International Journal of Advanced Statistics and IT&C for Economics and Life Sciences

A Categorical Metamodel for Reactive Kripke Frames

Daniel-Cristian Crăciunean — Sat, 23 Dec 2023 00:00:00 +0200

In a reactive Kripke model, evaluation of logical operators can cause reconfiguration of the model in which the formula is evaluated. Therefore, in reactive Kripke frames, the evaluation of a logical formula in a world depends both on the world in which the evaluation is made and on the worlds it has passed through previously. The result is an extended semantics, which can specify a class of modal logics more comprehensive than the class specified by ordinary Kripke frames. This paper introduces a metamodel for reactive Kripke frames, based on the concept of categorical sketch. We believe that the categorical sketch is an appropriate metamodel for specifying a Kripke frame model.

Simulink implementation of the open-loop scalar command for a three-phase induction machine model

Gabriela Craciunas, Alina Cristina Viorel — Sat, 23 Dec 2023 00:00:00 +0200

This paper describes step by step the modelling and simulation of the open loop scalar command for a three-phase induction machine with known parameters, which operates in motor regime. In order to change the electromagnetic torque and implicitly the rotor speed, in this paper the solution of applying a positive mechanical torque from outside the machine was chosen, without dynamically adjusting the supply voltage. The chosen mathematical model for the induction machine is the one described by Krause's equations, written in a stationary reference frame. The simulations were done on the Matlab/Simulink simulation environment and the behaviour of the machine was monitored under the working conditions listed above.

Different Chopper Types for Supply Separately Excited DC Motor

Alina Viorel, Gabriela Crăciunaș — Sat, 23 Dec 2023 00:00:00 +0200

Nowadays saving the planet's resources plays a very important role in improving our life conditions. The purpose of the paper is to supply the separately excited dc motor by using different chopper circuits. A very sustainable solution is to replace the resistors from classic theory with dc choppers for better efficiency. The armature voltage can be controlled by using IGBT chopper and the PWM signal received from controller is done with a dedicated block created by MATLAB environment. The advantages of developing this technique are that the speed changes proportionally with armature voltage and inversely with field voltage by keeping field and armature voltage constant respectively. The chopper designed with IGBT and Diode modules offers good control at any frequency value and the speed, the armature current and electromagnetic torque of DC motor can be control. In this paper, different choppers had been simulating were working in four quadrants for supply an excited dc motor by using Matlab program.

Fog Detection through Image Processing Methods

Teodor-Adrian Radescu, Arpad Gellert — Sat, 23 Dec 2023 00:00:00 +0200

This paper presents a fog detection algorithm, highlighting the significance of continued exploration in fog identification through image processing techniques. The advancement and application of this algorithm can significantly benefit various domains, including road safety, environmental monitoring, navigation, security, surveillance, and improving existing systems' performance. The evaluation performed on test images have shown an accuracy of 72%, a precision of 94%, a recall of 57% and an F1 score of 0.71. The proposed algorithm clearly outperformed some existing fog detection methods.

Implementation of a weather station to monitor agricultural crops

Ionuț Claudiu Udrescu, Alina Cristina Viorel, Gabriela Crăciunaș, Mihai Bogdan — Sat, 23 Dec 2023 00:00:00 +0200

Various studies on local crop monitoring are presented in the literature, however there is insufficient research on low-cost IoT weather stations that can obtain weather information over a long period of time. To overcome the difficulties described above, this paper proposes the development of an IoT weather station for low-cost, sustainable and multi-functional agricultural crop monitoring.

The objective of the work is to develop a local weather observation device for agricultural crops, to set up a server for storing and providing meteorological information and to perform an analysis of the acquired weather data.

The weather station architecture developed and proposed in this project consists of four main blocks: sensor and controller module, power module, local data storage module and data communication module (gateway).

An Overview of Sound Features in Time and Frequency Domain

Constantin Constantinescu, Remus Brad — Sat, 23 Dec 2023 00:00:00 +0200

Sound is the result of mechanical vibrations that set air molecules in motion, causing variations in air pressure that propagate as pressure waves. Represented as waveforms, these visual snapshots of sound reveal some of its characteristics. While waveform analysis offers limited insights, audio features provide a quantitative and structured way to describe sound, enabling data-driven analysis and interpretation. Different audio features capture various aspects of sound, facilitating a comprehensive understanding of the audio data. By leveraging audio features, machine learning models can be trained to recognize patterns, classify sounds, or make predictions, enabling the development of intelligent audio systems. Time-domain features, e.g., amplitude envelope, capture events from raw audio waveforms. Frequency domain features, like band energy ratio and spectral centroid, focus on frequency components, providing distinct information. In this paper, we will describe three time-domain and three frequency-domain features that we consider crucial and widely used. We will illustrate the suitability of each feature for specific tasks and draw general conclusions regarding the significance of sound features in the context of machine learning.

Sentiment Analysis Using Bert Model

Manuel-Ilie Dorca, Antoniu Gabriel Pitic; Radu G. Cretulescu — Sat, 23 Dec 2023 00:00:00 +0200

The topic of this presentation entails a comprehensive investigation of our sentiment analysis algorithm. The document provides a thorough examination of its theoretical underpinnings, meticulous assessment criteria, consequential findings, and an enlightening comparative analysis. Our system makes a substantial contribution to the field of sentiment analysis by using advanced techniques based on deep learning and state-of-the-art architectures.

Methods for data validation using QR codes

Vlad Andrei Oleksik, Elena Alina Pitic, Radu G. Cretulescu — Sat, 23 Dec 2023 00:00:00 +0200

This article aims to elaborate on a few strategies designed for validating data encoded as a QR code. As the use-cases for such validation schemes vary widely as the demand for such practices is continuously increasing, the present article will represent a comparative study of checksum, hashing, as well as asymmetric encryption algorithms for the offline validation of claims transmitted through the payload of the exchanged data. Results are evaluated based on different criteria impacting the reliability, such as the size of the QR code and the resulting security.