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Publicações

2024

Cascade PID Controllers Applied on Level and Flow Systems in a SMAR Didactic Plant

Autores
de Bem, RR; dos Santos, MF; Mercorelli, P; Martins, FN; Neto, AFD; Lima, JLSD;

Publicação
2024 25TH INTERNATIONAL CARPATHIAN CONTROL CONFERENCE, ICCC 2024

Abstract
The practical application of knowledge acquired during undergraduate studies is crucial for students to address real-world problems and seek solutions. The SMAR PD3 didactic plant provides a conducive environment for experiments in systems such as level and flow, common in various industrial sectors. Cascade control, an approach that sequentially uses two or more controllers, stands out as a promising strategy to enhance precision and stability in industrial processes. This work proposes a study on cascade control in flow and level systems, demonstrating its application in the didactic plant. The process involved system identification, tuning of conventional and cascade PI and PID controllers, followed by the implementation of the Successive Loop Closure technique. Results, in line with specialized literature, indicate that the implementation of cascade controllers in the industry can improve specific processes affected by disturbances or changes in variables, directly impacting the overall functioning of the process.

2024

State Estimation Extensive Criticality Analysis Performed on Measuring Units: A Comparative Study

Autores
Nishio, A; Do Coutto, MB; de Souza, JCS; Pereira, J; Zanghi, E;

Publicação
JOURNAL OF CONTROL AUTOMATION AND ELECTRICAL SYSTEMS

Abstract
As one of the functions integrating energy management systems, state estimation (SE) is instrumental in monitoring power networks, allowing the best possible use of energy resources. It plays a decisive role in debugging if sufficient data are available, ruined if not. Criticality analysis (CA) integrates SE as a module in which elements of the estimation process-taken one-by-one or grouped (tuples of minimal multiple cardinality)-are designated essential. The combinatorial nature of extensive CA (ExtCA), derestricted from identifying only low-cardinality critical tuples, characterizes its computational complexity and imposes defiant limits in implementing it. This paper presents the methodology for ExtCA and compares algorithms to find an efficient solution for expanding the boundaries of this analysis problem. The algorithms used for comparison are one sequential Branch&Bound (a well-known paradigm for combinatorial optimization recently used in ExtCA) and two new parallels implemented on the central processing unit (CPU) and the graphics processing unit (GPU). The conceived parallel architecture favors evaluating massive combinations of diverse cardinality measuring unit (MU) tuples in ExtCA. The acronym MU refers to the aggregate of devices deployed at substations, such as a remote terminal unit, intelligent electronic device, and phasor measurement unit. The numerical results obtained in the paper show significant speed-ups with the novel parallel GPU algorithm, tested on different and real-scale power grids. Since, the visualization of the ExtCA results is still not a well-explored field, this work also presents a novel way of graphically depicting spots of weak observability using MU-oriented ExtCA.

2024

Cyber-Resilience in the Context of National Security and Defense; [Ciber-Resiliência no Contexto da Segurança e Defesa Nacionais]

Autores
Pavão, J; Bastardo, R; Carreira, D; Rocha, NP;

Publicação
RISTI - Revista Iberica de Sistemas e Tecnologias de Informacao

Abstract
Cyber-resilience is a relatively recent concept that, in essence, adds risk management to the cybersecurity concept and extends the scope of its action to processes and people, in addition to the technological component. It aims to ensure that organizations, systems, and especially critical infrastructures of our society function properly regardless of their dependence on cybernetic resources that may be affected by adverse events. Considering that the ongoing digital transition increases the exposure of such infrastructures to physical and cyberspace threats, this article reports on an exploratory study supported by bibliographical research, which aimed to analyze recent scientific publications to determine the relevance of cyber-resilience in the context of national security and defense. Although the number of publications focused on cyber-resilience is still relatively reduced when compared to the number of publications related to cybersecurity, there is a growing interest in exploring cyber-resilience in areas such as international relations, internal security, and national defense, which are fundamental pillars of the security and defense of States. © 2024, Associacao Iberica de Sistemas e Tecnologias de Informacao. All rights reserved.

2024

Bespoke cultivation of seablite with digital agriculture and machine learning

Autores
Chaichana, T; Reeve, G; Drury, B; Chakrabandhu, Y; Wangtueai, S; Yoowattana, S; Sookpotharom, S; Boonnam, N; Brennan, CS; Muangprathub, J;

Publicação
ECOLOGICAL INDICATORS

Abstract
Climate change has driven agriculture to alter farming methods for food production. This paper presents a new concept for monitoring, acquisition, management, analysis, and synthesis of ecological data, which captures the environmental determinants and direct gradients suited to a particular requirement for specific plant cultivation and sustainable agriculture. The purpose of this study is to investigate a smart seablite cultivation system. A novel digital agricultural method was developed and applied to digitised seablite cultivation. Machine learning was used to predict the future growth conditions of plants (seablites). The study identified the illustrative maps of seablite origins, a conceptual seablite smart farming model, essential factors for growing seablite, a digital circuit for cultivating seablite, and digital data of seablite growth phases comprised the digital data. The findings indicate that: (1) An indicator of soil salinity is a quantity of sodium chloride extracted from a seablite sample indicating its origin of environmental determinants. (2) Saline soil, saline water, pH, moisture, temperature, and sunlight are essential factors for seablite development. These factors are dependent on climate change and were measured using a smart seablite cultivation system. (3) Digital circuits of seablite cultivation provide a better understanding of the relationship between the essential factors for seablite growth and seablite growth phases. (4) Deep neural networks outperformed vector machines, with 86% accuracy at predicting future growth of seablites. Therefore, this finding showed that the essential seablite development factors can be manipulated as key controllers for agriculture in response to climate change and agriculture can be planned. Basic digitisation of specific plants aids plant migration. Digital agriculture is an important practice for agroecosystems.

2024

A dynamic reference voltage adjustment strategy for Open-UPQC to increase hosting capacity of electrical distribution networks

Autores
Kazemi-Robati, E; Hafezi, H; Faranda, R; Silva, B; Nasiri, MS;

Publicação
SUSTAINABLE ENERGY GRIDS & NETWORKS

Abstract
Future electrical grids, particularly the distribution networks, may face more severe voltage rises/drops, and in general, more power quality problems in the presence of new loads such as electric vehicle chargers and renewable energy generation units like photovoltaic systems. This necessitates investing in additional high-cost infrastructure to increase the capability of the feeder in hosting higher levels of loads and generation units while the existing capacity is not utilized effectively. In the stated condition, effective voltage stabilization strategies in electrical distribution networks can contribute to hosting capacity improvement and the better utilization of the existing infrastructure. Accordingly, in this paper, the application of Open-UPQC in voltage profile improvement and hosting capacity enhancement is evaluated in low-voltage distribution networks. Furthermore, a dynamic reference voltage adjustment strategy is applied to the device to improve its capabilities in power quality improvement and hosting capacity enhancement. Simulation studies have been implemented to evaluate the capability of Open-UPQC either with static reference voltage or the dynamically-adjusted one in low-voltage networks with real measured data while different cases are assessed regarding the topology and the length of the feeder. The simulation results approved the capability of Open-UPQC especially with the dynamic reference voltage in hosting capacity enhancement while providing the highest level of voltage profile improvement among all the assessed custom power devices in the studied low-voltage networks.

2024

Informative Classification of Capsule Endoscopy Videos Using Active Learning

Autores
Fonseca, F; Nunes, B; Salgado, M; Silva, A; Cunha, A;

Publicação
WIRELESS MOBILE COMMUNICATION AND HEALTHCARE, MOBIHEALTH 2023

Abstract
The wireless capsule endoscopy is a non-invasive imaging method that allows observation of the inner lumen of the small intestine, but with the cost of a longer duration to process its resulting videos. Therefore, the scientific community has developed several machine learning strategies to help reduce that duration. Such strategies are typically trained and evaluated on small sets of images, ultimately not proving to be efficient when applied to full videos. Labelling full Capsule Endoscopy videos requires significant effort, leading to a lack of data on this medical area. Active learning strategies allow intelligent selection of datasets from a vast set of unlabelled data, maximizing learning and reducing annotation costs. In this experiment, we have explored active learning methods to reduce capsule endoscopy videos' annotation effort by compiling smaller datasets capable of representing their content.

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