3D Masked Autoencoders with Application to Anomaly Detection in Non-Contrast Enhanced Breast MRI

Self-supervised models allow (pre-)training on unlabeled data and therefore have the potential to overcome the need for large annotated cohorts. One leading self-supervised model is the masked autoencoder (MAE) which was developed on natural imaging data. The MAE is masking out a high fraction of visual transformer (ViT) input patches, to then recover the uncorrupted images as a pretraining task. In this work, we extend MAE to perform anomaly detection on breast magnetic resonance imaging (MRI). This new model, coined masked autoencoder for medical imaging (MAEMI) is trained on two non-contrast enhanced MRI sequences, aiming at lesion detection without the need for intravenous injection of contrast media and temporal image acquisition. During training, only non-cancerous images are presented to the model, with the purpose of localizing anomalous tumor regions during test time. We use a public dataset for model development. Performance of the architecture is evaluated in reference to subtraction images created from dynamic contrast enhanced (DCE)-MRI

RESEARCH ON THE CHOICE OF ECOPRODUCTIVE TECHNOLOGIES OF FOREST HARVESTING IN THE NATIONAL PARK OF SEMENIC - CHEILE CARAŞULUI

The current paper addresses the issue of choosing ecoproductive technologies of forest harvesting in the National Park of Semenic - Cheile Carasului, both through the optimal choice of the method of operation and through the system of machines used for forest harvesting from the economic, ecological and ergonomic point of view. Subsequent to the presentation of the materials and methods used, different methods of harvesting are compared in the context of ecoproductive exploitation. The selected optimal method was examined by means of a SWOT analysis through highlighting its advantages and disadvantages. After choosing the method of harvesting, the effective application of technologies of reduced environmental impact took place by choosing the optimal machine systems

RESEARCH ON THE ASSORTMENT OF THE TIMBER HARVESTED IN THE FOREST DISTRICT OF ANINA IN 2014

The paper addresses a topical issue in the analysis and comparison of results from forest harvesting in 4 lots within the Forest Distict of Anina, by methods of calculation and final measurement result in the warehouse. The research was conducted in the Forest District of Anina in the timber harvesting areas operated by logging services in 4 lots in 2014. After presenting the need, goals and objectives, the paper focuses on the research methods used and the procedure related to the determination of the industrial assortments though different methods, whose outcomes are then compared

Influence of Substrate Temperature on Structural and Morphological Properties of SnO2 Nanostructured Thin Films

SnO2 nanostructures thin films with thickness of 500 nm were prepared by electron beam-physical vapor deposition on glass substrate at temperature of 300, 373, 443, and 583 K. Structural and morphological properties of these nanostructured thin films were studied by Scanning and Transmission Electron Microscopy (SEM, TEM) and Atomic Force Microscope (AFM) methods. The changes in structural and morphological properties are found at different temperatures. Increase temperature causes important change of the structural and morphological properties. The sample prepared at 300 K has crystalline structure and the sample prepared at 583 K has amorphous structure. Roughness parameters have low values at 300, 373, 443 K as opposed to the values obtained at 583 K. This different behavior may be due to the amorphous structure of the sample that was observed in the TEM analysis

Equilibrium swelling and universal ratios in dilute polymer solutions: Exact Brownian dynamics simulations for a delta function excluded volume potential

A narrow Gaussian excluded volume potential, which tends to a delta-function repulsive potential in the limit of a width parameter d* going to zero, has been used to examine the universal consequences of excluded volume interactions on the equilibrium and linear viscoelastic properties of dilute polymer solutions. Brownian dynamics simulations data, acquired for chains of finite length, has been extrapolated to the limit of infinite chain length to obtain model independent predictions. The success of the method in predicting well known aspects of static solution properties suggests that it can be used as a systematic means by which the influence of solvent quality on both equilibrium and non-equilibrium properties can be studied.Comment: Revised version submitted to Physical Review Letters. 4 pages, 2 figures (revised with additional data