Chin-Wen Liao

A Delay-Dependent Approach to Passivity Analysis for Uncertain Neural Networks with Time-varying Delay

This paper deals with the problem of passivity analysis for neural networks with time-varying delay, which is subject to norm-bounded time-varying parameter uncertainties. The activation functions are supposed to be bounded and globally Lipschitz continuous. Delay-dependent passivity condition is proposed by using the free-weighting matrix approach. These passivity conditions are obtained in terms of linear matrix inequalities, which can be investigated easily by using standard algorithms. Two illustrative examples are provided to demonstrate the effectiveness of the proposed criteria.

Implementation of gray image encryption with pixel shuffling and gray-level encryption by single chaotic system

When the grays of images present a strong contrast, merely encrypting the gray-level of image pixels is unable to eliminate the image outlines. The adoption of pixel shuffling can eliminate the image outlines, but cannot disrupt the characteristics of gray-level spectrum. Since a chaotic system is highly sensitive to the initial values and the chaotic trajectory is unpredictable, the application of this method to communication encryption and decryption renders a high level of security. In this paper, the chaotic system is adopted as the fundamental base and combined with row, column shuffling, and gray-level encryption to not only eliminate image outlines, but also disrupt the distributional characteristics of gray level, and the resulting increases of key space. Various statistical methods, such as correlation coefficient, NPCR (Number of Pixels Change Rate), UACI (Unified Average Changing Intensity), and entropy, provide analysis of the efficacy of the encryption method proposed. Our example reveals that the proposed encryption method can obtain highly secure encrypted images.

Direct Torque Control for a Matrix Converter Based on Induction Motor Drive Systems

The paper proposes a direct torque control (DTC) scheme for a matrix-converter-fed induction motor drive system. DTC is a high performance motor control scheme with fast torque and flux responses. However, the main disadvantage of conventional DTC is electromagnetic torque ripple. Besides, the matrix converter is a single-stage ac-ac power conversion device without dc-link energy storage elements. Due to the properties of the matrix converter, the pseudo dc-link will provide with three different types of voltage: the high, middle, and low voltages. Therefore, based on space vector modulation generated by a matrix converter, there are three states on each space vector location. By suitably selecting switching pattern, the electromagnetic torque ripple of the motor is effectively reduced. Using this switching strategy, the advantages of the DTC schemes and the benefits of the matrix converters can be combined. As a result, a satisfactory servo drive can be achieved.

Design of delay-range-dependent robust controller for uncertain genetic regulatory networks with interval time-varying delays

This paper investigates the problem of robust stabilization for genetic regulatory networks with interval time-varying delays, which are subject to norm-bounded time-varying parameter uncertainties. The time delays including lower and upper bounds of delay are assumed to appear in both the mRNA and protein. The regulatory functions are assumed to be globally Lipschitz continuous. The resulting delay-range-dependent robust controller with interval range is designed in terms of improved bounding technique. A sufficient condition for the solvability of the problem is obtained via a linear matrix inequality (LMI). When this LMI is feasible, an explicit expression of a desired state feedback controller is also given. The theory developed in this paper is demonstrated by two numerical examples.

Delay-Range-Dependent Global Robust Passivity Analysis of Discrete-Time Uncertain Recurrent Neural Networks with Interval Time-Varying Delay

This paper examines a passivity analysis for a class of discrete-time recurrent neural networks (DRNNs) with norm-bounded time-varying parameter uncertainties and interval time-varying delay. The activation functions are assumed to be globally Lipschitz continuous. Based on an appropriate type of Lyapunov functional, sufficient passivity conditions for the DRNNs are derived in terms of a family of linear matrix inequalities (LMIs). Two numerical examples are given to illustrate the effectiveness and applicability.

Modeling of a Taiwan fuel cell powered scooter

This paper discusses the importance of a simulation study of the Taiwan Electrical Fuel Cell Power Scooter. This study applies a more detailed modeling which is complex as existing modeling methods, yet not more difficult to solve numerically. In most simulation studies, the influence of non-linearity (for example, saturation, losses, reluctance effects) of the power electronics and electrical machine are neglected. Therefore the simulation results are only valid in the ideal case. Especially the influence of losses, harmonics, saturation, reluctance and time delay in the control, can be a decisive factor in the design. Therefore in this simulation study, it is shown to include these details. The conduction and switching losses in the power electronics during the drive cycle are simulated. Also the temperature stress on the semiconductors will be calculated in order to give a prediction of the life time of the semiconductor modules. Influence of the saturation and reluctance in the electrical machine and the impact on the overall system performance as well as the influence in the field oriented control. Detailed modeling of the field oriented control is discussed. Finally the implementation of the digital control in hardware directly from the simulation control model will be explained.

Passivity Analysis for Uncertain Time-Varying Delayed Neural Networks with Neutral Type

This paper considers the problem of robust delay-dependent passivity analysis for time-varying delayed neural networks described by nonlinear delay differential equations of the neutral type, which is subject to norm-bounded time-varying parameter uncertainties. The activation functions are supposed to be bounded and globally Lipschitz continuous. Both delay-dependent and delay-independent passivity conditions are proposed by using more general Lyapunov-Krasovskii functionals. These passivity conditions are obtained in terms of linear matrix inequalities, which can be investigated easily by recently using standard algorithms. An illustrative example is provided to demonstrate the effectiveness and the reduced conservatism of the proposed method.

Virtual Impedance Analyzer Design and Implementation

In this research, the structure and design of virtual impedance analyzers are studied. The construction process is also described and introduced. This programmable virtual impedance analyzer is achieved by software part, Labview, hardware part, DAQ card and some external circuits. The measurement functions include: (1) impedance [Z] display that has magnitude, phase, impedance and reactance, (2) display settings that has visible section and scale, (3) measurement frequency control, (4) run button, and (5) display window. In the illustrations, demonstrate the design of front panels and also proceed the measurement test of designed virtual impedance analyzer to show the capabilities.

Developing an industry-oriented safety curriculum using the Delphi technique

In this study, we examined the development of industry-oriented safety degree curricula at a college level. Based on a review of literature on the practices and study of the development of safety curricula, we classified occupational safety and health curricula into the following three domains: safety engineering, health engineering, and safety and health management. We invited 44 safety professionals to complete a four-round survey that was designed using a modified Delphi technique. We used Chi-square statistics to test the panel experts’ consensus on the significance of the items in the three domains and employed descriptive statistics to rank the participants’ rating of each item. The results showed that the top three items for each of the three domains were Risk Assessment, Dangerous Machinery and Equipment, and Fire and Explosion Prevention for safety engineering; Ergonomics, Industrial Toxicology, and Health Risk Assessment for health engineering; and Industrial Safety and Health Regulations, Accident Investigation and Analysis, and Emergency Response for safety and health management. Only graduates from safety programmes who possess practical industry-oriented abilities can satisfy industry demands and provide value to the existence of college safety programmes.

Study of contactless power supply for wireless mouse

This paper discuses the printed circuit board (PCB) winding of the contactless power transmission system comparing the traditional transformer power transmission system. In this study, the contactless power transmission system is successfully applied to the wireless mouse for stable power supply. To examine the feasibility of the proposed system in this paper, a contactless power transmission system is developed with 10 W of contactless coupling transformer in primary input power and 0.2 W of secondary output power, which are about 2% efficiency. However, the design of contactless power supply for wireless mouse can be used under the mouse pad to decrease battery consumption and reach the purpose of energy saving, carbon reduction, and environmental protection.