Browsing by Issue Date, starting with "2003-04-01"

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A novel soft-program for a narrow erased state Vt distribution, read disturbance suppression and over-program annihilation in multilevel cell flash memories
(2003-04-01)
Yeh, CC
;
Fan, TH
;
Lu, TC
;
Wang, TH
;
Pan, S
In floating gate flash memories, anode hot hole injection induced by the channel FN erase will result in tunnel oxide, degradation, severe read disturbance and an abnormally fast program. All of these issues are critical for multilevel cell (MLC) flash memory design, which requires precise threshold voltage placement, good data retentivity and programming controllability. In this paper, a novel soft-program scheme is proposed to narrow the threshold voltage distribution in the first level. Cycling-induced read disturbance and programming inaccuracy are also reduced. This technique is essential for the application of more-than-2-bit MLC, flash memories.
Novel vertical polysilicon thin-film transistor with excimer-laser annealing
(2003-04-01)
Lee, MZ
;
Lee, CL
;
Lei, TF
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
In this paper, we propose a novel self-alignment vertical thin-film transistor (VTFT) structure with excimer laser annealing (ELA). The ELA on source and drain decreases the process temperature, suppresses the lateral diffusion of dopants in short channel devices and increases the driving current. Furthermore, the VTFTs have high carrier mobility, compared to conventional polysilicon thin film transistors (TFTs).
A reliable procedure for testing linear regulators with one-sided specification limits based on multiple samples
(2003-04-01)
Pearn, WL
;
Lin, GH
;
工業工程與管理學系
;
Department of Industrial Engineering and Management
Process capability indices C-PU and C-PL are developed in the manufacturing industry to provide quantitative measures on process potential and performance. for processes with one-sided specification limits. Statistical properties of the estimators of C-PU and C-PL have been investigated extensively, but only restricted to cases with single samples. In this paper, we consider the estimation and capability testing of C-PU and C-PL based on multiple samples. We show that the proposed estimator of C-PU and C-PL are indeed the uniformly minimum variance unbiased estimators (UMVUEs). A simple procedure based on a hypothesis testing using the UMVUE is developed for the practitioners to use for judging whether a stable process meets the preset capability requirement. (C) 2002 Elsevier Science Ltd. All rights reserved.
Watermarking approach to embedded signature-based authentication by channel statistics
(2003-04-01)
Yang, ZF
;
Tsai, WH
;
資訊工程學系
;
Department of Computer Science
Embedded signature-based authentication is a highly promising watermarking method for solving high-level authentication problems. This work proposes such a watermarking approach using channel statistics evaluated from a reference watermark. The basic concept is to consider the problem to be an example of communications with side information, which is the reference watermark embedded in the host with the signature at the sender site. At the receiver site, the reference watermark is first extracted to determine channel statistics, which are used to generate information about signature reliability. Three kinds of information are derived, including a reliability measure, an entropy measure, and an authenticated signature. Experimental results establish that the measures of reliability and uncertainty are meaningful, and that the embedded signature can survive high-quality JPEG compression and manipulations such as negation, cropping, replacement, and modification. (C) 2003 Society of Photo-Optical Instrumentation Engineers.
Brownian dynamics simulations of the effects of hydrodynamic interactions on the polymer viscoelastic behavior
(2003-04-01)
Yang, DJ
;
Lin, YH
;
應用化學系
;
Department of Applied Chemistry
Brownian dynamics simulation is used to investigate the viscoelastic response of the Gaussian chain to a step shear deformation in both the linear and non-linear regions under the influence of hydrodynamic interactions. Both the preaveraged Oseen tensor and the Rotne-Prager tensor are used in the study. In the former case, the simulation results are shown to be in agreement with the expected results calculated using the eigenvalues of the normal modes of motion obtained numerically. It is shown that an initial state with zero second normal-stress difference is generated by the step shear deformation. The subsequent rise of the second normal-stress difference as revealed by the simulation is shown mainly arising from the coupling of the recoil of the stretched bond in the direction of deformation and the anisotropy in the hydrodynamic interaction created by the step deformation. (C) 2003 Elsevier Science Ltd. All rights reserved.
Thermal properties and hydrogen bonding in polymer blend of polybenzoxazine/poly(N-vinyl-2-pyrrolidone)
(2003-04-01)
Su, YC
;
Kuo, SW
;
Yei, DR
;
Xu, HY
;
Chang, FC
The thermal properties and hydrogen bonding behavior of B-a type polybenzoxazine (PBZZ)/PVP blends were investigated by DSC and FIFIR. The DSC result shows a single T-g over the entire compositions and a large positive deviation based on Kwei equation was observed in the T-g versus composition diagram, implying that strong hydrogen bonding interaction exists between PBZZ and PVP segments. The strength of hydrogen bonding interaction is in the order of inter-association between the hydroxyl group of PBZZ and the carbonyl group of PVP (K-A = 594 L mol(-1)) > self-association between the hydroxyl group of pure PBZZ (K-B = 72.6 L mol(-1)) > inter-association between the hydroxyl and the Mannich-based bridge of pure PBZZ (K-C < 10 L mol(-1)). Good correlation between DSC and FIFIR analysis were observed. (C) 2003 Elsevier Science Ltd. All rights reserved.
Device characteristics of polysilicon thin-film transistors fabricated by electroless plating Ni-induced crystallization of amorphous Si
(2003-04-01)
Chao, CW
;
Wu, YCS
;
Hu, GR
;
Feng, MS
;
材料科學與工程學系
Compared with conventional solid phase crystallized (SPC) thin-film transistors (TFTs), metal-induced laterally crystallized (MILL) TFTs exhibit significantly enhanced performance. Metal films are usually deposited by the physical vapor deposition (PVD) method, which is time-consuming and expensive in terms of equipment cost. In this work, a simpler electroless plating Ni was introduced to replace PVD Ni. It was found that the morphologies and the device characteristics of Ni-induced lateral crystallization TFT were as good as those of PVD Ni-induced lateral crystallization TFT.
A low-power design for Reed-Solomon decoders
(2003-04-01)
Chang, HC
;
Lee, CY
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
In this paper, a low-power design for the Reed-Solomon (RS) decoder is presented. Our approach includes a novel two-stage syndrome calculator that reduces the syndrome computations by one-half, a modified Berlekamp-Massey algorithm in the key equation solver and a terminated mechanism in the Chien search circuit. The test chip for (255,239) and (208,192) RS decoders are implemented by 0.25 mum CMOS 1P5M and 0.35 mum CMOS SPQM standard cells, respectively. Simulation results show our approach can work successfully and achieved large reduction of power consumption on the average.
A fuzzy data mining algorithm for finding sequential patterns
(2003-04-01)
Hu, YC
;
Chen, RS
;
Tzeng, GH
;
Shieh, JH
;
科技管理研究所
Since fuzzy knowledge representation can facilitate interaction between an expert system and its users, the effective construction of a fuzzy knowledge base is important. Fuzzy sequential patterns described by natural language are one type of fuzzy knowledge representation, and can thus be helpful in building a prototype fuzzy knowledge base. We define that a fuzzy sequence is an ordered fist of frequent fuzzy grids, and the length of a fuzzy sequence is the number of frequent fuzzy grids in the frequent fuzzy sequence. Frequent fuzzy grids and frequent fuzzy sequences can be determined by comparing individual fuzzy supports with the user-specified minimum fuzzy support. A fuzzy sequential pattern is just a frequent fuzzy sequence, but it is not contained in any other frequent fuzzy sequence. In this paper, an effective algorithm called the Fuzzy Grids Based Sequential Patterns Mining Algorithm (FGBSPMA) is proposed to generate fuzzy sequential patterns. A numerical example is used to show an analysis of the user visit to websites, demonstrating the usefulness of the proposed algorithm.
A unifying framework for intelligent DNS management
(2003-04-01)
Chen, CS
;
Tseng, SS
;
Liu, CL
;
資訊技術服務中心
;
Information Technology Services Center
The Domain Name System (DNS) is a special kind of distributed directory service for people to create and access the network information systems by (1) allowing local control of its segments and (2) making each segment's data available on the Internet using a client-server scheme. However, few administrators have the expertise to do the jobs well since this distributed mechanism is a double-edged sword; it allows DNS not only to scale to Internet size but also allows for incredible mis-configurations. The presented study is an analysis of what problems and difficulties most DNS administrators might encounter and provides the insights into how various DNS assistant sub-systems could be designed and deployed to solve the complex problems or alleviate these DNS administration job loadings. Ontologies become an important mechanism to build information systems. The role of ontologies is to capture domain knowledge and provide a commonly agreed upon understanding of a domain. The advantages include the sharing and re-use of knowledge, and the better engineering of knowledge-based systems with respect to acquisition, verification and maintenance. In this paper, we propose a unifying framework (e.g. including configuration, outstanding traffic monitoring and analysis, planning and management, tutoring, etc.) for supporting intelligent DNS management using web interface and expert system technology to help inexperienced administrators in insuring the smooth operation of their DNS systems. To help extract knowledge, we propose an efficient DNS Ontology Construction Algorithm to fast conceptualize DNS domain knowledge through a hybrid method of brainstorming and use cases modeling. While some sub-systems are still under development, others have been prototyped and deployed for everyday use. As our experience with a first simple prototype has shown, the paradigm of using DNS ontology to build a unifying framework for intelligent DNS management works good and effective. It is supposed that all these might become an integral part of the DNS administration activities of an organization in the near future. (C) 2003 Elsevier Science Ltd. All rights reserved.
Asymptotic behaviors in a transiently chaotic neural network
(2003-04-01)
Chen, SS
;
Shih, CW
;
應用數學系
;
Department of Applied Mathematics
We are interested in the asymptotic behaviors of a discrete-time neural network. This network admits transiently chaotic behaviors which provide global searching ability in solving combinatorial optimization problems. As the system evolves, the variables corresponding to temperature in the annealing process decrease, and the chaotic behaviors vanish. We shall find sufficient conditions under which evolutions for the system converge to a fixed point of the system. Attracting sets and uniqueness of fixed point for the system are also addressed. Moreover, we extend the theory to the neural networks with cycle-symmetric coupling weights and other output functions. An application of this annealing process in solving travelling salesman problems is illustrated.
Structure of mixed convective longitudinal vortex air flow driven by a heated circular plate embedded in the bottom of a horizontal flat duct
(2003-04-01)
Tuh, JL
;
Lin, TF
;
機械工程學系
;
Department of Mechanical Engineering
In this study experimental flow visualization combined with transient temperature measurement are conducted to investigate the structure of the buoyancy driven longitudinal vortex rolls in low Reynolds number mixed convective air flow through a horizontal flat duct with an isothermally heated circular disk embedded in the bottom plate of the duct for the Reynolds number ranging from 15.1 to 99.2 and Rayleigh number from 3506 to 29,493. How the circular geometry of the heated surface affects the longitudinal vortex flow characteristics is investigated in detail. The results indicate that the longitudinal vortex rolls (L-rolls) in the duct core are induced at more upstream locations than those near the duct sides, which is completely opposite to those induced in a duct with a uniformly heated bottom. Besides, the thermals driven by the circular heated surface are not evenly spaced in the spanwise direction and are slightly asymmetric. It is of interest to note that at a given Rayleigh number Ra the thermals are unstable at high Reynolds numbers, suggesting the existence of the inertia driven instability. Thus the L-rolls evolved from these thermals are also unstable with the presence of nonperiodic generation and disappearance of new L-rolls. But at slightly lower Re the thermals and L-rolls are steady and regular. The vortex flow becomes unstable and irregular for a further reduction in the Reynolds number, which obviously results from the buoyancy driven instability. The simultaneous presence of these two instability mechanisms explains the appearance of the reverse steady-unsteady transition in the vortex flow. Based on the present data, a flow regime map is given to delineate various L-roll patterns driven by the circular heated plate. In addition, the boundaries separating these patterns are empirically correlated. Empirical correlations for the onset points of the L-rolls are also provided. (C) 2002 Elsevier Science Ltd. All rights reserved.
A new method for measuring the chiral parameter and the average refractive index of a chiral liquid
(2003-04-01)
Lin, JY
;
Su, DC
;
光電工程學系
;
Department of Photonics
We designed a method for measuring chiral parameter and average refractive index of an isotropic chiral medium using critical angle phenomena. Linearly polarized light is guided to project onto the interface of a semi-spherical glass and a chiral liquid. The reflected light passes through an analyzer to extract the interference signal of s- and p-polarization lights. Their phase difference is first optimized by a suitable optical arrangement and subsequently measured by a heterodyne interferometer. The result, then, is fed into equations to estimate the chiral parameter. We determine the average index of refraction from the critical angle occurred at the discontinuity of the phase difference of two polarized lights. Our method of measurement has the implicational merits of both common-path interferometry and heterodyne interferometry. (C) 2003 Elsevier Science B.V. All rights reserved.
Distance-preserving mappings from binary vectors to permutations
(2003-04-01)
Chang, JC
;
Chen, RJ
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Klove, T
;
Tsai, SC
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資訊工程學系
Mappings of the set of binary vectors of a fixed length to the set of permutations of the same length are useful for the construction of permutation codes. In this correspondence, several explicit constructions of such mappings preserving or increasing the Hamming distance are given. Some applications are given to illustrate the usefulness (if the construction. In particular, a new lower bound on the maximal size of permutation arrays (PAs) is given.
A periodic microstrip radial antenna array with a conical beam
(2003-04-01)
Chen, KC
;
Qian, YX
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Tzuang, CKC
;
Itoh, T
;
電信工程研究所
The analysis and design of a microstrip antenna array with a conical beam are presented. The antenna array employs a periodic structure derived from the microstrip on a perforated ground plane. The microstrip antenna array consists of eight leaky lines evenly distributed around a circle. Each line radiates mainly a pair of forward and backward beams, forming a conical beam. The new leaky line design employs the concept of space-harmonic modulation on the EH0 mode launched at the common joint of the antenna array. The scattering and dispersion characteristics of the leaky line are thoroughly investigated. The fact that the perturbation of the antisymmetric holes made by photolithographic etching excites the leaky EH1 mode is theoretically and experimentally validated. Scattering analyses of the surface currents on the microstrip, however, reveal in detail the physical operation of the leaky line. The dispersion characteristics are, thus, established and shown in a Brillouin diagram, indicating the role of each space harmonic, denoted by its complex propagation constant gamma(m,n)(+/-). gamma(m,n)(+/-) represents a traveling-wave component of the nth higher-order spatial component in association with the EHm mode: the superscript, + signifies a forward (backward) traveling wave. For the particular leaky line design, gamma(0)(+),(-1) and gamma(1,0)(+) space barmonics, both showing odd-symmetric field polarization, and both outside the triangular Brillouin region, form the backward and forward leaky waves, respectively. When the leaky lines are evenly and collinearly tied, an 11.5-GHz radial antenna array prototype is formed, and emits a conical beam, showing a 3-dB beamwidth of 24degrees at the flare angle of 31degrees.
AgentGateway: A communication tool for multi-agent systems
(2003-04-01)
Chen, JJY
;
Su, SW
;
資訊工程學系
;
Department of Computer Science
With the rapid growth of multi-agent systems (MAS), there is a pressing need to communicate between different MAS. Various MAS communication standards have been proposed. However, MAS is usually designed to meet special need, thus making it difficult to follow a standard. This paper presents a tool called AgentGateway trying to solve this problem using a simple, effective approach. The tool translates messages from one MAS to intermediate XML-based messages, which then are translated to messages for another MAS. AgentGateway is scalable, meaning that new MAS can easily join it. Furthermore, it provides transparent and reliable communication. A prototype is developed that shows communication between two MAS, namely, Java Agent Template Lite (JATLite) and OAA, can be done using this approach. (C) 2002 Elsevier Science Inc. All rights reserved.
Rendering complex scenes using spatial subdivision and textured LOD meshes
(2003-04-01)
Chen, CC
;
Chuang, JH
;
Lee, BY
;
Feng, WW
;
Chiou, T
We present a hybrid rendering scheme that explores the locality of visibility at the cost of extra storage and prefetching, and makes a tradeoff between image quality and rendering efficiency by using textured level-of-detail (LOD) meshes. The space is first subdivided into cells. For each cell, inside objects are rendered as normal while outside objects are rendered as textured LOD meshes using projective texture mapping. The textured LOD meshes are object based and derived from the original meshes based on the captured depth images viewed at the centers of the cell and its adjacent cells. With such a textured LOD mesh, problems commonly found in image-based rendering, such as the hole problem due to occlusion among objects and the gap problems due to resolution mismatch, can be avoided. The size of holes due to self-occlusion is constrained to be within a user-specified tolerance. Several scenes with millions of polygons have been tested and higher than 200 FPS has been achieved with a little loss of image quality. (C) 2003 Elsevier Science Ltd. All rights reserved.
Adaptive fuzzy sliding mode controller for linear systems with mismatched time-varying uncertainties
(2003-04-01)
Tao, CW
;
Chan, ML
;
Lee, TT
;
電控工程研究所
;
Institute of Electrical and Control Engineering
A new design approach of an adaptive fuzzy sliding mode controller (AFSMC) for linear systems with mismatched time-varying uncertainties is presented in this paper. The coefficient matrix of the sliding function can be designed to satisfy a sliding coefficient matching condition provided time-varying uncertainties are bounded. With the sliding coefficient matching condition satisfied, an AFSMC. is proposed to stabilize the uncertain system. The parameters of the output fuzzy sets in the fuzzy mechanism are on-line adapted to improve the performance of the fuzzy sliding mode control system. The bounds of the uncertainties are not required to be known in advance for the presented AFSMC. The stability of the fuzzy control system is guaranteed and the system is shown to be invariant on the sliding surface. Moreover, the chattering around the sliding surface in the sliding mode control can be reduced by the proposed design. approach. Simulation results are included to,illustrate the effectiveness of the proposed AFSMC.
Geometric variations and magnetic field effects on electron energy states of InAs/GaAs quantum rings
(2003-04-01)
Li, YM
;
Lu, HM
;
友訊交大聯合研發中心
;
D Link NCTU Joint Res Ctr
We study electron energy states in three-dimensional (313) narrow-gap semiconductor quantum rings with ellipsoidal-shape torus (EST) and cut-bottom EST (CBEST) under an applied magnetic field. Our model includes the effective one-electronic-band Hamiltonian, the energy- and position-dependent electron effective mass approximation, and the Ben Daniel-Duke boundary condition. It is solved by the nonlinear iterative method to obtain a "self-consistent" solution numerically. The electron energy dependence on the inner radius, height, and lateral width is investigated for InAs/GaAs quantum rings with EST and CBE T shapes. The height and lateral width play a crucial role in varying the energy spectra of the rings. When the magnetic field is applied on a fixed-size CBEST ring, we find that there is a nonperiodical transition among the lowest electron energy states. Compared with the well-known ID Aharonov-Bohm periodical oscillation, the electron energy levels increase and oscillate nonperiodically when the magnetic field is increased. Our calculation for single-electron magnetization shows that the magnetization is nonperiodical and is a negative function of magnetic field.
Optimization of the anti-punch-through implant for electrostatic discharge protection circuit design
(2003-04-01)
Li, YM
;
Lee, JW
;
Sze, SM
;
電子工程學系及電子研究所
;
友訊交大聯合研發中心
In this study, an optimal anti-punch-through implant for electrostatic discharge (ESD) protection devices is investigated. By solving a two-dimensional (2D) hydrodynamic (HD) device model as well as a lattice temperature equation numerically, the current density, carrier temperature, and parasitic capacitance of four different device structures are analyzed and compared for suppressing short-channel effects, reducing device heating, and improving ESD robustness simultaneously. The structure difference among these four devices is the location of anti-punch-through implantation; that is: (a) the Type 1 device is the control device without anti-punch-through implantation; (b) the Type 2 device is the device with anti-punch-through implantation under the source/drain extension; (c) the Type 3 device, with anti-punch-through implantation under the deep source/drain junction; and (d) the Type 4 device, with anti-punch-through implantation surrounding all junctions. By comparing these four device structures, we find that the Type 4 device not only has a lower electron temperature (and hence good thermal immunity) but also has a larger current density under an applied high bias. Therefore, this device maintains a higher driving capacity without producing a higher amount of heat and is suitable for the ESD protection device application.