Blockchain Papers

Taimur Samad

No abstract is available for this record.

Luisanna Cocco, Giulio Concas, Michele Marchesi

This paper presents an agent-based artificial cryptocurrency market in which heterogeneous agents buy or sell cryptocurrencies, in particular Bitcoins. In this market, there are two typologies of agents, Random Traders and Chartists, which interact with each other by trading Bitcoins. Each agent is initially endowed with a finite amount of crypto and/or fiat cash and issues buy and sell orders, according to her strategy and resources. The number of Bitcoins increases over time with a rate proportional to the real one, even if the mining process is not explicitly modelled. The model proposed is able to reproduce some of the real statistical properties of the price absolute returns observed in the Bitcoin real market. In particular, it is able to reproduce the autocorrelation of the absolute returns, and their cumulative distribution function. The simulator has been implemented using object-oriented technology, and could be considered a valid starting point to study and analyse the cryptocurrency market and its future evolutions.

Linda Marešová

This thesis discusses symmetric random walk, its definition and basic properties. The outset is focused on the probabilistic model and subsequently on basic properties, such as the final position at time n, its mean value and variance. Furthermore, we will see what the scaling must be for the walk to converge to zero, precisely what is the consequence of the strong law of large numbers. In the second chapter we will examine the distribution of the maximum of the symmetric random walk. In chapter 3 we will define stopping time and Markov property of random walks. Then we proof many auxiliary lemmas using basic knowledge of combinatorics. The final part is devoted to the proof of the arcsine distribution, which shows great persistence of the symmetric random walk. Powered by TCPDF (www.tcpdf.org)

Toton Setiawan

Tujuan penelitian untuk mengetahui ada pengaruh pembelajaran ledger-line drills terhadap penguasaan gerak dasar lari sprint. Penelitian ini menggunakan metode kuasi eksperimen dengan desain Pretest-Postest Control Group Design. Adapun populasinya adalah seluruh siswa kelas VII SMP Negeri 1 Cibingbin, sedangkan sampel yang diambil menggunakan teknik purposif sampling diperoleh kelas 7 E dan 7 F, masing-masing sebanyak 23 siswa laki-laki dan perempuan, Instrument penelitian adalah lembar observasi test gerak dasar lari sprint, Hasil penelitian rata-rata pretest kontrol 70,60 kelas eksperimen 71,91. Rata-rata postest kontrol 76,13 dan rata-rata postest eksperimen 80,13 data postes tidak berdistribusi normal, sehingga analisis data menggunakan statistik nonparametrik yaitu dengan menggunakan uji Wilcoxon, diperoleh hasil Jhitung = 126 < Jtabel = 73 sehingga hipotesis diterima. Dapat disimpulkan bahwa ada pengaruh yang signifikan dari penerapan pembelajaran ledger-line drills terhadap penguasaan gerak dasar lari sprint. 
\nABSTRACT
\nThe purpose of the study to know the effect of the ledger-line learning drills on mastering basic motion sprint. This study uses a quasi-experimental pretest-posttest design with control group design. The population is the entire class VII student of SMP Negeri 1 Cibingbin, 
\nwhereas samples taken using purposive sampling technique derived class 7 7 E and F, each as much as 23 boys and girls, is a research instrument observation sheet basic motion sprint test , Results of the study the average pretest control 70.60 71.91 experimental class. Average posttest control mean 76.13 and 80.13 posttest experimental posttest the data are not normally distributed, so the data using nonparametric statistical analysis by using the Wilcoxon test, the results obtained Jhitung = 126 <Jtabel = 73 so that the hypothesis is accepted. 
\nIt can be concluded that there is a significant effect of the application of the ledger-line learning to mastery of basic motion drills sprint.

Jiří Šafka

This paper examines the relationship between virtual currency, the Bitcoin, and the real economy. In the first part the description of the term virtual currency is provided with special focus on Bitcoin. Also the legal and taxation issues are discussed. In the main part the volatility of Bitcoin is inspected using various models from Autoregressive heteroskedasticity models family. We found that the volatility of Bitcoin differs significantly through time and that this relation is captured best by T-GARCH (1,1) model. Finally the relationship between Bitcoin and real economy indicators is observed to be inconsistent and mostly insignificant in time. Thus we conclude that the independency of Bitcoin cannot be rejected. Powered by TCPDF (www.tcpdf.org)

Asri Maharani, Devi Femina, Gindo Tampubolon

In 1991, Indonesia began a process of decentralization in the health sector which had implications for the country's public hospitals. The public hospitals were given greater authority to manage their own personnel, finance and procurement, with which they were allowed to operate commercial sections in addition to offering public services. These public services are subsidized by the government, although patients still pay certain proportion of fees. The main objectives of health sector decentralization are to increase the ability of public hospitals to cover their costs and to reduce government subsidies. This study investigates the consequences of decentralization on cost recovery rate of public hospitals at district level. We examine five service units (inpatient, outpatient, operating room, laboratory and radiology) in three public hospitals. We find that after 20 years of decentralization, district hospitals still depend on government subsidies, demonstrated by the fact that the cost recovery rate of most service units is less than one. The commercial sections fail to play their role as revenue generator as they are still subsidized by the government. We also find that the bulk of costs are made up of staff salaries and incentives in all units except radiology. As this study constitutes exploratory research, further investigation is needed to find out the reasons behind these results.

Sarwar Alam, Humaira Kamal, Alan Wagner

No abstract is available for this record.

Íngrid Vargas, Amparo‐Susana Mogollón‐Pérez, Jean‐Pierre Unger, Maria Rejane Ferreira da-Silva · 6 authors

<strong>Background</strong> Regional-based Integrated Healthcare Networks (IHNs) have been promoted in Brazil to overcome the fragmentation due to the health system decentralization to the municipal level; however, evaluations are scarce. The aim of this article is to analyse the content of IHN policies in force in Brazil, and the factors that influence policy implementation from the policymakers’ perspective. <strong>Methods</strong> A two-fold, exploratory and descriptive qualitative study was carried out based on (1) content analysis of policy documents selected to meet the following criteria: legislative documents dealing with regional-based IHNs; enacted by federal government; and in force, (2) semi-structured individual interviews were conducted to a theoretical sample of policymakers at federal (eight), state (five) and municipal levels (four). Final sample size was reached by saturation of information. An inductive thematic analysis was conducted. <strong>Results</strong> The results show difficulties in the implementation of IHN policies due to weaknesses that arise from the policy design and the performance of the three levels of government. There is a lack of specificity as to the criteria and tools for configuring and financing IHNs that need to be agreed upon between involved governments. For their part, policymakers emphasize the difficulty of establishing agreements in a health system with disincentives for collaboration between municipalities. The allocation of responsibilities that are too complex for the capacity and size of the municipalities, the abandonment of essential functions such as network planning by states and the strategic role by the Ministry, the ‘invasion’ of competences among levels of government and high political turnover are also highlighted. <strong>Conclusions</strong> The implementation of regional-based IHN policy in Brazil is hampered by the decentralized organization of the health system to the municipal level, suggesting the need to centralize certain functions to regional structures or states and to define better the role of the government levels involved.

Isaac Pflaum, Emmeline Hateley

The recent development of virtual currencies, such as Bitcoin, as well as the computer networks that support them, have opened new avenues for the unbanked to reduce transaction costs and gain access to capital without reliance on existing remittance networks or traditional, often foreign, banking institutions that are the primary focus of Basel III. As this Paper will illustrate, however, the use of Bitcoin as a virtual currency is just the beginning of what can become a larger trend towards disintermediation of the delivery of financial services more generally. To realize the full potential of this revolutionary technology, however, it is essential that a coherent regulatory approach be developed that will address abuses of the technology, including fraud, money laundering, and tax evasion, such as what has recently been brought to light in the Silk Road case. In the absence of coordinated international action, a robust extraterritorial application of the U.S. Criminal Code appears to be the most viable option for the United States to shape the development of this technology as a legitimate complement to the international banking system. This Article begins with a discussion of what Bitcoin is, why it is important, and how it has been regulated to date in the United States and elsewhere. This is followed by a discussion, using the Silk Road case as a guide, of how the extraterritorial use of the U.S. Criminal * Isaac Pflaum is a consultant at DisputeSoft, an expert witness firm specializing in liability issues arising in computer software cases. Mr. Pflaum is a licensed attorney and patent agent with extensive experience in IT and development of software for high-performance and parallel computing environments. Before joining DisputeSoft in 2013, he received an LL.M. and J.D. from Georgetown University Law Center. During law school, he interned with the White House Office of Science and Technology Policy, the U.S. Department of Justice, the U.S. International Trade Commission, the Court of Federal Claims and the U.S. Patent and Trademark Office. Prior to attending law school, Isaac received a master’s degree in chemistry for developing massively parallel protein simulation software for the study of HIV and tuberculosis drug targets. Mr. Pflaum was also a guest researcher in the Computational Science Center at Brookhaven National Laboratory. † Emmeline Hateley is a J.D. candidate at Georgetown University Law Center (2015); she received her B.S. in Business Administration (International Business), cum laude, at the University of Southern California. © 2014, Isaac Pflaum and Emmeline Hateley.

Aron Hogden

For over forty years, South Dakota courts have presumed the Fourth Amendment does not require an officer making an arrest for drunk driving to obtain a warrant before requiring a blood Officers, acting on this presumption, have required suspects to submit to blood tests even after the suspect refuses. Recent case law shows this presumption is mistaken. The need for a warrant depends on the totality of the circumstances. The South Dakota judiciary should act to reclaim the weighty role of standing between police officers seeking evidence through a Fourth Amendment search DUI cases and the citizenry they have sworn to protect. To accomplish this, the judiciary should unequivocally articulate circumstances that require a warrant and circumstances where police officers may forego obtaining a warrant. When police officers clearly understand what the courts expect, the officers' job is made easier, the judiciary's warrant approval process becomes more efficient, and the citizens' rights are better protected. I. INTRODUCTION The Fourth Amendment (1) requires police officers obtain a warrant before a person arrested for Driving Under the Influence (DUI) can be required to submit to a blood (2) If, however, the police officer reasonably believes he faces an emergency in which the delay necessary obtaining a warrant ... threaten[s] 'the destruction of evidence,' the officer may forego the warrant requirement. (3) This exception to the general warrant requirement falls within what are known as exigent circumstances. (4) In a DUI case, the most important evidence of the crime obtaining a warrant that are not as prevalent urban jurisdictions. (176) These include: the lack of cell phone coverage to call a magistrate, distance to medical facilities, and the unavailability of a magistrate to make the warrant determination. (177) Each future determination made by South Dakota courts will help inform police officers and prosecutors about how to conform their procedures to Fourth Amendment requirements, however the courts should not wait to spell out general guidelines: too much is at stake. (178) In the meantime, courts should not exclude the BAC evidence where an officer relied on the Supreme Court of South Dakota's past decisions condoning warrantless nonconsensual blood tests DUI cases. (179) After all, the purpose of the exclusion of evidence for Fourth Amendment violations is to deter future conduct, not to penalize reasonable reliance on past judicial precedent. (180) South Dakota courts should, on the other hand, caution officers that creating exigency by artificially delaying a blood draw would be rejected. (181) C. GUIDELINES FOR OFFICERS Unfortunately, based on the most current statement of the law governing DUI blood tests, A police officer ... would have no idea--no idea--what the Fourth Amendment requires of him, once he decides to obtain a blood sample from a drunk driving suspect who has refused a breathalyzer test. (182) This confusion can, and should, be cleared up at the jurisdictional level. (183) As a starting point, police officers should get a warrant whenever possible, not just to meet Fourth Amendment requirements, but also because warrants insulate the blood test from a suppression motion and switch the burden of proof to the defendant claiming the search, i.e., blood test, was unlawful. (184) South Dakota allows telephonic warrants, but they are not streamlined. (185) This type of warrant requires an officer to fill out the warrant application and read it verbatim to the issuing magistrate. (186) Once the magistrate approves the warrant, the requesting officer can sign the magistrate's name. (187) Because the circumstances a DUI case are often routine, prosecutors and court officers should advocate for a more efficient process including creating form warrants that require less time to fill out yet still provide individualized and detailed information to the issuing magistrate. …

Iddo Bentov, Ariel Gabizon, Alex Mizrahi

We study decentralized cryptocurrency protocols in which the participants do not deplete physical scarce resources. Such protocols commonly rely on Proof of Stake, i.e., on mechanisms that extend voting power to the stakeholders of the system. We offer analysis of existing protocols that have a substantial amount of popularity. We then present our novel pure Proof of Stake protocols, and argue that they help in mitigating problems that the existing protocols exhibit.

Barbara Majovská

The purpose of my thesis is to analyse the tools and consequences of the fiscal federalism in Spain. Decentralization process has started along with democratization since passing new Constitution in 1978. It has been mainly reaction to cultural, historical and political reasons of creation of Autonomous Communities. Economic crisis stroke the Spanish economy very strongly and has been a challenge for the whole financing model. Thus, the main aim of my thesis is to deal with the recent development of the financing model. Since Spain is a member of the European Union, I describe also tools of the fiscal federalism put forward by the European Union. Spain is considered to be one of the most decentralized countries in Europe. In my thesis I want to prove that further decentralization has been confirmed by reforms responding to the economic crisis. Then, I want to show that used tools of fiscal federalism are profitable for both state and autonomous communities and positively affect economy of Spain and that they has helped to deal with economic crisis. Finally, I want to show that Spain is getting closer to federal arrangement of government. As has been proved, decentralization is still prevailing tendency in financing model of autonomous communities. But central government has been proposing...

Dinesh, Erlich, Gilfoyle, Jared · 6 authors

On February 2014, $650.000.000 worth of Bitcoins disappeared. Currently it is unclear whether hackers or MtGox, the largest Bitcoin exchange, are to be blamed. In either case, the anonymous and unregulated nature of the Bitcoin system makes it practically impossible for innocent victims to get their money back. We have investigated the technical possibilities, solutions and implications of introducing a regulatory framework based on redlisting Bitcoin accounts. Despite numerous proposals, the Bitcoin community has voiced a strong opinion against any form of regulation. However, most of the discussions were based on speculations rather than facts. We strive to contribute a scientific foundation to these discussions and illuminate the path to crypto-justice.

Ming-Hsiung Hsiao, Liang-Chun Chen

No abstract is available for this record.

Yuesheng Zhu, Limin Ma, Jinjiang Zhang

Abstract As one of the most important trusted third‐party‐based authentication protocols, Kerberos is widely used to provide authentication service in distributed networks. However, it is vulnerable to common brute force password‐guessing attacks because of its password‐based mechanism. Some enhanced Kerberos protocols based on public key cryptography were proposed as solutions, but they require excessive computation and communication resources. In this paper, a new enhanced Kerberos protocol with non‐interactive zero‐knowledge proof is proposed, in which the clients and the authentication server can mutually authenticate each other without revealing any information during the authentication process. Our security analysis and experimental results have shown that the proposed scheme can resist password‐guessing attacks and is more convenient and efficient than previous schemes. Copyright © 2014 John Wiley &amp; Sons, Ltd.

José Antonio Montenegro, Javier López

No abstract is available for this record.

Adrian Blundell‐Wignall

The financial crisis has led to a widespread loss of trust in financial intermediaries of all kinds, perhaps helping to open the way towards the general acceptance of alternative technologies. This paper briefly summarises the crypto-currency phenomenon, separating the ‘currency’ issues from the potential technology benefits. With respect to crypto currencies, the paper argues that these can’t undermine the ability of central banks to conduct monetary policy. They do, however, raise consumer protection and bank secrecy issues. The valuation of Bitcoins and price volatility issues are discussed, as well as electronic theft, contract failures, etc., all of which could result in large losses to users and hence ultimate costs to the taxpayer (e.g. the failure to provide adequate private pensions resulting in increased reliance on public pensions). The anonymity features of the crypto-currencies also facilitate tax evasion and money laundering, both of which are major public policy concerns. The technology associated with crypto-currencies, on the other hand, could ultimately shift the entire basis of trust involved in any financial transaction. It is an innovation that creates the ability to carry out transactions without the need for a trusted third party; i.e. a move towards trust-less transactions. This mechanism could work to eliminate the role of many intermediaries, thereby reducing transactions costs by introducing much needed competition to incumbent firms. The generic issues that policy makers need to examine are summarised.

Jhon Boza, Maria Feijóo

This study addresses the entrepreneurial systems from university campuses, theoretical foundations of business incubators and the analysis of entrepreneurship that contribute to the local development of Quevedo canton, Los Ríos province in Ecuador. There is a higher education institution in Quevedo canton where, in the case of the Técnica Estatal University of Quevedo, productive initiatives are boosted, developing programs with the aim of improving the economic situation of the community. It is important to point out that in the 2008’s Constitution of Ecuador family protection is decisively included, enacting the coordination of actors and resources from the mixed economy regulated by the Good Living (Sumak Kawsay), aiming at developing productive systems at all levels from the precarious economies supported by productive stimulus, as well as from local and provincial decentralized autonomous governments which have to include a percentage for the local productive complex assisted by these institutions in their budget. Higher education institutions should not isolate themselves from this reality and they should participate by becoming the link between the government (represented by local and provincial governments, subsecretaries and ministries) and the community. As a result of the situation educational institutions participate from the academia and production encouragement at all levels, making the most out of the expertise found in educators from different fields. A variety of studies on company systems, regional development and local entrepreneurship show that it has been demonstrated by different international institutions and organizations. The public sector has the capacity to act as a motor oriented to a more productive and sustainable economic model over time. In this research it is demonstrated the need of identifying new local entrepreneurships that foster economic projects that contribute to sustainable local development. By means of this system the Good Living is secured, turning into a necessary tool for development, showing the important role of design, performance and evaluation of the public policies in regional progress.

Aaron Belzer

In equal protection jurisprudence, courts adhere to a three-tiered system of review to determine the constitutionality of laws that rely on classifications of people. Strict scrutiny is the most searching inquiry, followed by intermediate scrutiny, and then rational basis. Rational basis review is the default. The two heightened levels of scrutiny apply to only a handful of already-identified groups. As a general principle, courts are deferential to the other branches of government. However, there is a departure to that principle when it comes to individual rights. That is, rational basis review is exceptionally deferential to the government. When individual rights are at stake, courts typically require the government to prove that its action is constitutional in nature and justified in fact. But under rational basis review, courts require the challenger of a law to disprove every conceivable, possible rationale for a law, regardless of whether it was actually a motivating factor behind the legislation. This standard has been interpreted to mean that even if a judge can imagine any reason why a rationale could — even hypothetically — justify a law, then the law stands as constitutional. Often governments do not even assert a rationale for their actions. Rather challengers must disprove even the wildest, most speculative and hypothetical justifications, which could include those introduced by the judge herself.This Article begins by revealing several of the inherent shortcomings of the current rational basis standard. That standard undermines principles of adversarial adjudication, destabilizes other individual rights doctrines, leaves the rights of certain citizens with virtually no protection, and legitimizes discriminatory animus. In effect, rational basis review preserves a discriminatory status quo, meaning that as society’s values evolve, the Equal Protection Clause becomes less capable of protecting those values. Those troubling consequences need not persist. This Article proposes an alternative and improved in standard of review for the least intrusive level of judicial scrutiny in the tiered equal protection framework. This standard, which I call “rationale review,” shifts the burden of proof onto the government to show a reasonable, fact-based justification for laws that classify people. This standard would only marginally increase the burden on governments defending laws that involve classification of people, but it would require those governments to proffer at least an iota of evidence of a constitutionally permissible justification. Rationale review would not dramatically alter the current tiered equal protection framework. Those groups currently afforded heightened scrutiny would continue to receive such a standard of review. And laws concerning all other groups would continue to receive the least intrusive judicial inquiry under the tiered framework. Under rationale review, however, the government would bear the burden of proof in justifying as constitutional — with facts — those laws that make classifications of people.

Isidro Pastor Jordà

No abstract is available for this record.

Fucai Zhou, Yuxi Li, Qingshi Zhou, Jingwei Miao · 5 authors

Electronic cash is an electronic form of currency, which allows the cash transactions over communication networks under privacy protections. However, it still has some aspects that have not been well studied. Known constructions suffer from at least one of the following limitations: (1) relying on a random oracle, (2) not supporting multiple bank setting and users dynamically joining or (3) prohibitively expensive. In this paper, we propose a new electronic cash system that avoids all these limitations. In other words, our system is anonymous against chosen-ciphertext attack (CCA) in the standard model, and supports multiple banks enrolling and users dynamically joining, which is achieved by the utilization of non-interactive zero-knowledge proof and dynamic group signature. Finally, in the standard model, a formal security proof is given to claim that our system has CCA anonymity, unforgeability, traceability and no double-spending. Compared with the existing systems, ours has advantages of both the efficiency and security.

Ruthmae Sears, Óscar Chávez

No abstract is available for this record.

Fábio Machado de Oliveira, Maria Totti, Vanuza de Silva Pereira Ney

Esse trabalho apresenta uma tecnologia de rede ponto-a-ponto que esta em crescente consolidacao, um sistema eletronico de pagamento que usa um protocolo de criptografia aberto para validar suas transacoes, denominado Bitcoin, tendo este uma proposta de virtualizacao completa da moeda excluindo a participacao de instituicoes certificadoras como governos e orgaos financeiros nas garantias de operacoes virtuais com dinheiro real. Em seguida sao apresentados os artefatos tecnologicos que sustentam a eliminacao do intermediario confiavel e suas taxas de cobranca na mediacao de pagamentos online. Apoiado em teoricos como: Satoshi Nakamoto, Jack Weatherford e outros, iremos abordar questionamentos a respeito da aceitacao e adesao ao Bitcoin nas diversas perspectivas impactadas com essa nova tecnologia, principalmente em paises que enfrentam inflacao e crises financeiras. Observar o fenomeno de flutuacao sempre crescente da cotacao do Bitcoin, bem como, os agentes externos que influenciam nessas oscilacoes. Contribuir para a formacao de uma consciencia holistica dessa nova tecnologia, que encontra fomento na sociedade em rede e que a cada dia esta mais conectada foi o principal sentido desse trabalho, contribuindo para o avanco da fronteira do conhecimento no ciberespaco e a constante conquista de consciencia e cidadania na internet.

Gian Paolo Lazzer, Valentina Moiso

The bitcoin is being proposed as a useful case study to problematize the issue of designing new forms of money given its apparent uniqueness from the historical point of view . There are two arguments to support this view . The two assumptions in the light of a broader and more detailed analysis reveal that they are unfounded . The proposal advanced here is to consider the novelty of bitcoin brought about another issue and to discuss the broader social implications as well .