The terminator : an AI-based framework to handle dependability threats in large-scale distributed systems

With the advent of resource-hungry applications such as scientific simulations and artificial intelligence (AI), the need for high-performance computing (HPC) infrastructure is becoming more pressing. HPC systems are typically characterised by the scale of the resources they possess, containing a large number of sophisticated HW components that are tightly integrated. This scale and design complexity inherently contribute to sources of uncertainties, i.e., there are dependability threats that perturb the system during application execution. During system execution, these HPC systems generate a massive amount of log messages that capture the health status of the various components. Several previous works have leveraged those systems’ logs for dependability purposes, such as failure prediction, with varying results. In this work, three novel AI-based techniques are proposed to address two major dependability problems, those of (i) error detection and (ii) failure prediction. The proposed error detection technique leverages the sentiments embedded in log messages in a novel way, making the approach HPC system-independent, i.e., the technique can be used to detect errors in any HPC system. On the other hand, two novel self-supervised transformer neural networks are developed for failure prediction, thereby obviating the need for labels, which are notoriously difficult to obtain in HPC systems. The first transformer technique, called Clairvoyant, accurately predicts the location of the failure, while the second technique, called Time Machine, extends Clairvoyant by also accurately predicting the lead time to failure (LTTF). Time Machine addresses the typical regression problem of LTTF as a novel multi-class classification problem, using a novel oversampling method for online time-based task training. Results from six real-world HPC clusters’ datasets show that our approaches significantly outperform the state-of-the-art methods on various metrics

Mobile application linking entrepreneurs to mentors and investors

Thesis submitted in partial fulfillment of the requirements for the Degree of Master of Science in Mobile Telecommunication and Innovation at (MSc.MTI) at Strathmore UniversityThere is a growing culture of entrepreneurship in Africa with countries like Kenya becoming centers for innovation and entrepreneurship. This is evidenced by the development of world-leading technological innovations like MPESA - a renowned mobile phone based money transfer platform pioneered by Kenya’s largest telecommunication company, Safaricom. Despite existing potential, young African start-ups and existing businesses in the technology sector are faced with multiple challenges. Lack of access to capital, mentorship and training stand out among key challenges. This study reviews existing systems employed to address concerns such as limited access to funding, mentorship, and training by entrepreneurs. It identifies these systems’ limitations and proposes how they can be improved. The waterfall methodology was used to undertake the reseach and the development of an Android based mobile application that will address the current gap of accessing metors and investors. Out of the total sampled population , 90% of the entrepreneurs confirmed that they had faced difficulties in accessing mentors and investors . The application was validated after development and 95% of the sampled population highly welcomed the adoption of a mobile application that had been developed to address the gap. The developed mobile application will facilitate entrepreneur’s access to mentorship allowing them to gain the skills needed to run their businesses and investors who can inject capital to actualise their ideas and stimulate growth. This is likely to promote entrepreneurship in Kenya and lead to a more stable economy. There is a possibility that most of the African countries will adopt the use of the Android based mobile application

Conception et vérification d'exigences de sûreté temporisées à base de contrats dans les modèles SysML

De nos jours, les systèmes informatiques croissent en taille et en complexité. Intégrés dans des dispositifs de différents domaines tels que l'avionique, l'aéronautique, l'électronique grand public, etc., ils sont souvent considérés comme critiques à l'égard de la vie humaine, des coûts et de l'environnement. Concevoir des systèmes embarqués temps-réel critiques sûrs et fiables est une tâche difficile, étant donné que leurs modèles sont souvent source d'erreurs. Une façon pour les concepteurs de contourner cette difficulté consiste à s'appuyer sur la modélisation compositionnelle de composants logiciels pilotée par les exigences. Le raisonnement à base de contrats permet de construire des composants sûrs à partir des exigences globales du système en interposant des spécifications abstraites et partielles entre les besoins du système et les composants eux-mêmes. Informellement, un contrat modélise le comportement abstrait d'un composant du point de vue de l'exigence à satisfaire (c.a.d garantie) dans un contexte donné (c.a.d. hypothèse). Les contrats peuvent être exploités pour décomposer et tracer les exigences au cours d'un développement itératif, mais aussi pour effectuer une vérification compositionnelle de la satisfaction des exigences. Dans cette thèse, nous présentons une méthodologie de raisonnement à base de contrats pour la conception et la vérification de systèmes sûrs développés en SysML. Ainsi, nous définissons en UML/SysML la syntaxe des contrats et des relations de raffinement entre contrats et/ou composants qui sont utilisées pour prouver la correction du système par rapport aux exigences. Ensuite, nous proposons un cadre formel qui modélise la sémantique d'un modèle UML/SysML étendu par des contrats selon une variante d'automates temporisés entrée/sortie et nous définissons la correspondance entre ces concepts. Nous formalisons les relations de raffinement par la relation d'inclusion de traces et nous prouvons leurs propriétés compositionnelles ce qui assure la correction de la méthodologie. L'approche est instanciée pour le profil OMEGA et la boîte à outils IFx2 qui génère partiellement les obligations de preuve. Finalement, plusieurs études de cas dont une issue de l'industrie complètent la théorie pour évaluer l'approche à base de contrats et ses résultats et les comparer aux méthodes classiques de model-checking.Nowadays computer systems grow larger in size and more complex. Embedded in devices from different domains like avionics, aeronautics, consumer electronics, etc., they are often considered critical with respect to human life, costs and environment. A development that results in safe and reliable critical real-time embedded systems is a challenging task, considering that errors are accidentally inserted in the design. A way for system designers to tackle this issue is to use a compositional design technique based on components and driven by requirements: it allows to infer from global requirements, component properties that must locally hold. Contract-based reasoning allows to compositionally derive correct components from global system requirements by interposing abstract and partial specifications for components. Informally, a contract models the abstract behavior a component exhibits from the point of view of the requirement to be satisfied (i.e. guarantee) in a given context (i.e. assumption). Contracts can be used to decompose and trace requirements during iterative design, but also to perform compositional verification of requirement satisfaction. In this thesis, we present a methodology for reasoning with contracts during system design and verification within SysML. Thus, we define the syntax for contracts in UML/SysML, as well as a set of refinement relations between contracts and/or components in order to prove the system's correctness with respect to requirements. Next, we provide a formal framework that models the semantics of a UML/SysML model extended with contracts as a mapping of the language concepts to a variant of Timed Input/Output Automata. The refinement relations are formalized based on the trace inclusion relation and compositional properties are proved to hold which ensures the soundness of the methodology. The approach is instantiated for the OMEGA Profile and IFx2 toolset with partial automatic generation of proof obligations. Finally, the approach is applied on several case studies, including an industry-grade system model, which show its efficiency by comparative verification results