• 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.

• 한국경영정보학회:학술대회논문집
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• 2008.06a
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• pp.1-6
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• 2008

Organizations are increasingly adopting Knowledge Management Systems (KMS) to effectively manage knowledge within the organization and realize firm and operational level benefits. However, many KMS implementations fail to yield desired outcomes due to the lack of understanding of the antecedent of successful knowledge management. Prior studies have established that organizational cultural values are one of the key enablers of knowledge management. We develop a computational model of organizational knowledge processes and employ simulations to examine the impact of KMS in different organizational cultural settings. We find that cultural values that govern the employees' predisposition towards seeking knowledge from others have a greater influence on KMS effectiveness than those that govern the employees' attitudes towards sharing their knowledge with others. We also find that organizations with cultures that foster high levels knowledge sharing behaviors can expect performance gains if KMS implementations incorporate knowledge seeking activities into the employees' work processes.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2001.12a
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• pp.229-232
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• 2001

Recently, several promising multiobjective evolutionary algorithms, e,g, SPEA, NSGA-ll, PESA, and SPEA2, have been developed. In this paper, we also propose a new multiobjective evolutionary algorithm that compares to them. In the algorithm proposed in this paper, we introduce a novel concept, "inherited age" and total algorithm is executed based on the inherited age concept. Also, we propose a new sharing algorithm, called objective classication sharing algorithm(OCSA) that can preserve the diversity of the population. We will show the superior performance of the proposed algorithm by comparing the proposed algorithm with other promising algorithms for the test functions.

• Proceedings of the KIEE Conference
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• 2003.04a
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• pp.208-211
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• 2003

This paper presents an improved droop method of the high voltage DC power supply which minimizes the voltage droop of a parallel-connected power supply. Conventionally, the droop method has been used to achieve a simple structure and no-interconnections among the power sources. However, it has a trade-off between output voltage regulation and load sharing accuracy. In this paper, the droop is minimized with a current and droop gain control using steady-stage estimation. The proposed method can achieve both high performance voltage regulation and load sharing. Two 10kV, 100mA parallel power modules were made and tested to verify the proposed current-sharing method.

• Journal of information and communication convergence engineering
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• v.6 no.3
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• pp.327-330
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• 2008

It is required that a server which communicates with various client simultaneously should have an efficient data transfer model. In Windows$^{(R)}$ environment, the server was generally developed based on IOCP model. Developing the IOCP model, the server generally has one data transfer buffer per client. If the server divides a larger data than the transfer buffer into several fragments, there used to be a problem in sending it to a client, because there is a conflict in a data transfer buffer. That is, CPU requests one data-fragment transfer, then it will request the next data-fragment transfer successively before completing the previous request, owing to the property of overlapped IO model. In this paper, we proposed the transfer buffer sharing technique to solve the conflicting problem. The experimental result shows that the performance of data transfer was enhanced by 39% maximally.

• IEMEK Journal of Embedded Systems and Applications
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• v.11 no.5
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• pp.259-265
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• 2016

In this paper, we present an architecture for the fault isolation by applying virtualization-based multi-stack technologies. We propose the simultaneous sharing and switching mechanism using virtualied serial communications. Each guest OS has its own virtual serial device. The distribution module provides communications between the guest OS's through the virtual serial devices and simultaneously detect the liveness of the guest OS. The suggested mechanism has been implemented in VirtualBox and shows satisfactory performance in transmission speed and data sharing capability with virtual RS232.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.26 no.12B
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• pp.1686-1694
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• 2001

In this paper, we analyze capacities of spectrum sharing scheme for both reverse link and forward link in hierachical CDMA cellular systems with Hot-spot microcell. Capacity analysis is performed through Monte-Carlo simulation by considering microcell radius, location of microcell. and transmission power ratio of microoell to macrocell. From simulation results, we analyzed these effects and derived a general design approach. In addition, the performance of spectrum sharing scheme for each link is analyzed in the capacity plane.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.8 no.11
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• pp.3731-3750
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• 2014

This paper considers a wideband cognitive radio network (WCRN) which can simultaneously sense multiple narrowband channels and thus aggregate the detected available channels for transmission and studies the ergodic throughput of the WCRN that operated under: the wideband sensing-based spectrum sharing (WSSS) scheme and the wideband opportunistic spectrum access (WOSA) scheme. In our analysis, besides the average interference power constraint at PU, the average transmit power constraint of SU is also considered for the two schemes and a novel cognitive radio sensing frame that allows data transmission and spectrum sensing at the same time is utilized, and then the maximization throughput problem is solved by developing a gradient projection method. Finally, numerical simulations are presented to verify the performance of the two proposed schemes.

• Journal of the Korean Institute of Intelligent Systems
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• v.11 no.8
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• pp.689-694
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• 2001

Recently, several promising multiobjective evolutionary algorithm such as SPEA. NSGA-II, PESA, and SPEA2 have been developed. In this paper, we also propose a new multiobjective evolutionary algorithm that compares to them. In the algorithm proposed in this paper, we introduce a novel concept, “inherited age” and total algorithm is executed based on the inherited age concept. Also, we propose a new sharing algorithm, called objective classication sharing algorithm(OCSA) that can preserve the diversity of the population. We will show the superior performance of the proposed algorithm by comparing the proposed algorithm with other promising algorithms for the test functions.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.4C
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• pp.454-460
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• 2004

In this paper, we studied hierarchical channel coding scheme using unequal error protection method for 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.