共查询到20条相似文献,搜索用时 31 毫秒
1.
Byeong Il Lee Jae Sung Lee Dong Soo Lee Won Jun Kang Jong Jin Lee Seungjin Choi 《The Journal of VLSI Signal Processing》2007,49(2):233-241
Ensemble independent component analysis (ICA) is a Bayesian multivariate data analysis method which allows various prior distributions
for parameters and latent variables, leading to flexible data fitting. In this paper we apply ensemble ICA with a rectified
Gaussian prior to dynamic positron emission tomography (PET) image data, emphasizing its clinical usefulness by showing that major cardiac components
are successfully extracted in an unsupervised manner and myocardial blood flow can be estimated in 15 among 20 patients. Detailed
experiments and results are illustrated.
相似文献
Seungjin ChoiEmail: |
2.
Expressions are given for the moment generating functions of the Rayleigh and generalized Rayleigh distributions.
相似文献
Saralees NadarajahEmail: |
3.
Parallelization of operations is of utmost importance for efficient implementation of Public Key Cryptography algorithms.
Starting with a classification of parallelization methods at different abstraction levels of public key algorithms, we propose
a novel memory architecture for elliptic curve implementations with multiple modular multiplier units. This architecture is
well-suited for different point addition and doubling algorithms over to be implemented on FPGAs. It allows the execution time to scale with the number of modular multipliers and exhibits nearly
no overhead compared to the mere runtime of the multipliers. The advantages of this distributed memory architecture are demonstrated
by means of two different point addition and doubling algorithms.
相似文献
Sorin A. HussEmail: |
4.
We investigate a unique wireless sensor network scheduling problem in which all nodes in a cluster send exactly one packet
to a designated sink node in an effort to minimize transmission time. However, node transmissions must be sufficiently isolated
either in time or in space to avoid collisions. The problem is formulated and solved via graph representation. We prove that
an optimal transmission schedule can be obtained efficiently through a pipeline-like schedule when the underlying topology
is either line or tree. The minimum time required for a line or tree topology with nodes is . We further prove that our scheduling problem is NP-hard for general graphs. We propose a heuristic algorithm for general
graphs. Our heuristic tries to schedule as many independent segments as possible to increase the degree of parallel transmissions. This algorithm is compared to an RTS/CTS based distributed
algorithm. Preliminary simulated results indicate that our heuristic algorithm outperforms the RTS/CTS based distributed algorithm
(up to 30%) and exhibits stable behavior.
相似文献
Esther A. HughesEmail: |
5.
Marcio Juliato Guido Araujo Julio López Ricardo Dahab 《The Journal of VLSI Signal Processing》2007,47(1):59-76
This paper presents a comprehensive analysis of the design of custom instructions in a reconfigurable hardware platform dedicated
to accelerate arithmetic operations in the binary field , using a Gaussian normal basis representation. The resulting platform is capable of running real applications, thus allowing
a precise measurement of the execution overheads, and a fair comparison of the hardware and software speedups at several implementation
levels. By using this approach, we determine which field operations (e.g., multiplication) are better suited to constrained
environments, and which ones provide an enhanced performance in general-purpose systems. Experimental results reveal that
by using our fastest field multiplier implemented as a custom instruction in a combined hardware/software approach, we accelerate
point multiplication (the fundamental operation in Elliptic Curve Cryptography) over 126 times.
相似文献
Ricardo DahabEmail: |
6.
Essia Hamouda Nathalie Mitton Bogdan Pavkovic David Simplot-Ryl 《International Journal of Wireless Information Networks》2009,16(3):142-153
We propose, end-to-end (EtE), a novel EtE localized routing protocol for wireless sensor networks that is energy-efficient
and guarantees delivery. To forward a packet, a node s in graph G computes the cost of the energy weighted shortest path (SP) between s and each of its neighbors in the forward direction towards the destination which minimizes the ratio of the cost of the SP
to the progress (reduction in distance towards the destination). It then sends the message to the first node on the SP from
s to x: say node x′. Node x′ restarts the same greedy routing process until the destination is reached or an obstacle is encountered and the routing
fails. To recover from the latter scenario, local minima trap, our algorithm invokes an energy-aware Face routing that guarantees
delivery. Our work is the first to optimize energy consumption of Face routing. It works as follows. First, it builds a connected
dominating set from graph G, second it computes its Gabriel graph to obtain the planar graph G′. Face routing is invoked and applied to G′ only to determine which edges to follow in the recovery process. On each edge, greedy routing is applied. This two-phase
(greedy–Face) EtE routing process reiterates until the final destination is reached. Simulation results show that EtE outperforms
several existing geographical routing on energy consumption metric and delivery rate. Moreover, we prove that the computed
path length and the total energy of the path are constant factors of the optimal for dense networks.
Essia Hamouda received the BSc and the MS degree in Industrial and Systems Engineering from the Ohio State University and the University of Florida, respectively. She received a PhD in Computer Science from the University of California Riverside. Her research interests are in the areas of sensor and mobile ad hoc networks and performance evaluation of computer networks. Nathalie Mitton is currently an INRIA full researcher. Her research interests are mainly focused on theoretical aspects of self-organization, self-stabilization, energy efficient routing and neighbour discovery algorithms for wireless sensor networks as well as RFID middlewares. She is involved in several program and organization committees such as ADHOC NOW 2009, SANET 2008 and 2007. Bogdan Pavkovic received a MSc in Microprocessor and computer electronics from the Faculty of Technical Sciences in Novi Sad, University of Novi Sad in May of 2009. From May to December of 2009 he was an intern at INRIA, Lille—Nord Europe, France. His research interest include embedded systems and applied electronic, robotics and automated vehicles, sensor and mobile ad hoc networks and RFID technologies. David Simplot-Ryl received the PhD degree in computer science in 1997 from the University of Lille, France. He is now a professor at the University of Lille 1 and head of the POPS research team at the INRIA research centre Lille—Nord Europe. His research interests are in the areas of sensor and mobile ad hoc networks, mobile and distributed computing, and RFID technologies. He is editor and guest editor of several journals, cochair of conferences and workshop. Since 2008, he is scientific deputy of the INRIA research centre Lille—Nord Europe. 相似文献
Essia Hamouda (Corresponding author)Email: |
Nathalie MittonEmail: |
Bogdan PavkovicEmail: |
David Simplot-RylEmail: |
Essia Hamouda received the BSc and the MS degree in Industrial and Systems Engineering from the Ohio State University and the University of Florida, respectively. She received a PhD in Computer Science from the University of California Riverside. Her research interests are in the areas of sensor and mobile ad hoc networks and performance evaluation of computer networks. Nathalie Mitton is currently an INRIA full researcher. Her research interests are mainly focused on theoretical aspects of self-organization, self-stabilization, energy efficient routing and neighbour discovery algorithms for wireless sensor networks as well as RFID middlewares. She is involved in several program and organization committees such as ADHOC NOW 2009, SANET 2008 and 2007. Bogdan Pavkovic received a MSc in Microprocessor and computer electronics from the Faculty of Technical Sciences in Novi Sad, University of Novi Sad in May of 2009. From May to December of 2009 he was an intern at INRIA, Lille—Nord Europe, France. His research interest include embedded systems and applied electronic, robotics and automated vehicles, sensor and mobile ad hoc networks and RFID technologies. David Simplot-Ryl received the PhD degree in computer science in 1997 from the University of Lille, France. He is now a professor at the University of Lille 1 and head of the POPS research team at the INRIA research centre Lille—Nord Europe. His research interests are in the areas of sensor and mobile ad hoc networks, mobile and distributed computing, and RFID technologies. He is editor and guest editor of several journals, cochair of conferences and workshop. Since 2008, he is scientific deputy of the INRIA research centre Lille—Nord Europe. 相似文献
7.
In this paper, we study an algorithmic model for wireless ad hoc and sensor networks that aims to be sufficiently close to
reality as to represent practical realworld networks while at the same time being concise enough to promote strong theoretical
results. The quasi unit disk graph model contains all edges shorter than a parameter d between 0 and 1 and no edges longer than 1. We show that—in comparison to the cost known for unit disk graphs—the complexity
results of geographic routing in this model contain the additional factor 1/d
2. We prove that in quasi unit disk graphs flooding is an asymptotically message-optimal routing technique, we provide a geographic
routing algorithm being most efficient in dense networks, and we show that classic geographic routing is possible with the
same asymptotic performance guarantees as for unit disk graphs if .
相似文献
Aaron Zollinger (Corresponding author)Email: |
8.
Jérôme Galtier 《Wireless Networks》2009,15(6):791-803
The paper addresses the need of controling the access of terminals with guaranteed ressources on the high dynamic systems offered by LEO satellite constellations. A call-access-control scheme that guarantees the reservation of permanent resources of satellite constellations in $O(\sqrt(n)\hbox{log}(n))The paper addresses the need of controling the access of terminals with guaranteed ressources on the high dynamic systems
offered by LEO satellite constellations. A call-access-control scheme that guarantees the reservation of permanent resources
of satellite constellations in time, where n is the number of user present in the system, is described. A tradeoff between computational time of call-access-control and
optimization of the use of the spectrum is identified. Some experimental results are presented.
相似文献
Jér?me GaltierEmail: |
9.
Saralees Nadarajah 《Wireless Personal Communications》2009,49(4):575-585
The quantization error for MIMO (multiple-input multiple-output) downlink channels is known to be the minimum of independent
and identically distributed beta random variables. In this note, an exact expression is derived for the average quantization
error. Computational issues relating to its correctness, usage and approximations are discussed.
相似文献
Saralees NadarajahEmail: |
10.
Grzegorz Mrugalski Janusz Rajski Chen Wang Artur Pogiel Jerzy Tyszer 《Journal of Electronic Testing》2007,23(1):35-45
This paper describes a non-recursive fault diagnosis technique for scan-based designs with convolutional test response compaction.
The proposed approach allows a time-efficient and accurate identification of failing scan cells using Gauss–Jordan elimination
method.
相似文献
Jerzy Tyszer (Corresponding author)Email: |
11.
For applications requiring a large dynamic, real numbers may be represented either in floating-point, or in the logarithm
number system (LNS). Which system is best for a given application is difficult to know in advance, because the cost and performance
of LNS operators depend on the target accuracy in a highly non linear way. Therefore, a comparison of the pros and cons of
both number systems in terms of cost, performance and overall accuracy is only relevant on a per-application basis. To make
such a comparison possible, two concurrent libraries of parameterized arithmetic operators, targeting recent field-programmable
gate arrays, are presented. They are unbiased in the sense that they strive to reflect the state-of-the-art for both number
systems. These libraries are freely available at .
相似文献
Jérémie Detrey (Corresponding author)Email: |
Florent de DinechinEmail: |
12.
Elliptic curve cryptography (ECC) is recognized as a fast cryptography system and has many applications in security systems.
In this paper, a novel sharing scheme is proposed to significantly reduce the number of field multiplications and the usage
of lookup tables, providing high speed operations for both hardware and software realizations.
相似文献
Brian KingEmail: |
13.
The paper summarizes the main results of one of the key panel session of the Workshop, focused on the investigation about
the possible translation of the “layerless communications” from a dreaming vision to reality.
相似文献
Juha SaarnioEmail: |
14.
Sakib A. Mondal 《Wireless Networks》2009,15(3):331-340
Mobile IP is a network layer protocol for handling mobility of hosts in the Internet. However, mobile IP handoff causes degradation
of TCP performance. Hence, there is a need for improving performance of TCP over mobile IP in wireless mobile networks. We
propose an approach which handles losses due to both wireless link errors and host mobility. To handle losses due to host
mobility, a method for seamless handoff is proposed. Empirical results show that the scheme provides substantial improvement
of performance.
Sakib A. Mondal is a Senior Researcher at General Motors Research. He has received his doctorate in Management Information Systems from Indian Institute of Management Calcutta, and has worked for almost twelve years in various areas of Information Technology. His research interests include mobile and distributed computing, performance engineering, optimization and heuristic search. 相似文献
Sakib A. MondalEmail: |
Sakib A. Mondal is a Senior Researcher at General Motors Research. He has received his doctorate in Management Information Systems from Indian Institute of Management Calcutta, and has worked for almost twelve years in various areas of Information Technology. His research interests include mobile and distributed computing, performance engineering, optimization and heuristic search. 相似文献
15.
To support distributive tracking of moving targets in a wireless sensor network, sensors that receive signal from the same
target must collaborate to facilitate collaborative, distributed target tracking. We present an efficient dynamic sensor self-organizing
algorithm that clusters sensors into groups without requiring a centralized control. Extensive simulations are conducted to
verify the performance improvement as well as the communication reduction for the proposed methods.
相似文献
Xiaohong ShengEmail: |
16.
In this work the performance of a Fractional Fourier transform (FrFT) based Minimum Mean Squared Error receiver for MIMO systems
with space time processing over Rayleigh faded channels is presented. The proposed receiver called Optimum FrFT based MIMO
receiver (OFMR) shows improved performance outperforming the simple MMSE receiver in Rayleigh faded channel.
相似文献
Rajesh KhannaEmail: Email: |
17.
A New Routing Metric for Satisfying Both Energy and Delay Constraints in Wireless Sensor Networks 总被引:1,自引:0,他引:1
Besides energy constraint, wireless sensor networks should also be able to provide bounded communication delay when they are
used to support real-time applications. In this paper, a new routing metric is proposed. It takes into account both energy
and delay constraints. It can be used in AODV. By mathematical analysis and simulations, we have shown the efficiency of this
new routing metric.
相似文献
YeQiong SongEmail: |
18.
Chen Jie Vidhyacharan Bhaskar 《International Journal of Wireless Information Networks》2008,15(1):53-60
This paper analyzes the distribution and density functions of the probability of error for Rayleigh and Rician fading channels
with diversity. An expression for the signal-to-noise ratio is derived for an asynchronous CDMA (A-CDMA) system with diversity.
The error probability distribution and density functions are derived and plotted for different mean energy-to-noise ratios.
相似文献
Vidhyacharan BhaskarEmail: |
19.
Xianyi Rui 《Wireless Personal Communications》2009,50(2):133-142
The effect of co-channel interference (CCI) is considered in multiple-input multiple-output (MIMO) systems employing maximal
ratio combining (MRC) under independent and identically distributed Rayleigh fading. Closed-form capacity and symbol error
rate expressions are presented to evaluate the performance without any numerical integrations or statistical simulations.
The analytical results are compared with Monte Carlo simulations and the good agreement is obtained.
相似文献
Xianyi RuiEmail: |
20.
Ireneusz Szcześniak Tadeusz Czachórski Jean-Michel Fourneau 《Photonic Network Communications》2008,16(3):253-261
We present an approximate analytical method for the evaluation of packet loss probability in synchronous optical packet-switched
networks which operate under limited deflection routing with the contention resolution method based on priorities. Packets
are lost because they are removed by nodes. They are removed because they experience too many deflections and stay prohibitively
long in the network. Such packets have to be removed because they will be ignored by the transmission protocols (like TCP)
and because the quality of their optical signal is unacceptable. Presented are results for the network in the topology of
the torus of the two-dimensional grid, which operates at a steady state with the uniform load u, . The strength of our analysis is its novel mathematical approach, which is capable of providing very low packet loss probabilities.
For the network composed of 100 nodes, we predict the packet loss probability as low as 10−9 or lower, while simulation provided results only at the order of 10−6. For a given permissible packet loss probability, our analysis provides the maximal network load and the number of allowed
deflections. We verify the analysis with simulation in the cases for which simulation gave results.
相似文献
Jean-Michel FourneauEmail: |