• Journal of Life Science
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• 제11권2호
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• pp.94-98
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• 2001

Type I signal peptidase cleaves the signal sequence from the amino terminus of membrane and secreted proteins afters these protein insert across the membrane. This enzyme serves as a potential target for the development of novel antibacterial agents due to its unique physiological and biochemical properties. Despite considerable research, the signal peptidase assay still remains improvement to provide further understanding of the mechanism and high-throughput inhibitor screening of this enzyme. In this paper, three known signal peptidase assays are tested with an E. coli D276A mutant signal peptidase to distinguish the sensitivity of each assays. In vitro assay using the procoat synthesized by in vitro transcription translation shows that the D276A signal peptidase I was inactive while in vivo processing of pro-OmpA expressed in the temperature-sensitive E. coli strain IT41 as well as in vitro assay using pro-OmpA nuclease A substrate show that D276A signal peptidase I has activity like wild-type signal peptidase. These results suggest that in vitro assay using the pro-OmpA nuclease A and in vivo pro-OmpA processing assay are more sensitive monitors than in vitro assay using the pro-coat. In conculsion, caution should be used when interpreting the in vitro results using the procoat.

• 대한의용생체공학회:의공학회지
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• 제17권3호
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• pp.319-326
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• 1996

Clinical myography(EMG) is a technique for diagnosing neuromuscular disorders by analyzing the electrical signal that can be records by needle electrode during a muscular contraction. The EMG signal arises from electrical discharges that accompany the generation of force by groups of muscular fiber, and the analysis of EMG signal provides symptoms that can distinguish disorder of mLecle from disor- ders of nerve. One of the methods for analysis of EMG signal is to separate the individual discharge-the motor unit action potentials(MVAPS) - from EMG signal. But we can only observe the EMG signal that is a superimposed version of time delayed MUAPS. To obtain the information about MUAP(, i.e., position, firing number, magnitude etc), first of all, a method that can separate each MUAP from the EMG signal must be developed Although the methods for MUAP separation have been proposed by many researcherl they have required heavy computational burden. In this paper, we proposed a new method that has less computational burden and performs more reliable separation of superimposed EMG signal using wavelet filter which has multiresolution analysis as major property. As a result, we develope the separation algorithm of superimposed EMG signal which has less computational burden than any other researchers and exacutes exact separation process. The performance of this method has been discussed in the automatic resolving procedure which is neccessary to identify every firing of every motor unit from the EMG pattern.

• ETRI Journal
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• 제37권6호
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• pp.1120-1128
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• 2015

We propose a pseudo optical N-level pulse-amplitude modulation (PO PAM-N) signal using a few externally-modulated lasers (EMLs) operating at different wavelengths, which is suitable for upgrading the transmission speed over an optical link of < 10 km single-mode fiber with low-cost components. To compare a PO PAM-N signal with that of a standard optical PAM-N signal, we perform experiments for evaluating the performance of a 51.56-Gb/s PO PAM-4 signal and standard 51.56-Gb/s optical PAM-4 signal. The receiver sensitivity (at $BER=10^{-5}$) of the PO PAM-4 signal is 1.5 dB better than the receiver sensitivity of a standard optical PAM-4 signal. We also investigate the feasibility of PO PAM-N (N = 4, 8, and 16) signals operating at 103.12 Gb/s, considering relative intensity noise, timing jitter, extinction ratio (ER) of EMLs, and dispersion. From the results, a PO PAM-8 signal performs better than PO PAM-4 and PO PAM-16 signals at 103.12 Gb/s. Finally, we suggest a timing control method to suppress the effect of dispersion in a PO PAM-N signal. We show that the tolerance to dispersion of a 103.12-Gb/s PO PAM-8 signal can be improved to ${\pm}40ps/nm$ by applying a proposed scheme.

• 한국통신학회논문지
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• 제38A권4호
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• pp.318-324
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• 2013

블라인드 채널 등화 시 신호 추정의 신뢰도는 등화기의 수렴 속도와 정상상태 성능을 결정한다. 그러므로 신호 추정에 사용되는 비선형 추정기와 기준 신호가 적절히 선택되어야 한다. 이 논문에서는 신호 추정의 신뢰도를 높이기 위해 신호 추정에 성긴 신호점과 촘촘한 신호점을 각각 적용하여 두 오차를 구하고, 두 오차의 상대적 신뢰도를 산출, 이를 활용하여 등화기를 차등적으로 적응시켰다. 이때 두 오차를 번갈아 적용하여 두 동작 모드를 완만하게 결합하였다. 모의실험을 통하여 제안 방식이 기존 방식에 비해 빠른 과도상태 수렴과 낮은 정상상태 오차를 달성하는 것을 보였다.

• Nuclear Engineering and Technology
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• 제53권9호
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• pp.3122-3125
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• 2021

Electromagnetic vortex flowmeter is a new type of instrument for detecting leakage of steam generator, and the signal processing method based on the envelope to calculate energy ratio can effectively detect bubbles in sodium flow. The signal processing method is not affected by changes in the amplitude of the sensor output signal, which is caused by changes in magnetic field strength and other factors. However, the detection sensitivity of the electromagnetic vortex flowmeter is reduced. To this end, a signal processing method based on inverse Fourier transform to calculate energy ratio is proposed. According to the difference between the frequency band of the bubble noise signal and the flow signal, only the amplitude in the frequency band of the flow signal is retained in the frequency domain, and then the flow signal is obtained by the inverse Fourier transform method, thereby calculating the energy ratio. Using this method to process the experimental data, the results show that it can detect 0.1 g/s leak rate of water in the steam generator, and its performance is significantly better than that of the signal processing method based on the envelope to calculate energy ratio.

• Journal of Positioning, Navigation, and Timing
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• 제10권1호
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• pp.55-66
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• 2021

In this paper, we propose a signal propagation modeling technique for generating a positioning fingerprint DB based on Long Term Evolution (LTE) signals. When a DB is created based on the location-based signal information collected in an urban area, gaps in the DB due to uncollected areas occur. The spatial interpolation method for filling the gaps has limitations. In addition, the existing gap filling technique through signal propagation modeling does not reflect the signal attenuation characteristics according to directions occurring in urban areas by considering only the signal attenuation characteristics according to distance. To solve this problem, this paper proposes a Deep Neural Network (DNN)-based signal propagation functionalization technique that considers distance and direction together. To verify the performance of this technique, an experiment was conducted in Seocho-gu, Seoul. Based on the acquired signals, signal propagation characteristics were modeled for each method, and Root Mean Squared Errors (RMSE) was calculated using the verification data to perform comparative analysis. As a result, it was shown that the proposed technique is improved by about 4.284 dBm compared to the existing signal propagation model. Through this, it can be confirmed that the DNN-based signal propagation model proposed in this paper is excellent in performance, and it is expected that the positioning performance will be improved based on the fingerprint DB generated through it.

• 한국항만학회지
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• 제11권1호
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• pp.29-44
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• 1997

The purpose in this study was to review the travel characteristics of the left-turn signal system on the signalized intersections under the study in Pusan area, construct the appropriate transportation systems under the different left-turn signal system : Protected Left-Turn signal system, Permissive Left-Turn signal system, and Protected-Permissive Left-Turn signal system based upon the travel characteristics reviewed, and finally suggest the optimal left-turn signal system which could reduce traffic delay and fuel consumption. and also improve traffic safety on the signalized intersections based upon the optimal transportation system constructed. Based upon the results, it was concluded that the Protected-Permissive Left-Turn signal system would be better and safer than the Permissive Left-Turn signal system in the aspects which could reduce decrease delay and fuel consumption, and simultaneously increase traffic safety on the signalized intersections, even if the optimal Permissive Left Turn signal system was found to be the best left-turn signal system in the aspects of the Measures of Effectiveness(MOE) on the intersections under the study.

• Journal of Positioning, Navigation, and Timing
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• 제4권4호
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• pp.173-180
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• 2015

In this study, an algorithm that detects a spoofing signal for a GPS L1 signal was proposed, and the performance was verified through RF spoofing signal simulation. The proposed algorithm determines the reception of a spoofing signal by detecting a correlation distortion of GPS L1 C/A code caused by the spoofing signal. To detect the correlation distortion, a detection criterion of a spoofing signal was derived from the relationship among the Early, Prompt, and Late tap correlation values of a receiver correlator; and a detection threshold was calculated from the false alarm probability of spoofing signal detection. In this study, an RF spoofing environment was built using the GSS 8000 simulator (Spirent). For the RF spoofing signal generated from the simulator, the RF spoofing environment was verified using the commercial receiver DL-V3 (Novatel Inc.). To verify the performance of the proposed algorithm, the RF signal was stored as IF band data using a USRP signal collector (NI) so that the data could be processed by a CNU software receiver (software defined radio). For the performance of the proposed algorithm, results were obtained using the correlation value of the software receiver, and the performance was verified through the detection of a spoofing signal and the detection time of a spoofing signal.

• 한국ITS학회 논문지
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• 제5권1호
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• pp.21-30
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• 2006

중앙버스전용차로제가 도입됨에 따라 서울의 도로환경은 단기간에 급격하게 변하였으며, 이러한 급격한 변화에 미리 준비되지 못하였던 신호운영상의 문제점들이 경험되고 있다. 장 임계적인 문제점으로 중앙버스전용차로 설치구간 신호교차로에서 일반차량 좌회전 진행을 허용할 경우, 현재 우리나라가 규정하고 있는 차량 4색신호등의 한계로 인한 신호의 비효율적 운영이다. 중앙버스전용차로 설치구간 신호교차로에서 일반차량 좌회전의 현실적 운영방안 마련이 필요하다. 본 연구는 중앙차로전용신호의 도입을 준비하기 위하여 교통관제센터의 신호운영모드별 선행좌회전 및 후행좌회전 운영방안을 검토하고, 각 운영방안 별 Signal Map 구성방안을 점검한다. Signal Map 작성방안을 검토한 결과 기존의 신호제어 장비에 추가의 신호등기신호보드를 활용하는 방법으로 제안된 방법의 현장 적용이 용이한 것으로 확인되었다.

• 한국의류산업학회지
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• 제20권5호
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• pp.616-620
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• 2018

Recently, many researches have been conducted to improve the performance and wearability of smart wearables. In this study, we designed and fabricated the signal and power transmission textile cables for smart wearables which have excellent wearability, durability and reliability. For the signal transmission textile cables, conductive yarns for the signal line and the ground line were developed. Three types of signal transmission textile cables have been developed using the conductive yarns. Linear density, tensile properties, electrical resistance and RF characteristics were tested to characterize the physical and electrical properties of three signal transmission textile cables. The conductive yarns have the very low resistance of $0.05{\Omega}/cm$ and showed excellent uniformity of electric resistance. Therefore, the electrical resistance of the signal transmission fiber cable can be reduced by increasing the number of conductive yarns used in signal and ground lines. However, the radio frequency (RF) characteristics of the signal transmission textile cables were better as the number of strands of the conductive yarns used was smaller. This is because the smaller the number of strands of conductive yarn used in signal transmission textile cables, the narrower and more parallel the distance between the signal line and the ground line. It is expected that the signal and power transmission textile cable for signal and power transmission will be utilized in smart wearable products.