Browsing by Author "Hsu, HC"

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A bandwidth and memory efficient MPEG-4 shape encoder
(2004)
Lee, KB
;
Chang, NYC
;
Chin, HY
;
Hsu, HC
;
Jen, CW
We have developed a shape encoder hardware for MPEG-4 video coding. On the one hand, the alpha component is compressed and therefore, the size and memory access of alpha frame memory can be reduced to 50% and 56.25% respectively. On the other hand, an efficient data transfer scheme combining the run length coding and addressing mode can reduce average data transfer time to 9.39% and accelerate the shape encoding process. The shape encoder can support MPEG-4 Main Profile at Level 4 in real-time. In addition, verification and testing methods are also considered.
A cost-effective MPEG-4 shape-adaptive DCT with auto-aligned transpose memory organization
(2004)
Lee, KB
;
Hsu, HC
;
Jen, CW
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
This paper presents an efficient VLSI architecture of shape-adaptive discrete cosine transform (SA-DCT) for MPEG-4. The proposed architecture contains a cost-effective 1-D variable-length DCT engine and an auto-aligned transpose memory organization. Compared to other designs for SA-DCT, our architecture requires fewer multipliers whereas has higher throughout. Together with address generators and address pointers, the auto-aligned transpose memory organization can achieve transposing, shifting and aligning simultaneously without saving shape information. When clocking at 66.7 MHz, the proposed architecture has a throughput of 43.83 Mpixels/sec.
A sonority model of syllable contraction in Taiwanese Southern Min
(2003-10-01)
Hsu, HC
;
外國語文學系
;
Department of Foreign Languages and Literatures
This paper reexamines syllable contraction in Taiwanese Southern Min. Grounded on Chung's (1996) autosegmental model, the current analysis is characterized by Six points: (a) Every syllable has an XXX template. (b) Edge-in (Yip 1988) takes care of the association fo edge consonants with edge skeletal slots. (c) The realization of the nucleus abides by the order of N-placement, rising diphthong formation, and falling diphthong formation. (d) The sonority hierarchy of a > superset of > e > o > i > u determines how vocoids are associated with the nucleus position. if there is a tie, the first segment gets linked by temporal sequence. V-neutralization (Chung 1969 turns mid vowels into high when they form rimes with the adjacent vowels. (e) The contracted form abides by Maximality (Prince 1985) to construct the largest possible syllable. (f) In addition, stress is shown irrelevant, and phonotactic constraints may be contravened.
An optimality-theoretic analysis of syllable contraction in Cantonese
(2005-01-01)
Hsu, HC
;
交大名義發表
;
National Chiao Tung University
As a departure from Cheung's (1986) rule-based study on syllable contraction in Cantonese, the present analysis employs the notion of constraint interaction in Optimality Theory (Prince and Smolensky 1993) to solve the critical issue concerning the prediction of the output nucleus. Distinct from the sonority-oriented dialects such as Taiwanese Southern Min, Hakka, and Taiwan Mandarin, Cantonese is characterized by the determination of output nucleus by vowel length. In Optimality Theory, language variation appeals to different ranking of a set of universal constraints. This paper also illustrates that as a product of fast speech, syllable contraction may not follow language-specific phonotactic constraints.
Architecture design of MPEG-4 texture decoder - Supporting object-based video coding
(2005)
Hsu, HC
;
Chang, NYC
;
Chang, TS
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
Handling of the complexity which arises due the irregularity data nature for MPEG-4 object based video coding is an important issue in MPEG-4 texture decoder design. Another crucial issue is designing an efficient architecture to satisfy the resource sensitive nature of portable embedded video codec systems. This paper presents an architecture for texture decoding to address these two major issues. By adopting zero-skipping and zero index tables together, the throughput and power consumption are improved significantly. To avoid incurring extra hardware overhead, multiplication sharing and buffer sharing are also incorporated. ne synthesized design can perform texture decoding of CIF@30FPS under 2.18 MHz. using UMC 0.181 mu m 1P6M technology, the reported power consumption is 0.92 mW.
Band gap engineering and spatial confinement of optical phonon in ZnO quantum dots
(2006-06-26)
Lin, KF
;
Cheng, HM
;
Hsu, HC
;
Hsieh, WF
;
光電工程學系
Both band gap engineering and spatial confinement of optical phonon were observed depending upon the size of ZnO quantum dots at room temperature. Size-dependent blueshifts of photoluminescence and absorption spectra reveal the quantum confinement effect. The measured Raman spectral shift and asymmetry for the E-2(high) mode caused by localization of optical phonons agree well with that calculated by using the modified spatial correlation model. (c) 2006 American Institute of Physics.
Band gap variation of size-controlled ZnO quantum dots synthesized by sol-gel method
(2005-06-30)
Lin, KF
;
Cheng, HM
;
Hsu, HC
;
Lin, LJ
;
Hsieh, WF
ZnO quantum dots were synthesized successfully via a simple sol-gel method. The average size of quantum dots can be tailored using well-controlled concentration of zinc precursor. Size-dependent blue shifts of photoluminescence and absorption spectra revealed the quantum confinement effect. The band gap enlargement is in agreement with the theoretical calculation based on the effective mass model. Furthermore, as the particle size decreases, we observed an increase in the size-dependent Stokes shift of the photoluminescence peak relative to the absorption onset. (c) 2005 Elsevier B.V. All rights reserved.
Effect of annealing on the structural and optical properties of AgGaS2 thin films prepared by pulsed laser deposition
(2002-11-01)
Hsu, HC
;
Chen, HH
;
Kuo, SY
;
Chang, CS
;
Hsieh, WF
The influence of annealing on the AgGaS2 films groom by pulsed laser deposition has been investigated. The X-ray diffraction results show the AgGaS2 films were found with preferential orientation (1 1 2) normal to the surface and silver droplets,were diminished after the post-annealing. Photoluminescence (PL) measurements reveled the exciton energy is slightly red shifted that is possibly due to the thermal strain effect. The binding energy of the shallow, donors is similar to28 meV determined from temperature dependent PL spectra, In addition, the A-exciton and the B/C-exciton could be observed in the transmittance spectra at room temperature. (C) 2002 Elsevier Science B.V. All rights reserved.
Efficient UV photoluminescence from monodispersed secondary ZnO colloidal spheres synthesized by sol-gel method
(2005-04-15)
Cheng, HM
;
Hsu, HC
;
Chen, SL
;
Wu, WT
;
Kao, CC
ZnO colloidal spheres were synthesized by sol-gel method with a narrow size distribution. We controlled the size of the spheres during the secondary reaction with various amounts of primary reaction supernatant. The optimized condition of ZnO powders with an average diameter of 185 nm was obtained for structure analysis and study of optical properties. Transmission electron microscopy and X-ray diffraction reveal that the spheres are polycrystalline in the pure wurtzite phase. Markedly enhanced near-band-edge ultraviolet pbotoluminescence and significantly reduced defect-related visible emission were also observed. We attribute this observation to the localized bound excitons with high density of defect states. In addition, broad yellow emission and green emission were observed when the powders were post-annealed at 500 degrees C in air ambience. The origins of the defect-induced visible emissions are attributed to oxygen interstitials and oxygen vacancies. (c) 2005 Elsevier B.V. All rights reserved.
Electrostatic discharge implantation to improve machine-model ESD robustness of stacked NMOS in mixed-voltage I/O interface circuits
(2003)
Ker, MD
;
Hsu, HC
;
Peng, JJ
;
電機學院
;
College of Electrical and Computer Engineering
A novel electrostatic discharge (TSD) implantation method is proposed to significantly improve machine-model (MM) ESD robustness of NMOS device in stacked configuration (stacked NMOS). By using this ESD implantation method, the ESD current is discharged far away from the surface channel of NMOS, therefore the stacked NMOS in the mixed-voltage I/O interface can sustain a much higher ESD level, especially under the MM ESD stress. The MM ESD robustness of the stacked NMOS with a device dimension of W/L=300mum/0.5 mum for each NMOS has been successfully improved from the original 358 V to become 491 V in a 0.25-mum CMOS process. This ESD implantation, method with the n-type impurity is fully process-compatible to general sub-quarter-micron CMOS processes.
Enhanced resonant Raman scattering and electron-phonon coupling from self-assembled secondary ZnO nanoparticles
(2005-10-06)
Cheng, HM
;
Lin, KF
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Hsu, HC
;
Lin, CJ
;
Lin, LJ
Self-assembled secondary ZnO nanoparticles, recognized with the agglomeration of crystalline subcrystals, are successfully synthesized by a simple sol-gel method. TEM images display that one artificial cluster behaves in a single-crystal-like wurtzite structure because subcrystals coagulate as the same crystal orientation. Moreover, from the resonant Raman scattering, the as-grown sample exhibits phonon red shift; meanwhile, the coupling strength between electron and longitudinal optical phonon, determined by the ratio of second to first-order Raman scattering cross sections, diminishes compared with the samples after postannealing at 350 and 500 degrees C. The size dependence of electron-phonon coupling is principally as a result of the Frohlich interaction.
ESD implantation for subquarter-micron CMOS technology to enhance ESD robustness
(2003-10-01)
Ker, MD
;
Hsu, HC
;
Peng, JJ
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電機學院
;
College of Electrical and Computer Engineering
A new electrostatic discharge (ESD) implantation method is proposed to significantly improve ESD robustness of CMOS integrated circuits in subquarter-micron CMOS processes, especially the machine-model (MM) ESD robustness. By using this method, the ESD current is discharged far away from the surface channel of nMOS, therefore the nMOS (both single nMOS and stacked nMOS) can sustain a much higher ESD level. The MM ESD robustness of the gate-grounded nMOS with a device dimension width/length (W/L) of 300 mum/0.5 mum has been successfully improved from the original 450 V to become 675 V in a 0.25-mum CMOS process. The MM ESD robustness of the stacked nMOS in the mixed-voltage I/O circuits with a device dimension W/L of 300 mum/0.5 mum for each nMOS has been successfully improved from the original 350 V to become 500 V in the same CMOS process. Moreover, this new ESD implantation Method with the n-type impurity can be fully Merged into the general subquarter-micron CMOS processes.
ESD protection design for mixed-voltage I/O buffer with substrate-triggered circuit
(2005-01-01)
Ker, MD
;
Hsu, HC
;
電機學院
;
College of Electrical and Computer Engineering
A substrate-triggered technique is proposed to improve the electrostatic discharge (ESD) robustness of a stacked-nMOS device in the mixed-voltage I/O circuit. The substrate-triggered technique can further lower the trigger voltage of a stacked-nMOS device to ensure effective ESD protection for mixed-voltage I/O circuits. The proposed ESD protection circuit with substrate- triggered design for a 2.5-V/3.3-V-tolerant mixed-voltage I/O circuit has been fabricated and verified in a 0.25-mum salicided CMOS process. The substrate-triggered circuit for a mixed-voltage I/O buffer to meet the desired circuit application in different CMOS processes can be easily adjusted by using HSPICE simulation. Experimental results have confirmed that the human-body-model (HBM) ESD robustness of a mixed-voltage I/O circuit can be increased similar to60% by this substrate-triggered design.
ESD protection design for mixed-voltage-tolerant I/O buffers with substrate-triggered technique
(2003)
Ker, MD
;
Hsu, HC
;
電機學院
;
College of Electrical and Computer Engineering
A substrate-triggered technique is proposed to improve ESD protection efficiency of the stacked-NMOS device in the mixed-voltage I/O circuit. The substrate-triggered technique can further lower the trigger voltage of the stacked-NMOS device to ensure effective ESD protection for the mixed-voltage I/O circuit. The proposed ESD protection circuit with the substrate-triggered technique for 2.5V/3.3V tolerant mixed-voltage I/O circuit has been fabricated and verified in a 0.25-mum salicided CMOS process. Experimental results have confirmed that the HBM ESD robustness of the mixed-voltage I/O circuit can be increased similar to60% by this substrate-triggered design.
Excitonic polaron and phonon assisted photoluminescence of ZnO nanowires
(2004-08-01)
Hsu, HC
;
Hsieh, WF
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光電工程學系
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Department of Photonics
The coupling strength of the radiative transition of hexagonal ZnO nanowires to the longitudinal optic (LO) phonon polarization field is deduced from temperature dependent photoluminescence spectra. An excitonic polaron formation is discussed to explain why the interaction of free excitons with LO phonons in ZnO nanowires is much stronger than that of bound excitons with LO phonons. The strong exciton-phonon coupling in ZnO nanowires affects not only the Haung-Ray S factor but also the FXA-ILO phonon energy spacing, which can be explained by the excitonic polaron formation. (C) 2004 Elsevier Ltd. All rights reserved.
Fabrication and optical property of GaSe thin films grown by pulsed laser deposition
(2003-08-01)
Lee, SH
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Hsu, YK
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Hsu, HC
;
Chang, CS
;
Hsieh, WF
The highly oriented (001) GaSe film on c-cut sapphire (0001) was successfully fabricated by pulsed laser deposition. As growth temperature decreases from 550degreesC to 375degreesC, the structure of films changes from cubic zinc-blende Ga2Se3 phase to GaSe phase. The growth temperature of the critical transition from Ga2Se3 phase to GaSe phase is around 500degreesC . From atomic force microscope (AFM) results, it is observed that the growth process of GaSe film is in the manner of layer plus island growth. Besides, the optimal growth conditions of as-grown GaSe film were obtained at a substrate temperature of 400degreesC and laser energy density of 11.7J/cm(2). When the thickness of films goes beyond 800 Angstrom, the stress will be released and the thickness of 1200 Angstrom results in an optimal GaSe film. Furthermore, the indirect bound exciton emission and the recombination via impurity levels or structural defects were observed from low-temperature photoluminescence measurement.
Fault Hamiltonicity and fault Hamiltonian connectivity of the (n, k)-star graphs
(2003-12-01)
Hsu, HC
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Hsieh, YL
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Tan, JJM
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Hsu, LH
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資訊工程學系
In this paper, we consider the fault Hamiltonicity, and the fault Hamiltonian connectivity of the (n, k)-star graph S-n,S-k. Assume that F subset of V(S-n,S-k) boolean OR E(S-n,S-k). For n - k greater than or equal to 2, we prove that S-n,S-k - F is Hamiltonian if F less than or equal to n - 3 and S-n,S-k - F is Hamiltonian connected if F less than or equal to n - 4. For n - k = 1, S-n,S-n-1 is isomorphic to the n-star graph S-n which is known to be Hamiltonian if and only if n > 2 and Hamiltonian connected if and only if n = 2. Moreover, all the bounds are tight. (C) 2003 Wiley Periodicals, Inc.
Fault hamiltonicity and fault hamiltonian connectivity of the arrangement graphs
(2004-01-01)
Hsu, HC
;
Li, TK
;
Tan, JJM
;
Hsu, LH
;
資訊工程學系
The arrangement graph A(n,k) is a generalization of the star graph. There are some results concerning fault Hamiltonicity and fault Hamiltonian connectivity of the arrangement graph. However, these results are restricted in some particular cases and, thus, are less completed. In this paper, we improve these results and obtain a stronger and simpler statement. Let n - k greater than or equal to 2 and F subset of or equal to V(A(n,k)) boolean OR E(A(n,k)). We prove that A(n,k) - F is Hamiltonian if F less than or equal to k(n - k) - 2 and A(n,k) - F is Hamiltonian connected if F less than or equal to k(n - k) - 3. These results are optimal.
Luminescence of selective area growth of epitaxial ZnO nanowires and random-growth-oriented nanobelts
(2006-03-14)
Hsu, HC
;
Cheng, HM
;
Wu, CY
;
Huang, HS
;
Lee, YC
Epitaxial ZnO nanowires and random-growth-oriented nanobelts were grown on c-plane sapphire with and without a pre-coated ZnO epilayer film. On the pre-coated ZnO epilayer, ZnO nanowires are vertically aligned with good in-plane alignment as a result of homoepitaxy, whereas on the bare c-plane sapphire, besides a few nanowires vertically aligned with [0001]znO parallel to [0001](Al2O3), the nanowires were properly aligned with three-fold rotation symmetry. The ZnO nanowires are well-defined hexagonal crystals with diameters of 70-500 nm and lengths of up to several micrometres. In the junction regions between the pre-coated epilayer and the bare sapphire surface, however, ZnO nanobelts (nanoribbons) were found. Cathodoluminescence measurements revealed that the emission at 3.26 eV is correlated with free-exciton recombination and the broad green emission at 2.48 eV is attributed to surface defects. The stronger green emission implies that more surface defects exist on the side walls of nanowires and nanobelts. In Raman scattering, the E1 (LO) mode is sensitive to the orientation of nanostructure that is consistent with the cathodoluminescence results.
Methods to improve machine-model ESD robustness of NMOS devices in fully-salicided CMOS technology
(2005)
Hsu, HC
;
Chen, CM
;
Ker, MD
;
電機學院
;
College of Electrical and Computer Engineering
NMOS with dummy-gate structure is proposed to significantly improve machine-model (MM) electrostatic discharge (ESD) robustness in a fully-salicided CMOS technology. By using this structure, the ESD current is discharged far away from the salicided surface channel of NMOS, therefore NMOS can sustain a much higher ESD level, especially under the machine-model ESD stress.