28,404 research outputs found
Combined Human, Antenna Orientation in Elevation Direction and Ground Effect on RSSI in Wireless Sensor Networks
In this paper, we experimentally investigate the combined effect of human,
antenna orientation in elevation direction and the ground effect on the
Received Signal Strength Indicator (RSSI) parameter in the Wireless Sensor
Network (WSN). In experiment, we use MICAz motes and consider different
scenarios where antenna of the transmitter node is tilted in elevation
direction. The motes were placed on the ground to take into account the ground
effect on the RSSI. The effect of one, two and four persons on the RSSI is
recorded. For one and two persons, different walking paces e.g. slow, medium
and fast pace, are analysed. However, in case of four persons, random movement
is carried out between the pair of motes. The experimental results show that
some antenna orientation angles have drastic effect on the RSSI, even without
any human activity. The fluctuation count and range of RSSI in different
scenarios with same walking pace are completely different. Therefore, an
efficient human activity algorithm is need that effectively takes into count
the antenna elevation and other parameters to accurately detect the human
activity in the WSN deployment region.Comment: 10th IEEE International Conference on Frontiers of Information
Technology (FIT 12), 201
Assessment of seismic performance of adobe structures in Pakistan and Portugal
Adobe buildings exist in different parts of the world. The construction of these buildings can be carried out
economically, using locally available materials and skills that do not require use of modern machinery.
Therefore, adobe buildings provide an economic housing option. The construction of adobe structures is carried
out based on traditional construction practices which vary from region to region. This paper presents the results
of a study which was conducted to study the construction practices of adobe buildings in Pakistan and Portugal
in the context of their seismic vulnerability. The adobe buildings in both these countries were found to be
subjected to seismic hazard levels which, although is low in some regions, may cause significant damages. Lack of essential elements or details for the adequate seismic performance was found in the adobe buildings in both regions
Kinetically driven helix formation during the homopolymer collapse process
Using Langevin simulations, we find that simple 'generic' bead-and-spring
homopolymer chains in a sufficiently bad solvent spontaneously develop helical
order during the process of collapsing from an initially stretched
conformation. The helix formation is initiated by the unstable modes of the
straight chain, which drive the system towards a long-lived metastable
transient state. The effect is most pronounced if hydrodynamic interactions are
screened.Comment: 4 pages, 4 figure
Monte Carlo simulation of the transmission of measles: Beyond the mass action principle
We present a Monte Carlo simulation of the transmission of measles within a
population sample during its growing and equilibrium states by introducing two
different vaccination schedules of one and two doses. We study the effects of
the contact rate per unit time as well as the initial conditions on the
persistence of the disease. We found a weak effect of the initial conditions
while the disease persists when lies in the range 1/L-10/L ( being
the latent period). Further comparison with existing data, prediction of future
epidemics and other estimations of the vaccination efficiency are provided.
Finally, we compare our approach to the models using the mass action
principle in the first and another epidemic region and found the incidence
independent of the number of susceptibles after the epidemic peak while it
strongly fluctuates in its growing region. This method can be easily applied to
other human, animals and vegetable diseases and includes more complicated
parameters.Comment: 15 pages, 4 figures, 1 table, Submitted to Phys.Rev.
Pyrrolizine-5-carboxamides: Exploring the impact of various substituents on the anti-inflammatory and anticancer activities
Towards optimization of the pyrrolizine-5-carboxamide scaffold, a novel series of six derivatives (4a-c and 5a-c) was prepared and evaluated for their anti-inflammatory, analgesic and anticancer activities. The (EZ)-7-cyano-6-((4-hydroxybenzylidene)amino)-N-(p-tolyl)-2,3-dihydro-1H-pyrrolizine-5-carboxamide (4b) and (EZ)-6-((4-chlorobenzylidene)-amino)-7-cyano-N-(p-tolyl)-2,3-dihydro-1H-pyrrolizine-5-carboxamide (5b) bearing the electron donating methyl group showed the highest anti-inflammatory activity while (EZ)-6-((4-chlorobenzylidene)amino)-7-cyano-N-phenyl-2,3-dihydro-1H-pyrrolizine-5-carboxamide (5a) was the most active analgesic agent. Cytotoxicity of the new compounds was evaluated against the MCF-7, A2780 and HT29 cancer cell lines using the MTT assay. Compounds 4b and 5b displayed high anticancer activity with IC50 in the range of 0.30–0.92 µmol L–1 against the three cell lines, while compound (EZ)-N-(4-chlorophenyl)-7-cyano-6-((4-hydroxybenzylidene)-amino)-2,3-dihydro-1H-pyrrolizine-5-carboxamide (4c) was the most active against MCF-7 cells (IC50 = 0.08 µmol L–1). Both the anti-inflammatory and anticancer activities of the new compounds were dependent on the type of substituent on the phenyl rings. Substituents with opposite electronic effects on the two phenyl rings are preferable for high cytotoxicity against the MCF-7 and A2780 cells. COX inhibition was suggested as the molecular mechanism of the anti-inflammatory activity of the new compounds while no clear relationship could be observed between COX inhibition and anticancer activity. Compound 5b, the most active against the three cell lines, induced dose-dependent early apoptosis with 0.1–0.2 % necrosis in MCF-7 cells. New compounds showed promising drug-likeness scores while the docking study revealed high binding affinity to COX-2. Taken together, this study highlighted the significant impact of the substituents on the anti-inflammatory and anticancer activity of pyrrolizine-5-carboxamides, which could help in further optimization to discover good leads for the treatment of cancer and inflammation
Machine Learning-Based Prediction of Compressive Performance in Circular Concrete Columns Confined with FRP
This article presents a comprehensive investigation, focusing on the prediction and formulation of the design equation of compressive strength of circular concrete columns confined with Fiber Reinforced Polymer (FRP) using advanced machine learning models. Through an extensive analysis of 170 experimental data specimens, the study examines the effects of six key parameters, including concrete cylinder diameter, concrete cylinder-FRP thickness, compressive strength of concrete without FRP, initial compressive strain of concrete without FRP, elastic modulus and tensile strength of FRP, on the compressive strength of the circular concrete columns confined with FRP. The predictive model and design equation of compressive strength is developed using a machine learning technique, specifically the artificial neural networks (ANN) model. The results demonstrates strong correlations between the compressive strength of the circular concrete columns confined with FRP and certain factors, such as the compressive strength of the concrete and compressive strain of the concrete column without FRP, elastic modulus of FRP, and tensile strength of FRP. The ANN model specifically developed using Neural Designer, exhibits superior predictive accuracy compared to other constitutive models, showcasing its potential for practical implementation. The study's findings contribute valuable insights into accurately predicting the compressive performance of circular concrete columns confined with FRP, which can aid in optimizing and designing civil engineering structures for enhanced performance and efficiency
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