Blockchain Papers

Craig Gentry, Jens Groth, Yuval Ishai, Chris Peikert · 6 authors

No abstract is available for this record.

Xiaochao Qian

We give an explicit definition of decentralization and show you that\ndecentralization is almost impossible for the current stage and Bitcoin is the\nfirst truly noncentralized currency in the currency history. We propose a new\nframework of noncentralized cryptocurrency system with an assumption of the\nexistence of a weak adversary for a bank alliance. It abandons the mining\nprocess and blockchain, and removes history transactions from data\nsynchronization. We propose a consensus algorithm named Converged Consensus for\na noncentralized cryptocurrency system.\n

Rasudin Rasudin

Permasalahan lambatnya akses Internet client terjadi ketika mengakses Internet secara bersamaan, akibat distribusi bandwidth yang tidak merata oleh pengguna yang melakukan aktivitas download dan upload. Pengertian Quality of Service (QoS) adalah kemampuan suatu jaringan untuk menyediakan layanan yang baik dengan menyediakan bandwidth. Tujuan saya menggunakan metode Hierarchy Token Bucket pada DD-WRT untuk mengatur kecepatan Upload dan download pada masing-masing alamat IP client secara sentralisasi menggunakan firmware dd-wrt. Dengan demikian jika ada client yang mengakses internet membutuhkan kapasitas bandwidth yang besar, maka client lain tidak akan terganggu, karena masing-masing sudah mempunyai kapasitas bandwidth yang dipakai untuk mengakses internet.

Patrick Delorme

Yiannis Sakellaridis and Akshay Venkathesh have determined, when the group\n$G$ is split and the field $\\F$ is of characteristic zero, the Plancherel\nformula for any spherical space $X$ for $G$ modulo the knowledge of the\ndiscrete spectrum.\n The starting point is the determination of good neighborhoods at infinity of\n$X/J$, where $J$ is a small compact open subgroup of $G$. These neighborhoods\nare related to "boundary degenerations" of $X$. The proof of their existence is\nmade by using wonderful compactifications.\n In this article we will show the existence of such neighborhoods assuming\nthat $\\F$ is of characteristic different from 2 and $X$ is symmetric. In\nparticular, one does not assume that $G$ is split. Our main tools are the\nCartan decomposition of Benoist and Oh, our previous definition of the constant\nterm and asymptotic properties of Eisenstein integrals due to Nathalie Lagier .\n Once the existence of these neighborhoods at infinity of $X$ is established,\nthe analog of the work of Sakellaridis and Venkatesh is straightforward and\nleads to the Plancherel formula for $X$.\n

Malte Harder

From a visual standpoint it is often easy to point out whether a system is considered to be self-organizing or not, though a quantitative approach would be more helpful. Information theory, as introduced by Shannon, provides the right tools not only quantify self-organization, but also to investigate it in relation to the information processing performed by individual agents within a collective. This thesis sets out to introduce methods to quantify spatial self-organization in collective systems in the continuous domain as a means to investigate morphogenetic processes. In biology, morphogenesis denotes the development of shapes and form, for example embryos, organs or limbs. Here, I will introduce methods to quantitatively investigate shape formation in stochastic particle systems. In living organisms, self-organization, like the development of an embryo, is a guided process, predetermined by the genetic code, but executed in an autonomous decentralized fashion. Information is processed by the individual agents (e.g. cells) engaged in this process. Hence, information theory can be deployed to study such processes and connect self-organization and information processing. The existing concepts of observer based self-organization and relevant information will be used to devise a framework for the investigation of guided spatial self-organization. Furthermore, local information transfer plays an important role for processes of self-organization. In this context, the concept of synergy has been getting a lot attention lately. Synergy is a formalization of the idea that for some systems the whole is more than the sum of its parts and it is assumed that it plays an important role in self-organization, learning and decision making processes. In this thesis, a novel measure of synergy will be introduced, that addresses some of the theoretical problems that earlier approaches posed.

Wolfgang Johannsen

BIOLOGY has evidently borrowed the terms “heredity” and “inheritance” from everyday language, in which the meaning of these words is the “transmission” of money or things, rights or duties—or even ideas and knowledge —from one person to another or to some others: the “heirs” or “inheritors.” The transmission of properties—these may be things owned or peculiar qualities—from parents to their children, or from more or less remote ancestors to their descendants, has been regarded as the essential point in the discussion of heredity, in biology as in jurisprudence. Here we have nothing to do with the latter; as to biology, the students of this science have again and again tried to conceive or “explain” the presumed transmission of general or peculiar characters and qualities “inherited” from parents or more remote ancestors. The view of natural inheritance as realized by an act of transmission, viz., the transmission of the parent's (or ancestor's) personal qualities to the progeny, is the most naive and oldest conception of heredity. We find it clearly developed by Hippocrates, who suggested that the different parts of the body may produce substances which join in the sexual organs, where reproductive matter is formed. Darwin's hypothesis of “pangenesis” is in this point very consistent with the Hippocratic view, the personal qualities of the parent or the ancestor in question being the heritage. Also the Lamarckian view as to the heredity of “acquired characters” is in accordance with those old conceptions. The current popular definition of heredity as a certain degree of resemblance between parents and offspring, or, generally speaking, between ancestors and descendants, bears the stamp of the same conceptions, and so do the modern “biometrical” definitions of heredity, e.g., as “the degree of correlation between the abmodality of parent and offspring.” In all these cases we meet with the conception that the personal qualities of any individual organism are the true heritable elements or traits! This may be characterized as the “transmission-conception” of heredity or as the view of apparent heredity. Only superficial instruction can be gained by working on this basis. Certainly, medical and biological statisticians have in modern times been able to make elaborate statements of great interest for insurance purposes, for the “eugenics-movement” and so on. But no profound insight into the biological problem of heredity can be gained on this basis, for the transmission-conception of heredity represents exactly the reverse of the real facts, just as the famous Stahlian theory of “phlogiston” was an expression diametrically opposite to the chemical reality. The personal qualities of any individual organism do not at all cause the qualities of its offspring; but the qualities of both ancestor and descendant are in quite the same manner determined by the nature of the “sexual substances”—i.e., the gametes—from which they have developed. Personal qualities are then the reactions of the gametes joining to form a zygote; but the nature of the gametes is not determined by the personal qualities of the parents or ancestors in question. This is the modern view of heredity. The main result of all true analytical experiments in questions concerning genetics is the of the transmission-conception of heredity, and the different of as as have in that to the same point of view, the as we may the conception of heredity just Here we can not the of the ideas concerning heredity, not even in the but it be as a that a very great of the terms by the modern biological have been the of the and that the of and are not from that old may be words as “transmission” and The science of genetics is in a an science just as the in the times of who the an in chemical The as have the modern view of heredity, not from the old “transmission-conception” as but it from the of and who with more or less tried to the the great of the for the in of more in of and in of but have suggested that the elements for inheritance elements of or of the different or of the individual from the in question. has an elaborate hypothesis of heredity, that of the are of in the of a in the of a being in some the of an or a of that in the to organs, and that of the are of parts of the inheritance in question are the or ideas may have some interest as of the but they have no in the of is evidently the a view of heredity any The of the by and but as an expression of the insight by and is in the degree a all the of and it may is a that is not we to even to but that it may be by of the to the current This is the it is to a in all cases where or are being developed. terms are by their in or and from which they of not to the have the terms and and some as and to be in the science of The is nothing but a very with and it may be as an expression for the or in the by modern is the of all the in a or in a a is by the of this is in one point and the of the gametes in question in one point from to the nature of the it is as of no to any but that the a is from The have the great of being in their In accordance with this quite natural the of the may be to the of the We do not a but we are able to or in these the and The very by as may be with in so as the is the of the of the in question. these are is by the as of The the and the in the of the individual the organism is a and its reactions are determined by its with the of all may it be or the is with the The can be by the qualities and reactions of the in question. that some of are different then these produce more or less as to the personal qualities of the individual of of different it be quite to they have or have not the same we to be We may find that the in question so that they to the same the current of this or we may in cases that they a so that or more different may be of by or by of or may be characterized as are real the or of are again and again the for in the are and the of the of as to and characters of the has been the of natural which was a science of by the of the has of with in its concerning The of by from one to another have and the of are the in very but that is an point may be in one which the the view the of the in different are the main and the transmission-conception we may this conception as a in to the the has been gained in and The to an of the or the may an of the of the The of has its most in all where the are where with the or by to one this being characterized by the of the of any of and so This is to the all between the different in question the of and and have the point for as a of may be as the from one by is a nothing as to the qualities of the in question. to be (or even the of a of can be as as are very of be quite in and in to one and the same the was but The of the is a main point in the of of nature is not at all a for the of with is the of which the of have some The of from has been the for the that is not able to the nature of The of the of a by from to in the by the to the a of in the a great of those is for the of the of any be for the result of the no or have been at a in which is no as to the in have no This result has in been by in Here may the experiments of with experiments which have been quite of and which have been of great for the and of the The of these experiments has been on the that the but this matter to of no in the The that of and of in the of as a is a of the Also experiments with the of and the of as to may be as for this has at the same as to the by The famous of and its by to have the of in by the of the of in these of correlation have been in their of may be in but they have nothing at all to do with genetics or general are for insight into the nature of heredity. to heredity, it is a expression for a The are the in but generally the in is In no of the can be all of the as to the of and may even a that the is in in heredity speaking, a of the “transmission-conception” and nothing The characters of ancestors as as of are both in quite the same manner reactions of the of the gametes in question. between an ancestor and one or more of as heredity is in the as we have to the is not a of the personal of any The of a or a may be with a This in of its realized but not in of the of its it may be with the of gametes and its is its which are determined by its In the in are in of are The it is to by of any individual the to which it the the as as in the no The is an view of the reactions of as as true heredity is This view is an to the chemical view, as chemical have no is and in the same may be the of its or the of its that it is to this of heredity in its to the to the of we meet with true viz., the of and all of is a very great but is quite different from heredity. may be of and the of is not an is in to as of some of or in their of the of from more Certainly, of of and of all on by of with the not the but their But all this has nothing at all to do with the biological of heredity. is of to that the of by has in but this nothing as to for which is The very form of the may be to be in all its in cases of experiments in In nature and even in the chemical the chemical are not to be in quite The of a may be by to the with the we the question the of a may not be by some or from the individual organism in which the was developed. Here we meet with the cases of heredity, e.g., the of the gametes or as may be in certain cases of and of heredity may have the of or but they do not at all with the of heredity. In cases as that by viz., the “heredity” of a form of by “transmission” the of the not this may at the be as we have to do with a of the or the in and that may be the for the of heredity the which no or a The of being as quite it may be very to clearly from determined which the form of heredity both and The and not to be in with of any may be to in the and consistent of the that may be characterized as by or it be that as as are no between and of is but not is a The of or, is of for the question of the inheritance of “acquired and are in the most both the of the with the the with the of the of the in question. The of with and the experiments of that of the are by as no with has any for the Lamarckian view, the most to the experiments by for the of their have not but have the of some by and are at the same the in personal qualities being to the in are their of it is that their in biology as ideas has been most some cases of apparent of may have with Lamarckian e.g., of by as “the that has of the was that with analytical that has the great But at the the from the is in on the of for are for the the that the was not at all the of to point the of as to the of in The and more the The of or of in may be for the of not to we have an times by viz., the of with as it has been that we have the essential The in have been the the been from the and to the result be a of the those The to to no for the The are a to of with and in the of this are to any questions of and they make as to the nature of heredity and has the of as a be an in heredity. to the of it has been by e.g., that is a old and This is quite not in a manner the of but even tried a to But it can not be that the of as a true analytical as an of in as a at any and of a from this analytical been in the times of or it even been in by the the real of have been by the of The may then be characterized as and may to a certain with the most of of with a of for a a we may even that the may be as of the or ideas may as be but they are by the of The of a in question is the conception at by and is a between different This has been by may be as an In very on experiments with as that was as a of of and experiments to the Lamarckian view have as even these may be as all the of experiments is in quite in of But we in and that for a of the the is a The of in question is to this can not statements just as to their but accordance with conception the famous words from the be from and some very of have the for the is that we different as different in This is an essential but no in the to that view be In a very manner be for are the in the degree or of any as it different e.g., the of by and may be very as of the of the in and they a in The of the in question between the but this is not the e.g., with or even with very some of the are the between the may or may even with of as to the in the and is no as to their But that these are with the of between the to have the the of the the reactions of the may different all of or has nothing at all to do with or of of genetics to some may to has great the of in all of from to may be with different in of the to not from that be of may in one be different in e.g., the of the that of In another may or their may be of may produce and it is to that some of on the reverse is realized on In of both characterized by a degree of to produce in the the in of The are the of the in as as in the just are of just as as the of different chemical as to chemical it may be to that different chemical or of which are to be and may quite to point the of for different of and in different or in with The essential point in the matter of that a in the same manner all chemical or in as in chemical or are not to at less to do so in the same all even quite may be for the of as some are to a This is a in as in the of has the of this point for the the of as to the and are a of the and we find in current this of with and we even have with the that the of a may in in different or but that in they into one In this of the of the in a is that view has been by in this but be in the is not for an to with questions of and between the are the of and the of and is We have with some of the it is to at The of this of has an of and cases that at with the have been more on a and have quite in accordance with The of a of this of it may be that the most of the essential point in the of the personal in heredity. the same it the of as being by the of the that the personal qualities of the organism in are the of the reactions of the The of one of may have the the of for any to be even in cases where no of to as to the cases of it is not to of the in the or for their and being reactions of that may have in the be a of to the of different as as Here we meet with the questions of correlation and of can not into a discussion as to the of with its in a discussion is to be may point that cases of presumed correlation may be cases of or more characters to the even one The and even the that they are reactions of different The of and as to the are in some with of correlation and of The discussion of the for and as to may the of may be has in as to in a of the the of we an between the of and the the in manner may be able to of the the main of the a on this it may be suggested that the or of a may be more to from its the from the of the may be of any as working as to the of is the nature of these can not as a discussion be in that the is and and even have this the in their and has clearly that it may be quite to a is to or to the of a in the that can as be determined in this by is the of between the gametes a may be The facts, that a may be in some but in and that in different cases may be very that are The famous of as to the form of may be as an In the is in it is and in both cases the one has that is a of and from in one as with But from in with as in and in the with this it is as not to or is the form of for the of which the of are to be the most is the most may even be an expression for a of in the The of the by in all cases be and it is quite to that the of the in are in cases in but in as to with chemical reactions it be in that a may be the of of any as as the of any in the in question. The elaborate of of has very and the most is the most of any in question. The or in are quite the of in the it may be that for one may be elements for the of quite this be the then the of characterized by the of in the of different able to may be by a in which be any is no to that the the of into The of by of the of are a of interest in this to cases of in which and do not the it at be that some apparent are by of the for The experiments of and have to that may and be or as to the of the is no for or In inheritance we meet with of the same nature as in the of as the for the more or less of the different of in may the as has in cases the different degree of with which the of gametes is realized may the of in the as has Here we can not the in a of the a of concerning this Only one of may be viz., the to or In cases of inheritance the in question be to by the act of or, in accordance with the and the to the in some manner be In this which is very with the conception of as be of to be in the of the modern some cases in the of as to the of to be a the insight by experiments as as by concerning the of has the question in a The of and have to quite as to the of In cases no is no is in cases is no for any or of as to this has the in question. But cases of these as to the of the of are the most and most has in a and manner that the in with the be of cases to these and gained an with and was in But even this may with The for is has clearly of the concerning the of the with the of the of that of and in is a The is determined by different in the same and the of by and of these a of in be these the of the in question. we have to and we for the the which is between as and as in of no a as an and it is not to find that the of the of the be the of the so it is in the of experiments with as has clearly of heredity in concerning both and may be with in question. in that certain in for the view that we have no inheritance but true as as in the cases of as we may in the cases of may then in a more manner the true nature of the apparent in as we can that this not with be in that have been very between the in these experiments are with great and parts of the those may have can not be to it is that in may have great the and in a which into and to be into has a very the and form of the in question. Here are not the the of viz., that or characters may be determined by different and that one of may have different it that is in a very but may be even very for this the may be into But is to do in the as as to the is as the of be a with But all the of the of do not as to to the that the of and so on may be regarded as or of the and of all things in the as their This view is even in those cases where can be In the discussion as to the of true the have of a as characters of in cases where the elements of the in question are as it may be is not at all for the of But the of for is quite different from the that elements have for the of heredity. The question of as the presumed of to be an not able to any for “the of the in the The organism is in its and by its parts of the individual are as to In has been no as to this and as to has for a the same view the of and who have suggested that is determined or at any by a of the we the in the of the The of and the of parts in the individual may their the of the But these as a not or the of the in question. on we the problem of by Here we have to point the that with a more those substances or the reactions of which we of characterized by the of The of the of their to that this as as the and of in the some of the of The discussion of to the question of or In the of modern of presumed of in e.g., as to in But more analytical experiments have in cases in the the characters in question to be more reactions at has the question in a quite a working the be not of but of the gametes as a not be as the by of the of a with be of of the that this be able to “the of so with in and so or by Here we again the question of that the by and are more consistent with the real nature of the in question. the has not been able to that cases of are of but even the as to in and by as a not to any real for cases as has viz., nature being for in some may at the of being to or to different of in the in question. But a to the real of The very of as to the of certain characters in have clearly a or a in of any be in that a of are in and these concerning all and a to the of all it be suggested that in parts of the some of may or even the of which the The to be to the of by e.g., the of and of Here we the of in or with so by be a for the of the in e.g., for the nature of the of the (or for the in not be produce at are to point that may have a as to but that this question is in of the problem of or may be but the in modern genetics in the of as the we the of as an essential for the of matter in and for the or of we in of to find in the of and the of the and in be But this is not the The experiments of in a manner the of in the a degree of and in things it we may in modern genetics be of the and of that things in nature may be and the in heredity we may the in nature as as in more of the famous of and the of to the modern of and all as to point the of the in question. Here we not the it is to that the essential point is the or of of the The experiments of as to have in the most manner that the which produce the in this viz., the and of are able to act in a manner the of the and has the of in with the may in some cases be certain to be by but it is that in all is the in the of to the of which may the of of be that are from by in be with But is no for this in the between the in characters may be a of as it be is not at all with has the between the of in and in and as the in nature have all as in experiments with The chemical to may be the of and so on. The may be by more But are of very for the of The by the great of experiments as to and not personal as a of any as by and been are meaning from point of of characters gained to an of and the may the of as to may be as to the old question of this problem in the famous cases of has in a most manner been into terms by the and experiments of and This of the and has been for for the The not to a true or of heredity, but may be regarded as an for an that in its may be to be and even all may some to But as it to be the most in may then be as the of in ancestors and descendants, or, as in accordance with this heredity for those of the that find their expression in the and developed it is to this for its real but for the and of the great problem of heredity. In this the of famous as in as in has been the for the and the old in This is a in the of the of it at and to ideas of and in and a great of the of But just these qualities have the of for the analytical of modern which has in a true in

Stan Cristian, Manea Adriana Denisa

The specifics of contemporary society involve, at the level of educational sciences, both epistemological adjustments as well as adjustments in the relations of the school as an institution with the governing authority. Reduction of the state's involvement in the organization and operation of the school implies, alongside decentralization and the reduction of allocated budgetary resources, both the assumption of the principle of self-financing by the various educational institutions and the concern for competitiveness as a prerequisite for survival in the conditions of a competitive type of educational reality. Schools thus become competitors in the field of educational offers, beneficiaries of the education system become consumers in the educational market and the orientation of the marketing activity towards increasing institutional visibility constitutes one of the basic conditions for success.

Olivier Coutu

Dans les crypto-monnaies telles Bitcoin, l’anonymité des utilisateurs peut être compromise de plusieurs façons. Dans ce mémoire, nous effectuons une revue de littérature et une classification des différents protocoles existants pour anonymiser les usagers et analysons leur efficacité. S’appuyant sur certains critères désirables dans de tels protocoles, nous proposons un modèle de mixeur synchrone décentralisé. Nous avons ciblé deux approches qui s’inscrivent dans ce modèle, le plan de transaction et le réseau de transactions, le second étant une contribution originale de ce mémoire. Nous expliquons son fonctionnement puis analysons son efficacité dans le contexte actuel d’utilisation de Bitcoin

Hsihui Chang, Christopher D. Ittner, Michael Paz

ABSTRACT This study focuses on three broad Finance organization roles: reporting, compliance, and internal control/risk management (RCCR); performance management; and strategic partner. Using data from a global survey of 832 firms, we examine the determinants of the various roles' importance and their relation with Finance effectiveness. While the effects of organizational change, market growth, international operations, firm size, decentralization, and industry on Finance responsibilities vary depending upon the role, we find little evidence of tradeoffs between the various roles. Instead, we find evidence of complementarities between roles, whereby greater emphasis on one role is associated with greater Finance effectiveness in the other roles. Additionally, we find that information system integration (ISI) not only has a positive direct impact on effectiveness in all three roles, but also interacts with the importance placed on RCCR and performance management roles to improve the Finance organization's effectiveness at carrying out these responsibilities.

Hong‐Seok Park, Ngoc-Hien Tran

Smart manufacturing (SM) considered as a new trend of modern manufacturing helps to meet objectives associated with the productivity, quality, cost and competiveness. It is characterized by decentralized, distributed, networked compositions of autonomous systems. The model of SM is inherited from the organization of the living systems in biology and nature such as ant colony, school of fish, bee’s foraging behaviors, and so on. In which, the resources of the manufacturing system are considered as biological organisms, which are autonomous entities so that the manufacturing system has the advanced characteristics inspired from biology such as selfadaptation, self-diagnosis, and self-healing. To prove this concept, a cloud machining system is considered as research object in which internet of things and cloud computing are used to integrate, organize and allocate the machining resources. Artificial life tools are used for cooperation among autonomous elements in the cloud machining system.

Niels Vandezande

With the increasing use of virtual currencies such as bitcoin, tax officials have started paying attention. Privacy and virtual identity specialist Niels Vandezande of the Interdisciplinary Centre for Law and ICT (ICRI) at the KU Leuven – University of Leuven explains the implications of the recent IRS ruling on Bitcoin in the US, arguing that it may undermine the core reasons such virtual currencies were created.

Adam Mateusz Suchecki

Decentralization of public finance in Poland was an important element of changes in the political system of the country. As a result, some tasks of the state were transferred to the local government level. The Public Finance Act of 2009 introduced new public management methods, such as the performance-based budget and the long-term financial forecast, to the local government finance management. The purpose of this paper was to analyse the budget expenses on cultural tasks incurred by local government units in Poland in the years 2003- 2010 and the impact of the attempted application of the performance budgeting method to local government expenses relating to this field of economy.

Soňa Čapková, Lucia Roncakova

The year 2013 is already the ninth year of implementing fiscal decentralization in the Slovak Republic. The aim was to ensure independence as well as responsibility of subnational governments and improve the ability to finance their original competences from own sources. As decentralization leads to growth of imbalance intergovernmental transfers are the instruments used by central government to reduce fiscal disparities and fill the gap between the spending needs and fiscal capacity of some local authorities. Tax sharing system in Slovakia, is an important tool of horizontal fiscal imbalance equalisation. Despite the title, shared taxes play the role of unconditional grants if even they are formally labelled as local government own revenues under current legislation. In this paper we examine the allocation of personal income tax share as an instrument of regional policy and factors affecting interregional disparities in Slovakia. The paper presents some results of the research project VEGA1/0822/11 Redistribution of financial resources in the decentralized fiscal system in Slovakia.

Stefan Bornholdt, Kim Sneppen

Bitcoins have emerged as a possible competitor to usual currencies, but other\ncrypto-currencies have likewise appeared as competitors to the Bitcoin\ncurrency. The expanding market of crypto-currencies now involves capital\nequivalent to $10^{10}$ US Dollars, providing academia with an unusual\nopportunity to study the emergence of value. Here we show that the Bitcoin\ncurrency in itself is not special, but may rather be understood as the\ncontemporary dominating crypto-currency that may well be replaced by other\ncurrencies. We suggest that perception of value in a social system is generated\nby a voter-like dynamics, where fashions form and disperse even in the case\nwhere information is only exchanged on a pairwise basis between agents.\n

Tetsuya Saito

This paper considers whether the stability of Bitcoin in the market as a method of payment using a dual currency money-search model. In the model, there is traditional money and Bitcoin. The two currencies are classified by the storage cost and the probability that sellers accept particular money for payments. Agents are randomly matched for transactions. To consider substitution effect between monies, we allow new entries every period. In the beginning of each period, new entrants come into the matching process with a unit of money of their choice. A certain number of sellers also come into the same process to maintain the population share of sellers at a constant level. With appropriately chosen parameters, the author finds that there can be stable and unstable equilibria of the share of bitcoiners. In this case, a stable equilibrium is a success (bitcoiners take a large share) while the other (unstable) is a failure (bitcoiners take a marginal share or vanish). However, if the inflation rate of traditional money decreases, the successful equilibrium disappears to start approaching the failure even if Bitcoin is currently widely accepted. Furthermore, welfare comparisons suggest that an increase in the share of bitcoiners has a negative effect; hence, the benefit from reductions in the transaction costs must compensate for the welfare erosion if Bitcoin is accepted as a new kind of payment system. If the author is to succeed, the Bitcoin community or the public authorities need to be prepared for protecting the system from several illicit activities.

Frank Moosig, Julia U. Holle

New British Society for Rheumatology guideline for the treatment of ANCA vasculitis This article refers to BSR and BHPR guideline for the management of adults with ANCA associated vasculitis, by E. Ntatsaki et al., doi:10.1093/rheumatology/ket445, on pages 2306–09. In this issue of the journal an expert panel from the British Society for Rheumatology (BSR) presents an update of the 2007 BSR guideline for the treatment of ANCA-associated vasculitides (AAVs) [1]. It is remarkable that in recent years enough new evidence has accumulated to call for a revision of these recommendations, in particular because it is still challenging to conduct well-designed trials in these rare conditions. Many of the authors of the guideline have contributed significantly to the field. The British vasculitis scene belongs to the most active and productive groups worldwide and is a key part of the European Vasculitis Society (EUVAS). The guideline reflects the rapidly increasing evidence from controlled trials available in the past years and now includes biologicals [namely rituximab (RTX)] as a mainstay of treatment. The Rituximab versus Cyclophosphamide in ANCA-associated Vasculitis (RITUXVAS) EUVAS trial initiated by British vasculitis experts was one of the landmark studies in this context [2]. A milestone in 2013 was the approval of RTX for the treatment of AAV. This represents the first formal drug approval for AAV by the European Medicines Agency (EMA) in more than 40 years. Accordingly, questions concerning the appropriate use of RTX are among the most prominently discussed issues in this well-structured and straightforward guideline. Despite of the significant accrual of knowledge in recent years, the guideline also reflects that we still have to face a lot of uncertainty in the treatment of AAV patients. The guideline [1] refers to patients with disease consistent with the 2012 Chapel Hill Consensus Conference definitions [3] and thereby formally excludes a significant proportion of AAV patients. This underlines the urgent need for real diagnostic, not just classification, criteria. The ongoing EUVAS/ACR study for the development of diagnostic and classification criteria for primary vasculitis will probably establish such standards. Other definitions need international harmonization in order to increase the comparability of reported data. The present guideline defines remission as BVAS ≤1 and a daily prednisolone dose of ≤10 mg for at least 6 months. The 2007 European League Against Rheumatism (EULAR) recommendations on clinical trials in AAV suggest a BVAS of zero and a prednisolone dose of ≤7.5 mg/day [4]. Several other definitions have been used in different trials and observational studies. Furthermore, the 6 month criterion for remission in the new BSR guideline [1] is problematic. The guideline recommends switching to maintenance therapy after successful induction of remission, after treatment with CYC for example. Strict compliance with the above-mentioned definition could lead to a therapeutic gap of several months or prolonged use of CYC, which clearly is not the intention of the authors. This illustrates the difficulty in defining clinically and scientifically meaningful endpoints. Other uncertainties pertain to drug treatment regimens per se. Although it is generally accepted that high-dose glucocorticoids are the mainstay of treatment, there is still a notable lack of proven information on dosing, tapering or duration of therapy. The availability of RTX for induction of remission in AAV represents a major progression. Drug approval in this case was granted on the basis of randomized controlled trials—the RAVE trial [5] and the RITUXVAS trial [2]. These studies helped to establish an alternative treatment to CYC, yet a lot of important questions remain unanswered, such as who is the ideal patient for treatment with RTX and who should still be treated with CYC? There is a consensus that when considering first-line treatment, RTX may be the better choice for younger patients in order to preserve fertility, an advantage of RTX. While this is mechanistically logical, it still lacks formal proof. The guideline also states that RTX may be preferred in patients at high risk of infections [1]. When looking at the data from RAVE [5, 6] and RITUXVAS [2], no clear superior treatment for patients at high risk of infection could be determined during the relatively short observational periods. Considering the treatment of CYC-refractory patients, the overwhelming consensus among experts that RTX should be the drug of first choice is contrasted by a prominent lack of sufficient data. Another ongoing controversy outlined in the guideline [1] is the use of RTX for maintenance of remission. According to some uncontrolled retrospective data (e.g. [7]) and the as yet unpublished results from the French MAINRITSAN trial, addressing repetitive RTX administration for maintenance, moderate repeated doses of RTX (0.5–1 g) given at relatively long intervals (4–6 months) seem to be a promising future option. Apart from proving that RTX represents an option for maintenance there is hope that it may even be superior to conventional standard maintenance treatment such as AZA. Finding the optimal dose in order to maintain maximum remission rates and to reduce potential side effects is another major issue for future research. The ongoing RITAZAREM study assessing RTX administered as a 1 g dose every 4 months vs standard AZA will help to answer these questions. When looking at distinct clinical situations in AAV, in many cases the evidence level is still that of case series. This is especially true for the rarest of the rare AVV entities, e.g. eosinophilic granulomatosis with polyangiitis (EGPA). The guideline, capturing the available data, mainly refers to GPA and microscopic polyangiitis, but not EGPA. When considering the sparse data on many of the relevant topics, this guideline [1] will be a most valuable aid for clinical decisions in daily work. The generation of further evidence from clinical trials will hopefully lead to an update of the EUVAS/EULAR 2009 [8] recommendations, making standardization of the diagnostic and classification standards a worthwhile future task of the EULAR/EUVAS. Disclosure statement: The authors have declared no conflicts of interest.

J.A. Bergstra, Peter Weijland

The question "what is Bitcoin" allows for many answers depending on the objectives aimed at when providing such answers. The question addressed in this paper is to determine a top-level classification, or type, for Bitcoin. We will classify Bitcoin as a system of type money-like informational commodity (MLIC).

Assaf Shomer

We calculate the probability of success of block-hiding mining strategies in Bitcoin-like networks. These strategies involve building a secret branch of the block-tree and publishing it opportunistically, aiming to replace the top of the main branch and rip the reward associated with the secretly mined blocks. We identify two types of block-hiding strategies and chart the parameter space where those are more beneficial than the standard mining strategy described in Nakamoto's paper. Our analysis suggests a generalization of the notion of the relative hashing power as a measure for a miner's influence on the network. Block-hiding strategies are beneficial only when this measure of influence exceeds a certain threshold.

Nakai, Takeshi, Shinagawa, Kazumasa

In this short note we show that the Bitcoin network can allow remote parties to gamble with their bitcoins by tossing a fair or biased coin, with no need for a trusted party, and without the possibility of extortion by dishonest parties who try to abort. The superfluousness of having a trusted party implies that there is no house edge, as is the case with centralized services that are supposed to generate a profit.

G DurgaPriya, Soma Prathibha

The cloud storage offers users with infrastructure flexibility, faster deployment of applications and data, cost control, adaptation of cloud resources to real needs, improved productivity, etc. Inspite of these advantageous factors, there are several deterrents to the widespread adoption of cloud computing remain. Among them, security towards the correctness of the outsourced data and issues of privacy lead a major role. In order to avoid security risk for the outsourced data, we propose the dynamic audit services that enables integrity verification of untrusted and outsourced storages. An interactive proof system (IPS) with the zero knowledge property is introduced to provide public auditability without downloading raw data and protect privacy of the data. In the proposed system data owner stores the large number of data in cloud after e encrypting the data with private key and also send public key to third party auditor (TPA) for auditing purpose. TPA in clouds and it's maintained by CSP. An Authorized Application (AA), which holds a data owners secret key (sk) and manipulate the outsourced data and update the associated IHT stored in TPA. Finally Cloud users access the services through the AA. Our system also provides secure auditing while the data owner outsourcing the data in the cloud. And after performing auditing operations, security solutions are enhanced for the purpose of detecting malicious users with the help of Certificate Authority.

Meni Rosenfeld

Bitcoin is the world's first decentralized digital currency. Its main technical innovation is the use of a blockchain and hash-based proof of work to synchronize transactions and prevent double-spending the currency. While the qualitative nature of this system is well understood, there is widespread confusion about its quantitative aspects and how they relate to attack vectors and their countermeasures. In this paper we take a look at the stochastic processes underlying typical attacks and their resulting probabilities of success.

Filippo Balestrieri, Bernardo A. Huberman

No abstract is available for this record.

Tracy Sanders

In 2009, an innovative form of digital currency premiered in the marketplace — Bitcoin. Bitcoin is a peer-to-peer payment network developed by Satoki Nakamoto (Nakamoto). Nakamoto created Bitcoin to be the ultimate digital currency, meaning no governmental oversight, central database, or tracking system. Bitcoin, a so-called “cryptocurrency,” is a digital currency with encrypted messages that are not accessible to third parties. Bitcoin is leading the cryptocurrency market with pioneering technology concepts such as limited distribution and secure information system.

Stergios Papantonis

The main goal of this work is the design and analysis of passive components employing metamaterial structures and in particular the wire medium metamaterial. Although there has been a lot of research interest in the physics of such metamaterial structures, there are not many resources available describing the behaviour of classical components, such as waveguides and cavity resonators, that are formed by metamaterials. Therefore, the aforementioned widely used devices, are realized with the deployment of the "Fakirs bed of nails" and their performance is analyzed. Our motivation is to expand existing analytical models and their applications to commonly used passive electromagnetic components, with a view to explore potentially new applications. As a means of study analytical techniques together with numerical simulations and measurements were used. This thesis is structured in the following chapters. The first chapter is an introduction to the basic principles of electromagnetics and their use on the framework of metamaterials; as illustrations some state of the art applications are presented. The next chapter is a literature review covering the work that has been done in the area of our main research interest (i.e., the Fakir's bed of nails as a metamaterial). An overview of the mathematics describing its behaviour is given as well as applications of the proposed structure. Attention has been paid on the latest studies because they provide complete physical insight. Some results from this chapter are used later as background knowledge for the analysis of passive components. This chapter is intended to lay the foundations for the reader to continue reading the rest of this work without the need to look in the literature. Chapter three investigates the dispersion effects in parallel-plate waveguides with both plates being realized by the Fakir's bed of nails. This chapter serves as an example as to how the Fakir's bed of nails can be used to form components. An analytical solution describing the behaviour of the waveguide is presented and compared against full wave numerical simulations. Chapter four presents a theoretical study of the resonant behaviour of metallic nanorods. A clear analogy between the coupled rods and the split rings/split squares is shown. The decline in the resonant frequency as the gap decreases, previously described in terms of self-capacitance, is interpreted by surface plasmons coupled across the gap. Chapter five presents a new enabling technology for implementing tunable rectangular waveguide components and circuits with the use of 2D and 3D metamaterials; a holey metal surface and wire media, respectively. As proof of concepts, results for tunable rectangular waveguide filters are presented with the use of pin block inductive irises and capacitive posts. Furthermore, by adapting the traditional metal-pipe rectangular waveguide for tunability, regions of the solid metal walls are replaced by holey metasurfaces. Prototype tunable structures were measured for verification and good agreement is achieved between full-wave numerical simulations and measurements. Chapter six analyzes a radically new design of waveguide verification device, suitable for measuring instruments such as Vector Network Analyzers. The device is designed to enable its roperties to be changed, by known amounts, after the device has been connected to the system that requires verification. The performance of the device is based on introducing relative changes in the transmitted and reflected signals and so is insensitive to errors introduced by waveguide flange imperfections. This makes the technique, in principle, ideally suited for waveguide VNAs operating at millimeter- and submillimeter-wave frequencies where these flange errors can dominate the measurements. A verification device is designed, simulated and tested in WR-15 waveguide (50-75 GHz). The last part of this thesis presents a rigorous analysis of lossy spherical cavity resonators starting from first principles. The electromagnetic field inside the spherical cavity is expanded in normal waveguide modes and the eigenfrequencies of the cavity resonator are obtained analytically by enforcing the appropriate boundary conditions at the cavity wall. Unlike perturbation techniques, used when low losses are present, there are no inherent limitations in the presented analysis and, therefore, its applicability range is much broader. Exact analytical results, acting as a benchmark reference standard, are compared to those generated independently by two commercial full-wave simulation software packages (HFSS and COMSOL). When the wall transforms from being a perfect electrical conductor to free space, as its intrinsic conductivity decreases from infinity to zero, it is found that the eigenmode solvers with both software packages increasingly fail. With both software packages, all possible modeling strategies have been investigated and their associated limitations identified. Moreover, a plane-wave approximation model is proposed that accurately predicts the numerical simulation results.