Iris segmentation

The quality of eye image data become degraded particularly when the image is taken in the non-cooperative acquisition environment such as under visible wavelength illumination. Consequently, this environmental condition may lead to noisy eye images, incorrect localization of limbic and pupillary boundaries and eventually degrade the performance of iris recognition system. Hence, this study has compared several segmentation methods to address the abovementioned issues. The results show that Circular Hough transform method is the best segmentation method with the best overall accuracy, error rate and decidability index that more tolerant to ‘noise’ such as reflection

Introducing The Small World: Developing The Mems/Nanotechnology Curriculum

© ASEE 2009MEMS (Microelectromechanical Systems) and nanotechnology are believed to be the exciting drive to trigger the next wave of technology revolution. MEMS refer to systems in micro scale (1 micron to 1 millimeter) that integrates mechanical components, sensors, actuators, and electronics on a common silicon substrate through micromachining technology. Due to its low cost, small size, light weight and high resolution, MEMS has been widely used in automobiles, medical health care, aerospace, consumer products and RF communications. Nanotechnology refers to a field of applied science and technology about materials and devices in the atomic and molecular scale, normally 1 to 100 nanometers. It can offer better built, longer lasting, cleanser, safer and smarter products for home, communications, medicine, transportation, agriculture and many other fields. MEMS and nanotechnology can be combined to create a new exciting field of NEMS (Nanoelectromechanical system). In order to introduce engineering students into this amazing micro and nanotechnology field, we developed three corresponding graduate-level courses: Introduction to MEMS (EE446) and Introduction to Nanotechnology (EE451), and Microelectronic Fabrication (EE448). In addition, we have other related courses to support this program, such as EE 447: Semiconductor, EE 404: CMOS VLSI, EE 410: Bio-sensors, etc. This paper will discuss the course structure, syllabuses, course modules, student feedbacks, as well as future plans for this program. This curriculum offer students comprehensive knowledge and experience in MEMS and nanotechnology. Students use various CAD tools such as ANSYS FEM to design and simulate various MEMS/NEMS devices in the course projects. Multimedia technology is also used during the classroom teaching. We played vivid photos/videos to show the operation of MEMS/NEMS devices and state-of-the-art micro/nano fabrication processes in industry. Students demonstrated tremendous interest in this micro/nanotechnology program. The enrollment to these courses has been overwhelming and we have to create extra sessions to accommodate students with strong interest in this program. Our graduated students are well prepared for the industry in micro/nanotechnology fields. This program can also be helpful for the effort of the Connecticut Nanotechnology Curriculum Committee

LI-HE’S MODIFIED HOMOTOPY PERTURBATION METHOD FOR DOUBLY-CLAMPED ELECTRICALLY ACTUATED MICROBEAMS-BASED MICROELECTROMECHANICAL SYSTEM

This paper highlights Li-He’s approach in which the enhanced perturbation method is linked with the parameter expansion technology in order to obtain frequency amplitude formulation of electrically actuated microbeams-based microelectromechanical system (MEMS). The governing equation is a second-order nonlinear ordinary differential equation. The obtained results are compared with the solution achieved numerically by the Runge-Kutta (RK) method that shows the effectiveness of this variation in the homotopy perturbation method (HPM)

Development of dynamic model and control techniques for microelectromechanical gyroscopes

In this thesis we investigate the effects of stiffness, damping and temperature on the performance of a MEMS vibratory gyroscope. The stiffness and damping parameters are chosen because they can be appropriately designed to synchronize the drive and sense mode resonance to enhance the sensitivity and stability of MEMS gyroscope. Our results show that increasing the drive axis stiffness from its tuned value by 50%, reduces the sense mode magnitude by ~27% and augments the resonance frequency by ~21%. The stiffness and damping are mildly sensitive to typical variations in operating temperature. The stiffness decreases by 0.30%, while the damping increases by 3.81% from their initial values, when the temperature is raised from -40 to 60C. Doubling the drive mode damping from its tuned value reduces the oscillation magnitude by 10%, but ~0.20% change in the resonance frequency. The predicted effects of stiffness, damping and temperature can be utilized to design a gyroscope for the desired operating condition

Payload Configuration, Integration and Testing of the Deformable Mirror Demonstration Mission (DeMi) CubeSat

Adaptive optics is an imaging technique that has been used on many ground based telescopes to improve image resolution and reduce the effects of atmospheric turbulence. While adaptive optics has known uses on the ground, applying this technique to space telescopes has major advantages for exoplanet imaging, inter-satellite laser communication, high energy systems, and other military applications. The Deformable Mirror Demonstration Mission (DeMi) is a 6U CubeSat, that will demonstrate the use of adaptive optics, specifically a microelectromechanical system (MEMS) deformable mirror, in space. Not only will the DeMi mission characterize the deformable mirror on-orbit, the mission will also demonstrate deformable mirror control using closed loop image plane sensing and wavefront sensing on internal and external light sources. DeMi uses COTS components like Thorlabs mirrors, Pixelink complementary metal-oxide-semiconductor cameras, and a Boston Micromachines Corporation “multi” deformable mirror. DeMi is currently in the optical integration and testing stage. The payload design and assembly is being tested by assembling 3D printed payload components. Optical alignment and configuration is being tested by mounting the optical components to the 3D printed payload assembly. Current and future testing will inform payload design and payload assembly plan changes. DeMi is expected to launch winter of 2019

Development of a wireless MEMS inertial system for health monitoring of structures

Health monitoring of structures by experimental modal analysis is typically performed with piezoelectric based transducers. These transducers are usually heavy, large in size, and require high power to operate, all of which reduce their versatility and applicability to small components and structures. The advanced developments of microfabrication and microelectromechanical systems (MEMS) have lead to progressive designs of small footprint, low dynamic mass and actuation power, and high-resolution inertial sensors. Because of their small dimensions and masses, MEMS inertial sensors could potentially replace the piezoelectric transducers for experimental modal analysis of small components and structures. To transfer data from MEMS inertial sensors to signal analyzers, traditional wiring methods may be utilized. Such methods provide reliable data transfer and are simple to integrate. However, in order to study complex structures, multiple inertial sensors, attached to different locations on a structure, are required. In such cases, using wires increases complexity and eliminates possibility of achieving long distance monitoring. Therefore, there is a need to implement wireless communications capabilities to MEMS sensors. In this thesis, two different wireless communication systems have been developed to achieve wireless health monitoring of structures using MEMS inertial sensors. One of the systems is designed to transmit analog signals, while the other transmits digital signals. The analog wireless system is characterized by a linear frequency response function in the range of 400 Hz to 16 kHz, which covers the frequency bandwidth of the MEMS inertial sensors. This system is used to perform modal analysis of a test structure by applying multiple sensors to the structure. To verify the results obtained with MEMS inertial sensors, noninvasive, laser optoelectronic holography (OEH) methodology is utilized to determine modal characteristics of the structure. The structure is also modeled with analytical and computational methods for correlation of and verification with the experimental measurements. Results indicate that attachment of MEMS inertial sensors, in spite of their small mass, has measurable effects on the modal characteristics of the structure being considered, verifying their applicability in health monitoring of structures. The digital wireless system is used to perform high resolution tilt and rotation measurements of an object subjected to angular and linear accelerations. Since the system has been developed based on a microcontroller, programs have been developed to interface the output signals of the sensors to the microcontroller and RF components. The system is calibrated using the actual driving electronics of the MEMS sensors, and it has achieved an angular resolution of 1.8 mrad. The results show viability of the wireless MEMS inertial sensors in applications requiring accurate tilt and rotation measurements. Additional results presented included application of a MEMS gyroscope and microcontroller to perform angular rate measurements. Since the MEMS gyroscope only generates analog output signals, an analog to digital conversion circuit was developed. Also, a program has been developed to perform analog to digital conversion with two decimal places of accuracy. The experimental results demonstrate feasibility of using the microcontroller and the gyroscope to perform wireless angular rate measurements

Quantification of mechanical forces and physiological processes involved in pollen tube growth using microfluidics and microrobotics

Pollen tubes face many obstacles on their way to the ovule. They have to decide whether to navigate around cells or penetrate the cell wall and grow through it or even within it. Besides chemical sensing, which directs the pollen tubes on their path to the ovule, this involves mechanosensing to determine the optimal strategy in specific situations. Mechanical cues then need to be translated into physiological signals, which eventually lead to changes in the growth behavior of the pollen tube. To study these events, we have developed a system to directly quantify the forces involved in pollen tube navigation. We combined a lab-on-a-chip device with a microelectromechanical systems-based force sensor to mimic the pollen tube's journey from stigma to ovary in vitro. A force-sensing plate creates a mechanical obstacle for the pollen tube to either circumvent or attempt to penetrate while measuring the involved forces in real time. The change of growth behavior and intracellular signaling activities can be observed with a fluorescence microscope

Microelectronic engineering education for emerging frontiers

With the support provided by the National Science Foundation and RIT Provost’s vision for providing flexible curricula, the department of Microelectronic Engineering has instituted new and enhanced program initiatives – (1) offering a semiconductor processing minor for other science and engineering programs promoting access to state-of-the art semiconductor fabrication facilities to students from other programs; (2) crafting a five course elective sequence within the existing curriculum by eliminating legacy material and course consolidation; (3) developing a concentration program in nanotechnology and MEMS; (4) outreach programs for targeting larger and diverse participation in preparing workforce for the nation’s future high tech industry; (5) enhance student learning through co-op and service. The mission is to generate multi faceted work force for the future semiconductor technologies and emerging frontiers spinning off from microelectronics, while simultaneously promoting enrollment particularly from women and minority students

Silicon photonic MEMS add-drop filter

We demonstrate a compact add-drop filter based on a MEMS ring resonator implemented in IMEC's iSiPP50G silicon photonics platform. The device exhibits a port extinction of 20 dB and a port isolation of > 50 dB, upon actuation range of 0 V to 27 V