315 research outputs found

    Choose-Your-Own Adventure: A Lightweight, High-Performance Approach To Defect And Variation Mitigation In Reconfigurable Logic

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    For field-programmable gate arrays (FPGAs), fine-grained pre-computed alternative configurations, combined with simple test-based selection, produce limited per-chip specialization to counter yield loss, increased delay, and increased energy costs that come from fabrication defects and variation. This lightweight approach achieves much of the benefit of knowledge-based full specialization while reducing to practical, palatable levels the computational, testing, and load-time costs that obstruct the application of the knowledge-based approach. In practice this may more than double the power-limited computational capabilities of dies fabricated with 22nm technologies. Contributions of this work: • Choose-Your-own-Adventure (CYA), a novel, lightweight, scalable methodology to achieve defect and variation mitigation • Implementation of CYA, including preparatory components (generation of diverse alternative paths) and FPGA load-time components • Detailed performance characterization of CYA – Comparison to conventional loading and dynamic frequency and voltage scaling (DFVS) – Limit studies to characterize the quality of the CYA implementation and identify potential areas for further optimizatio

    DARPA Urban Challenge, a C++ based platform for testing Path Planning Algorithms: An application of Game Theory and Neural Networks

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    The DARPA Grand Challenge in which the Cornell Racing Team participates requires the completion of a Simulator, which purports all errors in the artificial intelligence path planning down below and back up. The simulator comes as the last layer in the top down approach followed by the Cornell Racing Team. The Strategic layer is charged of global route planning, the tactical layer of collision avoidance and maneuver planning, while the operational layer controls lane tracking and safe following. The simulator is the last layer. Through a COBRA interface the C++ or C# version of the simulator will be receiving commands from the Artificial Intelligence Strategic Layer concerning maneuvers such as Turn Left, Turn Right, Change Lane, Increase Speed, and Stop. The simulator induces from its current situation, using controls such as bounding boxes and the World class, pointing to every object in the World, a set of more detailed commands. Apart from writing a simplified version of the simulator in C++, we also concentrated my efforts onto finding a solution aside from dynamic programming for Path Planning and the Behavioral Modeling of Visible and Neighboring Vehicles on the road network. We have built an efficient and self-correcting C++ GUI Interface including some random moving vehicles as well as a smart vehicle named Autosmart. The Path Planning algorithm is written and implemented although may be missing a more significant round of testing. To do so, we are using the approach of game theory and artificial intelligence’s neural networks. We represent the world as nature, resulting in decisions independent of the drivers (types: turn left or right at the next intersection); nature being in this case the DARPA Challenge organizers. Moreover the drivers chose their behaviors (aggressive, altruist) on the road and keep updating their anticipations about the other players behavior and types, as mentioned above. The end result is to train these neural networks to react to previously categorized behaviors and situations by storing necessary information about the ‘game’. Every player runs its own network, although in our case we limited the simulation to one smart vehicle, Autosmart and 2 random vehicles; therefore by nature the algorithm the algorithm would lead to biased results. It is meant for simplicity since if not for programming the set of commands which lead to adequate behavior at intersections and on segments, such as being done for the smart vehicle; sometimes the random vehicles get into trouble, being too much off the road network. In most cases, the simulator will self-correct their path however

    Endogènisation des comportements migratoires des travailleurs qualifies induits par l’implantation des multinationales au Sud.

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    Let us follow Romer’s framework (1990) for the intermediate goods sector. We assume the following. A North operated multinational firm is implanted in the North and the South. The North designs and makes the higher quality products. In the South, its manufacturing divisions produce intermediate and final goods of lower quality competing against the South locals. The multinational is constrained by the South government to transfer a certain amount of knowhow Hns and technology xns. It also benefits from the large pool of cheaper labor, and leads the efforts of innovation in the South. Final goods and intermediate goods are tradable, although some restrictions may apply on the part which is technologically advanced. The countries, independently of the multinational and of its South competitor, still produce non tradable goods, to which quality rankings do not apply, because they depend on local taste. The workers in the North and the South thereby benefit from both types of goods, tradable and non tradable. Competitors in the South reverse-engineer the goods produced in the South and compete with the North on the final goods market which may be tariff protected, selling back to the North operated multinational firm, or on the intermediate goods market in the South. To the difference of Currie et al (1999, 1996), but similarly to our first model’s assumption that the rate of absorption of the North’s human capital is endogenous to the importance of foreign capital investment, the present model inspired by Ahmid Datta’s model illustrates the mechanism of endogenous absorption through reverse-engineering of foreign designed goods. Conclusions of the original Ahmid Datta’s 2005 model were that a threshold of accumulated human capital knowledge must exists, before the local human capital and imported technology become substitutes from being complements. We clearly reach to the same conclusion here. This finding is consistent with the role given to human capital by Keller 1996. We here strive to demonstrate our first model hypothesis by analyzing: - The effect of the multinational’s decision of foreign investment on the threshold(imitation to innovation state). - The effect of international migration of qualified workers on the threshold. - The effect of Northern consumer’s bias for local made products, on the threshold. - How does the constraint imposed on the multinational to transfer technology and know-how, translate on its profits, on its market share in the South

    US and MR imaging features of benign cystic mesothelioma of the liver: A diagnostic dilemma

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    Cystic mesotheliomas are benign neoplasms, often seen in the parietal and visceral peritoneum, omentum and pelvic organs, and are exceedingly rare in the liver. It is however important to be familiar with the radiological findings of this tumour because the signal-intensity and enhancement pattern of this tumor are unusual and not typical for any of the more frequently seen mass lesions. In our patient, characteristic imaging findings on dynamic contrast-enhanced MRI and histopathological confirmation with appropriate immunohistochemical markers facilitated a correct diagnosis. We herein describe the clinical, imaging and histopathological features, pathogenesis, differential diagnosis and treatment of benign cystic mesothelioma involving posterior segment of the right lobe of the liver

    Packet Switched vs. Time Multiplexed FPGA Overlay Networks

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    Dedicated, spatially configured FPGA interconnect is efficient for applications that require high throughput connections between processing elements (PEs) but with a limited degree of PE interconnectivity (e.g. wiring up gates and datapaths). Applications which virtualize PEs may require a large number of distinct PE-to-PE connections (e.g. using one PE to simulate 100s of operators, each requiring input data from thousands of other operators), but with each connection having low throughput compared with the PE’s operating cycle time. In these highly interconnected conditions, dedicating spatial interconnect resources for all possible connections is costly and inefficient. Alternatively, we can time share physical network resources by virtualizing interconnect links, either by statically scheduling the sharing of resources prior to runtime or by dynamically negotiating resources at runtime. We explore the tradeoffs (e.g. area, route latency, route quality) between time-multiplexed and packet-switched networks overlayed on top of commodity FPGAs. We demonstrate modular and scalable networks which operate on a Xilinx XC2V6000-4 at 166MHz. For our applications, time-multiplexed, offline scheduling offers up to a 63% performance increase over online, packet-switched scheduling for equivalent topologies. When applying designs to equivalent area, packet-switching is up to 2× faster for small area designs while time-multiplexing is up to 5× faster for larger area designs. When limited to the capacity of a XC2V6000, if all communication is known, time-multiplexed routing outperforms packet-switching; however when the active set of links drops below 40% of the potential links, packet-switched routing can outperform time-multiplexing

    GraphStep: A System Architecture for Sparse-Graph Algorithms

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    Many important applications are organized around long-lived, irregular sparse graphs (e.g., data and knowledge bases, CAD optimization, numerical problems, simulations). The graph structures are large, and the applications need regular access to a large, data-dependent portion of the graph for each operation (e.g., the algorithm may need to walk the graph, visiting all nodes, or propagate changes through many nodes in the graph). On conventional microprocessors, the graph structures exceed on-chip cache capacities, making main-memory bandwidth and latency the key performance limiters. To avoid this “memory wall,” we introduce a concurrent system architecture for sparse graph algorithms that places graph nodes in small distributed memories paired with specialized graph processing nodes interconnected by a lightweight network. This gives us a scalable way to map these applications so that they can exploit the high-bandwidth and low-latency capabilities of embedded memories (e.g., FPGA Block RAMs). On typical spreading activation queries on the ConceptNet Knowledge Base, a sample application, this translates into an order of magnitude speedup per FPGA compared to a state-of-the-art Pentium processor

    Terrorism in Australia: factors associated with perceived threat and incident-critical behaviours

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    <p>Abstract</p> <p>Background</p> <p>To help improve incident preparedness this study assessed socio-demographic and socio-economic predictors of perceived risk of terrorism within Australia and willingness to comply with public safety directives during such incidents.</p> <p>Methods</p> <p>The terrorism perception question module was incorporated into the New South Wales Population Health Survey and was completed by a representative sample of 2,081 respondents in early 2007. Responses were weighted against the New South Wales population.</p> <p>Results</p> <p>Multivariate analyses indicated that those with no formal educational qualifications were significantly more likely (OR = 2.10, 95%CI:1.32–3.35, p < 0.001) to think that a terrorist attack is very or extremely likely to occur in Australia and also more likely (OR = 3.62, 95%CI:2.25–5.83, p < 0.001) to be very or extremely concerned that they or a family member would be directly affected, compared to those with a university-level qualification. Speaking a language other than English at home predicted high concern (very/extremely) that self or family would be directly affected (OR = 3.02, 95%CI:2.02–4.53, p < 0.001) and was the strongest predictor of having made associated changes in living (OR = 3.27, 95%CI:2.17–4.93, p < 0.001). Being female predicted willingness to evacuate from public facilities. Speaking a language other than English at home predicted low willingness to evacuate.</p> <p>Conclusion</p> <p>Low education level is a risk factor for high terrorism risk perception and concerns regarding potential impacts. The pattern of concern and response among those of migrant background may reflect secondary social impacts associated with heightened community threat, rather than the direct threat of terrorism itself. These findings highlight the need for terrorism risk communication and related strategies to address the specific concerns of these sub-groups as a critical underpinning of population-level preparedness.</p

    CHILD: a new tool for detecting low-abundance insertions and deletions in standard sequence traces

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    Several methods have been proposed for detecting insertion/deletions (indels) from chromatograms generated by Sanger sequencing. However, most such methods are unsuitable when the mutated and normal variants occur at unequal ratios, such as is expected to be the case in cancer, with organellar DNA or with alternatively spliced RNAs. In addition, the current methods do not provide robust estimates of the statistical confidence of their results, and the sensitivity of this approach has not been rigorously evaluated. Here, we present CHILD, a tool specifically designed for indel detection in mixtures where one variant is rare. CHILD makes use of standard sequence alignment statistics to evaluate the significance of the results. The sensitivity of CHILD was tested by sequencing controlled mixtures of deleted and undeleted plasmids at various ratios. Our results indicate that CHILD can identify deleted molecules present as just 5% of the mixture. Notably, the results were plasmid/primer-specific; for some primers and/or plasmids, the deleted molecule was only detected when it comprised 10% or more of the mixture. The false positive rate was estimated to be lower than 0.4%. CHILD was implemented as a user-oriented web site, providing a sensitive and experimentally validated method for the detection of rare indel-carrying molecules in common Sanger sequence reads
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