The chromatic dispersion of fiber is a major factor
causing distortion of the light signals, and if not being
addressed using accurate compensators it will lead to a
significant deterioration in the performance of optical system.
The value of chr
omatic dispersion is not fixed along the fiber,
and this necessitates the use of tunable dispersion
compensators which need information about the value of
dispersion which is done by dispersion monitoring.
This research is Interested in analyzing chromatic
dispersion technique based on the measuring of clock tone
power of transmitted data and which is commensurate with
the dispersion of the fiber. We found the relationship between
signal frequency with range and accuracy of measurement.
Also, the advantage of this technique to provide feedback
signal to tunable dispersion compensator. The results show
the extent of the improvement made in network performance.
VPItransmissionmaker program was used to simulate
the technique proposed.
changing in the ground plane for the fractal antenna has been studied in this research and its effects on the antenna frequency bandwidth for more than frequency bands, results are encouraging, where we get multi band fractal antenna with wide BW for more than 100%.
This research present a novel reconfigurable patch antenna
to support 5G and previous generations frequency bands ,at this
proposed method multi slots have been made in microstrip patch
antenna and three PIN diode at ground The Reconfigurability i
s
done by changing the status (ON - OFF) of the PIN diode on ground
substrate to get butter current distribution on the surface which
led to multiple BW .
In this paper the tracking model in WiMAX Relay Station'
Directional antenna are implemented by OPNET Modeler to Direct
the beam toward users.
this research studies 2x2 MIMO LTE signal transmission from the
main tower eNB and the relay node RN over single mode fiber
using ROF technology and take advantage of the WDM technology,
the results show the ability of ROF to accommodate MIMO
com
munication with high efficiency.
The network has been simulated and analyzed using Optisystem
program, and the results were more than promising.
In this research, tri-band microstrip band pass filter (BPF) has
been designed at frequencies (2.37,3.32 ,5.2)GHz which are
located at the domain of WiMAX and WLAN systems’
application by using tri-section stepped impedance resonators
TSSIRs with
open stub and zero feed line. By changing ratios
of impedance of stepped impedance resonator.
طريقة العناصر المنتهية
مرشح تمرير حزمة شرائحي ثلاثي الحزم
رنانات متدرجة الممانعة ثلاثية المقاطع
مقطع عرضي مفتوح
نسب الممانعة
ضياع الإدخال
tri-band microstrip band pass filter BPf
trisection stepped impedance resonators TSSIRs
open stub
ratios of impedance
finite element method FEM
Insertion loss
المزيد..
This study examines the most important component of NG-PON2
networks and the characteristics of these network through a model of a
system consisting of four pairs of wavelengths to serve 8 subscribers
with symmetrical transmission on both tow links equal to 40Gbps, The
proposed model designed using OptiSystem program shows good
results that give a clear view of the behavior of such systems.
There are many of Formal Methods for testing security protocols detecting being safe
or not. Including Avispa, Casper, ProVerif, Scyther. Previously a comparisons using two
of mentioned methods (ProVerif, Scyther).
In this, research a comparison b
etween the four mentioned methods in terms of the
same used parameters in the previous comparison: working style, the modeling language,
user interface, input, and output. As a result, the user provided with options to choose the
appropriate method depending on the desired parameter.
Six different of security protocols have been tested and finally the results have been
compared; these protocols are Kao Chow Authentication Protocol, 3-D Secure Protocol,
Needham-Schroeder Public Key Protocol, Diffie–Hellman key exchange, Andrew Secure
RPC Protocol, and Challenge Handshake Authentication Protocol
IOT sensors use the publish/subscribe model for communication to benefit from its
decoupled nature with respect to space, time, and synchronization. Because of the
heterogeneity of communicating parties, semantic decoupling is added as a fourth
di
mension. The added semantic decoupling complicates the matching process and reduces
its efficiency. The proposed algorithm clusters subscriptions and events according to topic
and performs the matching process within these clusters, which increases the throughput
by reducing the matching time . Moreover, the accuracy of matching is improved when
subscriptions must be fully approximated . This work shows the benefit of clustering, as
well as the improvement in the matching accuracy and efficiency achieved using this
approach.
Publish/subscribe (pub/sub) is a popular communication paradigm in the design of largescale
distributed systems. We are witnessing an increasingly widespread use of pub/sub
networks for a wide array of applications in industry , academia , financia
l data
dissemination , business process management and does not end in social networking sites
which takes a large area of user interests and used network baseband .
Social network interactions have grown exponentially in recent years to the order of
billions of notifications generated by millions of users every day. So It has become very
important to access in the field of publishing and subscription networks, especially peerto-
peer (P2P) networks that used at first the Scribe data routing protocol. Since then, many
developments and improvements have been made to create new designs. One of these
designs is the Polder Cast protocol.
The research studies most used protocols performance to assess the effectiveness of each in
terms of the speed of the publication and subscription of topic , required resources and
distribution of load .
