Ovaj rad predstavlja ekonomsku analizu kriptovaluta sa slobodnog gledišta. Rad analizira primjenjivost ekonomije na ;kriptovalute; i obratno. Od posebnog interesa je evolucija novca, konkurencija među ;sredstvima razmjene; i koncept novčane ponude. Može se zaključiti da bi u teoriji kriptovalute mogle biti bliže idealu sadašnjeg novca (načina plaćanja) nego bilo koje ostalo sredstvo i ;način plaćanja;, ili čak i zlato, a lako je moguće da će se razviti u tu poziciju. U radu je većinom korišten ;bitcoin; kao nekakav osnovni i općeniti primjer kriptovaluta (uglavnom zato što je prvi oblik kriptovaluta, a i najkorišteniji je oblik kriptovalute). Valjalo bi napomenuti da ;digitalni novac; ne stvaraju ekonomisti nego programeri, što ukazuje na to da su kriptovalute i ostale vrste digitalnog novca drugačije od ostalih sredstava razmjene, a pogotovo po tome što su "digitalne" (nema im fizičkog oblika), te samim time ih ne posjedujemo kao fizički novac, nego kao iznos na računu, koji se može razmjeniti u određeni fizički oblik sredstva razmjene (npr. dolara).
Ismaila Rimi Abubakar, Abubakar U. Benna, Umar G. Benna
The emergence of digital currencies is substantially influencing the growth of global financial markets and cities. Cryptocurrency entrepreneurs (CEs) are reshaping global cities and regions by transforming the way we live, work and interact. This chapter explores how the entrepreneurs use cryptocurrency assets and their underpinning computing technologies to transform the dysfunctional and evolving global cities. The CEs generate funds and create cutting-edge technologies to meet the challenges faced by cities, including unemployment, inadequate and rundown infrastructure and facilities as well as for new development to meet the needs of massive future urbanization. The chapter is organized in five parts. It first introduces the study and presents a background on the concepts of blockchain technologies and cryptocurrency, their emergence and development trend. It then discusses the rise of global cities and how technology impacts them, followed by the potentials and challenges of CEs in transforming global cities and regions. It ends with conclusion and future research directions.
Subscribing to a techno-utopian discourse replacing institutions and experts with “trust in code,” digital alternative currency Bitcoin is pitched as a “math-based money” governed by incorruptible code rather than human regulators. In three cases, which occurred between 2013 and 2015, we examine this system at moments of breakdown. In contrast to the discourse, we find that power is concentrated to critical sites and individuals who manage the system through ad hoc negotiations, and who users must therefore implicitly trust—a contrast we call Bitcoin’s “promissory gap.” But even in the face of such contradictions between premise and reality, the discourse is maintained. We identify four authorizing strategies used in this work: conflating people with devices, assuming actors conform to notions of economic rationality, appealing to technical expertise, and explaining contradictions as temporary bugs. We contend that these strategies are mobilized widely to legitimize a variety of applications of algorithmic regulation and peer production projects.
Guilherme Pinto, João Pedro Dias, Hugo Sereno Ferreira
The Internet of Things is progressively getting broader, evol-ving its scope while creating new markets and adding more to the existing ones. However, both generation and analysis of large amounts of data, which are integral to this concept, may require the proper protection and privacy-awareness of some sensitive information. In order to control the access to this data, allowing devices to verify the reliability of their own interactions with other endpoints of the network is a crucial step to ensure this required safeness. Through the implementation of a blockchain-based Public Key Infrastructure connected to the Keybase platform, it is possible to achieve a simple protocol that binds devices' public keys to their owner accounts, which are respectively supported by identity proofs. The records of this blockchain represent digital signatures performed by this Keybase users on their respective devices' public keys, claiming their ownership. Resorting to this distributed and decentralized PKI, any device is able to autonomously verify the entity in control of a certain node of the network and prevent future interactions with unverified parties.
Blockchain platforms, such as Ethereum, allow a set of actors to maintain a ledger of transactions without relying on a central authority and to deploy scripts, called smart contracts, that are executed whenever certain transactions occur. These features can be used as basic building blocks for executing collaborative business processes between mutually untrusting parties. However, implementing business processes using the low-level primitives provided by blockchain platforms is cumbersome and error-prone. In contrast, established business process management systems, such as those based on the standard Business Process Model and Notation (BPMN), provide convenient abstractions for rapid development of process-oriented applications. This article demonstrates how to combine the advantages of a business process management system with those of a blockchain platform. The article introduces a blockchain-based BPMN execution engine, namely Caterpillar. Like any BPMN execution engine, Caterpillar supports the creation of instances of a process model and allows users to monitor the state of process instances and to execute tasks thereof. The specificity of Caterpillar is that the state of each process instance is maintained on the (Ethereum) blockchain and the workflow routing is performed by smart contracts generated by a BPMN-to-Solidity compiler. The Caterpillar compiler supports a large array of BPMN constructs, including subprocesses, multi-instances activities and event handlers. The paper describes the architecture of Caterpillar, and the interfaces it provides to support the monitoring of process instances, the allocation and execution of work items, and the execution of service tasks.
The research is aimed to determine and analyze: 1) the development of local revenue sources; 2) the capacity of local revenue acceptance; 3) the capacity of local revenue in financing of Palu City; 4) Financial capacity of local Palu government based on regulation of the ministry of Domestic Affairs no. 21, 2007; 5) the leve of fiscal decentralization in financing the expenditure of Palu City; 6) fiscal capacity of Palu government; 7) the capacity of the local revenue to repay local debats. This study is descriptive. Data is collected through interview, literature review, and analysis of Palu government’s financial document. The results show that: 1) the development of local revenue sources indicates that other legitimate of local revenue has the highest growth and contribution of 226.08% and 40.92%; 2) the capacity of local revenue is classified ‘deficient’; 3) the capacity of local revenue is financing expenditure is categorized ‘unable to pay the expenditure’; 4) financial capacity of local Palu government based on the regulation of The Ministry of Domestic Affairs no. 21, 2007 is categorized in ‘low’ and medium’ financial groups; 5) the leve of fiscal decentralization in financing the expenditure of Palu City is still unable to finance the local expenditure; 6) fiscal capacity of Palu government in 2011-2013 budget year in categorized ‘low’ and ‘medium’ in 2014-2015; 7) DSCR ratio shows the capacity of Palu Government to repay local debts.
Matteo Signorini, Matteo Pontecorvi, Waël Kanoun, Roberto Di Pietro
Anomaly detection tools play a role of paramount importance in protecting networks and systems from unforeseen attacks, usually by automatically recognizing and filtering out anomalous activities. Over the years, different approaches have been designed, all focused on lowering the false positive rate. However, no proposal has addressed attacks targeting blockchain-based systems. In this paper we present BAD: the first Blockchain Anomaly Detection solution. BAD leverages blockchain meta-data, named forks, in order to collect potentially malicious activities in the network/system. BAD enjoys the following features: (i) it is distributed (thus avoiding any central point of failure), (ii) it is tamper-proof (making not possible for a malicious software to remove or to alter its own traces), (iii) it is trusted (any behavioral data is collected and verified by the majority of the network) and (iv) it is private (avoiding any third party to collect/analyze/store sensitive information). Our proposal is validated via both experimental results and theoretical complexity analysis, that highlight the quality and viability of our Blockchain Anomaly Detection solution.
Blockchain platforms, such as Ethereum, allow a set of actors to maintain a\nledger of transactions without relying on a central authority and to deploy\nscripts, called smart contracts, that are executed whenever certain\ntransactions occur. These features can be used as basic building blocks for\nexecuting collaborative business processes between mutually untrusting parties.\nHowever, implementing business processes using the low-level primitives\nprovided by blockchain platforms is cumbersome and error-prone. In contrast,\nestablished business process management systems, such as those based on the\nstandard Business Process Model and Notation (BPMN), provide convenient\nabstractions for rapid development of process-oriented applications. This\narticle demonstrates how to combine the advantages of a business process\nmanagement system with those of a blockchain platform. The article introduces a\nblockchain-based BPMN execution engine, namely Caterpillar. Like any BPMN\nexecution engine, Caterpillar supports the creation of instances of a process\nmodel and allows users to monitor the state of process instances and to execute\ntasks thereof. The specificity of Caterpillar is that the state of each process\ninstance is maintained on the (Ethereum) blockchain and the workflow routing is\nperformed by smart contracts generated by a BPMN-to-Solidity compiler. The\nCaterpillar compiler supports a large array of BPMN constructs, including\nsubprocesses, multi-instances activities and event handlers. The paper\ndescribes the architecture of Caterpillar, and the interfaces it provides to\nsupport the monitoring of process instances, the allocation and execution of\nwork items, and the execution of service tasks.\n
Hao Dai, H. P. Young, Thomas J S Durant, Guannan Gong · 8 authors
The governance of data used for biomedical research and clinical trials is an important requirement for generating accurate results. To improve the visibility of data quality and analysis, we developed TrialChain, a blockchain-based platform that can be used to validate data integrity from large, biomedical research studies. We implemented a private blockchain using the MultiChain platform and integrated it with a data science platform deployed within a large research center. An administrative web application was built with Python to manage the platform, which was built with a microservice architecture using Docker. The TrialChain platform was integrated during data acquisition into our existing data science platform. Using NiFi, data were hashed and logged within the local blockchain infrastructure. To provide public validation, the local blockchain state was periodically synchronized to the public Ethereum network. The use of a combined private/public blockchain platform allows for both public validation of results while maintaining additional security and lower cost for blockchain transactions. Original data and modifications due to downstream analysis can be logged within TrialChain and data assets or results can be rapidly validated when needed using API calls to the platform. The TrialChain platform provides a data governance solution to audit the acquisition and analysis of biomedical research data. The platform provides cryptographic assurance of data authenticity and can also be used to document data analysis.
Bitcoin is the first secure decentralized electronic currency system. However, it is known to be inefficient due to its proof-of-work (PoW) consensus algorithm and has the potential hazard of double spending. In this paper, we aim to reduce the probability of double spending by decreasing the probability of consecutive winning. We first formalize a PoW-based decentralized secure network model in order to present a quantitative analysis. Next, to resolve the risk of double spending, we propose the personalized difficulty adjustment (PDA) mechanism which modifies the difficulty of each participant such that those who win more blocks in the past few rounds have a smaller probability to win in the next round. To analyze the performance of the PDA mechanism, we observe that the system can be modeled by a high-order Markov chain. Finally, we show that PDA effectively decreases the probability of consecutive winning and results in a more trustworthy PoW-based system.
This three-paper dissertation studies education systems where decision-making power and funding is shared across different levels of government, their achievement levels and inequality across socieoconomic groups. \nThe first chapter, “Population Density and Educational Inequality: The Role of Public School Choice and Accountability” relates National Assessment of Educational Progress (NAEP) test differences to levels of population agglomeration. Using detailed individual level-data, I establish that being in a denser area is associated with an increase in the socioeconomic gap of about 1 percent for each 10 percent increase in density levels. This is robust to the use of a geographic regression discontinuity design that leverages discontinuities in density across neighboring commuting zones. It is consistent with a theory whereby density leads to greater school socioeconomic segregation. The findings underscore that conventional democratic accountability mechanisms are insufficient to overcome this segregation.\nIn the second chapter, “The Quality and Access Tradeoff in Decentralization Reform: Evidence from Education in the OECD and Spain” (co-authored with Susana Cordeiro Guerra) we study the effect of decentralization reform on education outcomes. While there are theoretical reasons for bringing the locus of decision-making closer to citizens, our knowledge of the effects of decentralization is limited. We first draw on a panel dataset from OECD countries to capture changes on where different decisions are made and their effects on outcomes. Decentralizing has a broadly negative effect on quality indicators but a positive effect on access indicators. We test the argument that upon decentralizing, some regional governments have incentives to assert their legitimacy and pursue highly visible and short-term policies, such as expanding access. Exploiting the exogenous timing of decentralization in Spain (in 1980-2000), we find that variation in the degree of regional assertiveness is related to the magnitude and sign of the effects of decentralization. \nThe third paper, “The Relation between Local Financing and Education Outcomes: Evidence from US School Districts” explores the effects of locally raised revenue. I hypothesize that a higher local revenue share will be related to better school performance, as citizens will be more demanding and in control of the school budget. I look at test scores from the 2007 NAEP, with three empirical approaches. First, I exploit changes in house prices during the 2000 to 2007 boom. Second, I use variation from state fiscal regimes; and third, I leverage covariation within a geographic area. Consistently, local revenue share is associated with about .3-.7% SD higher scores per additional percentage point of local revenue share. It is also associated with greater inequality by socioeconomic status. I find evidence that locally financed districts differ by spending more on teacher salaries and less on administration and that Tiebout competition amplifies the effect of local financing. I find no evidence of a relation between local revenue and citizen participation in education governance. These findings suggest an important behavioral dimension of local financing that would support its continued use.
The term “Bitcoin” conjures up a variety of associations, such as gamers in dark basements, technology enthusiasts in the San Francisco Bay Area, and deceitful, yet highly persuasive “businessmen” involved in Ponzi schemes. Although there is a sense of skepticism surrounding this novel technology, Bitcoin has overcome many negative stereotypes to revolutionize the monetary system. Big names like the New York Stock Exchange and Goldman Sachs have recognized and praised the technology, and an increasing number of businesses like Tesla and Overstock.com are accepting bitcoin. Influential players internationally are endorsing Bitcoin, which validates the notion that Bitcoin—or at least the technology behind it—is not going away any time soon. Unlike the U.S. dollar and most other forms of legal tender, Bitcoin is a decentralized entity that removes the middleman from the equation. Instead of being a part of a system that is often tarnished by greed and human manipulation, Bitcoin is governed by mathematics and encryption processes. Admittedly, there are several issues with Bitcoin, such as its vulnerability to theft and fraud; however, there are many advantages to this currency. A more modern and possibly securer method of payment, Bitcoin is quicker and more economic than the archaic Visa and MasterCard, which were founded in the 1950s and 1960s, respectively, and haven’t been updated since. While Bitcoin will not supplant the U.S. dollar due to an assortment of challenges, Bitcoin holds promise for the future of finance and consumerism. The Bitcoin technology of a block chain has already mobilized many financial institutions to embrace the emerging technology by piloting Bitcoin projects. It is not unrealistic to assume that there is a high potential for a system similar to Bitcoin to replace traditional fiat currency.
Volker Strobel, Eduardo Castelló Ferrer, Marco Dorigo
While swarm robotics systems are often claimed to be highly fault-tolerant, so far research has limited its attention to safe laboratory settings and has virtually ignored security issues in the presence of Byzantine robots---i.e., robots with arbitrarily faulty or malicious behavior. However, in many applications one or more Byzantine robots may suffice to let current swarm coordination mechanisms fail with unpredictable or disastrous outcomes. In this paper, we provide a proof-of-concept for managing security issues in swarm robotics systems via blockchain technology. Our approach uses decentralized programs executed via blockchain technology (blockchain-based smart contracts) to establish secure swarm coordination mechanisms and to identify and exclude Byzantine swarm members. We studied the performance of our blockchain-based approach in a collective decision-making scenario both in the presence and absence of Byzantine robots and compared our results to those obtained with an existing collective decision approach. The results show a clear advantage of the blockchain approach when Byzantine robots are part of the swarm.
Patrick G. Sylim, Fang Liu, Alvin Marcelo, Paul Fontelo
BACKGROUND: Drug counterfeiting is a global problem with significant risks to consumers and the general public. In the Philippines, 30% of inspected drug stores in 2003 were found with substandard/spurious/falsely-labeled/falsified/counterfeit drugs. The economic burden on the population drug expenditures and on governments is high. The Philippine Food and Drug Administration (FDA) encourages the public to check the certificates of product registration and report any instances of counterfeiting. The National Police of Philippines responds to such reports through a special task force. However, no literature on its impact on the distribution of such drugs were found. Blockchain technology is a cryptographic ledger that is allegedly immutable through repeated sequential hashing and fault-tolerant through a consensus algorithm. This project will develop and test a pharmacosurveillance blockchain system that will support information sharing along the official drug distribution network. OBJECTIVE: This study aims to develop a pharmacosurveillance blockchain system and test its functions in a simulated network. METHODS: We are developing a Distributed Application (DApp) that will run on smart contracts, employing Swarm as the Distributed File System (DFS). Two instances will be developed: one for Ethereum and another for Hyperledger Fabric. The proof-of-work (PoW) consensus algorithm of Ethereum will be modified into a delegated proof-of-stake (DPoS) or practical Byzantine fault tolerance (PBFT) consensus algorithm as it is scalable and fits the drug supply chain environment. The system will adopt the GS1 pedigree standard and will satisfy the data points in the data standardization guidelines from the US FDA. Simulations will use the following 5 nodes: for FDA, manufacturer, wholesaler, retailer, and the consumer portal. RESULTS: Development is underway. The design of the system will place FDA in a supervisory data verification role, with each pedigree type-specific data source serving a primary data verification role. The supply chain process will be initiated by the manufacturer, with recursive verification for every transaction. It will allow consumers to scan a code printed on the receipt of their purchases to review the drug distribution history. CONCLUSIONS: Development and testing will be conducted in a simulated network, and thus, results may differ from actual practice. The project being proposed is disruptive; once tested, the team intends to engage the Philippine FDA to discuss implementation plans and formulate policies to facilitate adoption and sustainability. REGISTERED REPORT IDENTIFIER: RR1-10.2196/10163.
This letter questions the true nature (true versus spurious) of the Long Range Dependence (LRD) behavior observed in the returns and volatility series of four Cryptocurrencies (CC). Using a robust approach, this letter shows that the LRD behavior exhibited by the returns and volatility series of Bitcoin, Litecoin, and Ripple is a true behavior, and not a statistical artifact. As for Ethereum, the results show that the true LRD is only supported for the volatility series. Our results confirm the inefficiency of all the considered markets, with the exception of Ethereum.
We study and develop an automated platform for shareholder rights management using Distributed Ledger Technology (DLT), in collaboration with an equity crowdfunding company. DLT has high impact potential for the multi-agent systems domain, as it allows participants to agree on the values of shared variables and keep a history of how the values change over time. DLT also enables participants to know that the shared values are common knowledge. In our application, the shared variables that the agents agree on are the shareholder rights. Knowing that there is common agreement on these rights allows us to develop related applications, such as a shareholder voting system. In this paper, we discuss the shareholder rights management platform and briefly mention a related shareholder voting system, both currently under development.
The problems of formation of revenues of local budgets are investigated in the article. It has been established that significant centralization has affected the reduction of financial independence of local selfgovernment bodies. Changes in the management of local budgets caused by the introduction of a decentralized model encourage local self-government bodies to attract additional financial resources and form a certain economic potential. The feasibility of introducing a public-private partnership through the application ofdifferent methods and tools based on the form of interaction of project participants is substantiated. Suchcooperation requires the organization of complex, mixed private-public structures that can provide largescale infrastructure projects with resources. The advantages of project financing of economic development ofterritories in the framework of public-private partnership (PPP) are revealed.In order to ensure the financial attractiveness of projects implemented on the basis of public privatepartnership and aimed at ensuring the sustainable economic development of regions, it is recommended touse organizational models such as DBFO (Design, Build, Finance, Operate) and DBO (Design, Build, Operate).
A bitcoin node needs to download the full block contents of the entire blockchain, before actually being able to send and receive transactions on bitcoin broadcast network, except simple payment verification clients which require only block headers and bloom filters to sync with others peers available on the network. Transactions/Blocks pass through a complex process at sender and receiver than it apparently looks to be. During transmission transactions/blocks are broken down into smaller chunks of data so that they can be carried on the wire. These chunks are given appropriate headers, encapsulated and then passed through several layers to reach the destination. In this paper we captured Bitcoin packets using Wireshark and deeply investigated and analyzed them. We investigated how bitcoin transaction/block messages work and what values and parameters are considered during this whole process.