El Bitcoin (BTC) va apareciendo regularmente en los medios de comunicacion por diversos motivos. Desde la quiebra de una conocida casa de cambios en Estados Unidos (Mt. Gox) hasta la constitucion de una sociedad cuyo capital social esta denominado exclusivamente en esta criptomoneda pasando por el anuncio de que algunas tiendas de la Milla de oro de Madrid acepten como medio de pago la moneda virtual no regulado de la que trata este trabajo. Nosotros nos proponemos estudiar, desde el Derecho privado, la configuracion juridica del BTC planteando cuestiones e intentando resolverlas. La conclusion a la que llegamos es que es una moneda virtual que funciona, hoy por hoy, de forma similar a una divisa y que el legislador deberia limitar su intervencion, el dia en que asi lo decida, a permitir su conversion a la moneda fiduciaria de uso legal.
It is well known that the novel The History of the Siege of Lisbon undertakes a revision of the origin of Portuguese identity by revealing the fragile historical fundament in the sense of a culture’s hybridity. This study argues that in this story the problematic search for ‘pure’ historical origin is intertwined with the search for ‘pure’ text. By analyzing the dense intertextual net of Raimundo Silva’s doubtful and creative proof-reading it becomes evident that it is less a question of proof-reading than of translating that is at stake in this historiographic metafiction. From this perspective the adventure of reading/writing turns out to be a question of criss-crossed identity that is extended to the novel’s reader: in the case of its translation into German, the new text has to tackle with the reader’s cultural affinity with the Crusaders.
We deal with the general problem of scattering by open arcs in two-dimensional space. We show that this problem can be solved by means of certain second-kind integral equations of the form , where and are first-kind integral operators whose composition gives rise to a generalized Calderón formula of the form in a weighted, periodized Sobolev space. (Here is a continuous and continuously invertible operator and is a compact operator.) The formulation provides, for the first time, a second-kind integral equation for the open-arc scattering problem with Neumann boundary conditions. Numerical experiments show that, for both the Dirichlet and Neumann boundary conditions, our second-kind integral equations have spectra that are bounded away from zero and infinity as k → ∞; to the authors’ knowledge these are the first integral equations for these problems that possess this desirable property. This situation is in stark contrast with that arising from the related classical open-surface hypersingular and single-layer operators N and S , whose composition NS maps, for example, the function ϕ = 1 into a function that is not even square integrable. Our proofs rely on three main elements: algebraic manipulations enabled by the presence of integral weights; use of the classical result of continuity of the Cesàro operator; and explicit characterization of the point spectrum of , which, interestingly, can be decomposed into the union of a countable set and an open set, both of which are tightly clustered around . As shown in a separate contribution, the new approach can be used to construct simple, spectrally accurate numerical solvers and, when used in conjunction with Krylov-subspace iterative solvers such as the generalized minimal residual method, it gives rise to a dramatic reduction in the number of iterations compared with those required by other approaches.
Les cryptomonnaies sont des monnaies numériques, qui se sont développées hors de tout contrôle étatique et qui fonctionnent de manière décentralisée. Bien qu’étant encore à leurs balbutiements, ces cryptomonnaies, à l’instar du Bitcoin, soulèvent de nombreuses questions juridiques. Dans ce mémoire, seront analysées les différentes définitions qui pourraient inclure la cryptomonnaie, avant de nous concentrer sur la définition de la monnaie numérique. Ensuite, seront étudiés, les aspects criminogènes des cryptomonnaies et la volonté des États d’avoir un certain contrôle sur celles-ci. Puis après nous être concentré sur la fiscalité applicable aux monnaies numériques, il sera nécessaire d’examiner l’étendue de la protection des consommateurs, dans leurs rapports aux cryptomonnaies. Pour ce faire nous nous appuierons, entre autre, sur les lois canadiennes, françaises et américaines. Toutefois vous vous en rendrez-compte, les cryptomonnaies n’ont pas encore été totalement englobés dans les systèmes juridiques des trois pays étudiés, et les tribunaux n’ont été saisis que dans très peu d’affaires relatives aux monnaies numériques, ce qui implique que de nombreuses incertitudes juridiques persistent à l’heure actuelle.
The use of security certificates under the Cloud environment is the foundation to establish mutual trust between the Cloud and the user. In this paper, we propose an authentication method based on zero-knowledge proof and the mind of key escrow. With the method, authentication will not only satisfy the requirement anonymity and security but also can recover the real identity information in special circumstances with the cooperation of multiple parties. We will show that this proposed method is more suitable for promotion through analysis and comparison with an existing scheme.
Zero-knowledge proof protocol is a basic cryptographic technique. And zero-knowledge proof of double discrete logarithm has some particular properties, so it has been widely applied in many security systems. But the efficient problem of zero-knowledge proof of double discrete logarithm has not been solved to this day, since there are some special difficulties in computing this kind of knowledge proof. Hence, the time complexity and the space complexity of existing schemes are all O(k), where k is a security parameter. After redesigning the basic construction of knowledge proof, we provide a new zero-knowledge proof of double discrete logarithm, which is the first scheme with O(1) time complexity and O(1) space complexity. If introducing an off-line TTP (trusted third party), we can provide two additional zeroknowledge proof schemes of double discrete logarithm, one is even more efficient than the first one, the other one solves another open problem, which is how to efficiently prove the equality of double discrete logarithms in zero-knowledge way, and the existing techniques cannot solve this problem. We also provide the detailed security proofs of our designs and efficiency analysis, comparing with the existing schemes. The significant improvement in efficiency of this basic cryptographic technique is also helpful for many security systems.
In dieser Thesis wird ein Marktindex konstruiert, wobei neu entwickelte Methoden für solch eine Aufgabe verwendet werden. Die Entscheidung über die Anzahl der Indexteilnehmer wird mithilfe des AIC und BIC Kriteriums getroffen und die Liquiditätsregel wird auf Grundlage der BIS Umfrage ermittelt. Dieser neu entwickelte Index, CRIX, wird dann benutzt, um den Kryptowährungsmarkt gegen Bitcoins und andere Märkte zu vergleichen. Es wurde herausgefunden, dass dieser Markt wesentlich risikoreicher ist als andere Märkte. Es wird außerdem ein Minimum Varianz CRIX und ein optimales Vorhersagemodel für den Index entwickelt, wobei Daten aus sozialen Netzwerken verwendet werden.
Sabina Nuti, Federico Vola, Anna Bonini, Milena Vainieri
The Italian Health care System provides universal coverage for comprehensive health services and is mainly financed through general taxation. Since the early 1990s, a strong decentralization policy has been adopted in Italy and the state has gradually ceded its jurisdiction to regional governments, of which there are twenty. These regions now have political, administrative, fiscal and organizational responsibility for the provision of health care. This paper examines the different governance models that the regions have adopted and investigates the performance evaluation systems (PESs) associated with them, focusing on the experience of a network of ten regional governments that share the same PES. The article draws on the wide range of governance models and PESs in order to design a natural experiment. Through an analysis of 14 indicators measured in 2007 and in 2012 for all the regions, the study examines how different performance evaluation models are associated with different health care performances and whether the network-shared PES has made any difference to the results achieved by the regions involved. The initial results support the idea that systematic benchmarking and public disclosure of data are powerful tools to guarantee the balanced and sustained improvement of the health care systems, but only if they are integrated with the regional governance mechanisms.
Open access
Healthcare Quality and Management
Patient Satisfaction in Healthcare
Health Systems, Economic Evaluations, Quality of Life
Renate Hartwig, Robert Sparrow, Sri Budiyati, Athia Yumna · 7 authors
We exploit variation in the design of subnational health-care financing initiatives in Indonesian districts to assess the effects of these local schemes on maternal care from 2004 to 2010. The analysis is based on a district pseudopanel, combining data from a unique survey among District Health Offices with the Indonesian Demographic and Health Surveys, the national socioeconomic household surveys, and the village census. Our results show that these district schemes contribute to an increase in antenatal care visits and the probability of receiving basic recommended antenatal care services for households that are not targeted by the national health insurance programs. We observe a decrease in home births. However, there is no effect on professional assistance at birth. We also observe variation in scheme design across districts as well as constraints to the effectiveness of local schemes. Including antenatal and delivery services explicitly in benefits packages and contracting local rather than national health-care providers increases the effects on maternal care. Increasing population coverage reduces effectiveness, delineating limitations to local funding and risk pooling. Furthermore, we do not find any effects for districts outside Java and Bali, where access to basic health care remains a key policy concern.
Self-organization provides a suitable model for developing self-managed complex distributed systems, such as grid computing and sensor networks. Unlike current related studies, which propose only a single principle of self-organization, this mechanism synthesizes the three principles of self-organization: cloning/ spawning, resource exchange and relation adaptation. Based on this mechanism, an agent can autonomously generate new agents when it is overloaded, exchange resources with other agents if necessary, and modify relations with other agents to achieve a better agent network structure. In this way, agents can adapt to dynamic environments. The proposed mechanism is evaluated through a comparison with three other approaches, each of which represents state-of-the-art research in each of the three self-organization principles. Experimental results demonstrate that the proposed mechanism outperforms the three approaches in terms of the profit of individual agents and the entire agent network, the load-balancing among agents, and the time consumption to finish a simulation run. In addition, in a dynamic environment, it is nearly impossible to use a static, design time generated system structure for efficient problem solving. Instead, the system needs to be able to self-organize at runtime, which means that the components of the system are responsible for adapting themselves to suit the dynamic environment. Self-organization is usually defined as "the mechanism or the process enabling the system to change its organization without explicit external command during its execution time.
The transnational nature of many environmental problems may demand international collaboration, but whether environmentalists supply such cooperation depends on political factors. Doherty and Doyle examine such processes at one of the world’s leading environmental non-governmental organizations (NGOs). In Environmentalism, Resistance, and Solidarity, they use the case of Friends of the Earth International (FoEI) to explore whether and how activists from North and South can develop “common responses” to global problems (p. 25).The book’s major contribution is its detailed look inside this major NGO. Doherty and Doyle were granted access by senior leadership, allowing them to amass a wide array of resources. They designed a survey of the NGO’s national chapters that allowed them to trace the flow of resources and information. Using site visits, observations of international meetings, and archival material, Doherty and Doyle offer a rich understanding of what it means to “think globally, act locally.”This close perspective allows them to explore how Northern and Southern chapters have shaped FoEI over time. David Brower founded the organization in the United States in 1969, but its center of gravity quickly moved to Western Europe, where national chapters employed a mix of tactics, including public demonstrations, expert research, and traditional lobbying. In the 1980s, the focus moved from mostly local environmental concerns to a more international perspective. The authors identify the jointly conducted rainforest campaign (orchestrated by the English and Malaysian chapters) as an important milestone in the NGO’s transnational campaigning.Doherty and Doyle explain how resistance from Southern chapters has pushed FoEI to embrace a more radical and less strictly environmental sensibility. In 2002, Equador’s national chapter resigned from FoEI, decrying the domination of Northern groups. This “bombshell” (p. 49) rocked the weak federation and led to a reexamination of its structure and mission.Three elements of the federation’s new mission are noteworthy. First, people and nature now receive equal treatment. Many Southern chapters work closely with indigenous communities on land rights and pollution, and FoEI has strategic alliances with La Via Campesina (a small farmers movement) and the World March of Women. Second, national chapters of FoEI do not agree on whether capitalism is sustainable. Latin American chapters adopt explicit critiques of neoliberalism, while European chapters prefer the more moderate language of economic justice; FoEI provided a forum for debate on these matters but found no resolution. Finally, FoEI is fairly united in resistance to corporate power. The different national chapters have abandoned the reformist agenda of corporate social responsibility and targeted specific corporate practices. In sum, of the many possible frames within the environmental movement, FoEI comes together around the frame of environmental justice.Doherty and Doyle argue that, compared to other major environmental NGOs like Greenpeace and WWF, Friends of the Earth is engaging in a more “emancipatory environmental politics” (p. 212) by providing an international forum at which North and South can meet. They argue that the weakness of the Friends of the Earth brand (most national chapters do not use that name) is actually a strength, allowing FoEI to build effective networks and set aside potentially distorting concerns over securing donors. Against these optimistic assessments, however, the authors hint at important questions about the efficacy of the group’s international structure. The forum model reveals conflicts but does not resolve them. The ties among national chapters are weak, so that no one chapter is challenged to alter its practices or redistribute its resources. Resources are still concentrated in Europe, which also has its own strong regional-level organization (FoE Europe). The capacity of the international secretariat is limited, and relatively few staff in the global federation work on international issues. In short, FoEI’s egalitarian and decentralized structure has created space for Southern voices but failed to challenge underlying inequalities.A more extensive assessment of FoEI’s political impact could have complemented the book’s insights into the group’s organizational structure. Doherty and Doyle explore two campaigns that are widely pursued across the FoEI federation, but the cases of food security and climate change reveal a diversity of strategies with mixed results. In food security, for example, the call for “redressing fundamental imbalances” (p. 159) is most needed but least apparent in the North, as Northern chapters largely neglect the question of rebuilding global structures of food production. Doherty and Doyle focus their attention inside the organization, but a full assessment of organization’s political achievements likely requires interviews and data gathered from the external targets and partners of FoEI.Those interested in international NGOs, Southern environmentalism, and organizational structure will all find valuable insights in this book. Problematically, a book that seeks to inform actual practice is being sold at a price point (more than US$95) that is inaccessible for most practitioners and individual scholars. A paperback release would increase its accessibility and readership.For Doherty and Doyle, Friends of the Earth today “remains a coalition of largely autonomous national organizations rather than a single global NGO, and the price it pays for this is possibly that its impact on international politics is therefore weaker than that of other more centralized NGOs” (p. 211). The key question is whether a structure that favors long-term engagement of Northern and Southern voices is a path towards the resistance politics that NGOs are often thought to embody.
Trusted timestamping is a process for proving that certain information existed at a given point in time. This paper presents a trusted timestamping concept and its implementation in form of a web-based service that uses the decentralized Bitcoin block chain to store anonymous, tamper-proof timestamps for digital content. The service allows users to hash files, such as text, photos or videos, and store the created hashes in the Bitcoin block chain. Users can then retrieve and verify the timestamps that have been committed to the block chain. The non-commercial service enables anyone, e.g., researchers, authors, journalists, students, or artists, to prove that they were in possession of certain information at a given point in time. Common use cases include proving that a contract has been signed, a photo taken, a video recorded, or a task completed prior to a certain date. All procedures maintain complete privacy of the user's data.
Bitcoin extreme deflationary price instability has hampered its usability, making it impractical for spot transactions and unserviceable for deferred payments. Ametrano (2014) has proposed as Hayek Money a cryptocurrency price stability paradigm of elastic non-discretionary monetary policy. An implementation using a dual asset ledger for stable coins and seigniorage shares is presented here. A DeCentralized Reserve Bank (as Decentralized Autonomous Organization) is introduced as active market agent using bitcoin as reserve asset to preserve price parity. The socially inefficient over-investment of seigniorage revenues in transaction verification can be avoided using proof-of-payment.This schema frees coins from any speculative value, thus favoring money velocity and increasing the number of transactions. Seigniorage shares are effectively to be considered as a participation in a distributed central bank: as such the owners are entitled to seigniorage revenues in exchange for being subjected to the losses associated to coin price stability defense, obliged to validation task duties, and in charge of price index observation.
For any pair $(X,Z)$ of correlated random variables we can think of $Z$ as a randomized function of $X$. Provided that $Z$ is short, one can make this function computationally efficient by allowing it to be only approximately correct. In folklore this problem is known as \emph{simulating auxiliary inputs}. This idea of simulating auxiliary information turns out to be a powerful tool in computer science, finding applications in complexity theory, cryptography, pseudorandomness and zero-knowledge. In this paper we revisit this problem, achieving the following results: \begin{enumerate}[(a)] We discuss and compare efficiency of known results, finding the flaw in the best known bound claimed in the TCC'14 paper "How to Fake Auxiliary Inputs". We present a novel boosting algorithm for constructing the simulator. Our technique essentially fixes the flaw. This boosting proof is of independent interest, as it shows how to handle "negative mass" issues when constructing probability measures in descent algorithms. Our bounds are much better than bounds known so far. To make the simulator $(s,ε)$-indistinguishable we need the complexity $O\left(s\cdot 2^{5\ell}ε^{-2}\right)$ in time/circuit size, which is better by a factor $ε^{-2}$ compared to previous bounds. In particular, with our technique we (finally) get meaningful provable security for the EUROCRYPT'09 leakage-resilient stream cipher instantiated with a standard 256-bit block cipher, like $\mathsf{AES256}$.
The purpose of this study is to analyze performance and constraint factors of local decentralization from the Kim Dae Joong Administration to the Lee Myung Bak Administration in three different parts: administrative affairs, personnel affairs, and finance, and to find out the changes of Central-Local Intergovernmental Relation by Administration. First of all, the administrative affairs decentralization has improved by the increase of autonomous affairs and distribution of affairs, even though autonomous administrative power have maintained. The personnel affairs decentralization has reinforced in autonomy personnel affairs power and personnel distribution. The finance decentralization has maintained or weakened by decrease in autonomy financial power and both revenue & expenditure of tax. The constraint factors of local decentralization were legal & institutional restrictions such as range of affairs, fixed base & rate of tax and local tax structure focused on property taxation, and fiscal neutralism of Ministry of Strategy and Finance. In conclusion, the local decentralization of Korean Government has been improved disproportionately in the aspects of administrative affairs, human resources affairs, and finance. The Kim Dae Joong Administration was inclusive authority model, and the Nho Moo Hyun Administration and the Lee Myung Bak Administration was in the middle between inclusive authority model and overlapping-authority model, so after revival of the local self-governing system, relations between central and local government has been developed.
Ashley S. Harrison, M. Scott Niederjohn, J. R. Clark
Economists define money as anything that is generally accepted in payment for goods and services or in the repayment of debts.1 Paper money and coins clearly fit this definition, but deposits in checking accounts are so widely accepted that they are also considered in the narrowest definition of money used by the Federal Reserve, called “M1.” M1 is the sum of all currency, checkable deposits, and travelers checks. How about savings accounts? These amounts are so quickly convertible into M1 that many economists consider them money too, part of a larger total called M2 that includes all of M1 plus all small denomination time deposits (bank CDs), savings accounts, and money market account balances. M2 then represents a form of money that is less “liquid” (less easily converted and spent) than M1. In addition to this definition, money is expected to satisfy three functions: serve as a medium of exchange, a store of value, and a unit of account. In this article, we will explore what Bitcoin is and why it has been so prevalent in the news of late. Further, we will apply the three functions of money to Bitcoin and discuss whether it should be considered a form of money. Some of the benefits and problems associated with Bitcoin will be discussed along with its future potential.
This article addresses the market for employment services. It adopts a dynamic perspective on welfare markets and demonstrates how the institutional design of quasi‐markets in the Danish Public Employment service has been promoted, altered, and re‐regulated over a period of 10 years. It was in 2002 when quasi‐markets have been created by using the instrument of contracting‐out employment services to private providers. Seen from the perspective of policymakers at the national level, contracting‐out is attractive as it has a buffering function and allows adapting the amount of the public financed employment services comparatively easy to changing needs resulting from changing labor market conditions. However, contracting‐out makes accountability to public goods more difficult as the chain of accountability is stretched or may even be broken. Against the background of accountability scandals, which have revealed the poor quality of privately provided services, the market design was re‐modeled again by replacing standardized national tendering with a decentralized, partnership‐based and dialogue‐oriented approach, where services are developed in joint efforts between purchaser and provider. All in all, the development of quasi‐markets in the Danish Public Employment system can be described as a partial reversal from marketization. Paradoxically, elements of network governance, which were abolished initially, have been introduced again.
Bitcoin is most radical innovation in monetary space for a very long time. It is an entirely private monetary system that runs itself and does not depend on trust in any central authority to honor its promises. Instead, it relies on trust in Bitcoin community or network that verifies transactions and maintains integrity of system. This system of distributed trust creates bitcoins and produces an automatic, tamper-proof bitcoin money supply process. (1) As such, it avoids dangers of discretionary monetary policy--namely, quantitative easing, manipulated interest rates, and need to rely on wise men or women to withstand political pressure or successfully forecast future. Indeed, under Bitcoin there is no monetary policy at all. There is just an automatic monetary rule dictated by Bitcoin protocol designed in 2009 by an anonymous programmer using alias Satoshi Nakamoto. Bitcoin has been widely hailed as a success and has won a substantial following. Unfortunately, underlying economics of Bitcoin mean that it is unsustainable and in all likelihood will be remembered as a failed experiment--at best a pointer to some superior successor. A first-pass intuition into Bitcoin can be obtained from a comparison with stone money in Milton Friedman's (1992) case study, Island of Stone Money. In this story, people of island of Yap in Micronesia used as money large round limestone disks transported from nearby island of Palau. These were too heavy to conveniently move around, so they were placed in prominent places. When ownership was to be transferred (e.g., as part of a dowry, inheritance, or ransom payment), current owner would publicly announce change in ownership but stone would typically remain where it was and islanders would maintain a collective memory of ownership history of stones. This collective memory ensured that there was no dispute over who owned which stones. Similarly, in Bitcoin, record of all transactions, blockchain, is also public knowledge and is regarded as die definitive record of who owns which bitcoins. Both stone money and Bitcoin share a critical feature that is highly unusual for a monetary system: both systems operate via a decentralized collective memory. On February 11, 2009, Nakamoto gave an explanation of thinking behind Bitcoin in an e-mail announcing its launch: root problem with conventional currency is all trust that is required to make it work. The central bank must be trusted not to debase currency, but history of fiat currencies is full of breaches of that trust.... With e-currency based on cryptographic proof, without die need to trust a third-party middleman, money can be secure and transactions complete. Cryptocurrencies, however, face problem of As Nakamoto notes, owner could try to re-spend an already spent coin by [digitally] signing it again to another owner. The usual solution is for a trusted company with a central database to check for double-spending, but that just gets back to trust model.... Bitcoin's solution is to use a peer-to-peer network to check for double-spending. Consequently, the result is a distributed system with no single point of failure. (2) Kevin Dowd is Professor of Finance and Economics at Durham University in United Kingdom and a partner at Cobden Partners. Martin Hutchinson is a journalist and author of Bear's Lair column (www.tbwns.com/category/the-bears-lair). The authors thank Ferdinando Ametrano, Gavin Andresen, Raadhiyah Anees, Steve Baker MP, Roger Brown, Dave Campbell, Akin Fernandez, Dominic Frisby, Jim Harper, Doug Jackson, Gordon Kerr, Jim Rapp, Eric Samieski, Lawrence H. White and Basil Zafiriou for much helpful feedback. We note that several of our readers have expressed serious reservations about our analysis and conclusions. Any remaining mistakes are authors' own. …
Zoran Čekerevac, Zdeněk Dvořák, Ludmila Prigoda, Petar Čekerevac
Bitcoin, digital money got into focus after the Mt Gox crash. It uses P2P interaction where an owner transfers the electronic coin to the next owner signing and adding a hash of the previous transaction and the public key of the next owner. Payment verification is accomplished by notifying the entire network about the transaction. This prevents double-spending and generation of non-existent money. Among the users, there is uncertainty about the safety on the theft and fraud. Among the authorities, there are dilemmas about present and future risks related to the Bitcoin implementation. The article deals with the benefits and risks of Bitcoin use.