Abstract: This paper is introduced a modification to Diffie-
Hellman protocol to be applicable on the decimal numbers, which
they are the numbers between zero and one. For this purpose we
extend the theory of the congruence. The new congruence is over
the set of the real numbers and it is called the “real congruence"
or the “real modulus". We will refer to the existing congruence by
the “integer congruence" or the “integer modulus". This extension
will define new terms and redefine the existing terms. As the
properties and the theorems of the integer modulus are extended as
well. Modified Diffie-Hellman key exchange protocol is produced a
sharing, secure and decimal secret key for the the cryptosystems that
depend on decimal numbers.
Abstract: This study deals with Computational Fluid Dynamics
(CFD) studies of the interactions between the air flow and louvered
fins which equipped the automotive heat exchangers. 3D numerical
simulation results are obtained by using the ANSYS Fluent 13.0 code
and compared to experimental data. The paper studies the effect of
louver angle and louver pitch geometrical parameters, on overall
thermal hydraulic performances of louvered fins.
The comparison between CFD simulations and experimental data
show that established 3-D CFD model gives a good agreement. The
validation agrees, with about 7% of deviation respectively of friction
and Colburn factors to experimental results. As first, it is found that
the louver angle has a strong influence on the heat transfer rate. Then,
louver angle and louver pitch variation of the louvers and their effects
on thermal hydraulic performances are studied. In addition to this
study, it is shown that the second half of the fin takes has a
significant contribution on pressure drop increase without any
increase in heat transfer.
Abstract: Maintenance costs incurred on building differs. The
difference can be as results of the types, functions, age, building
health index, size, form height, location and complexity of the
building. These are contributing to the difficulty in maintenance
development of deterministic maintenance cost model. This paper is
concerns with reporting the preliminary findings on the creation of
building maintenance cost distributions for universities in Malaysia.
This study is triggered by the need to provide guides on maintenance
costs distributions for decision making. For this purpose, a survey
questionnaire was conducted to investigate the distribution of
maintenance costs in the universities. Altogether, responses were
received from twenty universities comprising both private and
publicly owned. The research found that engineering services,
roofing and finishes were the elements contributing the larger
segment of the maintenance costs. Furthermore, the study indicates
the significance of maintenance cost distribution as decision making
tool towards maintenance management.
Abstract: Cameron Highlands is known for upland tourism area
with vast natural wealth, mountainous landscape endowed with rich
diverse species as well as people traditions and cultures. With these
various resources, CH possesses an interesting visual and panorama
that can be offered to the tourist. However this benefit may not be
utilized without obtaining the understanding of existing landscape
structure and visual. Given a limited data, this paper attempts to
classify landscape visual of Cameron Highlands using land use and
contour data. Visual points of view were determined from the given
tourist attraction points in the CH Local Plan 2003-2015. The result
shows landscape visual and structure categories offered in the study
area. The result can be used for further analysis to determine the best
alternative tourist trails for tourism planning and decision making
using readily available data.
Abstract: The production of ethyl tert-butyl ether (ETBE) was
simulated through Aspen Plus. The objective of this work was to use
the simulation results to be an alternative platform for ETBE
production from naphtha cracking wastes for the industry to develop.
ETBE is produced from isobutylene which is one of the wastes in
naphtha cracking process. The content of isobutylene in the waste is
less than 30% weight. The main part of this work was to propose a
process to save the environment and to increase the product value by
converting a great majority of the wastes into ETBE. Various
processes were considered to determine the optimal production of
ETBE. The proposed process increased ETBE production yield by
100% from conventional process with the purity of 96% weight. The
results showed a great promise for developing this proposed process
in an industrial scale.
Abstract: Trihalomethanes (THMs) were among the first
disinfection byproducts to be discovered in chlorinated water. The
substances form during a reaction between chlorine and organic
matter in the water. Trihalomethanes are suspected to have negative
effects on birth such as, low birth weight, intrauterine growth
retardation in term births, as well as gestational age and preterm
delivery. There are also some evidences showing these by-products to
be mutagenic and carcinogenic, the greatest amount of evidence being
related to the bladder cancer. However, there exist inconsistencies
regarding such effects of THMs as different studies have provided
different results in this regard. The aim of the present study is to
provide a review of the related researches about the above mentioned
health effects of THMs.
Abstract: A transient finite element model has been developed
to study the heat transfer and fluid flow during spot Gas Tungsten
Arc Welding (GTAW) on stainless steel. Temperature field, fluid
velocity and electromagnetic fields are computed inside the cathode,
arc-plasma and anode using a unified MHD formulation. The
developed model is then used to study the influence of different
helium-argon gas mixtures on both the energy transferred to the
workpiece and the time evolution of the weld pool dimensions. It is
found that the addition of helium to argon increases the heat flux
density on the weld axis by a factor that can reach 6.5. This induces
an increase in the weld pool depth by a factor of 3. It is also found
that the addition of only 10% of argon to helium decreases
considerably the weld pool depth, which is due to the electrical
conductivity of the mixture that increases significantly when argon is
added to helium.
Abstract: The prevalence of non organic constipation differs
from country to country and the reliability of the estimate rates is
uncertain. Moreover, the clinical relevance of subdividing the
heterogeneous functional constipation disorders into pre-defined
subgroups is largely unknown.. Aim: to estimate the prevalence of
constipation in a population-based sample and determine whether
clinical subgroups can be identified. An age and gender stratified
sample population from 5 Italian cities was evaluated using a
previously validated questionnaire. Data mining by cluster analysis
was used to determine constipation subgroups. Results: 1,500
complete interviews were obtained from 2,083 contacted households
(72%). Self-reported constipation correlated poorly with symptombased
constipation found in 496 subjects (33.1%). Cluster analysis
identified four constipation subgroups which correlated to subgroups
identified according to pre-defined symptom criteria. Significant
differences in socio-demographics and lifestyle were observed
among subgroups.
Abstract: TUSAT is a prospective Turkish
Communication Satellite designed for providing mainly data
communication and broadcasting services through Ku-Band
and C-Band channels. Thermal control is a vital issue in
satellite design process. Therefore, all satellite subsystems and
equipments should be maintained in the desired temperature
range from launch to end of maneuvering life. The main
function of the thermal control is to keep the equipments and
the satellite structures in a given temperature range for various
phases and operating modes of spacecraft during its lifetime.
This paper describes the thermal control design which uses
passive and active thermal control concepts. The active
thermal control is based on heaters regulated by software via
thermistors. Alternatively passive thermal control composes of
heat pipes, multilayer insulation (MLI) blankets, radiators,
paints and surface finishes maintaining temperature level of
the overall carrier components within an acceptable value.
Thermal control design is supported by thermal analysis using
thermal mathematical models (TMM).
Abstract: Least Significant Bit (LSB) technique is the earliest
developed technique in watermarking and it is also the most simple,
direct and common technique. It essentially involves embedding the
watermark by replacing the least significant bit of the image data with
a bit of the watermark data. The disadvantage of LSB is that it is not
robust against attacks. In this study intermediate significant bit (ISB)
has been used in order to improve the robustness of the watermarking
system. The aim of this model is to replace the watermarked image
pixels by new pixels that can protect the watermark data against
attacks and at the same time keeping the new pixels very close to the
original pixels in order to protect the quality of watermarked image.
The technique is based on testing the value of the watermark pixel
according to the range of each bit-plane.
Abstract: This paper deals with the helical flow of a Newtonian
fluid in an infinite circular cylinder, due to both longitudinal and
rotational shear stress. The velocity field and the resulting shear
stress are determined by means of the Laplace and finite Hankel
transforms and satisfy all imposed initial and boundary conditions.
For large times, these solutions reduce to the well-known steady-state
solutions.
Abstract: In the present work, we propose a new technique to
enhance the learning capabilities and reduce the computation
intensity of a competitive learning multi-layered neural network
using the K-means clustering algorithm. The proposed model use
multi-layered network architecture with a back propagation learning
mechanism. The K-means algorithm is first applied to the training
dataset to reduce the amount of samples to be presented to the neural
network, by automatically selecting an optimal set of samples. The
obtained results demonstrate that the proposed technique performs
exceptionally in terms of both accuracy and computation time when
applied to the KDD99 dataset compared to a standard learning
schema that use the full dataset.
Abstract: This paper simulates the ad-hoc mesh network in rural areas, where such networks receive great attention due to their cost, since installing the infrastructure for regular networks in these areas is not possible due to the high cost. The distance between the communicating nodes is the most obstacles that the ad-hoc mesh network will face. For example, in Terranet technology, two nodes can communicate if they are only one kilometer far from each other. However, if the distance between them is more than one kilometer, then each node in the ad-hoc mesh networks has to act as a router that forwards the data it receives to other nodes. In this paper, we try to find the critical number of nodes which makes the network fully connected in a particular area, and then propose a method to enhance the intermediate node to accept to be a router to forward the data from the sender to the receiver. Much work was done on technological changes on peer to peer networks, but the focus of this paper will be on another feature which is to find the minimum number of nodes needed for a particular area to be fully connected and then to enhance the users to switch on their phones and accept to work as a router for other nodes. Our method raises the successful calls to 81.5% out of 100% attempt calls.
Abstract: Ultrathin (UTD) and Nanoscale (NSD) SOI-MOSFET devices, sharing a similar W/L but with a channel thickness of 46nm and 1.6nm respectively, were fabricated using a selective “gate recessed” process on the same silicon wafer. The electrical transport characterization at room temperature has shown a large difference between the two kinds of devices and has been interpreted in terms of a huge unexpected series resistance. Electrical characteristics of the Nanoscale device, taken in the linear region, can be analytically derived from the ultrathin device ones. A comparison of the structure and composition of the layers, using advanced techniques such as Focused Ion Beam (FIB) and High Resolution TEM (HRTEM) coupled with Energy Dispersive X-ray Spectroscopy (EDS), contributes an explanation as to the difference of transport between the devices.
Abstract: Soil stabilization has been widely used to improve
soil strength and durability or to prevent erosion and dust generation.
Generally to reduce problems of clayey soils in engineering work and
to stabilize these soils additional materials are used. The most
common materials are lime, fly ash and cement. Using this materials,
although improve soil property , but in some cases due to financial
problems and the need to use special equipment are limited .One of
the best methods for stabilization clayey soils is neutralization the
clay particles. For this purpose we can use ion exchange materials.
Ion exchange solution like CBR plus can be used for soil
stabilization. One of the most important things in using CBR plus is
determination the amount of this solution for various soils with
different properties. In this study a laboratory experiment is conduct
to evaluate the ion exchange capacity of three soils with various
plasticity index (PI) to determine amount or required CBR plus
solution for soil stabilization.
Abstract: The knowledge base of welding defect recognition is
essentially incomplete. This characteristic determines that the recognition results do not reflect the actual situation. It also has a further influence on the classification of welding quality. This paper is
concerned with the study of a rough set based method to reduce the influence and improve the classification accuracy. At first, a rough set
model of welding quality intelligent classification has been built. Both condition and decision attributes have been specified. Later on, groups
of the representative multiple compound defects have been chosen
from the defect library and then classified correctly to form the
decision table. Finally, the redundant information of the decision table has been reducted and the optimal decision rules have been reached. By this method, we are able to reclassify the misclassified defects to
the right quality level. Compared with the ordinary ones, this method
has higher accuracy and better robustness.
Abstract: Wind farms (WFs) with high level of penetration are
being established in power systems worldwide more rapidly than
other renewable resources. The Independent System Operator (ISO),
as a policy maker, should propose appropriate places for WF
installation in order to maximize the benefits for the investors. There
is also a possibility of congestion relief using the new installation of
WFs which should be taken into account by the ISO when proposing
the locations for WF installation. In this context, efficient wind farm
(WF) placement method is proposed in order to reduce burdens on
congested lines. Since the wind speed is a random variable and load
forecasts also contain uncertainties, probabilistic approaches are used
for this type of study. AC probabilistic optimal power flow (P-OPF)
is formulated and solved using Monte Carlo Simulations (MCS). In
order to reduce computation time, point estimate methods (PEM) are
introduced as efficient alternative for time-demanding MCS.
Subsequently, WF optimal placement is determined using generation
shift distribution factors (GSDF) considering a new parameter
entitled, wind availability factor (WAF). In order to obtain more
realistic results, N-1 contingency analysis is employed to find the
optimal size of WF, by means of line outage distribution factors
(LODF). The IEEE 30-bus test system is used to show and compare
the accuracy of proposed methodology.
Abstract: In this paper, the problem of stability analysis for a class of impulsive stochastic fuzzy neural networks with timevarying delays and reaction-diffusion is considered. By utilizing suitable Lyapunov-Krasovskii funcational, the inequality technique and stochastic analysis technique, some sufficient conditions ensuring global exponential stability of equilibrium point for impulsive stochastic fuzzy cellular neural networks with time-varying delays and diffusion are obtained. In particular, the estimate of the exponential convergence rate is also provided, which depends on system parameters, diffusion effect and impulsive disturbed intention. It is believed that these results are significant and useful for the design and applications of fuzzy neural networks. An example is given to show the effectiveness of the obtained results.
Abstract: This paper proposes a new optimization techniques
for the optimization a gas processing plant uncertain feed and
product flows. The problem is first formulated using a continuous
linear deterministic approach. Subsequently, the single and joint
chance constraint models for steady state process with timedependent
uncertainties have been developed. The solution approach
is based on converting the probabilistic problems into their
equivalent deterministic form and solved at different confidence
levels Case study for a real plant operation has been used to
effectively implement the proposed model. The optimization results
indicate that prior decision has to be made for in-operating plant
under uncertain feed and product flows by satisfying all the
constraints at 95% confidence level for single chance constrained and
85% confidence level for joint chance constrained optimizations
cases.
Abstract: The atmospheric pressure plasma torch with a direct
current arc discharge stabilized by water vapor vortex was
experimentally investigated. Overheated up to 450K water vapor was
used as plasma forming gas. Plasma torch design is one of the most
important factors leading to a stable operation of the device. The
electrical and thermal characteristics of the plasma torch were
determined during the experimental investigations. The design and
the basic characteristics of the water vapor plasma torch are presented
in the paper.
Plasma torches with the electric arc stabilized by water vapor
vortex provide special performance characteristics in some plasma
processing applications such as thermal plasma neutralization and
destruction of organic wastes enabling to extract high caloric value
synthesis gas as by-product of the process. Syngas could be used as a
surrogate fuel partly replacing the dependence on the fossil fuels or
used as a feedstock for hydrogen, methanol production.