Blockchain Papers

Michael Ben-Or, Gutfreund

No abstract is available for this record.

Helga Cuéllar-Marchelli

No abstract is available for this record.

Daniel Verdier

The previous chapter established that centralized countries registered relatively high levels of financial agglomeration. Without regulatory and legislative power, local governments in centralized countries could not – nor did they want to – stop center banks from opening a branch on every local “Main Street.” The reasoning, however, rested on an autarkic model – one without an international dimension. This chapter brings the international dimension into the picture, asking whether it ran parallel to or mitigated the process of agglomeration at work in the domestic economy. Theory and historical evidence both suggest that internationalization happened simultaneously with agglomeration, and more markedly in centralized than in decentralized countries. Consider a country with two regions – the basic model of chapter 2. Graft onto it another country with a similar structure. Allow capital to flow freely between regions of a same country but not across countries. Burden the exchange of financial products with information asymmetry so that the losses incurred are lower between two financial cores than between a given core and a foreign periphery. The rationale for this differential in asymmetric information is that nineteenth-century foreign investors had an overwhelming preference for large, central, visible assets in foreign countries – mostly government bonds – over small, peripheral, and unfamiliar ones. It is reasonable to expect from such a model that the core–periphery pattern within a country and the degree of internationalization of the financial sector in that country would be mutually reinforcing.

S. A. K. Amer, V. Gopalan, T. C. Li, W. L. Ledger · 5 authors

No abstract is available for this record.

Geert Bekaert, Campbell R Harvey

No abstract is available for this record.

Paul Gootenberg

Cocaine has a long and mostly forgotten history, which more often than not over the past century has revolved around relationships between the United States and the Andean republic of Peru.1 This essay examines that U.S.-Peruvian axis, through three long historical arcs or processes that preceded— and in some sense inform—the hemispheric “drug wars” of the past twenty years. For each stage, I will focus on the changing U.S. influences, signals, or designs around Andean coca and cocaine, the global contexts and competing cocaine circuits that mediated those transnational forces and flows, and the notably dynamic Peruvian responses to North American drug challenges. Each period left its legacies, and paradoxes, for cocaine’s progressive definition as a global, illicit, and menacing drug.This is mainly a synthetic essay, trying to make sense of a vast body of new research in international archives—but the history of drugs also makes fertile ground for trying new methods or approaches from the historical social sciences. Two approaches are worth mentioning here. First, this essay draws on the “new international history,” which is working to overcome traditional academic dichotomies between domestic and foreign actors, dominant and dependent geographies of power, and between cultural and economic dimensions of transnational events and relationships. I thus hope to go behind and beyond standard diplomatic history narratives of “drug control.” Second, this essay shares broadly in what can be termed a political or social “constructionist” view of drug regimes, an approach with long roots in the field of drug studies. Not only official drug policies but our basic attitudes towards drugs (friend or foe, legal or illicit, domesticated or foreign), their variable social uses and bodily effects, and shifting patterns of supply and demand, are to a good degree historically created, conditioned, and changeable. Drug history, including that of cocaine, is about our protean social relationships to mind-altering substances, more than any rigid dictates of biochemistry or current morality.2The three phases explored in this cocaine genealogy are: (1) 1860–1910, an initial period that saw the promotion of hemispheric coca and cocaine networks and cooperation between the United States and Peru in making cocaine into a modern and global medical commodity; (2) 1910– 40, which constituted an era of transition in which the United States reversed itself and launched a domestic and worldwide crusade to banish the drug, while Peru exhibited greater autonomy, ambivalence, and cultural crisis towards its national coca and cocaine; and (3) 1940–80, when contemporary cocaine “prohibitions” came to fruition and a global reach, accompanied by a high degree of U.S.-Peruvian collaboration. But this final period and process also witnessed the creation of illicit international networks of the drug; with them, as we also see, were born the persisting and paradox-laden North American drug dilemmas of the late twentieth century.The half-century from 1860 to 1910 witnessed the erection of legal coca and cocaine networks linking the Andes to the United States and Europe. This era saw coca transformed from an exotic botanical rarity (in the West) and traditional indigenous herb (in the Andean highlands) into a modern global commodity and a staple of late-nineteenth-century medicine and culture. Yet by 1910, both cocaine and coca had become controversial and contested commodities, and the U.S.-Peruvian coca connection was riven with contradictions.Cocaine, first crystallized from Peruvian coca leaf by 1860, was widely regarded as the modern miracle alkaloid of the late nineteenth century. By 1900, the United States had emerged as the world’s largest consumer and promoter of coca and cocaine for a range of medical and popular uses. Coca leaf spread first, inspired by luxurious French wine tonics (such as Vin Mariani) and a growing public and scientific confidence in coca’s active energizing qualities. During the 1860s, leading American physicians, such as William S. Searle, traded notes and fresh coca samples with their Peruvian counterparts. Erythroxylon coca, a mild yet complex stimulant comparable to tea or coffee, became embraced therapeutically by a range of American “eclectic” herbal physicians and drug companies for the treatment of a broad range of ailments, real and imagined. Culturally, coca became the antidote for that most emblematic of Gilded-Age American conditions—“neurasthenia,” the chronic nervousness associated with “brain-workers,” fast-paced urbanity, and competitive modernity. By the 1890s, a large consumer market for coca products existed where none had before. Infused in countless health tonics and patent medicines of the era, North America’s love affair with coca became immortalized in Coca-Cola, concocted in Atlanta in 1886, and by 1900 already one of the most marketable commodities ever seen.3 By 1900, the United States imported 600– 1,000 (metric) tons of coca annually, mainly for this consumer market, and mainly from eastern Peru. One still feels the initial American enchantment with coca in Dr. W. Golden Mortimer’s classic of of of the coca’s was a modern medical the first drug came of medical in the of its Cocaine and and such as By the late of American physicians and research with cocaine and its in from to the of For a cocaine as a for a of bodily and for and U.S. and of became in cocaine to tons of by the of the about a of more more than by some of the in American such as William and William S. But also a of the effects, and by the and of of by had the uses of cocaine or United through a of and to Peruvian of coca with the the of North American and to Peruvian and U.S. and U.S. in the Andes to coca supply the coca and crisis of in with cocaine to their and coca and One in the to coca to termed as a for their the North America’s on a Andean to coca and indigenous coca the first of with the to or the United this as Peru of American the of making in coca was as into the U.S. by the late a of American cocaine political a U.S. that domestic of the drug over the Peruvian United was by the in with a and linking to the the Andes in and a long in coca, for an fresh Peruvian coca leaf the of to supply their where for its most active medical associated with the drug in the were Dr. (in and the and an was a of which its making cocaine its leading by the became the world’s cocaine and by 1900 into a to cocaine and popular Vin and the with also some Yet their more on coca and coca leaf and in products from to into Peru. cocaine and was a to one in to (in the of and a new cocaine the eastern of an active in in as as the French and in their launched botanical and for coca which were when with of by cocaine into this century. in the of legal Peruvian cocaine for imported mostly coca American as the to global cocaine the first international and responses to forces to the creation of modern cocaine as a global the late nineteenth century Peru was a and from the of its first of coca was long associated with traditional leaf by the Andean the was thus by the Yet by the 1860s, Peruvian and medical such as Dr. and Dr. to coca as a good and a by growing medical the the of the with a medical and for cocaine in with scientific and and research of of scientific on the inspired a and a of in the This the of Peruvian a on the official of Peruvian of the drug itself for not coca coca and the a range of to market coca as a good for the Peruvian coca be the or of the century. such as also saw cocaine as a as of were thus became the of not only coca, but also cocaine, to this market from the its around Cocaine on spread from to of the where coca the of the of and and Andean By 1900, the and of had emerged as the of legal Peruvian cocaine to the coca of the fertile in the Andean of the leaf became for cocaine a of coca into the to and for By 1900, the of the coca products leading some of coca to and more than tons of cocaine to and leaf became commodities on and which traditional and in an exotic of cocaine in Peru. about and This or to the illicit of the but was on for in medical legal in the than and 1900, some of most and this the and of the and the and of was one of and in for U.S. of the for to in cocaine in became an the of to drug drug and to and the were in Peruvian cocaine in the of was the Peruvian Cocaine became in Peru modern and with a national coca Coca the and Peru the and its with its new uses Andean first Cocaine of a century of a Peruvian botanical with of the for Peruvian and to such and 1900 a miracle in the with a of national when between 1900 and cocaine its from miracle to drug, from commodity to illicit its were was the working of global circuits of commodity the and the which was to be or American for coca leaf in U.S. on through of with Peru. Cocaine its as the modern global not only in its but in its cultural one its became in medical from a modern to an and from the hope of modern to the of our and One in this complex was that of popular and a domestic to by the and that cocaine, with in the United the most consumer of both substances, transformed into the world’s most and in what medical has as American with drugs as and For were to cocaine was a for to that to the high initial on the drug, as as the and in the 1910 to both in and bodily from a to than tons in medical by the of This era saw the first by the United to a global cocaine the networks and of Andean cocaine to American designs but as yet illicit the period also the of or of cocaine, the United States United States was the in most of cocaine’s as and or of the in the United States were and will be to one first from most American had in to of its real and and to the of and of cocaine and of the more menacing than and still often drug By cocaine also became the on while and or This was an of a classic drug of U.S. cocaine the by and medical such as the good to or the field of and to public in their U.S. had become a national of drugs and drug Cocaine also and or their new of and of American that as became cocaine, to from the in the and coca and the cocaine to crusade in a that itself of a with a to international of our cocaine to the first drug in coca came in the which cocaine of U.S. and of the of came into cocaine in the U.S. and its the in what one be cocaine a in cultural and but mainly to their of American into Cocaine to as came on and cocaine research with the medical or yet international of illicit cocaine emerged in to those that around or an drug, that from a and of the public health and is were and cocaine and by the cocaine was from of cocaine were in or of illicit came to and from Andean coca this a U.S. political of cocaine and first only and only imported and coca leaf to their and into was still in Peru in was to its and became a with U.S. drug in their and over the U.S. became to cocaine, which cocaine or and to By the late cocaine not as a to of the but as of what not to inspired the American to to the in not go beyond international not the U.S. cocaine and American to in that a of domestic cocaine by the the U.S. such as had in the as a American cocaine the of the of drug of the and for the in of coca’s in international are still and to the and of were to cocaine as to United as the for drug the that drugs a global the this the of in which had also a this U.S. in from that cocaine in and its in its was to that world’s largest cocaine and the with the for a of in countless of and from the were designs on and an national and American for real also from the that Peru and to By the its indigenous coca in international while Peru its to the and on on cocaine in global and the This a new cocaine in American through a more complex cocaine between 1910 and Two global cocaine the first the through the and (in the of a new circuits Peruvian coca their national by and for a between and the Andes as cocaine first with coca in the but Yet by the of modern and coca by more than 1,000 tons of leaf Andean coca from and cocaine as on became the world’s dominant and of the and a crisis of the became a of cocaine supply and with such legal market and with to of international cooperation in the to their cocaine in the late still coca in the and of leaf in its the the of this in an to and American its first coca on in by the late with leading national the was of three tons of cocaine a of official in a global commodity a of in and coca the were in of largest drug this cocaine which the by official drug and some of which or the the United States and the over any cocaine of its over cocaine, and legal the this the American to Peruvian cocaine was Yet one that the United States or its drug to had of the and its Andean to make its legal cocaine and from the new of international drug American of and of Peruvian the But than Peruvian cocaine as an by to more about through the of on and with their Peruvian counterparts. the U.S. in a of the cocaine and by the had drug in on was also a working their networks in Peru and were to the of the or in for of an coca was one initial for the of diplomatic to or such but the United States was not yet a this Peruvian cocaine into an crisis between 1910 and This crisis itself in some from but of a national legal cocaine an than national was to a of or and than a of of its 1900 to and for a Coca of had to with competing in the U.S. Coca and cocaine than of the domestic were in the national the coca was the market of Cocaine in from the itself on the of Peruvian in the to one a for new market the the field on the associated with I and the of the cocaine in the cocaine was not a cocaine this in both of the a of the international Peru in world’s and some of a were to a health and a for the cocaine the as had modern in Peru mainly medical and the new or on the good of the of long modern national the on coca that had the the Dr. a national coca as a of the and By the the became and with coca as a or of a by most By the a of Peruvian by and with American and with the of coca’s on and the the of Dr. and to this Yet modern cocaine was not a had ever in Peru cocaine to be as a good national to the and the to the cocaine to scientific for coca and to into a modern was to make cocaine for final medical for was this was still a Peruvian by and One public health Dr. of into a from to from the late to a of American that on cocaine in the had coca into the of Peruvian an Peruvian to and cocaine, one that its global to from their This a to U.S. drug international and a national of coca mainly in and as the this contested American on Peruvian and emerged from this period from 1910 to largest was the of the United States from a coca promoter to a global for a that from the or the United States in cocaine its were as a of but were by or the by coca international with the of cocaine networks in and such supply a of drug the was a growing between the of and the of modern cocaine, between and American between economic and the market of legal cocaine, and between U.S. and on had to But the largest global was the era that saw the of cocaine and active cocaine the for the United States in of cocaine as a domestic social of the the to the of our contemporary with Andean cocaine in the that the United States its a global cocaine of and Peru of its Yet what was the most American with cocaine the illicit of the to its through its and our of hemispheric drug ever and are but to with cocaine’s new illicit over a transnational the long of American a drug of to of traditional supply and the high social a for a for was its and a for in of or new drug was to in the as and in American as the new as from and as supply networks more drug with a of legal and public This in the when the drug and of the into cultural and of American foreign drug the were also This the United States became the of a global of the late in on and the beyond the to into its emerged and with more and became the of the international on both of the our an mind-altering to the the of the the of a and drug was by This in the of was still a here. the U.S. in the more on and the United States of popular coca were that its and its the was a of One domestic in became in the this in U.S. cocaine as cultural of cocaine, or its when around as a and the was also the of any cocaine networks that had the the and and and in each U.S. the cocaine and and by the coca itself as a with the of on the Coca to where in the Andes of the including Peru and to the and in our of by the late the world’s cocaine a and United States the of Peruvian drugs to the of and from that on to the North American and Peruvian of the or Peru became a with cocaine and of which into a hemispheric of a on Peru on its cocaine and from national health to of the a Peru in United for its became more and more about cocaine; that in the and and cooperation drugs a first to the United States coca were the where the of legal cocaine their in By the in legal cocaine had the of the market in the was in the new of by U.S. foreign first real the of in the late and into tea and coca had not was as the Peruvian to from the high the this the a large to and new to the and the one already the of the making America’s in a and transnational of cocaine was in Peru. and making the on cocaine an Peruvian of the Coca coca leaf as a international social and was by and medical a Andean scientific about coca on Peru to about to the of a classic to including the of a national a to a of the and and the by of the cocaine this came the of a from to the of of the in on the of American was not U.S. and drug had the Andean the before. the and and of legal were those with more to of cocaine was that in the United but of was from to but such as the was a drugs on the and the U.S. drug and in Peru. had and both the of of cocaine; the events of the of cocaine will not the that U.S. that the was the of cocaine, by definition was the of illicit cocaine, which through a in by make the of the legal tons of a the the to over tons of cocaine on to an and of the networks from coca’s in the for one a global of drug American demand, or drug of a the of cocaine as the menacing drug of the was the of American and policies are some real not long cultural that a illicit cocaine not cocaine public or the foreign drug or political the and cocaine and both in with an transnational of illicit of the and those and as U.S. drug to the the first stage, the of the and more and of illicit the stage, in the U.S. and networks into high of the is with those in including had and in the legal cocaine is of By U.S. cocaine in and working and to which had its indigenous coca in the the Andes as in and the but in from the the traditional legal coca through the illicit cocaine, with of in and of and drug the U.S. drug the such as the in with and By the late cocaine in and as as and in the and By the of more and from the eastern Andes in and By became the of for cocaine and for associated with This of was by the the U.S. and in about cocaine’s illicit public U.S. of for in not in in in in and a in the cocaine from than American supply and the United States three for the the of the on the of the the United States was to American to illicit cocaine, as as to from to working in on which had in and the But by cocaine was also in to its eastern and illicit cocaine into U.S. by domestic to than 1,000 some drug first public as a of the and But were and a on the of Cocaine by the as the of the and drug By to go a to the cocaine U.S. and and the and of the of the cocaine more than a new U.S. in to the and the of a sense of the sense was one of American confidence and the of of this illicit of cocaine in the also in Peru. illicit was born as an of Andean to the degree that official to drug for social came mainly from to not in to the legal coca of the the and the of emerged as the in the as for of and new coca still public over the the in official as the vast in and the of the of into a national and was as a to in the By the late the U.S. had by the most dynamic of to the Peruvian and and the but by the national was the and of of were left to their in of traditional social a dynamic of public also behind the of the as the illicit coca the of the coca as a to a staple when was of By were with of a new of around with roots in coca and an for to them, be with and in the or the with and Peruvian the as Peru into of political and social a crisis of and popular comparable only to the of the had the legal cocaine a century its coca from and is to Peruvian such as drugs as an American and only were to the the in the was to their the for a on the of was as as and on the commodity illicit as a of the legal cocaine of Coca into more by Peru had some and illicit cocaine 1,000 the the cocaine from the of the and to for and with the in shifting cocaine’s current to in the a itself by of and in the of of the of in a of of and to the United and a of working from to had coca and had the most of U.S. the new cocaine market in large in the North and an of of mainly to the imported the and on the drug to cocaine in the the official on was what about with the for for became an of cocaine and thus embraced cocaine as a or the on drug and one a to that the of U.S. drug in cocaine through a By the late the and of illicit cocaine, an to the the of with cocaine from by of that left a of and from to and the were in from to in the of cocaine’s and new U.S. medical the Cocaine by and to the and the and Peruvian and with or of one is became the of the of and to a of cocaine the while social were by the of cocaine from over in drug on the of Andean and of good and drug the the cocaine, the of illicit drugs the and of coca itself to a of U.S. of the was to for drug between and the of cocaine in from to a the in this and cocaine became to the in the U.S. to the and drug became cocaine’s both and U.S. on drugs of the late new and of coca by in the the new Peruvian of itself and on the which coca and cocaine coca and to the Peruvian an and one of the U.S. to into and this has emerged as the drug of the on which a Cocaine a and in the United American has in for while has a of than and on the of our cocaine But U.S. drug as 1910, to of as and as the in the in the Andes the cocaine has an era of of coca leaf the an indigenous of cultural worth as a herb and or still and of this era into our historical and for in global cocaine from to and to what is in of tons the dynamic between the United States and illicit historically in with official growing of and in cocaine the still North American drug by cocaine, still by and and a foreign not one to historical some from this long and history between coca and cocaine, and this long and between the United States and the eastern But a new and on cocaine’s century or more of in cocaine was and first as a modern global commodity as a foreign and as a and illicit drug to the to and to historical of with from drug studies. are in their transnational of cocaine’s and one to current the and on both of a long linking the United States and the Andes of cocaine’s cocaine in transnational overcome drug for as the of the of our or as the of by Andean “drug its social and forces in to and each Second, and the a of cocaine’s history is the of and

Nazmul Chaudhury, Jeffrey S. Hammer, Edmundo Murrugarra

This study examines the impact of a fee-waiver program for basic medical services on health care utilization in Armenia. Due to the reduction in public financing of health services and decentralization and increased privatization of health care provision, private out-of-pocket contributions are increasingly becoming a significant component of health costs in Armenia. To help poor families cope with this constraint, the Government of Armenia provided a free-of-charge basic package service to eligible individuals in vulnerable groups, such as the disabled and children from single parent households. Drawing upon the 1996 and 1998/99 Armenia Integrated Survey of Living Standards (AISLS), which allows the identification of eligible individuals under this program, we estimate the impact of the fee-waiver program on utilization of health services, particularly among the poor. Across the two survey rounds utilization rates have indeed declined despite comparable levels of income, and this decline has occurred among both the poor and the rich, with average utilization falling by 12 percent between the two surveys. However, families with four or more children, the largest beneficiary group under the "Vulnerable Population" program, have decreased their usage of health care services in a disproportionate manner -- 21 percent reduction in usage between the two survey rounds. This precipitous drop in health care usage by this vulnerable group despite being eligible for free medical services, suggests that the program just by itself was inadequate in stemming the decline in the usage of health services. We furthermore present evidence to suggest that the free-of-charge eligibility program is acting more like an income transfer mechanism, particularly to disabled individuals. Contents...

Tim Bell, Harold Thimbleby, Mike Fellows, Ian H. Witten · 6 authors

No abstract is available for this record.

A. Kilkerry Neto, Gerson Zaverucha, Luı́s Alfredo Vidal de Carvalho

Pinkas defined (1991, 1992) a bi-directional mapping between propositional logic formulas and energy functions of symmetric neural networks. He showed that determining whether a propositional logic formula is satisfiable is equivalent to finding whether the global minimum of its associated energy function is equal to zero. He also defined how to transform a first-order resolution-based theorem proof of a formula (query Q) from a given set of formulas (knowledge base KB) into a set of constraints described by a set of propositional logic formulas C. Then he showed that the satisfaction of C is sound and complete with respect to a first-order resolution-based proof of Q from KB. Therefore finding that the global minimum of the energy function associated to C is equal to zero is sound and complete with respect to a first-order resolution-based proof of Q from KB. The proof itself could be extracted from the state of the neurons when the network stops in the global minimum. Pinkas did not implement his system. In this work we point out some adjustments to C and we present an implementation of the revised system. We also show some experimental results and point out some future works.

P.A. Patsouris

We develop a formal multi-agent system based on a modal algebra enabling us to preserve the essential characteristics of its autonomous software agents (autonomy, mobility, etc.), as well as to explore the formal properties and management of the cooperations (non-hierarchical or flat structures) and coordinations (hierarchical structures) among those simple agents, that can be constructed through the operations of the model. We show the potential of these operations that allow us to construct different cooperations and coordinations based on the same set of autonomous agents (as alternative solutions with respect to the same given problem), while, in parallel we provide the means in order to explicitly specify different types of coordinated flows of information specified and governed by these structures. We illustrate all the above via a number of algorithms referring to the development of a simple (in structure) data mining system. We simply selected an adequate application area with no purpose to compare data mining methods and techniques. The various algorithmic solutions we suggest, unveil the resilience of the alternative design approaches aiming at improving issues like decentralization of services, as well as enhancing performance through concurrent organization by thus exploiting the different possibilities of the model.

Cynthia Dwork, Moni Naor, Omer Reingold, Larry Stockmeyer

We prove that three apparently unrelated fundamental problems in distributed computing, cryptography, and complexity theory, are essentially the same problem. These three problems and brief descriptions of them follow. (1) The selective decommitment problem. An adversary is given commitments to a collection of messages, and the adversary can ask for some subset of the commitments to be opened. The question is whether seeing the decommitments to these open plaintexts allows the adversary to learn something unexpected about the plaintexts that are unopened. (2) The power of 3-round weak zero-knowledge arguments. The question is what can be proved in (a possibly weakened form of) zero-knowledge in a 3-round argument. In particular, is there a language outside of BPP that has a 3-round public-coin weak zero-knowledge argument? (3) The Fiat-Shamir methodology. This is a method for converting a 3-round public-coin argument (viewed as an identification scheme) to a 1-round signature scheme. The method requires what we call a "magic function" that the signer applies to the first-round message of the argument to obtain a second-round message (queries from the verifier). An open question here is whether every 3-round public-coin argument for a language outside of BPP has a magic function.It follows easily from definitions that if a 3-round public-coin argument system is zero-knowledge in the standard (fairly strong) sense, then it has no magic function. We define a weakening of zero-knowledge such that zero-knowledge ⇒ no-magic-function still holds. For this weakened form of zero-knowledge, we give a partial converse: informally, if a 3-round public-coin argument system is not weakly zero-knowledge, then some form of magic is possible for this argument system. We obtain our definition of weak zero-knowledge by a sequence of weakenings of the standard definition, forming a hierarchy. Intermediate forms of zero-knowledge in this hierarchy are reasonable ones, and they may be useful in applications. Finally, we relate the selective decommitment problem to public-coin proof systems and arguments at an intermediate level of the hierarchy, and obtain several positive security results for selective decommitment.

Oded Goldreich, Salil Vadhan

We consider the following (promise) problem, denoted ED (for Entropy Difference): The input is a pair of circuits, and YES instances (resp., NO instances) are such pairs in which the first (resp., second) circuit generates a distribution with noticeably higher entropy. On one hand we show that any language having a (honest-verifier) statistical zero-knowledge proof is Karp-reducible to ED. On the other hand, we present a public-coin (honest-verifier) statistical zero-knowledge proof for ED. Thus, we obtain an alternative proof of Okamoto's result by which HVSZK: (i.e., honest-verifier statistical zero knowledge) equals public-coin HVSZK. The new proof is much simpler than the original one. The above also yields a trivial proof that HVSZK: is closed under complementation (since ED easily reduces to its complement). Among the new results obtained is an equivalence of a weak notion of statistical zero knowledge to the standard one.

Atsushi Hayashi, Toshifumi Satake, S. Yokozeki

A flexible and adaptive artificial system must have two different capabilities: the diverse behavior of the system should be dynamically inducible, and the induced unstable behavior should be able to be coordinated into a specified stable state. It can be considered that flexibility is a phenomenon where a system has non-trivial behavior, and adaptability is the ability to find a certain state that is well-fulfilled in a specified situation from within such non-trivial behavior. A decentralized autonomous system framework gives the capability of flexibility for an artificial system by its instability characteristics being within the composition of its framework. On the other hand, adaptability can be derived by self-organization to coordinate the diverse system's behavior towards a certain state. This paper shows a formalism of self-organization in a decentralized autonomous system framework in a company with the feasibility of applying self-organization into a concrete engineering system problem.

Masashi Katsumata, Haruo Hayami

Recently, the autonomous decentralized heterogeneous environment has been realized by integrating CORBA and Internet technology. On the other hand, workflow management systems have been introduced into organizations. However, it is difficult to apply workflow management system to coordinate workflow across the multiple organization. The next step of introducing workflow in organizations requires technology to link the workflow across multiple organizations. We call this interworkflow. We propose interworkflow for the autonomous decentralized heterogeneous environment and discuss its functional model.

Arun Sahai

We introduce the notion of non-malleable non-interactive zero-knowledge (NIZK) proof systems. We show how to transform any ordinary NIZK proof system into one that has strong non-malleability properties. We then show that the elegant encryption scheme of Naor and Yung (1990) can be made secure against the strongest form of chosen-ciphertext attack by using a non-malleable NIZK proof instead of a standard NIZK proof. Our encryption scheme is simple to describe and works in the standard cryptographic model under, general assumptions. The encryption scheme can be realized assuming the existence of trapdoor permutations.

Debbie W. Leung

Quantum process tomography is a procedure by which an unknown quantum operation can be fully experimentally characterized. We reinterpret Choi’s proof [Linear Algebr. Appl. 10, 285 (1975)] of the fact that any completely positive linear map has a Kraus representation as a method for quantum process tomography. The analysis for obtaining the Kraus operators is extremely simple. We discuss the systems in which this tomography method is particularly suitable.

Christine R. Martell

Very few researchers have addressed the long‐term financing arrangements of municipal governments in developing countries. No research has evaluated empirically either the elements that affect municipal borrowing in developing countries or what those elements reveal about the municipal credit system. Analyzing Brazilian municipal loan and financial data with a series of simultaneous equations, this paper addresses the following questions: What factors determine municipal government investment levels, borrowing levels, and borrowing prices? What do empirical data reveal about the character of the Brazilian municipal credit system? The results show that investment, borrowing, and borrowing prices are interconnected. Furthermore, while some signs of a market‐based system exist, there is evidence that investment and borrowing decisions are made within an administered market.

Ahmet Akyol, Kartik Athreya

Tertiary education in the U.S. requires large investments that are risky, lumpy, and well-timed. Tertiary education is also heavily subsidized. By making the risk of human capital investment more acceptable, especially to low wealth households, subsidies may increase investment in human capital, lower long-run inequality, and reduce aggregate precautionary savings. However, subsidies also encourage more poorly prepared students to attend and are usually financed via distortionary taxes. In this paper, we find that observed collegiate subsidies improve welfare substantially relative to the fully decentralized (zero subsidy) outcome. We show that subsidies help smooth consumption, lower skill premia, increase interest rates as precautionary savings fall, lower the inequality of both consumption and wealth, increase intergenerational income mobility and raise welfare, even when financed by distortionary taxes.

Juliano de Carvalho Lima

This work analyzed the management system in a health district in the state of Rio Grande do Sul through qualitative analysis, utilizing a case study as methodology and the Macro-organization Theory (Matus, 1996) as its analytical framework. The objectives were a) to identify the processes of establishing and implementing both the mission statement and its objectives towards the management of public health in the region; b) to analyze how the health coordinators manage their time and how they select which issues deserve the most attention; c) to analyze the steps, procedures and metrics in regards to how the application and accountability processes at the Unified Health System in the region function; d) and to analyze how the competencies within the regional health system are allocated. The results indicated that the established Analytical Model, composed by categories such as a) Directionality/ Compliance system applied to manager’s agenda b) Responsibility / Requisition and Accountability Systems; and c) Decentralization and Autonomy/ Management System by Operations was well suited to evaluate the health management system. The management system currently in place at the 6th Health Region has in its clear mission statement and in its wide acceptance by health workers an enhancement factor towards the current organizational practices within the health system. Nevertheless, the way health coordinators are currently prioritizing their time has diverted necessary resources from critical problems towards more remedial issues. The 6th Health Region has strengthened social responsibility in order to improve accountability in the region. Quality assurance management, though, presented room for improvement for there were no established goals, objectives and accountability. The decentralized consulting applied to the municipalities and the financing model have both promoted decentralization and autonomy, although this strategy demands a better regional integration and more engaging managerial practices.

Eduardo Chaves, Julio Salazar

Elections around the world have become a major international concern since the inception of modern democracy. It is a fact that the success of any democracy depends largely on its electoral process. In conducting a free and credible election, the process must be transparent to be adjudged credible. The electioneering process begins with the compilation of a voter register; this register contains the details of every eligible voter as stipulated by law or guild lines that guilds the electoral process. As part of what makes up, the guidelines are age restrictions for every intended voter. It is forbidding by law in most countries for a child to register as a voter, but this is not so in reality in most countries, especially in a developing nation. Because the age restriction is not obeyed, this has resulted in the incidences of underage voters and disputed election outcomes. This work provides an efficient and effective solution for the above concerns, using multiple digital solutions. The model will be integrating a deep learning Convolutional Neural Network (CNN), an Interplanetary File System (IPFS), and an Ethereum Smart Contract Blockchain. The role of the CNN is to detect any underage individual who intends to register as a voter. The CNN is built with a pretrained dataset, and it was trained with an age classifier that grouped the age on the images on the data set into eight distinct groups. This age grouping will help the age predictive algorithm estimate and place every image on the camera in a unique age group. This will only produce a binary result, which is "eligible to voter or not eligible to vote." This outcome is based on the preset threshold cut-off on the age group. The Interplanetary File System (IPFS) will provide a large storage capacity that will allow for off-chain data storage and still provide the model with all the functionalities and benefits of the blockchain. It also provides a hashing function that will assign and identify every registered voter with a unique cryptographic Identity. This ID will prevent the storage of the same information into the database, in so doing, eliminating multiple voting. Finally, the blockchain will provide a voting platform where the model will be implemented. It will allow every registered voter with a unique ID to create an account and vote on the blockchain. The adapted CNN was tested and evaluated and shows 85.9% performance accuracy, and when compared against two other age predictive models, it recorded an increase of 1.2%. In comparison, the complete digital solution model recorded 95.3% in performance. We believe this model will perform even better when subjected to further research work.

Fu Li

It has more than four years that a centralized monetary policy and a decentralized fiscal policy were practiced within Euro-area. Practice has proved that there is little harmonious between monetary policy and fiscal policy, and there really exist some shortcomings in the set of institutes and design of policies' structure in European Currency Union. It is in a dilemma to carry out expansive monetary policy for the main object of alleviating inner impact and stabilizing price. It is one of the measures to improve harmonious of monetary policy and fiscal policy that realize a centralized big finance, redistribute resource through finance transferring in order to help members of the Union reducing the effect of asymmetric impact.

YU Qing-wei

s:ABS is the financial innovation tool which has been developed rapidly in the field of the international finance in recent 30 years. ABS can improve mobility of assets of commercial banks, decentralize the risk, and improve the security of the assets and the management of assets-liabilities. ABS is also beneficial to the development and perfection of our country's capital market and raise the capital sufficient rate of the commercial bank.

Authors unavailable

The editors of SIAM Review are delighted to present a SIGEST paper about cryptography, a topic that appears frequently these days in mainstream news media. Stories about computer security, defenses against terrorism, privacy, and file swapping invariably refer to cryptographic systems, which thus represent an extraordinarily visible example of the practical application of mathematics and computer science. Encryption systems depend on a stream of new mathematical results and algorithms; it may take years of study by experts to prove that a proposed technique is secure (or not). An additional wrinkle is that humans tend to avoid any encryption procedure that they perceive to be too much trouble, which means that researchers in cryptography need to consider criteria like ease of use as well as more precise properties. Cryptographers are blessed with, and continue to devise, engaging terminology and even some implied personalities. No discussion of cryptography is complete without Alice and Bob---so much more appealing than A and B---whose roles may, however, vary. For example, Alice and Bob are sometimes friends eager to communicate secrets without others learning them, and sometimes two people who need to communicate but do not know or trust each other; new variations on Alice, Bob, and their relationship are constantly emerging. Another fixture in cryptography is the presumably evil adversary, who may be passive (an eavesdropper limited to observing the information traffic sent between Alice and Bob) or active (someone who can see and modify the traffic). Wide use is made of "zero knowledge proof systems" (an apparently contradictory term), and this paper defines an evocatively named "garbage/not garbage" oracle that is useful in validity checks. The standard requirement of semantic security for cryptosystems means that an adversary learns nothing about the original text (the "plaintext") from its encrypted form (the "ciphertext"). The stricter requirement of nonmalleability, needed to hide information from active adversaries, means, roughly speaking, that an adversary cannot use the ciphertext associated with an original plaintext to produce an encryption of a related plaintext. This issue's SIGEST paper, "Nonmalleable Cryptography," by D. Dolev, C. Dwork, and M. Naor, which first appeared in 2000 in volume 30 of the SIAM Journal on Computing, identified and addressed the concept of nonmalleability. The paper has been extremely influential, is widely cited, and has inspired a substantial level of related research. For the paper's appearance in SIGEST, the authors have added an extended and completely new preface, intended for the general SIREV reader, that introduces much of the terminology, presents easily understood examples, and brings the reader up-to-date on related problems. Section 1.4, on deniable authentication, clarifies some of the many complications in defining new protocols and their desired (or undesired) security features. The original paper itself explores in detail the implications of nonmalleability, presenting nonmalleable schemes for three key problem classes and proving security against strong ciphertext attacks. We are grateful indeed to the authors for their extra efforts to make this important paper accessible to nonexperts in cryptography.

S. Armeni, D. Christodulakis, Ioannis Kostopoulos, Yannis C. Stamatiou · 5 authors

In this work, a method for proving copyright ownership is presented that is based on Zero Knowledge Interactive Proof (ZKIP) protocols for computationally intractable problems. The utilized problem is the 3-coloring problem, which consists in assigning one of three available colors to the vertices of a graph so that no two adjacent vertices have the same color. Using the presumed computational intractability of this problem, the construction of large signatures is proposed so that they represent adjacency matrices of random, 3-colorable graphs. Since it is easy to construct large graphs with a prescribed 3-coloring of their vertices whereas it is difficult to discover such a 3-coloring, the owner of a copyrighted digital piece of work (e.g. image, audio, video) may easily generate a random 3-colorable graph, embed it in the digital object and then use the knowledge of the 3-coloring in debates over the object’s ownership. Due to the intractability of the 3-coloring problem, only the owner is able to produce it sufficiently fast in an ownership challenge so as to convince a third party that the graph was indeed embedded in the object by herself/himself. Since graphs with maximum possible resistance to well-known coloring algorithms is required, we exploit some relatively recent experimental and theoretical findings suggesting that hard 3-coloring instances are found among graphs having a vertices to edges ratio around a specific threshold value. The proposed scheme has the additional advantage that disclosing the signature is of no consequences since it is essentially the knowledge of a characteristic of the signature, i.e. the 3-coloring of the graph it represents, that enables one to use it as proof of ownership of some digital object that contains it. Even if someone managed to locate and extract the signature, to use it would require a fast solution to a computationally intractable problem on some hard instance. Our proposal represents a shift from signatures that are simply viewed as bit sequences to signatures with properties that stem from their interpretation as instances of computationally intractable problems.