In this thesis a study of computing systems that use time as the primary method of organising electronic documents, and versions of electronic documents, is presented. Such systems should be useful and usable because they exploit people's intuitive understanding of temporal order. In addition, the systems are worthy of investigation because they have received little attention, yet they may provide enormous benefits to users with little cost, as the temporal information is easy for systems to record. Temporal document organisation systems have the potential of alleviating many of the problems that traditional systems have had for decades. Throughout this thesis, user-interface guidelines for the implementation of temporal document-organisation systems are presented. The guidelines are based on empirical and theoretical evaluations that I have conducted, and studies of other's work. By using theses guidelines, designers should be able to create interfaces that are liked by users, and provide good support for the user's tasks. The first set of guidelines are based on an investigation of the human factors of temporal document-organisation, specifically looking at memory and temporal awareness. These human factors are related to the user's tasks with documents and document versions: finding, reminding, error-recovery and system exploration. Another set of guidelines, based on a study of how existing document-organisation systems support the user's tasks, are then presented. My first empirical evaluation looks at history lists, which are some of the most common temporal document-organisation interfaces that are found today. In the study it was found that participants are slower at retrieving Web pages when using an interface that broke the history into non-temporal categories than with the other three interfaces that were tested. In addition the participants preferred the interface that broke the history into 'temporal chunks'. Following on from the history-list evaluation, a theoretical and empirical evaluation of version retrieval systems, including undo, is presented. It was found that, in a text-editing environment, there is sufficient mechanical reason son for forward error-correction to be favoured over undo when correcting small and simple errors. For more complex errors, it was found that a visualisation of the prior document versions is better than forward error-correction and undo. In a similar evaluation of error recovery in a drawing editor, undo was found to be the quickest method of recovering from simple errors, while a visualisation of the prior document versions allowed for faster recovery from more complex errors. Having looked at the retrieval of documents and document-versions separately, my final study looks at a system that combines them both. The system that I developed organises documents without the need for file names and folders, which are used in most document organisation systems. In the formative study I found that the system that combines the retrieval of documents and document versions is useful and usable, and the organisation of the data did not confuse the participants. After each of the evaluations, I provide guidelines that should be applicable not only to the interfaces that were studied, but to temporal document organisation interfaces in general.

Este documento apresenta um estudo que avalia o uso de informação temporal na tarefa de recomendação de tweets no twitter. Foram explorados dois aspectos temporais: a vida útil de tópico de informação e a sua versão personalizada para cada usuário. A aplicação destes aspectos temporais foi avaliada utilizando-se três sistemas de recomendação implementados. Também avaliamos dois modelos de tópicos utilizados para representar tweets: o modelo bag of words e um modelo de tópicos latentes extraídos por LDA (Latent Dirichlet Allocation). Além disso, avaliamos o uso de máquinas de vetor de suporte para estimar o perfil de interesses de usuário, comparando esta abordagem com uma outra mais simples. Os experimentos foram executados utilizando-se um conjunto de dados com 414 milhões de tweets publicados por 321 mil usuários. Os resultados apresentados demonstram que o uso de vida útil de tópico na tarefa de recomendação melhora a qualidade das recomendações, e o uso da versão personalizada desta informação melhorou ainda mais a qualidade destas / This document presents a study that evaluates the use of temporal information in the task of recommending tweets on Twitter. Two temporal aspects have been analysed: the lifespan of information topic and its personalized version for each user. The application of such temporal aspects has been evaluated using three recommendation systems implemented in this work. We also evaluated two topic models considered to describe tweets: a bag of words model and a model of latent topics extracted using LDA (Latent Dirichlet Allocation). Furthermore, we evaluated the use of SVM (Support Vector Machines) to estimate the user profile, comparing this approach with a simpler one. The experiments have been executed using a dataset with 414 millions of tweets published by 321 thousands of users. The results show that the use of topic lifespan information increases the quality of recommendation, and the personalized version of this information increases the quality even more

Este documento apresenta um estudo que avalia o uso de informação temporal na tarefa de recomendação de tweets no twitter. Foram explorados dois aspectos temporais: a vida útil de tópico de informação e a sua versão personalizada para cada usuário. A aplicação destes aspectos temporais foi avaliada utilizando-se três sistemas de recomendação implementados. Também avaliamos dois modelos de tópicos utilizados para representar tweets: o modelo bag of words e um modelo de tópicos latentes extraídos por LDA (Latent Dirichlet Allocation). Além disso, avaliamos o uso de máquinas de vetor de suporte para estimar o perfil de interesses de usuário, comparando esta abordagem com uma outra mais simples. Os experimentos foram executados utilizando-se um conjunto de dados com 414 milhões de tweets publicados por 321 mil usuários. Os resultados apresentados demonstram que o uso de vida útil de tópico na tarefa de recomendação melhora a qualidade das recomendações, e o uso da versão personalizada desta informação melhorou ainda mais a qualidade destas / This document presents a study that evaluates the use of temporal information in the task of recommending tweets on Twitter. Two temporal aspects have been analysed: the lifespan of information topic and its personalized version for each user. The application of such temporal aspects has been evaluated using three recommendation systems implemented in this work. We also evaluated two topic models considered to describe tweets: a bag of words model and a model of latent topics extracted using LDA (Latent Dirichlet Allocation). Furthermore, we evaluated the use of SVM (Support Vector Machines) to estimate the user profile, comparing this approach with a simpler one. The experiments have been executed using a dataset with 414 millions of tweets published by 321 thousands of users. The results show that the use of topic lifespan information increases the quality of recommendation, and the personalized version of this information increases the quality even more

Educational restructuring is an international phenomenon, which emphasizes flexibility, local decision-making, self-regulation and innovation in contrast to previous bureaucratic governing and standardised teaching. Current reforms aim at a school adapted to the emerging information- and knowledge intensive society. The aim of the dissertation is to examine current curriculum reforms concerning the governing and organisation of time in compulsory school. In what ways is the temporal order of schools changing in a late modern post-industrial society? What new conditions for teaching are these changes implicating? What kinds of dilemmas emerge for different school actors in conducting these reforms? By using critical discourse analysis, educational reforms are studied as a dynamic discursive practice with different concurring imperatives formatted in tension fields of cultural, social and political changes. Four case studies are used to explore how a current Swedish curriculum reform, Without a National Timetable in Compulsory School, was conducted in an experiment period over five years. The local appropriation of the policy intentions was found to depend on: (i) the preparedness of reform within the particular school, (ii) the dominant school culture, (iii) the local decision-making processes, and (iv) variations in reform mobilisation (identified in the case studies as micro-political struggle, resistance by evasiveness, preservation of consensus and stratification). The results demonstrate that curriculum reform, the ongoing movement of educational restructuring, is not a linear unambiguous process of application. On the contrary, it is a discursive arena, which has a great impact as it involves discourses of efficiency and quality development, increased professionalism, economical cost-reduction, choice and devolution. These discourses involve concurring imperatives for school actors to handle time in the organisation of teaching dependent upon how they are positioned as (i) effective ‘goals makers’ (ii) problem-solvers, who remove obstacles for individual learning projects, (iii) strategists in a more competitive educational landscape, (iv) and moral agents, who in deliberation with others work towards a fair and equal school. It is concluded that for school actors, who work under the crossfire of educational restructuring, these imperatives pose a number of complex dilemmas.