this work explains and describes the evolution of ATS (Air Traffic Services) messaging including the background, standards and constraints which ICAO (international Civil Aviation Organization) is working within and t...
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the Unified Modelling Language (UML) is a well-known family of notations for software modelling. Recently, a new version of UML has been released. In this paper we examine the Activity Diagrams notation of this latest...
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A wireless sensor network (WSN) typically consists of a large number of small sensor nodes and one or more high-end control and data aggregation nodes. Sensor nodes have limited computation and communication capabilit...
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A wireless sensor network (WSN) typically consists of a large number of small sensor nodes and one or more high-end control and data aggregation nodes. Sensor nodes have limited computation and communication capabilities, and communicate via wireless links. Consequently, WSNs are highly vulnerable to attacks. this vulnerability is exacerbated when WSNs have to operate unattended in a hostile environment, such as battlefields. In this paper, we propose a novel self-organizing key management scheme for large-scale WSNs, called Sunivable and efficient clustered keying (SECK). Our scheme was designed specifically to address the key management issues within the low-tier of a hierarchical network architecture. Previous approaches for WSN key management adequately addressed operational issues, but to a large extent, ignored robustness and recoverability issues. Using simulation and analysis, we show that SECK is highly robust against key and node captures, and has noteworthy advantages over other key management schemes.
this paper presents a new channel allocation scheme with preemptive priority for the integrated voice/data mobile network. Based on the scheme, a two-dimensional Markov process is built, and the steady-state probabili...
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ISBN:
(纸本)10972641
this paper presents a new channel allocation scheme with preemptive priority for the integrated voice/data mobile network. Based on the scheme, a two-dimensional Markov process is built, and the steady-state probability is solved by the matrix-analytic method. the preemptive priority mechanism introduced gives more benefit to voice traffic at the expense of degrading some data traffic, while the victim buffer compensates the degradation and has no negative effect on voice traffic. From the analysis and numerical results, we can conclude that our scheme can guarantee different QoS requirements from different traffic classes, and significantly improve the channel utilization.
As its name indicates, NGSCB aims to be the "Next-Generation Secure Computing Base". As envisioned in the context of Trusted Computing initiatives, NGSCB provides protection against software attacks. this pa...
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ISBN:
(纸本)3540232524
As its name indicates, NGSCB aims to be the "Next-Generation Secure Computing Base". As envisioned in the context of Trusted Computing initiatives, NGSCB provides protection against software attacks. this paper describes NGSCB using a logic for authentication and access control. Its goal is to document and explain the principals and primary APIs employed in NGSCB.
this paper deals with distributed control problems by means of distributed games played on Mazurkiewicz traces. the main difference with other notions of distributed games recently introduced is that, instead of havin...
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ISBN:
(纸本)3540240586
this paper deals with distributed control problems by means of distributed games played on Mazurkiewicz traces. the main difference with other notions of distributed games recently introduced is that, instead of having a local view, strategies and controllers are able to use a more accurate memory, based on their causal view. Our main result states that using the causal view makes the control synthesis problem decidable for series-parallel systems for all recognizable winning conditions on finite behaviors, while this problem with local view was proved undecidable even for reachability conditions.
In this paper, we propose a new MAC protocol, named Q-PCF (quality-of-service PCF), which provides QoS guarantees to real-time multimedia applications for WLANs. Specifically, Q-PCF has the following attractive featur...
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In this paper, we propose a new MAC protocol, named Q-PCF (quality-of-service PCF), which provides QoS guarantees to real-time multimedia applications for WLANs. Specifically, Q-PCF has the following attractive features. First, it supports multiple priority levels and guarantees that high-priority stations always join the polling list earlier than low-priority stations. Second, it provides fast reservation scheme such that real-time stations can get on the polling list in bounded time. third, it employs dynamic bandwidth allocation scheme to support CBR/VBR transportation and provide per-flow probabilistic performance assurances. Forth, it adopts the novel mobile-assisted admission control technique such that the access point can admit as many newly flows as possible, while not violating admitted flows' guarantees. Simulation results do confirm that Q-PCF achieves high goodput and low frame delay dropped rate. Last but not least, we believe that the Q-PCF protocol can be easily applied to the current IEEE 802.11 products without major modifications.
Current search techniques over unstructured peer-to-peer networks rely on intelligent forwarding-based techniques to propagate queries to other peers in the network. Forwarding techniques are attractive because they t...
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Current search techniques over unstructured peer-to-peer networks rely on intelligent forwarding-based techniques to propagate queries to other peers in the network. Forwarding techniques are attractive because they typically require little state and offer robustness to peer failures; however they have inherent performance drawbacks due to the overhead of forwarding and lack of central control. We study GUESS, a nonforwarding search mechanism, as a viable alternative to currently popular forwarding-based mechanisms. We show how non-forwarding mechanisms can be over an order of magnitude more efficient than forwarding mechanisms; however, they must be deployed with care, as a naive implementation can result in highly suboptimal performance, and make them susceptible to hotspots and misbehaving peers.
Traditionally, interaction methods for wearable computers have focused on input to the computer itself, yet little has been done when it comes to allowing interaction withthe surrounding environment. Pervasive comput...
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Traditionally, interaction methods for wearable computers have focused on input to the computer itself, yet little has been done when it comes to allowing interaction withthe surrounding environment. Pervasive computing, on the other hand, offers access to computational power from any place all the time, yet most interaction techniques utilize either physical hardware or monitoring of the user in order to receive input. this paper presents a novel form of interaction by which a wearable computer user can interact with and control a pervasive computing environment in a natural and intuitive manner. Using sensors, the user can be allowed to literally "throw" events into the environment as a way of interacting with devices and computers.
Real-time group editors allow distributed users to work on local replicas of a shared document simultaneously to achieve high responsiveness and free interaction. Operational transformation (OT) is the standard method...
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Real-time group editors allow distributed users to work on local replicas of a shared document simultaneously to achieve high responsiveness and free interaction. Operational transformation (OT) is the standard method for consistency maintenance in state-of-the-art group editors. It is potentially able to achieve content consistency (convergence) as well as intention consistency (so that the converged content is what the users intend), while traditional concurrency control methods such as locking and serialization often cannot. However, existing OT algorithms are often not able to really guarantee consistency due to important algorithmic flaws that have been there for fourteen years. We present a novel state difference based transformation (SDT) algorithm to solve the problem. Our result also reveals that the standard priority schemes to break ties in distributed systems should be used with more caution.
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