A key problem in networks that support advance reservations is the routing and time scheduling of connections with flexible starting time. In this paper we present a multicost routing and scheduling algorithm for sele...
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A key problem in networks that support advance reservations is the routing and time scheduling of connections with flexible starting time. In this paper we present a multicost routing and scheduling algorithm for selecting the path to be followed by such a connection and the time the data should start so as to minimize the reception time at the destination, or some other QoS requirement. The utilization profiles of the network links, the link propagation delays, and the parameters of the connection to be scheduled form the inputs to the algorithm. We initially present a scheme of non-polynomial complexity to compute a set of so-called non-dominated candidate paths, from which the optimal path can be found. By appropriately pruning the set of candidate paths using path pseudo-domination relationships, we also find multicost routing and scheduling algorithms of polynomial complexity. We examine the performance of the algorithms in the special case of an Optical Burst Switched network. Our results indicate that the proposed polynomial time algorithms have performance that it is very close to that of the optimal algorithm.
We propose QoS-aware scheduling algorithms for grid networks that are capable of optimally or near-optimally assigning computation and communication tasks to grid resources. The routing and scheduling algorithms to be...
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We propose QoS-aware scheduling algorithms for grid networks that are capable of optimally or near-optimally assigning computation and communication tasks to grid resources. The routing and scheduling algorithms to be presented take as input the resource utilization profiles and the task characteristics and QoS requirements, and co-allocate resources while accounting for the dependencies between communication and computation tasks.
In this paper we introduce an equation-based smooth multicast congestion control for adaptive multimedia transmission over best-effort wired networks. Target of the proposed schema is (a) smooth transmission rate, in ...
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In this paper we introduce an equation-based smooth multicast congestion control for adaptive multimedia transmission over best-effort wired networks. Target of the proposed schema is (a) smooth transmission rate, in order to minimize the audio-video (AV) encoding and decoding distortion and (b) TCP friendly transmission. The "smoothness" lays in the way the TCP-friendly transmission rate is filtered. We integrate the congestion control functions in the RTP protocol and use the RTCP sender and receiver reports to provide the necessary feedback information for the sender's adaptive transmission rate. The performance evaluation of the smooth adaptation and TCP-friendliness is conducted through a number of simulations with the network simulator software (ns2). Our intention is to use this congestion control in the context of a proposed framework for multimedia transmission over wired and wireless networks.
Designing wireless sensor networks is inherently complex; many aspects such as energy efficiency, limited resources, decentralized collaboration, fault tolerance have to be tackled. To be effective and to produce appl...
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ISBN:
(纸本)9781424433643
Designing wireless sensor networks is inherently complex; many aspects such as energy efficiency, limited resources, decentralized collaboration, fault tolerance have to be tackled. To be effective and to produce applicable results, fundamental research has to be tested, at least as a proof-of-concept, in large scale environments, so as to assess the feasibility of the new concepts, verb their large scale effects (not only at technological level, but also as for their foreseeable implications on users, society and economy) and derive further requirements, orientations and inputs for the research. In this paper we focus on the problems of interconnecting existing testbed environments via the Internet and providing a virtual unifying laboratory that will support academia, research centers and industry in their research on networks and services. In such a facility important issues of trust, security, confidentiality and integrity of data may arise especially for commercial (or not) organizations. In this paper we investigate such issues and present the design of a secure and robust architectural model for interconnecting testbeds of wireless sensor networks.
One of the key objectives of Universal Mobile Telecommunications System (UMTS) is the realization of enhanced end-user experience through the provision of rich multimedia services, ensuring in parallel an economical d...
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In this work we present efficient channel estimation algorithms for wideband detect-and-forward (DF) based relay networks. A generalization of a recently proposed transmission model is utilized and the analysis is com...
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In this work we present efficient channel estimation algorithms for wideband detect-and-forward (DF) based relay networks. A generalization of a recently proposed transmission model is utilized and the analysis is completely performed in the frequency domain (FD). It is shown that all channels in the network from any node to the destination/receiver node can be blindly estimated up to a phase ambiguities vector, related to the source to destination channel frequency response. Hence, by utilizing a small number of pilot symbols, phase ambiguities can be effectively resolved. As verified by computer simulations, the proposed methods exhibit high estimation accuracy even for a short training sequence, and outperform direct training-based channel estimation. A performance study of the proposed schemes in high SNR conditions is also presented and verified through computer simulations.
In this paper, two channel estimation schemes are derived for specific cooperative scenarios. Both schemes are based on the cross-relation criterion that has been extensively studied in the (semi-) blind literature. A...
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In this paper, two channel estimation schemes are derived for specific cooperative scenarios. Both schemes are based on the cross-relation criterion that has been extensively studied in the (semi-) blind literature. As shown in the paper, in a cooperative system, the channel estimator can be constructed in a natural way either by fractionally-spaced or symbol-spaced samples. We investigate the performance of these two schemes using semi-analytic arguments accompanied by corresponding experimental results.
In this paper, electroencephalograph (EEG) signals recorded during miss operation of brain computer interface (BCI) system was analyzed. As a result, a feature difference between miss operation and normal operation wa...
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ISBN:
(纸本)9784907764302
In this paper, electroencephalograph (EEG) signals recorded during miss operation of brain computer interface (BCI) system was analyzed. As a result, a feature difference between miss operation and normal operation was found at the low frequency component and the event-related potential (ERP) such as P300. Therefore a possibility of the modification of miss operation was confirmed.
This paper proposes a method which gives a state space realization of the linear systems with algebraic loops not only in numerical format but also in symbolic format and guarantees that the order of the system is pre...
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ISBN:
(纸本)9781424422210
This paper proposes a method which gives a state space realization of the linear systems with algebraic loops not only in numerical format but also in symbolic format and guarantees that the order of the system is preserved. The method uses an adjacency matrix in graph theory for the modeling of the control systems and uses the matrix inversion lemma to calculate the inverse of matrix symbolically and to obtain the symbolic state space realizations. We have developed a new software platform for modeling and simulation of control systems using the proposed method.
The need for efficient implementation of simple crossbar schedulers has increased in the recent years due to the advent of on-chip interconnection networks that require low latency message delivery. The core function ...
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The need for efficient implementation of simple crossbar schedulers has increased in the recent years due to the advent of on-chip interconnection networks that require low latency message delivery. The core function of any crossbar scheduler is arbitration that resolves conflicting requests for the same output. Since, the delay of the arbiters directly determine the operation speed of the scheduler, the design of faster arbiters is of paramount importance. In this paper, we present a new bit-level algorithm and new circuit techniques for the design of programmable priority arbiters that offer significantly more efficient implementations compared to already-known solutions. From the experimental results it is derived that the proposed circuits are more than 15% faster than the most efficient previous implementations, which under equal delay comparisons, translates to 40% less energy.
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