• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.8
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• pp.1860-1868
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• 2009

As general use of Mobile devices, the integration operations between the Home network is active. For popularization of Home network interface of normalizing in user's use convenience offer must, and developer must be able to cope sensitively in change development and requirement, hereafter such as maintenance with normalized interface environment. In the case of Home network, because several terminal information devices have to be used to a Home server, user establishment and exclusion should be easy and should adapt fast in requirement alteration and maintenance. In this paper, we designed and implemented mobile home network components with applied efficient information transmission interface that can be applied to the various application of OSGi platform. These components can respond quickly of user requirements and maintenance and that can be reuse and evolved.

• Journal of Korea Society of Industrial Information Systems
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• v.24 no.5
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• pp.53-64
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• 2019

The term 're-use' here signifies the re-use of end-of-life products without changing their form after they have been thoroughly inspected and cleaned. In the re-use network model, the distributor determines the product order quantity on the network through which new products are received from the suppliers or products are supplied to the customers through re-use of the recovered products. In this paper, we propose a reusable network model for reusable products that considers the total logistics cost from the forward logistics to the reverse logistics. We also propose a reusable network model that considers the processing and disposal costs for reuse in an optimal inventory management environment. The authors employe Genetic Algorithm (GA), which is one of the optimization techniques, to verify the validity of the proposed model. And in order to investigate the effect of the parameters on the solution, the priority-based GA (priGA) under three different parameters and the modified Hybrid GA (mhGA), in which parameters are adjusted for each generation, were applied to four examples with varying sizes in the simulation.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.4A
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• pp.335-341
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• 2008

The SDR(Software Defined Radio) system for hardware and software must be an open structure to various system standards. It should also provide a capability of distributed processing, object-orientedness, and software controllability. It implies that the software to be used in the SDR system should provide the openness such that it can operate independently of a given hardware platform. In order to achieve these goals, the SDR system tends to modularization for increasing hardware reuse and design flexibility, which provides the system reconfigurability. In this paper, we implemented a base station with proposed an open architecture of a Smart Antenna Base Station(SABS) and Smart Antenna APIs[10] operating in SDR network in such a way that the architecture itself is suitable for the entire system to maintain the openness, object-orientedness, and software controllability.

• KIISE Transactions on Computing Practices
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• v.22 no.8
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• pp.357-362
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• 2016

A social network or bio network is one of the complex networks that are formed by connecting specific relationships between interacting objects. Usually, these networks consist of community structures. Automatically detecting the structures is an important technique to understand and control the interaction objects. However, the topologies and structures of the networks change by interactions of the objects, with respect to time. Conventional techniques for finding the community structure have a high computational complexity. Additionally, the methods inefficiently deal with repeated computation concerning graph operation. In this paper, we propose an incremental technique for detecting interaction-based communities in dynamic networks. The proposed technique is able to efficiently find the communities, since there is an awareness of changed objects from the previous network, and it can incrementally reuse the previous community structure.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.8 no.3
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• pp.778-798
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• 2014

This paper proposes a novel exposed-terminal-eliminated medium access control (ETE-MAC) protocol by combining channel reservation, collision avoidance and concurrent transmissions to improve multi-access performance of the multihop wireless networks. Based on the proposed slot scheduling scheme, each node senses the control channel (CCH) or the data channel (DCH) to accurately determine whether it can send or receive the corresponding packets without collisions. Slot reservation on the CCH can be simultaneously executed with data packet transmissions on the DCH. Therefore, it resolves the hidden-terminal type and the exposed-terminal type problems efficiently, and obtains more spatial reuse of channel resources. Concurrent packet transmissions without extra network overheads are maximized. An analytical model combining Markov model and M/G/1 queuing theory is proposed to analyze its performance. The performance comparison between analysis and simulation shows that the analytical model is highly accurate. Finally, simulation results show that, the proposed protocol obviously outperforms the link-directionality-based dual-channel MAC protocol (DCP) and WiFlex in terms of the network throughput and the average packet delay.

• Proceedings of the IEEK Conference
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• 2002.07a
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• pp.549-551
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• 2002

A Wireless Local Area Network (WLAN) is a flexible data communication system implemented as an extension to, or as an alternative for, a wired LAN with in a building or campus. However, communications in an indoor environment present problems not encountered in outdoor wireless communication systems. Since cellular type systems are interference limited, the indoor environment is more hostile than the outdoor environment due to the lower propagation constant. In this paper, the equation for the signal to interference ratio in a multistory building will be derived. Knowing the S/I ratio, the floor frequency reuse can be determined. Finally, the simulation in this research is designed to study the performance (BER) of WLAN system in the multistory environment by applying the 8-PSK Trellis Coded modulation technique. The procedure allows a quick evaluation of BER in Wireless LAN system due to the co-channel interference.

• Journal of Computing Science and Engineering
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• v.9 no.2
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• pp.83-97
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• 2015

IEEE 802.15.4 is a global standard designed for emerging applications in low-rate wireless personal area networks (LR-WPANs). The standard provides beneficial features, such as a beacon-enabled mode and guaranteed time slots for realtime data delivery. However, how to optimally operate those features is still an open issue. For the optimal operation of the features, this paper proposes a holistic optimization method that jointly optimizes three cross-related problems: cluster-tree construction, nodes' power configuration, and duty-cycle scheduling. Our holistic optimization method provides a solution for those problems so that all the real-time packets can be delivered within their deadlines in the most energy-efficient way. Our simulation study shows that compared to existing methods, our holistic optimization can guarantee the on-time delivery of all real-time packets while significantly saving energy, consequently, significantly increasing the lifetime of the network. Furthermore, we show that our holistic optimization can be extended to take advantage of the spatial reuse of a radio frequency resource among long distance nodes and, hence, significantly increase the entire network capacity.

• The KIPS Transactions:PartD
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• v.11D no.7 s.96
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• pp.1443-1450
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• 2004

The clustering characteristics for a number of classes, and defining the inheritance relations between the classes is a difficult and complex problem in an early stage of object oriented software development. We discuss a traditional iterative approach for the reuse of the existing classes in a library and an integrated approach to creating a number of new classes presented in this study. This paper formulates a character-istic clustering problem for zero-one integer programming and presents a network solution method with illustrative examples and the basic rules to define the inheritance relations between the classes. The network solution method for a characteristic clustering problem is based on a distance parameter between every pair of objects with characteristics. We apply the approach to a real problem taken from industry.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.42 no.9 s.339
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• pp.41-50
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• 2005

As the size of circuits becomes larger, the test method needs more test data volume and larger test application time. In order to reduce test data volume and test application time, a new test data compression/decompression method is proposed. The proposed method is based on an XOR network uses don't-care-bits to improve compression ratio during seed vectors generation. After seed vectors are produced seed vectors can be merged using two prefix codes. It only requires 1 clock time for reusing merged seed vectors, so test application time can be reduced tremendously. Experimental results on large ISCAS '89 benchmark circuits prove the efficiency of the proposed method.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.1
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• pp.364-369
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• 2012

Location information is a critical element of ubiquitous computing. Cricket is an indoor location-based system that transmits radio and ultrasonic signals in regular intervals to calculate the distance between nodes. However, the amount of signal interference and collisions increases in proportion with the number of nodes, losing the accuracy of the location-based system. This study proposes an algorithm based on the 802.15.2 MAC protocol for the wireless sensor network to reduce signal interference and collision by employing node numbers and the frequency reuse approach used in mobile telecommunication. We analyzed the performance of our algorithm. The obtained results showed that the algorithm is an effective for throughput and energy compared to the Cricket system.