Kaloi G.S.,Shanghai JiaoTong University |
Wang J.,Shanghai JiaoTong University |
Baloch M.H.,Mehran UET
Journal of Electrical Engineering and Technology | Year: 2016
This paper presents a dynamic modeling and control of doubly fed induction-generator (DFIG) based variable speed wind-turbine. The dynamic model of DFIG is incorporated with all system components which provide simple design and controls. The penetration of wind power is increasing into electrical networks, which necessitates more comprehensive studies to recognize the interaction between the wind farms and the power grid. This paper presents the dynamic model of a DFIG based wind turbine connected to the grid system in the dq-synchronous reference frame. In this article, the feedback linearization method has proposed a controller in order to reduce the oscillation and stabilize the wind turbine system parameters based on feedback linearization concepts. Based on the nonlinear control system, the proposed approach is applied to the rotor side converter and grid side converter. The damping of the DFIG is improved in transient response. In addition, the oscillation of the stator current and DC link voltage during the generator voltage dip are reduced. To the best of author’s knowledge, the proposed control outcomes compared with conventional controller verified the effectiveness, having better performance through simulation tool Matlab. © The Korean Institute of Electrical Engineers.
Aziz Z.,Mehran UET |
Qureshi U.M.,Mehran UET |
Shaikh F.K.,Mehran UET |
Shaikh F.K.,TU Darmstadt |
And 3 more authors.
2014 IEEE 16th International Conference on e-Health Networking, Applications and Services, Healthcom 2014 | Year: 2015
The reliable delivery of data is important in designing Wireless Body Area Networks (WBANs) employed for critical applications such as e-health. In order to communicate the data reliably from the sensors to the base station, the data transmission technique (star or multi-hop) and the transmission power plays a very important role. As transmission power is increased, transmission distance is increased and the data can be sent reliably to far nodes. However, in WBANs, there is always a limit to increase the transmission power. Keeping the power level at some low threshold and increasing the distance between a sensor and the base station results in reduced received power which ultimately degrades the data transmission. Thus, for star data transmission technique, the point to ponder is the maximum separation between a sensor and the base station to transmit the data reliably. The reliability in WBANs can be analyzed through different parameters such as received power, received signal strength indicator, link quality indicator, packet error rate, packet reception rate, etc. This paper aims at performing a reliability analysis for WBAN through the mentioned parameters to suggest an optimal sensor/base station separation using star data transmission technique. This analysis is performed employing the default routing protocol in TinyOS called the Collection Tree Protocol. Our study considers different sensor placements on different parts of the body as well as different angular offsets between sensor and base station. © 2014 IEEE.
Ali M.A.,Sukkur IBA |
Kumar W.,Mehran UET |
Arif M.,Mehran UET
2016 IEEE 6th International Conference on Communications and Electronics, IEEE ICCE 2016 | Year: 2016
Direct conversion transceivers are the preferred choice for the RF front-end in modern communication devices. They are simple and cheap to implement but for the case of sensitive multicarrier systems these devices may not maintain the required level of performance as regards image rejection (IR), carrier frequency offset (CFO) and direct current offset. In the presence of this non-ideal behaviour it is not possible to achieve a high signal to interference ratio (SIR). This situation necessitates the use of DSP schemes to efficiently mitigate these effects and also to relax the stringent requirements on transceiver design. In this paper we study the design of a receiver architecture which can jointly estimate the channel impulse response (CIR) as well as transmit and receive (Tx/Rx) IQ imbalance. We have proposed a simple system model for two-step iterative channel and IQ imbalance estimation using long training sequences (LTS) which are already a part of WLAN standards. In summary the proposed scheme provides an excellent low complexity solution for joint channel and Tx/Rx IQ imbalance parameter estimation. © 2016 IEEE.
Korai M.S.,Institute of Environmental Engineering & Management |
Mahar R.B.,Us Pakistan Center For Advance Studies In Water Us Pacasw |
Uqaili M.A.,Mehran UET
Energy Conversion and Management | Year: 2016
Improper disposal of municipal solid waste (MSW) has created many environmental problems in Pakistan and the country is facing energy shortages as well. The present study evaluates the biochemical and thermochemical treatment options of MSW in order to address both the endemic environmental challenges and in part the energy shortage. According to the nature of waste components, a number of scenarios were developed to optimize the waste to energy (WTE) routes. The evaluation of treatment options has been performed by mathematical equations using the special characteristics of MSW. The power generation potential (PGP) of biochemical (anaerobic digestion) has been observed in the range of 5.9–11.3 kW/ton day under various scenarios. The PGP of Refuse Derived Fuel (RDF), Mass Burn Incinerator (MBI), Gasification/Pyrolysis (Gasi./Pyro.) and Plasma Arc Gasification (PAG) have been found to be in the range of 2.7–118.6 kW/ton day, 3.8–164.7 kW/ton day, 4.2–184.5 kW/ton day and 5.2–224 kW/ton day, respectively. The highest values of biochemical and all thermochemical technologies have been obtained through the use of scenarios including the putrescible components (PCs) of MSW such as food and yard wastes, and the non-biodegradable components (NBCs) of MSW such as plastic, rubber, leather, textile and wood respectively. Therefore, routes which include these components are the optimized WTE routes for maximum PGP by biochemical and thermochemical treatments of MSW. The findings of study lead to recommend that socio-economic and environmental feasibility of WTE conversion technologies should be performed in the context of the country. © 2016 Elsevier Ltd
Siddiqui I.F.,Mehran UET |
Siddiqui I.F.,Hanyang University |
Faseeh N.M.,Sungkyunkwan University |
Lee S.U.J.,Hanyang University |
Unar M.A.,Mehran UET
Communications in Computer and Information Science | Year: 2014
Botnets have become one of the most solemn threats to Internet security. Botnets comprises over a network of infected nodes known as ‘bot’. Bots are controlled by human operators (botmasters). Random nature of Peerto-Peer botnets has influenced sinkhole researchers to compromise over occupation of hunted command and control in a complex manner and due to variable nature of action, they are often good deserters. In this paper, we present a design of an advanced hyper-efficient mechanism which has the ability to pursue Peerto-Peer randomized botnets. It provides capacity to detain targeted sinkholes and identify arbitrary execution of contagion in infected nodes. In the end, method acquires the composition of different cubic formations for proper lookup of random natured Peer-to-Peer botnets. © Springer International Publishing Switzerland 2014.
Memon S.,Mehran UET |
Jokhio I.A.,Mehran UET |
Arisar S.H.,Mehran UET |
Lech M.,RMIT University |
Maddage N.,RMIT University
IETE Journal of Research | Year: 2012
Gaussian Mixture Model (GMM)-based speaker models yield very good performance in text-independent speaker verification systems. GMMs use expectation maximization (EM) as an optimization procedure to train speaker models. This paper proposes the information theoretic expectation maximization (ITEM) with improved convergence rates to train the speaker models. The approach amounts to information theoretic (IT) since it uses the parzen density estimation and Kullback-Leibler (KL) divergence measure. EM encounters the problem of convergence thus to enhance the convergence rates of EM, an IT procedure is incorporated. The proposed ITEM algorithm adapts means, covariances, and weights, like the conventional EM algorithm; however, this process is not conducted directly on feature vectors but on a smaller set of centroids derived by the IT procedure, which simultaneously minimizes the divergence between the Parzen estimates of the feature vector's distribution within a given class and the centroids distribution within the same class. The ITEM algorithm was applied to the speaker verification problem using NIST 2001, 2002, 2004, and 2006 speaker recognition evaluation corpora and MFCC with delta, energy, and zero-crossing features. The results showed an improvement of the equal error rate over the classical EM approach. The ITEM method also showed higher convergence rates compare with the EM method.
Rajput O.,Mehran UET |
Qureshi S.,Mehran UET |
Solangi A.R.,Mehran UET |
Aziz Z.,Mehran UET |
Shaikh F.K.,Mehran UET
2013 5th International Conference on Information and Communication Technology for the Muslim World, ICT4M 2013 | Year: 2013
Wireless Body Area Network has been identified as a promising technology for supporting health-care, elderly care and visually impaired people. Crowd detection is one of the main issues in navigating the blind people across the known and unknown terrains. The visually impaired person will be equipped with sensors which will detect human crowd and alert the person accordingly. This paper attempts to comprehensively review all the research and development to serve visually impaired persons. A variety of strategies, sensors, communication standards and data transmission techniques are analyzed and compared according to their accuracy, compactness, computation performance and cost. The intention of this survey is not to criticize, but to provide reference to future research and development. © 2013 IEEE.
Rauf Ab.,Mehran UET |
Faisal H.,Mehran UET |
Asadullah M.,Mehran UET
IET Conference Publications | Year: 2015
Methane Hydrates is the future of natural gas to meet its growing needs. For decades, gas hydrates have been discussed as a potential resource, particularly for countries with limited access to conventional hydrocarbons. But now it is of prime importance to know the value of Ice that burns and follow the Japan Oil, Gas, and Metals National Corporation techniques to produce methane hydrates. Methane hydrates are a potential energy resource: A frequently quoted estimate of the global methane hydrate resource is 20,000 trillion cubic meters, or about 700,000 Tcf. However, only a small portion of this enormous resource should be harvested as an energy fuel.
Memon R.A.,Mehran UET |
Khaskheli G.B.,Mehran UET |
Dahani M.A.,National Highway Authority
International Journal of Civil Engineering | Year: 2012
Present study is an extension of earlier work carried out on two-lane two way roads in the two provinces of Pakistan i.e. N-25, N-55 and N-5 regarding the measure of operating speed and development of operating speed prediction models. Curved sections of two-lane rural highways are the main location of run-off road accidents. In addition to that the road alignment having combination of geometric elements may be more harmful to the drivers than the successive features with adequate separation. This study is carried out on two-lane two-way road along N-65 (from Sibi to Quetta). Three sections are selected for study with thirty three horizontal curves. Continuous speed profile data was recorded with the help of VBox (GPS based device) which was attached with a vehicle to detect vehicle position through satellite signals. VBox is new equipment with modern technology in this field and it helps in recording continuous speed profile and saving of this information on the computer as a permanent record. Through the regression analysis, models were developed for estimation of operating speed on horizontal curves and on tangent, and estimation of maximum speed reduction from tangent to curve. The validation of developed model shows compatibility with the experimental data.
Mahar F.,Iqra University |
Ali S.A.,Iqra University |
Hussain A.,Korea University |
Bhutto Z.,Mehran UET
International Conference on Control, Automation and Systems | Year: 2011
Thus far, researchers test several heuristic in order to produce the optimal solutions of the cost function and controller parameters. In this paper, an implementation of the Ant Colony Optimization (ACO) algorithm for the optimization of cost function and controller parameters has been discussed. To implement the ACO algorithm with a problem requires defining; cost function and the constraint. All simulation has been performed using a software program developed in the MATLAB environment. The simulation results show that ACO algorithm can be used to counterbalance the effect and improve the performance of any control system. Moreover, the proposed scheme overcomes the weaknesses of conventional fixed gain controller and improvement is accomplished in terms of settling time, oscillations and overshoot. © 2011 ICROS.