Ali Khan N.,Muhammad Ali Jinnah University |
Ahmad Taj I.,Muhammad Ali Jinnah University |
Noman Jaffri M.,Federal Urdu University
Signal Processing | Year: 2011
An efficient method based on 2D signal processing techniques and fractional Fourier transform is presented to suppress interference terms of Wigner distribution (WD). The proposed technique computes Gabor transform (GT) of a multi-component signal to obtain a blurred timefrequency (tf) image. Signal components in GT image are segmented using connected component segmentation and are filtered out using precise application of fractional Fourier transform. A crisp tf representation is then obtained by computing the sum of products of WD and GT of the isolated signal components. The efficacy of the proposed technique is demonstrated using examples of synthetic signals and real-life bat signals. Proposed scheme gives satisfactory performance even when cross-terms of WD overlap auto-terms and computational cost analysis shows that it is more efficient than recent interference suppression techniques of comparable performance. Moreover, the proposed technique does not require any prior info regarding the nature of signal. © 2010 Elsevier B.V. All rights reserved.
Karimov Kh.S.,Academy of Sciences of Tajikistan |
Karimov Kh.S.,Ghulam Ishaq Khan Institute of Engineering Sciences and Technology |
Ahmed M.M.,Muhammad Ali Jinnah University |
Karieva Z.M.,Tajik Technical University |
And 3 more authors.
Sensor Letters | Year: 2011
In this article, the electrical properties of carbon nanotubes (CNTs) films were studied by fabricating Ag/CNT/Ag devices. The nominal thickness of the grown CNTs films was ∼12 μm, and the diameter of multiwalled carbon nanotubes (MWCNTs) varied between 10-30 nm. The current-voltage (I-V) characteristics of the fabricated devices exhibited rectification behaviour (3 at ± 1 V). The effect of humidity on MWCNTs films was investigated by evaluating capacitance and dissipation of the samples at two different frequencies, i.e., 120 Hz and 1 kHz. It is observed that the capacitance and resistance change with changing values of relative humidity (RH) as a function of frequency (f). At f =120 Hz, RH=90%, the observed increases in the capacitance of the sensor was ∼366 times and it was only ∼36 times when measured at f = 1 kHz. Under the same experimental conditions, the observed decrease in the resistance values was ∼656 and ∼627 times respectively. It is assumed that the humidity based electrical response of the cell is associated with doping of the nano-particles by water molecules. To evaluate the dynamics of the water vapour absorption and desorption processes, the average response (2 s/percent) and recovery (8 s/percent) times of the fabricated devices were obtained by capacitance-time measurements. The experimental results have been simulated by defining the device equivalent circuit and capacitance-humidity relationship. Copyright © 2011 American Scientific Publishers All rights reserved.
Hussain T.,Muhammad Ali Jinnah University |
Asghar S.,Muhammad Ali Jinnah University |
Fong S.,Macau University of Science and Technology
Proc. - 6th Intl. Conference on Advanced Information Management and Service, IMS2010, with ICMIA2010 - 2nd International Conference on Data Mining and Intelligent Information Technology Applications | Year: 2010
In Web Usage Mining (WUM), web session clustering plays a key role to classify web visitors on the basis of user click history and similarity measure. Swarm based web session clustering helps in many ways to manage the web resources effectively such as web personalization, schema modification, website modification and web server performance. In this paper, we propose a framework for web session clustering at preprocessing level of web usage mining. The framework will cover the data preprocessing steps to prepare the web log data and convert the categorical web log data into numerical data. A session vector is obtained, so that appropriate similarity and swarm optimization could be applied to cluster the web log data. The hierarchical cluster based approach will enhance the existing web session techniques for more structured information about the user sessions.
Ahmad M.B.,Center for Advanced Studies in Engineering |
Saeed-Ur-Rehman,Center for Advanced Studies in Engineering |
Akram A.,University of Engineering & Technology, Taxila |
Asif M.,Muhammad Ali Jinnah University
Proceedings - 12th International Conference on Frontiers of Information Technology, FIT 2014 | Year: 2014
The problem of insider threats is not new to organizations and research community. Organization cannot afford any kinds of attacks on their confidential information and resources either from insiders or out-siders. The damage done by insiders is more severe than that of external attackers due to their knowledge about the system and potential targets. It has been observed by studying previous case studies of insider attacks that insiders usually get involve in some unusual or suspicious activities prior to launching actual attacks. So observing these kinds of activities and taking proper actions in time may help to avoid such kinds of attacks. In this paper a risk assessment methodology has been presented to compute the threat levels of insiders. Appropriate actions may be taken by knowing about the threat level of each user in order to avoid actual attacks. The methodology not only incorporates technical measures but also some psychological indicators to detect insiders. The difference of this methodology from the previous ones is that it provides a practical way of quantization of risks for insider threats. The methodology is simulated in a test network against different scenarios and results showed that it efficiently categorized users according to their threat level. So it provides a base to deploy non uniform security policies among the users thus reducing overall processing overheads. © 2014 IEEE.
Khan C.,Institute of Management Sciences |
Anwar S.,Institute of Management Sciences |
Bashir S.,Muhammad Ali Jinnah University |
Rauf A.,Imam Muhammad ibn Saud Islamic University |
Amin A.,Institute of Management Sciences
Journal of Intelligent and Fuzzy Systems | Year: 2015
Suitable site selection for a specific purpose is a crucial activity, and of the greatest importance to a project manager. Several methods have been proposed by the research community for effective site selection, but all proposed methods incur high costs. This study explores the combination of a rough set theory approach (RSTA) with Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) for suitable site selection for food distribution. This method provides a set of rules to determine different sites, which ultimately can help management develop strategies for suitable site selection. A set of rules for suitable site selection are derived from information related to a practical case, Pakistan Red Crescent Society (PRCS), to demonstrate the prediction ability of RSTA. The results clearly demonstrate that the RSTA model can be a valuable tool for site identification. Rough set theory also assists management in making appropriate decisions based on their objectives while avoiding unnecessary costs. However, while RSTA provides rules to determine the best sites for food distribution, it does not pinpoint the best sites for food distribution. To be more precise and accurate, this work is extended to another multi-criteria decision-making technique solution: the TOPSIS method. By using this method, this study provides the best top priority site for food distribution of PRCS. © 2015 - IOS Press and the authors. All rights reserved.
Ajab M.,Muhammad Ali Jinnah University |
Taj I.A.,Muhammad Ali Jinnah University |
Khan N.A.,Federal Urdu University
Metrology and Measurement Systems | Year: 2012
Gabor Wigner Transform (GWT) is a composition of two time-frequency planes (Gabor Transform (GT) and Wigner Distribution (WD)), and hence GWT takes the advantages of both transforms (high resolution of WD and cross-terms free GT). In multi-component signal analysis where GWT fails to extract auto-components, the marriage of signal processing and image processing techniques proved their potential to extract autocomponents. The proposed algorithm maintained the resolution of auto-components. This work also shows that the Fractional Fourier Transform (FRFT) domain is a powerful tool for signal analysis. Performance analysis of modified fractional GWT reveals that it provides a solution of cross-terms of WD and blurring of GT. © 2012 Polish Academy of Sciences.
Bin Ahmad M.,Center for Advanced Studies in Engineering |
Akram A.,University of Engineering and Technology |
Asif M.,Muhammad Ali Jinnah University |
Ur-Rehman S.,Center for Advanced Studies in Engineering
Mathematical Problems in Engineering | Year: 2014
Insider threats detection problem has always been one of the most difficult challenges for organizations and research community. Effective behavioral categorization of users plays a vital role for the success of any detection mechanisms. It also helps to reduce false alarms in case of insider threats. In order to achieve this, a fuzzy classifier has been implemented along with genetic algorithm (GA) to enhance the efficiency of a fuzzy classifier. It also enhances the functionality of all other modules to achieve better results in terms of false alarms. A scenario driven approach along with mathematical evaluation verifies the effectiveness of the modified framework. It has been tested for the enterprises having critical nature of business. Other organizations can adopt it in accordance with their specific nature of business, need, and operational processes. The results prove that accurate classification and detection of users were achieved by adopting the modified framework which in turn minimizes false alarms. © 2014 Maaz Bin Ahmad et al.
Hussain T.,Muhammad Ali Jinnah University |
Asghar S.,Muhammad Ali Jinnah University |
Masood N.,Muhammad Ali Jinnah University
Proceedings - 2010 6th International Conference on Emerging Technologies, ICET 2010 | Year: 2010
Web based applications are increasing at an enormous speed and consequently its users are also increasing at an exponential speed. The evolutionary changes in technology have made it possible to capture the users' essence and interactions with web applications through web server log file as web usage. The web usage Mining (WUM) is the process of discovering hidden patterns from the web usage. Due to large amount of "irrelevant information" in the web log, the original log file cannot be directly used in the WUM process. Therefore, the preprocessing of web log file becomes imperative. The proper analysis of web log file is beneficial to manage the websites effectively for administrative and users' prospective. Web log preprocessing is an initial necessary step to improve the quality and efficiency of the later steps of WUM. There are number of techniques available at preprocessing level of WUM such as data cleaning; data filtering; user identification; session identification and session clustering. In this research paper, a complete preprocessing technique is being proposed to preprocess the web log for extraction of user patterns. Data cleaning algorithm removes the irrelevant entries from web log and filtering algorithm discards the uninterested attributes from log file. User and sessions are identified. Proposed hierarchical sessionization algorithm generates the hierarchy of sessions. We obtain unbiased hierarchical clusters from the web log file. © 2010 IEEE.
Mehdi N.,National University of Sciences and Technology |
Rehan M.,Pakistan Institute of Engineering and Applied Sciences |
Malik F.M.,National University of Sciences and Technology |
Bhatti A.I.,Muhammad Ali Jinnah University |
Tufail M.,Pakistan Institute of Engineering and Applied Sciences
ISA Transactions | Year: 2014
This paper describes the anti-windup compensator (AWC) design methodologies for stable and unstable cascade plants with cascade controllers facing actuator saturation. Two novel full-order decoupling AWC architectures, based on equivalence of the overall closed-loop system, are developed to deal with windup effects. The decoupled architectures have been developed, to formulate the AWC synthesis problem, by assuring equivalence of the coupled and the decoupled architectures, instead of using an analogy, for cascade control systems. A comparison of both AWC architectures from application point of view is provided to consolidate their utilities. Mainly, one of the architecture is better in terms of computational complexity for implementation, while the other is suitable for unstable cascade systems. On the basis of the architectures for cascade systems facing stability and performance degradation problems in the event of actuator saturation, the global AWC design methodologies utilizing linear matrix inequalities (LMIs) are developed. These LMIs are synthesized by application of the Lyapunov theory, the global sector condition and the 2 gain reduction of the uncertain decoupled nonlinear component of the decoupled architecture. Further, an LMI-based local AWC design methodology is derived by utilizing a local sector condition by means of a quadratic Lyapunov function to resolve the windup problem for unstable cascade plants under saturation. To demonstrate effectiveness of the proposed AWC schemes, an underactuated mechanical system, the ball-and-beam system, is considered, and details of the simulation and practical implementation results are described. © 2014 ISA.
Masood T.,Muhammad Ali Jinnah University |
Nadeem A.,Muhammad Ali Jinnah University |
Ali S.,Muhammad Ali Jinnah University
ICET 2013 - 2013 IEEE 9th International Conference on Emerging Technologies | Year: 2013
As web services are dynamic in natures, the process of maintenance and evolution is rapid for web services. In order to verify the impact of changes, retesting of web services is required. Testing of web services is difficult because only web service provider has the source code and both web service user and broker have WSDL specification of the service. In this paper we have extended an existing specification based regression testing of web services approach. Both original and modified WSDL specifications are compared for identification of operation level changes. Our regression test selection approach is safe as all the relevant test cases are selected as reusable. © 2013 IEEE.