• Journal of the Institute of Electronics Engineers of Korea SC
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• v.40 no.3
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• pp.117-126
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• 2003

This paper proposes a real-time application of Walsh functions which is based on the on-line Walsh transformation and on-line Walsh function's differential operation. In the existing method of orthogonal functions, a major disadvantage is that process signals need to be recorded prior to obtaining their expansions. This paper proposes a novel method of Walsh transformation to overcome this shortcoming. And the proposed method apply to the unknown inputs observer(UIO) design for linear time-invariant dynamical systems

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.29 no.5
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• pp.344-352
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• 2018

We herein propose a calibration method for a sampling oscilloscope. The proposed method can correct the systematic errors in the oscilloscope such as time-based distortion and impedance mismatch. In addition, it can accurately estimate the residual jitter that remains after a time-based correction and the scale factor that varies in accordance with the setting of the pulse generator. The proposed method is validated thorough the comparison and verification with the power meter, and the uncertainty of the measurement method is analyzed.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.42 no.1
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• pp.82-89
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• 2014

This paper discusses the methods for reducing the sampling time quantization errors of the body dither type ring laser gyroscope. A ring laser gyroscope has the angle quantization error which is generated by the frequency counting method of the laser beat signal and sampling time quantization error which is generated by the demodulation method for eliminating the body dithering in which the sampling periods are fitted to the dither periods. Generally, because the dither periods are longer than the calculation periods of the inertial navigation system, vehicle navigation errors are produced by long time attitude update missing during the vehicle move with a high dynamical motion. In this paper, the double demodulation method is proposed for reducing the sampling time quantization error and its effects under the dynamic situation are confirmed by simulation.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.41 no.3
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• pp.31-38
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• 2004

The wavelength variation of a scanned fiber laser is analyzed using quadrature sampling technique. By time delayed sampling of a phase modulated Mach-Zender interferometer, the wavelength information can be precisely determined regardless of the nonlinearity in the Fabry-Perot wavelength filter which scanned the fiber laser. A wavelength readout resolution of ～20 pm was obtained at 2 KHz M-Z modulation frequency, and it was shown that the resolution could be improved in case of using an electro-optic phase modulator.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• fall
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• pp.78-79
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• 2021

본 논문에서는 시간 영역 오토인코더의 성능 개선을 위한 다중 대역 손실 함수를 제안한다. 기존의 시간 영역 오토인코더를 사용하는 압축 및 복원 모델은 저 대역 손실에 치중되어 고 대역 신호를 생성하지 못하고 다운 샘플링된 신호를 결과로 출력하는 문제점을 가진다. 이를 해결하기 위해 대역별로 손실을 분리하여 가중치를 조절할 수 있는 다중 대역 손실 함수를 제안한다. 제안하는 손실 함수가 적용된 오토인코더에 음성 신호를 입력하여 학습을 진행한 결과, 다운 샘플링이 발생하지 않으며 고 대역 신호가 복원되는 것을 스펙트로그램을 통해 확인하였다.

• Nuclear Engineering and Technology
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• v.27 no.1
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• pp.8-17
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• 1995

A great effort has been made to improve the nuclear plant control system by use of digital technologies, and a long term schedule for the control system upgrade has been prepared with an aim to implementation in the next generation nuclear plane. In case of digital control system, it is important to decide the sampling period for analysis and design of the system, because the performance and the stability of a digital control system depend on the value of the sampling period of the digital control system. There is, however, currently no systematic method used universally for determining the sampling period of the digital control system. Generally, a traditional way to select the sampling frequency is to use 20 to 30 times the bandwidth of the analog control system which has the same system configuration and parameters as the digital one. In this paper, a new method to select the sampling period is suggested which takes into account of the performance as well as the stability of the digital control system. By use of the frying's model of steam generator, the optimal sampling period of an assumptive digital control system for steam generator level control is estimated and is actually verified in the digital control simulation system for KORI-2 nuclear power plant steam generator level control. Consequently, we conclude the optimal sampling period of the digital control system for KORI-2 nuclear power plant steam generator level control is 1 second for all power ranges.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.10
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• pp.531-538
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• 2017

In the case of hydraulic pressure type fuse, we accept or reject certain product lots by considering the number of defective products in the operating pressure test. Generally, this procedure, known as 'The inspection by attributes', has been most commonly used in the field of quality assurance of products. However, the method of inspection by attributes suffers because it tests more samples than inspection by variables. Even though the quality of the products has remained stable in the process condition, the same number of samples is required for every lot, which wastes time and money. This paper suggests that the lot acceptance procedure is changed from inspection by attributes to inspection by variables. We can calculate the statistical tolerance percent of defectives and compare this to the Acceptable Quality Level (AQL) in order to save money and time. It is also easier to monitor and control the quality of products by using the process capability index and x-bar charts. In conclusion, the procedure delivers mutual benefit to both the customer and the producer by securing high quality products and reference data.

• Journal of Korea Multimedia Society
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• v.10 no.3
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• pp.316-324
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• 2007

Maximum Intensity Projection (MIP) identifies patients' anatomical structures from MR or CT data sets. Recently, it becomes possible to generate MIP images with interactive speed by exploiting Graphics Processing Unit (GPU) even in large volume data sets. Generally, volume boundary plane is obliquely crossed with view-aligned texture plane in hardware-texture based volume rendering. Since the ray sampling distance is not increased at volume boundary in volume rendering, the aliasing problem occurs due to data loss. In this paper, we propose an efficient method to overcome this problem by Re-rendering volume boundary planes. Our method improves image quality to make dense distances between samples near volume boundary which is a high frequency area. Since it is only 6 clipping planes are additionally needed for Re-rendering, high quality rendering can be performed without sacrificing computational efficiency. Furthermore, our method couldbe applied to Minimum Intensity Projection (MinIP) volume rendering.

• The Journal of the Korea Contents Association
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• v.13 no.4
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• pp.53-63
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• 2013

This paper presents an importance sampling(IS) embedded experimental frame(EF) design for efficient Monte Carlo (MC) simulation. To achieve IS principles, the proposed EF contains two embedded sub-models, which are classified into Importance Sampler(IS) and Bias Compensator(BC) models. The IS and BC models stand between the existing system model and EF, which leads to enhancement of model reusability. Furthermore, the proposed EF enables to achieve fast stochastic simulation as compared with the crude MC technique. From the abstract two case studies with the utilization of the proposed EF, we can gain interesting experimental results regarding remarkable enhancement of simulation performance. Finally, we expect that this work will serve various content areas for enhancing simulation performance, and besides, it will be utilized as a tool to understand and analyze social phenomena.

• Journal of the Korea Society for Simulation
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• v.16 no.3
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• pp.57-63
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• 2007

In real time rendering of fetus the empty space leaping while traversing a ray is most frequently used accelerating technique. The main idea is to skip empty voxel samples which do not contribute the result image and it speeds up the rendering time by avoiding sampling data while traversing a ray in the empty region, saving a substantial number of interpolations. Calculating the distance from the nearest object boundary for every yokel can reduce the sampling operation. Among widely-well-known distance maps, those estimates the true distance, such as euclidean distance, takes a long time to compute because of the complicated floating-point operations, and others which uses approximated distance functions, such as city-block and chessboard, provides faster computation time but sampling error may can occur. In this paper, therefore, we analyze the characteristics of several distance maps and compare the number of samples and rendering time. And we aim to suggest the most appropriate distance map for rendering of fetus in ultrasound image.