A comparison of three approaches for determining scalar illuminance from cubic illuminance data

A method for calculating scalar illuminance using cubic illuminance values in a light field has been proposed in the literature. This enables exact measurement of the illuminance vector direction and magnitude by a fixed device, as well as providing a useful basis for calculation. However, the method yields an inexact estimate of the scalar illuminance which in some cases may lead to errors. Two alternative approaches using the concept of mean spherical semi-cubic and cubic illuminances are proposed in this paper, to determine which of these approaches yields the highest accuracy, and to observe the effect of source orientation in various multiple point source configurations. Three types of test are introduced: the first involves two, three, and four identical point sources, separated by a varying angle θ; the second involves four identical point sources arranged symmetrically at varying azimuth angle ψ and incident angle α; the third involves 10,000 combinations of up to six point sources with random luminous intensities and in random positions. Comparisons between the three approaches show that the approach using mean spherical semi-cubic illuminances yields the least amount of error and thus the highest accuracy for scalar illuminance and vector/scalar illuminance ratio in the first and second test. In the third test, this approach also yields the highest accuracy, even though it tends to underestimate the scalar illuminance in scenes with more sources.

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Quantification of Biological Resistance: Introducing a Unifying Unit and Scale of Resistance

10.31219/osf.io/s7fm8 ◽

2018 ◽

Author(s):

Rudolf Fullybright

Keyword(s):

Drug Resistance ◽

Living Organism ◽

Pathogen Resistance ◽

Absolute Quantification ◽

Biological Resistance ◽

The Third ◽

Exact Measurement ◽

Unit Function ◽

Third Law ◽

Accurate Quantification

Accurate quantification of biological resistance has been impossible so far. Among the various forms of biological resistance which exist in nature, pathogen resistance to drugs is a familiar one. However, as in the case of other forms of resistance, accurately quantifying drug resistance in pathogens has been impossible up to now. Here, we introduce a mathematically-defined and uniform procedure for the absolute quantification of biological resistance deployed by any living organism in the biological realm, including and beyond drug resistance in medicine. The scheme introduced makes possible the exact measurement or computation of the extent to which resistance is deployed by any living organism regardless of kingdom and regardless of the mechanism of resistance involved. Furthermore, the Second Law of Resistance indicating that resistance has the potential to increase to infinite levels, and the Third Law of Resistance indicating that resistance comes to an end once interaction stops, the resistance unit function introduced here is fully compatible with both the Second and Third Laws of Resistance.

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A Hologram Computer-Aided Design Tool Extends the Function for Designing and Analyzing Holographic Optical Elements Illuminated by Multiple Point-Sources

Optical Review ◽

10.1007/s10043-003-0275-5 ◽

2003 ◽

Vol 10 (4) ◽

pp. 275-282 ◽

Cited By ~ 2

Author(s):

Yukio Matsuura ◽

Yasuhiro Awatsuji ◽

Tohru Shimizu ◽

Toshihiro Kubota

Keyword(s):

Computer Aided Design ◽

Design Tool ◽

Point Sources ◽

Multiple Point ◽

Optical Elements ◽

Holographic Optical Elements ◽

Computer Aided ◽

Aided Design

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On the point-source approximation of earthquake dynamics

Annals of Geophysics ◽

10.4401/ag-6479 ◽

2014 ◽

Vol 57 (3) ◽

Author(s):

Andrea Bizzarri

Keyword(s):

Point Source ◽

Seismic Waves ◽

Single Point ◽

Seismic Source ◽

Transition Process ◽

Point Sources ◽

Multiple Point ◽

Earthquake Dynamics ◽

Planar Fault ◽

Source Models

The focus on the present study is on the point-source approximation of a seismic source. First, we compare the synthetic motions on the free surface resulting from different analytical evolutions of the seismic source (the Gabor signal (G), the Bouchon ramp (B), the Cotton and Campillo ramp (CC), the Yoffe function (Y) and the Liu and Archuleta function (LA)). Our numerical experiments indicate that the CC and the Y functions produce synthetics with larger oscillations and correspondingly they have a higher frequency content. Moreover, the CC and the Y functions tend to produce higher peaks in the ground velocity (roughly of a factor of two). We have also found that the falloff at high frequencies is quite different: it roughly follows ω−2 in the case of G and LA functions, it decays more faster than ω−2 for the B function, while it is slow than ω−1 for both the CC and the Y solutions. Then we perform a comparison of seismic waves resulting from 3-D extended ruptures (both supershear and subshear) obeying to different governing laws against those from a single point-source having the same features. It is shown that the point-source models tend to overestimate the ground motions and that they completely miss the Mach fronts emerging from the supershear transition process. When we compare the extended fault solutions against a multiple point-sources model the agreement becomes more significant, although relevant discrepancies still persist. Our results confirm that, and more importantly quantify how, the point-source approximation is unable to adequately describe the radiation emitted during a real world earthquake, even in the most idealized case of planar fault with homogeneous properties and embedded in a homogeneous, perfectly elastic medium.

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Super-resolution imaging of negative-refractive graded-index photonic crystal flat lens

Materials Research Express ◽

10.1088/2053-1591/ac4731 ◽

2021 ◽

Author(s):

Binming Liang ◽

Xiao Huang ◽

Jihong Zheng

Keyword(s):

Photonic Crystal ◽

Imaging System ◽

Super Resolution ◽

Point Sources ◽

Image Resolution ◽

Multiple Point ◽

Single Image ◽

Graded Index ◽

Resolution Imaging ◽

Flat Lens

Abstract Photonic crystal (PC) not only breaks through the diffraction limit of traditional lenses but also can realize super-resolution imaging. Improving the resolution is the key task of PC imaging. The main work of this paper is to use a graded-index Photonic crystal (GPC) flat lens to improve the image resolution. An air-hole type two-dimensional (2D) GPC structure based on silicon medium is proposed in this paper. Numerical simulations through RSoft reveal that when the medium in the imaging area is air, the full width at half maximum (FWHM) value of a single image reaches 0.362λ. According to the Rayleigh criterion, the images of two point sources 0.57λ apart can also be distinguished. In the imaging system composed of cedar oil and GPC flat lens, the FWHM value of a single image reaches 0.34λ. In addition, the images of multiple point sources 0.49λ apart can still be distinguished.

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Legibility of Light Signals Composed of Multiple Point Sources

JOURNAL OF THE ILLUMINATING ENGINEERING INSTITUTE OF JAPAN ◽

10.2150/jieij1980.79.2_66 ◽

1995 ◽

Vol 79 (2) ◽

pp. 66-70

Author(s):

Takashi Irikura ◽

Tetsuo Taniguchi ◽

Yoshiro Aoki

Keyword(s):

Point Sources ◽

Multiple Point ◽

Light Signals

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2. IR as an Academic Subject

Introduction to International Relations ◽

10.1093/hepl/9780198803577.003.0002 ◽

2018 ◽

pp. 33-66

Author(s):

Robert Jackson ◽

Georg Sørensen ◽

Jørgen Møller

Keyword(s):

International Political Economy ◽

First World War ◽

Good Theory ◽

World War ◽

The Third ◽

Academic Subject ◽

The First World War ◽

Alternative Approaches ◽

Traditional Approaches ◽

First World

This chapter examines how thinking about international relations (IR) has evolved since IR became an academic subject around the time of the First World War. The focus is on four established IR traditions: realism, liberalism, International Society, and International Political Economy (IPE). The chapter first considers three major debates that have arisen since IR became an academic subject at the end of the First World War: the first was between utopian liberalism and realism; the second between traditional approaches and behaviouralism; the third between neorealism/neoliberalism and neo-Marxism. There is an emerging fourth debate, that between established traditions and post-positivist alternatives. The chapter concludes with an analysis of alternative approaches that challenge the established traditions of IR, and with a discussion about criteria for good theory in IR.

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2. IR as an Academic Subject

Introduction to International Relations ◽

10.1093/hepl/9780198707554.003.0002 ◽

2015 ◽

Author(s):

Robert Jackson ◽

Georg Sørensen

Keyword(s):

Political Economy ◽

International Political Economy ◽

First World War ◽

World War ◽

The Third ◽

Academic Subject ◽

The First World War ◽

Alternative Approaches ◽

Traditional Approaches ◽

First World

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Full reciprocity-gap waveform inversion enabling sparse-source acquisition

Geophysics ◽

10.1190/geo2019-0527.1 ◽

2020 ◽

Vol 85 (6) ◽

pp. R461-R476 ◽

Cited By ~ 1

Author(s):

Florian Faucher ◽

Giovanni Alessandrini ◽

Hélène Barucq ◽

Maarten V. de Hoop ◽

Romina Gaburro ◽

...

Keyword(s):

Least Squares ◽

Waveform Inversion ◽

Point Sources ◽

Seismic Exploration ◽

Multiple Point ◽

Normal Velocity ◽

Reconstruction Procedure ◽

Dual Sensor ◽

Marine Seismic ◽

Propagation Of Waves

The quantitative reconstruction of subsurface earth properties from the propagation of waves follows an iterative minimization of a misfit functional. In marine seismic exploration, the observed data usually consist of measurements of the pressure field, but dual-sensor devices also provide the normal velocity. Consequently, a reciprocity-based misfit functional is specifically designed, and it defines the full reciprocity-gap waveform inversion (FRgWI) method. This misfit functional provides additional features compared to the more traditional least-squares approaches, in particular, in that the observational and computational acquisitions can be different. Therefore, the positions and wavelets of the sources from which the measurements are acquired are not needed in the reconstruction procedure and, in fact, the numerical acquisition (for the simulations) can be chosen arbitrarily. Based on 3D experiments, FRgWI is shown to behave better than full-waveform inversion in the same context. It allows for arbitrary numerical acquisitions in two ways: when few measurements are given, a dense numerical acquisition (compared to the observational one) can be used to compensate. However, with a dense observational acquisition, a sparse computational one is shown to be sufficient, for instance, with multiple-point sources, hence reducing the numerical cost. FRgWI displays accurate reconstructions in both situations and appears more robust with respect to crosstalk than least-squares shot stacking.

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