Zhaohui Zhang^*,1,2,3, Jian Chen¹, Ligong Chen¹, Qiuwen Liu¹, Lijun Yang¹, Pengwei Wang^1,2,3, Yongjun Zheng⁴

CMC-Computers, Materials & Continua, Vol.60, No.1, pp. 117-132, 2019, DOI:10.32604/cmc.2019.05325

Abstract Recently, there are some online quantile algorithms that work on how to analyze the order statistics about the high-volume and high-velocity data stream, but the drawback of these algorithms is not scalable because they take the GK algorithm as the subroutine, which is not known to be mergeable. Another drawback is that they can’t maintain the correctness, which means the error will increase during the process of the window sliding. In this paper, we use a novel data structure to store the sketch that maintains the order statistics over sliding windows. Therefore three algorithms have… More >

Lili He^1,2, Hongtao Bai^1,2, Dantong Ouyang^1,2, Changshuai Wang^1,2, Chong Wang^1,2,3, Yu Jiang^1,2,*

CMC-Computers, Materials & Continua, Vol.60, No.2, pp. 599-613, 2019, DOI:10.32604/cmc.2019.05928

Abstract Cloud-derived wind refers to the wind field data product reversely derived through satellite remote sensing cloud images. Satellite cloud-derived wind inversion has the characteristics of large scale, computationally intensive and long time. The most widely used cloud-derived serial--tracer cloud tracking method is the maximum cross-correlation coefficient (MCC) method. In order to overcome the efficiency bottleneck of the cloud-derived serial MCC algorithm, we proposed a parallel cloud-derived wind inversion algorithm based on GPU framework in this paper, according to the characteristics of independence between each wind vector calculation. In this algorithm, each iteration is considered as… More >

Lan Sun¹, Chen Ge¹, Xin Huang¹, Yingjie Wu^1,*, Yan Gao²

CMC-Computers, Materials & Continua, Vol.58, No.1, pp. 61-78, 2019, DOI:10.32604/cmc.2019.03744

Abstract Continuous response of range query on steaming data provides useful information for many practical applications as well as the risk of privacy disclosure. The existing research on differential privacy streaming data publication mostly pay close attention to boosting query accuracy, but pay less attention to query efficiency, and ignore the effect of timeliness on data weight. In this paper, we propose an effective algorithm of differential privacy streaming data publication under exponential decay mode. Firstly, by introducing the Fenwick tree to divide and reorganize data items in the stream, we achieve a constant time complexity… More >

Ruiguo Yu^1,2, Zhiqiang Liu^1,2, Jianrong Wang^1,3, Mankun Zhao^1,2, Jie Gao^1,3, Mei Yu^1,3,*

Computer Systems Science and Engineering, Vol.33, No.4, pp. 267-274, 2018, DOI:10.32604/csse.2018.33.267

Abstract The spatio-temporal feature with historical wind power information and spatial information can effectively improve the accuracy of wind power prediction, but the role of the spatio-temporal feature has not yet been fully discovered. This paper investigates the variance of the spatio-temporal feature. Based on this, a hybrid machine learning method for wind power prediction is designed. First, the training set is divided into several groups according to the variance of the input pattern, and then each group is used to train one or more predictors respectively. Multiple machine learning methods, such as the support vector More >

Haijian Shao^{1, 2}, Xing Deng^{1, 2, *}

CMES-Computer Modeling in Engineering & Sciences, Vol.114, No.3, pp. 277-293, 2018, DOI:10.3970/cmes.2018.114.277

Abstract High accurary in wind speed forcasting remains hard to achieve due to wind’s random distribution nature and its seasonal characteristics. Randomness, intermittent and nonstationary usually cause the portion problem of the wind speed forecasting. Seasonal characteristics of wind speed means that its feature distribution is inconsistent. This typically results that the persistence of excitation for modeling can not be guaranteed, and may severely reduce the possibilities of high precise forecasting model. In this paper, we proposed two effective solutions to solve the problems caused by the randomness and seasonal characteristics of the wind speed. (1)… More >

A. Joshuva¹, V. Sugumaran²

Structural Durability & Health Monitoring, Vol.11, No.1, pp. 69-90, 2017, DOI:10.3970/sdhm.2017.012.069

Abstract Renewable energy sources are considered much in energy fields because of the contemporary energy calamities. Among the important alternatives being considered, wind energy is a durable competitor because of its dependability due to the development of the innovations, comparative cost effectiveness and great framework. To yield wind energy more proficiently, the structure of wind turbines has turned out to be substantially bigger, creating conservation and renovation works troublesome. Due to various ecological conditions, wind turbine blades are subjected to vibration and it leads to failure. If the failure is not diagnosed early, it will lead… More >

Liu Duo-Neng^1,2, Hou Zhong-Xi¹, Guo Zheng¹, Yang Xi-Xiang¹, Gao Xian-Zhong¹

CMES-Computer Modeling in Engineering & Sciences, Vol.111, No.6, pp. 531-565, 2016, DOI:10.3970/cmes.2016.111.531 - 01 March 2022

Abstract Dynamic soaring is a flight maneuver to exploit gradient wind field to extend endurance and traveling distance. Optimal trajectories for permissible wind conditions are generated for loitering dynamic soaring as well as for traveling patterns with a small unmanned aerial vehicle. The efficient direct collection approach based on the Runge-Kutta integrator is used to solve the optimization problem. The fast convergence of the optimization process leads to the potential for real-time applications. Based on the results of trajectory optimizations, the general permissible wind conditions which involve the allowable power law exponents and feasible reference wind… More >

B. J. Zhu^1,2, Z. X. Hou¹, Y. F. Lu¹, S. Q. Shan¹

CMES-Computer Modeling in Engineering & Sciences, Vol.105, No.6, pp. 467-490, 2015, DOI:10.3970/cmes.2015.105.467

Abstract This paper mainly analyzes the dynamic soaring of UAV utilizing gradient wind. Dynamic soaring is an efficient path in which UAV absorbs energy from environment to enhance its flight endurance. A set of three-dimensional point dynamic equations for a soaring aircraft in three degrees of freedom is used in calculations. To simplify the calculation, the gradient wind’s direction is taken into decomposition. The notion of trajectory subsection analysis is applied to account for the energy transformation mechanism during the dynamic soaring, and the zone of direction is converted into cutting-in angle, which is regarded as More >

G. Frulla¹, P. Gili¹, M. Visone², V. D’Oriano^2,3, M. Lappa⁴

FDMP-Fluid Dynamics & Materials Processing, Vol.11, No.3, pp. 257-277, 2015, DOI:10.3970/fdmp.2015.011.257

Abstract A practical engineering approach to the design of a 60 kW wind generator with improved performances is presented. The proposed approach relies on the use of a specific, "ad hoc'' developed software, OPTIWR (Optimization Software), expressly conceived to define an "optimum'' rotor configuration in the framework of the blade-element-momentum theory. Starting from an initial input geometric configuration (corresponding to an already existing 50 kW turbine) and for given values of the wind velocity V_wind and of the advance ratio X = V_wind/ΩR (where Ω is the blade rotational speed and R is the propeller radius), this software… More >

M. Kriraa^1,2, M.EL Alami¹, M. Abouricha¹

FDMP-Fluid Dynamics & Materials Processing, Vol.10, No.4, pp. 443-464, 2014, DOI:10.3970/fdmp.2014.010.443

Abstract Natural Convection in a vertical channel with internal objects is encountered in several technological applications, among them particular interest of heat dissipation from electronic circuits, refrigerators, heat exchangers, nuclear reactors fuel elements, dry cooling towers, home ventilation, etc. This numerical study deals with the study of natural convection in a vertical convergent channel with a circular block. The considered parameters are 10⁴ ≤ Ra ≤ 10⁶, Prandtl number Pr = 0.71, channel height 10 ≤ A ≤ 30, inclination angle of the channel φ = 0,2.86°,5.74°. The size block conductivity and the block radius are assumed to be More >