Ground-Penetrating Radar (GPR) is a non-destructive electromagnetic investigative tool used in many applications across the fields of engineering and geophysics. The propagation of electromagnetic waves in lossy materials is complex and over the past 20 years, the computational modelling of GPR has developed to improve our understanding of this phenomenon. This research focuses on the development of accurate numerical models of widely-used, high-frequency commercial GPR antennas. High-frequency, highresolution GPR antennas are mainly used in civil engineering for the evaluation of structural features in concrete i. e., the location of rebars, conduits, voids and cracking. These types of target are typically located close to the surface and their responses can be coupled with the direct wave of the antenna. Most numerical simulations of GPR only include a simple excitation model, such as an infinitesimal dipole, which does not represent the actual antenna. By omitting the real antenna from the model, simulations cannot accurately replicate the amplitudes and waveshapes of real GPR responses. Numerical models of a 1.5 GHz Geophysical Survey Systems, Inc. (GSSI) antenna and a 1.2 GHz MALÅ GeoScience (MALÅ) antenna have been developed. The geometry of antennas is often complex with many fine features that must be captured in the numerical models. To visualise this level of detail in 3d, software was developed to link Paraview—an open source visualisation application which uses the Visualisation Toolkit (VTK)—with GprMax3D—electromagnetic simulation software based on the Finite-Difference Time-Domain (FDTD) method. Certain component values from the real antennas that were required for the models could not be readily determined due to commercial sensitivity. Values for these unknown parameters were found by implementing an optimisation technique known as Taguchi’s method. The metric used to initially assess the accuracy of the antenna models was a cross-corellation of the crosstalk responses from the models with the crosstalk responses measured from the real antennas. A 98 % match between modelled and real crosstalk responses was achieved. Further validation of the antenna models was undertaken using a series of laboratory experiments where oil-in-water (O/W) emulsions were created to simulate the electrical properties of real materials. The emulsions provided homogeneous liquids with controllable permittivity and conductivity and enabled different types of targets, typically encountered with GPR, to be tested. The laboratory setup was replicated in simulations which included the antenna models and an excellent agreement was shown between the measured and modelled data. The models reproduced both the amplitude and waveshape of the real responses whilst B-scans showed that the models were also accurately capturing effects, such as masking, present in the real data. It was shown that to achieve this accuracy, the real permittivity and conductivity profiles of materials must be correctly modelled. The validated antenna models were then used to investigate the radiation dynamics of GPR antennas. It was found that the shape and directivity of theoretically predicted far-field radiation patterns differ significantly from real antenna patterns. Being able to understand and visualise in 3d the antenna patterns of real GPR antennas, over realistic materials containing typical targets, is extremely important for antenna design and also from a practical user perspective.

Submitted by Luciana Ferreira (lucgeral@gmail.com) on 2014-09-29T13:53:07Z No. of bitstreams: 2 Moreira, Walison Cavalcanti-2012-dissertação.pdf: 4559977 bytes, checksum: 3e9f3100153e4d3a4775957b1445f2e7 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2014-09-29T15:11:13Z (GMT) No. of bitstreams: 2 Moreira, Walison Cavalcanti-2012-dissertação.pdf: 4559977 bytes, checksum: 3e9f3100153e4d3a4775957b1445f2e7 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Made available in DSpace on 2014-09-29T15:11:13Z (GMT). No. of bitstreams: 2 Moreira, Walison Cavalcanti-2012-dissertação.pdf: 4559977 bytes, checksum: 3e9f3100153e4d3a4775957b1445f2e7 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) Previous issue date: 2012-10-02 / Pneumonia is of the main causes of death of children under 5 years of age. Several health organizations worldwide, public and private, are engaged in investigating the disease and evaluate the effectiveness of mechanisms to prevent and combat existing. Infections causing pneumonia can be avoided. However, especially in poor countries, the resources to promote prevention are scarce. Thus the combat actions need to be very efficient and effective. To ensure the effectiveness of these actions, such as vaccines, are necessary statistical information like age range, region, period, social status and history obtained through field research. This paper proposes and implements a software architecture for the construction, use and maintenance of research of childhood pneumonias. The techniques, technologies, tools and services used in defining the architecture were chosen with a focus on low cost. This way is much more feasible to use software for automated search systems by healthcare entities that have few financial resources. / As pneumonias estão entre as principais causas de morte das crianças com menos de 5 anos de idade. Várias entidades de saúde no mundo todo, públicas e privadas, estão empenhadas em investigar a doença e avaliar a eficiência dos mecanismos de prevenção e combate existentes. As infecções que causam pneumonia podem ser evitadas. No entanto, principalmente em países pobres, os recursos para promover a prevenção são escassos. Assim as ações de combate precisam ser muito eficientes e eficazes. Para garantir a efetividade dessas ações, como as vacinas, são necessárias informações estatísticas como faixa etária, região, época, condição social e histórico obtido através de pesquisa em campo. Este trabalho propõe e implementa uma arquitetura de software para construção, uso e manutenção de sistemas de pesquisa das pneumonias na infância. As técnicas, tecnologias, ferramentas e serviços utilizados na definição da arquitetura foram escolhidos com foco no baixo custo. Dessa forma fica muito mais viável a utilização de softwares para sistemas de pesquisa automatizados por entidades de saúde que possuem poucos recursos financeiros. Palavras

At KTH, students who want to start their degree project must complete a paper form called “UT-EXAR: Ansökan om examensarbete/application for degree project”. The form is used to determine students’ eligibility to start a degree project, as well as potential examiners for the project. After the form is filled in and signed by multiple parties, a student can initiate his or her degree project. However, due to the excessively time-consuming process of completing the form, an alternative solution was proposed: a survey in the Canvas Learning Management System (LMS) that replace s the UT-EXAR form. Although the survey reduces the time required by students to provide information and find examiners, it is by no means the most efficient solution. The survey suffers from multiple flaws, such as asking students to answer unnecessary questions, and for certain questions, presenting students with more alternatives than necessary. The survey also fails to automatically organize the data collected from the students’ answers; hence administrators must manually enter the data into a spreadsheet or other record. This thesis proposes an optimized solution to the problem by introducing a dynamic survey. Moreover, this dynamic survey uses the Canvas Representational State Transfer (REST) API to access students’ program-specific data. Additionally, this survey can use data provided by students when answering the survey questions to dynamically construct questions for each individual student as well as using information from other KTH systems to dynamically construct customized alternatives for each individual student. This solution effectively prevents the survey from presenting students with questions and choices that are irrelevant to their individual case. Furthermore, the proposed solution directly inserts the data collected from the students into a Canvas Gradebook. In order to implement and test the proposed solution, a version of the Canvas LMS was created by virtualizing each Canvas-based microservice inside of a Docker container and allowing the containers to communicate over a network. Furthermore, the survey itself used the Learning Tools Interoperability (LTI) standard. When testing the solution, it was seen that the survey has not only successfully managed to filter the questions and alternative answers based on the user’s data, but also showed great potential to be more efficient than a survey with statically-presented data. The survey effectively automates the insertion of the data into the gradebook. / På KTH, studenter som skall påbörja sitt examensarbete måste fylla i en blankett som kallas “UT-EXAR: Ansökan om examensarbete/application for degree project”. Blanketten används för att bestämma studenters behörighet för att göra examensarbete, samt potentiella examinator för projektet. Efter att blanketten är fylld och undertecknad av flera parter kan en student påbörja sitt examensarbete. Emellertid, på grund av den alltför tidskrävande processen med att fylla blanketten, var en alternativ lösning föreslås: en särskild undersökning i Canvas Lärplattform (eng. Learning Management System(LMS)) som fungerar som ersättare för UT-EXAR-formulär. Trots att undersökningen har lyckats minska den tid som krävs av studetenter för att ge information och hitta examinator, det är inte den mest effektiva lösningen. Undersökningen lider av flera brister, såsom att få studenterna att svara på fler frågor än vad som behövs, och för vissa frågor, presenterar studenter med fler svarsalternativ än nödvändigt. Undersökningen inte heller automatiskt med att organisera data som samlats in från studenters svar. Som ett resultat skulle en administratör behöva organisera data manuellt i ett kalkylblad. Detta examensarbete föreslår en mer optimerad lösning på problemet: omskrivning av undersökningens funktionaliteter för att använda Representational State Transfer(REST) API för att komma åt studenters programspecifika data i back-end, såväl att använda speciella haschar för att hålla referenser till uppgifter som lämnas av studenterna när de svarar på frågorna i undersökningen, så att undersökningen inte bara kan använda dessa data för att dynamiskt konstruera frågor för varje enskild student, men också dynamiskt konstruera svarsalternativ för varje enskild student. Denna lösning förhindrar effektivt undersökningen från att presentera studenter med frågor och valbara svarsalternativ som är helt irrelevanta för var och en av deras individuella fall. Med den föreslagna lösningen kommer undersökningen dessutom att kunna organisera de data som samlats in från Studenterna till ett speciellt Canvas-baserat kalkyllblad, kallas som Betygsbok. För att genomföra och testa den förslagna lösningen skapades en testbar version av Canvas LMS genom att virtualisera varje Canvas-baserad mikroservice inuti en dockercontainer och tillåter containers att kommunicera över ett nätverk. Dessutom var undersökningen själv konfigurerad för att använda Lärverktyg Interoperability (LTI) standard. Vid testning av lösningen, det visade sig att undersökningen på ett sätt effektivt har lyckats använda vissa uppgifter från en testanvändare att bara endast svara på de relevanta frågorna, men också presentera användaren med en mer kondenserad lista svarsalternativ över baserat på data.<p>