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Showing papers on "Routing (electronic design automation) published in 2020"


Journal ArticleDOI
TL;DR: This paper presents UAV classification, communication and application architectures, and an exhaustive survey of the existing routing protocols for flying ad hoc networks, and highlights the key features, strengths and weaknesses, and different mobility models used for the performance evaluation of theexisting FANET routing protocols.
Abstract: The use of unmanned aerial vehicles (UAVs) is attracting considerable interest in academic research, commercial, and military applications. Multi-UAV systems organized in an ad hoc fashion called a flying ad hoc network (FANET) can cooperatively and collaboratively accomplish complex missions more efficiently compared to single large UAV systems. However, the unique features of FANETs such as high mobility, low node density, and high frequency of topology changes introduce challenges to the communication design, especially routing. Thus, the routing requirements of FANETs surpass those of MANETs or VANETs. In this paper, we present UAV classification, communication and application architectures, and an exhaustive survey of the existing routing protocols for flying ad hoc networks. Furthermore, we highlight the key features, strengths and weaknesses, and different mobility models used for the performance evaluation of the existing FANET routing protocols. More importantly, a proposed taxonomy and a review on the existing FANET routing protocols are presented. Finally, we highlight the existing challenges and open research issues.

130 citations


ReportDOI
01 Mar 2020
TL;DR: This document describes the Se segment Routing Extension Header and how it is used by Segment Routing capable nodes.
Abstract: Segment Routing can be applied to the IPv6 data plane using a new type of Routing Extension Header. This document describes the Segment Routing Extension Header and how it is used by Segment Routing capable nodes.

119 citations


Journal ArticleDOI
TL;DR: There are various routing techniques, real‐time applications of UAVs which are elaborated in this paper, namely, representative, cooperative, and noncooperative techniques, and collision avoidance techniques which are very important for the obstacle‐free environment.

112 citations


Proceedings Article
30 Apr 2020
TL;DR: This paper presents the first learning based approach for CVRP that is efficient in solving speed and at the same time outperforms OR methods, and achieves the new state-of-the-art results on CVRp.
Abstract: This paper is concerned with solving combinatorial optimization problems, in particular, the capacitated vehicle routing problems (CVRP). Classical Operations Research (OR) algorithms such as LKH3 (Helsgaun, 2017) are extremely inefficient (e.g., 13 hours on CVRP of only size 100) and difficult to scale to larger-size problems. Machine learning based approaches have recently shown to be promising, partly because of their efficiency (once trained, they can perform solving within minutes or even seconds). However, there is still a considerable gap between the quality of a machine learned solution and what OR methods can offer (e.g., on CVRP-100, the best result of learned solutions is between 16.10-16.80, significantly worse than LKH3's 15.65). In this paper, we present the first learning based approach for CVRP that is efficient in solving speed and at the same time outperforms OR methods. Starting with a random initial solution, our algorithm learns to iteratively refines the solution with an improvement operator, selected by a reinforcement learning based controller. The improvement operator is selected from a pool of powerful operators that are customized for routing problems. By combining the strengths of the two worlds, our approach achieves the new state-of-the-art results on CVRP, e.g., an average cost of 15.57 on CVRP-100.

107 citations


Journal ArticleDOI
TL;DR: Simulation results show that the proposed protocol is better than generic Ant Colony Optimization (ACO) and other traditional routing protocols utilized in FANET.
Abstract: The increasing demand of routing in the field of communication is the most important subject in ad hoc networks now a days. Flying Ad Hoc Network (FANET) is one of the emerging areas that evolved from Mobile Ad Hoc Networks. Selecting the best optimal path in any network is a real challenge for a routing protocol. Because the network performance like throughput, Quality of Service (QoS), user experience, response time and other key parameters depend upon the efficiency of the algorithm running inside the routing protocol. The complexity and diversity of the problem is augmented due to dynamic spatial and temporal mobility of FANET nodes. Due to these challenges the performance and efficiency of the routing protocol becomes very critical. This paper presents a novel routing protocol for FANET using modified AntHocNet. Ant colony optimization technique or metaheuristics in general has shown better dependability and performance as compared to other legacy best path selection techniques. Energy stabilizing parameter introduced in this study improves energy efficiency and overall network performance. Simulation results show that the proposed protocol is better than generic Ant Colony Optimization (ACO) and other traditional routing protocols utilized in FANET.

103 citations


Journal ArticleDOI
TL;DR: A model of integrated location, routing, and inventory problem, the three key problems in optimizing a logistics system, is introduced and it is observed that when the goal of sustainability is approached, manufacturing sector tends to be decentralized and the local commodity production in more medium- and low-developed locations can exhibit the best sustainability performance.

97 citations


Journal ArticleDOI
Bin Cao1, Jianwei Zhao1, Yu Gu, Shanshan Fan1, Peng Yang1 
TL;DR: This article simultaneously considers the security, lifetime, and coverage issues by deploying sensor nodes and relay nodes in an industrial environment to analyze the multipath routing for enhancing security and proposes enhanced distributed parallel algorithms that outperform their counterparts.
Abstract: Security is crucial for industrial wireless sensor networks (IWSNs); therefore, in this article, we simultaneously consider the security, lifetime, and coverage issues by deploying sensor nodes and relay nodes in an industrial environment to analyze the multipath routing for enhancing security. For the security issue, the computation of disjoint routing paths is converted to a maximum flow problem. Then, the deployment problem is transformed into a multiobjective optimization problem, which we address by employing six state-of-the-art serial algorithms and two distributed parallel algorithms. Additionally, based on our prior work, by testing random grouping and prior knowledge-based grouping, as well as another optimizer, we propose enhanced distributed parallel algorithms. As verified by experiments, the proposed algorithms outperform their counterparts. Due to the characteristic of distributed parallelism, the time consumed by the proposed algorithms is significantly reduced compared to that of the serial algorithms. Therefore, the proposed algorithms can achieve better performance within a very limited time.

97 citations


Journal ArticleDOI
TL;DR: This paper identifies order picker routing policies in a systematic search of the literature and develops a conceptual framework for categorizing the various policies and derives insights into the frequencies of usage of the different routing policies available in the literature.

97 citations


Journal ArticleDOI
TL;DR: This paper analyzes existing VANET routing protocols, critically compares the existing solutions proposed so far, and presents brief description of emerging WAVE+LTE based technology along with some viable direction for future improvement related to location based routing protocols.

93 citations


Journal ArticleDOI
TL;DR: A new routing protocol called Secured Quality of Service (QoS) aware Energy Efficient Routing Protocol is proposed in this paper which is designed based on trust and energy modelling for enhancing the security of WSN and also to optimize the energy utilization.
Abstract: In Wireless Sensor Network (WSN), the lifetime optimization based on minimal energy consumption and security are the crucial issues for the effective design of protocols to perform multi-hop secure routing. In order to address these issues, we propose a new routing protocol called Secured Quality of Service (QoS) aware Energy Efficient Routing Protocol in this paper which is designed based on trust and energy modelling for enhancing the security of WSN and also to optimize the energy utilization. In this proposed work, the trust modelling uses an authentication technique with a key based security mechanism for providing trust scores. Moreover, three types of trust scores namely direct, indirect and overall trust scores are calculated in this work for enhancing the security of communication. In addition, a cluster based secure routing algorithm is proposed in this work in which the cluster head has been selected based on QoS metrics and trust scores to perform cluster based secure routing. Finally, the final path has been selected based on path-trust, energy and hop count to efficiently carry out the secure routing process. The proposed work has been assessed by simulations carried out using NS2 simulator. The simulation results demonstrate that the proposed algorithm provides better performance in terms of increase in packet delivery ratio, network life time and security. Moreover, it provides reduction in delay and energy consumption when the proposed secure routing algorithm is compared to the other related secure routing algorithms.

90 citations


Journal ArticleDOI
TL;DR: This work develops SDR-based DNA switching circuits (DSCs) that achieve high-speed computing with fewer molecules and expects that DSCs provide a design paradigm for digital computation with biomolecules.
Abstract: DNA strand displacement reactions (SDRs) provide a set of intelligent toolboxes for developing molecular computation. Whereas SDR-based logic gate circuits have achieved a high level of complexity, the scale-up for practical achievable computational tasks remains a hurdle. Switching circuits that were originally proposed by Shannon in 1938 and nowadays widely used in telecommunication represent an alternative and efficient means to realize fast-speed and high-bandwidth communication. Here we develop SDR-based DNA switching circuits (DSCs) for implementing digital computing. Using a routing strategy on a programmable DNA switch canvas, we show that arbitrary Boolean functions can be represented by DSCs and implemented with molecular switches with high computing speed. We further demonstrate the implementation of full-adder and square-rooting functions using DSCs, which only uses down to 1/4 DNA strands as compared with a dual-rail logic expression-based design. We expect that DSCs provide a design paradigm for digital computation with biomolecules.

Journal ArticleDOI
TL;DR: The result shows that under most network performance indicators and parameters, the proposed LLECP-AOMDV is superior to the other three protocols, which improves the network lifetime, reduces the node’s energy consumption and the average end-to-end delay.
Abstract: During mobile edge computing, due to the movement of nodes and the exhaustion of node energy, link failure occurs thus reducing the network lifetime in the mobile ad-hoc network. When the route fails, because the single-path protocols need to restart the route discovery process, the delay of the network is greatly increased. Therefore, the multi-path routing protocol is proposed, saving the cost of route discovery. In this paper, we propose an ad hoc on-demand multi-path distance vector (AOMDV) routing protocol based on link lifetime and energy consumption prediction (named LLECP-AOMDV) for mobile edge computing. In the route discovery phase, the energy grading strategy is adopted. When the node energy is lower than the threshold, it no longer participates in the route discovery. In the routing selected phase, the path is selected based on the lifetime of the route link and the minimum energy consumption of the route. According to energy consumption, packet delivery rate, end-to-end delay performance indicators, we evaluate the comparison results. The result shows that under most network performance indicators and parameters, the proposed LLECP-AOMDV is superior to the other three protocols, which improves the network lifetime, reduces the node's energy consumption and the average end-to-end delay. The protocol is very useful for mobile edge computing.

Journal ArticleDOI
Zongshan Wang1, Hongwei Ding1, Bo Li1, Liyong Bao1, Zhijun Yang 
TL;DR: A clustering algorithm that selects cluster heads using an improved artificial bee colony (ABC) algorithm and an energy-efficient routing algorithm based on an improved ant colony optimization for routing between the cluster heads and the base station are proposed.
Abstract: Clustering sensor nodes is an effective method in designing routing algorithms for Wireless Sensor Networks (WSNs), which improves network lifetime and energy efficiency. In clustered WSNs, cluster heads are the key nodes, they need to perform more tasks, so they consume more energy. Therefore, it is an important problem to select the optimal cluster heads. In this paper, we propose a clustering algorithm that selects cluster heads using an improved artificial bee colony (ABC) algorithm. Based on the standard ABC algorithm, an efficient improved ABC algorithm is proposed, and then the network cluster head energy, cluster head density, cluster head location and other similar factors are introduced into the improved ABC algorithm theory to solve the clustering problem in WSNs. In the network initialization period, all nodes have the same energy level, the improved ABC algorithm is used to optimize fuzzy C-means clustering to find the optimal clustering method. We also propose an energy-efficient routing algorithm based on an improved ant colony optimization for routing between the cluster heads and the base station. In order to improve energy efficiency and further improve network throughput, in the stable transmission phase, we introduce a polling control mechanism based on busy/idle nodes into intra-cluster communication. The performance of the proposed protocol is evaluated in several different scenarios. The simulation results show that the proposed protocol has a better performance compared to a number of recent similar protocols.

Proceedings ArticleDOI
14 Jun 2020
TL;DR: This paper proposes to search block counts and block widths by designing a densely connected search space, i.e., DenseNAS, represented as a dense super network, which is built upon the designed routing blocks.
Abstract: Neural architecture search (NAS) has dramatically advanced the development of neural network design. We revisit the search space design in most previous NAS methods and find the number and widths of blocks are set manually. However, block counts and block widths determine the network scale (depth and width) and make a great influence on both the accuracy and the model cost (FLOPs/latency). In this paper, we propose to search block counts and block widths by designing a densely connected search space, i.e., DenseNAS. The new search space is represented as a dense super network, which is built upon our designed routing blocks. In the super network, routing blocks are densely connected and we search for the best path between them to derive the final architecture. We further propose a chained cost estimation algorithm to approximate the model cost during the search. Both the accuracy and model cost are optimized in DenseNAS. For experiments on the MobileNetV2-based search space, DenseNAS achieves 75.3% top-1 accuracy on ImageNet with only 361MB FLOPs and 17.9ms latency on a single TITAN-XP. The larger model searched by DenseNAS achieves 76.1% accuracy with only 479M FLOPs. DenseNAS further promotes the ImageNet classification accuracies of ResNet-18, -34 and -50-B by 1.5%, 0.5% and 0.3% with 200M, 600M and 680M FLOPs reduction respectively. The related code is available at https://github.com/JaminFong/DenseNAS.

Proceedings ArticleDOI
30 Jul 2020
TL;DR: Evaluation results show that the proposed algorithm Q-CAST increases the number of successful long-distance entanglements by a big margin compared to other methods, and may encourage more network researchers to study the entanglement routing problem.
Abstract: Quantum entanglement enables important computing applications such as quantum key distribution. Based on quantum entanglement, quantum networks are built to provide long-distance secret sharing between two remote communication parties. Establishing a multi-hop quantum entanglement exhibits a high failure rate, and existing quantum networks rely on trusted repeater nodes to transmit quantum bits. However, when the scale of a quantum network increases, it requires end-to-end multi-hop quantum entanglements in order to deliver secret bits without letting the repeaters know the secret bits. This work focuses on the entanglement routing problem, whose objective is to build long-distance entanglements via untrusted repeaters for concurrent source-destination pairs through multiple hops. Different from existing work that analyzes the traditional routing techniques on special network topologies, we present a comprehensive entanglement routing model that reflects the differences between quantum networks and classical networks as well as a new entanglement routing algorithm that utilizes the unique properties of quantum networks. Evaluation results show that the proposed algorithm Q-CAST increases the number of successful long-distance entanglements by a big margin compared to other methods. The model and simulator developed by this work may encourage more network researchers to study the entanglement routing problem.

Journal ArticleDOI
TL;DR: This work studies the joint optimization of service placement and request routing in dense MEC networks with multidimensional constraints and proposes an algorithm that achieves close-to-optimal performance using a randomized rounding technique.
Abstract: The proliferation of innovative mobile services such as augmented reality, networked gaming, and autonomous driving has spurred a growing need for low-latency access to computing resources that cannot be met solely by existing centralized cloud systems. Mobile Edge Computing (MEC) is expected to be an effective solution to meet the demand for low-latency services by enabling the execution of computing tasks at the network edge, in proximity to the end-users. While a number of recent studies have addressed the problem of determining the execution of service tasks and the routing of user requests to corresponding edge servers, the focus has primarily been on the efficient utilization of computing resources, neglecting the fact that non-trivial amounts of data need to be pre-stored to enable service execution, and that many emerging services exhibit asymmetric bandwidth requirements. To fill this gap, we study the joint optimization of service placement and request routing in dense MEC networks with multidimensional constraints. We show that this problem generalizes several well-known placement and routing problems and propose an algorithm that achieves close-to-optimal performance using a randomized rounding technique. Evaluation results demonstrate that our approach can effectively utilize available storage, computation, and communication resources to maximize the number of requests served by low-latency edge cloud servers.

Journal ArticleDOI
TL;DR: A Gateway Clustering Energy-Efficient Centroid- (GCEEC-) based routing protocol where cluster head is selected from the centroid position and gateway nodes are selected from each cluster to provide more feasible WSN-based monitoring for temperature, humidity, and illumination in agriculture sector.
Abstract: Wireless sensor networks (WSNs) are becoming one of the demanding platforms, where sensor nodes are sensing and monitoring the physical or environmental conditions and transmit the data to the base station via multihop routing. Agriculture sector also adopted these networks to promote innovations for environmental friendly farming methods, lower the management cost, and achieve scientific cultivation. Due to limited capabilities, the sensor nodes have suffered with energy issues and complex routing processes and lead to data transmission failure and delay in the sensor-based agriculture fields. Due to these limitations, the sensor nodes near the base station are always relaying on it and cause extra burden on base station or going into useless state. To address these issues, this study proposes a Gateway Clustering Energy-Efficient Centroid- (GCEEC-) based routing protocol where cluster head is selected from the centroid position and gateway nodes are selected from each cluster. Gateway node reduces the data load from cluster head nodes and forwards the data towards the base station. Simulation has performed to evaluate the proposed protocol with state-of-the-art protocols. The experimental results indicated the better performance of proposed protocol and provide more feasible WSN-based monitoring for temperature, humidity, and illumination in agriculture sector.

Proceedings Article
01 Jan 2020
TL;DR: Spider is presented, a routing solution that "packetizes" transactions and uses a multi-path transport protocol to achieve high-throughput routing in PCNs, which allows Spider to complete even large transactions on low-capacity payment channels over time.

Journal ArticleDOI
TL;DR: A novel parallelization method of genetic algorithm (GA) solution of the Traveling Salesman Problem (TSP) is presented and the results confirm the efficiency of the proposed method for parallelizing GAs on many-core as well as on multi-core systems.
Abstract: A novel parallelization method of genetic algorithm (GA) solution of the Traveling Salesman Problem (TSP) is presented. The proposed method can considerably accelerate the solution of the equivalent TSP of many complex vehicle routing problems (VRPs) in the cloud implementation of intelligent transportation systems. The solution provides routing information besides all the services required by the autonomous vehicles in vehicular clouds. GA is considered as an important class of evolutionary algorithms that can solve optimization problems in growing intelligent transport systems. But, to meet time criteria in time-constrained problems of intelligent transportation systems like routing and controlling the autonomous vehicles, a highly parallelizable GA is needed. The proposed method parallelizes the GA by designing three concurrent kernels, each of which running some dependent effective operators of GA. It can be straightforwardly adapted to run on many-core and multi-core processors. To best use the valuable resources of such processors in parallel execution of the GA, threads that run any of the triple kernels are synchronized by a low-cost switching mechanism. The proposed method was experimented for parallelizing a GA-based solution of TSP over multi-core and many-core systems. The results confirm the efficiency of the proposed method for parallelizing GAs on many-core as well as on multi-core systems.

Journal ArticleDOI
TL;DR: This paper proposes a Topological change Adaptive Ad hoc On-demand Multipath Distance Vector (TA-AOMDV) routing protocol, which can adapt to high-speed node movement to support quality of service (QoS) in MANET.
Abstract: The mobility and resource limitation of nodes are the critical factors that affect the performance of Mobile AD hoc network (MANET). The mobility of nodes will affect the stability of links, and the limitation of node resources will lead to congestion, so it is very difficult to design a routing protocol that supports quality of service (QoS) in MANET. Especially in the scenario of high-speed node movement, frequent link interruption will damages QoS performance, so it is necessary to design MANET routing protocol that can adapt to network topology changes to support QoS. In this paper, we propose a Topological change Adaptive Ad hoc On-demand Multipath Distance Vector (TA-AOMDV) routing protocol, which can adapt to high-speed node movement to support QoS. In this protocol, a stable path selection algorithm is designed, which not only takes node resources (residual energy, available bandwidth and queue length) as the path selection parameters, but also considers the link stability probability between nodes. Furthermore, in order to adapt to the rapid change of topology, link interrupt prediction mechanism is integrated into the protocol, which updates the routing strategy based on periodic probabilistic estimates of link stability. Different scenarios with node speed in the range of 10-50m/s, data rate in the range of 4-40kbps and number of nodes in the range of 10-100 are simulated on NS2 platform. Our results show that the QoS metrics (packet delivery rate, end-to-end delay, and throughput) of the proposed protocol are significantly improved when the node speed is higher than 30m/s although it is slightly better when the node speed is lower than 30m/s. Our on-demand multipath routing protocol demonstrates high potential to support QoS for high-speed MANET.

Journal ArticleDOI
TL;DR: This survey paper presents a comprehensive review on state-of-the-art routing protocols for UAV-aided VANETs and categorizes them into seven groups in terms of their working mechanism and design principles.
Abstract: In intelligent transportation systems, a vehicular ad hoc network (VANET) has a significant impact in enhancing road safety, traffic management efficiency, and in-vehicle infotainment features. Routing in a VANET is hampered by frequent link disconnection for non-line-of-sight communication due to roadside obstacles, high mobility, and frequent topological changes. With the help of three-dimensional movement capability, an unmanned aerial vehicle (UAV) can drastically improve the routing experience of a VANET, by increasing the line-of-sight probability, better connectivity, and efficient store-carry-forward mechanism. As a result, various routing protocols with different objectives have been reported for UAV-aided VANETs. Several surveys have been conducted based on different routing protocols for VANETs so far. However, to the best of the authors’ knowledge, no survey exists till now that dedicatedly covers routing protocols for UAV-aided VANETs. This survey paper presents a comprehensive review on state-of-the-art routing protocols for UAV-aided VANETs. The protocols are categorized into seven groups in terms of their working mechanism and design principles. The shortcomings of the protocols are identified individually by critically analyzing them with regard to their advantages, disadvantages, application areas, and future improvements. The routing protocols are qualitatively compared with each other in tabular format as well on the basis of various design aspects and system parameters. In particular, not only performance and special features but also optimization criteria and techniques are extensively discussed in addition to the tabular comparison. Furthermore, open research issues and challenges are summarized and discussed.

Journal ArticleDOI
Si Liu1, De-gan Zhang1, Xiao-huan Liu1, Ting Zhang1, Hao Wu1 
TL;DR: An adaptive repair algorithm for TORA routing protocol based on flood control strategy (AR-TORA-FCS) is proposed and results show that the algorithm reduces control overhead, improves the packet delivery rate, and improves average end-to-end delay.

Journal ArticleDOI
TL;DR: This article looks into the details of routing in WSN using different optimization techniques and provides the future insight for researchers to fill in existing gaps in the WSN research field and to find new research trends in this area.
Abstract: Over the past few decades, one of the important advancements in wireless communication is low cost and limited power devices known as wireless sensor networks (WSNs). Sensor nodes are used to transmit data but have limited amount of energy. As the transmission takes place, energy gets depleted. So energy consumption and network lifetime are the major challenges in a WSN. Much research has been done in the past years to determine an optimal path between source and destination nodes, which will result in maximizing energy conservation of a network. However, the challenge is to create a routing algorithm that takes into consideration the major issues of minimizing energy consumption and maximizing network lifetime. Various optimization techniques are available to determine a routing path between a source node and destination node. In this article, we look into the details of routing in WSN using different optimization techniques. This article provides us a comprehensive summary of the previous studies in field of WSN during the span of 2010–2019. The results provided in this article provide the future insight for researchers to fill in existing gaps in the WSN research field and to find new research trends in this area.

Journal ArticleDOI
TL;DR: A novel fuzzy electric vehicle routing problem with time windows and recharging stations (FEVRPTW) is investigated, and a fuzzy optimization model is established based on credibility theory for this problem.
Abstract: As fuel prices increase and emission regulations become increasingly strict, electric vehicles have been used in various logistics distribution activities. Most studies have focused on the electric vehicle routing problem under a deterministic environment, neglecting the effects of uncertain factors in practical logistics distribution. Thus, a novel fuzzy electric vehicle routing problem with time windows and recharging stations (FEVRPTW) is investigated in this study, and a fuzzy optimization model is established based on credibility theory for this problem. In the presented model, fuzzy numbers are used to denote the uncertainties of service time, battery energy consumption, and travel time. Moreover, the partial recharge is allowed under the uncertain environment. To solve the model, an adaptive large neighborhood search (ALNS) algorithm enhanced with the fuzzy simulation method is proposed. In the proposed ALNS algorithm, four new removal algorithms are designed and integrated for addressing the FEVRPTW. To further improve the algorithmic performance, the variable neighborhood descent algorithm is embedded into the proposed ALNS algorithm and five local search operators are applied. The experiments were conducted to verify the effectiveness of the proposed ALNS algorithm for solving the presented model.

Journal ArticleDOI
TL;DR: The proposed architecture consolidates an evolving network standard named as software defined networking in internet of vehicles which enables it to handle highly dynamic networks in an abstract way by dividing the data plane from the control plane.
Abstract: Proposing an optimal routing protocol for internet of vehicles with reduced overhead has endured to be a challenge owing to the incompetence of the current architecture to manage flexibility and scalability. The proposed architecture, therefore, consolidates an evolving network standard named as software defined networking in internet of vehicles. Which enables it to handle highly dynamic networks in an abstract way by dividing the data plane from the control plane. Firstly, road-aware routing strategy is introduced: a performance-enhanced routing protocol designed specifically for infrastructure-assisted vehicular networks. In which roads are divided into road segments, with road side units for multi-hop communication. A unique property of the proposed protocol is that it explores the cellular network to relay control messages to and from the controller with low latency. The concept of edge controller is introduced as an operational backbone of the vehicle grid in internet of vehicles, to have a real-time vehicle topology. Last but not least, a novel mathematical model is estimated which assists primary controller in a way to find not only a shortest but a durable path. The results illustrate the significant performance of the proposed protocol in terms of availability with limited routing overhead. In addition, we also found that edge controller contributes mainly to minimizes the path failure in the network.

Journal ArticleDOI
01 Mar 2020
TL;DR: The proposed algorithm is the first unified algorithm to solve the SMT construction under both octagonal and rectilinear architecture and can obtain several topologies of SMT, which is beneficial for optimizing congestion in VLSI global routing stage.
Abstract: The Steiner minimal tree (SMT) problem is an NP-hard problem, which is the best connection model for a multi-terminal net in global routing problem. This paper presents a unified algorithm for octagonal and rectilinear SMT construction based on hybrid transformation strategy (HTS) and self-adapting particle swarm optimization. Firstly, an effective HTS is proposed to enlarge the search space and improve the convergence speed. Secondly, the proposed HTS in the evolutionary process may produce an ineffective solution, and consequently the crossover and mutation operators of genetic algorithm (GA) based on union-find sets is proposed. Thirdly, a self-adapting strategy that can adjust the acceleration coefficients is proposed to further improve the convergence and the quality of the proposed algorithm. Finally, the hybrid transformation can be applied to GA and the proposed algorithm can be applied to rectilinear architecture. To our best knowledge, the proposed algorithm is the first unified algorithm to solve the SMT construction under both octagonal and rectilinear architecture. The experimental results show that the proposed algorithm can efficiently provide a better solution for SMT problem both in octagonal and rectilinear architectures than others. Moreover, the algorithm can obtain several topologies of SMT, which is beneficial for optimizing congestion in VLSI global routing stage.

Journal ArticleDOI
TL;DR: A novel routing protocol for urban VANETs called RSU-assisted Q-learning-based Traffic-Aware Routing (QTAR) is introduced, combining the advantages of geographic routing with the static road map information, which outperforms the existing traffic-aware routing protocols.
Abstract: In urban vehicular ad hoc networks (VANETs), the high mobility of vehicles along street roads poses daunting challenges to routing protocols and has a great impact on network performance. In addition, the frequent network partition caused by an uneven distribution of vehicles in an urban environment further places higher requirements on the routing protocols in VANETs. More importantly, the high vehicle density during the traffic peak hours and a variety of natural obstacles, such as tall buildings, other vehicles and trees, greatly increase the difficulty of protocol design for high quality communications. Considering these issues, in this paper, we introduce a novel routing protocol for urban VANETs called RSU-assisted Q-learning-based Traffic-Aware Routing (QTAR). Combining the advantages of geographic routing with the static road map information, QTAR learns the road segment traffic information based on the Q-learning algorithm. In QTAR, a routing path consists of multiple dynamically selected high reliability connection road segments that enable packets to reach their destination effectively. For packet forwarding within a road segment, distributed V2V Q-learning (Q-learning occurs between vehicles) integrated with QGGF (Q-greedy geographical forwarding) is adopted to reduce delivery delay and the effect of fast vehicle movements on path sensitivity, while distributed R2R Q-learning (Q-learning occurs between RSU units) is designed for packet forwarding at each intermediate intersection. In the case of a local optimum occurring in QGGF, SCF (store-carry-forward) is used to reduce the possibility of packet loss. Detailed simulation experimental results demonstrate that QTAR outperforms the existing traffic-aware routing protocols, in terms of 7.9% and 16.38% higher average packet delivery ratios than those of reliable traffic-aware routing (RTAR) and greedy traffic-aware routing (GyTAR) in high vehicular density scenarios and 30.96% and 46.19% lower average end-to-end delays with respect to RTAR and GyTAR in low vehicular density scenarios, respectively.

Journal ArticleDOI
TL;DR: This work proposes a BCP solver for a generic model that encompasses a wide class of VRPs and incorporates the key elements found in the best existing VRP algorithms: ng-path relaxation, rank-1 cuts with limited memory, path enumeration, and rounded capacity cuts; all generalized through the new concepts of “packing set’ and “elementarity set”.
Abstract: Major advances were recently obtained in the exact solution of vehicle routing problems (VRPs) Sophisticated branch-cut-and-price (BCP) algorithms for some of the most classical VRP variants now solve many instances with up to a few hundreds of customers However, adapting and reimplementing those successful algorithms for other variants can be a very demanding task This work proposes a BCP solver for a generic model that encompasses a wide class of VRPs It incorporates the key elements found in the best existing VRP algorithms: ng-path relaxation, rank-1 cuts with limited memory, path enumeration, and rounded capacity cuts; all generalized through the new concepts of “packing set” and “elementarity set” The concepts are also used to derive a branching rule based on accumulated resource consumption and to generalize the Ryan and Foster branching rule Extensive experiments on several variants show that the generic solver has an excellent overall performance, in many problems being better than the best specific algorithms Even some non-VRPs, like bin packing, vector packing and generalized assignment, can be modeled and effectively solved

Journal ArticleDOI
TL;DR: Result of systematic review reveals that consumption of energy is the most fundamental issue in WSN however, it is not noticed by the researchers and practitioners where as it can contribute for the improvement of the energy efficiency.
Abstract: In wireless sensor networks (WSN), routing is quite challenging area of research where packets are forwarded through multiple nodes to the base station. The packet being sent over the network should be shared in an energy efficient manner. It also considers the residual power of battery to enhance the network life time. Existing energy efficient routing solutions and surveys are presented but still there is a need for Systematic Literature Review (SLR) to identify the valid problems. This paper performs SLR for energy efficiency routing with 172 papers at initial stage. Next, 50 papers are shortlisted after filtration based on quality valuation and selection criteria by ensuring relevance with energy efficiency. Initially, we present literature that includes schemes for threshold sensitive, adaptive periodic threshold sensitive, power efficient, hybrid energy efficient distribution and low energy adaptive mechanisms. Result of systematic review reveals that consumption of energy is the most fundamental issue in WSN however, is not noticed by the researchers and practitioners where as it can contribute for the improvement of the energy efficiency. It also elaborates the weaknesses of the existing approaches which make them inappropriate for energy efficient routing in WSN.

Journal ArticleDOI
TL;DR: The class where the decision about when the routes start from the depot has to be taken is considered and the related literature is reviewed.
Abstract: In vehicle routing problems (VRPs) the decisions to be taken concern the assignment of customers to vehicles and the sequencing of the customers assigned to each vehicle. Additional decisions may need to be jointly taken, depending on the specific problem setting. In this paper, after discussing the different kinds of decisions taken in different classes of VRPs, the class where the decision about when the routes start from the depot has to be taken is considered and the related literature is reviewed. This class of problems, that we call VRPs over time, includes the periodic routing problems, the inventory routing problems, the vehicle routing problems with release dates, and the multi-trip vehicle routing problems.