zengxiao chi

Traffic flow forecasting is an important issue for route guidance and traffic flow control in intelligent transportation system. Real-time and reliable traffic flow information is directly related to the effect of traffic management and control. In this paper, considering the nonlinear characteristics of traffic flow caused by the complexity of time-varying and changing uncertainties in the actual traffic system, we use support vector machine (SVM) model to predict short-term traffic flow. Then combining the autocorrelation of traffic flow, an improved prediction model combining ARIMA and SVM is proposed. Finally, the model is validated by using the measured traffic data and R language. Simulation results show that the improved ARIMA-SVM model can enhance the accuracy of traffic flow forecasting greatly and describe the law of traffic flow exactly, and it has a wide application prospect in short-term traffic flow and other nonlinear prediction problems.

Energy consumption problem is one of the key issues in Wireless Sensor Network (WSN). Usually sensor nodes are far from one or more sink nodes. In such a case, it calls for deploying some relay nodes as the interval nodes to transmit data from sensor nodes to sink nodes. A relay node placement algorithm in two-tiered WSN model is proposed in this thesis. This algorithm first constructs an optimum spanning tree for unlimited number of relay nodes. Then, a greedy strategy was put forward to remove some relay nodes from the tree. Under the restriction that each relay node must satisfy its communication capacity limitation, the greedy strategy aims to minimize the total energy consumption to prolong the lifetime of whole network.

With the rapid development of mobile Internet technology and the widespread use of smart phones, more and more attentions have paid on network access and interactive applications through mobile phones. Android becomes the most favorite smart phone by the people and programmers because of its open-source, easy to use and biggest global market share and has broad prospects for development. This article describes the design and implementation of Android mobile operating system based group communication and navigation system. The system provides a friendly group communication platform between friends in order to timely communicate and a real-time positioning, navigation and path planning capabilities with the help of GPS.