Blockchain Papers

Martin Altemeyer-Bartscher, Dirk Rübbelke, Eytan Sheshinski

No abstract is available for this record.

Carlos M. S. Figueiredo, L. L. de Aquino, A. F. Loureiro, Linnyer B. Ruiz

Self-organization is an important concept being applied to modern computer networks to achieve robust autonomous operation. In particular, Wi- reless Sensor Networks (WSNs) were conceived under this paradigm. With this concept, the network elements interact only among themselves, in a completely decentralized way, to accomplish a function for the proper network operation. However, application and management goals can change along the time, and a scheme for controlling these element interactions to adjust or change the achie- ved global behavior to a new requirement has not been explicitly addressed yet. In this work, we present a general scheme for managing this kind of network. The proposed scheme is composed by a central idea, which consists of acting over local rules guiding the element interactions according to required goals and/or QoS metrics, and a methodology, which defines a generic procedure and relates important aspects for the design of the management solutions. We de- monstrate the applicability of our scheme by presenting a case study. Resumo. Auto-organizac ¸ ˜ ao ´ e um importante conceito sendo aplicado em siste-

Muhammad Rahman Heriyadi

Sang Pemburu in Lativi represents mystical program that hunting, revealing and neutralizing a place from invisible things. By presenting an ustadz as a team, the established process and water­ pitcher utilization as a typical characteristic has shown that it is very different from other mystical programs in other television station. Initially, there are many perception rises in the collegian class as a part of society to this program. Some of them are accepting this program, some rejecting and their remains are hesitating, so that the purpose of this research is to know the perception of collegian of communication major generation 2002 to the program material of Sang Pemburu in Lativi. Perception is a meaning gift to the stimuli both in the form of events, object, and the relation obtained by drawing a conclusion of information and by interpreting a message. The factors that have a role and influence the establishment process of perception are somebody’s stimulus state, social situation or condition that rise the stimulus, and the individual perception regard to both of the physical aspect and spiritual aspect. The underlying theory to know the collegian perception to program material of Sang Pemburu in Lativi is Individual Differences Theory. It note that everybody will respon the massmedia contents based on their belief and their social values, because each individu has different attention, interest, belief and also has different value. Besides, it is added by the mind limit theory where human solve their life problems using their mind and knowledge system, but both of them are limited. Human’ mind limit are very narrow, especially in understanding any mystical things. The different thinking of each person is the other evidence of mind limitation. In this research, the researcher uses qualitative method to collect factual information in describing the existing symptoms. Type of this research is qualitative descriptive by using emic approach. The information source in this research is collegian of Communication Major of UMM generation 2002 of 12 collegians, using purposive sampling to sample intake. Data collecting technique is interview and focus group discussion (FGD). The obtained data are analyzed by qualitative descriptive analysis and by validity technique of situation triangulation data. From data analysis, it is known that indirectly materi in Sang Pemburu Program is same with other mystical program in other television station. The difference is its content, where there aresome thing looks different that is the ritual of opening, hunting, mediumisation and staking invisible fence up, and also water­pitcher utilization. There are some informants that are very disagree with what the team Sang Pemburu doing because it considers had disturb the natural balance, that is between the real world and unreal world. Yet, there also who reveal that what ever done in the program is very reasonable, because their purpose is to help others from any invisible disturbances. The difference risen from those informant explains that they response all the displayed things through mass media especially television based on their knowledge and experiences. Moreover, it has connected to invisible matter where the human mind is very limited to understand it. It can be concluded that the conviction of the invisible existence has became an absolute matter to be had before we try to understand the mystical programs on televisi such as Sang Pemburu. The existence of invisible world and its creatures is very hard to be proven logically. Moreover, indirectly, through this program it can not proof the validity of them, because the technology (camera) cannot capture nor display them really. Watch or not, it depends on the audience as the consumer of television program.

조기현

No abstract is available for this record.

Holly A. Crocker

B eginning with a broken metamorphosis, Chaucer’s Book of the Duchess attempts to resolve the scandal of gender’s visuality through its relational construction of a memorial poetics. In the Ovidian story, metamorphosis saves Alcyone from suicide; this transformation revives her and reifies her husband, changing both into sea birds. 1 Chaucer’s rendition sees Alcyone dead within three days of the return of her husband’s body. Mortality, along with its ultimate proof, death, is more visible in Chaucer’s poem than in his sources. 2 Chaucer’s treatment of the Ceyx and Alcyone narrative thus reveals a suspicion of superficial visions that is relevant to the larger composition to which it belongs. This account, like the Black and White story it presages, is a tangible arrangement of differences that are narrative, visual, and topographic. 3 Because gender difference is staked on degrees of visual distance in the Book of the Duchess , this chapter addresses the spatial arrangement of perspective across its aesthetic, religious, scientific, and philosophical contexts. The process of spatial arrangement is more relational than linear in the poem itself, so the argument of this chapter will follow the poem’s meandering path in order to address the artistic, religious, and intellectual controversies that Chaucer finesses through his creation of a powerful feminine image. These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

José Cláudio do Nascimento, Rubens Viana Ramos

Zero-knowledge proof system is an important protocol that can be used as a basic block for construction of other more complex cryptographic protocols. An intrinsic characteristic of a zero-knowledge systems is the assumption that is impossible for the verifier to show to a third part that he has interacted with the prover. However, it has been shown that using quantum correlations the impossibility of transferring proofs can be successfully attacked. In this work we show two new protocols for proof transference, being the first one based on teleportation and the second one without using entangled states.

Allison McCracken

No abstract is available for this record.

Seydou Coulibaly, Dominique Desplats, Y Kone, Karamoko Nimaga · 10 authors

La difficulte d’attirer du personnel de sante qualifie en milieu rural constitue un obstacle majeur a l’acces pour tous a des soins de qualite. Quinze ans d’experience de medecine de campagne au Mali temoignent toutefois de la possibilite, dans un contexte africain, de developper en zones rurales des pratiques de medecine communautaire, integrant soins curatifs individuels et activites de sante publique. Le mouvement des medecins de campagne au Mali s’inscrit dans le processus de decentralisation des soins, dans lequel les communautes et les Mairies jouent un role croissant : les medecins de campagne sont en effet le plus souvent recrutes par les communautes. Regroupes au sein de l’Association des Medecins de Campagne, ils adherent a une Charte commune et s’engagent a dispenser des soins de qualite et financierement accessibles. Un dispositif de qualite s’est progressivement mis en place impliquant plusieurs partenaires : une association professionnelle, une ONG de soutien, des universitaires et des gestionnaires du systeme de soins. Cet article decrit la genese de l’experience des medecins de campagne, la philosophie qui la © S Coulibaly, D Desplats, Y Kone, K Nimaga, S Dugas, G Farnarier, M Sy, H Balique, OK Doumbo, M Van Dormael, 2007. A licence to publish this material has been given to Education for Health: http://www.educationforhealth.net/ 2 sous-tend, les conditions qui l’ont rendue possible, les difficultes de mise en œuvre, les strategies pour y faire face, et l’evolution des partenariats. Il met en evidence le potentiel des professionnels de soins en Afrique pour sortir de l’impasse de soins de sante primaires limites a des maladies prioritaires, et pour offrir des reponses aux attentes immediates des communautes tout en assurant les activites necessaires a la sante publique. Financement: Le projet des medecins de campagne beneficie du soutien financier de l’Union Europeenne et de la Cooperation Francaise. L’appui technique de l’Institut de Medecine Tropicale d’Anvers est finance par la Cooperation Belge. Neighbourhood rural medicine: an experience of rural doctors in Mali English Abstract The main constraint to improving access to health services of quality in rural areas is to attract qualified health personnel in these areas. A fifteen years experience in rural health in Mali has shown that it is possible to develop community medicine practices in an African context that do integrate individual care and public health activities. The policy of decentralization of health services encouraged local communities and municipalities to recruit rural doctors themselves. An initiative of rural doctors materialized with this event as they founded a national association and adhere to the principles of a Charter to provide quality health care at an affordable cost. A mechanism of quality improvement was established with the participation of several partners: a professional association, a funding non-governmental organization, and groups of academic staff and health managers. This paper describes the evolution of the rural doctors’ experience, its philosophy, conditions that made it successful, constraints it had to overcome and the attitude of partners. It highlights the potential of health care personnel in Africa to provide primary health care well beyond traditional programs on prevalent diseases and to respond to both urgent individual needs and pressing public health requirements. Medicina rural comunitaria: una experiencia de medicos rurales en Mali Resumen Espanol El mayor obstaculo para mejorar el acceso a los servicios de salud de calidad en las areas rurales, es atraer personal de salud calificado para estas areas. La experiencia de quince anos de salud rural en Mali ha demostrado que es posible desarrollar practicas de medicina comunitaria en un contexto africano, integrando atencion individual y acciones de salud publica. La politica de descentralizacion de los servicios de salud estimulo a las comunidades locales y a los municipios a reclutar directamente medicos rurales. Una iniciativa de medicos rurales se materializo cuando ellos fundaron una asociacion nacional y se adhirieron a los principios de un Estatuto para proveer atencion a la salud de calidad y a un costo aceptable. Se establecio un mecanismo para mejorar la calidad, con la participacion de varios actores involucrados: una asociacion profesional, una organizacion no gubernamental filantropica, grupos de academicos y administradores de salud.

Jia Yu, Fanyu Kong

No abstract is available for this record.

Anne Rasmussen

The interactions between science, society and politics at work in the influenza epidemic of 1918 – a huge event – constitute an analytical frame for studying controversies which take place in times of emergency and under censorship. What was at stake in these controversies concerning scientists, experts and politicians, was the competition between forms of knowledge, facts, the provision of proofs, and the manner of their validation. Implicated in this were the linkages between publics and various regimes of truth, from popular belief to scientific proof.

Xiangdong Zhang

The local governments stand in a kind of special independence position because of the decentralization of the public finance power and the vertical personnel system,and transmute into an activity corpus of having the special benefits claim.Only by recovering the publicity,the construction or purchase of service type of the local governments can be carried out probably.

Vrajlal K. Sapovadia, Rashid Rehman

No abstract is available for this record.

최병호

No abstract is available for this record.

Shien Jin Ong, Salil Vadhan

No abstract is available for this record.

J.R. Canoy

By early 1946, an increased American flexibility regarding the pre-Nazi tradition of centralized and bureaucratically autonomous Bavarian state police would drive the occupiers to modify their original radical decentralization agenda. A series of detailed historical studies and summaries of aspects of pre-1933 and pre-1918 rural and urban police organization and operations that the Americans began requesting from Bavarian technical advisors in the summer of 1946 bear witness to this growing interest. As the Americans routinized their occupation throughout the winter of 1945–1946, this growing fund of information about the older Bavarian police tradition began to find its direct reflection in the efforts of the Public Safety officers in the U.S. Military Government to undertake a more systematic and permanent reorganization of the German police. The nature and perception of the threats to public order during the occupation were the broader context for the decisions made about police organization in 1945–1946.Keywords: American regulations; Bavarian police tradition; police organization; public safety officers; U.S. military government

T. V. Ramachandra, AV Nagarathna

Community-based natural resource management (CBNRM) is the joint management of natural resources by a community based on a community strategy, through a participatory mechanism involving all legitimate stakeholders. The approach is community-based in that the communities managing the resources have the legal rights, the local institutions and the economic incentives to take substantial responsibility for sustained use of these resources. This implies that the community plays an active role in the management of natural resources, not because it asserts sole ownership over them, but because it can claim participation in their management and benefits for practical and technical reasons1–4. This approach emerged as the dominant conservation concept in the late 1970s and early 1980s, of the disillusionment with the developmental state. Governments across South and South East Asia, Africa and Latin America have adopted and implemented CBNRM in various ways, viz. through sectoral programmes such as forestry, irrigation or wildlife management, multisectoral programmes such as watershed development and efforts towards political devolution. In India, the principle of decentralization through ‘gram swaraj’ was introduced by Mahatma Gandhi. The 73rd and 74th constitution amendments in 1992 gave impetus to the decentralized planning at panchayat levels through the creation of a statutory three-level local self-government structure5,6.
\nThe strength of this book is that it includes chapters by CBNRM advocates based on six seemingly innovative initiatives being implemented by nongovernmental organizations (NGOs) in ecologically vulnerable regions of South Asia: two in the Himalayas (watershed development programme in Lingmutechhu, Bhuthan and Thalisain tehsil, Paudi Grahwal District, Uttarakhand), three in semi-arid parts of western India (watershed development in Hivre Bazar, Maharashtra and Nathugadh village, Gujarat and water-harvesting structures in Gopalapura, Rajasthan) and one in the flood-plains of the Brahmaputra–Jamuna (Char land, Galibanda and Jamalpur districts, Bangladesh).
\n
\nWatersheds in semi-arid regions fall in the low-rainfall region (500–700 mm) and suffer the vagaries of drought 2–3 years in every five-year cycle. In all these locations, the major occupation is agriculture, most of which is rainfed or dry. The other two cases (in Uttarakhand) fall in the Himalayan region (temperate/sub-temperate climate), which has witnessed extensive deforestation in the last century and is now considered as one of the most vulnerable locations in South Asia. Terraced agriculture is being practised in these locations for a long time. The last case (Gono Chetona) falls in the Brahmaputra–Jamuna charlands which are the most ecologically vulnerable regions in the sub-continent with constantly changing landscape. Agriculture and livestock rearing are the main occupations, and there is substantial seasonal emigration for wage labour by the adult males. River erosion and floods force the people to adopt a semi-migratory lifestyle.
\nThe book attempts to analyse the potential as well as limitations of NGOdriven CBNRM endeavours across agroclimatic regions of South Asia with emphasis on four intrinsically linked normative concerns, namely sustainability, livelihood enhancement, equity and demographic decentralization in chapters 2–7. Comparative analysis of these case studies done in chapter 8, highlights the issues that require further research while portraying the strengths and limits of NGO-driven CBNRM. In Hivre Bazar, the post-watershed intervention scenario is such that farmers often grow three crops in a year – kharif bajra, rabi jowar and summer vegetable crops. Productivity has increased in the dry lands due to improvement in soil moisture levels. The revival of johads in Gopalpura has led to the proliferation of wheat and increased productivity. In Lingmuteychhu, productivity gains have also arisen, but more due to the introduction of both local and high-yielding, new varieties as opposed to increased water availability. In the case of Gono Chetona, improvements have come due to diversification of agriculture; for example, the promotion of vegetable gardens. CBNRM interventions in most cases have also led to new avenues of employment and income generation.
\nThe synthesis shows that CBNRM efforts have made significant contributions to livelihood enhancement and only limited gains in terms of collective action for sustainable and equitable access to benefits and continuing resource use, and in terms of democratic decentralization, contrary to the objectives of the programme. Livelihood benefits include improvements in availability of livelihood support resources (fuelwood, fodder, drinking water), increased productivity (including diversification of cropping pattern) in agriculture and allied activities, and new sources of livelihood. However, NGO-driven CBNRM has not met its goal of providing ‘alternative’ forms of ‘development’ due to impediments of state policy, short-sighted vision of implementers and confrontation with the socio-ecological reality of the region, which almost always are that of fragmented communities (or communities in flux) with unequal dependence and access to land and other natural resources along with great gender imbalances. Appalling, however, is the general absence of recognition of the importance of and the will to explore practical ways to bring about equitable resource transfer or benefit-sharing and the consequent innovations in this respect that are evident in the pioneering community initiatives such as pani panchayat, etc.
\nPertaining to the gains on the ecological sustainability front, Hivre Bazar and Thalisain initiatives through active participation of villagers have made significant regeneration of the water table within the village, and mechanisms such as ban on number of bore wells, the regulation of cropping pattern, restrictions on felling of trees and free grazing to ensure that in the future, the groundwater is neither over-exploited nor its recharge capability impaired. Nevertheless, the longterm sustainability of the interventions in the case of Ghoga and Gopalpura initiatives as the focus has been mostly on regeneration of resources, and less on regulating the use of regenerated resources. Further, in Lingmuteychhu and Gono Chetona, the interventions are mainly household-based and the focus has been less explicit on ecological components.
\nThe studies demonstrate the livelihood benefits to all of the interventions and significant variation in achievements with reference to sustainability, equity and democratic decentralization depending on the level and extent of community participation apart from the vision of implementers, strategy (or nature of intervention shaped by the question of community formation), the centrality of community formation and also the State policy. Case studies show that the influence of State policy is multi-faceted and often contradictory in nature. This necessitates NGOs to engage with the State in a much more purposeful way than in an ‘autonomous space’. Thus the role of NGOs in CBNRM is complementary, wherein they provide innovative experiments that the State can learn. This helps in achieving the goals of CBNRM through democratic decentralization. The book addresses the vital issues related to natural resource management and interests of the community. Key topics discussed throughout the book are still at the centre of the current debate. This compilation consists of well-written chapters based on rigorous synthesis of CBNRM case studies, which will serve as good references for students, researchers and practitioners in the years to come.

V. Matossian

Networked systems are continuously growing in scale and complexity. The technical and policy engineering challenges introduced by such a fast growth are currently addressed locally, with limited understanding of their impact on the whole. Such approaches are becoming impractical and insufficient. Next-generation networks need to address these issues by deploying adaptive and self-managing protocols and mechanisms to relax the persistent need for human-driven management. However, achieving these objectives requires conceptual, physical, and logistical modifications to existing systems and protocols. To this end, the traditional top-down approach to network and application design needs to be supplemented by understanding the bottom-up nature of evolving real-world networks.A critical issue that is significantly impacting computer networks and applications is the absence of an in-depth understanding and lack of control over the structural properties, i.e., topology, of large networks. Network topologies define the link relationships between the nodes in the network, and have a direct impact on the performance, resilience, and security of distributed applications. Large scale networks such as the Internet are the result of a time evolving process in which nodes and links between nodes are added, removed, and reconfigured dynamically. This dynamic process takes place in a decentralized manner during which nodes make local adaptations and reconfiguration decisions that optimize local properties. As a result, these local perturbations yield an emergent network that is often unstructured and complex, and have implications at the application-level, particularly impacting routing, search, robustness, and clustering. Understanding the structures emerging out of these adaptations is a complex problem part of the science and study of complexity theory and complex adaptive systems. Tackling this complex problem requires first, identifying canonical metrics to quantify the network topology and second, analyzing the impact of local perturbations of these metrics on the resulting network topology.This thesis identifies three local metrics, transitivity, assortativity, and entropy, and analyzes the impact of their perturbation on the applications of routing, search, robustness, and clustering. The local metric of network entropy is identified as a useful information theoretic measure of homogeneity of a network neighborhood degree. The metric is further used to derive a novel mechanism of clustering detection of the network topology. The overall objective of this thesis is to investigate metrics and mechanisms to better understand the evolution of the network topology and its impact on application-level functionality. The approach is based on concepts of emergence, self-organization and graph theory, and has three key aspects: (1) the identification of canonical local and global graph metrics; (2) the quantitative analysis of the impact of local perturbations on global properties; and (3) the application of the local to global mapping on the problems of routing, search, robustness, and clustering. Adaptations are performed in a decentralized manner in which local nodes use local information to add, remove, or rewire an edge to evolve the topology. Simulations based on annealing optimization are conducted to empirically determine the optimal bounds of the network structures for the selected metrics on selected networks. Further experiments on two modeled networks, random and power-law degree distributed, and two real-world networks, the Gnutella and Canadian Autonomous System networks, show that the impact of optimizing networks with fixed degree distribution on local metrics yield networks with routing, search, robustness, and clustering that are tightly dependent on the network's degree distribution. A key outcome of this thesis is the identification of network entropy minimization as a useful local rewiring strategy to decrease average path length and search cost, while homogenizing the size of network clusters and having a low impact on robustness when applied to power-law degree distributed networks that prevail in real-world networks.

Lin Hua

This paperproposes a new zeroknowledge proofprotocolofidentification which combinesthe characteristics of the ECC and zero knowledge proof.As compared with the protocol with its security based on the hard for resolving the big number problem,the proposed protocol has more advantages than the former in the quantity of computing and traffic.

Richard M. Southall, Mark S. Nagel

INTRODUCTION The 1994 Men’s World Cup generated near-capacity crowds at stadiums around the United States and resulted in relatively large domestic television audiences. Buoyed by this success, Major League Soc-cer (MLS) was founded in 1996 with several wealthy and influential owners among the league’s inves-tors (National Soccer Hall of Fame, 2005). Similarly, the unprecedented media coverage (11.4 Nielsen rating for final), record-breaking attendance figures (90,000 at the Rose Bowl for the Women’s World Cup Finals), and the United States Women’s national team’s 1999 World Cup shootout victory over China, paved the way for the Women’s United Soccer Association’s (WUSA) founding in 2001 (Women’s United Soccer Association, 2000a). Each league’s inception was hailed - to various degrees - as proof that soccer was no longer just a fringe or niche American sport, but had finally arrived as a major pro-fessional U.S. sport. For any new or existing sports league to successfully make the transition from niche to major profes-sional sport league, it must have sufficient capitalization to sustain itself until sufficient revenue is generated to cover operating expenses. This economic fact-of-life requires not only that league or individual team owners are financially and emotionally committed to long-term incremental growth, but that sponsors, league administrators, and players are cognizant of the sport’s and/or league’s growth potential. It is important to remember that all sport leagues, niche or major, are supported by the same revenue sources (i.e., ticket sales, broadcast rights, sponsorship, merchandise). However, for a niche league - with its more limited fan base - to be successful, it is critical that existing reve-nue sources are effectively cultivated and harvested. Additionally, potential revenue sources must be identified, prospected, and obtained if the league is to experience growth in sponsorship, merchan-dising, attendance, and broadcast rights. Since both MLS and the WUSA have been largely ignored by sport management scholars, this study is designed to add to the knowledge of these leagues. Exchange theory , cause-related marketing (CRM), and strategic philanthropy are the theoretical frameworks used to evaluate the leagues’ marketing successes and failures. THEORETICAL FRAMEWORKS Exchange theory applies to any successful business transaction. For any transaction to succeed all par-ties must agree that a satisfactory value exchange has occurred (Howard & Crompton, 2004). A de-sired outcome is only achieved when each party is willing to act in the best interest of all stake-holders or participants (Blalock & Wilken, 1979). Exchange theory is based upon three elements: ra-tionality, marginal utility, and fairness (McCarville & Copeland, 1994). McCarville and Copeland con-tended that rationality in marketing or sponsorship agreements focuses on the elucidation of all par-ties’ goals, achievement of stated goals, and that past favorable outcomes for participants increase the likelihood of future agreements. Conversely, if a previous agreement has not fulfilled partici-pants’ expectations, the likelihood of any future agreement being finalized is diminished. In exchange Page 54

Enrico Pontelli

One of the main goals of the Semantic Web initiative [3] is to extend the current Web technology to allow for the development of intelligent agents, which can automatically and unambiguously process the information available on millions of web pages. It has been recognized very early in the development of the Semantic Web that rules are essential for the Web3 and for Semantic Web applications—e.g., description of semantic web services, rules interchange for e-business applications. The RuleML initiative is a response to the need of a shared rule markup language using XML markup, which has a precisely defined semantics and efficient implementations. In recent years, a significant amount of work has been devoted to develop knowledge representation languages suitable for the task and a variety of languages for rule markup has been proposed. The initial design [4] included a distinction (in terms of distinct DTDs) between reaction rules and derivation rules. The first type of rules is used for the encoding of event-condition-action (ECA) rules while the second is meant for the encoding of implicational/inference rules. Despite the fact that many different proposals for ECA rules encoding have appeared the work on ECA rules is still very vague. The most recent modularized description of RuleML [6] reports this area (indicated as PR RuleML in that document) as work in progress. The derivation rules component of the RuleML initiative has originated a family of languages.4, Datalog plays the role of a core language, with simplified versions (unary and binary Datalog) developed for combining RuleML with OWL (as in SWRL). Various sublanguages have been created to include features like explicit equality (e.g., fologeq), negation as failure (e.g., naffolog), and Hilog layers (e.g., hohornlog). Various authors [7] have argued that any realistic architecture for the Semantic Web must be based on various independent but interoperable languages, including logic programming languages with and without negation-as-failure. The need for these languages and their interaction have been discussed (e.g., [8, 7]). It is also of

Cudré-Mauroux, Philippe

In the past, the problem of semantic interoperability in information systems was mostly solved by means of centralization, both at a system and at a logical level. This approach has been successful to a certain extent, but offers limited scalability and flexibility. Peer-to-Peer systems as a new brand of system architectures indicate that the principles of decentralization and self-organization might offer new solutions to many problems that scale well to very large numbers of users, or to systems where central authorities do not prevail. Therefore, we suggest a new way of building global agreements, i.e., semantic interoperability, based on decentralized, self-organizing interactions only. In the first part of this thesis, we discuss traditional data integration techniques relying on global schemas, perfect schema mappings and contained query rewritings. We elaborate on the current ecology of the World Wide Web, where autonomous information sources come and go in dynamic and unpredictable ways. In the current environment, data, schemas and schema mappings can all be generated without human intervention and get encoded in syntactic structures with limited expressivity. We argue that traditional top-down integration techniques are inapplicable to that new context and propose a new integration architecture based on decentralized mappings and dynamic self-organization. In the second part of this thesis, we propose a set of principles to foster semantic interoperability in very large scale information systems. We start by introducing new metrics for the schema mappings, based on both syntactic losses (completeness) and semantic mismatch (soundness) to selectively reformulate queries in a decentralized network of heterogeneous parties. We detail analytical methods to evaluate our metrics, and show how to take advantage of those methods to gradually alleviate mapping inconsistencies across the network. We describe a totally decentralized message passing scheme using belief propagation on transitive closures of schema mapping operations to efficiently evaluate the degree of semantic mismatch between pairs of acquainted information systems. Finally, we propose a graph-theoretic analysis of the network of mappings to quantify the quality of the global agreement that can be achieved in that way. The third and last part of this thesis is devoted to the presentation of two systems illustrating the practical applicability of our ideas. The first system we introduce, GridVine, is a Semantic Overlay Network supporting decentralized data integration techniques through pairwise schema mappings and monotonic schema inheritance. GridVine follows the principle of data independence by separating a logical layer, the semantic overlay for managing and mapping data and schemas, from a physical layer consisting of a self-organizing Peer-to-Peer overlay network for efficient routing of messages. The second system, called PicShark, takes advantage of semi-structured metadata to meaningfully share pictures in collaborative settings. PicShark builds on our principles to dynamically create both annotations and mappings, and to gradually minimize information entropy – in terms of missing metadata and schematic heterogeneity – in a self-organizing and decentralized context. Throughout this thesis, we advocate a holistic view on semantics in large-scale information systems: we model semantics as bottom-up and dynamic agreements among heterogeneous parties. We consider both the representation of semantics and the discovery of the interpretation of symbols as the result of a self-organizing process performed by distributed agents whose utility functions depend on the proper interpretation of the symbols. Our view sharply contrasts with previous top-down contributions analyzing data sources in isolation or focusing on global vocabularies and rigid sets of interpretations curated off-line. In a world where digital information is abundant but human attention remains scarce, we believe that autonomous, best-effort processes such as the ones proposed throughout this thesis will play an ever increasing role in complementing traditional top-down integration approaches to handle massive amounts of digitalized and heterogeneous information assets.

Yaling Zhang

This paper proposes a forward-secure undeniable digital signature scheme based on zero-knowledge proof.By combining the undeniable digital signature with the forward-secure digital signature,the new scheme keeps the general property of undeniable digital signature,and has the character of forward-secure,namely,the loss can be reduced to the lowest once the secret key is lost(or stolen).The scheme has some features such as undeniable and unforgeable of the digital signature,and the size of key and signature are short.The idea of zero-knowledge proof is used in key update protocol,which guarantees key update is secure.The scheme is secure under the assumption of standard intractability problems.

Wei Wei

WANG et al.recently proposed two zero-knowledge proof schemes of possessing a RSA digital signature.These schemes give a new method of preventing arbitrary propagation of digital signature.However,the security of the first WANG et al.'s schemes is not as secure as they have claimed.In the random oracle model,a prover without a RSA digital signature could cheat a verifier when the public key is small.

Manoj Prabhakaran, Rui Xue

Zero-knowledge set is a primitive introduced by Micali, Rabin, and Kilian (FOCS 2003) which enables a prover to commit a set to a verifier, without revealing even the size of the set. Later the prover can give zero-knowledge proofs to convince the verifier of membership/nonmembership of elements in/not in the committed set. We present a new primitive called Statistically Hiding Sets (SHS), similar to zero-knowledge sets, but providing an information theoretic hiding guarantee. This is comparable to relaxing zero-knowledge proofs to witness independent proofs. More precisely, we continue to use the simulation paradigm for our definition, but do not require the simulator (nor the distinguisher) to be efficient. We present a new scheme for statistically hiding sets, which does not fit into the “Merkletree/mercurial-commitment” paradigm used for all zero-knowledge set constructions so far. This not only provides some efficiency gains compared to the best possible schemes in that paradigm, but also lets us provide statistical hiding, without the prover having to maintain growing amounts of state with each new proof; this is not known to be possible with the previous approach.