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Publicações

Publicações por CTM

2024

Optimized reconstruction of the absorption spectra of kidney tissues from the spectra of tissue components using the least squares method

Autores
Pinheiro, MR; Fernandes, LE; Carneiro, IC; Carvalho, SD; Henrique, RM; Tuchin, VV; Oliveira, HP; Oliveira, LM;

Publicação
JOURNAL OF BIOPHOTONICS

Abstract
With the objective of developing new methods to acquire diagnostic information, the reconstruction of the broadband absorption coefficient spectra (mu a[lambda]) of healthy and chromophobe renal cell carcinoma kidney tissues was performed. By performing a weighted sum of the absorption spectra of proteins, DNA, oxygenated, and deoxygenated hemoglobin, lipids, water, melanin, and lipofuscin, it was possible to obtain a good match of the experimental mu a(lambda) of both kidney conditions. The weights used in those reconstructions were estimated using the least squares method, and assuming a total water content of 77% in both kidney tissues, it was possible to calculate the concentrations of the other tissue components. It has been shown that with the development of cancer, the concentrations of proteins, DNA, oxygenated hemoglobin, lipids, and lipofuscin increase, and the concentration of melanin decreases. Future studies based on minimally invasive spectral measurements will allow cancer diagnosis using the proposed approach.

2024

Systematic review on weapon detection in surveillance footage through deep learning

Autores
Santos, T; Oliveira, H; Cunha, A;

Publicação
COMPUTER SCIENCE REVIEW

Abstract
In recent years, the number of crimes with weapons has grown on a large scale worldwide, mainly in locations where enforcement is lacking or possessing weapons is legal. It is necessary to combat this type of criminal activity to identify criminal behavior early and allow police and law enforcement agencies immediate action.Despite the human visual structure being highly evolved and able to process images quickly and accurately if an individual watches something very similar for a long time, there is a possibility of slowness and lack of attention. In addition, large surveillance systems with numerous equipment require a surveillance team, which increases the cost of operation. There are several solutions for automatic weapon detection based on computer vision; however, these have limited performance in challenging contexts.A systematic review of the current literature on deep learning-based weapon detection was conducted to identify the methods used, the main characteristics of the existing datasets, and the main problems in the area of automatic weapon detection. The most used models were the Faster R-CNN and the YOLO architecture. The use of realistic images and synthetic data showed improved performance. Several challenges were identified in weapon detection, such as poor lighting conditions and the difficulty of small weapon detection, the last being the most prominent. Finally, some future directions are outlined with a special focus on small weapon detection.

2024

Tutorial on the Use of the Photon Diffusion Approximation for Fast Calculation of Tissue Optical Properties

Autores
Pinheiro, MR; Carvalho, MI; Oliveira, LM;

Publicação
JOURNAL OF BIOPHOTONICS

Abstract
Computer simulations, which are performed at a single wavelength at a time, have been traditionally used to estimate the optical properties of tissues. The results of these simulations need to be interpolated. For a broadband estimation of tissue optical properties, the use of computer simulations becomes time consuming and computer demanding. When spectral measurements are available for a tissue, the use of the photon diffusion approximation can be done to perform simple and direct calculations to obtain the broadband spectra of some optical properties. The additional estimation of the reduced scattering coefficient at a small number of discrete wavelengths allows to perform further calculations to obtain the spectra of other optical properties. This study used spectral measurements from the heart muscle to explain the calculation pipeline to obtain a complete set of the spectral optical properties and to show its versatility for use with other tissues for various biophotonics applications.

2024

An Overview of Threats Exploring the Confusion Between Top-Level Domains and File Type Extensions

Autores
Sales, A; Torres, N; Pinto, P;

Publicação
PROCEEDINGS OF THE FOURTEENTH ACM CONFERENCE ON DATA AND APPLICATION SECURITY AND PRIVACY, CODASPY 2024

Abstract
Cyberattacks exploit deceptions involving the Domain Name Service (DNS) to direct users to fake websites, such as typosquatting attacks, which exploit natural typographical errors, and homograph attacks, where different Unicode characters resemble the legitimate ones. The deception attacks may also exploit the confusion between DNS domain names, specifically Top-Level Domains (TLDs), and file extensions. Recently, two new TLDs were added, zip and mov, sharing names with certain file types. This overlapping can be explored by malicious actors in a range of threat scenarios to compromise user security. This paper provides an overview of threats originating from the confusion between specific TLDs and file extensions, such as the recent zip and mov. The threats are grouped into 6 threat scenarios that are described and discussed. This research can be part of a more comprehensive strategy that includes addressing the risks associated with these threats and designing future strategies to address the threats associated with exploiting this ambiguity.

2024

ORAT - An Open Redirect Analysis Tool

Autores
Martinho, J; Mendes, D; Pinto, P;

Publicação
12th International Symposium on Digital Forensics and Security, ISDFS 2024

Abstract
Securing web applications against open redirect vulnerabilities is important for protecting users from malicious redirection and phishing attacks. Open Redirect attacks occur when a malicious actor manipulates a link on a vulnerable web-site to redirect users to a malicious destination, often disguised as legitimate. This paper proposes a Google Chrome extension named Open Redirect Analysis Tool (ORAT), a tool that analyses a website for potential open redirect attacks. ORAT enables the detection of such vulnerabilities directly within the browser. It uses a straightforward interface and it simplifies the process of scanning web applications for unsafe redirects by applying a curated set of test payloads to uncover vulnerabilities, from the obvious to the subtle ones. The tests show that ORAT can identify and present open redirect vulnerabilities. Also, a discussion is provided about the limitations encountered, such as the scope of testing payloads and browser specificity, and a roadmap for future iterations of the proposed tool is proposed. By advancing the capabilities for early detection of redirect vulnerabilities, ORAT contributes to the set of tools available to cybersecurity practitioners and web developers, aiming to foster a secure online environment. © 2024 IEEE.

2024

Utility Function for Assessing the Cost of Recovering from Ransomware Attacks

Autores
Pinto, L; Pinto, P; Pinto, A;

Publicação
OPTIMIZATION, LEARNING ALGORITHMS AND APPLICATIONS, OL2A 2024, PT II

Abstract
Nowadays ransomware attacks have become one of the main problems organizations face. The threat of ransomware attacks, with their capacity to paralyze entire organizations, creates the need to develop a ransomware recovery utility function to help further prepare for the impact of such attacks and enhance the organization's knowledge and perception of risk. This work proposes a ransomware recovery utility function that aims to estimate the impact of a ransomware attack measured in manpower hours till recovery and taking into account different devices and different scenarios.

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