• Proceedings of the Acoustical Society of Korea Conference
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• 1998.06e
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• pp.407-410
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• 1998

본 논문에서는 변형된 Teager 에너지를 이용하여 음성의 끝점을 검출하는 알고리듬을 제안하였다. 기존의 방법에서는 대부분 음성신호의 에너지와 영교차율을 이용하거나 이 파라미터들과 함께 다른 여러 파라미터들을 사용하여 끝점을 검출하였다. 여러 파라미터들을 사용하는 알고리듬의 경우 계산량이 많아지게 되는데, 이에 비해 본 논문에서는 하나의 파라미터를 이용하기 때문에 계산량이 기존의 알고리듬보다 적다. 그리고 이 알고리듬에서 사용한 변형된 Teager 에너지는 음성신호의 진폭뿐만 아니라 주파수까지 고려한 파라미터이다. 일반적으로 마찰음은 진폭이 작아 검출하기가 어려운데, 본 논문에서는 이러한 마찰음에 대해 실험을 했고, 그 결과를 통해 제안한 알고리듬이 기존의 다른 여러 알고리듬보다 성능이 우수하다는 것을 확인할 수 있었다.

• Journal of the Korean Geotechnical Society
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• v.34 no.2
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• pp.5-17
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• 2018

In this study, the in-situ stress, strength and stress-strain characteristics with shear parameters (UU, CU, ${\bar{CU}}$) are analytically evaluated and the stability analyses are carried out under loading/unloading conditions. The in-situ stress and the stress-strain behaviour may become different according to input shear parameters in finite element analyses with construction step, Especially, if the internal friction angle in Mohr-Coulomb model is set to zero, the in-situ stress and the stress-strain behaviour might not be properly predicted. The results from CU parameter of total stress analysis have no significant difference with the results from CU of effective stress analysis. Therefore, in the numerical analysis for soft ground, CU parameters can be applied to predict in-situ stress and stress-strain behaviors. In addition, the calculation method was proposed to determine the shear parameter of Mohr-Coulomb model, which is corresponding to the shear strength equivalent to that of in-situ soil.

• Journal of Korean Society of Steel Construction
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• v.9 no.4 s.33
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• pp.467-477
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• 1997

A series of experimental tests have been performed on a tube beam in which artificial damage is applied in order to address damage detectability using modal analysis. Modal parameters considered are frequency, displacement mode shape and strain mode shape CoMAC(Coordinate Modal Assurance Criterion) and Modal Vector Error have been adopted for presenting the change of displacement mode shape and strain mode shape. It is revealed strain mode shape is the most sensitive to damage.

• IEMEK Journal of Embedded Systems and Applications
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• v.1 no.1
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• pp.20-23
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• 2006

본 논문은 MB-OFDM UWB(Multi Band-Orthogonal Frequency Division Multiplexing Ultra Wide Band) 시스템을 위한 변형된 가변 파라미터를 이용한 큐빅 인터폴레이터를 제안한다. MB-OFDM UWB 시스템은 고속의 동작속도가 필요하기 때문에, 기존 가변 파라미터를 이용한 큐빅 인터폴레이터에 병렬 처리 기술과 파이프라인 기법을 동시에 적용한다. 실험 결과, Stratix II 2S60F101020C3 디바이스를 타켓으로 최대지연경로 속도와 최대지연경로 주기가 각각 최대 88.79MHz와 11.262ns가 되었고, 동작속도는 최대 대략 200% 이상 향상되었음을 알 수 있다.

• Journal of KIISE:Software and Applications
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• v.28 no.3
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• pp.298-304
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• 2001

Markov 랜덤 필드(MRF)를 이용한 질감 영상의 영역분할을 각 영역을 기술해줄 수 있는 제대로 된 파라미터들을 찾는 것이 가장 중요하다. 종래에는 입력영상의 질감 영역의 수와 그 형태 등을 초기에 적당히 가정하여 파라미터를 찾는 방법을 써왔는데 실제 영상에는 잘 맞지 않았다. 최근에 완화법(Relaxation)을 이용하여 MRF의 파라미터를 찾는 방법이 제안[8]되었는데 오직 일반화된 Ising 모형에서만 사용가능 하였다. 본 논문에서는 비교적 자연영상에 적합한 자기이항 모형(Auto-binomial Model)에 변형된 완화법을 적용시켜 파라미터를 추정하고 질감 영상을 분할해 보았다. 그 결과 이전의 Ising 모형으로는 어려웠던 자연영산의 분할에서 좋은 결과를 얻을 수 있었다.

• Tunnel and Underground Space
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• v.31 no.1
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• pp.66-81
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• 2021

The effects of directional fracture tensor components and first invariant of fracture tensor on deformation moduli and shear moduli of fractured rock masses is analyzed based on regression analysis performed between 3-D fracture tensor parameters and deformability of DFN blocks. Using one or two deterministic joint sets, a total of 224 3-D discrete fracture network (DFN) cube blocks were generated with various configurations of deterministic density and probabilistic size distribution. The fracture tensor parameters were calculated for each generated DFN systems. Also, deformability moduli with respect to three perpendicular direction of the DFN cube blocks were estimated based on distinct element method. The larger the first invariant of fracture tensor, the smaller the values for the deformability moduli of the DFN blocks. These deformability properties present an asymptotic pattern above the certain threshold. It is found that power-law function describes the relationship between the directional deformability moduli and the corresponding fracture tensor components estimated in same direction.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.50 no.4
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• pp.223-231
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• 2022

Residual stress that can occur during the metal additive manufacturing process is an important factor that must be properly controlled for the precise production of metal parts through 3D printing. Therefore, in this study, the factors affecting these residual stresses were investigated using an experimental method. For the experiment, a specimen was manufactured through an additive manufacturing process, and the amount of deformation was measured by cutting it. By appropriately calibrating the measured data using methods such as curve fitting, it was possible to quantitatively analyze the effect of process parameters and metal powder reuse on deformation due to residual stress. From this result, it was confirmed that the factor that has the greatest influence on the magnitude of deformation due to residual stress in the metal additive manufacturing process is whether the metal powder is reused. In addition, it was confirmed that process parameters such as laser pattern and laser scan angle can also affect the deformation.

• Journal of the Korean Institute of Intelligent Systems
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• v.19 no.1
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• pp.96-101
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• 2009

This paper presents a method for identifying the parameter set of inelastic constitutive equations, which is based on an Evolutionary Algorithm. The advantage of the method is that appropriate parameters can be identified even when the measured data are subject to considerable errors and the model equations are inaccurate. The design of experiments suited for the parameter identification of a material model by Chaboche under the uniaxial loading and stationary temperature conditions was first considered. Then the parameter set of the model was identified by the proposed method from a set of experimental data. In comparison to those by other methods, the resultant stress-strain curves by the proposed method correlated better to the actual material behaviors.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.19 no.4
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• pp.41-46
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• 2019

This paper is analysis on usefulness of Microstrip patch antenna design using Taguchi's Orthogonal array. For comparison, the shape of U-slot and Feed line elements are decided as a parameter in Microstrip patch antenna. And all the possible result of 19,683 times simulation using parameter sweep and the result of Taguchi's orthogonal arrays are compared. The simulation of Parameter sweep and Orthogonal arrays has 3.7% error on 10dB Bandwidth. Finally, It is identified that 19,683 times parameter sweep simulation can be reduced to 27 times with Taguchi's orthogonal arrays but still it represents antenna parameter characters well.

• Elastomers and Composites
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• v.42 no.3
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• pp.168-176
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• 2007

When the rubber vulcanizates reinforced with carbon black or silica are subjected to cyclic loading from its virgin state, the stress required on reloading is less than that on the initial loading. This stress softening phenomenon is referred to as the Mullins effect. The strain energy function of rubber vulcanizates was investigated using theory of pseudo-elasticity incorporated damage parameter that Ogden and Roxburgh have proposed to describe the damage-induced stress softening effect in rubber-like solids. The quasi-static cyclic loading test was performed using the NR-SBR vulcanizates reinforced with carbon black, and then the effect of a damage parameter to stress-strain curve in reloading and subsequent reloading paths was studied. The strain energy function of the rubber vulcanizates with a different filler content was also evaluated.