• Smart Structures and Systems
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• v.6 no.4
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• pp.389-403
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• 2010

By using image recognition technology, this paper presents a new fault diagnosis method for rotating machinery with artificial immune algorithm. This method focuses on the vibration state parameter image. The main contribution of this paper is as follows: firstly, 3-D spectrum is created with raw vibrating signals. Secondly, feature information in the state parameter image of rotating machinery is extracted by using Wavelet Packet transformation. Finally, artificial immune algorithm is adopted to diagnose rotating machinery fault. On the modeling of 600MW turbine experimental bench, rotor's normal rate, fault of unbalance, misalignment and bearing pedestal looseness are being examined. It's demonstrated from the diagnosis example of rotating machinery that the proposed method can improve the accuracy rate and diagnosis system robust quality effectively.

• Proceedings of the Korean Geotechical Society Conference
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• 2006.03a
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• pp.402-413
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• 2006

Strength evaluation of soft soils is a formidable task because of difficulties in sampling, specimen preparation and setting in triaxial cells. In undrained triaxial testing, sampling disturbance, verticality of specimen and bedding effect give a great influence on shear strength measurements. In the other hand, shear wave measurements of specimens are less influenced by these factors. In this research, the bender elements were attached top cap and base pedestal of triaxial cell and shear wave velocities were measured. To initiate a methodology to evaluate shear strength indirectly by measuring shear wave velocity, a relationship between shear strength and shear wave velocity was developed with kaolinite specimens consolidated in the laboratory. Undrained shear strength turns out to increase linearly with shear wave velocity. Stress-strain curves can also be predicted with a hyperbolic model and shear wave measurements.

• Proceedings of the Korea Concrete Institute Conference
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• 1993.10a
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• pp.207-212
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• 1993

When constructing highly precise production plants, for example, super LSI plants or semiconductor plants, it is important to take the necessary control countermeasures into consideration to obtain the working microvibration environment, which is directly related to product precision. Working environment of a clean room means vibration-free and there are only ultra-miro vibration which human cannot sense. In order to provide an place having a vibration-free working environment with only ultra-micro vibration it is necessary to posses a great number of vibration isolation technlogies, wide-ranging and abundant survey and teat data, and a high level of knowledge enabling comprehensive judgments to be made. In this study, experimental modal analysis is used to analyze the dynamic characteristics of double floor for vibration-proofing near apparatus which generate vibration. It is concluded that the double floor system with rubber pad inserted between floor panel and pedestal is good for vibration proof.

• Proceedings of the Korean Society of Marine Engineers Conference
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• 2006.06a
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• pp.107-108
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• 2006

This paper presents the design of a night vision system for vessels. Both a hardware system and software modules for stabilization control are developed. In order to stabilize each control axis, the two-degree of freedom(TDF) PID controller is designed and its parameters are tuned using a real-coded genetic algorithm(RCGA). Simulation demonstrates the effectiveness of the proposed system.

• Proceedings of the KSR Conference
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• 2001.10a
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• pp.235-239
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• 2001

The bogie of high speed freight car running on conventional line is welded bogie modeled on Y25 bogie developed in Europe. Y25 bogie has speed limit of 110km/h. But it has limiting factors to speed-up as increasing maintenance cost and friction parts pedestal. And also it was reported that cracks are found in the parts where center beam meet bolster and endbeam near bracket for braking part. This study includes stress analysis improved structure of welded bogie for strength evaluation by numerical method and experimental method. According to the study, new configuration bogie shows improvement in strength.

• Journal of the Korea Furniture Society
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• v.25 no.1
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• pp.55-60
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• 2014

The objective of this study was to date a Buddhist wooden Tablet (No. 271) at Songkwangsa Temple, Suncheon, Korea, using wiggle matching of radiocarbon dates. For wiggle matching, three samples (2nd, 16th and 34~35th rings from inner side) in the pedestal of the Tablet were selected among total of 37 tree rings. Wiggle matching the radiocarbon dates of three samples resulted in A.D. 1660~1679 (95.4% confidence interval) for the outermost ring. This interval suggested the age of this tablet as the late 17th century, which was almost at the same age as other early Buddhist tablets in Korea.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2004.05a
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• pp.657-662
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• 2004

This paper presented is a case study of a real compressor rotor of a refinery plant for high speed balancing of flexible rotor. The rotor was tested in the expert high-speed balancing facility established by KIMM at early 2004. The capability of the facility can reach 40000rpm in rotation speed and 8 ton in rotor weight for high-speed balancing. The facility performs multi-plane at-speed balancing using influence coefficient from the vibration data measured at two pedestals. The test rotor had exceeded permissible criteria of vibration at initial run. But by processing a low-speed balancing at 1000 rpm and six trial run trying to calculate influence coefficient of rotor to the range of operating speed, the final result of high-speed balancing revealed a remarkable reduce of vibration at pedestal of the rotor.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2000.06a
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• pp.1871-1874
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• 2000

It is impossible to predict accurately the dynamic behavior of turbine-generator system because bearing, and rotor characteristics are nonlinear and different from temperature, load, operation speed and bearing lubricant oil property. Especially, the characteristics of turbine hoods affect much the entire vibration characteristics of turbine. As the dynamic stiffness of turbine hoods are changed, the critical speeds of rotor are shifted. In this paper, the vibration behavior of turbine-generator is analyzed by using component mode synthesis and the critical speeds measured during shut-down are compared with the analytic results. It is confirmed that the 1st natural frequency and the mode shape are well in agreement with actual measured data.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.1360-1361
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• 2008

This paper presents the surface potential rise distribution near grounding electrodes produced by ground fault currents. The small-scale model with the foundation pedestal in hemispherical tank was used to simulate the ground fault condition of the electrical installations for street lamps. When entering the fault current through the test ground electrode, surface potential rise, potential gradient, touch and step voltages for different grounding electrode shapes were measured, and the results obtained were discussed.

• Journal of the Korean Society of Industry Convergence
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• v.12 no.1
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• pp.19-25
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• 2009

We suggest and evaluate a dynamic scheduling rule of machines and material handling systems for on-line operation in job shop type Flexible Manufacturing System. Alternating status should be able to take operation scheduling procedures and without delay in dynamic industrial environments effectively. The interaction(SPT-NS, SPT-QSNS, SPT-NUJ, EDD-NS, EDD-QSNS, EDD-NUJ, CR-NS, CR-QSNS, CR-NUJ) between machine operation scheduling and AGV dispatching rule were also studied in this research. The performance evaluation which was obtained from DSS compares the performance of Flow time, and Empty to loaded travel ratio. It is Compared with the best rules & two system.