19,370 research outputs found

    ATM optical contamination study - Reaction control system rocket engine space plume flow fields Interim report

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    Apollo telescopic experiment contamination by space vehicle exhaust product

    Fluctuations of Entropy Production in Partially Masked Electric Circuits: Theoretical Analysis

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    In this work we perform theoretical analysis about a coupled RC circuit with constant driven currents. Starting from stochastic differential equations, where voltages are subject to thermal noises, we derive time-correlation functions, steady-state distributions and transition probabilities of the system. The validity of the fluctuation theorem (FT) is examined for scenarios with complete and incomplete descriptions.Comment: 4 pages, 1 figur

    The Sender-Excited Secret Key Agreement Model: Capacity, Reliability and Secrecy Exponents

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    We consider the secret key generation problem when sources are randomly excited by the sender and there is a noiseless public discussion channel. Our setting is thus similar to recent works on channels with action-dependent states where the channel state may be influenced by some of the parties involved. We derive single-letter expressions for the secret key capacity through a type of source emulation analysis. We also derive lower bounds on the achievable reliability and secrecy exponents, i.e., the exponential rates of decay of the probability of decoding error and of the information leakage. These exponents allow us to determine a set of strongly-achievable secret key rates. For degraded eavesdroppers the maximum strongly-achievable rate equals the secret key capacity; our exponents can also be specialized to previously known results. In deriving our strong achievability results we introduce a coding scheme that combines wiretap coding (to excite the channel) and key extraction (to distill keys from residual randomness). The secret key capacity is naturally seen to be a combination of both source- and channel-type randomness. Through examples we illustrate a fundamental interplay between the portion of the secret key rate due to each type of randomness. We also illustrate inherent tradeoffs between the achievable reliability and secrecy exponents. Our new scheme also naturally accommodates rate limits on the public discussion. We show that under rate constraints we are able to achieve larger rates than those that can be attained through a pure source emulation strategy.Comment: 18 pages, 8 figures; Submitted to the IEEE Transactions on Information Theory; Revised in Oct 201

    Renewing the Good Intentions of Foster Care: Enforcement of the Adoption Assistance and Child Welfare Act of 1980 and the Substantive Due Process Right to Safety

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    Foster care. There are probably no two words in the English language that convey more of a sense of good intentions gone bad. Children enter foster care when their own parents fail them. Then they begin a state-sponsored journey through an over- land railroad of foster homes, some run by adults who truly want to help, and others run by scoundrels.\u27 The purpose of foster care is to provide a temporary safe haven for children whose parents are unable to care for them. Unfortunately, however, the foster care system frequently fails to provide children with stable, secure care, and fails to meet their medical, psychological, and emotional needs. Many children spend the better part of their child- hoods in foster homes, often suffering mental, emotional, and physical abuse at the hands of their state-appointed foster parents. Stories of neglected, battered children and horrible living conditions pervade the case law. Deteriorating family relationships and systemic flaws within the child welfare system are to blame for foster family abuse and program abuse. Among the interrelated problems merging into the foster crisis are an increased number of foster children, weakened family relation- ships, deteriorating social conditions, overextended and inefficiently managed child welfare agencies, and poor training of case workers and prospective foster parents. These factors have resulted in an ineffective bureaucracy that has lost sight of its purpose-safe temporary care for children in search of a permanent home
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