Abstract: Calcium oxide (CaO) as carbon dioxide (CO2)
adsorbent at the elevated temperature has been very well-received
thus far. The CaO can be synthesized from natural calcium carbonate
(CaCO3) sources through the reversible calcination-carbonation
process. In the study, cockle shell has been selected as CaO
precursors. The objectives of the study are to investigate the
performance of calcination and carbonation with respect to different
temperature, heating rate, particle size and the duration time. Overall,
better performance is shown at the calcination temperature of 850oC
for 40 minutes, heating rate of 20oC/min, particle size of < 0.125mm
and the carbonation temperature is at 650oC. The synthesized
materials have been characterized by nitrogen physisorption and
surface morphology analysis. The effectiveness of the synthesized
cockle shell in capturing CO2 (0.72 kg CO2/kg adsorbent) which is
comparable to the commercialized adsorbent (0.60 kg CO2/kg
adsorbent) makes them as the most promising materials for CO2
capture.
Abstract: An adaptive dynamic cerebellar model articulation
controller (DCMAC) neural network used for solving the prediction
and identification problem is proposed in this paper. The proposed
DCMAC has superior capability to the conventional cerebellar model
articulation controller (CMAC) neural network in efficient learning
mechanism, guaranteed system stability and dynamic response. The
recurrent network is embedded in the DCMAC by adding feedback
connections in the association memory space so that the DCMAC
captures the dynamic response, where the feedback units act as
memory elements. The dynamic gradient descent method is adopted to
adjust DCMAC parameters on-line. Moreover, the analytical method
based on a Lyapunov function is proposed to determine the
learning-rates of DCMAC so that the variable optimal learning-rates
are derived to achieve most rapid convergence of identifying error.
Finally, the adaptive DCMAC is applied in two computer simulations.
Simulation results show that accurate identifying response and
superior dynamic performance can be obtained because of the
powerful on-line learning capability of the proposed DCMAC.
Abstract: This paper presents an algorithm for reconstructing phase and magnitude responses of the impulse response when only the output data are available. The system is driven by a zero-mean independent identically distributed (i.i.d) non-Gaussian sequence that is not observed. The additive noise is assumed to be Gaussian. This is an important and essential problem in many practical applications of various science and engineering areas such as biomedical, seismic, and speech processing signals. The method is based on evaluating the bicepstrum of the third-order statistics of the observed output data. Simulations results are presented that demonstrate the performance of this method.
Abstract: The aim of this research was to calculate the
mechanical properties of Pd3Rh and PdRh3 ordered alloys. The
molecular dynamics (MD) simulation technique was used to obtain
temperature dependence of the energy, the Yong modulus, the shear
modulus, the bulk modulus, Poisson-s ratio and the elastic stiffness
constants at the isobaric-isothermal (NPT) ensemble in the range of
100-325 K. The interatomic potential energy and force on atoms were
calculated by Quantum Sutton-Chen (Q-SC) many body potential.
Our MD simulation results show the effect of temperature on the
cohesive energy and mechanical properties of Pd3Rh as well as
PdRh3 alloys. Our computed results show good agreement with the
experimental results where they have been available.
Abstract: The purpose of suspension system in automobiles is to
improve the ride comfort and road handling. In this research the ride
and handling performance of a specific automobile with passive
suspension system is compared to a proposed fuzzy logic semi active
suspension system designed for that automobile. The bodysuspension-
wheel system is modeled as a two degree of freedom
quarter car model. MATLAB/SIMULINK [1] was used for
simulation and controller design. The fuzzy logic controller is based
on two inputs namely suspension velocity and body velocity. The
output of the fuzzy controller is the damping coefficient of the
variable damper. The result shows improvement over passive
suspension method.
Abstract: Fault tolerance is critical in many of today's large computer systems. This paper focuses on improving fault tolerance through testing. Moreover, it concentrates on the memory faults: how to access the editable part of a process memory space and how this part is affected. A special Software Fault Injection Technique (SFIT) is proposed for this purpose. This is done by sequentially scanning the memory of the target process, and trying to edit maximum number of bytes inside that memory. The technique was implemented and tested on a group of programs in software packages such as jet-audio, Notepad, Microsoft Word, Microsoft Excel, and Microsoft Outlook. The results from the test sample process indicate that the size of the scanned area depends on several factors. These factors are: process size, process type, and virtual memory size of the machine under test. The results show that increasing the process size will increase the scanned memory space. They also show that input-output processes have more scanned area size than other processes. Increasing the virtual memory size will also affect the size of the scanned area but to a certain limit.
Abstract: In this paper, we present a non-blind technique of
adding the watermark to the Fourier spectral components of audio
signal in a way such that the modified amplitude does not exceed the
maximum amplitude spread (MAS). This MAS is due to individual
Discrete fourier transform (DFT) coefficients in that particular frame,
which is derived from the Energy Spreading function given by
Schroeder. Using this technique one can store double the information
within a given frame length i.e. overriding the watermark on the
host of equal length with least perceptual distortion. The watermark
is uniformly floating on the DFT components of original signal.
This helps in detecting any intentional manipulations done on the
watermarked audio. Also, the scheme is found robust to various signal
processing attacks like presence of multiple watermarks, Additive
white gaussian noise (AWGN) and mp3 compression.
Abstract: Synchronous cooperative systems (SCS) bring together users that are geographically distributed and connected through a network to carry out a task. Examples of SCS include Tele- Immersion and Tele-Conferences. In SCS, the coordination is the core of the system, and it has been defined as the act of managing interdependencies between activities performed to achieve a goal. Some of the main problems that SCS present deal with the management of constraints between simultaneous activities and the execution ordering of these activities. In order to resolve these problems, orderings based on Lamport-s happened-before relation have been used, namely, causal, Δ-causal, and causal-total orderings. They mainly differ in the degree of asynchronous execution allowed. One of the most important orderings is the causal order, which establishes that the events must be seen in the cause-effect order as they occur in the system. In this paper we show that for certain SCS (e.g. videoconferences, tele-immersion) where some degradation of the system is allowed, ensuring the causal order is still rigid, which can render negative affects to the system. In this paper, we illustrate how a more relaxed ordering, which we call Fuzzy Causal Order (FCO), is useful for such kind of systems by allowing a more asynchronous execution than the causal order. The benefit of the FCO is illustrated by applying it to a particular scenario of intermedia synchronization of an audio-conference system.
Abstract: We investigate sonic cues for binaural sound localization within classrooms and present a structural model for the same. Two of the primary cues for localization, interaural time difference (ITD) and interaural level difference (ILD) created between the two ears by sounds from a particular point in space, are used. Although these cues do not lend any information about the elevation of a sound source, the torso, head, and outer ear carry out elevation dependent spectral filtering of sounds before they reach the inner ear. This effect is commonly captured in head related transfer function (HRTF) which aids in resolving the ambiguity from the ITDs and ILDs alone and helps localize sounds in free space. The proposed structural model of HRTF produces well controlled horizontal as well as vertical effects. The implemented HRTF is a signal processing model which tries to mimic the physical effects of the sounds interacting with different parts of the body. The effectiveness of the method is tested by synthesizing spatial audio, in MATLAB, for use in listening tests with human subjects and is found to yield satisfactory results in comparison with existing models.
Abstract: This paper presents results of an experimental study performed to investigate effect of incorporating silica fume on physico-mechanical properties and durability of resulting fly ash geopolymers. Geopolymer specimens were prepared by activating fly ash incorporated with additional silica fume in the range of 2.5% to 5%, with a mixture of sodium hydroxide and sodium silicate solution having Na2O content of 8%. For studying durability, 10% magnesium sulphate solution was used to immerse the specimens up to a period of 15 weeks during which visual observation, weight changes and strength changes were monitored regularly. Addition of silica fume lowers performance of geopolymer pastes. However, in mortars, addition of silica fume significantly enhanced physico-mechanical properties and durability.
Abstract: The deposition of diamond films on a Si3N4 substrate
is an attractive technique for industrial applications because of the
excellent properties of diamond. Pretreatment of substrate is very
important prior to diamond deposition to promote nucleation and
adhesion between coating and substrate. Deposition of
nanocrystalline diamonds films on silicon nitride substrate have been
carried out by HF-CVD technique using mixture of methane and
hydrogen gases. Different pretreatment of substrate including
chemical etching consists of hot acid etching and basic etching and
mechanical etching were used to study the quality of diamond formed
on the substrate. The structure and morphology of diamond coating
have been studied using X-ray Diffraction (XRD) and Scanning
Electron Microscope (SEM) while diamond film quality has been
characterized using Raman spectroscopy. AFM was used to
investigate the effect of chemical etching and mechanical
pretreatment on the surface roughness of the substrates and the
resultant morphology of nanocrystalline diamond. It was found that
diamond film deposited on as-received, basic etched and grinded
substrate shows the morphology of cauliflower while blasted and
acidic etched substrates produce smooth, continuous diamond film.
However, the Raman investigation did not show any deviation in
quality of diamond film for any pretreatment.
Abstract: Fluency is a skill that, unfortunately, many students
lack. This deficiency causes students to be frustrated with, and
overwhelmed by, the act of reading. However, research suggests that
the repeated reading method may help students to improve their
fluency. This study examines the effects of repeated readings on
student fluency. The study-s overarching question is: What effect do
increases in repeated reading have on reading fluency among middle
school students from diverse backgrounds? More specifically, the
authors examine whether repeated reading improves the fluency,
reading speed, reading-oriented self-esteem, and confidence of
students of diverse academic abilities, socio-economics statuses, and
racial and ethnic backgrounds. To examine these questions the
authors conducted a study using repeated reading strategies with a
sample of students from an urban, middle school in the southeastern
United States. We found that, on average, the use of repeated reading
strategies increased students- fluency, words per minute (wpm)
reading score, reading-oriented self-esteem, and confidence.
Abstract: There is widespread emphasis on reform in the teaching of introductory statistics at the college level. Underpinning this reform is a consensus among educators and practitioners that traditional curricular materials and pedagogical strategies have not been effective in promoting statistical literacy, a competency that is becoming increasingly necessary for effective decision-making and evidence-based practice. This paper explains the historical context of, and rationale for reform-oriented teaching of introductory statistics (at the college level) in the health, social and behavioral sciences (evidence-based disciplines). A firm understanding and appreciation of the basis for change in pedagogical approach is important, in order to facilitate commitment to reform, consensus building on appropriate strategies, and adoption and maintenance of best practices. In essence, reform-oriented pedagogy, in this context, is a function of the interaction among content, pedagogy, technology, and assessment. The challenge is to create an appropriate balance among these domains.
Abstract: In this study, we propose the chaotic cipher combined with Mersenne Twister that is an extremely good pseudo-random number generator for the secure communications. We investigate the Lyapunov exponent of the proposed system, and evaluate the randomness performance by comparing RC4 and the chaotic cipher. In these results, our proposed system gets high chaotic property and more randomness than the conventional ciphers.
Abstract: The purpose of the study is to determine secondary prospective mathematics teachers- views related to using flash animations in mathematics lessons and to reveal how the sample presentations towards different mathematical concepts altered their views. This is a case study involving three secondary prospective mathematics teachers from a state university in Turkey. The data gathered from two semi-structural interviews. Findings revealed that these animations help understand mathematics meaningfully, relate mathematics and real world, visualization, and comprehend the importance of mathematics. The analysis of the data indicated that the sample presentations enhanced participants- views about using flash animations in mathematics lessons.
Abstract: Overhead electrical insulators form an important link in an electric power system. Along with the traditional insulators (i.e. glass and porcelain, etc) presently the polymeric insulators are also used world widely. These polymeric insulators are very sensitive to various environmental parameters such temperature, environmental pollution, UV-radiations, etc. which seriously effect their electrical, chemical and hydrophobic properties. The UV radiation level in the central region of Saudi Arabia is high as compared to the IEC standard for the accelerated aging of the composite insulators. Commonly used suspension type of composite EPDM (Ethylene Propylene Diene Monomer) insulator was subjected to accelerated stress aging as per modified IEC standard simulating the inland arid deserts atmospheric condition and also as per IEC-61109 standard. The hydrophobic characteristics were studied by measuring the contact angle along the insulator surface before and after the accelerated aging of the samples. It was found that EPDM insulator loses it hydrophobic properties proportional to the intensity of UV irradiations and its rate of recovery is also very low as compared to Silicone Rubber insulator.KeywordsEPDM, composite insulators, accelerated aging, hydrophobicity, contact angle.
Abstract: Ontologies play an important role in semantic web
applications and are often developed by different groups and
continues to evolve over time. The knowledge in ontologies changes
very rapidly that make the applications outdated if they continue to
use old versions or unstable if they jump to new versions. Temporal
frames using frame versioning and slot versioning are used to take
care of dynamic nature of the ontologies. The paper proposes new
tags and restructured OWL format enabling the applications to work
with the old or new version of ontologies. Gene Ontology, a very
dynamic ontology, has been used as a case study to explain the OWL
Ontology with Temporal Tags.
Abstract: Reliable water level forecasts are particularly
important for warning against dangerous flood and inundation. The
current study aims at investigating the suitability of the adaptive
network based fuzzy inference system for continuous water level
modeling. A hybrid learning algorithm, which combines the least
square method and the back propagation algorithm, is used to
identify the parameters of the network. For this study, water levels
data are available for a hydrological year of 2002 with a sampling
interval of 1-hour. The number of antecedent water level that should
be included in the input variables is determined by two statistical
methods, i.e. autocorrelation function and partial autocorrelation
function between the variables. Forecasting was done for 1-hour until
12-hour ahead in order to compare the models generalization at
higher horizons. The results demonstrate that the adaptive networkbased
fuzzy inference system model can be applied successfully and
provide high accuracy and reliability for river water level estimation.
In general, the adaptive network-based fuzzy inference system
provides accurate and reliable water level prediction for 1-hour ahead
where the MAPE=1.15% and correlation=0.98 was achieved. Up to
12-hour ahead prediction, the model still shows relatively good
performance where the error of prediction resulted was less than
9.65%. The information gathered from the preliminary results
provide a useful guidance or reference for flood early warning
system design in which the magnitude and the timing of a potential
extreme flood are indicated.
Abstract: The orthogonal processes to shape the triangle steel plate into a equilateral vertical steel are examined by an incremental elasto-plastic finite-element method based on an updated Lagrangian formulation. The highly non-linear problems due to the geometric changes, the inelastic constitutive behavior and the boundary conditions varied with deformation are taken into account in an incremental manner. On the contact boundary, a modified Coulomb friction mode is specially considered. A weighting factor r-minimum is employed to limit the step size of loading increment to linear relation. In particular, selective reduced integration was adopted to formulate the stiffness matrix. The simulated geometries of verticality could clearly demonstrate the vertical processes until unloading. A series of experiments and simulations were performed to validate the formulation in the theory, leading to the development of the computer codes. The whole deformation history and the distribution of stress, strain and thickness during the forming process were obtained by carefully considering the moving boundary condition in the finite-element method. Therefore, this modeling can be used for judging whether a equilateral vertical steel can be shaped successfully. The present work may be expected to improve the understanding of the formation of the equilateral vertical steel.
Abstract: Design of experiments made for correlated the hormonal activity of steroids and their effect on the vaginal structure properties. Vaginal wall consists of distinct layers of cells which strongly differ regarding growth in answer to steroid hormones. The presence study carried out for functional evaluation and sustained replacement effect of the reproductive hormones on the vaginal morphometry in the rabbit. Rabbits were maintained control (Co) or ovariectomized (Ovz) and continuously treated with estradiol (Ovz E) and estradiol mixture with testosterone (Ovz ET). Relative to control rabbits with the distinct tissue distribution pattern, ovariectomized animals displayed declined epithelial thickness and atrophy of the muscularis layer that cause the vaginal wall thinning. Estradiol treatment of Orz rabbits inverted these changes to status of the preovariectomy. Histometric measurements in Ovz ET group completely including of thickness of the epithelial and muscular layers was greater in comparison to that of control animals.