International Journal of Intelligent Engineering and Systems

7

Authors: Yan Liu ,Kai Liu , Wei-liang Tao, Ye Zhu

Compared to other methods, insulator’s contact angles detection can obtain more precise and more accurate hydrophobicity in parts of insulator, getting in-depth information like hydrophobicity of shed material, migration of the hydrophobicity after polluted insulator, attenuation and recovery characteristics of the insulation performance under certain conditions, all of which are its particular advantages. A new detection method of insulator’s performance is proposed in this paper with measuring contact angles. With this method, the boundary curve of water drop on insulator’s surface was extracted with image processing, then the polynomial fitting was deployed to fit the boundary curve, and contact angles of water drop were calculated by differentiate the polynomial deduced from the polynomial fitting. So the performance of the insulator can be detected and the process doesn’t need manual intervention which makes the detect result accurate and objective. Experiments show that the root mean square error of the measurement is below 2%.

8

Authors: Yan Liu, Wei Liangtao, Kai Liu, Ying Xu

Recently, several data storage schemes have been developed to store massive sensor data in the wireless sensor networks (WSNs). A crucial task of WSNs is to disseminate useful information to users efficiently and handle the data storage architecture incorporating their extreme resource constraints. A Distributed Index based Multi-resolution Storage Architecture (DIMSA) for data storage and retrieval at multiple levels of detail in WSNs is proposed in this paper. The proposed scheme could automatically disseminate useful information to users in correspondence to the user defined level of detail to save energy. In the condition that some attributes are included in many events, the values for these attributes have to be replicated and stored at different places in the network for each individual event in traditional data-centric storage schemes. This will consume some extra energy. To address this problem, DIMSA deploys an attribute allocation scheme for finding a good distribution of attributes to the sensor networks. In addition, a distributed index scheme is also proposed to avoid query flooding and extra data transmission. Analysis and simulations are conducted to evaluate the performance of the proposed scheme. The results show that DIMSA outperforms the traditional data-centric storage scheme like GHT.