Browsing by Author "Chang, Shu-Hao"

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A Novel Multivariate Analysis Method with Noise Reduction
(2009)
Chang, Shu-Hao
;
Chiou, Yu-Jen
;
Yu, Chun
;
Lin, Chii-Wann
;
Hsiao, Tzu-Chien
In this paper, we develop a novel Partial Regularized Least Squares (PRLS) method which combined regularization algorithm with Partial Least Squares (PLS) analysis for noise reduction application. In general, Least Squares and PLS fall into an overfitting problem with ill-posed condition. It means that some feature selections make the training data to have better adaptability to the model, but the quality of prediction would be poorly compared to the training data for the testing information. We usually expected that the selected model should have consistent predicted result between the training data and testing data. In order to evaluate the performance of PRLS method, we generate two simulation data, i.e. cosine waveform and 8th polynomial waveform with Gaussian distribution noisy for calculating two values, i.e. Correlation Coefficient value (RR value) and Root Mean Square Error (RMSE) for testing. The results show that the RR value of PRLS is higher than PLS's at increasing noise-to-signal ratio. As well the RMSE of PRLS is lower than PLS's at same S/N ratio. We also show that the PRLS approximates to the desired output at calibration. It can be applied in real-world noise reduction in the future.
Upconversion effects on the performance of near-infrared laser-driven polymer photovoltaic devices
(2012-10-01)
Wu, Jyh-Lih
;
Chen, Fang-Chung
;
Chang, Shu-Hao
;
Tan, Kim-Shih
;
Tuan, Hsing-Yu
We have explored the upconversion (UC) effects resulting from the presence of NaYF4:Yb/Er nanocrystals in near-infrared laser-driven organic photovoltaic devices (OPVs). Illumination of these UC nanomaterials with monochromatic light (980 nm) led to emission of visible light, which was subsequently absorbed by the polymer photoactive layer. We infer that both the long-wavelength charge-transfer absorption of the polymer blend and the UC effect contributed to the obvious near-infrared photovoltaic response. The resulting UC effects led to noticeable enhancements in the photocurrent and the efficiencies of the OPV devices under illumination at 980 nm. (c) 2012 Elsevier B.V. All rights reserved.