Anbar Journal of Engineering Sciences

In this work, a new key exchange protocol for IP-based mobile networks is introduced.
This protocol is called KEPSOM (Key Exchange Protocol Supporting Mobility and
Multihoming). The goals of designing KEPSOM are to develop key exchange protocol
proposal characterized by its secrecy, simplicity, efficiency, resistivity, and its ability to
support mobility and multihoming. The protocol requires only two roundtrips. The design
limits the private information revealed by the initiator. An old security association (SA)
can be replaced with a new one by rekeying without the need of restarting the protocol
with a new session. On the other hand, the changes in IP address due to mobility or
multihoming need not to restart the protocol with a new SA session. The proposed
protocol can also support key exchange in hybrid wireless network, in which the mobile
node can operate in both Ad Hoc and Base Station-oriented wireless network
environments using different transmission modes. KEPSOM has been analyzed and
proven secure. Several tests have been done to measure and evaluate the performance of
the protocol. In these tests, it is found that the required time for rekeying is about 27% of
the total required time for exchanging the keys. And the required time to detect and
update the change in IP address, which may occur due to mobility or multihoming, is less
than 10% of the total required time to establish a new SA sessions.

An experimental investigation is performed to study the friction factor ( f ) and convection
heat transfer coefficient (h) behavior in an asymmetrically heated equilateral triangular
duct by using delta–winglets vortex generators which are embedded in a turbulent
boundary layer. Two side walls of the heated test section are electrically heated with a
constant heat flux, whereas the lower wall is indirectly heated. Reynolds number (Re) is
ranged from (23,000) to (58,000). Two sizes and three attack angles of vortex generators
are studied here for three cases; single, double, and treble pairs of generators. Each pair
was supported in one wall of the test section at the various locations from the leading edge.
The indicated results that friction factor ( f )and Nusselt number (Nu) are relatively
proportion with the size, number and the inclination angle of the generators. The ( f )
decreases as airflow rate increases whereas Nu number increases. The present data of ( f )
is less than the data of Chegini by about (6.5 %) and overpredicts the data of Altemani by
about (1.7 %).

Image compression involves reducing the size of image data file, while retaining necessary
information.This paper uses the facilities of the Genetic Algorithm for the enhancement of the
performance of one of the popular compression method, Vector Quantization method is
selected in this work. After studying this method, new proposed algorithm for mixing the
Genetic Algorithm with this method was constructed and then the required programs for testing
this algorithm was written. The proposed algorithm was tested by applying it on some image
data files. Some fidelity measures are calculated to evaluate the performance of the new
proposed algorithm. A good enhancement was recorded for the performance of the Vector
Quantization method when mixed with the Genetic Algorithm. All programs were written by
using Matlab (version 7.0) and these programs were executed on the Pentium III (866 MHz)
personal computer.

Quantum key distribution (QKD) is a method using some properties of quantum mechanics to
create a secret shared cryptographic key even if an eavesdropper has access to unlimited
computational power. All QKD protocols require that the parties have access to an authentic
channel. Otherwise, QKD is vulnerable to man-in-the-middle attacks. This paper studies QKD
from this point of view, emphasizing the necessity and sufficiency of using unconditionally
secure authentication in QKD. In this work, a new technique of using unconditionally secure
authentication is proposed for quantum cryptosystems. This technique is based on a hybrid of
normal application of authentication codes and the so-called “counter-based” authentication
method such that to achieve a better trade off between security and efficiency (in terms of the
required size of initially shared secret data). Based on this strategy, an authenticated version of a
typical QKD protocol (the well-known BB84 protocol) is described. Some advantages of our
protocol in comparison to other proposals are also highlighted.

A numerical investigation of mixed convection from a horizontal cylinder in a saturated
porous medium is presented. The governing equations based on Darcy’s law are expressed in
a body- fitted coordinate system and solved numerically by explicit method. The direction of
the flow varies between the vertically up ward(assisting flow) and vertically
downward(opposing flow). Results are presented for Reynolds number Re from 10 to 100
with Grashof numbers up to Gr =5Re. The Prandtl number was kept at a constant value of 0.7.
results are presented for the streamlines and isotherms as well as the local and average
Nusselt number at different values of governing parameters. Comparison with previous
theoretical results show good agreement.

The presented work investigates the effect of addition admixtures (superplasticizer and polymer)
to Chopped Worn-Out Tire concrete as a partial replacement of cement weight. Superpasticizer
was addition by 4% and polymer (SBR) by 15%. The Chopped Worn-Out Tire (Ch.W.T.)
addition to reference concrete with the three proportions as a Partial Replacement Ratio (PRR) of
(25,25),(20,30),and (30,20) by volume of (sand and gravel) respectively. Three mixes were
selected with above PRR for each type of admixture in additional to three mixes for Ch.W.T.
concrete without admixtures and three reference mixes with admixtures without Ch.W.T. Thus,
twelve mixes could be used in this investigation. Compressive strength and modulus of elasticity
(static and dynamic) were tested. The test results indicated that the use of admixture led to
significant improvement in concrete properties in general. Superplasticizer gave best results
comparative with polymer, for example at 28 day the compressive strength of superplasticizer
Ch.W.T. concrete Csp25,25 was 32.5 MPa, while compressive strength of polymer modified
Ch.W.T. concrete CB25,25 was 28 MPa and compressive strength of Ch.W.T. concrete C25,25
was 21.2 MPa

Viscoelasticity, as its name implies, is a generalization of elasticity and viscosity. Many
industrial applications use viscoelastic matrix with reinforcement fiber to obtained better
properties. Tensile testing of matrix and one types of fabric polyamide composites was
performed at various loading rates ranging from (8.16* 10-5 to 11.66 * 10-5 m/sec) using a
servohydraulic testing apparatus. The kind of reinforcement, random glass fiber (RGF), and
the kind of matrix, epoxy (E) are used shown that the linear strain (≤ 0.5) for the three
parameter model gives a good agreement with experimental results. The results showed that
both tensile strength and failure strain of these matrices and composites tend to decrease with
increase of strain rate. The experimental results were comparison with numerical results by
using ANSYS 5.4 program for simple study case has shown some agreement. Fracture regions
of the tested specimens were also observed to study micro mechanisms of tensile failure.

The dynamics of wind turbine has to be studied carefully to avoid unpredictable outputs and to
make sure that consistent and efficient power is supplied according to the load requirements.
There is a great and urgent necessity to increase the efforts in the development of the researches
of the renewable energy to decrease the dependency on the conventional ones. The objective of
this research is to make a contribution to the ongoing wind turbine research in the area of
modeling, which is the first step required for the control and implementation of wind turbines.
The wind turbine transfer function is derived and its performance has been established using the
MATHLAB Software. This research provided a different approach to wind turbine modeling
methodology. The results of this research may be used in another step for completing the control
process of the wind turbine.