Wireless sensor networks are often deployed in open or even hostile environment, its security problem is very prominent, Data aggregation is easily to be attacked for security during the specific implementation process. In order to reduce the transmission of redundant data and enhance security, this article proposed a secure data aggregation and authentication scheme, .data was gathered according to the mode code, collection data was transmitted in encrypted form which will be selected nodes, ensured the confidentiality of the data; A session key was generated and delaied aggregation and authentication by using counter, ensured the integrity , authenticity and freshness of data during the transmission .The security analysis showed that the program had higher security which resisted the attack initiativly, node compromise attack and select forwarding attack and other malicious behaviors.

Human error is a main factor causing the engine assembly quality defects. This paper presented the application of the Root Cause Retrospective Analysis (RCRA) of the Cognitive Reliability and Error Analysis Method (CREAM) in the engine assembly process, proposed a new model of the RCRA for engine assembly failure within the framework of HRA (Human Reliability Analysis) service system for the engine assembly. The application of the model was illustrated by an example. The research belongs to one of the core functions of HRA service system, which can be used to perform the human error analysis in the process of the engine assembly, so as to provide guidance for production.

In this paper, we propose a context-awareness based personalized recommender system in the pervasive application space. The recommender system comprises the personalized recommender engine and the distributed context management framework. With a hybrid approach, the personalized recommender engine combines those contexts into the decisions on recommendations to get more comprehensive recommendation effectiveness. In contrast with existing middleware of context-awareness, the recommender system has an ability of user-centric recommendation. At the end of this paper, an emphasis is put on the metrics of the effectiveness of the recommender system.

This paper introduces the architecture of wireless sensor networks, compares several typical routing protocols of wireless sensor network, and focuses on the research of directed diffusion(DD) protocol and geograohic and energy aware routing(GEAR) protocol. GEAR selects the next hop nodes based on the neighbor node location information, limiting the information diffused in the network in the appropriate location of region, which can effectively reduce the maintaining routing information needed for overhead, and form the energy efficient data transmission path, to achieve the purpose of extending the life cycle of the network. Related research work provides the reference for the future network construction.