Browsing by Issue Date, starting with "1997-06-10"

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Proper interval graphs and the guard problem
(1997-06-10)
Chen, CY
;
Chang, CC
;
Chang, GJ
;
應用數學系
;
Department of Applied Mathematics
This paper is a study of the hamiltonicity of proper interval graphs with applications to the guard problem in spiral polygons. We prove that proper interval graphs with greater than or equal to 2 vertices have hamiltonian paths, those with greater than or equal to 3 vertices have hamiltonian cycles, and those with greater than or equal to 4 vertices are hamiltonian-connected if and only if they are, respectively, 1-, 2-, or 3-connected. We also study the guard problem in spiral polygons by connecting the class of nontrivial connected proper interval graphs with the class of stick-intersection graphs of spiral polygons.
The effect of pyrochlore phase on formation mechanism and electrical properties of perovskite PZMN relaxors
(1997-06-15)
Chen, SY
;
Wang, CM
;
Cheng, SY
;
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.
The effect of pyrochlore phase on formation mechanism and electrical properties of perovskite PZMN relaxors
(1997-06-15)
Chen, SY
;
Wang, CM
;
Cheng, SY
;
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.
Suppression of boron penetration by using inductive-coupling-nitrogen-plasma in stacked amorphous/polysilicon gate structure
(1997-06-19)
Yang, WL
;
Lin, CJ
;
Chao, TS
;
Liu, DG
;
Lei, TF
A method is introduced for suppressing the penetration of boron for BF2+-implanted pMOS devices with a stacked amorphous/ poly-Si (SAP) gate structure. It is shown that after inductive-coupling-nitrogen-plasma (ICNP) treatment, boron diffusion through the thin gale oxide is largely suppressed. As shown from the charge-to-breakdown measurements, the ICNP process will improve the quality of pMOS devices, with Q(bd) three times higher than for the control samples.
Overlapped patch elimination algorithm for deformable mesh video coding
(1997-06-19)
Chou, YM
;
Hang, HM
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
Updating mesh nodal points is one of the major tasks in deformable mesh video coding. Owing to object movement and inexact motion estimation, nodal point tracking often results in overlapped patches. A noniterative nodal point processing algorithm is proposed to solve this problem. Simulation results indicate that with this overlapped patch elimination algorithm, the updated mesh can maintain a rather uniform distribution and the moving object can be traced quite well.
An equivalent network method for the analysis of nonuniform periodic structures
(1997-06-20)
Wu, JJ
;
交大名義發表
;
光電工程學系
;
National Chiao Tung University
;
Department of Photonics
The characteristics of guided waves scattered by nonuniform waveguide gratings are systematically investigated with the use of an equivalent network method. This procedure is based on a combination of the multimode network theory and the rigorous mode-matching method. Concave Bragg gratings and bent waveguide gratings are taken as examples to demonstrate the present approach, and numerical results are given to illustrate their potential for millimeter-wave and optical integrated circuit applications. (C) 1997 John Wiley & Sons, Inc.
An equivalent network method for the analysis of nonuniform periodic structures
(1997-06-20)
Wu, JJ
;
光電工程研究所
;
Institute of EO Enginerring
The characteristics of guided waves scattered by nonuniform waveguide gratings are systematically investigated with the use of an equivalent network method. This procedure is based on a combination of the multimode network theory and the rigorous mode-matching method. Concave Bragg gratings and bent waveguide gratings are taken as examples to demonstrate the present approach, and numerical results are given to illustrate their potential for millimeter-wave and optical integrated circuit applications. (C) 1997 John Wiley & Sons, Inc.
Multiobjective zone TP reduction analyses for an off-stream reservoir
(1997-07-01)
Kao, JJ
;
Tsai, CH
;
環境工程研究所
;
Institute of Environmental Engineering
Multiobjective linear programming (MOLP) models are developed to evaluate total phosphorus (TP) load reduction strategies for an off-stream reservoir. Cost, water quality, and equity are the three major objectives considered. Watershed-based, subwatershed-based, and equal-transport-path-length-based strategies are the three zone control strategies analyzed and compared. The agricultural nonpoint-source pollution (AGNSP) model is used to simulate the non-point-source pollution loads on the reservoir, A twostep modeling procedure is applied to verify sediment mass balance and water quality of storm runoff. MOLP models are established based on the simulation results for the three control strategies and are solved using the ADBASE package to generate the noninferior solution sets of the models. The subwatershed-based control strategy is observed to be the most cost-effective one based on results obtained for TP concentration between 13 and 20 ppb, With respect to equity, however, the watershed-based control strategy is superior to the others. The proposed multiobjective analyses are intended to improve the comparison and evaluation of nonpoint source pollution control strategies.
Investigations of pool boiling heat transfer of binary refrigerant mixtures
(1997-07-01)
Chiou, CB
;
Lu, DC
;
Wang, CC
;
機械工程學系
;
Department of Mechanical Engineering
Pool boiling data for binary mixtures of R-22/R-124 on plain tubes are reported at reduced pressures of 0.1, 0.15, and 0.2. Significant reductions of heat transfer coefficients for mixtures are found as compared to pure refrigerant, and the reduction of heat transfer coefficient is especially pronounced in the vicinity of the pore component. This phenomenon is strongly related to the nonlinear variation of physical properties of liquid viscosity and latent heat of the mixtures. The available empirical and semiempirical correlations developed for mixtures are compared with the present data. In addition, a correlation based on the present R-22/R-124 experimental data is proposed. This correlation not only predicts the deterioration of heat transfer coefficients for the present data with success but also predicts the experimental data from other investigators with reasonably good accuracy.
Optical bypassing using a WDM-Gridconnect patchwork
(1997-07-01)
Jager, HA
;
Kao, MS
;
電信工程研究所
;
Institute of Communications Engineering
In this letter, the properties of transparent wavelength routed transport networks are analyzed which are based on a wavelength-divsion multiplexing (WDM)-Gridconnect patchwork and compared to networks built on a conventional fiber infrastructure. The patchwork represents an example of a partitioned wavelength routed fiber-optic transport network using optical bypassing. The cumulative transit traffic and path length statistics are calculated. Based on these results, recommendations for the transparent network partition size and the number of wavelengths are given.
On a pattern-oriented model for intrusion detection
(1997-07-01)
Shieh, SP
;
Gligor, VD
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資訊工程學系
;
Department of Computer Science
Operational security problems, which are often the result of access authorization misuse, can lead to intrusion in secure computer systems. We motivate the need for pattern-oriented intrusion detection, and present a model that tracks both data and privilege flows within secure systems to detect context-dependent intrusions caused by operational security problems. The model allows the uniform representation of various types of intrusion patterns, such as those caused by unintended use of foreign programs and input data, imprudent choice of default privileges, and use of weak protection mechanisms. As with all pattern-oriented models, this model cannot be used to detect new, unanticipated intrusion patterns that could be detected by statistical models. For this reason, we expect that this model will complement, not replace, statistical models for intrusion detection.
Quasi-two-dimensional simulation of scour and deposition in alluvial channels
(1997-07-01)
Lee, HY
;
Hsieh, HM
;
Yang, JC
;
Yang, CT
;
土木工程學系
Most existing sediment routing models are one-dimensional models and hence they cannot be used Co simulate lateral channel bed deformations. Conversely, a two-dimensional model is computationally time consuming, and is not suitable for long-term simulation. Using the stream tube concept, a one-dimensional model is extended to a quasi-two-dimensional model in this study. It is capable of simulating lateral variations of channel cross section through the adjustments of stream tube boundaries. The model has an option to treat the suspended load and bed load separately and hence is able to simulate the deposition behavior of the suspended sediment under a nonequilibrium process. The model also provides options to solve either de Saint Venant equation or energy equation and hence can be applied in both steady and unsteady flow conditions. An assessment of this model's performance has been conducted through a comparison to an analytical solution and a set of experimental data, The application of this model to the Keelung River and the Shiemen Reservoir in Taiwan also gave convincing results.
On computing stable Lagrangian subspaces of Hamiltonian matrices and symplectic pencils
(1997-07-01)
Lin, WW
;
Wang, CS
;
應用數學系
;
Department of Applied Mathematics
This paper presents algorithms far computing stable Lagrangian invariant subspaces of a Hamiltonian matrix and a symplectic pencil, respectively, having purely imaginary and unimodular eigenvalues. The problems often arise in solving continuous- or discrete-time H-infinity-optimal control, linear-quadratic control and filtering theory, etc. The main approach of our algorithms is to determine an isotropic Jordan subbasis corresponding to purely imaginary (unimodular) eigenvalues by using the associated Jordan basis of the square of the Hamiltonian matrix (the S + S-1-transformation of. the symplectic pencil). The algorithms preserve structures and are numerically efficient and reliable in that they employ only orthogonal transformations in the continuous case.
Improved flash cell performance by N2O annealing of interpoly oxide
(1997-07-01)
Jong, FC
;
Huang, TY
;
Chao, TS
;
Lin, HC
;
Leu, LY
In this letter, we report the effects of N2O annealing of interpoly oxide on flash cell performance. It is demonstrated that by adding an N2O anneal after interpoly oxide formation, improved cycling endurance is achieved, The program and erase efficiencies are also improved significantly, compared to the control cell without N2O anneal. The cells with N2O anneal show higher cell current (i.e., drain current), which can be ascribed to a lower threshold voltage and higher transconductance, compared to the control cell.
Investigations of pool boiling heat transfer of binary refrigerant mixtures
(1997-07-01)
Chiou, CB
;
Lu, DC
;
Wang, CC
;
機械工程學系
;
Department of Mechanical Engineering
Pool boiling data for binary mixtures of R-22/R-124 on plain tubes are reported at reduced pressures of 0.1, 0.15, and 0.2. Significant reductions of heat transfer coefficients for mixtures are found as compared to pure refrigerant, and the reduction of heat transfer coefficient is especially pronounced in the vicinity of the pore component. This phenomenon is strongly related to the nonlinear variation of physical properties of liquid viscosity and latent heat of the mixtures. The available empirical and semiempirical correlations developed for mixtures are compared with the present data. In addition, a correlation based on the present R-22/R-124 experimental data is proposed. This correlation not only predicts the deterioration of heat transfer coefficients for the present data with success but also predicts the experimental data from other investigators with reasonably good accuracy.
A novel 3.5-GHz microwave counter using an opto-electronic harmonic heterodyne technique
(1997-07-01)
Chang, CS
;
Chiu, HF
;
交大名義發表
;
光電工程學系
;
National Chiao Tung University
A novel 3.5-GHz microwave counter using an opto-electronic harmonic heterodyne technique has been demonstrated, The system's performance has been discussed and evaluated, and is viewed as good, in comparison with today's microwave-counting systems, It is believed that this novel device has potential for measuring signals above 100 GHz.
An efficient class of weighted trimmed means for linear regression models
(1997-07-01)
Chen, LA
;
統計學研究所
;
Institute of Statistics
We propose and study a class of weighted trimmed means based on the symmetric quantile functions for the location and linear regression models. A robustness comparison with the underlying distribution of a symmetric-type heavy tail is given. The weighted trimmed mean in optimal trimming under symmetric distributions is shown to have an asymptotic variance very close to the Cramer-Rao lower bound. For fixed weight setting, the weighted trimmed mean is still relatively more efficient in terms of asymptotic variance than the trimmed mean based on regression quantiles. From the parametric point of view, the computationally easy weighted trimmed mean is shown to be an efficient alternative to maximum likelihood estimation which is usually computationally difficult for most underlying distributions except the ideal case of normal ones. From the nonparametric point of view, this weighted trimmed mean is shown to be an efficient alternative robust estimator. A methodology for confidence ellipsoids and hypothesis testing based on the weighted trimmed mean is also introduced.
Method of solving a triplet comprising a singlet and a cemented doublet with given primary aberrations
(1997-07-01)
Chen, CH
;
Shiue, SG
;
Lu, MH
;
交大名義發表
;
光電工程學系
A simple algebraic algorithm is proposed as a computational tool for the thin-lens design of a triplet which consists of a singlet and a cemented doublet. The triplet is required to yield specified amounts of lens power, primary spherical aberration, central coma, longitudinal chromatic aberration and secondary spectrum. The three element powers of the triplet are first obtained by solving the simultaneous linear equations of the total lens power, longitudinal chromatic aberration and secondary spectrum. A quadratic equation is obtained by combining the equations of spherical aberration and central coma, and the lens shapes are then obtained by solving this quadratic equation. The solving process is purely algebraic and is therefore easy to calculate and guarantees that all the solutions can be found.
High-performance programmable AC power source with low harmonic distortion using DSP-based repetitive control technique
(1997-07-01)
Tzou, YY
;
Ou, RS
;
Jung, SL
;
Chang, MY
;
交大名義發表
This paper proposes a new control scheme based on a two-layer control structure to improve both the transient and steady-state responses of a closed-loop regulated pulse-width-modulated (PWM) inverter for high-quality sinusoidal ac voltage regulation. The proposed two-layer controller consists of a tracking controller and a repetitive controller. Pole assignment with state feedback has been employed in designing the tracking controller for transient response improvement, and a repetitive control scheme was developed in synthesizing the repetitive controller for steady-state response improvement. Design procedure is given for synthesizing the repetitive controller for PWM inverters to minimize periodic errors induced by rectifier-type nonlinear loads. The proposed control scheme has been realized using a single-chip digital signal processor (DSP) TMS320C14 from Texas Instruments. A 2-kVA PWM inverter has been constructed to verify the proposed control scheme. Total harmonic distortion (THD) below 1.4% for a 60-Hz output voltage under a bridge-rectifier RC load with a current crest factor of 3 has been obtained. Simulation and experimental results show that the DSP-based fully digital-controlled PWM inverter can achieve both good dynamic response and low harmonics distortion.
Normally on reflection-type two-wavelength quantum-well modulator with balanced cavity design
(1997-07-01)
Tsai, CM
;
Lee, CP
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
We have demonstrated a reflection-type two-wavelength modulator with a novel balanced cavity design, Simultaneous operations at wavelengths of around 860 and 896 nm have been achieved. By using such a new cavity design similar operating voltages have been obtained for both wavelengths. Under separate biasing voltages of 14.5 and 11 V on each quantum-well absorbing region, the maximum reflectivity changes were around 50%.