The thesis is devoted to finding robust non-conflict paths in multi-agent path finding (MAPF). We propose several new techniques for the construction of these types of paths and describe their properties. We deal with the use of contingency planning and we create a tree plan for the agents where the specific path is chosen by the agents during the execution based on the current delay. Next we present an algorithm that increases robustness while maintaining the original length of the solution and we combine it with the previous approach. Then we will focus on the method of increasing robustness by changing the speed of agents. Finally we experimentally verify the applicability of these techniques on different types of graphs. We will show that all the proposed methods are significantly more robust than the classic solution and they also have certain advantages over previously known constructions of robust plans.

I Sverige och Finland sker idag ett kontinuerligt och växande arbete för att skapa ökad resiliens och för att mer effektivt kunna förebygga och hantera risker, sårbarheter och hot. Grannländerna har rätt likartade utgångspunkter på en rad områden men när det kommer till krisberedskap valde Finland en annan väg än Sverige under 1990-talets slut. De avvecklade inte sin omfattande försörjningsberedskap fullt ut som Sverige gjorde. Sedan 2017 har svenska myndigheter arbetat intensivt med återuppbyggnaden av det civila försvaret och den svenska livsmedelsberedskapen. Återuppbyggnaden har öppnat ett fönster av möjligheter att påverka hur livsmedelsberedskapen ska se ut, för parallellt har Sverige fördjupat samarbetet med Finland på en rad säkerhetsrelaterade områden. Under 2021 tecknades ett samarbetsavtal om krisberedskap, civilt försvar och räddningstjänst mellan länderna. Målet är att öka vår gemensamma förmåga att förebygga och hantera risker, sårbarheter och hot på både kort och lång sikt. Med hjälp av kvalitativ textanalys uppbackat av ett teoretiskt ramverk kopplat till hur en socioekologisk resiliens kan stärkas, har denna studie granskat de regeringsuppdrag som delats ut till de svenska myndigheterna tillsammans med två finska styrdokument som reglerar den finska livmedelsberedskapen. Därutöver har tre djupintervjuer genomförts med personer som jobbar nära livsmedelssystemet, två informanter från Sverige och en från Finland för att skapa ytterligare förståelse för livsmedelsberedskapens utmaningar och möjligheter. Studien kan konstatera att både den finska livsmedelsberedskapen och den svenska beredskapsplaneringen fokuserar i huvudsak på att öka robustheten i livsmedelssystemen och trygga handelsflöden men har en försiktig och inkrementell inställning till hur en transformering mot ett hållbart livsmedelssystem ska byggas. Följaktligen är beredskapsplaneringen inriktad på att hantera kortare störningar snarare än att hantera utdragna och mer komplexa störningar, som klimatförändringar. Riskhanteringen bör spegla de hot och sårbarheter som finns och även om en väluppbyggd robusthet kan motstå störningar idag föreslås livsmedelsberedskapen, liksom den övriga politiken utformas med målet att hämma de pådrivande orsakerna (risk drivers) som bidrar till den ökade sårbarheten, annars blir det förr eller senare svårt att upprätthålla beredskapen i systemet. / The two neighbours Sweden and Finland are constantly working to increase their resilience, and ability to prevent and manage risks, their vulnerabilities, and threats. The old neighbours share similar starting points in several areas, but when it comes to crisis preparedness, Finland chose another path than Sweden , as they did not entirely phase out their extensive security of supply stockpiles like Sweden did in the late 1990s. Though, since 2017, Swedish authorities have worked extensively with the reconstruction of the national civil defence and the Swedish food contingency planning. This development has opened a window of opportunity to influence what food contingency planning should look like because parallel to this development, Sweden has deepened its cooperation with Finland in several security-related areas. In 2021, a co-operation agreement was signed on crisis preparedness, civil defence and search and rescue services between the countries. The main objective is to increase our common ability to prevent and manage risks, vulnerabilities, and threats in both the short and long term.  Using qualitative text analysis backed by a theoretical framework linked to how a socio-ecological resilience can be strengthened, this study has examined the government orders regarding rebuilding the food contingency planning, that were handed out to the Swedish authorities. This paper also examines two Finnish policy documents regulating the Finnish food contingency planning. In addition, three in-depth interviews were conducted with people connected to the food supply system. Two informants from Sweden and one from Finland, to create a further understanding of the challenges and opportunities of rebuilding the Swedish food contingency planning.  This paper can conclude that both the Finnish food contingency planning and the upcoming Swedish food contingency planning focus mainly on increasing the robustness of the food system and to secure trade flows but are rather cautious and suggest incremental steps in transforming towards a sustainable food system. Thus, the current contingency planning is focused on dealing with shorter disruptions in supply flows rather than dealing with protracted and more complex disruptions, such as climate change. It seems reasonable that risk management should be aimed at dealing with the threats and vulnerabilities that exist. Even if a robust food supply strategy can withstand disruptions today, food contingency planning, is suggested to be designed with a dual purpose to reduce the effects from the risk drivers that contribute to the increased vulnerability, otherwise it will become increasingly difficult to maintain the food supply system.

This dissertation presents a new approach for identifying, assessing, mitigating, and managing the risks of failure in complex systems. It describes the paradigm commonly used today to explain such failures and proposes an alternative paradigm that expands the lens for viewing failures to include alternative theories derived from modern theories of physics. Further, it describes the foundation for each paradigm and illustrates how the paradigms may be applied to a particular system failure. Today, system failure commonly is analyzed using a paradigm grounded in classical or Newtonian physics. This branch of science embraces the principles of reductionism, cause and effect, and determinism. Reductionism is used to dissect the system failure into its fundamental elements. The principle of cause and effect links the actions that led to the failure to the consequences that result. Analysts use determinism to establish the linear link from one event to another to form the chain that reveals the path from cause to consequence. As a result, each failure has a single cause and a single consequence. An alternative paradigm, labeled contemporary, incorporates the Newtonian foundation of the classical paradigm, but it does not accept the principles as inviolate. Instead, this contemporary paradigm adopts the principles found in the theories of relativity, quantum mechanics, chaos, and complexity. These theories hold that any analysis of the failure is affected by the frame of reference of the observer. Causes may create non-linear effects and these effects may not be observable directly. In this paradigm, there are assumed to be multiple causes for any system failure. Each cause contributes to the failure to a degree that may not be measurable using techniques of classical physics. The failure itself generates multiple consequences that may be remote in place or time from the site of the failure, and which may affect multiple individuals and organizations. Further, these consequences, are not inevitable, but may be altered by actions taken prior to and responses taken after the occurrence of the failure. The classical and contemporary paradigms are applied using a single embedded case study, the failure of the space shuttle Challenger. Sources, including literature and popular press articles published prior to and after the failure and NASA documents are reviewed to determine the utility of each paradigm. These reviews are supplemented by interviews with individuals involved in the failure and the official investigations that followed. This dissertation demonstrates that a combination of the classical and contemporary paradigms provides a more complete, and more accurate, picture of system failure. This combination links the non-deterministic elements of system failure analysis to the more conventional, deterministic theories. This new framework recognizes that the complete prevention of failure cannot be achieved; instead it makes provisions for preparing for and responding to system failure. / Ph. D.

Ypatingų aplinkybių (nenumatytų atvejų) planai reikalingi tam, kad oro eismo paslaugos niekada nenutrūktų, oro eismas išliktų saugus ir jo valdymas būtų kuo efektyvesnis (pvz., būtų kuo didesnis oro erdvės pralaidumas). Atsitikus bet kokiai nenumatytai situacijai, pagal jos scenarijų sukuriamas veiksmų planas, kuriuo privaloma vadovautis ypatingomis aplinkybėmis. Pagrindinis tikslas kuriant NAP tai skrydžių saugos užtikrinimas. Tai yra didžiausias prioritetas šiandieninėje aviacijoje. Oro navigacijos paslaugų teikėjo ypatingų aplinkybių (nenumatytų atvejų) planai palyginus su Eurokontrolės ir ICAO rekomendacijomis neatitinka visų reikalavimų. Kai kuriose situacijose panaudoti veiksmų planai nepilnai atitinka realybę arba tiesiog yra nepakankamai aiškūs, todėl juos būtina tobulinti. Darbą sudaro keturios dalys, įvadas, analitinė – metodinė dalis, tiriamoji dalis bei išvados ir siūlymai, literatūros sąrašas. / Contingency planning is necessary so that air navigation service would never be interrupted and safe air traffic services would be provided at any time Whenever a non-standard situation occurs the contingency plan is prepared. The main purpose of contingency planning is both to prevent the services from inefficiency and to decrease the impact of a disaster by increasing safety. Safety in aviation is priority number one, so it is necessary to be ready for any possible situation which could interrupt ANSP’s work. When analyzed and compared with ICAO and EUROCONTROL recommendations ANSP‘s contingency plans do not fully meet the requirements and some changes should be implemented as quickly as possible. It is necessary to have an adequate operational plan for any unexpected situation. Structure: introduction, three parts of work: theoretical and analysis, investigation, conclusions and suggestions, a list of references.

The thesis analyses how the system of oil and fuel storage was created, and applied in Sweden during the Cold War. The investigation focuses on the period 1938-1998 and considers the vital role of fossil fuel during a period when Sweden declared neutrality and independence. This period also includes a phase of divestment of some of the state-owned stores. The project is partly based on original research in several archives including the Swedish Geological Survey, the War Archives of Sweden, the archive of the city of Stockholm, and relevant state agencies. Fuel was a means to security of supply, and how current policies interacted, as well as the extent to which it was perceived as a vital part of the nation’s current security politics. In particular, how the storage of oil, on a large scale, demanded adjustments of the physical Scandinavian bedrock, which in turn required new technology is examined. The study follows the forthcoming of both an organisation and a new set of knowledge illustrating how the practice of storing oil, in itself an unstable fluid changing characteristics over time, created a surrounding social network. The thesis also reviews the environmental awareness and ensuing concerns relating to the stores. The oil storage created a whole range of new specialists and experts, as well as academic fields, which all converged around the storage of oil. The long-term storage required regulations and monitoring, resulting in creation of new areas of expertise both within the companies obliged to store oil, and also within relevant state agencies. In addition, supervising authorities developed, typically governmental agencies, of which one was also assigned to dismantling the stores. The thesis discusses the political climate motivating the dismantling of the stores relating to contingency planning and civil defence, tracing the discourse until today when stores are now being re-activated.

No description available.

Approved for public release, distribution is unlimited / A capabilities-based approach to contingency planning offers important opportunities to strengthen both Homeland Defense and Homeland Security. The Department of Defense (DOD) and the Department of Homeland Security (DHS) have already begun moving beyond traditional threat-based and scenario-based planning methodologies toward a more capabilities-based approach, but require embracing this concept more in order to counter challenges in developing contingency plans against current threats to the US Homeland. Additionally, given the critical responsibilities of state and local governments in Homeland Security, this planning approach might be applied far beyond the Federal government. This thesis examines ways that a specialized capabilities-based planning process might be applied to Homeland Defense and Homeland Security, and applies the proposed methodology to two case studies: the US Navy Component of US Northern Command and the New York City Fire Department. / Lieutenant Colonel, United States Army

There is growing interest in commercial aircraft formation flight as a means of reducing both airspace congestion and the carbon footprint of air transportation. Wake vortex surfing has been researched extensively and proven to have significant fuel-saving benefits, however, commercial air transportation has yet to take advantage of these formation benefits due to understandable safety concerns. The realization of these formations requires serious consideration of formation contingencies and safety during closer-in maneuvering of large commercial aircraft. Formation contingency scenarios are much more complex than those of individual aircraft and have not yet been studied in depth. This thesis investigates the utility of optimization modeling in providing insight into generation of aircraft escape paths for formation contingency planning. Three high-altitude commercial aircraft formation scenarios are presented; formation join, formation emergency exit, and formation escape. The model-generated paths are compared with pilot-generated escape plans using the author’s pilot expertise. The model results compare well with pilot intuition and are useful in presenting solutions not previously considered, in evaluating separation requirements for improvement of escape path planning and in confirming the viability of the pilot-generated plans. The novel optimization model formulation presented in this thesis is the first model shown to be capable of generating escape paths comparable to pilot- generated escape plans and is also the first to incorporate avoidance of persistent and drifting wake turbulence within the formation.

Recent advancements in telecommunications have brought new tools about in the field of robotics, with offloading emerging as one of the most significant developments. Hence, computationally expensive tasks are performed on a server in the cloud instead of on the mobile robot, reducing processing costs in robots and enhancing their efficiency. However, one of the major challenges of offloading robot control is to maintain functional safety even when the connection with the server is interrupted. To mitigate these connectivity losses, an optimization-based method has been developed to compute an environment-dependent contingency plan. This plan is sent from the cloud to the robot together with the corresponding control command. The planner takes into account the current map, based on all sensor data collected up to the time of optimization, and the nominal trajectory to provide a sequence of safe control commands. Assuming that in the absence of connectivity, all detected objects will move at a constant speed. Therefore, the contingency plan would be executed on the robot only when connectivity to the cloud is lost, without making use of subsequent sensor data in the robot’s on-board processor. Thus, through the proposed method, it is possible to maximize the movement time of the mobile robot in case of loss of connectivity with the cloud controller without compromising any safety constraints. In this context, two different approaches have been designed based on the possibility of deviating from the nominal trajectory. In the first, called “path following”, the mobile robot is constrained to stay on the reference path, but can vary its speed, performing a safety brake when there is a risk of collision. In contrast, in “trajectory following”, deviation is allowed by trying to prolong the point at which the velocity is reduced. The evaluation shows that the optimal approach depends on the application for which the mobile robot will be used. Furthermore, these approaches do not overload the network bandwidth, since contingency plans can be optimized by parameterizing the velocity sequences or by reducing the sending rate through event-triggered sending. / De senaste framstegen inom telekommunikation har introducerat nya verktyg inom robotikens område, där offloading är en av de mest relevanta. Således utförs beäkningsintensiva uppgifter på en server i molnet istället för på den mobila roboten, vilket minskar bearbetningskostnaderna för roboter och ökar deras effektivitet. En av de största utmaningarna med att offloada robotstyrning är dock att bibehålla funktionell säkerhet även när anslutningen till fjärrservern bryts. För att hantera sådana avbrott, har vi utvecklat en optimeringsbaserad metod för att beräkna en reservplan, anpassad till miljön runt roboten. Denna plan skickas från molnet till roboten tillsammans med varje styrkommando. Planeraren beaktar den aktuella kartan, baserad på all sensordata som samlats in fram till nu, och den nominella banan och beräknar en säker reservplan i form av en sekvens av styrkommandon. För säkerhets skull antar planeraren att i händelse av ett avbrott, kommer alla hinder i kartan att närma sig roboten med en konstant hastighet. Det gör det säkert att exekvera reservplanen om anslutningen till molnet går förlorad, utan att använda efterföljande sensordata för att uppdatera kartan. Den föreslagna metoden gör det alltså möjligt att maximera tiden som den mobila roboten kan fortsätta köra vid förlust av anslutning till molnservern, utan att göra avkall på säkerheten. I detta projekt har vi utformat två olika planeringsmetoder, som skiljer sig vad gäller möjligheten att avvika från den nominella banan. I den första, kallad “path following”, tillåts inte roboten att avvika från referensbanan och utför därför en säkerhetsbromsning när det finns risk för kollision. I den andra, kallad “trajectory following”, tillåts roboten avvika från referensbanan, genom att försöka fördröja det ögonblick då roboten behöver bromsa. Utvärderingen visar att vilken metod som är bäst, beror på tillämpningen som den mobila roboten används för. Dessutom överbelastar dessa tillvägagångssätt inte nätverksbandbredden, eftersom beredskapsplaner kan optimeras genom att parameterisera hastighetssekvenser eller genom att minska överföringshastigheten. / Los recientes avances en las telecomunicaciones han traído consigo nuevas herramientas en la robótica, siendo el offloading una de los desarrollos más significativos. Así, las tareas computacionalmente más costosas se realizan en un servidor en la nube en lugar de en el robot móvil, reduciendo los costos de procesamiento en el robot y mejorando su eficiencia. Sin embargo, uno de los mayores desafíos del offloading de control de robots es mantener la seguridad funcional incluso cuando la conexión con el servidor se interrumpe. Con el fin de mitigar las pérdidas de conectividad, se ha desarrollado un método basado en optimizacion que calcula un plan de contingencia dependiente del entorno. Este plan se envía desde la nube al robot junto con el comando de control correspondiente. El planificador tiene en cuenta el mapa del entorno actual, basado en todos los datos del sensor recopilados hasta el momento de la optimización, y la trayectoria nominal para proporcionar una secuencia de comandos de control seguros. En este sentido, el planificador asume que, en ausencia de conectividad, todos los objetos detectados se aproximarán al robot a una velocidad constante. Este plan de contingencia se ejecutaría en el robot solo cuando se pierde la conectividad con la nube, sin hacer uso de datos de sensor posteriores en el procesador a bordo del robot. Por lo tanto, mediante el método propuesto, se logra maximizar el tiempo de movimiento del robot móvil en caso de pérdida de conectividad con el controlador en la nube sin sacrificar las restricciones de seguridad. En este contexto, dos enfoques distintos según la posibilidad de desviarse o no de la trayectoria nominal han sido diseñados. En el primero, denominado “path following”, no se permite que se desvíe de la referencia, aplicando un frenado de seguridad cuando existe riesgo de colisión. En cambio, en “trajectory following”, se permite la desviación para tratar de prolongar el momento en el que se reduce la velocidad. La evaluación muestra que el enfoque óptimo depende de la aplicación para la cual se utilizará el robot móvil. Además, estos enfoques no sobrecargan el ancho de banda de la red, ya que los planes de contingencia pueden optimizarse parametrizando las secuencias de velocidad o reduciendo la velocidad de envío.