• Journal of Information Processing Systems
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• 제15권4호
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• pp.748-764
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• 2019

In order to deal with the filtering delay problem of least mean square adaptive filter noise reduction algorithm and music noise problem of spectral subtraction algorithm during the speech signal processing, we combine these two algorithms and propose one novel noise reduction method, showing a strong performance on par or even better than state of the art methods. We first use the least mean square algorithm to reduce the average intensity of noise, and then add spectral subtraction algorithm to reduce remaining noise again. Experiments prove that using the spectral subtraction again after the least mean square adaptive filter algorithm overcomes shortcomings which come from the former two algorithms. Also the novel method increases the signal-to-noise ratio of original speech data and improves the final noise reduction performance.

• Archives of Plastic Surgery
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• 제38권3호
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• pp.300-308
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• 2011

Purpose: The goal of reduction mammaplasty is breast with natural cone shape, minimizing scars, well-placed and sensate nipple-areolar area and maintaining breast physiology. In order to satisfy that goal, variable reduction mammaplasty methods are performed, however, two methods such as vertical reduction method and inverted T-scar method are currently most used. We compared indications and advantages of the two methods and set up useful guidlines. Methods: For 15 years from 1995 to 2010, we experienced 84 patients (162 breasts). We performed vertical reduction method as Lejour's superior pedicle technique (45 patients) and inverted T-scar method as Goldwyn's inferior dermal flap technique (39 patients). We evaluated the result of the operation comparing patient's age, amount of resected tissue, complications and post-operative scars of the two methods. Results: The mean age was 36 years and the vertical reduction group was 3 years younger than inverted T-scar group. The mean breast tissue resection amount per one breast, inverted T-scar group (712 gm) was lagger than vertical reduction group (395 gm). Conclusion: There is no ideal method for reduction mammaplasty until now. However, we suggest that guide line, the vertical reduction method is effective for minimal and moderate macromastia in young and middle aged women and inverted T-scar method is appropriate for severe macromastia with ptosis in elderly women. Recently, all procedures tried shorter and smaller scar on the vertical line as small I, J or L shape scar, and inframammary fold as short inverted T-scar.

• 전자공학회논문지B
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• 제28B권5호
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• pp.318-326
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• 1991

A Quantizer reconstruction level control method for block artifact reduction in DCT image coding is described. In our scheme, quantizer reconstruction level control is obtained by adding quantization level step size to the optimum quantization level in the direction of reducing the block artifact by minimizing the mean square error(MSE) and error difference(EDF) distribution in boundary without the other additional bits. In simulation results, although the performance in terms of signal to noise ratio is degraded by a little amount, mean square of error difference at block boundary and mean square error having relation block artifact is greatly reduced. Subjective image qualities are improved compared with other block artifact reduction method such as postprocessing by filtering and trasform coding by block overlapping. But the addition calculations of 1-dimensional DCT become to be more necessary to coding process for determining the reconstruction level.

• Wind and Structures
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• 제24권2호
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• pp.119-144
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• 2017

The traditional method for the simulation of high Reynolds number (Re) effects on wind loads on cooling tower models in wind tunnels focuses only on the mean wind pressure distribution. Based on observed effects of some key factors on static/dynamic flow characteristics around cooling towers, the study reported in this paper describes a comprehensive simulation method using both mean and fluctuating wind pressure distributions at high Re as simulation targets, which is indispensable for obtaining the complete full-scale wind effects in wind tunnels. After being presented in this paper using a case study, the proposed method is examined by comparing the full covariance matrices and the cross-spectral densities of the simulated cases with those of the full-scale case. Besides, the cooling tower's dynamic structural responses obtained using the simulated wind pressure fields are compared with those obtained by using the full-scale one. Through these works, the applicability and superiority of the proposed method is validated.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2001년도 추계학술대회 논문집
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• pp.162-165
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• 2001

In industrial practice, caliber design in shape rolling depends on the designer's experience, which in general is obtained through costly trial-and error process. on-line model which is relations of mean effective strain, roll force and area reduction is derived from finite element process simultion in bar rolling with three rolls.

• 오토저널
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• 제13권6호
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• pp.90-100
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• 1991

This paper represents the analysis of the sheet drawing by applying the Matrix method to Hill's slip-line field for small reduction and indirect type slip-line field in case of large reduction. Results of the analysis represent the relation between the reduction ratio and the die wall pressure, mean drawing stress through rough die. The limitation on the use of this slip-line field is described. When the reduction ratio is given, the optimum die angle is analyzed in this paper.

• Communications for Statistical Applications and Methods
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• 제19권1호
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• pp.107-115
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• 2012

본 논문에서는 Yoo와 Cook (2007)에 의하여 제시된 다변량 회귀의 조건부 평균에 대한 최소 불일치 함수 접근법을 통한 최적 차원축소 부분공간의 추정에서 차원의 수가 추정된 선형결합들과 설명력 등에 어떤 영향을 미치는 지를 시뮬레이션 자료를 통하여 알아보았다. 그 결과 추정에 사용된 차원수에 따른 여러 결과들을 차원결정을 위한 검정과 함께 활용하면 모형에 필요한 차원수를 탐색하는데 매우 효과적임을 알 수 있었다.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제34권1호
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• pp.53-57
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• 2012

Purpose: This study considered the effects and proper treatments of mandibular condyle fractures by comparing clinical differences and complications according to analysis and treatment plan. Methods: From September 2007 to August 2010, patients who were diagnosed with condylar fracture and monitored for more than 3 months were selected. Cases were divided in a reductive manner and evaluated by type and period of intermaxillary fixation (IMF), status of occlusion and trismus according to the Spiessle/Schroll method. A total 50 patients were examined. Results: The number of the unilateral condyle fractures was 45 and 30 patients had multiple fractures. Type of fracture was categorized by the Spiessle/Schroll method. There were 21 patients with type I, 11 patients with type II, 3 patients with type 3, 10 patients with type V and 5 patients with type VI; there were no patients with a type IV fracture. 11 patients were operated on with open reduction. Among them, 9 patients were type II and 2 patients were type I. For type I patients, an intra-oral approach was conducted with an endoscope and trocar. For 3 of the type II patients, an retromandibular approach was conducted and for the rest of the type II patients, the same approach as type I was used. The periods of IMF were 2.36 weeks (mean) in open reduction group and 2.9 weeks (mean) in closed reduction group and the total mean period is 2.78 weeks. All patients had stable occlusion after removing the IMF. Trismus occurred in 1 patient for open reduction and 5 patients for closed reduction. Facial nerve palsy was observed in one patient postoperatively that resolved after 6 months. Conclusion: In this study, similar prognosis was shown after an open and closed reduction was conducted. Therefore, treatments need to be planned depending on the degree of condyle fracture and the amount of displacement. Additionally, the period of IMF could be shortened with open reduction.

• 한국생활과학회지
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• 제17권5호
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• pp.963-973
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• 2008

Clothing pressure is closely connected with the degree of comfort of an athlete's tight-fitting garments. Therefore, the construction of sports garments is very important to the wearer's athletic performance. In this study, the fundamental relationship between the reduction rates of stretch fabrics and clothing pressure was explored with the aim of improving clothing comfort and obtaining a systematic pattern reduction for women's tight-fitting bodysuits. A women's bodysuit pattern was obtained by the draping method using a dressform. The basic pattern was divided into four parts and changed into reduced pattems according to the amount of fabric stretch determined by ASTM D2594. Clothing pressure was measured using an air-pack-type pressure sensor (model AMI 3037-2) at 20 locations (shoulder, 9 locations; bust, 5; and armhole, 6). Among the 15 garments tested, the mean pressure of the A1 bodysuit was 4.60 $gf/cm^2$, and that of the C5 bodysuit was 22.98 $gf/cm^2$. The mean pressures of the bodysuits with reduction rates of 10% and 20% were below 10 $gf/cm^2$, while those of suits with reduction rates of 30%,40%, and 50% (except C5) were below 20 $gf/cm^2$. The pressure at the shoulder was 9.50$\sim$32.24 $gf/cm^2$, which was higher than that at the bust (3.34$\sim$24.56 $gf/cm^2$) and the armhole (0.95$\sim$12.15 $gf/cm^2$). The mean pressures of the 15 bodysuits were divided into five groups using analysis of variance (ANOVA), and were found to be significantly different (p<0.001). Regression analysis afforded the following expression: mean pressure ($gf/cm^2$) = 1.607 + 0.369[reduction rate (%)].

• 대한전자공학회논문지
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• 제12권3호
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• pp.30-36
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• 1975

TDM 회선을증가하기 위한 두가지 방식-주기적 sample skipping방법과 표본화주파수 축소 방법-에 대한 불특성을 해석비교하였다. 신호는 통계적으로 stationary인 random신호로 가정했으며, 선로의 잡음과 각랑 상호 간의 간섭효과는 고려하지 않았다. 음성신호에 대한 구체적 비교 결과, 주기회 sample skipping방법이 실제적 설계조건에서 훌륭한 선택이 될 수 있음을 보였다. Distortions are analyzed and compared for two TDM channel expansion methods- periodic sample skipping and sampling frequency reduction. Signal is assumed to be stationary random signal with zero·mean. Channel noise and interference are not considered in the analysis. For speech signal, it is shown that the periodic sample skipping method could be a better choice under practical design constraints.