Stability estimates with a priori bound for the inverse local Radon transform

We consider the inverse problem for the $2$-dimensional weighted local Radon transform $R_m[f]$, where $f$ is supported in $y\geq x^2$ and $R_m[f](\xi,\eta)=\int f(x, \xi x + \eta) m(\xi, \eta, x)\,\text{d} x$ is defined near $(\xi,\eta)=(0,0)$. For weight functions satisfying a certain differential equation we give weak estimates of $f$ in terms of $R_m[f]$ for functions $f$ that satisfies an a priori bound.Comment: 34 page

Sweden has effectively used bilateral co-operation with the US and other European states as an alternative to NATO membership.

Sweden is one of only a handful of EU countries which are not members of NATO. Jan Joel Andersson provides an overview of Swedish defence policy and assesses the potential for Sweden to use the EU as an alternative to NATO membership. He argues that the myth of the country’s policy of ‘armed neutrality’ during the Cold War is still a key obstacle to gaining public support for joining NATO. However in practice Sweden has effectively used informal bilateral co-operation with the US and other European states to ensure its security

The Race to the Bottom

The growing need to protect global shipping routes and the intensification of maritime territorial conflicts have led to a naval arms buildup around the world. Perhaps the most-cited example of this new focus on naval power is the increasing number of countries building or planning new aircraft carriers, but many analysts are more concerned about the proliferation of modern attack submarines. Often considered the ultimate weapon of naval warfare, submarines are versatile platforms able to attack surface ships, conduct antisubmarine war- fare (ASW), deploy mines, and, as they are increasingly equipped with missiles, attack land targets

Two protocols without periodicity for the global and preemptive scheduling problem of multi-mode real-time systems upon multiprocessor Platforms

We consider the problem of scheduling a multi-mode real-time system upon identical multiprocessor platforms. Since it is a multi-mode system, the system can change from one mode to another such that the current task set is replaced with a new task set. Ensuring that deadlines are met requires not only that a schedulability test is performed on tasks in each mode but also that (i) a protocol for transitioning from one mode to another is specified and (ii) a schedulability test for each transition is performed. We propose two protocols which ensure that all the expected requirements are met during every transition between every pair of operating modes of the system. Moreover, we prove the correctness of our proposed algorithms by extending the theory about the makespan determination problem

Kontemplativa Landskap

Människan har behov som går utöver de rent fysiska och sociala och kan förstås som en meningssökande varelse. I ett mer sekulariserat samhälle har landskapet kommit att spela en större roll för många människor i deras strävan efter att få utlopp för behov som traditionellt framförallt förknippats med religiositet. Utifrån dessa utgångspunkter undersöker uppsatsen hur landskapet kan utformas för att bidra till kontemplativa upplevelser och hur dessa uppkommer just i relation till landskapet. Vad som ska förstås som ”kontemplativa landskap” är inte uppenbart och uppsatsen försöker därför undersöka hur begreppet ska förstås genom att både, definiera vad kontemplation är, hur dessa upplevelser uppkommer och kan främjas. Samt genom att undersöka hur vår upplevelse och förståelse av landskapet blir till. Uppsatsen använder sig av framförallt arkitekturteori och estetisk teori med fenomenologiska utgångspunkter. Härigenom förstås landskapsupplevelsen som något som blir till genom ett kroppsligt möte där alla sinnen och mentala processer är involverade. Utifrån dessa perspektiv identifieras en konflikt mellan den traditionella förståelsen av kontemplation som något som innebär ett distanserade ifrån ”den materiella världen” och ett perspektiv som istället betraktar kontemplation som ett fördjupat deltagande i världen. Uppsatsen diskuterar hur den japanska trädgårdstraditionen präglas av ett förhållningsätt till tid och rum som kan berika förståelsen av kontemplativa upplevelser i mötet med landskapet. Genom en exempelstudie av Entsū-ji Templet i Kyoto konkretiseras resonemangen om hur det riktade fokuset, som kontemplationen innebär, kan åstadkommas genom sinnena och genom vår fysiska så väl som mentala rörelse i landskapet. Uppsatsen presenterar, med utgångspunkt i både den fenomenologiska teorin och exempelstudierna i Japan, en punktslista med kriterier som kan användas för att förstå ”deltagande kontemplativa” upplevelser av landskap. Listan är tänkt att både vara användbar som ett analysverktyg och som inspiration vid gestaltning.Man has needs that go beyond the purely physical and social and can be understood as a “meaning-seeking” creature. In a more secularized society, the landscape has come to play a greater role for many people in their quest to have an outlet for needs that are traditionally associated primarily with religiosity. Based on these points of departure, the paper examines how the landscape can be designed to contribute to contemplative experiences and how these arise in relation to the landscape. What should be understood as "contemplative landscape" is not obvious and the paper therefore tries to examine how the concept should be understood by both defining what contemplation is, how these experiences arise and can be promoted. And by examining how our experience and understanding of the landscape is created. The thesis uses mainly architectural theory and aesthetic theory with phenomenological starting points. Hereby the landscape experience is understood as something that is created by a bodily encounter where all the senses and mental processes are involved. From these perspectives, a conflict is identified between the traditional understanding of contemplation and something that means a distanced from the "material world" and a perspective that instead regards contemplation as an in-depth participation in the world.The paper discusses how the Japanese garden tradition is characterized by an attitude towards time and space that can enrich the understanding of contemplative experiences in the encounter with the landscape. Through an exemplary study of the Entsū-ji Temple in Kyoto, the reasoning on how the targeted focus that contemplation implies can be realized through the senses and through our physical as well as mental movement in the landscape. The essay presents, based on both the phenomenological theory and the example studies in Japan, a point list with criteria that can be used to understand "participatory contemplative" experiences of landscape. The list is intended to be both useful as an analysis tool and as inspiration for design

Slum i centrum : deltagande och radikal planering i Villa 31, Buenos Aires

Citizen participation has as a planning strategy, become increasingly enveloped and is today often described as a way to deepen democracy. At the same time, there is reason to question this rhetoric as many researchers argue that these strategies does not live up to what they promise. The aim of this paper is to understand how citizen participation work under the neoliberal scheme, focusing on issues of power and how this processes can be understood as legitimizing practices. A case study has been conducted in Villa 31, a centrally located and conflict-traded slum area in Buenos Aires. Critical theory regarding citizen participation and theories of radical planning constitutes the theoretical foundation. Two different types of civil dialogues are identified in the case, one of which represents a clear official dialogue process and the other has been conducted more informally. These separate processes illustrate both that dialogues can be seen as a tool for maintaining the status quo. But also how civil dialogues can act as a more progressive force when allowing it to take a more activistic form. The essay points out that it is important to identify how dialogue processes relate to residents' own self-organized spaces for participation in order to understand how these processes can be a way to empower marginalized groups.Medborgardeltagande har som planerings strategi kommit att bli allt mer omhuldat och beskrivs idag ofta som ett sätt att fördjupa demokratin. Samtidigt finns det skäl att ifrågasätta denna retorik då många forskare menar att dessa strategier inte lever upp till vad de utlovar. Målet med denna uppsats är att förstå hur medborgardialoger fungerar under den nyliberala ordningen, med ett fokus på frågor kring makt och hur medborgardialoger kan förstås som legitimerade praktiker. En fallstudie har genomförts i Villa 31, ett centralt beläget och konflikt omsusat slumområde i Buenos Aires. Kritisk teori kring medborgardialog och teorier kring ´radical planning´ utgör den teoretiska grunden. Två olika typer av medborgare dialoger identifieras i fallet, där den ena utgör en tydligt officiell dialog process och den andra har utformas mer informellt. Dessa skilda processer illustrerar både att dialoger kan ses som ett verktyg för att upprätthålla status quo. Men även hur medborgardialoger kan fungera som en mer progressiv kraft, då den tillåts ta en mer aktivistisk form. Uppsatsen pekar på att det är viktigt att identifiera hur dialog processer förhåller sig till boendes egna själv-organiserade rum för deltagande, för att kunna förstå hur dessa processer kan bli ett sätt att stärka marginaliserade grupper

Airborne Wind Energy Based on Dual Airfoils

The airborne wind energy (AWE) paradigm proposes to generate energy by flying a tethered airfoil across the wind flow at a high velocity. Although AWE enables flight in higher altitude and stronger wind layers, the extra drag generated by the tether motion imposes a significant limit to the overall system efficiency. To address this issue, two airfoils with a shared tether can reduce overall system drag. Although this technique may improve the efficiency of AWE systems, such improvement can only be achieved through properly balancing the system trajectories and parameters. This brief tackles that problem using optimal control. A generic procedure for modeling multiple-airfoil systems with equations of minimal complexity is proposed. A parametric study shows that at small and medium scales, dual-airfoil systems are significantly more efficient than single-airfoil systems, but they are less advantageous at very large scales

Influence of Hot Isostatic Pressing on the Hot Ductility of Cast Alloy 718: The Effect of Niobium and Minor Elements on the Liquation Mechanism

The influence of two hot isostatic pressing (HIP) treatments on liquation behavior was investigated and compared with regard to the extent of heat-affected zone liquation cracking in cast Alloy 718. The extent of liquation was seen to increase after HIP treatment at 1190 \ub0C due to solute changes caused by the homogenization of Nb, which contributed to extensive grain boundary melting. The HIP treatment at 1120 \ub0C exhibited lower liquation with contributions from particle liquation of the Laves phase and constitutional liquation of NbC carbides. This was also reflected in a lower ductility recovery temperature, with slower recovery for the former due to the extensive liquation. Interestingly, the nil ductility temperatures were both below the predicted equilibrium solidus of the alloy, which suggests that the ductility drop is related to liquation caused by solute segregation at the grain boundaries