Samuel J. Dickerson

A classroom-based simulation-centric approach to microelectronics education

Introductory courses in microelectronic circuits are integral components to electrical and computer engineering undergraduate curriculums. The nature of the material is well‐suited for the incorporation of simulation tools to enhance student understanding of core concepts. SPICE is an electrical circuit simulation tool that has been widely adopted for industrial applications and education. In many instances, engineering instructors have used SPICE‐based simulation tools for homework problems, laboratory exercises, and course projects. Although generally accepted as beneficial to electronics education, the use of SPICE simulation tools is typically restricted to these types of assignments and not heavily used for classroom activity. In this paper, we present a novel method for incorporating SPICE simulation tools into the classroom. Specifically, in a summer 2017 microelectronics course, we used simulation tools for all aspects of the course, incorporating simulation into lecture, in‐class active learning, as well as assignments, and projects. To evaluate this approach, we carried out a rigorous, comprehensive study of this pedagogical approach on student learning, and perspectives using a variety of direct and indirect assessment methods. The results across all measures showed substantial benefits for students to using this methodology and positive responses to the active learning. Beyond microelectronics and other electrical and computer engineering courses, this approach can be applied to other STEM courses where complex systems are studied and simulation tools for these systems are readily accessible to students.

3D integrated circuits for lab-on-chip applications

We present the designs of two new lab-on-chip devices that use 3D integrated circuit technology to support the separation, purification, and assay of biological particles. Our technique is based on a nanoscale implementation of dielectrophoresis. The key feature of our designs is the use of fabrication features found in 3D technology to create on-chip, nanoscale electrode arrays. The capabilities of our designs are demonstrated with multi-physics simulations of the chips sorting heterogeneous mixtures of HSV-1 capsids.

Efficient optical communications using multibit differential signaling

We present an alternative signaling method for multi-channel fiber ribbon based optical links. The method is based on a hybrid of differential signaling and single-ended channels. Channels are grouped into code blocks of n-bits. Each code word transmitted in the block is restricted to conform to an n choose m rule. Electrical drivers steer current between m active VCSELS with no dummy loads. A virtual reference is synthesized from the received signals and used for differential discrimination. This signaling method approaches the signal-to-noise characteristics of fully differential signaling but can be implemented with significantly lower channel overhead, giving as much as a 33% reduction in fiber count and a 44% reduction in power. Further, code utilization rates on these links can be as low as 51%, leaving substantial code space available for ECC or channel management functions. In this paper, we describe the signaling method and present a prototype transceiver chip. The transceiver is implemented in 0.25um UTSi Silicon-on-Sapphire technology with flip-chip bonded VCSEL and photodetector arrays. The design demonstrates a pin-compatible alternative to the POP4-MSA transceiver standard with 125% greater data throughput and 25% better power efficiency.

Detecting spatial defects in colored patterns using self-oscillating gels

With the growing demand for wearable computers, there is a need for material systems that can perform computational tasks without relying on external electrical power. Using theory and simulation, we design a material system that “computes” by integrating the inherent behavior of self-oscillating gels undergoing the Belousov–Zhabotinsky (BZ) reaction and piezoelectric (PZ) plates. These “BZ-PZ” units are connected electrically to form a coupled oscillator network, which displays specific modes of synchronization. We exploit this attribute in employing multiple BZ-PZ networks to perform pattern matching on complex multi-dimensional data, such as colored images. By decomposing a colored image into sets of binary vectors, we use each BZ-PZ network, or “channel,” to store distinct information about the color and the shape of the image and perform the pattern matching operation. Our simulation results indicate that the multi-channel BZ-PZ device can detect subtle differences between the input and stored patterns, such as the color variation of one pixel or a small change in the shape of an object. To demonstrate a practical application, we utilize our system to process a colored Quick Response code and show its potential in cryptography and steganography.With the growing demand for wearable computers, there is a need for material systems that can perform computational tasks without relying on external electrical power. Using theory and simulation, we design a material system that “computes” by integrating the inherent behavior of self-oscillating gels undergoing the Belousov–Zhabotinsky (BZ) reaction and piezoelectric (PZ) plates. These “BZ-PZ” units are connected electrically to form a coupled oscillator network, which displays specific modes of synchronization. We exploit this attribute in employing multiple BZ-PZ networks to perform pattern matching on complex multi-dimensional data, such as colored images. By decomposing a colored image into sets of binary vectors, we use each BZ-PZ network, or “channel,” to store distinct information about the color and the shape of the image and perform the pattern matching operation. Our simulation results indicate that the multi-channel BZ-PZ device can detect subtle differences between the input and stored patter...

Joint assessment and evaluation of senior design projects by faculty and industry

Most engineering programs culminate in a capstone senior design project that are often evaluated only by faculty despite the fact that the majority of the graduating seniors will be transitioning to careers in industry. In this paper, we demonstrate an innovative educational assessment tool for simultaneously integrating industry and faculty in-person evaluations of senior design projects. Two rubrics were created and aligned to evaluate how well the students satisfied expected student outcomes for senior design: one for use by faculty members and the other for use by industry judges. These rubrics enable in-person in-depth evaluations of the senior design projects at the end-of-semester project showcase. These rubrics were aligned using ABET student learning outcomes. Roughly 30 senior design projects received a combined total of 200 evaluations from both faculty and industry to ensure that each project was evaluated across all criteria by both groups of evaluators. In our assessment tool, industry and faculty scores for each project were plotted in two dimensions to visualization of the degree of correspondence. The strength of alignment between faculty and industry is indicated by the slope of the mean line and the sample variance from this line. Additionally, the Cohens kappa inter-rater reliability statistic is used. This assessment tool can be used to highlight areas of improvement for departments and senior design programs.

Dielectrophoresis-based classification of cells using multi-target multiple-hypothesis tracking

In this paper we present a novel methodology for classifying cells by using a combination of dielectrophoresis, image tracking and classification algorithms. We use dielectrophoresis to induce unique motion patterns in cells of interest. Motion is extracted via multi-target multiple-hypothesis tracking. Trajectories are then used to classify cells based on a generalized likelihood ratio test. We present results of a simulation study and of our prototype tracking the dielectrophoretic velocities of cells.

A multi-target tracking sensor platform for dielectrophoresis-based characterization of cells

In this paper, we present a sensor platform for characterizing cells using dielectrophoresis. With our approach, we use a multi-target multiple-hypothesis tracking algorithm to automatically capture dielectrophoresis velocity information about the cells contained in a mixture. The algorithm we implemented is scalable and suitable for use with real-world samples where there is a high concentration of cells to characterize. We implement our method as a compact, low-power device that can be used in point-of-care applications and present results of the sensor platform characterizing yeast cells.

Nondestructive optical assay method for nanoscale biological particles in solution

In this paper, we present an optical system for non-destructive assay of nanoscale biological particles (viruses) in fluids. This method is part of the design of a novel lab-on-chip device[1] that enables microbiologists to purify, isolate and assay mixtures of viruses without the use of destructive labeling techniques or direct observations using electron microscopy. Our approach is based on the fabrication of large (103 scale) and very dense (100nm scale) electrode arrays using the semiconductor layers of a lab-on-chip die. This array, see Figure 1, is the platform for dielectrophoresis (DEP) based methods for sorting the mixtures of bioparticles and arranging the particles by type into groups at various regions of the electrode array. Based on the DEP field configuration, each group of particles organizes into a set of lines between specific pairs of electrodes with the lines repeated in a spatially periodic pattern. These lines of particles, shown in Figure 2, along with the electrodes themselves, form a diffraction grating, where the efficiency of the grating is directly related to the density of the particles captured between the electrodes. By measuring the optical power in the 1st order diffraction mode of the grating before and after a separation (with and without particles) we can make an indirect measurement of the density of particles trapped in that region of the electrode array. The method works in both reflective mode, for CMOS 3D-IC chip stacks (Figure 1) or transmissive mode for SoS-based transparent substrate devices (Figure 3a).

CAD Tools for Multi-Domain Systems on Chips

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