• International Journal of Aeronautical and Space Sciences
• /
• v.13 no.4
• /
• pp.499-506
• /
• 2012

In this paper, a dynamic modeling for the velocity and position information of a single frequency stand-alone GPS(Global Positioning System) receiver is described. In static condition, the position error dynamic model is identified as a first/second order transfer function, and the velocity error model is identified as a band-limited Gaussian white noise via non-parametric method of a PSD(Power Spectrum Density) estimation in continuous time domain. A Kalman filter is proposed considering both correlated/white measurements noise based on identified GPS error model. The performance of the proposed Kalman filtering method is verified via numerical simulation.

• Journal of Korean Association for Spatial Structures
• /
• v.6 no.3 s.21
• /
• pp.43-50
• /
• 2006

This paper is concerned with the natural periods of ambient vibration and eigenvalue analysis. Ambient vibration tests were conducted to four bearing-wall reinforced concrete buildings ranging from twelve to nineteen stories. The performance of modeling in eigenvalue analysis was investigated using consideration of rigidity out of the plane in the slab and the non-structural bearing wall. Measured natural period was also compared with the value by the KBC2005. Natural period of the short direction in eigenvalue analysis is well fitted with the measured one. In the other hand, Natural period of the long direction in eigenvalue analysis is slightly more overestimated than the measured one. Natural period of the long direction in eigenvalue analysis was found to be enhanced by considering the effect of the stiffness out of the plane of the slab and non-structural wall in the structural modeling.

• Journal of Power System Engineering
• /
• v.3 no.2
• /
• pp.26-33
• /
• 1999

Pressure pulsation Inside the discharge and suction cavity of rotary and scroll compressor are often a major source of objectionable noise and vibration. The key factor of these noise and vibration is due to the cavity resonance. It is not only necessary to understanding the characteristics of pulsation in order to reduce the excitation force of gas to the cavity but also to verifying the phenomena of cavity resonance. For the purpose of these understandings, measurement and simulation of cavity resonance can lead to a better understandings how they occur and be very important to identify the ways to reduce the noise efficiently. In this paper, modeling of the cavity(internal acoustics inside the shell) is discussed and simulated using FEM. Results from the simulation are compared with those measurement in experiments. In describing of cavity mode by experiments, it is very important to specify the exact conditions under which they are measured. Finally, this paper shows the one example of reduced cavity resonance in the compressor.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2010.10a
• /
• pp.451-452
• /
• 2010

• Journal of the Korean Society of Fisheries and Ocean Technology
• /
• v.34 no.4
• /
• pp.393-402
• /
• 1998

• Current Optics and Photonics
• /
• v.2 no.1
• /
• pp.69-78
• /
• 2018

This paper presents a precise edge detection algorithm for the critical dimension (CD) measurement of a Thin-Film Transistor Liquid-Crystal Display (TFT-LCD) pattern. The sigmoid surface function is proposed to model the blurred step edge. This model can simultaneously find the position and geometry of the edge precisely. The nonlinear least squares fitting method (Levenberg-Marquardt method) is used to model the image intensity distribution into the proposed sigmoid blurred edge model. The suggested algorithm is verified by comparing the CD measurement repeatability from high-magnified blurry and noisy TFT-LCD images with those from the previous Laplacian of Gaussian (LoG) based sub-pixel edge detection algorithm and error function fitting method. The proposed fitting-based edge detection algorithm produces more precise results than the previous method. The suggested algorithm can be applied to in-line precision CD measurement for high-resolution display devices.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.25 no.12
• /
• pp.1228-1235
• /
• 2014

Input impedance of UHF RFID tag chip is needed to design a tag. In determining the chip impedance, direct measurement method is adopted commonly. In this paper, problems generated from fixtures that interface between tag chip and coaxial-oriented measurement instrument are investigated and the result of the problems is shown, when the direct measurement method is applied. As an alternative to the method, a modeling method is proposed and its validity and accuracy are shown.

• Journal of Industrial Technology
• /
• v.31 no.B
• /
• pp.81-90
• /
• 2011

Centrifuge modeling and numerical analysis on works of breakwater construction were performed to investigate the behavior of caisson type of breakwater and foundation treated with the method of DCM (Deep Cement Mixing) under the condition of wave action in field. In centrifuge modeling, construction sequence of breakwater caisson such as preparation of ground, treatment of DCM, installation of rubble mound, placement of breakwater caisson and lateral loading on the breakwater due to wave action were reconstructed. Lateral movement of model breakwater and ground reaction in the vertical direction were monitored during test. Stress concentration ratio between the untreated ground and the treated ground with DCM was evaluated from measurement of vertical stresses on each ground. Numerical analysis with the software of PLAXIS was carried to compare with Results of centrifuge model test. It was found that stability of model breakwater was maintained during stage of construction and the compared results about stress concentration ratio were in relatively good agreements.

• 한국전산유체공학회:학술대회논문집
• /
• 2005.04a
• /
• pp.91-95
• /
• 2005

A heat dissipation modeling method of EEE parts is developed for thermal design and analysis of an satellite electronic equipment. The power consumption measurement value of each functional breadboard is used for the heat dissipation modeling method. For the purpose of conduction heat transfer modeling of EEE parts, surface heat model using very thin ignorable thermal plates is developed instead of conventional lumped capacity nodes. The thermal plates are projected to the printed circuit board and can be modeled and modified easily by numerically preprocessing programs according to design changes. These modeling methods are applied to the thermal design and analysis of CTU and verified by thermal cycling and vacuum tests.

• Journal of the Korean Society of Manufacturing Technology Engineers
• /
• v.22 no.3
• /
• pp.394-401
• /
• 2013

A new Rockwell hardness (HRC) model using a volumetric parameter by a least square and fractal interpolation method is suggested. The results are also investigated in comparison to real measured hardness data. For this purpose, the measurement of an indented volume is performed using a confocal laser scanning microscope (CLSM), and the captured height encoded image (HEI) is used as an original surface for the calculation of the indented volume. After configuring the surface, the constructed volume is calculated and used as an independent variable for HRC hardness modeling. The hardness model is established using an experimental modeling technique involving a least square algorithm and fractal interpolating model, and this suggested model can be used to reliably predict the Rockwell hardness. These techniques can also be applied to the modeling of the Brinnell and Vickers hardnesses using a volumetric variable.