Blockchain Papers

Donald Beaver

No abstract is available for this record.

Liqun Chen

No abstract is available for this record.

H A ElZein, Maureen Birmingham, Z. A. Karrar, A A Elhassan · 5 authors

In 1993 a large outbreak of paralytic poliomyelitis occurred in Sudan as a result of an accumulation of large numbers of susceptible children that was accelerated by faltering immunization services. The extent of the outbreak led to the rapid rehabilitation of Sudan's Expanded Programme on Immunization (EPI); the government began financing vaccine purchase, operational aspects of EPI were decentralized, vaccine delivery was changed from a mobile to a fixed-site strategy, a solar cold chain network was installed, inservice training was resuscitated, and social mobilization was enhanced. National immunization days (NIDs) for poliomyelitis eradication were conducted throughout the country, including the southern states during a cease fire in areas of conflict. Measles immunization coverage was increased by offering measles vaccine during the second round of NIDs and subsequently through routine immunization services. Supplemental tetanus toxoid immunization of women of child-bearing age began in three provinces at high risk for neonatal tetanus. From 1994 to 1996 reported immunization coverage increased and the incidence of all EPI target diseases fell. Trends in coverage, disease incidence, financing, and the implementation of WHO-recommended disease-control strategies suggest that more sustainable immunization services have been re-established in Sudan.

政三 大川

No abstract is available for this record.

A. T. GREEN, Klaus Jochem

National leprosy control programmes currently face a number of changes to the environment within which they operate. This paper examines the issues arising from these. It focuses, in particular, on those arising from changes in the structure of the health sector as a result of policies of health sector reform which are being considered or adopted in many developing countries. These include decentralization, financing strategies, greater role for the private and NGO sectors and the integration of vertical programmes. The paper is structured around a number of key steps in the development of a strategy for sustainability of appropriate leprosy services. These are the assessment of the epidemiological, social and health services context, development of programme objectives, planning of human and financial resources, development of the strategy, mapping the roles of potential actors, development of regulatory and incentive mechanism, action planning and managing change and, finally, re-evaluation of the programme objectives and service delivery organization. The paper stresses the importance of process in developing ownership of a strategy. It concludes with a set of key questions which it suggests need to be addressed by leprosy programme managers in the development of a proactive response to the changes.

Guillaume Poupard, Jacques Stern

No abstract is available for this record.

Wallace E. Huffman, Richard E. Just, Huffman, Wallace E., Just, Richard E.

This paper reviews agricultural research structural and organizational changes in western developed countries, examines new financing prospects for agricultural research, and provides some tentative conclusions about which organizations are best positioned to provide services for the twenty-first century. Given that these countries face many similar economic, political, scientific, and agroclimatic factors and fiscal issues, we can expect a set of similar new developments that have potentially important and widespread long-run implications. After three common developments are outlined, principles of impure public good financing are applied leading to the following agricultural science policy recommendations: (i) new political jurisdictions should be formed to finance research, e.g. new alliances across countries and subregions within large countries; (ii) intellectual property rights should be strengthened to increase the total amount and share of total (public and private) agricultural research that is privately financed and conducted, i.e. the private sector should find it profitable to undertake a large share of applied research but not be expected to finance public-sector agricultural research; and (iii) the public sector should redirect its research efforts increasingly to areas that are socially worthwhile, but not privately undertaken, e.g. in the basic and pretechnology areas, on environmental, resources, food safety and human nutrition, and policy. Finally, large countries that have developed a system of shared public and private financing and performance and decentralized public support of agricultural research seem best positioned for meeting the needs of the twenty-first century.© 1999 Elsevier Science B.V. All rights reserved.

Frank Dignum, G.J.P.M. Houben

This paper describes a new approach to design modern information systems that offer an integrated access to the data and knowledge that is available in local applications. By integrating the local data management activities into one transparent information distribution process, modern organizations can offer better support for its workers in the execution and coordination of their work activities. Observing practical applications of decentralized, autonomous and heterogeneous information systems we see deficiencies in currently available approaches to model such information systems. They do not acknowledge the pivotal role that (informal) communicating workers play in the context of an entire organization. The interaction between the members of social and informal groups of employees makes it possible that (in many of today’s information-intensive enterprises) the local structured procedures can be effectively and flexibly integrated into global work processes supporting the business goals. Traditional design techniques concentrate on either the structured local procedures (and its local database applications), the structured global process (and its global business goals), or the informal (less structured) communication between individuals. We suggest to combine an activity-based model (suited to describe the structured parts of the processes) with a goal- or conversation-based model to tie the different elements together. Using an agent architecture we show that it is possible to implement this integrated approach. The different types of cooperating agents support the individual workers by assessing the goal of the activity, the applicability of the standard procedure, and the availability of alternative knowledge and information in order to supply the necessary information.

Daniel Verdier

The internationalization of capital markets that occurred during the era of the classical gold standard (1870-1914) was part of a broader set of trends that threatened to drain local markets from capital and channel that capital to the national financial center and, from there, toward other national financial centers. Still, internationalization was neither inevitable, uniform, nor irreversible but was a political choice informed by redistributional considerations between rival domestic interests and decided by politically dominant coalitions. The domestic institutional structure in each country determined the composition of the politically dominant coalition. Decentralized structures allowed potential losers to curb public policies favorable to capital market internationalization, whereas centralized structures allowed expected winners to promote such policies. As a result, economies with centralized states ended up being the most dependent on the international capital market, whereas economies with decentralized states took a less active part in the globalization of finance.

Oded Goldreich, Amit Sahai, Salil Vadhan

We show how to transform any interactive proof system which is statistical zero-knowledge with respect to the honest-verifier, into a proof systemwhich is statistical zero-knowledgewith respect to any verifier. This is done by limiting the behavior of potentially cheating verifiers, without using computational assumptions or even referring to the complexity of such verifier strategies. (Previous transformations have either relied on computational assumptions or were applicable only to constant-round public-coin proof systems.) Our transformation also applies to public-coin (aka Arthur-Merlin) computational zero-knowledge proofs: We transform any ArthurMerlin proof system which is computational zero-knowledge with respect to the honest-verifier, into an Arthur-Merlin proof system which is computational zero-knowledge with respect to any probabilistic polynomial-time verifier. A crucial ingredient in our analysis is a new lemma regarding 2-universal hashing functions. 1 Introduction Zer...

J. Lawrence Broz

This article explains (1) the origins of central banking and (2) variations in the spread and durability of central banks across nations. Early central banks helped bind governments to honor their debts and thereby furthered governments' capacities to efficiently finance military expenditures. The origins of central banking are problematic because government credit-worthiness and efficient wartime fiscal policy are public goods, subject to the free-rider problem. Applying a variant of the joint-products model, I argue that governments offered private benefits (monopoly privileges) to select creditors to induce participation in central banks. To explain cross-national differences, I argue that the level of domestic political decentralization negatively affected the incidence and durability of central banking. Countries with decentralized political systems faced regulatory competition from strong local authorities as licensers of banking monopolies, making it difficult to adopt or sustain central banking. Qualitative and statistical evidence from Europe and the United States to about 1850 support the arguments.

Cynthia Dwork, Moni Naor, Amit Sahai

Concurrent executions of a zero-knowledge protocol by a single prover (with one or more verifiers) may leak information and may not be zero-knowledge in toto . In this article, we study the problem of maintaining zero-knowledge.We introduce the notion of an (α, β) timing constraint : for any two processors P 1 and P 2 , if P 1 measures α elapsed time on its local clock and P 2 measures β elapsed time on its local clock, and P 2 starts after P 1 does, then P 2 will finish after P 1 does. We show that if the adversary is constrained by an (α, β) assumption then there exist four-round almost concurrent zero-knowledge interactive proofs and perfect concurrent zero-knowledge arguments for every language in NP . We also address the more specific problem of Deniable Authentication , for which we propose several particularly efficient solutions. Deniable Authentication is of independent interest, even in the sequential case; our concurrent solutions yield sequential solutions without recourse to timing , that is, in the standard model.

Joe Kilian, Erez Petrank

No abstract is available for this record.

Pranab Bardhan, Dilip Mookherjee, Bardhan, Pranab, Mookherjee, Dilip

This two-part paper provides a theoretical framework for appraising trade-offs between alternative methods of delegating authority over the delivery of public services, on the targeting and cost-effectiveness of public spending programs in developing countries. Authority over these programs has to be delegated owing to absence of information at the central level concerning local needs and costs of specific communities. In a top-down centralized system, this authority is delegated to bureaucrats by a central government that has limited ability to monitor their performance with respect to either service delivery or cost control. In a decentralized system, it is allocated instead to elected local governments or client groups, which may be subject to capture by local elites. Both systems are thus prone to local corruption and lack of accountability. Part 1 of the paper studies the relevant tradeoffs in the context of a poverty alleviation program, whose aim is to deliver a private merit good available on competitive markets to the poor. Decentralization generally dominates with respect to inter-community targeting as well as cost-effectiveness. However, the ranking of intracommunity targeting under the two systems is ambiguous, and depends on the relative degree of capture that local and national governments are prone to, besides the nature of uncertainty and preferences of the good by the nonpoor. Part 2 of the paper considers an infrastructure service provided by a public enterprise which has a natural monopoly. In this context it is shown that decentralization dominates if the following four conditions are satisfied: (i) local governments are not vulnerable to capture; (ii) local governments have access to adequate local financing sources; (iii) there are no interjurisdictional externalities in service provision; and (iv) local governments have all the bargaining power and access to relevant cost information vis-a-vis public enterprise managers. Absent any one of these institutional conditions, however, decentralization may perform worse than centralization. The Appendix develops a model of electoral competition (adapted from Grossman-Helpman (1996)) where parties are prone to capture by special interest groups, which helps identify some of the institutional determinants of the degree of capture of local and central governments.

Donald Beaver, Joan Feigenbaum, Joe Kilian, Phillip Rogaway

No abstract is available for this record.

Toshiya Itoh, Yuji Ohta, Hiroki Shizuya

No abstract is available for this record.

Nick Szabo

Smart contracts combine protocols with user interfaces to formalize and secure relationships over computer networks. Objectives and principles for the design of these systems are derived from legal principles, economic theory, and theories of reliable and secure protocols. Similarities and differences between smart contracts and traditional business procedures based on written contracts, controls, and static forms are discussed. By using cryptographic and other security mechanisms, we can secure many algorithmically specifiable relationships from breach by principals, and from eavesdropping or malicious interference by third parties, up to considerations of time, user interface, and completeness of the algorithmic specification. This article discusses protocols with application in important contracting areas, including credit, content rights management, payment systems, and contracts with bearer.

Claus Akira Matsushigue

Various types of sysfems o/ proai/istc proa/s have played a decisive role in the development of Computer Science Theory in the last decade. This can be verified through the great number of studies about interactive proofs, zero-knowledge proofs, and transparent (or holographic) proofs. These topics are guided by the robustness of the codifications and by the computational capacity of checking them. In this text, we aim at presenting a ecncal ntroduc on reZaiue fo the proabilstcaZZy checkaZe robust proa/s. Within this approach. the new characterization of the non-deterministic polynomial-time class through the Probabilistically Checkable Proofs class formulated by Arara, Lund, Motwani. Sudan e Szegedy in IALM+92], ./V'P = PCP(logo, 1), is of central importance. We intend to prove this characterization, because it encompasses the principal points of the subject and. furthermore, covers subjacently a wide set of computational, algebraic. and probabilistic tools. which are fundamental in this topic.

Ivan Damgård, Birgit Pfitzmann

<p>We study the behavior of interactive arguments under sequential iteration, in particular how this affects the error probability. This problem turns out to be more complex than one might expect from the fact that for interactive proofs, the error trivially decreases exponentially in the number of iterations.<br />In particular, we study the typical efficient case where the iterated protocol is based on a single instance of a computational problem. This is not a special case of independent<br />iterations of an entire protocol, and real exponential decrease of the error cannot be expected, but nevertheless, for practical applications, one needs concrete relations<br />between the complexity and error probability of the underlying problem and that of the iterated protocol. We show how this problem can be formalized and solved using the<br />theory of proofs of knowledge.<br /> We also prove that in the non-uniform model of complexity the error probability<br />of independent iterations of an argument does indeed decrease exponentially - to our knowledge this is the first result about a strictly exponentially small error probability in a computational cryptographic security property. <br />As an illustration of our first result, we present a very efficient zero-knowledge argument<br />for circuit satisfiability, and thus for any NP problem, based on any collision-intractable hash function. Our theory applies to show the soundness of this protocol. Using an efficient hash function such as SHA-1, the protocol can handle about 20000 binary gates per second at an error level of 2^−50.</p><p>Keywords -- Interactive proofs, arguments, proofs of knowledge, computational security,<br />efficient general primitives, multi-bit commitment, statistical zero-knowledge.</p>

Helen Roberts

The Family Division of the High Court exercises jurisdiction in family proceedings in England and Wales. A broadly similar jurisdiction is exercised under the Children Act in care proceedings and in private law disputes between parents by county courts and family proceedings courts. It should be emphasised that this article is about civil, not criminal, proceedings in which the burden of proof is diVerent and the practice which I describe does not apply. 2 The most recent example is the acknowledgment by the Court of Appeal that paediatricians and child psychiatrists are entitled in family proceedings to express opinions on child abuse which are based on or take into account the expert's assessment of the child's truthfulness: see Re M and R (Child Abuse: Evidence) [1996] 2 FLR 195, CA. Equally, I do not have space to address the duties of experts generally, as to which there is agreement across all the divisions of the High Court that expert evidence presented to the court should be and should be seen to be the independent product of the expert uninfluenced as to form or content by the exigencies of litigation. In Re J [1991] FCR 191 at 226/7, Cazalet J said that in children's cases the duty to be objective and not to mislead is as vital as in any case, because the child's welfare is at stake, and his/her interests are paramount. He added that an absence of objectivity may result in a child being wrongly placed and thereby unnecessarily at risk. It must also be borne in mind that a misleading opinion from an expert may well inhibit a proper assessment of a particular case by the non-medical professional advisers and may also lead parties, and in particular parents, to false views and hopes. 3 By section 12 of the Administration of Justice Act 1960, as amended by Schedule 13, para 14 of the Children Act 1989, it is a contempt of court to publish information relating to proceedings brought (inter alia) under the Children Act. 4 Oxfordshire County Council v M [1994] Fam 151, CA: Re L (A Minor) (Police Investigation) [1996] 2 WLR 395, HL. 5 By section 1(2) the court is required to have regard to the general principle that any delay in determining questions relating to the upbringing of children is likely to prejudice their welfare. 6

E. Gauthier, J.-Y. Le Boudec, Philippe Oechslin

We present a protocol for controlling a shared ATM multicast tree supporting many-to-many communication. The protocol supports one or several ATM virtual channel connections (VCCs) of the many-to-many type. The number of VCCs is independent of the number of endpoints. The protocol guarantees that there is no interleaving on any VCC of the tree. The protocol also guarantees that the traffic contract associated with the VCCs is respected, thus making it possible to use ordinary VCCs of the constant bit rate (CBR), variable bit rate (VBR), or unspecified bit rate (UBR) class. No resequencing server or cell buffering inside the network is required, and all cell forwarding is performed at the ATM layer. We describe the protocol both informally and formally.

グレゴリー D. グレイ, Gregory D. Gray

In 1984, slightly more than a decade ago, neo-liberal economic theory under the guise of 'free market' reform was ushered into New Zealand for the first time in the country's history by the ruling Labor Government. The initiation of monetary reform policies sent shock waves throughout the nation. The ensuing fiscal reforms changed the operating patterns of both public and private organizations as well as the lives of individual citizens. This paper examines the political and economic environment which preceded the enactment of the broad sweeping educational reforms. The purpose of this paper is to review policy papers and government documents that affected educational reform and restructuring of the tertiary educational system. Although primarily focusing on tertiary educational change, this thesis will also summarize educational policy changes that premeated compulsory education. As a primary service organization of the state, education was caught up in the tide of market reforms ushered in by the Treasury Department. The initiation of monetary policy changes sent shock waves throughout the nation as it drastically altered the 'cradle to grave' welfare philosophy. Restructuring the educational bureaucracy and establishing greater accountability were the general aim of the decentralization process. The 1989 Education Act stream-lined the educational bureaucracy by dismantling the Department of Education and its ten regional offices. In its place, the Ministry of Education was established with the main function as a policy advisor to the government. This structural change coincided with the tertiary education functions being transferred to four new agencies: 1). The Ministry of Education, 2). The New Zealand Qualifications Authority, 3). The Educational and Training Support Agency, 4). The Careers Service. Tertiary Education in New Zealand was modified in greater detail following the passage of the Education Act of 1990. This act extended the changes initiated with the Education Act of 1989. It essentially established tertiary educational institutions as autonomous bodies and placed polytechnics on the same bureaucratic structure as universities. More importantly, this new educational law of 1990 transferred the technical and skilled training standards to the Ministry of Education. The free market economic reforms initiated in the mid-80's have influenced educational restructuring by expecting more accountability on the part of the educational institution and greater choice on the part of the student consumer. Recent tertiary education reforms highlight the delicate balance between professional and technical education and the needs of the state as well as the rights of the students.

James M. Boughton

The World Economic Outlook (WEO) exercise at the IMF evolved during the 1980s, partly in response to demands by policymakers in national finance ministries for objective and internationally comparable projections and policy scenarios. The exercise had begun as a staff initiative, encouraged by the Managing Director (Johannes Witteveen). Gradually, the Executive Board, the Interim Committee, the Group of Seven, and others came to view the discussion of the WEO documents as an important element in their efforts to keep abreast of world economic developments and prospects. Direct and indirect feedback from those discussions informed the staff as to how the exercise should be improved. Driven by this policy relevance, the WEO evolved from a decentralized project that was only haphazardly model-based into a more rigorous and coordinated exercise.

Ehtisham Ahmad

Financing Decentralized Expenditures presents new original research papers on the structure of intergovernmental fiscal relations in virtually all types of countries and the design and implementation of transfer mechanisms between different levels of government.