2023
Autores
Mateus, F; Santos, AS; Brito, MF; Madureira, AM;
Publicação
Lecture Notes in Networks and Systems
Abstract
The transport and logistics sector, which include freight forwarders companies, constitutes a vast network of entities that are central to a good performance in services. With the COVID-19 pandemic and its effects on the global economy, there was a huge shortage in the number of containers available, thus creating the need to optimize the loading of available equipment to avoid waste and maximize profits from each export. The present work presents a novel approach where a set of restrictions were created that, applied in synergy with the Non-Linear GRG algorithm, aim to allocate the boxes in different consecutive lines until forming a wall, and, therefore, the walls complete the container, in order to maximize the occupancy on it. To validate the proposed approach a prototype was developed and studied in real-world problem where the solutions resulted in occupations around 80% to 90%. Thus, we can foresee the importance of the proposed approach in decision-making regarding container consolidation services. © 2023, The Author(s), under exclusive license to Springer Nature Switzerland AG.
2023
Autores
Iria, J; Scott, P; Attarha, A; Soares, F;
Publicação
SUSTAINABLE ENERGY GRIDS & NETWORKS
Abstract
Aggregators are acknowledged as key agents to enable the active participation of household and commercial distributed energy resources (DER) in electricity markets. In recent years, many researchers and practitioners have been working on the development of diverse network-secure and network-insecure bidding strategies to support the participation of DER aggregators in electricity markets. An example of this is the extensive work developed by the authors of this paper in various R&D projects with industry. This paper builds on the experience gained in previous works and its main contribution is a thorough comparison between these strategies, resulting in an extensive discussion of their pros and cons. The discussion compares the economic and network security performance of the strategies, as well as their communication, computational, and data privacy requirements. To discuss and quantify these aspects, we formulate, implement, and test various bidding strategies on a real-world MV-LV distribution network with 2 aggregators and 522 customers for multiple DER scenarios. The discussion of the results provides realistic and valuable information on the pros and cons of each strategy, helping energy system stakeholders to understand which strategy may better fit their needs.
2023
Autores
Baptista, MC; Gomes, BM; Capela, D; Ferreira, MFS; Guimaraes, D; Silva, NA; Jorge, PAS; Silva, JJ; Braga, MH;
Publicação
BATTERIES-BASEL
Abstract
Anode-less batteries are a promising innovation in energy storage technology, eliminating the need for traditional anodes and offering potential improvements in efficiency and capacity. Here, we have fabricated and tested two types of anode-less pouch cells, the first using solely a copper negative current collector and the other the same current collector but coated with a nucleation seed ZnO layer. Both types of cells used the same all-solid-state electrolyte, Li2.99Ba0.005ClO composite, in a cellulose matrix and a LiFePO4 cathode. Direct and indirect methods confirmed Li metal anode plating after charging the cells. The direct methods are X-ray photoelectron spectroscopy (XPS) and laser-induced breakdown spectroscopy (LIBS), a technique not divulged in the battery world but friendly to study the surface of the negative current collector, as it detects lithium. The indirect methods used were electrochemical cycling and impedance and scanning electron microscopy (SEM). It became evident the presence of plated Li on the surface of the current collector in contact with the electrolyte upon charging, both directly and indirectly. A maximum average lithium plating thickness of 2.9 mu m was charged, and 0.13 mu m was discharged. The discharge initiates from a maximum potential of 3.2 V, solely possible if an anode-like high chemical potential phase, such as Li, would form while plating. Although the ratings and energy densities are minor in this study, it was concluded that a layer of ZnO, even at 25 degrees C, allows for higher discharge power for more hours than plain Cu. It was observed that where Li plates on ZnO, Zn is not detected or barely detected by XPS. The present anode-less cells discharge quickly initially at higher potentials but may hold a discharge potential for many hours, likely due to the ferroelectric character of the electrolyte.
2023
Autores
Oliveira, LM; Meglinski, I; Tuchin, VV;
Publicação
JOURNAL OF BIOPHOTONICS
Abstract
[No abstract available]
2023
Autores
Almeida, JB; Barbosa, M; Barthe, G; Grégoire, B; Laporte, V; Léchenet, JC; Oliveira, T; Pacheco, H; Quaresma, M; Schwabe, P; Séré, A; Strub, PY;
Publicação
IACR Trans. Cryptogr. Hardw. Embed. Syst.
Abstract
In this paper we present the first formally verified implementations of Kyber and, to the best of our knowledge, the first such implementations of any post-quantum cryptosystem. We give a (readable) formal specification of Kyber in the EasyCrypt proof assistant, which is syntactically very close to the pseudocode description of the scheme as given in the most recent version of the NIST submission. We present high-assurance open-source implementations of Kyber written in the Jasmin language, along with machine-checked proofs that they are functionally correct with respect to the EasyCrypt specification. We describe a number of improvements to the EasyCrypt and Jasmin frameworks that were needed for this implementation and verification effort, and we present detailed benchmarks of our implementations, showing that our code achieves performance close to existing hand-optimized implementations in C and assembly.
2023
Autores
Ibarra, CHV; de Faria, DLC; Endo, AT; Beder, DM; Vincenzi, AMR;
Publicação
PROCEEDINGS OF THE 19TH BRAZILIAN SYMPOSIUM ON INFORMATION SYSTEMS
Abstract
Context: Mock objects are commonly used in unit tests to isolate a class from its dependencies by substituting a dependency class instead of the original. Problem: However, in addition to the use of mock objects in the vast majority of OO applications, there are some discrepancies in their use. Solution: This work aims to present a case study of an industry application regarding the use of mock objects. The application in question is part of a private flight management system. IS Theory: We conceived this work based on the General Systems Theory, specifically to evaluate a microservicebased system’s use of testing doubles during testing automation. Method: In the analyzed application, mock object implementations are highly related to the system design. For example, the number of dependencies in a production class is directly related to the number of mocks in the respective test class. As a consequence, poor design choices are harmful to intrinsic quality factors such as the maintainability of the application tests. Our study uses metrics to analyze this practice. The research will consider factors of this system, aiming mainly to contribute to the improvement of test doubles by the test team. Summary of Results: Application of simulated objects in a similar system indicates that developers are making immature use of the technique, possibly due to system design problems. This study concludes that theory and practice are misaligned. Contributions and Impact in the IS area: The main contribution is to indicate points to improving software testing practice by using mocks correctly.
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