• Journal of computational fluids engineering
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• v.11 no.2 s.33
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• pp.56-61
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• 2006

As the size and dimension of target problems in the field of computational engineering including CFD gets bigger and higher, it is needed to have more efficient and flexible data visualization environment in terms of software and hardware. Even though it is still manageable to use a mouse in controlling 3-dimensional data visualization, it would be beneficial to use 3-D input device for 3-D visualization. 'Data Glove' is one of the best 3-D input devices, because human hands are best tools for understanding 3-D space and manipulating 3-D objects. Signals coming from 'Data Glove' are analog and very sensitive to finger motions, therefore signal filtering using a digital filter is applied. This paper describes our experience and benefits of using data gloves in controlling 3-dimensional postprocessing softwares.

• Journal of the Korean Society of Visualization
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• v.9 no.2
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• pp.21-26
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• 2011

Hydrodynamic focusing technique to generate focused flow has been used for flow cytometry in microfluidic devices. However, devices with circular capillary tubes made of glass are not suitable for flow visualization or optical signal detection because the rays of light are distorted at the curved interface. We devised a new acrylic chamber assembled with a pulled micropipette and a rectangular microchannel made of glass. This new channel geometry enabled us to visualize the three-dimensional (3D) flow characteristics with confocal imaging technique. We analyzed the 3D hydrodynamic focusing in a circular capillary tube and a rectangular microchannel over a practical range of flow rates, viscosities and pressure drops.

• Journal of Institute of Control, Robotics and Systems
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• v.20 no.2
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• pp.120-125
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• 2014

Conventional handheld metal detectors use a single induction coil to detect the metallic parts of explosive objects, and the detector generates an acoustic signal from its magnetic response to a metallic object so that an operator can confirm the existence of mines. Though metal detectors have very useful detection mechanisms to find mines, it is easy to cause a high false alarm ratio due to the detection of non-explosive metallic items such as cans, nails and other pieces of metal, etc. Also, because of the physical characteristic of a metal detector it is hard to detect non-metallic objects such as mines made of wood or plastic. Furthermore, the operator must move it to the left and right slowly and repeatedly to attain enough sensor signals to confirm the existence of mines using only a monotonous acoustic signal. To resolve the disadvantages of handheld detectors, many new approaches have been attempted, such as an arrayed detector and a visualization algorithm based on metal/non-metal sensor. In this paper, we introduce a visualization algorithm with a metal/non-metal complex sensor, an arrayed metal/non-metal sensor and the their testing and evaluation.

• Transactions of the Korean Society of Automotive Engineers
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• v.9 no.1
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• pp.102-111
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• 2001

To describe the air flow characteristics within an air cleaner cover and mass air flow sensor (MAFS) entry region installed in a 3.0L engine air induction system, flow visualization, velocity and turbulence intensity measurements were taken in several view planes. A detailed knowledge of the interaction between the design parameters and the flow structures will enhance our understanding of the motions within the flow field and enable engineers to optimize the induction system and reduce the signal-to-noise ratio in the MAFS output. Emphasis is placed on the analysis of coherent motions and the controlling parameters which affect the air flow in the MAFS entrance region over a flow rate of 13-240 kg/hr. The high speed motion pictures illustrated that the air flow generated within the air cleaner cover under steady state condition is quite complex. In both axial and radial planes of the main passage it was found that the flow pattern is remarkably influenced by the air cleaner cover and main passage configuration. A comparison of the flow patterns and measurements in the original and modified air cleaner cover is presented. Measurements from the MAFS indicated an significant reduction in pressure drop and signal noise for the modified cover as compared with the original cover, over an air flow rate of 13-240 kg/hr.

• Journal of ILASS-Korea
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• v.5 no.1
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• pp.49-57
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• 2000

This study presents the flow visualization results, velocity and turbulence intensity measurements made within an air filter cover and entry region of a mass air flow sensor (MAFS) which is used in an induction system of 3.8L engine. Flow structure in two air filter cover assemblies were examined. The first was a clear plastic replica of the production cover while the second was a modified clear plastic cover with a geometry configured to reduce fluctuations. High speed flow visualization and laser doppler velocimetry (LDV) systems were used to reveal and analyze the flow field characteristics encountered in the sensor design process under steady flow conditions. A 40-watt copper vapor laser was used as a light source. Its beam is focused down to a sheet of light approximately 1.5mm thick. The light scattered off the particles was recorded by a 16mm high speed rotating prism camera at 5000 frames per second. A comparison of the flow patterns and LDV measurements in the original and modified air filter covers is presented to illustrate the controlling effect of the cover design on the turbulence structure formation near the bypass and on the sensor output signal. In both axial and radial planes of the main passage it was found that the turbulence flow pattern is remarkably influenced by the air filter cover and main passage configuration.

• The Journal of Korean Association of Computer Education
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• v.10 no.1
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• pp.97-105
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• 2007

In this paper, visualization of convolution operation is presented, which is implemented by scalable vector graphics (SVG). Convolution operation is one of the basic essential concepts in the area of signal and image processing. However, it is difficult for students to intuitively understand the operation of convolution since it is mainly based on mathematical representation. We present the visualization of convolution operation and its applications which are implemented by SVG. The effects of the proposed approach have been analyzed by interviews. It has been seen that the proposed visualization of convolution operation could be effectively applied to learn the convolution operation and its applications.

• Smart Structures and Systems
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• v.26 no.5
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• pp.657-666
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• 2020

A rotational pulse-echo ultrasonic propagation imager that can inspect cylindrical specimens for material nondestructive evaluations is proposed herein. In this system, a laser-generated ultrasonic bulk wave is used for inspection, which enables a clear visualization of subsurface defects with a precise reproduction of the damage shape and size. The ultrasonic waves are generated by a Q-switched laser that impinges on the outer surface of the specimen walls. The generated waves travel through the walls and their echo is detected by a Laser Doppler Vibrometer (LDV) at the same point. To obtain the optimal Signal-to-Noise Ratio (SNR) of the measured signal, the LDV requires the sensed surface to be at a right angle to the laser beam and at a predefined constant standoff distance from the laser head. For flat specimens, these constraints can be easily satisfied by performing a raster scan using a dual-axis linear stage. However, this arrangement cannot be used for cylindrical specimens owing to their curved nature. To inspect the cylindrical specimens, a circular scan technology is newly proposed for pulse-echo laser ultrasound. A rotational stage is coupled with a single-axis linear stage to inspect the desired area of the specimen. This system arrangement ensures that the standoff distance and beam incidence angle are maintained while the cylindrical specimen is being inspected. This enables the inspection of a curved specimen while maintaining the optimal SNR. The measurement result is displayed in parallel with the on-going inspection. The inspection data used in scanning are mapped from rotational coordinates to linear coordinates for visualization and post-processing of results. A graphical user interface software is implemented in C++ using a QT framework and controls all the individual blocks of the system and implements the necessary image processing, scan calculations, data acquisition, signal processing and result visualization.

• Journal of Digital Convergence
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• v.14 no.7
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• pp.331-337
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• 2016

The purpose of this study is to provide a method to visualize the sound data to the three-dimensional image. The visualization of the sound data is performed according to the algorithm set after production of the text-based script that form the channel range of the sound data. The algorithm consists of a total of five levels, including setting sound channel range, setting picture frame for sound visualization, setting 3D image unit's property, extracting channel range of sound data and sound visualization, 3D visualization is performed with at least an operation signal input by the input device such as a mouse. With the sound files with the amount an animator can not finish in the normal way, 3D visualization method proposed in this study was highlighted that the low-cost, highly efficient way to produce creative artistic image by comparing the working time the animator with a study presented method and time for work. Future research will be the real-time visualization method of the sound data in a way that is going through a rendering process in the game engine.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.05a
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• pp.463-468
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• 2007

The abnormal sound of generator frame is analyzed by a acceleration signal. The spike-like time signal is major characteristics of impacting force. The distributional map of vibration level is one of visualization method. With map, noise source was easily detected. After de_assembly of generator, loose part of internal component is the source of impact force by mechanical movement of stator inherently. In contact condition of part with clearance, the level of impact signal is different at each revolution and impact signal did not happens periodically.

• 한국HCI학회:학술대회논문집
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• 2009.02a
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• pp.1075-1080
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• 2009

이 글은 Music Information Retrieval(MIR) 기법을 사용하여 오디오 콘텐츠의 리듬 정보를 자동으로 분석하고 이를 시각화하는 방법에 대해 다룬다. 특히 MIR을 활용한 간단한 시각화(sound visualization) 어플리케이션을 소개함으로써 음악 정보 분석이 디자인, 시각 예술에서 다양하게 활용될 수 있음을 보이고자 한다. 음악적 정보를 시각 예술로 담아내려는 시도는 20세기 초 아방가르드 화가들에 의해 본격적으로 시작되었다. 80년대 이후에는 컴퓨터 기술의 급속한 발전으로 사운드와 이미지를 디지털 영역에서 쉽게 하나로 다룰 수 있게 되었고, 이에 따라 다양한 오디오 비주얼 예술작품들이 등장하였다. MIR은 오디오 콘텐츠로부터 음악적 정보를 분석하는 DSP(Digital Signal Processing) 기술로 최근 디지털 콘텐츠 시장의 확장과 더불어 연구가 활발히 진행되고 있다. 특히 웹이나 모바일에서는 이미 다양한 상용 어플리케이션이 적용되고 있는데 query-by-humming과 같은 음악 인식 어플리케이션이 대표적인 경우이다. 이 글에서는 onset 검출(onset detection)을 중심으로 음악적 리듬을 분석하는 알고리즘을 살펴보고 기본적인 조형원리에 따라 이를 시각화하는 어플리케이션의 예를 소개한다.