• 대한전자공학회:학술대회논문집
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• 대한전자공학회 1999년도 추계종합학술대회 논문집
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• pp.63-66
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• 1999

Echo and near-end crosstalk(NEXT) can be generated in two-wire duplex transmission. In this paper investigates how to cancel echoes of high speed communication. A pipeline algorithm is used to remove the echoes that high speed communication. It is least mean squared(LMS) algorithm based on the relaxed look-ahead concept, is focused on the pipelined LMS, and its performance is compared to that of the serial LMS algorithm. And we design pipelined adaptive filtering. In advanced of the hardware implementation with VHDL code the performance of pipelined LMS algorithm is verified by the computer simulation.

• 센서학회지
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• 제21권1호
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• pp.68-74
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• 2012

In this paper, Frequency Domain Mode Locked(FDML) wavelength swept laser with 55.027 kHz sweeping speed and 125 nm sweeping range has realized, and also a new method for recalibrating a nonlinear frequency sweeping of a swept laser has proposed. The Swept Source-Optical Coherence Tomography system using the proposed method has performed. For a mirror surface, the system showed the very clean 2-dimensional image and the advanced image speed of 7 frames per sec compared to the previous recalibration method.

• International journal of advanced smart convergence
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• 제13권3호
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• pp.48-58
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• 2024

Fiber to the Home (FTTH) technology is among the most advanced broadband services, delivering voice, data, and television through a single optical fiber directly to customer premises, ensuring high-speed and reliable connectivity. The study conducted on Nepal Telecom's FTTH networks involved direct measurements from the optical line terminal to the fiber access point and optical network unit, providing detailed insights into network performance. Using the OptiSystem software, the analysis revealed a link loss of 24.99 dB, a Q-factor of 12.98, and a minimum Bit Error Rate (BER) of 7.31E-39, all within standard limits, which underscores the robustness of the network. The study also identified that the highest contributors to signal loss were connector loss, fiber attenuation, and fusion splices, emphasizing the importance of minimizing these factors to maintain optimal network performance. Overall, these findings highlight the critical aspects of FTTH network design and maintenance, ensuring that service providers can deliver high-quality broadband services to customers.

• 대한의용생체공학회:의공학회지
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• 제43권6호
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• pp.417-423
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• 2022

The present study proposed a new interface system for capsule endoscopy by using head mounted display (HMD) device, which can control the orientation of the capsule endoscope with electromagnetic actuator (EMA) system. The orientation information of the HMD user was detected by the gyroscope sensor built into the device and then calculated to as an angle increment using Unity Engine compiler. The measured angle changes from the HMD were converted to the current values of the corresponding coils to be changed in the EMA system. Two experiments were designed to measure the accuracy and the intuitiveness of the HMD interface system. In the angle accuracy measurement, the capsule endoscope driven by HMD interface system showed the averaged errors of 0.68 degrees horizontally and 1.001 degrees vertically for given test angles. In the intuitiveness measurement, HMD interface system showed 1.33 times faster manipulation speed rather than the joystick interface system. In this respect, the HMD interface system for capsule endoscopy was expected to improve the overall diagnostic environment while maintaining comfort of patients and clinicians.

• 한국의학물리학회:학술대회논문집
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• 한국의학물리학회 2002년도 Proceedings
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• pp.468-470
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• 2002

We have designed X-ray detection system and multi-channel data acquisition system for Spiral CT application. X-ray detection system consists of scintillator and photodiode. Scintillator converts X-ray into visible light. Photodiode converts visible light into electrical signal. The multi-channel data acquisition system consists of analog, digital, master and backplane board. Analog board detects electrical signal and amplifies signal by 140dB. Digital board consists of MUX(Multiplex) which routes multi-channel analog signal to preamplifier, and ADC(Analog to Digital Converter) which converts analog signal into digital signal. Master board supplies the synchronized clock and transmits the digital data to image reconstructor. Backplane provides electrical power, analog output and clock signal. The system converts the projected X-ray signal over the detector array with large gain, samples the data in each channel sequentially, and the sampled data are transmitted to host computer in a given time frame. To meet the timing limitation, this system is very flexible since it is implemented by FPGA(Field Programmable Gate Array). This system must have a high-speed operation with low noise and high SNR(signal to noise ratio), wide dynamic range to get a high resolution image.

• 한국컴퓨터정보학회:학술대회논문집
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• 한국컴퓨터정보학회 2018년도 제58차 하계학술대회논문집 26권2호
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• pp.445-448
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• 2018

본 논문에서는 데이터 이중화 저장시스템의 장애발생으로 인한 백업서버 데이터 손실을 보호하기 위해 무 손실 실시간 데이터 이중화 시스템 설계방안을 제안한다. 이는 원본서버의 데이터와 백업서버의 데이터가 특정 시점 T에서 100% 일치하지 않는 비동기 방식을 동기방식으로 해결하기 위한 시스템 설계 제안으로, 원본서버의 데이터 생성과 동시에 실시간 데이터 백업을 목적으로 한다. 이를 위해 전송단계에서 필요한 가장 빠른 압축인 LZ4 압축 알고리즘을 기반으로 Intel AVX 명령어를 사용하여 보다 압축속도를 증진시켜 실시간 시스템을 구축한다. 또한 전송 중 보안위협으로부터 보호하기 위해 Key 전달 기법과 AES 암호화 알고리즘에 대해 기술한다.

• Journal of KIEE
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• 제10권1호
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• pp.1-6
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• 2000

This paper represents the design of 3D endoscopic video system in order to improve visualization and enhance the ability of the surgeon to perform delicate endoscopic surgery. In comparison of the polarized and electric shutter-type stereo imaging system, The former is superior in terms of accuracy and performance speed for knot-tying and loop pass test. The result of experiments show that the proposed 3D endoscopy system has a wide viewing angle and zone which is necessary for multi-view and it has better image quality and stability of the optical performances than the electric shutter-type does.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2004년도 Proceedings of ISRS 2004
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• pp.35-38
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• 2004

We developed a Near Real-Time Validation System (NRVS) for the Level-2 Products of AQUA Satellite. AQUA satellite is the second largest project of Earth Observing System (EOS) mission of NASA. This satellite provides the information of water cycle of the entire earth with many different forms. Among its products, we have used five kinds of level-2 geophysical parameters containing rain rate, sea surface wind speed, skin surface temperature, atmospheric temperature profile, and atmospheric humidity profile. To use these products in a scientific purpose, reasonable quantification is indispensable. In this paper we explain the near real-time validation system process and its detail algorithm. Its simulation results are also analyzed in a quantitative way. As reference data set in-situ measured meteorological data which are periodically gathered and provided by the Korea Meteorological Administration (KMA) is processed. Not only site-specific analysis but also time-series analysis of the validation results are explained and detail algorithms are described.

• 한국컴퓨터정보학회논문지
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• 제26권12호
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• pp.143-150
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• 2021

최근 전력산업에서는 검침원에 의한 수기 검침에서 AMI(Advanced Metering Infrastructure)를 활용한 원격검침으로 변화가 일어나고 있다. 원격검침 인프라에서 발생하는 전력 데이터가 블록체인에 기록된다면 위변조 방지로 무결성이 보장되고, 데이터 공유가 투명해짐에 따라 새로운 비즈니스가 창출될 수 있다. 하지만 기존의 이더리움 블록체인은 처리속도의 한계로 인해 대량의 트랜잭션 처리에 적합하지 않다. 이에 대한 해결책으로 다양한 On/Off-Chain 솔루션들이 연구되고 있다. 본 논문에서는 대량의 전력 데이터를 블록체인에 저장하기 위한 해결책으로 데이터 샤드(Shard) 처리를 활용한 연계 인터페이스 서버를 제안한다. 데이터를 샤드 단위로 처리하는 기법을 적용하여 대량의 트랜잭션을 이더리움에 전송했을 때 데이터 누락률이 0%가 되고, 동시에 처리속도가 대략 9배 향상되는 것을 실험을 통해 검증하였다.

• KNOM Review
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• 제22권2호
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• pp.1-11
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• 2019

과학기술·연구개발체계의 패러다임은 기존 단독형 연구수행 형태에서 변화하여 관측과 실험에서 발생한 대용량 데이터를 고속 네트워크를 통해 연구현장에 송수신하고 저장하며, 이를 각 연구자 (기관)의 목적에 맞도록 활용하는 형태로 변화하고 있다. 네트워크형 첨단연구는 협업화, 공유화, 공용화, 글로벌화 하는 형태로 발전하고 있으며, 이를 위해 과학기술과 IT기술의 결합 뿐 아니라, 점점 거대화되는 데이터의 실시간 공유와 활용을 위해 최적화된 네트워크 환경과 기술 간의 융합이 필요하다. 본 논문에서는 국가과학기술연구망 (KREONET)의 네트워크형 첨단 연구의 사례를 통해 변화의 방향을 제시하고, 데이터흐름을 분석한다. 이를 통해 주요 데이터흐름과 용량에 따른 네트워크 최적화 모델을 제시하였으며, 네트워크형 첨단연구에서 요구되는 실시간성 연구수행 성능을 충족하였다.