The designation of the cluster number K and the initial centroids is essential for K-modes clustering algorithm. However, most of the improved methods based on K-modes specify the K value manually and generate the ini...The designation of the cluster number K and the initial centroids is essential for K-modes clustering algorithm. However, most of the improved methods based on K-modes specify the K value manually and generate the initial centroids randomly, which makes the clustering algorithm significantly dependent on human-based decisions and unstable on the iteration time. To overcome this limitation, we propose a cohesive K-modes (CK-modes) algorithm to generate the cluster number K and the initial centroids automatically. Explicitly, we construct a labeled property graph based on index-free adjacency to capture both global and local cohesion of the node in the sample of the input datasets. The cohesive node calculated based on the property similarity is exploited to split the graph to a K-node tree that determines the K value, and then the initial centroids are selected from the split subtrees. Since the property graph construction and the cohesion calculation are only performed once, they account for a small amount of execution time of the clustering operation with multiple iterations, but significantly accelerate the clustering convergence. Experimental validation in both real-world and synthetic datasets shows that the CK-modes algorithm outperforms the state-of-the-art algorithms.展开更多
针对广泛应用于水声通信网的MACAW(medium access with collision auoidance for wireless)协议在多跳通信延时严重的问题,在传统握手协议的基础上,提出了节点预约的方法.该方法通过多跳转发的握手信号CTS预约处于通信链路上的下级节点...针对广泛应用于水声通信网的MACAW(medium access with collision auoidance for wireless)协议在多跳通信延时严重的问题,在传统握手协议的基础上,提出了节点预约的方法.该方法通过多跳转发的握手信号CTS预约处于通信链路上的下级节点,并通过复用上级节点的握手信号CTS(clear to send)及数据信号DATA,形成一种流水线式的传输协议.仿真结果表明:在多跳网络通信中,该协议与传统的MACAW相比,在能耗变化较小的情况下,时延性能有较大幅度的提高,适用于移动节点通信、灾难预警、战时侦测等需要快速反应的水声通信应用场景.展开更多
基金supported by the National Natural Science Foundation of China under Grant No. 61772534the Excellent Chinese-Foreign Youth Exchange Foundation Program of Chinese Association of Science and Technology under Grant No. 311319000207.
文摘The designation of the cluster number K and the initial centroids is essential for K-modes clustering algorithm. However, most of the improved methods based on K-modes specify the K value manually and generate the initial centroids randomly, which makes the clustering algorithm significantly dependent on human-based decisions and unstable on the iteration time. To overcome this limitation, we propose a cohesive K-modes (CK-modes) algorithm to generate the cluster number K and the initial centroids automatically. Explicitly, we construct a labeled property graph based on index-free adjacency to capture both global and local cohesion of the node in the sample of the input datasets. The cohesive node calculated based on the property similarity is exploited to split the graph to a K-node tree that determines the K value, and then the initial centroids are selected from the split subtrees. Since the property graph construction and the cohesion calculation are only performed once, they account for a small amount of execution time of the clustering operation with multiple iterations, but significantly accelerate the clustering convergence. Experimental validation in both real-world and synthetic datasets shows that the CK-modes algorithm outperforms the state-of-the-art algorithms.
文摘针对广泛应用于水声通信网的MACAW(medium access with collision auoidance for wireless)协议在多跳通信延时严重的问题,在传统握手协议的基础上,提出了节点预约的方法.该方法通过多跳转发的握手信号CTS预约处于通信链路上的下级节点,并通过复用上级节点的握手信号CTS(clear to send)及数据信号DATA,形成一种流水线式的传输协议.仿真结果表明:在多跳网络通信中,该协议与传统的MACAW相比,在能耗变化较小的情况下,时延性能有较大幅度的提高,适用于移动节点通信、灾难预警、战时侦测等需要快速反应的水声通信应用场景.
