Abstract: Software reliability prediction gives a great opportunity to measure the software failure rate at any point throughout system test. A software reliability prediction model provides with the technique for improving reliability. Software reliability is very important factor for estimating overall system reliability, which depends on the individual component reliabilities. It differs from hardware reliability in that it reflects the design perfection. Main reason of software reliability problems is high complexity of software. Various approaches can be used to improve the reliability of software. We focus on software reliability model in this article, assuming that there is a time redundancy, the value of which (the number of repeated transmission of basic blocks) can be an optimization parameter. We consider given mathematical model in the assumption that in the system may occur not only irreversible failures, but also a failure that can be taken as self-repairing failures that significantly affect the reliability and accuracy of information transfer. Main task of the given paper is to find a time distribution function (DF) of instructions sequence transmission, which consists of random number of basic blocks. We consider the system software unreliable; the time between adjacent failures has exponential distribution.
Abstract: The world economic crises and budget constraints
have caused authorities, especially those in developing countries, to
rationalize water quality monitoring activities. Rationalization
consists of reducing the number of monitoring sites, the number of
samples, and/or the number of water quality variables measured. The
reduction in water quality variables is usually based on correlation. If
two variables exhibit high correlation, it is an indication that some of
the information produced may be redundant. Consequently, one
variable can be discontinued, and the other continues to be measured.
Later, the ordinary least squares (OLS) regression technique is
employed to reconstitute information about discontinued variable by
using the continuously measured one as an explanatory variable. In
this paper, two record extension techniques are employed to
reconstitute information about discontinued water quality variables,
the OLS and the Line of Organic Correlation (LOC). An empirical
experiment is conducted using water quality records from the Nile
Delta water quality monitoring network in Egypt. The record
extension techniques are compared for their ability to predict
different statistical parameters of the discontinued variables. Results
show that the OLS is better at estimating individual water quality
records. However, results indicate an underestimation of the variance
in the extended records. The LOC technique is superior in preserving
characteristics of the entire distribution and avoids underestimation
of the variance. It is concluded from this study that the OLS can be
used for the substitution of missing values, while LOC is preferable
for inferring statements about the probability distribution.
Abstract: The major problem that wireless communication
systems undergo is multipath fading caused by scattering of the
transmitted signal. However, we can treat multipath propagation as
multiple channels between the transmitter and receiver to improve
the signal-to-scattering-noise ratio. While using Single Input
Multiple Output (SIMO) systems, the diversity receivers extract
multiple signal branches or copies of the same signal received from
different channels and apply gain combining schemes such as Root
Mean Square Gain Combining (RMSGC). RMSGC asymptotically
yields an identical performance to that of the theoretically optimal
Maximum Ratio Combining (MRC) for values of mean Signal-to-
Noise-Ratio (SNR) above a certain threshold value without the need
for SNR estimation. This paper introduces an improvement of
RMSGC using two different issues. We found that post-detection and
de-noising the received signals improve the performance of RMSGC
and lower the threshold SNR.
Abstract: This paper applies fuzzy set theory to evaluate the
service quality of online auction. Service quality is a composition of
various criteria. Among them many intangible attributes are difficult
to measure. This characteristic introduces the obstacles for respondent
in replying to the survey. So as to overcome this problem, we
invite fuzzy set theory into the measurement of performance. By
using AHP in obtaining criteria and TOPSIS in ranking, we found
the most concerned dimension of service quality is Transaction
Safety Mechanism and the least is Charge Item. Regarding to the
most concerned attributes are information security, accuracy and
information.
Abstract: This paper presents reliability evaluation techniques
which are applied in distribution system planning studies and
operation. Reliability of distribution systems is an important issue in
power engineering for both utilities and customers. Reliability is a
key issue in the design and operation of electric power distribution
systems and load. Reliability evaluation of distribution systems has
been the subject of many recent papers and the modeling and
evaluation techniques have improved considerably.
Abstract: Fip-gts, an immunomodulatory protein purified from Ganoderma tsugae, has been reported to possess therapeutic effects in the treatment of cancer and autoimmune disease. For medicinal application, a recombinant Fip-gts was successfully expressed and purified in Sf21 insect cells by our previously work. It is important to evaluate the immunomodulatory activity of the rFip-gts. To assess the immunomodulatory potential of rFip-gts, the T lymphocytes of murine splenocytes were used in the present study. Results revealed that rFip-gts induced cellular aggregation formation. Additionally, the expression of IL-2 and IFN-r were up-regulated after the treatment of rFip-gts, and a corresponding increased production of IL-2 and IFN-r in a dose-dependent manner. The results showed that rFip-gts has an immunomodulatory activity in inducing Th1 lymphocytes from murine splenocytes released IL-2 and IFN-γ, thus suggest that rFip-gts may have therapeutic potential in vivo as an immune modulator.
Abstract: Research on damage of gears and gear pairs using
vibration signals remains very attractive, because vibration signals
from a gear pair are complex in nature and not easy to interpret.
Predicting gear pair defects by analyzing changes in vibration signal
of gears pairs in operation is a very reliable method. Therefore, a
suitable vibration signal processing technique is necessary to extract
defect information generally obscured by the noise from dynamic
factors of other gear pairs.This article presents the value of cepstrum
analysis in vehicle gearbox fault diagnosis. Cepstrum represents the
overall power content of a whole family of harmonics and sidebands
when more than one family of sidebands is present at the same time.
The concept for the measurement and analysis involved in using the
technique are briefly outlined. Cepstrum analysis is used for detection
of an artificial pitting defect in a vehicle gearbox loaded with
different speeds and torques. The test stand is equipped with three
dynamometers; the input dynamometer serves asthe internal
combustion engine, the output dynamometers introduce the load on
the flanges of the output joint shafts. The pitting defect is
manufactured on the tooth side of a gear of the fifth speed on the
secondary shaft. Also, a method for fault diagnosis of gear faults is
presented based on order Cepstrum. The procedure is illustrated with
the experimental vibration data of the vehicle gearbox. The results
show the effectiveness of Cepstrum analysis in detection and
diagnosis of the gear condition.
Abstract: In 3D-wavelet video coding framework temporal
filtering is done along the trajectory of motion using Motion
Compensated Temporal Filtering (MCTF). Hence computationally
efficient motion estimation technique is the need of MCTF. In this
paper a predictive technique is proposed in order to reduce the
computational complexity of the MCTF framework, by exploiting
the high correlation among the frames in a Group Of Picture (GOP).
The proposed technique applies coarse and fine searches of any fast
block based motion estimation, only to the first pair of frames in a
GOP. The generated motion vectors are supplied to the next
consecutive frames, even to subsequent temporal levels and only fine
search is carried out around those predicted motion vectors. Hence
coarse search is skipped for all the motion estimation in a GOP
except for the first pair of frames. The technique has been tested for
different fast block based motion estimation algorithms over different
standard test sequences using MC-EZBC, a state-of-the-art scalable
video coder. The simulation result reveals substantial reduction (i.e.
20.75% to 38.24%) in the number of search points during motion
estimation, without compromising the quality of the reconstructed
video compared to non-predictive techniques. Since the motion
vectors of all the pair of frames in a GOP except the first pair will
have value ±1 around the motion vectors of the previous pair of
frames, the number of bits required for motion vectors is also
reduced by 50%.
Abstract: This paper aims to develop an algorithm of finite
capacity material requirement planning (FCMRP) system for a multistage
assembly flow shop. The developed FCMRP system has two
main stages. The first stage is to allocate operations to the first and
second priority work centers and also determine the sequence of the
operations on each work center. The second stage is to determine the
optimal start time of each operation by using a linear programming
model. Real data from a factory is used to analyze and evaluate the
effectiveness of the proposed FCMRP system and also to guarantee a
practical solution to the user. There are five performance measures,
namely, the total tardiness, the number of tardy orders, the total
earliness, the number of early orders, and the average flow-time. The
proposed FCMRP system offers an adjustable solution which is a
compromised solution among the conflicting performance measures.
The user can adjust the weight of each performance measure to
obtain the desired performance. The result shows that the combination
of FCMRP NP3 and EDD outperforms other combinations
in term of overall performance index. The calculation time for the
proposed FCMRP system is about 10 minutes which is practical for
the planners of the factory.
Abstract: Superplastic deformation and high temperature load
relaxation behavior of coarse-grained iron aluminides with the
composition of Fe-28 at.% Al have been investigated. A series of load
relaxation and tensile tests were conducted at temperatures ranging
from 600 to 850oC. The flow curves obtained from load relaxation
tests were found to have a sigmoidal shape and to exhibit stress vs.
strain rate data in a very wide strain rate range from 10-7/s to 10-2/s.
Tensile tests have been conducted at various initial strain rates ranging
from 3×10-5/s to 1×10-2/s. Maximum elongation of ~500 % was
obtained at the initial strain rate of 3×10-5/s and the maximum strain
rate sensitivity was found to be 0.68 at 850oC in binary Fe-28Al alloy.
Microstructure observation through the optical microscopy (OM) and
the electron back-scattered diffraction (EBSD) technique has been
carried out on the deformed specimens and it has revealed the
evidences for grain boundary migration and grain refinement to occur
during superplastic deformation, suggesting the dynamic
recrystallization mechanism. The addition of Cr by the amount of 5
at.% appeared to deteriorate the superplasticity of the binary iron
aluminide. By applying the internal variable theory of structural
superplasticity, the addition of Cr has been revealed to lower the
contribution of the frictional resistance to dislocation glide during high
temperature deformation of the Fe3Al alloy.
Abstract: The malfunction of thermal protection system (TPS) caused by aerodynamic heating is a latent trouble to aircraft structure safety. Accurately predicting the structure temperature field is quite important for the TPS design of hypersonic vehicle. Since Thornton’s work in 1988, the coupled method of aerodynamic heating and heat transfer has developed rapidly. However, little attention has been paid to the influence of structural deformation on aerodynamic heating and structural temperature field. In the flight, especially the long-endurance flight, the structural deformation, caused by the aerodynamic heating and temperature rise, has a direct impact on the aerodynamic heating and structural temperature field. Thus, the coupled interaction cannot be neglected. In this paper, based on the method of static aero-thermo-elasticity, considering the influence of aero-thermo-elasticity deformation, the aerodynamic heating and heat transfer coupled results of hypersonic vehicle wing model were calculated. The results show that, for the low-curvature region, such as fuselage or center-section wing, structure deformation has little effect on temperature field. However, for the stagnation region with high curvature, the coupled effect is not negligible. Thus, it is quite important for the structure temperature prediction to take into account the effect of elastic deformation. This work has laid a solid foundation for improving the prediction accuracy of the temperature distribution of aircraft structures and the evaluation capacity of structural performance.
Abstract: In recent years, there has been an increasing interest
toward the use of bovine genotyped embryos for commercial embryo
transfer programs. Biopsy of a few cells in morulla stage is essential
for preimplantation genetic diagnosis (PGD). Low amount of DNA
have limited performing the several molecular analyses within PGD
analyses. Whole genome amplification (WGA) promises to eliminate
this problem. We evaluated the possibility and performance of an
improved primer extension preamplification (I-PEP) method with a
range of starting bovine genomic DNA from 1-8 cells into the WGA
reaction. We optimized a short and simple I-PEP (ssI-PEP) procedure
(~3h). This optimized WGA method was assessed by 6 loci specific
polymerase chain reactions (PCRs), included restriction fragments
length polymorphism (RFLP). Optimized WGA procedure possesses
enough sensitivity for molecular genetic analyses through the few
input cells. This is a new era for generating characterized bovine
embryos in preimplantation stage.
Abstract: This paper presents a model for the evaluation of
energy performance and aerodynamic forces acting on a three-bladed
small vertical axis Darrieus wind turbine depending on blade chord
curvature with respect to rotor axis.
The adopted survey methodology is based on an analytical code
coupled to a solid modeling software, capable of generating the
desired blade geometry depending on the blade design geometric
parameters, which is linked to a finite volume CFD code for the
calculation of rotor performance.
After describing and validating the model with experimental data,
the results of numerical simulations are proposed on the bases of two
different blade profile architectures, which are respectively
characterized by a straight chord and by a curved one, having a chord
radius equal to rotor external circumference. A CFD campaign of
analysis is completed for three blade-candidate airfoil sections, that is
the recently-developed DU 06-W-200 cambered blade profile, a
classical symmetrical NACA 0021 and its derived cambered airfoil,
characterized by a curved chord, having a chord radius equal to rotor
external circumference.
The effects of blade chord curvature on angle of attack, blade
tangential and normal forces are first investigated and then the
overall rotor torque and power are analyzed as a function of blade
azimuthal position, achieving a numerical quantification of the
influence of blade camber on overall rotor performance.
Abstract: This paper reports the evolving properties of a 3 mm low carbon steel plate after Laser Beam Forming achieve this objective, the chemical analyse material and the formed components were carried thereafter both were characterized through microhardness profiling microstructural evaluation and tensile testing. showed an increase in the elemental concentration of the component when compared to the as received attributed to the enhancement property of the LBF process Ultimate Tensile Strength (UTS) and the Vickers the formed component shows an increase when compared to the as received material, this was attributed to strain hardening and grain refinement brought about by the LBF process. The microstructure of the as received steel consists of equiaxed ferrit that of the formed component exhibits elongated orming process (LBF). To es of the as received out and compared; profiling, The chemical analyses formed material; this can be process. The microhardness of ferrite and pearlite while grains.
Abstract: Electrical distribution systems are incurring large losses as the loads are wide spread, inadequate reactive power compensation facilities and their improper control. A comprehensive static VAR compensator consisting of capacitor bank in five binary sequential steps in conjunction with a thyristor controlled reactor of smallest step size is employed in the investigative work. The work deals with the performance evaluation through analytical studies and practical implementation on an existing system. A fast acting error adaptive controller is developed suitable both for contactor and thyristor switched capacitors. The switching operations achieved are transient free, practically no need to provide inrush current limiting reactors, TCR size minimum providing small percentages of nontriplen harmonics, facilitates stepless variation of reactive power depending on load requirement so as maintain power factor near unity always. It is elegant, closed loop microcontroller system having the features of self regulation in adaptive mode for automatic adjustment. It is successfully tested on a distribution transformer of three phase 50 Hz, Dy11, 11KV/440V, 125 KVA capacity and the functional feasibility and technical soundness are established. The controller developed is new, adaptable to both LT & HT systems and practically established to be giving reliable performance.
Abstract: White rust, caused by Albugo candida, is the most
destructive foliar diseases of persian cress, Lepidium sativum in Iran.
Application of fungicide is the most common method for the disease
control. However, regarding the problems created by synthetic
pesticides application, environmentally safe methods are needed to
replace chemical pesticides. In this study, the antifungal activity of
plant natural extracts was investigated for their ability to inhibit
zoospore release from sporangia of A. candida. The crude extract of
46 plants was obtained using methanol. The inhibitory effect of the
extracts was examined by mixing the plant extracts with a
zoosporangial suspension of A. candida (1×106 spore/ml) at three
concentrations, 250, 100 and 50 ppm. The experiments were
conducted in a completely randomized design, with three replicates.
The results of the experiment showed that three out of 46 plants
species, including, Rhus coriaria, Anagallis arvensis and Mespilus
germanica were completely inhibit zoospore release from
zoosporangia of Albugo candida at concentration of 50 ppm.
Abstract: Y chromosome microdeletions are the most common
genetic cause of male infertility and screening for these
microdeletions in azoospermic or severely oligospermic men is now
standard practice. Analysis of the Y chromosome in men with
azoospermia or severe oligozoospermia has resulted in the
identification of three regions in the euchromatic part of the long arm
of the human Y chromosome (Yq11) that are frequently deleted in
men with otherwise unexplained spermatogenic failure. PCR analysis
of microdeletions in the AZFa, AZFb and AZFc regions of the
human Y chromosome is an important screening tool. The aim of this
study was to analyse the type of microdeletions in men with fertility
disorders in Slovakia. We evaluated 227 patients with azoospermia
and with normal karyotype. All patient samples were analyzed
cytogenetically. For PCR amplification of sequence-tagged sites
(STS) of the AZFa, AZFb and AZFc regions of the Y chromosome
was used Devyser AZF set. Fluorescently labeled primers for all
markers in one multiplex PCR reaction were used and for automated
visualization and identification of the STS markers we used genetic
analyzer ABi 3500xl (Life Technologies). We reported 13 cases of
deletions in the AZF region 5,73%. Particular types of deletions were
recorded in each region AZFa,b,c .The presence of microdeletions in
the AZFc region was the most frequent. The study confirmed that
percentage of microdeletions in the AZF region is low in Slovak
azoospermic patients, but important from a prognostic view.
Abstract: This paper describes a method to measure and
compensate a 4 axes ultra-precision machine tool that generates micro
patterns on the large surfaces. The grooving machine is usually used
for making a micro mold for many electrical parts such as a light guide
plate for LCD and fuel cells. The ultra precision machine tool has three
linear axes and one rotational table. Shaping is usually used to
generate micro patterns. In the case of 50 μm pitch and 25 μm height
pyramid pattern machining with a 90° wedge angle bite, one of linear
axis is used for long stroke motion for high cutting speed and other
linear axis are used for feeding. The triangular patterns can be
generated with many times of long stroke of one axis. Then 90°
rotation of work piece is needed to make pyramid patterns with
superposition of machined two triangular patterns.
To make a two dimensional positioning error, straightness of two
axes in out of plane, squareness between the each axis are important.
Positioning errors, straightness and squarness were measured by laser
interferometer system. Those were compensated and confirmed by
ISO230-6. One of difficult problem to measure the error motions is
squareness or parallelism of axis between the rotational table and
linear axis. It was investigated by simultaneous moving of rotary table
and XY axes. This compensation method is introduced in this paper.
Abstract: The electrical and structural properties of Hf/Al/Ni/Au
(20/100/25/50 nm) ohmic contact to n-GaN are reported in this study.
Specific contact resistivities of Hf/Al/Ni/Au based contacts have been
investigated as a function of annealing temperature and achieve the
lowest value of 1.09´10-6 Ω·cm2 after annealing at 650 oC in vacuum.
A detailed mechanism of ohmic contact formation is discussed. By
using different chemical analyses, it is anticipated that the formation of
Hf-Al-N alloy might be responsible to form low temperature ohmic
contacts for the Hf-based scheme to n-GaN.
Abstract: In this paper fatigue crack growth behavior of
aeronautical aluminum alloy 2024 T351 was studied. Effects of
various loading and geometrical parameters are studied such as stress
ratio, amplitude loading, etc. The fatigue crack growth with constant
amplitude is studied using the AFGROW code when NASGRO
model is used. The effect of the stress ratio is highlighted, where one
notices a shift of the curves of crack growth. The comparative study
between two orientations L-T and T-L on fatigue behavior are
presented and shows the variation on the fatigue life. L-T orientation
presents a good fatigue crack growth resistance. Effects of crack
closure are shown in Paris domain and that no crack closure
phenomenons are present at high stress intensity factor.