Abstract: Continuation of an active call is one of the most important quality measurements in the cellular systems. Handoff process enables a cellular system to provide such a facility by transferring an active call from one cell to another. Different approaches are proposed and applied in order to achieve better handoff service. The principal parameters used to evaluate handoff techniques are: forced termination probability and call blocking probability. The mechanisms such as guard channels and queuing handoff calls decrease the forced termination probability while increasing the call blocking probability. In this paper we present an overview about the issues related to handoff initiation and decision and discuss about different types of handoff techniques available in the literature.
Abstract: With the exponential progress of technological
development comes a strong sense that events are moving too quickly
for our schools and that teachers may be losing control of them in the
process. This paper examines the impact of e-learning and e-teaching
in universities, from both the student and teacher perspective. In
particular, it is shown that e-teachers should focus not only on the
technical capacities and functions of IT materials and activities, but
must attempt to more fully understand how their e-learners perceive
the learning environment. From the e-learner perspective, this paper
indicates that simply having IT tools available does not automatically
translate into all students becoming effective learners. More
evidence-based evaluative research is needed to allow e-learning and
e-teaching to reach full potential.
Abstract: The peculiarities of the nanoscale structure-phase
states formed after electroexplosive carburizing and subsequent
electron-beam treatment of technically pure titanium surface in different regimes are established by methods of transmission electron
diffraction microscopy and physical mechanisms are discussed. Electroexplosive carburizing leads to surface layer formation
(40 m thickness) with increased (in 3.5 times) microhardness. It consists of β-titanium, graphite (monocrystals 100-150 nm,
polycrystals 5-10 nm, amorphous particles 3-5nm), TiC (5-10 nm), β-Ti02 (2-20nm). After electron-beam treatment additionally increasing the microhardness the surface layer consists of TiC.
Abstract: Biodiesel as an alternative fuel for diesel engines has been developed for some three decades now. While it is gaining wide acceptance in Europe, USA and some parts of Asia, the same cannot be said of Africa. With more than 35 countries in the continent depending on imported crude oil, it is necessary to look for alternative fuels which can be produced from resources available locally within any country. Hence this study presents performance of single cylinder diesel engine using blends of shea butter biodiesel. Shea butter was transformed into biodiesel by transesterification process. Tests are conducted to compare the biodiesel with baseline diesel fuel in terms of engine performance and exhaust emission characteristics. The results obtained showed that the addition of biodiesel to diesel fuel decreases the brake thermal efficiency (BTE) and increases the brake specific fuel consumption (BSFC). These results are expected due to the lower energy content of biodiesel fuel. On the other hand while the NOx emissions increased with increase in biodiesel content in the fuel blends, the emissions of carbon monoxide (CO), un-burnt hydrocarbon (UHC) and smoke opacity decreased. The engine performance which indicates that the biodiesel has properties and characteristics similar to diesel fuel and the reductions in exhaust emissions make shea butter biodiesel a viable additive or substitute to diesel fuel.
Abstract: Repetitive systems stand for a kind of systems that
perform a simple task on a fixed pattern repetitively, which are
widely spread in industrial fields. Hence, many researchers have been
interested in those systems, especially in the field of iterative learning
control (ILC). In this paper, we propose a finite-horizon tracking
control scheme for linear time-varying repetitive systems with uncertain
initial conditions. The scheme is derived both analytically
and numerically for state-feedback systems and only numerically for
output-feedback systems. Then, it is extended to stable systems with
input constraints. All numerical schemes are developed in the forms
of linear matrix inequalities (LMIs). A distinguished feature of the
proposed scheme from the existing iterative learning control is that
the scheme guarantees the tracking performance exactly even under
uncertain initial conditions. The simulation results demonstrate the
good performance of the proposed scheme.
Abstract: A high-frequency low-power sinusoidal quadrature
oscillator is presented through the use of two 2nd-order low-pass
current-mirror (CM)-based filters, a 1st-order CM low-pass filter and
a CM bilinear transfer function. The technique is relatively simple
based on (i) inherent time constants of current mirrors, i.e. the
internal capacitances and the transconductance of a diode-connected
NMOS, (ii) a simple negative resistance RN formed by a resistor load
RL of a current mirror. Neither external capacitances nor inductances
are required. As a particular example, a 1.9-GHz, 0.45-mW, 2-V
CMOS low-pass-filter-based all-current-mirror sinusoidal quadrature
oscillator is demonstrated. The oscillation frequency (f0) is 1.9 GHz
and is current-tunable over a range of 370 MHz or 21.6 %. The
power consumption is at approximately 0.45 mW. The amplitude
matching and the quadrature phase matching are better than 0.05 dB
and 0.15°, respectively. Total harmonic distortions (THD) are less
than 0.3 %. At 2 MHz offset from the 1.9 GHz, the carrier to noise
ratio (CNR) is 90.01 dBc/Hz whilst the figure of merit called a
normalized carrier-to-noise ratio (CNRnorm) is 153.03 dBc/Hz. The
ratio of the oscillation frequency (f0) to the unity-gain frequency (fT)
of a transistor is 0.25. Comparisons to other approaches are also
included.
Abstract: Background: This investigated the mental health of the elderly survivors six months, ten months and two years after the “5.12 Wenchuan" earthquake. Methods: Two hundred and thirty-two physically healthy older survivors from earthquake-affected Mianyang County were interviewed. The measures included the Revised Impact of Event Scale (IES-R, Chinese version, for PTSD) and a Chinese Mental Health Inventory for the Elderly (MHIE). A repeated measures ANOVA test was used for statistical analysis. Results: The follow-up group had a statistically significant lower IES-R score and lower MHIE score than the initial group ten months after the earthquake. Two years later, the score of IES-R in follow-up group were still lower than that of non-follow-up group, but no differences were significant on the score of MHIE between groups. Furthermore, a negative relationship was found between scores of IES-R and MHIE. Conclusion: The earthquake has had a persistent negative impact on older survivors- mental health within the two-year period and that although the PTSD level declined significantly with time, it did not disappear completely.
Abstract: This paper presents a new method of analog fault diagnosis based on back-propagation neural networks (BPNNs) using wavelet decomposition and fractal dimension as preprocessors. The proposed method has the capability to detect and identify faulty components in an analog electronic circuit with tolerance by analyzing its impulse response. Using wavelet decomposition to preprocess the impulse response drastically de-noises the inputs to the neural network. The second preprocessing by fractal dimension can extract unique features, which are the fed to a neural network as inputs for further classification. A comparison of our work with [1] and [6], which also employs back-propagation (BP) neural networks, reveals that our system requires a much smaller network and performs significantly better in fault diagnosis of analog circuits due to our proposed preprocessing techniques.
Abstract: Information on weed distribution within the field is necessary to implement spatially variable herbicide application. Since hand labor is costly, an automated weed control system could be feasible. This paper deals with the development of an algorithm for real time specific weed recognition system based on Histogram Maxima with threshold of an image that is used for the weed classification. This algorithm is specifically developed to classify images into broad and narrow class for real-time selective herbicide application. The developed system has been tested on weeds in the lab, which have shown that the system to be very effectiveness in weed identification. Further the results show a very reliable performance on images of weeds taken under varying field conditions. The analysis of the results shows over 95 percent classification accuracy over 140 sample images (broad and narrow) with 70 samples from each category of weeds.
Abstract: A four-lobe pressure dam bearing which is
produced by cutting two pressure dams on the upper two lobes and
two relief-tracks on the lower two lobes of an ordinary four-lobe
bearing is found to be more stable than a conventional four-lobe
bearing. In this paper a four-lobe pressure dam bearing supporting
rigid and flexible rotors is analytically investigated to determine its
performance when L/D ratio is varied in the range 0.75 to 1.5. The
static and dynamic characteristics are studied at various L/D ratios.
The results show that the stability of a four-lobe pressure dam
bearing increases with decrease in L/D ratios both for rigid as well as
flexible rotors.
Abstract: The aim of this study is to determine the effect of
strategic management implementations on the institutionalization
levels. In this regard a field study has been made over 31 stone quarry
enterprises in cement producing sector in Konya by using survey
method. In this study, institutionalization levels of the enterprises
have been evaluated regarding three dimensions: professionalization,
management approach, participation in decisions and delegation of
authority. According to the results of the survey, there is a highly
positive and statistically significant relationship between the strategic
management implementations and institutionalization levels of the
enterprises. Additionally,-considering the results of regression
analysis made for establishing the relationship between strategic
management and institutionalization levels- it has been determined
that strategic management implementations of the enterprises can be
used as a variable to explain the institutionalization levels of them,
and also strategic management implementations of the enterprises
increase the institutionalization levels of them.
Abstract: The problem of laminar fluid flow which results from
the shrinking of a permeable surface in a nanofluid has been
investigated numerically. The model used for the nanofluid
incorporates the effects of Brownian motion and thermophoresis. A
similarity solution is presented which depends on the mass suction
parameter S, Prandtl number Pr, Lewis number Le, Brownian motion
number Nb and thermophoresis number Nt. It was found that the
reduced Nusselt number is decreasing function of each dimensionless
number.
Abstract: This study sought to determine whether there were relationships existed among leisure satisfaction, self-esteem, and spiritual wellness. Four hundred survey instruments were distributed, and 334 effective instruments were returned, for an effective rate of 83.5%. The participants were recruited from a purposive sampling that subjects were at least 60 years of age and retired in Tainan City, Taiwan. Three instruments were used in this research: Leisure Satisfaction Scale (LSS), Self-Esteem Scale (SES), and Spirituality Assessment Scale (SAS). The collected data were analyzed statistically. The findings of this research were as follows: 1. There is significantly correlated between leisure satisfaction and spiritual wellness. 2. There is significantly correlated between leisure satisfaction and self-esteem. 3. There is significantly correlated between spiritual wellness and self-esteem.
Abstract: Undoubtedly, chassis is one of the most important
parts of a vehicle. Chassis that today are produced for vehicles are
made up of four parts. These parts are jointed together by screwing.
Transverse parts are called cross member.
This study reviews the stress generated by cyclic laboratory loads
in front cross member of Peugeot 405. In this paper the finite element
method is used to simulate the welding process and to determine the
physical response of the spot-welded joints. Analysis is done by the
Abaqus software.
The Stresses generated in cross member structure are generally
classified into two groups: The stresses remained in form of residual
stresses after welding process and the mechanical stress generated by
cyclic load. Accordingly the total stress must be obtained by
determining residual stress and mechanical stress separately and then
sum them according to the superposition principle.
In order to improve accuracy, material properties including
physical, thermal and mechanical properties were supposed to be
temperature-dependent. Simulation shows that maximum Von Misses
stresses are located at special points. The model results are then
compared to the experimental results which are reported by
producing factory and good agreement is observed.
Abstract: Color constancy algorithms are generally based on the
simplified assumption about the spectral distribution or the reflection
attributes of the scene surface. However, in reality, these assumptions
are too restrictive. The methodology is proposed to extend existing
algorithm to applying color constancy locally to image patches rather
than globally to the entire images.
In this paper, a method based on low-level image features using
superpixels is proposed. Superpixel segmentation partition an image
into regions that are approximately uniform in size and shape. Instead
of using entire pixel set for estimating the illuminant, only superpixels
with the most valuable information are used. Based on large scale
experiments on real-world scenes, it can be derived that the estimation
is more accurate using superpixels than when using the entire image.
Abstract: In this paper, a new technique for fast painting with
different colors is presented. The idea of painting relies on applying
masks with different colors to the background. Fast painting is
achieved by applying these masks in the frequency domain instead of
spatial (time) domain. New colors can be generated automatically as a
result from the cross correlation operation. This idea was applied
successfully for faster specific data (face, object, pattern, and code)
detection using neural algorithms. Here, instead of performing cross
correlation between the input input data (e.g., image, or a stream of
sequential data) and the weights of neural networks, the cross
correlation is performed between the colored masks and the
background. Furthermore, this approach is developed to reduce the
computation steps required by the painting operation. The principle of
divide and conquer strategy is applied through background
decomposition. Each background is divided into small in size subbackgrounds
and then each sub-background is processed separately by
using a single faster painting algorithm. Moreover, the fastest painting
is achieved by using parallel processing techniques to paint the
resulting sub-backgrounds using the same number of faster painting
algorithms. In contrast to using only faster painting algorithm, the
speed up ratio is increased with the size of the background when using
faster painting algorithm and background decomposition. Simulation
results show that painting in the frequency domain is faster than that in
the spatial domain.
Abstract: Artificial Neural Network (ANN) has been
extensively used for classification of heart sounds for its
discriminative training ability and easy implementation. However, it
suffers from overparameterization if the number of nodes is not
chosen properly. In such cases, when the dataset has redundancy
within it, ANN is trained along with this redundant information that
results in poor validation. Also a larger network means more
computational expense resulting more hardware and time related
cost. Therefore, an optimum design of neural network is needed
towards real-time detection of pathological patterns, if any from heart
sound signal. The aims of this work are to (i) select a set of input
features that are effective for identification of heart sound signals and
(ii) make certain optimum selection of nodes in the hidden layer for a
more effective ANN structure. Here, we present an optimization
technique that involves Singular Value Decomposition (SVD) and
QR factorization with column pivoting (QRcp) methodology to
optimize empirically chosen over-parameterized ANN structure.
Input nodes present in ANN structure is optimized by SVD followed
by QRcp while only SVD is required to prune undesirable hidden
nodes. The result is presented for classifying 12 common
pathological cases and normal heart sound.
Abstract: In the paper, the results of sensitivity analysis of the influence of initial imperfections on the web stress state of a thinwalled girder are presented. The results of the study corroborate a very good and effective agreement of experiments with theory. Most input random quantities were found experimentally. The change of sensitivity coefficients in dependence on working load value is analysed. The stress was analysed by means of a geometrically and materially non-linear solution by applying the program ANSYS. This research study offers important background for theoretical studies of stability problems, post-critical effects and limit states of thin-walled steel structures.
Abstract: Development of cities and villages, agricultural farms
and industrial regions in abutment and/or in the course of streams and
rivers or in prone flood lands has been caused more notations in
hydrology problems and city planning topics. In order to protection
of cities against of flood damages, embankment construction is a
desired and scientific method. The cities that located in arid zones
may damage by floods periodically. Zavvareh city in Ardestan
township(Isfahan province) with 7704 people located in Ardestan
plain that has been damaged by floods that have flowed from
dominant mountainous watersheds in past years with regard to return
period. In this study, according to flowed floods toward Zavvareh
city, was attempt to plan suitable hydraulic structures such as canals,
bridges and collectors in order to collection, conduction and
depletion of city surface runoff.
Abstract: Cloud Computing (CC) has become one of the most
talked about emerging technologies that provides powerful
computing and large storage environments through the use of the
Internet. Cloud computing provides different dynamically scalable
computing resources as a service. It brings economic benefits to
individuals and businesses that adopt the technology. In theory
adoption of cloud computing reduces capital and operational
expenditure on information technology. For this to be a reality there
is need to solve some challenges and at the same time addressing
concerns that consumers have about cloud computing. This paper
looks at Cloud Computing in general then highlights the challenges
of Cloud Computing and finally suggests solutions to some of the
challenges.