Browsing by Author "Chiu, CC"

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A discriminant analysis based recursive automatic thresholding approach for image segmentation
(2005-07-01)
Wu, BF
;
Chen, YL
;
Chiu, CC
;
電控工程研究所
;
Institute of Electrical and Control Engineering
In this study, we have proposed an efficient automatic multilevel thresholding method for image segmentation. An effective criterion for measuring the separability of the homogenous objects in the image, based on discriminant analysis, has been introduced to automatically determine the number of thresholding levels to be performed. Then, by applying this discriminant criterion, the object regions with homogeneous illuminations in the image can be recursively and automatically thresholded into separate segmented images. The proposed method is fast and effective in analyzing and thresholding the histogram of the image. In order to conduct an equitable comparative performance evaluation of the proposed method with other thresholding methods, a combinatorial scheme is also introduced to properly reduce the computational complexity of performing multilevel thresholding. The experimental results demonstrated that the proposed method is feasible and computationally efficient in automatic multilevel thresholding for image segmentation.
A fast algorithm for reliability-oriented task assignment in a distributed system
(2002-11-01)
Chiu, CC
;
Yeh, YS
;
Chou, JS
;
資訊科學與工程研究所
;
Institute of Computer Science and Engineering
Distributed systems (DS) have become a major trend in computer systems design today because of their high speed and high reliability. Reliability is an important performance parameter in DS design. The distribution of programs and data files can affect the system reliability. Usually, designers add redundant copies of software and/or hardware to increase the system's reliability. The reliability-oriented task assignment problem, which is NP-hard, is to find a task distribution such that the program reliability or system reliability is maximized. In this paper, we developed a reliability-oriented task allocation scheme, based on a heuristic algorithm, for DS to find an approximate solution. The simulation shows that, in most test cases with one copy, the algorithm finds suboptimal solutions efficiently. When the algorithm cannot obtain an optimal solution, the deviation is very small; therefore, this is a desirable approach for solving these problems. (C) 2002 Elsevier Science B.V. All rights reserved.
A genetic algorithm for reliability-oriented task assignment with (k)over-tilde-$ duplications in distributed systems
(2006-03-01)
Chiu, CC
;
Hsu, CH
;
Yeh, YS
;
資訊科學與工程研究所
;
Institute of Computer Science and Engineering
A distributed system is a collection of processor-memory pairs connected by communication links. The reliability of a distributed system can be expressed using the distributed program reliability, and distributed system reliability analysis. The computing reliability of a distributed system is an NP-hard problem. The distribution of programs & data-files can affect the system reliability. The reliability-oriented task assignment problem, which is NP-hard, is to find a task distribution such that the program reliability or system reliability is maximized. For example, efficient allocation of channels to the different cells can greatly improve the overall network throughput, in terms of the number of calls successfully supported. This paper presents a genetic algorithm-based reliability-oriented task assignment methodology (GAROTA) for computing the (k) over tilde -DTA reliability problem. The proposed algorithm uses a genetic algorithm to select a program & file assignment set that is maximal, or nearly maximal, with respect to system reliability. Our numerical results show that the proposed algorithm may obtain the exact solution in most cases, and the computation time seems to be significantly shorter than that needed for the exhaustive method. When the proposed method fails to give an exact solution, the deviation from the exact solution is very small. The technique presented in this paper would be helpful for readers to understand the correlation between task assignment reliability, and distributed system topology.
A real-time robust lane detection approach for autonomous vehicle environment
(2004)
Wu, BF
;
Chen, CJ
;
Chiu, CC
;
Lai, TC
;
電控工程研究所
This paper proposes a real-time lane detection algorithm which provides adaptive region of interesting to reduce computational load and is robust for real road environment, e.g., road inclination, road width calibration. Compared to previous approaches, the flat road assumption is released in our approach so that the result is more close to real road environment. This work has been successfully verified on highway and urban with different velocities 110 km/h and 50 km/h, respectively, in the real vehicle, TAIWAN iTS-1, which is an experimental car of Taiwan ITS project. The algorithm is also demonstrated on the lanes which are with shadows, texts, crooks, or sheltered by other vehicles for sunny and night environment.(1)
A reversing traversal algorithm to predict deleting node for the optimal k-node set reliability with capacity constraint of distributed systems
(2001-02-15)
Yeh, YS
;
Chiu, CC
;
資訊科學與工程研究所
;
Institute of Computer Science and Engineering
A k-node set reliability with capacity constraint is defined as the probability that a set, K, of nodes is connected in a distributed system and the total capacity of the nodes in K is sufficient under a given capacity. This is generally an NP-hard problem. For reducing computational time, a reasonable k-node set within a given capacity constraint must be determined by an efficient algorithm. In this work, we propose a reversing traversal method to derive a k-node set under capacity constraint having an approximate solution. Initially, the set K is assigned to all the nodes in a system. The proposed algorithm uses an objective function to evaluate the fitness value of each node in K and predict a deleting node, which is not a critical node, in K with minimal fitness value. After deleting the node, the fitness value of each node that is adjacent to the deleted node is tuned. The above two processes are repeated until the total capacity of the nodes in each subset of the set K does not satisfy the capacity constraint. In our simulation, the proposed method can obtain an exact solution above 90%. When a sub-optimal solution is obtained, the average deviation from an exact solution is under 0.0033. Computational results demonstrate that the proposed algorithm is efficient in execution time and effective for obtaining an optimal k-node set with capacity constraint. (C) 2001 Elsevier Science B.V. All rights reserved.
Algorithms for compressing compound document images with large text/background overlap
(2004-12-01)
Wu, BF
;
Chiu, CC
;
Chen, YL
;
電控工程研究所
;
Institute of Electrical and Control Engineering
Two algorithms are presented for compressing image documents, with a high compression ratio for both colour and monochromatic compound document images. The proposed algorithms apply a new method of segmentation to separate the text from the image in a compound document in which the text overlaps the background. The segmentation method classifies document images into three planes: the text plane, the background (non-text) plane and the text's colour plane, each of which are processed using different compression techniques. The text plane is compressed using the pattern matching technique, called JB2. Wavelet transform and zerotree coding are used to compress the background plane and the text's colour plane. Assigning bits for different planes yields high-quality compound document images with both a high compression ratio and well presented text. The proposed algorithms greatly outperform two well known image compression methods, JPEG and DjVu, and enable the effective extraction of the text from a complex background, achieving a high compression ratio for compound document images.
An explicit model for a quantum channel in 2DEG
(2002-05-01)
Fedirko, VA
;
Chen, MH
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Chiu, CC
;
Chen, SF
;
Wu, KH
A two-parametric model for a channel in a two-dimensional electron gas (2DEG) is proposed which allows for the explicit analytical solution for the problem of quantum electron transport through the constriction. Conductance step smearing appears naturally and a simple criterion for the step occurrence in terms of channel parameters is given. (C) 2002 Elsevier Science Ltd. All rights reserved.
An intelligent vision-based real-time integration system on autonomous vehicles
(2004)
Wu, BF
;
Chiu, CC
;
Chen, CJ
;
Wu, WC
;
Perng, JW
In this paper, an intelligent real-time system on autonomous vehicles is presented. A wireless-based remote control scheme is developed. A vision-based obstacle detection system and a radar sensor are integrated into the on-vehicle controller to automatically brake the vehicle under emergency. Finally, a successfully on-road demonstration is also completed with our experimental car. TAIWAN iTS-1.(1)
Anisotropic photoexcited carrier dynamics in (100)-, (001)-, and (110)-oriented YBCO films by polarized ultrafast optical spectroscopy
(2003-06-01)
Luo, CW
;
Chen, MH
;
Chiu, CC
;
Chen, SP
;
Wu, KH
We report the time-resolved ultrafast optical spectroscopy results obtained from a series of well characterized (001)-, (100)- and (110)-oriented YBa2Cu3O7-delta (YBCO) superconducting films prepared by pulsed laser deposition. The well-controlled film orientation has allowed us to probe the relaxation dynamics along various crystal orientations using respectively polarized pump and probe laser beams. The significant anisotropies in both the magnitude of the characteristic relaxation time and the temperature dependence of the photo-induced transient reflectance change indicate the nature of relaxation channel might be intrinsically different along different orientations. The implications of the results on the fundamental characteristics concerning superconducting gaps are discussed.
Complex document image segmentation using localized histogram analysis with multi-layer matching and clustering
(2004)
Chen, YL
;
Chiu, CC
;
Wu, BF
;
電控工程研究所
;
Institute of Electrical and Control Engineering
This paper proposes a new segmentation method to separate the text from various complex document images. An automatic multilevel thresholding method, based on discriminant analysis, is utilized to recursively segment a specified block region into several layered image sub-blocks. Then the multi-layer region-based clustering method is performed to process the layered image sub-blocks to form several object layers. Hence character strings with different illuminations, non-text objects and background components are segmented into separate object layers. After performed text extraction process, the text objects with different sizes, styles and illuminations are properly extracted. Experimental results on the extraction of text strings from complex document images demonstrate the effectiveness of the proposed region-based segmentation method.
Design of vocabulary-independent Mandarin keyword spotters
(2000-07-01)
Liu, CM
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Chiu, CC
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Chang, HY
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資訊工程學系
;
Department of Computer Science
This paper considers the design of a vocabulary-independent keyword spotter for Mandarin speech according to the framework by Huang et al. [1]. This paper considers three varieties of filler model structures for the framework based on subsyllabic grammar of Mandarin speech. On the basis of the three structures, we infer the problems of this framework through three arguments and presents two methods to modify the spotting vehicle.
Differences in curing behavior of cocured and IPN materials
(2001-05-16)
Lin, MS
;
Chiu, CC
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應用化學系
;
Department of Applied Chemistry
This study addressed the blending and cocuring of resole and epoxy, using NaOH and 4,4'-diaminodiphenylmethane as curing agents. IR band shifts regarding the molecular interactions were investigated with FTIR. Exothermic peak shifts during cocuring reactions were studied with dynamic DSC. Viscosity increases were measured with a Brookfield LVT viscometer at 100 degreesC. The dynamic mechanical properties of the cocured samples were investigated using rheometric dynamic spectroscopy (RDS). Experimental results revealed that the molecular interactions between resole and epoxy resulted in good compatibility as shown by the single damping peak in the RDS curve and the single glass transition for each cocured sample. Also apparent were accelerated curing rates, leading to shifts of the exothermic peaks to lower temperature and faster viscosity increases. Nevertheless, enhanced gel fractions and increased glass-transition temperatures (T-g) of the samples were generally observed for this cocured system. The average molecular weight between crosslinked points calculated for the cocured materials also showed much less than the two components. These curing behaviors were quite different from those of the Interpenetrating Polymer Network (IPN) materials, which usually indicated lowered gel fractions, decreased T-g, and higher average molecular weight between crosslinkings than for components. (C) 2001 John Wiley & Sons, Inc.
Microstructural investigation of oxidized Ni/Au ohmic contact to p-type GaN
(1999-01-01)
Chen, LC
;
Chen, FR
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Kai, JJ
;
Chang, L
;
Ho, JK
The phase evolution of oxidized (10nm) Ni/(5nm) Au films on p-GaN was examined with a field emission gun transmission electron microscope in conjunction with composition analyses to explore the mechanism of formation of low resistance ohmic contact to p-GaN. The p-GaN/Ni/Au sample heat treated above 500 degreesC in air was mainly composed of a mixture of crystalline NiO, Au and amorphous Ni-Ga-O phases. Small voids adjacent to the p-GaN film were also found. Moreover, NiO partially contacts to p-GaN as well as Au islands and the amorphous Ni-Ga-O phases. The results suggest that the crystalline NiO and/or amorphous Ni-Ga-O phases may play a significant role in the formation of a low resistance ohmic contact to p-GaN.
Microstructural investigation of oxidized Ni/Au ohmic contact to p-type GaN
(1999)
Chen, LC
;
Chen, FR
;
Kai, JJ
;
Chang, L
;
Ho, JK
The microstructure of oxidized Ni/Au films on p-GaN was examined to elucidate the formation of a low resistance ohmic contact to p-GaN with a field-emission gun transmission electron microscope in conjunction with composition analyses. The p-GaN/Ni/Au samples were heat treated at 500 degrees C in air mainly composed of a mixture of crystalline NiO, Au, and amorphous Ni-Ga-O phases. Small voids adjacent to the p-GaN film were also observed. The as-deposited Au film converted into discontinuous islands containing small amounts of Ni that connect with p-GaN. NiO formed a continuous film at the surface that covers the Au islands and the amorphous Ni-Ga-O phases. Moreover, NiO partially contacts p-GaN as well as Au islands and the amorphous Ni-Ga-O phase. The orientation relationship of the crystalline NiO, Au-rich islands, and p-GaN film was identified as NiO(111)//Au(11 (1) over bar)//GaN(0002) and NiO[1 (1) over bar 0]//Au[1 (1) over bar 0]//GaN[11 (2) over bar 0]. The results suggested that Ni atoms diffuse through the Au layer onto the surface and react with oxygen to form NiO, whereas Au atoms diffuse towards the inside to form a Au-Ni alloy. The microstructural examination indicated that the crystalline NiO and/or the amorphous Ni-Ga-O phases may significantly affect the low resistance ohmic contact to p-GaN. (C) 1999 American Institute of Physics. [S0021-8979(99)05219-6].
Multi-layer segmentation of complex document images
(2005-12-01)
Wu, BF
;
Chen, YL
;
Chiu, CC
;
電控工程研究所
;
Institute of Electrical and Control Engineering
Text is commonly printed on a complex background. Segmenting text is an important part in document analysis. In the past some methods have been shown for the segmentation of texts with images. However, previous studies have not sufficiently addressed complex compound documents. This investigation presents an algorithm for the segmentation of text in various document images. The proposed segmentation algorithm applies a new multilayer segmentation method to separate the text from various compound document images, independent from the text and background overlapping or not. This method solves various problems associated with the complexity of background images. Experimental results obtained using various document images scanned from book covers, advertisements, brochures and magazines, reveal that the proposed algorithm can successfully segment Chinese and English text strings from various backgrounds, regardless of whether the texts are over a simple, slowly varying or rapidly varying background texture.
Multi-layers segmentation method for complex document images
(2003)
Wu, BF
;
Chen, YL
;
Chiu, CC
;
電控工程研究所
;
Institute of Electrical and Control Engineering
The proposed segmentation algorithm uses a new multi-layers segmentation method to separate the text from various compound document images, no matter whether the text and background overlap or not. This approach overcomes various issues that arise due to the complexity of its background. Experimental results with different document images scanned from advertisements, brochures, and magazines show that the proposed algorithm can successfully segment Chinese and English text strings from various backgrounds, no matter the text overlap a simple, slowly or highly varying background.
Parameter design optimization via neural network and genetic algorithm
(2000-09-01)
Su, CT
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Chiu, CC
;
Chang, HH
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工業工程與管理學系
;
Department of Industrial Engineering and Management
Among the many extensive industrial applications which parameter design optimization problems have found include product development, process design and operational condition settings. The parameter design optimization problems are complex owing to that nonlinear relationships and interactions may occur among parameters. To resolve such problems, engineers commonly employ the Taguchi method. However, the Taguchi method has some limitations in practice. Therefore, in this work, we present a novel means of improving the effectiveness of the optimization of parameter design. The proposed approach employs the neural network and generic algorithm, and consists of two phases. Phase 1 formulates a fitness function for a problem by a neural network method to predict the value of the response for a given parameter setting. Phase 2 applies a genetic algorithm to search for the optimal parameter combination. A numerical example demonstrates the effectiveness of the proposed approach. Significance: This work provides an efficient approach to optimize the parameter design problems, which is relatively simple and is fairly easy for engineers to apply to diverse industrial applications.
Protection of epoxy resin against thermo-oxidation via co-curing epoxy/resole (I)
(2000)
Lin, MS
;
Chiu, CC
;
應用化學系
;
Department of Applied Chemistry
Co-cured materials based on 100/0, 50/50 and 0/100 weight ratios of resole/epoxy were prepared by using NaOH and 4,4'-diaminodiphenylmethane (MDA) as curing agents. Samples were spin-coated on Al plates and were subjected to accelerated aging at 150 degrees C in air for 49 days. The functional group changes during thermal oxidation were monitored with FT-IR at various times. Difference spectra were obtained by using aromatic absorption at 1608 cm(-1) as internal standard. Kinetic study was performed, and a first order of degradation was demonstrated. Experimental results revealed that the degradation rate constants for pure epoxy, 50/50 of resole/epoxy and pure resole are 9.32x10(-3), 4.29x10(-3) and 2.03x10(-3) h(-1), respectively, indicating a significant protection of epoxy against thermal oxidation via co-curing resole/epoxy. (C) 2000 Elsevier Science Ltd. All rights reserved.
Protection of epoxy resin against thermo-oxidation via cocuring epoxy/resole (II)
(2001)
Lin, MS
;
Chiu, CC
;
應用化學系
;
Department of Applied Chemistry
Cocured materials based on resole/epoxy in weight ratios of 100/0, 50/50 and 0/100 were prepared by using NaOH and 4,4'-diaminodiphenylmethane (DMA) as curing agents. These cocured samples were subjected to accelerated aging at 150 degreesC in air for 45 days. Continuous increase of carbonyl IR absorption at 1700-1740 cm(-1) indicated thermal oxidation. The sample with resole/epoxy = 50/50 showed significantly retarded formation of carbonyls. Mechanical property tests of samples during the course of aging, including tensile stress-strain, modulus, and impact resistance confirmed a significant protection of epoxy by incoporating resole into the epoxy via cocuring. (C) 2001 Elsevier Science Ltd. All rights reserved.
Reduction of the total execution time to achieve the optimal k-node reliability of distributed computing systems using a novel heuristic algorithm
(2000-01-01)
Chiu, CC
;
Yeh, YS
;
Chen, RS
;
資訊科學與工程研究所
;
Institute of Computer Science and Engineering
A distributed computing system is a collection of processor-memory pairs connected by communication links. A k-node set is a subset of total nodes in a distributed computing system. A k-node set with capacity constraint is a k-node set that possesses sufficient node capacity. Because computing the reliability of a distributed computing system is generally an NP-hard problem, an adequate k-node set with a given capacity constraint must be determined by an effective algorithm with an approximate reliability. Relatively few investigations, namely an exact method and a k-tree reduction method, have examined k-node reliability optimization with capacity constraint. Such investigations either spent an exponential time or rarely obtained an optimal solution. Therefore, in this work, we present a novel heuristic algorithm to reduce the computational time and deviation from an exact solution. The proposed algorithm has simple independent steps, including selection of k-node sets according to a node's weight or a link's weight. The number of selected k-node sets is either one or two, thereby spending less time to compute the reliability of k-node sets. Computational results demonstrate that the proposed algorithm is more effective and provides a better solution for a large distributed computing system than those in previous investigations. (C) 2000 Elsevier Science B.V. All rights reserved.