Energy efficient mechanism using flexible medium access control protocol for hybrid wireless sensor networks

Energy efficiency is a primary consideration in a wireless sensor network (WSN). This is also a major parameter when designing a medium access control (MAC) protocol for WSNs. Hierarchical clustering structure is regarded suitable for WSNs due to its good performance in energy conservation. In this work, an adequately flexible mechanism for clustering WSNs is designed, in which some creative or promotional metrics are utilized, such as cluster head selection algorithm, cluster optional reconstruction, interested data transmission, multiple path routing protocol. All these strategies were cooperated to maximize energy saving of whole system. An appropriate MAC protocol for this mechanism is proposed, by flexibly switching the status of diverse sensor nodes in different strategies. The simulation results show that the proposed MAC protocol is suitable for clustering WSNs and performs well in aspects of energy efficiency, flexibility and scalability.

心理控制源与师范生心理健康相关研究

以师范生作为被试，考察其心理健康状况的年级、性别、系科、生源、经济状况、学习成绩等特征，探索了心理控制源对其心理健康的影响。结果表明：运气控制与躯体化、强迫症状、人际关系敏感、忧郁、恐怖、偏执、精神病性的偏相关显著，行为控制与躯体化、恐怖偏相关显著，控制有能感与强迫症状的偏相关显著，控制无能感与所有因子的偏相关显著，社会政治控制与所有因子的偏相关不显著。