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181.
Hafiz Shehzad Ahmed Hong-Dong Zhao Munawar Hussain Jing Wang 《Pattern Recognition and Image Analysis》2017,27(4):804-809
Image processing algorithm is implemented to detect the grain boundary of the crystal using (SEM) Scanning Electron Microscopy. This paper presents a method for edge-detection in color image based on Sobel, Canny operator’s algorithm and discrete wavelet transform. The performance of these methods is effective and faster. Filtering is another approach to clear the noise of an image. Scanning Electron Microscopy (SEM) used to inspect semiconductor materials and devices for several decades, continues to increase in importance. Removal of noise is an important step in the image restoration process, but de-noising of the image has remained a challenging problem in recent research associated with image process. De-noising is used to remove the noise from corrupted images, while retaining the edges and other detailed features too are an essential part of de-noising. 相似文献
182.
M. Syed Ali S. Saravanan M. Esther Rani S. Elakkia Jinde Cao Ahmed Alsaedi Tasawar Hayat 《Neural Processing Letters》2017,46(3):991-1007
This paper is concerned with the problem of asymptotic stability of neutral type Cohen–Grossberg BAM neural networks with discrete and distributed time-varying delays. By constructing a suitable Lyapunov–Krasovskii functional (LKF), reciprocal convex technique and Jensen’s inequality are used to delay-dependent conditions are established to analysis the asymptotic stability of Cohen–Grossberg BAM neural networks with discrete and distributed time-varying delays. These stability conditions are formulated as linear matrix inequalities (LMIs) which can be easily solved by various convex optimization algorithms. Finally numerical examples are given to illustrate the usefulness of our proposed method. 相似文献
183.
Murad Khan Awais Ahmad Shehzad Khalid Syed Hassan Ahmed Sohail Jabbar Jamil Ahmad 《Multimedia Tools and Applications》2017,76(23):24649-24674
Vertical handover gain significant importance due to the enhancements in mobility models by the Fourth Generation (4G) technologies. However, these enhancements are limited to specific scenarios and hence do not provide support for generic mobility. Similarly, various schemes are proposed based on these mobility models but most of them are suffered from the high packet loss, frequent handovers, too early and late handovers, inappropriate network selection, etc. To address these challenges, a generic vertical handover management scheme for heterogeneous wireless networks is proposed in this article. The proposed scheme works in three phases. In the first phase, a handover triggering approach is designed to identify the appropriate place for initiating handover based on the estimated coverage area of a WLAN access point or cellular base station. In the second phase, fuzzy rule based system is designed to eliminate the inappropriate networks before deciding an optimal network for handover. In the third phase, a network selection scheme is developed based on the Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) decision mechanism. Various parameters such as delay, jitter, Bit Error Rate (BER), packet loss, communication cost, response time, and network load are considered for selecting an optimal network. The proposed scheme is tested in a mobility scenario with different speeds of a mobile node ranging from very low to very high. The simulation results are compared with the existing decision models used for network selection and handover triggering approaches. The proposed scheme outperforms these schemes in terms of energy consumption, handover delay and time, packet loss, good put, etc. 相似文献
184.
Ahmed?I.?Saleh Mohammed?F.?Al?Rahmawy Arwa?E.?AbulwafaEmail author 《World Wide Web》2017,20(5):939-993
World Wide Web is a continuously growing giant, and within the next few years, Web contents will surely increase tremendously. Hence, there is a great requirement to have algorithms that could accurately classify Web pages. Automatic Web page classification is significantly different from traditional text classification because of the presence of additional information, provided by the HTML structure. Recently, several techniques have been arisen from combinations of artificial intelligence and statistical approaches. However, it is not a simple matter to find an optimal classification technique for Web pages. This paper introduces a novel strategy for vertical Web page classification, which is called Classification using Multi-layered Domain Ontology (CMDO). It employs several Web mining techniques, and depends mainly on proposed multi-layered domain ontology. In order to promote the classification accuracy, CMDO implies a distiller to reject pages related to other domains. CMDO also employs a novel classification technique, which is called Graph Based Classification (GBC). The proposed GBC has pioneering features that other techniques do not have, such as outlier rejection and pruning. Experimental results have shown that CMDO outperforms recent techniques as it introduces better precision, recall, and classification accuracy. 相似文献
185.
Lingzhi Zhao Jinde Cao Chengdai Huang Ahmed Alsaedi Abdullah Al-Barakati Habib M. Fardoun 《International Journal of Control, Automation and Systems》2017,15(3):1134-1144
The issue of bifurcation control for a delayed fractional network involving two neurons is concerned. Delay-dependent stability conditions and the bifurcation point are established by discussing the associated characteristic equation of the proposed network. Then, a delayed feedback controller is firstly designed to stabilize the Hopf bifurcation, and desirable dynamics is achieved. It is indicated that the designed controller is extremely effective which can postpone the onset of bifurcation by carefully selecting the feedback gain. Finally, simulation results are given to verify the efficiency of the theoretical results. 相似文献
186.
Rob J. Hyndman Roman A. Ahmed George Athanasopoulos Han Lin Shang 《Computational statistics & data analysis》2011,55(9):2579-2589
In many applications, there are multiple time series that are hierarchically organized and can be aggregated at several different levels in groups based on products, geography or some other features. We call these “hierarchical time series”. They are commonly forecast using either a “bottom-up” or a “top-down” method.In this paper we propose a new approach to hierarchical forecasting which provides optimal forecasts that are better than forecasts produced by either a top-down or a bottom-up approach. Our method is based on independently forecasting all series at all levels of the hierarchy and then using a regression model to optimally combine and reconcile these forecasts. The resulting revised forecasts add up appropriately across the hierarchy, are unbiased and have minimum variance amongst all combination forecasts under some simple assumptions.We show in a simulation study that our method performs well compared to the top-down approach and the bottom-up method. We demonstrate our proposed method by forecasting Australian tourism demand where the data are disaggregated by purpose of travel and geographical region. 相似文献
187.
A real-time database systemhas temporal consistency constraints in addition to timing constraints.The timing constraints require a transaction to be completedby a specified deadline, and the temporal consistency constraintsrequire that temporal data read by a transaction be up-to-date.If a transaction reads out-of-date data, it will become temporallyinconsistent. A real-time database system consists of differenttypes of temporal data objects, including derived objects. Thevalue of a derived object is computed from a set of other objects,known as the read-set of the derived object. The derived objectmay not always reflect the current state of its read-set; a derivedobject can become out-of-date even if its read-set is up-to-date.Any subsequent transaction reading the derived object will thenbecome temporally inconsistent. In this case, in order to readup-to-date objects, a transaction will have to wait until someother transaction updates the out-of-date object. However, indoing so, the waiting transaction may miss its deadline, particularlyif the update is not periodic but instead arrives randomly. Wepropose to update the outdated objects so that not only is thetemporal consistency improved, but also the number of misseddeadlines does not increase significantly, and as a result thereis an overall improvement in the performance of the system. Wepropose, implement and study a novel approach, to be known astriggered updates, to improve temporal consistency in firm real-timedatabase systems when updates are not periodic. We identify propertiesof triggered updates and explain how they work by giving bothan intuitive and a probabilistic analysis. We present strategiesfor generating triggered updates, discuss their suitability invarious contexts and perform a detailed simulation study to evaluatetheir performance. Results show that it is possible to improvetemporal consistency without degrading the timeliness of real-time database systems to a great deal. 相似文献
188.
In this study, the effect of the centrifugal forces on the eigenvalue solution obtained using two different nonlinear finite
element formulations is examined. Both formulations can correctly describe arbitrary rigid body displacements and can be used
in the large deformation analysis. The first formulation is based on the geometrically exact beam theory, which assumes that the cross section does not deform in its own plane and remains plane after deformation. The second formulation,
the absolute nodal coordinate formulation (ANCF), relaxes this assumption and introduces modes that couple the deformation of the cross section and the axial and bending
deformations. In the absolute nodal coordinate formulation, four different models are developed; a beam model based on a general
continuum mechanics approach, a beam model based on an elastic line approach, a beam model based on an elastic line approach
combined with the Hellinger–Reissner principle, and a plate model based on a general continuum mechanics approach. The use
of the general continuum mechanics approach leads to a model that includes the ANCF coupled deformation modes. Because of these modes, the continuum mechanics model differs from the models based on the elastic line approach. In both
the geometrically exact beam and the absolute nodal coordinate formulations, the centrifugal forces are formulated in terms
of the element nodal coordinates. The effect of the centrifugal forces on the flap and lag modes of the rotating beam is examined, and the results obtained using the two formulations are compared for different values of
the beam angular velocity. The numerical comparative study presented in this investigation shows that when the effect of some
ANCF coupled deformation modes is neglected, the eigenvalue solutions obtained using the geometrically exact beam and the
absolute nodal coordinate formulations are in a good agreement. The results also show that as the effect of the centrifugal
forces, which tend to increase the beam stiffness, increases, the effect of the ANCF coupled deformation modes on the computed
eigenvalues becomes less significant. It is shown in this paper that when the effect of the Poisson ration is neglected, the
eigenvalue solution obtained using the absolute nodal coordinate formulation based on a general continuum mechanics approach
is in a good agreement with the solution obtained using the geometrically exact beam model. 相似文献
189.
Shameem Ahmed Moushumi Sharmin Sheikh I. Ahamed 《Universal Access in the Information Society》2008,7(4):273-283
Universal access from a handheld device (such as a PDA, cell phone) at any time or anywhere is now a reality. Ubicomp Assistant
(UA) (Sharmin et al. in Proceedings of the 21st annual ACM symposium on applied computing (ACM SAC 2006), Dijon, France, pp
1013–1017, 2006) is an integral service of MARKS (Sharmin et al. in Proceedings of the third international conference on information
technology: new generations (ITNG 2006), Las Vegas, Nevada, USA, pp 306–313, 2006). It is a middleware developed for handheld
devices, and has been designed to accommodate different types of users (e.g., education, healthcare, marketing, or business).
This customizable service employs the ubiquitous nature of current short range, low-power wireless connectivity and readily
available, low-cost lightweight mobile devices. These devices can reach other neighbouring devices using a free short-range
ad hoc network. To the best of the authors’ knowledge, the UA service is the only service designed for these devices. This
paper presents the details of Ubi-App, a ubiquitous application for universal access from any handheld device, which uses
UA as a service. The results of a usability test and performance evaluation of the prototype show that Ubi-App is useful,
easy to use, easy to install, and does not degrade the performance of the device. 相似文献
190.
N.?U.?Ahmed C.?D.?CharalambousEmail author 《Mathematics of Control, Signals, and Systems (MCSS)》2007,19(1):65-91
In this paper, we consider minimax games for stochastic uncertain systems with the pay-off being a nonlinear functional of
the uncertain measure where the uncertainty is measured in terms of relative entropy between the uncertain and the nominal
measure. The maximizing player is the uncertain measure, while the minimizer is the control which induces a nominal measure.
Existence and uniqueness of minimax solutions are derived on suitable spaces of measures. Several examples are presented illustrating
the results. Subsequently, the results are also applied to controlled stochastic differential equations on Hilbert spaces.
Based on infinite dimensional extension of Girsanov’s measure transformation, martingale solutions are used in establishing
existence and uniqueness of minimax strategies. Moreover, some basic properties of the relative entropy of measures on infinite
dimensional spaces are presented and then applied to uncertain systems described by a stochastic differential inclusion on
Hilbert space. An explicit expression for the worst case measure representing the maximizing player (adversary) is found. 相似文献