This paper studies Byzantine reliable broadcast (BRB) under asynchronous networks, and improves the state-of-the-art protocols from the following aspects. Near-optimal communication cost: We propose two new BRB protoc...
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ISBN:
(纸本)9781450392624
This paper studies Byzantine reliable broadcast (BRB) under asynchronous networks, and improves the state-of-the-art protocols from the following aspects. Near-optimal communication cost: We propose two new BRB protocols for.. nodes and input message.. that has communication cost O (n|M |+n(2) logn), which is nearoptimal due to the lower bound of Omega(n|M |+n(2)). The first RBC protocol assumes threshold signature but is easy to understand, while the second RBC protocol is error-free but less intuitive. Improved computation: We propose a newconstruction that improves the computation cost of the state-of-the-art BRB by avoiding the expensive online error correction on the input message, while achieving the same communication cost. Balanced communication: We propose a technique named balanced multicast that can balance the communication cost for BRB protocols where the broadcaster needs to multicast the message.. while other nodes only needs to multicast coded fragments of size O(|M |/n + logn). The balanced multicast technique can be applied to many existing BRB protocols as well as all our new constructions in this paper, and can make every node incur about the same communication cost. Finally, we present a lower bound to show the near optimality of our protocol in terms of communication cost at each node.
We consider the parallel computing environment where m organizations provide machines and several jobs to be executed. While cooperation of organizations is required to minimize the global makespan, each organization ...
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ISBN:
(纸本)9781424452910
We consider the parallel computing environment where m organizations provide machines and several jobs to be executed. While cooperation of organizations is required to minimize the global makespan, each organization also expects the faster completion of its own jobs primarily and thus it is not necessarily cooperative. To handle the situations, we formulate the alpha-cooperative multi-organization scheduling problem (alpha-MOSP), where alpha >= 1 is a parameter representing the degree of cooperativeness. alpha-MOSP minimizes the makespan under the cooperation constraint that each organization does not allow the completion time of its own jobs to be delayed alpha times of that in the case where those jobs are executed by itself. In this paper, we aim to reveal the relation between the makespan and the degree of cooperativeness. First, we investigate the relation between alpha and the quality of the global makespan. For alpha = 1 (i.e., each organization never sacrifices its completion time), we show an instance where the cooperation constraint degrades the optimal makespan by m times. In contrast, for alpha > 1, we can construct an algorithm transforming any unconstrained schedule to one satisfying the cooperation constraint. This algorithm bounds the degradation ratio by alpha/(alpha - 1), which implies that weak cooperation improves the makespan dramatically. Second, we study the complexity of alpha-MOSP. We show its strongly NP-hardness and inapproximability for the approximation factor less than max{(alpha 1)/alpha,3/2}. We also show the hardness of transformation: Even if an optimal schedule under no cooperation constraint is given, no polynomial-time algorithm finds an optimal schedule for a-MOSP. This result is a witness for inexistence of general polynomial-time transformation algorithms that preserve the approximation ratio.
We present a robust algorithm that registers one point set to another for nonrigid case. We formulate the problem as a Gaussian mixture model (GMM) density estimation by considering one of the point sets as the GMM ce...
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ISBN:
(纸本)9781479966837
We present a robust algorithm that registers one point set to another for nonrigid case. We formulate the problem as a Gaussian mixture model (GMM) density estimation by considering one of the point sets as the GMM centroids and the other as the data points generated by GMM. We displace the centroids and make them register to the data by maximizing the likelihood. To facilitate the process, we introduce a set of weights which provide the proximity information among pairs of points of both point sets and iteratively update the displacement and weights in alternating steps. We propose a priority based combination to update the proximity weights, which leverages the richness of Shape Context (SC). In the displacement updation step, we propose a graph-Laplacian regularization which helps in preserving the intrinsic geometry of the point set to be displaced. We also introduce a fast algorithm that reduces the computation complexity significantly. We apply our method on publicly available datasets. Our results validate the robustness of our approach by outperforming current state-of-the-art methods.
Designing an effective and reliable routing protocol to ensure communications between Connected and Autonomous Vehicles (CAVs) is a big challenge. In this paper, we improve the Ad-hoc on-demand distance vector (AODV) ...
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ISBN:
(纸本)9781728167435
Designing an effective and reliable routing protocol to ensure communications between Connected and Autonomous Vehicles (CAVs) is a big challenge. In this paper, we improve the Ad-hoc on-demand distance vector (AODV) routing protocol and propose a minimum delay routing algorithm to minimize the end-to-end packet delay for each vehicular data flow. The algorithm complexity is comparable to that of the existing Bellman-Ford algorithm. Specifically, we build a simulation platform based on the Simulation of Urban Mobility (SUMO). The simulation results show that in such settings, our proposed routing protocol outperforms the existing routing protocols in quality of service performance.
Two decades ago, FastSLAM algorithm for mobile robots was introduced. Since then, dozens of research work focused on FastSLAM algorithm performance enhancement while keeping reduced computation cost. Since experimenta...
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ISBN:
(纸本)9781728137872
Two decades ago, FastSLAM algorithm for mobile robots was introduced. Since then, dozens of research work focused on FastSLAM algorithm performance enhancement while keeping reduced computation cost. Since experimental evaluation of computation cost is dependent on the hardware capabilities of the platform, the present work introduces a quantitative theoretical method for predicting the computation cost of the FastSLAM algorithm. The method relies on the big (0) computation complexity which represents the worst case. The method was evaluated experimentally with different number of particles and different number of map features. The computation cost evaluation analysis was broken down into prediction, observation, data association and resampling computation cost evaluation. The proposed method was proven to be helpful in customization of FastSLAM parameters like number of particles and data association optimization for FastSLAM algorithm developers.
Partially constrained human recognition through periocular region has emerged as a new paradigm in biometric security. This article proposes Phase Intensive Global Pattern (PIGP) : a novel global feature based on vari...
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ISBN:
(纸本)9781479953646
Partially constrained human recognition through periocular region has emerged as a new paradigm in biometric security. This article proposes Phase Intensive Global Pattern (PIGP) : a novel global feature based on variation of intensity of a pixel-neighbours with respect to different phases. The feature thus extracted is claimed to be rotation invariant and hence useful to identify human from images with face-tilt. The performance of proposed feature is experimented on UBIRISv2 database, which is a very large standard dataset with unconstrained periocular images captured under visible spectrum. The proposed work has been compared with Circular Local Binary Pattern (CLBP), and Walsh Transform, and experimentally found to yield higher accuracy, though with increased computation complexity and increased size of the feature vector.
When the code length is moderate, non-binary low-density parity-check (NB-LDPC) codes can achieve better error-correcting performance than their binary counterparts at the cost of higher decoding complexity. The check...
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ISBN:
(纸本)9781612848570
When the code length is moderate, non-binary low-density parity-check (NB-LDPC) codes can achieve better error-correcting performance than their binary counterparts at the cost of higher decoding complexity. The check node processing is a major bottleneck of NB-LDPC decoding. Its computation complexity can be reduced by an iterative forward-backward scheme. Nevertheless, large memory is required in this scheme to store intermediate results. In this paper, a novel check node processing scheme and corresponding VLSI architectures are proposed for the Min-max NB-LDPC decoding. The proposed scheme first sorts out a limited number of the most reliable input messages. Then the forward and backward processes are carried out using only these messages. In addition, an innovative approach is developed to derive the output messages from only a small number of intermediate results without noticeable performance loss. Accordingly, both the memory requirement and computation complexity are greatly reduced. For an example (837, 726) NB-LDPC code over GF(2(5)), our proposed check node processing architecture can achieve at least 34% area reduction and about the same throughput compared to previous efforts based on the original forward-backward scheme.
In this paper, a refined template selection algorithm was proposed for NR-based image feature extraction. The proposed method was devoted to reduce the computation complexity and to improve the recognition ability. Ex...
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ISBN:
(纸本)9781479951512
In this paper, a refined template selection algorithm was proposed for NR-based image feature extraction. The proposed method was devoted to reduce the computation complexity and to improve the recognition ability. Experimental results on several image databases strongly demonstrated the efficiency and effectiveness of the proposed method.
Recently, large contents in the Internet have increased loads of contents servers, networks and data centers, which may degrade the quality of services. To overcome this problem, some mirror servers providing the same...
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ISBN:
(纸本)9781479963874
Recently, large contents in the Internet have increased loads of contents servers, networks and data centers, which may degrade the quality of services. To overcome this problem, some mirror servers providing the same contents are located on a network and a request is navigated to one of the mirror servers. A user must access to one of the servers and the hop length of a path from a user to a server should be short even during link failure. As it affects the performance, the location of the mirror servers is important. In this paper, we address the server location problem, which determines the location of the servers satisfying the following the constraint: any users can access servers within a small hop count even if some links fail. First, we formulate this problem and prove that it is NP-hard. Second, we present a polynomial-time algorithm for the case that the number of simultaneously failed links is restricted to one and the increase of the distance between a user node and servers during failure is restricted to be the number of nodes. Furthermore, we also present an approximation algorithm to solve this problem when the number of servers to be accessed is restricted to one and the number of simultaneously failed links is a constant positive integer, and we evaluate the performance by using some actual network topologies.
For a cognitive radio network (CRN) in which a set of secondary users (SU) competes for a limited number of channels (spectrum resources) belonging to primary user, the channel allocation is a challenge and dominates ...
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ISBN:
(纸本)9781509016983
For a cognitive radio network (CRN) in which a set of secondary users (SU) competes for a limited number of channels (spectrum resources) belonging to primary user, the channel allocation is a challenge and dominates the throughput and congestion of the network. In this paper, the channel allocation problem is first formulated as the 0-1 integer programming optimization, with considering the overall utility both of primary system and secondary system. Inspired by matching theory, a many-to-one matching mechanism is used to remodel the channel allocation problem, and the corresponding PU proposing deferred acceptance (PPDA) algorithm is also proposed to yield a stable matching. We compare the performance and computation complexity between these two solutions. Numerical results demonstrate the efficiency and obtain the communication overhead of the proposed schemes.
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