Abstract: Wireless location is to determine the mobile station (MS) location in a wireless cellular communications system. When fewer base stations (BSs) may be available for location purposes or the measurements with large errors in non-line-of-sight (NLOS) environments, it is necessary to integrate all available heterogeneous measurements to achieve high location accuracy. This paper illustrates a hybrid proposed schemes that combine time of arrival (TOA) at three BSs and angle of arrival (AOA) information at the serving BS to give a location estimate of the MS. The proposed schemes mitigate the NLOS effect simply by the weighted sum of the intersections between three TOA circles and the AOA line without requiring a priori information about the NLOS error. Simulation results show that the proposed methods can achieve better accuracy when compare with Taylor series algorithm (TSA) and the hybrid lines of position algorithm (HLOP).
Abstract: A new, rapidly convergent, numerical procedure for
internal loading distribution computation in statically loaded, singlerow,
angular-contact ball bearings, subjected to a known combined
radial and thrust load, which must be applied so that to avoid tilting
between inner and outer rings, is used to find the load distribution
differences between a loaded unfitted bearing at room temperature,
and the same loaded bearing with interference fits that might
experience radial temperature gradients between inner and outer
rings. For each step of the procedure it is required the iterative
solution of Z + 2 simultaneous nonlinear equations – where Z is the
number of the balls – to yield exact solution for axial and radial
deflections, and contact angles.
Abstract: Although face recognition seems as an easy task for
human, automatic face recognition is a much more challenging task
due to variations in time, illumination and pose. In this paper, the
influence of time-lapse on visible and thermal images is examined.
Orthogonal moment invariants are used as a feature extractor to
analyze the effect of time-lapse on thermal and visible images and the
results are compared with conventional Principal Component
Analysis (PCA). A new triangle square ratio criterion is employed
instead of Euclidean distance to enhance the performance of nearest
neighbor classifier. The results of this study indicate that the ideal
feature vectors can be represented with high discrimination power
due to the global characteristic of orthogonal moment invariants.
Moreover, the effect of time-lapse has been decreasing and enhancing
the accuracy of face recognition considerably in comparison with
PCA. Furthermore, our experimental results based on moment
invariant and triangle square ratio criterion show that the proposed
approach achieves on average 13.6% higher in recognition rate than
PCA.
Abstract: The wide increase and diffusion on telecommunication
technologies have caused a huge spread of electromagnetic sources
in most European Countries. Since the public is continuously being
exposed to electromagnetic radiation the possible health effects have
become the focus of population concerns. As a result, electromagnetic
field monitoring stations which control field strength in commercial
frequency bands are being placed on the flat roof of many buildings.
However there is no guidance on where to place them. This paper
presents an analysis of frequency, polarization and angles of incidence
of a plane wave which impinges on a flat roof security wall and its
dependence on electromagnetic field strength meters placement.
Abstract: The purpose of this work is measurement of the
system presampling MTF of a variable resolution x-ray (VRX) CT
scanner. In this paper, we used the parameters of an actual VRX CT
scanner for simulation and study of effect of different focal spot sizes
on system presampling MTF by Monte Carlo method (GATE
simulation software). Focal spot size of 0.6 mm limited the spatial
resolution of the system to 5.5 cy/mm at incident angles of below 17º
for cell#1. By focal spot size of 0.3 mm the spatial resolution
increased up to 11 cy/mm and the limiting effect of focal spot size
appeared at incident angles of below 9º. The focal spot size of 0.3
mm could improve the spatial resolution to some extent but because
of magnification non-uniformity, there is a 10 cy/mm difference
between spatial resolution of cell#1 and cell#256. The focal spot size
of 0.1 mm acted as an ideal point source for this system. The spatial
resolution increased to more than 35 cy/mm and at all incident angles
the spatial resolution was a function of incident angle. By the way
focal spot size of 0.1 mm minimized the effect of magnification nonuniformity.
Abstract: The modeling of inelastic behavior of plastic materials requires measurements providing information on material response to different multiaxial loading conditions. Different triaxiality conditions and values of Lode parameters have to be
covered for complex description of the material plastic behavior.
Samples geometries providing material plastic behavoiur over the range of interest are proposed with the use of FEM analysis. Round samples with 3 different notches and smooth surface are used
together with butterfly type of samples tested at angle ranging for 0 to
90°. Identification of ductile damage parameters is carried out on
the basis of obtained experimental data for austenitic stainless steel.
The obtained material plastic damage parameters are subsequently applied to FEM simulation of notched CT normally samples used for
fracture mechanics testing and results from the simulation are
compared with real tests.
Abstract: In this study, some physical and mechanical properties
of jujube fruits, were measured and compared at constant moisture
content of 15.5% w.b. The results showed that the mean length, width
and thickness of jujube fruits were 18.88, 16.79 and 15.9 mm,
respectively. The mean projected areas of jujube perpendicular to
length, width, and thickness were 147.01, 224.08 and 274.60 mm2,
respectively. The mean mass and volume were 1.51 g and 2672.80
mm3, respectively. The arithmetic mean diameter, geometric mean
diameter and equivalent diameter varied from 14.53 to 20 mm, 14.5
to 19.94 mm, and 14.52 to 19.97 mm, respectively. The sphericity,
aspect ratio and surface area of jujube fruits were 0.91, 0.89 and
926.28 mm2, respectively. Whole fruit density, bulk density and
porosity of jujube fruits were measured and found to be 1.52 g/cm3,
0.3 g/cm3 and 79.3%, respectively. The angle of repose of jujube fruit
was 14.66° (±0.58°). The static coefficient of friction on galvanized
iron steel was higher than that on plywood and lower than that on
glass surface. The values of rupture force, deformation, hardness and
energy absorbed were found to be between 11.13-19.91N, 2.53-
4.82mm, 3.06-5.81N mm and 20.13-39.08 N/mm, respectively.
Abstract: The paper provides a numerical investigation of the
entropy generation analysis due to natural convection in an inclined
square porous cavity. The coupled equations of mass, momentum,
energy and species conservation are solved using the Control Volume
Finite-Element Method. Effect of medium permeability and
inclination angle on entropy generation is analysed. It was found that
according to the Darcy number and the porous thermal Raleigh
number values, the entropy generation could be mainly due to heat
transfer or to fluid friction irreversibility and that entropy generation
reaches extremum values for specific inclination angles.
Abstract: This paper deals with the analysis of active constrained layer damping (ACLD) of doubly curved laminated composite shells using active fiber composite (AFC) materials. The constraining layer of the ACLD treatment has been considered to be made of the AFC materials. A three dimensional energy based finite element model of the smart doubly curved laminated composite shell integrated with a patch of such ACLD treatment has been developed to demonstrate the performance of the patch on enhancing the damping characteristics of the doubly curved laminated composite shells. Particular emphasis has been placed on studying the effect of variation of piezoelectric fiber orientation angle in the constraining AFC layer on the control authority of the ACLD patch.
Abstract: This paper deals with the experimental investigations
of the in-cylinder tumble flows in an unfired internal combustion
engine with a flat piston at the engine speeds ranging from 400 to
1000 rev/min., and also with the dome and dome-cavity pistons at an
engine speed of 1000 rev/min., using particle image velocimetry.
From the two-dimensional in-cylinder flow measurements, tumble
flow analysis is carried out in the combustion space on a vertical
plane passing through cylinder axis. To analyze the tumble flows,
ensemble average velocity vectors are used and to characterize it,
tumble ratio is estimated. From the results, generally, we have found
that tumble ratio varies mainly with crank angle position. Also, at the
end of compression stroke, average turbulent kinetic energy is more
at higher engine speeds. We have also found that, at 330 crank angle
position, flat piston shows an improvement of about 85 and 23% in
tumble ratio, and about 24 and 2.5% in average turbulent kinetic
energy compared to dome and dome-cavity pistons respectively
Abstract: For micro-gyroscopes, the angular rate detection components have to oscillate forwards and backwards alternatively. An innovative design of micro-electromagnetic drive module is proposed to make a Π-type disc reciprocally and efficiently rotate within a certain of angular interval. Twelve Electromagnetic poles enclosing the thin disc are designed to provide the magnetic drive power. Isotropic etching technique is employed to fabricate the high-aspect-ratio trench, so that the contact angle of wire against trench can be increased and the potential defect of cavities and pores within the wire can be prevented. On the other hand, a Π-type thin disc is designed to conduct the pitch motion as an angular excitation, in addition to spinning, is exerted on the gyroscope. The efficacy of the micro-magnetic drive module is verified by the commercial software, Ansoft Maxewll. In comparison with the conventional planar windings in micro-scale systems, the magnetic drive force is increased by 150%.
Abstract: Traditionally, wind tunnel models are made of metal
and are very expensive. In these years, everyone is looking for ways
to do more with less. Under the right test conditions, a rapid
prototype part could be tested in a wind tunnel. Using rapid prototype
manufacturing techniques and materials in this way significantly
reduces time and cost of production of wind tunnel models. This
study was done of fused deposition modeling (FDM) and their ability
to make components for wind tunnel models in a timely and cost
effective manner. This paper discusses the application of wind tunnel
model configuration constructed using FDM for transonic wind
tunnel testing. A study was undertaken comparing a rapid
prototyping model constructed of FDM Technologies using
polycarbonate to that of a standard machined steel model. Testing
covered the Mach range of Mach 0.3 to Mach 0.75 at an angle-ofattack
range of - 2° to +12°. Results from this study show relatively
good agreement between the two models and rapid prototyping
Method reduces time and cost of production of wind tunnel models.
It can be concluded from this study that wind tunnel models
constructed using rapid prototyping method and materials can be
used in wind tunnel testing for initial baseline aerodynamic database
development.
Abstract: A known iterative computational procedure is used for
internal normal ball loads calculation in statically loaded single-row,
angular-contact ball bearings, subjected to a known thrust load,
which is applied in the inner ring at the geometric bearing center line.
Numerical aspects of the iterative procedure are discussed.
Numerical examples results for a 218 angular-contact ball bearing
have been compared with those from the literature. Twenty figures
are presented showing the geometrical features, the behavior of the
convergence variables and the following parameters as functions of
the thrust load: normal ball loads, contact angle, distance between
curvature centers, and normal ball and axial deflections between the
raceways.
Abstract: In this paper, Neuro-Fuzzy based Fuzzy Subtractive
Clustering Method (FSCM) and Self Tuning Fuzzy PD-like
Controller (STFPDC) were used to solve non-linearity and trajectory
problems of pitch AND yaw angles of Twin Rotor MIMO system
(TRMS). The control objective is to make the beams of TRMS reach
a desired position quickly and accurately. The proposed method
could achieve control objectives with simpler controller. To simplify
the complexity of STFPDC, ANFIS based FSCM was used to
simplify the controller and improve the response. The proposed
controllers could achieve satisfactory objectives under different input
signals. Simulation results under MATLAB/Simulink® proved the
improvement of response and superiority of simplified STFPDC on
Fuzzy Logic Controller (FLC).
Abstract: In this paper a controller for the pitch angle of an
aircraft regarding to the elevator deflection angle is designed.
The way how the elevator angle affects pitching motion of the
aircraft is pointed out, as well as, how a pitch controller can be
applied for the aircraft to reach certain pitch angle. In this digital
optimal system, the elevator deflection angle and pitching angle
of the plane are considered to be input and output respectively.
A single input single output (SISO) system is presented. A
digital pitch aircraft control is demonstrated. A simulation for
the whole system has been performed. The optimal control
weighting vectors, Q and R have been determined.
Abstract: This paper deals with new concept of using compressed atmospheric air as a zero pollution power source for running motorbikes. The motorbike is equipped with an air turbine in place of an internal combustion engine, and transforms the energy of the compressed air into shaft work. The mathematical modeling and performance evaluation of a small capacity compressed air driven vaned type novel air turbine is presented in this paper. The effect of isobaric admission and adiabatic expansion of high pressure air for different rotor to casing diameter ratios with respect to different vane angles (number of vanes) have been considered and analyzed. It is found that the shaft work output is optimum for some typical values of rotor / casing diameter ratios at a particular value of vane angle (no. of vanes). In this study, the maximum power is obtained as 4.5kW - 5.3kW (5.5-6.25 HP) when casing diameter is taken 100 mm, and rotor to casing diameter ratios are kept from 0.65 to 0.55. This value of output is sufficient to run motorbike.
Abstract: Renewed interest in propeller propulsion on aircraft
configurations combined with higher propeller loads lead to the question how the effects of the propulsion on model support disturbances
should be accounted for. In this paper, the determination of engine power effects on support interference of sting-mounted models is
demonstrated by a measurement on a four-engine turboprop aircraft.
CFD results on a more generic model are presented in order to clarify
the possible mechanism behind engine power effects on support
interference. The engine slipstream induces a local change in angle
of sideslip at the model sting thereby influencing the sting near-field and far-field effects. Whether or not the net result of these changes
in the disturbance pattern leads to a significant engine power effect depends on the configuration of the wind tunnel model and the test
setup.
Abstract: This paper presented two new efficient algorithms
for contour approximation. The proposed algorithm is compared
with Ramer (good quality), Triangle (faster) and Trapezoid (fastest)
in this work; which are briefly described. Cartesian co-ordinates of
an input contour are processed in such a manner that finally
contours is presented by a set of selected vertices of the edge of the
contour. In the paper the main idea of the analyzed procedures for
contour compression is performed. For comparison, the mean
square error and signal-to-noise ratio criterions are used.
Computational time of analyzed methods is estimated depending on
a number of numerical operations. Experimental results are
obtained both in terms of image quality, compression ratios, and
speed. The main advantages of the analyzed algorithm is small
numbers of the arithmetic operations compared to the existing
algorithms.
Abstract: This paper describes a new measuring algorithm for
three-dimensional (3-D) braided composite material .Braided angle is
an important parameter of braided composites. The objective of this
paper is to present an automatic measuring system. In the paper, the
algorithm is performed by using vcµ6.0 language on PC. An
advanced filtered algorithm for image of 3-D braided composites
material performs has been developed. The procedure is completely
automatic and relies on the gray scale information content of the
images and their local wavelet transform modulus maxims.
Experimental results show that the proposed method is feasible.
The algorithm was tested on both carbon-fiber and glass-fiber
performs.
Abstract: The purpose of this study is to investigate the
efficiency of a double-layer roof in collecting solar energy as an
application to the areas such as raising high-end temperature of
organic Rankine cycle (ORC). The by-product of the solar roof is to
reduce building air-conditioning loads. The experimental apparatus
are arranged to evaluate the effects of the solar roof in absorbing solar
energy. The flow channel is basically formed by an aluminum plate on
top of a plywood plate. The geometric configurations in which the
effects of absorbing energy is analyzed include: a bare uncovered
aluminum plate, a glass-covered aluminum plate, a
glass-covered/black-painted aluminum plate, a plate with variable
lengths, a flow channel with stuffed material (in an attempt on
enhancement of heat conduction), and a flow channel with variable
slanted angles. The experimental results show that the efficiency of
energy collection varies from 0.6 % to 11 % for the geometric
configurations mentioned above. An additional study is carried out
using CFD simulation to investigate the effects of fins on the
aluminum plate. It shows that due to vastly enhanced heat conduction,
the efficiency can reach ~23 % if 50 fins are installed on the aluminum
plate. The study shows that a double-layer roof can efficiently absorb
solar energy and substantially reduce building air-conditioning
loads. On the high end of an organic Rankine cycle, a solar pond is
used to replace the warm surface water of the sea as OTEC (ocean
thermal energy conversion) is the driving energy for the ORC. The
energy collected from the double-layered solar roof can be pumped
into the pond and raise the pond temperature as the pond surface area is
equivalently increased by nearly one-fourth of the total area of the
double-layer solar roof. The effect of raising solar pond temperature is
especially prominent if the double-layer solar roofs are installed in a
community area.