Komplexe Muster neuronaler Aktivität entstehen während der Sharp-wave Ripples (SWRs) im Hippocampus und während der Up States im Neokortex (Zuständen mit hoher Aktivität). Sequenzen von Verhalten, die in der Vergangenheit erlebt wurden, werden während des komplexen Musters abgespielt. Die zugrunde liegenden Mechanismen sind nicht gründlich erforscht: Wie können kleine synaptische Veränderungen die großflächige Netzwerkaktivität während des Gedächtnisabrufes und der Gedächtniskonsolidierung kontrollieren? Im ersten Teil dieser Abhandlung wird die Hypothese aufgestellt, dass eine schwache synaptische Konnektivität zwischen Hebbschen Assemblies von der bereits vorhandenen rekurrenten Konnektivität gefördert wird. Diese Hypothese wird auf folgende Weise geprüft: die vorwärts gekoppelten Assembly-Sequenzen werden in neuronale Netzwerke eingebettet, mit einem Gleichgewicht zwischen exzitatorischer und inhibitorischer Aktivität. Simulationen und analytische Berechnungen haben gezeigt, dass rekurrente Verbindungen innerhalb der Assemblies zu einer schnelleren Signalverstärkung führen, was eine Reduktion der notwendigen Verbindungen zwischen den Assemblies zur Folge hat. Diese Aktivität kann entweder von kleinen sensorisch ähnlichen Inputs hervorgerufen werden oder entsteht spontan infolge von Aktivitätsschwankungen. Globale -- möglicherweise neuromodulatorische -- Änderungen der neuronalen Erregbarkeit können daher die Netzwerkzustände steuern, die Gedächnisabruf und die Konsolidierung begünstigen. Der zweite Teil der Arbeit geht der Herkunft der SWRs nach, die in vitro beobachtet wurden. Neueste Studien haben gezeigt, dass SWR-ähnliche Erscheinungen durch optogenetische Stimulation der Subpopulationen von inhibitorischen Neuronen hervorgerufen werden können (Schlingloff et al., 2014). Um diese Ergebnisse zu erklären wird ein de-inhibierendes Schaltkreis-Modell diskutiert, das die beobachteten Populationsausbrüche generieren kann. Die Auswirkungen der pharmakologischen GABAergischen Modulatoren auf die SWR-Häufigkeit werden in vitro untersucht. Die gewonnenen Ergebnisse wurden in Rahmen des Schaltkreis-Modells analysiert. Insbesondere wird den folgenden Fragen nachgegangen: Wie unterdrückt Gabazine, ein GABA_A-Rezeptor-Antagonist, die Entwicklung von SWRs? Wird das Zeitintervall zwischen SWRs durch die Dynamik der GABA_B Rezeptoren moduliert? / Complex patterns of neural activity appear during up-states in the neocortex and sharp-wave ripples (SWRs) in the hippocampus, including sequences that resemble those during prior behavioral experience. The mechanisms underlying this replay are not well understood. How can small synaptic footprints engraved by experience control large-scale network activity during memory retrieval and consolidation? In the first part of this thesis, I hypothesise that sparse and weak synaptic connectivity between Hebbian assemblies are boosted by pre-existing recurrent connectivity within them. To investigate this idea, sequences of assemblies connected in a feedforward manner are embedded in random neural networks with a balance of excitation and inhibition. Simulations and analytical calculations show that recurrent connections within assemblies allow for a fast amplification of signals that indeed reduces the required number of inter-assembly connections. Replay can be evoked by small sensory-like cues or emerge spontaneously by activity fluctuations. Global--potentially neuromodulatory--alterations of neuronal excitability can switch between network states that favor retrieval and consolidation. The second part of this thesis investigates the origin of the SWRs observed in in-vitro models. Recent studies have demonstrated that SWR-like events can be evoked after optogenetic stimulation of subpopulations of inhibitory neurons (Schlingloff et al., 2014; Kohus et al., 2016). To explain these results, a 3-population model is discussed as a hypothetical disinhibitory circuit that could generate the observed population bursts. The effects of pharmacological GABAergic modulators on the SWR incidence in vitro are analysed. The results are discussed in the light of the proposed disinhibitory circuit. In particular, how does gabazine, a GABA_A receptor antagonist, suppress the generation of SWRs? Another explored question is whether the slow dynamics of GABA_B receptors is modulating the time scale of the inter-event intervals.

Les plates-formes MPSoC permettent de satisfaire les contraintes de performance, de flexibilité et de consommation énergétique requises par les systèmes embarqués émergents. Elles intègrent un nombre important de processeurs, des blocs de mémoire et des périphériques, hiérarchiquement organisés par un réseau d'interconnexion. Le développement du logiciel est réputé difficile, notamment dû à la gestion d'un grand nombre d'entités (tâches/threads/processus). L'exécution concurrente de ces entités permet d'exploiter efficacement l'architecture mais complexifie le processus de mise au point et notamment l'analyse des erreurs. D'une part, les exécutions peuvent être non-déterministes notamment dû à la concurrence, c'est à dire qu'elles peuvent se dérouler d'une manière différente à chaque reprise. En conséquence, il n'est pas garanti qu'une erreur se produirait durant la phase de mise au point. D'autre part, la complexité de l'architecture et de l'exécution peut rendre trop important le nombre d'éléments à analyser afin d'identifier une erreur. Il pourrait donc être difficile de se focaliser sur des éléments potentiellement fautifs. Un des défis majeurs du développement logiciel MPSoC est donc de réduire le temps de la mise au point. Dans cette thèse, nous proposons une méthodologie de mise au point qui aide le développeur à identifier les erreurs dans le logiciel MPSoC. Notre premier objectif est de déboguer une même exécution plusieurs fois afin d'analyser des sources potentielles de l'erreur jusqu'à son identification. Nous avons donc identifié les sources de non-déterminisme MPSoC et proposé des mécanismes de ré-exécution déterministe les plus adaptés. Notre deuxième objectif vise à minimiser les ressources pour reproduire une exécution afin de satisfaire la contrainte MPSoC de maîtrise de l'intrusion. Nous avons donc utilisé des mécanismes efficaces de ré-exécution déterministe et considéré qu'une partie du comportement non-déterministe. Le troisième objectif est de permettre le passage à l'échelle, c'est à dire de déboguer des exécutions caractérisées par un nombre d'éléments de plus en plus croissant. Nous avons donc proposé une méthode qui permet de circonscrire et de déboguer qu'une partie de l'exécution. De plus, cette méthode s'applique aux différents types d'architectures et d'applications MPSoC. / MPSoC platforms provide high performance, low power consumption and flexi-bility required by the emerging embedded systems. They incorporate many proces-sing units, memory blocs and peripherals, hierarchically organized by interconnec-tion network. The software development is known to be difficult, namely due to themanagement of multiple entities (tasks/threads/processes). The concurrent execu-tion of these entities allows to exploit efficiently the architecture but complicatesthe refinement process of the software and especially the debugging activity. Onthe one hand, the executions of the software can be non-deterministic, namely dueto the concurrency, i.e. they perform differently each time. Consequently, thereis no guaranties that an error will occur during the debugging activity. On theother hand, the complexity of the architecture and the execution can increase theelements to be analyzed in the debugging process. As a result, it can be difficultto concentrate on the potentially faulty elements. Therefore, one of the most im-portant challenges in the development process of MPSoC software is to reduce thetime of the refinement process.In this thesis, we propose a new methodology to refine the MPSoC softwarewhich helps the developers to do the debugging activity. Our first objective is tobe able to debug the same execution several times in order to analyze potentialsources of the error. To do so, we identified the sources of non-determinism in theMPSoC software executions and propose the most appropriate methods to recordand replay them. Our second objective is to reduce the execution overhead requi-red by the record mechanisms to limit the intrusiveness which is an importantMPSoC constraint. To accomplish this objective, we consider a part of the non-deterministic behaviour and selected efficient record-replay methods. The thirdobjective is to provide a scalable solution, i.e. to be able to debug more and morecomplex executions, characterized by an increasing number of elements. Therefore,we propose a partial replay method which allows to isolate and debug a fraction ofthe execution elements. Moreover, this method applies to different types of archi-tectures and applications MPSoC.

Submitted by Haroudo Xavier Filho (haroudo.xavierfo@ufpe.br) on 2016-03-11T14:34:26Z No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) DissertacaoIvanFranca.pdf: 1367108 bytes, checksum: 8ceed302b395b606d9ac49b5a05987db (MD5) / Made available in DSpace on 2016-03-11T14:34:26Z (GMT). No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) DissertacaoIvanFranca.pdf: 1367108 bytes, checksum: 8ceed302b395b606d9ac49b5a05987db (MD5) Previous issue date: 2015-08-14 / Os quadros de controle IEEE 802.11 desempenham funções importantes na rede sem fio. Dentre elas estão o controle de acesso ao meio de comunicação, a recuperação de quadros armazenados no Ponto de Acesso e a confirmação do recebimento de blocos de quadros ou de certos tipos de quadros. Apesar da importância dos quadros de controle, eles são vulneráveis a ataques de forjação, manipulação e reinjeção devido a inexistência de mecanismos de proteção. Este trabalho propõe um esquema de segurança para quadros de controle em redes IEEE 802.11 a fim de evitar esses ataques. A proposta se diferencia dos trabalhos relacionados por prover um alto grau de segurança em todos os seus módulos com baixo impacto na vazão da rede. Além disso, a proposta não incorre nas fraquezas que eles possuem na contenção dos ataques de reinjeção e no processo de geração e distribuição de chaves. / IEEE 802.11 control frames play important role in the wireless network. Among them are the medium access control, the retrieving of buffered frames in the Access Point, and the acknowledgment of block of frames or certain types of frames. Despite their importance, control frames remain vulnerable to forging, tampering, and replay attacks due to lack of protection mechanisms. This work proposes a security scheme for IEEE 802.11 control frames to prevent such attacks. Our proposal differs from related work by providing a high level of security in all modules along with low impact on network throughput. Furthermore, the proposal avoid the weaknesses that they have in the restraint the replay attacks and in the key generation and distribution process.

Thesis deals with testing of selected vulnerabilities from the IEC 61850 standard and following design of mitigation measures for selected vulnerabilities. Author simulated vulnerabilities of the GOOSE protocol, NTP attack and attack ona MMS client. Those attacks were GOOSE stNum, GOOSE semantic, GOOSE test bit,GOOSE replay, GOOSE flood, NTP spoofing and MMS password capture. Attacks on protocols GOOSE and MMS were successful, attack on NTP was only partially successful since the device confirmed receiving spoofed time, however it did not change it’s inner clock. Author then designed possible mitigation measures. Tool for automatic testing of selected vulnerabilities, parser for the GOOSE protocol and lightweight multiplatform parser for configuration files were created as well.The outcome of this thesis allows the implementation of lager scale tool for penetration testing of industrial networks as well as it allows implementation of discussed mitigation measures.

This thesis deals with the application of bounded model checking method for self-healing assurance of concurrency related problems. The self-healing is currently interested in the Java programming language. Therefore, it concetrate mainly on the model checker Java PathFinder which is built for handling Java programs. The verification method is implemented like the Record&Replay trace strategy for navigation through a state space and performance bounded model checking from reached state through the use of Record&Replay trace strategy. Java PathFinder was extended by new moduls and interfaces in order to perform the bounded model checking for self-healing assurance. Bounded model checking is applied at the neighbourhood of self-healing.

The testing of software for robot controllers has become increasingly difficult as robotic systems become more complex. As the complexity of the systems increases, the number of hardware systems that the robot relies on also grows. This poses a challenge in testing robot controllers, which is crucial to ensure that robots function safely and effectively in their intended applications. While simulation can be used as a platform for software testing, it is not feasible to simulate everything in a virtual environment, especially when test cases require physical connections to hardware for input and output signals sent to robot controllers. Therefore, the objective of this thesis is to replicate I/O device network communication in order to enhance virtual testing processes. The approach employed involves capturing real-time network traffic, modifying and rebuilding it, and subsequently replaying it. The work examines existing academic research on these approaches and technologies, and investigates the specific challenges in the testing process by conducting research within a company leading globally in industrial robot development. A conceptual model is proposed, and a prototype is developed. The solution demonstrates potential in addressing the current challenges in robot controller testing by enabling network capture, modification, and level 4 network traffic replay. However, experimental results reveal various limitations, such as significant delays in generating responses. Therefore, further research and development are required if the solution is to be implemented in a real-world setting.

Researchers and application designers need repeatable methods to evaluateapplications/systems over WiFi. It is hard to reproduce evaluations overWiFi because of rapidly changing wireless quality over time. In this degreeproject, we present NemFi, a trace-driven emulator for accurately recordingthe WiFi trac and later using it to emulate WiFi links in a repeatable fashion.First, we present the advantages of trace-driven emulation over simulationand experimentation. We capture the uctuating WiFi link conditionsin terms of capacity and losses over time and replay captured behavior forany application running in the emulator. Current record-and-replay techniquesfor web trac and cellular networks do not work for WiFi becauseof their inability to distinguish between WiFi losses and losses due to selfinducedcongestion. They are also lacking other WiFi specic features. Inthe absence of a trace-driven emulator for WiFi, NemFi is also equipped toavoid self-induced packet losses. It is thus capable of isolating WiFi relatedlosses which are then replayed by the NemFi's replay. NemFi's record alsoaddresses the frame aggregation and the eect it has on the actual datatransmission capability over the wireless link. NemFi can record frame aggregation,at all instants of the record phase and later accurately replays theaggregation.Experimental results demonstrate that NemFi is not only accurate inrecording the variable-rate WiFi link but also in capturing cross-trac. NemFialso replays the recorded conditions with considerable accuracy. / Forskare och applikationsdesigners behöver repeterbara metoder för att utvärderaapplikationer och system via WiFi. Det är svårt att reproducera utvärderingar genom WiFi eftersom den trådlösa kvalit´en snabbt förändras över tid. I denna rapport presenterar vi NemFi, en spårstyrd emulator för att noggrant registrera WiFi-trafiken och senare använda den för att emulera WiFi-länkar påett repeterbart sätt. Först presenterar vi fördelarna med spårstyrd emulering jämfört med simulering och experiment. Vi fångar de varierande WiFi förhållanden med avseende påkapacitet och förluster över tid och spelar upp fångat beteende för alla applikationer som körs i emulatorn. Nuvarande inspelning och uppspelningstekniker för webbtrafik och mobilnät fungerar inte för WiFi pågrund av deras oförmåga att skilja mellan WiFi-förluster ochförluster pågrund av självinducerad överbelastning. De saknar ocksåandraWiFi-specifika funktioner. I avsaknad av en spårdriven emulator för WiFi är NemFi ocksåutrustade för att undvika självinducerade paketförluster. Den kan alltsåisolera WiFi-relaterade förluster som sedan spelas upp igen av NemFi: s uppspelning. NemFi adresserar ocksåramaggregering och det är effekten påfaktiska dataöverföringsförmåga via den trådlösa länken. NemFi kan spela in ramsamling, vid alla ögonblick i inspelningsfasen och ersätter senare noggrant aggregeringen.Experimentella resultat visar att NemFi inte bara är användbart när det gäller att registrera WiFi-länken med variabel hastighet, utan ocksåför att fånga tvärgående trafik. NemFi ersätter ocksåde inspelade förhållandena medbetydande noggrannhet.

Tesis por compendio / [ES] Erlang es un lenguaje de programación funcional con concurrencia mediante paso de mensajes basado en el modelo de actores. Éstas y otras características lo hacen especialmente adecuado para aplicaciones distribuidas en tiempo real acrítico. En los últimos años, la popularidad de Erlang ha aumentado debido a la demanda de servicios concurrentes. No obstante, desarrollar sistemas Erlang libres de errores es un reto considerable. A pesar de que Erlang evita muchos problemas por diseño (por ejemplo, puntos muertos), algunos otros problemas pueden aparecer. En este contexto, las técnicas de testing y depuración basadas en métodos formales pueden ser útiles para detectar, localizar y arreglar errores de programación en Erlang. En esta tesis proponemos varios métodos para testing y depuración en Erlang. En particular, estos métodos están basados en modelos semánticos para concolic testing, pruebas basadas en propiedades, depuración reversible con consistencia causal y repetición reversible con consistencia causal de programas Erlang. Además, probamos formalmente las principales propiedades de nuestras propuestas y diseñamos herramientas de código abierto que implementan estos métodos. / [CA] Erlang és un llenguatge de programació funcional amb concurrència mitjançant pas de missatges basat en el model d'actors. Estes i altres característiques el fan especialment adequat per a aplicacions distribuïdes en temps real acrític. En els últims anys, la popularitat d'Erlang ha augmentat degut a la demanda de servicis concurrents. No obstant, desenvolupar sistemes Erlang lliures d'errors és un repte considerable. Encara que Erlang evita molts problemes per disseny (per exemple, punts morts), alguns altres problemes poden aparéixer. En este context, les tècniques de testing y depuració basades en mètodes formals poden ser útils per a detectar, localitzar y arreglar errors de programació en Erlang. En esta tesis proposem diversos mètodes per a testing i depuració en Erlang. En particular, estos mètodes estan basats en models semàntics per a concolic testing, testing basat en propietats, depuració reversible amb consistència causal i repetició reversible amb consistència causal de programes Erlang. A més, provem formalment les principals propietats de les nostres propostes i dissenyem ferramentes de codi obert que implementen estos mètodes. / [EN] Erlang is a message-passing concurrent, functional programming language based on the actor model. These and other features make it especially appropriate for distributed, soft real-time applications. In the recent years, Erlang's popularity has increased due to the demand for concurrent services. However, developing error-free systems in Erlang is quite a challenge. Although Erlang avoids many problems by design (e.g., deadlocks), some other problems may appear. Here, testing and debugging techniques based on formal methods may be helpful to detect, locate and fix programming errors in Erlang. In this thesis we propose several methods for testing and debugging in Erlang. In particular, these methods are based on semantics models for concolic testing, property-based testing, causal-consistent reversible debugging and causal-consistent replay debugging of Erlang programs. We formally prove the main properties of our proposals and design open-source tools that implement these methods. / Palacios Corella, A. (2020). Formal Methods for Constraint-Based Testing and Reversible Debugging in Erlang [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/139076 / Compendio

The neural circuitry responsible for memory consists of complex components with dynamic interactions. In hippocampal area CA1, interactions between excitatory pyramidal cells and inhibitory interneurons shape ensemble activity which encodes sequential experience. An extremely diverse set of inhibitory interneurons, with variation in gene expression, synaptic targeting, state-dependent activity, and connectivity, contribute substantially to circuit activity, such as theta and sharp wave-ripple oscillations. The precise roles of each interneuron group is not well understood, though characterization of their activity reveals mechanisms underlying hippocampal circuit computation. In this dissertation, I aim to identify and disrupt interactions between pyramidal cells and local interneurons to clarify their role in shaping cell assembly activity. We characterized axo-axonic cell activity in sharp wave-ripples, and compared their control of pyramidal cell activity and ripple events to parvalbumin expressing neurons. We identified pyramidal cell-interneuron interactions during ripples, suggesting they serve as lateral inhibitors between cell assemblies. We additionally developed and implemented a novel neural device to explore the role of cannabinoid disruption of hippocampal oscillations and organization of assemblies in vivo in awake animals. We demonstrate that cannabinoid receptor type 1 within CA1 is responsible for suppression of theta and SPW-Rs. We also found that cannabinoid activation within CA1 circuitry, regardless of muted input from CA3, was sufficient to disrupt sharp wave-ripples, likely through interference of pyramidal cell-interneuron interactions. The work in this dissertation provides insight suggesting that interneuron activity must be studied at the spiking timescale to characterize their control over cell assembly activity. / Doctor of Philosophy / Understanding how the brain creates memory remains one of the greatest questions in the field of neuroscience. Coordinated brain activity serves to build communication on large and small scales, across brain regions and within circuits consisting of small groups of neurons. Precise coordination of activity and communication across neurons and regions is thought to build salient experience, which is achieved through the timing of neuron action potentials, or spikes. Neurons receive thousands of inputs that control their spiking activity. "Go and stop" signals from excitatory and inhibitory interneurons act to conduct synchronized activity, which is required for proper circuit function. Importantly, coordinated spiking across large groups of neurons is responsible for observed "brain waves", or oscillations, which reflect organized activity. In CA1 of the hippocampus, there are >20 subtypes of interneurons that all make distinct contributions to memory function, and the roles of these interneurons have not been fully studied within behaving animals. As engineers develop new tools, new methods become available to study and classify how unique groups of interneurons play a part in circuit activity. Thus, we sought to characterize the role of axo-axonic cells, a specialized interneuron with strong control over spiking activity, in hippocampal oscillations that are responsible for memory encoding and consolidation. We identified a new role for axo-axonic cells in the regulation of pyramidal cell spiking in sharp wave-ripple oscillations. Additionally, we developed a novel neural device that allowed us to investigate the mechanisms that underlie cannabinoids, molecules found in Cannabis sativa, and memory dysfunction. We leveraged the multifunctionality of our T-DOpE probe to focally deliver synthetic cannabinoid into the hippocampus in combination with optical control of circuits, with simultaneous recording of activity. We found that cannabinoids acting within CA1 sufficiently disrupt hippocampal oscillations, likely through hindering pyramidal cell-interneuron interactions. Together, these findings suggest that the spatial and temporal resolution required to study diverse roles of interneurons is high, and experiments designed to explore interneuron activity should especially emphasize fine time-scales.

The Internet of things (IoT) device has been widely used in various fields, and its market is expanding rapidly. However, the growing usage of IoT devices also brings more security concerns. The smart door lock is one of the smart home IoT devices that need to be designed securely. This thesis work aims to evaluate and investigate the security aspect of the newest smart door lock. This thesis first provides an introduction and background of penetration testing and creates the threat model. Based on the threat model, some testings are conducted, including state consistency, Man-In-The-Middle (MITM) attack, replay attack, reverse engineering, GPS spoofing, Denial of service (DoS) attack. The result indicates that penetration tests reveal some security problems on the tested device, especially in the access log, traffic between application and server, and the ability of resistance disruption on the WiFi access point. / IoT-enheten har använts i stor utsträckning inom olika områden och dess marknad expanderar snabbt. Den ökande användningen av IoT-enheter medför dock också fler säkerhetsproblem. Det smarta dörrlåset är en av de smarta hem IoT-enheterna som måste utformas säkert. Detta examensarbete syftar till att utvärdera och undersöka säkerhetsaspekten av det nyaste smarta dörrlåset. Denna avhandling ger först en introduktion och bakgrund av penetrationstestning och skapar hotmodellen. Baserat på hotmodellen genomförs vissa tester, inklusive tillståndskonsistens, MITM attack, replay attack, reverse engineering, GPS spoofing, DoS attack. Resultatet indikerar att penetrationstester avslöjar vissa sårbarheter på den testade enheten, särskilt i åtkomstloggen, trafik mellan applikation och server och förmågan till motståndsavbrott på WiFi-åtkomstpunkten.