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Protecting the Ccsds 123.0-B-2 Compression Algorithm Against Single-Event Upsets for Space Applications

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SSRN

SSRN 2024年

作者： Báscones, Daniel García-Herrero, Francisco Ruano, Óscar González, Carlos Mozos, Daniel Maestro, Juan Antonio Department of Computer Architecture and Automatics UCM Profesor García Santesmases 9 Madrid28040 Spain

Hyperspectral imaging is an excellent tool to remotely analyse the Earth fromin-orbit devices. Satellites capture these images containing vast informationabout the ground pixels. To optimise storage and transmission speeds, com-pression is often performed onboard the satellite. To that end, algorithmssuch as the CCSDS 123.0-B-2 are implemented on FPGAs, enabling thisprocess in an efficient and fast manner. Single-Event Upsets (SEU) are com-monplace in this scenario: bit-flips in the FPGA’s configuration memorywhich can catastrophically alter the algorithm’s output. In this paper, wepropose a fault tolerance technique for this specific case. The compressioncore is checked periodically by running a golden model designed to excite thefull internal datapath based on a synthetic image. A failure in this checkwill trigger a reconfiguration of the compression core. Results show betterdetection rates than Dual Modular Redundancy (DMR) at a fraction of theresource cost, proving this technique as a viable alternative. Furthermore,other algorithms with similar processing flows might benefit as well from thistechnique. © 2024, The Authors. All rights reserved.

关键词： Field programmable gate arrays (FPGA)

Project-Based Learning with historic buildings: immersion in real training environments for the Degree in Technical architecture

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Project-Based Learning with historic buildings: immersion in...

2021 International Conference of Innovation, Learning and Cooperation, CINAIC 2021

作者： Valentín-Gamazo, David Villanueva Durango, Nelson Tuesta García-Herrero, Francisco Blanco, Ma Isabel Mansilla de las Moras, Ma Cruz Rey Technical Teaching Department European University Miguel de Cervantes Valladolid Spain Department of Computer Architecture and Automatics Computer Science Faculty Complutense University of Madrid Madrid Spain Humanities Department European University Miguel de Cervantes Valladolid Spain

University education in the knowledge branches of Engineering and architecture, has usually been based on the system of assignments and projects as a practical dynamic of training and assessment in many subjects. With the EHEA arrival, the search for new complementary systems more focused on learning than on teaching or, in other words, on the student than on the teacher, boosted the commitment to the methodology known as Project Based Learning (PBL), oriented to the development of technical skills in contexts similar to those produced in professional environments. In general, these pedagogical scenarios are built on the basis of theoretical models inspired by real cases to a greater or lesser extent. This paper analyzes the method implemented since the 2017-2018 academic year to innovate in the compulsory subject of Rehabilitation, Restoration and Pathology of the Technical architecture Degree at the European University Miguel de Cervantes, when the PBL applied in case studies of existing historic buildings;providing students with heritage constructions to visit, recognize, measure, diagnose, draw, rehabilitate, restore, etc., and allowing their immersion in situations that introduce them to their future work practice reality. Copyright © 2021 for this paper by its authors. Use permitted under Creative Commons License Attribution 4.0 International (CC BY 4.0).

关键词： Students

Learning Difference Equations with Structured Grammatical Evolution for Postprandial Glycaemia Prediction

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arXiv 2023年

作者： Parra, Daniel Joedicke, David Velasco, J. Manuel Kronberger, Gabriel Hidalgo, J. Ignacio Department of Computer Architecture and Automatics Universidad Complutense de Madrid Madrid Spain University of Applied Sciences of Upper Austria Hagenberg Austria

People with diabetes must carefully monitor their blood glucose levels, especially after eating. Blood glucose regulation requires a proper combination of food intake and insulin boluses. Glucose prediction is vital to avoid dangerous post-meal complications in treating individuals with diabetes. Although traditional methods, such as artificial neural networks, have shown high accuracy rates, sometimes they are not suitable for developing personalised treatments by physicians due to their lack of interpretability. In this study, we propose a novel glucose prediction method emphasising interpretability: Interpretable Sparse Identification by Grammatical Evolution. Combined with a previous clustering stage, our approach provides finite difference equations to predict postprandial glucose levels up to two hours after meals. We divide the dataset into four-hour segments and perform clustering based on blood glucose values for the two-hour window before the meal. Prediction models are trained for each cluster for the two-hour windows after meals, allowing predictions in 15-minute steps, yielding up to eight predictions at different time horizons. Prediction safety was evaluated based on Parkes Error Grid regions. Our technique produces safe predictions through explainable expressions, avoiding zones D (0.2% average) and E (0%) and reducing predictions on zone C (6.2%). In addition, our proposal has slightly better accuracy than other techniques, including sparse identification of non-linear dynamics and artificial neural networks. The results demonstrate that our proposal provides interpretable solutions without sacrificing prediction accuracy, offering a promising approach to glucose prediction in diabetes management that balances accuracy, interpretability, and computational efficiency. © 2023, CC BY-NC-ND.

关键词： Forecasting

Low-Complexity Linear Programming Based Decoding of Quantum LDPC Codes

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Low-Complexity Linear Programming Based Decoding of Quantum ...

IEEE International Conference on Communications (ICC)

作者： Sana Javed Francisco Garcia-Herrero Bane Vasić Mark F. Flanagan School of Electrical and Electronic Engineering University College Dublin Belfield Dublin 4 Ireland Department of Computer Architecture and Automatics Complutense University of Madrid Madrid Spain Department of Electrical and Computer Engineering The University of Arizona Tucson AZ USA

ISBN: (数字)9781728190549

ISBN: (纸本)9781728190556

This paper proposes two approaches for reducing the impact of the error floor phenomenon when decoding quantum low-density parity-check codes with belief propagation based algorithms. First, a low-complexity syndrome-based linear programming (SB- LP) decoding algorithm is proposed, and second, the proposed SB-LP is applied as a post-processing step after syndrome-based min-sum (SB-MS) decoding. For the latter case, a new early stopping criterion is introduced to decide when to activate the SB- LP algorithm, avoiding executing a predefined maximum number of iterations for the SB-MS decoder. Simulation results show, for a sample hypergraph code, that the proposed decoder can lower the error floor by two to three orders of magnitude compared to SB-MS for the same total number of decoding iterations.

关键词： Error analysis Simulation Programming Linear programming Decoding Hamming distances Iterative decoding

Low-Complexity Linear Programming Based Decoding of Quantum LDPC codes

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arXiv 2023年

作者： Javed, Sana Garcia-Herrero, Francisco Vasić, Bane Flanagan, Mark F. School of Electrical and Electronic Engineering University College Dublin Belfield Dublin Ireland Department of Computer Architecture and Automatics Complutense University of Madrid Madrid Spain Department of Electrical and Computer Engineering The University of Arizona TucsonAZ85721 United States

This paper proposes two approaches for reducing the impact of the error floor phenomenon when decoding quantum low-density parity-check codes with belief propagation based algorithms. First, a low-complexity syndrome-based linear programming (SB-LP) decoding algorithm is proposed, and second, the proposed SB-LP is applied as a post-processing step after syndrome-based min-sum (SB-MS) decoding. For the latter case, a new early stopping criterion is introduced to decide when to activate the SB-LP algorithm, avoiding executing a predefined maximum number of iterations for the SB-MS decoder. Simulation results show, for a sample hypergraph code, that the proposed decoder can lower the error floor by two to three orders of magnitude compared to SB-MS for the same total number of decoding iterations. © 2023, CC BY.

关键词： Belief propagation

Diversity Methods for Improving Convergence and Accuracy of Quantum Error Correction Decoders Through Hardware Emulation

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arXiv 2025年

作者： Garcia-Herrero, Francisco Valls, Javier Vergara-Picazo, Llanos Torres, Vicente Department of Computer Architecture and Automatics Complutense University of Madrid Madrid Spain Instituto de Telecomunicaciones y Aplicaciones Multimedia Universitat Politecnica de Valencia Valencia Spain

Understanding the impact of accuracy and speed when quantum error correction (QEC) decoders transition from floating-point software implementations to finite-precision hardware architectures is crucial for resource estimation on both classical and quantum sides. The final performance of the hardware implementation influences the code distance, affecting the number of physical qubits needed, and defines connectivity between quantum and classical control units, among other factors like refrigeration systems. This paper introduces a hardware emulator to evaluate QEC decoders using real hardware instead of software models. The emulator can explore 1013 different error patterns in 20 days with a single FPGA device running at 150 MHz, guaranteeing the decoder’s performance at logical rates of 10−12, the requirement for most quantum algorithms. In contrast, an optimized C++ software on an Intel Core i9 with 128 GB RAM would take over a year to achieve similar results. The emulator also enables storing patterns that generate logical errors for offline analysis and to design new decoders. Using results from the emulator, we propose a diversity-based method combining several belief propagation (BP) decoders with different quantization levels. Individually, these decoders may show sub-par error correction, but together they outperform the floating-point version of BP for quantum low-density parity-check (QLDPC) codes like hypergraph or lifted product. Preliminary results with circuit-level noise and bivariate bicycle codes suggest hardware insights can also improve software. Our diversity-based proposal achieves a similar logical error rate as BP with ordered statistics decoding, with average speed improvements ranging from 30% to 80%, and 10% to 120% in worst-case scenarios, while reducing post-processing algorithm activation by 47% to 96.93%, maintaining the same accuracy. © 2025, CC BY.

关键词： Qubits

Layered Decoding of Quantum LDPC Codes

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Layered Decoding of Quantum LDPC Codes

Topics in Coding (ISTC), International Symposium on

作者： Julien Du Crest Francisco Garcia-Herrero Mehdi Mhalla Valentin Savin Javier Valls Univ. Grenoble Alpes Grenoble INP LIG Grenoble France Department of Computer Architecture and Automatics (DACYA) Complutense University of Madrid Spain Univ. Grenoble Alpes CNRS Grenoble INP LIG Grenoble France Univ. Grenoble Alpes CEA-Léti Grenoble France Instituto de Telecomunicaciones y Aplicaciones Multimedia Universitat Politecnica de Valencia Valencia Spain

We address the problem of doing message passing based decoding of quantum LDPC codes under hardware latency limitations. We propose a novel way to do layered decoding that suits quantum constraints and outperforms flooded scheduling, the usual scheduling on parallel architectures. A generic construction is given to construct layers of hypergraph product codes. In the process, we introduce two new notions, t-covering layers which is a generalization of the usual layer decomposition, and a modified scheduling called random order scheduling. Numerical simulations show that the random ordering is of independent interest as it helps relieve the high error floor typical of message passing decoders on quantum codes for both layered and serial decoding without the need of post-processing.

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Check-Agnosia based Post-Processor for Message-Passing Decoding of Quantum LDPC Codes

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arXiv 2023年

作者： Crest, Julien du Garcia-Herrero, Francisco Mhalla, Mehdi Savin, Valentin Valls, Javier Université Grenoble Alpes Grenoble INP LIG GrenobleF-38000 France Department of Computer Architecture and Automatics Complutense University of Madrid Madrid Spain Université Grenoble Alpes CNRS Grenoble INP LIG GrenobleF-38000 France Université Grenoble Alpes CEA-Léti GrenobleF-38054 France Instituto de Telecomunicaciones y Aplicaciones Multimedia Universitat Politecnica de Valencia Valencia Spain

The inherent degeneracy of quantum low-density parity-check codes poses a challenge to their decoding, as it significantly degrades the error-correction performance of classical message-passing decoders. To improve their performance, a post-processing algorithm is usually employed. To narrow the gap between algorithmic solutions and hardware limitations, we introduce a new post-processing algorithm with a hardware-friendly orientation, providing error correction performance competitive to the state-of-the-art techniques. The proposed post-processing, referred to as check-agnosia, is inspired by stabilizer-inactivation, while considerably reducing the required hardware resources, and providing enough flexibility to allow different message-passing schedules and hardware architectures. We carry out a detailed analysis for a set of Pareto architectures with different tradeoffs between latency and power consumption, derived from the results of implemented designs on an FPGA board. We show that latency values close to one microsecond can be obtained on the FPGA board, and provide evidence that much lower latency values can be obtained for ASIC implementations. In the process, we also demonstrate the practical implications of the recently introduced t-covering layers and random-order layered scheduling. © 2023, CC BY.

关键词： Error correction

A Novel Method for Wind Power Plants’ Repowering Based on Multi-Criteria Decision-Making

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SSRN

SSRN 2023年

作者： Gil García, Isabel C. Fernández-Guillamón, Ana García-Cascales, M. Socorro Molina-García, Ángel c/ Coruña km 38500 Collado Villalba Madrid28400 Spain Dept. of Applied Mechanics and Projects Engineering - E.T.S. de Ingenieros Industriales & Renewable Energy Research Institute Universidad de Castilla-La Mancha C/ De la Investigación S/N Albacete02006 Spain Department of Electronics Computer Architecture and Project Engineering Department of Automatics Electrical Engineering and Electronic Technology Universidad Politécnica de Cartagena Campus Muralla del Mar Murcia Cartagena30202 Spain

Due to the climate change, over the last decades there have been changes in the rhythm of nature. However, there is an increasing social consciousness regarding decarbonization, and governments include new policies and economic support measures for renewables. The participation of the onshore and offshore wind sectors play a central role in this scenario, expecting that more than 6000 GW will be globally installed in 2050. However, the useful life of many wind power plants is coming to their end, and thus, some countries will face in the coming years the decision of repowering, decommissioning, installing new turbines, or a combination of them. In general, such areas with the greatest wind potential are already occupied by relatively old wind turbines. Subsequently, a complex group of factors influences on the best solution decision-making: climatic, technological, environmental, social or economic. This paper proposes an optimized methodology based on multi-criteria decision-making to estimate the most appropriate solution for extending the useful-life of wind power plants. The methodology is divided into three stages: (i) data, (ii) alternatives and (iii) optimization. It was assessed with a Spanish onshore wind power plant connected to the grid. From the initial data, 11 alternatives were designed based on 10 selection factors. The results provide an optimal solution, combining both repowering and installation of new wind turbines. It would allow us to reduce the LCOE of the new wind plants installed in the European Union by more than 50%. © 2023, The Authors. All rights reserved.

关键词： Wind turbines