• 대한음성학회:학술대회논문집
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• 대한음성학회 2003년도 5월 학술대회지
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• pp.123-126
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• 2003

We discuss how to reduce the number of inverse matrix and its dimensions requested in MLLR framework for speaker adaptation. To find a smaller set of variables with less redundancy, we employ PCA(principal component analysis) and ICA(independent component analysis) that would give as good a representation as possible. The amount of additional computation when PCA or ICA is applied is as small as it can be disregarded. The dimension of HMM parameters is reduced to about 1/3 ~ 2/7 dimensions of SI(speaker independent) model parameter with which speech recognition system represents word recognition rate as much as ordinary MLLR framework. If dimension of SI model parameter is n, the amount of computation of inverse matrix in MLLR is proportioned to O($n^4$). So, compared with ordinary MLLR, the amount of total computation requested in speaker adaptation is reduced to about 1/80~1/150.

• 제어로봇시스템학회논문지
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• 제8권11호
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• pp.976-983
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• 2002

We presents a modified variable dimension filter with input estimation for maneuvering target tracking. The conventional variable dimension filter with input estimation(VDIE) consists of the input estimation(IE) technique and the variable dimension(VD) filter. In the VDIE, the IE technique is used for estimation of a maneuver onset time and its magnitude in the least square sense. The detection of the maneuver is declared according to the estimated magnitude of the maneuver. The VD filter structure is applied for the adaptation to the maneuver of the target after compensating the filter parameter with respect to the estimated maneuver when the detection of the maneuver is declared. The VDIE is known as one of the best maneuvering target tracking filter based on a single filter. However, it requires too much computational burden since the IE technique is performed at every sampling instance and thus it is computationally inefficient. We propose another variable dimension filter with input estimation named 'Modified VDIE' which combines VD filter with If technique. Modified VDIE has less computational load than the original one by separating maneuver detection and input estimation. Simulation results show that the proposed VDIE is more efficient and outperforms in terms of computational load.

• 설비공학논문집
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• 제17권7호
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• pp.611-619
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• 2005

In a previous work of the authors, the heat and mass transfer in a desiccant rotor was analyzed theoretically through linearization assumptions and four dimensionless parameter groups dominating the dehumidification process were arranged. In this work is verified whether the four dimensionless parameters also play the dominant roles in more realistic situations where the nonlinear factors affect the heat and mass transfer. The results show that the dehumidification characteristics are closely similar to each other as long as the four dimensionless parameters have the same set of values while the rotor configurations and/or the operation conditions are different from each other. The four dimensionless parameters are $\Psi,\;\chi,\;\sigma$ and N, where $\Psi$ implies the average gradient of relative humidity lines in the psychrometric chart, $\chi$ the heat capacity of the rotor and $\sigma$ the sorption capacity of the rotor, and N implies the number of transfer unit.

• 융합신호처리학회 학술대회논문집
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• 한국신호처리시스템학회 2000년도 추계종합학술대회논문집
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• pp.181-184
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• 2000

본 논문에서는 음성 특징추출의 한 방법으로서 기존의 방법들과는 달리 음성의 통계적인 특성들을 고려하여, 입력 공간내에서 변동량이 가장 많은 방향으로 주축을 발견한 다음 그 정보를 이용하여 데이터의 중복성을 제거하는 주성분 해석(PCA:Principal Component Analysis)기법을 사용하여 음성의 특징을 추출하는 방법을 제안한다. 본 논문의 숫자음 인식실험 결과와 비교하기 위하여 기존의 음성특징 파라메타인 Mel-Cepstrum과 비교하였을 때, 0.5%의 인식률 차이가 있었으나, 음성특징 추출시 기존의 파라메타에 비하여 비교적 짧은 시간에 구해지는 점과 데이터의 통계적 특성을 이용한 최적의 기저벡터를 이용한다면 단어나 문장 인식시에 보다 나은 인식률을 얻으리라 사료된다.

• 한국대기환경학회지
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• 제16권5호
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• pp.539-544
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• 2000

A simple analytic model is proposed here to analyze the concentration deficit field caused by a large area of vegetated area. With non-dimensional deposition velocity chosen as small parameter, the regular perturbation method is exploited to derive the mass balance equation and the dynamic equations for the concentration deficit field, Analytic solutions to those equations are obtained in a closed form for several cases of interest, assuming that the concentration field is stationary and the plume can be nicely approximated as Gaussian for a point source. The results suggest that quite a negligible fraction (less than 1%) of the gaseous air pollutants emitted into the air is removed by the vegetated area of which width is 4 km in wind-wise direction, the typical dimension of the Restricted Development Zones around the metropolitan regions in South Korea.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2007년도 Proceedings of ISRS 2007
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• pp.247-249
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• 2007

Crown parameters are important roles in tree species identification, because the canopy is the aggregate of all the crowns. However, crown measurements with spaceborne image data have remained more difficult than on aerial photographs since trees show more structural detail at higher resolutions. This recognized problem led to the initiation of the research to determine if high resolution satellite image data could be used to identify and classify single tree species. In this paper, shape parameters derived from pixel-based crown area measurements and texture features derived from GLCM parameters in QuickBird image were tested and compared for individual tree species identification. As expected, initial studies have shown that the crown parameters and the canopy texture parameters provided a differentiating method between coniferous trees and broad-leaved trees within the compartment(less than forest stand) for single extraction from spaceborne high resolution image.

• 한국레이저가공학회지
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• 제2권2호
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• pp.8-17
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• 1999

This study includes a basic feature of laser surface alloying for enhancing the surface properties of materials. Effects of laser processing parameters such as beam power, beam size, scanning speed on the shape and composition of alloyed layer was simulated in case of moving beam conditions (2-dimensional numerical methods). Simulated results were compared with experiments, in which the plasma coating of 80% Ni ＋ 20% Cr deposited on the SS41 substrate was remelted with CO2 laser with Gaussian energy distribution. Simulation and experiments revealed that the shape (dimension)and composition of laser alloyed layer were strongly dependent upon the process parameters, especially interaction time (travel speed) as compared to beam diameter, beam power and absorptivity. The shape and composition of alloyed layervaried more or less exponentially with parameters.

• Transactions on Electrical and Electronic Materials
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• 제9권1호
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• pp.16-19
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• 2008

In this study, it was investigated about optical simulation in direct-type backlight design. Direct-type backlight has been used high-brightness backlight such as medical LCD application. The key parameter in designing direct-type backlight was consists of three geometrical dimension such as the distance of two lamps, the gap of lamp and reflection plate and the number of lamps. It has many of variations in optical design and it causes the different properties in backlight system. It shows the best values of above parameters; 26 mm of the distance of two lamps, 4.5 mm of the gap of lamp and reflection plate and 16 lamps. And we produced the specimen as above condition, and acquired good result in backlight such as the value of the brightness is 6423 nit in center of emission area and less than 5 % in brightness uniformity. It shows the effective ways of designing backlight system using optical simulation method for medical LCD application.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2007년도 하계학술대회 논문집 Vol.8
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• pp.415-415
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• 2007

In this study. it was investigated about optical simulation in direct-type backlight design. Direct-type backlight has been used high-brightness backlight such as LCD television application. The key parameter in designing direct-type backlight was consists of three geometrical dimension such as the distance of two lamps. the gap of lamp and reflection plate and the number of lamps. It has many variation in optical design and it causes the different properties in backlight system. It shows the best values of above parameters; 26mm of the distance of two lamps. 4.5mm of the gap of lamp and reflection plate and 16 lamps. And we produced the specimen as above condition. and acquired good result in backlight such as the value of the brightness is 6436 nit in center of emission area and less than 5% in brightness uniformity. It shows the effective ways of designing backlight system using optical simulation method.

• Geomechanics and Engineering
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• 제21권3호
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• pp.289-300
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• 2020

Estimating the damage induced by an explosion around a blast hole has always been a challenging issue in geotechnical engineering. It is difficult to determine an exact dimension for damage zone since many parameters are involved in the formation of failures, and there are some uncertainties lying in these parameters. Thus, the present study adopted a probabilistic approach towards this problem. First, a reliability model of the problem was established and the failure probability of induced damage was calculated. Then, the corresponding exceedance risk curve was developed indicating the relation between the failure probability and the cracked zone radius. The obtained risk curve indicated that the failure probability drops dramatically by increasing the cracked zone radius so that the probability of exceedance for any crack length greater than 4.5 m is less than 5%. Moreover, the effect of each parameter involved in the probability of failure, including blast hole radius, explosive density, detonation velocity, and tensile strength of the rock, was evaluated by using a sensitivity analysis. Finally, the impact of the decoupling ratio on the reduction of failures was investigated and the location of its maximum influence was demonstrated around the blast point.