19 research outputs found

    Harnessing Simulation Acceleration to Solve the Digital Design Verification Challenge.

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    Today, design verification is by far the most resource and time-consuming activity of any new digital integrated circuit development. Within this area, the vast majority of the verification effort in industry relies on simulation platforms, which are implemented either in hardware or software. A "simulator" includes a model of each component of a design and has the capability of simulating its behavior under any input scenario provided by an engineer. Thus, simulators are deployed to evaluate the behavior of a design under as many input scenarios as possible and to identify and debug all incorrect functionality. Two features are critical in simulators for the validation effort to be effective: performance and checking/debugging capabilities. A wide range of simulator platforms are available today: on one end of the spectrum there are software-based simulators, providing a very rich software infrastructure for checking and debugging the design's functionality, but executing only at 1-10 simulation cycles per second (while actual chips operate at GHz speeds). At the other end of the spectrum, there are hardware-based platforms, such as accelerators, emulators and even prototype silicon chips, providing higher performances by 4 to 9 orders of magnitude, at the cost of very limited or non-existent checking/debugging capabilities. As a result, today, simulation-based validation is crippled: one can either have satisfactory performance on hardware-accelerated platforms or critical infrastructures for checking/debugging on software simulators, but not both. This dissertation brings together these two ends of the spectrum by presenting solutions that offer high-performance simulation with effective checking and debugging capabilities. Specifically, it addresses the performance challenge of software simulators by leveraging inexpensive off-the-shelf graphics processors as massively parallel execution substrates, and then exposing the parallelism inherent in the design model to that architecture. For hardware-based platforms, the dissertation provides solutions that offer enhanced checking and debugging capabilities by abstracting the relevant data to be logged during simulation so to minimize the cost of collection, transfer and processing. Altogether, the contribution of this dissertation has the potential to solve the challenge of digital design verification by enabling effective high-performance simulation-based validation.PHDComputer Science and EngineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/99781/1/dchatt_1.pd

    Mycobacterium tuberculosis directs T helper 2 cell differentiation by inducing interleukin-1β production in dendritic cells

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    Mycobacterium tuberculosis (M. tb), the causative agent of tuberculosis (TB), resides and replicates within phagocytes and persists in susceptible hosts by modulating protective innate immune responses. Furthermore, M. tb promotes T helper 2(Th2) immune responses by altering the balance of T cell polarising cytokines in infected cells. However, cytokines that regulate Th2 cell differentiation during TB infection remain unknown. Here we show that IL-1β produced by phagocytes infected by virulent M. tb strain H37Rv directs Th2 cell differentiation. In sharp contrast, the vaccine strain BCG as well as RD-1 and ESAT-6 mutants of H37Rv failed to induce IL-1β and promote Th2 cell differentiation. Furthermore, ESAT-6 induced IL-1β production in dendritic cells, and CD4+ T cells co-cultured with infected DCs differentiated into Th2 cells. Taken together our findings indicate that IL-1β induced by RD-1/ESAT-6 plays an important role in the differentiation of Th2 cells, which in turn facilitates progression of TB by inhibiting host protective Th1 responses

    Exploiting Safe Error based Leakage of RFID Authentication Protocol using Hardware Trojan Horse

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    Radio-Frequency Identification tags are used for several applications requiring authentication mechanisms, which if subverted can lead to dire consequences. Many of these devices are based on low-cost Integrated Circuits which are designed in off-shore fabrication facilities and thus raising concerns about their trust. Recently, a lightweight entity authentication protocol called LCMQ was proposed, which is based on Learning Parity with Noise, Circulant Matrix, and Multivariate Quadratic problems. This protocol was proven to be secure against Man-in-the-middle attack and cipher-text only attacks. In this paper, we show that in the standard setting, although the authentication uses two mm bit keys, K1\mathbf{K_1} and K2\mathbf{K_2}, knowledge of only K2\mathbf{K_2} is sufficient to forge the authentication. Based on this observation, we design a stealthy malicious modification to the circuitry based on the idea of Safe-errors to leak K2\mathbf{K_2} and thus can be used to forge the entire authentication mechanism. We develop a Field Programmable Gate Array prototype of the design which is extremely lightweight and can be implemented using four Lookup tables

    Novel custom designed toric piggyback intraocular lens for the correction of residual postoperative astigmatism

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    We report the outcomes of a custom-designed toric piggyback intraocular lens in a patient with high postoperative residual astigmatism. A 60-year-old male patient underwent customized toric piggyback IOL for postoperative residual astigmatism of 13 D, with follow-up examinations for IOL stability and refractive outcomes. The refractive error stabilized at two months and remained stable at one year, with a correction of nearly 9 D of astigmatism. The IOP remained within normal limits, and there were no postoperative complications. The IOL remained stable in the horizontal position. To our knowledge, this is the first case report of correction of unusually high astigmatism by a novel smart toric design of piggyback IOL

    Unilateral situs inversus of optic disc associated with reduced binocularity and stereoacuity resembling monofixation syndrome

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    Situs inversus of the optic disc is a rare, usually bilateral, congenital embryological abnormality associated with high myopia, optic disc coloboma or tilted optic disc. It is characterized by emergence of the retinal vessels in an anomalous direction with dysversion of the optic disc. In this report we present a 13-year-old boy diagnosed with isolated, unilateral situs inversus of the optic disc associated with reduced binocularity and stereoacuity resembling a monofixation syndrome. The clinicians should be aware of this association and assess the binocularity in patients with unilateral optic disc or macular anomalies. Conversely, patients with reduced binocularity and stereoacuity should be carefully evaluated for macular or optic nerve anomalies, if not associated with strabismus, anisometropia and eccentric fixation. Typical fundus picture, optical coherence tomography and multifocal electro retinogram of the patient would be instructive to a clinician
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