• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.4B
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• pp.659-669
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• 2010

The P2P IPTV will create a new paradigm for the Internet services. However, it cannot guarantee the reliability of their server and QoS because of using common Internet users(peers) for SIP server or relay server, though the infrastructural cost is low. This paper proposes the ISP-based P2P IPTV architecture which can solute the limitations of conventional P2P-based IPTV. In this model, ISP can build P2P overlay network with ISP servers and directly manage each server needed for session connection. So, the servers have higher performance and better reliability than previous one. Besides, robustness is improved because each sever is set by P2P overlay network. To evaluate the characteristics of the ISP-based P2P IPTV architecture, we simulate it for some parameters which are end-to-end streaming delay time, connection delay time and traffic amount. We compared the proposed architecture with the conventional P2P architecture about video service and confirmed that the performance of ISP-based P2P IPTV is better than conventional P2P based IPTV.

• Journal of Animal Science and Technology
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• v.51 no.5
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• pp.427-432
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• 2009

This study was undertaken to screen a high xylanase and mannanase producing microbes. In the first experiment, screening was undertaken against 50 samples of microorganisms having xylanase and mannanase activities from soil and fallen leaves. The screening process has focused on picking out fungi having high xylanase and mannanase activities under the solid-state fermentation. The xylanase and mannanase activities of 6 screened microbes were 0.9~1.6 unit/mL and 0.2~0.4 unit/mL, respectively, under the submerged fermentation condition. However, under the solid-state fermentation, xylanase and mannanase activities were 103.7~220.0 unit/g and 20.1~40.3 unit/g, respectively. Finally one microbe (E-3) was selected and its xylanase and mannanase activities were 197.3 unit/g and 39.9 unit/g, respectively. The morphological and molecular biological classification of E-3 showed 99% homology with the Aspergillus niger.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.29 no.11 s.242
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• pp.1265-1276
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• 2005

The elliptic conceptual second moment models for turbulent heat fluxes, which are proposed on the basis of elliptic-blending and elliptic-relaxation equations, are applied to calculate the combined forced and natural turbulent convection in a vertical plane channel. The models satisfy the near-wall balance between viscous diffusion, viscous dissipation and temperature-pressure gradient correlation, and also have the characteristics of approaching its respective conventional high Reynolds number model far away from the wall. Also the models are closely linked to the elliptic blending model which is used for the prediction of Reynolds stress. In order to calibrate the heat flux models, firstly, the distributions of mean temperature and scala flux in fully developed channel flow with constant wall difference temperature are solved by the present models. The buoyancy effect on the turbulent characteristics including the mean velocity and temperature, the Reynolds stress tensor, and the turbulent heat flux vector are examined. In the opposing flow, the turbulent transport is greatly enhanced with both the Reynolds stresses and the turbulent heat fluxes being remarkably increased; whereas, in the aiding flow, the opposite change is observed. The results of prediction are directly compared to the DNS to assess the performance of the model predictions and show that the behaviors of the turbulent heat transfer in the whole flow region are well captured by the present models.

• Journal of the Korean Society of Marine Environment & Safety
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• v.10 no.1 s.20
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• pp.1-7
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• 2004

RADARSAT is one of many possible data sources that can play an important role in marine surveillance including ship detection because radar sensors have the two primary advantages: all-weather and day or night imaging. However, atmospheric effects on SAR imaging can not be bypassed and any remote sensing image has various geometric distortions, In this study, radiometric and geometric calibrations for RADARSAT/SAT data are tried using SGX products georeferenced as level 1. Even comparison of the near vs. far range sections of the same images requires such calibration Radiometric calibration is performed by compensating for effects of local illuminated area and incidence angle on the local backscatter, Conversion method of the pixel DNs to beta nought and sigma nought is also investigated. Finally, automatic geometric calibration based on the 4 pixels from the header file is compared to a marine chart. The errors for latitude and longitude directions are 300m and 260m, respectively. It can be concluded that the error extent is acceptable for an application to open sea and can be calibrated using a ground control point.

• Food Science and Preservation
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• v.8 no.4
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• pp.434-441
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• 2001

The purpose of this research is the establishment of optimal processing and the quality improvement of confectionary analysis of the damaged starch content of flour. I studied the rheological and bread making properties of the dough containing different damaged starch content. I examined rheological and physico- chemical characteristic farinograph, extensograph and amylograph with DNS, CWRS and SW containing 6.5%, 8.2%, 9.0%, 9.0% and 10.5% of damaged starch. And I measured the hardness and specific volume and performed the functional survey by rheometer for quality control. In the amylogram, at the damaged starch content 9.5% at such the maximum viscosity was 900 B.U. the volume of bread fermention tolerance were increased. In addition, the extensegram after 135 min showed that maximum resistance of the dough were 570 B.U at the damaged starch contents of 9.5% and the bread had homogeneous air cells and internal structures at the damaged starch contents of 9.5% at which the area(A), resistance(R) and R/E value of the dough were highest.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2002.11a
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• pp.652-655
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• 2002

The next generation Internet Protocol IPv6 that is appeared to solve the exhausting problem is now widely deployed in a testbed or commercial site. To successfully deploy IPv6, interoperation with exist IPv4 hosts and routers and interactions with many IPv4 applications are more important. The NAT-PT (Network Address Translation-Protocol Translation) among IPv6 transition mechanism enables the communication between IPv4 and IPv6 host with translating IPv4 address and IPv6 address. But for DNS and FTP, another specific mechanism is needed when internet address is included in packet payload area. This paper describes the design and implementation of IPv6-support FTP-ALG, (Application Layer Gateway) to enable FTP service between IPv4 node and IPv6 node.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2016.05a
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• pp.317-320
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• 2016

The NH-NongHyup network and servers were paralyzed in 2011, in the 2013 3.20 cyber attack happened and Classified documents of Korea Hydro & Nuclear Power Co. Ltd were leaked on December in 2015. All of them were conducted by a foreign country. These attacks were planned for a long time compared to the script kids attacks and the techniques used were very complex and sophisticated. However, no successful solution has been implemented to defend an APT attack thus far. Therefore, we will use big data analytics to analyze whether or not APT attack has occurred in order to defend against the manipulative attackers. This research is based on the data collected through ISAC monitoring among 3 hierarchical Korean defense system. First, we will introduce related research about big data analytics and machine learning. Then, we design two big data analytics models to detect an APT attack and evaluate the models' accuracy and other results. Lastly, we will present an effective response method to address a detected APT attack.

• KSBB Journal
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• v.28 no.1
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• pp.42-47
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• 2013

This study was performed to find cellulolytic strain of enzymatic saccharification for bioethanol production. Cellulolytic strains were isolated from 59 different feces of herbivores from Seoul Grand Park located in Gwacheon Gyeonggi-Do. The celluloytic strain was selected by congo red staining and DNS method. Among the isolated strains, H9-1 strain isolated from the feces of rabbit has the highest CMCase activity. H9-1 strain was identified as Bacillus sp. based on 16S rDNA gene sequencing. The optimal conditions for CMCase activity by Bacillus sp. H9-1 were at $40^{\circ}C$ and at initial pH 8.

• Proceedings of the KSME Conference
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• 2008.11b
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• pp.2465-2470
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• 2008

A new surface shape of an internal cooling passage which largely reduces the pressure drop and enhances the surface heat transfer is proposed in the present study. The surface shape of the cooling passage is consisted of the concave dimple and the riblet inside the dimple which is protruded along the stream-wise direction. Direct Numerical Simulation (DNS) for the fully developed turbulent flow and thermal fields in the cooling passage is conducted. The Numerical simulations for the 5 different surface shapes are conducted at the Reynolds number of 2800 based on the mean bulk velocity and channel height and Prandtl number of 0.71. The driving pressure gradient is adjusted to keep a constant mass flow rate in the x direction. The thermo-aerodynamic performance for the 5 different cases used in the present study was assessed in terms of the drag, Nusselt number, Fanning friction factor, Volume and Area goodness factor in the cooling passage. The value of maximum ratio of drag reduction is -22.86 [%], and the value of maximum ratio of Nusselt number augmentation is 7.05 [%] when the riblet angle is $60^{\circ}$ (Case5). The remarkable point is that the ratio of Nusselt number augmentation has the positive value for the surface shapes which have over $45^{\circ}$ of the riblet angle. The maximum Volume and Area goodness factor are obtained when the riblet angle is $60^{\circ}$ (Case5).

• Journal of the Korean Institute of Landscape Architecture
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• v.23 no.1
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• pp.111-122
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• 1995

12 populatiDns of Ch indicum L. and it's variation antogenous in Tforea were selected throughout the country and their morphological characteristics were studied in this paper. The results are as follows. 1) The mean of the plant height is 97.3cm. Ch. indicunl is 76.5cm and Ch. boreale is 116. 6cm in height. The number of nodes is 58 on the average. The color of the stem is generally black-red in the case of Ch. indicum and is green for Ch. boreale. 2) The leaves of Ch. inficum are smaller In size and thicker than chose of Ch. boreale, and it has a stipule. This fact enables us to distinguish one species from the other, however, the Gyukpo-population of Ch. indicum has a large leaf, and Byunsan-population of Ch. boreale has a stipule so that the above fact is not an exact criterion on which to base one classification. 3) The size of the capitulum is 24.9mm for Ch. indicum and 15.6mm in the case of Ch. boreaje so that the difference between species is admitted. It was confirmed hat the size of the capitulum has positive correlation to that of the pedicel and has egative correlation to the number of flowers, so that of inflorescence, Ch. indicumhas corymb, and Ch. boreale has crowed corymb or umbel-type.The number of ligulates is 19 on the average, which no the difference being founnd between species and populations.4) The cluster analysis of morphological characteristics showed that Ch. indicum wasdivided into two groups, which was shown thought to be due to the difference of speciesbetween Ch. indicum and Ch. boreale. However, it could not be shown that their morphological characteristics explain a geographical relationship between populations