• ETRI Journal
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• v.35 no.2
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• pp.207-217
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• 2013

This paper introduces the modular cellular neural network (CNN), which is a new CNN structure constructed from nine one-layer modules with intercellular interactions between different modules. The new network is suitable for implementing many image processing operations. Inputting an image into the modules results in nine outputs. The topographic characteristic of the cell interactions allows the outputs to introduce new properties for image processing tasks. The stability of the system is proven and the performance is evaluated in several image processing applications. Experiment results on texture segmentation show the power of the proposed structure. The performance of the structure in a real edge detection application using the Berkeley dataset BSDS300 is also evaluated.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.40 no.12
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• pp.1203-1210
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• 1991

This paper proposes a new distance relaying method based on fault initiated travelling waves for transmission line protection. The characteristics of this method are ultra high speed and excellent sensitivity. Travelling wave technique which is one of the distance relaying methods uses the discrete cross correlation function for discrimination between internal and external fault is remarkably reduced in case of a close up fault and an inception angle near or equal to zero fault. To cope with this problem, a new fast algorithm which uses backward wave summation method with fixed window is presented. The proposed method has been tested by numerical simulations using the EMTP.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.34 no.3
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• pp.873-883
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• 2014

This study proposed an estimation method of allowable wave height for loading and unloading of the ship considering ship motion that is affected by ship sizes, mooring conditions, wave periods and directions. The method was examined validity by comparison with wave field data at pier $8^{th}$ in Pohang new harbor. The wave field data obtained with wave height of 0.10~0.75m and wave period of 7~13s in ship sizes of 800~35,000ton when a downtimes have occurred. On the other hand, the results of allowable wave height for loading and unloading of the ship in this method have obtained with wave heights of 0.19~0.50m and wave periods of 8~12s for ship sizes of 5,000, 10,000 and 30,000ton. Thus this method well reproduced the field data respond to various a ship sizes and wave periods. And the results of this method tended to decrease in 16~62% when have considered long wave, and it is decreased in 0~46% when didn't consider long wave than design standards in case of the ship sizes of 5,000~30,000ton, wave period of 12s and wave angle of $75^{\circ}C$. The allowable wave heights for loading and unloading of the ship proposed by design standards are didn't respond to various the ship sizes and wave periods, and we have found that the design standards has overestimated on smaller than 10,000ton.

• Journal of Ocean Engineering and Technology
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• v.25 no.6
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• pp.23-28
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• 2011

In this paper, a new generation method for ship induced waves is proposed using the fully non-linear 3-D numerical model with non-reflected wave generation system (LES-WASS-3D). A ship induced wave generated by the newly proposed method is examined in comparison with that obtained by an empirical formula. It is then shown that there is a good agreement in free surface the elevation between them. As a result, it is revealed that a ship induced wave in a 3-D numerical wave field can be simulated well using LES-WASS-3D.

• Tribology and Lubricants
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• v.14 no.4
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• pp.100-107
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• 1998

A new bearing concept, the wave journal bearing, has been developed to improve the static and dynamic performance of a hydrodynamic journal bearing. This concept features a wave in bearing surface. Not only straight but also twisted wave journal bearing are investigated numerically. The performances of straight and twisted bearings are compared to a plain journal bearing over a wide range of eccentricity. The bearing load and stability characteristics are dependent on the geometric parameters such as the number of waves, the amplitude and the start point of the wave relative to the applied load direction. The wave journal bearing, especially for the twisted one, offers better stability than the plain journal bearing under all eccentricity and load orientation.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 1998.04a
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• pp.190-197
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• 1998

A new bearing concept, the wave journal bearing, has been developed to improve the steady and dynamic performance of a hydrodynamic journal bearing. This concept features a wave in inner bearing surface. Not only straight but also twisted wave journal bearing are investigated numerically. The performances of straight and twisted bearings are compared to a plain journal bearing over a relatively wide range of eccentricity. The bearing load and stability characteristics are dependent on the geometric parameters such as the number of waves, the amplitude and the starting point of the wave relative to the applied load. The wave journal bearing, especially for the twisted one, offers better stability than the plain journal bearing under all eccentricity and all wave to load orientation.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2001.04a
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• pp.61-65
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• 2001

A new flaw detection technique using by SH angle beam method has been discussed. The SH-wave is horizontally polarized shear wave and the surface SH wave has a characteristic of traveling along near surface layer. The surface SH wave technique is valuable for the detection of fatigue cracks at fillet weld heels which cannot be detected by other ultrasonic technique such as angle beam technique and The dispersion curves of it has simple characterization. In this work, using these beneficial chraterization, quality evaluation of spot weld with ultrasonic sound intensity of SH-wave passing through nugget area of spot weld are verified experimentally.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2008.04a
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• pp.852-855
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• 2008

In this paper, we proposed a new type's PZT actuator using surface acoustic wave. This actuator uses Rayleigh wave as an operational traveling wave. For the development of the actuator, each components of surface acoustic wave motor like PZT substrate, slider and IDT was studied theoretically and fabricated. For the measurement of transfer function of PZT substrate and operation of surface acoustic wave motor, network analyzer and 13.56MHz RF generator were used. Also the model which expresses the driving characteristic best was suggested and simulation was executed for the suggested model. And the future research works for improvement of SAW actuator was suggested.

• Proceedings of the Korea Concrete Institute Conference
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• 1997.04a
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• pp.537-543
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• 1997

A new procedure for the advanced one-side measurement of longitudinal wave and surface wave velocities in concrete is presented in this paper. Stress waves are generated in a consistent fashion with a DC solenoid. Two piezoelectric accelerometers are mounted on the surface of a specimen as receivers. Stress waves propagate along the surface of the specimen and are detected by the receivers. In order to reduce the large incoherent noise levels of the signals, signals are collected and manipulated by a computer program for each velocity measurement. For a known distance between the two receivers and using the measured flight times, the velocities of the longitudinal wave and the surface wave are measured. The velocities of the longitudinal wave determined by this method are compared with those measured by conventional methods on concrete, PMMA and steel.

• Steel and Composite Structures
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• v.32 no.2
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• pp.213-223
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• 2019

For the first time, longitudinal and transverse wave propagation of triclinic nanobeam is investigated via a size-dependent shear deformation theory including stretching effect. Furthermore, the influence of initial stress is studied. To consider the size-dependent effects, the nonlocal strain gradient theory is used in which two small scale parameters predict the behavior of wave propagation more accurately. The Hamiltonian principle is adopted to obtain the governing equations of wave motion, then an analytic technique is applied to solve the problem. It is demonstrated that the wave characteristics of the nanobeam rely on the wave number, nonlocal parameter, strain gradient parameter, initial stress, and elastic foundation. From this paper, it is concluded that the results of wave dispersion in isotropic and anisotropic nanobeams are almost the same in the presented case study. So, in this case, triclinic nanobeam can be approximated with isotropic model.