Browsing by Author "Lin, LC"

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Comment on "Triplet-to-singlet exciton formation in poly(p-phenylene-vinylene) light-emitting diodes" - Reply
(2004-02-06)
Lin, LC
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Meng, HF
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Shy, JT
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Horng, SF
;
Yu, LS
Comment on "Triplet-to-singlet exciton formation in poly(p-phenylene-vinylene) light-emitting diodes" - Reply
(2003-11-21)
Lin, LC
;
Meng, HF
;
Shy, JT
;
Horng, SF
;
Yu, LS
Hierarchical instruction encoding for VLIW digital signal processors
(2005)
Liu, CH
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Lin, TJ
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Chao, CM
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Hsiao, PC
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Lin, LC
VLIW-based architectures are very popular in high-performance DSP processors, for their relatively simpler implementations and more predictable execution times. But they need more program memory because of (1) the fixed-length instruction encoding, (2) NOP insertion due to limited parallelism, and (3) repetitive codes for loop unrolling. This paper describes a novel hierarchical instruction encoding that address these three problems to improve the VLIW code density. In our simulations, the proposed encoding scheme saves 61.4%-66.9% code sizes in highly parallel DSP kernels, and more savings can be expected for general programs. Besides, a simple decoding architecture is proposed and has been integrated into a 4-way VLIW DSP processor. The prototype is implemented in the 0.18um CMOS technology with its operating frequency at 208MHz.
Novel programmable digital signal processor for multimedia applications
(2004)
Lin, LC
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Lin, TJ
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Lee, CC
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Chao, CM
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Chen, SK
This paper presents a novel DSP architecture for multimedia applications. The DSP core is a simple RISC processor from the programmer's view, which has a high-performance DSP unit and the applications can be easily targeted on the RISC shell to reduce the development time. Moreover, the DSP unit is itself a fully-programmable 4-way VLIW datapath, which has a novel ping-pong register file. To smooth the instruction execution of the two-level programmable DSP processor and improve the code density, we propose a hierarchical encoding scheme for variable-length instructions. The simulations show that our DSP has comparable performance with state-of-the-art DSP architectures, and the hierarchical instruction encoding saves 31%-64% code sizes compared to the fixed-length instruction encoding.
Symmetric regression quantile and its application to robust estimation for the nonlinear regression model
(2004-12-01)
Chen, LA
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Tran, LT
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Lin, LC
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統計學研究所
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Institute of Statistics
Populational conditional quantiles in terms of percentage alpha are useful as indices for identifying outliers. We propose a class of symmetric quantiles for estimating unknown nonlinear regression conditional quantiles. In large samples, symmetric quantiles are more efficient than regression quantiles considered by Koenker and Bassett (Econometrica 46 (1978) 33) for small or large values of alpha, when the underlying distribution is symmetric, in the sense that they have smaller asymptotic variances. Symmetric quantiles play a useful role in identifying outliers. In estimating nonlinear regression parameters by symmetric trimmed means constructed by symmetric quantiles, we show that their asymptotic variances can be very close to (or can even attain) the Cramer-Rao lower bound under symmetric heavy-tailed error distributions, whereas the usual robust and nonrobust estimators cannot. (C) 2003 Elsevier B.V. All rights reserved.
Triplet exciton formation ratio in poly(p-phenylene-vinylene) light-emitting diode
(2003-04-04)
Lin, LC
;
Meng, HF
;
Shy, JT
;
Horng, SF
;
Yu, LS
The triplet to singlet exciton formation ratio in a poly(2-methoxy-5(2'-ethyl-hexyloxy)-1,4-phenylene vinylene) (MEH-PPV) light-emitting-diode is measured by comparing the triplet induced-absorptions with optical and electric excitations at same singlet exciton density. The ratio is a strong universal decreasing function of the averaged electric field. Using 4 ns for singlet to triplet intersystem crossing time, the ratio is significantly larger than the spin-statistics value 3 at intermediate field but is reduced to about 1 for higher field.
Triplet-to-singlet exciton formation in poly(p-phenylene-vinylene) light-emitting diodes
(2003-01-24)
Lin, LC
;
Meng, HF
;
Shy, JT
;
Horng, SF
;
Yu, LS
The triplet to singlet exciton formation ratio in a MEH-PPV light-emitting diode is measured by comparing the triplet-induced absorptions with optical and electric excitations at the same singlet exciton density. The ratio is a strong universal decreasing function of the averaged electric field. Using 4 ns for singlet to triplet intersystem crossing time, the ratio is significantly larger than the spin-independent value 3 at intermediate field but is reduced to about 2 for higher field.