scholarly journals MILP, Pseudo-Boolean, and OMT Solvers for Optimal Fault-Tolerant Placements of Relay Nodes in Mission Critical Wireless Networks*

2020 ◽  
Vol 174 (3-4) ◽  
pp. 229-258
Author(s):  
Qian Matteo Chen ◽  
Alberto Finzi ◽  
Toni Mancini ◽  
Igor Melatti ◽  
Enrico Tronci
Keyword(s):  
Fault Tolerance ◽  
Communication Networks ◽  
Electromagnetic Interference ◽  
Fault Tolerant ◽  
Relay Node ◽  
Problem Formulation ◽  
Leonardo Da Vinci ◽  
Radio Communication ◽  
Relay Nodes ◽  
Mission Critical

In critical infrastructures like airports, much care has to be devoted in protecting radio communication networks from external electromagnetic interference. Protection of such mission-critical radio communication networks is usually tackled by exploiting radiogoniometers: at least three suitably deployed radiogoniometers, and a gateway gathering information from them, permit to monitor and localise sources of electromagnetic emissions that are not supposed to be present in the monitored area. Typically, radiogoniometers are connected to the gateway through relay nodes. As a result, some degree of fault-tolerance for the network of relay nodes is essential in order to offer a reliable monitoring. On the other hand, deployment of relay nodes is typically quite expensive. As a result, we have two conflicting requirements: minimise costs while guaranteeing a given fault-tolerance. In this paper, we address the problem of computing a deployment for relay nodes that minimises the overall cost while at the same time guaranteeing proper working of the network even when some of the relay nodes (up to a given maximum number) become faulty (fault-tolerance). We show that, by means of a computation-intensive pre-processing on a HPC infrastructure, the above optimisation problem can be encoded as a 0/1 Linear Program, becoming suitable to be approached with standard Artificial Intelligence reasoners like MILP, PB-SAT, and SMT/OMT solvers. Our problem formulation enables us to present experimental results comparing the performance of these three solving technologies on a real case study of a relay node network deployment in areas of the Leonardo da Vinci Airport in Rome, Italy.

Efficient Fault Tolerance on Cloud Environments

2018 ◽  
Vol 8 (3) ◽  
pp. 20-31 ◽  
Author(s):  
Sam Goundar ◽  
Akashdeep Bhardwaj
Keyword(s):  
Fault Tolerance ◽  
Web Applications ◽  
Fault Tolerant ◽  
Cloud Services ◽  
Level Of Service ◽  
Cloud Environments ◽  
Computing Environments ◽  
Service Assurance ◽  
Mission Critical ◽  
The Impact

With mission critical web applications and resources being hosted on cloud environments, and cloud services growing fast, the need for having greater level of service assurance regarding fault tolerance for availability and reliability has increased. The high priority now is ensuring a fault tolerant environment that can keep the systems up and running. To minimize the impact of downtime or accessibility failure due to systems, network devices or hardware, the expectations are that such failures need to be anticipated and handled proactively in fast, intelligent way. This article discusses the fault tolerance system for cloud computing environments, analyzes whether this is effective for Cloud environments.

Consistency Is Not Enough in Byzantine Fault Tolerance

2018 ◽  
pp. 1238-1247
Author(s):  
Wenbing Zhao
Keyword(s):  
Fault Tolerance ◽  
Fault Tolerant ◽  
Large Body ◽  
Random Numbers ◽  
Security Requirement ◽  
Critical Systems ◽  
Byzantine Fault Tolerance ◽  
Byzantine Fault ◽  
Mission Critical ◽  
Fault Tolerant Systems

The use of good random numbers is crucial to the security of many mission-critical systems. However, when such systems are replicated for Byzantine fault tolerance, a serious issue arises, i.e., how do we preserve the integrity of the systems while ensuring strong replica consistency? Despite the fact that there exists a large body of work on how to render replicas deterministic under the benign fault model, the solutions regarding the random number control are often overly simplistic without regard to the security requirement, and hence, they are not suitable for practical Byzantine fault tolerance. In this chapter, we present a novel integrity-preserving replica coordination algorithm for Byzantine fault tolerant systems. The central idea behind our CD-BFT algorithm is that all random numbers to be used by the replicas are collectively determined, based on the contributions made by a quorum of replicas, at least f+1 of which are not faulty.

HWN* Framework Towards 4G Mobile Communication Networks

2010 ◽  
pp. 100-124
Author(s):  
Chong Shen ◽  
Dirk Pesch ◽  
Robert Atkinson ◽  
Wencai Du
Keyword(s):  
Wireless Network ◽  
Communication Networks ◽  
Resource Sharing ◽  
Relay Node ◽  
System Capacity ◽  
Spatial Reuse ◽  
Medium Access ◽  
Relay Nodes ◽  
Radio Access ◽  
Hybrid Wireless Network

The objective of the Hybrid Wireless Network with dedicated Relay Nodes (HWN*) proposal is to interface the Base Station (BS) Oriented Mobile Network (BSON) and the 802.11X assisted Mobile Ad hoc Wireless Network (MANET) so that one system can be utilised as an alternative radio access network for data transmissions, while the incorporation of the Relay Node (RN) is to extend the communication coverage, optimise medium resource sharing, increase spatial reuse opportunity, stabilise MANET link and create more micro-cells. The HWN* keeps the existing cellular infrastructure and a end-user Mobile Terminal (MT) can borrow radio resources from other cells through secured multi-hop RN relaying, where RNs are placed at pre-engineered locations. The main contribution of this work is the development of a HWN* system framework and related medium access and routing protocols/algorithms. The framework dedicatedly addresses the transparent multiple interface traffic handover management, cross layer routing, RN positioning and network topology issues to increase communication system capacity, improve Quality of Service (QoS), optimise transmission delay and reduce packet delivery delay.

Efficient Fault Tolerance on Cloud Environments

2021 ◽  
pp. 1231-1243
Author(s):  
Sam Goundar ◽  
Akashdeep Bhardwaj
Keyword(s):  
Cloud Computing ◽  
Fault Tolerance ◽  
Web Applications ◽  
Fault Tolerant ◽  
Cloud Services ◽  
Cloud Environments ◽  
Computing Environments ◽  
Service Assurance ◽  
Mission Critical ◽  
The Impact

With mission critical web applications and resources being hosted on cloud environments, and cloud services growing fast, the need for having greater level of service assurance regarding fault tolerance for availability and reliability has increased. The high priority now is ensuring a fault tolerant environment that can keep the systems up and running. To minimize the impact of downtime or accessibility failure due to systems, network devices or hardware, the expectations are that such failures need to be anticipated and handled proactively in fast, intelligent way. This article discusses the fault tolerance system for cloud computing environments, analyzes whether this is effective for Cloud environments.

Consistency Is Not Enough in Byzantine Fault Tolerance

2019 ◽  
pp. 88-99
Author(s):  
Wenbing Zhao
Keyword(s):  
Fault Tolerance ◽  
Fault Tolerant ◽  
Large Body ◽  
Random Numbers ◽  
Security Requirement ◽  
Critical Systems ◽  
Byzantine Fault Tolerance ◽  
Byzantine Fault ◽  
Mission Critical ◽  
Fault Tolerant Systems

The use of good random numbers is crucial to the security of many mission-critical systems. However, when such systems are replicated for Byzantine fault tolerance, a serious issue arises (i.e., how do we preserve the integrity of the systems while ensuring strong replica consistency?). Despite the fact that there exists a large body of work on how to render replicas deterministic under the benign fault model, the solutions regarding the random number control are often overly simplistic without regard to the security requirement, and hence, they are not suitable for practical Byzantine fault tolerance. In this chapter, the authors present a novel integrity-preserving replica coordination algorithm for Byzantine fault tolerant systems. The central idea behind our CD-BFT algorithm is that all random numbers to be used by the replicas are collectively determined, based on the contributions made by a quorum of replicas, at least f+1 of which are not faulty.

Analysis of relay node failure in heterogeneous wireless sensor networks

2020 ◽  
Vol 13 ◽  
Author(s):  
Gholamreza Kakamanshadi ◽  
Savita Gupta ◽  
Sukhwinder Singh
Keyword(s):  
Wireless Sensor Networks ◽  
Fault Tolerance ◽  
Sensor Networks ◽  
Relay Node ◽  
Network Size ◽  
Wireless Sensor ◽  
Time To Failure ◽  
Relay Nodes ◽  
Tolerance Level ◽  
Heterogeneous Wireless Sensor Networks

Introduction: Fault tolerance is an important issue for assuring data reliability, energy saving and prolonging the lifetime of wireless sensor networks. Since, sensor node, relay node, etc. are prone to failure, there is a need an effective fault tolerance mechanism. Method: Relay nodes have used as cluster heads and the concept of two disjoint paths has used for proving fault tolerance against link failure. To evaluate the Fault Tolerance Level, Mean Time to Failure and subsequently Failure Rate has calculated, that reflect the reliability of the network. Results: The results show that as the area size of the network increases, the average Fault Tolerance Level of the network almost becomes constant. Furthermore, when the Mean Time to Failure of the network decreases then the Failure Rate increases. It means the overall reliability of the network with smaller network size is more than the larger network size. Conclusion: This analysis helps the network designers to decide the quantity of deployment of relay nodes with respect to fault tolerance level. It also, may help to prevent relay nodes failure as to take appropriate action so as to increase the fault tolerance level of the network as well as network reliability. Discussion: This paper presents a detailed analysis of relay nodes failure under distinct network configurations in heterogeneous wireless sensor networks.

scholarly journals Interactive Placemaking - Prototype of an Intelligent Urban Building Infrastructure for Critical Borderlands / Kinmen

2018 ◽  
Vol 12 (7) ◽  
pp. 128
Author(s):  
Li-Yen Hsu
Keyword(s):  
Artificial Intelligence ◽  
Fault Tolerance ◽  
Communication Networks ◽  
Rural Areas ◽  
Electromagnetic Interference ◽  
Short Range ◽  
Spider Web ◽  
Dedicated Short Range Communication ◽  
Sensor Information ◽  
Hub Airport

Dependable capabilities to counter wicked tasks are proactively needed for borderland placemaking. Initiated recently, in Xiamen, a hub airport is being constructed at Xiangan district’s Dadeng islet, which was taken after the inner war from the outlying borderland of Taiwan - Kinmen. To promote current interactive urbanizing, holistic pervasiveness, and/or resource chaining, a sensor-information infrastructure with availability, reliability, and maintainability features through artificial intelligence -i.e., the plural surveillances, similar in sensing through creatures’ eyes, ears, and nostrils- is prototyped. By plural detection along traffic paths, such dedicated short-range communication networks, evidenced with terrorist uncertainty, can help promote trust, inclusive accessibility, mobile services, and interactive measures, with fault tolerance, Hamiltonian (a mathematical order), connectivity, scalability, electromagnetic interference countering, and reliable accuracy. More flexibility can be justified for the emerging pervasive logistic and security management demand by further applying other network types. The cube-connected cycle is prototyped for the probe application along waterways and in rural areas. The prototyped spider-web network can be resiliently integrated with shorelines and interior paths and configured together into a featured urban building context, radial-ring, whose sustainability is culturally resonated in world heritage, neighboring Tulous; help promote peace developing and evoke economic interactions, globally.

Research on Fault-Tolerant Relay Node Placement Based on Greedy Optimization Algorithm in Wireless Sensor Networks

2011 ◽  
Vol 204-210 ◽  
pp. 1000-1004
Author(s):  
Zhu Wang ◽  
Qi Wang ◽  
De Bao Wei
Keyword(s):  
Optimization Algorithm ◽  
Fault Tolerant ◽  
Relay Node ◽  
Relay Node Placement ◽  
Relay Nodes ◽  
Evaluation Standard ◽  
Node Placement ◽  
Communication Capacity ◽  
Placement Algorithm ◽  
Greedy Optimization

In this paper, relay node’s communication capacity was introduced into the existing model of relay node placement. And we presented a new evaluation standard based on the minimum distance factor of communication network. A new relay node placement algorithm was implemented in solutions, and the algorithm was based on greedy optimization algorithm. The simulation result demonstrates that the algorithm can limit the communication capacity of relay nodes conveniently. Compared with other placement algorithms, improvement of energy-efficiencies in this algorithm is obvious.

Fault Tolerant Guidance of Under-Actuated Satellite Formation Flying Using Inter-Vehicle Coulomb Force

2019 ◽  
Vol 2 (1) ◽  
pp. 43-52
Author(s):  
Alireza Alikhani ◽  
Safa Dehghan M ◽  
Iman Shafieenejad
Keyword(s):  
Fault Tolerance ◽  
Formation Flying ◽  
Fault Tolerant ◽  
Coulomb Force ◽  
Control Law ◽  
Triangular Form ◽  
Satellite Formation Flying ◽  
Satellite Formation ◽  
Guidance Law ◽  
Tolerance Approach

In this study, satellite formation flying guidance in the presence of under actuation using inter-vehicle Coulomb force is investigated. The Coulomb forces are used to stabilize the formation flying mission. For this purpose, the charge of satellites is determined to create appropriate attraction and repulsion and also, to maintain the distance between satellites. Static Coulomb formation of satellites equations including three satellites in triangular form was developed. Furthermore, the charge value of the Coulomb propulsion system required for such formation was obtained. Considering Under actuation of one of the formation satellites, the fault-tolerance approach is proposed for achieving mission goals. Following this approach, in the first step fault-tolerant guidance law is designed. Accordingly, the obtained results show stationary formation. In the next step, tomaintain the formation shape and dimension, a fault-tolerant control law is designed.

Fault Tolerant Reliable Protocol (FTRP) Performance Evaluation in Wireless Sensor Networks: An Extensitive Study

2019 ◽  
pp. 1-36
Keyword(s):  
Wireless Sensor Networks ◽  
Fault Tolerance ◽  
Sensor Networks ◽  
Fault Tolerant ◽  
Cluster Head ◽  
Biological Data ◽  
Wireless Sensor ◽  
Delivery Ratio ◽  
Good Performer ◽  
Wide Range

Fault Tolerant Reliable Protocol (FTRP) is proposed as a novel routing protocol designed for Wireless Sensor Networks (WSNs). FTRP offers fault tolerance reliability for packet exchange and support for dynamic network changes. The key concept used is the use of node logical clustering. The protocol delegates the routing ownership to the cluster heads where fault tolerance functionality is implemented. FTRP utilizes cluster head nodes along with cluster head groups to store packets in transient. In addition, FTRP utilizes broadcast, which reduces the message overhead as compared to classical flooding mechanisms. FTRP manipulates Time to Live values for the various routing messages to control message broadcast. FTRP utilizes jitter in messages transmission to reduce the effect of synchronized node states, which in turn reduces collisions. FTRP performance has been extensively through simulations against Ad-hoc On-demand Distance Vector (AODV) and Optimized Link State (OLSR) routing protocols. Packet Delivery Ratio (PDR), Aggregate Throughput and End-to-End delay (E-2-E) had been used as performance metrics. In terms of PDR and aggregate throughput, it is found that FTRP is an excellent performer in all mobility scenarios whether the network is sparse or dense. In stationary scenarios, FTRP performed well in sparse network; however, in dense network FTRP’s performance had degraded yet in an acceptable range. This degradation is attributed to synchronized nodes states. Reliably delivering a message comes to a cost, as in terms of E-2-E. results show that FTRP is considered a good performer in all mobility scenarios where the network is sparse. In sparse stationary scenario, FTRP is considered good performer, however in dense stationary scenarios FTRP’s E-2-E is not acceptable. There are times when receiving a network message is more important than other costs such as energy or delay. That makes FTRP suitable for wide range of WSNs applications, such as military applications by monitoring soldiers’ biological data and supplies while in battlefield and battle damage assessment. FTRP can also be used in health applications in addition to wide range of geo-fencing, environmental monitoring, resource monitoring, production lines monitoring, agriculture and animals tracking. FTRP should be avoided in dense stationary deployments such as, but not limited to, scenarios where high application response is critical and life endangering such as biohazards detection or within intensive care units.

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