Browsing by Author "Chen, Tzu-Yu"

Now showing 1 - 12 of 12

135-MHz 258-K Gates VLSI Design for All-Intra H.264/AVC Scalable Video Encoder
(2013-04-01)
Li, Gwo-Long
;
Chen, Tzu-Yu
;
Shen, Meng-Wei
;
Wen, Meng-Hsun
;
Chang, Tian-Sheuan
To satisfy the video application diversities, an extension of H.264/advanced video coding (AVC), called scalable video coding (SVC), is designed to provide multiple demanded video data via a single video encoder. However, constructed on the fundamental of H.264/AVC, the complexity of SVC is much higher than that of H.264/AVC. In this paper, a VLSI design for all-intra scalable video encoder is proposed to aim at efficient scalable video encoding. First, the memory bandwidth requirements for several encoding methods are analyzed to find out the best encoding method which can achieve best tradeoff between internal memory usage and external memory access. Afterward, an all-intra SVC encoder combined with several advanced techniques, including fast intra prediction algorithm, efficient syntax element encoding approach in context-adaptive variable-length coding, and hardware-efficient techniques, are implemented in a macroblock (MB)-level pipeline to increase data throughput. Implementation results demonstrate that our proposed SVC encoder can process more than 594-k MBs per second, which is equivalent to the summation of 60 high-definition, 1080-p, SD 480-p, and common intermediate format frames under 135-MHz working frequency. The proposed design consumes 258-K gate counts when synthesized by 90-nm CMOS technology.
All Inorganic Perovskite Quantum Dots Hybrid Green Light-Emitting Diode with Stable Performance
(2018-01-01)
Yu, Chung-Ping
;
Chung, Meng-Ting
;
Chen, Tzu-Yu
;
Huang, Yu-Ming
;
Huang, Chung-Ping
A silica-coated inorganic perovskite quantum dot hybrid light-emitting diodes is aged continuously in high and low light intensity conditions. Both blue and ultra-violet-pumped samples showed stable performances up to 104 hours.
AUTOENCODING HRTFS FOR DNN BASED HRTF PERSONALIZATION USING ANTHROPOMETRIC FEATURES
(2019-01-01)
Chen, Tzu-Yu
;
Kuo, Tzu-Hsuan
;
Chi, Tai-Shih
;
電機工程學系
;
Department of Electrical and Computer Engineering
We proposed a deep neural network (DNN) based approach to synthesize the magnitude of personalized head-related transfer functions (HRTFs) using anthropometric features of the user. To mitigate the over-fitting problem when training dataset is not very large, we built an autoencoder for dimensional reduction and establishing a crucial feature set to represent the raw HRTFs. Then we combined the decoder part of the autoencoder with a smaller DNN to synthesize the magnitude HRTFs. In this way, the complexity of the neural networks was greatly reduced to prevent unstable results with large variance due to overfitting. The proposed approach was compared with a baseline DNN model with no autoencoder. The log-spectral distortion (LSD) metric was used to evaluate the performance. Experiment results show that the proposed approach can reduce LSD of estimated HRTFs with greater stability.
CdSe/ZnS core-shell quantum dot assisted color conversion of violet laser diode for white lighting communication
(2019-12-01)
Wang, Wei-Chun
;
Wang, Huai-Yung
;
Chen, Tzu-Yu
;
Tsai, Cheng-Ting
;
Cheng, Chih-Hsien
By color-converting the violet laser diode (VLD) with a cadmium selenide and zinc sulfide (CdSe/ZnS) core-shell-quantum dot (QD) doped polydimethylsiloxane (PDMS) film, the VLD+CdSe/ZnS core-shell-QD transferred white-light with improved color rendering index (CRI) is demonstrated for high-speed indoor visible lighting communication. To facilitate hue saturation value (HSV) of the VLD +CdSe/ZnS core-shell-QD white-lighting module, dual-sized CdSe/ZnS core-shell-QDs with two luminescent wavelengths centered at 515 and 630 nm are doped into the PDMS. The CdSe/ZnS core-shell-QD doped PDMS phosphor with the optimized thickness of 2.5 mm serves as the beam divergent color-converter, which not only excites red (R) and green (G) fluorescence to detune the correlated color temperature (CCT) and CRI of the mixed red/green/violet (RGV) white-light, but also remains the residual VLD signal for data transmission. With a divergent angle of 127 degrees, such a VLD + CdSe/ZnS core-shell-QD can deliver cold white-light with a CCT of 6389 K and a CRI of 63.3 at Commission International de l'Eclairage coordinate of 0.3214, 0.2755. Most important, the residual VLD light component is relatively weak with its wavelength out of the peak optical sensitivity region of the human retina centered at 441 nm. The directly encoded VLD+CdSe/ZnS core-shell-QD white light successfully carries the 16-quadrature amplitude modulation (QAM) discrete multitone data, which supports the maximal transmission data rate of 9.6 Gbit/s with a bit error ratio (BER) of 3.59 x 10(-3).
Exploring redundancy of HRTFs for fast training DNN-based HRTF personalization
(2018-01-01)
Chen, Tzu-Yu
;
Hsiao, Po-Wen
;
Chi, Tai-Shih
;
電機工程學系
;
Department of Electrical and Computer Engineering
A deep neural network (DNN) is constructed to predict the magnitude responses of the head-related transfer functions (HRTFs) of users for a specific direction and a specific ear. Using the CIPIC HRTF database (including 25 azimuth angles and 50 elevation angles for both ears), we trained 2500 DNNs to predict magnitude responses of all HRTFs of a user. To reduce training time, we propose to use the final weights of the trained DNN of a nearby direction as the initial weights of the current DNN under training since magnitude responses of the HRTFs are smoothly changing across nearby directions. Analysis of variance (ANOVA) was performed to show that the proposed training scheme produces equivalent magnitude responses of HRTFs as the standard training scheme with random initial weights in terms of the log-spectral distortion (LSD) measure. Meanwhile, the proposed training scheme can dramatically reduce training time by more than 95%.
HIT Solar Cell Performance Enhancement with Luminescent Down Shifting Phenomenon
(2018-01-01)
Lin, Albert
;
Huang, Chien-Yao
;
Parashar, Parag
;
Chou, Hao-Ming
;
Lin, Yi-Shiuan
Luminescent down-shifting (LDS) phenomenon has been employed to enhance the HIT solar cell efficiency. The efficiency and J(SC) are increased by 2.3% and 11.5% respectively. External quantum efficiency (EQE) data supports our claim.
Hybrid-type white LEDs based on inorganic halide perovskite QDs: candidates for wide color gamut display backlights
(2019-05-01)
Lin, Chih-Hao
;
Verma, Akta
;
Kang, Chieh-Yu
;
Pai, Yung-Min
;
Chen, Tzu-Yu
We demonstrate inorganic halide perovskite quantum-dots-based white light-emitting diodes via three different geometries, including liquid, solid, and hybrid types. Problems of fast anion exchange and aggregation in the cases of liquid- and solid-type devices are discussed in detail and push us to move towards the fabrication of a hybrid-type device structure. The experiment results illustrate that a hybrid-type device has the highest luminance efficiency (51 lm/W) and a wide color gamut (122% of NTSC and 91% of Rec. 2020). Therefore, we conclude that a hybrid-type device can provide an outstanding color gamut for high color gamut display applications. (c) 2019 Chinese Laser Press
In Situ Activation of Pituitary-Infiltrating T Lymphocytes in Autoimmune Hypophysitis
(2017-03-06)
Lin, Han-Huei
;
Gutenberg, Angelika
;
Chen, Tzu-Yu
;
Tsai, Nu-Man
;
Lee, Chia-Jung
Autoimmune hypophysitis (AH) is a chronic inflammatory disease characterized by infiltration of T and B lymphocytes in the pituitary gland. The mechanisms through which infiltrating lymphocytes cause disease remain unknown. Using a mouse model of AH we assessed whether T lymphocytes undergo activation in the pituitary gland. Infiltrating T cells co-localized with dendritic cells in the pituitary and produced increased levels of interferon-gamma and interleukin-17 upon stimulation in vitro. Assessing proliferation of CD3- and B220-postive lymphocytes by double immunohistochemistry (PCNA-staining) and flow cytometry (BrdU incorporation) revealed that a discrete proportion of infiltrating T cells and B cells underwent proliferation within the pituitary parenchyma. This proliferation persisted into the late disease stage (day 56 post-immunization), indicating the presence of a continuous generation of autoreactive T and B cells within the pituitary gland. T cell proliferation in the pituitary was confirmed in patients affected by autoimmune hypophysitis. In conclusion, we show that pituitary-infiltrating lymphocytes proliferate in situ during AH, providing a previously unknown pathogenic mechanism and new avenues for treatment.
Memory Analysis for H.264/AVC Scalable Extension Encoder
(2009)
Chen, Tzu-Yu
;
Li, Gwo-Long
;
Chang, Tian-Sheuan
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
In this paper, the first overall memory analysis for H.264/AVC scalable extension (SVC) is presented. Since the dependency among layers is a major discrepancy between SVC and H.264/AVC, the hardware design about them is quite different. Therefore, we analyze the memory bandwidth and memory access requirement of different coding flows for SVC. Based on the analysis results, we deduce that the frame-level method enjoys the best performance. With some improvements from previous work and proposal by our observation, the external memory access could be further reduced by at least 53% than initial design. Furthermore, through our analysis, a solution is provided for the trade-off between internal memory storage and external memory bandwidth in hardware design.
Optimization of nano-honeycomb structures for flexible w-LEDs
(2017-08-21)
Lin, Huang-Yu
;
Pai, Yung-Min
;
Shi, Jing-xing
;
Chen, Xin-Yin
;
Lin, Chung-Hsiang
This study presents the low cost fabrication of flexible white-light-emitting diodes (w-LEDs) with nano-honeycomb-structured phosphor films. Extending the dimensions of the nano-honeycomb structures improved the color uniformity of the flexible samples, and the 950-nm pattern sample demonstrated optimal color uniformity because this nano-pattern exhibited an excellent diffusion ability owing to its pitch size. In addition to color uniformity, the use of this nano-pattern improved the luminous efficiency. The 750-nm pattern exhibited the highest luminous efficiency (235.8 lm/W), which was approximately 7% higher than that exhibited by a non-patterned phosphor film sample. Thus, flexible w-LEDs with nano-honeycomb structure optimization have great potential to be used as next-generation lighting sources. (C) 2017 Optical Society of America
Photoluminescence-Driven Broadband Transmitting Directional Optical Nanoantennas
(2018-09-01)
See, Kel-Meng
;
Lin, Fan-Cheng
;
Chen, Tzu-Yu
;
Huang, You-Xin
;
Huang, Chen-Hsien
Optical nanoantennas mediate near and far optical fields. Operating a directional nanoantenna in transmitting mode is challenging because the antenna needs to be driven by a nanosized optical frequency generator, which must work at the antenna's resonance frequency and be precisely attached to the antenna's feed with correct polarization. Quantum emitters have been used as optical nanogenerators, but their precise positioning relative to the nanoantenna is technically challenging, setting up a barrier to the practical implementation. One unique source to drive nanoantenna is the photoluminescence from the material of the nanoantenna because the high operational frequency of the antenna reaches the regime for the electronic transitions in matter. Here, we exploit plasmon-modulated photoluminescence (PMPL) as an effective optical source to drive directional nanoantennas. We experimentally realize two technically challenging theoretical proposals, namely, an optical nanospectrometer based on Yagi-Uda nanoantennas and tunable broadband directional emission from log-periodic nanoantennas. Using photoluminescence from the nanoantenna as an optical source promotes practical implementation of transmitting optical nanoantennas.
Ultrawide Color Gamut Perovskite and CdSe/ZnS Quantum-Dots-Based White Light-Emitting Diode with High Luminous Efficiency
(2019-09-01)
Lin, Chih-Hao
;
Kang, Chieh-Yu
;
Verma, Akta
;
Wu, Tingzhu
;
Pai, Yung-Min
We demonstrate excellent color quality of liquid-type white light-emitting diodes (WLEDs) using a combination of green light-emitting CsPbBr3 and red light-emitting CdSe/ZnS quantum dots (QDs). Previously, we reported red (CsPbBr1.2I1.8) and green (CsPbBr3) perovskite QDs (PQDs)-based WLEDs with high color gamut, which manifested fast anion exchange and stability issues. Herein, the replacement of red PQDs with CdSe/ZnS QDs has resolved the aforementioned problems effectively and improved both stability and efficiency. Further, the proposed liquid-type device possesses outstanding color gamut performance (132% of National Television System Committee and 99% of Rec. 2020). It also shows a high efficiency of 66 lm/W and an excellent long-term operation stability for over 1000 h.