose be capable to exceedingly minimum the accident of small ship in sea, that is system. As Receive the urgency frequency from the SSB transceiver in a small fishery that transmit to convert VHF transceiver frequency. Otherwise, the VHF transmitter frequency is converting to the SSB receiver frequency. It has modeling of the hi­directional relay system, that is proposing the methode m the capability to mutual urgency communication between a SSB transceiver ship and VHF transceiver ship by new maritime safety communications system.

• Journal of Satellite, Information and Communications
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• v.9 no.1
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• pp.79-84
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• 2014

Increasing demand for realistic media and improvement of transmission and device techniques accelerate ultra-high definition(UHD) service realization. In Korea, the cable TV broadcasting companies are planning to commercialize in Apr. 2014. For the terrestrial TV broadcasting service, technical issues are considered for the specification of UHD broadcasting system. However, the frequency bands and the system bandwidth for the terrestrial UHD broadcasting system have not been decided. In this paper, we propose required spectrum bandwidth for the next-generation terrestrial broadcasting service considering source coding, error correcting codes and modulation techniques. Also, we propose frequency management plan for terrestrial UHD broadcasting system in which we divide all parts of the country into 9 frequency zones and allocate 4 frequency band to each frequency zone considering single frequency network (SFN).

• The Journal of the Convergence on Culture Technology
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• v.7 no.4
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• pp.421-428
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• 2021

This study intended to identify the differences of pre-service elementary school teachers' perceptions on instructional design between face-to-face and online instruction. Lesson plans for face-to-face and online instruction were analyzed by 84 participants who were seniors at C university of education. Results of content analysis indicate that 'Providing Learning Guidance' domain is the biggest domain in terms of the frequency gap between face-to-face and online instruction. Frequency differences by domains between face-to-face and online instruction were found to be significant as a result of Chi-square test. Frequency differences by instructional elements in the 'Providing Learning Guidance' domain between face-to-face and online instruction were found to be statistically significant as well. In conclusion, this study indicates the differences of pre-service elementary school teachers' perceptions on instructional design between face-to-face and online instruction, which implies the necessity for the development and implementation of professional development programs focusing on the perceptions on instructional design of online instruction for pre-service elementary school teachers.

• Journal of the Korean Society for Railway
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• v.20 no.4
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• pp.529-538
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• 2017

There has been much interest in optimizing the halting patterns of high-speed trains, for example by introducing more non-stop trains to supply faster train service to the passengers, which could later bring about a discussion about introducing new high speed train service with differentiated price and service. In general, halting patterns can be considered by constructing an efficient line plan, in which all demand should be covered and the total travel time can be reduced as much as possible. In this study, we present a two-step process based on two optimization models. One is to minimize total kilometers of trains to run on each route ; this will be done using a line planning model under the assumption of all-stop patterns. Then, in the next step, the all-stop patterns are optimally decomposed into several halting patterns in order to minimize the total travel time. We applied the two-step process to the latest demand data in order to develop KTX halting patterns as well as to determine the frequency of each line and compare the current line plan with the optimized one.

• Journal of the Korean Society of Hazard Mitigation
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• v.8 no.2
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• pp.75-82
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• 2008

Heavy rains and typhoons are the most critical meteorological disaster occurred in the Korean peninsular. Due to the global warming, the magnitude of heavy rains and typhoons is becoming heavier resulting in more damage annually. Therefore, it is required to establish a mitigation plan to reduce the damage from meteorological disasters. To do so, in general, it is better to establish a mitigation plan for each district considering the characteristics of a district than a single mitigation plan for the entire districts without considering the characteristics of an individual district. In this study, we provide fundamental data for establishing a mitigation plan from analysis considering the frequency and damage in monetary value by heavy rain and typhoon with the geological and social characteristics of districts. The annual damage reports published by the National Emergency Management Agency, dated from 1994 to 2003, are used for the analysis. The districts are classified into six categories by the geological and social characteristics. Also, the frequency and damage in monetary value are assessed for each district. Based on them, the damage degree by heavy rain and typhoon from 1st to 4th is assigned to each district. The assigned damage degree is, then, analyzed with geological and social characteristics of each district to show the status of damage by meteorological disasters on the district.

• Journal of Advanced Navigation Technology
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• v.2 no.2
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• pp.143-156
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• 1998

Incheon International Airport(IIA) is planned to open in about two years. Korean government has an ambition to make IIA a major hub airport in Northeast Asia. The most essential and required condition for an airport to be a successful hub airport in a certain region is to have more efficient flight service network than the other airports in the same region. IIA should compete with Japanese airports to be a major hub in Northeast Asia because Japanese government also has a plan to expand greatly the airport capacity in Tokyo area and Kansai airport in Osaka. It is necessary for both IIA and Korean national air carriers to compose efficient flight service network considering hub competition with Japanese major airports. As the liberalization of international air transport industry would give more marketing freedom to airlines, they would plan the flight service network and flight schedule based on market analysis instead of governmental regulations. In the economically liberalized environment, it is very required to analyze air passengers' flight choice behaviour in order to induce other carriers and passengers through IIA's attractive flight service network. Disaggregate model is more appropriate than aggregate model to analyze consumers' behaviour. The information derived from disaggregate choice model of air passengers could be utilized in devising efficient flight network and schedule plan. Value of travel time or trade off ratio between flight frequency and travel time which could be estimated from discrete choice model could be utilized for scheduling an efficient flight plan for airlines and composing efficient flight service network for IIA.

• Proceedings of KOSOMES biannual meeting
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• 2007.11a
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• pp.211-214
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• 2007

In this paper, we have designed microstrip antenna if 800[MHz] band It will be able to integrate TRS(Trunked Radio System), GSM(Global System for Mobile telecommunication) band including the CDMA(Code Division Multiple Access) band we designed repeater and a base station antenna which is possible at the ship and marine of safety. It is improves a narrow bandwidth problem of microstrip antenna. It had U-shaped feeding structure at a rectangular patch And ground or feeding structure used between dielectric constant(${\varepsilon}_T$ = 2.1), patch or feeding structure used between dielectric constant(${\varepsilon}_T$ =1). So it used a duplex resonance effect Designed frequency bandwith(V5WR 2:1) if the antenna showed good characteristic of $780[MHz]{\sim}1.83[GHz]$ to 2.61[GHz]. Also the E-plan and H-plan all profit 9.4[dBi] above, the 3[dB] beam width showed the characteristic over the E-plan and H-plan $60^{\circ}$ to be improved.

• Journal of Korean Society of Rural Planning
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• v.17 no.1
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• pp.13-27
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• 2011

This study analyzed the budget investment plans for the unit-project items(UPI) of 176 project districts for the rural village comprehensive development projects (RVCDP). This study classified the master plan reports of 176 project districts into 88 unit project items in aspect of project management, in order to analyze characteristics of distribution of budget in each project item. Most of all unit project items have similar types of uniform distribution with plus skewness in frequency pattern analysis except the total budget of the project district. This study analyzed the characteristics of budget distribution per province, year, and geographical types of region. Furthermore this paper also analyzed ratio of budget in unit project items to find out distribution pattern of each budget between project items over time. The hierarchical system for UPI of RVCDP consisted of three steps, which are 4 items of the first step on Strength of Rural-urban Exchange & Regional Capability (RURC), Green-income Infrastructure & Facility (GIF), Culture- health-welfare Facility, and Eco-environment & Landscape facility (ELF), 13 items for the second one, and 52 items for the third project items. From the results of the budget investment analysis for 5 years from 2004 to 2008, the budget investment ratios of RURC and ELF have steady state for every year, while GIF in decreasing and ELF in increasing over time. The ratios of UPI on infrastructure were decreased, whereas those on culture, health, and welfare were increased. Portion of tow project items among 52 items, which are community centers for village residents and rural experimental study facility, has 30% of total budget investment. Futhermore, the budget ratios of seven project items showed 50% of total budget. Average value of project budgets for five years was optimized as a type of exponential function in the case of decent array for ranking order.

• Journal of the Korean Society of Marine Environment & Safety
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• v.13 no.3
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• pp.219-222
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• 2007

In this paper, we have designed microstrip antenna of 800[MHz] band. It will be able to integrate TRS(Trunked Radio System), GSM(Global System for Mobile telecommunication) band including the CDMA(Code Division Multiple Access) band. we designed repeater and a base station antenna which is possible at the ship and marine of safety. It is improves a narrow bandwidth problem of microstrip antenna. It had L-shaped feeding structure at a rectangular patch and added the parallel L-slot that used a duplex resonance effect. Also for the improvement of profit the stack with the perpendicular. Designed frequency bandwith(VSWR 2:1) of the antenna showed good characteristic of 789${\sim}$1046[MHz] to 292[MHz](36%). Also the E-plan and H-plan all profit 6.4[dBi] above, the 3[dB] beam width showed the characteristic over the E-plan $44.7^{\circ} and H-plan $61.8^{\circ} to be improved.

• Journal of Korean society of Dental Hygiene
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• v.11 no.3
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• pp.363-372
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• 2011

Objectives : The purpose of this study was to pursue an efficient operating plan by surveying the cognition and demand level for major deepening course. Methods : Questionnaire survey was carried out targeting 135 dental hygienists who work in Cheonan and neighboring region. The collected data was performed frequency & percentage, T-test and ANOVA analysis. Results : 1. As for dental hygienists' acquiring academic degree, 77.0% of them responded to have interest. As for a desired route of acquiring academic degree, the major deepening course or Credit Bank System was the highest with 62.2%. 2. As a result of surveying cognition on major deepening course, 73.3% responded to know. A route of having come to know was the largest in senior or friend with 34.8%. Necessity of major deepening course was responded to be necessary with 89.7%. 89.1% of them clarified to have intention of acquiring. 3. The curricular subject, which is desired to be learnt for a plan of operating major deepening course, was the highest in the major field with 63.0%. 4. As a result of comparing an interest, necessity, and intention of acquisition on major deepening course depending on general characteristics, the statistically significant difference wasn't shown. Conclusions : These results suggest that major deepening of course through active public should be aware that many dental hygienists will be subject to a variety of programs and development of clinical course and a practical hands-on education is expected to be strengthened.