Applied Mechanics and Materials Vols. 284-287

Abstract: This thesis is to approach license-plate recognition using 2D Haar Discrete Wavelet Transform (HDWT) and artificial neural network. This thesis consists of three main parts. The first part is to locate and extract the license-plate. The second part is to train the license-plate. The third part is to real time scan recognition. We select only after the second 2D Haar Discrete Wavelet Transform the image of low-frequency part, image pixels into one-sixteen, thus, reducing the image pixels and can increase rapid implementation of recognition and the computer memory. This method is to scan for car license plate recognition, without make recognition of the individual characters. The experimental result can be high recognition rate.

Abstract: The performance of an automatic system for extracting flower boundaries for ten different types of wild flowers has been improved. The proposed flower boundary extraction method consists of three major procedures: the detection of four edge points, boundary tracing and performance improvement part. The flower boundary extraction part involves a new technique for automatically identifying the boundary of a flower in an image. An Intelligent Scissor algorithm is applied for boundary tracing. The color gradient magnitude and Canny edge detection are analyzed and included as the cost terms of the Intelligent Scissor algorithm. The color gradient magnitude cost term is implemented so that it can act directly on the three components of the color image. For the third procedure, we implement performance improvement. The main advantage of the proposed method was that when the program detected the wrong four edge points, using the mouse the correct positions could be clicked. The proposed method was applied to 500 photos of 10 different flowers, with 50 photos of each flower all in a complex background. The experimental results showed an extraction rate of 79.4%, which was better than before.

Abstract: This paper presents a technique to design a PSO guidance algorithm for the nonlinear and dynamic pursuit-evasion optimization problem. In the PSO guidance algorithm, the particle positions of the swarm are initialized randomly within the guidance command solution space. With the particle positions to be guidance commands, we predict and record missiles’ behavior by solving point-mass equations of motion during a defined short-range period. Taking relative distance to be the objective function, the fitness function is then evaluated according to the objective function. As the PSO algorithm proceeds, these guidance commands will migrate to a local optimum until the global optimum is reached. This paper implements the PSO guidance algorithm in two pursuit-evasion scenarios and the simulation results show that the proposed design technique is able to generate a missile guidance law which has satisfied performance in execution time, terminal miss distance, time of interception and robust pursuit capability.

Abstract: In rotary machinery, the symptoms of vibration signals in the frequency domain have been used as inputs for neural networks and diagnosis results can be obtained by network computation. However, in gear or rolling bearing systems, it is difficult to extract symptoms from vibration signals in the frequency domain where shock vibration signals are present, and neural networks do not provide satisfactory diagnosis results without adequate training samples. Bayesian networks provide an effective approach for fault diagnosis in cases given uncertain knowledge and incomplete information. To classify the shock of vibration signals in the gear system, this study uses statistical factors of vibration signals. Based on these factors, the fault diagnosis is implemented by using Bayesian networks and the results of the two methods, namely, back-propagation neural networks and probabilistic neural network in gear train systems, are compared.

Abstract: In this paper, a 3.5 GHz CMOS sub-harmonic mixer for LTE-advanced applications is presented. The mixer with the bulk-controlled technique improves the linearity and mitigates the power of the local oscillator. The proposed mixer is implemented by tsmc 0.18 μm Mixed Signal RF CMOS 1P6M process and consumes 2.2 mA from a 1.2 V supply. The proposed mixer operates at 3.5GHz LTE-advanced bands and achieves maximum input third-order intercept point (IIP3) of 2.3dBm, power conversion gains of 1.3 dB.

Abstract: The continuously growing of semiconductor technology makes the novel SOC system complicated and hard to design. Conventional timing-control methodology focuses on the synchronizing the registers in a digital system. However, the central control of huge amount of synchronous signals and states is difficult to maintain and design, the debugging and verification period is extended accordingly. This paper proposed a novel deign methodology, called data-oriented methodology, to overcome the above challenges, by using Bluespec SystemVerilog and the corresponding tools. The simple handshaking mechanism and blocking mechanism are adopted to make sure the correctness of adjacent blocks, the complex centralized control unit can be reduced accordingly. Two examples, FDCT/IDCT and pipelined MIPS CPU, are provided to demonstrate two types of typical digital designs.

Abstract: A fast power factor detector for nonlinear loads is proposed to overcome the drawback of conventional detectors, which can measure only the power factor of linear loads. The design of the proposed detector is based on the concept of additional characteristic of trigonometric function. It does not require any low-pass filter or integrator. Therefore, the transient response of the proposed detector is much faster than that of the conventional detectors. The theoretical response time of the proposed detector is less than one-fourth of a cycle. Because of its promising accuracy and rapid transient response, it can be used in many systems such as the control of power systems, and active power filters, to improve their transient performance. Theoretical analysis and experimental results are also detailed in this paper.

Abstract: This paper proposed a novel single-phase soft-switching unipolar PWM rectifier (SSUPR) using a simple auxiliary resonant unit. All main switches of high-frequency arm operate at zero-voltage-switching (ZVS) turn-on, while the auxiliary switches operate at zero-current-switching (ZCS) turn-off. All main switches of low-frequency arm operate at 60 Hz to greatly reduce switching losses. Moreover, a soft-switching unipolar PWM strategy is used for the proposed soft-switching rectifier. This strategy results in a better input current waveform than for the bipolar PWM strategy. Furthermore, the proposed rectifier achieves a near unity power factor, a sinusoidal input current and a bidirectional power flow capability. Some experimental results of the proposed SSUPR, rated 500 W and operated at 40 kHz, are presented for verification.

Abstract: This paper proposed a single-stage single-switch ac-to-dc converter which is derived by integrating a boost converter and a flyback converter. Only one active switch and simple control are required. The boost converter performs as a power-factor corrector (PFC) which is designed to operate at discontinue-conduction mode (DCM) to makes the input current be a sinusoidal waveform and in phase with the input voltage. High power factor and low total current harmonic distortion (THD) are ensured. The flyback converter further regulates the output voltage of the boost converter to provide an isolated dc voltage with low voltage ripple. The flyback converter is designed to operate at continue-conduction mode (CCM) to have the transformer current of a low peak value. It will be effectively reduce the switching stress and the switching losses of semiconductor components. The paper conducts the mathematical equations for the converter circuits, and then designing the circuit parameters. A prototype circuit designed for a 100 W output power was built and tested. Satisfactory results are obtained experimentally.

Abstract: This paper presents a practical new method to quickly and effectively eliminate coordination curve intersection problems in subtransmission systems resulting from improper protective coordination settings in electromechanical overcurrent relays. Firstly, a database representing the relay operating characteristics was constructed based on the electromechanical overcurrent relay characteristic curves published by the manufacturer. Then, combining with this database, a fixed-point coordination curve adjustment procedure dedicated to electromechanical overcurrent relays was proposed to tackle the curve intersection situation of the coordinated upstream and downstream relay pair appearing in the original design. In addition to correcting manmade errors that could cause unexpected widespread power outages when fault occurs, the proposed technique can also enhance the effectiveness and accuracy of coordination. This study also simulated an actual case in Taiwan Power Company to verify the feasibility and practicality of the proposed method.