面向互联互通的电力营商数据增量式更新与共享算法

在电力营商数据增量式更新过程中,由于数据之间存在强相关性,导致更新算法需要消耗的时间成本较高,在具体操作上实用性需要进一步提高。为了解决这一问题,提出面向互联互通的电力营商数据增量式更新与共享算法。利用数据之间的强关联性,挖掘其中的正相关性和负相关性,确定关联规则。在此基础上,计算数据间的支持度和置信度,筛选出符合要求的数据并扫描数据库完成数据增量式更新。针对不同类型的数据,设计共享数据库,并建立时态模型,实现数据的实时共享。实验结果表明,本研究提出的电力营商数据增量式更新与共享算法运行时间快,内存节省比例高,整体实用性得到了提高。

Wavelet neural network aerodynamic modeling from flight data based on pso algorithm with information sharing and velocity disturbance

For the accurate description of aerodynamic characteristics for aircraft,a wavelet neural network (WNN) aerodynamic modeling method from flight data,based on improved particle swarm optimization (PSO) algorithm with information sharing strategy and velocity disturbance operator,is proposed.In improved PSO algorithm,an information sharing strategy is used to avoid the premature convergence as much as possible;the velocity disturbance operator is adopted to jump out of this position once falling into the premature convergence.Simulations on lateral and longitudinal aerodynamic modeling for ATTAS (advanced technologies testing aircraft system) indicate that the proposed method can achieve the accuracy improvement of an order of magnitude compared with SPSO-WNN,and can converge to a satisfactory precision by only 60 120 iterations in contrast to SPSO-WNN with 6 times precocities in 200 times repetitive experiments using Morlet and Mexican hat wavelet functions.Furthermore,it is proved that the proposed method is feasible and effective for aerodynamic modeling from flight data.

A Practical Group Key Management Algorithm for Cloud Data Sharing with Dynamic Group

Cloud data sharing service, which allows a group of people to work together to access and modify the shared data, is one of the most popular and efficient working styles in the enterprises. However, the cloud server is not completely trusted, and its security could be compromised by monetary reasons or caused by hacking and hardware errors. Therefore, despite of having advantages of scalability and flexibility, cloud storage service comes with privacy and the security concerns. A straightforward method to protect the user's privacy is to encrypt the data stored at the cloud. To enable the authenticated users to access the encrypted cloud data, a practical group key management algorithm for the cloud data sharing application is highly desired. The existing group key management mechanisms presume that the server is trusted. But, the cloud data service mode does not always meet this condition. How to manage the group keys to support the scenario of the cloud storage with a semi-trusted cloud server is still a challenging task. Moreover, the cloud storage system is a large-scale and open application, in which the user group is dynamic. To address this problem, we propose a practical group key management algorithm based on a proxy re-encryption mechanism in this paper. We use the cloud server to act as a proxy tore-encrypt the group key to allow authorized users to decrypt and get the group key by their private key. To achieve the hierarchical access control policy, our scheme enables the cloud server to convert the encrypted group key of the lower group to the upper group. The numerical analysis and experimental results further validate the high efficiency and security of the proposed scheme.