scholarly journals Graphical Optimization of Spectral Shift Reconstructions for Optical Backscatter Reflectometry

Sensors ◽  
2021 ◽  
Vol 21 (18) ◽  
pp. 6154
Author(s):  
Daniel C. Sweeney ◽  
Dennis M. Sweeney ◽  
Christian M. Petrie
Keyword(s):  
Adaptive Algorithm ◽  
Spanning Tree ◽  
Mechanical Strain ◽  
Adaptive Algorithms ◽  
Spectral Shift ◽  
Reference Measurement ◽  
Interferometric Technique ◽  
Quality Metric ◽  
Spectral Shifts ◽  
Maximum Spanning Tree

Optical backscatter reflectometry (OBR) is an interferometric technique that can be used to measure local changes in temperature and mechanical strain based on spectral analyses of backscattered light from a singlemode optical fiber. The technique uses Fourier analyses to resolve spectra resulting from reflections occurring over a discrete region along the fiber. These spectra are cross-correlated with reference spectra to calculate the relative spectral shifts between measurements. The maximum of the cross-correlated spectra—termed quality—is a metric that quantifies the degree of correlation between the two measurements. Recently, this quality metric was incorporated into an adaptive algorithm to (1) selectively vary the reference measurement until the quality exceeds a predefined threshold and (2) calculate incremental spectral shifts that can be summed to determine the spectral shift relative to the initial reference. Using a graphical (network) framework, this effort demonstrated the optimal reconstruction of distributed OBR measurements for all sensing locations using a maximum spanning tree (MST). By allowing the reference to vary as a function of both time and sensing location, the MST and other adaptive algorithms could resolve spectral shifts at some locations, even if others can no longer be resolved.

scholarly journals Penerapan Bayesian Network dalam Memodelkan Kondisi Ekonomi Hijau Indonesia di Era Pandemi Berdasarkan Big Data

2021 ◽  
Vol 2021 (1) ◽  
pp. 1054-1064
Author(s):  
Salwa Rizqina Putri ◽  
Thosan Girisona Suganda ◽  
Setia Pramana
Keyword(s):  
Big Data ◽  
Bayesian Network ◽  
Data Model ◽  
Spanning Tree ◽  
Cross Validation ◽  
Parameter Learning ◽  
Maximum Spanning Tree

Untuk mendukung pertumbuhan ekonomi hijau Indonesia, diperlukan analisis lebih lanjut terkait aktivitas ekonomi di masa pandemi dan keterkaitannya dengan kondisi lingkungan. Penelitian ini bertujuan untuk menerapkan pendekatan Bayesian Network dalam memodelkan kondisi ekonomi hijau Indonesia di masa pandemi berdasarkan variabel-variabel yang disinyalir dapat berpengaruh seperti aktivitas ekonomi, kualitas udara, tingkat mobilitas penduduk, dan kasus positif COVID-19 yang diperoleh melalui big data. Model Bayesian Network yang dikonstruksi secara manual dengan algoritma Maximum Spanning Tree dipilih sebagai model terbaik dengan rata-rata akurasi 5-cross validation dalam memprediksi empat kelas PDRB sebesar 0,83. Model terbaik yang dipilih menunjukkan bahwa kondisi ekonomi Indonesia di era pandemi secara langsung dipengaruhi oleh intensitas cahaya malam (NTL) yang menunjukkan aktivitas ekonomi, kualitas udara (AQI), dan kasus positif COVID-19. Analisis parameter learning menunjukkan bahwa pertumbuhan ekonomi provinsi-provinsi Indonesia masih cenderung belum sejalan dengan terpeliharanya kualitas udara sehingga usaha untuk mencapai kondisi ekonomi hijau masih harus ditingkatkan.

Modification of the porphyrin chromophore by ring fusion: identifying trends due to annelation of the porphyrin nucleus

2001 ◽  
Vol 05 (03) ◽  
pp. 267-288 ◽  
Author(s):  
TIMOTHY D. LASH
Keyword(s):  
Soret Band ◽  
Spectral Shift ◽  
Aromatic Rings ◽  
Ring Fusion ◽  
Spectral Shifts ◽  
Hyper Spectral ◽  
Two Factors ◽  
Porphyrin Analogues ◽  
Soret Absorption ◽  
Soret Region

The effects exerted by fused aromatic rings on the UV-vis spectra of porphyrins are surveyed. Modified porphyrin chromophores with fused benzene, 1,2-naphthalene, 9,10-phenanthrene or phenanthroline rings are surprisingly little affected even when a maximum number of ring fusions are incorporated. Linearly annealed naphtho- or anthraporphyrins show large red shifts to the Q bands but the Soret absorptions are weakened and undergo only minor bathochromic shifts. Fluoranthoporphyrins give multiple bands in the Soret region, but the Q band region is virtually unaffected by this tetracyclic ring system. On the other hand, metal chelates of fluoranthoporphyrins show surprisingly strong bands near 600 nm. Benzothiadiazole rings split and weaken the Soret band, but the Q bands region is unexceptional. However, metal coordination again produces relatively intense bands near 600 nm. The most significant results were obtained for porphyrins with fused acenaphthylene rings. Monoacenaphthoporphyrins (41) have three Soret bands at 387, 431 and 454 nm, and the longest wavelength Q band is shifted to 658 nm. opp-Diacenaphthoporphyrin (43) further shifts these bands with two Soret absorbances at 443 and 470 nm, and an additional strong peak is observed at 692 nm. The metal complexes of these systems also show strong bands between 602 and 656 nm. Still larger effects are produced by tetraacenaphthoporphyrin (47), the dication for which in trifluoroacetic acid (TFA)–chloroform has a Soret absorption at 528 nm. Tetraaryltetraacenaphthoporphyrins (48) are even more red shifted, showing Soret bands between 556 and 570 nm for the free bases and 565 to 588 nm for the related dications. The lead(II) chelate for tetraphenylporphyrin (48a) shows an additional 'hyper' spectral shift that brings the Soret band to 604 nm, and this effect can also be achieved by introducing four meso-phenylethynyl substituents onto the tetraacenaphthoporphyrin nucleus (49). In addition, by combining these two factors for the lead(II) chelate of 49, a record-breaking value for the Soret band of 642 nm can be achieved. Spectral shifts due to ring annelation in porphyrin analogues are also discussed, including those for oxybenziporphyrins, oxypyriporphyrins, carbaporphyrins and sapphyrins.

scholarly journals Interpretations of cosmological spectral shifts

Open Physics ◽  
2013 ◽  
Vol 11 (3) ◽  
Author(s):  
Dag Østvang
Keyword(s):  
Hyperbolic Space ◽  
Spectral Shift ◽  
Space Time ◽  
Flat Connection ◽  
Closed Space ◽  
Spectral Shifts

AbstractIt is shown that for Robertson-Walker models with flat or closed space sections, all of the cosmological spectral shift can be attributed to the non-flat connection (and thus indirectly to space-time curvature). For Robertson-Walker models with hyperbolic space sections, it is shown that cosmological spectral shifts uniquely split up into “kinematic” and “gravitational” parts provided that distances are small. For large distances no such unique split-up exists in general. A number of common, but incorrect assertions found in the literature regarding interpretations of cosmological spectral shifts, is pointed out.

scholarly journals Solvatochromic Study of Two Pyridazinium Ylids Binary Solutions

2016 ◽  
Vol 22 (3) ◽  
pp. 598-602
Author(s):  
Daniela Babuşca ◽  
Cezarina Ana Moroşanu ◽  
Dana Ortansa Dorohoi
Keyword(s):  
Solubility Parameter ◽  
Intramolecular Charge Transfer ◽  
Spectral Shift ◽  
Solvent Interactions ◽  
Binary Solutions ◽  
Spectral Shifts ◽  
Different Types ◽  
Linear Solvation Energy ◽  
Solvent Molecules ◽  
Parameter Values

Abstract The wavenumbers in the maximum of intramolecular charge transfer (ICT) visibile band of two pyridazinium ylids binary solutions were analized using Kamlet and Taft empirical parameters and the Hildebrand’s solubility parameter. The Hildebrand’s solubility parameter values, δH2, measures the energy needed to separate the solvent molecules. A linear solvation energy relationship (LSER) allows separating the contributions of different types of interactions to the total spectral shift. The supply of universal and specific interactions as well as the supply of solvent-solvent interactions to the total spectral shifts was calculated.

Electromagnetic radiation and inertial forces

2019 ◽  
Vol 32 (4) ◽  
pp. 480-483
Author(s):  
Nasko Elektronov ◽  
Zhivko Kushev
Keyword(s):  
Electromagnetic Radiation ◽  
Doppler Effect ◽  
Inertial Force ◽  
Spectral Shift ◽  
Inertial Forces ◽  
Spectral Shifts ◽  
Nearby Stars ◽  
The Doppler Effect

The influence of the Coriolis inertial force generated by the orbital and spin motions of distant objects on the electromagnetic radiation energies during the exchange of photons between such objects has been considered. A red or blue spectral shift occurrence in a passive observation mode that is not associated with the Doppler effect or other known effects has also been shown. The relations found are used to calculate the spectral shifts for several nearby stars from our galaxy, as well as the spectral shifts of several galaxies. The results are close to the values currently observed.

Sign in / Sign up

Export Citation Format

Share Document