28952565
Computer-Aided Design and Test for Digital Microfluidics
This article discusses several aspects of design and test methodology centered on digital microfluidics, including modeling, simulation, synthesis, test, and reconfiguration. The automated design methods for digital electronics and adaption of them to droplet-based microfluidics are explained. The test methodology detects both catastrophic and parametric faults by electrically controlling and tracking the motion of the test stimuli droplets and also facilitates concurrent testing, in which fault testing and biomedical assays run simultaneously on a microfluidic system.
13266891
Unified high-level synthesis and module placement for defect-tolerant microfluidic biochips
Microfluidic biochips promise to revolutionize biosensing and clinical diagnostics. As more bioassays are executed concurrently on a biochip, system integration and design complexity are expected to increase dramatically. This problem is also identified by the 2003 ITRS document as a major system-level design challenge beyond 2009. We focus here on the automated design of droplet-based microfluidic biochips. We present a synthesis methodology that unifies operation scheduling, resource binding, and module placement for such "digital" biochips. The proposed technique, which is based on parallel recombinative simulated annealing, can also be used after fabrication to bypass defective cells in the microfluidic array. A real-life protein assay is used to evaluate the synthesis methodology.
712994
Test Planning and Test Resource Optimization for Droplet-Based Microfluidic Systems
Recent years have seen the emergence of droplet-based microfluidic systems for safety-critical biomedical applications. In order to ensure reliability, microsystems incorporating microfluidic components must be tested adequately. In this paper, we investigate test planning and test resource optimization for droplet-based microfluidic arrays. We first formulate the test planning problem and prove that it is NP-hard. We then describe an optimization method based on integer linear programming (ILP) that yields optimal solutions. Due to the NP-hard nature of the problem, we develop heuristic approaches for optimization. Experimental results indicate that for large array sizes, the heuristic methods yield solutions that are close to provable lower bounds. These heuristics ensure scalability and low computation cost.
53235102
Module placement for fault-tolerant microfluidics-based biochips
Microfluidics-based biochips are soon expected to revolutionize clinical diagnosis, DNA sequencing, and other laboratory procedures involving molecular biology. Most microfluidic biochips today are based on the principle of continuous fluid flow and they rely on permanently etched microchannels, micropumps, and microvalves. We focus here on the automated design of “digital” droplet-based microfluidic biochips. In contrast to conventional continuous-flow systems, digital microfluidics offers dynamic reconfigurability; groups of cells in a microfluidics array can be reconfigured to change their functionality during the concurrent execution of a set of bioassays. We present a simulated annealing-based technique for module placement in such biochips. The placement procedure not only addresses chip area, but also considers fault tolerance, which allows a microfluidic module to be relocated elsewhere in the system when a single cell is detected to be faulty. Simulation results are presented for case studies involving the polymerase chain reaction and multiplexed in vitro clinical diagnostics.
16866295
Defect Tolerance Based on Graceful Degradation and Dynamic Reconfiguration for Digital Microfluidics-Based Biochips
Defect tolerance is an important design consideration for microfluidics-based biochips that are used for safety-critical applications. The authors propose a defect-tolerance methodology based on graceful degradation and dynamic reconfiguration. A tile-based biochip architecture is first introduced, which is scalable for large-scale bioassays. A clustered defect model is used to evaluate the graceful-degradation method for tile-based biochips. The proposed schemes ensure that the bioassays mapped to a droplet-based microfluidic array during design can be executed on a defective biochip through operation rescheduling and/or resource rebinding. Real-life biochemical procedures, namely polymerase chain reaction and multiplexed in vitro diagnostics on human physiological fluids, are used to evaluate the proposed defect-tolerance schemes
1293291
Microfluidics-Based Biochips: Technology Issues, Implementation Platforms, and Design-Automation Challenges
Microfluidics-based biochips are soon expected to revolutionize clinical diagnosis, deoxyribonucleic acid (DNA) sequencing, and other laboratory procedures involving molecular biology. In contrast to continuous-flow systems that rely on permanently etched microchannels, micropumps, and microvalves, digital microfluidics offers a scalable system architecture and dynamic reconfigurability; groups of unit cells in a microfluidics array can be reconfigured to change their functionality during the concurrent execution of a set of bioassays. As more bioassays are executed concurrently on a biochip, system integration and design complexity are expected to increase dramatically. This paper presents an overview of an integrated system-level design methodology that attempts to address key issues in the synthesis, testing and reconfiguration of digital microfluidics-based biochips. Different actuation mechanisms for microfluidics-based biochips, and associated design-automation trends and challenges are also discussed. The proposed top-down design-automation approach is expected to relieve biochip users from the burden of manual optimization of bioassays, time-consuming hardware design, and costly testing and maintenance procedures, and it will facilitate the integration of fluidic components with a microelectronic component in next-generation systems-on-chips (SOCs).
1341088
An optical characterization technique for hygroscopic expansion of polymers and plastic packages
In this paper, we have described a new simultaneous 3-D optical system for characterizing electronic packages. This optical system is able to capture high resolution, online whole field data set. We are able to use this optical system to determine the coefficient of hygroscopic expansion (CHE) in moulding compound by correlating the weight gain and hygro-strain information obtained. In this study, we have used this optical system to evaluate the hygroscopic expansion of a fully cured moulding compound, XJA-9. We have also studied the effect of moisture diffusion on the deformation of plastic IC package. It was found that moisture diffusion could reverse the warpage of the plastic package. The study showed that moisture may cause severe changes to the internal stress field of plastic packages that would usually occur unnoticed or underestimated.
15063481
Eye Location under Various Illumination Conditions
Eye location is an important step in face recognition. Locate eyes under various illumination conditions is also an important step especially for most of illumination normalization algorithms. In this paper, an algorithm uses a group of eigenfeature templates and Gabor feature templates to locate eye under various illumination conditions is proposed. Experiment results show that the performance of this algorithm is good and robust under widely changed illumination conditions
35204150
Ridge-Based Fingerprint Recognition
A new fingerprint, matching method is proposed in this paper, with which two fingerprint skeleton images are matched directly. In this method, an associate table is introduced to describe the relation of a ridge with its neighbor ridges, so the whole ridge pattern can be easily handed. In addition, two unique similarity measures, one for ridge curves, another for ridge patterns, are defined with the elastic distortion taken into account. Experiment results on several databases demonstrate the effectiveness and robustness of the proposed method.
17266009
An Exact Ridge Matching Algorithm for Fingerprint Verification
Unlike traditional minutiae-based fingerprint matching approach, which establishes the minutiae correspondence between two fingerprints, in this paper a novel ridge-based fingerprint matching algorithm, which establishes the exact ridge correspondence between two fingerprints is proposed. The ridge correspondence is called ‘exact' because correspondences between points on ridges are also established. The matching score is computed as the ratio of the length of matched ridges to that of all ridges. Experimental results on FVC2002 databases show that the ridge matching approach performs comparably to minutiae-based one, and an obvious improvement on matching performance can be obtained by combining the two matchers.
23911088
Robust Ridge Following in Fingerprints
In this paper, we presented an improved approach of minutiae detection by following the ridges Our algorithm is based on the two characteristics of the ridge points on the same ridge: connectivity and randomicity Because our algorithm takes full advantage of the characteristics of the ridge points, it is robust to noise Using our algorithm, good quality ridge images can be obtained which can be used to assist minutiae-based fingerprint matching, or directly used for fingerprint matching Experimental results are included.