• Phonetics and Speech Sciences
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• v.7 no.1
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• pp.3-10
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• 2015

In this paper, different frequency scales in cepstral feature extraction are evaluated for the text-independent speaker recognition. To this end, mel-frequency cepstral coefficients (MFCCs), linear frequency cepstral coefficients (LFCCs), and bilinear warped frequency cepstral coefficients (BWFCCs) are applied to the speaker recognition experiment. In addition, the spectro-temporal features extracted by the cepstral-time matrix (CTM) are examined as an alternative to the delta and delta-delta features. Experiments on the NIST speaker recognition evaluation (SRE) 2004 task are carried out using the Gaussian mixture model-universal background model (GMM-UBM) method and the joint factor analysis (JFA) method, both based on the ALIZE 3.0 toolkit. Experimental results using both the methods show that BWFCC with appropriate warping factor yields better performance than MFCC and LFCC. It is also shown that the feature set including the spectro-temporal information based on the CTM outperforms the conventional feature set including the delta and delta-delta features.

• Journal of the Korean Institute of Telematics and Electronics
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• v.27 no.10
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• pp.53-59
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• 1990

In the control of robot manipulators, this paper presents a design of a new variable structure model following controller(VSMFC) using computed torque method (CTM). A sufficient condition for the existence of a sliding mode is derived by Lyapunov function. The reference model is a double integrators and the acceleration input consists of a proportional-derivative controller for the purpose of the stabilization of system and the desired performance. The proposed control scheme which consists of upper bounded and estimated value of each term of the manipulator of matrix inversion. Therefore the simulation results show that this controller is improved to the convergence of desired trajectories.

• Journal of Korean Society of Transportation
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• v.20 no.5
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• pp.193-206
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• 2002

A signal optimization model is proposed by applying the Cell-Transmission Model(CTM) as an embedded traffic flow model to estimate a system-optimal signal timing plan in a transportation network composed of signalized intersections. Beyond the existing signal-optimization models, the CTM provides appropriate theoretical and practical backgrounds to simulate oversaturation phenomena such as shockwave, queue length, and spillback. The model is formulated on the Mixed-Integer Programming(MIP) theory. The proposed model implies a system-optimal in a sense that traffic demand and signal system cooperate to minimize the traffic network cost: the demand departing from origins through route choice behavior until arriving at destinations and the signal system by calculating optimal signal timings considering the movement of these demand. The potential of model's practical application is demonstrated through a comparison study of two signal control strategies: optimal and fixed signal controls.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.12
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• pp.2202-2207
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• 2007

The present article investigates experimentally and theoretically thermal and optical characteristics of thin film structures through measurement of thermal conductivity of Pyrex 7740 and reflectance in silicon thin film. The $3{\omega}$ method is used to measure thermal conductivity of very thin film with high accuracy and the optical characteristics in thin films are studied to examine the influence of incidence angle of light on reflectance by using the CTM(Characteristics Transmission Method) and the 633 nm He-Ne laser reflectance measurement system. It is found that the estimated reflectance of silicon show good agreement with experimental data. In particular, the present study solves the EPRT(Equation of Phonon Radiative Transport) which is based on Boltzmann transport equation for predicting thermal conductivity of nanoscale film structures. From the results, the measured thermal conductivity is in good agreement with the previous published data. Moreover, thermal conductivities are estimated for different film thickness. It indicates that as film thickness decreases, thermal conductivity decreases substantially due to internal scattering.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.11
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• pp.5530-5546
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• 2016

Automatic analysis and understanding of human activities is a challenging task in computer vision, especially for the surveillance scenarios which typically contains crowds, complex motions and occlusions. To address these issues, a Bag-of-words representation of videos is developed by leveraging information including crowd positions, motion directions and velocities. We infer the crowd activity in a motion field using Category Constrained Correlated Topic Model (CC-CTM) with latent topics. We represent each video by a mixture of learned motion patterns, and predict the associated activity by training a SVM classifier. The experiment dataset we constructed are from Crowd_PETS09 bench dataset and UCF_Crowds dataset, including 2000 documents. Experimental results demonstrate that accuracy reaches 90%, and the proposed approach outperforms the state-of-the-arts by a large margin.

• International Journal of Naval Architecture and Ocean Engineering
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• v.6 no.1
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• pp.151-161
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• 2014

In this study, an experimental investigation has been made of the applicability of outer-layer vertical blades to real ship model. After first devised by Hutchins and Choi (2003), the outer-layer vertical blades demonstrated its effectiveness in reducing total drag of flat plate (Park et al., 2011) with maximum drag reduction of 9.6%. With a view to assessing the effect in the flow around a ship, the arrays of outer-layer vertical blades have been installed onto the side bottom and flat bottom of a 300k KVLCC model. A series of towing tank test has been carried out to investigate resistance (CTM) reduction efficiency and improvement of stern wake distribution with varying geometric parameters of the blades array. The installation of vertical blades led to the CTM reduction of 2.15~2.76% near the service speed. The nominal wake fraction was affected marginally by the blades array and the axial velocity distribution tended to be more uniform by the blades array.

• Journal of the Korean Society of Visualization
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• v.16 no.3
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• pp.26-34
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• 2018

In the present study, an experimental assessment has been made of the drag reducing efficiency of the outer-layer vertical blades, which were first devised by Hutchins(1). A detailed flow field measurements have been performed using 2-D time resolved PIV with a view to enabling the identification of drag reduction mechanism. In addition, an experimental investigation has been made of the applicability of outer-layer vertical blades to real ship model. The arrays of outer-layer vertical blades have been installed onto the flat side and flat bottom of a 300k KVLCC model. A series of towing tank test has been carried out to investigate resistance (CTM) reduction efficiency with various geometric parameters and installed places of blades. The installation of vertical blades led to the CTM reduction of 1.44~3.17% near the service speed.

• Journal of Korean Neurosurgical Society
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• v.30 no.8
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• pp.1042-1046
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• 2001

The incidence of paraplegia following drain of cerebrospinal fluid(CSF) by lumbar puncure below a spinal block is rare, and most of them occurred in spinal tumor. We report a case of acute paraplegia following lumbar puncture for computed tomography myelography(CTM) in a 42-year-old man who sustained a cervical disc herniation. Four hours after lumbar puncture for CTM, sudden paraplegia was developed. After emergent anterior cervical discectomy and fusion with cervical plating, the patient recovered completely. To the authors' knowledge, this is the first case of spinal shock complicating lumbar puncture for routine myelography in a patient with cervical disc herniation. The prompt recognition of this unusual complication of lumbar puncture may lead to good clinical outcome. Instead of CTM requiring lumbar puncture, MRI should be considered as the initial diagnostic procedure in a patient of cervical disc herniation associated with myelopathy. We discuss the possible mechanisms of acute paraplegia following lumbar puncture with literature review.

• Current Photovoltaic Research
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• v.7 no.4
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• pp.111-120
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• 2019

The output power of a crystalline silicon (c-Si) photovoltaic (PV) module is not directly the sum of the powers of its unit cells. There are several losses and gain mechanisms that reduce the total output power when solar cells are encapsulated into solar modules. Theses factors are getting high attention as the high cell efficiency achievement become more complex and expensive. More research works are involved to minimize the "cell-to-module" (CTM) loss. Our paper is aimed to focus on electrical losses due to interconnection and mismatch loss at PV modules. Research study shows that among all reasons of PV module failure 40.7% fails at interconnection. The mismatch loss in modern PV modules is very low (nearly 0.1%) but still lacks in the approach that determines all the contributing factors in mismatch loss. This review paper is related to study of interconnection loss technologies and key factors contributing to mismatch loss during module fabrication. Also, the improved interconnection technologies, understanding the approaches to mitigate the mismatch loss factors are precisely described here. This research study will give the approach of mitigating the loss and enable improvement in reliability of PV modules.

• Journal of the Korean Applied Science and Technology
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• v.32 no.3
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• pp.461-468
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• 2015

Simultanious quantitative determination of Cetyltrimetyl ammonium chloride(CTM), Stearamidopropyl dimetylamine(SAP), Behentriammonium chloride(BHT), Dihexadeyldimethyl ammonium chloride(DHDDM) was carried out by reversed phase HPLC. The 0.2% TFA/Methanol was used for the mobile phase of gradient conditions. An Alltech $C_{18}$($250mm{\times}4.6mm$ i.d., $5{\mu}m$)and the selected ELSD detector was applied. The analysis results of HPLC showed good linearity with correlation coefficient of $r^2=0.997$ in the rage of $130{\sim}1980.5{\mu}g/mL$ and detection limit.