O paradigma SDN simplifica o gerenciamento da rede ao concentrar todas as tarefas de controle em uma única entidade, o controlador. Nesse modo de operação, os dispositivos de encaminhamento só funcionam de forma completa enquanto conectados a um controlador. Neste contexto, a literatura recente identificou questões fundamentais, como o isolamento de dispositivos em função de disrupções na rede e a sobrecarga de um controlador, e propôs estratégias de posicionamento do controlador para enfrentá-las. Contudo, as propostas atuais têm limitações cruciais: (i) a conectividade dispositivo-controlador é modelada usando um único caminho, ainda que na prática possam ocorrer múltiplas conexões concorrentes; (ii) alterações no comportamento da chegada de novos fluxos são manipulados sob demanda, assumindo que a rede em si pode sustentar altas taxas de requisição; e (iii) mecanismos de recuperação de falhas requerem informações pré-definidas, que, por sua vez, não são otimizadas. Esta dissertação apresenta Survivor, uma nova abordagem de posicionamento do controlador para redes WAN que visa enfrentar esses desafios. A abordagem trata três aspectos de forma explícita durante o projeto da rede: a conectividade, a capacidade e a recuperação. Além disso, tais aspectos são planejados para dois estados distintos da rede: pré e pós-disrupção. Em outras palavras, a rede é configurada da melhor forma tanto para operação normal, quanto para operação após eventos de disrupção. Para este fim, a abordagem é dividida em duas etapas. A primeira define o posicionamento de instâncias do controlador, enquanto a segunda especifica uma lista de controladores de backup para cada dispositivo na rede. Ademais, são desenvolvidas duas estratégias com base na abordagem Survivor. A primeira, implementada em Programação Linear Inteira, garante uma solução ótima a um custo computacional alto. A segunda, implementada através de heurísticas, fornece soluções sub-ótimas a um custo computacional muito mais baixo. Comparações com o estado-da-arte mostram que a abordagem Survivor provê ganhos significativos na sobrevivência (identificado na probabilidade mais baixa de perda de conectividade) e no estado convergente da rede através de mecanismos de recuperação mais inteligentes. / The SDN paradigm simplifies network management by focusing all control tasks into a single entity, the controller. In this way, forwarding devices can only operate correctly while connected to a logically centralized controller. Within this context, recent literature identified fundamental issues, such as device isolation due to disruptions in the network and controller overload, and proposed controller placement strategies to tackle them. However, current proposals have crucial limitations: (i) device-controller connectivity is modeled using single paths, yet in practice multiple concurrent connections may occur; (ii) peaks in the arrival of new flows are only handled on-demand, assuming that the network itself can sustain high request rates; and (iii) failover mechanisms require predefined information which, in turn, has been overlooked. This dissertation presents Survivor, a novel controller placement approach for WAN networks that addresses these challenges. The approach explicitly considers the following three aspects in the network design process: connectivity, capacity and recovery. Moreover, these aspects are planned for two distinct states of the network: pre and postdisruption. In other words, the network is configured optimally for both normal operation and for operation after disruption events. To this end, the approach is divided into two steps. The first defines the positioning of the controller instances, and the second specifies a list of backup controllers for each device on the network. Moreover, two strategies based on Survivor are developed. The first strategy, implemented with Integer Linear Programming, guarantees an optimal solution with a high computational cost. The second strategy, implemented using heuristics, provides sub-optimal solutions with a much lower computational cost. Comparisons to the state-of-the-art show that the Survivor approach provides significant increases in network survivability (identified with the lowest probability of connectivity loss) and converged network state through smarter recovery mechanisms.

Sjukvårdstaktiken idag grundar sig idag i reglementen och handböcker där sjukvårdsgrupper bär det Röda Korset för att kunna få de skydd som den internationella humanitära rätten ger. Dessa lagar gäller i väpnade konflikter och ska respekteras av alla parter i en konflikt. Trots dessa lagar sker attacker riktade mot sjukvårdsenheter medvetet. Senast i Rysslands invasion av Ukraina har det enligt WHO skett 859 attacker mot sjukvårdsenheter.  När sjukvårdsgrupper ses som legitima mål för en motståndare skapas ett problem och ett dilemma om svenska sjukvårdsgrupper bör bära det Röda Korset för att få de skydd som den internationella humanitära rätten ger, eller om gruppen i stället bör skyddas genom att inte utmärka dem med det Röda Korset. Syftet med arbetet är att utforska, om en sjukvårdsgrupp bör bära det Röda Korset eller inte, genom att besvara frågeställningen: Vad händer med en sjukvårdsgrupps skydd när de inte bär det Röda Korset, utifrån skyddslökens lager? Slutsatsen är att skyddet kommer att öka på sjukvårdsgruppen om de inte bär det Röda Korset, men att det då måste beslutas på högre nivåer och alla i Försvarsmakten måste göra likadant. De reglementen som finns för dagens sjukvårdtaktik behöver ses över och revideras då den tänkta motståndaren inte följer krigets lagar som de är tänkta att göra. Sjukvårdsgruppers uppträdande behöver också ändras för att deras egna skydd ska kunna öka ytterligare. / Medical tactics today are based on the regulations and manuals where medical units wear the Red Cross to get the protection that international humanitarian law gives. These laws apply in armed conflicts and must be respected by all parts in a conflict. Despite these laws, attacks targeting healthcare facilities still occur. Most recently in Russia's invasion of Ukraine, according to the WHO, there have been 859 attacks on medical units. When medical units are seen as legitimate targets for an adversary, it creates a problem and a dilemma as to how Swedish medical units should wear the red cross to receive the protections that international humanitarian law provides, or whether one should instead protect medical units by not using the Red Cross.  The aim of this essay is to explore, if a medical unit should wear the Red Cross or not by answering the question: What happens to a medical unit’s protection when they don't wear the Red Cross, based on the layer of system survivability? The conclusion is that protection will increase for the health care group if not wearing the Red Cross, but it must be joint decisions within the Armed Forces, and everyone must do the same.  The regulations that exist for today's medical unit tactics need to be reviewed and revised as the adversaries that exist today do not follow the laws of war as they are supposed to. Medical units’ tactics need to be changed so that their own protection can increase.

Autonomous mobile robots in agriculture have brought digital transformations with new automation technologies. Mundane tasks in agricultural fields involve long-term deployment of scheduled assignments done over long working hours. Hectares of land also require much distance to be traveled by the robot, wherein surviving without stranding powerless amid operation is a key factor towards long-term autonomy. Scheduling tasks are usually required as the mobile robot’s battery life is limited. However, dynamic and unstructured outdoor environments make it practically challenging to abide by a schedule even with fixed charging routines. Most robot systems use hard thresholds and fixed periods to decide when to charge. These measures produce behaviors that ignore the safety risk by not considering current conditions. Instead, the robot should adaptively return to the charger or call for human assistance. Safety was a score in this work that represented the robot’s ability to return to the charger at any time. This thesis proposes a real-time safety watchdog that exploits parameters like charger distance, mileage, and current battery status to calculate safety. Hence, a safety-constraint based approach is followed to flexibly sustain survivability during long-term deployments.This work compared a typical rule-based system to the real-time safety watchdog that monitors multiple parameters based on the battery state. Simulated results empirically showed that the latter approach ensures survivability and maintains a healthy performance that supports long-term autonomy. The concept of a real-time safety watchdog is also showcased on a physical robot, pushing statistical evaluation that uses values of long-term deployment as future work. Although a watchdog ensures survivability to a planned schedule, adapting the experience in the upcoming schedule can be worked upon to continue this work. / Autonoma mobila robotar inom jordbruket har lett till digitala förändringar med ny automationsteknik. Vanliga arbetsuppgifter inom jordbruket innebär långvariga, schemalagda uppdrag som utförs under långa arbetstider. Hektar av mark kräver också att roboten färdas långa sträckor, och att överleva utan att stranda utan ström mitt i arbetet är en nyckelfaktor för långsiktig autonomi. Schemaläggningsuppgifter krävs vanligtvis eftersom den mobila robotens batteritid är begränsad. Dynamiska och ostrukturerade utomhusmiljöer gör det dock praktiskt taget svårt att följa ett schema även med fasta laddningsrutiner. De flesta robotsystem använder hårda tröskelvärden och fasta perioder för att bestämma när laddning ska ske. Dessa åtgärder ger upphov till beteenden som ignorerar säkerhetsrisken genom att de inte tar hänsyn till de aktuella förhållandena. I stället bör roboten adaptivt återvända till laddaren eller kalla på mänsklig hjälp. Säkerheten var ett poäng i detta arbete som representerade robotens förmåga att återvända till laddaren när som helst. I den här avhandlingen föreslås en säkerhetsövervakare i realtid som utnyttjar parametrar som laddningsavstånd, körsträcka och aktuell batteristatus för att beräkna säkerheten. Därför följs en säkerhetsbegränsningsbaserad strategi för att flexibelt upprätthålla överlevnadsförmågan under långvariga utplaceringar.I detta arbete jämfördes ett typiskt regelbaserat system med en säkerhetsövervakningshund i realtid som övervakar flera parametrar baserat på batteriets status. Simulerade resultat visade empiriskt att den senare metoden säkerställer överlevnadsförmåga och upprätthåller en sund prestanda som stöder långsiktig autonomi. Konceptet med en säkerhetsövervakningshund i realtid presenteras också. på en fysisk robot, genom att trycka på statistisk utvärdering som använder värden för långsiktig användning som framtida arbete. Även om en vakthund säkerställer överlevnadsförmåga till en planerad tidtabell, kan det vara svårt att anpassa erfarenheterna till den kommande tidtabellen. kan man arbeta med för att fortsätta detta arbete.

The emergence of cloud computing has transformed the potential of robotics by enabling multi-robotic teams to fulfil complex tasks in the cloud. This paradigm is known as “cloud robotics” and relieves robots from hardware and software limitations, as large amounts of available resources and parallel computing capabilities are available in the cloud. The introduction of cloud-enabled robots alleviates the need for computationally intensive robots to be built, as many, if not all, of the CPU-intensive tasks can be offloaded into the cloud, resulting in multi-robots that require much less power, energy consumption and on-board processing units. While the benefits of cloud robotics are clearly evident and have resulted in an increase in interest among the scientific community, one of the biggest challenges of cloud robotics is the inherent communication challenges brought about by disconnections between the multi-robotic system and the cloud. The communication delays brought about by the cloud disconnection results in robots not being able to receive and transmit data to the physical cloud. The unavailability of these robotic services in certain instances could prove fatal in a heterogeneous environment that requires multi-robotic teams to assist with the saving of human lives. This niche area is relatively unexplored in the literature. This work serves to assist with the challenge of disconnection in cloud robotics by proposing a survivable cloud multi-robotics (SCMR) framework for heterogeneous environments. The SCMR framework leverages the combination of a virtual ad hoc network formed by the robot-to-robot communication and a physical cloud infrastructure formed by the robot-to-cloud communications. The Quality of Service (QoS) on the SCMR framework is tested and validated by determining the optimal energy utilization and Time of Response (ToR) on drivability analysis with and without cloud connection. The experimental results demonstrate that the proposed framework is feasible for current multi-robotic applications and shows the survivability aspect of the framework in instances of cloud disconnection. / School of Computing / M.Sc. (Computer Science)

When an aircraft is aerodynamically or structurally damaged in battle, it may not able to complete the mission and the damage may cause its loss. The subject of aircraft battle survivability is one of critical concern to many disciplines, whether military or civil. This thesis considered and focused on Computational Fluid Dynamics [CFD] predictions and experimental investigations into the effects of simulated battle damage on the low-speed aerodynamics of a fmite aspect ratio wing. Results showed that in two-dimensional [2d] and three-dimensional [3D] CFD simulations, Fluent's® models work reasonably well in predicting jets flow structures, pressure distributions, and pressure-coefficient Cp's contours but not for aerodynamic coefficients. The consequences were therefore that CFD prediction was poor on aerodynamic-coefficients increments. The prediction of Cp's achieved good agreement upstream and near the damage hole, but showed poor agreement at downstream of the hole. For the flow structure visualisation, at both weak and strong jet incidences, the solver always predicted pressure-distribution-coefficient lower at upstream and higher at downstream. The results showed relatively good agreement for the case of transitional and strong jet incidences but slightly poor for weak jet incidences. From the experimental results of Finite Wing, the increments for Aspect-ratio, AR6, AR8 and ARIO showed that as damage moves out towards the tip, aerodynamic-coefficients increments i.e. lift-loss and drag-rise decreased, and pitching-moment-coefficient increment indicated a more positive value at all incidence ranges and at all aspect ratios. Increasing the incidence resulted in greater magnitudes of lift-loss and drag-rise for all damage locations and aspect ratios. At the weak jet incidence 4° for AR8 and in all of the three damage locations, the main characteristics of the weak-jet were illustrated clearly. The increments were relatively small. Whilst at 8°, the flow structure was characterised as transitional to stronger-jet. In Finite Wing tests and for all damage locations, there was always a flow structure asymmetry. This was believed to be due to gravity, surface imperfection, and or genuine feature. An 'early strong jet' that indicated in Finite Wing-AR8 at 'transitional' incidence of 8°, also indicated in twodimensional results but at the weak-jet incidence of 4°. For the application of 2d data to AR6, AR8, and ARIO, an assessment of 2d force results led to the analysis that the tests in the AAE's Low Turbulence Tunnel for 2d were under-predicting the damage effects at low incidence, and over-predicting at high incidences. This suggested therefore that Irwin's 2d results could not be used immediately to predict three-dimensional.

Any unexpected disruption to WDM (Wavelength Division Multiplexing) based optical networks which carry data traffic at tera-bit per second may result in a huge loss to its end-users and the carrier itself. Thus survivability has been well-recognized as one of the most important objectives in the design of optical Internet. This thesis proposes a novel survivable routing architecture for the optical Internet. We focus on a number of key issues that are essential to achieve the desired service scenarios, including the tasks of (a) minimizing the total number of wavelengths used for establishing working and protection paths in WDM networks; (b) minimizing the number of affected working paths in case of a link failure; (c) handling large scale WDM mesh networks; and (d) supporting both Quality of Service (QoS) and best-effort based working lightpaths. To implement the above objectives, a novel path based shared protection framework namely Group Shared protection (GSP) is proposed where the traffic matrix can be divided into multiple protection groups (PGs) based on specific grouping policy, and optimization is performed on these PGs. To the best of our knowledge this is the first work done in the area of group based WDM survivable routing approaches where not only the resource sharing is conducted among the PGs to achieve the best possible capacity efficiency, but also an integrated survivable routing framework is provided by incorporating the above objectives. Simulation results show the effectiveness of the proposed schemes.

Any unexpected disruption to WDM (Wavelength Division Multiplexing) based optical networks which carry data traffic at tera-bit per second may result in a huge loss to its end-users and the carrier itself. Thus survivability has been well-recognized as one of the most important objectives in the design of optical Internet. This thesis proposes a novel survivable routing architecture for the optical Internet. We focus on a number of key issues that are essential to achieve the desired service scenarios, including the tasks of (a) minimizing the total number of wavelengths used for establishing working and protection paths in WDM networks; (b) minimizing the number of affected working paths in case of a link failure; (c) handling large scale WDM mesh networks; and (d) supporting both Quality of Service (QoS) and best-effort based working lightpaths. To implement the above objectives, a novel path based shared protection framework namely Group Shared protection (GSP) is proposed where the traffic matrix can be divided into multiple protection groups (PGs) based on specific grouping policy, and optimization is performed on these PGs. To the best of our knowledge this is the first work done in the area of group based WDM survivable routing approaches where not only the resource sharing is conducted among the PGs to achieve the best possible capacity efficiency, but also an integrated survivable routing framework is provided by incorporating the above objectives. Simulation results show the effectiveness of the proposed schemes.

Made available in DSpace on 2016-12-12T20:22:52Z (GMT). No. of bitstreams: 1 Gustavo Andriolli S Cavalcanti.pdf: 1327760 bytes, checksum: bc2279bc162dd158d8e1d52a2a7df585 (MD5) Previous issue date: 2014-07-11 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Virtual infrastructures (VIs) sets of virtual machines interconnected by links and routers also virtual consolidated the dynamic provisioning of computing and communication resources and their services providers (InPs) face a challenge in choose the better approach to allocating and reserve these resources. Resource allocation (such as CPU, disk, memory, bandwidth) is a complex problem that needs to satisfy different goals: users expect to run their applications on survivable VIs, while InPs aim to maximize profits, minimize costs and reduce substrate fragmentation. However, there is a dichotomy between maximizing VI survivability, by sparsely allocating resources to decrease the impact of substrate failures, and minimizing substrate fragmentation, by co-locating VIs. In this context, we propose a mixed integer programming model to allocate resources considering the joint coordination of survivability and fragmentation. Experimental results show that it is possible to enhance VI survivability without significantly impacting substrate fragmentation. / Com a consolidação do provisionamento dinâmico de Infraestruturas Virtuais (IVs) - conjuntos de máquinas virtuais interconectadas por enlaces e roteadores também virtuais -, provedores de serviço (InPs) enfrentam um desafio na escolha da melhor abordagem para alocação e reserva de recursos computacionais e de comunicação. ´E fato que a alocação de recursos (como CPU, disco, memória, largura de banda) é um problema complexo que precisa satisfazer diferentes objetivos: usuários esperam executar suas aplicações em IVs eficientes e confiáveis, enquanto InPs objetivam maximizar lucros, minimizar custos e reduzir a fragmentação do substrato físico. Sobretudo, há uma dicotomia entre maximizar a confiabilidade de IVs, alocando recursos esparsos para diminuir o impacto de falhas no substrato, e minimizara fragmentação do substrato, co-alocando IVs. Nesse contexto, ´e proposto um modelo de programação inteira mista para alocar recursos considerando a coordenação conjunta de confiabilidade e fragmentação. Resultados experimentais mostram que é possível aprimorar a confiabilidade de IVs sem impactar significativamente na fragmentação do substrato.

Syftet med studien har varit att ur ett militärtekniskt överlevnadsperspektiv ta fram underlag över vilken verkansförmåga helikopter 16 behöver under ett transportuppdrag, i en nationell insats där hotet utgörs av mekaniserat infanteri. Studien har genomförts som en kvalitativ studie med ett visst kvantitativt inslag och baseras på data och fakta hämtad ur öppen litteratur samt genom intervjuer av uppdragsspecialister med erfarenhet och kunskap inom dörrskytte. Till hjälp har metodverktyget A´WOT-analys använts, vilken är en hybrid till SWOT-analysen. Syftet med A´WOT-analysen är att skilja ut de faktorer som behövs för verkan från helikopter 16 mot en definierad motståndare. Det samlade resultatet och sammanfattningen av studien är att helikopter 16 verkansförmåga behöver en omfattande uppgradering, om uppdrag som egen taktisk enhet skall kunna genomföras i en hotmiljö som utgörs av en kvalificerad motståndare. / The purpose of the study has been to investigate, from a military technical survival perspective, the effectiveness of helicopter 16 during a transport mission, in a national effort where the threat consists of a qualified opponent. The study has been conducted as a qualitative study with a certain quantitative element and based on data and facts obtained from open literature as well as interviews by mission specialists with experience and knowledge from door gunnery. As a help, the method tool A'WOT analysis have been used, which is a hybrid to the SWOT analysis. The purpose of the A'WOT analysis is to distinguish important factors for the effect from helicopter 16 against a defined opponent. The overall result and summary of the study is that helicopter 16 action ability needs a proper upgrade if assignments as a tactical unit can be carried out in a hot environment dictated by a qualified opponent.

The emergence of cloud computing has transformed the potential of robotics by enabling multi-robotic teams to fulfil complex tasks in the cloud. This paradigm is known as “cloud robotics” and relieves robots from hardware and software limitations, as large amounts of available resources and parallel computing capabilities are available in the cloud. The introduction of cloud-enabled robots alleviates the need for computationally intensive robots to be built, as many, if not all, of the CPU-intensive tasks can be offloaded into the cloud, resulting in multi-robots that require much less power, energy consumption and on-board processing units. While the benefits of cloud robotics are clearly evident and have resulted in an increase in interest among the scientific community, one of the biggest challenges of cloud robotics is the inherent communication challenges brought about by disconnections between the multi-robotic system and the cloud. The communication delays brought about by the cloud disconnection results in robots not being able to receive and transmit data to the physical cloud. The unavailability of these robotic services in certain instances could prove fatal in a heterogeneous environment that requires multi-robotic teams to assist with the saving of human lives. This niche area is relatively unexplored in the literature. This work serves to assist with the challenge of disconnection in cloud robotics by proposing a survivable cloud multi-robotics (SCMR) framework for heterogeneous environments. The SCMR framework leverages the combination of a virtual ad hoc network formed by the robot-to-robot communication and a physical cloud infrastructure formed by the robot-to-cloud communications. The Quality of Service (QoS) on the SCMR framework is tested and validated by determining the optimal energy utilization and Time of Response (ToR) on drivability analysis with and without cloud connection. The experimental results demonstrate that the proposed framework is feasible for current multi-robotic applications and shows the survivability aspect of the framework in instances of cloud disconnection. / School of Computing / M.Sc. (Computer Science)