HARDI: A high angular resolution deployable interferometer for space

We describe here a proposed orbiting interferometer covering the UV, visible, and near-IR spectral ranges. With a 6-m baseline and a collecting area equivalent to about a 1.4 m diameter full aperture, this instrument will offer significant improvements in resolution over the Hubble Space Telescope, and complement the new generation of ground-based interferometers with much better limiting magnitude and spectral coverage. On the other hand, it has been designed as a considerably less ambitious project (one launch) than other current proposals. We believe that this concept is feasible given current technological capabilities, yet would serve to prove the concepts necessary for the much larger systems that must eventually be flown. The interferometer is of the Fizeau type. It therefore has a much larger field (for guiding) better UV throughout (only 4 surfaces) than phased arrays. Optimize aperture configurations and ideas for the cophasing and coalignment system are presented. The interferometer would be placed in a geosynchronous or sunsynchronous orbit to minimize thermal and mechanical disturbances and to maximize observing efficiency

An Interview with Jean-François Vernay

The second edition of Jean-François Vernay’s book A Brief Take on the Australian Novel (Adelaide: Wakefield Press) was released in 2016. This incisive history of Australian fiction is remarkable for a relatively young scholar, both for its ambitious scope and its innovative approach, employing structural techniques derived from the world and language of cinema. It is designed to appeal to the general reader seeking to test their views against Vernay’s, to those new to the area of Australian fiction who might use it as a guide to their reading, and to those engaged in academic study. As has often been noted, Jean-François Vernay’s French-Australian parentage and background give him an unusual and distinctive perspective on Australian writing. Jean-François is also the author of Water from the Moon: Illusion and Reality in the Works of Christopher Koch (New York: Cambria Press, 2007), as well as numerous other critical studies. His book The Seduction of Fiction: A Plea for Putting Emotions Back into Literary Interpretation will be released in August 2016 as part of Palgrave Macmillan’s series Studies in Affect Theory and Literary Criticism. He is also a creative writer in his own right, notably of Un doux petit rêveur (2012)

A Review and Update of Public Budgeting in Defense: Leveraging a New Management Model for Government

DRMI Working Paper SeriesThe series is intended to convey the preliminary results of [DRMI] ongoing research. The research described in these papers is preliminary and has not completed the usual review process for Institute publications. We welcome feedback from readers and encourage you to convey your comments and criticisms directly to the authors

POISED: Spotting Twitter Spam Off the Beaten Paths

Cybercriminals have found in online social networks a propitious medium to spread spam and malicious content. Existing techniques for detecting spam include predicting the trustworthiness of accounts and analyzing the content of these messages. However, advanced attackers can still successfully evade these defenses. Online social networks bring people who have personal connections or share common interests to form communities. In this paper, we first show that users within a networked community share some topics of interest. Moreover, content shared on these social network tend to propagate according to the interests of people. Dissemination paths may emerge where some communities post similar messages, based on the interests of those communities. Spam and other malicious content, on the other hand, follow different spreading patterns. In this paper, we follow this insight and present POISED, a system that leverages the differences in propagation between benign and malicious messages on social networks to identify spam and other unwanted content. We test our system on a dataset of 1.3M tweets collected from 64K users, and we show that our approach is effective in detecting malicious messages, reaching 91% precision and 93% recall. We also show that POISED's detection is more comprehensive than previous systems, by comparing it to three state-of-the-art spam detection systems that have been proposed by the research community in the past. POISED significantly outperforms each of these systems. Moreover, through simulations, we show how POISED is effective in the early detection of spam messages and how it is resilient against two well-known adversarial machine learning attacks

PAMPA in the wild:a real-life evaluation of a lightweight ad-hoc broadcasting family

Broadcast is one of the core building blocks of many services deployed on ad-hoc wireless networks, such as Mobile Ad-Hoc Networks (MANETs) or Wireless Sensor Networks (WSNs). Most broadcast protocols are however only ever evaluated using simulations, which have repeatedly been shown to be unreliable, and potentially misleading. In this paper, we seek to go beyond simulations, and consider the particular case of PAMPA, a promising family of wireless broadcast algorithms for ad-hoc and wireless networks. We report on our efforts to further our experimental understanding of PAMPA, and present the first ever characterisation of the PAMPA family on a real deployment. Here it has to deal with real network problems such as node, message and sending failure. Our experiments show that the standard PAMPA algorithm out-performs all other protocols in the family, with a delivery ratio consistently around 75%, and a retransmission ratio as low as 44%, for a failure-free run. We use this opportunity to reflect on our findings and lessons learnt when moving from simulations to actual experimentsab

Healthcare Programmes for Truck Drivers in Sub-Saharan Africa: A Systematic Review and Meta-Analysis.

BACKGROUND: Truck drivers have unique health needs, and by virtue of their continuous travel, experience difficulty in accessing healthcare. Currently, planning for effective care is hindered by lack of knowledge about their health needs and about the impact of on-going programmes on this population's health outcomes. We reviewed healthcare programmes implemented for sub-Saharan African truck drivers, assessed the evaluation methods, and examined impact on health outcomes. METHODS: We searched scientific and institutional databases, and online search engines to include all publications describing a healthcare programme in sub-Saharan Africa where the main clients were truck drivers. We consulted experts and organisations working with mobile populations to identify unpublished reports. Forest plots of impact and outcome indicators with unadjusted risk ratios and 95% confidence intervals were created to map the impact of these programmes. We performed a subgroup analysis by type of indicator using a random-effects model to assess between-study heterogeneity. We conducted a sensitivity analysis to examine both the summary effect estimate chosen (risk difference vs. risk ratio) and model to summarise results (fixed vs. random effects). RESULTS: Thirty-seven publications describing 22 healthcare programmes across 30 countries were included from 5,599 unique records. All programmes had an HIV-prevention focus with only three expanding their services to cover conditions other primary healthcare services. Twelve programmes were evaluated and most evaluations assessed changes in input, output, and outcome indicators. Absence of comparison groups, preventing attribution of the effect observed to the programme and lack of biologically confirmed outcomes were the main limitations. Four programmes estimated a quantitative change in HIV prevalence or reported STI incidence, with mixed results, and one provided anecdotal evidence of changes in AIDS-related mortality and social norms. Most programmes showed positive changes in risk behaviours, knowledge, and attitudes. Our conclusions were robust in sensitivity analyses. CONCLUSION: Diverse healthcare programmes tailored to the needs of truck drivers implemented in 30 sub-Saharan African countries have shown potential benefits. However, information gaps about availability of services and their effects impede further planning and implementation of effective healthcare programmes for truck drivers

Exoplanet Characterization by Proxy: a Transiting 2.15 R_Earth Planet Near the Habitable Zone of the Late K dwarf Kepler-61

We present the validation and characterization of Kepler-61b: a 2.15 R_Earth planet orbiting near the inner edge of the habitable zone of a low-mass star. Our characterization of the host star Kepler-61 is based upon a comparison with the set of spectroscopically similar stars with directly-measured radii and temperatures. We apply a stellar prior drawn from the weighted mean of these properties, in tandem with the Kepler photometry, to infer a planetary radius for Kepler-61b of 2.15+/-0.13 R_Earth and an equilibrium temperature of 273+/-13 K (given its period of 59.87756+/-0.00020 days and assuming a planetary albedo of 0.3). The technique of leveraging the physical properties of nearby "proxy" stars allows for an independent check on stellar characterization via the traditional measurements with stellar spectra and evolutionary models. In this case, such a check had implications for the putative habitability of Kepler-61b: the planet is 10% warmer and larger than inferred from K-band spectral characterization. From the Kepler photometry, we estimate a stellar rotation period of 36 days, which implies a stellar age of >1 Gyr. We summarize the evidence for the planetary nature of the Kepler-61 transit signal, which we conclude is 30,000 times more likely to be due to a planet than a blend scenario. Finally, we discuss possible compositions for Kepler-61b with a comparison to theoretical models as well as to known exoplanets with similar radii and dynamically measured masses.Comment: 23 pages, 12 figures. Accepted for publication in Ap