Non‐dominated sorting particle swarm optimization (NSPSO) and network security policy enforcement for Policy Space Analysis

Network operators depend on security services with the aim of safeguarding their IT infrastructure. Various types of network security policies are employed on a global scale and are disseminated among several security middleboxes implemented in networks. But, owing to the complications in security policies, it is not quite efficient to directly use the path‐wise enforcement schemes that are prevalent. The major motivation of this work is to improve security levels and solve the policy enforcement problem. For the first time, this work reports the issue of policy enforcement on middleboxes. The major contribution of this work is to design security policy enforcement as a Weighted K Set Covering Problem, and we designed a Policy Space Analysis (PSA) tool intended for a group of operations in the security policy. This PSA tool was developed based on range‐signified hyper‐rectangles, which are indexed by the Hilbert R‐tree. Leveraging the PSA, we first investigated the topological features of various kinds of policies. Balancing the PSA tool in a non‐dominated sorting particle swarm optimization technique exposes the intrinsic difficulties of this security strategy and provides guidance for designing the enforcement approach. In addition, in this research, a new fuzzy rule‐based classification system is introduced for packet classification. A scope‐wise policy enforcement algorithm was proposed, which chooses a moderate number of enforcement network nodes for deploying multiple policy subsets in a greedy manner. This scheme is much quicker compared with the first one and therefore has found its application in real‐time deployments.     

Synthesis of nanocrystalline hydroxyapatite using surfactant template systems: Role of templates in controlling morphology

Hydroxyapatite (HA) nanopowder was synthesized by reverse microemulsion technique using calcium nitrate and phosphoric acid as starting materials in aqueous phase. Cyclohexane, hexane, and isooctane were used as organic solvents, and Dioctyl sulfosuccinate sodium salt (AOT), dodecyl phosphate (DP), NP5 (poly(oxyethylene)₅ nonylphenol ether), and NP12 (poly(oxyethylene)₁₂ nonylphenol ether) as surfactants to make the emulsion. Effect of synthesis parameters, such as type of surfactant, aqueous to organic ratio (A/O), pH and temperature on powder characteristics were studied. It was found that the surfactant templates played a significant role in regulating the morphology of the nanoparticle. Hydroxyapatite nanoparticle of different morphologies such as spherical, needle shape or rod-like were obtained by adjusting the conditions of the emulsion system. Synthesized powder was characterized using X-ray diffraction (XRD), BET surface area and transmission electron microscopy (TEM). Phase pure HA nanopowder with highest surface area of 121 m²/g were prepared by this technique using NP5 as a surfactant. Densification studies showed that this nanoparticle can give about 98% of their theoretical density. In vitro bioactivity of the dense HA compacts was confirmed by excellent apatite layer formation after 21 days in SBF solution. Cell material interaction study showed good cell attachment and after 5 days cells were proliferated on HA compacts in OPC1 cell culture medium. The results imply this to be a versatile approach for making hydroxyapatite nanocrystals with controlled morphology and excellent biocompatibility.     

A framework for evaluating ERP projects

The objective of this paper is to propose a methodological framework for dealing with the complex problem of evaluating Enterprise Resource Planning (ERP) projects. The competitive pressure unleashed by the process of globalization is driving implementation of ERP projects in increasingly large numbers. They occupy a dominant space in today's rapidly increasing IT investments. Paradoxically, researchers have noted a deteriorating trend of evaluation of these investments. Considering huge organizational stakes coupled with a high risk of failure associated with the ERP projects, it is imperative that they are properly evaluated. Conventional methodology, which reckoned cost displacement as the only benefit, has proved inadequate for modern IT projects that have decreasing scope for cost displacement and an increasing focus on effectiveness objectives. Effectiveness is a multi-dimensional attribute and is not amenable to easy quantification. ERP projects need multi-dimensional evaluation criteria and a methodology that extends into the implementation phase as their profile really shapes up in the latter. A solution, in the form of a process framework that incorporates participatory learning and decision-making processes based on Nominal Group Technique (NGT) and the evaluation methodology adopting the Analytical Hierarchy Process (AHP), is proposed. A case example is given to illustrate its applicability in practice.     

Experimental investigation and multiresponse genetic optimization of drilling parameters for self-healing GFRP

Journal of Mechanical Science and Technology - Self-healing materials heal partially or completely when damage occurs to restore the functionality of the material. Self-healing technology has found...     

Evaluation of concentration dependant diffusion coefficients of carbon in a dissimilar joint of ferritic steels

When dissimilar weldments between 9Cr-1Mo and 2¼Cr-1Mo ferritic steels are exposed to high temperature, microstructural and microchemical modifications are observed near the weld interface. Diffusion of carbon driven by the activity gradient from low Cr to high Cr steel leads to the formation of carbon enriched ‘hard’ zone and carbon depleted ‘soft’ zone near the fusion joint. The present paper deals with the measurement of carbon diffusion profiles and the evaluation of concentration dependent diffusion coefficients of carbon across the interface at a temperature of 1023 K. Accurate carbon concentration profiles are generated using carbon calibration graph. The profiles are smoothened to reduce the experimental scatter and the concentration dependant diffusion coefficients are determined using Den Broeder’s method. In the base materials, where the concentration gradient is extremely small, D(c) values are determined using Hall’s method. Variation in D(c) across the weld interface is understood based on the microstructural and microchemical changes that take place during heat treatment.     

Probability Collectives: A multi-agent approach for solving combinatorial optimization problems

Complex systems generally have many components. It is not possible to understand such complex systems only by knowing the individual components and their behavior. This is because any move by a component affects the further decisions/moves by other components and so on. In a complex system, as the number of components grows, complexity also grows exponentially, making the entire system to be seen as a collection of subsystems or a Multi-Agent System (MAS). The major challenge is to make these agents work in a coordinated way, optimizing their local utilities and contributing the maximum towards optimization of the global objective. This paper discusses the theory of Collective Intelligence (COIN) using the modified version of Probability Collectives (PC) to achieve the global goal. The paper successfully demonstrated this approach by optimizing the Rosenbrock function in which the coupled variables are seen as autonomous agents working collectively to achieve the function optimum. To demonstrate the PC approach on combinatorial optimization problems, two test cases of the Multi-Depot Multiple Traveling Salesmen Problem (MDMTSP) with 3 depots, 3 vehicles and 15 nodes are solved. In these cases, the vehicles are considered as autonomous agents collectively searching the minimum cost path. PC is successfully accompanied with insertion, elimination and swapping heuristic techniques. The optimum results to the Rosenbrock function and both the MDMTSP test cases are obtained at reasonable computational costs.     

Effect of Postweld Heat Treatment on Microstructure, Hardness, and Tensile Properties of Laser-Welded Ti-6Al-4V

The effects of postweld heat treatment (PWHT) on 3.2-mm- and 5.1-mm-thick Ti-6Al-4V butt joints welded using a continuous wave (CW) 4-kW Nd:YAG laser welding machine were investigated in terms of microstructural transformations, welding defects, and hardness, as well as global and local tensile properties. Two postweld heat treatments, i.e., stress-relief annealing (SRA) and solution heat treatment followed by aging (STA), were performed and the weld qualities were compared with the as-welded condition. A digital image correlation technique was used to determine the global tensile behavior for the transverse welding samples. The local tensile properties including yield strength and maximum strain were determined, for the first time, for the laser-welded Ti-6Al-4V. The mechanical properties, including hardness and the global and local tensile properties, were correlated to the microstructure and defects in the as-welded, SRA, and STA conditions.     

Vapor Phase Beckmann Rearrangement of Cyclohexanone Oxime over Different Ferrierite Zeolite Catalysts

Ferrierite zeolite catalysts prepared using different procedures have been tested for their activity for vapor phase Beckmann rearrangement of cyclohexanone oxime to -caprolactam. We report here the results of a study seeking the influence of temperature, nitrogen feed rate, oxime concentration and solvents on the catalyst performance. At low concentration of oxime (2.5 wt%), using acetonitrile as solvent the maximum in the conversion of oxime and selectivity to -caprolactam has been obtained. The presence of weak, medium and strong acid sites as indicated by temperature-programmed desorption of NH₃ corroborates well with the catalytic activities of various ferrierites shown here. Solvent polarity is found to significantly affect the conversion of cyclohexanone oxime.     

Determination of bacterial activity by use of an evanescent-wave fiber-optic sensor

A novel technique based on fiber-optic evanescent-wave spectroscopy is proposed for the detection of bacterial activity in human saliva. The sensor determines th e specific concentration of Streptococcus mutans in saliva, which is a major causative factor in dental caries. In this design, one prepares the fiber-optic bacterial sensor by replacing a portion of the cladding region of a multimode fiber with a dye-encapsulated xerogel, using the solgel technique. The exponential decay of the evanescent wave at the core-cladding interface of a multimode fiber is utilized for the determination of bacterial activity in saliva. The acidogenic profile of Streptococcus mutans is estimated by use of evanescent-waveabsorption spectra at various levels of bacterial activity.