Yongchang Ma

It has been proved radio sleep can significantly prolong the lifetime of wireless sensor networks; however, sleep causes more multi-hop latency and fewer throughputs under heavy load. This paper proposes a dynamic sleep MAC protocol LD3-MAC for wireless sensor networks, which uses global schedule, stagger sleep and periodic synchronization to achieve sleep coordination. The dynamic listening scheme that employs limited

Given the anticipated increases in highway traffic, the scale and complexity of the traffic infrastructure will continue to grow progressively in time and in distributed geographical areas. To assure transportation efficiency, safety, and security in the presence of such growth, it is critical to identify an infrastructure development methodology that can adapt to expansions while assuring reliable operation for both centralized monitoring and distributed management. In this paper, a wireless sensor network design methodology is presented, aimed at providing effective distributed surveillance, anomaly detection, and coordinated response. The proposed methodology integrates state-of-the-art traffic sensors, with flexibly programmable controller devices that can integrate with the available traffic control equipments. The system methodology provides a paradigm in which sensors and controllers can be progressively incorporated and programmed to autonomously coordinate with peer sensors and a hierarchy of controllers to detect, notify, and react to anomalous events. Since the system can tolerate failure of parts of the system, as the network connectivity continues to increase, the proposed sensor network will have positive implications on evacuation plans during natural disasters or terrorist attacks. To illustrate the design methodology and usage, a simulated system along a freeway corridor in South Carolina was constructed in an integrated microscopic traffic and wireless sensor network simulation platform, in which distributed incident detection and response functions were implemented. The test results, including detection and false alarm rates and wireless communication latencies, are analyzed to identify insights of the system's operation and potential enhancement strategies.

Limited specific evidence is available on the effectiveness of using contraflow as an evacuation traffic management tool. This study was conducted to determine the best combination of strategy options for evacuating Charleston, SC, along route I-26 during the event of a hurricane or other events. PARAMICS microscopic traffic simulator was used to evaluate the impact of each combination of evacuee response timing and traffic control strategy, such as contraflow, with respect to average vehicular travel time and evacuation duration. Analysis revealed the combination of management strategies that created the lowest evacuation durations and travel times for several types of anticipated evacuee responses. Furthermore, a proposed reconfiguration of the I-526/I-26 interchange for contraflow operations produced additional savings in travel times and evacuation durations. These findings support the use of all lanes for contraflow during all evacuations and provide justification to examine a possible reconfiguration of the I-526/I-26 interchange for use during evacuations.

... As FIGURE 1 Concept of SVR. Kernel x1,y1 x2,y2 . . . . SVR TRAINING Training samples from y = f (x) ... The training time of the SVR model was <2 s in all the training cycles. For CBR, a new case must be matched with all the stored cases to retrieve the closely matching cases. ...

... View larger version(18K), Figure 1 Topology of centralized and distributed communication network ... integrated simulator architecture is illustrated in Figure 2. To initiate a simulation, in PARAMICS ... Figure 3 shows the execution flowchart of the interactive process of PARAMICS and ...

Understanding work zone traffic behavior is important for the planning and operation of work zones. The objective of this paper is to develop a mathematical model of work zone traffic flow elements by analyzing the relationships between speed, flow, and density that can be used to estimate the capacity of work zones. Traffic flow data were collected from 22 work

This paper presents a framework for real-time highway traffic condition assessment using vehicle kinetic information, which is likely to be made available from vehicle-infrastructure integration (VII) systems, in which vehicle and infrastructure agents communicate to improve mobility and safety. In the proposed VII framework, the vehicle onboard equipment and roadside units (RSUs) collaboratively work, supported by an artificial intelligence (AI)