19,636 research outputs found
Ehrhart Series of Polytopes Related to Symmetric Doubly-Stochastic Matrices
In Ehrhart theory, the -vector of a rational polytope often provide
insights into properties of the polytope that may be otherwise obscured. As an
example, the Birkhoff polytope, also known as the polytope of real
doubly-stochastic matrices, has a unimodal -vector, but when even small
modifications are made to the polytope, the same property can be very difficult
to prove. In this paper, we examine the -vectors of a class of polytopes
containing real doubly-stochastic symmetric matrices.Comment: 11 pages; this revision removes an erroneous proposition from earlier
versions and expands on the implication
Preserving Electronically Encoded Evidence
Seeking to preserve electronically encoded evidence implies that an incident or event has occurred requiring fact extrapolation for presentation, as proof of an irregularity or illegal act. Whether target data are in transit or at rest, it is critical that measures be in place to prevent the sought information from being destroyed, corrupted or becoming unavailable for forensic investigation
The Affects of acid mine drainage on the water quality, and benthic macroinvertebrate and fish population in streams in Maryland
The purpose of this study was to measure and evaluate relationships between populations of benthic macroinvertebrates and fish, as well as variations in water quality in streams affected by acid Mine drainage. (PDF contains 21 pages
Coded 16-CPFSK for downlink applications
A bandwidth-efficient constant-envelope Proof-of-Concept (POC) modem is described. The modem was developed on an Advanced Modulation Techniques Development contract for the NASA/Lewis Research Center. The POC modem employs 16-ary Continuous Phase Frequency Shift Keying (16-CPFSK) modulation. The 16 frequencies are spaced every 1/16th baud rate which produces a compact spectrum allowing 2 bits/sec/Hz operation. The modem is designed for 200 mb/s Time Division Multiple Access (TDMA) application with 100 MHz adjacent channel spacing. Overall rate 3.4 convolutional coding is incorporated. The demodulator differs significantly from typical quadrature phase detector approaches in that phase is coherently measured by processing the baseband output of a frequency discriminator. Baud rate phase samples for the baseband processor are subsequently decoded to yield the original data stream. The method of encoding onto the 16-ary symbol-ending phase nodes, together with convolutional coding gain, results in near Quadrature Phase Shift Keying (QPSK) theoretical performance. The modulated signal is of constant envelope; thus the power amplifier can be saturated for peak performance. The spectrum is inherently bandlimited and requires no RF filter for sidelobe containment. Two novel theoretical techniques are used in this 16-CPFSK modem: (1) coherent phase measurements are obtained by processing an FM discriminator baseband output; and (2) modulation is accomplished via a closed-loop-linearized voltage controlled oscillator (VCO)
Creating cultural change @ campus kindergarten: The sustainable planet project
This article highlights how the Campus Kindergarten community has confronted the challenge of sustainability. It has done this by creating a ‘learning organisation’ where a culture of sustainability is continuously recreated by taking advantage of, rather than resisting, the natural power of complexity. This centre is a model of quality early childhood education for sustainability
Raising standards in performance
Over the past few years, instrumental performance has been subject to considerable
research in this journal and elsewhere. A great deal of this research has concentrated on
the practice strategies and individual lessons, which most students undertake in preparing
as performers. Little has been done on raising standards of performance on a larger scale
within the context of a large music department. This article describes the outcomes of a
two-year programme undertaken with undergraduates at Barnsley College. It looks
speci®cally at the scope for curriculum changes over that period and the way the various
individual aspects of performance lessons are brought together through a weekly class
which focuses on the demands of a public performance and the strategies required to
prepare for that event
Modeling of coalescence, agglomeration, and phase segregation in microgravity processing of bimetallic composite materials
The overall objective of this research is to develop models to predict drop-size-distribution evolutions due to droplet collisions and coalescence during processing within the miscibility gap of bimetallic liquid-phase-miscibility-gap materials. The individual and collective action of gravitational and nongravitational mechanisms on the relative motion and coalescence of drops are considered
Situating care in mainstream health economics: an ethical dilemma?
Standard health economics concentrates on the provision of care by medical professionals. Yet ‘care’ receives scant analysis; it is portrayed as a spillover effect or externality in the form of interdependent utility functions. In this context care can only be conceived as either acts of altruism or as social capital. Both conceptions are subject to considerable problems stemming from mainstream health economics’ reliance on a reductionist social model built around instrumental rationality and consequentialism. Subsequently, this implies a disregard for moral rules and duties and the compassionate aspects of behaviour. Care as an externality is a second-order concern relative to self-interested utility maximization, and is therefore crowded out by the parameters of the standard model. We outline an alternative relational approach to conceptualising care based on the social embeddedness of the individual that emphasises the ethical properties of care. The deontological dimension of care suggests that standard health economics is likely to undervalue the importance of care and caring in medicine
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