Abstract: Brain functional networks based on resting-state EEG
data were compared between patients with mild Alzheimer’s disease
(mAD) and matched patients with amnestic subtype of mild cognitive
impairment (aMCI). We integrated the time–frequency cross mutual
information (TFCMI) method to estimate the EEG functional
connectivity between cortical regions and the network analysis based
on graph theory to further investigate the alterations of functional
networks in mAD compared with aMCI group. We aimed at
investigating the changes of network integrity, local clustering,
information processing efficiency, and fault tolerance in mAD brain
networks for different frequency bands based on several topological
properties, including degree, strength, clustering coefficient, shortest
path length, and efficiency. Results showed that the disruptions of
network integrity and reductions of network efficiency in mAD
characterized by lower degree, decreased clustering coefficient, higher
shortest path length, and reduced global and local efficiencies in the
delta, theta, beta2, and gamma bands were evident. The significant
changes in network organization can be used in assisting
discrimination of mAD from aMCI in clinical.
Abstract: A wireless sensor network (WSN) is a collection of
sensor nodes organized into a cooperative network. These nodes
communicate through a wireless antenna. Reduction in physical size
and multiband operation is an important requirement of WSN
antenna. Fractal antenna is used for miniaturization and multiband
operation. The self-similar or self-affine and space filling property of
fractal geometry increases the effective electrical length of the
antenna, reduces the size and make them frequency independent. This
paper elaborates on Dual band fractal antenna with Coplanar
Waveguide (CPW) feed for WSN. The proposed antenna is designed
on a FR4 substrate with the dimension of 27mm x 28.5mm x 1.6mm,
resonates at 2.4GHz and 5.2GHz with a return loss less than -10dB.
The design and simulation process is carried out using IE3D
simulation software. The simulated and measured results are found in
good agreement.
Abstract: The majority of contemporary insulation materials
commonly used in the building industry is made from non-renewable
raw materials; furthermore, their production often brings high energy
costs. A long-term trend as far as sustainable development is
concerned has been the reduction of energy and material demands of
building material production. One of the solutions is the possibility of
using easily renewable natural raw material sources which are
considerably more ecological and their production is mostly less
energy-consuming compared to the production of normal insulations
(mineral wool, polystyrene). The paper describes the results of
research focused on the development of thermal and acoustic
insulation materials based on natural fibres intended for floor
constructions. Given the characteristic open porosity of natural fibre
materials, the hygrothermal behaviour of the developed materials was
studied. Especially the influence of relative humidity and temperature
on thermal insulation properties was observed.
Abstract: Metal-enhanced Luminescence of silicon nanocrystals
(SiNCs) was determined using two different particle sizes of silver
nanoparticles (AgNPs). SiNCs have been characterized by scanning
electron microscopy (SEM), high resolution transmission electron
microscopy (HRTEM), Fourier transform infrared spectroscopy
(FTIR) and X-ray photoelectron spectroscopy (XPS). It is found that
the SiNCs are crystalline with an average diameter of 65 nm and FCC
lattice. AgNPs were synthesized using photochemical reduction of
AgNO3 with sodium dodecyl sulphate (SDS). The enhanced
luminescence of SiNCs by AgNPs was evaluated by confocal Raman
microspectroscopy. Enhancement up to x9 and x3 times were
observed for SiNCs that mixed with AgNPs which have an average
particle size of 100 nm and 30 nm, respectively. Silver NPs-enhanced
luminescence of SiNCs occurs as a result of the coupling between the
excitation laser light and the plasmon bands of AgNPs; thus this
intense field at AgNPs surface couples strongly to SiNCs.
Abstract: Copper being one of the major intrinsic residual
impurities in steel possesses the tendency to induce severe
microstructural distortions if not controlled within certain limits.
Hence, this paper investigates the effect of this element on the
mechanical properties of construction steel with a view to ascertain
its safe limits for effective control. The experiment entails collection
of statistically scheduled samples of hot rolled profiles with varied
copper concentrations in the range of 0.12-0.39 wt. %. From these
samples were prepared standard test specimens subjected to tensile,
impact, hardness and microstructural analyses. Results show a rather
huge compromise in mechanical properties as the specimens
demonstrated 54.3%, 74.2% and 64.9% reduction in tensile strength,
impact energy and hardness respectively as copper content increases
from 0.12 wt. % to 0.39 wt. %. The steel’s abysmal performance is
due to the severe distortion of the microstructure occasioned by the
development of incoherent complex compounds which weaken the
pearlite reinforcing phase. It is concluded that the presence of copper
above 0.22 wt. % is deleterious to construction steel performance.
Abstract: Economic Dispatch (ED) is one of the most
challenging problems of power system since it is difficult to determine
the optimum generation scheduling to meet the particular load demand
with the minimum fuel costs while all constraints are satisfied. The
objective of the Economic Dispatch Problems (EDPs) of electric
power generation is to schedule the committed generating units
outputs so as to meet the required load demand at minimum operating
cost while satisfying all units and system equality and inequality
constraints. In this paper, an efficient and practical steady-state genetic
algorithm (SSGAs) has been proposed for solving the economic
dispatch problem. The objective is to minimize the total generation
fuel cost and keep the power flows within the security limits. To
achieve that, the present work is developed to determine the optimal
location and size of capacitors in transmission power system where,
the Participation Factor Algorithm and the Steady State Genetic
Algorithm are proposed to select the best locations for the capacitors
and determine the optimal size for them.
Abstract: This paper addresses the reduction of peak to average
power ratio (PAPR) for the OFDM in Mobile-WiMAX physical layer
(PHY) standard. In the process, the best achievable PAPR of 0 dB is
found for the OFDM spectrum using phase modulation technique
which avoids the nonlinear distortion. The performance of the
WiMAX PHY standard is handled by the software defined radio
(SDR) prototype in which GNU Radio and USRP N210 employed as
software and hardware platforms respectively. It is also found that
BER performance is shown for different coding and different
modulation schemes. To empathize wireless propagation in specific
environments, a sliding correlator wireless channel sounding system
is designed by using SDR testbed.
Abstract: The reduction of greenhouse gases emissions is highly
discussed ecological theme at present. In addition to power industry
also main production sectors of binders, i.e. cement, air and hydraulic
lime are very sensitive to these questions. One of the possibilities
how CO2 emissions can be reduced directly at clinker burnout is
represented by partial substitution of lime with a material containing
limy ions at absence of carbonate group. Fluidised fly ash is one of
such potential raw materials where CaO can be found free and also
bound in anhydrite, CaSO4. At application of FBC (fluidized bed
combustion) fly ash with approximate 20% CaO content and its
dosing ratio to high percent lime 1:2, corresponding stechiometrically
to the preparation of raw material powder, approximately 0,37 t CO2
per 1 ton of one-component cement would be released at clinker
burnout compared to 0,46 t CO2 when orthodox raw materials are
used. The reduction of CO2 emissions thus could reach even 20%.
Abstract: Frequent pattern mining is the process of finding a
pattern (a set of items, subsequences, substructures, etc.) that occurs
frequently in a data set. It was proposed in the context of frequent
itemsets and association rule mining. Frequent pattern mining is used
to find inherent regularities in data. What products were often
purchased together? Its applications include basket data analysis,
cross-marketing, catalog design, sale campaign analysis, Web log
(click stream) analysis, and DNA sequence analysis. However, one of
the bottlenecks of frequent itemset mining is that as the data increase
the amount of time and resources required to mining the data
increases at an exponential rate. In this investigation a new algorithm
is proposed which can be uses as a pre-processor for frequent itemset
mining. FASTER (FeAture SelecTion using Entropy and Rough sets)
is a hybrid pre-processor algorithm which utilizes entropy and roughsets
to carry out record reduction and feature (attribute) selection
respectively. FASTER for frequent itemset mining can produce a
speed up of 3.1 times when compared to original algorithm while
maintaining an accuracy of 71%.
Abstract: In many communication and signal processing
systems, it is highly desirable to implement an efficient narrow-band
filter that decimate or interpolate the incoming signals. This paper
presents hardware efficient compensated CIC filter over a narrow
band frequency that increases the speed of down sampling by using
multiplierless decimation filters with polyphase FIR filter structure.
The proposed work analyzed the performance of compensated CIC
filter on the bases of the improvement of frequency response with
reduced hardware complexity in terms of no. of adders and
multipliers and produces the filtered results without any alterations.
CIC compensator filter demonstrated that by using compensation
with CIC filter improve the frequency response in passed of interest
26.57% with the reduction in hardware complexity 12.25%
multiplications per input sample (MPIS) and 23.4% additions per
input sample (APIS) w.r.t. FIR filter respectively.
Abstract: In this paper the issue of dimensionality reduction is
investigated in finger vein recognition systems using kernel Principal
Component Analysis (KPCA). One aspect of KPCA is to find the
most appropriate kernel function on finger vein recognition as there
are several kernel functions which can be used within PCA-based
algorithms. In this paper, however, another side of PCA-based
algorithms -particularly KPCA- is investigated. The aspect of
dimension of feature vector in PCA-based algorithms is of
importance especially when it comes to the real-world applications
and usage of such algorithms. It means that a fixed dimension of
feature vector has to be set to reduce the dimension of the input and
output data and extract the features from them. Then a classifier is
performed to classify the data and make the final decision. We
analyze KPCA (Polynomial, Gaussian, and Laplacian) in details in
this paper and investigate the optimal feature extraction dimension in
finger vein recognition using KPCA.
Abstract: The high Peak to Average Power Ratio (PAR) in Filter
Bank Multicarrier with Offset Quadrature Amplitude Modulation
(FBMC-OQAM) can significantly reduce power efficiency and
performance. In this paper, we address the problem of PAPR
reduction for FBMC-OQAM systems using Tone Reservation (TR)
technique. Due to the overlapping structure of FBMCOQAM signals,
directly applying TR schemes of OFDM systems to FBMC-OQAM
systems is not effective. We improve the tone reservation (TR)
technique by employing sliding window with Active Constellation
Extension for the PAPR reduction of FBMC-OQAM signals, called
sliding window tone reservation Active Constellation Extension
(SW-TRACE) technique. The proposed SW-TRACE technique uses
the peak reduction tones (PRTs) of several consecutive data
blocks to cancel the peaks of the FBMC-OQAM signal inside a
window, with dynamically extending outer constellation points in
active(data-carrying) channels, within margin-preserving constraints,
in order to minimize the peak magnitude. Analysis and simulation
results compared to the existing Tone Reservation (TR) technique for
FBMC/OQAM system. The proposed method SW-TRACE has better
PAPR performance and lower computational complexity.
Abstract: Because of high thermal efficiency and low CO2
emission, diesel engines are being used widely in many industrial
fields although it makes many PM and NOx which give both human
health and environment a negative effect. NOx regulations for diesel
engines, however, are being strengthened and it is impossible to meet
the emission standard without NOx reduction devices such as SCR
(Selective Catalytic Reduction), LNC (Lean NOx Catalyst), and LNT
(Lean NOx Trap). Among the NOx reduction devices, urea-SCR
system is known as the most stable and efficient method to solve the
problem of NOx emission. But this device has some issues associated
with the ammonia slip phenomenon which is occurred by shortage of
evaporation and thermolysis time, and that makes it difficult to achieve
uniform distribution of the injected urea in front of monolith.
Therefore, this study has focused on the mixing enhancement between
urea and exhaust gases to enhance the efficiency of the SCR catalyst
equipped in catalytic muffler by changing inlet gas temperature and
spray conditions to improve the spray uniformity of the urea water
solution. Finally, it can be found that various parameters such as inlet
gas temperature and injector and injection angles significantly affect
the evaporation and mixing of the urea water solution with exhaust
gases, and therefore, optimization of these parameters are required.
Abstract: The present environmental issues have made aircraft jet noise reduction a crucial problem in aero-acoustics research. Acoustic studies reveal that addition of chevrons to the nozzle reduces the sound pressure level reasonably with acceptable reduction in performance. In this paper comprehensive numerical studies on acoustic characteristics of different types of chevron nozzles have been carried out with non-reacting flows for the shape optimization of chevrons in supersonic nozzles for aerospace applications. The numerical studies have been carried out using a validated steady 3D density based, k-ε turbulence model. In this paper chevron with sharp edge, flat edge, round edge and U-type edge are selected for the jet acoustic characterization of supersonic nozzles. We observed that compared to the base model a case with round-shaped chevron nozzle could reduce 4.13% acoustic level with 0.6% thrust loss. We concluded that the prudent selection of the chevron shape will enable an appreciable reduction of the aircraft jet noise without compromising its overall performance. It is evident from the present numerical simulations that k-ε model can predict reasonably well the acoustic level of chevron supersonic nozzles for its shape optimization.
Abstract: An optimisation method using both global and local
optimisation is implemented to determine the flapping profile which
will produce the most lift for an experimental wing-actuation system.
The optimisation method is tested using a numerical quasi-steady
analysis. Results of an optimised flapping profile show a 20% increase
in lift generated as compared to flapping profiles obtained by high
speed cinematography of a Sympetrum frequens dragonfly. Initial
optimisation procedures showed 3166 objective function evaluations.
The global optimisation parameters - initial sample size and stage
one sample size, were altered to reduce the number of function
evaluations. Altering the stage one sample size had no significant
effect. It was found that reducing the initial sample size to 400
would allow a reduction in computational effort to approximately
1500 function evaluations without compromising the global solvers
ability to locate potential minima. To further reduce the optimisation
effort required, we increase the local solver’s convergence tolerance
criterion. An increase in the tolerance from 0.02N to 0.05N decreased
the number of function evaluations by another 20%. However, this
potentially reduces the maximum obtainable lift by up to 0.025N.
Abstract: In recent years in Italy the progress of the automobile industry, in the field of reduction of emissions values, is very remarkable. Nevertheless their evaluation and reduction is a key problem, especially in the cities, that account for more than 50% of world population. In this paper we dealt with the problem of describing a quantitatively approach for the reconstruction of GPS coordinates and altitude, in the context of correlation study between driving cycles / emission / geographical location, during an experimental campaign realized with some instrumented cars.
Abstract: Chaotic analysis has been performed on the river flow time series before and after applying the wavelet based de-noising techniques in order to investigate the noise content effects on chaotic nature of flow series. In this study, 38 years of monthly runoff data of three gauging stations were used. Gauging stations were located in Ghar-e-Aghaj river basin, Fars province, Iran. Noise level of time series was estimated with the aid of Gaussian kernel algorithm. This step was found to be crucial in preventing removal of the vital data such as memory, correlation and trend from the time series in addition to the noise during de-noising process.
Abstract: Advances in the field of image processing envision a
new era of evaluation techniques and application of procedures in
various different fields. One such field being considered is the
biomedical field for prognosis as well as diagnosis of diseases. This
plethora of methods though provides a wide range of options to select
from, it also proves confusion in selecting the apt process and also in
finding which one is more suitable. Our objective is to use a series of
techniques on bone scans, so as to detect the occurrence of
rheumatoid arthritis (RA) as accurately as possible. Amongst other
techniques existing in the field our proposed system tends to be more
effective as it depends on new methodologies that have been proved
to be better and more consistent than others. Computer aided
diagnosis will provide more accurate and infallible rate of
consistency that will help to improve the efficiency of the system.
The image first undergoes histogram smoothing and specification,
morphing operation, boundary detection by edge following algorithm
and finally image subtraction to determine the presence of
rheumatoid arthritis in a more efficient and effective way. Using preprocessing
noises are removed from images and using segmentation,
region of interest is found and Histogram smoothing is applied for a
specific portion of the images. Gray level co-occurrence matrix
(GLCM) features like Mean, Median, Energy, Correlation, Bone
Mineral Density (BMD) and etc. After finding all the features it
stores in the database. This dataset is trained with inflamed and noninflamed
values and with the help of neural network all the new
images are checked properly for their status and Rough set is
implemented for further reduction.
Abstract: The use of biodiesel in conventional diesel engines results in substantial reduction of unburned hydrocarbon, carbon monoxide and particulate matters. The performance, emission and combustion characteristics of a single cylinder four stroke variable compression ratio engine when fueled with Karanja (Pongamia) methyl ester and its 10-50 % blends with diesel (on a volume basis) are investigated and compared with standard diesel. The suitability of karanja methyl ester as a biofuel has been established in this study. The useful brake power obtained is similar to diesel fuel for all loads. Experiment has been conducted at a fixed engine speed of 1500 rpm, variable load and at compression ratios of 17.5:1 and 18.5:1. The impact of compression ratio on fuel consumption, combustion pressures and exhaust gas emissions has been investigated and presented. Optimum compression ratio which gives best performance has been identified. The results indicate longer ignition delay, maximum rate of pressure rise, lower heat release rate and higher mass fraction burnt at higher compression ratio for pongamia oil methyl ester when compared to that of diesel. The brake thermal efficiency for pongamia oil methyl ester blends and diesel has been calculated and the blend B20 is found to give maximum thermal efficiency. The blends when used as fuel results in reduction of carbon monoxide, hydrocarbon and increase in nitrogen oxides emissions. PME as an oxygenated fuel generated more complete combustion, which means increased torque and power. This is also supported with higher thermal efficiencies of the PME blends. NOx is slightly increased due to the higher combustion temperature and the presence of fuel oxygen with the blend at full load. PME as a new Biodiesel and its blends can be used in diesel engines without any engine modification.
Abstract: In order to respond the human needs, all regional, social, and economical factors are available to gain residents’ comfort and ideal architecture. There is no doubt the thermal comfort has to satisfy people not only for daily and physical activities but also creating pleasant area for mental activities and relaxing. It costs energy and increases greenhouse gas emissions.
Reducing energy use in buildings is a critical component of meeting carbon reduction commitments. Hence housing design represents a major opportunity to cut energy use and CO2 emissions.
In terms of energy efficiency, it is vital to propose and research modern design methods for buildings however vernacular architecture techniques are proven empirical existing practices which have to be considered. This research tries to compare two architectural solution were proposed by Persian vernacular architecture, to achieve energy efficiency in hot areas.
The aim of this research is to analyze two forms of traditional Persian architecture in different locations in order to develop a systematic research and sustainable technologies on adaptation to contemporary living standards.