• Journal of Advanced Navigation Technology
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• v.17 no.1
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• pp.123-131
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• 2013

If Industrial state-of-the-art technology that made through IT convergence should be to build safely environment that can protect then IT technology and manufacturing industry become convergence and a growth engine become stable positioning. In each industry, there has been a steady effort for the industrial security. However, they introduced only managerial/technical/physical countermeasures. Therefore, it is difficult to find a reference point as industrial security necessity, protecting coverage and things and so on. It is to lack that academic research in industrial security for protecting industrial technology. In detail, a clear definition lack for industrial security. And target range classification lack for industrial security studies. In this study, we redefined the concept of industry security through previous studies. Academic classification designed industrial security studies through delphi method. we analyzed industry security trends based industrial security studies classification and presented domestic industry research orientations.

• Journal of KIISE:Information Networking
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• v.34 no.3
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• pp.193-202
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• 2007

In this paper, a performance evaluation model of the Multistage Interconnection Network(MIN) with the multiple-buffered crossbar switches under Hot-spot environment is proposed and examined. Buffered switch technique is well known to solve the data collision problem of the MIN. The proposed evaluation model is developed by investigating the transfer patterns of data packets in a switch. The performance of the multiple-buffered $a{\times}a$ crossbar switch is analyzed. Steady state probability concept is used to simplify the analyzing processes. Two important parameters of the network performance, throughput and delay, are then evaluated. To validate the proposed analysis model, the simulation is carried out on a Baseline network that uses the multiple buffered crossbar switches. Less than 2% differences between analysis and simulation results are observed. It is also shown that the network performance is significantly improved when the small number of buffer spaces is given. However, the throughput elevation is getting reduced and network delay becomes increasing as more buffer spaces are added in a switch.

• Journal of KIISE:Information Networking
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• v.32 no.2
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• pp.244-253
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• 2005

In this paper, a performance evaluation model of the switch router with the multiple-buffered crossbar switches is proposed and examined. Buffered switch technique is well known to solve the data collision problem of the crossbar switch. The proposed evaluation model is developed by investigating the transfer patterns of data packets in a switch with output-buffers. The performance of the multiple-buffered crossbar switch is analyzed. Steady state probability concept is used to simplify the analyzing processes. Two important parameters of the network performance, throughput and delay, are then evaluated. To validate the proposed analysis model, the simulation is carried out on a network that uses the multiple buffered crossbar switches. Less than $2\%$ differences between analysis and simulation results are observed. It is also shown that the network performance is significantly improved when the small number of buffer spaces is given. However, the throughput elevation is getting reduced and network delay becomes increasing as more buffer spaces are added in a switch.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.08a
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• pp.305-305
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• 2010

It is known that a pulse of electrons of high kinetic energy (1-3 eV) in metals can be generated with the deposition of external energy to the surface such as in the absorption of light or in exothermic chemical processes. These energetic electrons are not in thermal equilibrium with the metal atoms and are called "hot electrons" The concept of photon energy conversion to hot electron flow was suggested by Eric McFarland and Tang who directly measured the photocurrent on gold thin film of metal-semiconductor ($TiO_2$) Schottky diodes [1]. In order to utilize this scheme, we have fabricated metal-semiconductor Schottky diodes that are made of Pt or Au as a metallic layer, Si or $TiO_2$ as a semiconducting substrate. The Pt/$TiO_2$ and Pt/Si Schottky diodes are made by PECVD (Plasma Enhanced Chemical Vapor Deposition) for $SiO_2$, magnetron sputtering process for $TiO_2$, e-beam evaporation for metallic layers. Metal shadow mask is made for device alignment in device fabrication process. We measured photocurrent on Pt/n-Si diodes under AM1.5G. The incident photon to current conversion efficiency (IPCE) at different wavelengths was measured on the diodes. We also show that the steady-state flow of hot electrons generated from photon absorption can be directly probed with $Pt/TiO_2$ Schottky diodes [2]. We will discuss possible approaches to improve the efficiency of photon energy conversion.

• Tunnel and Underground Space
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• v.18 no.5
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• pp.366-374
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• 2008

Tunnelling under water table induces many geotechnical problems because of groundwater. In subsea tunneling, reduction of face stability can induce flooding in the vicinity of a fracture zone characterized by high permeability and high water pressure. In this study, the effects of high water pressure on the stability of a tunnel face in a limited zone with high permeability(hazardous zone) are analyzed. On the basis of the 'advance core' concept, the seepage force acting on a hypothetical cylinder ahead of a tunnel face is modeled. This study focuses on the hydraulic behavior of the ground ahead of the tunnel face by three-dimensional steady-state seepage analyses. The impact of the hazardous zone on the seepage force and stability of the tunnel face are simulated and analyzed. In light of the analysis results, it is estimated that the distance from the tunnel face to the exterior boundary limit, which the seepage force significantly affects the stability of the tunnel face, of a hypothetical cylinder is approximately 5 times the tunnel radii. Despite the restrictive assumptions of this study, the results are highly indicative regarding the risks of hazardous zones.

• Journal of KIISE:Information Networking
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• v.29 no.6
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• pp.738-748
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• 2002

In this paper, a performance evaluation model of the Multistage Interconnection Network(MIN) with the multiple-buffered crossbar switches is Proposed and examined. Buffered switch technique is well known to solve the data collision problem of the MIN. The proposed evaluation model is developed by investigating the transfer patterns of data packets in a switch with output-buffers. The performance of the multiple-buffered${\alpha}{\times}{\alpha}$ crossbar switch is analyzed. Steady state probability concept is used to simplify the analyzing processes, Two important parameters of the network performance, throughput and delay, are then evaluated, To validate the proposed analysis model, the simulation is carried out on a Baseline network that uses the multiple buffered crossbar switches. Less than 2% differences between analysis and simulation results are observed. It is also shown that the network performance is significantly improved when the small number of buffer spaces is given. However, the throughput elevation is getting reduced and network delay becomes increasing as more buffer spaces are added in a switch.

• Nuclear Engineering and Technology
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• v.51 no.8
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• pp.1871-1885
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• 2019

The deterministic MOC code STREAM of the Computational Reactor Physics and Experiment (CORE) laboratory of Ulsan National Institute of Science and Technology (UNIST), was initially designed for the calculation of pressurized water reactor two- and three-dimensional assemblies and cores. Since fast reactors play an important role in the generation-IV concept, it was decided that the code should be upgraded for the analysis of fast neutron spectrum reactors. This paper presents a coupled code - TULIP/STREAM, developed for the fast reactor assembly and core calculations. The TULIP code produces self-shielded multi-group cross-sections using a one-dimensional cylindrical model. The generated cross-section library is used in the STREAM code which solves eigenvalue problems for a two-dimensional assembly and a multi-assembly whole reactor core. Multiplication factors and steady-state power distributions were compared with the reference solutions obtained by the continuous energy Monte-Carlo code MCS. With the developed code, a sensitivity study of the number of energy groups, the order of anisotropic P_N scattering, and the multi-group cross-section generation model was performed on the k_eff and power distribution. The 2D core simulation calculations show that the TULIP/STREAM code gives a k_eff error smaller than 200 pcm and the root mean square errors of the pin-wise power distributions within 2%.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.21 no.3
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• pp.239-245
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• 2008

A level set based topological shape optimization using extended B-spline basis functions is developed for steady-state heat conduction problems. The only inside of complicated domain identified by the level set functions is taken into account in computation, so we can remove the effects of domain outside parts in heat conduction problem. The solution of Hamilton-Jacobi equation leads to an optimal shape according to the normal velocity field determined from the sensitivity analysis, minimizing a thermal compliance while satisfying a volume constraint. To obtain exact shape sensitivity, the precise normal and curvature of geometry need to be determined using the level set and B-spline basis functions. Using topological derivative concept, the nucleation of holes for topological changes can be made whenever and wherever necessary during the optimization.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2004.03a
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• pp.671-686
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• 2004

The shock-induced combustion ramjet (shcramjet) is a hypersonic airbreathing propulsion concept which over-comes the drawbacks of the long, massive combustors present in the scramjet by using a standing oblique detonation wave (a coupled shock-combustion front) as a means of nearly instantaneous heat addition. A novel shcramjet combustor design that makes use of wedge-shaped flameholders to avoid detonation wave-wall interactions is proposed and analyzed with computational fluid dynamics (CFD) simulations in this study. The laminar, two-dimensional Navier-Stokes equations coupled with a non-equilibrium hydrogen-air combustion model based on chemical kinetics are used to represent the physical system. The equations are solved with the WARP (window-allocatable resolver for propulsion) CFD code (see: Parent, B. and Sislian, J. P., “The Use of Domain Decomposition in Accelerating the Convergence of Quasihyperbolic Systems”, J. of Comp. Physics, Vol. 179, No. 1,2002, pages 140-169). The solver was validated with experimental results found in the literature. A series of steady-state numerical simulations was conducted using WARP and it was deter-mined by means of thrust potential calculations that this combustor design is a viable one for shcramjet propulsion: assuming a shcramjet flight Mach number of twelve at an altitude of 36,000 m, the geometrical dimensions used for the combustor give rise to an operational range for combustor inlet Mach numbers between six and eight. Different shcramjet flight Mach numbers would require different combustor dimensions and hence a variable geometry system in or-der to be viable.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.1079-1081
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• 2007

An L-band Linear Accelerator System for E-beam sterilization is under construction for bio-technology application. The klystron-modulator system as an RF microwave source has an important role as major components to offer the system reliability for long time steady-state operations. A PFN line type pulse generator with a peak power of 71.5-MW, $7\;{\mu}s$, 285 pps is required to drive a high-power klystron. The high power pulse transformer has a function of transferring pulse energy from a pulsed power source to a high power load. The pulse transformer producing a pulse with a peak voltage of 275 kV is required to produce 30-MW peak and 60 kW average RF output power at the frequency of 1.3-GHz. We have designed the high power pulse transformer with 1:13 step-up ratio. The peak and average power capability is 71.5-MW (275 kV, 260 A at load side with $7\;{\mu}s$ pulse width) and 130 kW, respectively. In this paper, we present measurements and its analysis on the design parameters, and an initial test result as well as a design concept on the high-power pulse transformer.