• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.13 no.3
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• pp.17-24
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• 2013

In this paper, the measurement data is analyzed and channel characteristics are derived through MIMO Channel measurements at 781MHz considering antenna correlation. 781MHz frequency band currently operates the DTV system, however, it will be allocated new mobile communication frequency band. The channel characteristics at 781MHz seem to be similar existing mobile communication system at 900MHz but quite a different part of the existing research has demonstrated. In addition, the signal procedure of the channel characteristics, considering the correlation of the antenna, for a more accurate prediction research is needed. To avoid interference with Korean DTV broadcasting, we measured channel characteristics in urban areas of Jeju island by channel sounder and $4{\times}4$ antenna. Channel characteristics with antenna correlation were derived based on the measured data in the urban area.

• Journal of Korea Multimedia Society
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• v.16 no.9
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• pp.1077-1088
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• 2013

As broadcasting is the process that a node sends a packet to all nodes in the network. it is basic process used for discovering of a routes to a node and disseminating of control information message in Mobile Ad hoc NETwork (MANET). In this paper, we propose dynamically adjusted probabilistic mechanism based on distance ratio and node density for broadcasting in MANETs. The distance ratio can be calculated as the ratio of the radio strength length to the distance from sender of a node, and node density can be get from 1-hop nodes of neighbours. A mobile node receiving broadcast packets determines the probability of rebroadcasting considering distance ratio and node density of itself. Rebroadcast probability will be set as low value to a node which is located in nearby area of sender and has high 1-hop node density, So it reduces packets transmission caused by the early die-out of rebroadcast packets. Compared with the simple flooding and fixed probabilistic flooding by simulation, our approach shows better performances results. Proposed algorithm can reduce the rebroadcast packet delivery more than 30% without scanting reachability, where as it shows up to 96% reachability compared with flooding.

• Journal of Broadcast Engineering
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• v.12 no.3
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• pp.222-229
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• 2007

According to the advancement of multimedia compression technologies, high quality multi-media services are easily found in common life. Along with this situation, 5.1-channel audio service also has expanded the application area to home theater system and car theater system and consumer can easily take a chance to experience the feeling of 5.1-channel audio. On the other hand, terrestrial DMB service has been launched in Korea from Dec. 2005 as a handhold multi-media broadcasting service. However, multi-channel audio was not considered due to the insufficiency of bandwidth and the handhold usage. Lately, MPEG is standardizing high efficiency multi-channel audio compression technology for handheld broadcasting service, and several trial for application is introduced in Europe. In this paper, we would like to explain multi-channel audio compression technology, describe the implementation of the verification system for the multi-channel audio service over T-DMB and investigate the possibility of further realization of the service.

• Journal of The Institute of Information and Telecommunication Facilities Engineering
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• v.7 no.1
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• pp.23-31
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• 2007

In this paper, UWB system did research about effect that interference effect with neighborhood single equipment or group equipment gets in broadcasting communication service. For this, 2.6425GHz SDMB(Satellite Digital Multimedia Broadcasting) that a special of electric wave interference is near frequency-band including interference of signal by unnecessary radiation level that is radiated in UWB system, and degree of 3.4125GHz broadcasting relay net that is In-band frequency-band and interference effect that get in service analyzed comparison and, modulation of broadcasting relay net and interference measurement equipment used Impulse and OFDM methods. Impulse method was $BER\;=\;1{\times}\;10^{-4}$ that broadcasting signal receiption is possible at 1.4m point because interference effect happens from 2m point in SDMB system, and it was $BER\;=\;1{\times}\;10^{-4}$ that OFDM method receives interference effect from 0.8m point and broadcasting signal receiption is possible at 0.5m point. Also, about Gap-Filler center frequency, In case of space interval more than 0.01m, there was no interference effect. Therefore, for the electric wave of UWB system that is small output applies to system without interference effect in broadcasting communication service, confirmed that UWB system of OFDM method is less interference effect than UWB system of Impulse method.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.9 no.5
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• pp.155-161
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• 2009

This paper proposes a high capacity data hiding method using modulus function of pixel-value differencing (PVD) and least significant bit (LSB) replacement method. Many novel data hiding methods based on LSB and PVD methods were presented to enlarge hiding capacity and provide an imperceptible quality. A small difference value for two consecutive pixels is belonged to a smooth area and a large difference one is located on an edge area. In our proposed method, the secret data are hidden on the smooth area by the LSB substitution method and PVD method on the edge area. From the experimental results, the proposed method sustains a higher capacity and still a good quality compared with other LSB and modified PVD methods.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.8 no.3
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• pp.35-45
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• 2008

Realtime visibility measurement using camera is a new method which can collect some realtime visibility data similar to those of the human eyes, and can replace the existing methods using the expensive optical equipment. There have been a few attempts to measure visibility by extracting depth and three-dimensional structure under bad weather conditions. However, if there are many movements of objects in the image, these approaches seem to be inappropriate. In addition, the realtime visibility measurement will require a relatively simple and fast processing. Typically the contrast degrades exponentially in the bad weather. Therefore, in this paper we propose an easy and quick method that extract contrast from images using a moving area filter and measure visibility by mathematically modelling of the relationship between image contrast and visibility. The moving area filter is used for removing the area of the sky and moving objects that affect visibility measurement on images. The method proposed here can make possible not only realtime visibility measurement from images taken by CCD cameras, but also steady visibility measurement by using the moving area filter in case of much traffic on the road.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.17 no.1
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• pp.41-51
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• 2017

Recently, Broadband Internet service in the rural area is deployed actively so it will be needed to identify the factors influencing success for continuous spread. In this paper, we explain the users'satisfaction of BcN for rural area and verify success factors such as obstacles the digital divide through the empirical analysis. We select basic variables from Information System (IS) Success Model and add specific variables from former research about overcoming digital divide. The results show that system quality has a significant influence on satisfaction. Use and satisfaction have an impact on eliminating the digital divide in rural area. Based on the findings, academic and practical implications for establishing Broadband Service in rural area are also discussed.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.37 no.6
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• pp.514-520
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• 1992

Performance of direct seeded paddy rice in ridged dry soil was evaluated at different seeding methods (broadcasting, drilling, and seeding in group) and seeding rates (4, 6, and 8kg /10a). The number of maximum tillers at broadcasting and drilling of seeds was higher than that at seeding in group. At broadcasing and drilling the number of maximum tillers at seeding rate of 6kg /10a was greater than that at 4 or 8kg /10a, but at seeding in group the number of maximum tillers increased with seeding rates. Among the seeding methods there were no differences in the number of seedlings per unit area, culm and panicle lengths, and productive tiller ratio, but heading date at seeding in group was delayed by a day compared with broadcasting or drilling. At heading stage leaf area index(LAI) and dry matter production at broadcasting of seeds were higher compared with drilling and seeding in group, but light transmission ratio at drilling and seeding in group was higher than that at broadcasting of seeds. Although the number of seedlings increased with seeding rates, LAI and dry matter production at heading stage, culm and panicle lengths, and productive tiller ratio were not different among the seeding rates. There were no differences in the number of panicles and spikelets per unit area, 1,000 grain weight, yield, and harvest index among the seeding methods. The number of spikelets per panicle at seeding in group was higher, but percent ripened grains was lower compared with broadcasting and drilling. There were no significant differences in the number of panicles and spikelets per panicle and unit area, percent ripened grains, and harvest index among the seeding rates, but yield at seeding rate of 6kg /10a was higher than at 4 or 8kg /10a. There were no significant differences in tiller length, bending moment, and fresh weight of tiller among the seeding methods. Breaking strength was lower in the order of seeding in group, drilling, and broadcasting of seeds. However, lodging index was similar among the seeding rates and lodging was not occurred in the field. There was a significant interaction in the cellulose, hemicellulose, and lignin contents of culm base between seeding methods and seeding rates.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.12 no.2
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• pp.135-143
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• 2012

This paper suggests the optimal blood distribution center algorithm that satisfies the minimum total transportation cost and within the allowable distribution time $T^*$. Zhang and Yang proposes shifting the location of each point that has less than the average distance of two maximum distance points from each point. But they cannot decide the correct facility location because they miscompute the shortest distance. This algorithm computes the shortest distance $l_{ij}$ from one area to another areas. Then we select the $v_i$ area to thecandidate distribution center location such that $_{max}l_{ij}{\leq}L^*$ and the $v_i$ such that $l_{ij}-L^*$ area that locates in ($v_i,v_k$) and ($v_j,v_l$) from $P_{ij}=v_i,v_k,{\cdots},v_l,v_j$ path and satisfies the $_{max}l_{ij}{\leq}L^*$ condition. Finally, we decide the candidate distribution area that has minimum transportation cost to optimal distribution area.

• Journal of Broadcast Engineering
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• v.8 no.3
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• pp.217-227
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• 2003

This paper describes an implementation of the slide-show functionality, which is one of the services that can be provided by the Digital Multimedia Broadcasting (DMB). While the existing analog radio broadcasting services provide audio only, DMB slide-show is the functionality that can deliver still images associated with the audio. For example, it can deliver the photographs of the singer, album cover images, or the lyrics of the song that correspond to the audio. There are two modes for the transmission of the slide-show. Firstly. the program-associated data (PAD) field within the DMB audio frame can be utilized and secondly, the slide-show data can be transmitted, after being multiplexed, with other service data as individual data stream separated from the audio. This paper describes PC-based implementations of a transmitter-side module that inserts slide-show data into the PAD area within audio bitstream and a receiver-side application module that plays the slide-show through decoding the PAD within the received audio bitstream and demonstrates their validity through experiments.