Browsing by Author "Lee, Wei-Chin"

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Coherent acoustic phonon oscillation accompanied with backward acoustic pulse below exciton resonance in a ZnO epifilm on oxide-buffered Si(111)
(2016-08-17)
Lin, Ja-Hon
;
Shen, Yu-Kai
;
Liu, Wei-Rein
;
Lu, Chia-Hui
;
Chen, Yao-Hui
Unlike coherent acoustic phonons (CAPs) generated from heat induced thermal stress by the coated Au film, we demonstrated the oscillation from c-ZnO epitaxial film on oxide buffered Si through a degenerate pump-probe technique. As the excited photon energy was set below the exciton resonance, the electronic stress that resulted from defect resonance was used to induce acoustic wave. The damped oscillation revealed a superposition of a high frequency and long decay CAP signal with a backward propagating acoustic pulse which was generated by the absorption of the penetrated pump beam at the Si surface and selected by the ZnO layer as the acoustic resonator.
Design of A Memory-Based VLC Decoder for Portable Video Applications
(2008)
Lee, Wei-Chin
;
Li, Yao
;
Lee, Chen-Yi
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電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
In this paper, a VLC decoder supporting to decode coefficient data in blocks of MPEG-2 and CAVLC in H.264 is presented. To achieve programmability of the VLC decoder, a memory-based architecture with improved memory efficiency is proposed. Group-based look-up table (LUT) algorithm is extended to multi-table merging (MTM) which extracts redundancy of groups further. With multi-table merging algorithm, all coding tables are integrated into memory more efficiently. While the memory access may lead to much power consumption, a low-power scheme is proposed to reduce memory access. The distributed cache is adopted to save power and improve the decoding throughput as well. Simulation results show that the cache with replacement method can reduce about 60% similar to 95% memory accesses.