162 research outputs found
Transaction Propagation on Permissionless Blockchains: Incentive and Routing Mechanisms
Existing permissionless blockchain solutions rely on peer-to-peer propagation
mechanisms, where nodes in a network transfer transaction they received to
their neighbors. Unfortunately, there is no explicit incentive for such
transaction propagation. Therefore, existing propagation mechanisms will not be
sustainable in a fully decentralized blockchain with rational nodes. In this
work, we formally define the problem of incentivizing nodes for transaction
propagation. We propose an incentive mechanism where each node involved in the
propagation of a transaction receives a share of the transaction fee. We also
show that our proposal is Sybil-proof. Furthermore, we combine the incentive
mechanism with smart routing to reduce the communication and storage costs at
the same time. The proposed routing mechanism reduces the redundant transaction
propagation from the size of the network to a factor of average shortest path
length. The routing mechanism is built upon a specific type of consensus
protocol where the round leader who creates the transaction block is known in
advance. Note that our routing mechanism is a generic one and can be adopted
independently from the incentive mechanism.Comment: 2018 Crypto Valley Conference on Blockchain Technolog
Compute-and-forward on a line network with random access
Signal superposition and broadcast are important features of the wireless medium. Compute-and-Forward, also known as Physical Layer Network Coding (PLNC), is a technique exploiting these features in order to improve performance of wireless networks. More precisely, it allows wireless terminals to reliably de- code a linear combination of all messages, when a superposition of the messages is received through the physical medium.\ud
In this paper, we propose a random PLNC scheme for a local interference line network in which nodes perform random access scheduling. We prove that our PLNC scheme is capacity achieving in the case of one symmetric bi-directional session with terminals on both ends of this line network model. We demonstrate that our scheme significantly outperforms any other scheme. In particular, by eligibly choosing the access rate of the random access scheduling mechanism for the network, the throughput of our PLNC scheme is at least 3.4 and 1.7 times better than traditional routing and plain network coding, respectively
On the energy benefit of compute-and-forward on the hexagonal lattice
We study the energy benefit of applying compute-and-forward on a wireless hexagonal lattice network with multiple unicast sessions with a specific session placement. Two compute-and-forward based transmission schemes are proposed, which allow the relays to exploit both the broadcast and superposition nature of the wireless network. The energy consumption of both transmission and reception of the nodes are taken into account. We show that with our schemes, the total energy consumption of the network is significantly reduced compared to traditional routing based transmission schemes. Moreover, our schemes also outperform the plain network coding based transmission scheme in terms of power saving as long as the receive energy of the devices is not negligible
Adaptive Active Anti-vibration Control for a Three-dimensional Helicopter Flexible Slung-load System with Input Saturations and Backlash
This study investigates active anti-vibration control for a three-dimensional helicopter flexible slung-load system (HFSLS) subject to input saturations and backlash. The first target of the study is to establish a model for a three-dimensional HFSLS. The second target is to develop an adaptive control law for a HFSLS by analyzing its ability to compensate for the effects of input saturations, input backlash, and external disturbances, while achieving the goal of vibration reduction. Simulation results of the numerical show that the proposed adaptive active control technology is effective in solving the oscillation suppression problem for the three-dimensional HFSLS with input saturations and backlash.</p
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