• 한국광학회지
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• 제10권5호
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• pp.357-363
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• 1999

다중산란매질의 광학계수를 측정하기 위하여 광세기의 변화와 위상차이를 동시에 측정하는 주파수 영역 분광장치를 구성하고, 산란과 흡수가 다른 매질 조건하에서 진폭 변조된 광을 입사시킨 후 후방 산란광의 교류 및 위상지연 성분을 heterodyne 검지 방법을 이용하여 측정하였다. 실험을 통하여 산란자와 흡수체의 농도가 증가함에 따라 흡수계수와 수송산란 계수는 선형적으로 증가함을 확인할 수 있었으며, 흡수계수와 수송산란계수를 확산이론을 이용하여 구할 수 있었다. 광원과 검출기의 거리, 변조주파수에 따라 측정 가능한 광학계수의 범위를 분석하였다. 레이저 다이오드를 사용하는 소형화된 이 장치는 생체조직과 같은 다중 산란매질의 비침습적 광학계수 측정에 이용될수 있으리라 기대된다.

• 한국정보통신학회논문지
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• 제16권10호
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• pp.2163-2170
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• 2012

신호수신시스템은 수신신호의 주파수, 펄스변조, 스캔 변조, 펄스내 위상변조, 펄스내 주파수 변조 등 다양한 신호에 대한 측정 및 분석능력을 보유하여야 한다. 이러한 신호수신시스템의 성능을 평가하기 위하여 신호원들을 실험실 환경에서 효율적으로 모의발생하고 다수 전파가 존재하는 실제 운영환경과 유사한 복잡한 전파환경을 모의발생할 수 있는 효율적인 신호원 발생기를 제안한다. 제안한 모의전파신호원을 신호수신시스템 개발 전 과정에 걸쳐 활용할 경우 정확한 성능 검증 및 시험 비용을 절감할 수 있다.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2011년도 춘계학술대회
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• pp.310-312
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• 2011

복합 잡음 환경에서 원 신호의 음성이나 영상신호를 획득하거나, 전송 및 저장을 위해서 디지털필터가 사용되고 있다. 디지털필터는 크게 FIR 필터와 IIR 필터로 나눌 수 있다. FIR 필터 중에서 창함수는 선형위상의 특성을 가지고 있고 손쉽게 통과대역, 차단주파수 등을 설정할 수 있다. 본 논문에서는 기존의 창함수를 변형하여 설계한 후 필터 특성을 확인하기 위해 Peak side-lobe와 주파수 천이특성 등을 사용하여 기존의 방법들과 비교하였다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제12권10호
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• pp.4873-4888
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• 2018

A joint blind parameter estimation algorithm based on minimum channel stability function aimed at the non-cooperative high-order modulated paired carrier multiple access (PCMA) signals is proposed. The method, which uses hierarchical search to estimate time delay, amplitude and frequency offset and the estimation of phase offset, including finite ambiguity, is presented simultaneously based on the derivation of the channel stability function. In this work, the structure of hierarchical iterative processing is used to enhance the performance of the algorithm, and the improved algorithm is used to reduce complexity. Compared with existing data-aided algorithms, this algorithm does not require a priori information. Therefore, it has significant advantage in solving the problem of blind parameter estimation of non-cooperative high-order modulated PCMA signals. Simulation results show the performance of the proposed algorithm is similar to the modified Cramer-Rao bound (MCRB) when the signal-to-noise ratio is larger than 16 dB. The simulation results also verify the practicality of the proposed algorithm.

• Asian Pacific Journal of Cancer Prevention
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• 제14권11호
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• pp.6653-6656
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• 2013

Background: The single most common proto-oncogene change in human neoplasms is a point mutation in RAS genes. A wide range of variation in frequency of KRAS mutations has been seen in hematologic malignancies. Despite this, RAS roles in leukemogenesis remain unclear. The frequency of KRAS mutations in CML has been reported to be between zero an 10%. Many attempts have been done to develop an anti-RAS drug as a therapeutic target. Materials and Methods: This cross sectional study was performed in Mashhad University of Medical Sciences, Mashhad, Iran from 2010-2012. In 78 CML patients (diagnosed according to WHO 2008 criteria) in chronic or accelerated phases, KRAS mutations in codons 12 and 13 were analyzed using a modified PCR-restriction fragment length polymorphism (RFLP) method. Results: We did not detect any KRAS mutations in this study. Conclusions: KRAS mutations are overall rare in early phase CML and might be secondary events happening late in leukemogenesis cooperating with initial genetic lesions.

• 한국운동역학회지
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• 제28권3호
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• pp.159-164
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• 2018

Objective: The aims of this study were to determine the impact peak force and kinematic variables in running speed and investigate the relationship between them. Method: Thirty-nine male heel strike runners ($mean\;age=21.7{\pm}1.6y$, $mean\;mass=72.5{\pm}8.7kg$, $mean\;height=176.6{\pm}6.1cm$) were recruited in this investigation. The impact peak forces during treadmill running were assessed, and the kinematic variables were computed using three-dimensional data collected using eight infrared cameras (Oqus 300, Qualisys, Sweden). One-way analysis of variance ANOVAwas used to investigate the influence of the running speed on the parameters, and Pearson's partial correlation was used to investigate the relationship between the impact peak force and kinematic variables. Results: The running speed affected the impact peak force, stride length, stride frequency, and kinematic variables during the stride phase and the foot angle at heel contact; however, it did not affect the ankle and knee joint angles in the sagittal plane at heel contact. No significant correlation was noted between the impact peak force and kinematic variables in constantrunning speed. Conclusion: Increasing ankle and knee joint angles at heel contact may not be related to the mechanism behind reducing the impact peak force during treadmill running at constant speed.

• 전자공학회논문지A
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• 제33A권11호
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• pp.1-9
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• 1996

In the following paper, new architectural algorithm of clock and data recovery circuit is proposed for 622.08 Mbps optical communication receiver. New algorithm makes use of charge pump PLL using voltage controlled ring oscillator and extracts 8-channel 77.76 MHz clock signals, which are delayed by i/8 (i=1,2, ...8), to convert and recover 8-channel parallel data from 662.08 Mbps MRZ serial data. This circuit includes clock genration block to produce clock signals continuously even if input data doesn't exist. And synchronization of data and clock is doen by the method which compares 1/2 bit delayed onput data and decided dta by extracted clock signals. Thus, we can stabilize frequency and phase of clock signal even if input data is distorted or doesn't exist and simplify receiver architecture compared to traditional receiver's. Also it is possible ot realize clock extraction, data decision and conversion simulataneously. Verification of this algorithm is executed by DESIGN CENTER (version 6.1) using test models which are modelized by analog behavior modeling and digital circuit model, modified to process input frequency sufficiently, in SPICE.

• Smart Structures and Systems
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• 제26권5호
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• pp.667-680
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• 2020

This study aims at reporting a systematic procedure for evaluating the static and dynamic structural performance of steel bridges based on a short-period structural health monitoring measurement. Sungsu bridge located in Korea is considered as a case study presenting the most recent tests carried out to examine the bridge condition. Short-period measurements of Structural Health Monitoring (SHM) system were used during the bridge testing phase. A novel symmetry index is introduced using statistical analyses of deflection and strain measurements. Frequency Domain Decomposition (FDD) is implemented to the strain measurements to estimate the bridge mode shapes and damping ratios. Furthermore, Markov Chain Monte Carlo (MCMC) is also implemented to examine the reliability of bridge performance while ambient design trucks are in static or moving at different speeds. Strain, displacement and acceleration were measured at selected locations on the bridge. The results show that the symmetry index can be an efficient and useful measure in assessing the steel bridge performance. The results from the used method reveal that the performance of the Sungsu bridge is safe under operational conditions.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 추계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.204-206
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• 2002

For small capacity rectifier circuits such as these for consumer electronics and appliances. capacitor input type rectifier circuits are generally used Consequently. various harmonics generated within the power system become a serious Problem. Various studies of this effect have been presented previously. However. most of these employ switching devices, such as FETs and the like. The absence of switching devices makes systems more tolerant to over -load, and brings low radio noise benefits. We propose a power factor correction scheme using a LC resonant in commercial frequency without switching devices. In this method. It makes a sinusoidal wave by widening conduction period using the current resonance in commercial frequency. Hence, the harmonic characteristics can be significantly improved. where the lower order harmonics. such as the fifth and seventh orders are much reduced. The result are confirmed by the theoretical and expermental implementations.

• 산업기술연구
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• 제20권B호
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• pp.155-162
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• 2000

Although Fuzzy Logic Controller(FLC) adopted three terms as input gives better performance, FLC is in general composed of two-term control because of the difficulty in the construction of fuzzy rule base. In this paper, a three-term FLC which is similar to PID control but acts as a nonlinear controller is proposed. To reduce the complexity of the rule base design and to increase efficiency. a simplified fuzzy PID control is induced from a hybrid velocity/position type PID algorithm by sharing a common rule base for both fuzzy PI and fuzzy PD parts. It is simple in structure, easy in implementation, and fast in calculation. The phase plane technique is applied to obtain the rule base for fuzzy two-term control and the resultant rule base is Macvicar-Whelan type. And the membership function is a Gaussian function. The frequency response information is used in tuning of the membership functions. Also a tuning strategy for the scaling factors is proposed based on the relationship between PID gain and the scaling factors. Simulation results show better performance and the effectiveness of the proposed method.