• Journal of Korea Multimedia Society
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• v.7 no.4
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• pp.550-558
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• 2004

Previous researches on scalability problem of distributed virtual environment (DVE) have been mainly focused on spatial partitioning of area of interest (AOI). Congestion phenomena by avatar groups in AOI have been neglected relatively However, AOI congestion is highly related to scalability of DVE because it exhausts system resources such as network bandwidth and rendering time, and could be a bar to perform collaboration among participants. In this paper, this will be defined as the problem that must be solved for the realization of the scalable DVE, and a model will be proposed to measure and control congestion situation in AOI. The purposes of the proposed model are to prevent high density of participants in AOI, and to protect stable collaboration in DVE. For evaluation of the performance it is compared with a previous method by defining the resource cost model which is dynamically activated to AOI congestion.

• Journal of KIISE:Information Networking
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• v.28 no.4
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• pp.559-569
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• 2001

With the growth of the Internet, applications using the reliable multicast protocol are increasing. Two important requirements of reliable multicasting are reliability and scalability. To enhance scalability, many methods have been proposed. A typical method is a local recovery scheme. This paper proposes a new stable and effective protocol with the following features. The first is to apply the discipline of the separations of concerns to NAK message. By dividing the functions of the NAK message into the error recovery request and the NAK-suppression, each function can be optimized. Second, a local representative, which is selected gradually and distributively, executes error recovery in somewhat deterministic manner. Finally, by dynamically adjusting the TTL value of the control message, the error recovery domain can be optimized. The proposed scheme has been implemented and experimented on Network Simulator. Compared to the existing schemes, the performance results show that scalability has not only been enhanced but also error recovery time and network overhead have been reduced.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2007.06a
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• pp.61-64
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• 2007

MPLS networks architectures have been prevailed as scalable approach to provide quality of service in the Internet. Many researches have been mainly focused on scalability and multi-path calculation scheme for failure restoration. However, the MPLS network have an scalability problem about traffic, and the existing failure restoration methods are wasted resources, and it has the problem that loss of a packet by a lot of delay occurs in too. Therefore in this paper, we propose a H-MPLS (Hierachical-Multiprotocol Label Switching)network for rapidly failure restorations and effective management of network extended. The proposed H-MPLS Network apply LSP multi-path routing algorithm and consists of several MPLS. After comparing the performance among the existing failure restoration methods with various network models, we use NS simulator in order to analyze the performance. Finally, we present an improvement scheme of the efficiency and scalability.

• Journal of Advanced Navigation Technology
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• v.20 no.1
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• pp.65-71
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• 2016

Quantum-dot cellular automata (QCA) consists of nano-scale cells and demands very low power consumption so that it is one of the alternative technologies that can overcome the limits of scaling CMOS technologies. Typical BCD-EXCESS 3 code converters using QCA have not considered the scalability so that the architectures are not suitable for a large scale circuit design. Thus, we design a BCD-EXCESS 3 code converter with scalability using QCADesigner and verify the effectiveness by simulation. Our structure have reduced 32 gates and 7% of garbage space rate compare with typical URG BCD-EXCESS 3 code converter. Also, 1 clock is only needed for circuit expansion of our structure though typical QCA BCD-EXCESS 3 code converter demands 7 clocks.

• KIISE Transactions on Computing Practices
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• v.20 no.11
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• pp.604-609
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• 2014

Decoding processes in portable media players have a high computational cost, resulting in high power consumption by the CPU. If decoding computations are reduced, the power consumed by the CPU is also be reduced, but such a choice generally results in a degradation of the video quality for the users, so it is essential to address this tradeoff. We proposed a new CPU power management scheme that can make use of the scalability property available in the H.164/SVC standard. We first proposed a new video quality model that makes use of a video quality metric(VQM) in order to efficiently take into account the different quantization factors in the SVC. We then propose a new dynamic voltage scaling(DVS) scheme that can selectively combine the previous decoding times and frame sizes in order to accurately predict the next decoding time. We then implemented a scheme on a commercial smartphone and performed a user test in order to examine how users react to the VQM difference. Real measurements show that the proposed scheme uses up to 34% fewer energy than the Linux DVFS governor, and user tests confirm that the degradation in the quality is quite tolerable.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.42 no.3 s.303
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• pp.31-40
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• 2005

In this paper, we develop an approach toward JSC(Joint Source-Channel Coding) method for MPEG-4 based FGS(Fine Granular Scalability) video coding and transmission in fixed and mobile receiving environment(Digital Audio Broadcasting, DAB). The source coder used MPEG-4 FGS video codec, the channel coder used RCPC(Rate Compatible Punctured Convolution) code and the modulation method used QPSK modulation. We have considered channel environment of AWGN and mobile receiving environment. This study determined optimum Trade-off point between source bit rate and channel coding rate in variable channel states. We compared FGS-JSC method and general single layer CBR(Constant Bit Rate) transmission. In this results, FGS-JSC was appeared better performance than CBR transmission.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.26 no.4
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• pp.275-281
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• 2013

In this paper, determination of the scalability of the cluster composed common personal computer was performed when optimization of reinforced concrete structure using genetic algorithm. The goal of this research is watching the potential of multi-core-PC cluster for optimization of seismic design of reinforced-concrete structures. By increasing the number of core-processer of cluster, decreasing of computation time per each generation of genetic algorithm was observed. After classifying the components in singular personal computer, the estimation of the expected bottle-neck phenomenon and comparison with wall-clock time and Amdahl's law equation was performed. So we could obseved the scalability of the cluster appear complex tendency. For separating the bottle-neck phenomenon of physical and algorithm, the different size of population was selected for genetic algorithm cases. When using 64 core-processor, the efficiency of cluster is low as 31.2% compared with Amdahl's law efficiency.

• The Transactions of the Korea Information Processing Society
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• v.7 no.8
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• pp.2370-2387
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• 2000

This paper proposes a new design strategy that can overcome limitations of two existing approaches, focusing on performance and scalability issues among various architectural issues which must be considered in designing workflow systems. In the proposed approach, we suggest to introduce 'delegation model' which corresponds to the high-level strategy utilizing the fundamental characteristics of mobile agents, after establishing a mobile agent-based workflow system architecture focused on performance and scalability. We point out three major issues that should be considered in this approach and propose a 3-tier mobile agent-based workflow system architecture that effectively reflects these considerations. Also, we show that the new approach can provide better performance and scalability than existing ones - approaches based on the client-server paradigm and other approaches based on mobile agent paradigm represented by DartFlow system - by evaluating performance of the proposed architecture through the GSPN simulation.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.12B
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• pp.1359-1370
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• 2009

In wireless sensor networks, data dissemination is based on data-centric routing that well matches the publish/subscribe communication paradigm. The publish/subscribe paradigm requires decoupling properties: space, time, and synchronization decoupling. For large-scale applications, the three decoupling properties provide scalability and robust communication. However, existing data dissemination schemes for wireless sensor networks do not achieve full decoupling. Therefore, we propose a novel data dissemination scheme that fully accomplishes the three decoupling, called ARBIETER. ARBITER constructs an independent network structure as a logical software bus. Information interworking between publishers and subscribers is indirectly and asynchronously performed via the network structure. ARBITER also manages storage and mapping of queries and data on the structure because of supporting different time connection of publishers and subscribers. Our simulation proves ARBITER show better performance in terms of scalability, network robustness, data responsibility, mobility support, and energy efficiency.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.42 no.5
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• pp.1-8
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• 2005

SPEC CPU2000 is an widely used benchmark program, both in industry and in academy, for measuring compute-intensive performance of computer systems with various architectures. However, there has been little effort to investigate its characteristics with respect to hardware components. This paper presents the performance scalability of SPEC CPU2000 benchmark over CPU clock speed. For an Intel x86-based system running at various clock speed, we measure the performance of SPEC CPU2000 benchmark, and analyze the characteristic of SPEC CPU2000 in a system aspect. In the experiment, we found that the overall performance of SPEC CPU2000 increases monotonically and linearly as the CPU clock speed increases and that the scale efficiencies of SPEC CPU2000 component benchmarks are quite evenly distributed.