• KOREAN JOURNAL OF CROP SCIENCE
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• v.25 no.1
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• pp.77-86
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• 1980

Asking to change the cropping patterns to save the labor and capitals in paddy rice cultivation, the study was intended to know the weed problems under the various possible cultural systems; namely, direct seeding (in broadcast and row), machine transplanting and hand transplanting. Under the conditions as weedy check plots, paddy yields were significantly variated among cropping systems, and the functions of panicle No. and spikelet No. to the yield were neglected, among others. However, the yield and yield components were narrowed among cropping systems, and the function of spikelets number per area was comparatively improved to the others.

• The Korean Journal of Archival Studies
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• no.78
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• pp.197-249
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• 2023

This paper focus on the demand for broadcast and video archive contents by users outside broadcasters as the archive openness and sharing projects of terrestrial broadcasters have become more active in recent years. In the process of creating works using broadcasters' released video footage, the study examined the criteria by which video footage is selected and the methods and processes utilized for editing. To this end, the study analyzed the the case of the 5.18 footage video sharing project 〈May Story(Owol-Iyagi)〉 contest organized by KBS in 2022, in which KBS released its footage about the May 18 Democratic Uprising and invited external users to create new content using them. Analyzing the works that were selected as the winners of the contest, the research conducts in-depth interviews with the creators of each work. As a result, the following points are identified. Among the submitted works, many works deal with the direct or indirect experience of the May 18 Democratic Uprising and focus on the impact of this historical event on individuals and our current society. The study also examined the ways in which broadcasters' footage is used in secondary works. We found ways to use video as a means to share historical events, or to present video as evidence or metaphor. It is found that the need for broadcasters to provide a wider range of public video materials such as the May 18 Democratic Uprising, describing more metadata including copyright information before releasing selected footage, ensuring high-definition and high-fidelity videos that can be used for editing, and strengthening streaming or downloading functions for user friendliness. Through this, the study explores the future direction of broadcasters' video data openness and sharing business, and confirms that broadcasters' archival projects can be an alternative to fulfill public responsibilities such as strengthening social integration between regions, generations, and classes through moving images.

• Journal of Intelligence and Information Systems
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• v.22 no.1
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• pp.107-118
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• 2016

The advent of 5G mobile communications, which is expected in 2020, will provide many services such as Internet of Things (IoT) and vehicle-to-infra/vehicle/nomadic (V2X) communication. There are many requirements to realizing these services: reduced latency, high data rate and reliability, and real-time service. In particular, a high level of reliability and delay sensitivity with an increased data rate are very important for M2M, IoT, and Factory 4.0. Around the world, 5G standardization organizations have considered these services and grouped them to finally derive the technical requirements and service scenarios. The first scenario is broadcast services that use a high data rate for multiple cases of sporting events or emergencies. The second scenario is as support for e-Health, car reliability, etc.; the third scenario is related to VR games with delay sensitivity and real-time techniques. Recently, these groups have been forming agreements on the requirements for such scenarios and the target level. Various techniques are being studied to satisfy such requirements and are being discussed in the context of software-defined networking (SDN) as the next-generation network architecture. SDN is being used to standardize ONF and basically refers to a structure that separates signals for the control plane from the packets for the data plane. One of the best examples for low latency and high reliability is an intelligent traffic system (ITS) using V2X. Because a car passes a small cell of the 5G network very rapidly, the messages to be delivered in the event of an emergency have to be transported in a very short time. This is a typical example requiring high delay sensitivity. 5G has to support a high reliability and delay sensitivity requirements for V2X in the field of traffic control. For these reasons, V2X is a major application of critical delay. V2X (vehicle-to-infra/vehicle/nomadic) represents all types of communication methods applicable to road and vehicles. It refers to a connected or networked vehicle. V2X can be divided into three kinds of communications. First is the communication between a vehicle and infrastructure (vehicle-to-infrastructure; V2I). Second is the communication between a vehicle and another vehicle (vehicle-to-vehicle; V2V). Third is the communication between a vehicle and mobile equipment (vehicle-to-nomadic devices; V2N). This will be added in the future in various fields. Because the SDN structure is under consideration as the next-generation network architecture, the SDN architecture is significant. However, the centralized architecture of SDN can be considered as an unfavorable structure for delay-sensitive services because a centralized architecture is needed to communicate with many nodes and provide processing power. Therefore, in the case of emergency V2X communications, delay-related control functions require a tree supporting structure. For such a scenario, the architecture of the network processing the vehicle information is a major variable affecting delay. Because it is difficult to meet the desired level of delay sensitivity with a typical fully centralized SDN structure, research on the optimal size of an SDN for processing information is needed. This study examined the SDN architecture considering the V2X emergency delay requirements of a 5G network in the worst-case scenario and performed a system-level simulation on the speed of the car, radius, and cell tier to derive a range of cells for information transfer in SDN network. In the simulation, because 5G provides a sufficiently high data rate, the information for neighboring vehicle support to the car was assumed to be without errors. Furthermore, the 5G small cell was assumed to have a cell radius of 50-100 m, and the maximum speed of the vehicle was considered to be 30-200 km/h in order to examine the network architecture to minimize the delay.

• Journal of the Korean Society of School Health
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• v.13 no.2
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• pp.295-317
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• 2000

This study was conducted to prevent oral disease of primary school, middle school, and high school students, providing basic data for the development of oral health education programs. Data were collected from 898 primary school, middle school, and high school students from March 2, 1999 to May 31, 1999. The results of this study are summarized as follows; 1) The subjects of this study were primary school students(32.6%), middle school students(33.0%), and high school students(34.4%). Boy students were slightly more prevalent than girl students. That is, primary school boys were 56.3%, middle school boys were 53.2%, and high school boys were 52.6%. 2) According to the self-judgement of oral health, primary school students were better than middle/high school students and boy students were better than girl students, 63.5% of primary school students and 57.8% of middle/high school students brushed their teeth once or twice a day. 3) 76.3% of middle/high school students and 63.5% of primary school students experienced dental caries. Girl students were higher than boy students in experiencing dental caries, 35.9% of primary school students and 27.6% of middle/high school students experienced periodontal disease. 4) 22.9% of primary school students and 7.9% of middle/high school students received oral examinations periodically. Girl students showed a higher rate than boy students in primary school, while boy students showed a higher rate than girl students in middle/high school. 5) Explaining to the reasons for reluctant visits to dental hospitals and clinics, 'no time to go' was highest(22.9% of primary school students; 27.4% of middle/high school students) and the rate of 'feeling scared' was second highest. Middle/high school students were more reluctant to visit dental hospitals and clinics than primary school students. In case of problematic symptoms in the mouth, the rate of 'feeling painful or cold in teeth when eating cold or hot foods' was highest, 71.3% of primary school students was concerned about oral health, while 68.6% of middle/high school students was concerned about it. 6) In gathering to the sources of information on oral health, the rate of medical institutions was highest(30.0%) in primary school students, while the rate of family members or persons around them was highest in middle/high school students. 7) 54.9% of primary school students received oral health education, while 13.1% of middle/high school students received it. Only 4.7% of middle school and high school girls received it. In relation to dental health education, the rate of 'possibility of prevention of oral caries or disease of the gum' was highest. 79.5% of primary school students and 80.3% of middle school students answered that they would attend oral health education. 8) 60.4% of primary school students and 60.2% of middle/high school students think the purpose of oral health is to prevent dental caries and disease of the gums. In preventing dental caries, 78.8% of primary school students and 71.8% of middle school students thought that periodical oral examination was effective, 88.4% of primary school students and 88.8% of middle/high school thought that brushing one's teeth was effective and 64.1% of primary school students and 50.7% of middle school students thought that the use of toothpaste containing fluoride was effective. In preventing periodontal disease, 91.1% of primary school students and 90.2% of middle/high school students thought that brushing one's teeth was effective, while 72.4% of primary school students and 70.3% of middle/high school students thought that teeth cleaning was effective. 9) 16.0% of middle school students and 12.7% of high school students thought that their oral health condition was healthy. According to individual experiences in dental treatment, the rate of experience of middle school students was higher than that of high school students, 12.7% of middle school students received oral examinations periodically, while only 3.3% of high school students did so. 10) In cases of 'having no problematic symptoms in the mouth' and 'concerns about oral health', the rate of middle school students was higher than that of high school students. In gathering obtaining information on oral health, the rate of obtaining it through broadcast media including TV, Radio, etc. was highest in middle school students, while the rate of obtaining it through family members or persons around them was highest in high school students. 11) 81.7% of middle school students have not received oral health education. In case of girl students, 97.3% have not received it in high school students. 85.6% of middle school students and 151.2% of high school students think that oral health education is necessary. 12) According to the knowledge level of oral health, the point of high school students($26.33{\pm}2.33$) was similar to the point of high school students($26.23{\pm}2.30$). It appeared that the point of primary school students was highest($26.35{\pm}2.50$) The more concerned about oral health the students were the higher the knowledge level of oral health was. In conclusion, the middle/high school students' knowledge level of oral health was lower than primary school students. The rate of middle/high School students' experience in oral health education was too low. Therefore, it is necessary to intensify oral health education for middle/high school students. Especially, the necessity of oral health education to girl students is strongly recommended. Developing an oral health education program for primary school, middle school, and high school students, related public authority and organizations, teachers; and dentists must actively make efforts together in order to maintain healthy teeth through having students prevent dental caries and periodontal disease.