In this paper, a non-interactive zero-knowledge proof scheme is proposed for secure identification in wireless networks, and it uses a timed oblivious transfer technique to enable a single verifier to identify multiple provers. The verifier and the prover do not need to be synchronized in this scheme. This scheme also enjoys the distance-bounding property which makes the proposed scheme invulnerable to the relay attack. We propose to use the order statistic for the detection of relay attackers. We show that it is optimal in terms of minimum variance. Finally, we shed some light on implementation issues of our proposed scheme.
Zero knowledge sets is a new cryptographic primary in- troduced by Micali, Rabin, and Kilian in FOCS 2003. It is intensively investigated recently. However all schemes follow the basic frame by Micali et al. That is, the schemes employ Merkle tree as basic frame and mercurial com- mitments as commitment units to nodes of the tree. The proof for any query constitutes of an authentication chain. We propose in this paper a new algebraic scheme that is completely different from all existing schemes. The new scheme is computationally secure under standard assump- tion: Strong RSA assumption. It employs neither mercurial commitments nor tree frame as all previous schemes did. In fact, the prover (also as the committer) in our construc- tion commits the desired set without trapdoor information, which is another important difference from the previous ap- proaches.
BACKGROUND: The Ministry of Defense budget constitutes 16% of the state budget. The budget for the Ministry of Health and for civilian health care is derived from the state budget. The health care funds receive their budgets from several sources. The capitation formula, which is determined by law, is the main factor that affects the size of the budget each fund receives. OBJECTIVE: The objective of this study is to describe the manner of planning, managing, monitoring, and controlling the budget allocated to medical services, which is a public budget for soldiers. METHODS: Several parameters are suggested for comparison, including the interface with the civilian health system, the method for budgeting a health care system, possible results of managing a medically centered budget, and the possibilities for monitoring the provided services. We also examine the potential for decentralization of authority. CONCLUSIONS: Managing the budget and locating appropriate alternatives, as well as the availability and accessibility of medical services, are important for procurement and for forming contracts with both military and civilian systems. Turnover based on updated information might serve to improve future health services.
We provide the first proof of that for every language L isin NP there exists an O(1)-round computational zero-knowledge argument with polynomial precision for L. Our result assumes that ratio of running-time of any adversary verifier in some same verifier round of any two different executions of the argument is bounded by nalpha, where n is secure parameter and alpha is any predeterminate constant. Such verifiers are called restricted verifiers. Precise zero-knowledge was introduced by Micali and Pass in STOC'06 (They used the term "local zero-knowledge" there.) and they constructed some omega(1)-round polynomial/linear precise zero- knowledge protocols for NP and hence left an open problem how to construct O(1)-round polynomial/linear precise zero-knowledge protocols. By providing a precise simulator for Barak's O(1)-round non-black-box zero-knowledge argument, we prove that the argument is polynomial precise.
In this paper, a property rights model for electric transmission is proposed and its properties analyzed. The proposed rights, called "border flow rights," support financial hedging of transmission risk and merchant transmission expansion through associated financial rights, called "contracts for differences of differences." These financial rights allow for forward trading of both energy and transmission by a unified exchange, avoiding the bifurcation in current markets between decentralized long-term energy trading and centralized long-term transmission trading. Such long-term trading can help to support the financing of both generation and transmission assets. We consider incentive properties of such a right in the absence of lumpiness, economies of scale, and market power.
European finance is becoming increasingly cross-border, while the European architecture for safeguarding financial stability - including decision-making processes for providing financial-stability public goods - have remained decentralized with some explicit mechanisms for coordination across countries. Policy makers are aware of the limitations of the existing institutional setting, but opinions on how to proceed, including on burden sharing, are lining up along national and regional political lines with less attention paid to European needs. This paper applies the 'economics of alliances' to examine these European policy challenges. The paper establishes benchmarks for assessing the ability of Europe's existing institutional architecture to efficiently allocate resources to safeguard the EU financial system against systemic threats to stability, such as the insolvency of a pan European bank.
There is general consensus that coordination and integration are needed to achieve efficient outcomes while distributed decision power and autonomous actions are essential to develop innovative responses. These dual requirements for operational optimization and ongoing business innovation capture the essence of organizational ambidexterity as the means to sustain performance over time when environmental conditions change. This paper incorporates strategic management and organization theoretical rationales in a model that combines elements of integration and experimentation in the strategy making process and thereby extends the evolving literature on the ambidextrous organization. The performance relationships of the ambidextrous integrative strategy making model are investigated on the basis of a cross-sectional sample of 185 business entities operating in different manufacturing industries. Results of structural equation analyses indicate that superior performance in the ambidextrous organizations is associated with efficiencies derived from adherence to centralized strategic planning and effectiveness generated by decentralized innovative behavior through participation and autonomous actions. The study enhances our understanding of ambidexterity as the result of combined strategy making processes that balance the needs for economic efficiency and organizational adaptability.
Elmer S. Soriano, David M. Dror, Erwin Gaspar A. Alampay, Jolande
A sustainable health reinsurance system can be fashioned for the informal sector by mobilizing social and economic forces operating within individual communities. The economic analysis in part 1 of this book draws conclusions from success stories in industrial countries and failures in low- and medium-income countries. This analysis leads to the premise that decentralized development of microinsurance units, operating in a market segment left out by for-profit health insurance firms and by national schemes, can be stabilized financially through their affiliation with a reinsurance facility-Social Re' (part 1, this volume; Dror and Duru 2000, pp. 30-40; Dror 2001). Dror, Preker, and Jakab, in chapter 2 of this book, explain how the sociological dimension would theoretically affect the performance of a microinsurer. Findings of the Institute of Medicine reaffirm the active interplay of biology, psychology, behavior, and society in determining people's health attitudes. The institute further reports that, although people's attitudes and actions can readily be altered, these changes need support and reinforcement over time to guarantee better health. Attitudinal and behavioral changes are best prolonged through interventions at multiple levels, from the individual to society at large (Institute of Medicine 2001, pp. 1-1-1-8). Efforts are required to address the psychosocial factors that influence health status, including, for example, proposing measures such as microinsurance to persuade individuals to accept a healthy way of life and permanently modify their health behavior. Microinsurance schemes provide individuals, households, and communities mechanisms for financing their health through group risk-pooling mechanisms, leading to a sustained improvement in their access to health services. Higher up on the social scale, well-evaluated interventions at the organizational level should be encouraged, giving credit to organizations' vital role in influencing individual behavioL Still farther up the scale, community involvement in health-promotion strategies should not be overlooked, because some disease-related factors that are beyond an individual's capacity to modify can be significantly minimized through community efforts. Community empowerment, social support, and other values that protect members from stress are strengthened through community-level interventions. Finally, interventions at the societal level recognize the role of collective organizations influencing individuals' everyday existence (Institute of Medicine 2001, pp. 1-1-1-8). Underlying assumptions are that members' affiliation with microinsurers is voluntary (individuals can join, stay enrolled, or withdraw at will) and that microinsurers will voluntarily join Social Re. A clue is therefore needed about the considerations that shape individual and collective choices. According to one opinion, The underlying economic motivation for joining a microinsurance unit is assumed to be a desire to seek reciprocity in sustaining risk-sharing arrangements among essentially self-interested individuals (Dror and jacquier 1999, p. 79). This assumption implies that joining a microinsurance unit (and Social Re) is a predictable, rational economic choice by self-interested individuals to maximize total utility (optimal choice theory), and an act of reciprocity, in which giving and getting are somehow linked. According to the utility motive, people will join if they can benefit from joining. However, considering that many people will pay a health insurance premium without getting any cash benefits (if they stay healthy), is it really clear what each individual would consider as his or her exact utility from being insured? As Herrnstein points out, because utility cannot be directly observed, it must be inferred from behavior, from the choices individuals make. Thus, utility is synonymous with the modem concept of reinforcement in behavioral psychology (Herrnstein 1997, p. 226). Dror and Jacquier mention a second motive for joining a microinsurance unit: people's desire to improve their health by controlling their living and working conditions. This control is linked to a deep-rooted human need to seek voluntary and repeated interaction with others in daily life (Dror and Jacquier 1999, p. 80). These interactions may provide material reciprocity or they may reflect altruistic, nonmaterial interactions. The three authors mentioned above suggest that, to understand how microinsurers can attract and retain their clients, they have to know what shapes their clients' behavior in their specific operating context. The same reasoning applies to a microinsurer's decision to affiliate with Social Re. Since Social Re will be piloted in the Philippines, this examination will be done with reference to that country and culture. The rest of this chapter will provide an overview of the social and institutional structure of Philippine rural and informal society and the attitudes toward solidarity, risk, and insurance that influence choices and help shape the role of microinsurance. This role is quite different from what could be conjured from classical economic theory on utility, as will be shown. This analysis leads to the conclusion that in the rural Philippines, the introduction of insurance and reinsurance hinges as much, perhaps more, on the structure of society than on the profile of risks and the existence of a market for insurance.
Abstract We present a spatial model of a city with two unequally productive jurisdictions. City residents bear a commuting cost to work in either of the two jurisdictions. Each jurisdiction must finance a public budget with a wage and a head tax. We compare the first best optimum to tax decentralization. From the total welfare viewpoint, tax competition is always inefficient. However, majoritarian local governments may prefer the inefficient tax decentralization to the first best.
In the differential diagnosis of supraventricular tachycardia, pacing maneuvers or observation rarely provide a diagnosis when used individually.1 The introduction of transcatheter therapy for cardiac arrhythmia transforms electrophysiology from an exclusive, scholarly, almost Talmudic, field to an interventional goal-oriented field where successful elimination of the arrhythmia by âburningâ often serves as âproofâ of the arrhythmia mechanism (Learning by Burning). In a series of papers by Callans et al.2â4 published in this Journal, the term âlearning while burningâ was coined, emphasizing that in contrast to the goal oriented approach, ablation procedure is indeed a powerful tool for understanding the interplay between anatomical substrate and the pathophysiology of clinical arrhythmia. The authors in the present Journal article5 put a new twist on that concept by utilizing junctional beats induced during ablation procedure of AV nodal slow pathway modification to gain a new insight to the differential diagnosis of atrioventricular node reentry tachycardia (AVNRT) versus junctional tachycardia (JT). The authors should be applauded for a meticulous execution of the study protocol and a rigorous validation of their findings that showed convincingly that the mean H-A during JT is shorter than the mean H-A during AVNRT and that the mean delta H-A (defined as retrograde H-A during ventricular pacing minus H-A during tachycardia) is negative during AVNRT, as opposed to positive during JT. In the study design, both AVNRT and JT were induced in each patient. When these measurements were compared on an individual basis (meaning that every patient's measurements during AVNRT were compared with his or her own measurements during JT controlling for variability between patients), these findings hold true in most patients (see Figs. 2 and 3). How can we explain these finding based on our present knowledge about the electrophysiological properties of these arrhythmias? AVNRT is the most common cause of supraventricular tachycardia in patients referred for electrophysiological study (EPS).1 The âcommon,ââtypical,ââslow-fastâ type is present in over 80% of all cases of AVNRT.6 In a simplistic model, AVNRT results from reentry involving two anatomically distinct AV node structures7,8 (i.e., âslowâ and âfastâ pathways). In âslow-fastâ AVNRT, the reentry circuit consists of anterograde conduction through the slow pathway and retrograde conduction by the fast pathway with the earliest retrograde atrial activation in the âfast pathway regionâ at the apex of the triangle of Koch, recorded on the His-bundle electrogram from the right septum.9,10 Unfortunately, life is not that simple: the three-dimensional anatomy and cytoarchitecture of the AV junction is complex11,12 and the exact location of the atrionodal connections and slow and fast pathways are still controversial. Although several elegant models based on functional characteristics of different areas of the compact AV node and surrounding structures were proposed to explain dual-AV node physiology, the sheer bulk of the literature on the subject and the ongoing debate attest that none of them is proven.13,14 In as many as 40% of the patients with AVNRT, there are multiple AV nodal pathways.15 Even in patients with typical AVNRT, recording with close-spaced electrodes in the His, coronary sinus (CS), and the slow-pathway areas has shown that there is heterogeneity of the retrograde fast pathway conduction pattern.16 Recording of the His bundle potential from the right and left sides of the septum has shown that the earliest retrograde atrial activation during AVNRT is most often recorded on the left side of the septum.17 Thus, it is not surprising that there is a considerable variability in H-A intervals in patients with typical AVNRT, making it difficult at times to differentiate between typical AVNRT and other arrhythmias (including JT) based on H-A interval alone. According to the slow-fast pathway model, the retrograde atrial activation sequence during right ventricular pacing at the tachycardia cycle length, immediately after typical AVNRT, propagates retogradely from the His bundle through the lower common pathway to the fast pathway, and should be similar to the activation sequence during typical AVNRT. Retrograde H-A interval during ventricular pacing (H-Ap; measured from the end of the most proximal His potential to earliest A) is the sum of retrograde conduction time of the lower common pathway and the retrograde fast pathway. The H-A of typical AVNRT (H-At) according to this model is retrograde conduction time of the fast pathway minus anterograde conduction time of the lower common pathway. The difference between H-Ap and H-At (so called delta H-A) equals retrograde plus anterograde conduction time of the lower common pathway13 (assuming that the retrograde fast pathway conduction time is identical during pacing and AVNRT). A positive delta HA suggests that a lower common pathway is present. A negative delta HA, which, in fact, was found in the present study5 and by others,18 cannot be explained by this simple model. Although there are several explanations for this phenomenon, including difference in conduction velocity, activation path,19 and a combination thereof,13 a negative delta HA probably reflects a very short or an absent lower common pathway. Automatic JT as described by Coumel20 is a rare arrhythmia seen mainly in the pediatric population21 and postcardiac surgery21,22 and very rarely in adults.23 In the few cases studied, abnormal automaticity within or in close proximity to the His bundle was found.24â26 JT is frequently seen during radio frequency ablation using the AV node modification by slow pathway approach. In fact, the presence of JT is associated with successful slow pathway ablation.27,28 The pathophysiology of JT during ablation is thought to be enhanced automaticity due to heating of the tissue29,30 or local release of norepinephrine.31 Studies in pig and rabbit heart models have shown that heating in a discrete area located in the middle of the triangle of Koch that was located in close proximity to the compact AV node induced JT. In that area, no slow pathway potential was seen and it was distant from the site of earliest retrograde atrial activation. There was a large variation between individual animals regarding the location of these sites.30 In canine blood-perfused atrioventricular node preparations, JT was induced by heating anterior to the CS os with the earliest retrograde atrial activation site at the His-potential recording site or in the middle of Koch's triangle. After interruption of the posterior input to the AV node, atrial activation during JT spread from the low posterior to the high anterior septum.29 In humans, VA block during junctional ectopy is a harbinger of AV block in patients undergoing RF ablation of the slow pathway,27 suggesting that the retrograde atrial activation during JT may involve the His area or the common lower pathway. However, in that same paper, the authors observed that âVA conduction should be expected during the junctional ectopy that accompanies slow pathway ablation, even when there is poor VA conduction during baseline ventricular pacing,â and that the AV block was proximal to the His.27 These astute observations suggest that the site of VA conduction during JT is proximal to site of VA block during ventricular pacing. Wagshal et al.32 reported that higher temperature lesions simultaneously abolish all slow pathway activity as well as the focus of JT, which suggests that the JT source is located or triggered by slow pathway tissue. In a study by Lee et al.,33 atrial activation sequences were assessed by comparing H-A interval (measured at the high right atrium) during various forms of AVNRT and JT induced by ablation. In 27 patients with slow-fast AVNRT, H-A during JT was shorter than during AVNRT: 58 ± 24 msec compared with 68 ± 21 msec, respectively (P < 0.01). In the present study,5 a similar trend in mean H-A interval was observed: 35 msec versus 54 msec during JT and AVNRT, respectively. These findings call into question the concept that JT seen during RF ablation originates or has an exit point near the His area as described in the rare âde novoâ automatic JT.24 Obviously, if a junctional beat originates near the His, distally to a common pathway, the H-A interval during JT will be longer than H-A interval during AVNRT that has a more proximal turn-around point to the fast pathway. In that situation, one would expect near-zero delta H-A in JT and positive delta H-A in AVNRTâin contrast to the finding of present5 and other33 studies. Studies in animal models and high resolution mapping in humans have demonstrated several mechanisms that can account for the shorter H-A interval during JT compared with AVNRT: changes in activation sequences that may cause direct activation of the atria, compact AV node,29 anisotropic spread from one more AV nodal transitional zone,34 fibers connecting to the fast pathway,35 or fibers connecting the slow pathway ablation area directly to the fast pathway in a more proximal location.33 Local heating may cause an increase in conduction velocity due to a direct effect30 or adrenergic stimulation. A recent study in a canine complete AV block model has shown that the application of RF energy caused a shift from the distal portion of the AV junctional area to a more proximal one. This enhanced junctional automaticity was suppressed by esmolol but not affected by atropine.31 In conclusion, differential diagnosis of a short RP tachycardia can be challenging. The paper by Srivathsan et al.5 adds a valuable new technique regarding the diagnosis of JT versus AVNRT, as well as provides insight into the electrophysiological mechanism of this fascinating and elusive arrhythmia. Further research is needed to ascertain whether these findings can be extended to the clinical forms of JT. Acknowledgment: The author would like to thank Dr. Shaul Atar for critical review of the manuscript.
Formal organization is often seen as opposed or resistant to change, in theory as well as in practice. Drawing primarily on the philosophy of Gilles Deleuze we argue that the reverse is true â that organization is itself a dynamic quality and that change and organization are imbricated in each other. We expand several key concepts of this philosophy in relation to organization (the multiplicity of order and the multiplicity of organization, strata and meshworks, virtuality and multitude) all of which draw attention to the unstable but ever-present forces that subvert and disrupt, escape, exceed and change organization. This enables an understanding of organization as creatively autosubversive â not fixed, but in motion, never resting and constantly trembling.
Human organization is discussed as a social body or collection of organs and senses that create and re-create the forms and objects that constitute the human world. Organs represent process as the continuous making and remaking of passages between the body and its environment. Organs express a pre-human, impersonal force that transmits itself through the human body and its products in a generic act of making as opposed to the making of specific forms and objects. Process is discussed as the ceaseless work of alternation between the making of presence and the unmaking of absence. The work of process is illustrated through the work of three examples of human organization: the supermarket, the art gallery and the Church.
Although the semi-honest model is reasonable in some cases, it is unrealistic to assume that adversaries will al- ways follow the protocols exactly. In particular, malicious adversaries could deviate arbitrarily from their prescribed protocols. Clearly, protocols that can withstand malicious adversaries provide more security. However, there is an ob- vious trade-off: protocols that are secure against malicious adversaries are generally more expensive than those secure against semi-honest adversaries only. In this paper, our goal is to make an analysis of trade-offs between perfor- mance and security in privacy-preserving distributed data mining algorithms in the two models. In order to make a realistic comparison, we enhance commonly used subpro- tocols that are secure in the semi-honest model with zero knowledge proofs to be secure in the malicious model. We compare the performance of these protocols in both models.
Nishanth Chandran, Vipul Goyal, Rafail Ostrovsky, Amit Sahai
In STOC'05, Aim, Hopper and Longford introduced the notion of covert computation. A covert computation protocol is one in which parties am run a protocol without knowing if other parties ore also participating in the protocol or not. At the end of the protocol, if all parties participated in the protocol and if the function output is favorable to all parties, then the output is revealed. Ahn et al. constructed a protocol for covert two-partv computation in the random oracle model In this paper, we offer a construction for covert multiparty computation. Our construction is in the standard model and does not require random oracles. In order to achieve this goal, we introduce a number of new techniques. Central to our work is the development of "zero-knowledge proofs to garbled circuits," which we believe could be of independent interest. Along the way, we also develop a definition of covert computation as per the Ideal/Real model simulation paradigm.
This study examined the current decentralized system in Indonesia for increased disparities in educational expenditures across districts. It also examined the impact of these on the quality of education at public junior secondary education. The study used the most recently available data from the Ministry of National Education (MONE) and Central Bureau of Statistics (BPS) covering 1999/00 and 2002/03. These data measured district level school expenditures, demographic and socio-economic variables.The study found that the current decentralized system in Indonesia increased fiscal capacities for education at districts. Unfortunately, increases in the fiscal capacities for education led to increased disparities in education expenditures per student, creating growing gaps in fiscal capacities for education across districts. Districts which received larger general allocation funds (DAU) per capita were also more likely to allocate more funding for education, whether or not they were poor or wealthy districts. This fact was reflected by the finding that district GRDP per capita in sub-national regions of Java-Bali and Sumatera had no impact on districts' education expenditures per student. In addition, the sub-provincial districts of the Kota (more urban) and Kabupaten (less urban) also differed in the way that they allocated funding for education. The Kota in the Sumatera region tended to allocate significantly more for education than did the Kabupaten. At the same time, the Kota in Java-Bali did not allocate significantly more for education than the Kabupaten. Teacher compensation was national, so funding variance was measured by locally controlled variables. The most significant impact on student achievement were teaching and learning process expenditures (textbooks, libraries, labs, field trips, etc.). The study concluded that increased funding, combined with more efficient budget allocations, were keys to quality improvement. Policy recommendations include: a) targeting DAU transfers to reduce the gaps in fiscal capacity for education across districts; b) rewarding districts with effective budget allocations that support improved student achievement; and c) placing education closer to the center of development and security policy. Better government monitoring and district transparency is needed for this major investment. Improved policy research and reporting capacities are needed, including annual reports on decentralization policy implementation.
The rise of Antwerp and the decline of Bruges are often seen in terms of a timetable of significant events: the establishment of the English cloth staple in Antwerp in 1421; the arrival of the south German merchants with their silver in the 1460s; and finally the transfer of the Portuguese spice market to the city in 1498. The 1438 ledger of a Milanese bank in Bruges suggests that by then the south Germans were well established at Antwerp and the Scheldt fairs, exporting large quantitites of fustian. It also shows the bank's integrated commercial and financial operation based on Bruges, Antwerp, Bergen, and Middleburg.
Albert J. Jovell, Robert J. Blendon, MarĂa Dolors Navarro, Channtal Fleischfresser · 7 authors
BACKGROUND: Fifteen years ago, public opinion surveys in Spain showed substantial dissatisfaction with the health-care system. Since that time, health-care in Spain has undergone significant changes, including a decentralization of the system, an increase in spending and a change in the way the system is financed. OBJECTIVE: This study examines how Spanish citizens rate the performance of their health system today, both as compared with other sectors of society and as compared with earlier time periods. METHODS: Data are drawn from nationally representative telephone surveys of the non-institutionalized adult Spanish population (age 18 years and over). The study was carried out in two phases: October-November 2005 (n = 3,010) and January 2006 (n = 2,101). RESULTS: The majority of the Spanish population thinks the health system needs to be changed. The problems cited relate mostly to long wait times to get health-care. Nevertheless, over the last 15 years, the proportion of people who have very negative views about the health system has decreased by half. The majority believes that not enough money is spent on health-care, but few people would support an increase in taxes to provide additional funding. The survey finds the National Health System's institutions and health professionals to be more highly trusted than other institutions and professional groups in the country. CONCLUSIONS: Government policy-makers in Spain face a dilemma: the public wants more health spending to decrease wait times, but there is substantial resistance to increasing taxes as a means to finance improvements in the system's capacity.
Christian Vang Eghoff, Catherine Farvacque-Vitkovic, Alicia Casalis, Mahine Diop
Taking its outset in a description of the urban sector in Mali, this report explores the most promising entry points for future urban and municipal development. Mali is much less urbanized than other countries in the region but its urban areas are growing very rapidly. Mali's cities already play a preponderant role in creating the country's wealth. The lack of access to basic services and infrastructure lies at the heart of Mali's urban development problems. This situation is caused by a shortage of funds for urban development, which are far from commensurate with the rapid pace of urbanization. Efforts to improve urban management will have to be stepped up as part of the decentralization process and a strong Government commitment to the urban sector is strategically important with respect to economic development objectives and fighting poverty. On the basis of the review of the urban sector, this report recommends continuing efforts on two levels: (i) on the level of a limited number of individual cities through targeted activities carried out under Municipal Contracts, and (ii) at the national level through cross-cutting accompanying measures to increase resources available for urban development, promote local economic development, improve the land markets and increase the production of plots, ensure financing and functioning of basic services, reinforce cooperation between municipalities, and equip the cities with urban planning tools.