A Model-Based Framework to Assess the Reliability of Safety-Critical Applications

Solutions based on artificial intelligence and brain-inspired computations like Artificial Neural Networks (ANNs) are suited to deal with the growing computational complexity required by state-of-the-art electronic devices. Many applications that are being deployed using these computational models are considered safety-critical (e.g., self-driving cars), producing a pressing need to evaluate their reliability. Besides, state-of-the-art ANNs require significant memory resources to store their parameters (e.g., weights, activation values), which goes outside the possibility of many resource-constrained embedded systems. In this light, Approximate Computing (AxC) has become a significant field of research to improve memory footprint, speed, and energy consumption in embedded and high-performance systems. The use of AxC can significantly reduce the cost of ANN implementations, but it may also reduce the inherent resiliency of this kind of application. On this scope, reliability assessments are carried out by performing fault injection test campaigns. The intent of the paper is to propose a framework that, relying on the results of radiation tests in Commercial-Off-The-Shelf (COTS) devices, is able to assess the reliability of a given application. To this end, a set of different radiation-induced errors in COTS memories is presented. Upon these, specific fault models are extracted to drive emulation-based fault injections

A contribution to the in-orbit validation of a radiation-hardened communication platform to be used in small satellites

Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro Tecnológico, Programa de Pós-Graduação em Engenharia Elétrica, Florianópolis, 2019.Durante a última década, o número de missões espaciais utilizando nanossatélites aumentou consideravelmente devido a utilização do padrão CubeSat. O padrão CubeSat trouxe uma opção viável tanto para a comunidade acadêmica quanto para as empresas, uma vez que traz um orçamento consideravelmente reduzido quando comparado a modelos desenvolvidos por grandes corporações. Entretanto, diferentes protocolos de comunicações são empregados, diminuindo a integração entre as missões espaciais. Contudo, os protocolos definidos pelo CCSDS surgem como uma forte alternativa para quebrar essa barreira de integração, uma vez que já foram utilizados em mais de 900 missões espaciais. Com isso, este trabalho descreve o desenvolvimento de um módulo de comunicação para nanossatélites seguindo as recomendações propostas pelo CCSDS. Este trabalho tem como dispositivo alvo um novo FPGA endurecido contra os efeitos da radiação (radiation- hardened). Esse FPGA foi desenvolvido por uma companhia francesa e tem um grande potencial de utilização em novas missões espaciais devido ao fato de não ter as restrições provindas das regulamentações ITAR e EAR. Para alcançar os objetivos, o trabalho faz uso de uma unidade de telemetria e telecomandos e desenvolve uma arquitetura para um OBDH com o propósito de validar os telecomandos recebidos e gerar telemetria, tanto no aspecto de dados de status quanto para dados científicos. A implementação proposta por este trabalho tem como base a arquitetura do Payload-X, que foi desenvolvido para ser operado como carga útil juntamente com o nanossatélite FloripaSat-I. Testes em hardware-in-the-loop aplicados a casos de usos do sistema mostraram a validade dos fluxos de telecomando e telemetria, sendo também verificadas a alocação de recursos do FPGA pela implementação e a utilização do Static Time Analisys para definir a viabilidade da aplicação.Abstract : During the last decade, the number of space missions using nano-satellites has increased considerably, this is due to the use of the CubeSat standard that has brought a viable option for both the academic community and the companies since it brings a considerably reduced budget when compared to models developed by large corporations. However, different communication protocols are employed, reducing the integration between these space missions. Though, the protocols defined by the CCSDS appear as a strong alternative to break this integration barrier since they have already been used in more than 900 space missions. As a result, this work describes the development of a communication module for nanosatellites following the recommendations proposed by the CCSDS. This work has as its target device a new radiation-hardened FPGA developed by a French company that has a high potential usage in new space missions since it does not have the restrictions coming from the ITAR and EAR regulations. The work makes use of a telemetry unit and remote controls and develops a platform for an OBDH to validate the incoming telecommands and to generate telemetry, both in terms of status data and scientific data. The implementation proposed by this work is based on the Payload-X architecture, which was developed to be used as a payload in the FloripaSat-I nanosatellite. Hardware-in-the-loop tests applied to system use cases showed the validity of telecommand and telemetry flows, as well as the allocation of FPGA resources through implementation and the use of Static Time Analysis to define the feasibility of the application

Analysis of space and atmospheric radiation-induced effects on memory devices

Le rayonnement est défini comme l'émission ou la transmission d'énergie sous forme d'ondes ou de particules, qui peuvent être ionisantes ou non ionisantes. L'interaction entre le rayonnement et la matière peut générer différentes réactions, qui peuvent varier en fonction des propriétés de la particule (type, énergie cinétique, masse et charge) et de la matière ciblée (semi-conducteurs dans le cadre de cette thèse). L'exposition de composants électroniques à des environnements avec une présence significative de rayonnement peut conduire à ce type d'interaction et, par conséquent, à une variété d'effets qui peuvent affecter considérablement la fiabilité des systèmes électroniques.Lors de la conception de dispositifs et de systèmes électroniques, la prise en compte des effets des rayonnements est fondamentale pour les applications dans des environnements hostiles. Par exemple, dans les systèmes avioniques et spatiaux, ces effets sont largement étudiés pour garantir la haute fiabilité des composants et fournir les informations nécessaires pour les décisions de conception. Les préoccupations liées aux rayonnements ont commencé à être prises en compte au début de l'ère spatiale.Les rayonnements ionisants peuvent induire des effets dans différents dispositifs, et plusieurs travaux ont montré que les mémoires électroniques sont l'une des principales causes d’erreur dans les systèmes. De plus, en raison de leur nature, les mémoires ont la capacité intrinsèque de stocker la trace des fautes induites par les rayonnements, comme le Single-Bit Upset (SBU), ce qui fait de ces dispositifs le meilleur candidat pour étudier les événements singuliers.Le premier sujet introduit par la thèse est une étude sur les effets induits par les ions lourds sur une mémoire Flash de type NAND. Cette étude est basée sur plusieurs campagnes d'irradiation avec une large gamme d'énergies. Les résultats ont révélé différents mécanismes de défaillance, notamment des SBUs, des petits groupes d'erreurs, des fautes dans le registre et des fautes affectant une ou plusieurs colonnes de la mémoire. La section efficace a été calculée pour chaque type de faute, et leurs causes ont été discutées.Ensuite, une étude sur les effets de la radiation neutronique (spectres thermiques et atmosphériques) sur une DRAM auto-rafraîchissante est présentée. Des méthodes de test statique et dynamique ont été utilisées pour définir la réponse du dispositif sous faisceau neutronique. Dans ce manuscrit, les résultats expérimentaux de deux campagnes de tests sont présentés, avec l'identification de différents modèles de faute, comme les SBUs, bits collés et blocs d’erreurs. Ces fautes ont été étudiées et caractérisées avec le calcule de la section efficace, du taux d'erreurs et l’étude des bitmaps. Une analyse du temps de rétention des cellules affectées a été réalisée, montrant une différence d’efficacité entre le mécanisme d'autorafraîchissement et une véritable opération de lecture. De plus, une corrélation du mécanisme de défaillance qui génère à la fois des SBUs et des bits collés est également proposée. Finalement, les effets de réparation du recuit à haute température ont été étudiés dans des tests post irradiation.Après, ce manuscrit présente aussi une étude comparative sur les effets induits par les neutrons sur les SDRAM produites avec trois nœuds technologiques différents. Les résultats ont révélé la présence de SBUs et de bits collés dans les mémoires, montrant une sensibilité plus élevée pour la génération la plus ancienne et des résultats similaires pour les deux autres modèles étudiés.Enfin, une procédure est présentée afin d’évaluer la fiabilité des applications basées sur réseau de neurones convolutifs (CNN). Dans cette optique, cette étude propose d'utiliser des modèles de défauts réalistes extraits des tests de rayonnement comme entrée pour un émulateur logiciel qui effectue l'injection de défauts dans le système informatique dans lequel le CNN est implémenté.Radiation is defined as the emission or transmission of energy as waves or particles, which can be either ionizing or non-ionizing. The interaction between the radiation and the matter can generate different reactions, which may vary depending on the properties of the particle (type, kinetic energy, mass, and charge), and the target (semiconductors in this thesis scope). The exposition of electronics components to environments with a significant presence of radiation may lead to this kind of interaction and, consequently, to a variety of effects that can drastically affect the reliability of electronic systems.When designing electronic devices and systems, considering radiation effects is fundamental for applications in harsh environments. For instance, in avionics and space systems, these effects are extensively studied to ensure the high reliability of the components and provide the needed insight for design decisions. The concerns related to radiation started to be noted at the beginning of the space era.Ionizing radiation may induce effects in different types of devices, and many works have shown that memories are one of the highest contributors to soft errors in systems. Furthermore, due to their nature, memories have the intrinsic capability of storing radiation-induced fault tracks, e.g., Single-Bit Upsets (SBUs), making these devices the best candidate for studying soft errors.The first topic introduced by the thesis is a study on the heavy-ion induced effects on a Single-Level Cell NAND Flash. This study is based on several irradiation test campaigns with a wide range of heavy-ions energies. The results revealed different failure mechanisms, including Single-Event Upsets, small clusters of errors, data register upsets, and a column-wise failure mode. Cross section was calculated for each of these failure modes, and their causes were discussed.Then, a study on the effects of neutron irradiation (thermal and atmospheric-like spectra) on a self-refresh DRAM is presented. Static and dynamic test methods were used to define the response of the device under irradiation. In this manuscript, experimental results from two different test campaigns are presented, with the identification of SBUs, stuck bits, and block errors. These faults were investigated and characterized by event cross section, soft-error rates, and bitmaps evaluations. An analysis of the damaged cells' retention time was performed, showing a difference between the self-refresh mechanism and a read operation. Additionally, a correlation of the fault mechanism that generates both SBUs and stuck bits under neutron irradiation is also proposed. Furthermore, high-temperature annealing was studied in post-radiation tests.Following, this thesis presents a comparative study on the neutron-induced effects on SDRAMs produced with three different technology nodes. The results revealed the occurrence of SBUs and stuck-bits in the memories, showing higher sensitivity for the oldest generation and similar results for the other two models.Finally, a framework is presented to assess the reliability of Convolutional Neural Network (CNN) applications. In this light, this study proposes using realistic fault models retrieved from radiation tests as input for a software emulator that performs fault injection in the computing system in which the CNN is implemented

Étude des effets induits par la radiation spatial et atmosphérique sur des mémoires électroniques

Radiation is defined as the emission or transmission of energy as waves or particles, which can be either ionizing or non-ionizing. The interaction between the radiation and the matter can generate different reactions, which may vary depending on the properties of the particle (type, kinetic energy, mass, and charge), and the target (semiconductors in this thesis scope). The exposition of electronics components to environments with a significant presence of radiation may lead to this kind of interaction and, consequently, to a variety of effects that can drastically affect the reliability of electronic systems.When designing electronic devices and systems, considering radiation effects is fundamental for applications in harsh environments. For instance, in avionics and space systems, these effects are extensively studied to ensure the high reliability of the components and provide the needed insight for design decisions. The concerns related to radiation started to be noted at the beginning of the space era.Ionizing radiation may induce effects in different types of devices, and many works have shown that memories are one of the highest contributors to soft errors in systems. Furthermore, due to their nature, memories have the intrinsic capability of storing radiation-induced fault tracks, e.g., Single-Bit Upsets (SBUs), making these devices the best candidate for studying soft errors.The first topic introduced by the thesis is a study on the heavy-ion induced effects on a Single-Level Cell NAND Flash. This study is based on several irradiation test campaigns with a wide range of heavy-ions energies. The results revealed different failure mechanisms, including Single-Event Upsets, small clusters of errors, data register upsets, and a column-wise failure mode. Cross section was calculated for each of these failure modes, and their causes were discussed.Then, a study on the effects of neutron irradiation (thermal and atmospheric-like spectra) on a self-refresh DRAM is presented. Static and dynamic test methods were used to define the response of the device under irradiation. In this manuscript, experimental results from two different test campaigns are presented, with the identification of SBUs, stuck bits, and block errors. These faults were investigated and characterized by event cross section, soft-error rates, and bitmaps evaluations. An analysis of the damaged cells' retention time was performed, showing a difference between the self-refresh mechanism and a read operation. Additionally, a correlation of the fault mechanism that generates both SBUs and stuck bits under neutron irradiation is also proposed. Furthermore, high-temperature annealing was studied in post-radiation tests.Following, this thesis presents a comparative study on the neutron-induced effects on SDRAMs produced with three different technology nodes. The results revealed the occurrence of SBUs and stuck-bits in the memories, showing higher sensitivity for the oldest generation and similar results for the other two models.Finally, a framework is presented to assess the reliability of Convolutional Neural Network (CNN) applications. In this light, this study proposes using realistic fault models retrieved from radiation tests as input for a software emulator that performs fault injection in the computing system in which the CNN is implemented.Le rayonnement est défini comme l'émission ou la transmission d'énergie sous forme d'ondes ou de particules, qui peuvent être ionisantes ou non ionisantes. L'interaction entre le rayonnement et la matière peut générer différentes réactions, qui peuvent varier en fonction des propriétés de la particule (type, énergie cinétique, masse et charge) et de la matière ciblée (semi-conducteurs dans le cadre de cette thèse). L'exposition de composants électroniques à des environnements avec une présence significative de rayonnement peut conduire à ce type d'interaction et, par conséquent, à une variété d'effets qui peuvent affecter considérablement la fiabilité des systèmes électroniques.Lors de la conception de dispositifs et de systèmes électroniques, la prise en compte des effets des rayonnements est fondamentale pour les applications dans des environnements hostiles. Par exemple, dans les systèmes avioniques et spatiaux, ces effets sont largement étudiés pour garantir la haute fiabilité des composants et fournir les informations nécessaires pour les décisions de conception. Les préoccupations liées aux rayonnements ont commencé à être prises en compte au début de l'ère spatiale.Les rayonnements ionisants peuvent induire des effets dans différents dispositifs, et plusieurs travaux ont montré que les mémoires électroniques sont l'une des principales causes d’erreur dans les systèmes. De plus, en raison de leur nature, les mémoires ont la capacité intrinsèque de stocker la trace des fautes induites par les rayonnements, comme le Single-Bit Upset (SBU), ce qui fait de ces dispositifs le meilleur candidat pour étudier les événements singuliers.Le premier sujet introduit par la thèse est une étude sur les effets induits par les ions lourds sur une mémoire Flash de type NAND. Cette étude est basée sur plusieurs campagnes d'irradiation avec une large gamme d'énergies. Les résultats ont révélé différents mécanismes de défaillance, notamment des SBUs, des petits groupes d'erreurs, des fautes dans le registre et des fautes affectant une ou plusieurs colonnes de la mémoire. La section efficace a été calculée pour chaque type de faute, et leurs causes ont été discutées.Ensuite, une étude sur les effets de la radiation neutronique (spectres thermiques et atmosphériques) sur une DRAM auto-rafraîchissante est présentée. Des méthodes de test statique et dynamique ont été utilisées pour définir la réponse du dispositif sous faisceau neutronique. Dans ce manuscrit, les résultats expérimentaux de deux campagnes de tests sont présentés, avec l'identification de différents modèles de faute, comme les SBUs, bits collés et blocs d’erreurs. Ces fautes ont été étudiées et caractérisées avec le calcule de la section efficace, du taux d'erreurs et l’étude des bitmaps. Une analyse du temps de rétention des cellules affectées a été réalisée, montrant une différence d’efficacité entre le mécanisme d'autorafraîchissement et une véritable opération de lecture. De plus, une corrélation du mécanisme de défaillance qui génère à la fois des SBUs et des bits collés est également proposée. Finalement, les effets de réparation du recuit à haute température ont été étudiés dans des tests post irradiation.Après, ce manuscrit présente aussi une étude comparative sur les effets induits par les neutrons sur les SDRAM produites avec trois nœuds technologiques différents. Les résultats ont révélé la présence de SBUs et de bits collés dans les mémoires, montrant une sensibilité plus élevée pour la génération la plus ancienne et des résultats similaires pour les deux autres modèles étudiés.Enfin, une procédure est présentée afin d’évaluer la fiabilité des applications basées sur réseau de neurones convolutifs (CNN). Dans cette optique, cette étude propose d'utiliser des modèles de défauts réalistes extraits des tests de rayonnement comme entrée pour un émulateur logiciel qui effectue l'injection de défauts dans le système informatique dans lequel le CNN est implémenté

SP3 - Impact of Atmospheric and Space Radiation on Sensitive Electronic Devices

Studying the radiation effects on electronic devices is essential for avionics and space systems. The shrinking technology nodes and increasing density of devices enhance the sensitivity of electronic systems to ionizing radiation. Due to their crucial role, memories and processors are the highest contributors to soft errors in systems, making them the best candidates for studying these effects. This work introduces the radiation environment in space and atmosphere and the main effects that the different types of ionizing particles that are present in these environments may produce on electronic devices. Furthermore, mainly focusing on Single-Event Effects (SEEs), it presents approaches and tools for modeling SEEs and their impact on memories and microprocessors. Additionally, experimental results targeting a Commercial-Off-The-Shelf self-refresh Dynamic RAM are presented. These experiments are based on radiation test campaigns in particle accelerators with neutrons and protons. Finally, an overview of issues and mitigation techniques for microprocessors is exposed

A Survey on Deep Learning Resilience Assessment Methodologies

International audienceDeep Learning (DL) applications are gaining increasing interest in the industry and academia for their outstanding computational capabilities. Indeed, they have found successful applications in various areas and domains such as avionics, robotics, automotive, medical wearable devices, gaming; some have been labeled as safety-critical, as system failures can compromise human life. Consequently, DL reliability is becoming a growing concern, and efficient reliability assessment approaches are required to meet safety constraints. This paper presents a survey of the main DL reliability assessment methodologies, focusing mainly on Fault Injection (FI) techniques used to evaluate the DL resilience. The article describes some of the most representative state-of-the-art academic and industrial works describing FI methodologies at different levels of abstraction. Finally, a discussion of the advantages and disadvantages of each methodology is proposed to provide valuable guidelines for carrying out safety analyses

Effects of heavy ion and proton irradiation on a SLC NAND flash memory

Space applications frequently use flash memories for mass storage data. However, the technology applied in the memory array and peripheral circuity are not inherently radiation tolerant. This work introduces the results of radiation test campaigns with heavy ions and protons on a SLC NAND Flash. Static tests showed different failures types. Single events upsets and raw error cross sections were presented, as well as an evaluation of the occurrences of the events. Characterization of effects on the embedded data registers was also performed.Peer reviewe

Pros and Cons of Fault Injection Approaches for the Reliability Assessment of Deep Neural Networks

In the last years, the adoption of Artificial Neural Networks (ANNs) in safety-critical applications has required an in-depth study of their reliability. For this reason, the research community has shown a growing interest in understanding the robustness of artificial computing models to hardware faults. Indeed, several recent studies have demonstrated that hardware faults induced by an external perturbation or due to silicon wear out and aging effects can significantly impact the ANN inference leading to wrong predictions. This work classifies and analyses the principal reliability assessment methodologies based on Fault Injection at different abstraction levels and with different procedures. Some of the most representative academic and industrial works proposed in the literature are described and the principal advantages, and drawbacks are highlighted

A Survey on Deep Learning Resilience Assessment Methodologies

International audienceDeep Learning (DL) applications are gaining increasing interest in the industry and academia for their outstanding computational capabilities. Indeed, they have found successful applications in various areas and domains such as avionics, robotics, automotive, medical wearable devices, gaming; some have been labeled as safety-critical, as system failures can compromise human life. Consequently, DL reliability is becoming a growing concern, and efficient reliability assessment approaches are required to meet safety constraints. This paper presents a survey of the main DL reliability assessment methodologies, focusing mainly on Fault Injection (FI) techniques used to evaluate the DL resilience. The article describes some of the most representative state-of-the-art academic and industrial works describing FI methodologies at different levels of abstraction. Finally, a discussion of the advantages and disadvantages of each methodology is proposed to provide valuable guidelines for carrying out safety analyses

A Survey on Deep Learning Resilience Assessment Methodologies

Deep Learning (DL) applications are gaining increasing interest in the industry and academia for their outstanding computational capabilities. Indeed, they have found successful applications in various areas and domains such as avionics, robotics, automotive, medical wearable devices, gaming; some have been labeled as safety-critical, as system failures can compromise human life. Consequently, DL reliability is becoming a growing concern, and efficient reliability assessment approaches are required to meet safety constraints. This paper presents a survey of the main DL reliability assessment methodologies, focusing mainly on Fault Injection (FI) techniques used to evaluate the DL resilience. The article describes some of the most representative state-of-the-art academic and industrial works describing FI methodologies at different levels of abstraction. Finally, a discussion of the advantages and disadvantages of each methodology is proposed to provide valuable guidelines for carrying out safety analyses