• Journal of the Korean Magnetics Society
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• v.14 no.4
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• pp.115-119
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• 2004

We measured in-plane 2 dimensional magnetization vector using two pick-up coil sets and investigate the relationship between magnetization vector and anisotropic magnetoresistance. We can determine magnetization vector by measuring magnetic moment in x and y direction simultaneously. As the uniaxial magnetic anisotropy of permalloy film increases, magnetoresistance approaches the expectation which is calculated from the angle between current vector and magnetization vector. Magnetoresistance ratio is linearly proportional to the y moment magnitude which is parallel to the current direction.

• Journal of the Korean Magnetics Society
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• v.7 no.2
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• pp.109-116
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• 1997

This paper describes an implementation of the rotational hysteresis analysis using the finite element method and a vector hysteresis model. The vector hysteresis model is extended from the magnetization-dependent Preisach model. The magnetization of each element is calculated for a given history of the rotating field. The lagging angle and the magnitude of the magnetization for an applied field are evaluated. The experimental results show that the magnetization characteristics of the magnetic materials under the rotating field can be analyzed accurately by the proposed method.

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 1996.06a
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• pp.390-393
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• 1996

• Geophysics and Geophysical Exploration
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• v.27 no.2
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• pp.119-128
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• 2024

Marine magnetic surveys provide a rapid and cost-effective method for pioneer geophysical survey for many purposes. Sea-surface magnetometers offer high accuracy but are limited to measuring the scalar total magnetic field and require dedicated cruise missions. Shipboard three-component magnetometers, on the other hand, can collect vector three components and applicable to any cruise missions. However, correcting for the ship's magnetic field, particularly viscous magnetization, still remains a challenge. This study proposes a new additional correction method for ship's viscous magnetization effect in vector data acquired by shipboard three-component magnetometer. This method utilizes magnetic data collected simultaneously with a sea-surface magnetometer providing total magnetic field measurements. Our method significantly reduces deviations between the two datasets, resulting in corrected vector anomalies with errors as low as 7-25 nT. These tiny errors are possibly caused by the vector magnetic anomaly and its related viscous magnetization. This method is expected to significantly improve the accuracy of shipborne magnetic surveys by providing corrected vector components. This will enhance magnetic interpretations and might be useful for understanding plate tectonics, geological structures, hydrothermal deposits, and more.

• The Journal of the Acoustical Society of Korea
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• v.10 no.4
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• pp.27-37
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• 1991

This paper proposes the ESFVQ(energy subspace fuzzy vector quantization) that employs energy subspaces to reduce the quantizing distortion which is less than that of a fuzzy vector quatization. The ESFVQ is applied to a speaker adaptation method by which Korean words spoken by unknown speakers are recognized. By generating mapped codebooks with fuzzy histogram according to each energy subspace in the training procedure and by decoding a spoken word through the ESFVQ in the recognition proecedure, we attempt to improve the recognition rate. The performance of the ESFVQ is evaluated by measuring the quantizing distortion and the speaker adaptive recognition rate for DDD telephone area names uttered by 2 males and 1 female. The quatizing distortion of the ESFVQ is reduced by 22% than that of a vector quantization and by 5% than that of a fuzzy vector quantization, and the speaker adaptive recognition rate of the ESFVQ is increased by 26% than that without a speaker adaptation and by 11% than that of a vector quantization.

• Geophysics and Geophysical Exploration
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• v.12 no.1
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• pp.17-26
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• 2009

On Aogashima Island, a volcanic island located in the southernmost part of the Izu Seven Islands Chain, vector magnetic anomalies were obtained in a helicopter-borne magnetic survey. The purpose of this study was to understand the volcanic structure of Aogashima Island in order to mitigate future disasters. Commonly, to obtain the magnetic structure of a volcanic island, total intensity anomalies (TIA) have been used, even though they have intrinsic errors that have not been evaluated correctly. Because the total intensity magnetic anomaly (TIA) is not a physical value, it does not satisfy Maxwell's Equations, Laplace's Equation, etc., and so TIA is not suitable for any physical analyses. In addition, it has been conventionally assumed that TIA is the same as the projected total intensity anomaly vector (PTA) for analyses of TIA. However, the effect of the intrinsic error ($\varepsilon_T$ = TIA.PTA) on the analysis results has not been taken into account. To avoid such an effect, vector magnetic anomalies were measured so that a reliable analysis of Aogashima Island magnetization could be carried out. In this study, we evaluated the error in TIA and used vector anomalies to avoid this erroneous effect, in the process obtaining reliable analysis results for 3D, vector magnetization distributions. An area of less than 1 A/m magnetization was found in the south-west part of Aogashima Island at the depth of 1.2 km. Taking the location of fumarolic activity into consideration, the lower-magnetization area was expected to be the source of that fumarolic activity of Aogashima Island.

• Journal of the Korean Institute of Intelligent Systems
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• v.7 no.4
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• pp.18-28
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• 1997

This paper presents image data compression using a classified vector quantization (CVQ) which categories edge blocks according to the energy distribution of subimages in the discrete cosine transform domain. Classifying the edge blocks enhances visual quality of the compressed images while maintaining a high compression ratio. The proposed classification method categories subimages into eight lypes of edge features according to an energy distribution. A neural network, trained with the data generated from the proposed classification method, can successfully classify subimages to eight edge categories. Experimental results are given to show how the (1VQ method incorporatd with a neural network can produce faithful compressed image quality for high compression ratios.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.13 no.2
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• pp.39-45
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• 1999

In case of field weakening region, torque is directly affected by flux. In this region, the flux reference is cIecreased inversely proportional to the rotor speed. As the flux is decreased, the magnetizing inductance is nonnally increased The increased magnetizing inductance limited voltage for controlling current In this paper, rreasuring q axis voltage in field weakening region, magnetizing inductance in flux calculating can be readjusted. Computer simulation and experiment results demostrate the efficacy of the prqx>sed rrethod. Proposed algorithm is expected to the application of the adjustable drive system in the spinning and weaving field. field.

• Journal of KSNVE
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• v.10 no.2
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• pp.331-337
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• 2000

The necessity of diagnosis of the rotating machinery which is widely used in the industry is increasing. Many research has been conducted to manipulate field vibration signal data for diagnosing the fault of designated machinery. As the pattern recognition tool of that signal, neural network which use usually back-propagation algorithm was used in the diagnosis of rotating machinery. In this paper, self-organizing feature map(SOFM) which is unsupervised learning algorithm is used in the abnormal defect diagnosis of rotating machinery and then learning vector quantization(LVQ) which is supervised learning algorithm is used to improve the quality of the classifier decision regions.

• Journal of the Korean Magnetics Society
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• v.26 no.5
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• pp.149-153
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• 2016

In Fe/Gd multilayers, patterning effect on the interlayer coupling was studied by comparing patterned and unpatterned samples that were cut from a multilayer film. A comparative study of the two samples via temperature dependent Gd-specific magnetization vector using X-ray magnetic circular dichroism (XMCD) shows that the temperature dependence of the Gd magnetization vector can be modified in the patterned sample due to a competition between the patterning and antiferromagnetic interlayer coupling effects.