Blockchain Papers

Marilyn L. Flynn, Young-Soon Chung

No abstract is available for this record.

Alfredo De Santis, Silvio Micali, Giuseppe Persiano

No abstract is available for this record.

Mike Burmester

No abstract is available for this record.

Mihir Bellare, Silvio Micali, Rafail Ostrovsky

Quadratic residuosity and graph isomorphism are classic problems and the canonical examples of zero-knowledge languages. However, despite much research effort, all previous zero-knowledge proofs for them required either unproven complexity assumptions or an unbounded number of rounds of message exchange.

Moni Naor, Moti Yung

We show how to construct a public-key cryptosystem (as originally defined by DiNe and Hellman) secure against chosen ciphertezt attacks, given a public-key cryptosystern secure against passive eavesdropping and a noninteractive zero-knowledge proof system in the shared string model. No such secure cryptosystems were known before. A concrete implementation can be based on quadratic residuosity intractability.

Michael Ben-Or, Oded Goldreich, Shafi Goldwasser, Johan Håstad · 7 authors

No abstract is available for this record.

Alfredo De Santis, Silvio Micali, Giuseppe Persiano

No abstract is available for this record.

Oded Goldreich, Eyal Kushilevitz

No abstract is available for this record.

Uriel Feige, Dror Lapidot, Adi Shamir

In the present study, we investigated how the symmetry/asymmetry of cell division in mitotic CD34(+) cells can be evaluated by determining the plane of cell division and the potential distribution of proteins between daughter cells. The orientation of the mitotic spindle is dependent upon the positioning of the centrosomes, which determine the plane of cell division and the sharing of proteins. If the functions of unequally shared proteins are relevant to the kinetics of cell division, they could determine whether the daughter cells undergo self-renewal or differentiation. The kinetic function of the proteins of interest was investigated using a colony-replating assay and carboxyfluorescein succinimidyl ester (CFSE) staining. We used Notch/Numb as a model system, since they have a role in balancing symmetric/asymmetric divisions. Mitotic cells were examined microscopically and centrosomal markers γ-tubulin/pericentrin were used with activated Notch-1 and Numb. We monitored the first crucial divisions by CFSE staining and found an inverse relationship between activated Notch and Numb expression, suggesting a reciprocal regulation. We suggest that the subpopulations expressing activated Notch or Numb have different cell fates. To determine the influence of Notch signaling on progenitor cell self-renewal, we used the γ-secretase inhibitor N-[N-(3,5-Difluorophenacetyl-L-alanyl)]-S-phenylglycine t-Butyl ester (DAPT). DAPT influences self-renewal/differentiation outcome by affecting the frequency of symmetric renewal divisions without affecting the rate of divisions. Overall, the purpose of this study was to establish a cellular system for predicting the symmetry/asymmetry of hematopoietic progenitor divisions at the level of centrosomes and protein distribution and to investigate the influence of these proteins on progenitor cell kinetics.

Frederick T. Furlong, Michael C. Keeley

No abstract is available for this record.

Ellen M. Hufnagel, Jacob G. Birnberg, Joseph M. Katz

Problems can arise in decentralized organizations when usage-based chargeback systems are implemented to control computing resources. A case study of a company that is changing from negotiated pricing to full cost pricing illustrates the fact that concerns about fairness can arise not only with respect to specific characteristics of the chargeback system (e.g., understandability, controllability), but also as a result of central management policies governing internal transactions between the users and MIS. In particular, this examination identifies three factors that affect the fairness perceptions of autonomous divisional managers: (1) a high degree of interdependence between user divisions and MIS such that the behavior of MIS could have a significant impact on divisional performance; (2) restrictions on divisional managers’ freedom to purchase computer services from external sources; and (3) the tendency for full cost to exceed market prices early in the life of a data center. A dual pricing approach may be an interim solution to reduce conflict and improve user perceptions of fairness.

R.P. Mihajlović, Lj.V. Mihajlović, V.J. Vajgand, Lj.N. Jakšić

No abstract is available for this record.

Andrew Campbell, Arndt Sorge, Mark J. Warner

No abstract is available for this record.

Katherine Samolyk

Although the recent performance of the U.S. macroeconomy is being hailed as "the longest modern peacetime expansion s n failures of depository institutions have been closely linked to certain depressed productive sectors in the country. The most stark examples can be found in the depressed farm-belt and oil-producing regions. Observations indicate that financial firms do not or cannot diversify against industry-specific risk when choosing their loan portfolios. Such behavior may be explained by extensive government regulation of the industry's scale and scope or by technological costs of intermediating credit that encourage specialized lending by region or by industry. This paper does not attempt to formally explain why depository institutions engage in specialized lending; rather, it examines some implications of regional and sectoral banking in terms of macroeconomic perf~rmance.~ It considers the short-run implications of bank-capital immobility when banks produce real services in channeling the flow of funds into investments. We illustrate how regional banking conditions can affect the mix of aggregate investment and the level of future aggregate output in the absence of macroeconomic fluctuations. Given the current deregulatory trend in structural policy changes, the nature of the financial services industries has come under intense scrutiny. Recent banking literature has formalized how financial contracts are related to imperfect information. A recurring theme has been that when information is costly, the quantity and nature of external finance has allocative consequences. Diamond (1984) demonstrates how financial intermediaries (hereafter referred to as banks) can improve the efficiency of capital markets by diversifying and thus minimizing information costs; however, perfect diversification makes bank capital and the dispersion of bank asset returns irrelevant to bank portfolio choice. These strong informational assumptions allow the intermediation process to work more smoothly than we observe. If these conditions are not met, bank capital and the risk of bank assets affect bank profitability. Bernanke and Gertler (1987) show how the inability to eliminate variability in portfolio returns implies that "health" of a'bank's balance sheet can affect the flow of funds to risky bank investments. In their model, depositors cannot observe the ex-post returns on bank projects at any cost and bank capital must absorb random asset returns; insufficient bank capital may constrain banks from investing in risky but profitable investments. In a similar framework, Samolyk (1989) examines how the interest-rate risk associated with the maturity transformation in bank portfolios affects bank asset management. This paper will analyze the implications of imperfect information for investment in a decentralized banking ~ystern.~ We present an intertemporal model of banking similar to that of Bernanke and Gertler. Bankers possess a specialized technology that allows them to channel resources to investment projects that would not be funded in direct credit markets. They also have information about their portfolio returns. Unlike Bernanke and Gertler , this analysis attempts to incorporate the notion that there is more than one productive sector in the economy. We assume that in the short run, bank

Mike Burmester, Yvo Desmedt

The proof of soundness for many zero-knowledge schemes has been given in an incomplete way. We discuss the consequences.

Edward Turos, James E. Audia, Samuel J. Danishefsky

No abstract is available for this record.

George Cybenko

No abstract is available for this record.

Richard Pomfret

ASIAN PERSPECTIVE, Vol. 13, No. 2, Fall-Winter 1989, pp. 35-53 TEN YEARS OF DIRECT FOREIGN INVESTMENT IN CHINA Richard Pomfret In the late 1970s the People's Republic of China (PRC) re­ versed its economic development strategy, ending three decades of economic isolation by adopting the Open Door policy. The most dramatic component of the new strategy was the June 1979 Law on Equity Joint Ventures which permitted direct foreign investment (DFI) in the PRC for the first time. Foreign capital had, of course, played a significant role in other coun­ tries' economic development before 1979, but the PRC decision came at a time when many developing countries were rejecting foreign investors or, if they sought foreign funds, they preferred loans, which did not pose the same perceived threat to economic independence as DFI involving foreign control. In this respect China was ahead of the times, as the post-1982 Debt Crisis revealed the dangers of loans as sources of external finance and stimulated a more favorable reassessment of DFI by capital­ scarce nations. China also led the way among communist coun­ tries in permitting DFI, and the path has been followed since by the USSR, other East European countries, and the communist nations of Indochina.1 The Chinese experience with DFI is thus of interest both in itself, as a new move by the world's largest nation, and for its lessons for developing countries and for communist states. Because DFI involves a time horizon measured in years rather than months and because the inevitable initial uncertainty slowed foreign investors' response to the 1979 Law, some time had to elapse before an assessment of the Chinese experience 1. The USSR passed a joint venture law in January 1987. Vietnam adopted a law permitting DFI in June 1988 and Laos followed in the next month. 36 Richard Pomfret with DFI could be made. Ten years is an arbitrary but reasonable length. Moreover, the tenth anniversary of the June 1979 Law was marred by the massacre in Tiananmen Square and subsequent repression, which may change the DFI situation as potential foreign investors reassess their views of the PRC as a place to do business. This paper describes and evaluates the Chinese experience with DFI between 1979 and 1989. Many features are, of course, specific to China—the lure of the billion person market, the absence of direct colonial experience, etc.—but others are predictable consequences of China's resource endowment, level of economic development and policy choices. The paper examines the types of joint ventures (JVs) which have been formed, their characteristics in terms of size distribution, type of activity, nationality of foreign partners, determinants of success, and the role of policy in all this. The situation has changed over time as foreign investors have learned more about operating in China and as Chinese attitudes and policies have changed; the most useful distinction in this respect is between the situation before and after October 1986 when important modifications in the Joint Venture Law were announced. China's Open Door Policy Adoption of the Open Door policy represented a dramatic shift from China's previous inward-oriented development strategy. This section describes the four elements of the new strategy: trade policy, the Joint Venture Law, exchange rate and macroeco­ nomic policies, and the spatial dimension. Meanwhile, China was also undertaking far-reaching domestic reforms in agriculture and industry which were changing the organization of produc­ tion and the role of central planning. This paper is not concerned with these economic reforms, but they are important back­ ground events. Before 1979 China's trade policy was driven by imports and was highly centralized. Exports were determined by the amount needed to pay for imports, which were the shortfall between planned needs and domestic availability of each good. International trade was conducted by twelve foreign trade cor­ porations (FTCs), who insulated the domestic economy with its fixed prices from market-determined world prices. In Decern- Ten Years of Direct Foreign Investment in China 37 ber 1978 the Central Committee of the Chinese Communist Party rejected this approach, and by 1984 foreign trade decisions had been decentralized and controls over imports and exports...

Tamás Bácskai

The Hungarian banking system developed from the first third of the nineteenth century along the continental path, leading to the predominance of universal banks, the department stores of finance. This system of a large number of small banks with numerous branches, a sizable part of them at county and town levels, was controlled by a handful of big banks that were tightly intertwined with large foreign banks. This situation created many well-trained and broadly-skilled bank officers because, especially in the provincial banks and in branches with a limited staff, the bank employees had to be jacks of all trades, mastering all banking and stock exchange operations. Due to the fact that the Association of Banking Employees, a trade-union-like organization, had a strong left-wing audience which had considerable influence among bankers, the higher echelons of banking staffs consisted largely of pro-Allies liberals who had not been associated with Nazism. Thus, to a considerable extent, the new regime was able to draw its banking cadres from professionally well-trained, and politically loyal or neutral people. From 1949 on, even after the filling of the controlling posts with cadres of the labor movement, the lion's share of the former banking staff remained in lower posts as deputies of the new upper-level managerial staff, or in influential advisory jobs. Thus, the correctness and the professionality of banking operations, accounting, calculation, compilation of balance sheets, correspondence, both domestic and foreign, has been maintained at very high standards. Nevertheless, by having eliminated former top-level managers to a large extent, there was and is a scarcity of bankers who are specialists in allocating loans so as to optimize the safety and profitability of a portfolio. This lack was not obvious until the present decentralization because, even after the reform of the economic mechanism in 1968, the autonomy of the banks continued to be severely curtailed. There is a justified hope that Hungary can fill this gap since, from 1951 on, there has been university training for banking, and

Christopher Bond, Cynthia L. Raehl, Todd Franke

This study evaluated hospital demographics, staffing, pharmacy variables, health care outcomes measures (severity of illness-adjusted mortality rates, drug costs, total cost of care, and length of stay) and medication errors. A database was constructed from the 1992 American Hospital Association's Abridged Guide to the Health Care Field, the 1992 National Clinical Pharmacy Services database, and 1992 mortality data from the Health Care Financing Administration. Simple statistical tests and a severity of illness-adjusted multiple regression analysis were employed. The study population consisted of 1116 hospitals that reported information on medication errors and 913 hospitals that reported information on medication errors that adversely affected patient care outcomes. We evaluated factors associated with the 430,586 medication errors and 17,338 medication errors that adversely affected patient care outcomes. Medication errors occurred in 5.07% of the patients admitted each year to these hospitals. Each hospital experienced a medication error every 22.7 hours (every 19.73 admissions). Medication errors that adversely affected patient care outcomes occurred in 0.25% of all patients admitted to these hospitals/year. Each hospital experienced a medication error that adversely affected patient care outcomes every 19.23 days (or every 401 admissions). The following factors were associated with increased medication errors/occupied bed/year: lack of pharmacy teaching affiliation (slope = 0.8875, p=0.0416), centralized pharmacists (slope = 1.0942, p=0.0001), number of registered nurses/occupied bed (slope = 1.624, p=0.032), number of registered pharmacists/occupied bed (slope = 25.0573, p=0.0001), hospital mortality rate (slope = 2.8017, p=0.0192), and total cost of care/occupied bed/year (slope = 0.01432, p=0.0091). Factors associated with decreased medication errors were location in the Mid-Atlantic census region (slope = -1.5182, p=0.03), affiliation with a pharmacy teaching program (slope = -1.0252, p=0.0349), decentralized pharmacists (slope = -0.9843, p=0.0037), and number of medical residents/occupied bed (slope = -1.478, p=0.0014). There was a 45% decrease in medication errors (1.81-fold decrease) in hospitals that had decentralized pharmacists, compared with hospitals that had centralized pharmacists. In addition, there was a 94% decrease in medication errors that adversely affected patient care outcomes (16.88-fold decrease) in hospitals that had decentralized pharmacists compared with hospitals that had only centralized pharmacists. Based on previous field studies and our findings in 1116 hospitals, it appears that one of the most effective ways to prevent or reduce medication errors is to decentralize pharmacists to patient care areas. The results of this study should help hospitals reduce the number of medication errors that occur each year.

Michael Duff

No abstract is available for this record.

Robert P. Inman

No abstract is available for this record.

Robert P. Inman

No abstract is available for this record.

J.M. Criado, J. Málek, A. Ortega

No abstract is available for this record.