• KSII Transactions on Internet and Information Systems (TIIS)
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• v.15 no.9
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• pp.3186-3203
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• 2021

In this paper, a multi-scale local difference directional number (MLDDN) pattern is proposed for pig identification. Firstly, the color images of individual pig are converted into grey images by the most significant bits (MSB) quantization, which makes the grey values have better discrimination. Then, Gabor amplitude and phase responses on different scales are obtained by convoluting the grey images with Gabor masks. Next, by calculating the main difference of local edge directions instead of traditionally edge information, the directional numbers of Gabor amplitude and phase responses are encoded. Finally, the block histograms of the encoded images are concatenated on each scale, and the maximum pooling is adopted on different scales to avoid the high feature dimension. Experimental results on two pigsties show that MLDDN impressively outperforms the other widely used local descriptors.

• Proceedings of the KIEE Conference
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• 2001.11b
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• pp.124-126
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• 2001

A reliable fault type identification (phase selection) plays a very important role in transmission line protection, particularly in Extra High Voltage(EHV) networks. The conventional fault type identification algorithm used the phase difference between positive and negative sequence current excluding load current. But, it is difficult to pick out only fault current since we can not know when a fault occurs and identify the fault type in weak-infeed conditions that dominate zero-sequence current in phase current. The proposed algorithm can identify the accurately fault type using the sum of unit vectors which are calculated by positive-sequence votage and negative-sequence voltage.

• Journal of the Society of Naval Architects of Korea
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• v.57 no.3
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• pp.160-167
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• 2020

A two-stroke diesel engine and a propeller normally adopted in large merchant ships are regarded as major ship vibration sources. They are directly connected and generate various excitation components proportional to the rotating speed of diesel engine. Among the components, the magnitude of two excitation components with the same frequency generated by both engine and propeller can be compensated by the adjustment of their phase difference. It can be done by the optimization of propeller assembly angle but requires a number of burdensome trials to find the optimal angle. In this paper, the efficient estimation method to determine optimal propeller assembly angle is proposed. Its application requires the axial vibration measurement in sea trial and the numerical vibration analysis for propulsion shafting which can be substituted by additional vibration measurement after one-trial modification of propeller assembly angle. In order to verify the validity of the proposed method, the phase difference between two fifth order excitation components generated by both diesel engine and propeller of a real ship is calculated by the finite element analysis and its result is indirectly validated by the comparison of axial vibration responses at intermediate shaft obtained by the numerical analysis and the measurement in sea trial. Finally, it is numerically confirmed that axial vibration response at intermediate shaft at a resonant speed can be decreased more than 87 % if the optimal propeller assembly angle determined by the proposed method is applied.

• Journal of KSNVE
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• v.6 no.6
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• pp.835-842
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• 1996

To identify the locations and strengths of acoustic sources, one may use a microphone line array. Apparent advantage of the source identification method utilizing a line array is that it requires less measurement points than intensity method and holography. This method is based on the information of magnitude and phase difference between pressure signals at each microphone. Since those differences are dependent on the source model, we have to assume them such as plane, monopole, etc. In this paper the conventional source identification methods such as beamforming method and MUSIC method are briefly reviewed by modeling a source as plane and spherical wave, then a modified method is introduced. This can be applied to sound field which may by either coherent or incoherent. Typical simulations and experiment are performed to confirm this identification method.

• The Journal of the Acoustical Society of Korea
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• v.26 no.6
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• pp.243-249
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• 2007

We propose an effective voice-based gender identification using group delay(GD) Generally, features for speech recognition are composed of magnitude information rather than phase information. In our approach, we address a difference between male and female for GD which is a derivative of the Fourier transform phase. Also, we propose a novel way to incorporate the features fusion scheme based on a combination of GD and magnitude information such as mel-frequency cepstral coefficients(MFCC), linear predictive coding (LPC) coefficients, reflection coefficients and formant. The experimental results indicate that GD is effective in discriminating gender and the performance is significantly improved when the proposed feature fusion technique is applied.

• Proceedings of the KIEE Conference
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• 1993.11a
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• pp.139-141
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• 1993

A new scheme to measure the rotor time constant and to set the slip gain of a vector-controller is presented. The approach utilizes the phase difference between the torque producing component of the stator current and rotor current in the stationary frame. It is shown that the rotor time constant can be uniquely identified by detecting the corresponding phase difference. The simulation was carried out by considering the variation of other parameters and the torque producing component of the stator current frequency.

• Korean Journal of Construction Engineering and Management
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• v.21 no.2
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• pp.70-78
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• 2020

Construction program management requires more systematic management than traditional management methods due to the complexity of the project and various stakeholders. In particular, the systematization of closure phase of the process is in urgent need as there is a difference between the owner's expectations and the contractor's deliverables, resulting in delayed handovers, conflicts, frictions, and increased legal disputes. This study identified the process and activities of closure phase through domestic and international literature and case studies for the successful closure of the construction program. Further, the proposed processes and activities were verified through expert verification for appropriateness and the possibility of application to the site. By utilizing the processes and activities proposed in this study, the project aims to overcome the limits of closure phase and improve the satisfaction of the owner, as well as to enhance the global competitiveness of domestic construction companies.

• Journal of Ginseng Research
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• v.41 no.3
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• pp.290-297
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• 2017

Background: The use of X-ray phase-contrast microtomography for the investigation of Chinese medicinal materials is advantageous for its nondestructive, in situ, and three-dimensional quantitative imaging properties. Methods: The X-ray phase-contrast microtomography quantitative imaging method was used to investigate the microstructure of ginseng, and the phase-retrieval method is also employed to process the experimental data. Four different ginseng samples were collected and investigated; these were classified according to their species, production area, and sample growth pattern. Results: The quantitative internal characteristic microstructures of ginseng were extracted successfully. The size and position distributions of the calcium oxalate cluster crystals (COCCs), important secondary metabolites that accumulate in ginseng, are revealed by the three-dimensional quantitative imaging method. The volume and amount of the COCCs in different species of the ginseng are obtained by a quantitative analysis of the three-dimensional microstructures, which shows obvious difference among the four species of ginseng. Conclusion: This study is the first to provide evidence of the distribution characteristics of COCCs to identify four types of ginseng, with regard to species authentication and age identification, by X-ray phase-contrast microtomography quantitative imaging. This method is also expected to reveal important relationships between COCCs and the occurrence of the effective medicinal components of ginseng.

• 제어로봇시스템학회:학술대회논문집
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• 1998.10a
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• pp.129-134
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• 1998

In this paper, a simple method is presented to synthesize a transfer function from experimentally obtained gain and phase data. The method we offer here is based on the previous method given by M.Hassul etc. [1], where they proposed relevant formulas in a straightforward manner so that undergraduate students could follow the development more easily. This method, however, inevitably is accompanied by a significant difference between the real and identified model especially in the low frequency region. We solve this problem by introducing a new weighting function that can be determined by using the additive uncertainty of the Identified transfer function.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.40 no.7
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• pp.273-281
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• 2003

This paper proposes a new time synchronization scheme for the Automatic Identification System(AIS). The proposed scheme utilizes a Temperature Compensated Crystal Oscillator(TCXO) as a local reference clock, and consists of a Digitally Controlled Oscillator(DCO), a divider, a phase comparator, and register blocks. Primary time reference is IPPS from GPS receiver that is synchronized to Universal Time Coordinated(UTC). And if GPS is unavailable, other station's signal is utilized as secondary time reference. The phase comparator measures time difference between the 1PPS and the generated transmit clock. The measured time difference is compensated by controlling the DCO and the transmit clock is synchronized to the Universal Time Coordinated(UTC). The synchronized transmit clock(9600Hz) is divided into the transmitting time slot(37.5Hz). The proposed scheme is tested in an experimental AIS transponder set. The experimental result shows that the proposed module satisfies the timing specification of the AIS technical standard, ITU-R M.1371-1.