2023
Authors
Santos, J; Figueiredo, D; Madeira, A;
Publication
THEORETICAL ASPECTS OF SOFTWARE ENGINEERING, TASE 2023
Abstract
A wide range of methods from computer science are being applied to many modern engineering domains, such as synthetic biology. Most behaviors described in synthetic biology have a hybrid nature, in the sense that both discrete or continuous dynamics are observed. Differential Dynamic Logic (dL) is a well-known formalism used for the rigorous treatment of these systems by considering formalisms comprising both differential equations and discrete assignments. Since the many systems often consider a range of values rather than exact values, due to errors and perturbations of observed quantities, recent work within the team proposed an interval version of dL, where variables are interpreted as intervals. This paper presents the first steps in the development of computational support for this formalism by introducing a tool designed to models based on intervals, prepared to translate them into specifications ready to be processed by the KeYmaera X tool.
2023
Authors
Victoriano, M; Oliveira, L; Oliveira, HP;
Publication
Pattern Recognition and Image Analysis - 11th Iberian Conference, IbPRIA 2023, Alicante, Spain, June 27-30, 2023, Proceedings
Abstract
The impact of climate change on global temperature and precipitation patterns can lead to an increase in extreme environmental events. These events can create favourable conditions for the spread of plant pests and diseases, leading to significant production losses in agriculture. To mitigate these losses, early detection of pests is crucial in order to implement effective and safe control management strategies, to protect the crops, public health and the environment. Our work focuses on the development of a computer vision framework to detect and classify the olive fruit fly, also known as Bactrocera oleae, from images, which is a serious concern to the EU’s olive tree industry. The images of the olive fruit fly were obtained from traps placed throughout olive orchards located in Greece. The approach entails augmenting the dataset and fine-tuning the YOLOv7 model to improve the model performance, in identifying and classifying olive fruit flies. A Portuguese dataset was also used to further perform detection. To assess the model, a set of metrics were calculated, and the experimental results indicated that the model can precisely identify the positive class, which is the olive fruit fly.
2023
Authors
Pimentel, J; Azevedo, PJ; Torgo, L;
Publication
EXPERT SYSTEMS
Abstract
Machine learning algorithms have shown several advantages compared to humans, namely in terms of the scale of data that can be analysed, delivering high speed and precision. However, it is not always possible to understand how algorithms work. As a result of the complexity of some algorithms, users started to feel the need to ask for explanations, boosting the relevance of Explainable Artificial Intelligence. This field aims to explain and interpret models with the use of specific analytical methods that usually analyse how their predicted values and/or errors behave. While prediction analysis is widely studied, performance analysis has limitations for regression models. This paper proposes a rule-based approach, Error Distribution Rules (EDRs), to uncover atypical error regions, while considering multivariate feature interactions without size restrictions. Extracting EDRs is a form of subgroup mining. EDRs are model agnostic and a drill-down technique to evaluate regression models, which consider multivariate interactions between predictors. EDRs uncover regions of the input space with deviating performance providing an interpretable description of these regions. They can be regarded as a complementary tool to the standard reporting of the expected average predictive performance. Moreover, by providing interpretable descriptions of these specific regions, EDRs allow end users to understand the dangers of using regression tools for some specific cases that fall on these regions, that is, they improve the accountability of models. The performance of several models from different problems was studied, showing that our proposal allows the analysis of many situations and direct model comparison. In order to facilitate the examination of rules, two visualization tools based on boxplots and density plots were implemented. A network visualization tool is also provided to rapidly check interactions of every feature condition. An additional tool is provided by using a grid of boxplots, where comparison between quartiles of every distribution with a reference is performed. Based on this comparison, an extrapolation of counterfactual examples to regression was also implemented. A set of examples is described, including a setting where regression models performance is compared in detail using EDRs. Specifically, the error difference between two models in a dataset is studied by deriving rules highlighting regions of the input space where model performance difference is unexpected. The application of visual tools is illustrated using EDRs examples derived from public available datasets. Also, case studies illustrating the specialization of subgroups, identification of counter factual subgroups and detecting unanticipated complex models are presented. This paper extends the state of the art by providing a method to derive explanations for model performance instead of explanations for model predictions.
2023
Authors
Fernandes, S; Fanaee T, H; Gama, J; Tisljaric, L; Smuc, T;
Publication
MACHINE LEARNING
Abstract
Densification events in time-evolving networks refer to instants in which the network density, that is, the number of edges, is substantially larger than in the remaining. These events can occur at a global level, involving the majority of the nodes in the network, or at a local level involving only a subset of nodes.While global densification events affect the overall structure of the network, the same does not hold in local densification events, which may remain undetectable by the existing detection methods. In order to address this issue, we propose WINdowed TENsor decomposition for Densification Event Detection (WINTENDED) for the detection and characterization of both global and local densification events. Our method combines a sliding window decomposition with statistical tools to capture the local dynamics of the network and automatically find the irregular behaviours. According to our experimental evaluation, WINTENDED is able to spot global densification events at least as accurately as its competitors, while also being able to find local densification events, on the contrary to its competitors.
2023
Authors
Braguez, J; Braguez, M; Moreira, S; Filipe, C;
Publication
Procedia Computer Science
Abstract
2023
Authors
Albuquerque, C; Correia, FF;
Publication
EuroPLoP
Abstract
Monitoring a system over time is as important as ever with the increasing use of cloud-native software architectures. This paper expands the set of patterns published in a previous paper (Liveness Endpoint, Readiness Endpoint and Synthetic Testing) with two solutions for supporting teams in diagnosing occurring issues — Deployment Tracking and Exception Tracking. These patterns advise tracking relevant events that occur in the system. The Deployment Tracking pattern provides means to limit the sources of an anomaly, and the Exception Tracking pattern makes a specific class of anomalies visible so that a team can act on them. Both patterns help practitioners identify the root cause of an issue, which is instrumental in fixing it. They can help even less experienced professionals to improve monitoring processes, and reduce the mean time to resolve problems with their application. These patterns draw on documented industry best practices and existing tools. In order to help the reader find other patterns that supplement the ones suggested in this study, relations to already-existing monitoring patterns are also examined.
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