Abstract: One of the major features of hypermedia learning is its non-linear structure, allowing learners, the opportunity of flexible navigation to accommodate their own needs. Nevertheless, such flexibility can also cause problems such as insufficient navigation and disorientation for some learners, especially those with Field Dependent cognitive styles. As a result students learning performance can be deteriorated and in turn, they can have negative attitudes with hypermedia learning systems. It was suggested that visual elements can be used to compensate dilemmas. However, it is unclear whether these visual elements improve their learning or whether problems still exist. The aim of this study is to investigate the effect of students cognitive styles and visual elements on students learning performance and attitudes in hypermedia learning environment. Cognitive Style Analysis (CSA), Learning outcome in terms of pre and post-test, practical task, and Attitude Questionnaire (AQ) were administered to a sample of 60 university students. The findings revealed that FD students preformed equally to those of FI. Also, FD students experienced more disorientation in the hypermedia learning system where they depend a lot on the visual elements for navigation and orientation purposes. Furthermore, they had more positive attitudes towards the visual elements which escape them from experiencing navigation and disorientation dilemmas. In contrast, FI students were more comfortable, did not get disturbed or did not need some of the visual elements in the hypermedia learning system.
Abstract: Over the early years of the 21st century, cities
throughout the Middle East, particularly in the Gulf region have
expanded more rapidly than ever before. Given the presence of a
large volume of high-rise buildings allover the region, the local
authority aims to set a new standard for sustainable development;
with an integrated approach to maintain a balance between economy,
quality, environmental protection and safety of life. In the very near
future, as mandatory requirements, sustainability will be the criteria
that should be included in all building projects. It is well known in
the building sustainability topics that structural design engineers do
not have a key role in this matter. In addition, the LEED (Leadership
in Energy and Environmental Design) has looked almost exclusively
on the environmental components and materials specifications. The
objective of this paper is to focus and establish groundwork for
sustainability techniques and applications related to the RC high-rise
buildings design, from the structural point of view. A set of
recommendations related to local conditions, structural modeling and
analysis is given, and some helpful suggestions for structural design
team work are addressed. This paper attempts to help structural
engineers in identifying the building sustainability design, in order to
meet local needs and achieve alternative solutions at an early stage of
project design.
Abstract: Grasslands of Iran are encountered with a vast
desertification and destruction. Some legumes are plants of forage
importance with high palatability. Studied legumes in this project are
Onobrychis, Medicago sativa (alfalfa) and Trifolium repens. Seeds
were cultivated in research field of Kaboutarabad (33 km East of
Isfahan, Iran) with an average 80 mm. annual rainfall. Plants were
cultivated in a split plot design with 3 replicate and two water
treatments (weekly irrigation, and under stress with same amount per
15 days interval). Water entrance to each plots were measured by
Partial flow. This project lasted 20 weeks. Destructive samplings
(1m2 each time) were done weekly. At each sampling plants were
gathered and weighed separately for each vegetative parts. An Area
Meter (Vista) was used to measure root surface and leaf area. Total
shoot and root fresh and dry weight, leaf area index and soil coverage
were evaluated too. Dry weight was achieved in 750c oven after 24
hours. Statgraphic and Harvard Graphic software were used to
formulate and demonstrate the parameters curves due to time. Our
results show that Trifolium repens has affected 60 % and Medicago
sativa 18% by water stress. Onobrychis total fresh weight was
reduced 45%. Dry weight or Biomass in alfalfa is not so affected by
water shortage. This means that in alfalfa fields we can decrease the
irrigation amount and have some how same amount of Biomass.
Onobrychis show a drastic decrease in Biomass. The increases in
total dry matter due to time in studied plants are formulated. For
Trifolium repens if removal or cattle entrance to meadows do not
occurred at perfect time, it will decrease the palatability and water
content of the shoots. Water stress in a short period could develop the
root system in Trifolium repens, but if it last more than this other
ecological and soil factors will affect the growth of this plant. Low
level of soil water is not so important for studied legume forges. But
water shortage affect palatability and water content of aerial parts.
Leaf area due to time in studied legumes is formulated. In fact leaf
area is decreased by shortage in available water. Higher leaf area
means higher forage and biomass production. Medicago and
Onobrychis reach to the maximum leaf area sooner than Trifolium
and are able to produce an optimum soil cover and inhibit the
transpiration of soil water of meadows. Correlation of root surface to
Total biomass in studied plants is formulated. Medicago under water
stress show a 40% decrease in crown cover while at optimum
condition this amount reach to 100%. In order to produce forage in
areas without soil erosion Medicago is the best choice even with a
shortage in water resources. It is tried to represent the growth
simulation of three famous Forage Legumes. By growth simulation
farmers and range managers could better decide to choose best plant
adapted to water availability without designing different time and
labor consuming field experiments.
Abstract: In this paper a new robust digital image watermarking
algorithm based on the Complex Wavelet Transform is proposed. This
technique embeds different parts of a watermark into different blocks
of an image under the complex wavelet domain. To increase security
of the method, two chaotic maps are employed, one map is used to
determine the blocks of the host image for watermark embedding,
and another map is used to encrypt the watermark image. Simulation
results are presented to demonstrate the effectiveness of the proposed
algorithm.
Abstract: We propose a phenomenological model for the
process of polymer desorption. In so doing, we omit the usual
theoretical approach of incorporating a fictitious viscoelastic
stress term into the flux equation. As a result, we obtain a
model that captures the essence of the phenomenon of trapping
skinning, while preserving the integrity of the experimentally
verified Fickian law for diffusion. An appropriate asymptotic
analysis is carried out, and a parameter is introduced to represent
the speed of the desorption front. Numerical simulations are
performed to illustrate the desorption dynamics of the model.
Recommendations are made for future modifications of the
model, and provisions are made for the inclusion of experimentally
determined frontal speeds.
Abstract: The use of neural networks for recognition application is generally constrained by their inherent parameters inflexibility after the training phase. This means no adaptation is accommodated for input variations that have any influence on the network parameters. Attempts were made in this work to design a neural network that includes an additional mechanism that adjusts the threshold values according to the input pattern variations. The new approach is based on splitting the whole network into two subnets; main traditional net and a supportive net. The first deals with the required output of trained patterns with predefined settings, while the second tolerates output generation dynamically with tuning capability for any newly applied input. This tuning comes in the form of an adjustment to the threshold values. Two levels of supportive net were studied; one implements an extended additional layer with adjustable neuronal threshold setting mechanism, while the second implements an auxiliary net with traditional architecture performs dynamic adjustment to the threshold value of the main net that is constructed in dual-layer architecture. Experiment results and analysis of the proposed designs have given quite satisfactory conducts. The supportive layer approach achieved over 90% recognition rate, while the multiple network technique shows more effective and acceptable level of recognition. However, this is achieved at the price of network complexity and computation time. Recognition generalization may be also improved by accommodating capabilities involving all the innate structures in conjugation with Intelligence abilities with the needs of further advanced learning phases.
Abstract: The most important subtype of non-Hodgkin-s
lymphoma is the Diffuse Large B-Cell Lymphoma. Approximately
40% of the patients suffering from it respond well to therapy,
whereas the remainder needs a more aggressive treatment, in order to
better their chances of survival. Data Mining techniques have helped
to identify the class of the lymphoma in an efficient manner. Despite
that, thousands of genes should be processed to obtain the results.
This paper presents a comparison of the use of various attribute
selection methods aiming to reduce the number of genes to be
searched, looking for a more effective procedure as a whole.
Abstract: In deregulated operating regime power system security is an issue that needs due thoughtfulness from researchers in the horizon of unbundling of generation and transmission. Electric power systems are exposed to various contingencies. Network contingencies often contribute to overloading of branches, violation of voltages and also leading to problems of security/stability. To maintain the security of the systems, it is desirable to estimate the effect of contingencies and pertinent control measurement can be taken on to improve the system security. This paper presents the application of particle swarm optimization algorithm to find the optimal location of multi type FACTS devices in a power system in order to eliminate or alleviate the line over loads. The optimizations are performed on the parameters, namely the location of the devices, their types, their settings and installation cost of FACTS devices for single and multiple contingencies. TCSC, SVC and UPFC are considered and modeled for steady state analysis. The selection of UPFC and TCSC suitable location uses the criteria on the basis of improved system security. The effectiveness of the proposed method is tested for IEEE 6 bus and IEEE 30 bus test systems.
Abstract: This study aims to assess the potential of solar energy technology for improving access to water and hence the livelihood strategies of rural communities in Baja California Sur, Mexico. It focuses on livestock ranches and photovoltaic water-pumptechnology as well as other water extraction methods. The methodology used are the Sustainable Livelihoods and the Appropriate Technology approaches. A household survey was applied in June of 2006 to 32 ranches in the municipality, of which 22 used PV pumps; and semi-structured interviews were conducted. Findings indicate that solar pumps have in fact helped people improve their quality of life by allowing them to pursue a different livelihood strategy and that improved access to water -not necessarily as more water but as less effort to extract and collect it- does not automatically imply overexploitation of the resource; consumption is based on basic needs as well as on storage and pumping capacity. Justification for such systems lies in the avoidance of logistical problems associated to fossil fuels, PV pumps proved to be the most beneficial when substituting gasoline or diesel equipment but of dubious advantage if intended to replace wind or gravity systems. Solar water pumping technology-s main obstacle to dissemination are high investment and repairs costs and it is therefore not suitable for all cases even when insolation rates and water availability are adequate. In cases where affordability is not an obstacle it has become an important asset that contributes –by means of reduced expenses, less effort and saved time- to the improvement of livestock, the main livelihood provider for these ranches.
Abstract: The radius-of-curvature (ROC) defines the degree of
curvature along the centerline of a roadway whereby a travelling
vehicle must follow. Roadway designs must encompass ROC in
mitigating the cost of earthwork associated with construction while
also allowing vehicles to travel at maximum allowable design speeds.
Thus, a road will tend to follow natural topography where possible,
but curvature must also be optimized to permit fast, but safe vehicle
speeds. The more severe the curvature of the road, the slower the
permissible vehicle speed. For route planning, whether for urban
settings, emergency operations, or even parcel delivery, ROC is a
necessary attribute of road arcs for computing travel time.
It is extremely rare for a geo-spatial database to contain ROC. This
paper will present a procedure and mathematical algorithm to
calculate and assign ROC to a segment pair and/or polyline.
Abstract: The ongoing effort to develop an in-house
compressible solver with multi-disciplinary physics is presented in
this paper. Basic compressible solver combined with IBM technique
provides us an effective numerical tool able to tackle the physics
phenomena and especially physic phenomena involved in Solid
Rocket Motors (SRMs). Main principles are introduced step by step
describing its implementation. This paper sheds light on the whole
potentiality of our proposed numerical model and we strongly believe
a way to introduce multi-physics mechanisms strongly coupled is
opened to ablation in nozzle, fluid/structure interaction and burning
propellant surface with time.
Abstract: Continuously variable transmission (CVT) is a type of
automatic transmission that can change the gear ratio to any arbitrary
setting within the limits. The most common type of CVT operates on
a pulley system that allows an infinite variability between highest and
lowest gears with no discrete steps. However, the current CVT
system with hydraulic actuation method suffers from the power loss.
It needs continuous force for the pulley to clamp the belt and hold the
torque resulting in large amount of energy consumption. This study
focused on the development of an electromechanical actuated control
CVT to eliminate the problem that faced by the existing CVT. It is
conducted with several steps; computing and selecting the
appropriate sizing for stroke length, lead screw system and etc. From
the visual observation it was found that the CVT system of this
research is satisfactory.
Abstract: Fishing has always been an essential component of
the Polynesians- life. Fishhooks, mostly in pearl shell, found during
archaeological excavations are the artifacts related to this activity the
most numerous. Thanks to them, we try to reconstruct the ancient
techniques of resources exploitation, inside the lagoons and offshore.
They can also be used as chronological and cultural indicators. The
shapes and dimensions of these artifacts allow comparisons and
classifications used in both functional approach and chrono-cultural
perspective. Hence it is very important for the ethno-archaeologists
to dispose of reliable methods and standardized measurement of
these artifacts. Such a reliable objective and standardized method
have been previously proposed. But this method cannot be envisaged
manually because of the very important time required to measure
each fishhook manually and the quantity of fishhooks to measure
(many hundreds). We propose in this paper a detailed acquisition
protocol of fishhooks and an automation of every step of this method.
We also provide some experimental results obtained on the fishhooks
coming from three archaeological excavations sites.
Abstract: The excessive use of agricultural pesticides and the
resulting contamination of food and beds of rivers have been a
recurring problem nowadays. Some of these substances can cause
changes in endocrine balance and impair reproductive function of
human and animal population. In the present study, we evaluated the
possible effects of the fungicide cuprous copper oxide Sandoz® on
pregnant Wistar rats. They received a daily oral administration of 103
or 3.103 mg/kg of the fungicide from the 6th to the 15th day of
gestation. On day 21 of gestation, the maternal and fetal toxicity
parameters and indices were determined. The administration of
cuprous oxide (Copper Sandoz) in Wistar rats, the period of
organogenesis, revealed no evidence of maternal toxicity or embryo
at the studied doses.
Abstract: A high-performance Monte Carlo simulation, which
simultaneously takes diffusion-controlled and chain-length-dependent
bimolecular termination reactions into account, is developed to
simulate atom transfer radical copolymerization of styrene and nbutyl
acrylate. As expected, increasing initial feed fraction of styrene
raises the fraction of styrene-styrene dyads (fAA) and reduces that of
n-butyl acrylate dyads (fBB). The trend of variation in randomness
parameter (fAB) during the copolymerization also varies significantly.
Also, there is a drift in copolymer heterogeneity and the highest drift
occurs in the initial feeds containing lower percentages of styrene, i.e.
20% and 5%.
Abstract: In this paper, we study statistical multiplexing of VBR
video in ATM networks. ATM promises to provide high speed realtime
multi-point to central video transmission for telemedicine
applications in rural hospitals and in emergency medical services.
Video coders are known to produce variable bit rate (VBR) signals
and the effects of aggregating these VBR signals need to be
determined in order to design a telemedicine network infrastructure
capable of carrying these signals. We first model the VBR video
signal and simulate it using a generic continuous-data autoregressive
(AR) scheme. We carry out the queueing analysis by the Fluid
Approximation Model (FAM) and the Markov Modulated Poisson
Process (MMPP). The study has shown a trade off: multiplexing
VBR signals reduces burstiness and improves resource utilization,
however, the buffer size needs to be increased with an associated
economic cost. We also show that the MMPP model and the Fluid
Approximation model fit best, respectively, the cell region and the
burst region. Therefore, a hybrid MMPP and FAM completely
characterizes the overall performance of the ATM statistical
multiplexer. The ramifications of this technology are clear: speed,
reliability (lower loss rate and jitter), and increased capacity in video
transmission for telemedicine. With migration to full IP-based
networks still a long way to achieving both high speed and high
quality of service, the proposed ATM architecture will remain of
significant use for telemedicine.
Abstract: Increased energy demand and the concern about
environment friendly technology, renewable bio-fuels are better
alternative to petroleum products. In the present study linseed oil was
used as alternative source for diesel engine fuel and the results were
compared with baseline data of neat diesel. Performance parameters
such as brake thermal efficiency (BTE) and brake specific fuel
consumption (BSFC) and emissions parameters such as CO,
unburned hydro carbon (UBHC), NOx, CO2 and exhaust temperature
were compared. BTE of the engine was lower and BSFC was higher
when the engine was fueled with Linseed oil compared to diesel fuel.
Emission characteristics are better than diesel fuel. NOx formation by
using linseed oil during the experiment was lower than diesel fuel.
Linseed oil is non edible oil, so it can be used as an extender of diesel
fuel energy source for small and medium energy needs.
Abstract: Nowadays, keyless entry systems are widely adopted
for vehicle immobilizer systems due to both advantages of security and
convenience. Keyless entry systems could overcome brute-force key
guessing attack, statistics attack and masquerade attack, however,
they can't prevent from thieves stealing behavior. In this paper, we
proposed a new architecture try to improve the existent flaws. The
integration of the keyless entry system and the fingerprint
identification technology is more suitable to implement on the
portable transponder to achieve higher security needs. We also adopt
and modify AES security protocol for life expectancy and security of
the portable transponder. In addition, the identification of a driver's
fingerprint makes the service of automatic reinstatement of a driver's
preferences become possible. Our design can satisfy not only the three
kinds of previous illegal attacks, but also the stealing situation.
Furthermore, many practical factors, such as costs, life expectancy and
performance, have been well considered in the design of portable
transponder.
Abstract: In this study, the performance of a high-frequency arc
welding machine including a two-switch inverter is analyzed. The
control of the system is achieved using two different control
techniques i- fuzzy logic control (FLC) ii- state space averaging
based sliding control. Fuzzy logic control does not need accurate
mathematical model of a plant and can be used in nonlinear
applications. The second method needs the mathematical model of
the system. In this method the state space equations of the system are
derived for two different “on" and “off" states of the switches. The
derived state equations are combined with the sliding control rule
considering the duty-cycle of the converter. The performance of the
system is analyzed by simulating the system using SIMULINK tool
box of MATLAB. The simulation results show that fuzzy logic
controller is more robust and less sensitive to parameter variations.
Abstract: An experiment was performed in the south of
Morocco in order to evaluate the effect of deficit irrigation by treated
wastewater on chickpea production. We applied six irrigation
treatments on a local variety of chickpea by supplying alternatively
50 or 100% of ETm in a completely randomized design.
We found a highly significant difference between treatments in
terms of biomass production. Drought stress during the vegetative
period showed highest yield with 6.5 t/ha which was more than the
yield obtained for the control (4.9 t/ha). The optimal crop stage in
which deficit irrigation can be applied is the vegetative growth stage,
as the crop has a chance to develop its root system, to be able to
cover the plant needs for water and nutrient supply during the rest of
cycle, and non stress conditions during the flowering and seed filling
stages allow the plant to optimize its photosynthesis and carbon
translocation, therefore increase its productivity.