• The Journal of the Acoustical Society of Korea
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• v.16 no.1
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• pp.81-87
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• 1997

In this paper, a new pre-processing method for the recognition of single vowels by use of spectrum envelope is presented. We use new extraction method of a spectrum envelope using the diffusion filter bank. By dividing analysis band of a diffusion filter bank into subbands, we decreased the number of diffusion process. And, by increasing the number of difference, we got higher selectivity. As a result of them, we reduced the total processing time, and got higher enhancement of discrimination. By getting 88.3% of average recognition rate for single vowels of natural voice through computer simulation. We confirmed it to be useful for speech recognition which use spectrum analysis of the voice signal to have many frequency components.

• 프린팅코리아
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• v.7 no.12
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• pp.109-111
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• 2008

2007년에는 인터넷의 광고비가 잡지의 광고비를 추월했다. 이런 현상은 전자미디어의 활용이 지속적으로 확대되고 있으며 다매체 미디어 시대로 전환되고 있다는 것을 뜻한다. 그런 가운데 인쇄의 유효성은 다시 각광 받고 있다. 다른 미디어가 할 수 없는 오감에 호소하는 특수한 인쇄 및 가공을 활용함으로써 부가가치를 창출하는데 유용하다는 인식이 확산되고 있는 것이다. 최근 들어 관심을 끌고 있는 제품과 기법을 소개한다.

• Journal of the Korea institute for structural maintenance and inspection
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• v.19 no.1
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• pp.90-99
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• 2015

This study examined dynamic and characteristics and chloride penetration of concrete mixed with large amount of FA and BFS, which are considered for positive application to construction fields with purpose of long-tern durability of concrete structures. As a result of strength test on FA and BFS, FA concrete showed higher increase of strength compared to OPC, when FA4000 and FA5000 were mixed 30%, respectively. For BFS concrete, those mixed with 30% and 50% of BFS8000, respectively, showed higher or equivalent strength compare to OPC. As a result of test of chloride penetration on FA and BFS, diffusion coefficients of concrete mixed with 30% FA4000 and FA5000, respectively, showed to restrain average 6.5% of diffusion coefficient compared to OPC. And in case of BFS concrete, those mixed with BFS6000 and BFS8000, restrained diffusion of chloride ions 253% and 336%, respectively, compared to OPC. Therefore, Mixing 50% of BFS was most efficient in order to maximize restraint of chloride penetration according to metathesis of large amount. For relation between compression strength and diffusion coefficient of FA and BFS concrete, as strength increased, diffusion coefficient decreased. In this study, when mixing FA and BFS to concrete for long-run durability and restraint against chloride penetration, for FA, mixing it to concrete with less or equivalent 30% of replacement rate was most efficient. And for BFS, as fineness was higher and mixing it to concrete with less or equivalent 50% of replacement rate, there were results of higher strength compared to OPC and more efficient restraint of chloride ions.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.29 no.10 s.241
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• pp.1075-1082
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• 2005

The characteristics of longitudinal dispersion enhancement by the flow oscillation are numerically studied according to various groove geometries in a 2-D channel in the present study. The length of expanded section l$_{1}$/h$_{1}$ is varied from 0 to 8.75. The oscillating flow condition is given at both side ends, i.e., u = Asin ($2{\pi}ft$) The non-dimensional temperatures at both side ends are set to zero. The bottom and top walls are adiabatic. The local heat sources are located at the middle of the groove wall. In order to solve the governing equations, the SIMPIER algorithm is employed. The present results indicate that maximum longitudinal thermal dispersion can be achieved when the area ratio of the expanded section to the contracted section in the grooved channel becomes 1.

• Proceedings of the Membrane Society of Korea Conference
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• 1993.10a
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• pp.56-57
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• 1993

고분자 막을 통한 투과증발에서의 전달기구는 액체 혼합액의 막으로의 용해, 막을 통한 확산, 막 하부에서의 증발을 거쳐 분리가 일어난다고 알려져 있다. 이때 투과증발의 선택도는 수착선택도와 확산선택도의 곱으로 표현 될 수 있다(1). 물의 선택적 분리의 관점에서 친수성 고분자 막을 이용하는 경우, 선택도는 대부분 수착선택도에 기인하며, 우수한 투과속도와 함께 집중적인 연구의 대상이 되었으나 가소화 현상이 심하게 일어나는 단점이 있다. 한편 소수성 고분자 막을 이용하는 경우의 투과 증발 선택도는 대부분 확산선택도에 기인하며, 가소화 현상은 억제되나 투과속도가 낮은 단점이 있다. 그러나 소수성 고분자 막을 이용하는 경우에도 물에 대해 높은 선택도를 달성 할 수 있는데, 예를 들어 polystyrene(PS)으로 만들어진 고분자 막 및 fluoroalkylacrylatemethylstyrene copolymer로 만들어진 고분자 막은 물-에탄올 공급액으로 부터 물에 대한 높은 선택성을 보여주고 있다(2,3). 그러므로 막분리층의 두께를 가능한 한 얇게 하면 분리에 유효한 막이 될 수 있다.

• Water for future
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• v.12 no.1
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• pp.56-59
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• 1979

A prompt subsurface runoff producing mechanism whih creaters a depletion curve of direct runoff hydrograph is simulated by a dead zone dispersion model technique. Runoff processes are carried out by routing of the outflow resulted from previous linear channel and effective rainfall from its corresponding subwatershed through a series of conceptual linear channels representing subwatersheds of a catchment. Working rules are explained for evaluation the model parameters such as translatory velocity, diffusive factor, and parameters concerning the infiltration and relative magnitude of the prompt subsurface flow region.

• Journal of the Korea Convergence Society
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• v.13 no.1
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• pp.261-268
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• 2022

It is a common situation to limit entrance to the multi-use buildings for efficient control and prevention of the spread of COVID-19. This study chiefly aims to find out efficient methods to establish evacuation plans when temporary changes of the building circulation system occurs. If architectural design were done with the pre-consideration for the changes of building circulation systems, through the analysis of multi-use buildings, it is expected to we can prevent the spread of disasters when they happen. This study is geared to establish efficient evacuation plan for the temporary circulation plan when disaster happen, through the analysis of multi-use buildings for architectural planning as well as the human behavioral patterns.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.30 no.5
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• pp.71-78
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• 2002

Experiments have been performed using two-color PIV in hydrogen non-premixed flames with various conditions of coaxial air, which was classified into three cases with/without reaction. Mean velocity, turbulence intensity and Reynolds stress were analyzed using flow fields from PIV measurement First, the similarity of pure jet had a good agreement with previous results of other researchers. It was found that the decay of centerline velocity was proportional to $x^{-1}$ in coaxial air conditions. By normalizing axial distance with effective jet diameter defined by effective density, the data of centerline velocity collapsed a single line. And the radial profiles of mean velocity showed that they didn't become self-similar because the curves differed from each other as coaxial air velocity increased at fixed fuel velocity. Also, turbulence intensity became self-similar further downstream than mean velocity.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2012.05a
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• pp.397-402
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• 2012

The objective of this study is the estimation of the two unknown thermal conductivity and thermal diffusivity by an inverse heat conduction analysis using the Levenberg-Marguardt method. One dimensional formulation of heat conduction problem in the model was applied. Two point transient temperature of test pieces and heat flux of inflow were measured under the high enthalpy flow environment. Estimated thermal conductivity and thermal diffusivity by an inverse analysis were compared with the known values of graphite test piece. It showed the effectiveness of proposed experimental inverse analysis.

• Tunnel and Underground Space
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• v.13 no.1
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• pp.20-32
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• 2003

To understand the behavior of migration of contaminants in a fractured porous medium is a key to assure the overall safety of a potential radwaste repository. The feasible retention mechanism of contaminant transport in a tinctured medium are sorption of contaminants on solid surface and matrix diffusion of contaminants from a fracture into an adjacent porous medium. The acceleration mechanisms are the migration of contaminants in the form of pseudo-colloids and the limit of a volume f3r matrix diffusion. In this paper, the effects of these two acceleration mechanisms are studied mathematically, then semi-analytically computed by the application of the Talbot theorem and verified. Results indicate that the acceleration processes cannot be neglected in the modeling of contaminant transport in a fractured porous medium.