• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2016.10a
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• pp.66-69
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• 2016

In this paper, we suggests a Ka-band LNB considering next-generation UHD satellite TVRO. Since Ka-band has grater attenuation than Ku-band in atmosphere, we designed the low-noise down-converter to improve receiving sensitivity and to extend a dynamic range of receiver. It aims to compensate a quality of ultra high definition transmission signal for rainfall. The low-noise block diagram consists of a three-staged amplifier (LNA), band-pass filter for deleting image (BPF), mixer and IF when considering nonlinear characteristics in the receiver RF front end module. Also, we showed a LNB through optimization processes affecting dynamic range directly in receiver FEM. Asa resuly of experiment, the gain of low-noise down-converter show between 58.5dB and 60.7dB, the noise figure has a high characteristic as 1.38dB. Finally, the phase noise of local oscillator is -63.10dBc at 100MHz offset frequency.

• Journal of The Korean Society of Agricultural Engineers
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• v.63 no.2
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• pp.11-18
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• 2021

A community-centered smart village process model was developed through the theoretical review of the rural field forum. By analyzing the difference in technology demand according to the digital capabilities of leaders by community type, village types were classified and detailed technologies were defined. The smart village process was proposed to enable residents to operate autonomously by inducing continuous interest and participation of local residents through the conception stage, planning stage, implementation and self-reliance stage, and allowing them to cooperate together. The business model canvas was reconstructed to be used in the workshop. It was applied to the village of Yesan-gun. As a result of running a resident workshop using the business model Cambus, the lack of resident awareness and illegal garbage dumping were presented as the first problems to be solved. The value of the village was set as 'a village that is clean and clean with a sense of residents, and a good place to live', and users were expressed as 'family' and 'outsiders'. It was suggested that we meet frequently to convey the value of the village by using broadcasting and announcements as a channel to convey the value. Core activities were to cultivate residents' consciousness, such as implementing a campaign against illegal garbage dumping, and to establish and guide separate collection sites. When a garbage collection center is installed, it was estimated that around 2 million won per month for management costs, and it was investigated that it was possible to spend an hour or so twice a month to solve the problem of illegal dumping. If a method to derive village projects based on the derived business model canvas is developed in the future, it will be more practical.

• The Journal of the Convergence on Culture Technology
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• v.9 no.3
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• pp.495-508
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• 2023

To compare whether broadcast fact-checking news, which aims to overcome the limitations of objective reporting, ensures fairness, we analyzed 227 fact-checked news stories aired on the main news of KBS, MBC SBS, TV Chosun, JTBC MBN, and YTN from January 1, 2022 to May 31, 2022, when the 20th presidential and local election campaigns were held. The analysis showed clear differences in fact-checking targets and narratives by broadcasters. In general, MBC, JTBC,and YTN were more likely to favor liberal parties such as the Democratic Party, while TV Chosun had a lot of narratives favoring the conservative camp. SBS and MBN were relatively neutral. KBS seemed to be trying to remain outwardly neutral. SBS and TV Chosun were the most active in fact-checking, but they covered a wide range of issues and were characterized by a bias toward contextualizing issues that viewers were curious about, rather than clarifying the facts. The projection of ideological bias by broadcasters in fact-checking narratives is a challenge that needs to be overcome.

• The Journal of the Korea Contents Association
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• v.22 no.8
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• pp.274-287
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• 2022

Competition in the broadcasting market is intensifying as OTT services are spreading. And Korea is positioned as a competent international contents supply base. This can be helpful for the domestic contents production industry. However, it can result in being incorporated as a subcontractor in the global video industry. Therefore, it is necessary for Korean OTT operators to expand their market upto overseas and maintain competitiveness by linking content competitiveness to the sales expansion. This study was conducted to reduce the risk and encourage implementation through feasibility analysis of overseas business of domestic OTT operators. The North American market was selected as a region with high potential through in-depth interviews with experts and literatures review. And it was confirmed that the partnership with local platform is effective. Then, the sales and input costs were estimated, and business was evaluated using the net present value method. Totally 18 scenarios were created using multiple estimates for copyright cost, subscribers, and rate, which are highly uncertain. From the analyses, 8 scenarios were found to be acceptable. And copyright cost has the greatest impact on business success, followed by rates and subscribers.

• Korea journal of population studies
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• v.20 no.2
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• pp.161-180
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• 1997

There are about 400, 000 Korean ethnics living in Central Asia. Most of Koreans in Central Asia are leading a stable middle class life mostly engaged in farm work. With increase of educational attainment of their children, a number of Koreans are launching into political and academic circles as well as in the cultural world or the press. In recent years, however, the countries in this area(Uzbekistan and Kazakstan) for this study advocate an ethnic united policy to stabilize the politics and society and to carry out efficient transformation from the former socialistic economy to a market oriented economy. In addition, they are trying to recover the culture and the language of each nation which has been forgotten in the assimilation of Russia policy. Koreans have difficulty in adaption to this kind of change. In fact, a number of Koreans lost traditional culture and could not speak their mother language - Korean. Although they more or less maintain national consciousness, they recognize Uzbekistan or Kazakstan as their nation politically. They associated with North Korea unilaterally before the launching of the Perestroika policy. But after the Seoul Olympics held in 1998, there was movement to know and understand South Korea. There has been increased in the investment by Korean companies in Central Asia. Now, what is an alternative idea for Korean community consciousness\ulcorner It can be summarized as follows: 1) The increase of aid to Korean education institute : Considering the last few decades of Russia's strong racial assimilation policy, which leads most Koreans to lost their language and national culture, the priority should go to Koreans education. 2) Local Korean press support : Though Korean newspaper are published and Korean broadcasting is on the air currently in Uzbekistan and Kazakstan, they are suffering from qualified staff and poor financial status. Therefore, positive support should be established for these Korean mass communication media outlets to recover their own function and expand their dissemination powers quickly. 3) Research on the actual condition for Korean Community : It is essential to directly examine the local Korean community's regional distribution, population structure, Korean group's formation and operation, social and cultural understanding, racial consciousness, hope for their mother land and much more. 4) Increase of mother land and education opportunity : To stir up national culture and national consciousness within the Korean community, it is necessary to expand continuous opportunities for mother land visits and education training for local Koreans, especially for second and third generations.

• Korea journal of population studies
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• v.10 no.1
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• pp.50-69
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• 1987

There are about 400, 000 Korean ethnics living in Central Asia. Most of Koreans in Central Asia are leading a stable middle class life mostly engaged in farm work. With increase of educational attainment of their children, a number of Koreans are launching into political and academic circles as well as in the cultural world or the press. In recent years, however, the countries in this area(Uzbekistan and Kazakstan) for this study advocate an ethnic united policy to stabilize the politics and society and to carry out efficient transformation from the former socialistic economy to a market oriented economy. In addition, they are trying to recover the culture and the language of each nation which has been forgotten in the assimilation of Russia policy. Koreans have difficulty in adaption to this kind of change. In fact, a number of Koreans lost traditional culture and could not speak their mother language - Korean. Although they more or less maintain national consciousness, they recognize Uzbekistan or Kazakstan as their nation politically. They associated with North Korea unilaterally before the launching of the Perestroika policy. But after the Seoul Olympics held in 1998, there was movement to know and understand South Korea. There has been increased in the investment by Korean companies in Central Asia. Now, what is an alternative idea for Korean community consciousness\ulcorner It can be summarized as follows: 1) The increase of aid to Korean education institute : Considering the last few decades of Russia's strong racial assimilation policy, which leads most Koreans to lost their language and national culture, the priority should go to Koreans education. 2) Local Korean press support : Though Korean newspaper are published and Korean broadcasting is on the air currently in Uzbekistan and Kazakstan, they are suffering from qualified staff and poor financial status. Therefore, positive support should be established for these Korean mass communication media outlets to recover their own function and expand their dissemination powers quickly. 3) Research on the actual condition for Korean Community : It is essential to directly examine the local Korean community's regional distribution, population structure, Korean group's formation and operation, social and cultural understanding, racial consciousness, hope for their mother land and much more. 4) Increase of mother land and education opportunity : To stir up national culture and national consciousness within the Korean community, it is necessary to expand continuous opportunities for mother land visits and education training for local Koreans, especially for second and third generations.

• Journal of Intelligence and Information Systems
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• v.28 no.1
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• pp.45-68
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• 2022

The central and local governments of the Republic of Korea provided information necessary for disaster response through wireless emergency alerts (WEAs) in order to overcome the pandemic situation in which COVID-19 rapidly spreads. Among all channels for delivering disaster information, wireless emergency alert is the most efficient, and since it adopts the CBS(Cell Broadcast Service) method that broadcasts directly to the mobile phone, it has the advantage of being able to easily access disaster information through the mobile phone without the effort of searching. In this study, the characteristics of wireless emergency alerts sent to Seoul during the past year and one month (January 2020 to January 2021) were derived through various text mining methodologies, and various types of information contained in wireless emergency alerts were analyzed. In addition, it was confirmed through the population mobility by age in the districts of Seoul that what kind of influence it had on the movement behavior of people. After going through the process of classifying key words and information included in each character, text analysis was performed so that individual sent characters can be used as an analysis unit by applying a document cluster analysis technique based on the included words. The number of WEAs sent to the Seoul has grown dramatically since the spread of Covid-19. In January 2020, only 10 WEAs were sent to the Seoul, but the number of the WEAs increased 5 times in March, and 7.7 times over the previous months. Since the basic, regional local government were authorized to send wireless emergency alerts independently, the sending behavior of related to wireless emergency alerts are different for each local government. Although most of the basic local governments increased the transmission of WEAs as the number of confirmed cases of Covid-19 increases, the trend of the increase in WEAs according to the increase in the number of confirmed cases of Covid-19 was different by region. By using structured econometric model, the effect of disaster information included in wireless emergency alerts on population mobility was measured by dividing it into baseline effect and accumulating effect. Six types of disaster information, including date, order, online URL, symptom, location, normative guidance, were identified in WEAs and analyzed through econometric modelling. It was confirmed that the types of information that significantly change population mobility by age are different. Population mobility of people in their 60s and 70s decreased when wireless emergency alerts included information related to date and order. As date and order information is appeared in WEAs when they intend to give information about Covid-19 confirmed cases, these results show that the population mobility of higher ages decreased as they reacted to the messages reporting of confirmed cases of Covid-19. Online information (URL) decreased the population mobility of in their 20s, and information related to symptoms reduced the population mobility of people in their 30s. On the other hand, it was confirmed that normative words that including the meaning of encouraging compliance with quarantine policies did not cause significant changes in the population mobility of all ages. This means that only meaningful information which is useful for disaster response should be included in the wireless emergency alerts. Repeated sending of wireless emergency alerts reduces the magnitude of the impact of disaster information on population mobility. It proves indirectly that under the prolonged pandemic, people started to feel tired of getting repetitive WEAs with similar content and started to react less. In order to effectively use WEAs for quarantine and overcoming disaster situations, it is necessary to reduce the fatigue of the people who receive WEA by sending them only in necessary situations, and to raise awareness of WEAs.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39B no.11
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• pp.730-742
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• 2014

In the case of On-demand routing protocol in cognitive radio ad-hoc networks, broadcasting of control packets may occur common control channel overload and packet collisions during the routing procedure. This situation is to increase the overhead of path finding and also limited to find the accurate and reliable path. Since reliable channel and path finding is restricted, path life time is shorten and path reliability is reduced. In this paper, we propose a new routing algorithm that reduces control channel overhead and increases path life time by considering the probability of appearance of primary user and channel status of neighbor nodes. Each node performs periodic local sensing to detect primary user signal and to derive primary user activity patterns. The probability of primary appearance on the current channel and the channel status can be obtained based on the periodic sensing. In addition, each node identifies the quality of the channel by message exchange through a common channel with neighbor nodes, then determines Link_Levels with neighbor nodes. In the proposed method, the Link Level condition reduces the number of control messages that are generated during the route discovery process. The proposed method can improve path life time by choosing a path through Path_Reliability in which stability and quality are weighted depending on the location. Through simulation, we show that our proposed algorithm reduces packet collisions and increases path life time in comparison with the traditional algorithm.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.19 no.6
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• pp.630-639
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• 2008

In this paper, we investigate the cause of throughput degradation on the wireless local area network(WLAN) and the reason of interference level change attributed to the spanned frequency in the presence of electromagnetic interference. We also measured and quantified the electric field strength of interference which yields the abrupt change of the throughput. Two units of WLAN and one unit of AP(Access Point) are configured to maintain the radio link. As the sources of interference, both the co-channel and adjacent-channel interference are considered and the critical values of electric field are provided for each case. Our experimental observations show that the signal strength generated from these interference sources is at most less than 54 dBuV/m @3 m in order to coexist between WLANs and other low power radio devices without any noticeable throughput decreases. Based on our empirical results, as far as 802.11b WLAN is concerned, we believe that the current domestic limit of the signal strength for an extremely low power radio device, 30.9 dBuV/m @3 m, can be increased as much as 23.1 dB.

• Journal of Broadcast Engineering
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• v.9 no.1
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• pp.83-90
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• 2004

DVB-MHP recommends that NPT(normal play time) be used as the times of stream events. NPT is the local time within an event(TV program). But we found that commercial transport stream (TS) generators and middlewares for DVB-MHP settop boxes are not ready to support the use of NPT by applications. In particular, TS generators do not create NPT reference descriptors needed to reconstruct NPT at the TV receiver. This situation is undesirable because program providers cannot experiment with the idea of synchronized applications. So we have implemented a TS generator that inserts NPT reference descriptors to TS and MyGetNPT API to approximately reconstruct NPT. STC (system time clock) is needed to reconstruct NPT, but Xlets are not allowed to read it. So, we approximate STC by using PCR (program clock reference) and the Java system tune. In this method, the stream generator extrats PCRs from an existing TS and inserts them into null TS packets in the form of MPEG sections, which can be read by Xlets. Because PCRs are displaced into new positions in TS, their values should be adjusted based on the time intervals between the original positions and the new positions. We implemented a synchronized application by using our TS generator and MyGetNPT API, where the task of stream events are to display graphic images. We found that graphic images are displayed where 240 ㎳ from their intended time, where 240ms is a human tolerance for the synchronization skew between graphic image and video.