Energy Efficiency and Performance in Multiprocessors Systems on Chip

As process technology shrinks, the transistor count on CPUs has increased. The breakdown of Dennard scaling has led to diminishing returns in terms of performance per power. A trend which promises to impact future CPU designs. This breakdown is due in part to the increase in transistor leakage driven static power. We, now, have constrained energy and power budgets. Thus, energy consumption has to be justified by an increased in performance. Simultaneously, architects have shifted to chip multiprocessors(CMPs) designs with large shared last level cache(LLC) to mitigate the cost of long latency off-chip memory access. A primary reason for that shift is the power efficiency of CMPs. Additionally, technology scaling has allowed the integration of platform components on the chip; a design referred to as multiprocessors system on chip (MpSoC). This integration improves the system performance as the communication latency between the components is reduced. Memory subsystems are essential to CPUs performance. Larger caches provide the CPU faster access to a larger data set. Consequently, the size of last level caches have increased to become a significant leakage power dissipation source. We propose a technique to facilitate power gating a partition of the LLC by migrating the high temporal blocks to a live partition; Thus reducing the performance impact. Given the high latency of memory subsystems, prefetching improves CPU performance by speculating future memory accesses and requesting the data ahead of the demand. In the context of CMPs running multiple concurrent processes, prefetching accuracy is critical to prevent cache pollution effects. Furthermore, given the current constraint energy environment, there is a need for lightweight prefetchers with high accuracy. To this end, we present BFetch a lightweight and accurate prefetcher driven by control flow predictions and effective address speculation. MpSoCs have mostly been used in mobile devices. The energy constraint is more pronounced in MpSoCs-based, battery powered mobile devices. The need to address the energy consumption in MpSoCs is further accentuated by the proliferation of mobile devices. This dissertation presents a framework to optimize the energy in MpSoCs. The proposed framework minimizes the energy consumption while meeting performance and power budgets constraints. We first apply this framework to the CPU then extend it to accommodate the GPU

COMPARING INFLUENZA POSITIVITY RATES BY REAL-TIME RT-PCR, ELISA AND VIRAL CULTURE METHODS IN CÔTE D’IVOIRE, WEST AFRICA, IN 2009

Detection of circulating influenza strains is a key public health concern especially in limited-resource settings where diagnosis capabilities remain a challenge. As part of multi-site surveillance in Côte d’Ivoire during the 2009 influenza A(H1N1) pandemic, we had the opportunity to test respiratory specimens collected from patients with acute respiratory illness (ARI). We analyzed and compared the percentage of specimens testing positive using three laboratory methods (rtRT-PCR, ELISA, viral culture). From January to October 2009, 1,356 respiratory specimens were collected from patients with acute respiratory illness and shipped at the WHO NIC (Institut Pasteur) Cote d’Ivoire, and 453 (33%) tested positive for influenza by one or more laboratory methods. The proportion of positive influenza tests did not differ by the sex or age of the patient or presenting symptoms, but did differ depending on the timing and site of specimen collection. Of the 453 positive specimens, 424 (93.6%) were detected by PCR, 199 (43.9%) by ELISA and 40 (8.8%) by viral culture. While seasonal influenza A(H1N1) virus strains were prominent, only four 2009 pandemic influenza A(H1N1) cases were detected. Use of molecular biology method (rtRT-PCR) increased sensitivity and diagnosis capabilities. Among all three methods used, rRT-PCR was the most sensitive and rapid method. More capacity building is still required for viral culture. Need to collect denominator data in order to have an accurate estimate of the burden of influenza. There was delayed introduction of pandemic influenza A(H1N1)2009 in Cote d’Ivoir

DETECTION OF NON-INFLUENZA VIRUSES IN ACUTE RESPIRATORY INFECTIONS IN CHILDREN UNDER FIVE-YEAR-OLD IN COTE D’IVOIRE (JANUARY – DECEMBER 2013)

Background: Influenza sentinel surveillance in Cote d’Ivoire showed that 70% of Acute Respiratory Infections (ARI) cases remained without etiology. This work aims to describe the epidemiological, clinical, and virological pattern of ARI that tested negative for influenza virus, in children under five years old. Materials and Methods: one thousand and fifty nine samples of patients presenting influenza Like Illness (ILI) or Severe Acute Respiratory Infections (SARI) symptoms were tested for other respiratory viruses using multiplex RTPCR assays targeting 10 respiratory viruses. Results: The following pathogens were detected as follows, hRV 31,92% (98/307), hRSV 24.4% (75/329), PIV 20.5% (63/307), HCoV 229E 12,05% (37/307), hMPV 6.2% (19/307), HCoVOC43 1.0% (3/307) and EnV 1.0% (3/307). Among the 1,059 specimens analyzed, 917 (86.6%) were ILI samples and 142 (23.4%) were SARI samples. The proportion of children infected with at least one virus was 29.8% (273/917) in ILI cases and 23.9% (34/142) in SARI cases. The most prevalent viruses, responsible for ILI cases were hRV with 35.89% (98/273) and hRSV in SARI cases with 41.2% (14/34) of cases. Among the 1,059 patients, only 22 (2.1%) children presented risk factors related to the severity of influenza virus infection. Conclusion: This study showed that respiratory viruses play an important role in the etiology of ARI in children. For a better understanding of the epidemiology of ARI and improved case management, it would be interesting in this context to expand the surveillance of influenza to other respiratory viruses

INVESTIGATION OF AN OUTBREAK OF ACUTE RESPIRATORY DISEASE IN CÔTE D’IVOIRE IN APRIL 2007

Background: This study aim was to investigate an outbreak of human cases of unexplained influenza-like illness and fatal acute respiratory infection (ARI), with simultaneous poultry illness and high mortality raising concerns of possible influenza A (H5N1), virus in Cote d’Ivoire in February and March 2007. Materials and Methods: To investigate the outbreak, we conducted active surveillance in the community and reviewed health registries. Persons meeting the case definition were asked to provide nasopharyngeal specimens. On the basis of clinical and epidemiological information, specimens were tested using conventional RT-PCR for the M gene of the influenza viruses and hemagglutinin H5 of avian influenza A (H5N1), virus; negative samples were tested for other respiratory viruses. Specimens from healthy animals were also collected. Results: Between October 2006, and February 2007, 104 suspected cases of Acute Respiratory Disease that included; 31 deaths recorded. We collected and tested 73 nasopharyngeal specimens; of which, 2, were positive for human Coronavirus OC43 and 1 for influenza C virus. No pathogens were identified in animal specimens. Conclusions: The investigation quickly ruled out influenza A (H5N1), virus as the cause and found laboratory-confirmed cases of influenza C virus and human Coronavirus OC 43 for the first time in both Côte d’Ivoire and in a Sub-Saharan African country. However we were not able to show that these viruses caused the outbreak. Monitoring of influenza viruses must be a priority but other respiratory viruses and non-viral causes may be of interest too

The evolving SARS-CoV-2 epidemic in Africa: Insights from rapidly expanding genomic surveillance.

Investment in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) sequencing in Africa over the past year has led to a major increase in the number of sequences that have been generated and used to track the pandemic on the continent, a number that now exceeds 100,000 genomes. Our results show an increase in the number of African countries that are able to sequence domestically and highlight that local sequencing enables faster turnaround times and more-regular routine surveillance. Despite limitations of low testing proportions, findings from this genomic surveillance study underscore the heterogeneous nature of the pandemic and illuminate the distinct dispersal dynamics of variants of concern-particularly Alpha, Beta, Delta, and Omicron-on the continent. Sustained investment for diagnostics and genomic surveillance in Africa is needed as the virus continues to evolve while the continent faces many emerging and reemerging infectious disease threats. These investments are crucial for pandemic preparedness and response and will serve the health of the continent well into the 21st century

The evolving SARS-CoV-2 epidemic in Africa: Insights from rapidly expanding genomic surveillance

INTRODUCTION Investment in Africa over the past year with regard to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) sequencing has led to a massive increase in the number of sequences, which, to date, exceeds 100,000 sequences generated to track the pandemic on the continent. These sequences have profoundly affected how public health officials in Africa have navigated the COVID-19 pandemic. RATIONALE We demonstrate how the first 100,000 SARS-CoV-2 sequences from Africa have helped monitor the epidemic on the continent, how genomic surveillance expanded over the course of the pandemic, and how we adapted our sequencing methods to deal with an evolving virus. Finally, we also examine how viral lineages have spread across the continent in a phylogeographic framework to gain insights into the underlying temporal and spatial transmission dynamics for several variants of concern (VOCs). RESULTS Our results indicate that the number of countries in Africa that can sequence the virus within their own borders is growing and that this is coupled with a shorter turnaround time from the time of sampling to sequence submission. Ongoing evolution necessitated the continual updating of primer sets, and, as a result, eight primer sets were designed in tandem with viral evolution and used to ensure effective sequencing of the virus. The pandemic unfolded through multiple waves of infection that were each driven by distinct genetic lineages, with B.1-like ancestral strains associated with the first pandemic wave of infections in 2020. Successive waves on the continent were fueled by different VOCs, with Alpha and Beta cocirculating in distinct spatial patterns during the second wave and Delta and Omicron affecting the whole continent during the third and fourth waves, respectively. Phylogeographic reconstruction points toward distinct differences in viral importation and exportation patterns associated with the Alpha, Beta, Delta, and Omicron variants and subvariants, when considering both Africa versus the rest of the world and viral dissemination within the continent. Our epidemiological and phylogenetic inferences therefore underscore the heterogeneous nature of the pandemic on the continent and highlight key insights and challenges, for instance, recognizing the limitations of low testing proportions. We also highlight the early warning capacity that genomic surveillance in Africa has had for the rest of the world with the detection of new lineages and variants, the most recent being the characterization of various Omicron subvariants. CONCLUSION Sustained investment for diagnostics and genomic surveillance in Africa is needed as the virus continues to evolve. This is important not only to help combat SARS-CoV-2 on the continent but also because it can be used as a platform to help address the many emerging and reemerging infectious disease threats in Africa. In particular, capacity building for local sequencing within countries or within the continent should be prioritized because this is generally associated with shorter turnaround times, providing the most benefit to local public health authorities tasked with pandemic response and mitigation and allowing for the fastest reaction to localized outbreaks. These investments are crucial for pandemic preparedness and response and will serve the health of the continent well into the 21st century

Recognition of partially occluded objects using fuzzy logic

This thesis presents a model-based fuzzy system for the recognition of partially occluded objects. The proposed system consists of two subsystems: a feature extraction and a fuzzy inference system. The first part consists of the thresholding, boundary extraction, gaussian smoothing and the polygonal approximation processes. Local dominant points extracted from the polygonal approximation of the objects contour boundary are used to build characterizing objects features. These features, which are the internal angle and the length ratio, are invariant to rotation scale and translation. An off-line knowledge base of model objects is first built using the described above subsystem. The fuzzy inference system evaluates the compatibility between the candidate and the model objects based on a matching criteria. This matching criteria evaluates the closeness between the candidate and the model objects features using fuzzy terms such as: very small, small, medium and large. The similarity between model and candidate object is expressed using fuzzy terms such as: not similar, not quiet similar and not similar. The system is tested for the recognition of objects comprising composite scenes of industrial parts such as pliers, wrenches and promising results were obtained. The performance is expressed by a controllable relative matching rate that compares the number of 3 or more consecutive matching points to the number of points in the model objects

The Diagnostic Accuracy and Clinimetric Properties of Screening Instruments to Identify Frail Older Adults Attending Emergency Departments: A Protocol for a Mixed Methods Systematic Review and Meta-Analysis

Background: Prompt and efficient identification and stratification of patients who are frail is important, as this cohort are at high risk of adverse healthcare outcomes. Numerous frailty screening tools have been developed to support their identification across different settings, yet relatively few have emerged for use in emergency departments (EDs). This protocol provides details for a systematic review aiming to synthesize the accumulated evidence regarding the diagnostic accuracy and clinimetric properties of frailty screening instruments to identify frail older adults in EDs. Methods: Six electronic databases will be searched from January 2000 to March 2021. Eligible studies will include adults aged ≥60 years screened in EDs with any available screening instrument to identify frailty (even if not originally designed for this purpose). Studies, including case-control, longitudinal, and cohort studies, will be included, where instruments are compared to a reference standard to explore diagnostic accuracy. Predictive accuracy for a selection of outcomes, including mortality, institutionalization, and readmission, will be assessed. Clinical and methodological heterogeneity will be examined, and a random effects meta-analysis performed if appropriate. Conclusion: Understanding whether frailty screening on presentation to EDs is accurate in identifying frailty, and predicting these outcomes is important for decision-making and targeting appropriate management

Fatal Case of Lassa Fever, Bangolo District, Côte d’Ivoire, 2015

International audienceLassa fever has not been reported in Côte d'Ivoire. We performed a retrospective analysis of human serum samples collected in Côte d'Ivoire in the dry seasons (January-April) during 2015-2018. We identified a fatal human case of Lassa fever in the Bangolo District of western Côte d'Ivoire during 2015