Hierarchical Design Based Intrusion Detection System For Wireless Ad hoc Network

In recent years, wireless ad hoc sensor network becomes popular both in civil and military jobs. However, security is one of the significant challenges for sensor network because of their deployment in open and unprotected environment. As cryptographic mechanism is not enough to protect sensor network from external attacks, intrusion detection system needs to be introduced. Though intrusion prevention mechanism is one of the major and efficient methods against attacks, but there might be some attacks for which prevention method is not known. Besides preventing the system from some known attacks, intrusion detection system gather necessary information related to attack technique and help in the development of intrusion prevention system. In addition to reviewing the present attacks available in wireless sensor network this paper examines the current efforts to intrusion detection system against wireless sensor network. In this paper we propose a hierarchical architectural design based intrusion detection system that fits the current demands and restrictions of wireless ad hoc sensor network. In this proposed intrusion detection system architecture we followed clustering mechanism to build a four level hierarchical network which enhances network scalability to large geographical area and use both anomaly and misuse detection techniques for intrusion detection. We introduce policy based detection mechanism as well as intrusion response together with GSM cell concept for intrusion detection architecture.Comment: 16 pages, International Journal of Network Security & Its Applications (IJNSA), Vol.2, No.3, July 2010. arXiv admin note: text overlap with arXiv:1111.1933 by other author

Cylindrically symmetric wormholes

This paper discusses traversable wormholes that differ slightly but significantly from those of the Morris-Thorne type under the assumption of cylindrical symmetry. The throat is a piecewise smooth cylindrical surface resulting in a shape function that is not differentiable at some value. It is proposed that the regular derivative be replaced by a one-sided derivative at this value. The resulting wormhole geometry satisfies the weak energy condition.Comment: Supplied missing figures; 15 pages AMSTe

Possible existence of wormholes in the galactic halo region

Two observational results, the density profile from simulations performed in the $\Lambda$CDM scenario and the observed flat galactic rotation curves, are taken as input with the aim of showing that the galactic halo possesses some of the characteristics needed to support traversable wormholes. This result should be sufficient to provide an incentive for scientists to seek observational evidence for wormholes in the galactic halo region.Comment: 11 pages, 3 figures, 1 table, Eur. Phys. J. C (2014) 74:2750, DOI 10.1140/epjc/s10052-014-2750-

The formation of molecular hydrogen in the interstellar medium

H2 is the most abundant molecule in the interstellar medium and forms on the surface of interstellar dust grains. Laboratory studies have been conducted of HD formation on a dust grain analogue, which is a highly-oriented pyrolytic graphite surface held at 15 K, under ultra-high vacuum. The molecules desorb from the surface in a distribution of ro-vibrational states, which are probed using Resonance Enhanced Multi-Photon Ionization Spectroscopy. HD in a particular ro-vibrational state is ionized using laser photons detected by a time-of-flight mass spectrometer. The HD+ ion yields are then data processed to obtain the relative rotational populations of HD formed within one vibrational level and an average rotational temperature can be found. In this thesis, HD formed in vibrational states v = 3 – 7 have been studied. This carries on from previous studies of HD and H2 in the v = 1 and 2 states. Within each vibrational level, the most populated rotational state was found to be J = 1 or 2. The most populated vibrational state was found to be v = 4. The HD experimental results were extrapolated to give the relative ro-vibrational population distribution of nascent H2, which provides a new model for the formation pumping of H2. This new formation pumping model has been implemented into a radiative transfer code, written by Casu and Cecchi-Pestellini, which takes into account formation, radiative and collisional pumping mechanisms to calculate the total population distribution of H2 in an interstellar cloud and to generate H2 spectra. The sensitivity of the H2 spectra to the physical conditions of interstellar dark clouds, such as cloud density and temperature, has been investigated. H2 spectra generated using the new experimentally-derived formation pumping model has also been compared to H2 spectra generated using other established, theoretically-derived formation pumping models