8664918
Automated design of pin-constrained digital microfluidic arrays for lab-on-a-chip applications
Microfluidics-based biochips, also referred to as lab-on-a-chip (LoC), are devices that integrate fluid-handling functions such as sample preparation, analysis, separation, and detection. This emerging technology combines electronics with biology to open new application areas such as point-of-care diagnosis, on-chip DNA analysis, and automated drug discovery. We propose a design automation method for pin-constrained LoCs that manipulate nanoliter volumes of discrete droplets on a microfluidic array. In contrast to the direct-addressing scheme that has been studied thus far in the literature, we assign a small number of independent control pins to a large number of electrodes in the LoC, thereby reducing design complexity and product cost. We apply the proposed method to a microfluidic array for a set of multiplexed bioassays
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
8296105
Concurrent testing of digital microfluidics-based biochips
We present a concurrent testing methodology for detecting catastrophic faults in digital microfluidics-based biochips and investigate the related problems of test planning and resource optimization. We first show that an integer linear programming model can be used to minimize testing time for a given hardware overhead, for example, droplet dispensing sources and capacitive sensing circuitry. Due to the NP-complete nature of the problem, we also develop efficient heuristic procedures to solve this optimization problem. We apply the proposed concurrent testing methodology to a droplet-based microfluidic array that was fabricated and used to perform multiplexed glucose and lactate assays. Experimental results show that the proposed test approach interleaves test application with the biomedical assays and prevents resource conflicts. The proposed method is therefore directed at ensuring high reliability and availability of bio-MEMS and lab-on-a-chip systems, as they are increasingly deployed for safety-critical applications.
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.
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.
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.
11609039
A Hierarchical Fingerprint Matching Method Based on Rotation Invariant Features
A hierarchical matching algorithm based on rotation invariant features to align two fingerprints is proposed in this paper The translation and rotational offsets are extracted using the maximum overlapped fingerprint images The proposed method can reduce the searching space in alignment, and what is more attractive is that it obviates the need for extracting minutiae points or the core point to align the fingerprint images Experimental results show that the proposed method is more robust than using the reference point or using the minutiae to align the fingerprint images.
13557739
A Robust Fingerprint Minutiae Matching Algorithm Based on the Support Model
A novel method to match two minutiae point-sets based on the support model we proposed is presented in this paper. In this method, coarse matching is first performed from a number of seeds, and the results are then fused to obtain a constrained corresponding relationship of minutiae in two point-sets. By using the support degree of the elements in the constrained relations, the one-to-one correspondence is finally determined by comparison of similarity of local structures. Experiments show that this algorithm is robust and can deal with the translation, rotation, distortion and outlier problems well.
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.
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.
2604877
A Biometric Key-Binding and Template Protection Framework Using Correlation Filters
We describe a new framework to bind cryptographic keys with biometric signatures using correlation filters. This scheme combines correlation filter based biometric recognition with biometric key-binding while offering template protection, revocability, diversity and security. We demonstrate the effectiveness of our scheme via numerical results on the CMU-PIE face database.