• Journal of Digital Convergence
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• v.12 no.12
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• pp.37-47
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• 2014

The characteristics of the spectrum, which are necessary for mobile telecommunication services, may determine the advantage of operators' competition for mobile services. We have a focus on the possibility that there would be the core spectrum within the frequencies. We define the core spectrum of frequencies in terms of 4 criteria (global source/roaming, cost-effectiveness, the experience of utilization and the possibility of use). They are based on the aspects of applicative and economic effectiveness by not technological and but market conditions. We have explored the current core spectrum by using the stepwise selection from these criteria. Our result indicates that the core spectrum may be movable with the development of technology and the flow of time. The results of this paper could be practically used as the reasonable justifications of the policies for not only the competition management but also the alignment about the frequencies for mobile telecommunication.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.49 no.5
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• pp.1-6
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• 2012

Recent trend of pursuing smart life began to affect the usage of vehicle in real life. The next generation of the smart vehicle services start to utilize telecommunication technology and sensing techniques for the advanced safety and efficient use of road for drivers, while there's still decency in satisfaction about vehicular safety upgrade. For this purpose, a new technology is devised as Wireless Access in Vehicular Environment(WAVE). Foreign industries now are developing technologies of key components, platform and services related to WAVE. Domestic industry just starts to develop the related technologies about WAVE, although the frequency for WAVE is not allocated. This paper introduces the status of technical standards for WAVE and the status of developing components of WAVE. And this paper also proposes the guidance of frequency allocating policy for WAVE through frequency interference experiments.

• Journal of Digital Convergence
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• v.12 no.11
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• pp.309-316
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• 2014

In this paper, we propose an efficient detph map creation method using Graph Cut and Discrete Wavelet Transform. First, we have segmented the original image by using Graph Cut to process with its each areas. After that, the information which describes segmented areas of original image have been created by proposed labeling method for segmented areas. And then, we have created four subbands which contain the original image's frequency information. Finally, the depth map have been created by frequency map which made with HH, HL subbands and depth information calculation along the each segmented areas. The proposed method can perform efficient depth map creation process because of dynamic allocation using depth information. We also have tested the proposed method using PSNR(Peak Signal to Noise Ratio) method to evaluate ours.

• Journal of Korean Library and Information Science Society
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• v.50 no.4
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• pp.339-358
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• 2019

The purpose of this study is to understand the topics of the research for the establishment of cooperative platform between libraries, archives, and museums that carry out the common task of providing knowledge information in a broad sense. To achieve the purpose of this study, 637 bibliographic information on three institutions were collected from the Web version of Scopus database. Among the collected bibliographic information, 5,218 words were extracted through NetMiner V.4 and analysed topic modeling. The results are as follows: First, as a result of analyzing the frequency of word appearance according to the tf-idf weight 'Preservation' was the most hottest topic. Second, the topic modeling analysis through LDA(Latent Dirichlet Allocation) algorithm resulted in 13 topic areas. Third, as a result of expressing 13 topic areas as a network, repository construction was the central topic, and the research topics such as cooperation among institutions, conservation environment for collections, system and policy discovery, life cycle of collections, exhibition of information resources, and information retrieval were closely related to the central topic. Fourth, the trend of 13 topic areas by year 1998 is limited to the specific subjects such as system and policy discovery, information retrieval, and life cycle of collections, while the subsequent studies have been carried out after that year.

• Journal of Energy Engineering
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• v.29 no.2
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• pp.23-29
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• 2020

In this study, the last 10 years of news data on fine dust was collected and 80 topics are selected through LDA analysis. As a result, weather-related information made up the main words for the topic, and we can see that fine dust becomes a big issue below 10 degrees Celsius. The frequency of exposure to the media and the maximum concentration of fine dust are correlated with positive. Topics related to fine dust reduction measures and the government's comprehensive measures over the past decade, topics related to products such as air purifiers related to fine dust, topics related to policies protecting vulnerable people from fine dust, and topics on fine dust reduction through R&D were found to be major topics. Measures against fine dust as a social issue can be seen to be closely related to the government's policy.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.29 no.3
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• pp.200-213
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• 2018

Herein, we survey the current state of the recent legal revision of the Citizens Broadband Radio Service, a type of city spectrum-sharing service used in the United States of America, and the introduction of spectrum sharing in the frequency ranging from 3.8~4.2 GHz, based on the United Kingdom framework for spectrum sharing. Specifically, the subjects of topical interest, including the radio station licensing of the spectrum-sharing service system face-to-face multitier user structure, regional frequency allocation, and applicable service types, are discussed. Furthermore, factors to be considered while selecting candidate channels for joint use are suggested, emphasizing their importance for introducing spectrum sharing in Korea and revitalizing the related industrial sectors. In addition, methods of introducing a radio station license system for spectrum sharing, techniques of introducing incentive auctions, and the types of services where spectrum sharing is applicable are discussed.

• The Journal of the Korea institute of electronic communication sciences
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• v.16 no.2
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• pp.247-254
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• 2021

Problems such as a limited frequency resource and interference between adjacent bands have been continuously raised because of rapidly developing wireless technology and communication service. In order to solve that problem, government has been developed and operating the Spectrum Management Intelligent System(SMIS). This paper compares the results simulated by SMIS with the ATDI and the Matlab coded provided by ITU-R for verification of SMIS operating for the public interests. The Recommendation ITU-R P.526, P.1546, and P.1812 among the propagation model loaded in SMIS were chosen because of the relation to the broadcasting service. The comparison and analysis result shows that the outputs derived by SMIS has the small error of less than 1 dB. This research could be utilized for the policy establishment and R&D for the frequency allocation and the interference between adjacent bands.

• The Korean Journal of Air & Space Law and Policy
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• v.27 no.1
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• pp.123-156
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• 2012

This study focuses on the satellite licenses and the requirements for satellite spectrum management (i.e. frequency allocation) in Korean satellite industry via comparative analyses against those cases in other developed countries, in order to provide complementary measures to the domestic satellite policies. The satellite industry is one of the main pursuits of a nation's efforts, and it shows distinct characteristics depending on various factors such as national defense and security. In addition, the industry is determined by the nation's market size as well as its international relationship. Consequently, the present study considers examples from various organizations and nations - including U.S.A, Japan, and ITU - and provides a hybrid policy that is well customized for the domestic market. This study looks at similarities between policies of other countries, and finds any supplements for domestic polices by specifying similar cases in others and analyzing their results. The main purpose of this study, therefore, is to find the best agreement for domestic policy with internal interpretation, rather accepting others. While the licensing method for domestic satellites need not be distinct from that of other nations, the case of using non-Korean licensed satellites must be complemented by the conditions in the domestic market. Furthermore, the spectrum management is essential to the nation's satellite industry since the spectrum is a scarce resource. As such, spectrum management that is carefully designed to incorporate the rapidly changing international market demand is crucial to provide a sufficient supply for domestic space industry. In the present study, we find that auction-like market based approaches together with measures to avoid exclusive uses of the scarce resource (e.g. share, leas and reallocation) would provide an excellent method for the domestic satellite industry.

• Informatization Policy
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• v.30 no.1
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• pp.41-66
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• 2023

This study aims to reveal the direction of municipal ordinances for smart cities, while focusing on 74 municipal ordinances from 72 municipal governments through topic modeling. As a result, the main keywords that show a high frequency belong to establishment and operations of the Smart City Committee. From the result of topic modeling Latent Dirichlet Allocation(LDA), it classifies municipal ordinances for smart cities into eight topics as follows: Topic 1(security for process of smart cities), Topic 2(promotion of smart city industry), Topic 3(composition of a smart city consultative body for local residents), Topic 4(support system for smart cities), Topic 5(management for personal information), Topic 6(use of smart city data), Topic 7(implementation for intelligent public administration), and Topic 8(smart city promotion). As for topic categorization by region, Topics 5, 6, and 8 which are mostly related to the practical operation of smart cities have a significant portion of municipal ordinances for smart cities in the Seoul metropolitan area. Then, Topics 2, 3, and 4 which are mostly related to the initial implementation of smart cities have a significant portion of municipal ordinances for smart cities in provincial areas.

• Journal of Digital Convergence
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• v.15 no.6
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• pp.415-423
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• 2017

This study explored research trends by investigating articles published in the Journal of Korean Society of Fashion Design from 2001 through 2015. English key words and abstracts were analyzed using text mining and topic modeling techniques. The findings are as followings. By the text mining technique, 183 core terms, appeared more than 30 times, were derived from 7137 words used in total 338 articles' key words and abstracts. 'Fashion' and 'design' showed the highest frequency rate. After that, the well-received topic modeling technique, LDA, was applied to the collected data sets. Several distinct sub-research domains strongly tied with the previous fashion design field, except for topics such as fashion brand marketing and digital technology, were extracted. It was observed that there are the growing and declining trends in the research topics. Based on findings, implication, limitation, and future research questions were presented.