• Proceedings of the KSME Conference
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• 2001.06e
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• pp.373-379
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• 2001

When a train runs into a tunnel at high-speed, aerodynamic drag suddenly increases and the booming noise is generated at the exit of tunnel. The noise shape is very important to reduce the aerodynamic drag in tunnel as well as on open ground, and the micro-pressure wave that is a source of booming noise is dependent on nose shape, especially on area distribution. In this study, the nose shape has been optimized employing the response surface methodology and the axi-symmetric compressible Navier-Stokes equations. The optimal designs have been executed imposing various conditions of the aerodynamic drag and the micro-pressure wave on object functions. The results show that the multi-objective design was successful to decrease micro-pressure wave and aerodynamic drag of trains.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.1394-1397
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• 2005

The object of this study was to design of micro stage, which is one of the equipments embodied in ultra precision positioning mechanism. Design factors for micro stage were decided a roundness of hinge, a thickness of hinge, a thickness of stage, a length of arms and a clearance of division. To obtain the $1^{st}$ natural frequency and equivalent stresses, FEM simulation was performed using the table of orthogonal arrays and Taguchi method was used to determine the optimal design parameters. As results of this study, the size of 1st natural frequency and equivalent stresses on micro stage was influenced significantly by a thickness of hinge and a length of arm.

• Proceedings of the IEEK Conference
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• 2008.06a
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• pp.919-920
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• 2008

In this paper, we present early processing techniques for visual inspection of metallic parts. Since metallic surfaces give rise to specular reflections, it is difficult to extract object boundaries using elementary segmentation techniques such as edge detection or binary thresholding. In this paper, we present two techniques for finding object boundaries on micro bit images. First, we explain a technique for detecting blade boundaries using a directional correlation mask. Second, a line and angle extraction technique based on Harris corner detector and Hough transform is described. These techniques have been effective for detecting blade boundaries, and a number of experimental results are presented using real images.

• Journal of International Society for Simulation Surgery
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• v.3 no.1
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• pp.16-21
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• 2016

Computed tomography (CT) can completely digitize the interior and the exterior of nearly any object without any destruction. Generally, the resolution for industrial CT is below a few microns. The industrial CT scanning, however, has a limitation because it requires long measuring and processing time. Whereas, 2D X-ray imaging is fast. In this paper, we propose a novel concept of 3D non-destructive inspection technique using the advantages of both micro-CT and dual X-ray images. After registering the master object’s CT data and the sample objects’ dual X-ray images, 3D non-destructive inspection is possible by analyzing the matching results. Calculation for the registration is accelerated by parallel computing using graphics processing unit (GPU).

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.5 no.1
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• pp.39-44
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• 2006

Ultra precision positioning mechanism has been widely used on semiconductor manufacturing equipments, optical spectrum analyzers and cell manipulations. Ultra precision positioning mechanism consists of several actuators, sensors, guides and control systems. Its efficiency depends on each performance of components. The object of this study is to design and analyze the micro stage that is one of the equipments embodied in ultra precision positioning mechanism. The micro stage consists of PZT actuators and flexure hinges. The structural design of flexure hinge is optimized by using RSM and FEM. The control factors concerned with the design of flexure hinges of stage and arms are optimized by minimizing the equivalent stress on the hinge and maximizing 1st natural frequency based on RSM and FEM simulation under various kinds of design conditions.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.16 no.5
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• pp.198-204
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• 2007

This study was carried out to develope a flow control system using to supply PR(photo-resist) in the semi-conductor manufacturing process. The features of this system are to be able to measure the high viscosity and micro-flow. To meet above study object some ideas was induced to design a new concept valve with new material, multi-cross wheel, and new sealing method etc.. As the evaluations on the developed micro-flowmeter it was enough satisfied to use at the IT industries such as photo-resist process.

• Proceedings of the IEEK Conference
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• 1999.11a
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• pp.905-908
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• 1999

In this paper, we present a polysilicon actuator on silicon wafer using surface micromachining technology which employs an electrostatic stepwise driven Scratch Drive Actuator to generate a force that can move an external object. For optical applications, we propose wavelength selector using distributed feedback structures and this micro actuator.

• Journal of the Optical Society of Korea
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• v.10 no.4
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• pp.178-183
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• 2006

An in-line phase-shifting digital holographic microscopy system was constructed by inserting a conventional microscope in the object arm of a Mach-Zehnder interferometer. It was used to measure the three dimensional shape of a micro Fresnel lens. It was also shown that both the lateral and the axial resolutions of the in-line phase-shifting system using a self-calibration algorithm were superior to those of the best off-axis system.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2005.05a
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• pp.335-341
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• 2005

The development of Shadow Moire in many kinds of methods for acquiring 3-dimensional information from an object is written in this paper. The fringe is appeared, when a grating mask makes its shadow on the object. The object is moved along x-axis more then 3 times to get phases from its fringe that contains data of the object's height. PMP{Phase Measuring Profilometry) is used for analyzing these images from a CCD camera. The calculated phase is remedied for expending the restricted results due to range of the $tan^{-1}$.

• Journal of the Korean Society for Precision Engineering
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• v.22 no.7 s.172
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• pp.164-169
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• 2005

The micro-gripper system is one of the systems that should be improved in the respect of performance for practical usage. In the previous works, the important issues are considered and presented using axiomatic design approach. In this paper, the functional requirements and design parameters are evaluated in order to improve the performance and efficiency of the system. The evaluation is a very difficult task since many variables are related to the outcomes. To provide a basis for correct design decisions, axiomatic design principles have been advanced. Since the framework of axiomatic design makes design issues easier to understand when they are analyzed, we used those as an evaluation tool. The object of the system is to handle micro-size parts. Main device is a micro-gripper using two bender-typed and one stack-typed PZTs as actuators. And it has three tips made of tungsten wires fur holding function. Also the system must satisfy other functional requirements for appropriate handling performance. The results of this study show design improvements of micro-gripper system such as structural change of gripper, additional element, and integration of physical parts. Axiomatic design guides presented suitable design parameters corresponding to functional requirements and made the design elements improve through diagrams of whole system.