2,167 research outputs found
Hybrid Wireless Network Approach for QoS
Fast improvement of wireless networks has stimulated variety of wireless applications that have been used in number of areas such as commerce, emergency services, military, education, and entertainment. As wireless communication capture popularity, specific research has been devoted to supporting real-time transmission with Quality of Service (QoS) requirements for wireless network applications. At the same time, a wireless hybrid network that combines a mobile wireless ad hoc network (MANET) and a wireless infrastructure network has been considered to be a better option for the next generation wireless networks. By directly implementing resource reservation-based QoS routing for MANETs, hybrids networks inherit invalid reservation and race condition problems in MANETs
Green's Matrix for a Second Order Self-Adjoint Matrix Differential Operator
A systematic construction of the Green's matrix for a second order,
self-adjoint matrix differential operator from the linearly independent
solutions of the corresponding homogeneous differential equation set is carried
out. We follow the general approach of extracting the Green's matrix from the
Green's matrix of the corresponding first order system. This construction is
required in the cases where the differential equation set cannot be turned to
an algebraic equation set via transform techniques.Comment: 19 page
An Image Based Approach of IRIS Recognition for Person Identification using Segmentation Algorithm
A biometric system gives automatic identification of an individual based on a unique feature or characteristic possessed by the individual. Iris recognition system is regarded as the most reliable and accurate biometric identification system available. Also, Iris recognition is considered to be the most reliable and accurate biometric identification system present. Iris recognition system captures an image of an individual’s eye, the iris in the image is then meant for the segmentation and normalization for extracting its features. The performance of iris recognition systems mainly depends on the segmentation. Segmentation is used for the localization of the correct iris region in the particular region of an eye and it should be done accurately and correctly to remove the eyelids, eyelashes, reection and pupil noises present in iris region. Iris images are selected from the Database, then the iris and pupil boundary is detected from rest of the eye image,by removing the noises. The segmented iris region was normalized to compress the dimensional inconsistencies between two iris regions by using Then the features of the iris were encoded by convolving the normalized iris. The Hamming distance was chosen as a matching metric parameter, which gave the measure of how many bits disagreed between the templates of the iris
Effect of Nozzle Divergence Angle on Plume Expansion In Outer-Space Conditions
We carry out numerical simulations to investigate
the effect of nozzle divergence angle on back flow of
plume expansion into rarefied atmosphere.
Results are
obtained using open source compressible computational
fluid dynamics (CFD) solver.
Non-equilibrium slip and
jump boundary conditions for velocity and temperature are
implemented to capture rarefaction rarefaction effects in
the slip flow regime. The solver has been validated with
the experimental data for a nozzle flow in the slip flow
regime. We explore the non-linear non-equilibrium gas flow
physics of a supersonic jet expansion. We report results of
pressure, heat and drag coefficients for different divergent
angles (
12
0
,
15
0
and
20
0
) at 80 km altitude conditions. The
slip based results for heat loads significantly under-predict
the no-slip ones, while for pressure and drag coefficients,
deviations are found to be minute. It is noticed that thrust
coefficient of nozzle increases with increase in divergence
angle, however, nozzle with divergent angle of
15
0
led to
minimum drag and heat transfer load on the critical region.
The current study is important from the perspective of the
overall aero-thermodynamic design of a typical supersonic rocket model operating under rarefied conditions
- …