Increasing coverage to improve detection of network and host anomalies

For intrusion detection, the LERAD algorithm learns a succinct set of comprehensible rules for detecting anomalies, which could be novel attacks. LERAD validates the learned rules on a separate held-out validation set and removes rules that cause false alarms. However, removing rules with possible high coverage can lead to missed detections. We propose three techniques for increasing coverage—Weighting, Replacement and Hybrid. Weighting retains previously pruned rules and associate weights to them. Replacement, on the other hand, substitutes pruned rules with other candidate rules to ensure high coverage. We also present a Hybrid approach that selects between the two techniques based on training data coverage. Empirical results from seven data sets indicate that, for LERAD, increasing coverage by Weighting, Replacement and Hybrid detects more attacks than Pruning with minimal computational overhead.     

Scheduling UET-UCT tasks: branch-and-bound search in the priority space

The paper is concerned with the problem of scheduling partially ordered unit execution time tasks on parallel processors with unit communication delays and release times. Two criteria are considered, the maximum lateness and its particular case, the makespan. This problem plays an important role in scheduling theory and was originally inspired by the applications to multi-processor computer systems. It is well known that for both criteria the problem is NP-hard in the strong sense. The paper presents an implementation of the branch-and-bound method which does not partition the feasible region explicitly. The theoretical results are complemented by computational experiments.     

Functionalized polystyrene latex particles as substrates for ATRP: Surface and colloidal characterization

In this work, the process for producing polystyrene particles surface functionalized with a thin shell of ATRP initiator polymerized alone or along with styrene and a crosslinker, is presented. Copolymerization of styrene and acrylic end-capped ATRP initiator to generate a thin shell on the fully polymerized core particles suffered from secondary nucleation owing to their possible incompatibility with the core particles and their own colloidal stability. One step functionalization processes, where the shell forming monomers are added directly to the 70% polymerized core particles, lead to significant changes in the resulting particle morphologies. The shot addition of these monomers led to a very uniform surface morphology without any secondary nucleation owing to quick coalescence of the secondary particles on the soft surface of the seed particles. Addition of crosslinker to the system helped in effectively eliminating the smaller particles generated due to secondary nucleation along with the chemical networking.     

Models for minimum explosible concentration of organic dust clouds handled in industries

Dust explosion hazard exists in plants and facilities wherever combustible dusts are hardled. Minimum explosible concentration of dust clouds is an important factor requiring special attention for hazard evaluation if any technological equipment is to be protected by inertisation. The mathematical models available for prediction of this parameter have been analysed for their application to organic dust clouds. Solution of the most general mode for determination of minimum explosible concentration of dust clouds proposed by Mitsui and Tanaka is presented, together with the comparison with experimental data. It has been found that the model is not successful in predicting the minimum explosible concentration for organic dusts. Recommendations on requirement of development of a new model for prediction of minimum explosible concentration of an organic dust such as polyethylen have been given.     

Post spinning modification of PAN fibres — a review

Post spinning modifications play an important role in improving the mechanical properties, density and structure of PAN fibres. Post spinning modifications affect the thermal and kinetic parameters during stabilization and alter the overall stabilization mechanism. The present paper presents a review of the different types of post spinning modifications previously attempted on PAN fibres and the effects of these modifications on the resulting carbon fibres.     

Integrated Front-End Radar Receivers at Ka-Band

This paper describes the Integrated Finline Front-end Radar Receivers at Ka-Band. The Front-receivers developed for Radar applications include combining of finline components on a single MIC substrate with various planar transmission lines. The integrated systems so developed have better noise figure and control over phase and gain imbalances as compared to discrete component systems. Two types of Integrated Front-ends Radar receivers are described here. The developed systems are highly compact and reliable.     

Homogeneous charge compression ignition of binary fuel blends

The present experimental investigation aims to understand the homogeneous combustion chemistry associated with binary blends of three surrogate components for practical fuels, including toluene, isooctane, and diisobutylene-1 (DIB-1). Specifically, high-pressure autoignition characteristics of the three neat fuel components as well as the fuel blends of toluene + isooctane and toluene + DIB-1 are studied herein. Experiments are conducted in a rapid compression machine at compressed pressures varying from 15 to 45 bar and under low to intermediate temperatures. To obtain insights into interactions among fuels, the relative proportion of the two neat fuels in the reactive mixtures is systematically varied, while the total fuel mole fraction and equivalence ratio are kept constant. Experimental results demonstrate that ignition delays for neat toluene are more than an order of magnitude longer than those for neat isooctane. Whereas DIB-1 has ignition delays shorter than those for isooctane at higher temperatures, at temperatures lower than 820 K DIB-1 shows a longer ignition delay. Although the ignition delays of binary blends lie in between the two extremes of neat components, the variation of ignition delay with the relative fuel proportion is seen to be highly nonlinear. Especially, a small addition of isooctane or DIB-1 to toluene can result in greatly enhanced reactivity. In addition, the effect of DIB-1 addition to toluene is more significant than the effect of isooctane addition. Furthermore, in the compressed temperature range from 820 to 880 K, ignition delay of the toluene + isooctane blend shows greater sensitivity to temperature than that of isooctane.     

Prototyping bio-nanorobots using molecular dynamics simulation and virtual reality

This paper presents a molecular mechanics study using a molecular dynamics software (NAMD) coupled to virtual reality (VR) techniques for intuitive bio-nanorobotic prototyping. Using simulated bio-nano environments in VR, the operator can design and characterize through physical simulation and 3D visualization the behavior of protein-based components and structures. The main novelty of the proposed simulations is based on the characterization of stiffness performances of passive joints-based proteins (α-helix deca-alanine, repressor of primer protein and immunoglobulin protein) and active joints-based viral protein motor (VPL) in their native environment. Their use as elementary bio-nanorobotic components are also simulated and the results discussed.     

Prediction of food thermal process evaluation parameters using neural networks

Two neural networks (ANN) were developed to predict thermal process evaluation parameters g and f(h)/U (the ratio of heating rate index to the sterilizing value), respectively. The temperature change required for the thermal destruction curve to traverse one log cycle (z), cooling lag factor (j(c)) andf(h)/U were input variables for predicting g and z, while j(c) and g were inputs for predicting f(h)/U. The data used to train and verify the ANN were obtained from reported values. Shrinking of input and output variables using natural logarithm function improved the prediction accuracy. The use of "Wardnets" with three slabs of 14 nodes in each slab, with a learning rate of 0.7 and momentum of 0.9 provided the best predictions. The g (unshrunk values) was predicted with a mean relative error of 1.25 +/- 1.77%, and a mean absolute error of 0.11 +/- 0.16 degrees F. The f(h)/U was predicted with a mean relative error of 1.41 +/- 3.40%, and a mean absolute error of 2.43 +/- 15.97, using 10 nodes in each slab. The process time calculated using the g from the ANN models closely followed the time calculated from the tabulated gvalues (RMS=0.612 min, average absolute error=0.466 min with an S.D. of 0.400 min).