• Proceedings of the KSR Conference
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• 2000.11a
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• pp.733-739
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• 2000

This paper is described the development of on-line partial discharge detector for high voltage apparatus. This detector consists of acoustic and high frequency current sensors, amplifier part, A/D converter part, data communication part and computer. The contents of paper are characteristics of units and digital signal processing for reducing noise in partial discharge detection. We seek methods to do good digital signal processing for detection of partial discharge. We apply digital filtering methods to the elect Tic signal and a cross con-elation to the acoustic signal. This paper shows the characteristics of these filtering method and cross con-elation in partial discharge detection.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.27 no.3
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• pp.174-178
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• 2015

This paper describes a signal processing technique for identifying signals from defects by using an electromagnetic-ultrasonic guided waves method based on a magnetostrictive sensor that generates a torsional mode (T(0, 1)). Because this technique is based on the digital filtering, the filtered signals provide information on the relationship between the cutoff frequency of band-pass filter and the characteristic of defect signals in heat exchange tubes. To verify the performance of the technique, artificial defects with various thickness reduction ration and shape were machined in titanium tubes, and digital filtering results are reported. The results show that digital filtering provides information to the identify shape of defects and the contact condition between the tube and support ring. Therefore, the proposed technique has good potential as a tool for evaluating the integrity of heat exchange tubes.

• Journal of Korea Society of Digital Industry and Information Management
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• v.11 no.1
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• pp.157-169
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• 2015

In digital marketing, means of public relations and marketing of enterprises are changing into marketing techniques of predictive analytics. A significant study can be carried out by an analysis of 'the patterns of customers' uses' using big data on major portal sites and SNSs and their correlation with related keywords. This study analyzes the origins of mythological characters in major brands such as Nike, Hermes, Versace, Canon and Starbucks. Also, it extracts related keywords and relevance using big data on portal sites and SNS and their correlation. Nike marketing that reminds people of 'the goddess of victory, Nike' formed a good combination of the brand with relevance. Most of them are based on Greek mythology and have rich materials for storytelling and artistic values in common. Hopefully, this case analysis of foreign brands would become a starting point of discovering the materials of the domestic mythological characters.

• Journal of Korea Multimedia Society
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• v.23 no.4
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• pp.549-557
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• 2020

Chinese is the most spoken language in the world. However, because Chinese is a hieroglyphic language, using Chinese in a digital environment is very inconvenient. Chinese users are using Pinyin for Chinese input, but the phonetic representation of the Latin alphabet is not good. Hunminjeongeum has an excellent phonetic representation which can improve Chinese usage in digital environment. Therefore, it is possible to improve the use of Chinese by Chinese users in digital environment and to help Korean users who are learning Chinese. Therefore, this paper proposes a Chinese input method using Hunminjeongeum. In addition, we develop an input software using this input method and verify its effectiveness by evaluating usability.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2001.05a
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• pp.629-632
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• 2001

In this paper, We compared with advantage and disadvantage about several wavelet-basis watermarking techniques for digital image. Watermarking is embedding a digital signal called as 'watermark' into images to claim the ownership. In this study, simulation performed using wavelet based method among the various watermarking techniques proposed on domestic and foreign country. The experimental results show that the efficiency watermarking techniques among the proposed various techniques with good quality and robustness property.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1996.11a
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• pp.346-350
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• 1996

In optical disk drives, one of commonly used pickup actuator is a Sliding and rotary type of pickup actuator which is cheaper than other pickup actuators and has simple assembly. However, it reported that non-linearity due to friction between a shaft and a sleeve had to be considerably analyzed in design and servo system in employing this type of pickup actuator. In this paper, this friction is modeled as a Coulomb's friction and the effect of friction is examined in the simulation. A digital servo system is applied to pickup actuator with friction in order to have good focusing servo. To enhance focusing servo performance using digital servo merit, frist PD-controller is applied to have fast response performance, second lead-lag compensator is applied to have stable focusing performance.

• Progress in Superconductivity
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• v.9 no.2
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• pp.157-161
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• 2008

Due to high speed operations and ultra low power consumptions RSFQ logic circuit is a very good candidate for future electronic device. The focus of the RSFQ circuit development has been on the advancement of analog-to-digital converters and microprocessors. Recent works on RSFQ ALU development showed the successful operation of an 1-bit block of ALU at 40 GHz. Recently, the study of an RSFQ analog-to-digital converter has been extended to the development of a single chip RF digital receiver. Compared to the voltage logic circuits, RSFQ circuits operate based on the pulse logic. This naturally leads the circuit structure of RSFQ circuit to be pipelined. Delay time on each pipelined stage determines the ultimate operating speed of the circuit. In simulations, a two junction Josephson transmission line's delay time was about 10 ps, a splitter's 14.5 ps, a switch's 13 ps, a half adder's 67 ps. Optimization of the 4-bit ALU circuit has been made with delay time consideration to operate comfortably at 10 GHz or above.

• Proceedings of the KIEE Conference
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• 1987.11a
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• pp.355-358
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• 1987

A design of digital position control system with DC Motor is presented. The digital position control system is constructed by power circuits, interface circuits and control circuits using single chip microprocessor (8096). All control functions are implemented on the 16 bit micro-processor requiring only on incremental encoder for speed and position sensing. The control schemes are used by the proportional control for some modifications and braking algorithms. This digital position system offered to the fast response, good steady-state accuracy, flexibility and reliability, Hardware, software features and experimental results of this system are described.

• Journal of Advanced Marine Engineering and Technology
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• v.10 no.1
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• pp.51-64
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• 1986

Recently, being due to development of a small microprocessor, microprocessor have found increasing application as a digital controller in the control system. In this paper, authors analyze theoretically the continuous PID controller of a position control system with servomotor, and program the microprocessor as digital PID controller by an assembly language, and search the optimal parameters of the digital PID controller which make the smallest integral square error criterion for a performance criterion, and take experiment the indicial responses with optimal parameter. The results are following. 1) PD- behavior controller was better than P-behavior controller. 2) The smaller the smapling times of P-behavior controller and PD-behavior controller were, the better the indicial responses of the discrete system were. 3) Using a small microprocessor could replace the traditional continuous PID controller for good control.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.32A no.7
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• pp.36-42
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• 1995

In this paper, the CAD program for designing the microwave waveguide narrow-band bandpass filters has been developed by the passband correction method with filter synthesis for the MDR(Microwave Digital Relay) system. Here, the modified double E-plane structures are employed in the filter structure which is analyzed by the variational method. Using the developed CAD program, 0.01dB equi-ripple chebyshev type 6-section bandpass filters used in the MDR system operating nationally is designed at the center frequency of 11.0GHz, fabricated with tunable type and then measured by tuning process. The experimantal results show good agreements with the theoretical results.