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101.
Mahdi Hasanipanah Majid Noorian-Bidgoli Danial Jahed Armaghani Hossein Khamesi 《Engineering with Computers》2016,32(4):705-715
The potential surface settlement, especially in urban areas, is one of the most hazardous factors in subway and other infrastructure tunnel excavations. Therefore, accurate prediction of maximum surface settlement (MSS) is essential to minimize the possible risk of damage. This paper presents a new hybrid model of artificial neural network (ANN) optimized by particle swarm optimization (PSO) for prediction of MSS. Here, this combination is abbreviated using PSO-ANN. To indicate the performance capacity of the PSO-ANN model in predicting MSS, a pre-developed ANN model was also developed. To construct the mentioned models, horizontal to vertical stress ratio, cohesion and Young’s modulus were set as input parameters, whereas MSS was considered as system output. A database consisting of 143 data sets, obtained from the line No. 2 of Karaj subway, in Iran, was used to develop the predictive models. The performance of the predictive models was evaluated by comparing performance prediction parameters, including root mean square error (RMSE), variance account for (VAF) and coefficient correlation (R 2). The results indicate that the proposed PSO-ANN model is able to predict MSS with a higher degree of accuracy in comparison with the ANN results. In addition, the results of sensitivity analysis show that the horizontal to vertical stress ratio has slightly higher effect of MSS compared to other model inputs. 相似文献
102.
A. R. Elshazly M. E. Nasr M. M. Fouad F. S. Abdel-Samie 《International Journal of Speech Technology》2017,20(4):951-958
Digital watermarking technology is concerned with solving the problem of copyright protection, data authentication, content identification, distribution, and duplication of the digital media due to the great developments in computers and Internet technology. Recently, protection of digital audio signals has attracted the attention of researchers. This paper proposes a new audio watermarking scheme based on discrete wavelet transform (DWT), singular value decomposition (SVD), and quantization index modulation (QIM) with a synchronization code embedded with two encrypted watermark images or logos inserted into a stereo audio signal. In this algorithm, the original audio signal is split into blocks, and each block is decomposed with a two-level DWT, and then the approximate low-frequency sub-band coefficients are decomposed by SVD transform to obtain a diagonal matrix. The prepared watermarking and synchronization code bit stream is embedded into the diagonal matrix using QIM. After that, we perform inverse singular value decomposition (ISVD) and inverse discrete wavelet transform (IDWT) to obtain the watermarked audio signal. The watermark can be blindly extracted without knowledge of the original audio signal. Experimental results show that the transparency and imperceptibility of the proposed algorithm is satisfied, and that robustness is strong against popular audio signal processing attacks. High watermarking payload is achieved through the proposed scheme. 相似文献
103.
Investigation of the effects of nonisothermal suspension polymerization of vinyl chloride on the fusion and degradation behavior of poly(vinyl chloride) 下载免费PDF全文
Thermal stability of poly(vinyl chloride) (PVC) samples polymerized under a temperature trajectory was studied from the point of view of morphological and microstructural characteristics. The results are compared with those of the PVC samples obtained by polymerization at constant temperature having the same K value. The Brabender® plastograph data indicated that the final PVC synthesized with the temperature trajectory showed lower fusion time and higher thermal stability time. The nonisothermal condition also increased the degree of fusion of the final PVC resin, reflecting lower temperature/time required to process it. It was found that the thermal stability of nonisothermally produced PVC as characterized by dehydrochlorination rate decreased (improved) with the increasing monomer conversion until a minimum value was reached that corresponded to the conversion at the pressure drop. However, the dehydrochlorination rate remains almost constant with conversion for an isothermal grade PVC resin. Although the evolution of the number of internal double bonds as well as extent of discoloration of PVC with conversion shows a decreasing trend, the labile chlorine concentration exhibits a maximum at early conversion. The reason for the former can be explained by the temperature dependence of reactions forming defect structures, which are kinetically controlled and thus favored at higher temperatures. The latter, however, can be explained because of the increasing importance of transfer reactions to polymer with increasing polymer concentration. Finally, the results from differential thermogravimetry verify an improvement in thermal stability of the final PVC prepared by using a temperature trajectory during vinyl chloride monomer suspension polymerization. J. VINYL ADDIT. TECHNOL., 23:259–266, 2017. © 2015 Society of Plastics Engineers 相似文献
104.
Extended Elementary Siphons and Their Application to Liveness‐Enforcement of Generalized Petri Nets 下载免费PDF全文
Emad Abouel Nasr 《Asian journal of control》2014,16(6):1789-1810
As a significant structural object, siphons are extensively employed to implement a large number of deadlock prevention and liveness‐enforcing methods for flexible manufacturing systems modeled by Petri nets. By linear combinations, a set of elementary siphons is chosen from all strict minimal ones to be controlled and thus the structural complexity of a supervisor is greatly reduced. The concept of elementary siphons is originally proposed for ordinary Petri nets. When applied to generalized Petri nets, their selection and controllability require an additional study. In this work, the concept of augmented siphons is proposed to extend the application of the elementary ones to a class of generalized Petri nets, GLS3PR. Based on graph theory, a siphon extraction algorithm is developed to obtain all strict minimal siphons, from which augmented elementary ones are computed. In addition, the controllability conditions of dependent siphons are developed. Through fully investigating the net structure, especially weight information, the set of augmented elementary siphons is more compact and well suits for generalized Petri net models under consideration. Some examples are used to illustrate the proposed method. 相似文献
105.
Tamer Ahmed Nasr Hossam A. Abdel Fattah Adel A. R. Hanafy 《International Journal of Control, Automation and Systems》2012,10(1):11-19
Multiple-Model Adaptive Control (MMAC) is usually considered suitable for Interval Plants. This paper proposes a multiple
model adaptive controller for first order interval plant with large delays. The number of models to be used is investigated
and the controller parameters tuning is studied. The proposed scheme is applied to a numerical example for illustration. Simulation
results show the applicability of the method. 相似文献
106.
Guillaume Bécan Mathieu Acher Benoit Baudry Sana Ben Nasr 《Empirical Software Engineering》2016,21(4):1794-1841
Feature Models (FMs) are a popular formalism for modeling and reasoning about the configurations of a software product line. As the manual construction of an FM is time-consuming and error-prone, management operations have been developed for reverse engineering, merging, slicing, or refactoring FMs from a set of configurations/dependencies. Yet the synthesis of meaningless ontological relations in the FM – as defined by its feature hierarchy and feature groups – may arise and cause severe difficulties when reading, maintaining or exploiting it. Numerous synthesis techniques and tools have been proposed, but only a few consider both configuration and ontological semantics of an FM. There are also few empirical studies investigating ontological aspects when synthesizing FMs. In this article, we define a generic, ontologic-aware synthesis procedure that computes the likely siblings or parent candidates for a given feature. We develop six heuristics for clustering and weighting the logical, syntactical and semantical relationships between feature names. We then perform an empirical evaluation on hundreds of FMs, coming from the SPLOT repository and Wikipedia. We provide evidence that a fully automated synthesis (i.e., without any user intervention) is likely to produce FMs far from the ground truths. As the role of the user is crucial, we empirically analyze the strengths and weaknesses of heuristics for computing ranking lists and different kinds of clusters. We show that a hybrid approach mixing logical and ontological techniques outperforms state-of-the-art solutions. We believe our approach, environment, and empirical results support researchers and practitioners working on reverse engineering and management of FMs. 相似文献
107.
Lim Heuiseok Hooshyar Danial Ji Hyesung Lee Seolhwa Jo Jaechoon 《Wireless Personal Communications》2019,105(2):461-473
Wireless Personal Communications - The adaption of user interface (UI) promises to greatly enhance user experience (UX). This is more evident when we focus on elderly people. However, to date there... 相似文献
108.
Alavi Nezhad Khalil Abad Seyed Vahid Yilmaz Murat Jahed Armaghani Danial Tugrul Atiye 《Neural computing & applications》2018,29(2):423-433
Neural Computing and Applications - The durability of aggregates is an important factor that is used as an input parameter in desirable engineering properties along with resistance to exposure... 相似文献
109.
Nasr addin Ahmed Salem Al-Maweri Aznul Qalid Md Sabri Ali Mohammed Mansoor Unaizah Hanum Obaidellah Erma Rahayu Mohd Faizal Joan Lai P C 《Multimedia Tools and Applications》2017,76(15):16239-16261
As the advent of the Unmanned Aerial Vehicles (UAVs) has been increased, the protection of the information within the transmitted or stored video has become a big challenge. Most known drone systems attach metadata of the recorded video in separate files or in the header of the video. Current techniques make the metadata unsecure and easy to get lost and removed as well as it occupies more storage and bandwidth. In this paper, an efficient method is proposed to hide the metadata of UAVs video using the technology of digital watermarking. Discrete Wavelet Transform (DWT) is used to implement the embedding of the information robustly. The middle frequencies coefficients reside on CH3 sub-band are utilized to hide the watermark bits. In addition, a new scrambling algorithm is proposed to secure the information before hiding. The adaption of the proposed video watermarking algorithm to hide the metadata of the UAV video is achieved. The experimental results prove the high performance of the proposed method. The method had unnoticeable impact on the video quality where the PSNR of 44 dB is attained. The experiments show that the method achieves high robustness under various attacks and provides enough capacity for metadata hiding of UAV video. 相似文献
110.
Packed columns are widely used in the chemical process industries. The optimum operation of these columns requires an even distribution of gas and liquid flows. This paper describes a method for modeling the flow pattern which develops above the gas inlet system using a computational fluid dynamics (CFD) approach. The uniformity of the gas flow through the packing is assessed by means of a maldistribution factor, MF. Several factors which affect gas distribution, such as gas inlet type, gas inlet diameter and the distance between gas inlet and column bottom, were analyzed. It was found that gas distribution is more uniform as the inlet diameter and bottom distance are increased. Comparison of experimental data with a CFD simulation for several types of gas inlets, such as straight, slope and bend inlets, shows good agreement. 相似文献