Browsing by Issue Date, starting with "1995-04-28"

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COMPACT EMBEDDING OF BINARY-TREES INTO HYPERCUBES
(1995-04-28)
CHEN, CC
;
CHEN, RJ
;
資訊工程學系
;
Department of Computer Science
COGNITIVE-MAP-BASED DECISION-ANALYSIS BASED ON NPN LOGICS
(1995-04-28)
CHEN, SM
;
交大名義發表
;
資訊工程學系
;
National Chiao Tung University
;
Department of Computer Science
This paper presents a new method for cognitive-map-based decision analysis based on negative-positive-neutral (NPN) logics, where an efficient algorithm is proposed for performing interval-based inexact reasoning automatically. The algorithm performs inexact reasoning via constructing a sprouting tree. The time complexity of the proposed algorithm is O(nm), where n is the number of cognitive units in the cognitive map, m is the length of a closure path, and max(m) = 2n.
AN OBJECT-ORIENTED APPROACH TO CONSTRUCTING COMMUNICATION PROTOCOLS
(1995-05-01)
CHEN, JL
;
WANG, FJ
;
TING, YC
;
交大名義發表
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資訊科學與工程研究所
The development of communication protocols for computer networks and distributed systems is an increasingly complex and cost-sensitive process. This paper presents an object-oriented concurrent (OOC) model for the development of communication protocols. This model consists of three kinds of entities: data entities, which represent the communicated data units, state entities, which describe their behavior, and connection, entities, which are responsible for communication services. The state transitions in a protocol are modeled by using state entities, and a communication service is performed by a group of connection and state entities. A C++ library based on our OOC model is described that contains three class hierarchies, for data, state; and connection entities, respectively In addition, an approach to constructing a protocol using this OOC model and the library is presented. An example in which a T.62 protocol is constructed shows that this approach provides a high level of modeling, concurrency, and reusability.
A CMOS TRANSISTOR-ONLY 8-B 4.5-MS/S PIPELINED ANALOG-TO-DIGITAL CONVERTER USING FULLY-DIFFERENTIAL CURRENT-MODE CIRCUIT TECHNIQUES
(1995-05-01)
WU, CY
;
CHEN, CC
;
CHO, JJ
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
Fully-differential current-mode circuit techniques are developed for the design of a pipelined current-mode analog-to-digital converter (IADC) in the standard CMOS digital processes. In the proposed IADC, the 1-b-per-stage architecture based on the reference nonrestoring algorithm is adopted. Thus large component ratios can be avoided and the linearity errors caused by device mismatches can be minimized. As one of the key subcircuits in the IADC, an offset-canceled high speed differential current comparator (CCMP) is proposed and analyzed. In the CCMP, the subtractions of offsets are performed in the current domain without floating capacitors. Moreover, the other key subcircuit, the current sample-and-hold amplifier (CSHA), is also developed to realize the pipeline architecture. An experimental chip for the proposed IADC has been fabricated in 0.8-mu m n-well CMOS technology. Using a single 5-V power supply, the fabricated IADC can be operated at 4,5-Ms/s conversion rate with a signal-to-noise-and-distortion-ratio (SNDR) of 51 dB (effective 8.2-b) for the input signal at 453 kHz. For 8-b resolution, the fabricated IADC can be operated at 4,5-Ms/s conversion rate with both differential nonlinearity (DNL) and integral nonlinearity (INL) below +/-0.6 LSB. The power consumption and the active chip area are 16 mW/b and 0.73 mm(2)/b, respectively.
AN ULTRA-LOW COST AND MINIATURE 950-2050 MHZ GAAS MMIC DOWNCONVERTER .1. DESIGN APPROACH AND SIMULATION
(1995-05-01)
HSIEH, TH
;
WANG, H
;
WANG, TH
;
CHEN, TH
;
CHIANG, YC
A miniature ultra low cost 950-2050 MHz GaAs MMIC downconverter has been designed for satellite TV application using a 1-mu m gate-length, ion-implanted GaAs MESFET foundry process. To accurately predict circuit performances, both linear and nonlinear equivalent circuit models have been developed to characterize the RF and de behaviors of device. Modeled simulation results show correspondence with the experimental data. This monolithic downconverter is comprised of an RF LNA, a dual-gate MESFET mixer, an IF variable gain amplifies and a varactor tuned oscillator. The primary design specifications are (1) 50-dB conversion gain, (2) 4-dB noise figure, (3) more than 40-dB gain controllable range, and (4) 50-dBc third-order intermodulation distortion. The chip size is 1.4 x 1.5 x 0.18 mm(3). It is encapsulated in a standard low cost mm plastic package. Moreover, this downconverter IC is promising for miniaturization and cost-reduction of a DBS receiver The detailed measured characteristics will be presented in part-II of this paper.
COMPLETELY SELF-STARTING PICOSECOND AND FEMTOSECOND KERR-LENS MODE-LOCKED TI-SAPPHIRE LASER
(1995-05-01)
SHIEH, JM
;
GANIKHANOV, F
;
LIN, KH
;
HSIEH, WF
;
PAN, CL
Completely self-starting and stable operation of a Kerr-lens mode-locked Ti:sapphire laser was realized in both picosecond and femtosecond regimes. The cavity has a symmetric X configuration with soft aperturing. Enhanced Kerr nonlinearity and reduced backscattering effects were thought to be key to obtaining stable self-starting self-mode-locked operation from 765 to 815 nm far the picosecond regime and from 770 to 835 nm for the femtosecond regime. The mode-locking starting time as measured by the onset of the second-harmonic signal ranged from 300 ms to 2 s, depending on cavity alignment. Preliminary data also suggest that intracavity intensity fluctuation necessary for the laser to evolve into stable mode locking could be as short as 10-40 ps.
STRONG ENHANCEMENT OF THE OPTICAL AND ELECTRICAL-PROPERTIES, AND SPONTANEOUS FORMATION OF AN ORDERED SUPERLATTICE IN (111)B ALGAAS
(1995-05-01)
CHIN, A
;
LIN, HY
;
HSIEH, KY
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
Strong enhancement in the luminescence intensity is observed in Al0.22Ga0.78As epitaxial layers grown on misoriented (111)B GaAs as compared to those simultaneously grown on (100) GaAs. For a 1 degrees misorientation the luminescence intensity is almost 10 to 1000 times that of the (100) layers, depending on the growth temperature. Room temperature electron mobility for 3 degrees misoriented (111)B Al0.18Ga0.82As is 19% higher than that for side-by-side grown (100). The strong luminescence associated with a large red shift of 90 meV and the 19% mobility enhancement are related to the long range composition ordering in (111)B AlGaAs, which is observed by cross-sectional transmission electron microscopy in a 280 Angstrom Al0.4GaAs quantum well heterostructure with Al0.7GaAs barriers grown on (111)B GaAs substrates.
SHIELDING EFFECT OF A DIAPHRAGM IN A PACKAGED MICROSTRIP CIRCUIT
(1995-05-01)
CHEN, HH
;
CHUNG, SJ
;
交大名義發表
;
電信工程研究所
;
National Chiao Tung University
The scattering of a diaphragm in a packaged microstrip line is investigated using the mode-matching method together with the method of lines. Instead of analyzing the discontinuity in the microstrip, this paper tackles the variation of the waveguide housing, The influences of the thickness and the depth of the diaphragm on the scatterings of the dominant mode and higher-order modes are analyzed based on a comparison of the modal power distributions, Finally, the shielding effect of a pair of closely spaced diaphragms is investigated.
DOCUMENT-RETRIEVAL USING KNOWLEDGE-BASED FUZZY INFORMATION-RETRIEVAL TECHNIQUES
(1995-05-01)
CHEN, SM
;
WANG, JY
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資訊工程學系
;
Department of Computer Science
A knowledge-based approach for fuzzy information retrieval is proposed, where interval queries and weighted-interval queries are allowed for document retrieval, In this paper, knowledge is represented by a concept matrix, where the elements in a concept matrix represent relevant values between concepts, The implicit relevant values between concepts are inferred by the transitive closure of the concept matrix based on fuzzy logic. The proposed method is more flexible than the ones presented in [6] and [11] due to the fact that it has the capability to deal with interval queries and weighted-interval queries.
A NOVEL CORDIC-BASED ARRAY ARCHITECTURE FOR THE MULTIDIMENSIONAL DISCRETE HARTLEY TRANSFORM
(1995-05-01)
GUO, JI
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LIU, CM
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JEN, CW
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資訊工程學系
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電控工程研究所
In this paper, a coordinate rotation digital computer (CORDIC)-based array architecture is presented for computing the multidimensional (M-D) discrete Hartley transform (DHT). Since the kernel of the M-D DHT is inseparable, the M-D DHT problems cannot be computed through the 1-D DHT's directly. Bracewell et al. have presented an algorithm for the M-D DHT through the 1-D DHT's. The existing hardware architectures have been designed using this algorithm. However, the postprocessing required in the algorithm leads to high hardware overhead. This paper presents a new algorithm to compute M-D DHT through a special 1-D transform which is derived through considering both the separable computation and the efficient implementation with CORDIC architectures. This algorithm provides a direct way to compute the M-D DHT separably through 1-D transforms with simpler postprocessing than that in Bracewell's approach. Also, the algorithm exploits the symmetry of the triangular functions to reduce the computational complexity. Using this algorithm, we design an array architecture for the M-D DHT. This architecture features a systolic computing style, PE's with a CORDIC structure, low I/O cost, and the encapsulated new M-D DHT algorithm.
BOLOMETRIC RESPONSE OF HIGH-T-C SUPERCONDUCTING DETECTORS TO OPTICAL PULSES AND CONTINUOUS WAVES
(1995-05-01)
CHEN, RC
;
WU, JP
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CHU, HS
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交大名義發表
;
機械工程學系
This work presents a thermal analysis on predicting the temperature increase and the voltage response of high-T-c superconducting bolometers. Two heat transfer models, that is, the surface heating model and the heat generation model considering the skin depth, are introduced and compared. The surface heating model is found to be valid only for situations where the skin depth is much smaller than the film thickness. To consider the thermal boundary resistance between film and substrate, a radiation-boundary-condition model based on acoustic mismatch model (AMM) and an interfacial-layer model (ILM) are employed. The thermal boundary resistance significantly influences the voltage response. Additionally, several common substrates are examined. SrTiO3 (100) or LaAlO3 (100) is a better substrate for high-T-c superconducting bolometers. One interesting finding was that when compared with experimental data, all the theoretical values from the present study as well as the other previously theoretical treatment overestimate the voltage response near the transition temperature.
A NOVEL EXTRACTION TECHNIQUE FOR THE EFFECTIVE CHANNEL-LENGTH OF MOSFET DEVICES
(1995-05-01)
LI, HH
;
WU, CY
;
電控工程研究所
;
Institute of Electrical and Control Engineering
A novel method using the charge pumping technique for extracting the effective channel length of MOSFET devices is presented, in which the effective area approach is used and the edges of the area are defined clearly. It is shown that the extracted effective channel length is independent of the measuring biases and the proposed new method is simple, accurate, and reliable, as compared to those using the I-V method. With the knowledge of the device dopant profiles, the extracted channel length with 0.01 mu m accuracy can be achieved. Moreover, the proposed method is applicable to either n- or p-channel, conventional or LDD, surface or buried channel MOSFET's.
AN IMPLEMENTATION OF AN EXTERNAL PAGER INTERFACE ON BSD UNIX
(1995-05-01)
WANG, HH
;
LU, PK
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CHANG, RC
;
資訊工程學系
;
Department of Computer Science
We have designed and implemented an external pager facility on the ConvexOS for Convex supercomputers to enhance memory management capability within the kernel. A group of generic interfaces that can be used to construct a memory manager at user level is proposed. Furthermore, a highly modularized subsystem that provides dynamic configuration and portability is presented.
ESTIMATION OF UNIT-HYDROGRAPH BY RIDGE LEAST-SQUARES METHOD
(1995-05-01)
ZHAO, B
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TUNG, YK
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YANG, JC
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土木工程學系
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Department of Civil Engineering
Least squares (LS) methods are frequently used to determine an optimal unit hydrograph (UH) for a watershed. However, the conventionally used ordinary LS method could potentially produce a UH with unwanted fluctuation among hydrograph ordinates. When that occurs, the ridge LS method can be used to reduce noise fluctuation in a derived UH. In the framework of the ridge LS method, a UH can be obtained by minimizing the mean-squared error (MSE) of the estimated UH or direct runoff hydrograph (DRH). Therefore, the ridge LS method theoretically would enhance the predictability of the derived UH. This paper describes methodologies of obtaining the optimal ridge parameter for use in the ridge LS method to estimate a UH. Furthermore, the unit volume constraint is considered in the determination of the optimal ridge parameter. A statistical validation study is also conducted to show that a UH obtained by the ridge LS method has a better predictive capability than the one derived by the ordinary LS method.
LEAST-SQUARES SOLUTION FOR DANGLING-LINE CASE IN CADASTRAL-MAP RESURVEY
(1995-05-01)
SHIH, TY
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交大名義發表
;
土木工程學系
;
National Chiao Tung University
;
Department of Civil Engineering
A variety of practical problems have been experienced in the cadastral-map resurvey in Taiwan. One of them concerns the dangling boundary lines shared with a number of land parcels. Conventionally, this problem is resolved subjectively by the operator via graphic tools. An alternative solution based on the least-squares principle, thereby offering an objective means of assessment, is proposed and described in this study. The normal representation of a line is used to parameterize boundary segments. This formulation avoids the difficulty encountered with other representations, such as the slope-intercept equation. The formulation stated in this paper still remains nonlinear with respect to the unknown parameter(s). However, the convergence is quite stable in all numerical experiments conducted so far. Both the two-parameter and one-parameter cases are discussed.
EFFECTS OF PRESSURE ON THE FORMATION OF PHOSPHORUS-DOPED MICROCRYSTALLINE SILICON FILMS DEPOSITED BY RADIO-FREQUENCY GLOW-DISCHARGE
(1995-05-01)
FENG, MS
;
LIANG, CW
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材料科學與工程學系
;
電子工程學系及電子研究所
;
奈米中心
A HEURISTIC ALGORITHM FOR THE RELIABILITY-ORIENTED FILE ASSIGNMENT IN A DISTRIBUTED COMPUTING SYSTEM
(1995-05-01)
CHEN, DJ
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HOL, WC
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CHEN, RS
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CHEN, DTK
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資訊科學與工程研究所
Distributed Computing Systems (DCS) have become a major trend in today's computer system design because of their high speed and high reliability. Reliability is an important performance parameter in DCS design. Usually, designers add redundant copies of software and/or hardware to increase the system's reliability. Thus, the distribution of data files can affect the program reliability and system reliability. The reliability-oriented file assignment problem is to find a file distribution such that the program reliability or system reliability is maximized. In this paper, we develop a heuristic algorithm for the reliability-oriented file assignment problem (HROFA), which uses a careful reduction method to reduce the problem space. Our numerical results indicate that the HROFA algorithm obtains the exact solution in most cases and the computation time is significantly shorter than that needed for an exact method. When HROFA fails to give an exact solution, the derivation from the exact solution is very small.
FOURIER-TRANSFORM INFRARED SPECTROSCOPIC STUDY OF OXIDE-FILMS GROWN IN PURE N2O
(1995-05-01)
CHAO, TS
;
CHEN, WH
;
LEI, TF
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電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
The properties of the oxide films grown by pure N2O were studied in this work. A two-layer model, considering a N2O oxide with an oxy-nitride film at the interface, was used to describe the dependence of the main peak shift in a Fourier transform infrared (FTIR) spectrum on N2O thicknesses. The thickness of interfacial layer was determined by FTIR and multiple-angle incident ellipsometer. Both methods showed consistent results and the thickness of this layer is found to be 14-16 Angstrom.
THIN POLYOXIDE ON THE TOP OF POLY-SI GATE TO SUPPRESS BORON PENETRATION FOR PMOS
(1995-05-01)
LIN, YH
;
LEE, CL
;
LEI, TF
;
CHAO, TS
;
電子工程學系及電子研究所
A method of using a thin oxide on the top of the poly-Si gate to getter fluorine for BF2+ in pMOS is proposed and demonstrated. Due to less amount of fluorine in the poly-Si as well as in the gate oxide, the boron penetration through the gate oxide is suppressed. The MOS capacitors fabricated by using this method show less shifts and distortion on C-V curves and better electrical characteristics.
FORMATION AND CHARACTERIZATION OF GAAS/AS SUPERLATTICE GROWN BY MOLECULAR-BEAM EPITAXY AT LOW SUBSTRATE-TEMPERATURE
(1995-05-01)
CHENG, TM
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CHANG, CY
;
HUANG, JH
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電控工程研究所
;
Institute of Electrical and Control Engineering
High-resolution X-ray diffractometer and transmission electron microscope (TEM) are used to characterize the redistribution of As precipitates in Si delta-doped GaAs grown by molecular beam epitaxy at low substrate temperature (230 degrees C). The superlattice satellite peaks are observed for samples annealed at 700-800 degrees C for 10 min, which is attributed to the formation of a GaAs/As superlattice during the annealing period. The degree of As precipitates confined on the delta-doped planes is revealed on the intensity of satellite peaks in the X-ray rocking curves, as confirmed by the TEM observations. The lattice expansion and contraction of the annealed low-temperature epitaxial layers can be easily observed from the asymmetry of the satellite peaks.