• 디지털융복합연구
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• 제13권2호
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• pp.135-140
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• 2015

일반적인 CHMM 어휘 인식 시스템은 어휘 인식에 대한 모델들의 관측 확률 인식률이 낮고, 일부 단위 음소 모델에만 적용되어 제한적으로 사용되는 문제점이 있다. 또한, 어휘 탐색에서 어휘의 의미가 다양하여 탐색된 어휘가 사용자의 요구에 부합되지 않는 문제점을 가진다. 이러한 문제를 개선하기 위해 GMM(Gaussian Mixture Model)을 이용한 음소인식을 수행하고, 개선된 k-means 알고리즘을 이용하여 어휘 특성에 따른 제한적인 탐색 문제점을 해결하였다. 성능 실험은 기존의 시스템과 비교하여 정확도와 재현율로 대변되는 효과성을 측정하였으며, 성능 실험 결과 정확도는 83%, 재현율은 67%로 나타났다.

• 제어로봇시스템학회논문지
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• 제22권1호
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• pp.1-7
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• 2016

ADAS (Advanced Driver Assistance Systems) requires not only real-time robust lane detection, both straight and curved, but also predicting upcoming steering direction by detecting the curvature of lanes. In this paper, a curvature lane detection algorithm is proposed to enhance the accuracy and detection rate based on using inverse perspective images and Gaussian Mixture Model (GMM) to segment the lanes from the background under various illumination condition. To increase the speed and accuracy of the lane detection, this paper used template matching, RANSAC and proposed post processing method. Through experiments, it is validated that the proposed algorithm can detect both straight and curved lanes as well as predicting the upcoming direction with 92.95% of detection accuracy and 50fps speed.

• 전기학회논문지
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• 제65권3호
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• pp.477-486
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• 2016

This paper presents the area classification, identification, and tracking for multiple moving objects with the similar colors. To do this, first, we use the GMM(Gaussian Mixture Model)-based background modeling method to detect the moving objects. Second, we propose the use of the binary and morphology of image in order to eliminate the shadow and noise in case of detection of the moving object. Third, we recognize ROI(region of interest) of the moving object through labeling method. And, we propose the area classification method to remove the background from the detected moving objects and the novel method for identifying the classified moving area. Also, we propose the method for tracking the identified moving object using Kalman filter. To the end, we propose the effective tracking method when detecting the multiple objects with the similar colors. Finally, we demonstrate the feasibility and applicability of the proposed algorithms through some experiments.

• KIEAE Journal
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• 제6권2호
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• pp.51-57
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• 2006

With people's awareness of environment-friendly buildings recently increasing, there is a need to develop environment-friendly construction materials to reduce indoorair pollution levels. Thus, efforts to develop loess finishing materials that can replace the finishing materials currently being used (e.g., gypsum boards and chemical products) are underway. An analysis of the characteristics of domestic loess products,however, revealed that the cracks on loess products can be lessened and their strength can be improved by adding chemical ingredients to them. Thus, this research sought to use 100% natural materials and to develop loess finishing materials. In the experiments that were conducted in this study, appropriate mixture ratios of loess and sand/silica sand were found, and cracks and contraction ratio changes in samples were analyzed by differentiating the ratios of natural ingredients, such as lime, fine jute threads, gypsum, and jute cuttings. Loess'particle size distribution was found to have a high correlation with loess decoration, and it was discovered that the mixture of lime and fine chute threads could improve the contraction ratio. Through this study, which made use of natural ingredients, environment-friendly construction materials that can exercise the original function of loess were developed.

• Geomechanics and Engineering
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• 제1권1호
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• pp.1-15
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• 2009

Many aspects of the behavior of sands are affected by the content of non-plastic fine particles and these various aspects should be included in a constitutive model for the soil behavior. The fines content affects maximum and minimum void ratios, compressibility, shear strength, and static liquefaction under undrained conditions. Twenty-eight undrained triaxial compression tests were performed on mixtures of sand and fine particles with fines contents of 0, 10, 20, 30, 50, 75, and 100% to study the effects of fines on void ratio, compressibility, and the occurrence of static liquefaction. The experiments were performed at low consolidation pressures at which liquefaction may occur in near-surface, natural deposits. The presence of fines creates a particle structure in the soil that is highly compressible, enhancing the potential for liquefaction, and the fines also alter the basic stress-strain and volume change behavior, which should be modeled to predict the occurrence of static liquefaction in the field. The void ratio at which liquefaction occurs for each sand/fines mixture was determined, and the variation of compressibility with void ratio was determined for each mixture. This allowed a relation to be determined between fines content, void ratio, compressibility, and the occurrence of static liquefaction. Such relations may vary from sand to sand, but the present results are believed to indicate the trend in such relations.

• 산업경영시스템학회지
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• 제33권1호
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• pp.1-9
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• 2010

Quality design methodologies have received constituent attention from a number of researchers and practitioners for more than twenty years. Specially, the quality design for drug products must be carefully considered because of the hazards involved in the pharmaceutical industry. Conventional pharmaceutical formulation design problems with mixture experiments have been typically studied under the assumption of an unconstrained experimental region with a single quality characteristic. However, real-world pharmaceutical industrial situations have many physical limitations. We are often faced with multiple quality characteristics with constrained experimental regions. ln order to address these issues, the main objective of this paper is to propose a robust desirability function (RDF) model using a desirability function (DF) and mean square error (MSE) to simultaneously consider a number of multiple quality characteristics. This paper then present L-pseudocomponents and U-pseudocomponents to handle physical constraints. Finally, a numerical example shows that the proposed RDF can efficiently be applied to a pharmaceutical process design.

• 한국전자통신학회논문지
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• 제8권11호
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• pp.1647-1654
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• 2013

실외 도로에서의 차량 검출 성능은 기상 상태, 태양 이동에 의한 그림자, 조도 변화 등에 영향을 받는다. 본 논문에서는 낮 시간대의 실외도로에서 이러한 주변 환경변화에 강건한 배경 추정 알고리즘과 연동한 차량 검출 시스템을 제안한다. 배경 추정 알고리즘은 혼합 가우시안 모델을 적용하고 후보 영역에 대한 차량 검출은 Adaboost 알고리즘을 적용하였다. 흐린 날, 비오는 날 등 동일한 실제 도로에서 서로 다른 기후에 획득한 CCTV 비디오 영상을 사용한 실험을 통해 제안하는 방법이 일반 도로에서의 차량 검출에 유용한 것을 확인하였다.

• 한국연소학회지
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• 제17권4호
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• pp.5-10
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• 2012

The reformer system is a chemical device that drives the conversion of hydrocarbon to hydrogen rich gas under high temperature environment($600-1,000^{\circ}C$). Generally, NG(Natural Gas) or AOG(Anode Off Gas) is used as fuel of fuel cell reformer combustion system. The experimental study to analyze the combustion characteristics of a premixed ceramic burner used for 0.5-1.0 kW fuel cell reformer was performed. Ceramic burner experiments using NG and AOG were carried out to investigate the flame stability characteristics by heating capacity, equivalence ratio and different fuels respectively. The results show that surface flames can be classified into green, red, blue and lift-off flames as the equivalence ratio of methane-air mixture decreases. And the stable flames can be established using NG and AOG as reformer fuel in the perforated ceramic burner. In particular, the blue flame is found to be stable at a lean equivalence ratio under different mixture conditions of NG and AOG for the 0.5 to 1.0 kW fuel cell system power range. NOx emission is under 60 ppm between 0.70 to 0.78 of equivalence ratio and CO emission is under 50 ppm between 0.70 to 0.84 of equivalence ratio.

• 한국연소학회지
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• 제22권1호
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• pp.8-13
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• 2017

Ignition delay time of methane/oxygen mixture is measured experimentally with the shock tube in order to obtain the data for high pressure conditions where gas turbines and internal combustion engines are operating. The shock tube experiment is validated first over the temperature range of 1400-2000 K at 10 bar and with the various equivalence ratios of 0.5, 1 and 2. The measured ignition delays are compared with the data from the literatures. And then, experiments are conducted for non-explored conditions, i.e., at 40 bar and with the equivalence ratio of 1.5. The present experimental data show a good agreement with the available ones from the literatures and reasonable dependence on pressure and equivalence ratio. In addition, the effects of the temperature and equivalence ratio on ignition delay time are analyzed.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2007년도 하계학술대회 논문집 Vol.8
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• pp.227-228
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• 2007

Although many studies have been carried out about binary gas mixtures with $SF_6$, few studies were presented about breakdown characteristics of $SF_6/CF_4$ mixtures. At present study the breakdown characteristics of SFJCF4 mixtures in uniform field was performed. The experiments were carried out under AC and standard lightning impulse (SLI) voltages. The sphere-sphere electrode whose gap distance was 1 mm was used in a test chamber. $SF_6/CF_4$ mixtures contained from 0 to 100% $SF_6$ and the experimental gas pressure ranged from 0.1 to 0.4 MPa. The results show that addition of $SF_6$ to $CF_4$ increase AC and SLI breakdown voltages. Under AC voltages the breakdown voltages of each mixture were linearly increased according to the quantity of $SF_6$. However under SLI voltages the breakdown voltages of each mixture were similar.