Browsing by Author "Chen, YJ"

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An educational water quality management game
(1996)
Kao, JJ
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Chen, YJ
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交大名義發表
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環境工程研究所
;
National Chiao Tung University
An educational game for water quality management is developed to assist a novice engineer or student to learn the compromises among three major objectives to manage water quality: cost, water quality, and equity. A window-based interface is developed on a microcomputer. A hypothetical example with four dischargers is used in the program, and the initial scenario is based on a uniform treatment scheme. The player acts as the manager of a water quality authority to design the best compromise policy. The friendly interfaces allows one to exercise judgment in selecting and in modifying discharge permit programs. The design and development of the game and related computer program are described. Network accessibility has provided a novel environment for remote education. A prototypical multimedia network interface is provided for local or foreign remote access to the game. Copyright (C) 1996 IAWQ.
An efficient scheme of general weighted fair allocation for enhanced best-effort service in high speed networks
(2001-03-01)
Chen, YJ
;
Lee, SY
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資訊工程學系
;
Department of Computer Science
This research is focused on enhanced best-effort service, which provides the minimum bandwidth guarantee and distributes the available bandwidth fairly to packet flows in a high speed network. These goals can be reached when the bandwidth allocation is general weighted (GW) fair among the flows. GW fairness ensures the minimum rate for every flow and, furthermore, allocates the excess bandwidth (the available bandwidth minus the sum of the minimum rates) to the flows in a way that is proportional to their weights. In the proposed scheme, switches coordinate to efficiently achieve GW fair allocation. In the process of achieving fairness, a switch not only takes O(log N) time for bandwidth allocation among N active flows when receiving feedback from its neighbor node, but also keeps the packet queue length below a target threshold. As a result, better performance in terms of end-to-end delay, packet loss ratio, and throughput can be achieved. A proof to show that the scheme can achieve GW fair allocation is presented. Finally, simulation results illustrate and suggest a good and justifiable system design.
An endurance evaluation method for flash EEPROM
(2004-05-01)
Zous, NK
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Chen, YJ
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Chin, CY
;
Tsai, WJ
;
Lu, TC
Trap generation is hard to estimate in a Flash cell due to a dynamic stress field during program and erase. In this paper, a linear correlation is found between the erase state V-T rollup, and cycling V-T window. With the knowledge of the time dependence of erase stress field based on Fowler-Nordheim (FN) tunneling, the V-T rollup during cycling is evaluated by incorporating field dependent oxide trap generation. The extracted Delta V-T degradation slope during constant FN stress can be applied quantitatively to predict the V-T window closure during Flash cell cycling.
Bounded tag fair queueing for broadband packet switching networks
(2000-01-01)
Chen, YJ
;
Lee, SY
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資訊工程學系
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Department of Computer Science
Fair Queueing (FQ) is an attractive packet scheduling mechanism, which can establish firewall among packet flows. Thus, the quality of service (QoS) of each flow can be guaranteed. To implement the mechanism, three important performance issues are concerned: fairness, bounded delay, and efficiency. We propose a scheme, named BTFQ, which satisfies the three criteria. The scheme BTFQ + is also proposed to improve the fairness property of BTFQ and is designed to combine with a low-cost, high-speed hardware for reducing computation time. For comparison, we classify some well-known packet scheduling schemes into six classes according to their fairness properties. BTFQ and BTFQ + are excellent in bounded delay and efficiency. Their fairness properties, although a little bit weak, are but still very good if the traffic load is under 95%, according to the simulation results. Because of the tradeoff among the performance issues, BTFQ and BTFQ + provide another good choices. (C) 2000 Elsevier Science B.V. All rights reserved.
Design and implementation of ultra-low latency optical label switching for packet-switched WDM networks
(2000-12-01)
Meagher, B
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Chang, GK
;
Ellinas, G
;
Lin, YM
;
Xin, W
An ultra-low latency, high throughput internet protocol(IP) over wavelength division multiplexing (WDM) packet switching technology for next-generation internet (NGI) applications has been designed and demonstrated. This method overcomes limitations of conventional optical packet switching, which require buffering of packets and synchronization of bits, rind optical burst switching methods that require estimation of delays at each node and for each path. An optical label switching technique was developed to realize flexible bandwidth-on-demand packet transport on a reconfigurable WDM network. The aim was to design a network with simplified protocol stacks, scalability, and data transparency, This network will enable the NGI users to send their data applications at gigabit/second access speed with low and predictable latency (<1 sec per switch node), with a system capacity of beyond multi-Tb/s. Packet forwarding utilizes WDM optical headers that are carried in-band on the same wavelength and modulated out-of-hand in the frequency domain.
Different approaches for reliability enhancement of p-channel flash memory
(2004)
Chung, SS
;
Chen, YJ
;
Tsai, AW
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電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
In this paper, we will demonstrate two different strategies for designing p-channel flash memories, for achieving better reliability, in particular data retention and drain-disturb. The first one is by using a gate-engineering approach and the other one is using a newly developed substrate bias enhanced Avalanche Hot Electron (ABE) injection programming scheme. For the former, a p-doped floating gate on both p-channel flash cells can be achieved with superior data retention characteristics as well as a 3-order improvement of the drain disturb. For the latter, it exhibits much higher speed and much lower voltage for programming, and very good drain disturb characteristics.
EEG-based drowsiness estimation for safety driving using independent component analysis
(2005-12-01)
Lin, CT
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Wu, RC
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Liang, SF
;
Chao, WH
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Chen, YJ
Preventing accidents caused by drowsiness has become a major focus of active safety driving in recent years. It requires an optimal technique to continuously detect drivers' cognitive state related to abilities in perception, recognition, and vehicle control in (near-) real-time. The major challenges in developing such a system include: 1) the lack of significant index for detecting drowsiness and 2) complicated and pervasive noise interferences in a realistic and dynamic driving environment. In this paper, we develop a drowsiness-estimation system based on electroencephalogram (EEG) by combining independent component analysis (ICA), power-spectrum analysis, correlation evaluations, and linear regression model to estimate a driver's cognitive state when he/she drives a car in a virtual reality (VR)-based dynamic simulator. The driving error is defined as deviations between the center of the vehicle and the center of the cruising lane in the lane-keeping driving task. Experimental results demonstrate the feasibility of quantitatively estimating drowsiness level using ICA-based multistream EEG spectra. The proposed ICA-based method applied to power spectrum of ICA components can successfully (1) remove most of EEG artifacts, (2) suggest an optimal montage to place EEG electrodes, and estimate the driver's drowsiness fluctuation indexed by the driving performance measure. Finally, we present a benchmark study in which the accuracy of ICA-component-based alertness estimates compares favorably to scalp-EEG based.
Existence of strong solutions to some quasilinear elliptic problems on bounded smooth domains
(2002-06-01)
Kuo, TH
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Chen, YJ
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應用數學系
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Department of Applied Mathematics
We consider the following quasilinear elliptic problems in a bounded smooth domain Z of R-N, N greater than or equal to 3: Lu = Sigma(i,j=1)(N) a(ij)(x,u) delta(2)u/deltax(i)deltax(j) + Sigma(i=1)(N)b(i)(x,u)deltau/deltax(i) + c(x, u)u = f (x) in Z, u = 0 on deltaZ, where f (x) is an element of L-p(Z) and all the coefficients a(ij), b(i), c are Carathedory functions. Suppose that a(ij) is an element of C-0,C-1((Z) over bar x R), a(ij), deltaa(ij)/deltax(i), deltaa(ij)/deltar, b(i), c is an element of L-infinity(Z x R), c less than or equal to 0 for i, j = 1,...N and the oscillations of a(ij) = a(ij)(x,r) with respect to r are sufficiently small. A global estimate for a solution u is an element ofW(2,p)(Z) boolean AND W-0(1,p)(Z) is established and the existence of a strong solution u is an element of W-2,W-p(Z) boolean AND W-0(1,p)(Z) is proved for p > N. Furthermore, we replace f(x) by f(x,r,xi) which is defined on Z x R x R-N and is a Carathedory function. Assume that [f(x, r, xi)] less than or equal to C-0 + h([r])[xi]theta, 0 less than or equal to theta < 2, where C-0 is a nonnegative constant, h([r]) is a locally bounded function, and -c greater than or equal to alpha(0) > 0 for some constant alpha(0). We prove the existence of solution u is an element of W-2,W-p(Z) boolean AND W-0(1,p)(Z) for the equation Lu = f (x, u, delu).
N incorporation into InGaAs cap layer in InAs self-assembled quantum dots
(2005-12-01)
Chen, JF
;
Hsiao, RS
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Hsieh, PC
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Chen, YJ
;
Chen, YP
This study presents the results of incorporating N into self-assembled InAs quantum dots (QDs) capped with an InGaAs cap layer. Experimental results indicate that such incorporation can redshift the QD ground state and decrease the energy spacing between the QD ground and first excited states. However, this incorporation reduces the potential barrier of the cap layer, increasing the electron escape from the QDs. Capacitance-voltage profiling shows that a broad shoulder corresponding to the electron emission from the QD ground to first-excited state cannot be resolved from the peak related to the electron emission from the excited states upon this incorporation. This finding implies that this incorporation reduces the energy spacing between the QD ground and first-excited states in the conduction band, thus correlating well with the photoluminescence data. In contrast, incorporating N directly into the InAs QD produces no redshift of the emission wavelength but introduces a deep trap at similar to 0.21 eV that depletes the electrons in the QDs. (c) 2005 American Institute of Physics.
Nanoprobe-based affinity mass spectrometry for selected protein profiling in human plasma
(2005-09-15)
Chou, PH
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Chen, SH
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Liao, HK
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Lin, PC
;
Her, GR
In recent decades, magnetic nanoparticles have emerged as a promising new platform in biomedical applications, particularly bioseparations. We have developed an immunoassay using antibody-conjugated magnetic nanoparticles as an efficient affinity probe to simultaneously preconcentrate and isolate targeted antigens from biological media. We combined this probe with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI MS) to profile proteins in diluted human plasma. The nanoparticles were designed to detect several disease-associated proteins and could be used directly in MALDI MS without an elution step, thereby facilitating multiple antigen screening and the characterization of antigen variants. Plasma antigens bound rapidly (similar to 10 min) to the antibody-conjugated nanoparticles, allowing the assay to be performed within 20 min. With sensitivity of detection in the femtomole range, the nanoscale immunoassay is superior to assays using microscale particles. We applied our method to comparative protein profiling of patients with gastric cancer and healthy individuals and found differential protein expression levels associated with the disease as well as individuals. Given the flexibility of manipulating functional groups on the nanoprobes, their low cost, robustness, and simplicity of the assay, our approach shows promise for targeted proteome profiling in clinical settings.
Purification, tandem mass characterization, and inhibition studies of oxidosqualene-lanosterol cyclase enzyme from bovine liver
(2004-01-01)
Wu, TK
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Huang, CY
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Ko, CY
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Chang, CH
;
Chen, YJ
The oxidosqualene-lanosterol cyclase (OSC) from bovine liver has been isolated from the microsomal membrane fraction and purified to homogeneity by ultracentrifugation, Q-Sepharose, hydroxyapatite, and HiTrap heparin chromatographies. The purified protein required Triton X-100 to retain its highest activity. The cyclase had a molecular mass of similar to70 and similar to140kDa, as evidenced by a single protein band on silver-stained SDS-PAGE and Coomassie-stained PAGE, respectively. Results from Edman degradation of OSC suggested that it might have a blocked N-terminus. Further peptide mapping coupled with tandem mass spectrometric determination identified three peptide fragments, ILGVGPDDPDLVR, LSAEEGPLVQSLR, and NPDGGFATYETK, which are highly homologous to human, rat, and mouse OSCs. The purified cyclase showed pH and temperature optima at pH 7.4 and 37degreesC, respectively. The apparent K-M and k(cat)/K-M values were estimated to be 11 muM and 1.45 mM(-1) min(-1), respectively. Inhibition studies using both Ro48-8071 and N-(4-methylenebenzophenonyl)pyridinium bromide showed potent inhibition of OSC with an IC50 of 11 nM and 0.79 muM, respectively. Results from DTNB modification and DTNB coupled with Ro48-8071 competition study suggest that two sulfhydryl groups are involved in the catalysis but not located in the substrate binding pocket or catalytic active site. The purified OSC was maximally inactivated by diethyl pyrocarbonate near neutral pH and re-activated by hydroxylamine, indicating the modification of histidine residues. The stoichiometry of histidine modification and the extent of inactivation showed that two essential histidine residues per active site are necessary for complete bovine liver OSC activity. (C) 2003 Elsevier Inc. All rights reserved.
Rule combination in a fuzzy neural network
(1996-09-09)
Chen, YJ
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Teng, CC
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交大名義發表
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電控工程研究所
;
National Chiao Tung University
In this paper, we present a fuzzy neural network (FNN) to realize the rule reasoning of fuzzy inference systems. The proposed fuzzy neural network can acquire the fuzzy rules by employing the learning capability of neural networks. Moreover, for simplifying the structure of the proposed FNN, the redundant rules and linguistic terms are removed from the FNN by means of a rule combination procedure. A sufficient condition related to rule combination is also given.
Secure communication mechanisms for GSM networks
(1999-11-01)
Lo, CC
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Chen, YJ
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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
With the advance of wireless communications technology, mobile communications has become more convenient than ever. However, because of the openness of wireless communications, how to protect the privacy between communicating parties is becoming a very important issue. In this paper, we focus on the security of the Global System for Mobile communication (GSM) networks. A secure communication architecture for the GSM network is proposed. In the proposed architecture, we use public-key cryptography for user authentication and stream cipher for message encryption and decryption. An authentication protocol and a key generation method are presented in conjunction with the proposed architecture. Cryptanalysis and operational analysis show that the authentication protocol is secure and efficient. Simulation results indicate that the key generation method can always produce key strings of evenly distributed 0's and 1's and with infinite period.
Simplification of fuzzy-neural systems using similarity analysis
(1996-04-01)
Chao, CT
;
Chen, YJ
;
Teng, CC
;
交大名義發表
;
電控工程研究所
This paper presents a fuzzy neural network system (FNNS) for implementing fuzzy inference systems. In the FNNS, a fuzzy similarity measure for fuzzy rules is proposed to eliminate redundant fuzzy logical rules, so that the number of rules in the resulting fuzzy inference system will be reduced. Moreover, a fuzzy similarity measure for fuzzy sets that indicates the degree to which two fuzzy sets are equal is applied to combine similar input linguistic term nodes. Thus we obtain a method for reducing the complexity of a fuzzy neural network. We also design a new and efficient on-line initialization method for choosing the initial parameters of the FNNS. a computer simulation is presented to illustrate the performance and applicability of the proposed FNNS. The results indicates that the FNNS still has desirable performance under fewer fuzzy logical rules and adjustable parameters.
Spatially resolved relaxation dynamics of photoinduced quasiparticles in underdoped YBa2Cu3O7-delta
(2005-09-01)
Luo, CW
;
Shih, PT
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Chen, YJ
;
Chen, MH
;
Wu, KH
The spatially resolved relaxation characteristics of photoinduced quasiparticles (QPs) in CuO2 planes of underdoped YBCO are disclosed by polarized fs time-resolved spectroscopy. The relaxation time (tau) along b axis diverges at T-c, and appears to be governed by a temperature-dependent gap Delta(T) at T < T-c. Furthermore, for T>T-c, a monotonic increase of tau with decreasing T along the b axis and ab diagonal was observed and can be attributed to a temperature-independent gap Delta(p). The results lend support to the recombination dominant scenario of QP dynamics. However, the QP thermalization may take part along the nodal direction in the highly underdoped samples.
Stream ciphers for GSM networks
(2000)
Lo, CC
;
Chen, YJ
;
資訊管理與財務金融系註：原資管所+財金所
;
Department of Information Management and Finance
With the advance of wireless communications technology, mobile communications has become more convenient than ever. However, because of the openness of wireless communications, how to protect the privacy between communicating parties is becoming a very important issue. In this paper, we focus on the security of transferring voice message on the Global System for Mobile communication (GSM) networks. Stream cipher is recommended for message encryption and decryption. First, a key generator is presented, Then, on the basis of the key generator, stream ciphers pre designed with respect to different levels of securities of GSM networks. Simulation results indicate that the key generator always produces key strings of evenly distributed 0's and 1's and with infinite period. Cryptanalysis and operational analysis show that the proposed stream ciphers are secure and efficient; consequently, they provide a comprehensive set of message encryption/decryption algorithms for GSM networks.
Stream ciphers for GSM networks
(2001-06-15)
Lo, CC
;
Chen, YJ
;
資訊管理與財務金融系註：原資管所+財金所
;
Department of Information Management and Finance
With the advance of wireless communications technology, mobile communications has become more convenient than ever. However, because of the openness of wireless communications, how to protect the privacy between communicating parties is becoming a very important issue. In this paper, we focus on the security of transferring voice message on the Global System for Mobile communication (GSM) networks. Stream cipher is recommended for message encryption and decryption. First, a key generator is presented. Then, on the basis of the key generator, stream ciphers are designed with respect to different levels of securities of GSM networks. Simulation results indicate that the key generator always produces key strings of evenly distributed 0's and 1's and with a very long period; i.e. it is very unlikely that repeated patterns will appear. Cryptanalysis and operational analysis show that the proposed stream ciphers are secure and efficient; consequently, they provide a comprehensive set of message encryption/decryption algorithms for GSM networks. (C) 2001 Elsevier Science B.V. All rights reserved.
The R&D system for industrial development in Taiwan
(2006-06-01)
Jan, TS
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Chen, YJ
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管理科學系
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Department of Management Science
The research and development (R&D) system for industrial development in Taiwan is made up of three parts: industrial firms, government-supported institutes (GSIs), and academic institutes and universities. The Taiwanese experience showed that the effective interaction of the GSIs and the industrial firms has successfully supported the development of its industry. The Industrial Technology Research Institute (ITRI) played the key role in industrial development during recent decades. This study provides a comprehensive analysis of ITRI and the way in which it fulfills its role through an examination of its major tasks. The implications for developing countries are also discussed. (c) 2005 Elsevier Inc. All rights reserved.
Two-photon resonance assisted huge nonlinear refraction and absorption in ZnO thin films
(2005-02-01)
Lin, JH
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Chen, YJ
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Lin, HY
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Hsieh, WF
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光電工程學系
Optical nonlinearities of ZnO thin films, made by laser deposition, were investigated by the Z-scan method using a mode-locked femtosecond Ti:sapphire laser. The measured bound-electron nonlinear index of refraction gamma and the two-photon absorption coefficient beta at near-IR wavelengths show an enormous enhancement compared with measurements on bulk ZnO at 532 nm. The results reveal that two-photon resonance to the band edge and exciton energy level is responsible for the nonlinear absorption and that the free carrier induced the optical nonlinearity. With the excitation wavelength operated between 810 to 840 nm, a negative beta value is measured due to the saturation of linear absorption of the defect states. Finally, we compared the values of beta from the closed aperture Z-scan data (by considering the multi-photon absorption induced thermal nonlinearity) with those obtained from the open aperture Z-scan data. The results show that nonlinear refraction in the near-IR region is dominated by the bound-electron and free-carrier effect, although the thermal optical nonlinearity cannot be completely ignored. (C) 2005 American Institute of Physics.