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.

Methodology of justification the type and evaluation of quality group search of defects in the repair radio-electronic means

Abstract: Context. Radioelectronic devices are continuously complicated, which complicates the process of restoring their efficiency, when the diagnosis consumes the largest labor costs and time. Therefore, the promising direction of increasing the efficiency of the renewal of modern electronic means is to improve diagnostic support. Objective. The purpose of the article is to increase the efficiency of diagnostic provision of radio electronic means at the expense of a reasonable choice of the type of group search of defects. Method. In the work analytical studies of conditional algorithms of diagnosis with the use of graph theory theory, probability theory and the theory of discrete search – a scientific discipline that studies the diagnostic process when restoring the efficiency of complex technical objects with varying degrees of damage through research and optimization of procedures and algorithms for detection of a priori – in unknown number of elements with given properties on the finite structurally-bounded set according to some criterion. Results. The method of choosing the type of algorithm of group search of defects at given restrictions and assumptions on the criterion of minimum labor costs on the basis of generalization of the graph-analytical model of group search of defects with quantitative estimation of probabilistic, time and cost indicators of the quality of the process of diagnosing radioelectronic devices with different degree of damage, which allows to pre-substantiate the most appropriate algorithm for group defects search for use in the development of diagnostic support for modern radio ectronic means. Conclusions. For the first time, various types of group search of defects with a quantitative estimation of the efficiency of their use depending on the features of radio-electronic means and the conditions for their restoration of efficiency are considered in a complex way.

Modeling and performance analysis of uplink scheduling algorithm in mobile WiMAX systems

Abstract: Extensive numbers of the IEEE 802.16e Mobile WiMAX scheduling proposals focus on simulation for obtaining performance measures of the proposed scheduling algorithm. There is also handful of article that focused on the mathematical modeling. However, the model is derived assuming the traffic from different quality of service (QoS) classes is separated, which allow for independent analysis. In this paper, we propose an uplink (UL) scheduling algorithm that considers the adaptive modulation and coding scheme and QoS parameters of all five service classes. The resources are distributed in two stages. The first stage allocates the resources to different classes of service in accordance to the threshold based priority while the second stage allocates the resources within the same class with the exhaustive service strategy. A mathematical model that combine the different QoS classes of Mobile WiMAX is formulated and it is derived based on the weighted sum of the mean waiting time for the individual queues or known as pseudo-conservation law.

Analysis on mechanical property for varied geometry and structure parameters of silicon based filtration membrane for artificial kidney

Abstract: Silicon and Silicon Nitride are vigorously utilized and explored in micro and nano fabrication technology as they have excellent mechanical and electrical characteristics suitable for NEMS device application. In this study, both of them are analyzed using COMSOL Multiphysics software to evaluate the strength capability of the material when used as filtration membrane in artificial kidney. The artificial filtration membrane is a crucial part in an artificial kidney system as it functions to filter out all wastes from blood stream. This paper investigates the effect of membrane thickness experiencing applied pressure of 1332.3 Pa and 7332.7 Pa on membrane deflection and von Mises stress at the center of the filtration membrane. Those mechanical characteristics at different pore geometry and structure are evaluated against applied pressure on the filtration membrane surface. The results show that the pore geometry and shape for a membrane with thickness of higher than 200 nm will not have significant influences on the deflection and stress characteristics. Therefore, thicker membrane will result to a more stable filtration process that would be able to withstand simulated blood stream pressure in an artificial kidney.