Pour faire face à la complexité croissante des systèmes de télécommunications sans fil, il est nécessaire de développer des systèmes RF (Radiofréquence) plus performants et agiles. Dans ce contexte, des matériaux à changement d’état, ou SCM (State Change Material), déjà utilisés dans le développement des futures générations de mémoires non-volatiles (PCRAM, CBRAM), ont récemment été évalués pour réaliser des commutateurs RF. Parmi ces SCM, les PCM (matériaux à changement de phase) semblent ainsi être une solution particulièrement attractive pour réaliser des composants RF permettant l’obtention de circuits reconfigurables, rapides, miniatures et intégrables sur des circuits CMOS.En lien avec la stratégie du LETI / DCOS (Département COmposants Silicium) et en s’appuyant sur une analyse fine de la physique des matériaux à changement d’état, la thèse aura pour objectif de développer une nouvelle filière technologique de composants RF en rupture à base de SCM qui permettront de concevoir de nouvelles architectures de circuits RF innovants et reconfigurables. / As wireless telecommunication systems complexity continues to increase, there is a need to develop RF systems with higher performances and agility. In this context, SCM (State Change Material), already used to develop the next generation of non-volatile memory (PCRAM, CBRAM), were recently evaluated to realize RF switches. Among these SCM, PCM (Phase Change Material) are an attractive option to realize miniature and high speed reconfigurable RF components that could be easily integrated with CMOS circuits.In line with the LETI / DCOS (Silicon Components Division) strategy, PhD will aim to develop a disruptive RF components technology based on SCM that will allow designing innovative and reconfigurable FEM (Front End Module) circuits.

Human disruption of climate, habitat, and ignition has altered the behavior of wildland fire at local to continental scales. In many regions, novel fire regimes are emerging that threaten to exceed the capacity for local management to protect human wellbeing and ecosystem function. Simultaneous changes in climate, species composition, and fire management have resulted in extreme fire behavior in many regions. For the Western United States, the emerging novel fire regime consists of more frequent, severe, and intense wildfires, with annual area burned by wildfire having doubled and high-severity wildfire area having increased 8-fold since the 1980s. The impacts of these increasing stresses in the Great Basin is especially pressing when combined with the many years of historically poor resource management. Here we complete a literature review of changing wildfire regimes globally (chapter 1) and a study of how the abiotic and biotic aspects of aquatic ecosystems stabilize after a megafire in the western United States (chapter 2).

There is an ever increasing demand of electricity and to meet this demand, installation of new transmission and distribution lines is required. This task requires a significant investment and consent from the respective authorities. An alternative is to utilize maximum capability of the existing lines. Static line ratings are based on a conservative estimate, which means that on most occasions, the actual capacity of lines is much higher than the static line ratings. In order to provide a solution to this problem, this thesis introduces an approach that has been developed to utilize real time weather conditions, conductor sag data and the actual line loading of the conductor from PMU to provide dynamic line ratings for active distribution networks. The application has been developed in LabVIEW environment which provides a user friendly front panel where real-time ampacity can be seen as a waveform while being compared to the actual line loading.  The developed application has been tested on the reference grid created for IDE4L project. The ampacity calculation method introduced here makes use of real-time data available through a real-time simulator in SmarTS lab at KTH, Sweden. / Det är ett ökande behov av elektricitet och för att möta detta behövet, installation av nya transmission och distributionsledningar behövs. Denna utbyggnad kräver ett stort engagemang och förståelse från ansvariga grupper. Ett alternativ är att utnyttja max-kapaciteten på redan befintliga ledningar. Installerade ledningar har räknats på ett konservativt sätt, vilket innebär att det vid vissa tillfällen går att öka belastingen på på dessa. För att ge en lösning på detta problem, introducerar den här avhandlingen en metod för att använda realtids-väderdata, tabeller för ledningarnas utvidgning och realtids-belastningsdata från PMU för att framställa dynamisk data för aktiva distributions-nätverk. Applikationen har utvecklas i LabVIEW-miljön som har ett användarvänligt GUI, där “Real-time ampacity” kan ses som en vågform medans den jämförs mot den faktiska belastningen på ledningen.  Den utvecklade appliktionen har testats på referens-miljön som skapts för IDE4L projektet. “Ampacity calculation metoden” som introduceras här använder sig av realtidsdata som görs tillgänglig igenom en realtids-simulator i SmarTSlab på Kungliga Tekniska Högskolan i Sverige.

<p>Traditional robots and soft robots have often been treated as two distinct options for design, a dichotomy between stiffness and compliance. In reality, they compose two ends of a spectrum, and there has been research to soften traditional robots and stiffen soft robots. The latter option has seen a large variety of techniques to actively and selectively create stiffness in an otherwise soft robot. The common disadvantage concerning all of them is the need for constant energy input. In this work, a first-of-its-kind method for a permanent stiffness of a growing robot is explored and tested.</p> <p>First, I show the qualitative and quantitative testing of the stiffening method, expanding insulation foam, both by itself and when applied to a vine robot. With this knowledge, I investigate a design to apply the foam to a growing robot as it moves, taking advantage of the properties of the foam to coat a vine robot as needed. This selective foam placement unlocks various unique capabilities like adhering to its environment, imparting & resisting large forces, and isolating sections of its body. Finally, these traits are highlighted in three demonstrations, proving the efficacy of this unique method as well as affirming the utility of permanently stiffening a soft robot. In the future, the work in this thesis can help open the way for permanent deployable robotic structures and soft robots in roles more traditionally used for rigid robots.</p>

Current design models, approaches and theories are highly fragmented, have seldom been compared with one another, and rarely attempted to be consolidated. Novelty is a measure of creativity of engineering products and positively influences product success. Using physical laws and effects for designing can improve the chances of creativity but they cannot be used directly owing to their inadequate current representations. It is important to address activities, outcomes, requirements and solutions in designing. Conceptual design is an early phase in engineering design and needs to be supported better. A systematic approach for designing often increases effectiveness and efficiency. Thus, the broad objective of this thesis is to develop and validate a comprehensive understanding of how designing occurs during the conceptual phase of engineering design, and to support variety and novelty of designs during this phase. The approach followed is: (a) formulate and validate an understanding of novelty and its relationships to the designing constructs, in current designing, and(b)develop and validate a support, founded on the current designing, to improve novelty. The understanding and the support are addressed, respectively, through an integrated model and a systematic framework for designing; the model and the framework comprise activities, outcomes(including laws and effects), requirements and solutions. An integrated model of designing, GEMS of SAPPhIRE as req-sol is developed by combining activities(Generate, Evaluate, Modify, Select– GEMS), outcomes (State change, Action, Parts, Phenomenon, Input, oRgans, Effect–SAPPhIRE), requirements (req) and solutions (sol), identified from a comprehensive survey of existing design models and approaches. Validation of SAPPhIRE model with existing systems indicates that the model can be used to describe analysis and synthesis, both of which together constitute designing. Validation of the integrated model using existing videos of design sessions, to check if all its constructs are naturally used in designing, reveals that:(a) all the constructs are naturally used;(b) not all the outcomes are explored with equal intensity;(c) while high numbers of action and parts are observed, only low numbers of phenomenon, effects and organs are found. Empirical study using another set of design sessions to study the relationships between novelty and the outcomes reveals that novelty of a concept space depends on the variety of the concept space, which in turn depends on the variety of the idea space explored. Novelty and variety of a concept space also depend on the number of outcomes explored at each abstraction level. Thus, phenomena and effects are also vital for variety and novelty. Based on the above, GEMS of SAPPhIRE as req-sol framework for designing is proposed. The framework is divided into: Requirements Exploration Stage(RES) and Solutions Exploration Stage(SES). In RES and SES, requirements and solutions respectively at all the abstraction levels including SAPPhIRE are generated, evaluated, modified and selected. The framework supports task clarification, conceptual and early embodiment phases of designing, and provides process knowledge. Comparison of the framework against existing design models, theories and approaches reveals that:(a) not all existing models, theories and approaches address activities, outcomes, requirements and solutions together;(b) those that address all these constructs together do not make a distinction between requirements and solutions; and(c) no model or approach explicitly addresses novelty. The usability of the framework and Idea-inspire is assessed by applying them in an industrial project for designing novel concepts of lunar vehicle mobility system. The use of this combined support enables identification of critical requirements, development of a large variety of ideas and concepts. One of these concepts is physically and virtually modelled, and tested, and is found to satisfy all the requirements. A catalogue of physical laws and effects is developed using SAPPhIRE model to provide assistance to designers, especially for phenomena, effects and organs. Observations found during this development are reported. A comparative validation of the framework and the catalogue for their support to design for variety and novelty is done using comparative observational studies. Results from the observational studies reveal that the variety and the novelty of concept space improve with the use of the framework, or with the frame work and the catalogue, as compared to variety and novelty with no support.