Flexible Spare Core Placement in Torus Topology based NoCs and its validation on an FPGA

In the nano-scale era, Network-on-Chip (NoC) interconnection paradigm has gained importance to abide by the communication challenges in Chip Multi-Processors (CMPs). With increased integration density on CMPs, NoC components namely cores, routers, and links are susceptible to failures. Therefore, to improve system reliability, there is a need for efficient fault-tolerant techniques that mitigate permanent faults in NoC based CMPs. There exists several fault-tolerant techniques that address the permanent faults in application cores while placing the spare cores onto NoC topologies. However, these techniques are limited to Mesh topology based NoCs. There are few approaches that have realized the fault-tolerant solutions on an FPGA, but the study on architectural aspects of NoC is limited. This paper presents the flexible placement of spare core onto Torus topology-based NoC design by considering core faults and validating it on an FPGA. In the first phase, a mathematical formulation based on Integer Linear Programming (ILP) and meta-heuristic based Particle Swarm Optimization (PSO) have been proposed for the placement of spare core. In the second phase, we have implemented NoC router addressing scheme, routing algorithm, run-time fault injection model, and fault-tolerant placement of spare core onto Torus topology using an FPGA. Experiments have been done by taking different multimedia and synthetic application benchmarks. This has been done in both static and dynamic simulation environments followed by hardware implementation. In the static simulation environment, the experimentations are carried out by scaling the network size and router faults in the network. The results obtained from our approach outperform the methods such as Fault-tolerant Spare Core Mapping (FSCM), Simulated Annealing (SA), and Genetic Algorithm (GA) proposed in the literature. For the experiments carried out by scaling the network size, our proposed methodology shows an average improvement of 18.83%, 4.55%, 12.12% in communication cost over the approaches FSCM, SA, and GA, respectively. For the experiments carried out by scaling the router faults in the network, our approach shows an improvement of 34.27%, 26.26%, and 30.41% over the approaches FSCM, SA, and GA, respectively. For the dynamic simulations, our approach shows an average improvement of 5.67%, 0.44%, and 3.69%, over the approaches FSCM, SA, and GA, respectively. In the hardware implementation, our approach shows an average improvement of 5.38%, 7.45%, 27.10% in terms of application runtime over the approaches SA, GA, and FSCM, respectively. This shows the superiority of the proposed approach over the approaches presented in the literature.publishedVersio

Fault-Tolerant Application-Specific Topology based NoC and its Prototype on an FPGA

Application-Specific Networks-on-Chips (ASNoCs) are suitable communication platforms for meeting current application requirements. Interconnection links are the primary components involved in communication between the cores of an ASNoC design. The integration density in ASNoC increases with continuous scaling down of the transistor size. Excessive integration density in ASNoC can result in the formation of thermal hotspots, which can cause a system to fail permanently. As a result, fault-tolerant techniques are required to address the permanent faults in interconnection links of an ASNoC design. By taking into account link faults in the topology, this paper introduces a fault-tolerant application-specific topology-based NoC design and its prototype on an FPGA. To place spare links in the ASNoC topology, a meta-heuristic algorithm based on Particle Swarm Optimization (PSO) is proposed. By taking link faults into account in ASNoC design, we also propose an application mapping heuristic and a table-based fault-tolerant routing algorithm. Experiments are carried out for a specific link and any link fault in fault-tolerant topologies generated by our approach and approaches reported in the literature. For the experimentation, we used the multi-media applications Picture-in-Picture (PiP), Moving Pictures Expert Group (MPEG) - 4, MP3Encoder, and Video Object Plane Decoder (VOPD). Experiments are run on software and hardware platforms. The static performance metric communication cost and the dynamic performance metrics network latency, throughput, and router power consumption are examined using software platform. In the hardware platform, the Field Programmable Gate Array (FPGA) is used to validate proposed fault-tolerant topologies and analyze performance metrics such as application runtime, resource utilization, and power consumption. The results are compared with the existing approaches, specifically Ring topology and its modified versions on both software and hardware platforms. The experimental results obtained from software and hardware platforms for a specific link and any link fault show significant improvements in performance metrics using our approach when compared with the related works in the literature.publishedVersio

Is deep venous thrombosis a common complication in patients treated with Ilizarov external fixator?

Background: Determining the incidence of deep venous thrombosis (DVT), a prospective study, in patients treated with Ilizarov external fixators for lower extremity fractures, fracture non unions or deformity correction.Methods: A Prospective, observational and cross sectional study. 49 Patients with complex lower extremity injuries, deformities and non-union of fractures were treated with Ilizarov external fixator application, were assessed clinically and radiological (Venous Doppler) at regular intervals- 6 days post-surgery then at 6 weeks, 12 weeks and between 4 to 6 months post-operative. None were given chemoprophylaxis for the prevention of DVT and everyone were assessed pre operatively with a questionnaire and wells criteria was taken for assessment of high risk for developing venous thrombosis. There were 41 men and 8 women, 85.75% of the study group is of age 30 to 60 years.Results: Only 1 of 49 patients developed radiological evident DVT within 6 days of surgery. Patients who underwent application of Ilizarov external fixator electively for deformity correction, osteomyelitis and non-union showed no clinical or radiological evident signs of DVT.Conclusions: The incidence of DVT and PTE is minimal when patients without chemoprophylaxis underwent lower limb Ilizarov external fixator application for acute trauma and electively for deformity correction, treatment of non-union and osteomyelitis. However further comparative and randomized studies need to be done to confirm our results

The Static Failure of Adhesively Bonded Metal Laminate Structures: A Cohesive Zone Approach

Data on distribution, ecology, biomass, recruitment, growth, mortality and productivity of the West African bloody cockle Anadara senilis were collected at the Banc d'Aguuin, Mauritania, in early 1985 and 1986. Ash-free dry weight appeared to be correlated best with shell height. A. senilis was abundant on the tidal flats of landlocked coastal bays, but nearly absent on the tidal flats bordering the open sea. The average biomass for the entire area of tidal flats was estimated at 5.5 g·m−2 ash-free dry weight. The A. senilis population appeared to consist mainly of 10 to 20-year-old individuals, showing a very slow growth and a production: biomass ratio of about 0.02 y−1. Recruitment appeared negligible and mortality was estimated to be about 10% per year. Oystercatchers (Haematopus ostralegus), the gastropod Cymbium cymbium and unknown fish species were responsible for a large share of this. The distinction of annual growth marks permitted the assessment of year-class strength, which appeared to be correlated with the average discharge of the river Senegal. This may be explained by assuming that year-class strength and river discharge both are correlated with rainfall at the Banc d'Arguin.

Genetic Variability, Genotype × Environment Interaction, Correlation, and GGE Biplot Analysis for Grain Iron and Zinc Concentration and Other Agronomic Traits in RIL Population of Sorghum (Sorghum bicolor L. Moench)

The low grain iron and zinc densities are well documented problems in food crops, affecting crop nutritional quality especially in cereals. Sorghum is a major source of energy and micronutrients for majority of population in Africa and central India. Understanding genetic variation, genotype × environment interaction and association between these traits is critical for development of improved cultivars with high iron and zinc. A total of 336 sorghum RILs (Recombinant Inbred Lines) were evaluated for grain iron and zinc concentration along with other agronomic traits for 2 years at three locations. The results showed that large variability exists in RIL population for both micronutrients (Iron = 10.8 to 76.4 mg kg−1 and Zinc = 10.2 to 58.7 mg kg−1, across environments) and agronomic traits. Genotype × environment interaction for both micronutrients (iron and zinc) was highly significant. GGE biplots comparison for grain iron and zinc showed greater variation across environments. The results also showed that G × E was substantial for grain iron and zinc, hence wider testing needed for taking care of G × E interaction to breed micronutrient rich sorghum lines. Iron and zinc concentration showed high significant positive correlation (across environment = 0.79; p 0.60, in individual environments) for Fe and Zn and other traits studied indicating its suitability to map QTL for iron and zinc

Different Modes of Retrovirus Restriction by Human APOBEC3A and APOBEC3G In Vivo

The apolipoprotein B editing complex 3 (A3) cytidine deaminases are among the most highly evolutionarily selected retroviral restriction factors, both in terms of gene copy number and sequence diversity. Primate genomes encode seven A3 genes, and while A3F and 3G are widely recognized as important in the restriction of HIV, the role of the other genes, particularly A3A, is not as clear. Indeed, since human cells can express multiple A3 genes, and because of the lack of an experimentally tractable model, it is difficult to dissect the individual contribution of each gene to virus restriction in vivo. To overcome this problem, we generated human A3A and A3G transgenic mice on a mouse A3 knockout background. Using these mice, we demonstrate that both A3A and A3G restrict infection by murine retroviruses but by different mechanisms: A3G was packaged into virions and caused extensive deamination of the retrovirus genomes while A3A was not packaged and instead restricted infection when expressed in target cells. Additionally, we show that a murine leukemia virus engineered to express HIV Vif overcame the A3G-mediated restriction, thereby creating a novel model for studying the interaction between these proteins. We have thus developed an in vivo system for understanding how human A3 proteins use different modes of restriction, as well as a means for testing therapies that disrupt HIV Vif-A3G interactions.United States. Public Health Service (Grant R01-AI-085015)United States. Public Health Service (Grant T32-CA115299 )United States. Public Health Service (Grant F32-AI100512