The paper proposes a throughput and energy-aware medium-access-control protocol for wireless sensor networks. The proposed approach provides a sleeping-time adjustment scheme to flexibly adjust the sleep time to reduc...
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The paper proposes a throughput and energy-aware medium-access-control protocol for wireless sensor networks. The proposed approach provides a sleeping-time adjustment scheme to flexibly adjust the sleep time to reduce the wasted energy in a low-traffic network and increase the throughput in a high-traffic network. The sleeping and waking durations are determined using time counters rather than time slots. A waking-time sharing scheme is responsible for establishing the common waking time among a group of neighbors for group communication. The proposed protocol solves the energy inefficiency caused by idle listening. Simulation experiments have been performed to demonstrate the effectiveness of the proposed approach compared to some other energy-aware medium-access-control protocols.
As technology develops, people are using an ever broader and heterogeneous range of ICT devices and network-based services. The result is an enormous burden of complexity on the shoulders of users, service providers a...
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As technology develops, people are using an ever broader and heterogeneous range of ICT devices and network-based services. The result is an enormous burden of complexity on the shoulders of users, service providers and network operators. The goal of the Simplicity project, supported by the European Union, is to reduce this complexity by: (i) providing automatic customization of user access to services and the network; (ii) automatically adapting services to terminal characteristics and user preferences; (iii) orchestrating network capabilities. The Simplicity approach is based on a personalization device, the so-called Simplicity device, which, together with a brokerage framework, offers transparent service configuration and runtime adaptation, according to user preferences and computing/networking context conditions. This paper presents the Simplicity project, briefly discusses its architecture and introduces the Simplicity demonstrator: a proof of concept implementation used to verify our approach, through diverse usage scenarios. In addition, we introduce the main aspects of a follow-up project of Simplicity, named SMS.
作者：
Erlebach, ThomasFiala, JiříETH Zürich
Computer Engineering and Networks Lab. CH-8092 Zürich Switzerland Charles University
Department of Applied Mathematics Institute for Theoretical Computer Science Malostranské nám. 2/25 118 00 Prague Czech Republic
This chapter surveys on-line and approximation algorithms for the maximum independent set and coloring problems on intersection graphs of disks. It includes a more detailed treatment of recent upper and lower bounds o...
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A new fast time synchronization technique is proposed for DVB-H receiver in this paper. Only one DVB-H OFDM symbol is needed to achieve accurate time synchronization by using the correlation function of the received s...
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A new fast time synchronization technique is proposed for DVB-H receiver in this paper. Only one DVB-H OFDM symbol is needed to achieve accurate time synchronization by using the correlation function of the received signal and four time-domain local references generated from the DVB-H scattered pilots. The computation complexity of the new algorithm is further reduced by limiting the range of correlation function, which is realized by exploiting the cyclic property of the OFDM signal
A novel optimisation technique inspired by natural ecosystems is presented, where the optimisation works at two levels: a first optimisation, migration of services which are distributed in a decentralised peer-to-peer...
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ISBN:
(纸本)9781424404636
A novel optimisation technique inspired by natural ecosystems is presented, where the optimisation works at two levels: a first optimisation, migration of services which are distributed in a decentralised peer-to-peer network, operating continuously in time; this process feeds a second optimisation based on evolutionary computing that operates locally on single peers and is aimed at finding solutions to satisfy locally relevant constraints. Through this two-fold process, the local search is accelerated and will yield better local optima, because the distributed optimisation already provides a good sampling of the search space by making use of computations already performed in other peers with similar constraints. We call this new distributed optimisation architecture a digital ecosystem, an ecosystem-orientated architecture (EOA) created by extending a service-oriented architecture (SOA) with distributed evolutionary computing (DEC). The digital ecosystem will allow services to recombine and evolve over time, constantly seeking to improve their effectiveness for the user base. individuals within our digital ecosystem will be applications (groups of services), created in response to user requests by using evolutionary optimisation to aggregate the services. These individuals will migrate through the digital ecosystem and adapt to find niches where they are useful in fulfilling other user requests
A new fast time synchronization technique is proposed for DVB-H receiver in this paper. Only one DVB-H OFDM symbol is needed to achieve accurate time synchronization by using the correlation function of the received s...
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We investigate to what extent flooding and routing is possible if the graph is allowed to change unpredictably at each time step. We study what minimal requirements are necessary so that a node may correctly flood or ...
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ISBN:
(纸本)1595930922
We investigate to what extent flooding and routing is possible if the graph is allowed to change unpredictably at each time step. We study what minimal requirements are necessary so that a node may correctly flood or route a message in a network whose links may change arbitrarily at any given point, subject to the condition that the underlying graph is connected. We look at algorithmic constraints such as limited storage, no knowledge of an upper bound on the number of nodes, and no usage of identifiers. We look at flooding as well as routing to some existing specified destination and give algorithms. Copyright 2005 ACM.
When we use multicast services it? heterogeneous networks such that the wired networks and the wireless ad hoc networks are combined, it is inefficient to apply the wired overlay multicast protocol to wireless ad hoc ...
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ISBN:
(纸本)1932415556
When we use multicast services it? heterogeneous networks such that the wired networks and the wireless ad hoc networks are combined, it is inefficient to apply the wired overlay multicast protocol to wireless ad hoc network and vice versa, due to existence of mobility and the limitation of bandwidth, power and etc. With our best knowledge, several multicast gateways have been studied in order to integrate multicast between heterogeneous networks. Existing multicast gateways need protocol translations when a node wants to join for multicast group which is in different environmental networks. However, deploying translation functions to existing gateway causes another deployment problem. In this paper, we propose two cases to place a translation function. It can be located in wireless ad hoc nodes, wired end nodes with Rendezvous Point. We discuss and compare to each case and problem occurred, and analyze using performance metrics such as control overhead, join latency and stretch The control overhead is calculated by number of control messages. The more control messages are required when the translation function is in the wireless ad hoc network. The join latency is shorter when the translation function is in the wired network. Also, the stretch is better when the wireless nodes have translation function.
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