Abstract: Based on the one-bit-matching principle and by turning the de-mixing matrix into an orthogonal matrix via certain normalization, Ma et al proposed a one-bit-matching learning algorithm on the Stiefel manifold for independent component analysis [8]. But this algorithm is not adaptive. In this paper, an algorithm which can extract kurtosis and its sign of each independent source component directly from observation data is firstly introduced.With the algorithm , the one-bit-matching learning algorithm is revised, so that it can make the blind separation on the Stiefel manifold implemented completely in the adaptive mode in the framework of natural gradient.
Abstract: In this paper, we investigate multihop polling and data gathering schemes in layered sensor networks in order to extend the life time of the networks. A network consists of three layers. The lowest layer contains sensors. The middle layer contains so called super nodes with higher computational power, energy supply and longer transmission range than sensor nodes. The top layer contains a sink node. A node in each layer controls a number of nodes in lower layer by polling mechanism to gather data. We will present four types of data gathering schemes: intermediate nodes do not queue data packet, queue single packet, queue multiple packets and aggregate data, to see which data gathering scheme is more energy efficient for multihop polling in layered sensor networks.
Abstract: The purpose of this study was to determine the most satisfying and frustrating aspects of ICT (Information and Communications Technologies) teaching in Turkish schools. Another aim was to compare these aspects based-on ICT teachers- selfefficacy. Participants were 119 ICT teachers from different geographical areas of Turkey. Participants were asked to list salient satisfying and frustrating aspects of ICT teaching, and to fill out the Self-Efficacy Scale for ICT Teachers. Results showed that the high self-efficacy teachers listed more positive and negative aspects of ICT teaching then did the low self-efficacy teachers. The satisfying aspects of ICT teaching were the dynamic nature of ICT subject, higher student interest, having opportunity to help other subject teachers, and lecturing in well-equipped labs, whereas the most frequently cited frustrating aspects of ICT teaching were ICT-related extra works of schools and colleagues, shortages of hardware and technical problems, indifferent students, insufficient teaching time, and the status of ICT subject in school curriculum. This information could be useful in redesigning ICT teachers- roles and responsibilities as well as job environment in schools.
Abstract: It has been shown that a load discontinuity at the end of
an impulse will result in an extra impulse and hence an extra amplitude
distortion if a step-by-step integration method is employed to yield the
shock response. In order to overcome this difficulty, three remedies
are proposed to reduce the extra amplitude distortion. The first remedy
is to solve the momentum equation of motion instead of the force
equation of motion in the step-by-step solution of the shock response,
where an external momentum is used in the solution of the momentum
equation of motion. Since the external momentum is a resultant of the
time integration of external force, the problem of load discontinuity
will automatically disappear. The second remedy is to perform a single
small time step immediately upon termination of the applied impulse
while the other time steps can still be conducted by using the time step
determined from general considerations. This is because that the extra
impulse caused by a load discontinuity at the end of an impulse is
almost linearly proportional to the step size. Finally, the third remedy
is to use the average value of the two different values at the integration
point of the load discontinuity to replace the use of one of them for
loading input. The basic motivation of this remedy originates from the
concept of no loading input error associated with the integration point
of load discontinuity. The feasibility of the three remedies are
analytically explained and numerically illustrated.
Abstract: The aim of this study is to determine the basic information and communication technology (ICT) skills that may be needed by students studying in the 8th grade of the primary education in their cooperative project works implemented via the Internet. Within the scope of the study, the curriculum used for European Computer Driving License (ECDL) and the curriculum used in Turkey are also compared in terms of the ability to use ICT, which is aimed to be provided to the students. The research population of the study, during which the pre test – post test control group experimental model was used, consisted of 40 students from three different schools. In the first stage of the study, the skills that might be needed by students for their cooperative project works implemented via the Internet were determined through examination of the completed Comenious, e – twinning and WorldLinks projects. In the second stage of the study, the curriculums of the Turkish Ministry of National Education (MEB) and ECDL were evaluated by seven different teachers in line with these skills. Also in this study the ECDL and MEB curriculums were compared in terms of capability to provide the skills to implement cooperative projects via the Internet. In line with the findings of the study, the skills that might be needed by students to implement cooperative projects via the Internet were outlined, and existence of a significant difference was established in favor of the ECDL curriculum upon comparison of both curriculums in accordance with this outline (U = 50,500; p
Abstract: CO2 miscible displacement is not feasible in many oil fields due to high reservoir temperature as higher pressure is required to achieve miscibility. The miscibility pressure is far higher than the formation fracture pressure making it impossible to have CO2 miscible displacement. However, by using oleophilic chemicals, minimum miscibility pressure (MMP) could be lowered. The main objective of this research is to find the best oleophilic chemical in MMP reduction using slim-tube test and Vanishing Interfacial Tension (VIT) The chemicals are selected based on the characteristics that it must be oil soluble, low water solubility, have 4 – 8 carbons, semi polar, economical, and safe for human operation. The families of chemicals chosen are carboxylic acid, alcohol, and ketone. The whole experiment would be conducted at 100°C and the best chemical is said to be effective when it is able to lower CO2-crude oil MMP the most. Findings of this research would have great impact to the oil and gas industry in reduction of operation cost for CO2EOR which is applicable to both onshore and offshore operation.
Abstract: Recently, genetic algorithms (GA) and particle swarm optimization (PSO) technique have attracted considerable attention among various modern heuristic optimization techniques. Since the two approaches are supposed to find a solution to a given objective function but employ different strategies and computational effort, it is appropriate to compare their performance. This paper presents the application and performance comparison of PSO and GA optimization techniques, for Thyristor Controlled Series Compensator (TCSC)-based controller design. The design objective is to enhance the power system stability. The design problem of the FACTS-based controller is formulated as an optimization problem and both the PSO and GA optimization techniques are employed to search for optimal controller parameters. The performance of both optimization techniques in terms of computational time and convergence rate is compared. Further, the optimized controllers are tested on a weakly connected power system subjected to different disturbances, and their performance is compared with the conventional power system stabilizer (CPSS). The eigenvalue analysis and non-linear simulation results are presented and compared to show the effectiveness of both the techniques in designing a TCSC-based controller, to enhance power system stability.
Abstract: Wind is among the potential energy resources which
can be harnessed to generate wind energy for conversion into
electrical power. Due to the variability of wind speed with time and
height, it becomes difficult to predict the generated wind energy more
optimally. In this paper, an attempt is made to establish a
probabilistic model fitting the wind speed data recorded at
Makambako site in Tanzania. Wind speeds and direction were
respectively measured using anemometer (type AN1) and wind Vane
(type WD1) both supplied by Delta-T-Devices at a measurement
height of 2 m. Wind speeds were then extrapolated for the height of
10 m using power law equation with an exponent of 0.47. Data were
analysed using MINITAB statistical software to show the variability
of wind speeds with time and height, and to determine the underlying
probability model of the extrapolated wind speed data. The results
show that wind speeds at Makambako site vary cyclically over time;
and they conform to the Weibull probability distribution. From these
results, Weibull probability density function can be used to predict
the wind energy.
Abstract: In this paper, a new face recognition method based on
PCA (principal Component Analysis), LDA (Linear Discriminant
Analysis) and neural networks is proposed. This method consists of
four steps: i) Preprocessing, ii) Dimension reduction using PCA, iii)
feature extraction using LDA and iv) classification using neural
network. Combination of PCA and LDA is used for improving the
capability of LDA when a few samples of images are available and
neural classifier is used to reduce number misclassification caused by
not-linearly separable classes. The proposed method was tested on
Yale face database. Experimental results on this database
demonstrated the effectiveness of the proposed method for face
recognition with less misclassification in comparison with previous
methods.
Abstract: In the Fe-3%Si sheets, grade Hi-B, with AlN and MnS
as inhibitors, the Goss grains which abnormally grow do not have a
size greater than the average size of the primary matrix. In this
heterogeneous microstructure, the size factor is not a required
condition for the secondary recrystallization. The onset of the small
Goss grain abnormal growth appears to be related to a particular
behavior of their grain boundaries, to the local texture and to the
distribution of the inhibitors. The presence and the evolution of
oriented clusters ensure to the small Goss grains a favorable
neighborhood to grow. The modified Monte-Carlo approach, which
is applied, considers the local environment of each grain. The grain
growth is dependent of its real spatial position; the matrix
heterogeneity is then taken into account. The grain growth conditions
are considered in the global matrix and in different matrixes
corresponding to A component clusters. The grain growth behaviour
is considered with introduction of energy only, energy and mobility,
energy and mobility and precipitates.
Abstract: Among various testing methodologies, Built-in Self-
Test (BIST) is recognized as a low cost, effective paradigm. Also,
full adders are one of the basic building blocks of most arithmetic
circuits in all processing units. In this paper, an optimized testable 2-
bit full adder as a test building block is proposed. Then, a BIST
procedure is introduced to scale up the building block and to generate
a self testable n-bit full adders. The target design can achieve 100%
fault coverage using insignificant amount of hardware redundancy.
Moreover, Overall test time is reduced by utilizing polymorphic
gates and also by testing full adder building blocks in parallel.
Abstract: Linear two-point boundary value problems of order
two are solved using cubic trigonometric B-spline interpolation
method (CTBIM). Cubic trigonometric B-spline is a piecewise
function consisting of trigonometric equations. This method is tested
on some problems and the results are compared with cubic B-spline
interpolation method (CBIM) from the literature. CTBIM is found to
approximate the solution slightly more accurately than CBIM if the
problems are trigonometric.
Abstract: In this paper, a bond graph dynamic model for a valvecontrolled
hydraulic cylinder has been developed. A simplified bond
graph model of the inter-actuator interactions in a multi-cylinder
hydraulic system has also been presented. The overall bond graph
model of a valve-controlled hydraulic cylinder was developed by
combining the bond graph sub-models of the pump, spool valve and
the actuator using junction structures. Causality was then assigned
in order to obtain a computational model which could be simulated.
The causal bond graph model of the hydraulic cylinder was verified
by comparing the open loop state responses to those of an ODE
model which had been developed in literature based on the same
assumptions. The results were found to correlate very well both
in the shape of the curves, magnitude and the response times,
thus indicating that the developed model represents the hydraulic
dynamics of a valve-controlled cylinder. A simplified model for interactuator
interaction was presented by connecting an effort source with
constant pump pressure to the zero-junction from which the cylinders
in a multi-cylinder system are supplied with a constant pressure from
the pump. On simulating the state responses of the developed model
under different situations of cylinder operations, indicated that such
a simple model can be used to predict the inter-actuator interactions.
Abstract: This study explored the relationship between
psychological traits, demographics and financial behavioral biases for
individual investors in Taiwan stock market. By using questionnaire
survey method conducted in 2010, there are 554 valid convenient
samples collected to examine the determinants of three types of
behavioral biases. Based on literature review, two hypothesized
models are constructed and further used to evaluate the effects of big
five personality traits and demographic variables on investment biases
through Structural Equation Model (SEM) analysis. The results
showed that investment biases of individual investors are significantly
related to four personality traits as well as some demographics.
Abstract: The absolute Cu atoms density in Cu(2S1/22P1/2)
ground state has been measured by Resonance Optical Absorption
(ROA) technique in a DC magnetron sputtering deposition with
argon. We measured these densities under variety of operation
conditions: pressure from 0.6 μbar to 14 μbar, input power from
10W to 200W and N2 mixture from 0% to 100%. For measuring the
gas temperature, we used the simulation of N2 rotational spectra
with a special computer code. The absolute number density of Cu
atoms decreases with increasing the N2 percentage of buffer gas at
any conditions of this work. But the deposition rate, is not decreased
with the same manner. The deposition rate variation is very small
and in the limit of quartz balance measuring equipment accuracy. So
we conclude that decrease in the absolute number density of Cu
atoms in magnetron plasma has not a big effect on deposition rate,
because the diffusion of Cu atoms to the chamber volume and
deviation of Cu atoms from direct path (towards the substrate)
decreases with increasing of N2 percentage of buffer gas. This is
because of the lower mass of N2 atoms compared to the argon ones.
Abstract: Many commercial processes are available for the
removal of H2S from gaseous streams. The desulfurization of gas
streams using aqueous ferric sulfate solution as washing liquor is
studied. Apart from sulfur, only H2O is generated in the process, and
consequently, no waste treatment facilities are required. A distinct
advantage of the process is that the reaction of H2S with is so rapid
and complete that there remains no danger of discharging toxic waste
gas. In this study, the reactive absorption of hydrogen sulfide into
aqueous ferric sulfate solution has been studied and design
calculations for equipments have been done and effective operation
parameters on this process considered. Results show that high
temperature and low pressure are suitable for absorption reaction.
Variation of hydrogen sulfide concentration and Fe3+ concentration
with time in absorption reaction shown that the reaction of ferric
sulfate and hydrogen sulfide is first order with respect to the both
reactant. At low Fe2(SO4)3 concentration the absorption rate of H2S
increase with increasing the Fe2(SO4)3 concentration. At higher
concentration a decrease in the absorption rate was found. At higher
concentration of Fe2(SO4)3, the ionic strength and viscosity of
solution increase remarkably resulting in a decrease of solubility,
diffusivity and hence absorption rate.
Abstract: The antioxidant capability of beverage blends made from cocoa, zobo and ginger with standard antioxidant assay procedures was investigated. The DPPH (2,2-diphenyl-1- picrylhydrazyl) scavenging capacity ranged from 21.2-25.8% in comparison with GSH of 37.1%. The ferric reducing ability was highest in the zobo drink and lowest in ginger. The superoxide scavenging capacity was also highest in the zobo drink followed by the drink with alkalized cocoa. The metal chelating power decreased as the level of zobo in the blends decreases. The chelating power of zobo and ginger were significantly lower than the natural and alkalized cocoa. The 100% zobo drink inhibited linoleic acid till the fifth day while natural and alkalized cocoa as well as the blend with 50% alkalized cocoa inhibited linoleic acid greatly till the sixth day. The finding describes the potential health benefit of the phytochemical antioxidants of cocoa:zobo:ginger beverage blends.
Abstract: The job shop scheduling problem (JSSP) is a
notoriously difficult problem in combinatorial optimization. This
paper presents a hybrid artificial immune system for the JSSP with the
objective of minimizing makespan. The proposed approach combines
the artificial immune system, which has a powerful global exploration
capability, with the local search method, which can exploit the optimal
antibody. The antibody coding scheme is based on the operation based
representation. The decoding procedure limits the search space to the
set of full active schedules. In each generation, a local search heuristic
based on the neighborhood structure proposed by Nowicki and
Smutnicki is applied to improve the solutions. The approach is tested
on 43 benchmark problems taken from the literature and compared
with other approaches. The computation results validate the
effectiveness of the proposed algorithm.
Abstract: α-Pinene is the main component of the most
turpentine oils. The hydration of α-pinene with acid catalysts leads to
a complex mixture of monoterpenes. In order to obtain more valuable
products, the α-pinene in the turpentine can be hydrated in dilute
mineral acid solutions to produce α-terpineol. The design of
separation processes requires information on phase equilibrium and
related thermodynamic properties. This paper reports the results of
study on liquid-liquid equilibrium (LLE) of system containing α-
pinene + water and α-terpineol + water.
Binary LLE for α-pinene + water system, and α-terpineol + water
systems were determined by experiment at 301K and atmospheric
pressure. The two component mixture was stirred for about 30min,
then the mixture was left for about 2h for complete phase separation.
The composition of both phases was analyzed by using a Gas
Chromatograph. The experimental data were correlated by
considering both NRTL and UNIQUAC activity coefficient models.
The LLE data for the system of α-pinene + water and α-terpineol +
water were correlated successfully by the NRTL model. The
experimental data were not satisfactorily fitted by the UNIQUAC
model. The NRTL model (α =0.3) correlates the LLE data for the
system of α-pinene + water at 301K with RMSD of 0.0404%. And
the NRTL model (α =0.61) at 301K with RMSD of 0.0058 %. The
NRTL model (α =0.3) correlates the LLE data for the system of α-
terpineol + water at 301K with RMSD of 0.1487% and the NRTL
model (α =0.6) at 301K with RMSD of 0.0032%, between the
experimental and calculated mole fractions.
Abstract: This study mainly aims at assessing the level of
microbial pollution of the water used in the chair system in dental
clinics. For this purpose 36 samples have been randomly collected
from a number of dental surgeries in the city of Tripoli in Libya.
However, 32 of the samples have tested positive to microbial
pollution including 13 of the samples, which have tested positives to
Pseudomonas aeruginosa. Based on the results of the test a further
investigation of the biofilms incorporated within the dental chair
system has been conducted. The laboratory tests of biofilms with
similar design to those found in dental chairs have proved that
bacterial pollution takes place through saliva of the patients who use
the chairs, and that this saliva is rich with nutrients which provides a
suitable breeding ground for all types of bacteria.