Blockchain Papers

S. Dupont, M.J. Crochet

No abstract is available for this record.

M.D. Chilcott, J.M. Rallison

No abstract is available for this record.

J.M. Rallison, E.J. Hinch

No abstract is available for this record.

W.R. Schowalter

No abstract is available for this record.

G.G. Lipscomb, M.M. Denn, D.U. Hur, D.V. Boger

No abstract is available for this record.

REID G. SMITH

No abstract is available for this record.

Peter Lusztig, Bernhard Schwab

No abstract is available for this record.

Alfred K. Neumann, Wen‐Pin Chang

Due to its success, China's family planning programme has attracted attention from other countries seeking to replicate its strategies. Much is known about the organization and operation of China's family planning education and service delivery programmes, yet relatively little is known about costs and programme-financing methods. The authors present information about China's family planning pro gramme from a family and county level administrator perspective, drawing extensively on unpublished recent information to provide insights into costs and methods of financing. A case history illustrates various family planning options available as well as the payment mechanisms for programme incentives. Financial responsibility for the vast majority of the national family planning effort belongs to work units such as factories, educational organizations, stores and cooperatives. Translating the cost of family planning into US dollars and comparing with comparable costs in other developing countries and translating into terms relative to average unskilled Chinese worker salaries reveals the substantial investment made per capita on behalf of the family planning programme. Factors of political will, comprehensive administra tive support, effective organization, an all encompassing motivational programme and extensive service delivery covering the entire country together with generous decentralized financing are presented as important to programme success. Implications for transfer to other countries and the associated costs of doing so are discussed.

James Gleick

LOOKING FOR GOD'S FOOTPRINTS / James Gleick "Have you ever thought, Angelica," said Persse, "what a remarkable thing it is that the moon and the sun look to our eyes approximately the same size? . . . The odds against it happening by chance must be billions to one." "You don't think it was by chance?" "I think it's one of the great proofs of a divine creator," said Persse. "I think He had an eye for symmetry." —David Lodge, "Small World" SURE, IT'S EASY TO make fun. Our planet flies through space more smoothly than any airplane, covered with water yet never spilling a drop, so it must have had a Designer. Our eyes display too complex an architecture to be reached by random mutations, so they must have had a Biological Engineer. Our atmosphere contains just enough oxygen, just enough carbon to support life, so it must have had an Environmental Consultant. New York City offers a brilliantly conceived breeding ground for cockroaches; surely, therefore, we can deduce the existence of a cockroach deity. The so-called argument from design—from design, that is, to the existence of God—had barely been thought up before it was being satirized, and you can't always tell the serious versions from the parodies. But lately science has been upping the ante. No one cares any more that the moon is unusually large (although some have argued seriously that its tidal washing and splashing may have been a precondition for life's forward march out of the primordial oceans). Nowadays we have the incredibly well-tuned gravitational force, which, if put ever-so-slightly out of whack, would have turned the universe into a collection of red dwarf stars or blue giant stars, either way presumably inhospitable. We have the strong force in the atomic nucleus—a little stronger or a litter weaker, and stars apparently could not burn at all. The post-Big Bang expansion seems especially problematic. Nonscientists don't realize how lucky they are that the universe got bigger than a Ping Pong ball. When modern physicists and mathematicians calculate the odds against life as we know it, they no longer speak of "billions to one." They toss around numbers like IO40, or IO3"1, or ten to the ten to the thirtieth, a number that cannot even be typeset without either two levels of superscript or a universe full of zeroes. The Missouri Review · Il Certainly, for most of the last millennium, science and faith have been mortal enemies. Science explains; faith builds on the inexplicable. Certainly, amid the agnostic throng, few modern scientists talk openly about belief in God. Yet even so, as science staggers toward its Grand Unified Theory and other grails, some of its practitioners have been seeing an argument for God's existence in the esoterica of high-energy physics. They feel that somewhere in these cosmological coincidences, and also perhaps in the accumulating perfection of modern mathematics, lies the evidence of design that cannot be explained away. Perhaps, they feel, science is finally reaching a level of knowledge that will confirm God, instead of rendering Him superfluous. This is the argument that got its most vigorous and many-sided airing in John Updike's 1986 novel, Roger's Version. Though never quite so earnest, never quite so garrulous about it, some practicing scientists really do share at least a part of the feeling of Updike's pallid, pimpled antagonist, a computer scientist named Dale Köhler, that, as he says: "The most miraculous thing is happening. The physicists are getting down to the nitty-gritty, they've really just about pared things down to the ultimate details, and the last thing they ever expected to happen is happening. God is showing through." Updike's version contains its share of parody, to be sure. It also assembles the richest hodge-podge of scientific shoptalk to be found anywhere in fiction—absolutely authentic in its slangy allusions to cellular automata and fractal patterns and the Mandelbrot set. Dale Köhler knows his science, and he cannot be laughed at when he says, "They've been scraping away at physical reality all these centuries, and...

A Horwitz

World Bank publications have a large influence on the decisions of governments. This article analyzes the publication "Financing Health Services in Developing Countries: An Agenda for Reform" part of the World Bank Policy Studies series. This study assesses only peripheral reasons for the lack of public and private financial investments in health services. It does not include the result of economic recession, budget cutbacks, and poverty on financing systems. There has been excessive expenditure on luxury in health institutions which takes considerable finances from disease prevention and health promotion services. There is low demand for private services because of the high cost, but public health services sometimes lack tools and money necessary for adequate care. The study does not address the relationship between needs and demand and the supply of health services. It outlines "4 Policy Reforms" in which the aims are to increase to cost of curative services and to use the additional money for prevention. The World Bank favors using private sector services but does not seem to view decentralization of health care as important. Social security systems have been in place in Latin America for 63 years. These systems are funded by wage earners and do not cover lower income rural citizens. Chile was the 1st country to adopt compulsory insurance in 1924 for catastrophes and diseases. The Chilean National Health Service combines institutional and community resources to provide quality health care. Social insurance and other prepayment systems are the rational approaches for financing health care in the Americas. These systems should be based on contributions by the State, employers, and urban and rural workers. There is a need for fund redistribution from institutional curative care to community preventative care. Health care costs should reflect income proportionally. The World Bank contributes vital analysis to the problem of health service financing. Hopefully American governments will recognize the need for health care reform.

Raffel Nk, Raffel Mw

Medical care in Hungary has made significant progress since World War II in spite of other social priorities which have limited financial support of the health system. A shortage of hard currency in a high technological era is now having a particularly severe adverse impact on further development. Decentralized administration and local finance have, however, provided some room for progress. Preventive efforts are hampered by a deeply entrenched life style which is not conducive to improving the population's health status.

Alain Fonteneau, Alain Gubian, Henri Sterdyniak, Christine Verpeaux

What Prospects for French Social Security ? A. Fonteneau, A. Gubian, H. Sterdyniak, C. Verpeaux In the future, the ageing of the population, increases in health expenditures, the rise of unemployment and the necessity to encourage the birth rate will make the problems of the social security more acute. Is it possible to finance spreading social transfers without undermining economic growth ? Could one reform the social welfare system to avoid the extension of transfers ? To get clearer social choices and to aim at macroeconomic balance, social benefits should be financed only by households. Workers would contribute to the insurance role of social security ; income tax would provide for solidarity. Shifting all contributions on to wage earners and raising wages accordingly would have no short-term impact. However, employers would be assured that gross costs were not to be increased and indeed would remain stable. Replacing employers' contributions by a turnover tax or by VAT would not result in better economic performance. Substituting part of the employers' contributions by a tax on machines would stimulate the saving of capital and employment. A solution of liberal obedience that would separate solidarity financed by the Government from privately financed individual insurance seems neither viable nor desirable. As far as health expenditures are concerned, the development of private insurances would deny the principle of equality of all men in respect of medical care. Insurance companies would be tempted to make a select among their potential clients and to exclude those who present too many risks. Two other ways seem to be more promising, even though they include risks. In the first case a centralized control of the care supply is based on an assessment system of medical techniques. In the second one, coordinated networks of care are based on decentralization.

M. Owen

Italy now ranks 8th in the list of countries worst hit by AIDS. The relatively low figures for homosexual AIDS cases give no cause for complacency. It is not known yet if the message about 'safe sex' has got across to homosexuals, or if there has been underreporting and the numbers with AIDS will start soon to show the same rising curve as that for drug users. The Vatican, as was always expected, has said 'no' to the use of condoms to combat the spread of HIV, even though its use would not be to avoid conception but to prevent disease. Many doctors working in the field resent the lack of consultation and communication between Rome and the regions. But Italian health services are decentralized; the 21 regional health authorities are autonomous bodies. They have never looked to central government for specific directions, but they do desperately need extra funding. Their literature has been important as means of countering 'disinformation' from the press, often prone to sensationalism. Discrimination against children of parents infected with HIV has occured in schools and frequently seropositive employees have been fired. Local authorities are now making great efforts to impart the correct information. The Italian family planning association, UNICEMP, plays a supportive role in the education and information campaign. Many voluntary organizations provide counseling. The government national commission on AIDS set up a free telephone service where experts are available to answer questions from the public. But although 18,000 calls were made in the 1st 6 weeks of opening, hardly any inqueries at all came from those most at risk--the drug users.

Christopher Ham

Although both are publicly owned and financed, the health care systems of England and Sweden are widely different in levels of funding, patterns of resource allocation, and types of planning and management. In England, control is more closely tied to national government; in Sweden, it is shared between national and local governments. A comparative analysis of decision making in the two systems reveals critical differences in determinations of how resources are allocated among competing interests, and how resources are used. Interestingly, as the English move toward more decentralization, the Swedes are considering greater central controls, but, in any event, convergence is unlikely.

Sophie Body‐Gendrot

The rehabilitation of Manhattan's Lower East Side during the last few years has occasioned bitter fights between several ethnic groups. The article analyses the practical and symbolical means used by the Portorican population in order to appropriate a space they considered as being theirs. The cultural factor is a stake in itself as each ethnic group endeavors to mark out and defend a socio-historical « turf. » Symbolic conflicts may conceal other interests — they are nonetheless an end in itself. Political elements are present, too, but the way in which they come between the fighters is proof that the solutions arrived at are at best temporary.

Tejada de Rivero D

To better understand and implement the extensive World Bank study on the financing of health, this limited article was enjoined to discuss salient features of the study and their potential for implementation. With technology for diagnosis and treatment driving health costs up, we are left with still affordable and all around more effective programs on protection and prevention that would be more cost- and health effective in a world where financial health resources are static or being cut back. Health programs and hospitals are generally inefficient with an underutilization of peripheral services. A redesign of integration systems is discussed. 4 policy reforms do, in effect, constitute a positive and feasible agenda. All of these policies will require great political commitment for their unpopularity. 1st, charging users of health services except those truly unable to pay is deemed more just. 2nd, provisions of insurance or other risk coverage (e.g. social security) need expansion. 3rd, effective use of nongovernment resources, the most vague policy reform, is discussed in terms of its implementation. 4th, decentralization of government health services is a prerequisite for achieving significant reform in financing the services. The main point of the World Bank study is active community participation which stops the paternalistic government-mendicant demanding populace pathology that is common today. A special study is suggested which would involve the World Bank and other internal organizations in analyzing the financial and technical support furnished to strengthen, endorse, and empower the reform policies.

Joshua A. Fishman, Stacey Churchill

This book provides an overview of the principles used by policy makers in western industrialized countries as they seek to meet the educational needs of cultural and linguistic minorities as diverse as Australian aboriginal peoples, resident foreign workers in Western Europe and Francophone minorities in Canadian provinces. This is a synthesis of information gathered in more than 30 national case studies and consultants' reports prepared for an OECD-sponsored study entitled: Finance, Organisation and Governance of Education for Special Populations. Drawing on this data, the author shows that current policies fit within a relatively simple framework of development by stages, each stage determined by the assumptions used in defining the educational problem to be solved. At the lower end of the scale, methods are borrowed from special education of the mentally retarded; at the upper end, the minorities are treated as equals or near equals in mature bilingual and multilingual nations such as Finland or Switzerland. The emphasis is on showing how policy makers grapple with tradeoffs to determine the best policy mix, such as between centralization and decentralization or between financial incentive schemes and direct regulation, in order to ensure adequate educational services for the minorities. The entire analytical framework is shown to fit within an integrated model linking minority aspirations, public attitudes and governmental policy responses.

Julio Frenk

The Word Bank Study "Financing Health Services in Developing Countries: An Agenda for Reform" is centered on a thesis of decreased government responsibility for financing health services. The study points out that more basic medical services are needed for the poor, but the aged and increased urbanization are forcing the application of more finances into hospitalization services. The World Bank study incorrectly assumes that the above problem is due to an epidemiologic polarization of rich vs. poor and that the only benefits from curative medicine are private, not societal, benefits. The proposal stemming from these assumptions financially separates curative from preventative services, regardless of its proven costliness and inefficiency. The 4 suggested specific World Bank reforms are: 1) charging fees for the use of health services; 2) provision of insurance or other risk coverage; 3) effective use of nongovernment resources, i.e. private practices, midwives; and 4) decentralization of government health services. These are interesting, although imperfect, solutions to the pressing problem of health care finance. The largest issues may be problems from the fragmentation of health services, cost inflation, and lack of effective controls--issues that are not dealt with in the World Bank study.

S. Abraham Ravid

0 Until more than a decade ago, financial economists typically explored problems of capital structure and dividend policy under the assumption that operating cash flows or investment decisions were exogenously determined, either with certainty or with an endowed, known distribution. Micro and macro-economic theorists, on the other hand, discussed what might be called operating income maximization, and treated as irrelevant the origin of the funds they allocated between labor and capital. It is now the consensus, I believe, that although these approaches constitute important simplifications, they may obscure some of the more important activities that take place in the firm. Interactions of production and financial decisions have thus been the focus of many recent studies. This research is extremely important for financial decision makers. If indeed it turns out that there are economically significant interactions between production and financing, then proper financial management may be vastly more difficult than typically portrayed in modern textbooks. Most of what is taught in capital budgeting, for example, is based on separation of investment and financing. If in reality this is not the case, then decentralization of the firm's operations can not be maintained, and all decisions will have to be made at the same time. Indeed, the many papers described here show how investment decisions, product pricing, labor negotiations, and market power may all be significantly related to the choice of capital structure. While this survey represents an attempt to assess the economic significance of each interaction, it must be emphasized that, as a casual glance at the references should reveal, we are dealing with on-going research that is not, as yet, supported by sufficient empirical evidence to yield definitive answers.

Gustavus J. Simmons

No abstract is available for this record.

Susan Landau

The game is simple and apparently paradoxical: Prove you know something— an ID number, an access code—without revealing even a single bit of the information itself. The importance is obvious: from credit card numbers to computer passwords, we are increasingly reliant on the secure electronic transmission of what are known as signatures. Yet how can one transmit a signature without potentially revealing to an eavesdropper—or an unethical vendor—all the information he needs in order to masquerade as the sender? Three Israeli computer scientists—Uriel Feige, Amos Fiat and Adi Shamir, of the Weizmann Institute—figured out how to play the game, called zero knowledge proofs of identity. They publicized their result at conferences, and they applied for U.S. patent protection. Ironically the United States said disclosure was detrimental to the national security, and imposed a secrecy order. The three Israelis sought relief, and, with intervention from powerful sources, they got it. Though no one will say for certain, it appears that the National Security Agency (NSA), the government decrypter of secrets, stepped in to help. What the research is, and why the NSA had reason to involve itself, is the story we present here. The technical part has its genesis in the work of Stephen Cook and Richard Karp of the early seventies. Our model of a computer is a RAM, a Random Access Machine. At issue is complexity: on a problem of input size m, how many steps does it take as a function of m to solve the problem? Certain problems are easy; by the obvious method, two m x m matrices can be multiplied in O(m 3) steps (although there are considerably more sophisticated algorithms which require only O(m2-376) steps). Other problems are less obvious. The crucial distinction comes between those problems with polynomial time solutions (the class P), and those which require more than polynomial time. The latter are considered, infeasible. What Cook did was to show that the question Is a boolean expression satisfiable? occupies a special place in the hierarchy of problems. It is solvable in polynomial time by a nondeterministic RAM1 (it is in NP, Nondeterministic Polynomial time), and it is as hard as any other problem in NP (it is complete). If satisfiabilit y has a polynomial time solution, so will any other problem in NP. Karp then showed that a number of combinatorial problems shared that characteristic, called NP-completeness, including kcolorability (can the vertices of a given undirected graph be colored with k colors so that no two adjacent vertices have the same color?), knapsack (given » finite set of integers «,, is there a subset which sums to an integer Kl), This article is the seventeenth in the series of Special Articles published in the Notices. The author, Susan Landau, is an assistant professor of computer science at Weslyan University. She received her Ph. D from M.I.T.; her thesis gave a polynomial time method for determining solvability by radicals. Her research interests include computational complexity and algebra.

David Chaum, Ivan Damgård, Jeroen van de Graaf

No abstract is available for this record.

Joe Kilian

Interactive proof systems are considered in which the best set of possible verifiers is restricted to the class of probabilistic log-space automata. A. Condon (1988) introduced this model and showed that if the protocols are allowed to run for arbitrarily many rounds, exponential-time languages can be proved to a log-space verifier. To better approximate the usual notion of interactive proof systems, a number of researchers have considered a more realistic, further restricted model in which protocols are polynomially bounded, both in the number of rounds of communication and in the number of computational steps allowed to the verifier. A notion of language-recognition zero-knowledge is defined for this model, and it is shown that anything provable in this model can be proved in language-recognition zero-knowledge.>

Joseph Y. Halpern, Yjoram Moses, Mark R. Tuttle

While the intuition underlying a zero knowledge proof system [GMR85] is that no “knowledge” is leaked by the prover to the verifier, researchers are just beginning to analyze such proof systems in terms of formal notions of knowledge. In this paper, we show how interactive proof systems motivate a new notion of practical knowledge, and we capture the definition of an interactive proof system in terms of practical knowledge. Using this notion of knowledge, we formally capture and prove the intuition that the prover does not leak any knowledge of any fact (other than the fact being proven) during a zero knowledge proof. We extend this result to show that the prover does not leak any knowledge of how to compute any information (such as the factorization of a number) during a zero knowledge proof. Finally, we define the notion of a weak interactive proof in which the prover is limited to probabilistic, polynomial-time computations, and we prove analogous security results for such proof systems. We show that, in a precise sense, any nontrivial weak interactive proof must be a proof about the prover's knowledge, and show that, under natural conditions, the notions of interactive proofs of knowledge defined in [TW87] and [FFS87] are instances of weak interactive proofs.