Abstract: Mobile ad hoc network is a collection of mobile
nodes communicating through wireless channels without any
existing network infrastructure or centralized administration.
Because of the limited transmission range of wireless network
interfaces, multiple "hops" may be needed to exchange data
across the network. Consequently, many routing algorithms
have come into existence to satisfy the needs of
communications in such networks. Researchers have
conducted many simulations comparing the performance of
these routing protocols under various conditions and
constraints. One question that arises is whether speed of nodes
affects the relative performance of routing protocols being
studied. This paper addresses the question by simulating two
routing protocols AODV and DSDV. Protocols were
simulated using the ns-2 and were compared in terms of
packet delivery fraction, normalized routing load and average
delay, while varying number of nodes, and speed.
Abstract: This paper was aimed to survey the level of awareness
of traditional grocery stores in Bangkok in these categories: location,
service quality, risk, shopping, worthwhile, shopping satisfaction, and
future shopping intention. The paper was also aimed to survey factors
influencing the decision to shop at traditional grocery stores in
Bangkok in the future. The findings revealed that consumers had a
high level of awareness of traditional grocery stores in Bangkok.
Consumers were aware that the price was higher and it was riskier to
buy goods and services at traditional grocery stores but they still had
a high level of preference to patronage traditional grocery stores. This
was due to the reasons that there was a high level of satisfaction from
the factors of the friendliness of the owner, the ability to negotiate the
price, the ability to buy on credit, free delivery, and the enjoyment to
meet with other customers in the same neighborhood.
Abstract: The sonochemical decolorization and degradation of azo dye Methyl violet using Fenton-s reagent in the presence of a high-frequency acoustic field has been investigated. Dyeing and textile effluents are the major sources of azo dyes, and are most troublesome among industrial wastewaters, causing imbalance in the eco-system. The effect of various operating conditions (initial concentration of dye, liquid-phase temperature, ultrasonic power and frequency and process time) on sonochemical degradation was investigated. Conversion was found to increase with increase in initial concentration, temperature, power level and frequency. Both horntype and tank-type sonicators were used, at various power levels (250W, 400W and 500W) for frequencies ranging from 20 kHz - 1000 kHz. A 'Process Intensification' parameter PI, was defined to quantify the enhancement of the degradation reaction by ultrasound when compared to control (i.e., without ultrasound). The present work clearly demonstrates that a high-frequency ultrasonic bath can be used to achieve higher process throughput and energy efficiency at a larger scale of operation.
Abstract: Based on the combined shape feature and texture
feature, a fast object detection method with rotation invariant features
is proposed in this paper. A quick template matching scheme based
online learning designed for online applications is also introduced in
this paper. The experimental results have shown that the proposed
approach has the features of lower computation complexity and
higher detection rate, while keeping almost the same performance
compared to the HOG-based method, and can be more suitable for
run time applications.
Abstract: This paper studies mechanical buckling of
functionally graded beams subjected to axial compressive load that is
simply supported at both ends lies on a continuous elastic foundation.
The displacement field of beam is assumed based on Engesser-Timoshenko beam theory. Applying the Hamilton's principle, the
equilibrium equation is established. The influences of dimensionless geometrical parameter, functionally graded index and foundation
coefficient on the critical buckling load of beam are presented. To investigate the accuracy of the present analysis, a compression study
is carried out with a known data.
Abstract: A two-dimensional thin-walled capsule of a flexible
semi-permeable membrane is adhered onto a rigid planar substrate
under adhesive forces (derived from a potential function) in the
presence of osmosis across the membrane. The capsule is immersed
in a hypotonic and diluted binary solution of a non-electrolyte
solute. The Stokes flow problem is solved by the immersed interface
method (IIM) with equal viscosities for the enclosed and
surrounding fluid of the capsule. The numerical results obtained are
verified against two simplified theoretical solutions and the
agreements are good. The osmotic inflation of the adhered capsule is
studied as a function of the solute concentration field, hydraulic
conductivity, and the initial capsule shape. Our findings indicate that
the contact length shrinks in dimension as capsule inflates in the
hypotonic medium, and the equilibrium contact length does not
depend on the hydraulic conductivity of the membrane and the
initial shape of the capsule.
Abstract: The main objective of this work is to compare the
quality of service of the bus companies operating in the city of Rio
Branco, located in the state of Acre with the quality of service of the
bus companies operating in the city of Campos, situated in the state
of Rio de Janeiro, both cities in Brazil. This comparison, based on the
opinion of the bus users, will determine their degree of satisfaction
with the service available in both cities. The outcome of this
evaluation shows the users unhappy with the quality of the service
provided by the bus companies operating in both cities and the need
to identify alternative solutions that may minimize the consequences
caused by the main problems detected in this work. With these
alternatives available, the bus companies will be able to better
understand the needs of their customers in terms of manpower,
service cost, time schedule, etc.
Abstract: Iris pattern is an important biological feature of human body; it becomes very hot topic in both research and practical applications. In this paper, an algorithm is proposed for iris recognition and a simple, efficient and fast method is introduced to extract a set of discriminatory features using first order gradient operator applied on grayscale images. The gradient based features are robust, up to certain extents, against the variations may occur in contrast or brightness of iris image samples; the variations are mostly occur due lightening differences and camera changes. At first, the iris region is located, after that it is remapped to a rectangular area of size 360x60 pixels. Also, a new method is proposed for detecting eyelash and eyelid points; it depends on making image statistical analysis, to mark the eyelash and eyelid as a noise points. In order to cover the features localization (variation), the rectangular iris image is partitioned into N overlapped sub-images (blocks); then from each block a set of different average directional gradient densities values is calculated to be used as texture features vector. The applied gradient operators are taken along the horizontal, vertical and diagonal directions. The low order norms of gradient components were used to establish the feature vector. Euclidean distance based classifier was used as a matching metric for determining the degree of similarity between the features vector extracted from the tested iris image and template features vectors stored in the database. Experimental tests were performed using 2639 iris images from CASIA V4-Interival database, the attained recognition accuracy has reached up to 99.92%.
Abstract: In recent years, there have been attempts to store
natural gas in adsorptive form. This is called adsorptive natural gas,
or ANG. The problem with this technology is the low sorption
capacity. The purpose is to achieve compressed natural gas (CNG)
capacity of 230 V/V. Further research is required to achieve such
target. Several research studies have been performed with this target;
through either the modification or development of new sorbents or
the optimization of the operation sorption process itself. In this work,
storage of methane on molecular sieves 5A and 13X was studied on
dry basis, and on wet basis to certain extent. The temperature and the
pressure dynamics were investigated. The results indicated that
regardless of the charge pressure, the time for the peak temperature
during the methane charge process is always the same. This can be
used as a characteristic of the adsorbent. The total achieved
deliveries using molecular sieves were much lower than that of
activated carbons; 53.0 V/V for the case of 13X molecular sieves and
43 V/V for the case of 5A molecular sieves, both at 2oC and 4 MPa
(580 psi). Investigation of charge pressure dynamic using wet
molecular sieves at 2oC and a mass ratio of 0.5, revealed slowness of
the process and unexpected behavior.
Abstract: Classification of Persian printed numeral characters
has been considered and a proposed system has been introduced. In
representation stage, for the first time in Persian optical character
recognition, extended moment invariants has been utilized as
characters image descriptor. In classification stage, four different
classifiers namely minimum mean distance, nearest neighbor rule,
multi layer perceptron, and fuzzy min-max neural network has been
used, which first and second are traditional nonparametric statistical
classifier. Third is a well-known neural network and forth is a kind of
fuzzy neural network that is based on utilizing hyperbox fuzzy sets.
Set of different experiments has been done and variety of results has
been presented. The results showed that extended moment invariants
are qualified as features to classify Persian printed numeral
characters.
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: 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: 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: This study employs auto-regressive distributed lag (ARDL) bounds approach to cointegration for long run and errorcorrection modeling (ECM) for short run analysis to examine the relationship between revenue gap and economic growth for Pakistan using annual time series data over the period 1980 to 2008. The short and long run results indicate that revenue gap is statistical significant and negatively effect economic growth. The significant and negative coefficient of error correction term in ECM indicates that after a shock, the long rum equilibrium will again converge towards equilibrium about 10.406 percent within a year.
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: A new multi-step comprehensive experience-based
learning program was developed and carried out so that the students
understood about what was the principle of the circuit function and
how the designed circuit was used in actual advanced applications.
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: Transient eddy current problem is solved in the
present paper by the method of the Laplace transform for the case of
a double conductor line located parallel to a conducting half-space.
The Fourier sine and cosine integral transforms are used in order to
find the Laplace transform of the solution. The inverse Laplace
transform of the solution is found in closed form. The integrated
electromotive force per unit length of the double conductor line is
calculated in the form of an improper integral.
Abstract: A collaboration among the Hospital S. Giovanni Battista
of Turin, the Politecnico of Turin, and the MUST company is
described. The content of the collaboration has been and is the use of
ICT-s, e-learning, and blended learning for the internal professional
education, training, and keeping up to date of the personnel of the
hospital. A platform for the delivery of the teaching materials has
been built, including an evaluation and self-evaluation tool. The first
on line courses have been developed and delivered and many more
are in preparation. The first results of the monitoring of the efficacy
of the online education have been positive.
Abstract: Single crystals of Magnesium alloys such as Mg-1Al,
Mg-1Zn-0.5Y, Mg-3Li, and AZ31 alloys were successfully fabricated in this study by employing the modified Bridgman method. Single
crystals of pure Mg were also made in this study. To determine the exact orientation of crystals, Laue back-reflection method and pole figure measurement were carried out on each single crystal. Dimensions of single crystals were 10 mm in diameter and 120 mm in
length. Hardness and compression tests were conducted and the results
revealed that hardness and the strength strongly depended on the
orientation. The closer to basal one the orientation was, the higher hardness and compressive strength were. The effect of alloying was
not higher than that of orientation. After compressive deformation of single crystals, the orientation of the crystals was found to rotate and to be parallel to the basal orientation.