• KSII Transactions on Internet and Information Systems (TIIS)
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• 제11권4호
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• pp.2124-2148
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• 2017

Accurate facial expression recognition (FER) requires reliable signal filtering and the effective feature extraction. Considering these requirements, this paper presents a novel approach for FER which is robust to noise. The main contributions of this work are: First, to preserve texture details in facial expression images and remove image noise, we improved the anisotropic diffusion filter by adjusting the diffusion coefficient according to two factors, namely, the gray value difference between the object and the background and the gradient magnitude of object. The improved filter can effectively distinguish facial muscle deformation and facial noise in face images. Second, to further improve robustness, we propose a new feature descriptor based on a combination of the Histogram of Oriented Gradients with the Canny operator (Canny-HOG) which can represent the precise deformation of eyes, eyebrows and lips for FER. Third, Canny-HOG's block and cell sizes are adjusted to reduce feature dimensionality and make the classifier less prone to overfitting. Our method was tested on images from the JAFFE and CK databases. Experimental results in L-O-Sam-O and L-O-Sub-O modes demonstrated the effectiveness of the proposed method. Meanwhile, the recognition rate of this method is not significantly affected in the presence of Gaussian noise and salt-and-pepper noise conditions.

• 한국컴퓨터그래픽스학회논문지
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• 제21권5호
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• pp.1-10
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• 2015

본 연구는 가상 조경을 구성하는 다양한 종류의 디지털 잎을 쉽고 직관적으로 제작할 수 있는 저작도구 개발방법을 제안한다. 제안하는 저작도구의 핵심 시스템은 영상 워핑기반의 잎몸 윤곽선 변형 방법, 잎맥의 절차적 모델링 그리고 잎의 색과 명암 등을 표현하기 위한 수리모델기반 시각화 방법으로 구성된다. 우선 잎 영상을 입력으로 받아 잎몸에 대한 윤곽선 정보를 찾고, 특징기반 영상 워핑을 활용하여 다양한 잎몸 형상을 직관적인 구조에서 쉽게 생성할 수 있는 잎몸 변형 방법을 설계한다. 그리고 계산된 잎몸 윤곽선을 기반으로 잎몸 형상에 적합한 자연스러운 잎맥 패턴을 생성하는 일반화된 절차적 모델링 방법을 저작도구에 맞게 구현한다. 마지막으로 약수 함수의 합성 기반의 수리모델을 활용하여 잎의 색, 명암 그리고 시간에 따른 변화를 표현할 수 있는 시각화 기능을 적용한다. 제안한 저작도구를 활용하여 제작된 디지털 잎이 다양한 3차원 디지털 콘텐츠 분야에 활용 가능하도록 텍스쳐 지원 기능을 제공한다.

• 한국재료학회지
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• 제25권3호
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• pp.149-154
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• 2015

We evaluated the developed microstructures and mechanical properties of a severely plastically deformed Ni-30Cr alloy. Normal rolling and differential speed rolling were used as deformation processes, and the thicknesses of the specimens were reduced to 68 % of the original thickness after holding at $700^{\circ}C$ for 10 min and annealing at $700^{\circ}C$ for 40 min to obtain a fully recrystallized microstructure. Electron backscattering diffraction was used to analyze the characteristic distribution of the grain boundaries on the deformed and annealed specimens. Differential speed rolling was more effective for refining grains in comparison with normal rolling. The grain size was refined from 33 mm in the initial material to 8.1 mm with normal rolling and 5.5 mm with differential speed rolling. The more refined grain in the differential-speed-rolled material directly resulted in increases in the yield and tensile strengths by 68 % and 9.0%, respectively, compared to normal rolling. We systematically explain the relationship between the grain refinement and mechanical properties through a plastically deformed Ni-30Cr alloy based on the development of a deformation texture. The results of our study show that the DSR process is very effective when used to enhance the mechanical properties of a material through grain refinement.

• 산업식품공학
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• 제22권4호
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• pp.381-385
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• 2018

즉석밥의 물성을 효율적으로 측정하기 위한 방법을 모색하고자 다양한 경도를 가진 즉석밥을 대상으로 4가지 다른 물성 기법을 적용하고 그 경도 결과를 비교 분석하였다. 이를 위해 disk, cylinder, rod, cone probe를 사용한 물성 측정법을 즉석밥에 적용하여 이들의 상관관계를 조사하였다. 모든 측정 방법에 대하여 수분함량에 따른 경도와의 상관관계를 분석한 결과 비교적 높은 음의 선형관계를 보여주어 수분함량이 증가할수록 경도가 감소하는 패턴을 명확히 보여주었다. Cone probe 측정법의 경우 압축력과 전단력을 통한 개별 밥알 시료의 변형이 가능하여 가장 높은 상관관계를 보여주었고, disk probe 측정법 또한 높은 양의 상관관계를 보였지만 죽과 같이 유동성을 가진 시료에는 적용이 어려웠다. 더 나아가 측정된 힘 값을 응력 형태로 전환시켜 상호 비교한 결과 cone과 rod probe 방법 그리고 rod와 cylinder probe 방법의 Pearson 계수가 0.9에 가까운 높은 상관관계를 보여주었다. 본 연구를 통하여 얻어진 결과는 즉석밥의 물성 측정을 위한 다양한 기법을 좀 더 이해하는데 기여할 수 있을 것으로 판단되며, 다양한 형태의 즉석밥을 개발하는데 활용될 수 있을 것으로 기대된다. 아울러, 본 연구를 통해서 얻어진 기계적 측정 결과와 관능평가 결과를 연관 지을 수 있다면 실제 식품 산업에서 활용될 수 있는 보다 의미 있는 결과를 제공할 수 있어 이에 대한 후속 연구가 필요하다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2014년도 제46회 동계 정기학술대회 초록집
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• pp.361.1-361.1
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• 2014

PbVO3 (PVO), a polar magnetic material considered as a candidate of multiferroic, has ferroelectricity along the c-axis and 2-dimensional antiferromagnetism lying in the in-plane through epitaxial growth [1,2]. PVO thin films were grown on LaAlO3 (001) substrates under reduction atmosphere from a stable Pb2V2O7 sintered target using pulsed laser deposition method. Epitaxial growth of the PVO films is possible only under Ar atmospheren with no oxygen partial pressure. X-ray diffraction was used to investigate the phase formation and texture of the films. We confirmed epitaxial growth of the PVO films with crystalline relationship of PbVO3[001]//LaAlO3[001] and PbVO3[100]//LaAlO3[100]. In addition, surface morphology of the films displays drastic changes in accordance with the growth conditions. Elongated PVO grains are related to the Pb2V2O7 pyrochlore structure. The relation between structural deformation and ferroelectricity in the PVO films was examined by local measurement of piezoresponse force microscopy.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2005년도 추계학술대회 논문집
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• pp.381-383
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• 2005

극저온 압연중인 알루미늄 합금의 미세조직의 변화 - 집합조직의 발전과 결정립 크기 및 형상 변화 -를 예측할 수 있는 오일러리안 유한요소 해석을 수행하였다. 패스 당 압하율 $30\%$ 인 연속 세 패스의 압연공정을 시뮬레이션 하여 얻은 결과는 실험에서 관측된 것과 비슷한 경향을 보여, 본 연구의 해석모델의 타당성을 입증하였다.

• 한국재료학회지
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• 제22권11호
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• pp.581-586
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• 2012

The microstructure and mechanical properties of a copper alloy sheet processed by differential speed rolling (DSR) were investigated in detail. A copper alloy with thickness of 3 mm was rolled to a 50% reduction at ambient temperature without lubrication and with a differential speed ratio of 2.0:1. For comparison, conventional rolling (CR), in which the rolling speeds of the upper and lower rolls is 2.0 m/min, was also performed under the same rolling conditions. The shear strain of the sample processed by CR showed positive values at the positions of the upper roll side and negative values at the positions of the lower roll side. On the other hand, the sample processed by the DSR showed zero or positive shear strain values at all positions. However, the microstructure and mechanical properties of the as-rolled copper alloys did not show such significant differences between the CR and the DSR. The samples rolled by the CR and the DSR exhibited a typical deformation structure. In addition, the DSR processed samples showed a typical rolling texture in which {112}<111>, {011}<211> and {123}<634> components were developed at all positions. Therefore, it is concluded that the DSR was very effective for the introduction of a uniform microstructure throughout the thickness of the copper alloy.

• 소성∙가공
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• 제27권1호
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• pp.12-17
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• 2018

This paper outlines the research findings on the microstructure and mechanical properties of AZ31 Mg alloy fabricated by differential speed rolling (DSR) with respect to processing variables such as temperature, roll speed ratio (RSR), and deformation route. The resultant microstructure of the sample, deformed by 2-pass DSRs at 473 K, comprised finer grains with more uniform distribution than those at 573 and 623 K. This was due to active recrystallization, which was expected to appear during DSR at temperatures higher than 573 K. When the sample was deformed via DSR with RSR of 1:4 for the upper and lower rolls at 453 K, the values of yield and ultimate tensile strength were observed to be higher than their counterpart with RSR of 1:1. The application of sample rotation around the longitudinal axis would give rise to an excellent combination of tension strength (~330 MPa) and ductility (~20 %) at ambient temperatures. This is discussed based on its uniform fine grained structure and the softening of basal texture.

• 한국안전학회지
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• 제27권3호
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• pp.15-19
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• 2012

The fatigue behavior of AM60 magnesium alloy produced by equal channel angular pressing(ECAP) process was investigated through fatigue lifetime and fatigue crack propagation rate tests. The grain structure of the material was refined from 19.2 ${\mu}m$ to 2.3 ${\mu}m$ after 6 passes of ECAP at 493 K. The yield strength(YS) and ultimate tensile strength (UTS) increase after two passes but decrease with further pressing, although the grain size becomes finer with increasing pass number. The softening effect due to texture anisotropy overwhelmed the strengthening effect due to grain refinement after 2 passes. A large enhancement in fatigue strength was achieved after two ECAP passes. The current finding suggests that two passed material is better than the multi-passed material in view of the static strength and fatigue performance.

• 한국공작기계학회논문집
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• 제12권5호
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• pp.34-39
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• 2003

The paper will present chip formation mechanism and surface integrity generation mechanism based on the systematical experimental tests. Some basic factors such as the end milling cutter tooth number, cutting forces, cutting temperature, cutting vibration the chip status, the surface roughness, the hardness distribution and the metallographic texture of the machined surface layer are involved. The chip formation mechanism is typical thermal plastic shear localization at high cutting speed with less number of shear ribbons and bigger shear angle than that at low speed, which means lack of chip deformation. The high cutting speed with much more cutting teeth will be beneficial to the reduction of cutting forces, enlarge machining stability mot depression of temperature increment anti-fatigability as well as surface roughness. The burrs always exist both at low cutting speed and at high cutting speed. So the deburring process should be arranged for milling titanium alloy in my case.