Information centric networking (ICN) is the next generation of internet architecture with its ability to provide in-network caching that make users retrieve their data efficiently regardless of their location. In ICN, security is applied to data itself rather than communication channels or devices. In-network caches are vulnerable to many types of attacks, such as cache poisoning attacks, cache privacy attacks, and cache pollution attacks (CPA). An attacker floods non-popular content to the network and makes the caches evict popular ones. As a result, the cache hit ratio for legitimate users will suffer from a performance degradation and an increase in the content’s retrieval latency. In this paper, a popularity variation mechanism in a CCN-SDN environment (PV-CSDN) is proposed to detect and mitigate CPA. PV-CSDN is based on observing the behavior of legitimate users to learn the normal traffic pattern and record the required threshold values. Two key parameters are used to achieve the threshold values: the popularity of the contents and the average rate of repeated requests for each interface in the router. The current traffic pattern will be compared with the predefined thresholds and if any variation in the traffic is occurred the attack is detected. The algorithm was able to detect the attack, and as a mitigation process, the controller will block the malicious interface to prevent any further degradation in the performance. The experiments show that PV-CSD detects and prevents the attack effectively.
Inelastic longitudinal electron scattering form factors have been calculated for isoscaler transition
T = 0 of the (0+ ®2+ ) and (0+ ®4+ ) transitions for the 20Ne ,24Mg and 28Si nuclei. Model
space wave function defined by the orbits 1d5 2 ,2s1 2 and 1d3 2 can not give reasonable result for
the form factor. The core-polarization effects are evaluated by adopting the shape of the Tassie-
Model, together with the calculated ground Charge Density Distribution CDD for the low mass 2s-1d
shell nuclei using the occupation number of the states where the sub-shell 2s is included with an
occupation number of protons (a ) .
Extended calculations for sputtering yield through bombed Iron – target by ( H,D ,T ,He ) ions plasma are accomplished .The calculations include changing the input parameters : the energy of ( H,D ,T ,He ) ions plasma, the hit target angle of Iron, change atomic mass of incident ion. The program TRIM is used to accomplish these calculations. The results show that sputtering yield is directly dependent on these parameters. It can change the incident angle of ( H,D ,T ,He ) ions and energy&n
... Show More External Morphological study of species Saprinus discoidalis of subfamily saprininae from family Histeridae of the order coleopteran. The specements of the present study were collected from Salahdin Governor-ate (Beigi &Balad) and Governorate during May 2012. The present study included detailed description of most body parts (Head, Thorax, Abdomen and their appendages) identification and recognition of species study male genitalia. The species Saprinus discoidalis LeConte is a new record to Iraqi fauna of Coleoptera.
A total of 680 fish specimens belonging to 31 species from the Yemeni coastal waters of the Red Sea were inspected for the isopod infestations. Four isopod species belonging to three families of the suborder Cymothoida were detected. These are: Aega psora (Linnaeus, 1758) from Lethrinus lentjan, Natatolana insignis Hobbins and Jones, 1993 from Abalistes stellatus, Excorallana tricornis (Hansen, 1890) from Epinephelus fuscoguttatus, E. guttatus and E. tauvina and Alcirona krebsi Hansen, 1890 from Epinephelus microdon. All these isopod species are reported here for the first time from the Yemeni coastal waters of the Red Se
... Show MoreThis study was conducted to determining the variable effects on water quality of Greater Zab River in Erbil province, Iraq, using multivariate statistical analysis. Seventeen variables were monitored in four sampling sites during one year (from May 2012 to April 2013). The dataset were treated using principal component analysis (PCA)/ factor analysis (FA), cluster analysis (CA) to the most important factors affecting water quality, sources of pollution and suitability of water for drinking consumption and irrigation. Six factors were identified as responsible for the data structure explaining 73.5% of the total variance in the dataset and are conditionally named, hydrochemical from weathering, mineral salts and domestic wastes. CA showed
... Show MoreCitrate-gel auto combustion technique was used to synthesize nickel-copper mixed ferrite nanoparticles NixCu1-xFe2O4 (x= 0.0, 0.4, 1.0) with different calcinating temperatures (200, 450, 650 and 850 °C). Structural, morphological, magnetic, and electrical properties were studied using X-ray diffraction (XRD), transmission electron microscopy (TEM), field emission scanning electron microscopy (FE-SEM), Fourier transform infrared spectroscopy (FTIR), vibrating sample magnetometer (VSM), and LCR meter in order to determine significant influences of Cu2+ cations content in nickel ferrite. The XRD patterns showed that all compositions had cubic spinels, except CuFe2O4
... Show MoreThis article conclude a theoretical study for the possibility to produce additional electric power from Iraqi steam power plants by cutting – off high-pressure feed water heaters . Three separated steam power plants which Dura , south –Baghdad and Nasria were studied . The investigation showed the possibity of increasing the electric power from 10 to 15% for Dura and Nasria , whereas 6% for south – Baghdad . According to the nowadays of operation to Iraqi steam power plants , the results showed that by cutting–off high pressure feed water heaters we can generate additional electric power about 250 MW during 3-4 hrs. daily. In addition, the fuel consumption can be reduced in comparison with diesel generat
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In this work, an experimental investigation has been done for heat transfer by natural-convection through a horizontal concentric annulus with porous media effects. The porous structure in gap spacing consists of a glass balls and replaced by plastic (PVC) balls with different sizes. The outer surface of outer tube is isothermally cooled while the outer surface of inner tube is heated with constant heat flux condition. The inner tube is heated with different supplied electrical power levels. Four different radius ratios of annulus are used. The effects of porous media material, particles size and annulus radius ratio on heat dissipation in terms of average Nusselt number have been analyzed. |
The present paper deals with experimental investigation of the performance of air cooled split air conditioner, with evaporative water mist pre cooling to increase the cooling capacity and reduce the consumption power under hot and dry climate. This investigation considers how the performance can be enhanced by using water mist to pre-cool ambient air entering the condensers by adiabatic cooling process which depends on the ambient air wet bulb temperature; as well the condensing temperature and condensing pressure will be decreased accordingly. So the cooling capacity would be increased and consumption power would be decreased, consequently the energy ratio, EER would be improved. The performance of air cooled air conditioner with water
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