Query: peer to peer

title: Bitcoin Proof of Stake: A Peer to Peer Electronic Cash System
abstract: Today, Bitcoin core continues utilizing proof of work, a consensus algorithm that is slow, open to 51% attacks, costly to mine, harmful to the environment, and resistant to scalability. There are, however, many innovations unique to Bitcoin that require preservation, such as its 21 million token supply model and proven code base developed by many of the world's foremost software engineers and cryptographers.

title: Peer to Peer Trading in Electricity Networks: An Overview
abstract: Peer to peer trading is a next generation energy management technique that economically benefits proactive consumers (prosumers) transacting their energy as goods and services. At the same time, peer to peer energy trading is also expected to help the grid by reducing peak demand, lowering reserve requirements, and curtailing network loss. However, large scale deployment of peer to peer trading in electricity networks poses a number of challenges in modeling transactions in both the virtual and physical layers of the network. As such, this article provides a comprehensive review of the state of the art in research on peer to peer energy trading techniques. By doing so, we provide an overview of the key features of peer to peer trading and its benefits of relevance to the grid and prosumers. Then, we systematically classify the existing research in terms of the challenges that the studies address in the virtual and the physical layers. We then further identify and discuss those technical approaches that have been extensively used to address the challenges in peer to peer transactions. Finally, the paper is concluded with potential future research directions.

title: Outsourcing Tasks Online: Matching Supply and Demand on Peer to Peer Internet Platforms
abstract: We study the growth of online peer to peer markets. Using data from TaskRabbit, an expanding marketplace for domestic tasks at the time of our study, we show that growth varies considerably across cities. To disentangle the potential drivers of growth, we look separately at demand and supply imbalances, network effects, and geographic heterogeneity. First, we find that supply is highly elastic: in periods when demand doubles, sellers perform almost twice as many tasks, prices hardly increase, and the probability of requested tasks being matched falls only slightly. The first result implies that in markets where supply can accommodate demand fluctuations, growth relies on attracting buyers at a faster rate than sellers. Second and perhaps most surprisingly, we find no evidence of network effects in matching: doubling the number of buyers and sellers only doubles the number of matches. Third, we show that the cities where market fundamentals promote efficient matching of buyers and sellers are also those that are the fastest growing. This heterogeneity in matching efficiency is related to two measures of market thickness: geographic density (buyers and sellers living close together) and level of task standardization (buyers requesting homogeneous tasks) Our results have two main implications for peer to peer markets in which network effects are limited by the local and time sensitive nature of the services exchanged. First, marketplace growth largely depends on strategic geographic expansion. Second, a competitive rather than winner take all equilibrium may arise in the long run. This paper was accepted by Bruno Cassiman, business strategy.

title: Business Models in the Sharing Economy: Manufacturing Durable Goods in the Presence of Peer to Peer Rental Markets
abstract: Business models that focus on providing access to assets rather than on transferring ownership of goods have become an important industry trend, representing a challenge for incumbent firms. This paper analyzes the interaction of a peer to peer (P2P) rental market and an original equipment manufacturer (OEM) Our analysis highlights the important role of consumer heterogeneity in usage rates as a driving factor of the mechanisms that explain the different market outcomes. Indeed, both the OEM and consumers can benefit from P2P rental markets for intermediate ranges of consumer heterogeneity in usage rates, but both can be worse off when the heterogeneity is too low or too high. Further, P2P rental markets have an equalizing effect on the heterogeneous consumer population, as low usage consumers earn relatively more from P2P rentals than the high usage consumers. We investigate alternative market structures for the OEM, and show that under intermediate levels of consumer heterogeneity in usage rates, it is best for the OEM to operate in the presence of a P2P rental platform. If heterogeneity in usage rates is too low, the OEM prefers to operate as a monopoly, offering sales only, whereas if heterogeneity is too high, the OEM prefers to offer sales and rentals directly to consumers. In addition, if the incumbent firm manages the P2P platform, it would choose to charge a transaction fee equal to zero for P2P rentals. Thus, contrary to what could be expected, the OEM has an incentive to facilitate P2P rentals in a large variety of cases.

title: FedCoin: A Peer to Peer Payment System for Federated Learning
abstract: Federated learning (FL) is an emerging collaborative machine learning method to train models on distributed datasets with privacy concerns. To properly incentivize data owners to contribute their efforts, Shapley Value (SV) is often adopted to fairly assess their contribution. However, the calculation of SV is time consuming and computationally costly. In this paper, we propose FedCoin, a blockchain based peer to peer payment system for FL to enable a feasible SV based profit distribution. In FedCoin, blockchain consensus entities calculate SVs and a new block is created based on the proof of Shapley (PoSap) protocol. It is in contrast to the popular BitCoin network where consensus entities "mine" new blocks by solving meaningless puzzles. Based on the computed SVs, a scheme for dividing the incentive payoffs among FL clients with nonrepudiation and tamper resistance properties is proposed. Experimental results based on real world data show that FedCoin can promote high quality data from FL clients through accurately computing SVs with an upper bound on the computational resources required for reaching consensus. It opens opportunities for non data owners to play a role in FL.

title: Peer to Peer Contact Tracing: Development of a Privacy Preserving Smartphone App
abstract: The novel coronavirus disease 2019 (COVID 19) pandemic is an urgent public health crisis, with epidemiologic models predicting severe consequences, including high death rates, if the virus is permitted to run its course without any intervention or response. Contact tracing using smartphone technology is a powerful tool that may be employed to limit disease transmission during an epidemic or pandemic; yet, contact tracing apps present significant privacy concerns regarding the collection of personal data such as location.  The aim of this study is to develop an effective contact tracing smartphone app that respects user privacy by not collecting location information or other personal data.  We propose the use of an anonymized graph of interpersonal interactions to conduct a novel form of contact tracing and have developed a proof of concept smartphone app that implements this approach. Additionally, we developed a computer simulation model that demonstrates the impact of our proposal on epidemic or pandemic outbreak trajectories across multiple rates of adoption.  Our proof of concept smartphone app allows users to create "checkpoints" for contact tracing, check their risk level based on their past interactions, and anonymously self report a positive status to their peer network. Our simulation results suggest that higher adoption rates of such an app may result in a better controlled epidemic or pandemic outbreak.  Our proposed smartphone based contact tracing method presents a novel solution that preserves privacy while demonstrating the potential to suppress an epidemic or pandemic outbreak. This app could potentially be applied to the current COVID 19 pandemic as well as other epidemics or pandemics in the future to achieve a middle ground between drastic isolation measures and unmitigated disease spread.

title: A Decentralized Bilateral Energy Trading System for Peer to Peer Electricity Markets
abstract: Increase in the deployment of distributed energy resources (DERs) has triggered a new trend to redesign electricity markets as consumer centric markets relying on peer to peer (P2P) approaches. In the P2P markets, players can directly negotiate under bilateral energy trading to match demand and supply. The trading scheme should be designed adequately to incentivise players to participate in the trading process actively. This article proposes a decentralized P2P energy trading scheme for electricity markets with high penetration of DERs. A novel algorithm using primal dual gradient method is described to clear the market in a fully decentralized manner without interaction of any central entity. Also, to incorporate technical constraints in the energy trading, line flow constraints are modeled in the bilateral energy trading to avoid overloaded or congested lines in the system. This market structure respects market players' preferences by allowing bilateral energy trading with product differentiation. The performance of the proposed method is evaluated using simulation studies, and it is found that market players can trade energy to maximize their welfare without violating line flow constraints. Also, compared with other similar methods for P2P trading, the proposed approach needs lower data exchange and has a faster convergence.

title: Co simulation of electricity distribution networks and peer to peer energy trading platforms
abstract: There has been significant recent interest in local electricity trading platforms, and particularly in the application of distributed ledger and blockchain technology for distributed, or peer to peer energy trading in local energy communities. Several projects worldwide have demonstrated this concept on a small scale in Low Voltage (LV) distribution networks and microgrids. However, previous work in this area has not sufficiently addressed the potential impacts of peer to peer energy trading and other local electricity trading mechanisms on the control, operation and planning of the electricity distribution networks. Accordingly, this paper presents a methodology for the co simulation of power distribution networks and local peer to peer energy trading platforms. The distribution system simulator is interfaced with a peer to peer energy trading platform, which employs a blockchain based distributed double auction trade mechanism. The presented co simulation approach is demonstrated using a case study of typical European suburban distribution network. It is demonstrated in the paper that this approach can be used to analyse the impacts of peer to peer energy trading on network operational performance. The analysis presented in the paper suggests that a moderate level of peer to peer trading does not have significant impacts on network operational performance.

title: Peer to Peer Electricity Market Analysis: From Variational to Generalized Nash Equilibrium
abstract: We consider a network of prosumers involved in peer to peer energy exchanges, with differentiation price preferences on the trades with their neighbors, and we analyze two market designs: (i) a centralized market, used as a benchmark, where a global market operator optimizes the flows (trades) between the nodes, local demand and exibility activation to maximize the system overall social welfare; (ii) a distributed peer to peer market design where prosumers in local energy communities optimize selfishly their trades, demand, and exibility activation. We first characterize the solution of the peer to peer market as a Variational Equilibrium and prove that the set of Variational Equilibria coincides with the set of social welfare optimal solutions of market design (i) We give several results that help understanding the structure of the trades at an equilibrium or at the optimum. We characterize the impact of preferences on the network line congestion and renewable energy surplus under both designs. We provide a reduced example for which we give the set of all possible generalized equilibria, which enables to give an approximation of the price of anarchy. We provide a more realistic example which relies on the IEEE 14 bus network, for which we can simulate the trades under di erent preference prices. Our analysis shows in particular that the preferences have a large impact on the structure of the trades, but that one equilibrium (variational) is optimal. Finally, the learning mechanism needed to reach an equilibrium state in the peer to peer market design is discussed together with privacy issues.

title: Grid Influenced Peer to Peer Energy Trading
abstract: This paper proposes a peer to peer (P2P) energy trading scheme that can help a centralized power system to reduce the total electricity demand of its customers at the peak hour. To do so, a cooperative Stackelberg game is formulated, in which the centralized power system acts as the leader that needs to decide on a price at the peak demand period to incentivize prosumers to not seek any energy from it. The prosumers, on the other hand, act as followers and respond to the leader's decision by forming suitable coalitions with neighboring prosumers in order to participate in P2P energy trading to meet their energy demand. The properties of the proposed Stackelberg game are studied. It is shown that the game has a unique and stable Stackelberg equilibrium, as a result of the stability of prosumers' coalitions. At the equilibrium, the leader chooses its strategy using a derived closed form expression, while the prosumers choose their equilibrium coalition structure. An algorithm is proposed that enables the centralized power system and the prosumers to reach the equilibrium solution. Numerical case studies demonstrate the beneficial properties of the proposed scheme.