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The HTTP flooding attack is the hardest type of DDoS attacks to detect since the malicious packets are hidden in the huge amount of normal traffic. Most detection schemes available up to now use similarity method of communication attributes (i.e. fixed threshold for every attribute ) or machine learning algorithms.it is notable,however,that attributes number very dramatically according to the users activity. Also, using machine learning need a large amount of data for training.In this paper, we introduce a new detection scheme for HTTP flooding attack that exhausting servers. the proposed detection scheme is based on HTTP request/raspons protocol.During normal cases, any server can measure various statistical attributes for its users and their traffic. a server can keep the statistical attributes as a reference profile. during the attack time, measuring some attributes for every connection (i.e. Request number, Response number, Not finished connections number, Number of TCP packets, Number of UDP packets and Number of ICMP packets) then computes distance between its attributes and statistical attributes in normal cases. the proposed detection scheme uses small amount of data to specify the score for a normal connection, also it does not take into consideration a fixed threshold for every attribute in normal connections. Extensive trace-driven simulation has been conducted to demonstrate the efficiency of the proposed scheme in terms of its detection rate, probability of false positive and also average detection time.

The HTTP flooding attack is the hardest type of DDoS attacks to detect since the malicious packets are hidden in the huge amount of normal traffic. Most detection schemes available up to now use similarity method of communication attributes (i.e. fixed threshold for every attribute ) or machine learning algorithms.it is notable,however,that attributes number very dramatically according to the users activity. Also, using machine learning need a large amount of data for training.In this paper, we introduce a new detection scheme for HTTP flooding attack that exhausting servers. the proposed detection scheme is based on HTTP request/raspons protocol.During normal cases, any server can measure various statistical attributes for its users and their traffic. a server can keep the statistical attributes as a reference profile. during the attack time, measuring some attributes for every connection (i.e. Request number, Response number, Not finished connections number, Number of TCP packets, Number of UDP packets and Number of ICMP packets) then computes distance between its attributes and statistical attributes in normal cases. the proposed detection scheme uses small amount of data to specify the score for a normal connection, also it does not take into consideration a fixed threshold for every attribute in normal connections. Extensive trace-driven simulation has been conducted to demonstrate the efficiency of the proposed scheme in terms of its detection rate, probability of false positive and also average detection time.

A novel rhodamine-pyrazole based molecular probe was designed and easily synthesized. The probe could to detect several analytes in aqueous solution at biological pH (HEPES, pH = 7.2). Several heavy metal cations, including Cu2+, Fe3+, Al3+, Hg2+ and Ni2+ were detected discriminately by the probe. Also, the novel compound exhibited a good sensory selectivity towards S2O52− by both absorption and emission spectra. Moreover, probe/Cu2+ complex could to detect several anions, including F−, CN−, S2−, CH3COO−, CO32– and NO2−. Furthermore, the probe exhibited a high potential to work as a molecular system able to perform a number of logical operations such as AND, NAND, NOR and INHIBIT logic gates.

The normal and superconducting properties of Bi1.7Pb0.30Sr2Ca2−xLaxCu2Oy (Bi, Pb):2223 system with various x values (0.00 ≤ x ≤ 0.30) have been reported. It is found that the replacement of Ca2+ by La3+ up to 0.30 does not influence the phase purity of the pure system, while the orthorhombic distortion, excess oxygen, effective Cu valance and hole carriers/Cu ions are clearly affected. Further, the doping distance and crystal geometry factor are decreased, but the distance between neighboring Cu-atoms and density of excess doping are increased. Furthermore, the DTA diagrams show strong endothermic peaks Tm at 844.1, 848, 850.1 and 857.4 °C for pure and La samples, respectively. The mass loss determined by TGA displayed a sharp mass loss started at about 800 °C and extended to 1000 °C for all samples. Although the critical temperatures Tc of the samples are decreased by La insertion …

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