Search results for "Computer Science Application"
showing 10 items of 3998 documents
Long- and short-term stability of all polarization-maintaining thulium doped passively mode-locked fiber lasers with emission wavelengths at 1.95 µm …
2023
In this work, we compare the operation of a passively modelocked polarization-maintaining emission in two thulium-doped fiber lasers pumped at 1561 nm, with emission at wavelengths of 1.951 μm in one case and 2.07 μm in the other. We obtained a sequence of light pulses at 15.6 MHz, whose temporal width was 81 ps at 1.95 μm, and a sequence of light pulses at 13.1 MHz, whose temporal width was 94 ps at 2.07 μm. Finally, we also measured the long-term stability of this setup during a 24-h operation, as well as the short-term stability in a simulated harsh environment. The results confirm the superior performance of fiber laser systems with a fully polarization-maintaining design.
Nanovised Control Flow Attestation
2022
This paper presents an improvement of control flow attestation (C-FLAT) for Linux. C-FLAT is a control attestation system for embedded devices. It was implemented as a software executing in ARM’s TrustZone on bare-metal devices. We extend the design and implementation of C-FLAT through the use of a type 2 Nanovisor in the Linux operating system. We call our improved system “C-FLAT Linux”. Compared to the original C-FLAT, C-FLAT Linux reduces processing overheads and is able to detect the SlowLoris attack. We describe the architecture of C-FLAT Linux and provide extensive measurements of its performance in benchmarks and real-world scenarios. In addition, we demonstrate the…
Robustness Analysis of DCE-MRI-Derived Radiomic Features in Breast Masses: Assessing Quantization Levels and Segmentation Agreement
2022
Featured Application The use of highly robust radiomic features is fundamental to reduce intrinsic dependencies and to provide reliable predictive models. This work presents a study on breast tumor DCE-MRI considering the radiomic feature robustness against the quantization settings and segmentation methods. Machine learning models based on radiomic features allow us to obtain biomarkers that are capable of modeling the disease and that are able to support the clinical routine. Recent studies have shown that it is fundamental that the computed features are robust and reproducible. Although several initiatives to standardize the definition and extraction process of biomarkers are ongoing, th…
Deep Learning Architectures for Diagnosis of Diabetic Retinopathy
2023
For many years, convolutional neural networks dominated the field of computer vision, not least in the medical field, where problems such as image segmentation were addressed by such networks as the U-Net. The arrival of self-attention-based networks to the field of computer vision through ViTs seems to have changed the trend of using standard convolutions. Throughout this work, we apply different architectures such as U-Net, ViTs and ConvMixer, to compare their performance on a medical semantic segmentation problem. All the models have been trained from scratch on the DRIVE dataset and evaluated on their private counterparts to assess which of the models performed better in the segmentatio…
Meshless Electrophysiological Modeling of Cardiac Resynchronization Therapy—Benchmark Analysis with Finite-Element Methods in Experimental Data
2022
Computational models of cardiac electrophysiology are promising tools for reducing the rates of non-response patients suitable for cardiac resynchronization therapy (CRT) by optimizing electrode placement. The majority of computational models in the literature are mesh-based, primarily using the finite element method (FEM). The generation of patient-specific cardiac meshes has traditionally been a tedious task requiring manual intervention and hindering the modeling of a large number of cases. Meshless models can be a valid alternative due to their mesh quality independence. The organization of challenges such as the CRT-EPiggy19, providing unique experimental data as open access, enables b…
HyperIO: A Hypervisor-Based Framework for Secure IO
2023
Malware often attempts to steal input and output through human interface devices to obtain confidential information. We propose to use a thin hypervisor, called “HyperIO”, to realize a secure path between input and output devices using a partial implementation of device drivers. We apply our approach using two security systems built on HyperIO: FireSafe and ClipCrypt. FireSafe is a web browser extension which allows a remote web server to display and receive sensitive user information securely. ClipCrypt enables the user to securely enter and view their confidential information in commodity Windows applications.
Converging paths to Notes
1995
The nature of the information systems needed in a networked firm is not well known: nor is the process leading to particular solutions. Describes a small computer‐consulting company which works as a network of independent consultants, and analyses the slow and circuitous path from recognizing its IS/IT needs to its commitment to a particular solution as seven steps; using ideas of structuration theory as a focus. During the selection process, participants formed new interpretations of the firm, of technology, and of the appropriate process towards a feasible solution. New resources – both material and symbolic – were acquired to enable the search. Existing “norms” provided boundaries for th…
Special Section on ITS Services to Smart City Context [Guest Editorial]
2018
The seven articles in this special section focus on new trends and developments in the intelligent transportation markets. Since the earliest of times, transportation has changed and revolutionized society and industry. Many of technology advances were focused on transportation and their means (road, rail, air, water, etc.) even, today there exist several areas of the knowledge that are focused on it. As time goes by, new terms have been established where technology is present as well, for instance, Intelligent Transportation Systems (ITS), Smart Cities, Smart Territory, Blockchain, Internet of Things, virtualization, Cloud computing, Intelligent Vehicles, embedded computing, Deep learning,…
Estimation of formamide harmonic and anharmonic modes in the Kohn-Sham limit using the polarization consistent basis sets.
2010
Formamide harmonic and anharmonic frequencies of fundamental vibrations in the gas phase and in several solvents were successfully estimated in the B3LYP Kohn-Sham complete basis set limit (KS CBS). CBS results were obtained by extrapolating a power function (two-parameter formula) to the results calculated with polarization-consistent basis sets. Anharmonic corrections using the second order perturbation treatment (PT2) and hybrid B3LYP functional combined with polarization consistent pc-n (n = 0, 1, 2, 3, 4) and several Pople’s basis sets were analyzed for all fundamental formamide vibrational modes in the gas phase and solution. Solvent effects were modeled within a PCM method. The anhar…
Ammonium formate-Pd/C as a new reducing system for 1,2,4-oxadiazoles. Synthesis of guanidine derivatives and reductive rearrangement to quinazolin-4-…
2021
1,2,4-Oxadiazole is a heterocycle with wide reactivity and many useful applications. The reactive O-N bond is usually reduced using molecular hydrogen to obtain amidine derivatives. NH4CO2H-Pd/C is here demonstrated as a new system for the O-N reduction, allowing us to obtain differently substituted acylamidine, acylguanidine and diacylguanidine derivatives. The proposed system is also effective for the achievement of a reductive rearrangement of 5-(2′-aminophenyl)-1,2,4-oxadiazoles into 1-alkylquinazolin-4(1H)-ones. The alkaloid glycosine was also obtained with this method. The obtained compounds were preliminarily tested for their biological activity in terms of their cytotoxicity, induce…