Implicit modeling of salinity reconstruction by using 3D combined models

Skull-base chordoma (SBC) can be treated with carbon ion radiotherapy (CIRT) to improve local control (LC). The study aimed to explore the role of multi-parametric radiomic, dosiomic and clinical features as prognostic factors for LC in SBC patients undergoing CIRT. Before CIRT, 57 patients underwent MR and CT imaging, from which tumour contours and dose maps were obtained. MRI and CT-based radiomic, and dosiomic features were selected and fed to two survival models, singularly or by combining them with clinical factors. Adverse LC was given by in-field recurrence or tumour progression. The dataset was split in development and test sets and the models’ performance evaluated using the concordance index (C-index). Patients were then assigned a low- or high-risk score. Survival curves were estimated, and risk groups compared through log-rank tests (after Bonferroni correction α = 0.0083). The best performing models were built on features describing tumour shape and dosiomic heterogeneity (median/interquartile range validation C-index: 0.80/024 and 0.79/0.26), followed by combined (0.73/0.30 and 0.75/0.27) and CT-based models (0.77/0.24 and 0.64/0.28). Dosiomic and combined models could consistently stratify patients in two significantly different groups. Dosiomic and multi-parametric radiomic features showed to be promising prognostic factors for LC in SBC treated with CIRT.

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MRI-Based Radiomics Analysis for the Pretreatment Prediction of Pathologic Complete Tumor Response to Neoadjuvant Systemic Therapy in Breast Cancer Patients: A Multicenter Study

Cancers ◽

10.3390/cancers13102447 ◽

2021 ◽

Vol 13 (10) ◽

pp. 2447

Author(s):

Renée W. Y. Granzier ◽

Abdalla Ibrahim ◽

Sergey P. Primakov ◽

Sanaz Samiei ◽

Thiemo J. A. van Nijnatten ◽

...

Keyword(s):

Breast Cancer ◽

Cancer Patients ◽

Systemic Therapy ◽

Tumor Response ◽

Added Value ◽

Breast Cancer Patients ◽

Neoadjuvant Systemic Therapy ◽

Clinical Models ◽

Combined Models ◽

Complete Tumor

This retrospective study investigated the value of pretreatment contrast-enhanced Magnetic Resonance Imaging (MRI)-based radiomics for the prediction of pathologic complete tumor response to neoadjuvant systemic therapy in breast cancer patients. A total of 292 breast cancer patients, with 320 tumors, who were treated with neo-adjuvant systemic therapy and underwent a pretreatment MRI exam were enrolled. As the data were collected in two different hospitals with five different MRI scanners and varying acquisition protocols, three different strategies to split training and validation datasets were used. Radiomics, clinical, and combined models were developed using random forest classifiers in each strategy. The analysis of radiomics features had no added value in predicting pathologic complete tumor response to neoadjuvant systemic therapy in breast cancer patients compared with the clinical models, nor did the combined models perform significantly better than the clinical models. Further, the radiomics features selected for the models and their performance differed with and within the different strategies. Due to previous and current work, we tentatively attribute the lack of improvement in clinical models following the addition of radiomics to the effects of variations in acquisition and reconstruction parameters. The lack of reproducibility data (i.e., test-retest or similar) meant that this effect could not be analyzed. These results indicate the need for reproducibility studies to preselect reproducible features in order to properly assess the potential of radiomics.

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Characterization of a Shallow Coastal Aquifer in the Framework of a Subsurface Storage and Soil Aquifer Treatment Project Using Electrical Resistivity Tomography (Port de la Selva, Spain)

Applied Sciences ◽

10.3390/app11062448 ◽

2021 ◽

Vol 11 (6) ◽

pp. 2448

Author(s):

Alex Sendrós ◽

Aritz Urruela ◽

Mahjoub Himi ◽

Carlos Alonso ◽

Raúl Lovera ◽

...

Keyword(s):

Electrical Resistivity ◽

Water Reuse ◽

Electrical Resistivity Tomography ◽

Groundwater Modeling ◽

Geophysical Methods ◽

Soil Aquifer Treatment ◽

Modeling Tools ◽

Resistivity Tomography ◽

Implicit Modeling ◽

The Difference

Water percolation through infiltration ponds is creating significant synergies for the broad adoption of water reuse as an additional non-conventional water supply. Despite the apparent simplicity of the soil aquifer treatment (SAT) approaches, the complexity of site-specific hydrogeological conditions and the processes occurring at various scales require an exhaustive understanding of the system’s response. The non-saturated zone and underlying aquifers cannot be considered as a black box, nor accept its characterization from few boreholes not well distributed over the area to be investigated. Electrical resistivity tomography (ERT) is a non-invasive technology, highly responsive to geological heterogeneities that has demonstrated useful to provide the detailed subsurface information required for groundwater modeling. The relationships between the electrical resistivity of the alluvial sediments and the bedrock and the difference in salinity of groundwater highlight the potential of geophysical methods over other more costly subsurface exploration techniques. The results of our research show that ERT coupled with implicit modeling tools provides information that can significantly help to identify aquifer geometry and characterize the saltwater intrusion of shallow alluvial aquifers. The proposed approaches could improve the reliability of groundwater models and the commitment of stakeholders to the benefits of SAT procedures.

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Auto-correlation robustness of factorial designs and GAMS in studying the effects of process variables in a dual-objective adsorption system

Applied Water Science ◽

10.1007/s13201-020-01349-2 ◽

2021 ◽

Vol 11 (2) ◽

Author(s):

Mutiu Kolade Amosa ◽

Fatai A. Aderibigbe ◽

Adewale George Adeniyi ◽

Joshua O. Ighalo ◽

Bisola Taibat Bello ◽

...

Keyword(s):

Wastewater Treatment ◽

Factorial Design ◽

Contact Time ◽

Factorial Designs ◽

Adsorption System ◽

Process Variables ◽

Operating Variables ◽

Auto Correlation ◽

General Algebraic Modeling System ◽

Combined Models

AbstractThe performance of factorial designs is still limited due to some uncertainties that usually intensify process complexities, hence, the need for inter-platform auto-correlation analyses. In this study, the auto-correlation capabilities of factorial designs and General Algebraic Modeling System (GAMS) on the effects of some pertinent operating variables in wastewater treatment were compared. Individual and combined models were implemented in GAMS and solved with the trio of BARON, CPLEX and IPOPT solvers. It is revealed that adsorbent dosage had the highest effect on the process. It contributed the most effect toward obtaining the minimum silica and TDS contents of 13 mg/L and 814 mg/L, and 13.6 mg/L and 815 mg/L from factorial design and GAMS platforms, respectively. This indicates a concurrence between the results from the two platforms with percentage errors of 4.4% and 0.2% for silica and TDS, respectively. The effects of the mixing speed and contact time are negligible.

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Combined Tomography and Epithelial Thickness Mapping for Diagnosis of Keratoconus

European Journal of Ophthalmology ◽

10.5301/ejo.5000850 ◽

2016 ◽

Vol 27 (2) ◽

pp. 129-134 ◽

Cited By ~ 14

Author(s):

Ronald H. Silverman ◽

Raksha Urs ◽

Arindam RoyChoudhury ◽

Timothy J. Archer ◽

Marine Gobbe ◽

...

Keyword(s):

Discriminant Analysis ◽

Corneal Thickness ◽

High Frequency Ultrasound ◽

Combined Model ◽

Variable Model ◽

Linear Discriminant ◽

Combined Models ◽

Combining Information ◽

Variance Explained ◽

Frequency Ultrasound

Purpose Scanning Scheimpflug provides information regarding corneal thickness and 2-surface topography while arc-scanned high-frequency ultrasound allows depiction of the epithelial and stromal thickness distributions. Both techniques are useful in detection of keratoconus. Our aim was to develop and test a keratoconus classifier combining information from both methods. Methods We scanned 111 normal and 30 clinical keratoconus subjects with Artemis-1 and Pentacam data. After selecting one random eye per subject, we performed stepwise linear discriminant analysis on a dataset combining parameters generated by each method to obtain classification models based on each technique alone and in combination. Results Discriminant analysis resulted in a 4-variable model (R2 = 0.740) based on Artemis data alone and a 4-variable model (R2 = 0.734) using Pentacam data alone. The combined model (R2 = 0.828) consisted of 3 Artemis- and 4 Pentacam-derived variables. The combined model R value was significantly higher than either model alone (p = 0.031, one-tailed). In cross-validation, Artemis had 100% sensitivity and 99.2% specificity, Pentacam had 97.3% sensitivity and 98.0% specificity, and the combined model had 97.3% sensitivity and 100% specificity. Conclusions Pentacam, Artemis, and combined models were all effective in distinguishing normal from clinical keratoconus subjects. From the standpoint of variance explained by the model (R2 values), the combined model was most effective. Application of the model to early and subclinical keratoconus will ultimately be required to assess the effectiveness of the combined approach.

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Mathematical Modeling for Lateral Displacement Induced by Wind Velocity Using Monitoring Data Obtained from Main Girder of Sutong Cable-Stayed Bridge

Mathematical Problems in Engineering ◽

10.1155/2014/723152 ◽

2014 ◽

Vol 2014 ◽

pp. 1-16

Author(s):

Gao-Xin Wang ◽

You-Liang Ding

Keyword(s):

Time Series ◽

Wind Velocity ◽

Lateral Displacement ◽

Third Order ◽

Nonlinear Correlation ◽

Cable Stayed Bridge ◽

Spectrum Density ◽

Combined Models ◽

Main Girder ◽

Correlation Term

Based on the health monitoring system installed on the main span of Sutong Cable-Stayed Bridge, GPS displacement and wind field are real-time monitored and analyzed. According to analytical results, apparent nonlinear correlation with certain discreteness exists between lateral static girder displacement and lateral static wind velocity; thus time series of lateral static girder displacement are decomposed into nonlinear correlation term and discreteness term, nonlinear correlation term of which is mathematically modeled by third-order Fourier series with intervention of lateral static wind velocity and discreteness term of which is mathematically modeled by the combined models of ARMA(7,4)and EGARCH(2,1). Additionally, stable power spectrum density exists in time series of lateral dynamic girder displacement, which can be well described by the fourth-order Gaussian series; thus time series of lateral dynamic girder displacement are mathematically modeled by harmonic superposition function. By comparison and verification between simulative and monitoring lateral girder displacements from September 1 to September 3, the presented mathematical models are effective to simulate time series of lateral girder displacement from main girder of Sutong Cable-Stayed Bridge.

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Analysis of the oscillatory behaviour of an industrial reactor for oxonation of propene; Combined models

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19872865 ◽

1987 ◽

Vol 52 (12) ◽

pp. 2865-2875

Author(s):

Josef Horák ◽

Zdeněk Bělohlav ◽

Petr Rosol ◽

František Madron

Keyword(s):

Liquid Phase ◽

Dynamic Behaviour ◽

Plug Flow ◽

Equal Size ◽

Mixed System ◽

Oscillatory Behaviour ◽

Industrial Reactor ◽

Combined Models ◽

Analysis Of Stability ◽

Flow Element

Models have been used of the flow of the liquid phase in the reactor (cascade of two ideally mixed cells of different size, two equal-size cells with recycle, two equal-size cells with inlets to both cells and a model of two equal-size cells preceded with a back flow element with plug flow) to analyze the oscillatory states of an industrial reactor. Stable and instable steady states have been classified using analysis of pseudosteady states of conversion and temperature supplemented with a simulation of the dynamic behaviour. It has been that the deviations of the flow from an ideally mixed system may expand the region of the oscillatory behaviour. The detailed information about the character of the flow in the reactor and the way of feeding the reactor has been also found important for the analysis of stability.

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