• The Journal of Korean Institute of Communications and Information Sciences
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• v.42 no.1
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• pp.77-87
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• 2017

Even though current LTE/LTE-A mobile networks provide enough high data rate and low latency to support conventional wireless services, to support ultra-low delay services, such as virtual reality and remote control, in the next generation mobile communication network, it is required to provide very low delay about several ms. However, in the uplink transmission of the LTE/LTE-A system, the process of scheduling grant is required to obtain uplink resources for uplink transmission from the eNB. The process of granting uplink resources from eNB brings additional fixed latency, which is one of the critical obstacles to achieve low delay in uplink transmissions. Thus, in this paper, we propose a novel uplink transmission scheme called Cut-in uplink transmission, to reduce uplink latency. We provide the performance of the proposed uplink transmission scheme through simulations and show the proposed uplink transmission scheme provides lower uplink transmission delay than conventional uplink transmission scheme in LTE/LTE-A mobile networks.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.2B
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• pp.170-177
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• 2009

In this paper, we propose the structures of the NBTC (Narrow-Beam Trisector Cell) and the WBTC(Wide-Beam Trisector Cell) in which directional antennas both at the base station and at the relay station are used. We analyze and compare total capacity of the both systems taking the co-channel interference into consideration for two channel models. Through analysis, we find the effect of LOS (Lind of Sight) path to the total capacity of NBTC structure and that of WBTC structure. Our work may be useful as a guideline to control the interference for the next generation mobile communication and WiBro systems using multi-hop relays.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.66 no.7
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• pp.1083-1091
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• 2017

As big data technologies have been developed and massive data have exploded from users through various channels, CEO of global IT enterprise mentioned core importance of data in next generation business. Therefore various machine learning technologies have been necessary to apply data driven services but especially recommendation has been core technique in viewpoint of directly providing summarized information or exact choice of items to users in information flooding environment. Recently evolved recommendation techniques have been proposed by many researchers and most of service companies with big data tried to apply refined recommendation method on their online business. For example, Amazon used item to item collaborative filtering method on its sales distribution platform. In this paper, we develop a commercial web service for suggesting music contents and implement three representative collaborative filtering methods on the service. We also produce recommendation lists with three methods based on real world sample data and evaluate the usefulness of them by comparison among the produced result. This study is meaningful in terms of suggesting the right direction and practicality when companies and developers want to develop web services by applying big data based recommendation techniques in practical environment.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• v.9 no.2
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• pp.164-167
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• 2005

Recently, STC techniques have been considered to be candidate to support multimedia services in the next generation mobile radio communications and have been developed the many communications systems in order to achieve the high data rates. In this paper, we propose the Trellis-Coded Differential Space Time Modulation system with multiple symbol detection. The Trellis-code performs the set partition with unitary group codes. The Viterbi decoder containing new branch metrics is introduced in order to improve the bit error rate (BER) in the differential detection of the unitary differential space time modulation. Also, we describe the Viterbi algorithm in order to use this branch metrics. Our study shows that such a Viterbi decoder improves BER performance without sacrificing bandwidth and power efficiency.

• The Transactions of the Korea Information Processing Society
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• v.7 no.2
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• pp.520-528
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• 2000

he speed of microprocessor getting faster, the data transfer width between the microprocessor and the memory becomes a critical part to limit the system performance. So the study of the computer architecture with the high code density is cmerged. In this paper, a tentative Bi-Length Instruction Set Computer(BISC) that consists of 16 bit and 32 bit length instructions is proposed as the high code density 32 bit microprocessor architecture. The 32 bit BISC has 16 general purpose registers and two kinds of instructions due to the length of offset and the size of immediate operand. The proposed 32 bit BISC is implemented by FPGA, and all of its functions are tested and verified at 1.8432MHz. And the cross assembler, the cross C/C++ compiler and the instruction simulator of the 32 bit BISC are designed and verified. This paper also proves that the code density of 32 bit BISC is much higher than the one of traditional architecture, it accounts for 130~220% of RISC and 130~140% of CISC. As a consequence, the BISC is suitable for the next generation computer architecture because it needs less data transfer width. And its small memory requirement offers that it could be useful for the embedded microprocessor.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.7
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• pp.1263-1270
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• 2008

Recently, it is increasing the interest in previous web and web 2.0 which mean differentiation. The previous system is typical Static web based on client and server model, while web 2.0 mean next generation web which web change and evolve fundamentally. In this paper, I suggest that the module on RSS reader available under web 2.0 standards. A currently used RSS feed do correct the part distortion which ran be possible resolve the encoding problem of Hanguel and third-world language. The suggested module is implemented using Ajax. I developed the module for the use of effective contents on web 2.0 through the DragBox module based on the programming on mobility of Ajax and the design and implementation of automatic update module of RSS feed.

• Journal of the Korean Association of Geographic Information Studies
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• v.21 no.4
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• pp.218-237
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• 2018

The purpose of this study is to propose a mid - range low - orbit water disaster monitoring satellite development plan to revolutionize water disaster management infrastructure through securing an independent and leading observation infrastructure and to secure safety against disaster prepared for climate change. Water and water disaster satellites should be able to detect changes in the surface of the ground and observe hydrological factors during daytime, nighttime, and bad weather. In addition, independent technology development should be possible. To do this, we selected C-band image radar payload considering domestic technology and water resources management, and suggested detailed development plan. In this way, it is reflected in the national next-generation mid-satellite 2-phase project plan to secure the basis for building a disaster monitoring system related to wide-area water.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.12 no.12
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• pp.5723-5743
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• 2018

The evolving internet-based services demand high-speed data transmission in conjunction with scalability. The next generation optical network has to exploit artificial intelligence and cognitive techniques to cope with the emerging requirements. This work proposes a novel way to solve the dynamic provisioning problem in optical network. The provisioning in optical network involves the computation of routes and the reservation of wavelenghs (Routing and Wavelength assignment-RWA). This is an extensively studied multi-objective optimization problem and its complexity is known to be NP-Complete. As the exact algorithms incurs more running time, the heuristic based approaches have been widely preferred to solve this problem. Recently the software-defined networking has impacted the way the optical pipes are configured and monitored. This work proposes the dynamic selection of path computation algorithms in response to the changing service requirements and network scenarios. A software-defined controller mechanism with a novel packet matching feature was proposed to dynamically match the traffic demands with the appropriate algorithm. A software-defined controller with Path Computation Element-PCE was created in the ONOS tool. A simulation study was performed with the case study of dynamic path establishment in ONOS-Open Network Operating System based software defined controller environment. A java based NOX controller was configured with a parent path computation element. The child path computation elements were configured with different path computation algorithms under the control of the parent path computation element. The use case of dynamic bulk path creation was considered. The algorithm selection method is compared with the existing single algorithm based method and the results are analyzed.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.22 no.2
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• pp.239-248
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• 2012

VANET (Vehicular Ad-hoc Network) is a type of MANET (Mobile Ad-hoc Network) which is the next-generation networking technology to provide communication between vehicles or between vehicle and RSU (Road Side Unit) using wireless communication. In VANET system, a vehicle accident is likely to cause awful disaster. Therefore, in VANET environment, authentication techniques for the privacy protection and message are needed. In order to provide them privacy, authentication, and conditional, non-repudiation features of the group signature scheme using a variety of security technologies are being studied. In this paper, and withdrawal of group members to avoid frequent VANET environment is suitable for vehicles produced by the group administrator for a private signing key to solve the key escrow problem of a group signature scheme is proposed. We proposed a message batch verification scheme using Bloom Filter that can verify multiple messages efficiently even for multiple communications with many vehicles.

• 전자공학회논문지 IE
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• v.43 no.4
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• pp.28-36
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• 2006

In this paper, an algorithm to classify the 4 motions of arm and a control system to position control the prosthesis are studied. To classify the 4 motions, we use flex sensors which is electrical resistance type sensor that can measure warp of muscle. The flex sensors are attached to the biceps brchii muscle and coracobrachialis muscle and the sensor signals are passed the sensing system. 4 motion of the forearm - flexion and extension, the pronation and supination are classified from this. Also position of forearm is measured from the classified signals. Finally, A two D.O.F prosthesis arm with RC servo-motor is designed to verify the validity of the algorithm. At this time, fuzzy controller is used to reduce the position error by rotary inertia and noise. From the experiment, the position error had occurred within about 5 degree.