Full waveform inversion (FWI) can generate high-resolution subsurface models, but often suffers from an objective function with local minima caused mainly by an absence of low frequencies in seismograms. These local minima cause cycle skipping when the initial model for FWI is far from the true model. To avoid cycle skipping, traveltime inversion is often used to compute initial models for FWI....

A Hessian matrix in full waveform inversion (FWI) is difficult to compute directly because of high computational cost and an especially large memory requirement. Therefore, Newton-like methods are rarely feasible in realistic large-size FWI problems. We modify the quasi-Newton BFGS method to use a projected Hessian matrix that reduces both the computational cost and memory required, thereby mak...

A Hessian matrix in full waveform inversion (FWI) is difficult to compute directly because of high computational cost and an especially large memory requirement. Therefore, Newton-like methods are rarely feasible in realistic largesize FWI problems. We modify the BFGS method to use a projected Hessian matrix that reduces both the computational cost and memory required, thereby making a quasiNew...

An increasing number of burn wound infections are now due to fungi. Historically, therapy of fungal burn wound infections (FWI) consisted of debridement, topical antifungals and/or IV amphotericin B, negating the need to categorize disease further than fungal burn wound colonization (FWC) versus FWI. Newer antifungal agents have varying spectrums of activity, increasing the importance of identi...

The mining frequent itemsets plays an important role in the mining of association rules. Frequent itemsets are typically mined from binary databases where each item in a transaction may have a different significance. Mining Frequent Weighed Itemsets (FWI) from weighted items transaction databases addresses this issue. This paper therefore proposes algorithms for the fast mining of FWI from weig...

OBJECTIVE To analyze the occurrence of fungal wound infection (FWI) after thermal injury and its relationship to mortality. BACKGROUND FWI is an uncommon but potentially lethal complication of severe thermal injury. METHODS The records of patients with thermal burns admitted to a single burn center (1991-2002) were reviewed. Analyses accounted for total burn size (TBS, percentage body surfa...

Multiple problems, including high computational cost, spurious local minima, and solutions with no geologic sense, have prevented widespread application of full waveform inversion (FWI), especially FWI of seismic reflections. These problems are fundamentally related to a large number of model parameters and to the absence of low frequencies in recorded seismograms. Instead of inverting for all ...

Knowledge of changes in reservoir properties resulting from extracting hydrocarbons or injecting fluid is critical to future production planning. Full-waveform inversion (FWI) of time-lapse seismic data provides a quantitative approach to characterize the changes by taking the difference of the inverted baseline and monitor models. The baseline and monitor data sets can be inverted either indep...

OBJECTIVE To investigate and compare the prevalence of psychoses in the French West Indies (FWI) and in continental France. METHOD As part of an international epidemiologic multicentre study under the authority of the World Health Organization French Collaborating Center (WHO-CC), we questioned 7257 individuals selected from the general population in France and in the FWI, using the Mini Inte...

Full waveform inversion (FWI) is a process in which seismic data in time or frequency domain is fit by changing the velocity of the media under investigation. The problem is non-linear, and therefore optimization techniques have been used to find a geological solution to the problem. The main problem in fitting the data is the lack of low spatial frequencies. This deficiency often leads to a lo...