• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.7
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• pp.1621-1630
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• 2009

There is a lot of recent research to provide services of dynamic distributed contents in P2P-based distributed environment. Distributed services of contents objects, however, have problems in QoS and dynamic management of segments. This paper proposed a new segment management method for the service of P2P-based distributed contents. The proposed method manages groups by the SGM(Segment Group Manager). The SGM manages streaming efficiently by the grouping of segments to be served in P2P environment. The segments in the same group cooperate for improved QoS using the management structure based on the distance and relationship. The distance-based management structure is for the improvement of retrieval efficiency while the relationship-based management structure is for the improvement of service ratio. The simulation results of the proposed method showed improvements in average transmission efficiency and average service rate. The improvement is 8% - 30% in average transmission efficiency and 10% - 30% in average service rate.

• Polymer(Korea)
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• v.32 no.6
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• pp.549-554
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• 2008

In order to synthesize polymer particle containing inorganic material, styrene and n-butylmethacrylate were copolymerized with alumina by dispersion polymerization. The weight ratio of styrene to n-butylmethacrylate was 3 : 1. A poly(N-vinyl pyrrolidon) was added as stabilizer. 2,2'-AzobisCisobutyronitrile) and 3-methacryloxypropyl trimethoxysilane were used as initiator and coupling agent, respectively. The weight ratio of 70 : 30 of isopropanol to distilled water was used as dispersion medium. According to the TEM measurement, we could confirm that alumina was dispersed into the polymer particle. The increase 'of concentration of alumina resulted in enhancement of particle size, but decreased its distribution. By the XRD method, it was found that the increase of alumina concentration showed the increase of intensity in peak and the increased 2$\theta$ value. From the TGA measurement, the increase of alumina concentration caused high heat resistance of the polymer. With respect to the type of initiator, the longer half life of initiator, the smaller particle size. We also found that the increase of particle stabilizer concentration made the decreased of particle size due to the accelerated generation of polymer particle in the early stage of reaction.

• Journal of Broadcast Engineering
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• v.19 no.2
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• pp.257-267
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• 2014

Distributed compressive video sensing (DCVS) is a low cost sampling paradigm for video coding based on the compressive sensing and the distributed video coding. In this paper, we propose using a skip-mode coding in DCVS under the assumption that in case of high temporal correlation, temporal interpolation can guarantee sufficiently good quality of nonkey frame, therefore no need to transmit measurement data in such a nonkey frame. Furthermore, we extend it to use a hierarchical structure for better temporal interpolation. Simulation results show that the proposed skip-mode coding can save the average subrate of whole video sequence while the PSNR is reduced only slightly. In addition, by using the proposed scheme, the computational complexity is also highly decreased at decoder on average by 43.75% for video sequences that have strong temporal correlation.

• Polymer(Korea)
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• v.27 no.4
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• pp.377-384
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• 2003

High impact polystyrene/organically modified layered silicate (HIPS/OLS) nanocomposites by in situ polymerization were synthesized to investigate the effect of clay on the particle size and properties of rubber. In the OLS, the montmorillonite having benzyl group showed best dispersion in polystyrene phase. With the addition of clay, the intercalated peak from XRB was confirmed, but the peak gradually shifted to lower angle as rubber concentration increased. Thus, it is speculated that the organoclay disperses better in rubber phase than in polystyrene phase. The average rubber particle size increased and the particle size distribution widened as the amount of clay increased, which may be caused by the increase of the viscosity ratio of rubber to polystyrene phases and the unstable dispersion. The materials having clay showed improved thermal properties from thermogravimetric analysis. Rheological properties such as complex viscosity and storage modulus increased as the amount of clay increased.

• Journal of the Korean Data and Information Science Society
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• v.21 no.6
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• pp.999-1008
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• 2010

The objective of this paper is to develop variable sampling interval multivariate control charts that can offer significant performance improvements compared to standard fixed sampling rate multivariate control charts. Most research on multivariate control charts has concentrated on the problem of monitoring the process mean, but here we consider the problem of simultaneously monitoring both the mean and variability of the process.

• Journal of Advanced Navigation Technology
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• v.15 no.4
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• pp.562-570
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• 2011

In this paper, a distributed mobile relay power control (DMRPC) scheme for maximizing individual cell throughput is proposed for mobile relay aided multi-cell orthogonal frequency division multiplexing (OFDM)-time division duplex (TDD) system. In the system with DMRPC, the power levels of relay's are controlled by individual cell without cell cooperation and signalling overhead. It is demonstrated by numerical simulation that DMRPC provides the better cell throughput performance than either the full power relay aided system or conventional system without relay does. Moreover, it is also shown that relay aided systems with DMRPC, and the conventional system have almost identical cell edge throughput, while full power relay aided systems show worse performance in cell edge throughput.

• 한국해양학회지
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• v.24 no.1
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• pp.1-14
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• 1989

This study analyzes the interannual periodicity by using the statistical techniques of probability, spectral analysis, empirical orthogonal function analysis (EOF), and coherency analysis. The data base for this study is the time series of 1971-1985 temperature, salinity in the southern waters of the East Sea, 1960-1986 mean sea level at Pusan and Izuhara, and 1960-1986 sea level atmospheric pressure at Pusan. The appearances of anomalous temperatures higher and lower than 15-year mean monthly average with one standard deviation are about 30% of total data. The significant interannual period for temperature, salinity and sea level fluctuation is 36.6, and 23.3 months. The empirical orthogonal function analyses show that the 1st mode of the EOFs is responsible for more than 90% of total variance of the surface temperature variations, while in near-bottom waters, the relative importance of the higher EOF modes is much greater explaining more than 30% of total variance. The coherency between normalized temperatures and salinities is significant at the interannual period of 36.6 and 21.3 months.

• The Journal of the Korea Contents Association
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• v.14 no.4
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• pp.227-236
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• 2014

This study was conducted to explore the mediation effects of irrational belief on the relationship between game addiction and anger behavior. For this study, 431 middle school boys in Chungcheong areas were included in the analysis. The results showed that game addiction was positively correlated with direct anger-out, rumination, diffusion as well as irrational belief. The boys at high risk of game addiction showed higher mean scores on irrational belief, direct anger-out, rumination: and diffusion than other students. Irrational belief (mediator) partially mediated the influence of the boys' game addiction (independent variable) on direct anger-out, rumination, and diffusion (dependent variable). Finally, limitations of this study and suggestions for future study were discussed.

• Journal of the Korea Society of Computer and Information
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• v.10 no.6 s.38
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• pp.37-46
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• 2005

In Processing many operations based on distributed environment, it is very important to support the reliability of resources. Providers of resources generally adapt the structure of server-replication to support the reliability of services. Tn server side, it maintains replicas. duplicated server objects. In the structure of this replication, service of stable replica is very important. Therefore the structure to diagnosis the fault of such replica is required. In this Paper, we suggested an effective PUSH fault management algorithm based on PUSH monitoring style of CORBAto overcome weak points of the PULL monitoring style of the replication management system in the distributed object system. Outcomes of the suggested PUSH fault monitoring style were better than other system. We confirmed valuable result in the workloads and timeout-rates.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.04a
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• pp.20-23
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• 2011

The spray and atomization characteristics of swirl coaxial injectors which use gas methane and LOx as propellants are investigated experimentally with a recess length variation. Mass distribution and spray angle are measured by a patternator and droplet size to find atomization characteristics are measured by GSV(Global Size and Velocity) system. As a result, when the liquid sprayed, the spray angle decreased and the atomization characteristic was improved with the recess length increase. When the gas and liquid injected simultaneously, the spray angle was decreased and the atomization characteristic was improved comparing to only the liquid injection.