Abstract: In this paper the optimal control strategy for
Permanent Magnet Synchronous Motor (PMSM) based drive system
is presented. The designed full optimal control is available for speed
operating range up to base speed. The optimal voltage space-vector
assures input energy reduction and stator loss minimization,
maintaining the output energy in the same limits with the
conventional PMSM electrical drive. The optimal control with three
components is based on the energetically criteria and it is applicable
in numerical version, being a nonrecursive solution. The simulation
results confirm the increased efficiency of the optimal PMSM drive.
The properties of the optimal voltage space vector are shown.
Abstract: To improve the efficiency of parametric studies or
tests planning the method is proposed, that takes into account all input parameters, but only a few simulation runs are performed to
assess the relative importance of each input parameter. For K input
parameters with N input values the total number of possible combinations of input values equals NK. To limit the number of runs,
only some (totally N) of possible combinations are taken into account. The sampling procedure Updated Latin Hypercube
Sampling is used to choose the optimal combinations. To measure the
relative importance of each input parameter, the Spearman rank
correlation coefficient is proposed. The sensitivity and the influence
of all parameters are analyzed within one procedure and the key
parameters with the largest influence are immediately identified.
Abstract: An approach of design of stable of control systems with ultimately wide ranges of uncertainly disturbed parameters is offered. The method relies on using of nonlinear structurally stable functions from catastrophe theory as controllers. Theoretical part presents an analysis of designed nonlinear second-order control systems. As more important the integrators in series, canonical controllable form and Jordan forms are considered. The analysis resumes that due to added controllers systems become stable and insensitive to any disturbance of parameters. Experimental part presents MATLAB simulation of design of control systems of epidemic spread, aircrafts angular motion and submarine depth. The results of simulation confirm the efficiency of offered method of design. KeywordsCatastrophes, robust control, simulation, uncertain parameters.
Abstract: In this study, the reduction of Cr(VI) by use of scrap
iron, a cheap and locally available industrial waste, was investigated
in continuous system. The greater scrap iron efficiency observed for
the first two sections of the column filling indicate that most of the
reduction process was carried out in the bottom half of the column
filling. This was ascribed to a constant decrease of Cr(VI)
concentration inside the filling, as the water front passes from the
bottom to the top end of the column. While the bottom section of the
column filling was heavily passivated with secondary mineral phases,
the top section was less affected by the passivation process; therefore
the column filling would likely ensure the reduction of Cr(VI) for
time periods longer than 216 hours. The experimental results indicate
that fixed beds columns packed with scrap iron could be successfully
used for the first step of Cr(VI) polluted wastewater treatment.
However, the mass of scrap iron filling should be carefully estimated
since it significantly affects the Cr(VI) reduction efficiency.
Abstract: In this paper we propose a new approach to constructing the Delaunay Triangulation and the optimum algorithm for the case of multidimensional spaces (d ≥ 2). Analysing the modern state, it is possible to draw a conclusion, that the ideas for the existing effective algorithms developed for the case of d ≥ 2 are not simple to generalize on a multidimensional case, without the loss of efficiency. We offer for the solving this problem an effective algorithm that satisfies all the given requirements. But theoretical complexity of the problem it is impossible to improve as the Worst - Case Optimality for algorithms of solving such a problem is proved.
Abstract: This paper explains the development of Multifunctional Barcode Inventory Management System (MBIMS) to manage inventory and stock ordering. Today, most of the retailing market is still manually record their stocks and its effectiveness is quite low. By providing MBIMS, it will bring effectiveness to retailing market in inventory management. MBIMS will not only save time in recording input, output and refilling the inventory stock, but also in calculating remaining stock and provide auto-ordering function. This system is developed through System Development Life Cycle (SDLC) and the flow and structure of the system is fully built based on requirements of a retailing market. Furthermore, this system has been developed from methodical research and study where each part of the system is vigilantly designed. Thus, MBIMS will offer a good solution to the retailing market in achieving effectiveness and efficiency in inventory management.
Abstract: Duplicated region detection is a technical method to
expose copy-paste forgeries on digital images. Copy-paste is one
of the common types of forgeries to clone portion of an image
in order to conceal or duplicate special object. In this type of
forgery detection, extracting robust block feature and also high
time complexity of matching step are two main open problems.
This paper concentrates on computational time and proposes a local
block matching algorithm based on block clustering to enhance time
complexity. Time complexity of the proposed algorithm is formulated
and effects of two parameter, block size and number of cluster, on
efficiency of this algorithm are considered. The experimental results
and mathematical analysis demonstrate this algorithm is more costeffective
than lexicographically algorithms in time complexity issue
when the image is complex.
Abstract: A mathematical model for determining the overall efficiency
of a multistage tractor gearbox including all gear, lubricant,
surface finish related parameters and operating conditions is
presented. Sliding friction, rolling friction and windage losses were
considered as the main sources of power loss in the gearing system. A
computer code in FORTRAN was developed to simulate the model.
Sliding friction contributes about 98% of the total power loss for
gear trains operating at relatively low speeds (less than 2000 rpm
input speed). Rolling frictional losses decrease with increased load
while windage losses are only significant for gears running at very
high speeds (greater than 3000 rpm). The results also showed that the
overall efficiency varies over the path of contact of the gear meshes
ranging between 94% to 99.5%.
Abstract: The investigation results of high-density hydrogen
heating by high-current electric arc are presented at initial pressure
from 5 MPa to 160 MPa with current amplitude up to 1.6 MA and
current rate of rise 109-1011 A/s. When changing the initial pressure
and current rate of rise, channel temperature varies from several
electronvolts to hundreds electronvolts. Arc channel radius is several
millimeters. But the radius of the discharge chamber greater than the
radius of the arc channel on approximately order of magnitude. High
efficiency of gas heating is caused by radiation absorption of
hydrogen surrounding the arc. Current channel consist from vapor of
the initiating wire. At current rate of rise of 109 A/s and relatively
small current amplitude gas heating occurs due to radiation
absorption in the band transparency of hydrogen by the wire vapours
with photon energies less than 13.6 eV. At current rate of rise of
1011 A/s gas heating is due to hydrogen absorption of soft X-rays
from discharge channel.
Abstract: In this paper, linear multistep technique using power
series as the basis function is used to develop the block methods
which are suitable for generating direct solution of the special second
order ordinary differential equations with associated initial or
boundary conditions. The continuous hybrid formulations enable us
to differentiate and evaluate at some grids and off – grid points to
obtain two different four discrete schemes, each of order (5,5,5,5)T,
which were used in block form for parallel or sequential solutions of
the problems. The computational burden and computer time wastage
involved in the usual reduction of second order problem into system
of first order equations are avoided by this approach. Furthermore, a
stability analysis and efficiency of the block methods are tested on
linear and non-linear ordinary differential equations and the results
obtained compared favorably with the exact solution.
Abstract: This paper presents a physics-based model for the
high-voltage fast recovery diodes. The model provides a good
trade-off between reverse recovery time and forward voltage drop
realized through a combination of lifetime control and emitter
efficiency reduction techniques. The minority carrier lifetime can be
extracted from the reverse recovery transient response and forward
characteristics. This paper also shows that decreasing the amount of
the excess carriers stored in the drift region will result in softer
characteristics which can be achieved using a lower doping level. The
developed model is verified by experiment and the measurement data
agrees well with the model.
Abstract: This Paper presents a particle swarm optimization (PSO) method for determining the optimal proportional-integral-derivative (PID) controller parameters, for speed control of a linear brushless DC motor. The proposed approach has superior features, including easy implementation, stable convergence characteristic and good computational efficiency. The brushless DC motor is modelled in Simulink and the PSO algorithm is implemented in MATLAB. Comparing with Genetic Algorithm (GA) and Linear quadratic regulator (LQR) method, the proposed method was more efficient in improving the step response characteristics such as, reducing the steady-states error; rise time, settling time and maximum overshoot in speed control of a linear brushless DC motor.
Abstract: Amphawa is the most popular weekend destination for
both domestic and international tourists in Thailand. More than 112
homestays and resorts have been developed along the water
resources. This research aims to initiate appropriate environmental
management system for riverside tourist accommodations in
Amphawa by investigating current environmental characteristics.
Eighty-eight riverside tourist accommodations were survey from
specific questionnaire, GPS data were also gathered for spatial
analysis. The results revealed that the accommodations are welled
manage in regards to some environmental aspects. In order to reduce
economic costs, energy efficiency equipment is utilized. A substantial
number of tourist accommodations encouraged waste separation,
followed by transfer to local administration organization. Grease
traps also utilized in order to decrease chemical discharged, grease
and oil from canteen and restaurants on natural environment. The
most notable mitigation is to initiate environmental friendly cleansers
for tourist accommodation along the riverside in tourism destinations.
Abstract: A considerable amount of energy is consumed during
transmission and reception of messages in a wireless mesh network
(WMN). Reducing per-node transmission power would greatly
increase the network lifetime via power conservation in addition to
increasing the network capacity via better spatial bandwidth reuse. In
this work, the problem of topology control in a hybrid WMN of
heterogeneous wireless devices with varying maximum transmission
ranges is considered. A localized distributed topology control
algorithm is presented which calculates the optimal transmission
power so that (1) network connectivity is maintained (2) node
transmission power is reduced to cover only the nearest neighbours
(3) networks lifetime is extended. Simulations and analysis of results
are carried out in the NS-2 environment to demonstrate the
correctness and effectiveness of the proposed algorithm.
Abstract: Linear induction motors are used in various industries
but they have some specific phenomena which are the causes for
some problems. The most important phenomenon is called end effect.
End effect decreases efficiency, power factor and output force and
unbalances the phase currents. This phenomenon is more important
in medium and high speeds machines. In this paper a factor, EEF , is
obtained by an accurate equivalent circuit model, to determine the
end effect intensity. In this way, all of effective design parameters on
end effect is described. Accuracy of this equivalent circuit model is
evaluated by two dimensional finite-element analysis using ANSYS.
The results show the accuracy of the equivalent circuit model.
Abstract: IFP Group Technology “Sulfrex process" was used in
Iran-s South Pars Gas Complex Refineries for removing sulfur
compounds such as mercaptans, carbonyl sulfide and hydrogen
sulfide, which uses sulfonated cobalt phthalocyanine dispersed in
alkaline solution as catalyst. In this technology, catalyst and alkaline
solution were used circularly. However the stability of catalyst due to
effect of some parameters would reduce with the running of the unit
and therefore sweetening efficiency would be decreased. Hence, the
aim of this research is study the factors effecting on the stability of
catalyst.
Abstract: Gas turbine systems with wet compression have a
potential for future power generation, since they can offer a high
efficiency and a high specific power with a relatively low cost. In this
study influence of ambient condition on the performance of the wet
compression process is investigated with a non-equilibrium analytical
modeling based on droplet evaporation. Transient behaviors of droplet
diameter and temperature of mixed air are investigated for various
ambient temperatures. Special attention is paid for the effects of
ambient temperature, pressure ratio, and water injection ratios on the
important wet compression variables including compressor outlet
temperature and compression work. Parametric studies show that
downing of the ambient temperature leads to lower compressor outlet
temperature and consequently lower consumption of compression
work even in wet compression processes.
Abstract: Com Poisson distribution is capable of modeling the count responses irrespective of their mean variance relation and the parameters of this distribution when fitted to a simple cross sectional data can be efficiently estimated using maximum likelihood (ML) method. In the regression setup, however, ML estimation of the parameters of the Com Poisson based generalized linear model is computationally intensive. In this paper, we propose to use quasilikelihood (QL) approach to estimate the effect of the covariates on the Com Poisson counts and investigate the performance of this method with respect to the ML method. QL estimates are consistent and almost as efficient as ML estimates. The simulation studies show that the efficiency loss in the estimation of all the parameters using QL approach as compared to ML approach is quite negligible, whereas QL approach is lesser involving than ML approach.
Abstract: This paper is aimed to give an illustration on the
application of Data Envelopment Analysis (DEA) as a tool to assess
Quality Management (QM) efficiency. A variant of DEA, slack based
measure (SBM) is used for this purpose. From this study, it is found
that DEA is suitable to measure QM efficiency and give
improvement suggestions to the inefficient QM.
Abstract: We present here the results for a comparative study of
some techniques, available in the literature, related to the relevance
feedback mechanism in the case of a short-term learning. Only one
method among those considered here is belonging to the data mining
field which is the K-nearest neighbors algorithm (KNN) while the
rest of the methods is related purely to the information retrieval field
and they fall under the purview of the following three major axes:
Shifting query, Feature Weighting and the optimization of the
parameters of similarity metric. As a contribution, and in addition to
the comparative purpose, we propose a new version of the KNN
algorithm referred to as an incremental KNN which is distinct from
the original version in the sense that besides the influence of the
seeds, the rate of the actual target image is influenced also by the
images already rated. The results presented here have been obtained
after experiments conducted on the Wang database for one iteration
and utilizing color moments on the RGB space. This compact
descriptor, Color Moments, is adequate for the efficiency purposes
needed in the case of interactive systems. The results obtained allow
us to claim that the proposed algorithm proves good results; it even
outperforms a wide range of techniques available in the literature.