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Khan R.,Queen's University of Belfast | Khan S.U.,CECOS University of IT and Emerging Sciences
Sustainable Computing: Informatics and Systems | Year: 2017

Network end-user devices such as laptops and desktop PCs are often left powered ON 24/7 while they remain idle most of the time. The main reason behind this is maintaining network connectivity for remote access, VoIP, instant messaging and other Internet-based applications. The Network Connectivity Proxy (NCP) emerged as a quite promising strategy for significantly reducing network energy waste by allowing devices to sleep without losing their presence over Internet. It impersonates presence of devices during their sleeping periods at all layers of TCP/IP stack. The NCP can successfully proxy basic networking protocols (e.g., ARP, PING, DHCP, etc.) but faces challenges in proxying TCP sessions and proprietary closed-source applications with encrypted packets. To overcome the limitations of NCP concept, this paper proposes a new strategy for reducing network energy waste through intelligent coordination among a user's devices (e.g., smartphone, laptop, desktop PC, etc.). In the proposed system, a user's daily used devices autonomously and seamlessly communicate with a centralized control server that decides which user device will maintain presence of applications at a given instant. To allow devices to sleep and wake them up whenever necessary, the proposed system also uses a light-weight Home Gateway Proxy (HGP) with very basic set of practically realizable features. The communication framework for HGP is designed to achieve auto-discovery, seamless networking and communication features. This paper also practically evaluates the proposed system and estimates energy saving for fixed as well as mobile network devices. © 2017 Elsevier Inc.


Rashid A.,University of Peshawar | Shah S.,University of Peshawar | Rehman A.,CECOS University of IT and Emerging Sciences
ICOSST 2016 - 2016 International Conference on Open Source Systems and Technologies, Proceedings | Year: 2016

Ring core flux gate compass is cheap and reliable solution for measurement of magnetic north of movable platforms. It finds its applications in variety of underwater applications. Prior to its use, the compass needs to be calibrated in a nonmagnetic environment which is prone to errors due to environmental conditions such as test location and on board components. The paper discusses the quick and easy way of calibrating the compass in a lab environment by comparison method. The already calibrated compass is used as a master compass. The Master compass data is taken as reference and under the same environmental conditions the compass under test is calibrated thus the errors due to the environment are eliminated. © 2016 IEEE.


Izhar,CECOS University of IT and Emerging Sciences | Khan F.U.,University of Peshawar
2016 International Conference on Intelligent Systems Engineering, ICISE 2016 | Year: 2016

Helmholtz resonator (HR) is the key element of acoustic energy harvesting devices. It is used to augment or attenuate the incoming acoustic wave. In acoustic energy harvesters the objective of HR is to augment the incoming acoustic wave. In this work an improved architecture of HR is proposed for acoustic energy harvesting devices. Modeling and simulation of the HR is reported. The HR is modeled as one degree of freedom system. The proposed HR has a high pressure gain as compared to the HR used in previously developed acoustic energy harvesting devices. The proposed design for HR results in high acoustic stiffness of the air entrapped inside the Helmholtz cavity that ultimately improves the pressure gain of the HR. Moreover, for similar dimensions the resonant frequency of the proposed HR is 1693 Hz, while resonant frequency of the reported HRs is 1119.7 Hz. Furthermore, at resonance the pressure gain of the proposed HR is 56.5 dB which is quite high than the pressure gain of the reported HRs with cylindrical shape cavities that is 52.7 dB. © 2016 IEEE.


Khan R.,Queen's University of Belfast | Khan S.U.,CECOS University of IT and Emerging Sciences
Procedia Computer Science | Year: 2016

Several studies in the past have revealed that network end user devices are left powered up 24/7 even when idle just for the sake of maintaining Internet connectivity. Network devices normally support low power states but are kept inactive due to their inability to maintain network connectivity. The Network Connectivity Proxy (NCP) has recently been proposed as an effective mechanism to impersonate network connectivity on behalf of high power devices and enable them to sleep when idle without losing network presence. The NCP can efficiently proxy basic networking protocol, however, proxying of Internet based applications have no absolute solution due to dynamic and non-predictable nature of the packets they are sending and receiving periodically. This paper proposes an approach for proxying Internet based applications and presents the basic software architectures and capabilities. Further, this paper also practically evaluates the proposed framework and analyzes expected energy savings achievable under- different realistic conditions. © 2016 The Authors.


Zafar M.S.,Taibah University | Ahmed N.,CECOS University of IT and Emerging Sciences
Technology and Health Care | Year: 2014

OBJECTIVES: The anisotropic natures of dental tissues result in variable properties from one point to the other within the same tooth. The aim of this study was to analyze deciduous incisors enamel and dentin for elastic modulus and hardness. In addition, retained deciduous incisors were assessed to compare properties with exfoliated teeth. METHODS: Deciduous mandibular incisors either exfoliated at physiological age or retained were included in this study. Samples were prepared by dissecting teeth in transverse sections and surfaces under investigation were prepared and polished for nanoindentation. Nanoindentation was performed at multiple sites using Hysitron [TI 725 Ubi] testing instrument. Data analysis was performed using SPSS software (version 20) to calculate absolute hardness and elastic modulus. The statistical significance was calculated using the t-test. RESULTS: The hardness of human deciduous incisor varies between 0.01-7 GPa. The highest value of hardness was observed for the incisal edge (5.09 ± 0.64 GPa) followed by mid-surface enamel and cervical enamel. The hardness of mantle dentin was (0.56 ± 0.19 GPa) and the inner dentin was (0.34 ± 0.12 GPa). CONCLUSIONS: The average hardness of primary teeth enamel is lower than permanent teeth enamel. The hardness of retained teeth enamel is greater than exfoliated teeth however lower than permanent teeth enamel of the equivalent region. © 2014 - IOS Press and the authors.


Zafar M.S.,Taibah University | Ahmed N.,CECOS University of IT and Emerging Sciences
Fluoride | Year: 2015

Because topical fluoride is considered to be beneficial for oral health, fluoride release and recharge features have been added to various restorative dental materials. These materials act as a rechargeable reservoir that can release fluoride, be recharged with fluoride, and then re-release fluoride, thus ensuring the availability of fluoride over a longer period of time. The ability of these materials to deliver the optimal concentration of fluoride required for various therapeutic actions for dental health has resulted in their popularity. This paper reviews the fluoride releasing materials and the therapeutic effects of the released fluoride. © 2015, The International Society for Fluoride Research Inc.


Khan F.,University of Peshawar | Izhar,CECOS University of IT and Emerging Sciences
Journal of Renewable and Sustainable Energy | Year: 2016

This paper reports an improved acoustic energy harvester with a tapered Helmholtz cavity. The harvester consists of a bimorph piezoelectric composite plate and a Helmholtz resonator (HR) with a tapered cavity. The architecture, operational mechanism, fabrication, and characterization of the harvesters are described. The harvesters are tested under sinusoidal sound pressure levels (SPLs) inside a lab as well as random SPLs in a real ambient acoustical environment. When a harvester with a tapered HR and without proof mass attached to its piezoelectric plate is characterized at a sinusoidal SPL of 130 dB, a maximum power of 90.6 μW is delivered to 1 kΩ load. In comparison, a similar harvester with a cylindrical shape HR produced a maximum power of 51.4 μW under the similar acoustic conditions. It is found that 76.26% increase in power is achieved with the tapered cavity for the HR. Furthermore, due to the attachment of a proof mass (0.84 g) with the harvester, its power production capability is further increased by 103.3%, from 90.6 to 184.18 μW. Moreover, in a real environment, the maximum voltage amplitudes of about 260 and 280 mV are produced by the harvester when placed in the surrounding of a motorbike and domestic electric generator, respectively. © 2016 Author(s).


Ullah N.,CECOS University of IT and Emerging Sciences
Software Quality Journal | Year: 2015

Nowadays many commercial projects use open source applications or components (OSS). A recurring problem is therefore the selection of the most appropriate OSS for a project. A relevant criterion for selection is the reliability of the OSS. In this paper, we propose a method that selects the software reliability growth model (SRGM), which among several alternative models best predicts the reliability of the OSS, in terms of residual defects. Several methods exist for predicting residual defects in software, and a widely used method is SRGM. SRGM has underlying assumptions, which are often violated in practice, but empirical evidence has shown that many models are quite robust despite these assumption violations. However, within the SRGM family, many models are available, and it is often difficult to know which models are better to apply in a given context. We present an empirical method that applies various SRGMs iteratively on OSS defect data and selects the model which best predicts the residual defects of the OSS. We empirically validate the method by applying it to defect data collected from 21 different releases of 7 OSS projects. The results show that the method helps in selecting the best model among several alternative models. The method selects the best model 17 times out of 21. In the remaining 4, it selects the second best model. © 2014, Springer Science+Business Media New York.


Maurotto A.,University of Sheffield | Siemers C.,TU Braunschweig | Muhammad R.,CECOS University of IT and Emerging Sciences | Roy A.,Loughborough University | Silberschmidt V.,Loughborough University
Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science | Year: 2014

Metastable β-titanium alloys such as Ti 15V 3Al 3Cr 3Sn are of great technological interest thanks to their high fatigue strength-to-density ratio. However, their high hardness and poor machinability increase machining costs. Additionally, formation of undesirable long chips increases the machining time. To address those issues, a metastable β-titanium alloy (Ti 15V 3Al 3Cr 2Zr 0.9La) with enhanced machinability was developed to produce short chips even at low cutting speeds. A hybrid ultrasonically assisted machining technique, known to reduce cutting forces, was employed in this study. Cutting force components and surface quality of the finished work-pieces were analyzed for a range of cutting speeds in comparison with those for more traditional Ti 15V 3Al 3Cr 3Sn. The novel alloy demonstrated slightly improved machining characteristics at higher cutting speeds and is now ready for industrial applications. © 2014 The Minerals, Metals , Materials Society and ASM International.


Khan Z.W.,CECOS University of IT and Emerging Sciences | Khan S.,University of Peshawar
Proceedings of 2015 International Conference on Emerging Technologies, ICET 2015 | Year: 2015

The structure of electric power system is under development process due to rapid increase in energy demands all over the world. With great advancements in technologies and concerns about environmental effects, utilities are moving towards interconnection of Distributed Generation (DG) in the distribution networks. Apart from environmental advantages, DG's can have significant impacts on the power system depending on type of DG unit and its interconnection with the distribution network. In this research paper, the impacts of DG on voltage profile and power losses are investigated on a practical radial distribution network with four cases of DG interconnection. With each case, the performances of interconnected DG in terms of voltage and power losses are analyzed through simulation in Electrical Transient Analyzer Program (ETAP). The location of coupling and size of interconnected DG is used as a parameter in order to verify the effects on these issues. Detailed simulations are conducted in order to explain and verify the results. It is found that there is significant improvement in bus voltages and power loss reduction depending on appropriate size and feasible locations of DGs interconnection. © 2015 IEEE.

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