Billions of Internet of Things (IoT) devices deployed today collect massive amounts of potentially valuable data. To efficiently utilize this data, markets must be developed where data can be traded in real time. Blockchain technology offers a potential platform for these types of markets. However, previous proposals using blockchain technology either require trusted third parties such as data brokers, or necessitate a large number of on-chain transactions to operate, incurring excessive overhead costs. This paper proposes a trustless data trading system that minimizes both the risk of fraud and the number of transactions performed on chain. In this system, data producers and consumers come to binding agreements while trading data off chain and they only settle on chain when a deposit or withdrawal of funds is required. A credit mechanism is also developed to further reduce the incurred fees. Additionally, the proposed marketplace is benchmarked on a private Ethereum network running on a lab-scale testbed and the proposed credit system is simulated so to analyze its risks and benefits.

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Modern vehicles rely on data from a vast array of sensors such as radar and GPS equipment that can be shared with surrounding vehicles and other interested parties. Vehicle-to-everything (V2X) is the collection of systems that enable such communication. Although this data sharing has the potential to improve both the safety and efficiency of vehicles, ensuring that what is shared has not been altered, deleted, forged, leaked, or otherwise tampered with remains a challenging problem. Today, blockchain technology allows a system's participants to come to an agreement (consensus) on the state of the system and its data in a decentralized, trustless manner. This new technology may be capable of securing V2X data, as well as enabling other useful V2X services such as payments. However, the V2X ecosystem poses several unique challenges that complicate the application of blockchain technology, not least of which is the vast number of communications that any proposed blockchain network will need to support. This paper gives an overview of V2X and blockchain technology, explores potential applications of blockchain within the V2X domain, and justifies its importance. It also reviews, analyzes, and discusses various blockchain architectures that could support V2X applications. Though there is a place for blockchain in the V2X environment, currently there is no robust or mature blockchain architecture available that could support the entire ecosystem's needs. As such, this paper proposes novel directions for future research towards the creation of such a blockchain.

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In earlier technology nodes, FPGAs had low power consumption compared to other compute chips such as CPUs and GPUs. However, in the 14nm technology node, FPGAs are consuming unprecedented power in the 100+W range, making power consumption a pressing concern. To reduce FPGA power consumption, several researchers have proposed deploying dynamic voltage scaling. While the previously proposed solutions show promising results, they have difficulty guaranteeing safe operation at reduced voltages for applications that use the FPGA hard blocks. In this work, we present the first DVS solution that is able to fully handle FPGA applications that use BRAMs. Our solution not only robustly tests the soft logic component of the application but also tests all components connected to the BRAMs. We extend a previously proposed CAD tool, FRoC, to automatically generate calibration bitstreams that are used to measure the application’s critical path delays on silicon. The calibration bitstreams also include testers that ensure all used SRAM cells operate safely while scaling V dd . We experimentally show that using our DVS solution we can save 32% of the total power consumed by a discrete Fourier transform application running with the fixed nominal supply voltage and clocked at the F max reported by static timing analysis.