• Journal of the Institute of Convergence Signal Processing
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• v.19 no.3
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• pp.125-132
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• 2018

KVN(Korean VLBI Network) introduced the Mark6 system of the MIT haystack observatory as a recorder for data recording up to 32 Gbps for VLBI(Very Long Baseline Interferometry) observation. The Mark6 recorder can record data at up to 32Gbps when two systems and 64 HDDs are installed. However, because of the unique recording method that is characteristic of Mark6, we are introducing a large amount of data into a virtual file system, or using a general RAID method, which causes data loss when reading and transferring files at the highest recording speed or file system have. The Flexbuff system, a software recorder developed by JIVE(Joint Institute for VLBI ERIC), can be configured to operate as a data recorder through RAID configuration and network upgrades. In particular, when installed in the Mark6 system, it can record VLBI data at a maximum speed of 32 Gbps with less loss of data compared to the existing Mark6 by utilizing Mark6 resources well. In this paper, we propose that the existing Mark6 system can be operated as Mark6-Flexbuff by installing jive5ab software, and it is verified through experiment that it can be effectively used for VLBI observation operation through data recording test.

• 제어로봇시스템학회:학술대회논문집
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• 1990.10a
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• pp.811-815
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• 1990

This paper describes the method on image acquisition and image processing in the turning process. The formation of discontinuous chips during high-speed oblique cutting without lubricant was observed by means of video camera recorder and stroboscope. The image processing technique for chip flow is described and the results are presented for variable feeds. It is concluded that experimental values of chip flow angle are similar to theoretical values of Stabler's rule.

• Journal of the Institute of Convergence Signal Processing
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• v.17 no.2
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• pp.83-92
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• 2016

In this paper, we introduce the results of the testing and observation systems for performance wideband expansion in the Korean VLBI Network(KVN). The KVN performs VLBI observations to 1024 Mbps data rate, and 8192 Mbps observing for four simultaneous observation is now evaluating for normal operation. The VLBI stations in several world countries developed their own wideband observing systems to observe the celestial objects with high precision and high resolution or are working with several countries. The KVN is planning to introduce a high-speed sampler, OCTAD, for sampling directly up to 2048 MHz bandwidth for RF signal of K/Q/W/D band in the frequency band without conversion. Therefore, as a preliminary study for the performance scalability of the KVN then through the close cooperation with National Astronomical Observatory of Japan (NAOJ), the OCTAD high-speed sampler and OCTADISK2 high-speed recorder were installed in the KVN Yonsei station, and verify the performance through a wideband.

• Proceedings of the KIEE Conference
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• 1996.07b
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• pp.1170-1172
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• 1996

Analog-digital converter boards for use in personal computers have recently being improved markedly, many kinds of high speed(1 MHz - 10 MHz sampling rale) and over 12-bit vertical resolution A/D boards released. It can be applicable to high frequency magnetic measurements. In measurement of magnetic properties of high frequency, digitizing oscilloscope or trasient recorder are being used. but, those price are often expensive, we constructed PC controlled A-C B-H loop tracer that can measure Bs, Br, He, permeability and may be applied about 100 Hz - 20 kHz range. it use IBM PC compatible 1 M Sample/s, 12 bit A/D converter board with SSH(Simultaneous Sample and Hold).

• Fashion & Textile Research Journal
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• v.14 no.3
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• pp.486-491
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• 2012

This study examined the sound characteristics of Taekwondo uniform fabrics to investigate the relationship between the sound parameters and the mechanical properties of the fabric as well as to provide the conditions to maximize the frictional sound of the uniform. Frictional sounds of 6 fabrics for Taekwondo uniforms were generated by the Simulator for Frictional Sound of Fabrics. The frictional speeds were controlled at low(0.62 m/s), at mid(1.21 m/s) and at high(2.25 m/s) speed, respectively. The frictional sounds were recorded using a Data Recorder and Sound Quality System subsequently, the physical sound properties such as SPL(Sound Pressure Level) and Zwicker's psychoacoustic parameters were calculated. Mechanical properties of specimens were measured by KES-FB. The SPL, Loudness(Z) values increased while Sharpness(Z) value decreased. In the physical sound parameter, specimen E had the highest SPL value at low speed and specimen B at high speed. In case of Zwicker's psychoacoustic parameters, the commercially available Taekwondo uniform fabrics(E, F) showed higher values of Loudness(Z), Sharpness(Z), and Roughness(Z), that indicates they can produce louder, shaper and rougher sounds than other fabrics for Taekwondo uniforms. The decisive factors that affected frictional sounds for Taekwondo uniforms were W(weight) as well as EM(elongation at maximum load) at low speed and WC(compressional energy) at high speed.

• Journal of Korea Foundry Society
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• v.14 no.6
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• pp.576-589
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• 1994

Water modeling experiments and computer simulation for the predictions of defects of die castings are very important to produce high quality castings with less cost. The relation between the variable air vent system and the characteristics of the fluid flow in the die cavity is studied by using water modeling tests, which give ideas on reasonable designing of die cavity, vent arrangement and gating system. In order to test the water modeling, injection is done by using water containing NaCl. Flow behaviors in cavities are visualized by high speed camera and video tape recorder, and local filling time is measured with electrode sensors. Special attention is paid to the configuration of die cavity. Simulated results by computer are examined and compared with the results of water modeling experiments. There are close correlations between the simulated results and water modeling ones.

• Proceedings of the KIEE Conference
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• 1998.11a
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• pp.82-84
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• 1998

LDM(Linear DC Motor) are used in high speed, high-precision position control system. Because of these advatages, LDM has already used in the motor of pen-recorder, magnetic-disk devices. Under the limited dimension, we propose the design method of LDM by magnetic circuit. In this paper, a relation between the thrust constant and size of a LDM that is moving coil type with unipolar is described, which is defined as a simple relational equation. To maximize the rate of thrust to the volume of LDM, the magnetic flux density in the yoke is adjusted to the value of magnetic equation By the magnetic field analysis(FEM), the validity of the equation is confirmed.

• Publications of The Korean Astronomical Society
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• v.19 no.1
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• pp.101-107
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• 2004

This paper describes the digital back-end system for getting the data to analyze the user observation mode by digitalize the analog data after receiving the space radio using the radio telescope, The received analog data will be digitalized by high-speed sampler with 1 Gsps for 4 channel frequency band of millimeter wave, and the digital data will be transported through the fiber-optic digital transmission system and WDM(wavelength division multiplex) to observation building, The wideband digital FIR(Finite Impulse Response) filters analyze the data for user observation mode to record the data in high-speed recorder with 1 Gbps. In this paper, we introduce the overall system configuration and features combined by various information and communication technology in radio astronomy briefly, which will be adopted by KVN(Korean VLBI Network).

• The Journal of the Korea Contents Association
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• v.12 no.12
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• pp.135-145
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• 2012

This study is a research development case study on the free-standing Network based camera video recording DVR. The DVR devices till now have recorded data by converting and compressing analogue video to digital, but in the future, digital videos will be recorded directly through the network camera. Also, digital compressing methods are progressing from MPEG-4, MJPEG, to H.264 method, with products considering high definition compression efficiency, minimized data size, network compatibility, and fast pending time. According to this, in 2012, it is predicted that network camera and video devices throughout the world will outrun the current analogue devices. With this transition of technological environment and fast product pending speed, a new, quality focused design is required for product development including technical realization, reliability, high-definition, compression technology, will be essential. Manufacturers are researching a new direction for the product appearance. This study considers the actual end-users as the design target and through consumer survey on preferences, design needs and required elements necessary in the design development process are extracted. Furthermore, usability and preferred images were explored through literature study and market research. Through this research process, appropriate forms for the network based DVR were analyzed, and applied into the design development process. This product will take into consideration its competitiveness and the significance of USP(Unique Selling Proposition) which is the design supremacy and professional technical skills.

• Journal of the Korean Society for Precision Engineering
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• v.15 no.2
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• pp.61-67
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• 1998

Dynamic stability in rotation of the head drum of digital VCR is very important due to the nature of high rotation speed and small angular inertia. Therefore special considerations on reducing the unbalance and assuring the stability are required the design and manufacturing process. In this paper, newly developed digital head drum is introduced. And advanced methods in analyzing and reducing the unbalance is suggested. LDV(Laser Doppler Vibrometer) was used as a measurement system verifying our modeling and new method for balancing. Experiments show that the theoretical data estimated by modeling of shaft bending caused by unbalance mass and the measured data are almost identical. The deflection was reduced to 30％ by applying the suggested balancing method.