Networking of Tracking Radars of Two Different SAM Weapons to Protect the Missile in Intensive Jamming Environment

Many countries including India use the Russian made SAM-3 (Pechora) surface-to-air missile (SAM) weapon systems to protect their strategic and tactical infrastructure. The mathematical computations done in this paper, conclusively proves that SA-125 low-blow tracking radar of Pechora is vulnerable to jamming. A project was undertaken to overcome the jamming vulnerability of Pechora aiming to design and develop an electronic counter counter measure system. This system networked the Pechora tracking radar with a western tracking radar, Flycatcher, developed by HSA Holland. The latter radar works in a MMW band. When jamming (x band) is employed by enemy aircraft the Low blow radar failed to provide target coordinates. But the flycatcher tracking radar which is tracking in Ka band provided the tracking coordinates (after parallax correction) to the command guidance computer. This way the missile guidance is protected until missile warhead in missile blasts near the target. Extensive trials carried out with a number of aircraft sorties proved the success of this developed system against jamming

Aeroload Simulation of Interceptor Missile using Fin Load Simulator

Interceptor missiles are designed to destroy enemy targets in air. Targets can be destroyed either in atmosphere or out of atmosphere. So for Air Defence scenario, a two layer protection system is required with one taking care of exo atmosphere and another endo atmosphere. In this Air Defence scenario, irrespective of target trajectory interceptor should neutralise it. So the control, guidance are to be designed and validated thoroughly with various scenarios of interceptor and target. These interceptors sense the rates from rate gyroscopes and accelerations from accelerometers which are fitted on board the interceptor. The navigation algorithm calculates the interceptor’s position and velocity from these rates and accelerations from time to time. Using these interceptor data and target information received from ground RADAR or on board seeker, guidance calculates accelerations demand and subsequently rate demand. The control algorithm runs in on board mission computer along with guidance. The control algorithm calculates the commanded rate and eventually commanded deflections to the control fins to move towards the target. The fins have to move as per commanded deflections to meet the mission objective of hitting the target. But the load known as aeroload which comes on the control fins during mission, causes control fins not to move as per command. Due to the difference between control command and physical movement of fin, the expected path towards target deviates. This increases the miss distance and also misses the target hit. This aeroload scenario is to be simulated on ground and some feature is to be designed to take care of it during mission. By studying the control system behaviour due to load, the control autopilot is to be automatically tuned to compensate for the loss in commanded deflections. This scenario can be carried out in Hardware-in-Loop simulation (HILS) setup. Mission load conditions can be applied on hardware actuation system in HILS setup and mission performance can be seen and also with different loads and different autopilot tunings

Modeling horizontal gene transfer (HGT) in the gut of the Chagas disease vector Rhodnius prolixus

<p>Abstract</p> <p>Background</p> <p>Paratransgenesis is an approach to reducing arthropod vector competence using genetically modified symbionts. When applied to control of Chagas disease, the symbiont bacterium <it>Rhodococcus rhodnii</it>, resident in the gut lumen of the triatomine vector <it>Rhodnius prolixus </it>(Hemiptera: Reduviidae), is transformed to export cecropin A, an insect immune peptide. Cecropin A is active against <it>Trypanosoma cruzi</it>, the causative agent of Chagas disease. While proof of concept has been achieved in laboratory studies, a rigorous and comprehensive risk assessment is required prior to consideration of field release. An important part of this assessment involves estimating probability of transgene horizontal transfer to environmental organisms (HGT). This article presents a two-part risk assessment methodology: a theoretical model predicting HGT in the gut of <it>R. prolixus </it>from the genetically transformed symbiont <it>R. rhodnii </it>to a closely related non-target bacterium, <it>Gordona rubropertinctus</it>, in the absence of selection pressure, and a series of laboratory trials designed to test the model.</p> <p>Results</p> <p>The model predicted an HGT frequency of less than 1.14 × 10^-16per 100,000 generations at the 99% certainty level. The model was iterated twenty times, with the mean of the ten highest outputs evaluated at the 99% certainty level. Laboratory trials indicated no horizontal gene transfer, supporting the conclusions of the model.</p> <p>Conclusions</p> <p>The model treats HGT as a composite event, the probability of which is determined by the joint probability of three independent events: gene transfer through the modalities of transformation, transduction, and conjugation. Genes are represented in matrices and Monte Carlo method and Markov chain analysis are used to simulate and evaluate environmental conditions. The model is intended as a risk assessment instrument and predicts HGT frequency of less than 1.14 × 10^-16per 100,000 generations. With laboratory studies that support the predictions of this model, it may be possible to argue that HGT is a negligible consideration in risk assessment of genetically modified <it>R. rhodnii </it>released for control of Chagas disease.</p

Parasitic Strip Loaded Dual Band Notch Circular Monopole Antenna with Defected Ground Structure

In this article a parasitic strip loaded monopole antennas are designed to notch dual and triple bands. The designed models are constructed on one side of the substrate material and on the other end defected ground structures are implemented. The basic antenna comprises a tuning stub and a ground plane with tapered shape slot as DGS. Another model is constructed with circular monopole radiating element on front side and similar kind of ground structure used in the basic rectangular tuning stub antenna. To create notched bands with tuning stubs, two symmetrical parasitic slits are placed inside the slot of the ground plane. The basic model is of the rectangular stub notching triple band and the circular tuning stub antenna notching dual band. Dual band notched circular tuning stub antenna is prototyped on FR4 substrate and measured results from vector network analyzer are compared with simulation results of HFSS for validation

On the order of approximation in the random central limit theorem for m-dependent random variables

We consider a random number Nn of m-dependent random variables Xk with a common distribution and the partial sums SNn = &sum;Nn j=1 Xj , where the random variable Nn is independent of the sequence of random variables {Xk; k &ge; 1} for every n &ge; 1. Under certain conditions on the random variables Xk and Nn; we obtain the limit distribution of the sequence SNn and the corresponding rate of convergence after suitable normalization.We consider a random number Nn of m-dependent random variables Xk with a common distribution and the partial sums SNn = &sum;Nn j=1 Xj , where the random variable Nn is independent of the sequence of random variables {Xk; k &ge; 1} for every n &ge; 1. Under certain conditions on the random variables Xk and Nn; we obtain the limit distribution of the sequence SNn and the corresponding rate of convergence after suitable normalization

Structural and optical properties of vanadium doped akaline earth lead zinc phosphate glasses

The structural properties of vanadium doped alkaline earth lead zinc phosphate glasses have been investigated by XRD, UV-Visible, EPR, FT-IR and Raman spectroscopy techniques. XRD analysis has confirmed that the samples are X-ray amorphous. The optical band gap energy (Eopt) is observed to decrease with the replacement of alkaline earth content, whereas reverse trend is observed in Urbach energy (ΔE) and optical basicity (th). The spin-Hamiltonian parameter, dipolar hyperfine coupling and covalency parameters have been obtained from EPR spectra. Depolymerization of the phosphate network by the replacement of alkaline earth content in glasses which are consisting of mainly PO32- and PO43- units, was detected by FT-IR spectra. The structural modification due to breakage of P=O bond and the formationof P-O-P bonds in the different compositions have been studied by Raman spectra. The physical properties have been measured and observed to increase with the replacement of alkaline earth content. The replacement of BaO has improved the strength of the cross-links between the phosphate chains of the glass

Chernoff-type inequality and variance bounds

After a brief review of the work on Chernoff-type inequalities, bounds for the variance of functions g(X, Y) of a bivariate random vector (X, Y) are derived when the marginal distribution of X is normal, gamma, binomial, negative binomial or Poisson assuming that the variance of g(X, Y) is finite. These results follow as a consequence of Chernoff inequality, Stein-identity for the normal distribution and their analogues for other distributions as obtained by Cacoullos, Papathanasiou, Prakasa Rao, Sreehari among others. Some interesting inequalities in real analysis are derived as special cases

On some properties of the geometric distribution

In this note, a necessary and sufficient condition for the n-divisibility of a random variable (r.v.) with support contained in {0, 1, 2,...} is given. Next a characterization of the geometric distribution is obtained. Also bounds for P(X = k+1) are given when the distribution of an infinitely divisible r.v. X is known to coincide with the geometric distribution at the points 0, 1,..., k