An Inversion Method for Shallow Water Geoacoustic Parameters Based on BIC Criterion

2021 ◽  
Author(s):  
Yangyang Xue ◽  
Wenliang Wang ◽  
Hanhao Zhu ◽  
Guangxue Zheng ◽  
Zhiqiang Cui
Keyword(s):  
Shallow Water ◽  
Inversion Method ◽  
Bic Criterion

scholarly journals An Inversion Method for Geoacoustic Parameters of Multilayer Seabed in Shallow Water

2021 ◽  
Vol 1739 ◽  
pp. 012019
Author(s):  
Yangyang Xue ◽  
Fuqiang Lei ◽  
Hanhao Zhu ◽  
Rui Xiao ◽  
Chao Chen ◽  
...  
Keyword(s):  
Shallow Water ◽  
Inversion Method

TOMOGRAPHIC INVERSION FOR GEOACOUSTIC PARAMETERS IN SHALLOW WATER

2000 ◽  
Vol 08 (02) ◽  
pp. 285-293 ◽  
Author(s):  
A. TOLSTOY
Keyword(s):  
Shallow Water ◽  
Simulated Data ◽  
Environmental Parameters ◽  
Inversion Method ◽  
Future Directions ◽  
Tomographic Inversion ◽  
The Matrix ◽  
Matrix Condition Number ◽  
Matrix Condition ◽  
Tomography Inversion

This paper examines the linearized tomographic inversion of simulated data for a shallow water, multi-array, multi-source scenario. The environments represented include simulations of (1) highly idealized constant regions as well as (2) the Haro Strait Test of June 1996 which displays range, depth, and azimuthal variability, i.e., 3-D dependence on environmental parameters where these parameters can include water depths and multiple sediment sound-speed profiles, densities, depths, and attenuations. This tomographic inversion method is independent of the number of parameters to be determined. However, the method does assume that some inversion method (such as RIGS, simulated annealing, genetic algorithms, etc.) has already estimated range-independent average source-to-receiver environmental parameters. These average parameters are then input into the tomographic inversion which relies on a matrix of path-cell distances. The matrix condition number, Λ, is a determining feature for the inversion accuracy where Λ is a function of source and receiver distributions and their subsequent path distances through the region cells. Additionally, the accuracy of the input estimates for the average geoacoustic properties is also an important factor in the final 3-D tomographic inversion accuracy. Results using this (linearized) tomography inversion method show a potential for excellent error estimates (much less than 1%) for the environmental parameters assuming exact, idealized input values. Errors are still quite reasonable (well under 10%) if more realistic, i.e., erroneous, input values are assumed. This paper will conclude with a discussion of upcoming future directions.

3D inversion of marine CSEM and MT data: An approach to shallow-water problem

Geophysics ◽  
2013 ◽  
Vol 78 (1) ◽  
pp. E59-E65 ◽  
Author(s):  
Yutaka Sasaki
Keyword(s):  
Shallow Water ◽  
Water Depth ◽  
Hydrocarbon Exploration ◽  
High Resistivity ◽  
Inversion Method ◽  
Burial Depth ◽  
3D Inversion ◽  
Electric Field Amplitude ◽  
Water Problem ◽  
The Given

The application of the marine controlled-source electromagnetic (CSEM) technique for shallow-water hydrocarbon exploration is challenged by the effect of an airwave that masks the response from the reservoir at depth. We applied Gauss–Newton-based 3D inversion method to synthetic CSEM and magnetotelluric (MT) data to demonstrate the capability of 3D inversion to recover thin resistive targets in shallow-water environments. The experiment on the model with water depth of 300 m shows that the target signals at 0.25 Hz are significant enough to resolve the reservoir at a burial depth of 1 km for the given noise level (6% of the electric-field amplitude). For the 100-m water depth case, the high-resistivity zone recovered is located much deeper and thicker than the true reservoir, suggesting that the airwave component obscures the target signal more seriously. However, inverting inline and broadside data together or adding inline data at a different frequency (0.1 Hz) is quite effective in improving the resolution to the thin resistive target and more so than simultaneously inverting inline CSEM and MT data.

An inversion method of geoacoustic properties based on towed tilted line array in shallow water

2010 ◽  
Author(s):  
Kunde Yang ◽  
Yuanliang Ma ◽  
Xuegang Li ◽  
Haibin Qiu ◽  
Jeffrey Simmen ◽  
...  
Keyword(s):  
Shallow Water ◽  
Inversion Method ◽  
Line Array ◽  
Tilted Line

Formulation, Design and Development of Niosome Based Topical Gel for Skin Cancer

2017 ◽  
Vol 2 (3) ◽  
Keyword(s):  
Skin Cancer ◽  
Drug Release ◽  
Hemorrhagic Cystitis ◽  
The Body ◽  
Cancer Drug ◽  
Inversion Method ◽  
Body Parts ◽  
Basal Cells ◽  
Formulation Design ◽  
Topical Gel

Melanoma is the most dangerous type of skin cancer in which mostly damaged unpaired DNA starts mutating abnormally and staged an unprecedented proliferation of epithelial skin to form a malignant tumor. In epidemics of skin, pigment-forming melanocytes of basal cells start depleting and form uneven black or brown moles. Melanoma can further spread all over the body parts and could become hard to detect. In USA Melanoma kills an estimated 10,130 people annually. This challenge can be succumbed by using the certain anti-cancer drug. In this study design, cyclophosphamide were used as a model drug. But it has own limitation like mild to moderate use may cause severe cytopenia, hemorrhagic cystitis, neutropenia, alopecia and GI disturbance. This is a promising challenge, which is caused due to the increasing in plasma drug concentration above therapeutic level and due to no rate limiting steps involved in formulation design. In this study, we tried to modify drug release up to threefold and extended the release of drug by preparing and designing niosome based topical gel. In the presence of Dichloromethane, Span60 and cholesterol, the initial niosomes were prepared using vacuum evaporator. The optimum percentage drug entrapment efficacy, zeta potential, particle size was found to be 72.16%, 6.19mV, 1.67µm.Prepared niosomes were further characterized using TEM analyzer. The optimum batch of niosomes was selected and incorporated into topical gel preparation. Cold inversion method and Poloxamer -188 and HPMC as core polymers, were used to prepare cyclophosphamide niosome based topical gel. The formula was designed using Design expert 7.0.0 software and Box-Behnken Design model was selected. Almost all the evaluation parameters were studied and reported. The MTT shows good % cell growth inhibition by prepared niosome based gel against of A375 cell line. The drug release was extended up to 20th hours. Further as per ICH Q1A (R2), guideline 6 month stability studies were performed. The results were satisfactory and indicating a good formulation approach design was achieved for Melanoma treatment.

Spatial assemblage structure of shallow-water reef fish in Southwest Australia

2020 ◽  
Vol 649 ◽  
pp. 125-140
Author(s):  
DS Goldsworthy ◽  
BJ Saunders ◽  
JRC Parker ◽  
ES Harvey
Keyword(s):  
Shallow Water ◽  
Reef Fish ◽  
Marine Environment ◽  
Fish Assemblages ◽  
Canopy Cover ◽  
Reef Fishes ◽  
Reef Fish Assemblage ◽  
Reef Type ◽  
Present Distribution ◽  
Southwest Australia

Bioregional categorisation of the Australian marine environment is essential to conserve and manage entire ecosystems, including the biota and associated habitats. It is important that these regions are optimally positioned to effectively plan for the protection of distinct assemblages. Recent climatic variation and changes to the marine environment in Southwest Australia (SWA) have resulted in shifts in species ranges and changes to the composition of marine assemblages. The goal of this study was to determine if the current bioregionalisation of SWA accurately represents the present distribution of shallow-water reef fishes across 2000 km of its subtropical and temperate coastline. Data was collected in 2015 using diver-operated underwater stereo-video surveys from 7 regions between Port Gregory (north of Geraldton) to the east of Esperance. This study indicated that (1) the shallow-water reef fish of SWA formed 4 distinct assemblages along the coast: one Midwestern, one Central and 2 Southern Assemblages; (2) differences between these fish assemblages were primarily driven by sea surface temperature, Ecklonia radiata cover, non-E. radiata (canopy) cover, understorey algae cover, reef type and reef height; and (3) each of the 4 assemblages were characterised by a high number of short-range Australian and Western Australian endemic species. The findings from this study suggest that 4, rather than the existing 3 bioregions would more effectively capture the shallow-water reef fish assemblage patterns, with boundaries having shifted southwards likely associated with ocean warming.

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