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  • Harlin, Anna
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Arkitektur.
    Malongen: a mimic of a rock2019Independent thesis Advanced level (professional degree), 20 poäng / 30 hpOppgave
    Abstract [en]

    Malongen consists of two volumes containing housing, a gallery, and a restaurant. The design language of the base comes from a 3D scan of the rock 30 meters north of the plot. The buildings are a design interaction to explore the tension between the historical mountain cut and a design interaction. With a digital imitation of the rock the buildings intend to mimic the surrounding area. The rock, that is the historical imprint of the place, is now translated into buildingelements, as a result of my manipulation of the file. This project has investigated how we can create a contemporary buidling that refer to a historical site and keep telling a story about time.

  • Grundmark, Anna
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Arkitektur.
    ”VART ÄR VI PÅ VÄG?” / WHERE ARE WE GOING?2019Independent thesis Advanced level (professional degree), 20 poäng / 30 hpOppgave
    Abstract [en]

    In the middle of the nineteenth century, the train came to Sweden. It has been just over 150 years and a lot has happened. With the train and its station came more then just a means of transportation, it turned Sweden from a developing country into one of the most modern. In the small Swedish cities and on the countryside, the stations became a central node, a meeting point and a place to gather. The train passed through previously isolated areas where the stations became not only just that but also a window towards the rest of the world. This project is a study of the Swedish train station and a humble proposal on how to treat them, what to do with them and when to do it (now).

  • Svensson, Daniella
    et al.
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Fastigheter och byggande.
    Ribbefjord, Beatrice
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Fastigheter och byggande.
    Ekonomiska fördelar med en grön premie: En studie av ekonomiska drivkrafter på den gröna obligationsmarknaden i Sverige2019Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [sv]

    Syftet med rapporten är att undersöka och analysera motiv och ekonomiska incitament bakom fastighetssektorns deltagande på den gröna obligationsmarknaden i Sverige. Rapporten diskuterar huruvida en grön premie eller ett Green bond premium, även kallat Greenium, existerar samt hur stort detta är. Greenium är skillnaden mellan räntan på en grön obligation och en traditionell obligation. Vidare analyseras anledningar till att ett Greenium skulle uppstå. En diskussion förs huruvida det är mer ekonomiskt lönsamt att köpa gröna obligationer i jämförelse med traditionella obligationer. År 2007 utfärdade Världsbanken den första gröna obligationen i världen i samarbete med SEB. Sedan gröna obligationens uppkomst har marknaden vuxit till ett globalt värde på över 300 miljarder dollar. Vasakronan utfärdade världens första gröna företagsobligation 2013, efter det fick marknaden i Sverige sitt största uppsving och sedan dess har marknaden vuxit kraftigt. Gröna obligationer har samma ekonomiska egenskaper som traditionella obligationer men skillnaden är att intäkterna från gröna obligationer måste finansiera miljö- eller klimatvänliga projekt. Gröna obligationer medför en del risker för aktiva aktörer. Dessa risker är bland annat anseenderisk, greenwashing och asymmetrisk information. Med tanke på den enorma påverkan företag idag har på miljön är det lämpligt att dessa tar ansvar för sina utsläpp och andra negativa externa effekter. Genom konceptet Corporate Social Responsibility har företag tagit mer ansvar för hur de påverkar samhället ur såväl ett ekonomiskt, miljömässigt samt socialt perspektiv. Genom CSR har gröna obligationer blivit populärt och i synnerhet på fastighetsmarknaden där ambitionen kring hållbarhet vuxit kraftigt de senare åren. Sammanfattningsvis kan det konstateras att ett greenium finns men att det är svåruppskattat. Enligt intervjuade personer inom fastighetsbranschen kan greenium antas vara -4 till -5 baspunkter och enligt vetenskapliga artiklar antas det vara cirka -2 baspunkter. En baspunkt motsvarar en hundradels procent. Att greenium uppstår beror på investerares stora efterfrågan och emittenters låga utbud på gröna obligationer i dagsläget. Fastighetsbranschen är ledande på den gröna obligationsmarknaden i Sverige och detta antas bero på branschens tidiga modifiering av gröna obligationer samt sektorns välutvecklade certifieringssystem av hållbara byggnader. I framtiden kan den gröna obligationsmarknaden antas växa och utvecklas inom såväl andra branscher som andra länder.

  • Nielsen, Carl
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Fastigheter och byggande.
    Osäkerhet och risk vid bedömning av restvärdet för Samhällsfastigheter: En fallstudie av hur fastighetsvärderare hanterar restvärdet för samhällsfastigheter2019Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [sv]

    I marknadsrapporter går att läsa att samhällsfastigheter är en lågriskplacering där investerare söker säker hamn när det börjar blåsa. I Catella Property Forecast (2019) bedöms samhällsfastigheter som låg risk med medel-till-hög avkastning. Den underliggande efterfrågan på samhällsfastigheter i Sverige drivs av den demografiska utvecklingen och framgent behövs stora investeringar för att möta behovet bland landets kommuner och landsting. Hos investerarkollegiet har samhällsfastigheter seglat upp som ett alltmer populärt segment och i en marknadsrapport från Pangea Property Partners kommuniceras att samhällsfastigheter är den mest eftertraktade produkten bland institutionella investerare på fastighetsmarknaden i Sverige (Pangea Institutional Outlook, 2019). På grund av dess beskaffenhet bedöms risk och osäkerhet för investeringar i samhällsfastigheter som relativt låg under kontraktsperioden där ekonomiskt stabila hyresgäster säkerställer ett kassaflöde under långa hyresförhållanden. Hyresgästrisken och vakansrisken är i princip obefintlig under de långa hyreskontraktens löptid. Dock behäftas fastigheterna alltid, likt alla fastigheter, med en viss risk som kan härledas till exempelvis teknisk risk och miljörisk. Utöver dessa tillkommer även politisk risk samt juridiska risker. Specifikt för samhällsfastigheter är att de, per definition, är specialanpassade för verksamheten vilket kraftigt begränsar dess alternativa användning. Alla ovan nämnda parametrar ska speglas i en marknadsvärdesbedömning utförd av en registrerad värderare. Marknadsvärdesbedömningar är centrala i beslutsfattandet vilket föranleder att det är av största vikt att de är rättvisande. Då investerare känner komfort för de förhållanden som råder under löptiden för de långa avtalen är det intressant att granska synen på dessa fastigheter då kontrakten har löpt ut. Syftet med denna fallstudie är att genomlysa hur restvärdet för samhällsfastigheter bedöms av värderare med hänsyn till osäkerhet och risk. Värdering av fastigheter sker vanligen med kassaflödesmetoden som bygger på att framtida driftnetton under en given kalkylperiod diskonteras. Till detta värde adderas ett diskonterat restvärde som ska motsvara fastighetens värde vid slutet av kalkylperioden vilket ofta sammanfaller med att hyreskontraktet löper ut. Metoden bygger till stor del på prognostisering av framtiden. Följaktligen är värderingar behäftade med osäkerhet. Hur riskerna och osäkerheterna behandlas i värderingen kommer att framgå av resultatet. Studien visar att värderanas syn på restvärdesrisken för samhällsfastigheter är nästintill enhetlig och bygger ur teoretisk synvinkel på en objektiv bedömning av värderingsobjektets egenskaper och förutsättningar vid kalkylperiodens slut. Här bedöms ingående parametrar så som geografiskt läge, fastighetens kvalitet och standard men även politisk risk och vad byggnaden är anpassad till i dagsläget. Det framkommer även hur centralt sambandet mellan initial direktavkastning, exit yield och marknadens avkastningskrav är i bedömningen. Studien visar även att värderare bedömer att investerare inte fullt ut tar hänsyn till restvärdesrisken på de nivåer som transaktioner sker till i dagsläget.

  • Myhrer, Samuel
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Fastigheter och byggande.
    Effekten av infrastruktursatsningar på bostadspriser i närliggande områden: En studie om Nacka stad. Prisutveckling i Jarlaberg och Storängen2019Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [sv]

    Nacka kommun genomgår stora förändringar av projektet Nacka stad som innebär nya bostäder, kommersiella fastigheter och tunnelbanestationer. När ett område inom en kommun förändras har det visats att detta ger en effekt angående bostadspriserna i andra närliggande områden. Studiens syfte blir därav att se vilken effekt infrastruktursatsningar har på bostadspriser i Jarlaberg och Storängen i och med projektet Nacka stad. Detta har lett till frågeställningen; Vilken effekt kommer projektet Nacka stad ha på bostadspriserna i Jarlberg och Storängen? Studien grundas på teorier angående fastighetsvärdering, pristeori, lokaliseringsteori och restidsvärdering. Två typer av datainsamling har använts; Booli och en enkätundersökning. Utöver detta har även en litteraturstudie gjorts. Resultatet visar på att Nacka stad kommer att medföra en positiv effekt på bostadspriserna i Jarlaberg. Angående Storängen anses inte tillräckligt med relevant data och information innehas för att kunna dra några slutsatser.

  • Jillersberg, Madeleine
    et al.
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Fastigheter och byggande.
    Denlert, Adam
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Fastigheter och byggande.
    Finansiering inom bostadsrättsektorn: En studie om en alternativ finansieringsmodell2019Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [sv]

    Priserna på den svenska bostadsmarknaden har stigit ovanligt mycket de senaste åren. En konsekvens av detta är att allt fler får det svårare att ta sig in på bostadsmarknaden och köpa sin första bostad. Inte minst förstagångsköpare som har svårt att spara ihop till den höga insatsen som ofta krävs eller bli beviljade lån hos bankerna. En alternativ finansieringsmodell har skapats för att göra det lättare för dessa personer att ta sig in på bostadsmarknaden. Denna modell bygger på att det är föreningen som ska stå för den större delen av lånet, istället för köparen. Denna uppsats syftar till att jämföra skillnaderna mellan en bostadsrätt som finansieras på det traditionella sättet och en bostadsrätt som finansieras genom den alternativa finasnieringsmodellen. Den modell som kommer att analyseras i denna studie heter BRF 2.0 och har lanserats av Well Fastigheter. De riktar sig främst till unga personer, därav har en enkätundersökning utförts för att få en inblick i vilken kunskap en förstagångsköpare har inom detta område. Enkäten är utformad som ett kunskapstest som behandlar några av de ekonomiska aspekter i ett bostadsköp som kan vara bra att känna till. Därefter utfördes en intervju med en representant på ett av företagen som har tagit fram denna alternativa investeringsmodell, nå en djupare förståelse för upplägget. Resultaten indikerar att förstagångsköpare besitter bristande kunskap kring bostadsköp för att ur ett ekonomiskt perspektiv kunna ta de mest fördelaktiga besluten. Studien pekar på vikten av att förstagångsköpare själva behöver ta ansvar för att läsa på inom ämnet så de blir medvetna om vilken kunskap de redan besitter och vilken kunskap de behöver lära. Ett problem som nämns i studien är att dessa personer inte alltid är medvetna om vilket område de saknar kunskap inom och kommer därför inte hämta in denna information. Vid detta problem krävs det att högre instanser kliver in och påverkar. Som ett förslag nämns att regering eller utbildningsväsende arbetar vidare med dessa frågor.

  • Göthlin, Sanna
    et al.
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Fastigheter och byggande.
    Rigogianis, Nicole
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Fastigheter och byggande.
    IFRS16 - Leases2019Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [sv]

    Från och med den 1 januari 2019 infördes den nya internationella redovisningsstandarden IFRS 16 - Leases och ersätte den gamla standarden IAS 17 - Leases. Klassificeringen av leasingavtal mellan operationella och finansiella enligt IAS 17 - Leases har kritiserats för att ha skapat ett incitament för företag att redovisa leasingavtal som operationella och således undvika att kapitalisera kontrakten i balansräkningen som en leasingtillgång respektive leasingskuld. För att hantera den problematik och informationsasymmetri som uppstod inledde IASB och FASB ett projekt som resulterade i den nya standarden IFRS 16 - Leases.Att belysa i den nya standarden IFRS 16 är att leasegivare inte påverkas i samma utsträckning som leasetagare. Redovisningen för leasegivare påminner om det tidigare regelverket, IAS 17, och därav medför inte förändringen några större skillnader. För leasetagare innebär den nya standarden att bolaget måste identifiera sina leasingkontrakt som löper över tolv månader eller avser ett värde över 5 000 USD när tillgången var ny. Klassificeringen av operationella och finansiella leasingavtal kommer således att upphöra för leasetagare men kvarstå för leasegivare.Syftet med uppsatsen är att genom en kvalitativ ansats med intervjuer i kombination med kvantitativa undersökningar av kvartalsrapporter studera de förändringar som IFRS 16 medför på fastighetsföretags balans- respektive resultaträkning. Uppsatsen kommer även att klarlägga vilka finansiella nyckeltal som kommit att påverkas av IFRS 16 i bolagens finansiella rapport för första kvartalet 2019 och avslutningsvis undersöka om den nya standarden kan komma att påverka värderingen av tomträttsfastigheter. Uppsatsens syfte mynnar ut i två frågeställningar formulerade under avsnitt 1.3 Syfte.Utifrån de intervjuer som genomförts med representanter från tre olika verksamhetsområden har relevanta slutsatser framställts och respektive frågeställning kunnat besvarats med 

    säkerhet. Övergången till IFRS 16 kommer att påverka nyckeltal som bland annat belåningsgrad, soliditet och räntetäckningsgrad. För fastighetsbolag är det främst leasingkontrakt i form av tomträtter som är av betydelse då fastighetsbolagen i dessa leasingkontrakt är leasetagare och således påverkas av den förändrade redovisningen. Bruttoresultatet kommer även att påverkas då fastighetsbolagens driftnetto ökar till följd av att avgiften för tomträtten, tomträttsavgälden, flyttas från att vara en kostnad som belastar driftnettot, till att vara en finansiell post i form av ränta.Avslutningsvis har konstaterats att IFRS 16 inte har någon större påverkan på fastighetsbolag, varken på dess finansiella rapportering eller specifika nyckeltal. Bolagen kan relativt enkelt tillämpa IFRS 16 genom en förenklad metod, vilka många bolag valt att göra. Det har dock framkommit att det inte har varit lika enkelt att tolka standarden och hur upplysningar om IFRS 16 ska ske konkret i kvartalsrapporterna. Kvartalsrapporterna som släppts första kvartalet 2019 har därav haft en spridning i tydlighet så väl som utformning. En generell uppfattning från flera respondenter har varit att IFRS 16 medför extra arbete i bolagens redovisning men leder dessvärre inte till ökad transparens, vilket var grundidén till varför den nya standarden togs fram från början. Således kan även konstateras att IFRS 16 inte fullständigt uppnår sitt syfte att öka transparensen.

  • Yilmaz, Rusen
    et al.
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Fastigheter och byggande.
    Edlund, Viktor
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Fastigheter och byggande.
    Hur påverkas direktavkastningskravet på kontorsfastigheter av makroekonomiskaförändringar?: En kvantitativ studie av sambandet mellan direktavkastningskrav och makroekonomiska variabler2019Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [sv]

    Den svenska kontorsmarknaden har under senare år drivits mot rekordhöga hyror och lågadirektavkastningskrav. Drivkraften i utvecklingen har varit gynnsamma makroekonomiskaförhållanden med bland annat negativ reporänta. Denna studie syftar till att undersöka ivilken grad utvecklingen av direktavkastningskrav i tre svenska storstäder, Stockholm,Göteborg och Malmö kan förklaras av makroekonomiska förändringar. Intressant är även hurde olika städerna förhåller sig till varandra och utvecklingen i ekonomin. Frågeställningensätts i ett mer generellt sammanhang, där marknads- och fastighetspecifika faktorerutelämnas.Med stöd av empiriska studier och ekonomiska teorier, som bland annat 4Q-modellen,angrips frågeställningen genom ett urval av makrovariabler, bearbetning av data ochgrundläggande statistiska beräkningar. Dem utvalda makrovariabler är: KPI, Reporänta,Statsobligationer 10 år, BNP, Arbetslöshet och OMXS30. Korrelationsberäkningar och linjäraregressionsmodeller är centrala verktyg i det kvantitativa arbetet. De statistiskaberäkningarna utförs både med och utan tidsförskjutningar på direktavkastningskravet motmakrovariabler. På så vis beaktas fastighetsmarknadens tröghet och cykliska natur.Resultatet, som ligger i linje med tidigare studier, visar att valda makroekonomiska variableroftast inte är tillräckliga för att förklara rörelsen i direktavkastningskravet. Inte heller påvisasnågon påtaglig skillnad städerna emellan. Resultatet vittnar om värdet av mängd data ochurvalet av oberoende variabler vid en regressionsanalys. Däremot påvisas ett tydligtsamband mellan utvecklingen av direktavkastningskravet och de utvalda makrovariablerna.

  • Fiedorowicz, Sandra
    et al.
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Fastigheter och byggande.
    Eklöf, Ellinore
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Fastigheter och byggande.
    Bostadsföretagens uthyrningspolicy: En jämförelsestudie mellan bostadsföretag i Stockholmsområdet2019Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [sv]

    I denna studie har vi undersökt olika bostadsföretags uthyrningspolicy inom Stockholmsområdet samt hur pass lättillgänglig information är om bostadssökningsprocessen via deras hemsidor. Vi vill undersöka om det finns någon skillnad mellan hur bostadsföretag förmedlar sina grundkrav och på vilken nivå dessa ligger för en bostadssökande. Hur påverkar detta samhället och i synnerhet hur påverkar det oss som studenter? Finns det även en skillnad mellan kommunala och privata bostadsföretag i Stockholmsområdet?För att finna svar på frågeställningarna undersökte vi 13 olika privata- och kommunala bostadsföretag; HSB, Ikano Bostad, Wallenstam, Byggvesta, Rikshem, Willhem, HEBA Fastigheter AB, Svenska Bostäder, Stockholmshem, Familjebostäder, Micasa Fastigheter, Stadsholmen samt Stockholms Studentbostäder. Vi studerade hur företagens respektive uthyrningspolicy var utformade på deras hemsidor samt hur lättillgängligt det var att hitta viss väsentlig information som bostadssökande. Detta blev en jämförelse företagen sinsemellan vilket gav oss en överskådlig bild på vad som bör förbättras inom området.Det visade sig finnas en betydlig skillnad mellan privata- och kommunala bostadsföretag där den största skillnaden var att privata bostadsföretag reglerar sina uthyrningspolicy hårdare än vad de kommunala gör. Alla hemsidor var mer eller mindre dåligt utformade gällande tillgänglighet och språkmöjligheter. Vi behandlade även våra studiefrågor utifrån ett hållbarhetsperspektiv då det anses vara betydande för ett fortsatt fungerande samhälle.Avslutningsvis gavs rekommendationer för bostadsföretagen för att förbättra sina hemsidor och policys. Störst vikt bör läggas på att förbättra möjligheten för alla individer på bostadsmarknaden för att få en bostad. Samt att förbättra bostadsföretagens hemsidor i fråga om transparens och språkmöjligheter, för att utveckla bostadsmarknaden ur ett socialt och teknologiskt perspektiv.

  • Paul, Sourav
    et al.
    KTH, Skolan för industriell teknik och management (ITM).
    Sarkar, Saranik
    KTH, Skolan för industriell teknik och management (ITM).
    Integration of Cryogenic Machining Technologies in Advance Manufacturing Systems2019Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Conventional cutting fluids are an absolute necessity in today’s manufacturing domain, butthey are a polluting and non-sustainable part of modern manufacturing processes. These conventional cutting fluids can be replaced by cryogenic cooling, which is an innovative and sustainable method which has been successfully implemented to produce aerospace products and have shown great success and great quality of finished products. But the implementation is the main obstruction as the volume of production in aerospace and automotive components is quite vast and implementation of cryogenic may pose an obstruction in maintaining the production flow. This leaves us with a large unexplored area for research specially in the implementation of the system in the existing system, which canhelp us get a seamless transition from conventional to cryogenic cooling. Some of the notable points that there is a need to investigate before one can go ahead with the implementationare factory layout, chip removal, raining of personal, safety, monitoring system, cost, time, implementation and integration, maintenance, source placement, mass scale supply and quality. In the first part of this work, a deep literature study has been done to know all the aspects of cryogenics and its implementation and factors that must be considered. In the second a discussion about the target industries has been made where use of cryogenic cooling has been considered. Also, a small discussion about the existing companies that provide this system has also been discussed. The room for improvisation is very large, and a lot of physical testing needs to be conducted before it can be successfully implemented.

  • Rickfält, Tea
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik.
    From linear to circular water management: A case study of Sandön/Sandhamn2019Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Even though water is essential for all living beings, the way humans manage water is traditionally linear; extract, use and dispose. By doing so, many cities have partly disconnected themselves from the environment by existing beyond the local hydrologic system. A circular water system, which reuse water within the technical water system, has the potential to improve the status of the environment and reduce pressure on existing water resources. As such it is an approach that receives increasing attention. This study aims to investigate how a circular water management approach can reduce fresh waterconsumption and decrease the human pressure on water resources through a case study of the island Sandön/Sandhamn in the Stockholm archipelago. A literature overview which identifies circular water management strategies have been performed along with a situation analysis of Sandön. To identify and assess different options of reuse the framework of strategic environmental assessment have been used. In the case of Sandön, which have a high water-demand peak during summer, decentralised solutions for one of the largest water consumers is recommended. Reclaiming water from the wastewater treatment plant to, among other, flush toilets would also be favourable. Private homeowners could also beneficially implement reuse by flushing toilets with water used to wash hands or from showers. The study shows that circular water management provides an opportunity to reduce pressure on water resources and use them in a more efficient manner. The most crucial criteria for circular water measures success is public acceptance. It is also important to thoroughly map local conditions to identify the best suitable reuse measures as each location is unique.

  • Friefeldt, William
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Lärande.
    Gullberg, Philip
    KTH, Skolan för industriell teknik och management (ITM), Lärande.
    Nätcoaching som ett komplement till lösningsförslag: En undersökning av en ny digital lärmiljö genomundersökande relation2019Independent thesis Advanced level (professional degree), 20 poäng / 30 hpOppgave
    Abstract [sv]

    Den tekniska utvecklingen har varit storskalig i världen och människors vardagsliv harändrats mycket det senaste seklet. I kontrast till detta har den svenska skolan inte sett sammahastiga tekniska utveckling. Samtidigt visar resultat från PISA att elevers resultat i matematiksjunker. Här identifieras två problem som måste lösas. Därför syftade denna undersökningtill att underlätta elevers matematikstudier genom att skapa en ny digital lärmiljö. Lärmiljönkom att kombinera matematiska lösningsförslag med nätcoaching. Det gjordes med hjälp avdet digitala läromedlet Mathleaks och lärplattformen TalkMath. Därefter analysera hur entill-en nätcoaching fungerade i denna nya lärmiljö. Undersökningen syftade även ta reda påhur elever uppfattar lärmiljön och om den kan vara ett komplement till lösningsförslag.Lärmiljön skapades med grund i pedagogiska teorier såsom Vygotskijs sociokulturellaperspektiv, teorier om coaching, synkron kommunikation samt teorier om en-till-ennätcoaching. Två metoder användes för att samla denna data. För det första sparades allakonversationer automatiskt i en databas. För det andra så användes en enkät för att samlaelevernas uppfattning av lärmiljön. Ramverket Undersökande relation användes för attanalysera alla konversationerna mellan elev och coach. Studenterna valdes ut från en svenskgymnasieskola där en av författarna jobbar, eleverna var i åldrarna 15-18 år. Resultatenindikerade att denna nya lärmiljö var ett bra komplement till lösningsförslag. Det drogs ävenslutsatsen att lärmiljön hjälpte elevers kognitiva progression. Undersökningen visar att endigital lärmiljö kan vara ett bra komplement för elever som studerar matematik medlösningsförslag.

  • Occhinero, Marco
    KTH, Skolan för industriell teknik och management (ITM).
    Hydrogen production from automotive waste via integrated plasma gasification and water gas shift.2019Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    The growing amount of landfilled waste could pose a problem in many parts of the world due to the scarcity of landfilling space and environmental threats. In particular, automotive shredder residue (ASR) waste, a by-product of the dismantling of End of Life Vehicles (ELVs), has been proven to represent an issue in particular in the EU, where countries are struggling to compel to the directives that regulate this type of waste. At the same time, interest for hydrogen production methods is growing in the industries due to the advancement in fuel-cell technology for transportation and for power production.

    This study aims to investigate the performance of an integrated plasma gasification-hydrogen production system powered by ASR waste through the simulation of the process in ASPEN Plus. The investigation is focused on the potential for hydrogen production from ASR waste in terms of energy efficiency and quantity of hydrogen produced. The integrated system consists of an updraft plasma gasifier to generate clean syngas with high hydrogen content, a water gas shift reactor to furtherly enrich the gas of hydrogen content and a PSA unit to extract the hydrogen from the gas stream. The plasma gasification section of the model has been divided into four sub-systems that are drying, pyrolysis, char combustion and gasification, and melting. These four sub-systems are used to model the plasma gasification using the equilibrium method. On the other hand, the water gas shift reactor and the PSA unit have been modeled around experimental data. A Mass and Energy balance has been produced to understand the mass and energy flows within the system. The results show that the system is able to produce 238,5 kg/h of pure hydrogen from a feedstock of 2231 kg/h of ASR waste mixed with 89,2 kg/h of coke and 30 kg/h of limestone, achieving a 48% energy efficiency. Thus, the integrated system can achieve the production of pure hydrogen. The parameter study on the ER shows that hydrogen production and energy efficiency are higher at lower ER. On the other hand, increasing the SBR, while increasing the hydrogen content in the syngas, does not lead to higher hydrogen production at the system's output, causing a detrimental effect on energy efficiency. The findings of the study imply that ASR waste has the potential for hydrogen production when using a suitable treatment process.

  • Sverrisdóttir, Sunna Mjöll
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik.
    Stream Restorationand Mitigation of Nitrogen in the Hyporheic zone: Interpretation of tracer tests from Tullstorps brook2019Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Streams and rivers have been modified in the past centuries for agricultural purposes. The Baltic Sea suffers from problems regarding eutrophication. Regulations of point-sources have decreased nutrient levels, but for a scattered source of nutrient pollution, streams are important. One way of mitigating nitrogen is with coupled denitrification and nitrification processes when stream water is transported through flow paths in the hyporheic zone, an area in the stream sediments where groundwater and stream water mix. Tullstorps brook is an agricultural stream that flows into the Baltic Sea. It has had problems with high nutrient loads and poor water quality and has therefore been restored. The fieldwork in this project was conducted in Tullstorps brook in May 2019, where Rhodamine WT (RWT) tracer test and Hydraulic Conductivity (HC) measurements were done in 3 reaches, and compared to similar fieldwork since before restorations, during the summer of 2015. Two reaches in an agricultural setting that have been restored, Reach 4 and Reach 6, were measured, as well as a control reach, Reach 5, which is in a natural setting. The tracer tests indicated a significant decrease in the velocity in remediated reaches. The results of exchange velocity between the stream flow and the hyporheic zone suggest an increase after remediation of the reaches and the residence time seems to be decreasing simultaneously. When comparing the hydraulic characteristics, different stream flow during measurements was considered in a qualitative manner. The results of HC measurements show a decrease from 2015 to 2019 in the remediated reaches. In Reach 4 it decreased from 1.20E-03 m/s to 5.0E-4 m/s and in Reach 6, HC decreased from 7.70E-04 m/s before remediations to 5.6E-04 m/s after remediation actions. All the measurements have uncertainties, especially since homogeneity is assumed to some extent and the natural environment will always be heterogeneous.

  • Zeidler, Jacob
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Lättkonstruktioner.
    Conceptual Design Study of a Foil-Trailer to AUV 62-AT2019Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    The Swedish Navy has been using the AUV62-AT for submarine hunting training successfully for a while and it has been found that the biggest drawback is the transport which is very resource draining. The Swedish Defence Materiel Administration was given the task to solve this and a hydrofoiling-trailer was seen as a potential solution. This thesis will present the design process of the foil-trailer as well as issues found and how theses were mitigated, to produce a viable design. To develop the final design both current use of hydrofoil vessels and further adaptions needed for this applications were investigated. The project was done in collaboration with Simon Källerfelt Korall, who has during the project investigated in detail the foil-trailer’s roll stability, presents this in "The development of a foiling trailer for transport of the AUV62-AT"[1], which deals with how the experimental- and model results lines up. The result is a final design of a foil-trailer which is constituted of several sub-systems that has been found to improve the overall concept. It was concluded that the concept was viable and if further developed it can be used as a great method of saving time when deploying the AUV62-AT.

  • Dettmann, Aaron
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Lättkonstruktioner.
    Loosely coupled, modular framework for linear static aeroelastic analyses2019Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    A computational framework for linear static aeroelastic analyses is presented. The overall aeroelasticity model is applicable to conceptual aircraft design studies and other low-fidelity aero-structural analyses. A partitioned approach is used, i. e. separate solvers for aerodynamics and structure analyses are coupled in a suitable way, together forming a model for aeroelastic simulations. Aerodynamics are modelled using the vortexlattice method (VLM), a simple computational fluid dynamics (CFD) model based on potential flow. The structure is represented by a three-dimensional (3D) Euler-Bernoulli beam model in a finite element method (FEM) formulation. A particular focus was put on the modularity and loose coupling of aforementioned models. The core of the aeroelastic framework was abstracted, such that it does not depend on any specific details of the underlying aerodynamics and structure modules. The final aeroelasticity model constitutes independent software tools for the VLM and the beam FEM, as well as a framework enabling the aeroelastic coupling. These different tools have been developed as part of this thesis work. A wind tunnel experiment with a simple wing model is presented as a validation test case. An aero-structural analysis of a fully elastic unmanned aerial vehicle (UAV) (OptiMale) is described and results are compared with an existing higherfidelity study.

  • Ankarsköld-Flück, Kevin
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Lättkonstruktioner.
    Wiskman, Erik
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Lättkonstruktioner.
    Development of a motion platform for the G1X radar2019Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    The Giraffe 1X is a mobile short range 3D radar from Saab used for example to detect threats and create protection in a ground based air defence system. It can also be used on naval platforms for air and surface surveillance. During the development of the radar, the system needs to be tested for both sea and mobile land applications. The most convenient place for testing is on the roof of Saab’s facility in Gothenburg. There elevators can raise the radar to the roof giving an excellent view of for example Landvetter airport and the sea. To aid future verification experiments of the radar system, this project was started in order to develop and construct a motion platform used to simulate sea- and vehicle motions. During a six month period at Saab, the work of the project was started with a thorough research of motions platforms to conduct preliminary concept studies. Furthermore the concepts were drawn as 3D-CAD models in Creo Parametric in order to visualise the different solutions and present them for suppliers. The report also covers the assembly of the produced parts, together with the development of a user interface to control the motion platform.

    Lastly, the result of product development is a two-degree of freedom (DOF) motion platform influenced by the gyroscopic gimbal concept. The G1X radar is mounted on a gimbal platform which is made out of two aluminium frames, whereas the outer frame rotates around an horizontal axis while the inner frame rotates around a transversely mounted horizontal axis mounted on the outer frame. Each aluminium frame is attached to a link arm which is mounted on a motor that is used to tilt the frame. The platform can be tilted _ 22 o in pitch and _ 22 o in roll. The gimbal is supported by a steel structure to allow ground clearance and to raise the radar to a comfortable working height.

  • Busseti, Gabriele
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Lättkonstruktioner.
    Modal and Fatigue Analysis of the Stratotimer2019Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Fatigue analysis of the printed circuit boards (PCBs) of an avionic instrument has been analyzed. The natural frequency and transmissibility has been estimated through analytical approach and finite element approach with Solid- Works and experimentally. Fatigue analysis damage has been obtained with three methods: Steinberg Stress approach, Steinberg Relative Displacement approach and Dirlik method. The analysis indicates that the solder that holds the CPU on the control unit is critical for the fatigue life. The results show that each method is far from the critical CDI value of 0:7 and therefore the design could be optimized.

  • Wehtje, Ernst
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Rymdteknik.
    Development of miniaturized fill and drain system for propellant tanks on small satellites2019Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [sv]

    Under de senaste åren har rymdindustrin förändrats markant av bland annat inflödet av privat finansiering och tillgängligheten av ny teknologi, vilket har resulterat i att mindre och billigare satelliter finns på marknaden. GomSpace Sweden, som är en del av GomSpace Group, är en aktör på denna marknad och utvecklar framdrivningssystem för mindre satelliter, så kallade CubeSats. En av deras miniatyriserade produkter är ett framdrivningssystem av kall gas, som passar för 3-unit CubeSats. Med dagens design kan bränsletanken fyllas genom en ingångsport men endast tömmas genom munstyckena, vilket skapar flertalet problem. Detta arbete avser att utveckla en lösning på dessa problem och skapa ett fullständigt fyllnings- och tömningssystem för GomSpace produkt. En konceptuell lösning av ett fyllnings- och tömningsverktyg utvecklades, för att sedan designas och slutligen tillverkas. Verktyget testades, och resultaten uppfyllde de initialt ställda kravspecifikationerna. Efter fler utförda tester uppstod möjligheter till förbättringar vilket ledde till att en andra digital version av verktyget utvecklades. Ett förslag till en mergenerell lösning för fyllnings- och tömningssystem utvecklades också, vilket kan användas som en modul i framtida utvecklingsprocesser av små framdrivningssystem. Sammanfattningsvis visar detta arbete en lösning på problemet med fyllnings- och tömningssystemet av det nuvarande framdrivningssystemet för 3-unit CubeSats. Ett verktyg både tillverkades och testades med framgång. En förbättrad version av verktyget, som minskar riskerna för skador och slitage samt förenklar användningen, skapades som en digital modell. Slutligen, designades en generell lösning för fyllnings- och tömningssystem, vilket skulle kunna användas i flertalet av GomSpace’ framtida produkter och därmed minska bådekostnader och tid för produktutveckling.

  • Söderlund, Johanna
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Marina system.
    A study of risk management for serie produced vessels, in relation to the IMO risk perspective2019Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    The International Maritime Organization, IMO, aims to at a larger extent build their work in relation to and around risk management. It is therefore here investigated how IMO standards comply with industry risk management processes. The IMO risk perspective used in this study is the Formal Safety Assessment, FSA. The FSA was created to evaluate and compare new regulations in regards to cost and administrative or legislative burden and is a risk management methodology, which goal is to improve maritime safety. The FSA uses risk analysis and cost benefit assessment, and covers both technical and operational issues.

    By comparing the IMO risk perspective with industry risk management processes, and analysing the practical use of the FSA by applying it to three maritime accidents the goal with this report is to find similarities and differences of the two perspectives and present possible carryovers from industry risk approaches to the IMO risk perspective.

    It was found that the IMO risk perspective, here represented by the FSA, does overall comply with industry risk management processes. The main difference is that general industry risk management processes focuses on all phases of the development and use of a vessel, from the concept phase to the operation phase but the FSA focuses mainly on the operative perspective of the design phase and the operation phase. The largest deficiency of the FSA is the non-existing demands on safety culture which is found to be a requirement when doing a successful risk management assessment. If IMO is considering the FSA as their main risk management method to be used, it is important that requirements on safety management is added.

  • Miao, Tianlei
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Marina system.
    Generation of a full-envelope hydrodynamic database for hydrobatic AUVs: Combining numerical, semi-empirical methods to calculate AUV hydrodynamic coefficients2019Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    The next generation of Autonomous Underwater Vehicles (AUV) can impact our observation of the world. The flight simulation and full-envelope hydrodynamics modeling can improve the performance of AUVs in terms of control, navigation and positioning. In order to achieve agile maneuverability, a more accurate database of full-envelope hydrodynamic coefficients is supposed to be generated.

    Two semi-empirical methods, Jorgensen and DATCOM, and two numerical method, Computational Fluid Dynamics (CFD) and XFLR5 are used to push the boundaries of hydrodynamic coefficients: lift, drag and moment coefficients for flight-style AUVs at the Swedish Maritime Robotics Center (SMaRC). A comparison of different approaches and tools, and an analysis of the most appropriate approaches for different regions of a defined maneuver has been conducted in this thesis. A data confidence level was proposed as a way to estimate the accuracy of the data and a structured database was built in terms of data confidence level. Different components of the AUV such as the hull body and wings were analyzed separately. The new database is input to a 3DOF Simulink model and the 6DOF SMaRC hydrobatics simulator for flight dynamics simulations. Simulations show that the new database has a good applicability.

  • Cirillo, Giovanni
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Rymdteknik.
    Space Surveillance and Tracking Tool: Implementation and Test of New Methods​2019Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    In March 2019 the number of artificial objects bigger than 1 mm in orbit around the Earth is estimated to be more than 170 millions. Only a small fraction of them (0.03%) is catalogued. An impact of an operational satellite with one of these debris can damage the satellite and undermine its mission. So it is important to catalogue as many objects as possible in order to reduce the risk of a collisions. This is done by using the software tool Space Object Observations and Kalman Filtering (SPOOK), developed in Airbus Defence and Space in Friedrichshafen. The goal of this Master Thesis was to create newfunctionalities to this tool and improve the existing ones. In particular three main goals have been accomplished:

    • a new model for the lighting ratio has been built to take into account the occultation of the Sun due to a covering body (for example the Earth or the Moon) and itsinfluence on the solar radiation pressure, necessary to have a good model for orbit propagation;

    • a tracklet building algorithm has been built to distinguish different tracklets (consecutive observations of the same object along its orbit) as a starting point for the association of different measurements belonging to the same object at distant epochs, necessary to update a catalogue of space objects;

    • a model to take into account the process noise has been improved giving some suggestion on how to tune the different parameters for different kinds of orbit.

     

  • Chan, Charlotte
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Lättkonstruktioner.
    Compaction Simulation for Prepreg-AutoclaveManufacturing: Improvements and Simplifications of Two Compaction Simulation Methodologies2019Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    In a competitive market such as the aerospace industry, the use of manufacturing process simulation is vital to decrease time and cost of tooling and process development. In the autoclave process, to obtain an uniform part with no void, it is crucial to understand the compaction phenomenon. Through the last decades, compaction simulation methodologies have been developed but only rather simple geometry and/or small parts have been studied. At Airbus Helicopters Deutschland, compaction simulation methodology needs to be able to predict outcomes of rather large and complex helicopter parts such as the final thickness, porosity, wrinkles, thickness deviation, etc. In the two existing Airbus Helicopters Deutschland simulation methodologies, the main problems are the complexity of the simulation process, high computational costs and substantial set-up for rather simple parts. The research presented in this Master thesis aims at providing improvements and optimisations of the two simulations. A comparison of the two methods is also performed in terms of applicability, accuracy, set-up time and computational cost to assess which method should be favoured depending on the problem. Samples previously built at Airbus or during this thesis are used for the simulations’ calibration and validation.

    For the first method based on the soil approach, parameters such as the autoclave cycle length, the shear stiffness of the fibres, pore pressure boundary condition, number of contacts, mesh size and radius discretisation are investigated. This method is capable of predicting’ accurately the final thickness and the thickness distribution behaviour for flat and curved parts. However, at lower consolidation pressures, the accuracy decreases. Furthermore, this simulation methodology requires high computational and set-up times. During the calibration of the method, CPU and setup times are reduced by using smaller model and coarser mesh while still achieving a correct result.

    For the second methodology based on membrane elements while neglecting flow effects, the contact modelling is calibrated: the contact stiffness is correctly altered to fit the thickness variation during the manufacturing process. Calibration is done for flat parts. However, wrinkles start to form in the curved part model where no such defect was observed in the samples. This issue needs to be investigated first to continue the simulation calibration. The method shows accurate results for each pressure cycle with lower computational cost and faster set-up than the first method.

    In addition, wrinkles can be visualized directly in the simulation and core material such as honeycomb and foam sandwich cores can be taken into account. This method looks quite promising but needs further investigation.

  • Berhouni, Ilyès
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Flygdynamik.
    Flow transition prediction approaches evaluated on a single-aisle type aircraft2019Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Nowadays, as the demand for fuel efficiency is increasing and the manufacturing techniques improved to allow the design of laminar wings, the laminar concepts are being revived and studied, and seen as one of the most promising techniques to reduce skin friction and hence the overall drag of the airframe. In order to predict the kind of benefits that could be obtained from such concepts, computational fluid dynamics (CFD) computations can now be carried out but it is necessary to be able to predict flow transition from laminar to turbulent around the lifting surfaces of the aircraft, such as the wing and the horizontal tail plane. Such capability has been developed in the last years by the French Aerospace Laboratory (ONERA) with their CFD code elsA, and by the German Aerospace Center (DLR) with their CFD code Tau. These two codes are widely used in Airbus in their CFD campaigns, and this study aims to assess the capability of the different approaches to predict transition and the benefits from laminar flow in the overall drag. The methods used, the limitations and the suggestions for further improvement of the codes will be detailed in this paper.

  • Charpigny, Noé
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Rymdteknik.
    An Executable System Model for Behavioural Analyses of the LISA Mission2019Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    This master thesis report presents the modelling process of key elements of the Laser Interferometer Space Antenna mission (LISA mission) in a Modelbased systems engineering (MBSE) approach with SysML (Systems Modeling Language). The model implements a selected set of functions of the mission through executable graphical representations, called diagrams. It is shown how such diagrams can benefit the mission, by comparing this mean of information exchange to the traditional text- based systems engineering. The model represents the mission structure and behaviour through a system of nested layers. The deeper the layer is, the more it gives details on a system part. Each layer can be seen from different point of views, either focusing on the structure, the behaviour, or the performance of related system part.

  • Abrahamsson, Erik
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Marina system.
    En övergripande studie av undervattensdockning med obemannade farkoster i ubåt A262019Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [sv]

    I den här rapporten behandlas ett Systems Engineering arbete där en undersökning har utförts på möjligheten att docka en autonom undervattensfarkost med den nya generationens ubåt A26. I arbetet har fokus legat på de tidiga stegen inom Systems Engeineering disciplinen. En litteraturstudie på befintlig forskning och arbete inom området har utförts för att kartlägga idag möjliga tekniska lösningar. Intressenter har identifierats och personer med nyckelbefattningarinom sitt respektive område har intervjuats för att kunna sammanställa en behovsbild. Utifrån behoven har förmågor som systemet behöver möta kartlagts. I syfte att underlätta analysen av dockningssystemet har en definition samt en zonuppdelning av dockningsförfarandets olika faser utförts. En beskrivning av olika tekniker för undervattenskommunikation redovisas och diskuteras. En utvärdering och riskanalys av ett dockningssystem har utförts för att belysa de olika kommunikationsteknikernas för- och nackdelar under ett dockningsförfarande.Slutligen har två mekaniska system för slutfasen i en dockning jämförts mot varandra.

  • Disputas: 2019-11-07 13:00 F3, Stockholm
    Åsberg, Per
    KTH, Skolan för industriell teknik och management (ITM), Industriell ekonomi och organisation (Inst.).
    Brand Architecture from Above: Understanding the Customer Disconnect2019Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Global business is transforming. Information technology in general, and the Internet specifically, has globalized business and empowered the consumer with more information and choice than ever before. Consequently, academic research into brand portfolios and brand architecture is faced with new challenges to reflect this changing reality.

    Traditional research into brand portfolio management and its structural embodiment using brand architecture has approached these concepts from the perceptive of the brand owner/company. For instance, the portfolio has been mapped based on legal ownership of brands, which has been criticized as being a too narrow approach that exclude key contributors of the portfolio’s collective brand equity. Even in the cases where partner brands are acknowledged as part of the portfolio, their inclusion is often based on the revenue stream they represent or their link in the distribution chain instead of association. Brand architecture research has therefor focused on structural representations based on hierarchical trees created within the walls of the company itself, without necessarily investigating if the intended structure works as expected.

    The missing ingredient in this halting logic is the perceptions of the market in which the portfolio and its architecture operates. Associations and transfer of brand equity is dependent on a concept’s mental perception in the minds of consumers. An endorsement that does not get noticed by the target market is a mirage in the minds of marketing managers, and an historical collaboration that was cancelled years ago may still influence the brand portfolio today by means of association in consumer memory.

    The research presented in this thesis extends current theory in brand portfolio management and brand architecture to directly include the consumer perspective. This thesis re-classifies the portfolio and architecture concept as perceptual constructs whose efficiency is determined by the mental alignment between company representatives as the creators of the intended meaning and customers as the interpreters, or even co-creators, of the same. Study results presented indicate significant misalignment not only between stakeholder groups as a collective, but also between individuals within each group – even for brand managers working together on the same portfolio day after day. Current hierarchical models for representing brand architecture are extended using the perceptual dimension as well as a layer accounting for the openness of the portfolio, and a new brand portfolio model segregating brands based on the degree of perceptual inclusion in the portfolio is presented.

    This introduction of the perceptual dimension into both brand portfolio management and brand architecture represents a new way to view these abstract concepts, a conceptual idea that has ripple effects into areas such as brand equity transfer, brand alliances, and portfolio risk management.

  • Liu, Lida
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Kommunikationssystem, CoS.
    Hardware-Efficient WDM/SDM Network: Smart Resource Allocation with SDN Controller2019Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Optical networking has been developing for decades and wavelength-division multiplexing (WDM) is the main technology used to carry signals in fiber-optical communication systems. However, its development has slowed because it is approaching the Shannon limit of nonlinear fiber transmission. Researchers are looking for multi dimensional multiplexing. Space-division multiplexing (SDM) is an ideal way to scale network capacities. The capacity of WDM/SDM network could be expanded to several times the capacity of WDM network but the active hardware devices may also increase by several times.

    This project aims to answer a practical question: How to construct a WDM/SDM network with less hardware resource? There is no mature research about WDM/SDM network yet. Therefore, the problem can be divided into two parts: (1) how to build a WDM/SDM network and (2) how to allocate resource and compute routes in such a network to minimize hardware resources.

    First, this thesis proposes a WDM/SDM node which has bypass connections between different fibers and architecture on demand (AoD) to effectively decrease the number of active hardware devices within the node. Then, two types of networks were constructed: one with bypass connections in each node and another one without any bypass connections. These networks were under the control of a software defined network (SDN) controller. The controller knew the wavelength resources within the networks. Several algorithms were applied to these networks to evaluate the effect of a bypass network and to identify the desired characteristics (to find short length path and decrease the probability of spectrum fragmentation) of an algorithm suitable for a network with bypass connections. The results of applying the proposed algorithms in two networks proved that the bypass connections increased the blocking probability in small topology but did not affect the results in large topology. The results in a large-scale network with bypass network were almost the same as the results in a network without bypass connections. Thus, bypass connections are suitable for large-scale network.

  • Miri, Majid
    et al.
    Ashtari, Elmira
    KTH.
    The Applicability of a Newly Developed Revit Add-in for Architects and Urban Designers When Doing Daylight Study from Early Stages to the End of Architectural/Urban Design2019Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Including daylighting strategies from early to the end in the building and urban design process is crucial when it comes to the compliance of environmental certification systems or when the aim is to simply create an interior or exterior space with sufficient access to natural light while still thermally comfortable. Therefore, in this paper, we are going to introduce and discuss a new tool that is an add-in for Autodesk Revit and newly developed by the authors to help architects or urban designers/planners to evaluate daylight condition of exterior or interior spaces by calculating different daylight metrics in different design stages. Since, in a BIM model, most of the information that is needed for daylight analysis are already included in the model, lots of time and human errors can be reduced, if there is a possibility to make direct communication between the BIM model and Radiance that is a physically valid lighting and daylighting simulation software and works as the main calculation core for doing different types of daylight simulations in this add-in. Thus, by saving time and minimizing the mistakes and associated problems when exporting the model for analysis directly from Revit to Radiance and importing the results vice versa, this new add-in makes its users free from using any other third- party software. All in all, the main goal of this add-in is to work as a supportive decision-making tool for those dealing with indoor or outdoor quantity and quality of daylight and its associate threats during architectural design process. Moreover, its results can be used for other assessments such as when doing a thermal comfort analyses or electrical energy consumption in a building. Therefore, it can be helpful for architects, urban designers/planners, and engineers in their everyday works.

  • Waldau, Leonard
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Marina system.
    Development of an aquatic UAV capable of vertical takeoff from water2019Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    This report presents a master’s thesis edition involving the Maribot Petrel project, which concerns the development of a long range aquatic UAV capable of vertical takeoff from water in order to hop between different locations and to perform measurements in archipelago conditions. A concept evaluation phase was performed where multiple aquatic UAV ideas were investigated. This phase led to the conclusion that a flying wing with nose-tilting engine was the best concept to further invest in. Further, two prototypes of different sizes were then constructed and tested with positive results. The concept proved to be a promising platform for further development of the project.

  • Pavlovic, Boban
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Flygdynamik.
    Dynamic Performance Analysis of a Fighter Jet with Nonlinear Dynamic Inversion2019Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    A modern view of aircraft performance analysis, is to quantify aircraft manoeuvrability with agility metrics. There are several different agility metrics, which can be seen as indexing of the aircraft agility performance. The quantified unit is the time it takes for the aircraft to perform a specific manoeuvre relevant to a given agility metric. In this thesis, estimations are done of two agility metrics, the CCT (Combat Cycle Time) and the T90 (Time to capture 90◦ bank angle) for the F-18 HARV aircraft.Estimations of the agility metrics were obtained by simulating a six-degree-of-freedom aircraft model of the F-18 HARV aircraft performing the specific manoeuvres. To control the aircraft model during the simulation a control sys-tem was developed based on the NDI (Nonlinear Dynamic Inversion) method with time scale separation assumption. The method uses the feedback from the controlsystem for linearizing the aircraft system, which results in that simple linear controllers can be applied to the nonlinear aircraft model.In this case simple proportional controllers were implemented and in the case of estimating the T90 agility metric additional gain scheduling as functions of altitude and Mach number was required to extract maximum performance. Although the control system was developed for these two specific agility metrics, results indicates that the NDI method provides an effective way to implement controllers for complex systems, especially when considering a high nonlinear flight regime.

  • Ekman, Fanny
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Marina system.
    Operationalizing the SDGs in a Systems Engineering Framework for ship design concept studies2019Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Sustainable transport involves more choices and possibilities than ever before, and the topic is widely discussed within the maritime industry.

    To a large extent the innovations and technology exists, but even though there is a drive and consciousness to change, sustainability is still not a cornerstone in the decision-making process when new ships and transport solutions are developed. The gap between sustainability ambitions and actual actions is far from closed.

    This thesis introduces a new framework called Systems Engineering for Sustainable Ship design (SE4SS), which is based on the Systems Engineering methodology for conducting concept developments and the Sustainable Development Goals (SDG) for operationalizing sustainability.

    The new framework makes sustainability aspects an essential part of ship design concept development and the following decision-making process.

    The SE4SS framework includes an application of the SDGs on a product level (ship) and suggests appropriate tools & methods for sustainability assessment, considering different levels of ambitions and amount of available resources that projects may have.

    The framework has been validated against three cases of ship design concept development within the commissioner organization SSPA. The result shows that the suggested approach is useful in terms of ; (1) raising a holistic awareness of sustainability aspects in ship design, highlighting the existing opportunities and responsibilities, (2) creating a more transparent trade-off analysis where priorities need to be stated, preventing greenwashing, (3) structuring the process which facilitates the integration of sustainability aspects from the start and the communication between the project manager/naval architect and different stakeholders. Full-scale application of the SE4SS is needed in order to fully validate its usability and generalizability, however this thesis argues that the introduced framework may be a valuable tool in both illuminating and reducing the ambition-action gap within the maritime sector.

  • Díaz Vázquez, Guillermo
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Flygdynamik.
    Case Data Analysis Tool for PowerFLOW2019Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    The field of computational fluid dynamics (CFD) is exponentially growing in terms of performance, robustness, and applications. The expansion of CFD also means more users and more simulations, which translates into more human errors and mistakes in the simulation set up. Because the simulation set up should be the correct in order to accurately reproduce the desired phenomenon, such errors must be mitigated in order to increase the reliability and robustness of the simulations. In this project a tool has been developed to tackle this issue, within the CFD software SIMULIA PowerFLOW. The tool extracts and analyzes the data of the cases before simulation, reporting the results to the user for error detection. The present work aims to present the implementation, the application and the benefits of the designed tool.

  • Chea, Ming Kai
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Lättkonstruktioner.
    Investigating In-plane Shear Behaviour of Uncured Unidirectional Prepreg Tapes2019Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Steering of prepreg tows in an automated fibre placement (AFP) process allows geodesic layup trajectory over a doubly-curved surface, as well as the potential to improve the efficiency of composite structures by tailoring their stiffness. However, defects (such as out-of-plane buckling and tow pull off) are commonly generated when the steering radius exceeds a critical limit, which impact the mechanical properties of the finished product.

    The in- and out-of-plane material properties of the prepreg tows have been shown to significantly influence the quality of the layup. In this thesis, in-plane shear behaviour of uncured IMA-M21 unidirectional (UD) prepreg was characterised using an off-axis tensile test to derive material parameters for process models to predict steering limits and defects.

    Test parameters, such as shear strain rates and temperatures, that were investigated were consistent to the actual AFP process. The results demonstrates the expected strain-rate and temperature dependencies related to the resins viscoelastic behaviour. Subsequently, a novel micro-mechanical finite element (FE) simulation of a 3-dimensional UD prepreg unit cell in pure shear was conducted to gain qualitative insights into the complex rheological behaviour at play. It effectively demonstrates how fibre friction, resin viscosity and shear strain rates influence the load transfer between fibres and melt, as well as the movement of fibres during the shearing process. These were reflected in the shear stress-strain curves generated in the simulation and elastic micro-buckling observed in the fibre elements. The results pave a way for future development of a robust material model for predicting the critical process parameters to achieve quality layups from AFP steering process.

  • Källgren, Tom
    et al.
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik.
    Nordling, Olof
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik.
    Community Supported Agriculture” i Sverige: Modellens bidrag till ett hållbart livsmedelssystem2019Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [sv]

    Runtom i världen finns många modeller, mål och visioner för en hållbar utveckling, och många av dessa kan kopplas till jordbruk. Livsmedelsproduktion är en av de viktigaste industrierna vi har och är även källan till en stor del av utsläpp, färskvattenanvändning, övergödning och annan problematik kring miljö, ekonomi, levnadsvillkor och mycket mer. För att säkra en hållbar utveckling för samhället i stort är alltså produktionen av mat en viktig pusselbit, men utvecklingen de senaste hundra åren har gått mot en intensifiering, globalisering och mekanisering av jordbruket utan dess like.

    Som en motreaktion på detta har flera alternativa livsmedelssystem utvecklats med olika skalor, utgångspunkter och resultat. Ett av dessa system är konceptet Community Supported Agriculture (CSA), eller andelsjordbruk som det kallas på svenska. Konceptet utvecklades redan på 60-talet i Europa och Japan och kom till USA på 80-talet där det sedan dess har expanderat enormt, men i Sverige är det fortfarande relativt nytt och kunskapen kring andelsjordbruk är liten. De flesta av det 50-tal CSA-gårdar som finns i landet har tillkommit de senaste åren och för konsumenter, lagstiftare och jordbrukare finns ännu inte det forskningsunderlag som krävs för att fatta beslut kring och släppa fram utvecklingen av konceptet.

    Detta arbete ämnar att lyfta fram de sätt som CSA-modellen kan bidra till en hållbar utveckling. Detta genom att genomföra en litteraturstudie om modellen och hållbara livsmedelssystem i allmänhet och sedan koppla resultaten till de uppsatta målen för hållbar utveckling som finns på global, nationell och lokal nivå. Från resultaten görs även jämförelser med en fallstudie-referens, CSA-gården Under Tallarna i Södertälje. Resultaten indikerar att CSA har mycket att bidra med i flera aspekter av hållbar utveckling. Utöver hållbar produktion av livsmedel finns det nyttor bland annat inom hälsa, ekonomi, utveckling av landsbygd, lokalsamhällen och kultur. För att uppnå de satta hållbarhetsmålen krävs en omställning av livsmedelssystemet och det konventionella jordbruket i dess kärna. Resultatet av studien visar att CSA-konceptet, med stöd från intressenter i och kring livsmedelssystemet, har potential att möjliggöra en sådan omställning.

  • Tegbrant, Kerstin
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH).
    Cost-effectiveness of ergonomic interventions - Evaluation of a calculation model2019Independent thesis Advanced level (degree of Master (One Year)), 10 poäng / 15 hpOppgave
    Abstract [en]

    Several studies have shown that the work environment affects company performance. The managers are seldom aware to which extent work environment problems affect productivity, quality of delivery and sick-leave in their organisation. The present literature study showed that improvements regarding physical ergonomics generally are shown to be cost-effective. The most beneficial way of working is through proactive measures interactively with employees. An efficient, systematic way of performing risk assessments and interventions reduce the need for a calculation method. This study identified propositions for properties of calculation methods. These propositions were : “Simplicity, high usability”, “Right content for the target group”, “High ability to measure risk”, “Focus on staff”, “Correct standardised values”, “Right focus” and “Optimal design”. Scania CV, a producer of trucks and buses, has developed a calculation model for cost-effectiveness of ergonomic interventions. Evaluation of this model with semi-structured interviews showed agreement regarding the need of a simplified calculation method, based on systematic risk assessments.

  • Zec, Kenan
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Medicinteknik och hälsosystem.
    Hansson, Sofia
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Medicinteknik och hälsosystem.
    Home Care Logistics: A Monitoring System with a Communication Unit for the Elderly2019Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [en]

    Humans are growing older which presents challenges for the health care system. One solution for allowing individuals to continue living in their home, despite age related dif- ficulties, is a sensor based surveillance system. These systems can monitor a number of parameters, for example motion or temperature. If certain limits are exceeded the sys- tem can notify family members or health care services. The aim of this project was to build a prototype of such a system which also had to be cheap and easy to install and maintain. The final prototype consists of a motion detection sensor in the bathroom, a temperature sensor around the kitchen stove and a temperature sensor for measurement of ambient room temperature. Each sensor is connected to its own Arduino and they are all programmed with different limits. The sensors communicate wirelessly with a central hub through the communication protocol LoRa. Once the central hub, which consists of a Raspberry Pi, receives a LoRa signal it sends an email to a chosen address.

  • Storfeldt, Joakim
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Flygdynamik.
    Design benefits with Additive Manufacturingfrom a convective heat transfer perspective2019Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Nowadays manufacturing processes are rapidly developing. Salt-bath dip brazing is a conventional manufacturing method commonly used by Saab AB to fuse aluminium components in a high temperature salt bath. However conventional manufacturing methods have shown some limitations. Additive Manufacturing, or 3D printing, is a newer technology which has become very popular in the industry offering competitive advantages regarding production time and size, and structural complexity of the components among other aspects. In this work, Additive Manufacturing is investigated to assess if the performance of heat sinks can be increased compared to the salt-bath dip brazing method.

    Geometrical shapes of heat sink-fins were studied by empirical research to compare their characteristics in air-flow, convection and pressure drop. Eight different geometrical shapes have been analyzed using Additive Manufacturing, and the control plate fins was used as a reference for comparison with salt-bath dip brazing. It was found out that the NACA 0010 fins and Square Grid fins geometries gave the best performance with a 63% and 64% decrease in pressure drop per diverted energy compared to the control plate fins, respectively.

  • Disputas: 2019-11-06 10:00 Kollegiesalen, Stockholm
    Song, Meng
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elkraftteknik.
    Planning and Operation of Demand-Side Flexibility2019Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Power systems are changing with growing penetration of non-dispatchable renewable generation and increased demand of electric energy. More generation, transmission or distribution capacities are needed to balance the varying production and higher consumption. Demand-side flexibility is a potential solutionto tackle those challenges. By shifting the consumption time and temporarily increase or decrease the power demand, the demand-side flexibility can help to integrate more wind and solar energy in the system, alleviate network congestion and postpone the investment for grid reinforcement. Therefore, technical and regulatory measures are undergoing in many countries to encourage demand response and engage customers.

    On the other hand, unlocking the flexibility will introduce more complexityand uncertainty on demand side. This would result in difficulties for different actors in power systems and power markets to make optimal decisionsin their planning and operation. The thesis addresses the problem by proposing methods to support the decision making of actors on demand side. Firstly, it develops models to facilitate residential customers and commercial electric vehicle fleet operators scheduling their shiftable appliances for reducing electricity cost. The willingness of households for responding to time-varying price is taken into account. Results from Stockholm Royal Seaport project are analysed to demonstrate such willingness. Secondly, the thesis develops models for the short-term planning of retailers and balance responsible players. Different approaches are deployed under price-taker and price-maker assumptions respectively. The planning concerns the price sensitivityof end customers and the risk related with certain bidding strategies.Thirdly, the thesis proposes models to coordinate and aggregate the flexible charging power of electric vehicles to provide regulation service on the balancing market. The models encompass the decision process from day-aheadplanning to real-time operation management. The proposed models in the thesis are based on the rules of Nordic electricity market and could be further developed for adapting to other market frameworks. Stochastic programmingis applied to address the uncertainties about consumption and market behaviours.In addition, the thesis discusses the impacts of demand response interms of generation cost, system reliability and market price. It shows that a widely implemented demand response can reduce the total generation cost, improve the reliability of supply and decrease the market price.

  • Disputas: 2019-12-03 10:00 Kollegiesalen, Stockholm
    Ahmed, Laeeq
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Beräkningsvetenskap och beräkningsteknik (CST).
    Scalable Analysis of Large Datasets in Life Sciences2019Doktoravhandling, monografi (Annet vitenskapelig)
    Abstract [en]

    We are experiencing a deluge of data in all fields of scientific and business research, particularly in the life sciences, due to the development of better instrumentation and the rapid advancements that have occurred in information technology in recent times. There are major challenges when it comes to handling such large amounts of data. These range from the practicalities of managing these large volumes of data, to understanding the meaning and practical implications of the data.

    In this thesis, I present parallel methods to efficiently manage, process, analyse and visualize large sets of data from several life sciences fields at a rapid rate, while building and utilizing various machine learning techniques in a novel way. Most of the work is centred on applying the latest Big Data Analytics frameworks for creating efficient virtual screening strategies while working with large datasets. Virtual screening is a method in cheminformatics used for Drug discovery by searching large libraries of molecule structures. I also present a method for the analysis of large Electroencephalography data in real time. Electroencephalography is one of the main techniques used to measure the brain electrical activity.

    First, I evaluate the suitability of Spark, a parallel framework for large datasets, for performing parallel ligand-based virtual screening. As a case study, I classify molecular library using prebuilt classification models to filter out the active molecules. I also demonstrate a strategy to create cloud-ready pipelines for structure-based virtual screening. The major advantages of this strategy are increased productivity and high throughput. In this work, I show that Spark can be applied to virtual screening, and that it is, in general, an appropriate solution for large-scale parallel pipelining. Moreover, I illustrate how Big Data analytics are valuable in working with life sciences datasets.

    Secondly, I present a method to further reduce the overall time of the structured-based virtual screening strategy using machine learning and a conformal-prediction-based iterative modelling strategy. The idea is to only dock those molecules that have a better than average chance of being an inhibitor when searching for molecules that could potentially be used as drugs. Using machine learning models from this work, I built a web service to predict the target profile of multiple compounds against ready-made models for a list of targets where 3D structures are available. These target predictions can be used to understand off-target effects, for example in the early stages of drug discovery projects.

    Thirdly, I present a method to detect seizures in long term Electroencephalography readings - this method works in real time taking the ongoing readings in as live data streams. The method involves tackling the challenges of real-time decision-making, storing large datasets in memory and updating the prediction model with newly produced data at a rapid rate. The resulting algorithm not only classifies seizures in real time, it also learns the threshold in real time. I also present a new feature "top-k amplitude measure" for classifying which parts of the data correspond to seizures. Furthermore, this feature helps to reduce the amount of data that needs to be processed in the subsequent steps.

  • Putra, Ramadhani Pamapta
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH).
    Implementation and Evaluation of WebAssembly Modules on Embedded System-based Basic Biomedical Sensors2019Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    WebAssembly is a new binary code specification, which was initially designed to complement JavaScript in web applications. WebAssembly is inherently portable and small, designed for multiplatform usage. Therefore, WebAssembly modules can be created to support embedded system-based biomedical sensor operation. However, WebAssembly has its own limitations to compensate with its portability. In this thesis, we show how WebAssembly modules can be applied to the basic biomedical modalities of body temperature, heart rate, and breathing pattern.  We show how the implementation performed, and what challenges were met during the development. It is concluded that WebAssembly can be applied for achieving safe and effective biomedical sensor devices, although with some limitations.

  • Rahgozar, Parastu
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH).
    Evaluation of a Radiomics Model for Classification of Lung Nodules2019Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Lung cancer has been a major cause of death among types of cancers in the world. In the early stages, lung nodules can be detected by the aid of imaging modalities such as Computed Tomography (CT). In this stage, radiologists look for irregular rounded-shaped nodules in the lung which are normally less than 3 centimeters in diameter. Recent advancements in image analysis have proven that images contain more information than regular parameters such as intensity, histogram and morphological details. Therefore, in this project we have focused on extracting quantitative, hand-crafted features from nearly 1400 lung CT images to train a variety of classifiers based on them. In the first experiment, in total 424 Radiomics features per image has been used to train classifiers such as: Random Forest (RF), Support Vector Machine (SVM), Decision Tree (DT), Naive Bayes (NB), Linear Discriminant Analysis (LDA) and Multi-Layer Perceptron (MLP). In the second experiment, we evaluate each feature category separately with our classifiers. The third experiment includes wrapper feature selection methods (Forward/Backward/Recursive) and filter-based feature selection methods (Fisher score, Gini Index and Mutual information). They have been implemented to find the most relevant feature set in model construction. Performance of each learning method has been evaluated by accuracy score, wherewe achieved the highest accuracy of 78% with Random Forest classifier (74% in 5-fold average) and 0.82 Area Under the Receiver Operating Characteristics (AUROC) curve. After RF, NB and MLP showed the best average accuracy of 71.4% and 71% respectively.

  • Nicolle, Mathias
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Rymdteknik.
    Mechanical and structural conceptof the ISS microgravity experimentpayload: AtmoFlow2019Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    This Master Thesis report presents the mechanical concept and design of a microgravity fluid science experiment that is planned to be launched to the International Space Station in approximately five years. Named AtmoFlow, this experiment aims to study the complex flow phenomena occurring in different planets’ atmosphere by implementing a scaled-down model of a planet-atmosphere system in microgravity. The design introduced here focuses on several of the experiment’s systems: the Turn Table, a rotating system involving a Fluid Cell Assembly, a Thermal Control System and two Rotation Drive Systems. Design methods, main choices and crucial conception steps are presented. Components’ dimensioning and choices are motivated. Models and analyses are derived from the selected design to ensure that the design meets the requirements on microgravity disturbances, structural and rotational characteristics stated during previous project’s phases. The Computer Assisted Design model of the experiment’s final concept and its integration sequence are eventually proposed and discussed.

  • Wanner, Svenja
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Lättkonstruktioner.
    Systematic approach on conducting fatigue testing of unidirectional continuous carbon fibre composites2019Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    High fuel saving potentials, increased load carrying capacities and therefore competitive advantages force the heavy goods vehicle industry to enhance the efforts towards comprehensive lightweight designs. Facing this challenge, the material evaluation in terms of simulations and physical testing of composite materials is required for the design against fatigue failure due to road introduced vibrations. Eliminating fatigue testing issues in order to gain acceptable and reproducible results, a future-oriented systematic approach on conducting constant amplitude tension-tension fatigue testing on a unidirectional composite material is presented. Following the material characterisation of the carbon/epoxy material in terms of tensile and shear properties as well as fibre volume fraction, several combinations of tab configurations and specimen geometries have been tested with regard to their suitability for fatigue testing. Finally, the unidirectional material was successfully tested under tension-tension fatigue and first elaborated test data were assessed. In conclusion, the usage of straight aluminium tabs completely clamped inside the grips and bonded to the straight-sided specimen with 3M DP420 adhesive, using ventilation during the test is the recommended test procedure.

  • Shwan Kurdi, Mir
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Flygdynamik.
    Nonlinear Attitude Control ofa Generic Aircraft2019Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Determining suitable controllers for the process of evaluating dynamic per-formance of multiple versions of an aircraft’s aerodynamical, geometric and propulsive properties in its conceptual stage is an expensive task.In this report a proposition is made to utilize a generalized feedback lin-earizing controller that o˙ers the aircraft designer valuable insight into the manoeuvre performance of their aircraft. This is carried out by first estab-lishing fundamental requirements for a controller capable of treating a generic airframe, and formulating the resulting control laws.It is shown in this report, that with a suÿciently simple aerodynamic and propulsive model explicit feedback linearization is possible with satisfactory performance and robustness. Whereas it would be necessary to implement INDI if explicit inverse mappings are not obtainable. Which in turn would introduce additional tuning parameters.Robustness verification is performed in two stages, firstly by introducing a high model uncertainty within the flight control system and showing, via simulation, that the control system successfully performs desired multi-axial manoeuvres whilst managing to maintain the induced side slip below 0.1◦. Secondly by disturbing the aircraft with a discrete side slip. Critical side slip disturbance angle was found to be considerably larger than that for regular aircraft entailing that the used case study may be somewhat over dimensioned with respect to yaw control authority.

  • Philippe, Alexis
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Flygdynamik.
    Optimisation of an aeronautic production line through the managementof tools and the shortage of items2019Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    This thesis work is part of a process to ensure the production ramp-up of the A320neo aircraft pylons at Airbus Saint-Eloi factory (Toulouse). The aim of the project was to optimise the production management in order to sustain the transition to a serial production of the assembly lines. The objective of the thesis work was to develop a model to prevent the downtime of the production lines caused by the shortage of the assembly lines or the unavailability of tools on workstations.Firstly, the work investigates the existing models in order to understand the causes of stocks variability. Performance of tools was determined with the Markov chain model. Then, the work provides a method to forecast production needs in terms of items and tools. An algorithm was developed to collect and process the data on the existing resources in order to compare it to the forecasted needs. Solutions were designed to identify the causes of the shortages on the production lines. In addition, by analysing the trends of the shortage of stocks and the availability of tools on workstation, a forecast of long term constraints for production is possible. The method showed promising results to identify and manage the missing items and tooling on the workstations.

  • Lejon, Alexander
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Flygdynamik.
    Creation and Validation of Early Stage Conceptual Design Methodology for Blended WingBody Aircraft2019Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    The current design paradigm for developing tube-and-wing style aircraft has been well documented in literature. This research attempts to develop and val-idate a similar design methodology to what is presently utilized for tube-and-wing based aircraft, but has so far not been successfully implemented for the blended wing-body. This construction has no clear distinction between the lift generating surfaces and the cargo carrying structure. The methodology that was developed included the concatenation and validation of low-fidelity, low speed and low complexity aerodynamic models in order to allow for quick and simple analysis of a large number of possible geometries. This enables the user eÿciently determine the most promising candidate geometries for further study and/or development. Known issues with the low velocity and low com-plexity aerodynamic models include the absence of shock wave modelling, an important part in determining the aerodynamic performance of a lift generat-ing surface. The result of this work is the creation and documentation of a procedure for early-stage design of a blended wing-body airframe. However, due to convergence issues with the high-fidelity CFD solver, the methodology could not been validated for transonic flow. It can thus be only considered valid for flow velocities for which the Prandtl-Glauert correction is valid.

  • Lagemann, Benjamin
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Marina system.
    Efficient seakeeping performance predictions with CFD2019Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    With steadily increasing computational power, computational fluid dynamics (CFD) can be applied to unsteady problems such as seakeeping simulations. Therefore, a good balance between accuracy and computational speed is required. This thesis investigates the application of CFD to seakeeping performance predictions and aims to propose a best-practice procedure for efficient seakeeping simulations.

    The widely used KVLCC2 research vessel serves as a test case for this thesis and FINEŠ/Marine software package is used for CFD computations. In order to validate the simulations, results are compared to recent experimental data from SSPA as well as predictions with potential ˛ow code SHIPFLOW® Motions.

    As for the calm water simulations, both inviscid and viscous ˛ow computations are performed in combination with three mesh refinement levels.

    Seakeeping simulations with regular head waves of different wavelengths are set-up correspondingly. Furthermore, different strategies for time discretization are investigated. With the given computational resources, it is not feasible to complete seakeeping simulations with a ˝ne mesh. However, already the coarse meshes give good agreement to experiments and SHIPFLOW® Motions' predictions. Viscous ˛ow simulations turn out to be more robust than Euler ˛ow computations and thus should be preferred. Regarding the time discretization, a fixed time discretization of 150 steps per wave period has shown the best balance between accuracy and speed. Based on these findings, a best-practice procedure for seakeeping performance predictions in FINEŠ/Marine is established.

    Taking the most efficient settings obtained from head wave simulations, the vessel is subjected to oblique waves with 160° encounter angle. Under similar wave conditions, CFD predictions of a similar thesis show close agreement in terms of added wave resistance. Compared to the previous head wave conditions of this study, added resistance in 160° oblique waves is found to be significantly higher. This underlines that oblique bow quartering waves represent a relevant case for determining the maximum required power of a ship.

    CFD and potential ˛ow show similar accuracy with respect to ship motions and added wave resistance, albeit potential ˛ow outperforms CFD in terms of computational speed. Hence, CFD should be applied in cases where viscous effects are known to have large influence on a vessel's seakeeping behavior. This can be the case if motion control and damping devices are to be evaluated, for instance.

  • Kjelldorff, Maria
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Marina system.
    Water Current Measurements using Oceanographic Bottom LanderLoTUS?2019Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    oTUS is a Long Term Underwater Sensing, bottom landing, node for observations of ocean water temperatures. LoTUS measures temperature (moored to the seafloor) according to a spec-ified time schedule until, at the end of the mission, it surfaces to transmit the collected data to on shore recipients using an Iridium link. The paper presents an extension of the sensing capability to include water current velocity (speed and direction) using a robust, reliable and inexpensive Eulerian method. The method is based on the "tilting stick" principle where a combination of inertia measurement data and magnetic sensor data is used. The paper discusses the principal technique, the modeling of the system, practical considerations, and optimization of the setup for specific flow conditions along with verifying experimental data.

  • Janson, Rebecca
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, MWL Marcus Wallenberg Laboratoriet.
    A simplified model for the design of floor structures with vibrating sources for architectural applications2019Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    When designing a building, sound is one of the problems to take into account. Vibrating machines, such as ventilation fans, water pumps and compressors, generate structure-borne sound. The structure-borne sound travels up the structure of the building and generates sound in adjacent rooms. To be able to predict the sound radiated in the adjacent rooms when designing a building, a semi-analytical model has been developed. Using the incident vibrations from the floor plate where the vibrating machine is standing, the transmission loss in the junction between the floor plates and the wall plate is calculated. This can bed one in every junction in the building, creating a system of multiple junctions. The sound radiation to the adjacent rooms is later approximated using the velocity of the plates.The model is verified with measurements in two case studies. This shows that the model has good potential in predicting the normal acceleration amplitudes in the relevant plates. The two case studies have different geometric properties and different sources. The comparison between the model and the measurement gives similar results. The model analyses the output of the bending waves since this is the wave type that radiates sound, but longitudinal waves are present in the model. With only two case studies it is too early to say that the model works for all systems, but it could be used as a fist approach. The model, right now, is restricted to isotropic, homogeneous material without losses. A parametric study shows that the transmission loss is dependent on the ratio between the thicknesses of the floor plate and the wall plate. The ratio should be as large as possible to get a high transmission loss, but depends on how the junction is structured.