Global ETD Search

1	Evaluating intrusion detection points in an end-to-end solution Pankaczi, Lilla January 2023 (has links) Evaluating all intrusion detection points in an end-to-end cyber-physical system can be challenging. This master thesis focuses on evaluating the security of the most exposed part of such systems, Radio Frequency Identification (RFID) communication. As both the RFID reader and tag can be located outside of secure premises, RFID communication can be a target of several cyber threats. Common cyber-attacks such as replay attacks, eavesdropping, or tag cloning can be associated with the lack of security of the communication channel between the reader and the tag or flaws of the implemented authentication protocols and encryption algorithms. This thesis briefly summarizes parts 4 and 3 of the ISO/IEC 14443 standard, which specify the initialization, selection, and transmission protocols in high-frequency RFID smart-card and reader communication. A formal security analysis was conducted to evaluate these protocols using a tool called Scyther. Then, an improved authentication protocol was proposed utilizing a commercially available feature, the Random Unique Identifier of the card (RID). The Scyther protocol verification results showed that implementing RID can prevent many RFID attacks such as, eavesdropping or replay attacks, and protect the cardholder's privacy. RFID Random UID Mutual Authentication Scyther Computer Engineering Datorteknik
2	A Conformal Mapping Grid Generation Method for Modeling High-Fidelity Aeroelastic Simulations Worley, Gregory 2010 May 1900 (has links) This work presents a method for building a three-dimensional mesh from two- dimensional topologically identical layers, for use in aeroelastic simulations. The method allows modeling of large deformations of the wing in both the span direction and deformations in the cord of the wing. In addition, the method allows for the modeling of wings attached to fuselages. The mesh created is a hybrid mesh, which allows cell clustering in the viscous region. The generated mesh is high quality and allows capturing of nonlinear uid structure interactions in the form of limit cycle oscillation. Aeroelasticity unsteady aerodynamics computational fl uid dynamics grid generation conformal mapping limit cycle oscillation nonlinear
3	Automatisk taligenkänning som metod för att undersöka artikulationshastighet i svenska / Automatic speech recognition as a method to investigate articulation rate in Swedish Martin Björkdahl, Liv January 2022 (has links) Den senaste tidens utveckling inom automatisk taligenkänning har lett till mindre resurskrävan-de och mer effektiva modeller. Detta innebär nya möjligheter för forskning kring spontant tal.I den här studien används Kungliga Bibliotekets svenska version av Wav2Vec 2.0 och en tal-korpus skapas utifrån ljudklipp från Sveriges Radio för att undersöka artikulationshastighet ispontant tal. Artikulationshastighet har setts ha en negativ korrelation till informationsdensiteti tidigare studier. Utifrån Uniform Information Density-hypotesens antagande; att talare strävarefter att jämna ut distributionen av information i ett yttrande, undersöks om de sammanlagdadependenslängderna mellan alla huvud och dependenter i meningar är korrelerat med artiku-lationshastigheten. Studien visar att metoden där artikulationshastighet beräknas med hjälp avKB:s Wav2Vec 2.0 leder till systematiskt högre artikulationshastighet än vid en manuell beräk-ning. Samt att korrelationen mellan antal stavelser i ett ord och artikulationshastighet blir denomvända mot vad tidigare studier med manuella metoder visat. Hypotesen att längre depen-denslängd skulle vara relaterat till högre artikulationshastighet får inget stöd i studien. Iställetses en motsatt effekt av minskande artikulationshastighet i relation till ökande dependenslängd.Studien belyser behovet av en modell specialiserad för beräkning av duration för att vidare ut-forska artikulationshastighet genom automatisk taligenkänning. / The last few years progress within automatic speech recognition has led to models that are lessresource demanding and more effective. This means new possibilities in the research regardingspontaneous speech. In this study, KB:s Swedish version of Wav2Vec 2.0 is used to create aspeech corpus and investigate articulation rate in spontaneous speech, with data from SverigesRadio. This study aims to investigate if this is a good method. It has been observed in previousstudies that articulation rate is negatively correlated to information density. With the uniforminformation density hypothesis; that speakers aim to distribute information evenly in an utteran-ce, as a base - this study aims to investigate whether the sum of the word dependency lengths insentences is correlated to articulation rate. The result shows that the method of calculating ar-ticulation rate with KB:s Wav2Vec 2.0 leads to systematically higher articulation rates comparedto results of a manual method. The hypothesis that longer dependency lengths would correlatewith higher articulation rates is not supported in the results. Instead the opposite effect can be observed. The study shows the need for a model specialized in calculating duration for futureresearch regarding articulation rate with automatic speech recognition.KeywordsASR, automatic speech recognition, UID, articulation rate, dependency length, dependecy mi-nimization, corpus studies, information density ASR automatic speech recognition articulation rate UID dependency length dependency minimization information density ASR taligenkänning artikulationshastighet Wav2Vec 2.0 dependenslängd korpusstudier informationsdensitet UID dependenslängdsminimering General Language Studies and Linguistics
4	Motion Analysis of Fluid Flow in a Spinning Disk Reactor Korzhova, Valentina N. 18 September 2009 (has links) The ow of a liquid _lm over a rapidly rotating horizontal disk has numerous industrial applications including pharmaceuticals, chemical engineering, bioengineering, etc. The analysis and control of complex uid ows over a rapidly rotating horizontal disk is an important issue in the experimental uid mechanics. The spinning disk reactor exploits the bene_ts of centrifugal force, which produces thin highly sheared _lms due to radial acceleration. The hydrodynamics of the _lm results in excellent uid mixing and high heat or mass transfer rates. This work focuses on developing a novel approach for uid ow tracking and analysis. Speci_cally, the developed algorithm is able to detect the moving waves and compute controlling _lm ow parameters for the uid owing over a rotating disk. The input to this algorithm is an easily acquired non-invasive video data. It is shown that under single light illumination it is possible to track specular portion of the reected light on the moving wave. Hence, the uid wave motion can be tracked and uid ow parameters can be computed. The uid ow parameters include wave velocities, wave inclination angles, and distances between consecutive waves. Once the parameters are computed, their accuracy is analyzed and compared with the solutions of the mathematical uid dynamics models based on the Navier-Stokes equations for the case of a thin _lm. The uid model predicts wave characteristics based on directly measured controlling parameters, such as disk rotation speed and uid ow rate. It is shown that the calculated parameter values approximately coincide with the predicted ones. The average computed parameters were within 5 � 10% of the predicted values. In addition, given recovered uid characteristics and uid ow controlling parameters, full 3D wave description is obtained. That includes 3D wave location, speed, and distance between waves, as well as approximate wave thickness. Next, the developed approach is generalized to model-based recovery of uid ow controlling parameters: the speed of the spinning disk and the initial uid-ow rate. The search in space for model parameters is performed as to minimize the error between the ow characteristics predicted by the uid dynamics model (e.g. distance between waves, wave inclination angles) and parameters recovered from video data. Results demonstrate that the speed of a disk and the ow rate are recovered with high accuracy. When compared to the ground truth available from direct observation, we noted that the controlling parameters were estimated with less than 10% error. image processing uid- ow tracking wave detection wave velocity wave inclination mathematical modeling American Studies Arts and Humanities Computer Engineering Computer Sciences
5	SPAN (Special Protection Area Network) : A platform to protect bird protection areas Kreiser, Kilian January 2013 (has links) Background The foundation for life on our planet are all the resources we can draw upon: sunlight, clean water, fresh air and many more. But one existential resource a lot of people are not aware of, is the rich variety of life forms on earth. Biodiversity surrounds us every day: It is in the clothes we wear, the food we eat and the medicine we take. It is also an important driver for tourism, economy and technology: Various technological innovations are directly inspired by nature.But biodiversity is degrading rapidly caused by the rising land consumption in many countries. In Germany, this pressure is exceedingly high: 70% of natural habitats are endangered, 40% of animal species are on the IUCN red list and every second bird species is threatened.Using scientific methods and inventive technology, SPAN helps to monitor bird protection areas in Germany and to collect data as a basis to enforce conservation supported by European legislation. / Methods Involving all important stakeholders was inevitable to make sure the result will fit their needs. In meetings with coordinators of different existing caretaker networks in Berlin I learned about the organizational aspects and got an holistic perspective on the topic. The creation of blueprint drafts and stakeholder maps in an early phase was an effective way to figure out what kind of touchpoints are needed by which users.Voluntary caretakers who monitor protection areas are the primary users, so I conducted interviews with caretakers of other networks to learn everything about their monitoring work, their needs and experiences.An in-depth analysis and synthesis of my research findings led to the ideation phase where I explored in which ways I could involve, educate, bond and assist caretakers with diverse profiles. Getting their feedback on the ideas helped me to select the most promising concepts and consolidate the final result. / Result SPAN consists of a web-application and a smartphone app performing a wide range of functions for caretakers of protection areas. With their help they can retrieve information, network with other caretakers, conduct monitoring activities and submit reports about the condition of protection areas.With SPAN, caretakers can learn about habitats, species, and other caretakers who help with monitoring them. Together they can plan their activities and exchange information with the shared schedule and annotation tools.With the smartphone app, caretakers can take notes or retrieve location based information while being out in the field. Another mobile feature are customizable print-out forms making the caretakers independent from access to power or signal-coverage.Filled-in forms are digitalized and put into the database with the help of an image recognition scanning tool.With SPAN, caretakers can also lend unmanned photogrammetry vehicles to conduct aerial monitoring in a feasible and easy-to-use way. / SPAN - A platform to monitor bird protection areas. UID Umeå Institute of Design Interaction Design Biodiversity Biodiversity Protection Natura 2000 Nature Conservation Design and Nature Protection Design Design Human Computer Interaction
6	Investigation of performance and surge behavior of centrifugal compressors through CFD simulations Tosto, Francesco January 2018 (has links) The use of turbocharged Diesel engines is nowadays a widespread practice in the automotive sector: heavy-duty vehicles like trucks or buses, in particular, are often equipped with turbocharged engines. An accurate study of the flow field developing inside both the main components of a turbocharger, i.e. compressor and turbine, is therefore necessary: the synergistic use of CFD simulations and experimental tests allows to fulfill this requirement. The aim of this thesis is to investigate the performance and the flow field that develops inside a centrifugal compressor for automotive turbochargers. The study is carried out by means of numerical simulations, both steady-state and transient, based on RANS models (Reynolds Averaged Navier-Stokes equations). The code utilized for the numerical simulations is Ansys CFX. The first part of the work is an engineering attempt to develop a CFD method for predicting the performance of a centrifugal compressor which is based solely on steady-state RANS models. The results obtained are then compared with experimental observations. The study continues with an analysis of the sensitivity of the developed CFD method to different parameters: influence of both position and model used for the rotor-stator interfaces and the axial tip-clearance on the global performances is studied and quantified. In the second part, a design optimization study based on the Design of Experiments (DoE) approach is performed. In detail, transient RANS simulations are used to identify which geometry of the recirculation cavity hollowed inside the compressor shroud (ported shroud design) allows to mitigate the backflow that appears at low mass-flow rates. Backflow can be observed when the operational point of the compressor is suddenly moved from design to surge conditions. On actual heavy-duty vehicles, these conditions may arise when a rapid gear shift is performed. / Användningen av turboladdade dieselmotorer ärr numera utbredd inom bilindustrin: i synnerhet tunga fordon som lastbilar eller bussar ärr ofta utrustade med turbo-laddade motorer. En utförlig förståelse av ﬂödesfältet som utvecklas innuti båda huvudkomponenterna hos en turboladdare, dvs kompressor och turbin, är därför nödvändig: den synergistiska användningen av CFD-simuleringar och experimentel-la tester möjliggör att detta krav uppfylls. Syftet med denna avhandling är att undersöka prestanda och det ﬂödesfält som utvecklas i en centrifugalkompressor för turboladdare. Studien utförs genom nu-meriska simuleringar, både steady state och transient, baserat på RANS-modeller (Reynolds Averaged Navier-Stokes-ekvationer). Koden som används för de numeriska simuleringarna är Ansys CFX. Den första delen av arbetet ¨ar ett försöka att utveckla en CFD-metod för att förutsäga prestanda för en centrifugalkompressor med hjälp av steady-state RANS-modeller. De erhållna resultaten jämförs sedan med experimentella observationer. Studien fortsätter med en analys av känsligheten hos den utvecklade CFD-metoden till olika parametrar: Inﬂytande av både position och modell som används för rotor-statorgränssnitt samt axiellt spel mellan rotor och hus på de globala prestationerna studeras och kvantiﬁeras. I andra delen utförs en designoptimeringsstudie baserad på Design of Experiments (DoE). I detalj används tidsupplösta RANS-simuleringar för att identiﬁera vilken utformning av ported shroud som minskar backﬂöde i kompressorn under en snabb minskning av massﬂöde och varvtal och därmed ger bättre prestanda i transient surge. På tunga fordon kan dessa förhållanden uppstå under växling. centrifugal compressor Computational Fluid Dynamics (CFD) RANS surge compressible uid dynamics Design of Experiments (DoE). centrifugalkompressor CFD-simulering RANS overskott komprimerbar vatskedynamik Design of Experiments (DoE) Engineering and Technology Teknik och teknologier
7	Carrie : Handla miljövänligare / Carrie : Greener grocery shopping Lenkeit Gesser, Malin January 2019 (has links) Ett av de mest hotande problemen idag är vad som händer med miljö. Ett stort problem är utsläpp. En stor bidragande faktor är den tanklösa användningen av fordon drivna av fossila bränslen. Ett sätt att kunna ta ett litet steg i rätt riktning, är att anpassa våran livstil och till exempel minska på användningen av bilen. Men även att allmänt göra mer medvetna val i vardagen. Målet med detta projektet är att göra just detta lite enklare. Att hjälpa dig transportera dina matvaror exempelvis från mataffären till hemmet.Processen för att komma fram till det som blev slutprodukten, började med intervjuer av användare. Därefter producerades skisser som visades för en testgrupp, för att samla feedback. Fysiska tester utfördes, innan det slutgiltiga konceptet nåtts: En vagn man kan använda på fyra sätt. Man kan skjuta den framför sig medan man går, eller dra den efter sig, man kan använda den som sparkcykel eller man kan koppla den till en cykel. / One of the most threatening issues today is what is happening to our environment. A consi- derable problem for these issues are the emissions. A tremendous contributing factor is the insensible use of fossil fuel driven vehicles. A way of taking a small step i the right direction is to adjust our lifestyle and reduce the use of the car. But also by making more conscious choises in our everyday lives. The aim of this project is to make this a little easier. To help you transport your groceries from for example the store to your home.The process of coming up with what later became the end product, started with interviewing users. Following that, sketches were made and showed to a test group to gather feedback.Physical tests executed, before the final concept was reached: A wagon you cam utilise infour ways. It can be pushed in front of you, while walking. It can be dragged behind, while walking. it can be used as a kick bike and it can be connected to a bicycle. Greceries shopping grocdery shopping green greener fossil free environment environment friendly transport transporting Carrie carry Malin Lenkeit Gesser Umeå UID UID19 design talks talks thesis bachelor bike cart Handla miljö miljövänligt fossilfritt transport transportera Carrie Malin Lenkeit Gesser UID UID19 Umeå designhögskola industridesign design examensarbete alternativ frakt frakta kandidat Environmental Management Miljöledning Vehicle Engineering Farkostteknik

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