Algorand is a truly decentralized, new, and secure way to manage a shared ledger. Unlike prior approaches based on {\em proof of work}, it requires a negligible amount of computation, and generates a transaction history that does not fork with overwhelmingly high probability. This approach cryptographically selects ---in a way that is provably immune from manipulations, unpredictable until the last minute, but ultimately universally clear--- a set of verifiers in charge of constructing a block of valid transactions. This approach applies to any way of implementing a shared ledger via a tamper-proof sequence of blocks, including traditional blockchains. This paper also presents more efficient alternatives to blockchains, which may be of independent interest.
Algorand significantly enhances all applications based on a public ledger: payments, smart contracts, stock settlement, etc. But, for concreteness, we shall describe it only as a money platform.
Cherrelle Eid, Paul Codani, Yannick Pérez, Javier Reneses · 5 authors
In many electric systems worldwide the penetration of Distributed Energy Resources (DER) at the distribution levels is increasing. This penetration brings in different challenges for electricity system management; however if the flexibility of those DER is well managed opportunities arise for coordination. At high voltage levels under responsibility of the system operator, trading mechanisms like contracts for ancillary services and balancing markets provide opportunities for economic efficient supply of system flexibility services. In a situation with smart metering and real-time management of distribution networks, similar arrangements could be enabled for medium- and low-voltage levels. This paper presents a review and classification of existing DER as flexibility providers and a breakdown of trading platforms for DER flexibility in electricity markets.
BACKGROUND: In 2013, around 40 % of the schools in Sweden had structured programs to prevent tobacco and alcohol debut in compulsory school. There has unfortunately been a lack of scientific evidence to support most of the prevention methods focusing on primary prevention in schools in Sweden. The aim and purpose of the present study is to evaluate the effectiveness of the Non-Governmental Organization SMART contract-signing strategy in reducing the growth of youth substance use and other problem behaviors amongst Swedish adolescents. METHODS: Students from five schools in a medium-sized Swedish municipality were surveyed in three waves from 7(th) to 9(th) grade of compulsory school. We used General Linear Model (GLM) repeated-measures ANOVA to test if the outcome measures smoking, use of snus and alcohol, drunkenness, delinquency, and bullying significantly changed different amounts over time in groups that had participated in the SMART program for long time, a short time, sporadically- or not at all. Groups were compared on demographic background variables, and outcome measures were assessed on all measurement occasions by a one-way ANOVA. The magnitude of group differences at the end of the study was estimated according to Cohen's d. RESULTS: Number of years with a contract has an effect on the levels of self-reported youth problems in 9(th) grade. We found small to medium-sized differences in measured outcomes between students who participated in the program for the longest period of time, 5 years, and who participated for the shortest time, 0-2 years. CONCLUSION: Findings suggests that the SMART program has preventive effects on adolescent substance use.
Luke Anderson, Ralph Holz, Alexander Ponomarev, Paul Rimba · 5 authors
Half a decade after Bitcoin became the first widely used cryptocurrency, blockchains are receiving considerable interest from industry and the research community. Modern blockchains feature services such as name registration and smart contracts. Some employ new forms of consensus, such as proof-of-stake instead of proof-of-work. However, these blockchains are so far relatively poorly investigated, despite the fact that they move considerable assets. In this paper, we explore three representative, modern blockchains---Ethereum, Namecoin, and Peercoin. Our focus is on the features that set them apart from the pure currency use case of Bitcoin. We investigate the blockchains' activity in terms of transactions and usage patterns, identifying some curiosities in the process. For Ethereum, we are mostly interested in the smart contract functionality it offers. We also carry out a brief analysis of issues that are introduced by negligent design of smart contracts. In the case of Namecoin, our focus is how the name registration is used and has developed over time. For Peercoin, we are interested in the use of proof-of-stake, as this consensus algorithm is poorly understood yet used to move considerable value. Finally, we relate the above to the fundamental characteristics of the underlying peer-to-peer networks. We present a crawler for Ethereum and give statistics on the network size. For Peercoin and Namecoin, we identify the relatively small size of the networks and the weak bootstrapping process.
Nicolas Gensollen, Vincent Gauthier, Monique Becker, Michel Marot
In the context of the smart grid, we propose in this paper an algorithm that forms coalitions of agents, called prosumers, that both produce and consume. It is designed to be used by aggregators that aim at selling aggregated surplus of production of the prosumers they control. We rely on real weather data sampled across stations of a given territory in order to simulate realistic production and consumption patterns for each prosumer. This enables us to capture geographical correlations among the agents while preserving the diversity due to different behaviors. As aggregators are bound to the market operator by a contract, they seek to maximize their offer while minimizing their risk. The proposed graph-based algorithm takes the underlying correlation structure of the agents into account and outputs coalitions with both high productivity and low variability. We show that the resulting diversified coalitions are able to generate higher benefits on a constrained energy market, and are more resilient to random failures of the agents.
Most popular blockchain solutions, like Bitcoin, rely on proof-of-work, guaranteeing that the output of the consensus is agreed upon with high probability. However, this probability depends on the delivery of messages and that the computational power of the system is sufficiently scattered among pools of nodes in the network so that no pool can mine more blocks faster than the crowd. New approaches, like Ethereum, generalise the proof-of-work approach by letting individuals deploy their own private blockchain with high transaction throughput. As companies are starting to deploy private chains, it has become crucial to better understand the guarantees blockchains offer in such a small and controlled environment. In this paper, we present the \emph{Blockchain Anomaly}, an execution that we experienced when building our private chain at NICTA/Data61. Even though this anomaly has never been acknowledged before, it may translate into dramatic consequences for the user of blockchains. Named after the infamous Paxos anomaly, this anomaly makes dependent transactions, like "Bob sends money to Carole after he received money from Alice" impossible. This anomaly relies on the fact that existing blockchains do not ensure consensus safety deterministically: there is no way for Bob to make sure that Alice actually sent him coins without Bob using an external mechanism, like converting these coins into a fiat currency that allows him to withdraw. We also explore smart contracts as a potential alternative to transactions in order to freeze coins, and show implementations of smart contract that can suffer from the Blockchain anomaly and others that may cope with it.
This paper analyses the heterogeneity of household consumer preferences for electricity service contracts in a smart grid context. Platform pricing strategies that could incentivise consumers to participate in a two-sided electricity platform market are discussed. The research is based on original data from a discrete choice experiment on electricity service contracts that was conducted with 1,892 electricity consumers in Great Britain in 2015. We estimate a flexible mixed logit model in willingness to pay space and exploit the results in posterior analysis. The findings suggest that while consumers are willing to pay for technical support services, they are likely to demand significant compensation to share their usage and personally identifying data and to participate in automated demand response programs involving remote monitoring and control of electricity usage. Cross-subsidisation of consumers combining appropriate participation payments with sharing of bill savings could incentivise participation of the number of consumers required to provide the optimal level of demand response. We also examine the preference heterogeneity to suggest how, by targeting customers with specific characteristics, smart electricity service providers could significantly reduce their customer acquisition costs.
The Internet of Things and Services (IoTS) has encouraged the development of service provisioning systems in respect to Smart City topics. Most of them are operated as heterogeneous systems which limits end customers’ access and contradicts with IoTS principles. In this paper, we discuss and develop a reference model of an interconnected service marketplace ecosystem. The prototypical implementation incorporates findings from an empirical study and lessons learned from research projects. The elaborated ecosystem enables service request roaming between different parties across system boundaries. The paper presents a feasible centralized architecture, introduces involved parties and parts of a developed message protocol. Why a contracting mechanism is indispensable for request roaming is also outlined. The model’s feasibility is demonstrated by means of a current electric mobility use case: providing access to foreign charging infrastructure without multiple registrations. This work contributes to simplify the data exchange between service platforms to improve Smart City solutions and to support travelers with intelligent mobility applications.
By Riikka Koulu. As cross-border online transactions increase the issue of cross-border dispute resolution and enforcement becomes more and more topical. Disputes arising from e-commerce are seldom taken into the public courts and therefore online dispute resolution (ODR) is becoming a mainstream solution for resolving them. Simultaneously, different applications and possibilities of blockchain technologies such as cryptocurrencies have caught the attention of both computer scientists and legal scholars, increasingly gaining momentum. However, the potential of blockchains reach further than their use as a currency: they can be used for the decentralised execution of programmable contracts known as smart contracts, completely without the need for intermediaries like e-commerce sites, credit card companies or courts. These possibilities have not previously been discussed in relation to dispute resolution. This article provides an introduction to this new technological possibility by examining self-executing smart contracts that utilise novel blockchain technologies. To demonstrate the logic behind smart contracts more concretely, a weather bet (i.e. a bet on what the weather is going to be in a given location) is translated into a programmable smart contract and then discussed in lines of code with further explanations. In addition to this, the author suggests that smart contracts could also be employed for the purposes of dispute resolution, which might provide a solution for the problem of enforcing ODR decisions. Instead of normative analysis, the article provides an introductory analysis of the legal implications that the blockchain technology has outside its application as virtual currency.
This paper presents a comprehensive framework for the assessment of reliability and risk implications of post-fault Demand Response (DR) to provide capacity release in smart distribution networks. A direct load control (DLC) scheme is presented to efficiently disconnect DR customers with differentiated reliability levels. The cost of interrupted load is used as a proxy for the value of the differentiated reliability contracts for different customers to prioritize the disconnections. The framework tackles current distribution system operator (DSO)’s corrective actions such as network reconfiguration, emergency ratings and load shedding, also considering the physical payback effects from the DR customers’ reconnection. Sequential Monte Carlo simulation (SMCS) is used to quantify the risk borne by the DSO if contracting fewer DR customers than required by deterministic security standards. Numerical results demonstrate the benefits of the proposed DR scheme, when compared to the current DLC scheme applied from the local DSO. In addition, as a key point to boost the commercial implementation of such DR schemes, the results show how the required DR volume could be much lower than initially estimated when properly accounting for the actual risk of interruptions and for the possibility of deploying the asset emergency ratings. The findings of this work support the rationale of moving from the current prescriptive deterministic security standards to a probabilistic reliability assessment and planning approach applied to smart distribution networks, which also involves distributed energy resources such as post-contingency DR for network support.
Large-scale deployment of reliable smart electricity metering networks has been considered as the first step towards a smart, integrated and efficient grid. On the consumer’s side, however, the real impact is still uncertain and limited. This paper evaluates the consumer’s perspective in the city of Västerås, Sweden, where full implementation of smart meters has been reached. New services, such as consumption feedback and the possibility to choose dynamic electricity pricing contracts, have been available from the adoption of this infrastructure. A web-based survey evaluating customers’ perception of these new services was carried out. The survey included consumers’ personal information, preferences about the type of information and the frequency of delivery and the preference for electricity pricing contracts. The results showed that the electricity consumption information offered by distribution system operators (DSOs) today is not detailed enough for customers to react accordingly. Additionally, while variable pricing contracts are becoming more popular, the available pricing schemes do not encourage customers to increase their consumption flexibility. Therefore, more detailed information from the smart meters should be made available, including disaggregated electricity consumption per appliance that would allow consumers to have more control over their energy consumption activities.
This paper discuss the smoke sensor and the relay control in the smart home.STM32 is used as the central part of the whole system and LwIP protocol is also applied to transfer data. The system uses the MQ-2 smoke sensor detect the concentration of combustible gases in air, and uses the SRD-05VDC-SL-C to close and cut off the circuit. The paper also discuss the sensitivity characteristics and the temperature and humidity effect of the smoke sensor. At the end of the paper, it is given the C code in the KEIL MDK environment.
The smart grid is widely considered as an efficient and intelligent power system. With the aid of communication technologies, the smart grid can enhance the efficiency and reliability of the grid system through intelligent energy management. However, with the development of new energy sources, storage and transmission technologies together with the heterogeneous architecture of the grid network, several new features have been incorporated into the smart grid. These features make the energy trading more complex and pose a significant challenge on designing efficient trading schemes. Based on this motivation, in this paper, we present a comprehensive review of several typical economic incentive approaches adopted in the energy-trading control mechanisms. We focus on the technologies that address the challenges specific to the new features of the smart grid. Furthermore, we investigate the energy trading in a new cloud-based vehicle-to-vehicle energy exchange scenario. We propose an optimal contract-based electricity trading scheme, which efficiently increases the generated profit.
There has been a huge amount of coverage in the press about the great potential uses of bitcoin-related technology for financial markets, such as improvements in efficiency. In addition to the supporters of blockchain, many have been critical of its real-life applications within the business world and suggest that what we are witnessing is nothing short of “blockchain hype, ” and that this technology can only be applied to bitcoins. This paper will demonstrate that there are real business cases for improving financial markets based on the lessons learned from cryptocurrencies, but, unlike what the hype-enthusiasts suggest, they are not application of a technology to the existing business models within financial markets. They are reforms of the business model itself. What needs to be exported from the world of cryptocurrencies are aspects of the market organization, inspiration for a different accounting and legal system, and some aspects of the technology. These can result in a huge contribution towards more robust, efficient, and stable markets. However, the process cannot be immediate and effortless, and can only be achieved within a market-wide strategic perspective. In this paper, I develop these concepts initially within a parallel analysis of cryptocurrencies and financial markets. Then, I will focus on a specific business case regarding the collateralization of financial derivatives, which will highlight quantifiable benefits in terms of reducing costs, capital, and risk. It is an example of a situation where the use of cryptocurrency technology is not more important than the business ideas developed in the analysis of cryptocurrencies; yet it was inconceivable prior to the advent of distributed ledgers, smart contracts, and oracles
Christian Thiel, Christopher Brown, Mario Hellenkamp, Marius Spancken
Der Abschlussbericht fasst die Ergebnisse des Forschungs- und Entwicklungsprojektes 2015/2016 im Studiengang Master of Science Wirtschaftsinformatik (FH Münster) zur Themenstellung "Kryptowährungen und Smart Contracts" zusammen. Das Projekt analysierte die Einsatzzwecke, Potenziale und Architekturen von Blockchain-Anwendungen. Des Weiteren wurden verschiedene Fragestellungen zum Nutzen der Blockchain-Technologie in modernen Geschäftsprozessen und zu den technischen Herausforderungen mittels der Entwicklung zweier Prototypen betrachtet. Der erste Prototyp realisiert eine eigene Blockchain, in der verschiedene Angriffsszenarien durchgespielt werden können. Der zweite Prototyp realisiert eine Clearinghouse-Anwendung in Form einer verteilten Smart-Contract-Implementierung (in Ethereum). Der Bericht vermittelt einen Überblick über Ansätze, Strukturen, interne Abläufe und Rahmenbedingungen aktueller Blockchain-Implementierungen. Die erzielten Ergebnisse verdeutlichen neben dem Nutzen auch die Besonderheiten und Einschränkungen der Blockchain-Technologie.
Published as: Shackelford, S., and S. Myers. 2017. “Block-by-Block: Leveraging the Power of Blockchain Technology to Build Trust and Promote Cyber Peace.” Yale Journal of Law & Technology 19:334–388. \n"There has been increasing interest in the transformative power of not only crypto-currencies like Bitcoin, but also the technology underlying them—namely blockchain. To the uninitiated, a blockchain is a sophisticated, distributed online ledger that has the potential, according to Goldman Sachs, to 'change everything.' From making businesses more efficient to recording property deeds to engendering the growth of ‘smart’ contracts, blockchain technology is now being investigated by a huge range of organizations and is attracting billions in venture funding. Even the U.S. Defense Advanced Research Projects Agency (DARPA) is investigating blockchain technology to 'create an unhackable messaging system.' However, the legal literature has largely ignored the rise of blockchain technology outside of its finance, securities, and copyright implications. This Article seeks to address this omission by analyzing the potential impact of blockchain technology on advancing the cybersecurity of firms across an array of sectors and industries with a particular focus on certificate authorities and the critical infrastructure context. Moreover, we examine the rise of blockchains through the lens of the literature on polycentric governance to ascertain what lessons this research holds to build trust in distributed systems and ultimately promote cyber peace."
The past several years have seen the surprising and rapid rise of Bitcoin and other “cryptocurrencies.” These are decentralized peer-to-peer networks that allow users to transmit money, tocompose financial instruments, and to enforce contracts between mutually distrusting peers, andthat show great promise as a foundation for financial infrastructure that is more robust, efficientand equitable than ours today. However, it is difficult to reason about the security of cryptocurrencies. Bitcoin is a complex system, comprising many intricate and subtly-interacting protocol layers. At each layer it features design innovations that (prior to our work) have not undergone any rigorous analysis. Compounding the challenge, Bitcoin is but one of hundreds of competing cryptocurrencies in an ecosystem that is constantly evolving. The goal of this thesis is to formally reason about the security of cryptocurrencies, reining in their complexity, and providing well-defined and justified statements of their guarantees. We provide a formal specification and construction for each layer of an abstract cryptocurrency protocol, and prove that our constructions satisfy their specifications. The contributions of this thesis are centered around two new abstractions: “scratch-off puzzles,” and the “blockchain functionality” model. Scratch-off puzzles are a generalization of the Bitcoin “mining” algorithm, its most iconic and novel design feature. We show how to provide secure upgrades to a cryptocurrency by instantiating the protocol with alternative puzzle schemes. We construct secure puzzles that address important and well-known challenges facing Bitcoin today, including wasted energy and dangerous coalitions. The blockchain functionality is a general-purpose model of a cryptocurrency rooted in the “Universal Composability” cryptography theory. We use this model to express a wide range of applications, including transparent “smart contracts” (like those featured in Bitcoin and Ethereum), and also privacy-preserving applications like sealed-bid auctions. We also construct a new protocol compiler, called Hawk, which translates user-provided specifications into privacy-preserving protocols based on zero-knowledge proofs.
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