User Interfaces and Difference Visualizations for Alternatives

Designers often create multiple iterations to evaluate alternatives. Todays computer-based tools do not support such easy exploration of a design space, despite the fact that such support has been advocated. This dissertation is centered on this. I begin by investigating the effectiveness of various forms of difference visualizations and support for merging changes within a system targeted at diagrams with node and edge attributes. I evaluated the benefits of the introduced difference visualization techniques in two user studies. I found that the basic side-by-side juxtaposition visualization was not effective and also not well received. For comparing diagrams with matching node positions, participants preferred the side-by-side option with a difference layer. For diagrams with non-matching positions animation was beneficial, but the combination with a difference layer was preferred. Thus, the difference layer technique was useful and a good complement to animation. I continue by investigating if explicit support for design alternatives better supports exploration and creativity in a generative design system. To investigate the new techniques to better support exploration, I built a new system that supports parallel exploration of alternative designs and generation of new structural combinations. I investigate the usefulness of my prototype in two user studies and interviews. The results and feedback suggest and confirm that supporting design alternatives explicitly enables designers to work more creatively. Generative models are often represented as DAGs (directed acyclic graphs) in a dataflow programming environment. Existing approaches to compare such DAGs do not generalize to multiple alternatives. Informed by and building on the first part of my dissertation, I introduce a novel user interface that enables visual differencing and editing alternative graphsspecifically more than two alternatives simultaneously, something that has not been presented before. I also explore multi-monitor support to demonstrate that the difference visualization technique scales well to up to 18 alternatives. The novel jamming space feature makes organizing alternatives on a 23 monitor system easier. To investigate the usability of the new difference visualization method I conducted an exploratory interview with three expert designers. The received comments confirmed that it meets their design goals

Management and Visualisation of Non-linear History of Polygonal 3D Models

The research presented in this thesis concerns the problems of maintenance and revision control of large-scale three dimensional (3D) models over the Internet. As the models grow in size and the authoring tools grow in complexity, standard approaches to collaborative asset development become impractical. The prevalent paradigm of sharing files on a file system poses serious risks with regards, but not limited to, ensuring consistency and concurrency of multi-user 3D editing. Although modifications might be tracked manually using naming conventions or automatically in a version control system (VCS), understanding the provenance of a large 3D dataset is hard due to revision metadata not being associated with the underlying scene structures. Some tools and protocols enable seamless synchronisation of file and directory changes in remote locations. However, the existing web-based technologies are not yet fully exploiting the modern design patters for access to and management of alternative shared resources online. Therefore, four distinct but highly interconnected conceptual tools are explored. The first is the organisation of 3D assets within recent document-oriented No Structured Query Language (NoSQL) databases. These "schemaless" databases, unlike their relational counterparts, do not represent data in rigid table structures. Instead, they rely on polymorphic documents composed of key-value pairs that are much better suited to the diverse nature of 3D assets. Hence, a domain-specific non-linear revision control system 3D Repo is built around a NoSQL database to enable asynchronous editing similar to traditional VCSs. The second concept is that of visual 3D differencing and merging. The accompanying 3D Diff tool supports interactive conflict resolution at the level of scene graph nodes that are de facto the delta changes stored in the repository. The third is the utilisation of HyperText Transfer Protocol (HTTP) for the purposes of 3D data management. The XML3DRepo daemon application exposes the contents of the repository and the version control logic in a Representational State Transfer (REST) style of architecture. At the same time, it manifests the effects of various 3D encoding strategies on the file sizes and download times in modern web browsers. The fourth and final concept is the reverse-engineering of an editing history. Even if the models are being version controlled, the extracted provenance is limited to additions, deletions and modifications. The 3D Timeline tool, therefore, implies a plausible history of common modelling operations such as duplications, transformations, etc. Given a collection of 3D models, it estimates a part-based correspondence and visualises it in a temporal flow. The prototype tools developed as part of the research were evaluated in pilot user studies that suggest they are usable by the end users and well suited to their respective tasks. Together, the results constitute a novel framework that demonstrates the feasibility of a domain-specific 3D version control

Distinctively different: a new approach to valuing architectural amenities

We propose a method to estimate the capitalized value of the architectural design quality of a neighbourhood. Our economic design premium is identified by spatially differentiating property prices and design quality within neighbourhoods and comparing the differences across neighbourhoods. We apply our method to 47 conservation area neighbourhoods in England in which we analyse around 7900 property transactions and interview more than 500 residents. We find a capitalization effect of about 25.4% (£38.7k) associated with a one-step increase on a five-step scale ranging from not at all-distinctive to very distinctive. Our results suggest that this effect is at least partially driven by an architectural externality

People counting system using existing surveillance video camera

The Casa da Música Foundation, responsible for the management of Casa da Música do Porto building, has the need to obtain statistical data related to the number of building’s visitors. This information is a valuable tool for the elaboration of periodical reports concerning the success of this cultural institution. For this reason it was necessary to develop a system capable of returning the number of visitors for a requested period of time. This represents a complex task due to the building’s unique architectural design, characterized by very large doors and halls, and the sudden large number of people that pass through them in moments preceding and proceeding the different activities occurring in the building. To achieve the technical solution for this challenge, several image processing methods, for people detection with still cameras, were first studied. The next step was the development of a real time algorithm, using OpenCV libraries and computer vision concepts,to count individuals with the desired accuracy. This algorithm includes the scientific and technical knowledge acquired in the study of the previous methods. The themes developed in this thesis comprise the fields of background maintenance, shadow and highlight detection, and blob detection and tracking. A graphical interface was also built, to help on the development, test and tunning of the proposed system, as a complement to the work. Furthermore, tests to the system were also performed, to certify the proposed techniques against a set of limited circumstances. The results obtained revealed that the algorithm was successfully applied to count the number of people in complex environments with reliable accuracy.A Fundação Casa da Música, responsável pela gestão do edifício da Casa da Música, tem a necessidade de obter dados estatísticos relativos ao número de visitantes. Esta informação é uma ferramenta valiosa para a elaboração periódica de relatórios de afluência para a avaliação do sucesso desta instituição cultural. Por este motivo existe a necessidade da elaboração de um sistema capaz de fornecer o número de visitantes para um determinado período de tempo. Esta tarefa é dificultada pelas características arquitetônicas, únicas do edifício, com portas largas e amplos halls, e devido ao súbito número de pessoas que passam por estas áreas em momentos que antecedem e procedem concertos, ou qualquer outras actividades. Para alcançar uma solução técnica para este desafio foi inicialmente elaborado um estado da arte relativo a métodos de processamento de imagem para deteção de pessoas com câmeras de vídeo. O passo seguinte foi, utilizando bibliotecas de OpenCV e conceitos de visão computacional, o desenvolvimento de um algoritmo em tempo real para contar pessoas com a precisão desejada. Este algoritmo inclui o conhecimento científico e técnico adquirido em métodos previamente estudados. Os temas desenvolvidos nesta tese compreendem os campos de manutenção do fundo, deteção de zonas sub e sobre iluminadas e deteção e seguimento de blobs. Foi também construida uma interface gráfica para ajudar o desenvolvimento, teste e afinação do sistema proposto como complemento ao trabalho desenvolvido. Além disso, perante um conjunto limitado de circunstâncias, foram efectuados testes ao sistema em ordem a certificar as técnicas propostas. Os resultados obtidos revelaram que o algoritmo foi aplicado com sucesso para contar pessoas em ambientes complexos com precisão