Abstract: The 6th version of Universal modeling method for
centrifugal compressor stage calculation is described. Identification
of the new mathematical model was made. As a result of
identification the uniform set of empirical coefficients is received.
The efficiency definition error is 0,86 % at a design point. The
efficiency definition error at five flow rate points (except a point of
the maximum flow rate) is 1,22 %. Several variants of the stage with
3D impellers designed by 6th version program and quasi threedimensional
calculation programs were compared by their gas
dynamic performances CFD (NUMECA FINE TURBO).
Performance comparison demonstrated general principles of design
validity and leads to some design recommendations.
Abstract: Speech enhancement is a long standing problem with
numerous applications like teleconferencing, VoIP, hearing aids and
speech recognition. The motivation behind this research work is to
obtain a clean speech signal of higher quality by applying the optimal
noise cancellation technique. Real-time adaptive filtering algorithms
seem to be the best candidate among all categories of the speech
enhancement methods. In this paper, we propose a speech
enhancement method based on Recursive Least Squares (RLS)
adaptive filter of speech signals. Experiments were performed on
noisy data which was prepared by adding AWGN, Babble and Pink
noise to clean speech samples at -5dB, 0dB, 5dB and 10dB SNR
levels. We then compare the noise cancellation performance of
proposed RLS algorithm with existing NLMS algorithm in terms of
Mean Squared Error (MSE), Signal to Noise ratio (SNR) and SNR
Loss. Based on the performance evaluation, the proposed RLS
algorithm was found to be a better optimal noise cancellation
technique for speech signals.
Abstract: Vegetation affects the mean and turbulent flow
structure. It may increase flood risks and sediment transport.
Therefore, it is important to develop analytical approaches for the bed
shear stress on vegetated bed, to predict resistance caused by
vegetation. In the recent years, experimental and numerical models
have both been developed to model the effects of submerged
vegetation on open-channel flow. In this paper, different analytic
models are compared and tested using the criteria of deviation, to
explore their capacity for predicting the mean velocity and select the
suitable one that will be applied in real case of rivers. The
comparison between the measured data in vegetated flume and
simulated mean velocities indicated, a good performance, in the case
of rigid vegetation, whereas, Huthoff model shows the best
agreement with a high coefficient of determination (R2=80%) and the
smallest error in the prediction of the average velocities.
Abstract: Construction cost estimation is one of the most
important aspects of construction project design. For generations, the
process of cost estimating has been manual, time-consuming and
error-prone. This has partly led to most cost estimates to be unclear
and riddled with inaccuracies that at times lead to over- or underestimation
of construction cost. The development of standard set of
measurement rules that are understandable by all those involved in a
construction project, have not totally solved the challenges. Emerging
Building Information Modelling (BIM) technologies can exploit
standard measurement methods to automate cost estimation process
and improve accuracies. This requires standard measurement
methods to be structured in ontological and machine readable format;
so that BIM software packages can easily read them. Most standard
measurement methods are still text-based in textbooks and require
manual editing into tables or Spreadsheet during cost estimation. The
aim of this study is to explore the development of an ontology based
on New Rules of Measurement (NRM) commonly used in the UK for
cost estimation. The methodology adopted is Methontology, one of
the most widely used ontology engineering methodologies. The
challenges in this exploratory study are also reported and
recommendations for future studies proposed.
Abstract: High Peak to Average Power Ratio (PAPR) of the
transmitted signal is a serious problem in multicarrier systems (MC),
such as Orthogonal Frequency Division Multiplexing (OFDM), or in
Multi-Carrier Code Division Multiple Access (MC-CDMA) systems,
due to large number of subcarriers. This effect is possible reduce with
some PAPR reduction techniques. Spreading sequences at the
presence of Saleh and Rapp models of high power amplifier (HPA)
have big influence on the behavior of system. In this paper we
investigate the bit-error-rate (BER) performance of MC-CDMA
systems. Basically we can see from simulations that the MC-CDMA
system with Iterative algorithm can be providing significantly better
results than the MC-CDMA system. The results of our analyses are
verified via simulation.
Abstract: The number of Ground Motion Prediction Equations
(GMPEs) used for predicting peak ground acceleration (PGA) and
the number of earthquake recordings that have been used for fitting
these equations has increased in the past decades. The current PF-L
database contains 3550 recordings. Since the GMPEs frequently
model the peak ground acceleration the goal of the present study was
to refit a selection of 44 of the existing equation models for PGA in
light of the latest data. The algorithm Levenberg-Marquardt was used
for fitting the coefficients of the equations and the results are
evaluated both quantitatively by presenting the root mean squared
error (RMSE) and qualitatively by drawing graphs of the five best
fitted equations. The RMSE was found to be as low as 0.08 for the
best equation models. The newly estimated coefficients vary from the
values published in the original works.
Abstract: An attempt has been made in the present
communication to elucidate the efficacy of robust ANOVA methods
to analyse horticultural field experimental data in the presence of
outliers. Results obtained fortify the use of robust ANOVA methods
as there was substantiate reduction in error mean square, and hence
the probability of committing Type I error, as compared to the regular
approach.
Abstract: Examining existing experimental results for shallow
rigid foundations subjected to vertical centric load (N), accompanied
or not with a bending moment (M), two main non-linear mechanisms
governing the cyclic response of the soil-foundation system can be
distinguished: foundation uplift and soil yielding. A soil-foundation
failure limit, is defined as a domain of resistance in the two
dimensional (2D) load space (N, M) inside of which lie all the
admissible combinations of loads; these latter correspond to a pure
elastic, non-linear elastic or plastic behavior of the soil-foundation
system, while the points lying on the failure limit correspond to a
combination of loads leading to a failure of the soil-foundation
system. In this study, the proposed resistance domain is constructed
analytically based on mechanics. Original elastic limit, uplift
initiation limit and iso-uplift limits are constructed inside this
domain. These limits give a prediction of the mechanisms activated
for each combination of loads applied to the foundation. A
comparison of the proposed failure limit with experimental tests
existing in the literature shows interesting results. Also, the
developed uplift initiation limit and iso-uplift curves are confronted
with others already proposed in the literature and widely used due to
the absence of other alternatives, and remarkable differences are
noted, showing evident errors in the past proposals and relevant
accuracy for those given in the present work.
Abstract: Proof of controlling crack width is a basic condition
for securing suitable performance in serviceability limit state. The
cracking in concrete can occur at any time from the casting of time to
the years after the concrete has been set in place. Most codes struggle
with offering procedure for crack width calculation. There is lack in
availability of design charts for designers to compute crack width
with ease. The focus of the study is to utilize design charts and
parametric equations in calculating crack width with minimum error.
The paper contains a simplified procedure to calculate crack width
for reinforced concrete (RC) sections subjected to bending with axial
tensile force following the guidelines of Euro code [DS EN-1992-1-1
& DS EN-1992-1-2]. Numerical examples demonstrate the
application of the suggested procedure. Comparison with parallel
analytical tools supports the validity of result and show the
percentage deviation of crack width in both the procedures. The
technique is simple, user friendly and ready to evolve for a greater
spectrum of section sizes and materials.
Abstract: In this paper we describe the Levenvberg-Marquardt
(LM) algorithm for identification and equalization of CDMA
signals received by an antenna array in communication channels.
The synthesis explains the digital separation and equalization of
signals after propagation through multipath generating intersymbol
interference (ISI). Exploiting discrete data transmitted and three
diversities induced at the reception, the problem can be composed
by the Block Component Decomposition (BCD) of a tensor of
order 3 which is a new tensor decomposition generalizing the
PARAFAC decomposition. We optimize the BCD decomposition by
Levenvberg-Marquardt method gives encouraging results compared to
classical alternating least squares algorithm (ALS). In the equalization
part, we use the Minimum Mean Square Error (MMSE) to perform
the presented method. The simulation results using the LM algorithm
are important.
Abstract: One of the major difficulties introduced with wind
power penetration is the inherent uncertainty in production originating
from uncertain wind conditions. This uncertainty impacts many
different aspects of power system operation, especially the balancing
power requirements. For this reason, in power system development
planing, it is necessary to evaluate the potential uncertainty in future
wind power generation. For this purpose, simulation models are
required, reproducing the performance of wind power forecasts.
This paper presents a wind power forecast error simulation models
which are based on the stochastic process simulation. Proposed
models capture the most important statistical parameters recognized
in wind power forecast error time series. Furthermore, two distinct
models are presented based on data availability. First model uses
wind speed measurements on potential or existing wind power plant
locations, while the seconds model uses statistical distribution of wind
speeds.
Abstract: Strong anion exchange resins with QN+OH-, have the
potential to be developed and employed as heterogeneous catalyst for
transesterification, as they are chemically stable to leaching of the
functional group. Nine different SIERs (SIER1-9) with QN+OH-were
prepared by suspension polymerization of vinylbenzyl chloridedivinylbenzene
(VBC-DVB) copolymers in the presence of n-heptane
(pore-forming agent). The amine group was successfully grafted into
the polymeric resin beads through functionalization with
trimethylamine. These SIERs are then used as a catalyst for the
transesterification of triacetin with methanol. A set of differential
equations that represents the Langmuir-Hinshelwood-Hougen-
Watson (LHHW) and Eley-Rideal (ER) models for the
transesterification reaction were developed. These kinetic models of
LHHW and ER were fitted to the experimental data. Overall, the
synthesized ion exchange resin-catalyzed reaction were welldescribed
by the Eley-Rideal model compared to LHHW models,
with sum of square error (SSE) of 0.742 and 0.996, respectively.
Abstract: In this work, neural networks methods MLP type were
applied to a database from an array of six sensors for the detection of
three toxic gases. The choice of the number of hidden layers and the
weight values are influential on the convergence of the learning
algorithm. We proposed, in this article, a mathematical formula to
determine the optimal number of hidden layers and good weight
values based on the method of back propagation of errors. The results
of this modeling have improved discrimination of these gases and
optimized the computation time. The model presented here has
proven to be an effective application for the fast identification of
toxic gases.
Abstract: The ad hoc networks are the future of wireless
technology as everyone wants fast and accurate error free information
so keeping this in mind Bit Error Rate (BER) and power is optimized
in this research paper by using the Genetic Algorithm (GA). The
digital modulation techniques used for this paper are Binary Phase
Shift Keying (BPSK), M-ary Phase Shift Keying (M-ary PSK), and
Quadrature Amplitude Modulation (QAM). This work is
implemented on Wireless Ad Hoc Networks (WLAN). Then it is
analyze which modulation technique is performing well to optimize
the BER and power of WLAN.
Abstract: Taking the design tolerance into account, this paper
presents a novel efficient approach to generate iso-scallop tool path for
five-axis strip machining with a barrel cutter. The cutter location is
first determined on the scallop surface instead of the design surface,
and then the cutter is adjusted to locate the optimal tool position based
on the differential rotation of the tool axis and satisfies the design
tolerance simultaneously. The machining strip width and error are
calculated with the aid of the grazing curve of the cutter. Based on the
proposed tool positioning algorithm, the tool paths are generated by
keeping the scallop height formed by adjacent tool paths constant. An
example is conducted to confirm the validity of the proposed method.
Abstract: We present a trigonometric scheme to approximate a
circular arc with its two end points and two end tangents/unit
tangents. A rational cubic trigonometric Bézier curve is constructed
whose end control points are defined by the end points of the circular
arc. Weight functions and the remaining control points of the cubic
trigonometric Bézier curve are estimated by variational approach to
reproduce a circular arc. The radius error is calculated and found less
than the existing techniques.
Abstract: In this paper, Fuzzy C-Means clustering with
Expectation Maximization-Gaussian Mixture Model based hybrid
modeling algorithm is proposed for Continuous Tamil Speech
Recognition. The speech sentences from various speakers are used
for training and testing phase and objective measures are between the
proposed and existing Continuous Speech Recognition algorithms.
From the simulated results, it is observed that the proposed algorithm
improves the recognition accuracy and F-measure up to 3% as
compared to that of the existing algorithms for the speech signal from
various speakers. In addition, it reduces the Word Error Rate, Error
Rate and Error up to 4% as compared to that of the existing
algorithms. In all aspects, the proposed hybrid modeling for Tamil
speech recognition provides the significant improvements for speechto-
text conversion in various applications.
Abstract: The inspection of underneath vehicle system has been
given significant attention by governments after the threat of
terrorism become more prevalent. New technologies such as mobile
robots and computer vision are led to have more secure environment.
This paper proposed that a mobile robot like Aria robot can be used
to search and inspect the bombs under parking a lot vehicle. This
robot is using fuzzy logic and subsumption algorithms to control the
robot that movies underneath the vehicle. An OpenCV library and
laser Hokuyo are added to Aria robot to complete the experiment for
under vehicle inspection. This experiment was conducted at the
indoor environment to demonstrate the efficiency of our methods to
search objects and control the robot movements under vehicle. We
got excellent results not only by controlling the robot movement but
also inspecting object by the robot camera at same time. This success
allowed us to know the requirement to construct a new cost effective
robot with more functionality.
Abstract: The objective of meta-analysis is to combine results
from several independent studies in order to create generalization
and provide evidence base for decision making. But recent studies
show that the magnitude of effect size estimates reported in many
areas of research significantly changed over time and this can
impair the results and conclusions of meta-analysis. A number of
sequential methods have been proposed for monitoring the effect
size estimates in meta-analysis. However they are based on statistical
theory applicable only to fixed effect model (FEM) of meta-analysis.
For random-effects model (REM), the analysis incorporates the
heterogeneity variance, τ 2 and its estimation create complications.
In this paper we study the use of a truncated CUSUM-type test with
asymptotically valid critical values for sequential monitoring in REM.
Simulation results show that the test does not control the Type I error
well, and is not recommended. Further work required to derive an
appropriate test in this important area of applications.
Abstract: This paper presents the application of the Discrete
Component Model for heating and evaporation to multi-component
biodiesel fuel droplets in direct injection internal combustion engines.
This model takes into account the effects of temperature gradient,
recirculation and species diffusion inside droplets. A distinctive
feature of the model used in the analysis is that it is based on the
analytical solutions to the temperature and species diffusion
equations inside the droplets. Nineteen types of biodiesel fuels are
considered. It is shown that a simplistic model, based on the
approximation of biodiesel fuel by a single component or ignoring
the diffusion of components of biodiesel fuel, leads to noticeable
errors in predicted droplet evaporation time and time evolution of
droplet surface temperature and radius.