• Journal of Korea Foundry Society
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• v.7 no.4
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• pp.352-357
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• 1987

Recently there were many studies on the development of cast iron for increasing strength, thermal resistance and mechanical properties, etc. The effects on mechanical properties and variation of solidification structure of hypo-eutectic cast iron was investigated when Ni(Al) was added with a fixed quantity of Al(Ni) content. The conclusions are as follows. 1) Tensile strength was the maximum(over 41 kg/ $mm^2$) when Al is added about 0.72%. 2) Torsional strength and angle were increased with increasing Al content and represents maximum value, when Al and Ni content are 1.5 and 2.0%. 3) With increasing Ni content, tensile strength decreased because of the effect of graphite coarsening. But torsional strengths were increased with the appropriate addition of (Ni%+Al%) content because of the effect of strengthened matrix.

• 제어로봇시스템학회:학술대회논문집
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• 1997.10a
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• pp.365-370
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• 1997

In this paper we suggest a development of surface defect inspection algorithms for cold mill strip using tree structure. The defects which exist in a surface of cold mill strip have a scattering or singular distribution. This paper consists of preprocessing, feature extraction and defect classification. By preprocessing, the binarized defect image is achieved. In this procedure, Top-hit transform, adaptive thresholding, thinning and noise rejection are used. Especially, Top-hit transform using local min/max operation diminishes the effect of bad lighting. In feature extraction, geometric, moment, co-occurrence matrix, histogram-ratio features are calculated. The histogram-ratio feature is taken from the gray-level image. For the defect classification, we suggest a tree structure of which nodes are multilayer neural network clasifiers. The proposed algorithm reduced error rate comparing to one stage structure.

• Proceedings of the KIEE Conference
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• 2000.11c
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• pp.449-451
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• 2000

Crosstalk is the primary cause of image distortion in active matrix liquid crystal displays (AMLCD). Crosstalk produces voltage errors that limit gray scale fidelity and consequently, degrades display resolution, contrast ratio, color fidelity, and image quality. In this study, crosstalk phenomena of some methods to compensate level shift voltages has been simulated. This will be contributed to find the way to design the excellent image quality of the TFT-LCDs.

• Journal of Korean Neurosurgical Society
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• v.30 no.12
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• pp.1439-1442
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• 2001

Solitary fibrous tumor(SFT) is a spindle cell neoplasm that usually arises in the pleura. Its involvement of the meninges is rare but increasingly being reported. Our case was a 33-year-old man who presented with clonic seizure around the right mouth angle and sensory disturbance at the right hand. Radiological studies showed a large extra-axial, dural-based mass in the left fronto-parietal region, typically isointense with gray matter and heterogeneous strong enhancement on T1-weighted images. Histologically, the tumor was composed of spindle-shaped cells growing in fascicles within the collagenous matrix. Immunohistochemical staining demonstrated diffuse CD34 positivity. Awareness of this neoplasm is necessary to accurate diagnosis.

• Proceedings of the KSRS Conference
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• 2006.03a
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• pp.275-278
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• 2006

본 연구는 전정색(panchromatic) 고해상도 위성영상을 이용하여 산화피해림과 비산화림을 대상으로 수종별로 구분하여 조사하였다. 제안된 방법은 회색단계 공발생 행렬(Gray Level Co-occurrence Matrix, GLCM)을 통하여 생성된 질감 영상(textural images)과 웨이블릿 분해 영상(wavelet decomposition images)의 융합을 실시하여 질감 영상에서 추출될 수 있는 정보와 웨이블릿 분해를 통해 얻을 수 있는 정보를 획득하고자 하였다. 그 결과로 동일 수종을 형성하는 임반이나 산화피해 정도가 유사한 산림의 경우 영상의 밝기값의 분포가 일정한 범위 내에서 형성되어 수종 분류 및 산화피해 등급의 구분이 가능했으나, 영상 내 경계효과(edge effect) 현상은 일부 영상에서 나타났다.

• Journal of Information Display
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• v.6 no.3
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• pp.1-5
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• 2005

The recent Bistable Nematic ($BiNem^{(R)}$) LCD technology presents long term bistability, high level passive matrix multiplexing, gray levels capabilities and high optical quality. The $BiNem^{(R)}$ device, based on anchoring breaking, needs specific low anchoring strength materials - alignment layers and liquid crystal mixtures. We present here our approach to develop nematic mixtures with wide enough temperature range and low zenithal anchoring energy.

• 한국정보디스플레이학회:학술대회논문집
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• 2008.10a
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• pp.517-520
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• 2008

A voltage-programming pixel circuit, which compensates the threshold voltage shift of TFTs and the degradation of OLED, is proposed for large sized a-Si:H active matrix organic light emitting diode (AMOLED) applications. Considering threshold voltage variation (or shift), OLED degradation and reverse bias annealing, HSPICE simulation results indicate that luminance error of every gray level is less than 0.4 LSB under the condition of +1V threshold voltage shift and from -0.2 LSB to 2.6 LSB within 30% degradation of OLED in the case of 40-inch full HDTV condition.

• 한국정보디스플레이학회:학술대회논문집
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• 2006.08a
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• pp.215-217
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• 2006

This paper presents an area efficient 8-bit current digital to analog convector (DAC) which is applied to 240 channels Active Matrix - Organic Light Emitting Diode (AMOLED) data driver. The proposed circuit constitutes 4-bit binary weighted current DAC and 4-bit switched capacitor cyclic DAC. The proposed DAC has about 70% smaller area than that of the typical binary weighted current DAC. We overcome sampling time by reducing the number of repetition phases so that it can display 8-bit gray scale image.

• Computers and Concrete
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• v.5 no.1
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• pp.61-74
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• 2008

Digital image processing algorithms for the analysis and characterization of grains and voids in cemented materials were developed using toolbox functions of a mathematical software package. Utilization of grayscale, color and watershed segmentation algorithms and their performances were demonstrated on artificially prepared self-compacting concrete (SCC) samples. It has been found that color segmentation was more advantageous over the gray scale segmentation for the detection of voids whereas the latter method provided satisfying results for the aggregate grains due to the sharp contrast between their colors and the cohesive matrix. The watershed segmentation method, on the other hand, appeared to be very efficient while separating touching objects in digital images.

• Proceedings of the Korean Association of Geographic Inforamtion Studies Conference
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• 2003.04a
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• pp.145-150
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• 2003

고해상도 위성영상을 이용한 산림의 분석은 기존의 중ㆍ저해상도 영상의 분석과 다른 접근이 필요하다. 본 연구는 임분 특성을 해석하는데 중요한 판독기준인 texture를 이용하여 영상 안에서 임상, 임목직경급, 수관울폐도 등에 따른 Texture 정보를 비교 분석하고자 한다. 울산 일부 산림지역을 대상으로 3개의 가시광선 밴드와 1개의 근적외선 밴드의 1m IKONOS 영상을 이용하여 Texture 정보를 추출하는데 일반적으로 사용되는 통계적인 방법 중에 하나인 GLCM(Gray-Level Co-occurrence matrix)을 통해 Texture 분석을 하였다. 또한 1996년도에 제작된 4차 임상도를 통해 추출된 산림 특성별 Texture 정보를 비교 검토하여 고해상도 위성영상을 활용하여 산림 특성을 해석하는데 최적의 Texture 정보를 제시하고자 하였다. 고해상도 영상에서 나타나는 임분의 특성별 질감정보는 임상, 직경, 임목밀도에 따라 다양하게 나타났다.