• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.17 no.5
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• pp.25-33
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• 2017

NOMA (Non-orthogonal multiple access) system becoming a strong candidate for 5G cellular system of its high spectral efficiency. This paper considers an optimal power allocation scheme to minimize the outage probability of a user relay based cooperative NOMA system. We first derive the outage probabilities of the relay user (RU) and the destination user (DU) with selection combining. Based on these probabilities, the outage probability of the cooperative NOMA system is obtained. The analytical results are verified by Monte Carlo simulation. It is noticed that the outage probability of cooperative NOMA system has a convex function, the optimum power allocation coefficient, which satisfied the minimum outage probability, is calculated. Numerical examples show that the optimal power allocation coefficient increases with the required capacity of DU. While the capacity of DU is fixed, we noticed that the increase of the required capacity of RU decreases the optimal power allocation coefficient.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.12 no.1
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• pp.17-27
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• 2012

Broadcast-based data dissemination has become a widely accepted approach of communication in the mobile computing environment. However, with a large set of data items, the expected delay of receiving a desired data increases due to the sequential nature of the broadcast channel. This paper explores the issue of designing proper data allocation on multiple broadcast channels to reduce this wait time, and proposes a new data allocation scheme named near optimal data allocation(NODA). The proposed scheme first partitions all data items in K group based on the theoretical lower-bound of the average expected delay to determine data items which each broadcast channel has to broadcast. Then, NODA further partitions each group of data items in B groups using extended dynamic programming algorithm to broadcast data items allocated on the same broadcast channel in different frequencies. The proposed scheme is capable of minimizing the average expected delay time since it can broadcast data items allocated on the same channel reflecting their popularities.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.17 no.2
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• pp.135-140
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• 2017

The demand for aquatic products in the domestic and overseas is increased, so that the aquaculture industry can achieve high performance by controlling and standardizing the production even with a relatively small amount of resources compared with existing fisheries. However, traditional method has problems of low productivity such as natural disasters and ecosystem pollution, and it is necessary to develop a new culture system that can move to the optimal culture site. In order to find the optimal location, you need to collect and analyze the necessary data such as temperature and DO in real time. Data analysis was performed by using K-means clustering method based on machine learning, so that it was possible to decision when and where to move the farm by repeated unsupervised learning. The proposed research could solve the problems of low productivity such as natural disasters and ecosystem pollution if applied to regressive fish farmers.

• International Journal of Internet, Broadcasting and Communication
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• v.13 no.2
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• pp.244-259
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• 2021

The economic value of personal information has its importance as an objective measure of valuation in commercial, legal, and policy areas. Until recently, however, personal information subjects have not properly recognized the economic value of personal information, which has led to the inability to exercise the right to self-determination of personal information by unconsciously agreeing to the terms and conditions of personal information service without recognizing the value of personal information provided to the service provider when subscribing to a specific service. Therefore, we will examine the methodologies for calculating the economic value of personal information and the practical guarantee of the right to self-determination of personal information and analyze the economic value of personal information through a survey. Also, we would like to propose various ways for the subject of personal information with limited cognitive resources to visually accept the economic value of personal information required by the terms and conditions and suggest the optimal visualization of personal information economic value to exercise the right to self-determination of personal information. To do so, in this paper, we have conducted two survey experiments to estimate the economic value of personal information. Based on the price of personal information by category retrieved from surveys, we have visualized the price of personal information in various forms and asked respondents to choose the optimal infographic that best represents the value of personal information visually. As a result, we have proposed an optimal usage of the infographic to 'nudge' information subjects about their right to self-determination of personal information, therefore opening the possibility of diminishing privacy paradox.

• ETRI Journal
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• v.32 no.2
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• pp.273-280
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• 2010

The overall channel capacity of a multihop wireless path drops progressively over each hop due to the cascading effect of noise and interference. Hence, without optimal rate adaptation, the video quality is expected to degrade significantly at any client located at a far-edge of an ad-hoc network. To overcome this limitation, decoding and forwarding (DF), which fully decodes codewords at each intermediate node, can be employed to provide the best video quality. However, complexity and memory usage for DF are significantly high. Consequently, we propose syndrome-based partial decoding (SPD). In the SPD framework an intermediate node partially decodes a codeword and relays the packet along with its syndromes if the packet is corrupted. We demonstrate the efficacy of the proposed scheme by simulations using actual 802.11b wireless traces. The trace-driven simulations show that the proposed SPD framework, which reduces the overall processing requirements of intermediate nodes, provides reasonably high goodput when compared to simple forwarding and less complexity and memory requirements when compared to DF.

• Proceedings of the Korea Contents Association Conference
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• 2007.11a
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• pp.270-273
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• 2007

The overlay multicast that has been recently presented as an alternative for the IP multicast has been getting much persuasion by the advancement of the network techniques to enforce routing in application-level. But, The overlay multicast is a problem of delay and the load of the traffic control. In this paper, we suggested to an effective transmission routing tree between users based on overlay multicast of Internet broadcasting Service. And we evaluated an optimal value of transmission delay about Internet broadcasting using this suggest model.

• Proceedings of the IEEK Conference
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• 2002.07c
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• pp.1940-1943
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• 2002

In this paper, we presented the design and implementation of 155Mbps satellite Modem adaptively compensated against the rain attenuation. In order to compensate the rain attenuation over high-speed satellite ink, the adaptive coding schemes with variable coding rates and the pragmatic TCM that can be decoded both the QPSK and TC-8PSK using same Viterbi decoder was studied and analyzed. The pragmatic TCM with rate 213, selected to the optimal parameters for implementation, was modeled by VHDL in this paper. The key design issues are how to achieve a high data rate and how to integrated into a single ASIC chip various functions such as the different data rates, Scrambler/descrambler, Interleaver, Encoder/decoder, and BPSK/QPSK/8PSK modulator/demodulator. The implemented 155M0ps adaptive MODEM has the simplified interface circuits among the many functional blocks, and parallel processing architecture to achieve the high data rate. This 155Mbps adaptive MODEM was designed and implemented by single ASIC chip with the 0.25 $\mu\textrm{m}$ CMOS standard cell technology.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.8 no.3
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• pp.1-7
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• 2008

This paper proposes a new QRD-LS adaptive algorithm with computational complexity of O(N). The main idea of proposed algorithm(D-QR-RLS) is based on the fact that the computation for the unit vector of is made from the process during Givens Rotation. The performance of the algorithm is evaluated through computer simulation of FIR system identification problem. As verified by simulation results, this algorithm exhibits a good performance. And, we can see the proposed algorithm converges to optimal coefficient vector theoretically.

• Journal of The Korean Society of Grassland and Forage Science
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• v.9 no.2
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• pp.108-112
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• 1989

To determine optimal plant density of forage rape in southern areas of Korea, Velox, the highest yielding variety among seventeen introduced varieties of forage rape, was grown under five different plant densities. The results obtained are summarized as follows: 1. Yield components such as stem diameter, number of main stem,leaves, number of branches and number of branch leaves and fresh yield were highest at the plots with 50cm row spacing and 30cm plant spacing. 2. Dry matter yield, content of crude protein, IVDMD and digestible dry matter yield were highest at the plots of broadcasting. 3. Since plants under high density were high in plant length and small in stem diameter, contents of crude fiber such as NDF, ADF, cellulose and lignin were lowest at the plots of broadcasting.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.17 no.9 s.112
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• pp.795-803
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• 2006

In this paper, we studied hierarchical channel coding scheme using unequal error protection method fur consecutively broadcastingservice under the rain attenuation of Ka band satellite broadcasting. Unlike time-sharing methods, which are design for different channel coding scheme in according to different modulation, unequal error protection method is made in such way that minimum distance between signals are different for importance of signals with same modulation. Consequently we proposed optimal method according to performance analysis.