• The Transactions of the Korea Information Processing Society
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• v.5 no.7
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• pp.1855-1862
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• 1998

An Internet user obtains an IP address from DNS to access the host. But, Korean users must use English word order Domain that is not convenient for them. All existing systems have the reverse of the Korean word order and that is the obstacle to the spreading of Internet. So, the necessity of a Korean name system that well suited for Korean Internet user is increasing. In order to operate the proposed Korean Domain System with existing Domain Name Systems, we build a Korean to English transformation rule and Korean Domain Name composition rule. Also, we designed a STHOP for Korean word order processing. In a STROP, a SLDF transform a Korean SLD into English SLD, and a NFDNG makes this as an English word order. By using Korean Domain Name System proposed here, users could understand the embedded meaning of Domain Name with ease, and reluctance of Domain registration caused by similarity of organization names would be solved, Consequently. it could devote to the popularization of the Internet.

• Journal of Ocean Engineering and Technology
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• v.19 no.6 s.67
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• pp.35-43
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• 2005

Recently, various-shaped coastal structures have been studied and developed. Among them, the submerged breakwater became generally known as a more effective structure than other structures, bemuse it not only serves its original function, but also has the ability to preserve the coastal environment. Most previous investigations have been focused on the wave deformation and energy dissipation due to submerged breakwater, but less interest was given to their internal properties and dynamic behavior of the seabed foundation under wave loadings. In this study, a direct numerical simulation (DNS) is newly proposed to study the dynamic interaction between a permeable submerged breakwater aver a sand seabed and nonlinear waves, including wave breaking. The accuracy of the model is checked by comparing the numerical solution with the existing experimental data related to wave $\cdot$ permeable submerged breakwater $\cdot$ seabed interaction, and showed fairly nice agreement between them. From the numerical results, based on the newly proposed numerical model, the properties of the wave-induced pore water pressure and the flow in the seabed foundation are studied. In relation to their internal properties, the stability oj the permeable submerged breakwater is discussed.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.36 no.8
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• pp.829-837
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• 2012

Direct numerical simulations were carried out for turbulent channel flows with $Re_{\tau}$ = 180, 395 and 590 to investigate the turbulent flow structure related to the Reynolds shear stress. By examining the probability density function, the second quadrant (Q2) events with the largest contribution to the mean Reynolds shear stress were identified. The change in the inclination angle of Q2 events varies with wall units in $y^+<50$ and with the channel half height in y/h > 0.5. Conditionally averaged flow fields for the Q2 event show that the flow structures associated with Reynolds shear stress are a quasi-streamwise vortex in the buffer layer and a hairpin-shaped vortex in the outer layer. Three-dimensional visualization of the distribution of high Reynolds shear stress reveals that the organization of hairpin vortices in the outer layer having a size of 1.5~3 h is associated with large-scale motions with high Reynolds shear stress in the outer layer.

• 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.