National Defence University, Pakistan

About: National Defence University, Pakistan is a education organization based out in Islamabad, Pakistan. It is known for research contribution in the topics: Decision support system & Population. The organization has 802 authors who have published 816 publications receiving 3701 citations. The organization is also known as: National Defence University of Pakistan & National Defence University Islamabad.

Modelling and validation of the vehicle longitudinal model

Abstract: This paper presents the detailed derivation and validation of a full vehicle model to study the behaviour of vehicle dynamics in the longitudinal direction. The model consists of handling and tyre subsystems, an engine model subsystem, an automatic transmission subsystem and a brake model subsystem. The full vehicle model was then validated using an instrumented experimental vehicle based on the driver input from brake and throttle pedals. Vehicle transient handling dynamic tests known as sudden braking tests were performed for the purpose of validation. Several behaviours of the vehicle dynamics were observed during braking and throttling manoeuvres, such as body longitudinal velocity, wheel linear velocity and tyre longitudinal slip, at each quarter of the vehicle. Comparisons of the experimental results and model responses with sudden braking and throttling imposed motions were made in this study. It is concluded that the trends between simulation results and experimental data were found to be almost similar with an acceptable level of error for the application at hand.

Search for lepton-flavor violating decays of the Higgs boson in the μτ and eτ final states in proton-proton collisions at s =13 TeV

Abstract: A search is presented for lepton-flavor violating decays of the Higgs boson to μ τ and e τ . The dataset corresponds to an integrated luminosity of 137 fb - 1 collected at the LHC in proton-proton collisions at a center-of-mass energy of 13 TeV. No significant excess has been found, and the results are interpreted in terms of upper limits on lepton-flavor violating branching fractions of the Higgs boson. The observed (expected) upper limits on the branching fractions are, respectively, B ( H → μ τ ) 0.15 ( 0.15 ) % and B ( H → e τ ) 0.22 ( 0.16 ) % at 95% confidence level.

Increased importance of VHF radars in ground-based air defense

Abstract: We will show how the emergence of new threats is going to affect the operational and technical requirements for Air Defense Systems. We will demonstrate that current ADSs which are augmented by modern VHF radars can be connected together on signal fusion principles, and that such structures are achieving improved effectiveness of airspace control in times of crises or war.

Three-Dimensional Magnetohydrodynamic Mixed Convection Flow of Nanofluids over a Nonlinearly Permeable Stretching/Shrinking Sheet with Velocity and Thermal Slip

Abstract: In this paper, the steady three-dimensional magnetohydrodynamic (MHD) mixed convection flow of nanofluids over a permeable vertical stretching/shrinking sheet with slip conditions is investigated in a numerical manner. As such, two types of nanofluids, Cu-water and Ag-water, had been considered. A similarity transformation was employed to reduce the governing equations to ordinary differential equations, which were then solved numerically using the MATLAB (Matlab R2015a, MathWorks, Natick, MA, USA, 1984) programme bvp4c. The numerical solutions derived from the ordinary differential equations subjected to the associated boundary conditions, were obtained to represent the values of the mixed convection parameter. Dual (upper and lower branch) solutions were discovered in the opposing flow region of the mixed convection parameter. A stability analysis was carried out to prove that the upper branch solution was indeed stable, while the lower branch solution was unstable. The significant effects of the governing parameters on the reduced skin friction coefficients, the reduced local Nusselt number, as well as the velocity and temperature profiles, were presented graphically and discussed in detail.

A Mechanism for Recognizing and Suppressing the Emergent Behavior of UAV Swarm

Abstract: Similar to social animals in nature, UAV swarm is also a complex system that can produce emergent behavior. The emergent behavior of UAV swarm in specific airspace is undoubtedly the act that the defense side does not expect to see; therefore, recognition and suppression of the emergent behavior of UAVs swarm are needed. Based on the analysis of the UAV swarm emergent behavior mechanism, by adopting -divergence method, UAV swarm emergent behavior was quantified, and a rapid recognition mechanism of emergent behavior has been established, thus, making preparation for the suppression of the emergent behavior. In the academic circle, for the first time, in accordance with heuristic rules governing the algorithms of UAV swarm suppression, principle of emergent behavior suppression has been proposed, failure judgment model of UAV swarm control under interference conditions has been constructed, the stability of UAV swarm has been analyzed, and the combat command process of UAV swarm based on OODA loop has been put forward. Through the simulation, the comparison of information entropy and -divergence based emergence measurement method has been made, and -divergence based method has some advantages for measuring the emergence of UAV swarm. From the analysis and discussion of the inhibitory effect on swarm flocking behavior under different interference intensity and timing, conclusion has been drawn that comprehensive suppression on the premise of correct recognition of flocking behavior is the best strategy fighting against UAV swarm emergent behavior.