Browsing by Author "Lin, Yu-Chiun"

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A predictive location tracking algorithm for mobile devices with deficient signal sources
(2007)
Lin, Yu-Chiun
;
Tseng, Po-Hsuan
;
Feng, Kai-Ten
;
電信工程研究所
;
Institute of Communications Engineering
Location estimation and tracking for the mobile devices have attracted a significant amount of attention in recent years. The network-based location estimation schemes have been widely adopted based on the radio signals between the mobile device and the base stations. The location estimators associated with the Kalman filtering techniques are exploited to both acquire location estimation and trajectory tracking for the mobile devices. However, most of the existing schemes become unapplicable due to the insufficiency of signal sources. In this paper, a Predictive Location Tracking (PLT) algorithm is proposed to alleviate this problem. The predictive information obtained from the Kalman filter is employed to provide the additional signal inputs for the location estimators. The proposed PLT scheme can offer persistent accuracy for location tracking of the mobile devices, especially with inadequate signal sources. Numerical results demonstrate that the proposed PLT algorithm can achieve better precision, comparing with other existing schemes, in mobile location estimation and tracking.
Chaotic Phase Space Differential (CPSD) Algorithm for Real-Time Detection of VF, VT, and PVC ECG Signals
(2009)
Liu, Chien-Sheng
;
Lin, Yu-Chiun
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Chuang, Yueh-Hsun
;
Hsiao, Tze-Chien
;
Lin, Chii-Wann
The continuous evolution of electrocardiography (ECG) recording has enabled the successful development of many significant applications of this vital signal for clinical diagnosis and monitoring. Recent trends in device miniaturization and wireless transmission have extended the uses of such a signal modality to telemedicine for home cares. However, it has posted new technical challenges for the scenarios of home users and associated business models. Among them, a smart algorithm for real time or early indication of critical cardiac conditions, e.g. ventricular fibrillation (VF), Ventricular Tachycardia (VT), are extremely important for sharing the work loads of remote side for proper responses and delivery of health care. It would be also rather critical to fit such a computation task into the wearable or mobile device for the requirement of low power consumption. In this paper, we report the development of a novel analysis algorithm based on Time-Delayed Phase Space Reconstruction (PSR) method to differentiate abnormal ECG segments from entire records. We used BIH-MIT arrhythmia database and CU database to verify our original ideas. According to our test results, this algorithm successfully identified the three heart diseases of PVC (Premature Ventricular Contraction), VF (Ventricular Fibrillation) and VT (Ventricular Tachycardia) immediately. We calculated the statistic parameters to estimate the efficiency: the average of sensitivity is 98.7% and the specificity reaches 96.2%. We also implemented this algorithm for wearable applications in a single-chip micro controller (MSP430, TI) for arrhythmia ECG data. The total code size is about a few hundred bytes and the execute time meets the order of sub-second. This new algorithm provides a powerful real-time index for clinical diagnosis and long-term home-care applications.
Experimental and Theoretical Study of Low-Cost Hydrothermally Grown Nanowire Silicon Solar Cell
(2013)
Li, Hung-Hsien
;
Lin, Albert S.
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Zhong, Yan-Kai
;
Fu, Sze-Ming
;
Lai, Shih-Yun
The low cost and high absorbance is the two most important considerations for thin-film silicon photovoltaics. In this work, aluminum doped zinc oxide(AZO) nanowire is grown by low cost hydrothermal method and nano-structured amorphous silicon(alpha-Si) solar cell is realized on these AZO nanowire substrate. The experimental result shows superior light trapping property compared to conventional planar structure with 18.83% improvement in photocurrent. Simulation result shows the required thickness for full absorption for high aspect ratio AZO nanowire solar cell is similar to 0.3 square m, much thinner than planar type solar cell. The calculation reveals that solar cell absorbance increases with the nanowire length and packing density, indicating material volume is the first order effect for nanowire solar cells. The proposed low-cost AZO nanowire array amorphous silicon solar cell is very promising for future nanostructured silicon photovoltaics.
Wireless Location Tracking Algorithms for Environments with Insufficient Signal Sources
(2009-12-01)
Tseng, Po-Hsuan
;
Feng, Kai-Ten
;
Lin, Yu-Chiun
;
Chen, Chao-Lin
;
電信工程研究所
Location estimation and tracking for the mobile devices have attracted a significant amount of attention in recent years. The network-based location estimation schemes have been widely adopted based on the radio signals between the mobile device and the base stations. The location estimators associated with the Kalman filtering techniques are exploited to both acquire location estimation and trajectory tracking for the mobile devices. However, most of the existing schemes become inapplicable for location tracking due to the deficiency of signal sources. In this paper, two predictive location tracking algorithms are proposed to alleviate this problem. The Predictive Location Tracking (PLT) scheme utilizes the predictive information obtained from the Kalman filter in order to provide the additional signal inputs for the location estimator. Furthermore, the Geometric-assisted PLT (GPLT) scheme incorporates the Geometric Dilution of Precision (GDOP) information into the algorithm design. Persistent accuracy for location tracking can be achieved by adopting the proposed GPLT scheme, especially with inadequate signal sources. Numerical results demonstrate that the GPLT algorithm can achieve better precision in comparison with other network-based location tracking schemes.