Analytical Termination of Malicious Nodes (ATOM): An Intrusion Detection System for Detecting Black Hole attack in Mobile Ad Hoc Networks

The decentralized administration and the lack of an appropriate infrastructure causes the MANET prone to attacks. The attackers play on the vulnerable characteristics of the MANET and its underlying routing protocols such as AODV, DSR etc. to bring about a disruption in the data forwarding operation. Hence, the routing protocols need mechanisms to confront and tackle the attacks by the intruders. This research introduces the novel host-based intrusion detection system (HIDS) known as analytical termination of malicious nodes (ATOM) that systematically detects one of the most significant black hole attacks that affects the performance of AODV routing protocol. ATOM IDS performs detection by computing the RREP count (Route Reply) and the packet drop value for each individual node. This system has been simulated over the AODV routing protocol merged with the black hole nodes and the resultant simulation scenario in NS2 has been generated. The trace obtained shows a colossal increase in the packet delivery ratio (PDR) and throughput. The results prove the efficacy of the proposed system.

     

An optimization study for preventing silica gelation and improving filtration effectiveness during pH reduction of high concentration silica solutions

The steam generation processes at the steam-assisted gravity drainage facilities result in huge quantities of wastewater streams, which are characterized by high pH and high silica levels. These concentrated streams need to be neutralized before their disposal via down-hole injection. The neutralization of these high-pH brines results in the formation of a gel-like substance, which makes it difficult to filter the amorphous silica gel. The wastewater used in this study was synthetically prepared using sodium metasilicate to mimic high-concentration silica solutions. Our experiments did not show any advantage of a two-step pH-neutralization process over the single-step process for suppressing silica gelation. A systematic experimental campaign was undertaken to investigate the effects of SiO₂ concentration, NaCl:SiO₂ ratio, and pH on the residual silica concentration, percent silica removal, filtration rate, and filtration effectiveness. For NaCl:SiO₂ ratios higher than 4.5, silica precipitation during pH reduction did not lead to the formation of gel or sol. The response surface methodology (RSM), based on the Doehlert design of experiments, was implemented to optimize the responses and provide high efficacy with fewer experiments. The results from the analysis of variance (ANOVA) analyses of the experimental data were used to evaluate the significance of each term in the quadratic model. 3D response surfaces and 2D contour plots were generated for determining the optimal ranges of independent factors for achieving the maximum silica removal, the highest filtration rate, the best filtration effectiveness, and the minimum residual silica concentration. An optimum operating region was established from the RSM analysis and overlay plot.