• Journal of applied mathematics & informatics
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• v.2 no.2
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• pp.21-46
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• 1995

Congestion and memory occupancy in computer system may be reduced further if new jobs are admitted only when the num-ber of jobs queued at CPU is below CPU run queue cutoff (RQ). In this paper we prove that response time of a job is invariant with respect to RQ if jobs do not communicate each other. We also demonstrate this invariance property numerically using marix-geometric methods and present an approximate method for the delay due to context switch-ing under time slicing. The approximation suggests that time slicing with constant overhead yields a throughput similar to an FCFS system without overhead.

• Proceedings of the IEEK Conference
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• 2006.06a
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• pp.633-634
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• 2006

A new specification-based analog and mixed-signal test technique using high performance current sensors is proposed. The proposed technique using current sensors built in external ATE has little hardware overhead in circuit under test and high testability without time consuming operation of test point placement algorithm.

• Proceedings of the IEEK Conference
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• 2002.07a
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• pp.176-179
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• 2002

In recent years, an increasing amount of computer network research has focused on the problem of cluster system in order to achieve higher performance and lower cost. The load unbalance is the major defect that reduces performance of a cluster system that uses parallel program in a form of SPMD (Single Program Multiple Data). Also, the load unbalance is a problem of MPP (Massive Parallel Processors), and distributed system. The cluster system is a loosely-coupled distributed system, therefore, it has higher communication overhead than MPP. Dynamic load balancing can solve the load unbalance problem of cluster system and reduce its communication cost. The cluster systems considered in this paper consist of P heterogeneous nodes connected by a switch-based network. The master node can predict the average execution time of tasks for each slave node based on the information from the corresponding slave node. Then, the master node redistributes remaining tasks to each node considering the predicted execution time and the communication overhead for task migration. The proposed dynamic load balancing uses execution time prediction to optimize the task redistribution. The various performance factors such as node number, task number, and communication cost are considered to improve the performance of cluster system. From the simulation results, we verified the effectiveness of the proposed dynamic load balancing algorithm.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.7 no.2
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• pp.386-404
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• 2013

In broadband satellite multimedia (BSM) system, burst time plan (BTP) is always periodically generated. We find that this method can have a great effect on the system response ability to bandwidth requests. A general analysis model of BTP generation method is given. An optimized BTP generation (O-BTPG) method is presented by deducing the optimal bandwidth allocation period (BAP) and bandwidth allocation latency (BAL) without considering the signaling overhead caused by BTP. Then a novel asynchronous BTP generation (A-BTPG) method in which the BTP is generated asynchronously according to the traffic load from users' bandwidth requests is proposed. Simulation results show that A-BTPG can flexibly realize a trade-off between the system response ability and BTP signaling overhead. What's more, it can be widely used in various regenerative onboard switching BSM systems.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.12A
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• pp.1136-1146
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• 2005

In this paper, the radiative electric field intensity due to the communication signal and conductive noise is calculated in overhead medium voltage power lines for power line communication. The input impedance is calculated by means of 2 port equivalent model of medium voltage power line network and basic transmission line theory. And then, currents is calculated by calculated input impedance and finally, the emissive electric field is calculated. The input impedance appears like a standing wave form with a fixed cycle because high reflection at the input terminal due to the characteristic impedance of medium voltage power line is very large. A calculated current and radiative electric field also appears like this form. From the measurement results, the measured results are very similar to the calculated results.

• Journal of Korea Multimedia Society
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• v.18 no.12
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• pp.1547-1554
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• 2015

Because there are numerous near field communication (NFC) technical standards and each standard has an independent communication protocol, an NFC software for controlling the protocols are significantly complicated. Especially, the anticollision algorithm for establishing the initial communication connection is classified into bit-oriented or time slot method according to the technical standards. Moreover, the anticollision algorithm is generally manipulated in software because of its complexity. In addition, since one host processor is shared by multiple modems in a connectivity SoC, embedding several communication modems with an NFC modem, the spare computing resources can be utilized for other modems by reducing the software cost to control the NFC modem. In this paper, we propose new design methods of the NFC modem for supporting anticollision, framing and bit rate detection in the hardware to reduce the software overhead. Therefore, the utilization of the NFC technology is enhanced in the connectivity SoC by minimizing the cost of software.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.9 no.3
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• pp.658-663
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• 2008

In this study, we estimated the influence of electrical pole by FEM(Finite Element Method) and developed protective system by designing and interpreting protective system for electrical pole and overhead optical communication line when abnormal strength worked on messenger wire. Protective system did not shed messenger wire under wind pressure and discontent load but did assign a part to preventing rupture of electrical pole and disconnection of optical communication line through automatically shed messenger wire over fixed strength. Structure of protective system analysis by FEM and prove property by measuring tensile strength for practical product.

• The Journal of Society for e-Business Studies
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• v.24 no.2
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• pp.55-70
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• 2019

It is essential to consider the relationships between each component in the communication infrastructure in order to build and optimize the infrastructure. In this paper, based on the major factors to consider for the optimized communication infrastructure, we propose an enhanced MACSec-based deployment mechanism for communication infrastructure. The proposed MACSec mechanism can replace the IPSec without the additional devices and redesign of the communication infrastructure. In addition, we evaluate the performance of MACSec and IPSec in terms of the major factors such as message overhead, encryption processing, and host mobility. According to the evaluation results, we can say that MACSec is superior to IPSec with regard to mobility as well as hop delay and message overhead.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.46 no.3
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• pp.96-106
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• 2009

Extending the scale of the distributed processing in a single Ethernet cluster is physically restricted by maximum ports per switch. This paper presents an implementation of MPI-based multicluster consisting of multiple Ethernet switches for extending the scale of distributed processing, and a asymptotical analysis for communication overhead through execution-time analysis model. To determine an optimum task partitioning, we analyzed the processing time for various partitioning schemes, and AAP(accumulator array partitioning) scheme was finally chosen to minimize the overall communication overhead. The scope of data partitioned in AAP was modified to fit for incremented nodes, and suitable load balancing algorithm was implemented. We tried to alleviate the communication overhead through exploiting the pipelined broadcast and flat-tree based result gathering, and overlapping of the communication and the computation time. We used the linear pipeline broadcast to reduce the communication overhead in intercluster which is interconnected by a single link. Experimental results shows nearly linear speedup by the proposed parallel distributed GHT implemented on MPI-based Ethernet multicluster with four 100Mbps Ethernet switches and up to 128 nodes of Pentium PC.

• IEMEK Journal of Embedded Systems and Applications
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• v.3 no.4
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• pp.207-217
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• 2008

A novel scheme is presented for Traffic Encryption Key (TEK) rekeying with low communication overhead for an Internet Protocol television (IPTV) conditional access system over Data-Over-Cable Service Interface Specifications (DOCSIS) 3.0. The proposed scheme utilizes the DOCSIS system synchronization for periodic TEK rekeying instead of a conventional TEK rekeying negotiation process. Analysis shows that the communication overhead is only 0.012 Kbps when TEK rekeying frequency is 1 second.