Browsing by Author "Chen, Kuan-Hung"

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A Region of Interest Selection for Vision-Based Respiratory Rate Measurement in Sleeping Scenario
(2020-01-01)
Wu, Bing-Fei
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Lin, Chun-Han
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Huang, Po-Wei
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Chen, Kuan-Hung
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He, Da-Hong
Vision-based respiratory measurement can remotely measure respiratory information without affecting the sleep quality of the user. However, several scenarios during sleeping, such as when blankets cover areas of the face or body, can be a challenge when estimate respiratory rate (RR) due to the uncertainty of the region of interest (ROI). In this study, we first investigate the metrics and physical meanings of ROI selection from the perspectives of array signal processing and the concept of linear combining. Then, we propose an ROI detection algorithm based on both temporal and spatial consistency (TSC), which aims to extract the representative characteristics of respiration with fewer computational resources. Furthermore, a sleeping database, containing more than 50 hours of data, was built to investigate the performance of benchmarked ROI methods during long-term sleeping. The experimental results demonstrate that TSC attains the highest signal-to-noise ratio (SNR) at 20.6 dB and a relatively low elapsed time of 100.2 frames per second (fps). For the RR estimation accuracy, TSC reduces the mean absolute error from 1.65 breaths per minute (bpm) to 0.97 bpm.
Correlation among photoluminescence and the electronic and atomic structures of Sr2SiO4:xEu(3+) phosphors: X-ray absorption and emission studies
(2020-07-29)
Zheng, Shi-Yan
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Chiou, Jau-Wern
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Li, Yueh-Han
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Yang, Cheng-Fu
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Ray, Sekhar Chandra
A series of Eu3+-activated strontium silicate phosphors, Sr2SiO4:xEu(3+) (SSO:xEu(3+), x=1.0, 2.0 and 5.0%), were synthesized by a sol-gel method, and their crystalline structures, photoluminescence (PL) behaviors, electronic/atomic structures and bandgap properties were studied. The correlation among these characteristics was further established. X-ray powder diffraction analysis revealed the formation of mixed orthorhombic alpha'-SSO and monoclinic beta-SSO phases of the SSO:xEu(3+) phosphors. When SSO:xEu(3+) phosphors are excited under ultraviolet (UV) light (lambda=250 nm,similar to 4.96 eV), they emit yellow (similar to 590 nm), orange (similar to 613 nm) and red (similar to 652 and 703 nm) PL bands. These PL emissions typically correspond to 4f-4f electronic transitions that involve the multiple excited D-5(0)-> F-7(J) levels (J=1, 2, 3 and 4) of Eu3+ activators in the host matrix. This mechanism of PL in the SSO:xEu(3+) phosphors is strongly related to the local electronic/atomic structures of the Eu3+-O2- associations and the bandgap of the host lattice, as verified by Sr K-edge and Eu L-3-edge X-ray absorption near-edge structure (XANES)/extended X-ray absorption fine structure, O K-edge XANES and K-alpha X-ray emission spectroscopy. In the synthesis of SSO:xEu(3+) phosphors, interstitial Eu2O3-like structures are observed in the host matrix that act as donors, providing electrons that are nonradiatively transferred from the Eu 5d and/or O 2p-Eu 4f/5d states (mostly the O 2p-Eu 5d states) to the D-5(0) levels, facilitating the recombination of electrons that have transitioned from the D-5(0) level to the F-7(J) level in the bandgap. This mechanism is primarily responsible for the enhancement of PL emissions in the SSO:xEu(3+) phosphors. This PL-related behavior indicates that SSO:xEu(3+) phosphors are good light-conversion phosphor candidates for use in near-UV chips and can be very effective in UV-based light-emitting diodes.
High Efficiency Data Access System Architecture for Deblocking Filter Supporting Multiple Video Coding Standards
(2012-05-01)
Chien, Cheng-An
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Jian, Guo-An
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Chang, Hsiu-Cheng
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Chen, Kuan-Hung
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Guo, Jiun-In
"This paper presents an efficient VLSI architecture of in-loop deblocking filter (ILF) with high efficiency data access system for supporting multiple video coding standards including H. 264 BP/MP/HP, SVC, MVC, AVS, and VC-1. Advanced standards, such as H. 264 MP/HP, SVC, and MVC, adopt Macro Block Adaptive Frame Field (MBAFF) to enhance coding efficiency which results in the performance bottleneck of deblocking filter due to complex data access requirement. This design challenge has not been discussed in previous works according to our best knowledge. Therefore, we develop a Prediction Data Management (PDM) to manage the input prediction data order of deblocking filter for different coding types (like frame/field) and multiple standards. We also design an extended output frame buffer module to solve the system bus architecture restriction (like 1K boundary and burst length) and achieve high efficiency data access by using MB-based scan order. By using these techniques, we can solve the data accessing design challenge and reduce 67% bus latency. After being implemented by using 90 nm CMOS technology, the proposed work can achieve real-time performance requirement of QFHD (3840x2160@30fps) when operated at 156MHz at the cost of 50.6K gates and 2.4K bytes local memory. The maximum operating frequency of the proposed design, i.e. 370MHz, is higher than the required real-time operating frequency so that voltage scaling may be adopted to reduce power consumption."
Land Subsidence in Chiayi, Taiwan, from Compaction Well, Leveling and ALOS/PALSAR: Aquaculture-Induced Relative Sea Level Rise
(2018-01-01)
Hung, Wei-Chia
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Hwang, Cheinway
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Chen, Yi-An
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Zhang, Lei
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Chen, Kuan-Hung
Chiayi County is located in the largest alluvial plain of Taiwan with extensive aquaculture and rice farming sustained by water extracted from groundwater wells. Chiayi is a typical aquaculture area affected by land subsidence, yet such lands worldwide combine to provide nearly 90% of global aquaculture products, greatly reducing oceanic overfishing problems. This study uses precision leveling, multi-layer compaction monitoring well (MLCW) and spaceborne SAR interferometry (InSAR) to examine the cause and effect of land subsidence in Chiayi associated with groundwater extractions and changes. Heights at benchmarks in a leveling network are measured annually and soil compactions at 24-26 layers up to 300-m depths at 7 MLCWs are collected at one-month intervals. Over 2007-2011, 15 ALOS/PALSAR images are processed by the method of TCPInSAR to produce subsidence rates. All sensors show that land subsidence occur in most parts of Chiayi, with rates reaching 4.5 cm/year around its coast, a result of groundwater pumping from shallow to deep aquifers. MLCWs detect mm-accuracy seasonal soil compactions coinciding with groundwater level fluctuations and causing dynamic compactions. Compactions near Taiwan High Speed Rail may reduce the strength of the rail's supporting columns to degrade its safety. The SAR images yield subsidence rates consistent with those from leveling and compaction wells after corrections for systematic errors by the leveling result. Subsidence in Chiayi's coastal area leads to relative sea level rises at rates up to 15 times larger than the global eustatic sea level rising rate, a risk typical for world's aquaculture-rich regions. At the fish pond-covered Budai Township, InSAR identifies subsidence spots not detected by leveling, providing crucial geo-information for a sustainable land management for aquaculture industry.
Remote Photoplethysmography Enhancement with Machine Leaning Methods
(2019-01-01)
Wu, Bing-Fei
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Huang, Po-Wei
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He, Da-Hong
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Lin, Chung-Han
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Chen, Kuan-Hung
Driver's physiological state is highly correlated to the traffic safety. An affordable and convenient way to monitor driver's physiological state is remote Photoplethysmography (rPPG). Earlier algorithms achieved high accuracy on measuring rPPG signals in stationary case. But in real cases, such as driving, rPPG signals might be corrupted with interference. To obtain higher Signal-to-Noise-Ratio (SNR) rPPG signals, three algorithms are proposed. The PCA spectral subtraction (PCA-SS) considers the spectrum of the environmental noise and utilizes the energy subtraction to reduce the noise. The machine learning methods, convolution autoencoder (CAE) and multi-channel convolution autoencoder (Multi-CAE), are adopted in order to enhance the rPPG signal. The test data we used are 187 videos recorded in stationary case, passenger case, and real driving situation. In driving situation, the Multi-CAE method, in comparison with the original method provided by W. Wang et al. [1] and G. De Haan et al. [2], achieves 33% & 35% reduction in MAE, RMSE respectively, and 11% improvement in success rate [3].
Short-Time Geodetic Determination of Aquifer Storage Coefficient in Taiwan
(2018-12-01)
Chen, Kuan-Hung
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Hwang, Cheinway
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Chang, Liang-Cheng
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Ke, Chien-Chung
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土木工程學系
Specific yield (S-y) and specific storage (S-s) are two hydrogeological parameters often estimated in a costly pumping test (hydraulic method). Pumping or a natural aquifer recession can cause gravity change and surface deformation, useful for S-y and S-s determination by the more economic geodetic method. From 2013 to 2017, over a few days we measured gravity changes at four sites and subsidence at one site in Taiwan by a FG5 gravimeter and a precision level to estimate S-y and S-s. Using short-time gravity and level records avoids complicated logistic supports and temporal effects. The measured gravity changes are associated with the MODFLOW-modeled groundwater depletion. We succeeded in estimating S-y at two sites and failed at the other two. One successful case uses rapid postrain declines of gravity and groundwater level. We did leveling only at one site, but here the 500-min, continuous, submillimeter subsidence records result in a S-s consistent with the hydraulic result. Lessons on the failed cases of S-y are suggested to avoid disrupting factors in gravity surveys. A semiautomatic leveling procedure is proposed to maximize the chance for S-s determination. Our simulations show that gravity changes increase with S-y and decrease with initial hydraulic head and horizontal gravimeter-pumping well distance, helping to predict if the gravity-based method works at a site and to best plan a gravity survey. Drilling data show that the S-y values from the hydraulic and geodetic methods represent aquifer storage coefficients over different aquifer layers. Plain Language Summary A pumping test extracts groundwater from a well to estimate an aquifers storage coefficients, based on measurements of the groundwater lowering rate during pumping. But pumping can also lower gravity values and deform the surface. After a heavy rain stops, the aquifer level can rapidly decline to lower gravity values. We measure such gravity changes and surface deformations to determine hydrogeological parameters critical to understanding aquifer storage capacity and managing groundwater resource.
Target-specific identification and characterization of the putative gene cluster for brasilinolide biosynthesis revealing the mechanistic insights and connic enzymes
(2016-01-01)
Chiu, Hsien-Tai
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Weng, Chien-Pao
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Lin, Yu-Chin
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Chen, Kuan-Hung
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生物科技學系
Brasilinolides exhibiting potent immunosuppressive and antifungal activities with remarkably low toxicity are structurally characterized by an unusual modified 2-deoxy-L-fucose (2dF) attached to a type I polyketide (PK-I) macrolactone. From the pathogenic producer Nocardia terpenica (Nocardia brasiliensis IFM-0406), a 210 kb genomic fragment was identified by target-specific degenerate primers and subsequently sequenced, revealing a giant nbr gene cluster harboring genes (nbrCDEF) required for TDP-2dF biosynthesis and those for PK-I biosynthesis, modification and regulation. The results showed that the genetic and domain arrangements of nbr PK-I synthases agreed colinearly with the PK-I structures of brasilinolides. Subsequent heterologous expression of nbrCDEF in Escherichia coli accomplished in vitro reconstitution of TDP-2dF biosynthesis. The catalytic functions and mechanisms of NbrCDEF enzymes were further characterized by systematic mix-and-match experiments. The enzymes were revealed to display remarkable substrate and partner promiscuity, leading to the establishment of in vitro hybrid deoxysugar biosynthetic pathways throughout an in situ one-pot (iSOP) method. This study represents the first demonstration of TDP-2dF biosynthesis at the enzyme and molecular levels, and provides new hope for expanding the structural diversity of brasilinolides by combinatorial biosynthesis.
Target-specific identification and characterization of the putative gene cluster for brasilinolide biosynthesis revealing the mechanistic insights and connic enzymes
(2016)
Chiu, Hsien-Tai
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Weng, Chien-Pao
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Lin, Yu-Chin
;
Chen, Kuan-Hung
;
生物科技學系
Brasilinolides exhibiting potent immunosuppressive and antifungal activities with remarkably low toxicity are structurally characterized by an unusual modified 2-deoxy-L-fucose (2dF) attached to a type I polyketide (PK-I) macrolactone. From the pathogenic producer Nocardia terpenica (Nocardia brasiliensis IFM-0406), a 210 kb genomic fragment was identified by target-specific degenerate primers and subsequently sequenced, revealing a giant nbr gene cluster harboring genes (nbrCDEF) required for TDP-2dF biosynthesis and those for PK-I biosynthesis, modification and regulation. The results showed that the genetic and domain arrangements of nbr PK-I synthases agreed colinearly with the PK-I structures of brasilinolides. Subsequent heterologous expression of nbrCDEF in Escherichia coli accomplished in vitro reconstitution of TDP-2dF biosynthesis. The catalytic functions and mechanisms of NbrCDEF enzymes were further characterized by systematic mix-and-match experiments. The enzymes were revealed to display remarkable substrate and partner promiscuity, leading to the establishment of in vitro hybrid deoxysugar biosynthetic pathways throughout an in situ one-pot (iSOP) method. This study represents the first demonstration of TDP-2dF biosynthesis at the enzyme and molecular levels, and provides new hope for expanding the structural diversity of brasilinolides by combinatorial biosynthesis.
Vision-Based Landing System Design for a Small UAV
(2015)
Lin, Yu-Fu
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Lu, Wei-Min
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Chen, Kuan-Hung
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Guo, Jiun-In
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電子工程學系及電子研究所
This paper presents a vision-based landing system concept which could be implemented in a small UAV (Unmanned Aerial Vehicle). Vision-based object detection provides object position information of objects such as pedestrian or road, and those detection methods can also provide precise position during the landing stage of aircraft. Besides, the take off weight of a small UAV should be light in order to increase endurance. Vision-based sensor is much low-cost compared with other sensors such as RADAR (Radio Detection And Ranging), LiDAR (Light Detection And Ranging) or DGPS (differential GPS) module. However, vision-based object detection methods have several challenges such as weather conditions, low illumination capability, and high false detection rate in complicated environment. Accordingly, this paper presents a practical method that can conquers the above challenges for vision-based landing system for UAV. In addition to desktop simulation, we also realize the proposed method on a portable device.
Vision-Based Moving Objects Detection for Intelligent Automobiles and a Robustness Enhancing Method
(2014-01-01)
Ju, Ting-Fung
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Lu, Wei-Min
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Chen, Kuan-Hung
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Guo, Jiun-In
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電子工程學系及電子研究所
This paper presents a vision-based moving objects detection work which attracts much attention in intelligent automobile applications recently. Vision-based objects detection provides object behavior information of objects and is an intuitive detection method similar to human visual perception. Besides, vision-based objects detection methods are much low-cost compared with detection methods such as RADAR (Radio Detection And Ranging), or LiDAR (Light Detection And Ranging). However, current vision-based objects detection methods still suffer from several challenges such as high false alarms and unstable detection rate which limit their value in practical applications. Accordingly, this paper presents a robustness enhancing method for vision-based moving objects detection.