38 research outputs found

    A Methodology for Reliable Detection of Anomalous Behavior in Smartphones

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    Smartphones have become the most preferred computing device for both personal and business use. Different applications in smartphones result in different power consumption patterns. The fact that every application has been coded to perform different tasks leads to the claim that every action onboard (whether software or hardware) will consequently have a trace in the power consumption of the smartphone. When the same sequence of steps is repeated on it, it is observed that the power consumption patterns hold some degree of similarity. A device infected with malware can exhibit increased CPU usage, lower speeds, strange behavior such as e-mails or messages being sent automatically and without the user's knowledge; and programs or malware running intermittently or in cycles in the background. This deviation from the expected behavior of the device is termed an anomalous behavior and results in a reduction in the similarity of the power consumption. The anomalous behavior could also be due to gradual degradation of the device or change in the execution environment in addition to the presence of malware. The change in similarity can be used to detect the presence of anomalous behavior on smartphones. This thesis focuses on the detection of anomalous behavior from the power signatures of the smartphone. We have conducted experiments to measure and analyze the power consumption pattern of various smartphone apps. The test bench used for the experiments has a Monsoon Power Meter, which supplies power to the smartphone, and an external laptop collects the power samples from the meter. To emulate the presence of anomalous behavior, we developed an app which runs in the background with varying activity windows. Based on our experiments and analysis, we have developed two separate models for reliable detection of anomalous behavior from power signatures of the smartphone. The first model is based on Independent Component Analysis (ICA) and the second model is based on a Similarity Matrix developed using an array of low pass filters. These models detect the presence of anomalies by comparing the current power consumption pattern of the device under test with that of its normal behavior

    Genomic characteristics and clinical effect of the emergent SARS-CoV-2 B.1.1.7 lineage in London, UK: a whole-genome sequencing and hospital-based cohort study

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    BACKGROUND: Emergence of variants with specific mutations in key epitopes in the spike protein of SARS-CoV-2 raises concerns pertinent to mass vaccination campaigns and use of monoclonal antibodies. We aimed to describe the emergence of the B.1.1.7 variant of concern (VOC), including virological characteristics and clinical severity in contemporaneous patients with and without the variant. METHODS: In this cohort study, samples positive for SARS-CoV-2 on PCR that were collected from Nov 9, 2020, for patients acutely admitted to one of two hospitals on or before Dec 20, 2020, in London, UK, were sequenced and analysed for the presence of VOC-defining mutations. We fitted Poisson regression models to investigate the association between B.1.1.7 infection and severe disease (defined as point 6 or higher on the WHO ordinal scale within 14 days of symptoms or positive test) and death within 28 days of a positive test and did supplementary genomic analyses in a cohort of chronically shedding patients and in a cohort of remdesivir-treated patients. Viral load was compared by proxy, using PCR cycle threshold values and sequencing read depths. FINDINGS: Of 496 patients with samples positive for SARS-CoV-2 on PCR and who met inclusion criteria, 341 had samples that could be sequenced. 198 (58%) of 341 had B.1.1.7 infection and 143 (42%) had non-B.1.1.7 infection. We found no evidence of an association between severe disease and death and lineage (B.1.1.7 vs non-B.1.1.7) in unadjusted analyses (prevalence ratio [PR] 0·97 [95% CI 0·72-1·31]), or in analyses adjusted for hospital, sex, age, comorbidities, and ethnicity (adjusted PR 1·02 [0·76-1·38]). We detected no B.1.1.7 VOC-defining mutations in 123 chronically shedding immunocompromised patients or in 32 remdesivir-treated patients. Viral load by proxy was higher in B.1.1.7 samples than in non-B.1.1.7 samples, as measured by cycle threshold value (mean 28·8 [SD 4·7] vs 32·0 [4·8]; p=0·0085) and genomic read depth (1280 [1004] vs 831 [682]; p=0·0011). INTERPRETATION: Emerging evidence exists of increased transmissibility of B.1.1.7, and we found increased virus load by proxy for B.1.1.7 in our data. We did not identify an association of the variant with severe disease in this hospitalised cohort. FUNDING: University College London Hospitals NHS Trust, University College London/University College London Hospitals NIHR Biomedical Research Centre, Engineering and Physical Sciences Research Council

    Biofuels and thermal barrier:a review on compression ignition engine performance, combustion and exhaust gas emission

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    The performance of an internal combustion engine is affected when renewable biofuels are used instead of fossil fuels in an unmodified engine. Various engine modifications were experimented by the researchers to optimise the biofuels operated engine performance. Thermal barrier coating is one of the techniques used to improve the biofuels operated engine performance and combustion characteristics by reducing the heat loss from the combustion chamber. In this study, engine tests results on performance, combustion and exhaust emission characteristics of the biofuels operated thermal barrier coated engines were collated and reviewed. The results found in the literature were reviewed in three scenarios: (i) uncoated versus coated engine for fossil diesel fuel application, (ii) uncoated versus coated engine for biofuels (and blends) application, and (iii) fossil diesel use on uncoated engine versus biofuel (and blends) use on coated engine. Effects of injection timing, injection pressure and fuel properties on thermal barrier coatings were also discussed. The material type, thickness and properties of the coating materials used by the research community were presented. The effectiveness and durability of the coating layer depends on two key properties: low thermal conductivity and high thermal expansion coefficient. The current study showed that thermal barrier coatings could potentially offset the performance drop due to use of biofuels in the compression ignition engines. Improvements of up to 4.6% in torque, 7.8% in power output, 13.4% in brake specific fuel consumption, 15.4% in brake specific energy consumption and 10.7% in brake thermal efficiency were reported when biofuels or biofuel blends were used in the thermal barrier coated engines as compared to the uncoated engines. In coated engines, peak cylinder pressure and exhaust gas temperature were increased by up to 16.3 bar and 14% respectively as compared to uncoated condition. However, changes in the heat release rates were reported to be between −27% and +13.8% as compared to uncoated standard engine. Reductions of CO, CO2, HC and smoke emissions were reported by up to 3.8%, 11.1%, 90.9% and 63% respectively as compared to uncoated engines. Significant decreases in the PM emissions were also reported due to use of thermal barrier coatings in the combustion chamber. In contrast, at high speed and at high load operation, increase in the CO and CO2 emissions were also reported in coated engines. Coated engines gave higher NOx emissions by about 4–62.9% as compared to uncoated engines. Combined effects of thermal barrier coatings and optimisation of fuel properties and injection parameters produced further performance and emissions advantages compared to only thermal barrier coated engines. Overall, current review study showed that application of thermal barrier coatings in compression ignition engines could be beneficial when biofuels or biofuel blends are used instead of standard fossil diesel. However, more research is needed combining coatings, types of biofuels and other engine modifications to establish a concrete conclusion on the effectiveness of the thermal barrier when biofuels are used in the compression ignition engine. Reduction of NOx emissions is another important R & D area

    Method of Maximum Likelihood for Stationary Time Series Models

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    Whittle [1] proposed a method of obtaining the likelihood function for a linear dynamic model (with rational pulse transfer function and excited by Gaussian signal). In this note a simple derivation of his result is given

    OPTIMIZATION OF ALKALINE PROTEASE PRODUCTION FROM BACILLUS SP.AGT UNDER SOLID STATE FERMENTATION

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    ARTICLE INFO ABSTRACT Bacillus sp. AGT which produces an alkaline protease enzyme was isolated from the tannery effluent. It is important to produce the protease enzyme in inexpensive and use of cheaper raw material will slash the total production cost drastically. Production of alkaline protease by Bacillus sp.AGT using solid state fermentation was optimized. The effect of various substrates like green gram, rice bran and black gram were examined and found that green gram showed highest enzyme production. In addition to identification of suitable substrate, optimization of various process parameters such as inoculum concentration and initial moisture content were performed. Optimum inoculum size and initial moisture content were found to be 25% and 30% respectively

    Nephroprotective role of Potentilla reptans L. aqueous extract on paracetamol - induced kidney nephrotoxicity in male mice

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    Nephroprotective effects (NPE) of simple Potentilla reptans - aqueous leaf extract (Pr-ALE) leaves on Paracetamol induced kidney poisonousness in wistar rats. Adult male wistar rats (weight range (WR): 200-220g) were divided into 6 groups (n=6). Paracetamol (PA) and Silymarin (SY) stayed managed intraperitoneally arranged the 5th day to rats in all groups but the normal control. Furthermore, a significant nephroprotective (NP) of the aqueous leaf extract (ALE) and oral dose of PA and SY. Pr-ALE did not mortality or significant changes in the body weight. Progression of nephrotoxicity (NT) induced by PA in rats was interfered by Pr-ALE managed, and these effects were correspond to those managed with SY. This is the first record on NPE of Pr against PA-induced NT
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