Diffuse Optical Tomography System in Soft Tissue Tumor Detection

Topical review of recent trends in Modeling and Regularization methods of Diffuse Optical Tomography (DOT) system promotes the optimization of the forward and inverse modeling methods which provides a 3D cauterization at a faster rate of 40frames/second with the help of a laser torch as a hand-held device. Analytical, Numerical and Statistical methods are reviewed for forward and inverse models in an optical imaging modality. The advancement in computational methods is discussed for forward and inverse models along with Optimization techniques using Artificial Neural Networks (ANN), Genetic Algorithm (GA) and Artificial Neuro Fuzzy Inference System (ANFIS). The studies carried on optimization techniques offers better spatial resolution which improves quality and quantity of optical images used for morphological tissues comparable to breast and brain in Near Infrared (NIR) light. Forward problem is based on the location of sources and detectors solved statistically by Monte Carlo simulations. Inverse problem or closeness in optical image reconstruction is moderated by different regularization techniques to improve the spatial and temporal resolution. Compared to conventional methods the ANFIS structure of optimization for forward and inverse modeling provides early detection of Malignant and Benign tumor thus saves the patient from the mortality of the disease. The ANFIS technique integrated with hardware provides the dynamic 3D image acquisition with the help of NIR light at a rapid rate. Thereby the DOT system is used to continuously monitor the Oxy and Deoxyhemoglobin changes on the tissue oncology.

Supplemental Material: Tectonic controls on basement exhumation in the southern Rocky Mountains (United States): The power of combined zircon (U-Th)/He and K-feldspar 40Ar/39Ar thermochronology

Detailed forward and inverse modeling methods, and Tables S1–S4 (K-feldspar sample information and analytical data, ZHe data, and complete ZHe modeling inputs, assumptions, and modeling parameters).<br>

Supplemental Material: Tectonic controls on basement exhumation in the southern Rocky Mountains (United States): The power of combined zircon (U-Th)/He and K-feldspar 40Ar/39Ar thermochronology

Detailed forward and inverse modeling methods, and Tables S1–S4 (K-feldspar sample information and analytical data, ZHe data, and complete ZHe modeling inputs, assumptions, and modeling parameters).<br>

Nearly constant Q models of the generalized standard linear solid type and the corresponding wave equations

Time-domain seismic forward and inverse modeling for a dissipative medium is a vital research topic to investigate the attenuation structure of the Earth. Constant Q, also called frequency independence of the quality factor, is a common assumption for seismic Q inversion. We propose the first- and second-order nearly constant Q dissipative models of the generalized standard linear solid type, using a novel Q-independent weighting function approach. The two new models, which originate from the Kolsky model (a nearly constant Q model) and the Kjartansson model (an exactly constant Q model), result in the corresponding wave equations in differential form. Even for extremely strong attenuation (e.g., Q = 5), the quality factor and phase velocity for the two new models are close to those for the Kolsky and Kjartansson models, in a frequency range of interest. The wave equations for the two new models involve explicitly a specified Q parameter and have compact and simple forms. We provide a novel perspective on how to build a nearly constant Q dissipative model which is beneficial for time-domain large scale wavefield forward and inverse modeling. This perspective could also help obtain other dissipative models with similar advantages. We also discuss the extension beyond viscoacousticity and other related issues, for example, extending the two new models to viscoelastic anisotropy.

GRV_D_inv: A graphical user interface for 3D forward and inverse modeling of gravity data

This paper presents a new gravity inversion tool GRV_D_inv, specifically a GUI-based Matlab code developed to determine the three-dimensional depth structure of a density interface. The algorithm used performs iteratively in the frequency-domain based on a relationship between the Fourier transforms of the gravity data and the sum of the Fourier transforms of the powers of the depth to the interface. In this context, the proposed code is time-efficient in computations, and thus, it is capable of handling large arrays of data. The GUI-enabled interactive control functions of the code enable the user with easy control in setting the parameters for the inversion strategy prior the operation, and allow optional choice for displaying and recording of the outputs data without requiring coding expertise. We validated the code by applying it to both noise-free and noisy synthetic gravity data produced by a density interface; we obtained good correlation between the calculated ones and the actual relief even in the presence of noise. We also applied the code to a real gravity data from Brittany (France) for determining the 3D Moho interface as a practical example. The recovered depths from the code compare well with the published Moho structures of this study area.

Constraining ice shelf basalt melting rates from isochrone data

&lt;p&gt;Ice shelves buttress ice flow from the continent towards the ocean, and their disintegration results in increased ice discharge.&amp;#160; Ice-shelf evolution and integrity is influenced by surface accumulation, basal melting, and ice dynamics. We find signals of all of these processes imprinted in the ice-shelf stratigraphy that can be mapped using isochrones imaged with radar.&lt;/p&gt;&lt;p&gt;Our aim is to develop an inverse approach to infer ice shelf basal melt rates using radar isochrones as observational constraints. Here, we investigate the influence of basalt melt rates on the shape of isochrones using combined insights from both forward and inverse modeling. We use the 3D full Stokes model Elmer/Ice in our forward simulations, aiming to reproduce isochrone patterns observed in our data. Moreover we develop an inverse approach based on the shallow shelf approximating, aiming to constrain basal melt rates using isochronal radar data and surface velocities. Insights obtained from our simulations can also guide the collection of new radar data (e.g., profile lines along vs. across-flow) in a way that ambiguities in interpreting the ice-shelf stratigraphy can be minimized. Eventually, combining these approaches will enable us to better constrain the magnitude and history of basal melting, which will give valuable input for ocean circulation and sea level rise projections.&lt;/p&gt;

QUALITATIVE AND QUANTITATIVE INTERPRETATION OF HAND-DIGITIZED AEROMAGNETIC DATA FROM IDAH

Qualitative and Quantitative interpretation of hand-digitized aeromagnetic data from Idah has been carried out by applying forward and inverse modeling technique. Qualitatively, wavelength and amplitudes of source bodies reveal lithologic contrast, basement structure and sedimentary magnetization contrast. The maximum depth to top of the magnetic source body obtained is 16.8m and minimum depth is 0.5m. The anomalous bodies’ total magnetic intensity ranges from a minimum negative peak value of -153.5nT to maximum value of 162.7nT. Susceptibility values obtained reveals the presence of rocks such as granite, diabase, olivine-diabase, basalt/gabbro, quartzite and diorite. Results obtained shows that hand-digitized data competes favorably with computer digitized data

Utility of forward and inverse modeling in 2D electric tomography for Hydrogeologic studies

The choice of adequate techniques and arrays in electric tomography prospection is a difficult task; it depends generally on subsurface geology and the referred objective, this study is conducted in southern Algerian Sahara aquifer using 2D electric tomography techniques, the goal is testing different arrays configuration, using 2D model simulating the subsurface geology, the validated parameters from the theoretical study are applied to the real data, the results attest the usefulness of synthetic modeling choosing the correct parameters in geophysical prospection.

DELINEATION OF FAULTS AND CAVITIES USING GRAVITY TECHNIQUES: AN IMPLICATION FOR ROAD CONSTRUCTION, SOUTH-SOUTH NIGERIA

This study was carried out using five digitized aerogravity data to delineate near-surface structural faults, cavities, low-density zones and estimate the mass balance unit in foundations. Qualitative and quantitative analysis were performed in order to examines the depths to anomalous bodies, density/mass and stratigraphic features such as faults and cavities. The techniques employed were: Source parameter imaging (SPI), 3D Euler deconvolution, forward and inverse modeling. The results of the SPI shallow values range from -5.62 to -53.74 m and deep values range from 3.33 to 120 m. The 3D Euler deconvolution results range from -1892.2 to -1278.3 m for obscure and -12264 to 644.6 m for superficial formations. The forward and inverse modeling result shows the values of depth ranging from 2.5 to 4.8 km, density/mass range from (0.7 to 2.4) x 10-3 kg/m3 and (27 to 133) x 1010 kg of three profiles which is the parameter contrast of the gravity surveys. This shows sequential depths and density/mass contrast between the body of interest and the surrounding material which depicts the presents of faults, sedimentary basins and rock bearing minerals of shale/marble which comprises of air, water and sediment-filled formations. The information from this study has revealed the true nature of the subsurface and this will serve as a guide during road construction.