Browsing by Author "Wang, CM"

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3-D polyhedral face computation from two perspective views with the aid of a calibration plate
(1997-04-01)
Chiu, JM
;
Chen, Z
;
Wang, CM
;
資訊科學與工程研究所
;
Institute of Computer Science and Engineering
The 3-D reconstruction of visible polyhedral faces from a pair of general perspective views with the aid of a calibration plate is addressed. A polyhedron is placed on a planar calibration plate and two side views of both the polyhedron and the calibration plate are taken. Through proper arrangements we may assume that in the two views a number of polyhedral edges lying on the calibration plate and the whole calibration plate boundary are visible. We present an on-line camera calibration technique with the aid of the calibration plate and a two-stage process to find the vertex/edge correspondences without encountering the ambiguity problem of the conventional epipolar line technique. Then we give a closed form solution to the 3-D polyhedral vertices visible in both images. We also describe other advantages of using our method for the 3-D polyhedron reconstruction. Experimental results show that the obtained 3-D polyhedral vertex coordinates are rather accurate.
A Web-based data extraction system for supply chain management-using SAP R/3
(2002)
Chen, RS
;
Wang, HC
;
Wang, CM
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資訊管理與財務金融系註：原資管所+財金所
;
Department of Information Management and Finance
This paper presents a prototype of logistics flows and information extraction system between customers and vendors by using World Wide Web (WWW), XML with SAP R/3 programming technology (ABAP/4 Language). Three kinds of benefits are approved for most of the supply chain system. ( 1) To resolve the SAP SAPLPD performance issue existing in the Multi-Bytes Character Print with SAPWIN by developing a HTML Layout Set for the report printout. ( 2) To support business process improvement for customer services, logistics, planning and manufacturing through XML data interface embedded in the software solutions. ( 3) To provide a reliable and scalable information technology infrastructure which could fulfill the requirements of data transparency and data consistency. The result of this paper, we demonstrate an open architecture of data extraction method. It can be used in data transparency and data consistency for a supply chain. Enterprise within multi database can improve the performance of information flows. It can solve data printing problem in many types of layout set to meet the demand of enterpris.
Adaptive path-based multicast on wormhole-routed hypercubes
(2002)
Wang, CM
;
Hou, YM
;
Hsu, LH
;
資訊工程學系
;
Department of Computer Science
In this paper, we consider path-based multicast on wormhole-routed hypercubes. A minimum set of routing restrictions is used as the base routing algorithm. To correctly perform multicast, we present the natural list to sort the destination nodes. It can be proved to be deadlock-free for both one-port and multi-port systems. Furthermore, it creates only one worm for each multicast. Between each pair of nodes in a multicast path with distance k, on the average, there are at least (k+1)!/2(k) adaptive shortest paths, which is superior to previous works. We also propose a heuristic algorithm to reduce the path length. The simulation result shows that its sustainable throughput is much better than related works. In addition, unicast and broadcast can be treated as degenerated cases and use the same routing algorithm. Therefore, it offers a comprehensive routing solution for communication on hypercubes.
Anti-reflection strategies for sub-0.18-mu m dual damascene structure patterning in KrF 248nm lithography
(1999)
Chou, SY
;
Wang, CM
;
Hsia, CC
;
Chen, LJ
;
Hwang, GW
Finding high performance and low cost anti-reflection strategies is a common goal for all photolithographers. This task is getting tough for dual damascene process than the metal-etch process because the oxide thickness variation enhances the thin film interference effect. In this paper, different ARC strategies using organic and inorganic material were examined to compare their CD control performance in sub-0.18 mu m dual damascene structure for KrF 248nm lithography. The organic bottom ARC (BARC) achieves reflectivity control through modulating its thickness. The first and second minimal points in BARC swing curve were chosen as the film thickness to be evaluated. The inorganic ARC, which referred to dielectric ARC (DARC) using PECVD silicon oxynitride (SiOxNy) in this article, was investigated with single layer and double layer structures. The double-layer DARC structure consists of two layers with different extinction coefficient K values. The optimal refractive index (N, K) and thickness of each ARC structure were calculated from some available photolithography simulators. A PECVD process for DARC growth chat provides easily tunable range of refractive index and thickness was established to meet the DW process requirement fr om simulation. The performances of each ARC structure were evaluated on patterning 0.18 mu m trench and 0.20 mu m via in back-end-of-line (BEOL) dual damascene process. It showed that the double-layer DARC provided the most effective CD control ability among these ARC structures. The double-layer DARC should be one of the most potential candidates for sub-0.18 mu m dual damascene process.
Broadcasting on wormhole-routed 2D tori with arbitrary size
(1998)
Hou, YM
;
Wang, CM
;
Tsai, MJ
;
Hsu, LH
;
資訊工程學系
For distributed memory parallel computers, broadcast operations are widely used in a variety of applications. In this paper, we propose an efficient algorithm for broadcasting on an all-port wormhole-routed 2D tents with arbitrary size. The underlying network is assumed to support only the dimension-ordered unicast. By taking the advantage of the all-port model and the distance insensitivity of the wormhole routing, the proposed algorithm can greatly reduce the number of message-passing steps. In addition, it can be proved to be depth contention-free. The performance study in this paper clearly shows the advantage of the proposed algorithm.
Effect of thin film coating of Au on joint strength in Invar-Invar packages
(1996-11-01)
Wang, SC
;
Wang, CM
;
Wang, C
;
Chang, HL
;
Tu, YK
The effect of a thin film coating of Au on the joint strength, weld width, and penetration depth in laser welding techniques for Invar-Invar packages is investigated experimentally. It is found that the joint strength, weld width, and penetration depth are strongly dependent on the coating of Au thickness on the Invar material. The welded joints with thick Au coating show narrower weld width, shallower penetration, and hence less joint strength than those of the packages with thin Au coating. The increase in both the thermal conductivity and the vapor volume in the welded joints as the coating of Au thickness increases are the possible mechanisms for the reduction. Detailed knowledge of the effect of thin film coatings of Au on the welded materials, which gives both the highest joint strength and good adhesion, is essential for practical design and fabrication of reliable optoelectronic packaging.
Effects of dichroic dye in UV-cured polymer dispersed liquid crystal films
(1996-05-01)
Wu, JJ
;
Wang, CM
;
Chen, SH
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光電工程研究所
;
Institute of EO Enginerring
We study the effects of dichroic dye in ''ultraviolet'' polymer dispersed liquid crystal (PDLC) films. Experimental data show that for a dye-doped PDLC film the absorption coefficient for He-Ne laser light is different from that for UV light. Transmittance of a PDLC film changes when the UV curing intensity or dye concentration is varied. It is found that under UV the illumination with a constant intensity the dye concentration can be optimized to obtain minimum transmittance and to improve the contrast ratio. Correspondingly, for a fixed dye concentration the UV curing intensity can be optimized to obtain a minimum transmittance. The experimental results can be described by a theory based on Beer's law. Besides, the experimental results show that the curing temperature is an important factor that affects the nematic liquid crystal droplet size in the UV curing process.
Effects of dichroic dye in UV-cured polymer dispersed liquid crystal films
(1996-05-01)
Wu, JJ
;
Wang, CM
;
Chen, SH
;
光電工程學系
;
Department of Photonics
We study the effects of dichroic dye in ''ultraviolet'' polymer dispersed liquid crystal (PDLC) films. Experimental data show that for a dye-doped PDLC film the absorption coefficient for He-Ne laser light is different from that for UV light. Transmittance of a PDLC film changes when the UV curing intensity or dye concentration is varied. It is found that under UV the illumination with a constant intensity the dye concentration can be optimized to obtain minimum transmittance and to improve the contrast ratio. Correspondingly, for a fixed dye concentration the UV curing intensity can be optimized to obtain a minimum transmittance. The experimental results can be described by a theory based on Beer's law. Besides, the experimental results show that the curing temperature is an important factor that affects the nematic liquid crystal droplet size in the UV curing process.
Electro-optical properties of aligned polymer dispersed liquid crystal films
(1997-07-21)
Wu, JJ
;
Wang, CM
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光電工程學系
;
Department of Photonics
We study the electro-optical properties of polymer dispersed liquid crystal (PDLC) films with various kinds of alignment. These films are transparent in the electric field-on state and opaque in the field-off slate. Experimental data show that the contrast ratio of these aligned films can be higher than that of a usual type PDLC film. The relationship between the field-off state transmittance of such a PDLC film and the polarization of the incident light is discussed. The optical properties of such aligned films can be described by a theory based on Beer's law. (C) 1997 Published by Elsevier Science B.V.
Electrooptical properties of aligned dye-doped polymer dispersed liquid crystal films
(1998-12-01)
Wu, JJ
;
Wang, CM
;
Li, WY
;
Chen, SH
;
光電工程學系
We investigate how plane-parallel and twisted alignment treatments influence the electrooptical properties of dye-doped polymer dispersed liquid crystal (PDLC) films. These films are transparent in the electric field-on state and opaque in the field-off state. The relationship between field-off state transmittance of such dye-doped PDLC films and polarization of the incident light is discussed. Experimental data confirm that, even for unpolarized : Incident light, the contrast ratio of these aligned films surpasses that of a nonaligned dye-doped PDLC film.
Field emission from aligned carbon nanofibers grown in situ by hot filament chemical vapor deposition
(2003-04-14)
Chen, CF
;
Lin, CL
;
Wang, CM
;
材料科學與工程學系
;
Department of Materials Science and Engineering
Aligned high-aspect-ratio carbon nanofibers were grown in situ using modified hot filament chemical vapor deposition. The field-emission properties were then studied. An Fe-Cr wire filament acted as a catalytic source and a heat source. Carbon nanofibers were deposited on a Si substrate with CO2 as a carrier gas through ethanol. The experimental results indicate that the flow in the horizontal direction to the substrate produces carbon nanofibers with diameters of less than 10 nm. The field-emission current of 2 V/mum was 0.54 mA/cm2; the turn-on field of the sample was 1.1 V/mum. (C) 2003 American Institute of Physics.
Field emission properties of vertically aligned carbon nanotubes grown on bias-enhanced hydrogen plasma-pretreated Cr film
(2003-11-01)
Chen, CF
;
Lin, CL
;
Wang, CM
;
材料科學與工程學系
;
Department of Materials Science and Engineering
Using CH4/H-2 source gases, vertically aligned carbon nanotubes were grown on a Cr film by microwave plasma chemical vapor deposition. The Cr film on a silicon wafer had a constant thickness of 100 nm, and bias-enhanced H, plasma pre-treatment was performed for various periods to modify the surface of the Cr film. Bias voltage of - 150 V was applied during both pre-treatment and growth steps, the resultant carbon nanotubes on a Cr film, which had been pretreated in bias-enhanced H-2 plasma for 5 min were vertically aligned. The field emission properties of the resultant carbon nanotubes included an emission current of 0.305 mA at 2 V/mum; and a turn-on field of 1.7 V/mum. (C) 2003 Elsevier B.V. All rights reserved.
Focus latitude enhancement of symmetrical phase mask design for deep submicron contact hole patterning
(2001-11-01)
Chou, SY
;
Lou, JC
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Chen, LJ
;
Shiu, LH
;
Liu, RG
The mechanism of focus latitude enhancement for contact/via hole printing is explained by approximating the axis intensity distribution of an image as a series of cosine functions to characterize the interference between each pair of diffraction beams. It is found that a phase-shifting mask (PSM) with symmetrical assist features improves the depth of focus (DOF) by introducing destructive interference to counterbalance the intensity fluctuation from constructive interference as defocus. A simple formula was derived to represent the capability of focus latitude enlargement. It shows that the extent of enhancement depends on the exposure wavelength and numerical aperture of a projection lens only. Increasing the degree of partial coherence degrades the focal range enlargement because a larger illumination angle elongates the destructive interference pattern in the optical-axis direction to weaken its ability for intensity compensation. On the other hand, the lack of constructive interference in dense hole imaging fails the mask pattern transfer, which limits the application of the phase-shifting method to pattern pitch greater than root2lambda/NA. A tiny amount of spherical aberration results in prominent asymmetrical defocus behavior because the wave deformation in the projection lens shifts the distribution of constructive and destructive interference patterns to opposite defocus directions. The printing characteristics of 0.17 mum contact using an 18% transmission, rim-type attenuated phase-shifting mask are investigated to corroborate our analysis of defocus behavior. The dependence of depth of focus on pattern duty is stressed to elucidate the difference in mechanisms of focus latitude improvements for a sparse hole and periodic dense hole. (C) 2001 American Vacuum Society.
Hot filament for in situ catalyst supply in the chemical vapor deposition growth of carbon nanotubes
(2002-01-15)
Chen, CF
;
Lin, CL
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Wang, CM
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材料科學與工程學系
;
Department of Materials Science and Engineering
A simplified chemical vapor deposition (CVD) method is described for in situ synthesis of multiwalled carbon nanotubes. The synthesis apparatus is similar to, that used to deposit CVD diamond. However, an Fe-Cr wire is selected and coiled as the filament to grow nanotubes. The tubes crow because the filament acts as both a heat source for pyrolysis, and a source of metal for the catalyst. The evaporated metal atoms can be considered to catalyze the growth of carbon nanotubes. The system has the potential to inexpensively synthesize large amounts of nanotubes continuously by combining physical and chemical vapor deposition.
Hot-electron relaxation via optical phonon emissions in GaAs/AlxGa1-xAs quantum well structures: dependence upon the alloy composition and barrier width
(2000-12-01)
Sun, KW
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Chang, HY
;
Wang, CM
;
Wang, SY
;
Lee, CP
We present a systematic investigation of the dependence of the hot-electron-optical-phonon interactions on Al composition and barrier width in GaAs/AlxGa1-xAs MQW structures. Raman scattering measurements at 15 K are presented for samples with different barrier widths and Al composition. The optical phonon energies emitted by the photoexcited electrons in quantum wells were also determined by using hot-electron-neutral acceptor luminescence techniques. It is shown that the relaxation of hot electrons in the quantum wells is dominated by the GaAs LO phonon emission for small x, but by AlAs-like LO phonons for larger Al composition. For samples with larger barriers, the electrons in the GaAs layer relax mostly through the AlAs-like optical phonon emission. However, in samples with smaller barriers, the relaxation of hot electrons is dominated by the GaAs optical phonon emission.
Optical phonon emission in GaAs/AlAs and GaAs/Al0.7Ga0.3As multiple quantum well structures
(2000-12-01)
Sun, KW
;
Wang, CM
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Chang, HY
;
Wang, SY
;
Lee, CP
We have performed Raman scattering measurements and hot electron-neutral acceptor (hot(e, Angstrom)) luminescence experiments on Be-doped GaAs/AlAs and GaAs/Al0.7Ga0.3As multiple quantum well structures, with fixed well width of 50 Angstrom and barrier thickness of 5, 25, 50,120 Angstrom, to determine the optical phonon energy emitted by the hot electrons excited in the quantum wells. It was shown that the relaxation of electrons in the GaAs layer is dominated by the AlAs-like optical phonon emission for samples with larger barriers, but by GaAs optical phonons for smaller barriers. (C) 2001 Elsevier Science B.V. All rights reserved.
Optimal processor mapping for linear-complement communication on hypercubes
(2001-05-01)
Hou, Y
;
Wang, CM
;
Ku, CY
;
Hsu, LH
;
資訊工程學系
In this paper, we address the problem of minimizing channel contention of linear-complement communication on wormhole-routed hypercubes. Our research reveals that, for traditional routing algorithms, the degree of channel contention of a linear-complement communication can be quite large. To solve this problem, we propose an alternative approach, which applies processor reordering mapping at compile time. in this compiler approach, processors are logically reordered according to the given communication(s) so that the new communication(s) can be efficiently realized on the hypercube network. It is proved that, for any linear-complement communication, there exists a reordering mapping such that the new communication has minimum channel contention. An O(n(3)) algorithm is proposed to find such a mapping for an n-dimensional hypercube. An algorithm based on dynamic programming is also proposed to find an optimal reordering mapping for a set of linear-complement communications. Several computer simulations have been conducted and the results clearly show the advantage of the proposed approach.
Raman and hot electron-neutral acceptor luminescence studies of electron-optical phonon interactions in GaAs/AlxGa1-xAs quantum wells
(2000)
Sun, KW
;
Chang, HY
;
Wang, CM
;
Song, TS
;
Wang, SY
Using two optical techniques, we have studied the hot electron-optical phonon interactions in GaAs/AlxGa1-xAs multiple-quantum wells. Raman scattering measurements at 15 K are presented for the Al composition of x = 0.3, 0.5, 0.7 and 1.0. The GaAs-like and AlAs-like phonon frequencies of the first-order modes are also measured as a function of Al composition. The optical phonon energies emitted by the photoexcited electrons in quantum wells are determined by using hot electron-neutral acceptor luminescence techniques. It is shown that the relaxation of hot electrons in the quantum wells is dominated by the GaAs LO phonon emission for small x, but by AlAs-like LO phonons for larger Al composition. (C) 2000 Elsevier Science Ltd. All rights reserved.
Role of perovskite PMN in phase formation and electrical properties of high dielectric Pb[(Mg-x, Zn1-x)(1/3)Nb-2/3]O-3 ceramics
(1998-03-01)
Chen, SY
;
Wang, CM
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Cheng, SY
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材料科學與工程學系
;
Department of Materials Science and Engineering
The structural evolution of perovskite phase Pb[(MgxZn1-x)(1/3)Nb-2/3]O-3 (abbreviated to PZMN) was found to be highly dependent on its precursors' strong tendency of forming pyrochlore phase in the mixture of raw materials. Three major pyrochlore compositions, Pb2Nb2O7, Pb3Nb2O8 and Pb3Nb4O13, were characterized and analyzed to understand their roles in the formation of the perovskite PZMN phase. Based on phase structure evolution, a preparation method for forming high dielectric constant PZMN ceramics without using common stabilizers such as SrTiO3 was proposed. By using pre-synthesized perovskite PMN, a Zn-rich PZMN composition with an almost 100% perovskite content and a maximum dielectric constant of 22 000 at 1 kHz is obtained. The formation mechanism of PZMN perovskite phase was also reported in this research. The pre-synthesized perovskite PMN acts as stabilizer and nuclei to initiate PZMN perovskite formation through the reaction in the PMN/ZnO interface. A ternary phase diagram of PMN-PZN-SrTiO3 was further constructed to investigate the perovskite development and its related electrical properties. (C) 1998 Elsevier Science S.A.
The effect of pyrochlore phase on formation mechanism and electrical properties of perovskite PZMN relaxors
(1997-06-15)
Chen, SY
;
Wang, CM
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Cheng, SY
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材料科學與工程學系
;
Department of Materials Science and Engineering
The reaction mechanism and electrical properties of phase formation of the perovskite Pb[(Mg-x,Zn1-x)(1/3)Nb-2/3]O-3-SrTiO3 (PZMN-ST) were studied. Three major pyrochlore phase types, Pb2Nb2O7, Pb3Nb2O8 and Pb3Nb4O13 were characterized and analyzed to understand their roles in the formation of perovskite PMN, PZN and PZMN phases. The formation of a perovskite phase within PMN relaxors requires the presence of either Pb2Nb2PO7 or Pb3Nb2O8 pyrochlore phases in the mixture and is only slightly dependent on the presence of the stabilizer. On the other hand, the formation of a perovskite phase within PZN or PZMN relaxors requires the presence of both Pb3Nb2O8 pyrochlore phase and stabilizer. The maximum dielectric constant for PMN, PZN and PZMN systems can be obtained with the Pb3Nb2O8 phase present in the starting raw materials because of the benefit of Pb3Nb2O8 to perovskite phase formation.