• The Journal of Korean Institute of Communications and Information Sciences
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• v.39C no.9
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• pp.757-766
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• 2014

To compensate signal loss due to the channel blockage in satellite communication link, we propose a cooperative communication scheme for OTM(On-The-Move) terminal in next generation satellite communication systems. The proposed scheme configures cooperation subnet with adjacent OTM terminal with the help of ground communication equipment. Shared data is spread by orthogonal spreading code, then the spread sequences are transmitted simultaneously. The receiver combines the power of received signals by EGC(Equal gain combining). The OTM terminal blockage channel is modeled by 2-state Markov chain. We evaluate the bit error rate according to the blockage channel of the channel state for the performance analysis of the proposed scheme. As a result, the proposed scheme shows better BER performance than traditional scheme with the help of subset members. In particular, the proposed scheme shows superior performance as the channel block probability is higher. However, as the number of subset members is increasing, there is a constraint because of the higher multiple access interference.

• Journal of the Korean association of regional geographers
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• v.11 no.5
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• pp.391-404
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• 2005

This paper attempts to show the status and network characteristic of regional innovation support agencies(company support agencies and R&D institutes, RISA) which play an important role in the regional system of innovation in Daegu City, using questionnaire data. Most of these agencies were established in 1990s and tend to locate in Buk-Gu and Dalsu-Gu, being major local universities which retain a large number of R&D and industry support agencies. The business areas of the agencies are largely associated with business training and applied research. Their major role is to provide the information that local firms need to acquire. It shows that they have relationships with 1 to 5 agencies, primarily in the form of informal network, for the purpose of sharing information and knowledge about science/technology and market trend. There are not many spin-offs from RISA. But most of spin-offs from RISA are located in Daegu City and maintain cooperative relationships with their parent organization primarily in the form of formal network. The main purpose of cooperative relationships with RISA is to interchange knowledges about technology.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.12 no.6
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• pp.2595-2618
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• 2018

In this paper, we investigate secure communication with the presence of multiple eavesdroppers (Eves) in a two-tier downlink dense heterogeneous network, wherein there is a macrocell base station (MBS) and multiple femtocell base stations (FBSs). Each base station (BS) has multiple users. And Eves attempt to wiretap a macrocell user (MU). To keep Eves ignorant of the confidential message, we propose a physical-layer security scheme based on cross-layer cooperation to exploit interference in the considered network. Under the constraints on the quality of service (QoS) of other legitimate users and transmit power, the secrecy rate of system can be maximized through jointly optimizing the beamforming vectors of MBS and cooperative FBSs. We explore the problem of maximizing secrecy rate in both non-colluding and colluding Eves scenarios, respectively. Firstly, in non-colluding Eves scenario, we approximate the original non-convex problem into a few semi-definite programs (SDPs) by employing the semi-definite relaxation (SDR) technique and conservative convex approximation under perfect channel state information (CSI) case. Furthermore, we extend the frame to imperfect CSI case and use the Lagrangian dual theory to cope with uncertain constraints on CSI. Secondly, in colluding Eves scenario, we transform the original problem into a two-tier optimization problem equivalently. Among them, the outer layer problem is a single variable optimization problem and can be solved by one-dimensional linear search. While the inner-layer optimization problem is transformed into a convex SDP problem with SDR technique and Charnes-Cooper transformation. In the perfect CSI case of both non-colluding and colluding Eves scenarios, we prove that the relaxation of SDR is tight and analyze the complexity of proposed algorithms. Finally, simulation results validate the effectiveness and robustness of proposed scheme.

• Journal of the Korea Society of Computer and Information
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• v.26 no.3
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• pp.89-97
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• 2021

The objective of this study is to propose an operation management strategy for the connectivity which are the designated and managed in sector of the transportation and logistics on the national critical infrastructures. The industrial structure is becoming advanced. The national critical infrastructure managed by the shows forms of the cooperative connection and collaborative R&D. Also, in-depth and specific analysis for the disaster safety budget are implemented to consideration for the R&D life cycle. The government responsibility are expanded comprehensively. Needs are exchanging life styles by the economic and safety demands. At this trends, this study encourage facility maintenance and scientific management to the public service. Throughout the result of this study, national critical infrastructure are implementing for protection plan of the sustainable maintenance and management. And, we have to prepare and implement for the consideration of the characteristics through comprehensive guidelines. This study contributes to the disaster and safety management by proposed an operation strategy of the cooperative connection in the sector of transportation and logistic sector on the national critical infrastructure.

• Transactions of the Korean Society of Automotive Engineers
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• v.17 no.3
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• pp.54-61
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• 2009

Lane keeping assistant system (LKAS) could save thousands of lives each year by maintaining lane position and is regarded as a promising active safety system. The LKAS is expected to reduce the driver workload and to assist the driver during driving. This paper proposes a model based predictive controller for the LKAS which requires cooperative driving between the driver and the assistance system. A Hardware-In-the-Loop-Simulator (HILS) is constructed for its evaluation and includes Carsim, Matlab Simulink and a lane detection algorithm. The single camera is mounted with the HILS to acquire the monitor images and to detect the lane markers. The simulation is conducted to validate the LKAS control performance in various road scenario.

• Transactions of the Korean Society of Automotive Engineers
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• v.17 no.1
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• pp.50-57
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• 2009

Lane Keeping Assistant Systems (LKAS) require the cooperative operation between drivers and active steering angle/torque controllers. An LKAS is proposed in this study such that the desired reference path generation (DRPG) system generates the desired path to minimize the trajectory overshoot. Based on the reference path from the DRPG system, an optimal controller is designed to minimize the cost function. A HIL (Hardware In the Loop) simulator is constructed to evaluate the proposed LKAS system. The single camera is mounted on the simulator and acquires the monitor images to detect lane markers. The performance of the proposed system is evaluated by HIL system using the Carsim and the Matlab Simulink.

• Journal of Dairy Science and Biotechnology
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• v.35 no.1
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• pp.39-45
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• 2017

The market for lactose-hydrolyzed milk is growing due to an increased awareness of lactose intolerance, and increased market interest for modified milk with health claims. The aim of this study was to compare the quality characteristics of 2% lactose-hydrolyzed milk with its lactose hydrolysis rate, with the goal of applying the method to dairy product monitoring in the future. We observed that the freezing point of milk significantly decreased with increasing lactose hydrolysis rate. A linear relationship was found between lactose concentration and freezing point, following the equation (y=-50.416x + 767.91). However, no significant changes were observed in other physicochemical properties of the milk (pH, titratable acidity, total solids and color) (p<0.05). In conclusion, we could predict the residual lactose content quickly and easily in 2% low fat milk by measuring its freezing point. This could represent an easy means for assessing the lactose hydrolysis rate of dairy products.

• The Journal of the Korea Contents Association
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• v.15 no.11
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• pp.559-570
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• 2015

As national R&D is increased in scale, technology transfer has garnered more attention in terms of utilizing R&D outcomes. In this study, we analyzed influencing factors to technology transfer, as a way of utilizing R&D results, using data on national R&D. The analyses was performed with 3 subjects: university, government research institute and industry. When royalty is used as a dependent variable to measure the performance outcomes of technology transfers, the analysis showed that R&D funds have positive influence on all three subjects. In terms of government research institute, the influence was significant whether the location is the capital area or Daejeon city. With regards to industry, factors such as whether the project is a cooperative research, applied research, and the research to technology transfer period were found to have remarkable influence. On the other hand, when the number of cases of technology transfer was used as a dependent variable, the analysis indicated that R&D funds have significant impact on university, while for government research institute, the significant influencing factors include both R&D funds and the research to technology transfer period, and for industry have positive influence on applied research. It is therefore necessary to make differentiated policies considering the R&D organizations in order to improve the efficiency of technology transfer performance.

• Journal of Broadcast Engineering
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• v.13 no.6
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• pp.951-961
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• 2008

Cooperative diversity is a cooperative technique which exploits user diversity by decoding the combined signal of the relayed signal and the direct signal in wireless multi-hop networks. Using the cooperation, the performance of the network system can be improved because cooperative diversity which is very strong against the fading channels can be achieved. In this paper, we propose the technique that provides the enhanced visual quality of the reconstructed video using the cooperative diversity with the FMO which is the error resilience tool of H.264/AVC standardization over wireless networks. The eye-tracker can detect the gaze point of user and transmit the gaze information to the nodes. After receiving the gaze information of user, each node performs ROI encoding according to the received gaze information. After encoding, video sources are divided into ROI and Non-ROI. Through the simulation results, the better visual quality of the reconstructed video is achieved when ROI and Non-ROI are transmitted through different channels.

• Journal of Korea Game Society
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• v.20 no.1
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• pp.57-66
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• 2020

The goal is to implement AI using reinforcement learning, which replaces the less favored Supporter in MOBA games. ML_Agent implements game rules, environment, observation information, rewards, and punishment. The experiment was divided into P and C group. Experiments were conducted to compare the cumulative compensation values and the number of deaths to draw conclusions. In group C, the mean cumulative compensation value was 3.3 higher than that in group P, and the total mean number of deaths was 3.15 lower. performed cooperative play to minimize death and maximize rewards was confirmed.