169 research outputs found

    Inventory of Karst Springs of Fayette County, Kentucky

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    The purpose of this publication is to document karst springs in Fayette County and provide a resource to help the county\u27s citizens avoid the geologic hazards associated with building near springs during future urban development. It may be used as an aid in locating potential groundwater discharge points in case of hazardous material spills, and to provide a foundation for future studies of the hydrogeology and karst geology of the Inner Bluegrass Region. It is also a basic historical record of the springs of Fayette County. Although over 350 springs are reported here, this inventory is not exhaustive. At the time of publication, about one-third of Fayette County had not yet been systematically inventoried. Fortunately, many springs in the unvisited areas were already known and recorded in the Kentucky Geological Survey (KGS) database and are included in this publication. The spring locations shown are mostly those discharging from karst conduits, but also included are a significant number of soil seeps or wet-weather springs (epikarstic), and some springs apparently discharging from fractures created by faults. The springs vary in size from seasonal seeps to perennial springs with base flows approaching 0.5 cubic foot per second. As the rapid pace of urban development continues in Fayette County, some natural springs reported here will become buried, and the records used to compile this publication will be an important resource in the future for separating natural from man-made groundwater discharge points

    Biometrics based privacy-preserving authentication and mobile template protection

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    Smart mobile devices are playing a more and more important role in our daily life. Cancelable biometrics is a promising mechanism to provide authentication to mobile devices and protect biometric templates by applying a noninvertible transformation to raw biometric data. However, the negative effect of nonlinear distortion will usually degrade the matching performance significantly, which is a nontrivial factor when designing a cancelable template. Moreover, the attacks via record multiplicity (ARM) present a threat to the existing cancelable biometrics, which is still a challenging open issue. To address these problems, in this paper, we propose a new cancelable fingerprint template which can not only mitigate the negative effect of nonlinear distortion by combining multiple feature sets, but also defeat the ARM attack through a proposed feature decorrelation algorithm. Our work is a new contribution to the design of cancelable biometrics with a concrete method against the ARM attack. Experimental results on public databases and security analysis show the validity of the proposed cancelable template

    Lever: Breaking the Shackles of Scalable On-chain Validation

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    Blockchain brings dawn to decentralized applications which coordinate correct computations without a prior trust. However, existing scalable on-chain frameworks are incompetent in dealing with intensive validation. On the one hand, duplicated execution pattern leads to limited throughput and unacceptable expenses. On the other hand, there lack fair and secure incentive mechanisms allocating rewards according to the actual workload of validators, thus deriving bad dilemmas among rational participants and inducing effective attacks from shrewd adversaries. While most solutions rely on off-chain patterns to sidestep the shackles, it further introduces unexpected issues in applicability, fairness and brittle dependency on interactive cooperation. The intrinsic bottleneck of backbone has never been drastically broken. This work presents Lever, the first scalable on-chain framework which supports intensive validation, meanwhile achieves validity, incentive compatibility and cost-efficiency tolerance of f<n/4 Byzantine participants. Lever firstly integrates the evaluation of complexity into the correctness of transaction, thoroughly decoupling intensive validation from regular Byzantine consensus. Significant scalability is then achieved by launching few rounds of novel validation-challenge game between potential adversaries and rational stakeholders; compelling incentive mechanism effectively transfers deposits of adversary to specialized rewards for honest validators, therefore allows the user to lever sufficient endorsement for verification with minimum cost. Combined with game-theoretic insights, a backstop protocol is designed to ensure finality and validity of the framework, breaking through the famous Verifier’s Dilemma. Finally, we streamline Lever under the efficient architecture of sharding, which jointly shows robust to conceivable attacks on validation and performs outstanding ability to purify Byzantine participants. Experimental results show that Lever vastly improves the throughput and reduces expenses of intensive validation with slight compromise in latency

    Robust distributed privacy-preserving secure aggregation in vehicular communication

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    Vehicular ad hoc networks (VANETs), formed by computers embedded in vehicles and the traffic infrastructure, are expected to develop in the near future to improve traffic safety and efficiency. To this end, VANETs should be designed to be resistant against various abuses and attacks. In this paper, we first review the existing proposals to provide security, privacy, and data aggregation in vehicle-to-vehicle communication. We then address the fundamental issue of achieving these conflicting properties in a unified solution, having observed that separate efforts cannot fulfill the VANET design objectives. A set of new mechanisms are suggested for efficiently managing identities and securely compressing cryptographic witnesses, which are among the major obstacles to the deployment of strong security mechanisms in VANETs. Finally, we employ the standard threshold cryptographic technology to improve the basic protocol with robustness
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