Browsing by Author "Chen, I-Wei"

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A Wearable Photoplethysmographic System Realization with Efficient Motion Artifact Reduction Method Based on Recursive Least Squares Adaptive Filtering Algorithm
(2018-01-01)
Chen, I-Wei
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Wu, Chih-Chin
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Fang, Wai-Chi
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電子工程學系及電子研究所
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Department of Electronics Engineering and Institute of Electronics
The appearances of Motion Artifacts (MAs) in the photoplethysmographic (PPG) signals is one of the major obstacles to improve the accuracy and the stability of the signals analysis. In this paper, we present an effective and adaptive method based on DC Remover method and Recursive Least Squares (RLS) adaptive filter for reducing MAs disturbances from PPG signals. The results achieved by the presented methodology show a high correlation coefficient between Electrocardiography derived heart rate and PPG-derived heart rate (R=0.8054), moreover, the accuracy of heart rate monitoring was improved. The proposed system was implemented in hardware design for wearable and home-care applications.
An Efficient Hardware Architecture Design of EEMD Processor for Electrocardiography Signal
(2018-01-01)
Chen, I-Wei
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Chuang, Shang-Yi
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Wu, Wen-Jun
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Fang, Wai-Chi
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電子工程學系及電子研究所
This study proposed an efficient hardware architecture design of Ensemble Empirical Mode Decomposition (EEMD) processor for the signal analysis of Electrocardiography (ECG). The proposed processor is implemented in an on-board Xilinx FPGA for on-line signal processing of the non-linear and non-stationary signal. The EEMD method is appropriate to analyze the non-linear ECG signal with assisting white noise and decompose the signal into 8 sets of Intrinsic Mode Functions (IMFs). The experimental result shows that the mode mixing problem, which exists in the Empirical Mode Decomposition (EMD) method, solved by the proposed EEMD processor. The study solves the obstacle of mode mixing and achieves high accuracy with data error < 4.7x10(-5). This approach can effectively analyze the non-linear and non-stationary biomedical signal and facilitate cardiovascular diseases diagnosis and long-term monitoring.
An electronic silicon-based memristor with a high switching uniformity
(2019-02-01)
Lu, Yang
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Alvarez, Ana
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Kao, Chung-Ho
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Bow, Jong-Shing
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Chen, San-Yuan
Metal-insulator-metal devices known as memristors offer voltage-regulated nanoscale conductivity and are of interest in the development of non-volatile random access memory. Typically, however, their tunable conductivity is the result of migrating ions within a stochastically formed filament, and as such their combined resistor-memory performance suffers. Here we show that amorphous silicon compositions, which are doped with oxygen or nitrogen and sandwiched between metal electrodes, can be used to create purely electronic memristors. The devices have coherent electron wave functions that extend to the full device thickness (more than 15 nm) and, despite the thinness and very high aspect ratio of the devices, electrons still follow an isotropic, three-dimensional pathway, thus providing uniform conductivity at the nanoscale. Such pathways in amorphous insulators are derived from overlapping gap states and regulated by trapped charge, which is stabilized by electron-lattice interaction. As a result, the nanometallic memristors also exhibit pressure-triggered insulator-to-metal transitions. Our silicon-based memristors, which could be readily integrated into silicon technology, are purely electronic and offer switching capabilities that are fast, uniform, durable, multi-state and low power.
An Integrated. PPG and. ECG Signal Processing Hardware Architecture Design of EEMD Processor
(2019-01-01)
Fang, Wai-Chi
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Chen, I-Wei
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
This study proposed an integrated Photoplethysmogram (PPG) and Electrocardiography (ECG) simal processing hardware architecture design based on Ensemble Empirical Mode Decomposition (EEMD) The proposed integrated dual signals EEMD processor is implemented in an on-board FPGA for on-line signal processing of the non-linear and non-stationary signal. The EEMD method is appropriate to analyze the non-linear PPG and ECG signals with assisting white noise and decompose the signal into 8 sets of Intrinsic Mode Functions (MI's). The experimental results show that the hardware architecture proposed in this study can be applied to PPG and ECG signals, and can clearly analyze and separate high-frequency and low frequency noise, and keep clear signals without any noise.
Biomedical nanoparticle carriers with combined thermal and magnetic responses
(2009-02-01)
Liu, Ting-Yu
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Hu, Shang-Hsiu
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Liu, Dean-Mo
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Chen, San-Yuan
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Chen, I-Wei
Several biocompatible polymers are capable of large responses to small temperature changes around 37 degrees C In water, their responses include shrinkage and swelling as well as transitions in wettability. These properties have been harnessed for biomedical applications such as tissue engineering scaffolds and drug delivery carriers. A soft material/hard material hybrid in which a magnetic: metal or oxide is embedded in a temperature-responsive polymer matrix can combine the thermal sensitivity with magnetic signatures. Importantly, nanosizing such construct brings about new desirable features of extremely fast thermal response time, small magnetic hysteresis and enhanced magnetic susceptibility. Remote magnetic maneuvering and heating of the hybrid nanocolloids makes possible such applications as high-throughput enzyme separation and cell screening. Robust drug release on demand may also be obtained using these colloids and nanoparticle-derived thin film devices of combined thermal magnetic sensitivity. (C) 2008 Elsevier Ltd. All rights reserved.
Biomimetic nano-surfactant stabilizes sub-50 nanometer phospholipid particles enabling high paclitaxel payload and deep tumor penetration
(2018-10-01)
Choi, Hoon
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Liu, Ting
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Qiao, Hui
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Chacko, Ann-Marie
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Hu, Shang-Hsiu
Sub-50 nm nanoparticles feature long circulation and deep tumor penetration. However, at high volume fractions needed for intravenous injection, safe, highly biocompatible phospholipids cannot form such nanoparticles due to the fluidity of phospholipid shells. Here we overcome this challenge using a nano-surfactant, a sterilized 18-amino-acid biomimetic of the amphipathic helical motif abundant in HDL-apolipoproteins. As it induces a nanoscale phase (glass) transition in the phospholipid monolayer, the peptide stabilizes 5-7 nm phospholipid micelles that do not fuse at high concentrations but aggregate into stable micellesomes exhibiting size-dependent penetration into tumors. In mice bearing human Her-2-positive breast cancer xenografts, high-payload paclitaxel encapsulated in 25 nm (diameter) micellesomes kills more cancer cells than paclitaxel in standard clinical formulation, as evidenced by the enhanced apparent diffusion coefficient of water determined by in vivo MR imaging. Importantly, the bio-inertness of this biomimetic nano-surfactant spares the nanoparticles from being absorbed by liver hepatocytes, making them more generally available for drug delivery. (C) 2018 Elsevier Ltd. All rights reserved.
Core-Shell Nanocapsules Stabilized by Single-Component Polymer and Nanoparticles for Magneto-Chemotherapy/Hyperthermia with Multiple Drugs
(1970-01-01)
Hu, Shang-Hsiu
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Liao, Bang-Jie
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Chiang, Chin-Sheng
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Chen, Po-Jung
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Chen, I-Wei
Extracting Attack Sessions from Real Traffic with Intrusion Prevention Systems
(2009)
Chen, I-Wei
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Lin, Po-Ching
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Luo, Chi-Chung
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Cheng, Tsung-Huan
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Lin, Ying-Dar
False Positive (FP) and False Negative (FN) happen to every Intrusion Prevention System (IPS). No one could do better judgment than others all the time. This work proposes a system of Attack Session Extraction (ASE) to create a pool of suspicious traffic traces which cause potential FNs (abbreviated as P-FNs) and potential FPs (abbreviated as P-FPs) to IPSes. Developers of IPSes can use these suspicious traffic traces to improve the accuracy of their products. Traffic traces are called suspicious since what they cause are P-FNs and P-FPs which need to be confirmed by the developers of IPSes whether P-FNs are FNs and P-FPs are FPs. First, the ASE captures real traffic and replays captured traffic traces to multiple IPSes. By comparing the logs of IPSes, we can find that some attack logs are logged or not logged only at certain IPS. The former is P-FPs, while the latter is P-FNs to that IPS. The ASE then starts to extract this suspicious traffic from replayed traffic traces. The extracted traffic traces can then be used for further analysis by IPS developers. Some of the traces may prove to be guilty, i.e. confirmed to be FNs and FPs. To completely extract a suspicious session, the ASE uses an association mechanism based on anchor packets, five-tuple and time, and similarity for the first packet, first connection, and whole session, respectively. It calculates the degree of similarity among packets to extract a suspicious session containing multiple connections. We define variation and completeness/purity as the performance indexes to evaluate ASE. The experiments demonstrate that 95% of extracted sessions have low variation, and the average completeness/purity is around 80%.
Low-Storage Capture and Loss Recovery Selective Replay of Real Flows
(2012-04-01)
Lin, Ying-Dar
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Lin, Po-Ching
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Cheng, Tsung-Huan
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Chen, I-Wei
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Lai, Yuan-Cheng
Capturing and replaying real flows are important for testing network security products. However, capturing real flows demands a high storage cost and runs a risk of capture loss, which makes the replay inaccurate. Replaying real flows should be accurate and stateful to adapt to the reaction of the device under test. It should also efficiently reproduce a defect and help developers identify the flows triggering defects. Therefore, this work first presents the (N, M, P) capture scheme which begins with, for each connection, capturing at most N bytes of application payload and then at most M bytes of application payload for at most each of the subsequent P packets in the same connection. This scheme reduces 87 percent of storage cost while retaining 99.74 percent of original events. This work develops a tool named SocketReplay with the mechanisms of loss recovery, stateful replay, and selective replay. Loss recovery tracks TCP sequence numbers to identify capture loss and recovers incomplete flows with dummy data. Stateful replay maintains the states in the TCP/IP stack to replay real flows. Selective replay incrementally selects flows to replay. The results show that SocketReplay can accurately and efficiently reproduce product events and significantly decrease the volume of replayed packet traces.
NIR-Triggered Synergic Photo-chemothermal Therapy Delivered by Reduced Graphene Oxide/Carbon/Mesoporous Silica Nanocookies
(2014-01-01)
Chen, Yu-Wei
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Chen, Po-Jung
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Hu, Shang-Hsiu
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Chen, I-Wei
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Chen, San-Yuan
On Campus Beta Site: Architecture Designs, Operational Experience, and Top Product Defects
(2010-12-01)
Lin, Ying-Dar
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Chen, I-Wei
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Lin, Po-Ching
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Chen, Chang-Sheng
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Hsu, Chun-Hung
Testing network products in a beta site to reduce the possibility of customer found defects is a critical phase before marketing. We design and deploy an innovative beta site on the campus of National Chiao Tung University, Hsinchu, Taiwan. It can be used for developers to test and debug products, while maintaining network quality for network users. To satisfy the needs of developers, we set up environments and mechanisms, such as a variety of test zones for multiple types of products or systems under test (SUTs), remote control, degrees of traffic volume, and traffic profiling. For network users, we set up mechanisms of failure detection, notification, and recovery. The beta site network users are all volunteers. Test results show that beta site testing is good for finding stability and compatibility defects. The period starting from the beginning of a test until the next defect is found is called the time to fail (TTF). We call it converged if the TTF exceeds four weeks, and the convergence ratio is the percentage of SUTs that reach convergence. We find that the TTF increases with longer test duration, meaning that product quality improves through beta site testing. However, the convergence ratios are only 7 and 20 percent for test durations of one month and one year, respectively, meaning that few products operate faultlessly for a long duration. The convergence ratios also indicate that it takes much more time to enhance product quality to be converged. Therefore, if considering both marketing timing and product quality, one month is our suggested minimum TD for low-end and short-life-cycle products. However, we recommend one year as the minimum TD for high-end and long-life-cycle products.
PCAPLib: A System of Extracting, Classifying, and Anonymizing Real Packet Traces
(2016-06)
Lin, Ying-Dar
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Lin, Po-Ching
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Wang, Sheng-Hao
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Chen, I-Wei
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Lai, Yuan-Cheng
This paper presents the PCAPLib system for providing extracted, well-classified, and anonymized packet traces from real network traffic with two mechanisms. First, active trace collection actively extracts and classifies packet traces into sessions by leveraging multiple detection devices. Second, deep packet anonymization protects the privacy in the packet payloads for hundreds of application protocols while preserving the utility of the traces. We evaluate 318 anonymized packet traces collected over a period of four months and show that the efficiency of anonymization is up to 96%. The usefulness of this system for assessing false positives/false negatives in intrusion detection has been also demonstrated.
Photoresponsive Protein-Graphene-Protein Hybrid Capsules with Dual Targeted Heat-Triggered Drug Delivery Approach for Enhanced Tumor Therapy
(2014-07-01)
Hu, Shang-Hsiu
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Fang, Ren-Hong
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Chen, Yu-Wei
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Liao, Bang-Jie
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Chen, I-Wei
A novel photo-responsive protein-graphene-protein (PGP) capsule that doubles as a photothermal agent with core/shell structure is constructed by anchoring reduced graphene oxide nanosheets on one-component protein (lactoferrin) shell through a double emulsion method. PGP capsules can transport fully concealed hydrophilic anticancer cargo, doxorubicin (Dox), with a large payload (9.43 mu mol g(-1)) to be later unloaded in a burst-like manner by photo-actuation triggered by near-infrared irradiation. Being bio-compatible yet with a high cancer cell targeting efficiency, PGP capsules have successfully eradicated subcutaneous tumors in 10 d following a single 5 min NIR irradiation without distal damage. Besides, the photochemothermal therapy of PGP capsules eradicates tumor cells not only in the light-treating area but also widely light-omitted tumor cells, overcoming the tumor recurrence due to efficient cell killing efficacy. These results demonstrate that the PGP capsule is a potential new drug delivery platform for local-targeting, on-demand, photoresponsive, combined chemotherapy/hyperthermia for tumor treatment and other biomedical applications.
Photoresponsive Protein-Graphene-Protein Hybrid Capsules with Dual Targeted Heat-Triggered Drug Delivery Approach for Enhanced Tumor Therapy
(2014-07-01)
Hu, Shang-Hsiu
;
Fang, Ren-Hong
;
Chen, Yu-Wei
;
Liao, Bang-Jie
;
Chen, I-Wei
A novel photo-responsive protein-graphene-protein (PGP) capsule that doubles as a photothermal agent with core/shell structure is constructed by anchoring reduced graphene oxide nanosheets on one-component protein (lactoferrin) shell through a double emulsion method. PGP capsules can transport fully concealed hydrophilic anticancer cargo, doxorubicin (Dox), with a large payload (9.43 mu mol g(-1)) to be later unloaded in a burst-like manner by photo-actuation triggered by near-infrared irradiation. Being bio-compatible yet with a high cancer cell targeting efficiency, PGP capsules have successfully eradicated subcutaneous tumors in 10 d following a single 5 min NIR irradiation without distal damage. Besides, the photochemothermal therapy of PGP capsules eradicates tumor cells not only in the light-treating area but also widely light-omitted tumor cells, overcoming the tumor recurrence due to efficient cell killing efficacy. These results demonstrate that the PGP capsule is a potential new drug delivery platform for local-targeting, on-demand, photoresponsive, combined chemotherapy/hyperthermia for tumor treatment and other biomedical applications.
Quantum-Dot-Tagged Reduced Graphene Oxide Nanocomposites for Bright Fluorescence Bioimaging and Photothermal Therapy Monitored In Situ
(2012-04-03)
Hu, Shang-Hsiu
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Chen, Yu-Wei
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Hung, Wen-Ting
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Chen, I-Wei
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Chen, San-Yuan
Quantum-dot-tagged reduced graphene oxide (QD-rGO) nanocomposites (left) internalized into targeted tumor cells display bright fluorescence from the QDs (right); by absorbing NIR radiation incident on the rGO and converting it into heat, they also cause simultaneous cell death and fluorescence reduction (bottom). The nanocomposite is thus capable of tumor imaging, photothermal therapy and in situ monitoring of treatment in progress.
Statistical Analysis of False Positives and False Negatives from Real Traffic with Intrusion Detection/Prevention Systems
(2012-03-01)
Ho, Cheng-Yuan
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Lai, Yuan-Cheng
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Chen, I-Wei
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Wang, Fu-Yu
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Tai, Wei-Hsuan
False positives and false negatives happen to every intrusion detection and intrusion prevention system. This work proposes a mechanism for false positive/negative assessment with multiple IDSs/IPSs to collect FP and FN cases from real-world traffic and statistically analyze these cases. Over a period of 16 months, more than 2000 FPs and FNs have been collected and analyzed. From the statistical analysis results, we obtain three interesting findings. First, more than 92.85 percent of false cases are FPs even if the numbers of attack types for FP and FN are similar. That is mainly because the behavior of applications or the format of the application content is self-defined; that is, there is not complete conformance to the specifications of RFCs. Accordingly, when this application meets an IDS/IPS with strict detection rules, its traffic will be regarded as malicious traffic, resulting in a lot of FPs. Second, about 91 percent of FP alerts, equal to about 85 percent of false cases, are not related to security issues, but to management policy. For example, some companies and campuses limit or forbid their employees and students from using peer-to-peer applications; therefore, in order to easily detect P2P traffic, an IDS/IPS is configured to be sensitive to it. Hence, this causes alerts to be triggered easily regardless of whether the P2P application has malicious traffic or not. The last finding shows that buffer overflow, SQL server attacks, and worm slammer attacks account for 93 percent of FNs, even though they are aged attacks. This indicates that these attacks always have new variations to evade IDS/IPS detection.
Temperature-Sensitive Nanocapsules for Controlled Drug Release Caused by Magnetically Triggered Structural Disruption
(2009-02-24)
Liu, Ting-Yu
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Liu, Kun-Ho
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Liu, Dean-Mo
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Chen, San-Yuan
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Chen, I-Wei
Self-assembled nanocapsules containing a hydrophilic core and a crosslinked yet thermosensitive shell are successfully prepared using poly(ethylene-oxide) poly(propylene-oxide)-poly(ethylene-oxide) block copolymers, 4-nitrophenyl chloroformate, gelatin, and 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide. The core is further rendered magnetic by incorporating iron oxide nanoparticles via internal precipitation to enable externally controlled actuation under magnetic induction. The spherical nanocapsules exhibit a hydrophilic-to-hydrophobic transition at a characteristic but tunable temperature reaching 40 degrees C, triggering a size contraction and shrinkage of the core. The core content experiences very little leakage at 25 degrees C, has a half life about 5 h at 45 degrees C, but bursts out within a few minutes under magnetic heating due to iron oxide coarsening and core/shell disruption. Such burst-like response may be utilized for controlled drug release as illustrated here using a model drug Vitamin B12.