Lei Zhang

This book describes a range of new biometric technologies, such as high-resolution fingerprint, finger-knuckle-print, multi-spectral backhand, 3D fingerprint, tongueprint, 3D ear, and multi-spectral iris technologies. Further, it introduces readers to efficient feature extraction, matching and fusion algorithms, in addition to developing potential systems of its own. These advanced biometric technologies and methods are divided as follows: 1. High-Resolution Fingerprint Recognition; 2. Finger-Knuckle-Print Verification; 3. Other Hand-Based Biometrics; and 4. New Head-Based Biometrics. Traditional biometric technologies, such as fingerprint, face, iris, and palmprint, have been extensively studied and addressed in many research books. However, all of these technologies have their own advantages and disadvantages, and there is no single type of biometric technology that can be used for all applications. Many new biometric technologies have been developed in recent years, especially in response to new applications. The contributions gathered here focus on how to develop a new biometric technology based on the requirements of essential applications, and how to design efficient algorithms that yield better performance.

This book extends the conventional two-dimensional (2D) magnet arrangement into 3D pattern for permanent magnet linear machines for the first time, and proposes a novel dual Halbach array. It can not only effectively increase the radial component of magnetic flux density and output force of tubular linear machines, but also significantly reduce the axial flux density, radial force and thus system vibrations and noises. The book is also the first to address the fundamentals and provide a summary of conventional arrays, as well as novel concepts for PM pole design in electric linear machines. It covers theoretical study, numerical simulation, design optimization and experimental works systematically. The design concept and analytical approaches can be implemented to other linear and rotary machines with similar structures. The book will be of interest to academics, researchers, R&D engineers and graduate students in electronic engineering and mechanical engineering who wish to learn the core principles, methods, and applications of linear and rotary machines.

This book describes a range of new biometric technologies, such as high-resolution fingerprint, finger-knuckle-print, multi-spectral backhand, 3D fingerprint, tongueprint, 3D ear, and multi-spectral iris technologies. Further, it introduces readers to efficient feature extraction, matching and fusion algorithms, in addition to developing potential systems of its own. These advanced biometric technologies and methods are divided as follows: 1. High-Resolution Fingerprint Recognition; 2. Finger-Knuckle-Print Verification; 3. Other Hand-Based Biometrics; and 4. New Head-Based Biometrics. Traditional biometric technologies, such as fingerprint, face, iris, and palmprint, have been extensively studied and addressed in many research books. However, all of these technologies have their own advantages and disadvantages, and there is no single type of biometric technology that can be used for all applications. Many new biometric technologies have been developed in recent years, especially in response to new applications. The contributions gathered here focus on how to develop a new biometric technology based on the requirements of essential applications, and how to design efficient algorithms that yield better performance.

This book extends the conventional two-dimensional (2D) magnet arrangement into 3D pattern for permanent magnet linear machines for the first time, and proposes a novel dual Halbach array. It can not only effectively increase the radial component of magnetic flux density and output force of tubular linear machines, but also significantly reduce the axial flux density, radial force and thus system vibrations and noises. The book is also the first to address the fundamentals and provide a summary of conventional arrays, as well as novel concepts for PM pole design in electric linear machines. It covers theoretical study, numerical simulation, design optimization and experimental works systematically. The design concept and analytical approaches can be implemented to other linear and rotary machines with similar structures. The book will be of interest to academics, researchers, R&D engineers and graduate students in electronic engineering and mechanical engineering who wish to learn the core principles, methods, and applications of linear and rotary machines.

This thesis examines laser generation from the ultraviolet to the short edge of the mid-infrared band by exploiting the nonlinear effects in photonic crystal fibers (PCFs). Several different physical mechanisms are investigated by using homemade PCFs with elaborately customized dispersion profiles. A particular focus is on the development of fiber optical parametric amplifiers (FOPAs) and oscillators (FOPOs) based on the PCFs with a zero-dispersion wavelength of ca.1.06 µm. In particular, several schemes are proposed for solving the key problems involved in the application of FOPOs. These oscillators can be made more convenient to use by optimizing the wavelength-tuning mechanisms and made more energy-efficient with the help of specially designed cavity structures. Today’s oscillators are more reliable, powerful and maneuverable than ever. This thesis provides a systematic road map in connection with the study of nonlinear wavelength generation in PCFs, from their fiber design and technical fabrication, to their physical mechanism and experimental investigation.

This thesis examines laser generation from the ultraviolet to the short edge of the mid-infrared band by exploiting the nonlinear effects in photonic crystal fibers (PCFs). Several different physical mechanisms are investigated by using homemade PCFs with elaborately customized dispersion profiles. A particular focus is on the development of fiber optical parametric amplifiers (FOPAs) and oscillators (FOPOs) based on the PCFs with a zero-dispersion wavelength of ca.1.06 µm. In particular, several schemes are proposed for solving the key problems involved in the application of FOPOs. These oscillators can be made more convenient to use by optimizing the wavelength-tuning mechanisms and made more energy-efficient with the help of specially designed cavity structures. Today’s oscillators are more reliable, powerful and maneuverable than ever. This thesis provides a systematic road map in connection with the study of nonlinear wavelength generation in PCFs, from their fiber design and technical fabrication, to their physical mechanism and experimental investigation.