• The Journal of Korean Institute of Communications and Information Sciences
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• v.39C no.3
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• pp.209-222
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• 2014

NCW is a new operational concept for modern warfare to improve the ability to conduct combat by connecting command and control system via network. To realize NCW integrating information sharing system between multiple platforms, CDL is considered as a key component for high-speed transmission of ISR data. Accordingly, further studies to enhance the performance of CDL are being performed around the world, and our government has also developed self-reliant CDL, MPI-CDL. However, the maximum data rate and networking performance of current CDL still fall short of the objective to enable multiple systems to share the large ISR data. Therefore, in this paper, we analyze the development flow and international technical trends of CDL, and present an approach for enhancing data rate and networking capacity of the next generation CDL.

• Journal of Biomedical Engineering Research
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• v.15 no.3
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• pp.317-324
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• 1994

This paper proposed a new method in the implementation of ISDN (integrated services digital network) LAPD (link access procedure on the D-channel) and LAPB (link access procedure on the B-channel) protocols. The proposed method in this paper implement ISDW LAPD protocol through multi-tasking operating system and adopt a kernel part that is changed operating system to target board. The features of implemented system are (1) the para.llel processing of the events generated at each layer, as follows (2) the supporting necessary timers for the implementation of ISDW LAPD protocol from the kernel part by using software, (3) the recommanded SAP (Service Access Point) from CCITT was composed by using port function in the operating system. With the proposed method, the protocols of ISDH layerl, layer2 and layer3 (call control) were implemented by using the kernel part and related tests were carried out by connecting the ISDH terminal simulator to ISDN S-interface system using the ISDN LAPD protocol The results showed that ISDW S-interface terminals could be discriminated by TEI (Terminal Equipment Identifier) assignment in layer 2 (LAPD) and the message transmission of layer 3 was verified by establishing the multi-frame transmission and then through the path established by the LAPD protocol, a user data was tranfered and received on B-channel with LAPB protocol Thererfore, as new efficient ISDN S-interface environment was implemented in the thesis, it was verified that the implemented system can be utilized by connecting ISDW in the future to transfer a medical image data.

• Journal of Energy Engineering
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• v.26 no.3
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• pp.123-130
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• 2017

The district heating system has been successfully implemented with higher efficiency levels of energy production and reduction of carbon emissions during heat generation. Traditionally the system consisted of small number of production and demand sites, but, recently it has evolved into a network with large number of sites interconnected each other. By connecting multiple sites into a network, heat from low-cost production sites can be supplied to distant demand sites so as to lower the total operation cost. In this study, we simulate and analyze distict heating networks focused on critical links. a critical link is defined as a link in which capacity is fully utilized. If a newtork has critical links, then those cricial links become bottlenecks and it is difficult to improve the overall network efficiency.

• The Journal of the Korea Contents Association
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• v.6 no.9
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• pp.9-18
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• 2006

We completed a new cluster system based on WDM by proposing a virtual topology reconfiguration schemes. The key idea of the proposed scheme is to construct a set with the longest chains of requests of connecting nodes which need to be assigned a wavelength. All the sets have no common factor, that is, there is no duplicated link among the requests of connecting. After making the set satisfying this condition, we could assign a wavelength to per corresponding set. We could reconfigure a virtual topology with this scheme collectively. we compared our scheme to existing approaches by the OWns simulation tool. As the results, we gained improved performances, reducing 10% of blocking rate and improving 30% of ADM utilization in terms of the blocking probability and the ADM utilization.

• The Journal of the Korea Contents Association
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• v.8 no.1
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• pp.160-168
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• 2008

We completed a new cluster system based on WDM by proposing virtual topology reconfiguration schemes. The key idea of the proposed scheme Is to construct a set with the longest chains of requests of connecting nodes which need to be assigned a wavelength. All the sets have no common factor, that is, there is no duplicated link among the requests of connecting. After making the set satisfying this condition, we could assign a wavelength to per corresponding set. We could reconfigure a virtual topology with this scheme collectively. we compared our scheme to existing approaches by the OWns simulation tool. As the results, we gained improved performances, reducing 10% of blocking rate and improving 30% of ADM utilization in terms of the blocking probability and the ADM utilization.

• Computers and Concrete
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• v.3 no.1
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• pp.65-77
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• 2006

This study reports the details of the finite element analysis of eleven shear critical partially prestressed concrete T-beams having steel fibers over partial or full depth. Prestressed concrete T-beams having a shear span to depth ratio of 2.65 and 1.59 and failing in the shear have been analyzed using 'ANSYS'. The 'ANSYS' model accounts for the nonlinear phenomenon, such as, bond-slip of longitudinal reinforcements, post-cracking tensile stiffness of the concrete, stress transfer across the cracked blocks of the concrete and load sustenance through the bridging of steel fibers at crack interface. The concrete is modeled using 'SOLID65'-eight-node brick element, which is capable of simulating the cracking and crushing behavior of brittle materials. The reinforcements such as deformed bars, prestressing wires and steel fibers have been modeled discretely using 'LINK8' - 3D spar element. The slip between the reinforcement (rebar, fibers) and the concrete has been modeled using a 'COMBIN39'-non-linear spring element connecting the nodes of the 'LINK8' element representing the reinforcement and nodes of the 'SOLID65' elements representing the concrete. The 'ANSYS' model correctly predicted the diagonal tension failure and shear compression failure of prestressed concrete beams observed in the experiment. The capability of the model to capture the critical crack regions, loads and deflections for various types of shear failures in prestressed concrete beam has been illustrated.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.17 no.2
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• pp.95-104
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• 2017

We investigate the God gate olleh of the largest tomb, pyramid, in the world which is scattered in Jeju Island and construct link which is connecting Jeju people's custom to modern science. The three sacred gates and the two tombs are connected to the olegil space. In this space, the principle of complementarity in which coexistence exist between life and death is hidden in Jeju culture. It is a question and wait. Contrarily, the opposite is complementary. (Contraria Sunt Complementa Latin) This refers to the relationship of each other in relation to one another and in a mutually dependent relationship. Seminal vesicles are used as basic logic in DNA codon of human body as well as communication principle.

• Progress in Superconductivity and Cryogenics
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• v.20 no.4
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• pp.55-59
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• 2018

Currently, the development of industry makes needs larger electric supply. Providers must consider the efficiency about losses and reliability of the system. In this case, DC power system can save electrical energy; long-distance transmission line losses. Relevance to switch technology with a voltage-source converter (VSC) in AC-DC conversion system have been researched. But, protection device of DC-link against fault current is still needed to study much. VSC DC power system is vulnerable to DC-cable short-circuit and ground faults, because DC-link has a huge size of capacitor filter which releases extremely large current during DC faults. Furthermore, DC has a fatal flaw that current zero crossing is nonexistence. To interrupt the DC, several methods which make a zero crossing is used; parallel connecting self-excited series LC circuit with main switch, LC circuit with power electronic device called hybrid DC circuit breaker. Meanwhile, self-excited oscillator needs a huge size capacitor that produces big oscillation current which makes zero crossing. This capacitor has a quite effective on the price of DCCB. In this paper, hybrid self-excited type superconducting DCCB which are using AC circuit breaker system is studied by simulation tool PSCAD/EMTDC.

• Journal of Korean Elementary Science Education
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• v.27 no.1
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• pp.83-92
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• 2008

In this study, we developed elementary science education modules for facilitating students' understanding of the connected nature of Science-Technology-Society. For these modules, we particularly used news articles to make connections among science, technology, and society. We set up the development criteria as followings: connecting science-technology-society, aligning with national science curriculum, respecting students' interest, and appropriating the difficulty levels in terms and concepts. We also studied 4th grade students' perception of using these modules in science lessons. Most students perceived that using the modules in their science classes helped them link science-technology-society intimately and enhance their interest and motivation, as well as their self-esteem for studying science.

• Proceedings of the IEEK Conference
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• 1998.10a
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• pp.417-420
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• 1998

A heuristic sweeping algorithm for an autonomous smearing robot which executes the area filling task is proposed. This algorithm searches tracking points with the obstacle andenvironment wall while the robot tracking whole workspace, and finds sequential tracking line by sequentally connecting the tracking points in such a way that (1) the line should be never crossed, (2) the total tracking points should be is linked as short as possible, and (3) the tracking link should be cross over the obstacle in the work-space. If the line pass through the obstacle, hierarchical collision free algorithm proposed is implied. The proposed algorithm consists of (1) collision detection procedure, (2) obstacle map making procedures, (3) tracking points generation procedures for subgosls, (4) tracking points scanning procedures, and (5) obstacle avoidance procedure.