The connection between two secondary users (SUs) in cognitive radio networks (CRNs) is not only determined by their transmission power and distance, it also depends on the availability of a common channel for both SUs...
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ISBN:
(纸本)9781450350495
The connection between two secondary users (SUs) in cognitive radio networks (CRNs) is not only determined by their transmission power and distance, it also depends on the availability of a common channel for both SUs to open it for communication. Due to dependency on channel availability, communication in CRNs is more challenging than traditional wireless networks. A CRN is said to be connectable if there exists a channel assignment under which all the SUs are connected by either bidirectional link or bidirectional path. In CRN, each SU is equipped with a number of antennas which is the maximum number of channels that it can open simultaneously, known as antenna constraint. As each SU has a limit on the maximum number of channels it can open simultaneously, the network may not be connectable. But, it is desirable to connect the largest subset of SUs when all the SUs of a given CRN can not be connected satisfying antenna constraint while minimizing severe interference introduced due to the nearby transmissions among SUs on the same channel. In this paper, we propose a distributed topology control algorithm with message complexity O(n(2)), which aims to connect the largest subset of SUs with robustness constraint (the network will not be partitioned when any primary user reclaims channel) and ensures conflict free transmissions among SUs, where n is the number of SUs. To address this NP-hard problem, we combine both topology control and channel assignment phase. In topology control phase, a network subgraph with bounded degree is derived with satisfying antenna resource constraint. In channel assignment phase, we utilize graph coloring algorithm to ensure conflict-free property. To the best of our knowledge, this is the first attempt to develop a distributed topology control algorithm when a given CRN is not connectable.
Traditional swarm robots mainly rely on a single GPS for *** environment or the failure of the GPS receiver may cause some robots cannot be located because their GPS signals lose,so co
Traditional swarm robots mainly rely on a single GPS for *** environment or the failure of the GPS receiver may cause some robots cannot be located because their GPS signals lose,so co
In power system operation, the economic dispatch problem (EDP) aims to minimize the total generation cost while meeting the demand and satisfying generator capacity limits. This paper proposes an algorithm based on th...
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In power system operation, the economic dispatch problem (EDP) aims to minimize the total generation cost while meeting the demand and satisfying generator capacity limits. This paper proposes an algorithm based on the gradient push-sum method to solve the EDP in a distributed manner over communication networks potentially with time-varying topologies and communication delays. This paper shows that the proposed algorithm is guaranteed to solve the EDP if the time-varying directed communication network is uniformly jointly strongly connected. Moreover, the proposed algorithm is also able to handle arbitrarily large but bounded time-varying delays on communication links. Numerical simulations are used to illustrate and validate the proposed algorithm.
The deployment of sensor nodes (SNs) to form a network with coverage ability is one of the most important challenges of wireless sensor networks. In this paper, we study an efficient distributed deployment algorithm f...
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The deployment of sensor nodes (SNs) to form a network with coverage ability is one of the most important challenges of wireless sensor networks. In this paper, we study an efficient distributed deployment algorithm for barrier coverage improvement with mobile sensors, in which the SNs can be relocated after the initial deployment. To achieve the maximum number of barriers, we propose a distributed algorithm to construct k-barrier coverage by relocation of the SNs. Different from existing approaches, we propose a novel clustering technique based on the network area to reduce the information exchange messages. Then, based on the SNs clusters, we propose a heuristic method to assign the SNs evenly into each cluster with regard to the required number of SNs of each cluster and decide the moving SNs by computing the optimal relocation, considering moving distance minimization. The main goal of this approach is to relocate the SNs to form the maximum number of barriers with a minimum relocation cost, in terms of sensor energy consumption of communication and movement. The simulation results demonstrate the effectiveness of our algorithm when compared with other competing approaches.
Industrial environments are typically characterised by high levels of interference. Therefore, standards for industrial wireless sensor networks (WirelessHART, ISA 100.11a, and IEEE 802.15.4e) have defined a time divi...
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ISBN:
(纸本)9781538635902
Industrial environments are typically characterised by high levels of interference. Therefore, standards for industrial wireless sensor networks (WirelessHART, ISA 100.11a, and IEEE 802.15.4e) have defined a time division and multichannel-based mode of operation, in which time slots and channel pairs are assigned to links representing communication between nodes. In IEEE 802.15.4e this mode of operation is called Timed Slotted Channel Hopping (TSCH). In this paper we describe a distributed algorithm to define such an assignment for a given wireless network. In particular, the algorithm is efficient, scalable and was developed for the Signal-to-Interference-plus-Noise-Ratio (SINR) model, currently considered the most appropriate to develop and analyse algorithms for wireless networks when interference is taken into consideration. Previous approaches to this problem are mainly centralised, based on a simple (or none) interference model or do not consider multiple physical channels. The described algorithm applies also to the Internet of Things, characterised by high scale and presence of interference.
The class of CRC constraints generalizes several tractable classes of constraints and is expressive enough to model problems in domains such as temporal reasoning, geometric reasoning, and scene labelling. This paper ...
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ISBN:
(纸本)9781510855076
The class of CRC constraints generalizes several tractable classes of constraints and is expressive enough to model problems in domains such as temporal reasoning, geometric reasoning, and scene labelling. This paper presents the first distributed deterministic algorithm for connected row-convex (CRC) constraints. Our distributed (partial) path consistency algorithm efficiently transforms a CRC constraint network into an equivalent constraint network, where all constraints are minimal (i.e., they are the tightest constraints) and generating all solutions can be done in a backtrackfree manner. When compared with the state-of-the-art distributed algorithm for CRC constraints, which is a randomized one, our algorithm guarantees to generate a solution for satisfiable CRC constraint networks and it is applicable to solve large networks in real distributed systems. The experimental evaluations show that our algorithm outperforms the state-of-the-art algorithm in both practice and theory.
A certifying algorithm verifies the correctness of its output at runtime by producing a witness in addition to an input-output pair. If a witness predicate holds for the triple, the input-output pair is correct. A che...
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ISBN:
(纸本)9783319675312;9783319675305
A certifying algorithm verifies the correctness of its output at runtime by producing a witness in addition to an input-output pair. If a witness predicate holds for the triple, the input-output pair is correct. A checker algorithm decides the witness predicate. While certifying sequential algorithms are well-established, we consider distributed algorithms. In this paper, we investigate certifying distributed algorithms that verify their distributed output. While the witness predicate states a property in the network, for distributed checking, additional predicates are decided for each component. We illustrate the applicability by examples.
This paper discusses the global version of the critical section (CS) problems including mutual exclusion and mutual inclusion. The global (l, k)-CS problem is the problem of controlling the system in such a way that, ...
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ISBN:
(纸本)9781538620878
This paper discusses the global version of the critical section (CS) problems including mutual exclusion and mutual inclusion. The global (l, k)-CS problem is the problem of controlling the system in such a way that, at least 1 processes must be in the CS and at least n - k processes must be out of the CS at a time in the network where n is the number of processes. In this paper, a distributed solution is proposed based on an asynchronous message-passing model. It is proposed with O(vertical bar Q vertical bar) message complexity, where vertical bar Q vertical bar is the maximum size for the quorum of a coterie used by the algorithm, which is typically vertical bar Q vertical bar = root n.
This paper presents a distributed algorithmic solution for assembling of swarm of asynchronous mobile robots on the left boundary of a given rectangular region in presence of line obstacles by synchronizing them using...
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ISBN:
(纸本)9781509043071
This paper presents a distributed algorithmic solution for assembling of swarm of asynchronous mobile robots on the left boundary of a given rectangular region in presence of line obstacles by synchronizing them using visible bits. Each robot is equipped with light bulb with 3 different colors (off, blue and red). The color of the light bulb is visible to itself and to all the other robots and is also persistent. All the robots execute same algorithm based on the same snapshot to compute the destination. We are considering asynchronous timing model and CORDA model for computation. The proposed algorithm uses visible bits to synchronize the asynchronous robots.
With the development of the Internet of Things (IoT), more and more devices that have diverse computing and communication capabilities are interconnected. For,multimedia multicast in the IoT, a fixed flow rate cannot ...
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With the development of the Internet of Things (IoT), more and more devices that have diverse computing and communication capabilities are interconnected. For,multimedia multicast in the IoT, a fixed flow rate cannot meet the quality-of-service requirements of heterogeneous devices and each device may not get the information from all other devices. In order to satisfy the heterogeneous requirements, we develop a distributed algorithm to solve the inter-layer flow optimization problem based on network coding for multimedia multicast in the IoT, by using primal decomposition and primal-dual analysis. We also apply Lyapunov theory to prove the convergence and global stability of the proposed iterative algorithm. Numerical results demonstrate that the proposed algorithm has better flexibility, stability, and implementation advantages than the previous intra-layer ones. (C) 2015 Elsevier Ltd. All rights reserved.
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