Browsing by Author "Chen, Wen-Yu"

Now showing 1 - 3 of 3

DESIGN AND IMPLEMENTATION OF A HIGH ACCURACY INTERPOLATION ENCODER IC FOR MAGNETIC SENSOR
(2019-01-01)
Chen, Wen-Yu
;
Zhang, Yi-Feng
;
Chao, Paul C. -P.
;
Pribadi, Eka Fitrah
;
電機資訊學士班
The magnetic encoder (ME) always employs sensor passing through periodic and equal distance grating and then generates periodic quadrature scaling signals for displacement measurement. The phase is relative to the movement. To improve encoder accuracy or resolution, electronic interpolation technique had been developed to subdivide the phase of quadrature scaling signals. According to the trends, this paper proposed a specific method with excellent noise immunity characteristic and a complete calibration process to improve the accuracy of the system. The designed circuit is taped-out using TSMC 0.18-mu m CMOS process, where the active area is 1643 mu m x 1676 mu m. The chip has the specification of3.3 V supply voltage, 20 MHz clock frequency, and 0.0859 mW power consumption. The accuracy of the measurement system is 1.065um.
Design and implementation of a new high-accuracy interpolation encoder IC for magneto-resistive sensors
(1970-01-01)
Chen, Wen-Yu
;
Chang, I-Feng
;
Chao, Paul C-P
;
Thakur, Smriti
;
Tu, Tse-Yi
A new algorithm named the eight-section (ES) method for carrying out the interpolation for a magneto-resistive (MR) encoder is successfully developed and fabricated in a digital chip. It is known that a conventional magneto-resistive (MR) encoder employs the interpolation method, which converts incoming front-end analog signals in harmonics in sinusoids/co-sinusoids to moving displacement via calculating arc-tangents. This conventional interpolation requires divisions to be carried out for the displacement, which often leads to large noises while conducting digital computation, eventually undermining significantly the accuracy of the MR sensor. The proposed interpolation of eight-section (ES) is designed specially without divisions in the digital computation, leading to higher precision than the conventional interpolation conducting the computation of arc-tangents. The digital computation chip designed by this study consists of a cycle counter, two decimators for incoming analog signals of the MR sensor, a correcting circuit, and the proposal ES interpolation unit. The designed chip is successfully fabricated by TSMC 0.18-mu m CMOS process, the area of which is 1643 x 1676 mu m. The chip is than calibrated by a reference interferometer by experiments for further improving the measurement accuracy. The precision finally results in measuring displacement reaches as accurate as within 1.065 mu m, which is much favorable to the existing performance around 2 mu m by the conventional interpolation.
Pharmacophore anchor models of flaviviral NS3 proteases lead to drug repurposing for DENV infection
(2017-12-28)
Pathak, Nikhil
;
Lai, Mei-Ling
;
Chen, Wen-Yu
;
Hsieh, Betty-Wu
;
Yu, Guann-Yi
Background: Viruses of the flaviviridae family are responsible for some of the major infectious viral diseases around the world and there is an urgent need for drug development for these diseases. Most of the virtual screening methods in flaviviral drug discovery suffer from a low hit rate, strain-specific efficacy differences, and susceptibility to resistance. It is because they often fail to capture the key pharmacological features of the target active site critical for protein function inhibition. So in our current work, for the flaviviral NS3 protease, we summarized the pharmacophore features at the protease active site as anchors (subsite-moiety interactions). Results: For each of the four flaviviral NS3 proteases (i.e., HCV, DENV, WNV, and JEV), the anchors were obtained and summarized into 'Pharmacophore anchor (PA) models'. To capture the conserved pharmacophore anchors across these proteases, were merged the four PA models. We identified five consensus core anchors (CEH1, CH3, CH7, CV1, CV3) in all PA models, represented as the "Core pharmacophore anchor (CPA) model" and also identified specific anchors unique to the PA models. Our PA/CPA models complied with 89 known NS3 protease inhibitors. Furthermore, we proposed an integrated anchor-based screening method using the anchors from our models for discovering inhibitors. This method was applied on the DENV NS3 protease to screen FDA drugs discovering boceprevir, telaprevir and asunaprevir as promising anti-DENV candidates. Experimental testing against DV2-NGC virus by in-vitro plaque assays showed that asunaprevir and telaprevir inhibited viral replication with EC50 values of 10.4 mu M & 24.5 mu M respectively. The structure-anchor-activity relationships (SAAR) showed that our PA/CPA model anchors explained the observed in-vitro activities of the candidates. Also, we observed that the CEH1 anchor engagement was critical for the activities of telaprevir and asunaprevir while the extent of inhibitor anchor occupation guided their efficacies. Conclusion: These results validate our NS3 protease PA/CPA models, anchors and the integrated anchor-based screening method to be useful in inhibitor discovery and lead optimization, thus accelerating flaviviral drug discovery.