• Proceedings of the Acoustical Society of Korea Conference
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• autumn
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• pp.131-134
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• 2004

본 논문에서는 GMM(Gaussian Mixture Model)을 이용한 문맥독립 화자 검증 시스템을 구현한 후, arctan 함수를 이용한 정규화 방법을 사용하여 화자검증실험을 수행하였다. 특징파라미터로서는 선형예측방법을 이용한 켑스트럼 계수와 회귀계수를 사용하고 화자의 발성 변이를 고려하여 CMN(Cepstral Mean Normalization)을 적용하였다. 화자모델 생성을 위한 학습단에서는 화자발성의 음향학적 특징을 잘 표현할 수 있는 GMM(Gaussian Mixture Model)을 이용하였고 화자 검증단에서는 ML(Maximum Likelihood)을 이용하여 유사도를 계산하고 기존의 정규화 방법과 arctan 함수를 이용한 방법에 의해 정규화된 점수(score)와 미리 정해진 문턱값과 비교하여 검증하였다. 화자 검증 실험결과, arctan 함수를 부가한 방법이 기존의 방법보다 항상 향상된 EER을 나타냄을 확인할 수 있었다.

• Proceedings of the Korean Geotechical Society Conference
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• 1997.03a
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• pp.161-168
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• 1997

The purpose of this study is to evaluate the possibility of normalization of the distibutions of soil parameters taken from soft ground and the reliability of the safety factors of specific objects on it, including sanitary landfill. Through this study it is found that distributions of soil parameters could be adjusted to appropriate normal distributions as possibility density functions(PDF), and that especially the group of initial cohesions and the coresponding safety factors has a perfect linear correlation. According to those results the PDF to initial cohesion as possibility parameter can not only be tmsformed to the PDF to safety factor but also, conseqently, the reliability of the safety factor(SF) simply based on the mean value of soil parameter(Co) can be calculated or easily picked up from the standrad normal distribution table. It is therefore concluded that even though calculated values of safety factors are over any standard requirements some possibility of risk both to the objects and natural soft ground could be still existing, and also a new standard value for this slope stability control system should be derived just by adjusting old one according to the magnitude of risk possibility.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.7C
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• pp.562-568
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• 2008

This paper proposes the scheme which obtain the coefficients of TDL filter and two normalization algorithms among methods which get solution of equivalent Wiener-Hopf Equation in Gram-Schmidt algorithm. Compared to the conventional NLMS algorithm, normalizes with sum of power of inputs, the presented algorithms normalize using sums of eigenvalues. Using computer simulation, we perform an system identification in an unstable environment where two poles are located in near position outside unit circle. Consequently, the proposed algorithms get the coefficients of TDL filter in Gram-Schmidt algorithm recursively and show better convergence performance than conventional NLMS algorithm.

• Journal of the Korean Institute of Telematics and Electronics
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• v.20 no.4
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• pp.47-54
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• 1983

The performance of an intra-frame DCT/DPCM hybrid coding is investigated with the criteria of normalized mean square error and subjective test for various system parameters. It includes the prediction coefficient in transform domain, normalization factor and bit-map in block quantizer, and adaptive coding. It is shown that the generalized covariance model of image is a convenient tool for bit-map and adaptive coding, and for a fast low bit-rate coding.

• Proceedings of the KOSOMBE Conference
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• v.1996 no.11
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• pp.310-313
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• 1996

In this study, we developed three dimensional FDG brain PET and MRI coregistration technique. The boundaries of the head in PET and MRI were segmented using sinogram of emission PET scan and T1-weighted MRI. We registered both boundaries by minimizing the mean Euclidean distance of those. To display the registered PET and MRI simultaneously, we used weighted normalization method and interleaving method.

• Journal of the Korean Society of Industry Convergence
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• v.23 no.6_2
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• pp.1025-1032
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• 2020

In this paper, we propose a method to classify road weather conditions into rain, fog, and sun using a SVM (Support Vector Machine) classifier after extracting weather features from images acquired in real time using an optical sensor installed on a roadside post. A multi-dimensional weather feature vector consisting of factors such as image sharpeness, image entropy, Michelson contrast, MSCN (Mean Subtraction and Contrast Normalization), dark channel prior, image colorfulness, and local binary pattern as global features of weather-related images was extracted from road images, and then a road weather classifier was created by performing machine learning on 700 sun images, 2,000 rain images, and 1,000 fog images. Finally, the classification performance was tested for 140 sun images, 510 rain images, and 240 fog images. Overall classification performance is assessed to be applicable in real road services and can be enhanced further with optimization along with year-round data collection and training.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.16 no.3
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• pp.757-770
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• 2022

Palmprint recognition has drawn increasingly attentions in the past decade due to its uniqueness and reliability. Traditional palmprint recognition methods usually use high-resolution images as the identification basis so that they can achieve relatively high precision. However, high-resolution images mean more computation cost in the recognition process, which usually cannot be guaranteed in mobile computing. Therefore, this paper proposes an improved low-resolution palmprint image recognition method based on residual networks. The main contributions include: 1) We introduce a channel attention mechanism to refactor the extracted feature maps, which can pay more attention to the informative feature maps and suppress the useless ones. 2) The ResStage group structure proposed by us divides the original residual block into three stages, and we stabilize the signal characteristics before each stage by means of BN normalization operation to enhance the feature channel. Comparison experiments are conducted on a public dataset provided by the Hong Kong Polytechnic University. Experimental results show that the proposed method achieve a rank-1 accuracy of 98.17% when tested on low-resolution images with the size of 12dpi, which outperforms all the compared methods obviously.

• Smart Structures and Systems
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• v.32 no.6
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• pp.393-402
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• 2023

Recently, hybrid and electric vehicles have been actively developed to replace internal combustion engine (ICE) vehicles. However, their vibrations and noise with complex spectra cause discomfort to drivers. To reduce the vibrations transmitted through primary excitation sources such as powertrains, structural changes have been introduced. However, the interference among different parts is a limitation. Thus, active mounting systems based on smart materials have been actively investigated to overcome these limitations. This study focuses on diminishing the source movement when a structure with two active mounting systems is excited to a single sinusoidal and a multi-frequency signal, which were investigated for source movement reduction. The overall structure was modeled based on the lumped parameter method. Active vibration control was implemented based on the modeled structure, and a multi-normalization least mean square (NLMS) algorithm was used to obtain the control input for the active mounting system. Furthermore, the performance of the NLMS algorithm was compared with that of the quantification method to demonstrate the performance of active vibration control. The results demonstrate that the vibration attenuation performance of the source component was improved.

• Journal of Korean Neurosurgical Society
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• v.45 no.3
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• pp.157-163
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• 2009

Objective : In recent years, CyberKnife has emerged as an important treatment modality in the management of pituitary adenomas. Treatment results after performing CyberKnife and the complications of this procedure are reviewed. Methods : Twenty-six patients with pituitary adenomas received stereotactic radiosurgery with the CyberKnife (CKRS). The follow-up periods ranged from 7 months to 47 months (mean$\pm$SD : $30{\pm}12.7$ months). The patients consisted of 17 with non-functioning adenomas, 3 with prolactinomas and 6 with acromegaly. The change in the tumor volume, visual acuity, hormonal function, and complications by this therapy were analyzed in each case. Results : The tumor control rate was 92.3%. Hormonal function was improved in all of the 9 (100%) functioning adenomas. Hormonal normalization was observed in 4 of the 9 (44%) patients with a mean duration of 16 months. In two patients (7.6%), visual acuity worsened due to cystic enlargement of the tumor after CKRS. No other complications were observed. Conclusion : CyberKnife is considered safe and effective in selected patients with pituitary adenomas. However, longer follow-up is required for a more complete assessment of late toxicity and treatment efficacy.

• Journal of Korean Neurosurgical Society
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• v.50 no.4
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• pp.357-362
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• 2011

Objective : To report our experience with pyogenic spondylitis treated with anterior radical debridement and insertion of a titanium mesh cage and to demonstrate the effectiveness and safety of the use of a titanium mesh cage in the surgical management of pyogenic spondylitis. Methods : We retrospectively analyzed the clinical characteristics of 19 patients who underwent surgical treatment in our department between January 2004 and December 2008. The average follow-up period was 11.16 months (range, 6-64 months). We evaluated risk factors, cultured organisms, lab data, clinical outcomes, and radiographic results. Surgical techniques for patients with pyogenic spondylitis were anterior radical debridement and reconstruction with titanium mesh cage insertion and screw fixation. All patients received intravenous antibiotics for at least 6 weeks postoperatively, and some patients received oral antibiotics. Results : The infections resolved in all of the patients as noted by normalization of their erythrocyte sedimentation rates and C-reactive protein levels. The mean pain score on a Visual Analog Scale was 7.8 (range, 4-10) before surgery and 2.4 (range, 1-5) after surgery. The Frankel grade was improved by one grade in seven patients. After surgery, the average difference of the angle was improved about $6.96^{\circ}$ in all patients. At the last follow-up, the mean loss of correction was $4.86^{\circ}$. Conclusion : Anterior radical debridement followed by the placement of instrumentation with a titanium mesh cage may be a safe and effective treatment for selected patients with pyogenic spondylitis. This surgical therapy does not lead to recurrent pyogenic spondylitis.