Cookies Policy
The website need some cookies and similar means to function. If you permit us, we will use those means to collect data on your visits for aggregated statistics to improve our service. Find out More
Accept Reject
  • Menu
Publications

2020

Modeling frequency response dynamics in power system scheduling

Authors
Zhang, ZY; Du, ES; Zhu, GP; Zhang, N; Kang, CQ; Qian, MH; Catalao, JPS;

Publication
ELECTRIC POWER SYSTEMS RESEARCH

Abstract
Since wind turbines or photovoltaic (PV) panels are generally connected to the power grid by power electronic inverters, the power system inertia is gradually decreasing along with the growing share of renewable energy. This jeopardizes the system frequency response dynamics so that the corresponding frequency security issue is becoming the bottle-neck factor that restricts the development of high renewable energy penetration. Consequently, power system scheduling models need to incorporate frequency dynamics. The difficulty lies in how to formulate the frequency security constraints from the perspective of hourly load-generation balance since the frequency dynamics have a shorter time scale (5 similar to 30 s). Several modeling methods have been proposed based on different assumptions and simplifications. However, their accuracy is not clear. We first propose a novel method to formulate linear frequency security constraints, which considers more details of frequency response dynamics. Then, an evaluation methodology is designed to quantify the accuracy of those frequency constraints. Using this evaluation method, we compare two typical methods in recent literature with the proposed method. The results show the effectiveness and superiority of our proposed method.

2020

A Computational Model of Tonal Tension Profile of Chord Progressions in the Tonal Interval Space

Authors
Navarro Cáceres, M; Caetano, M; Bernardes, G; Sánchez Barba, M; Sánchez Jara, JM;

Publication
ENTROPY

Abstract
In tonal music, musical tension is strongly associated with musical expression, particularly with expectations and emotions. Most listeners are able to perceive musical tension subjectively, yet musical tension is difficult to be measured objectively, as it is connected with musical parameters such as rhythm, dynamics, melody, harmony, and timbre. Musical tension specifically associated with melodic and harmonic motion is called tonal tension. In this article, we are interested in perceived changes of tonal tension over time for chord progressions, dubbed tonal tension profiles. We propose an objective measure capable of capturing tension profile according to different tonal music parameters, namely, tonal distance, dissonance, voice leading, and hierarchical tension. We performed two experiments to validate the proposed model of tonal tension profile and compared against Lerdahl's model and MorpheuS across 12 chord progressions. Our results show that the considered four tonal parameters contribute differently to the perception of tonal tension. In our model, their relative importance adopts the following weights, summing to unity: dissonance (0.402), hierarchical tension (0.246), tonal distance (0.202), and voice leading (0.193). The assumption that listeners perceive global changes in tonal tension as prototypical profiles is strongly suggested in our results, which outperform the state-of-the-art models.

2020

Interpretable and Annotation-Efficient Learning for Medical Image Computing - Third International Workshop, iMIMIC 2020, Second International Workshop, MIL3ID 2020, and 5th International Workshop, LABELS 2020, Held in Conjunction with MICCAI 2020, Lima, Peru, October 4-8, 2020, Proceedings

Authors
Cardoso, JS; Nguyen, HV; Heller, N; Abreu, PH; Isgum, I; Silva, W; Cruz, RPM; Amorim, JP; Patel, V; Roysam, B; Zhou, SK; Jiang, SB; Le, N; Luu, K; Sznitman, R; Cheplygina, V; Mateus, D; Trucco, E; Sureshjani, SA;

Publication
iMIMIC/MIL3ID/LABELS@MICCAI

Abstract

2020

Agricultural sustainability assessment using multicriteria indicators and hierarchical tools-a review

Authors
Neto, J; Cunha, M;

Publication
INTERNATIONAL JOURNAL OF SUSTAINABLE AGRICULTURAL MANAGEMENT AND INFORMATICS

Abstract
Europe's 2020 strategy considers sustainable management as an increasingly important criterion for the several normative and incentives recently legislated. It is expectable that in short-term, political decision-makers and farmers will need to evaluate the type and degree of their activities' impact on the environment, economy and society. For this reason, tools are required to ease and translate these evaluations, capable of defining the main imbalance factors that need action. Despite a wide range of sustainability assessment tools available in the literature, the underlying methodologies are very similar and resort to indicators aggregated in hierarchical evaluation models that should be representative and adaptive for putative transferability. This paper provides an overview of the most relevant computational sustainability evaluation tools and their scope of application, in a benchmarking analysis. To ease the comprehension of these tools, a literature review was performed to analyse their structural elements and based on methodologies. Copyright © 2020 Inderscience Enterprises Ltd.

2020

Automated Development of Custom Fall Detectors: Position, Model and Rate Impact in Performance

Authors
Silva, J; Gomes, D; Sousa, I; Cardoso, JS;

Publication
IEEE SENSORS JOURNAL

Abstract
The past years have witnessed a boost in fall detection-related research works, disclosing an extensive number of methodologies built upon similar principles but addressing particular use-cases. These use-cases frequently motivate algorithm fine-tuning, making the modelling stage a time and effort consuming process. This work contributes towards understanding the impact of several of the most frequent requirements for wearable-based fall detection solutions in their performance (usage positions, learning model, rate). We introduce a new machine learning pipeline, trained with a proprietary dataset, with a customisable modelling stage which enabled the assessment of performance over each combination of custom parameters. Finally, we benchmark a model deployed by our framework using the UMAFall dataset, achieving state-of-the-art results with an F1-score of 84.6% for the classification of the entire dataset, which included an unseen usage position (ankle), considering a sampling rate of 10 Hz and a Random Forest classifier.

2020

RAMBLE: Opportunistic Crowdsourcing of User-Generated Data using Mobile Edge Clouds

Authors
Garcia, M; Rodrigues, J; Silva, J; Marques, ERB; Lopes, LMB;

Publication
2020 FIFTH INTERNATIONAL CONFERENCE ON FOG AND MOBILE EDGE COMPUTING (FMEC)

Abstract
We present RAMBLE(1), a framework for georeferenced content-sharing in environments that have limited infrastructural communications, as is the case for rescue operations in the aftermath of natural disasters. RAMBLE makes use of mobile edge-clouds, networks formed by mobile devices in close proximity, and lightweight cloudlets that serve a small geographical area. Using an Android app, users ramble whilst generating geo-referenced content (e.g., text messages, sensor readings, photos, or videos), and disseminate that content opportunistically to nearby devices, cloudlets, or even cloud servers, as allowed by intermittent wireless connections. Each RAMBLE-enabled device can both produce information; consume information for which it expresses interest to neighboors, and; serve as an opportunistic cache for other devices. We describe the architecture of the framework and a case-study application scenario we designed to evaluate its behavior and performance. The results obtained reinforce our view that kits of RAMBLE-enabled mobile devices and modest cloudlets can constitute lightweight and flexible untethered intelligence gathering platforms for first responders in the aftermath of natural disasters, paving the way for the deployment of humanitary assistance and technical staff at large.

  • 1574
  • 4538