• Journal of the Korean Vacuum Society
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• v.7 no.3
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• pp.176-186
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• 1998

Pure Pt, Co and their alloy thin films with three different compositions (Pt66-Co34, Pt40-Co60 and Pt18-Co82) were deposited on Si(100) wafers and proposed as a set of certified reference materials (CRM) for the quantification and standardization of surface compositional analysis. The compositions of the binary alloy thin films were controlled by in-situ XPS analyses and the certified compositions of the films have been determined by ICP-AES and RBS analyses after thin film growth. Through comparison of the compositions determined by in-situ XPS with those by ICP, relatively accurate compositions could be obtained with a matrix effect correction. Standard deviations of XPS and AES round robin tests with the Pt-Co alloy thin films were large up to about 4%. On the other hand, the average compositions of the Pt-Co alloy thin films by two methods were in a good agreement within 1%. The formation of a Pt rich surface layer by ion beam sputtering indicates that the surface modification by preferential sputtering must be understood for a better compositional analysis.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.9
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• pp.2078-2082
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• 2010

The general bus system architecture consists of masters, slaves, arbiter, decoder and so on in shared bus. As several masters can't use a bus concurrently, arbiter plays an role in bus arbitration. In compliance with the selection of arbitration method, The efficiency of bus usage can be determined. Fixed Priority, Round-Robin, TDMA, Lottery arbitration are studied in conventional arbitration method. Conventional arbitration method is considered bus priority primarily, actual bus utilization didn't considered. In this paper, we propose arbitration method using bus utilization operating block of each master, we verify the performance compared with the other arbitration methods through throughput performance. From the result of performance verification, we confirm that proposed arbitration method, matched bus utilization set by the user 40%, 20%, 20%, 20%.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.16 no.8
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• pp.1613-1618
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• 2012

For network is growing at a rapid rate, network environment is more complex. The technology of using network traffic to monitor our network in real-time is developed. Cacti is a representative monitoring tool which based on RRDTool(Round Robin Database tool), SNMP(Simple Network Management Protocol). In this paper, it show you how to develop a system which based on Cacti and Libpcap to monitor our monitored objects. At this system, using Libpcap to capture network traffic packets, analyze these packets and then turn out in Cacti in graphical form. So as to achieve monitoring system. This system's execution is efficient and the management is easy and the results are accurate, so it can be widely utilized in the future.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.7A
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• pp.611-619
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• 2005

The present paper proposes two different packet scheduling algorithms in the IEEE 802.16e type TDD-OFDMA downlink, which are the weighted fair scheduling(WFS) and the throughput guarantee scheduling(TGS). The performance of proposed scheduling algorithms are compared to some of conventional schedulers such as round robin(RR), proportional fair(PF), fast fair throughput(FFTH), and fair throughput(FH) in terms of service coverage, effective throughput and fairness at 64 kbps and 128 kbps minimum user throughput requirements. For a relatively smaller throughput(64 kbps) requirement, the proposed algorithms provide higher improvement in the number of users per sector within 95$\%$ service coverage while satisfying the lxEV-DV fairness criterion. For a relatively larger throughput(128 kbps) requirement, the proposed algorithms provide higher coverage enhancement while maintaining the same effective aggregate throughput over PF scheduler.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.10A
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• pp.896-905
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• 2005

In this paper, we propose a SPD(Selective Packet Delay) scheme to improve the performance of High-Speed Downlink Shared Channel(HS-DSCH) employing N-Channel Stop and Wait retransmission scheme in High Speed Downlink Packet Access(HSDPA) system. The proposed SPD coordinates packet transmissions according to the channel condition. When the channel condition is bad, packet transmission is forcedly delayed, and the designated time slot is set over to other users in good channel condition. Hence, the SPD is able to reduce the average transmission delay for packet transmission under the burst error environments. In addition, we propose two packet scheduling schemes called SPD-LDPF(Long Delayed Packet First) and SPD-DCRR(Deficit Compensated Round Robin) that are effectively combined with the SPD scheme. Simulation results show that the proposed scheme has better performance in terms of delay, throughput and fairness.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.22 no.10
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• pp.2191-2204
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• 1997

An efficient packet transmit scheduling algorithm should be able to allocate the resource to each connection fairly based on the bandwidth and quality of service requirements negotiated during the call admission procedure and it should be able to isolate the effects of users that are behaving badly. In this paper, we propose an effective round-robin packet transmit scheduling mechanism, which we call the delay tolerant packet reserving scheme (DTPRS) based on delay QoS requirments. The proposed scheme can not only provide fairness and but also reduce delay, delay variation, and packet loss rate by reserving output link time slots of delay tolerant packets and assigning the reserved slotsto delay urgent packets. Our scheme is applicable to high speed networks including ATM network because it only requires O(1) work to process a packet, and is simple enough to implement.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.46 no.2
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• pp.38-44
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• 2009

Bus system consists of several masters, slaves, arbiter and decoder in a bus. Master means the processor that performs data command like CPU, DMA, DSP and slave means the memory that responds the data command like SRAM, SDRAM and register. Furthermore, as multiple masters can't use a bus concurrently, arbiter plays an role in bus arbitration. In compliance with the selection of arbitration method bus system performance can be charged definitely. Fixed priority and round-robin are used in general arbitration method and TDMA and Lottery bus methods are proposed currently as the improved arbitration schemes. In this stuff, we proposed the score arbitration method and composed TLM algorithm. Also we analyze the performance compared with general arbitration methods through simulation. In the future, bus arbitration policy will be developed with the basis of the score arbitration method and improve the performance of bus system.

• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.3
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• pp.22-33
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• 2014

As a standard of WMNs, IEEE 802.11s supports two kinds of MAC algorithm: a mandatory EDCA used by IEEE 802.11e and an optional MCCA. While EDCA classifies traffic according to four Access Categories (AC) and offer differentiated service using a classified priority, MCCA can guarantee the specific bandwidth of users with a TDMA-style bandwidth reservation scheme between mesh routers. In case that a flow is VBR traffic of a multimedia application, MCCA has disadvantage that the reserved bandwidth does not be used entirely, though it guarantees required bandwidth of users and fairness using bandwidth reservation with neighbors' node. In this paper, we showed a problem that is wastes the reserved bandwidth when MCCA is enabled and proposed a new scheduling algorithm to prevent waste of bandwidth and to improve network utilization effectively, named Resource Sharing Round Robin (RSRR) scheduling. Finally we showed simulation results that performance of a proposed RSRR is better than the legacy MCCA through NS-2 simulation.

• Journal of Mechanical Science and Technology
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• v.19 no.2
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• pp.634-648
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• 2005

Performed here is a comparative assessment study for the probabilistic fracture mechanics approach of the pressurized thermal shock of the reactor pressure vessel. A round robin consisting of one prerequisite deterministic study and five cases for probabilistic approaches is proposed, and all organizations interested are invited. The problems are solved by the participants and their results are compared to issue some recommendation of best practices and to assure an understanding of the key parameters in this type of approach, like transient description and frequency, material properties, defect type and distribution, fracture mechanics methodology etc., which will be useful in the justification through a probabilistic approach for the case of a plant over-passing the screening criteria. Six participants from 3 organizations responded to the problem and their results are compiled and analyzed in this study.

• Proceedings of the IEEK Conference
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• 2003.07a
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• pp.57-60
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• 2003

IEEE 802.16 Wireless MAN standard specifies the air interface of fixed point-to-multipoint broadband wireless access systems providing multiple service. Among the service classes supported by the wireless MAN, the BE class is ranked on the lowest position in priority and is usually deployed by multicast and broadcast polling MAC scheme. In provisioning such BE service, the delay performance is influenced by a number of components including restrictions on resource request per SS, the number of request opportunities in upward frame, scheduling requests at BS, and contention resolution method. As candidate components of MAC function for BE service, we propose single and multiple request schemes (for controling the number of requests per SS), exhaustive and limited request schemes (for regulating the amount of grant per request) and FCFS, H-SMF, pure SMF, SS-wise Round Robin, and pure Round Robin (for scheduling requests at BS). Then, we construct MAC schemes by combining the above components and evaluate the delay performance exhibited by each MAC scheme using a simulation method. From numerical results, we investigate the effect of MAC components on average delay and delay variation and observe the dissonance on collision reduction in a resource - limited environment.