Quarterly literature review of the remote sensing of natural resources

The Technology Application Center reviewed abstracted literature sources, and selected document data and data gathering techniques which were performed or obtained remotely from space, aircraft or groundbased stations. All of the documentation was related to remote sensing sensors or the remote sensing of the natural resources. Sensors were primarily those operating within the 10 to the minus 8 power to 1 meter wavelength band. Included are NASA Tech Briefs, ARAC Industrial Applications Reports, U.S. Navy Technical Reports, U.S. Patent reports, and other technical articles and reports

Literature review of the remote sensing of natural resources

Abstracts of 596 documents related to remote sensors or the remote sensing of natural resources by satellite, aircraft, or ground-based stations are presented. Topics covered include general theory, geology and hydrology, agriculture and forestry, marine sciences, urban land use, and instrumentation. Recent documents not yet cited in any of the seven information sources used for the compilation are summarized. An author/key word index is provided

Instrumental oscillations in RHESSI count rates during solar flares

Aims: We seek to illustrate the analysis problems posed by RHESSI spacecraft motion by studying persistent instrumental oscillations found in the lightcurves measured by RHESSI's X-ray detectors in the 6-12 keV and 12-25 keV energy range during the decay phase of the flares of 2004 November 4 and 6. Methods: The various motions of the RHESSI spacecraft which may contribute to the manifestation of oscillations are studied. The response of each detector in turn is also investigated. Results: We find that on 2004 November 6 the observed oscillations correspond to the nutation period of the RHESSI instrument. These oscillations are also of greatest amplitude for detector 5, while in the lightcurves of many other detectors the oscillations are small or undetectable. We also find that the variation in detector pointing is much larger during this flare than the counterexample of 2004 November 4. Conclusions: Sufficiently large nutation motions of the RHESSI spacecraft lead to clearly observable oscillations in count rates, posing a significant hazard for data analysis. This issue is particularly problematic for detector 5 due to its design characteristics. Dynamic correction of the RHESSI counts, accounting for the livetime, data gaps, and the transmission of the bi-grid collimator of each detector, is required to overcome this issue. These corrections should be applied to all future oscillation studies.Comment: 8 pages, 10 figure

Detecting Classical Phase Transitions with Renyi Mutual Information

By developing a method to represent the Renyi entropies via a replica-trick on classical statistical mechanical systems, we introduce a procedure to calculate the Renyi Mutual Information in any Monte Carlo simulation. Through simulations on several classical models, we demonstrate that the Renyi Mutual Information can detect finite-temperature critical points, and even identify their universality class, without knowledge of an order parameter or other thermodynamic estimators. Remarkably, in addition to critical points mediated by symmetry breaking, the Renyi Mutual Information is able to detect topological vortex-unbinding transitions, as we explicitly demonstrate on simulations of the XY model.Comment: 5 pages, 4 figure

Wideband digital phase comparator for high current shunts

A wideband phase comparator for precise measurements of phase difference of high current shunts has been developed at INRIM. The two-input digital phase detector is realized with a precision wideband digitizer connected through a pair of symmetric active guarded transformers to the outputs of the shunts under comparison. Data are first acquired asynchronously, and then transferred from on-board memory to host memory. Because of the large amount of data collected the filtering process and the analysis algorithms are performed outside the acquisition routine. Most of the systematic errors can be compensated by a proper inversion procedure. The system is suitable for comparing shunts in a wide range of currents, from several hundred of milliampere up to 100 A, and frequencies ranging between 500 Hz and 100 kHz. Expanded uncertainty (k=2) less than 0.05 mrad, for frequency up to 100 kHz, is obtained in the measurement of the phase difference of a group of 10 A shunts, provided by some European NMIs, using a digitizer with sampling frequency up to 1 MHz. An enhanced version of the phase comparator employs a new digital phase detector with higher sampling frequency and vertical resolution. This permits to decrease the contribution to the uncertainty budget of the phase detector of a factor two from 20 kHz to 100 kHz. Theories and experiments show that the phase difference between two high precision wideband digitizers, coupled as phase detector, depends on multiple factors derived from both analog and digital imprint of each sampling system.Comment: 20 pages, 9 figure

Alkan, the 'orchestral' piano and Concerto for Piano Solo (Homage to Alkan)

This article explores the idea of orchestral imitation or evocation on the piano. Long an aspect of piano writing and performance, the mechanisms by which such suggestive effects are realised in composition, performance and reception are somewhat under-addressed in the literature, especially the academic literature. The article takes an approach which is partly historical, but also focussed on contemporary practice: starting from examples in Mozart and Alkan and Brendel's (1976) writing on Liszt, I finish with a short discussion of my own Concerto for Piano Solo (Homage to Alkan), published in 2015 and released on CD in 2017

‘Dumped modernism’? The interplay of musical construction and spiritual affect in John Tavener and his To A Child Dancing In The Wind

Since the 1990s, discourses around Tavener’s music – not least those promulgated by Sir John himself – have centred on its perceived spiritual qualities. These are linked explicitly with his conversion to Russian Orthodoxy in 1977, and relate the music wholeheartedly to traditional contexts, in contrast with the post-enlightenment Western view of musical expression (with which Tavener’s earlier compositions implicitly concur). As Geoffrey Haydon wrote in 1995, ‘Once he dumped modernism, his music came to inhabit a world made up largely of traditional models’. This view has become almost axiomatic. But did Tavener really ‘dump’ modernism? And was his pre-conversion music exclusively concerned with self-expressive innovation? This chapter explores how techniques associated with musical modernism form structural foundations in pieces which exhibit the contemplative idiom (sometimes labelled spiritual minimalism) for which the composer is renowned. With passing reference to Fall and Resurrection (1997) and The Lamb (1982), it centres on a close analytical reading of the Yeats chamber song-cycle To A Child Dancing In The Wind (1983). In some ways a transitional work, this piece facilitates a holistic understanding of Tavener’s achievement. While its potential for impacting spiritually on listeners is clearly present, it is shown to exemplify particularly well the composer’s distinctive postmodern intellectual craftsmanship. Spiritual affect is one mode of interpreting this and other Tavener pieces, which can be seen to possess a greater interpretive ambiguity and ‘inner life’ of musical construction than he – along with other composers of ‘spiritual minimalism’ – is sometimes given credit for (eg Fisk 1994). Through its ultimately enriching dichotomy of materials and technique, To a Child Dancing in the Wind could even be seen to reconcile two major strands of post-WWII compositional thought (often seen as antithetical): (post-)serialism and minimalism