Video Stream Retrieval of Unseen Queries using Semantic Memory

Retrieval of live, user-broadcast video streams is an under-addressed and increasingly relevant challenge. The on-line nature of the problem requires temporal evaluation and the unforeseeable scope of potential queries motivates an approach which can accommodate arbitrary search queries. To account for the breadth of possible queries, we adopt a no-example approach to query retrieval, which uses a query's semantic relatedness to pre-trained concept classifiers. To adapt to shifting video content, we propose memory pooling and memory welling methods that favor recent information over long past content. We identify two stream retrieval tasks, instantaneous retrieval at any particular time and continuous retrieval over a prolonged duration, and propose means for evaluating them. Three large scale video datasets are adapted to the challenge of stream retrieval. We report results for our search methods on the new stream retrieval tasks, as well as demonstrate their efficacy in a traditional, non-streaming video task.Comment: Presented at BMVC 2016, British Machine Vision Conference, 201

“Repressions Are Necessary; the Newspaper Hype Is Not”: Explaining Terror in Soviet Terms

The article was submitted on 17.02.2020.Ever since Robert Conquest’s pioneering study of Joseph Stalin’s Soviet Union first appeared in 1968, the high point of state-sponsored violence in the 1930s has been commonly referred to as the “Great Terror”. The subsequent adoption of the eponymous title by scholars to describe the broader phenomenon of “state terror” in the Stalinist period is similarly now widespread within the field. This terminology is, however, highly problematic. In the language and ideology of the Communist Party of the Soviet Union (CPSU) terror was consistently portrayed as a threat to, rather than strategy of, the state. It formed part of a tightly controlled terminology of terror, rooted in the Party’s experiences of revolution and civil war, and employed by the regime to marginalize and condemn opponents in official propaganda and private discourse. This study will address this key distinction and illuminate an important element of continuity in the tactics, ideology and self-perception of the CPSU, and its satellite parties within the Communist International, when approaching challenges to their authority (both real and imagined), whether they were of a social, political or even international flavour. Deploying a case study approach, this paper will demonstrate the extent to which “terror” and other related language offered a stable characterisation of the “enemy” throughout the interwar periodВ 1968 г. Роберт Конквест впервые опубликовал новаторское исследование политической ситуации в Советском Союзе в период правления Иосифа Сталина. С этого момента пик государственного насилия 1930-х гг. Стали называть «Большим террором». В последующем термин получил широкое распространение в научных кругах в связи с его использованием для описания более общего феномена государственного террора в сталинский период. Однако это определение представляется весьма проблемным. В языковых практиках и идеологии КПСС понятие «террор» использовали скорее для обозначения опасного для государства явления, чем для описания государственной политики. Все это сформировало, по крайней мере частично, жестко контролируемую терминологию, связанную с террором, берущую начало в том опыте, который партия получила в эпоху революции и Гражданской войны. Терминология террора использовалась режимом для маргинализации и осуждения оппонентов в официальной пропаганде и в частном дискурсе. Настоящее исследование затрагивает ключевую проблему различия в представлениях о направленности террора (от государства или против государства). Особое внимание уделяется связям и преемственности между тактикой, идеологией и самовосприятием КПСС и входившими в Коминтерн партиями-сателлитами в условиях реальных и мнимых социальных, политических и даже международных вызовов их господству. Исследование осуществлено с использованием методов case study с целью показать степень, до которой «террор» и связанные с ним понятия формируют типичные характеристики «врага» в межвоенный период

Testing Luminescence Dating Methods for Small Samples from Very Young Fluvial Deposits

The impetus behind this study is to understand the sedimentological dynamics of very young fluvial systems in the Amazon River catchment and relate these to land use change and modern analogue studies of tidal rhythmites in the geologic record. Initial quartz optically stimulated luminescence (OSL) dating feasibility studies have concentrated on spit and bar deposits in the Rio Tapajós. Many of these features have an appearance of freshly deposited pristine sand, and these observations and information from anecdotal evidence and LandSat imagery suggest an apparent decadal stability. The characteristics of OSL from small (~5 cm) sub-samples from ~65 cm by ~2 cm diameter vertical cores are quite remarkable. Signals from medium-sized aliquots (5 mm diameter) exhibit very high specific luminescence sensitivity, have excellent dose recovery and recycling, essentially independent of preheat, and show minimal heat transfer even at the highest preheats. These characteristics enable measurement of very small signals with reasonable precision and, using modified single-aliquot regenerative-dose (SAR) approaches, equivalent doses as low as ~4 mGy can be obtained. Significant recuperation is observed for samples from two of the study sites and, in these instances, either the acceptance threshold was increased or growth curves were forced through the origin; recuperation is considered most likely to be a measurement artefact given the very small size of natural signals. Dose rates calculated from combined inductively coupled plasma mass spectrometry/inductively coupled plasma optical emission spectrometry (ICP-MS/ICP-OES) and high-resolution gamma spectrometry range from ~0.3 to 0.5 mGya−1 , and OSL ages for features so far investigated range from 13 to 34 years to several 100 years. Sampled sands are rich in quartz and yields of 212–250 µm or 250–310 µm grains indicate high-resolution sampling at 1–2 cm intervals is possible. Despite the use of medium-sized aliquots to ensure the recovery of very dim natural OSL signals, these results demonstrate the potential of OSL for studying very young active fluvial processes in these settings

High energy cosmic-ray interactions with particles from the Sun

Cosmic-ray protons with energies above $10^{16}$ eV passing near the Sun may interact with photons emitted by the Sun and be excited to a $\Delta^+$ resonance. When the $\Delta^+$ decays, it produces pions which further decay to muons and photons which may be detected with terrestrial detectors. A flux of muons, photon pairs (from $\pi^0$ decay), or individual high-energy photons coming from near the Sun would be a rather striking signature, and the flux of these particles is a fairly direct measure of the flux of cosmic-ray nucleons, independent of the cosmic-ray composition. In a solid angle within $15^\circ$ around the Sun the flux of photon pairs is about \SI{1.3e-3}{} particles/(km$^2\cdot$yr), while the flux of muons is about \SI{0.33e-3}{} particles/(km$^2\cdot$yr). This is beyond the reach of current detectors like the Telescope Array, Auger, KASCADE-Grande or IceCube. However, the muon flux might be detectable by next-generation air shower arrays or neutrino detectors such as ARIANNA or ARA. We discuss the experimental prospects in some detail. Other cosmic-ray interactions occuring close to the Sun are also briefly discussed.Comment: 8 pages, 11 figure

Coordination and Sustainability of River Observing Activities in the Arctic

To understand and respond to changes in the world’s northern regions, we need a coordinated system of long-term Arctic observations. River networks naturally integrate across landscapes and link the terrestrial and ocean domains. Changes in river discharge reflect changes in the terrestrial water balance, whereas changes in water chemistry are linked to changes in biogeochemical processes and water flow paths. Sustained measurements of river water discharge and water chemistry are therefore essential components of an Arctic observing network. As we strive to establish and sustain long-term observations in the Arctic, these two measurements must be coupled. Although river discharge and chemistry measurements are already coupled to some extent within national boundaries, this is not done in a consistent and coordinated fashion across the pan-Arctic domain. As a consequence, data quality and availability vary widely among regions. International coordination of river discharge and chemistry measurements in the Arctic would be greatly facilitated by formal commitments to maintain a set of core sites and associated measurements that are mutually agreed upon among pan-Arctic nations. Involvement of the agencies currently operating river discharge gauges around the Arctic and establishment of an overarching coordination entity to implement shared protocols, track data quality, and manage data streams would be essential in this endeavor. Focused studies addressing scale-dependent relationships between watershed characteristics and water chemistry, in-stream processes, and estuarine and coastal dynamics are also needed to support interpretation and application of Arctic river observing data as they relate to land and ocean change

A Robust Numerical Method for Integration of Point-Vortex Trajectories in Two Dimensions

The venerable 2D point-vortex model plays an important role as a simplified version of many disparate physical systems, including superfluids, Bose-Einstein condensates, certain plasma configurations, and inviscid turbulence. This system is also a veritable mathematical playground, touching upon many different disciplines from topology to dynamic systems theory. Point-vortex dynamics are described by a relatively simple system of nonlinear ODEs which can easily be integrated numerically using an appropriate adaptive time stepping method. As the separation between a pair of vortices relative to all other inter-vortex length scales decreases, however, the computational time required diverges. Accuracy is usually the most discouraging casualty when trying to account for such vortex motion, though the varying energy of this ostensibly Hamiltonian system is a potentially more serious problem. We solve these problems by a series of coordinate transformations: We first transform to action-angle coordinates, which, to lowest order, treat the close pair as a single vortex amongst all others with an internal degree of freedom. We next, and most importantly, apply Lie transform perturbation theory to remove the higher-order correction terms in succession. The overall transformation drastically increases the numerical efficiency and ensures that the total energy remains constant to high accuracy.Comment: 21 pages, 4 figure

Trends in dental caries experience of school children in Australia - 1977 to 1993

The document attached has been archived with permission from the Australian Dental Association. An external link to the publisher’s copy is included.Data on the dental health of Australian school children from 1977 to 1985 have previously been reported. Significant features included a secular decline in caries experience as defined by the number of decayed, missing and filled teeth in both the deciduous dentition (dmft index) and permanent dentition (DMFT index), and a change in the distribution of caries experience within the child population in Australia, indicated by increasingly smaller percentages of children accounting for greater proportions of total disease experience. The aim of the present paper was to extend the annual reporting on caries experience in Australia up to and including 1993, and to document the change in the distribution of caries within the child population since 1977. In addition, the data are compared with dental targets for children for the year 2000 in Australia and internationally. Caries data were obtained for the years 1977-1993 for children who were patients at School Dental Services in each State and Territory of Australia. Caries experience was recorded by uncalibrated dentists and dental therapists during routine dental examinations. From 1977-89 data were weighted by State and Territory estimated resident populations. From 1989, the data were stratified according to age, year, and State, and weighted to reflect proportions in the national estimated resident population for each State/age stratum. Between 1977 and 1993 there has been a decline in caries experience for 6 year old children from a dift++ of 3.13 to a dmft of 1.90, and an increase in the per cent with dmft = 0 from 33.1 per cent to 53.2 per cent with dmft = 0 in 1993. Over the same time period the DMFT for 12 year olds reduced from 4.79 to 1.10 and the per cent while DMFT = 0 increased from 10.5 per cent to 53.1 per cent. Projection of the decline in DMFT indicates the dental health target for 12 year old children of DMFT = 1.0 by the year 2000 should have been achieved by the end of 1995.M.J. Davies, A.J. Spencer, G.D. Slad