An Efficient Security Mechanisms for Different Sort of Attacks in CWSN

One of the major important aspects of wireless sensor networks WSNs is their capability to collect and process huge amounts of information in parallel with the help of small power limited devices enabling their use in observation target detection and various other monitoring applications Recently new ideas have been proposed to develop cognitive WSNs CWSNs to enhance awareness about the network and environment and make adaptive decisions based on the application goals A CWSN is a special network which has many constraints compared to traditional wireless network But the major problem is security In this paper discovering various security threats in these networks and various defense mechanisms to counter these vulnerabilities Various types of attacks on CWSNs are categorized under different classes based on their natures and targets and corresponding to each attack class appropriate security mechanisms are discusse

A unified data flow model for fault tolerant computers

The Dataflow Simulation System (DFSS) at USL was used as the medium on which a functional simulaton of sIFT was produced. DFSS is written in PL/I and is supported by MULTICS. Within the simulation, all the interprocessor communication, fault simulation, system state data, and monitoring were implemented in dataflow and supported directly by DFSS. The actual processor level computation was carried out by the SIFT code in PASCAL. The interface between DFSS in PL/I and the SIFT code in PASCAL was supported under a mechanism in DFSS called a Node Realization Module (NRM)

Sources of origin and meteorological importance of hygroscopic and iceforming nuclei

The hygroscopic nuclei whose source region during the monsoon is the sea penetrate far into the interior and play important role in development of precipitation well inland. The fraction of such nuclei present in the total aerosol constitutes a more dependable criterion for distinguishing maritime airmasses from those of others. Development of rain frequently by all-water and ice-crystal mechanisms have been suggested by the large concentrations noticed of the hygroscopic and ice-forming aerosols respectively. While it is seen that there is a major identifiable singular source, which is the sea, for hygroscopic aerosols at Delhi, it does not appear to be so in the case of ice-forming nuclei. The latter are of varied origin and might be maritime, continental, stratospheric etc

Secondary periodicities of microbursts of TeV gamma rays from the Crab pulsar

Observations were made during the past several years on the Crab pulsar using the Ooty atmospheric Cerenkov array with the aim of detecting possible emission of ultra high energy gamma rays by the pulsar. During the course of these observations, it was found that the Crab pulsar emits TeV gamma rays in bursts of short duration. The microbursts of TeV gamma rays from the Crab pulsar, which were seen in the data of at least three years, also reveal interesting secondary periodicities. It was noticed at first that some bursts could be connected with the others that occurred during the same night or during the next two nights with integral number of cycles of periods 43 + or - 1 minute. Ten possible periods in the vicinity of 43 minutes were determined for all the combinations of bursts for each year. The best values of periods thus obtained were different from year to year. But when, instead of the real time, the number of Crab cycles elapsed between the bursts was used as the unit of time, two values of burst periods - 77460 and 77770 Crab cycles - were found to be significant in the data of at least two years. A Monte Carlo simulation using 1500 trial periods chosen randomly within + or - 5 minutes of the original burst period did not reveal any value of the period as significant

Observations on TeV gamma rays from Geminga and PSR 0950+08

The Geminga (2 CG 195+04) which exhibits a periodicity with a period of 59 to 60 s in its emission of X-rays, GeV gamma rays and TeV gamma rays was studied. During the winter of 1984 to 1985, this object was observed to see if it emits TeV gamma rays with a periodicity approx 60 s. The observations were carried out at two different sites separated by 11 Km with the Ooty Atmospheric Cerenkov Array split into two parts. Data were collected during clear moonless nights for a total duration of 15.3 hours spread over 2 months. Since the first time derivative of period is believed to be large and uncertain. The total data are subdivided into segments of duration not more than 3 days each to steer clear of the effects of P in the phase analysis. If TeV gamma ray signals are seen in each of these segments, it is possible to derive P from observed data

PREPARATION AND EVALUATION OF ORALLY DISINTEGRATING TABLETS OF DROTAVERINE HYDROCHLORIDE USING SUBLIMATION TECHNIQUE

Objective: To formulate orally disintegrating taste masked tablets of drotaverine hydrochloride (HCl) by sublimation technique.Methods: Initially superdisintegrant was selected and its concentration was optimized by pre-compression and post-compression parametric evaluation. Camphor and menthol were used as sublimating agents alone and in combination to mask the taste of drotaverine hydrochloride. Prepared tablets were evaluated for physicochemical evaluation, in vitro dissolution studies and fourier transformation-infrared spectroscopy, differential scanning calorimetry and X-ray diffractometry studies.Results: The optimised formulation DCM2 prepared with a mixture of camphor and menthol was characterised by fourier transformation-infrared spectroscopy, differential scanning calorimetry and X-ray diffractometry studies and found no incompatibility and no major shifts were noticed.Conclusion: The results demonstrated that the prepared drotaverine HCl orally disintegrating tablets showed better taste masking. The present sublimation technique can be effectively used for taste masking and also for orally disintegrating tablets

The Infrared to Gamma-Ray Pulse Shape of the Crab Nebula Pulsar

We analyze the pulse shape of the Crab Nebula pulsar in the near-infrared, optical, ultraviolet, X-ray, and gamma-ray bands, including previously unpublished ROSAT HRI observations. We show that, in addition to the previously known trend for the fluences of the Bridge and Peak 2 to increase with energy relative to the fluence of Peak 1, there is a small but statistically significant trend for both to decrease with energy relative to Peak 1 over the near-infrared range. We find that the phase separation between the two peaks of the pulse profile decreases nearly continuously as a function of energy over 7 decades of energy. We show that the peaks' full-width half-maxima are significantly variable over this energy range, but without any clear pattern to the variability. We find that the differences between the energy dependences of the leading and trailing edge half-width half-maxima of both peaks found by Eikenberry et al. (1996a) also continue over 7 decades of energy. We show that the cusped shape of Peak 2 reverses direction between the infrared/optical and X-ray/gamma-ray bands, while the cusped shape of Peak 1 shows weak evidence of reversing direction between the X-ray and gamma-ray bands. Finally, we find that many of the pulse shape parameters show maxima or minima at energies of 0.5-1 eV, implying that an important change in the pulsar emission is occuring near this energy. Many of these complex phenomena are not predicted by current pulsar emission models, and offer new challenges for the development of such models.Comment: 32 pages; 9 figure

Pulsed emission of TeV gamma rays from Vela pulsar

The Ooty atmospheric Cerenkov array, consisting of 10 parabolic mirrors of 0.9 m diameter and 8 of 1.5 m diameter, was used for observations on the Vela pulsar to see if it emits gamma rays in the TeV energy range. During the winter of 1984-85, the array was split into two parts: (1) consisting wholly of the smaller mirrors, and (2) wholly of the bigger mirrors. The two arrays were operated at two different sites to distinguish a marginally significant genuine pulsar signal from spurious signals produced trivially by chance fluctuations in the background rates. All the mirrors were pointed at the celestial object to track it for durations of the order of 1 to 6 hours during clear moonless nights. The event time data is analyzed to detect a possible pulsed emission of TeV gamma rays using the contemporaneous pulsar elements on the basis of their radio observations on the Vela pulsar. Results from the analyses of observations made during the winters of 1982-83 and 1984-85 on steady pulsed emission and on possible transient emission is presented

Cloud seeding experiment using common salt

An experiment on artificial stimulation of rain using a warm cloud seeding technique was undertaken in three nearby climatologically similar regions, Delhi, Agra and Jaipur in northwest India. Analysis of the data from 18 experiment-seasons has suggested a positive trend of the result, which is found significant by statistical tests

Microburst of TeV gamma rays from the Crab pulsar

Data on Crab pulsar from atmospheric Cerenkov array at Ooty have shown emission of TeV gamma rays in the form of microbursts. These are a series of events which are unusually closely spaced in time with time separations of less than 1.5 milliseconds. The phasogram of events in the bursts when analyzed with the Crab pulsar period shows significant peaks. Data further show that the signal is at the same absolute phase as the radio peak. Monte Carlo calculations show that the probability of peaks being due to chance is very small