The value of feedback for decentralized detection in large sensor networks

We consider the decentralized binary hypothesis testing problem in networks with feedback, where some or all of the sensors have access to compressed summaries of other sensors' observations. We study certain two-message feedback architectures, in which every sensor sends two messages to a fusion center, with the second message based on full or partial knowledge of the first messages of the other sensors. Under either a Neyman-Pearson or a Bayesian formulation, we show that the asymptotically optimal (in the limit of a large number of sensors) detection performance (as quantified by error exponents) does not benefit from the feedback messages

Error exponents for decentralized detection in feedback architectures

We consider the decentralized Bayesian binary hypothesis testing problem in feedback architectures, in which the fusion center broadcasts information based on the messages of some sensors to some or all sensors in the network. We show that the asymptotically optimal detection performance (as quantified by error exponents) does not benefit from the feedback messages. In addition, we determine the corresponding optimal error exponents.National Science Foundation (U.S.) (Grant ECCS-0701623

An Evaluation of the Accuracy of Online Translation Systems

Until fairly recently, translation among a large variety of natural languages has been difficult and costly. Now, several free, Web-based machine translation (MT) services can provide support, but relatively little research has been conducted on their accuracies. A study of four of these services using German-to-English and Spanish-to-English translations showed that Google Translate appeared to be superior. Further study using this system alone showed that while translations were not always perfect, their understandability was quite high

Studies on Silica-Scaled Chrysophytes from Iowa

References in the literature to the silica-scaled chrysophytes of Iowa are few and, since the advent of the electron microscope, identifications of taxa in this group are no longer considered valid without accompanying electron micrographs. Using scanning electron microscopy for critical identifications, eight taxa genera of the Synuraceae are reported here including the first known report of the genus Paraphysomonas from Iowa. From the other two genera, Mallomonas and Synura, only one of the taxa in this paper, Mallomonas pseudocoronata, has been reported from Iowa previously. Mallomonas acaroides var. striatula, M. tonsurata, M. tonsurata var. alpina, M. teilingii, M. pseudocorcnata, Mallomonas sp., Synura petersenii, and Paraphysomonas imperforata are the taxa reported

Motivations for Online News Usage: An Australian Survey

This paper considers user motivation and acceptance for adoption of online newspapers. The Technology Acceptance Model (TAM) was modified to incorporate several external variables that have been identified as strong influences of technology acceptance: gender, social influences and the level of Internet experience as well as other variables. The model was tested via an online questionnaire where 1592 responses collected. The results provide strong support for social influence and Internet experience and cost in influencing users’ acceptance of an online newspaper. The implications of these findings for theory and practice are discussed

Bayesian Detection in Bounded Height Tree Networks

We study the detection performance of large scale sensor networks, configured as trees with bounded height, in which information is progressively compressed as it moves towards the root of the tree. We show that, under a Bayesian formulation, the error probability decays exponentially fast, and we provide bounds for the error exponent. We then focus on the case where the tree has certain symmetry properties. We derive the form of the optimal exponent within a restricted class of easily implementable strategies, as well as optimal strategies within that class. We also find conditions under which (suitably defined) majority rules are optimal. Finally, we provide evidence that in designing a network it is preferable to keep the branching factor small for nodes other than the neighbors of the leaves

Nanocalorimetric Evidence for Nematic Superconductivity in the Doped Topological Insulator Sr0.1_{0.1}Bi2_{2}Se3_{3}

Spontaneous rotational-symmetry breaking in the superconducting state of doped $\mathrm{Bi}_2\mathrm{Se}_3$ has attracted significant attention as an indicator for topological superconductivity. In this paper, high-resolution calorimetry of the single-crystal $\mathrm{Sr}_{0.1}\mathrm{Bi}_2\mathrm{Se}_3$ provides unequivocal evidence of a two-fold rotational symmetry in the superconducting gap by a \emph{bulk thermodynamic} probe, a fingerprint of nematic superconductivity. The extremely small specific heat anomaly resolved with our high-sensitivity technique is consistent with the material's low carrier concentration proving bulk superconductivity. The large basal-plane anisotropy of $H_{c2}$ is attributed to a nematic phase of a two-component topological gap structure $\vec{\eta} = (\eta_{1}, \eta_{2})$ and caused by a symmetry-breaking energy term $\delta (|\eta_{1}|^{2} - |\eta_{2}|^{2}) T_{c}$. A quantitative analysis of our data excludes more conventional sources of this two-fold anisotropy and provides the first estimate for the symmetry-breaking strength $\delta \approx 0.1$, a value that points to an onset transition of the second order parameter component below 2K