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In many sensor network applications the major traffic pattern consists of data collected from many source nodes to a sink through a tree. In this paper, we propose S-Non Bcn based on nonbeacon-enabled (Non Bcn) mode of IEEE 802.15.4, an energy-efficient and low-collision MAC that is designed and optimized for such data gathering trees in wireless sensor networks. S-Non Bcn uses staggered sleep mechanism...
Simulating passenger flows within airports is very important as it can provide an indication of queue lengths, bottlenecks, system capacity and overall level of service. To date, visual simulation tools such as agent-based models have focused on processing formalities such as check-in, and not incorporate discretionary activities such as duty-free shopping. As airport retail contributes greatly to...
In recent studies, an equal-spacing-based (equal-SP) design was developed to generalize and enhance the reference design in IEEE 802.11e standard. Different from the reference design in which all streams will be scheduled in a common minimum spacing, the equal-SP design may schedule different streams with different spacings and it might improve bandwidth utilization of the reference design, up to...
The ability to conduct advance reservations within grid environments is crucial for applications that want to utilize distributed resources in a predictable and efficient way. Advance reservations are essential for supporting deadline driven applications and the co-allocation of distributed resources. Further, advance reservations can significantly enhance the capabilities of resource brokers. Many...
This paper studies the performance of Voice-over-Internet-Protocol (VoIP) service in the third generation (3G) long-term evolution (LTE)-Advanced relaying networks. We propose a semi-persistent scheduling algorithm for the VoIP service in the LTE-Advanced relaying networks. The performance of the presented algorithm is verified by system-level simulation. Deployments with different number of relay...
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...
Communication scheduling is a crucial cause of interfering networked control stability. For data communication network triggered by event, time delay and packet dropout induced by scheduling policy is analyzed; quadratic performance criterion is computed under various timing conditions based on Continuous linear-quadratic-Gaussian theory; data packet is dropped voluntarily in collision of sending...
In this paper, we present a stateless multi-server guaranteed rate scheduling service model that utilizes multiple, asymmetric wireless channels to maximize service guarantees for in-elastic flows. One of the major consequences of multichannel flow forwarding is the increased intra-path and inter-path end-to-end delay variations between successive packets of a stream. These variations cause problems...
This paper studies data forwarding in wireless sensor networks (WSNs) where sensor nodes are randomly duty-cycled to save energy. The duty-cycling operation requires the data delivery strategy to be more adaptive for the dynamics caused by the uncertainty of node working schedules. However, the existing maximum-advance routing scheme, at each step the forwarding node selects the node closest to the...
There are much collaboration and cooperation in the dynamic, multi-institutional virtual grid. Grid provides a good bridge between the resource users and the resource providers. Especially in the agent-based grid system, agents could provide services for the scheduling of applications that make grid resources better use. We have proposed a resource discovery mechanism with negotiation in grid environment...
Medium access control (MAC) protocols play a crucial role in energy-efficiency, latency reduction for sensor networks. Many research efforts have been made to reduce energy consumption and shorten delay in multi-hop WSNs. Although some existing MAC protocols are energy-efficient and are able to mitigate the end-to-end delivery latency, there are great potential for further improvements. In this paper,...
In mobile and wireless networks, data broadcasting for popular data items enables the efficient utilization of the limited wireless bandwidth. However, efficient data scheduling schemes are needed to fully exploit the benefits of data broadcasting. This motivated the proposal of several broadcast scheduling policies, which have mostly focused on either minimizing response time, or drop rate when requests...
The research in the aspect of flight delay and delay propagation is relatively short in domestic. A flight-delay and delay propagation model is established based on Bayesian network (BN). After trained the network by real data with Expectation-Maximization (EM) arithmetic, the influences from the Arrival-delay and the Flight-cancellation on the departure-delay are analyzed under different all kinds...
IEEE 802.16, a standard for wireless MAN broadband access technology, provides a flexible QoS mechanism in MAC layer for wild variety classes of services. However, it fails to define specific admission control strategy and scheduling algorithm, therefore, those aspects about QoS guarantee mechanisms are becoming the research hotspot in recent years. In this paper, focusing on the features of services...
In recent years, flight delay problem blocks the development of the civil aviation industry all over the world. And delay propagation always is a main factor that impacts the flight's delay. All kinds of delays often happen in nearly-saturated or overloaded airports. This paper we take one busy hub-airport as the main research object to estimate the arrival delay in this airport, and to discuss the...
IEEE802.16, as a wireless MAN broadband access standard, defines a flexible QoS mechanism in MAC layer for wild variety classes of services. However, it dose not define specific admission control strategy and scheduling algorithm, which are becoming the research hotspot in recent years. In this paper, we focus on the features of services defined in IEEE802.16, including UGS, ertPS, rtPS, nrtPS and...
Railway scheduling has been a significant issue in the railway industry. Over the last few years, numerous approaches and tools have been developed to compute railway scheduling. However, robust solutions are necessary to absorb short disruptions. In this paper, we present the robustness problem from the point of view of railway operators and we give some guidelines to measure robustness in timetabling...
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