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93,175 results · page 3643 of 3,883
Harald Gjermundrød, Ioanna Dionysiou
No abstract is available for this record.
Abdur Chowdhury
The Bitcoin phenomenon—and the technological innovation that made it possible—is interesting, but for investors large and small, the more pertinent question is whether they should buy the digital currency or avoid it. Using both in-sample and out-of-sample settings, we analyze a Bitcoin investment from the standpoint of an investor with a diversified portfolio. Within the in-sample setting, Bitcoin does not yield added value to investors, with a utility function consistent with the mean-variance setting. On the other hand, Bitcoin does offer diversification benefits to investors with negative exponential and power utility functions. However, these benefits are not preserved in the out-of-sample framework. In most cases, the optimal portfolios that include only the traditional asset classes appear to have superior performance. <b>TOPICS:</b>Currency, portfolio construction, performance measurement
Noel Yahanpath, Zeb Wilton
A short time ago, the idea of a decentralised virtual currency based on cryptography technology and operating over a worldwide peer-to-peer network would have been considered science fiction. However, it is now a daily reality for users of bitcoin and other virtual currencies.
Oscar Darmawan
No abstract is available for this record.
Jamal Bouoiyour, Refk Selmi
The present paper seeks to effectively address the following question: What Bitcoin looks like? To do so, we regress Bitcoin price on different variables (potential Bitcoin fundamentals recorded in the literature) by applying an ARDL Bounds Testing approach for daily data covering the period from December 2010 to June 2014. Our findings highlight the speculative behavior of Bitcoin. This virtual currency may be also used for economic reasons. However, there is any sign of being a safe haven. By considering the Chinese trading bankruptcy, the contribution of speculation (proxied by investors’ attractiveness to Bitcoin) remains dominant, indicating the robustness of our results.
Florian Glaser, Martin Haferkorn, Moritz Weber, Kai Zimmermann
Digital currencies are gaining more and more attention against the backdrop of recent events triggered by the ongoing economic crisis. While digital currencies face increasing popularity, the currencies' prices are free floating and subject to high volatility as a result of lacking fundamental valuation methods. On the basis of an overview over the most prominent currency -- Bitcoin -- and an economic literature review we propose an econometric model that incorporates the basic components of the current price discovery process of a digital currency's exchange rate. On the basis of our empirical validation we further show that, in the case of Bitcoin, price volatility is significantly influenced by the media coverage and positive sentiment.
Darlington, Kiarie James
No abstract is available for this record.
Timo-Pekka Huhtinen
OBJECTIVES OF THE STUDY:\n\nThis thesis has three objectives. First, the past development of monetary systems is studied to see how Bitcoin is positioned as the forerunner of a new category. Second, the attitudes and expecta-tions of Finnish stakeholders are studied to recognize the general perception and future outlook for Bitcoin. Third, bitcoins are examined as an investment instrument by studying price drivers and the degree of predictability of future returns.\n\nDATA AND METHODOLOGY:\n\nThe qualitative methods are based on a literature review and an interview study conducted with Finnish stakeholders from different financial institutions and Bitcoin start-ups. The quantitative methods consist of market sizing calculations, a regression analysis, and Granger tests. The regres-sions utilize novel variables network hashrate, network transactions, and bitcoin supply as explan-atory variables for bitcoin price. Also bitcoin price and Google Trends SVI are used as explanatory variables. The market sizing calculations are based on M2 monetary aggregates for USD, EUR, and JPY.\n\nFINDINGS OF THE STUDY:\n\nThe thesis develops a categorization for decentralized cpytocurrencies that takes into account the main developments of the past monetary systems. The interview study reveals optimism for the technology behind Bitcoin and other decentralized systems, while all interviewees accept the un-certainty of Bitcoin survival. The stakeholders perceive the main challenges of Bitcoin to be tech-nological weaknesses, trust, and reputational issues. In terms of market sizing, it is clear that Bitcoin is not currently a serious threat to fiat currencies. Price driver analysis revealed a momen-tum effect in price returns, as well as an inflationary effect caused by the increasing supply. Also the network hashrate was found to forecast future bitcoin returns. The results from the Granger tests challenge the causality assumed in the regressions.
Shawn Bayern
Most legal analysis of Bitcoin has addressed public-law and regulatory matters, such as taxation, securities regulation, and money laundering. This essay considers some questions that Bitcoin raises from a private-law perspective, and it aims to show that technological innovation may highlight problems with conceptualistic, classical rules of private law.
Sébastien Canard, Iwen Coisel, Amandine Jambert, Jacques Traoré
No abstract is available for this record.
Claudio Orlandi, Rafail Ostrovsky, Vanishree Rao, Amit Sahai · 5 authors
The notion of Zero Knowledge introduced by Goldwasser, Micali and Rackoff in STOC 1985 is fundamental in Cryptography. Motivated by conceptual and practical reasons, this notion has been explored under stronger definitions. We will consider the following two main strengthened notions. Statistical Zero Knowledge: here the zero-knowledge property will last forever, even in case in future the adversary will have unlimited power. Concurrent Non-Malleable Zero Knowledge: here the zero-knowledge property is combined with non-transferability and the adversary fails in mounting a concurrent man-inthe-middle attack aiming at transferring zero-knowledge proofs/arguments. Besides the well-known importance of both notions, it is still unknown whether one can design a zero-knowledge protocol that satisfies both notions simultaneously. In this work we shed light on this question in a very strong sense. We show a statistical concurrent non-malleable zero-knowledge argument system for N P with a black-box simulatorextractor. 1
Michel Abdalla⋆, Fabrice Benhamouda, David Pointcheval
Abstract. Smooth Projective Hash Functions (SPHFs), also known as Hash Proof Systems, were first introduced by Cramer and Shoup (Eurocrypt’02) as a tool to construct efficient IND-CCA secure encryption schemes. Since then, SPHFs have been used in various applications, including password authenticated key exchange, oblivious transfer, and zero-knowledge arguments. What makes SPHFs so interesting and powerful is that they can be seen as implicit proofs of membership for certain languages. As a result, by extending the family of languages that they can handle, one often obtains new applications or new ways to understand existent schemes. In this paper, we show how to construct SPHFs for the disjunction of languages defined generically over cyclic, bilinear, and multilinear groups. Among other applications, this enables us to construct the most efficient one-time simulation-sound (quasi-adaptive) non-interactive zero-knowledge arguments for linear languages over cyclic groups, and the first one-round group password-authenticated key exchange without random oracles.
Benoît Libert, Thomas Peters, Marc Jóye, Moti Yung
No abstract is available for this record.
Bingshuang Liang
This paper takes the architectural historical relics in the city of Dazhou as an example.With the applying of technologies of AS2 SH and Web3 D,and adopting the improved five-layer architecture model,the digital information platform for immovable historical relics was developed successfully,which on the one hand,improved current means and ways in historical relics survey,management and protection,on the other hand,achieved high efficiency,normalization and modernization.The actual development indicates the platform performed well in expansibility,maintenance and portability.Besides,pretty feedbacks from users on the platform,and achieves expected goal.
Da Cheng
To realize the digitalization and visualization of road achives,this paper presents the MVCPF plug-in framework which is based on MVC Design Pattern and modularization programming method.According to the single responsibility principle,application is divided into some plug-in modules which follow MVC mode.Modules that stand apart from each other can be integrated as a whole by using message response and data share of MVC.Based of that,R-Trees is used to create a spatial index for the data,and achieve an efficient management of huge amounts of data,achieve in quick query of information in 3Dscene;road web3 Darchives MIS is designed out which has the characteristics of a clear structure,small size,scalability,etc.It is easy to be published,updated and expanded.The huge road 3Dscene,which contains terrain,road and attached facility models,can be transported and rendered as fast as possible.In addition,the achive information can be obtained realtimely in the web3 Dscene.
Jurate Silinskyte
No abstract is available for this record.
P. Carl Mullan
Bitcoin was created as an electronic version of cash. The decentralized currency is revolutionary for its use of a distributed ledger. Rather than a central ledger held by a third party requiring trust of that third party, Bitcoin distributes that ledger to all users and removes the need for a third-party intermediary. Bitcoin is becoming “money without banks” for many users. It is difficult, but not impossible, for regulatory agencies to monitor Bitcoin activity. These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.
Rafael Delfin-Vidal, Guillermo Romero-Meléndez
No abstract is available for this record.
Chen Zhao
This thesis illustrates forensic research work on Bitcoin, an innovative Internet based global transaction system that attracts ascending popularity during the recent few years. As an open, public and scalable distributed payment system, Bitcoin brings forward significant economic and technological impact to our world. Meanwhile, a new notion of virtual currency, "Bitcoin" comes into existence such that Bitcoin currency can be "mined" from all over world complying with specific algorithms. Mined bit "coins" has practical monetary values that turn the Bitcoin system into a digital currency circulation system. Due to Bitcoin's decentralized semantics, Bitcoin transaction and currency are not subject to control and censorship from any single authority. Therefore, Bitcoin brings out various security concerns about its application as a long-term reliable system.\nThe research in the thesis focuses on forensic study on Bitcoin. It covers experimental study on the Bitcoin network as a peer-to-peer system and a graph-based forensic approach against Bitcoin's transaction data. Major contributions include network data evaluation and transaction history analysis. In case of forensic investigation is needed against criminal incidents such as fraud, false transactions and money theft, which are commonly seen in commonly used digital payment systems, the research provides a guidance of efficient information collection and framework of evidence data processing and extraction
Thomas W. Slattery
No abstract is available for this record.
Mattia Bongini, Massimo Fornasier, ,Technische Universität München, Facultät Mathematik, Boltzmannstrasse 3, D-85748, Garching bei München
Conditional self-organization and pattern-formation are relevant phenomena arising in biological, social, and economical contexts, and received a growing attention in recent years in mathematical modeling. An important issue related to <em> optimal government strategies</em> is how to design external parsimonious interventions, aiming at enforcing systems to converge to specific patterns. This is in contrast to other models where the players of the systems are allowed to interact <em> freely</em> and are supposed autonomously, either by game rules or by embedded decentralized feedback control rules, to converge to patterns. In this paper we tackle the problem of designing optimal centralized feedback controls for systems of moving particles, subject to mutual attraction and repulsion forces, and friction. Under certain conditions on the attraction and repulsion forces, if the total energy of the system, composed of the sum of its kinetic and potential parts, is below a certain critical threshold, then such systems are known to converge autonomously to the stable configuration of keeping confined and collision avoiding in space, uniformly in time. If the energy is above such a critical level, then the space coherence can be lost. We show that in the latter situation of lost self-organization, one can nevertheless steer the system to return to stable energy levels by feedback controls defined as the minimizers of a certain functional with $l_1$-norm penalty and constraints. Additionally we show that the optimal strategy in this class of controls is necessarily <em> sparse</em>, i.e., the control acts on at most one agent at each time. This is another remarkable example of how <em> homophilious</em> systems, i.e., systems where agents tend to be strongly more influenced by near agents than far ones, are naturally prone to sparse stabilization, explaining the effectiveness of parsimonious interventions of governments in societies.
Jiang Wen-hon
The basic concepts and features of Web3 D technology are introduced and four kinds of commonly used Web3 D technologies are reviewed. Then the method of application and development process of Cult3 D are summarized,and the applications of Web3 D technology in the teaching of civil engineering specialty are explicated by an example,so as to provide some reference.
Nicole D. Swartz
No abstract is available for this record.
Jamal Bouoiyour, Refk Selmi, Aviral Kumar Tiwari
The present study addresses one of the most problematic phenomena: Bitcoin price. We explore the Granger causality for two relationships (Bitcoin price and transactions; Bitcoin price and investors’ attractiveness) from a frequency domain perspective using Breitung and Candelon’s (2006) approach. Intuitively, this research gauges empirically the causal links between these variables unconditionally on the one hand and conditionally to the Chinese stock market and the processing power of Bitcoin network on the other hand. The observed outcomes reveal some differences with respect to the frequencies involved, highlighting the complexity of assessing what Bitcoin looks like and the difficulty to gain clearer insights into this nascent crypto-currency. Beyond the nuances of short-, medium- and long-run frequencies, this paper confirms the extremely speculative nature of Bitcoin without neglecting its usefulness in economic reasons (trade transactions). The consideration of the Chinese market index and the hash rate has led to solid and unambiguous findings connecting further Bitcoin to speculation.