title: Comparing static Gantt and mosaic charts for visualization of task schedules

authors: Luz, Saturnino

subjects: computer science

abstract: A mosaic chart has been proposed for representation of events on a timeline. While early studies demonstrated the effectiveness of mosaics in supporting visualization of multimedia records on a meeting browser, the usability of mosaics as a static timeline visualization has not been studied in more general settings. This paper investigates the use of the mosaic charts for visualization of project schedules. A user study was conducted to compare a building project schedule encoded alternatively as a mosaic or as a Gantt chart. Although the study focused on static graphs, for which the Gantt technique is usually very effective, results showed that the users were as fast and accurate at answering the questions using the mosaic representation as they were using Gantt charts. The analysis and experiment indicated algorithmic, space-filling and interpretation limitations of the mosaic technique. We suggest possible design improvements to overcome some of these limitations.

text: Comparing static Gantt and mosaic charts for visualization of task schedules A mosaic chart has been proposed for representation of events on a timeline. While early studies demonstrated the effectiveness of mosaics in supporting visualization of multimedia records on a meeting browser, the usability of mosaics as a static timeline visualization has not been studied in more general settings. This paper investigates the use of the mosaic charts for visualization of project schedules. A user study was conducted to compare a building project schedule encoded alternatively as a mosaic or as a Gantt chart. Although the study focused on static graphs, for which the Gantt technique is usually very effective, results showed that the users were as fast and accurate at answering the questions using the mosaic representation as they were using Gantt charts. The analysis and experiment indicated algorithmic, space-filling and interpretation limitations of the mosaic technique. We suggest possible design improvements to overcome some of these limitations.

year: 2011

title: Extreme value modelling for forecasting market crisis impacts

authors: Zhao, Xin

abstract: This article introduces a new approach for estimating Value at Risk (VaR), which is then used to show the likelihood of the impacts of the current financial crisis. A commonly used two-stage approach is taken, by combining a Generalized Autoregressive Conditional Heteroscedasticity (GARCH) volatility model with a novel extreme value mixture model for the innovations. The proposed mixture model permits any distribution function for the main mode of the innovations, with the very flexible Generalized Pareto Distribution (GPD) for the upper and lower tails. A major advance with the mixture model is that it overcomes the problems with threshold choice in traditional methods as it is treated as a parameter in the model to be estimated. The model describes the tail distribution of both the losses and gains simultaneously, which is natural for financial applications. As the threshold is treated as a parameter, the uncertainty from its estimation is accounted for, which is a challenging and often overlooked problem in traditional approaches. The model is shown to be sufficiently flexible that it can be directly applied to reliably estimate the likelihood of impact of the financial crisis on stock and index returns.

text: Extreme value modelling for forecasting market crisis impacts This article introduces a new approach for estimating Value at Risk (VaR), which is then used to show the likelihood of the impacts of the current financial crisis. A commonly used two-stage approach is taken, by combining a Generalized Autoregressive Conditional Heteroscedasticity (GARCH) volatility model with a novel extreme value mixture model for the innovations. The proposed mixture model permits any distribution function for the main mode of the innovations, with the very flexible Generalized Pareto Distribution (GPD) for the upper and lower tails. A major advance with the mixture model is that it overcomes the problems with threshold choice in traditional methods as it is treated as a parameter in the model to be estimated. The model describes the tail distribution of both the losses and gains simultaneously, which is natural for financial applications. As the threshold is treated as a parameter, the uncertainty from its estimation is accounted for, which is a challenging and often overlooked problem in traditional approaches. The model is shown to be sufficiently flexible that it can be directly applied to reliably estimate the likelihood of impact of the financial crisis on stock and index returns.

year: 2010

title: Matariki, commodity culture, and multiple identities

authors: Hardy, Ann

subjects: Matariki

abstract: The event known as Matariki, the rising of the Pleiades in winter, which Māori take as the mark of the beginning of a new year, was not a strong feature of the wider public sphere for most of the 20th century. Since 2001, however, when Te Taura Whiri, the Māori Language Commission, published an explanatory booklet with the aim of reviving interest in Matariki as an aide to the maintenance of te reo, it has been promoted by several quasi-governmental institutions, especially the national museum, Te Papa, as a winter festival for all New Zealanders. Its main public presence to date has been through media products: posters, banners, websites, television programmes, newspaper features, calendars, some theatrical performances and physical commemoration ceremonies.

The larger project, of which this paper represents an initial descriptive and positioning phase, is a continuation of the researcher's long-standing interest in the intersections of religiosity, culture, and media as they are active in the environment of Aotearoa New Zealand. It assumes, building on theorists such as Bellah and Lundby that the creation of such festivals is an act of 'civil religiosity' that attempts to create and strengthen national community around a set of numinous symbols.
However, the development of an enterprise such as Matariki is pursued in a complex political field, where broad agreement across various factions is needed before the festival can take on an enduring material and symbolic existence. In investigating the factors that will determine the future of Matariki it is relevant to consider the interaction of three factors in particular: the ethno-political history of New Zealand; the characteristics of contemporary reflexive spirituality, which are intertwined with commodificatory tendencies and thirdly, the impacts of increasing globalisation on the parameters of identity-formation for citizens in late-modern societies.

text: Matariki, commodity culture, and multiple identities The event known as Matariki, the rising of the Pleiades in winter, which Māori take as the mark of the beginning of a new year, was not a strong feature of the wider public sphere for most of the 20th century. Since 2001, however, when Te Taura Whiri, the Māori Language Commission, published an explanatory booklet with the aim of reviving interest in Matariki as an aide to the maintenance of te reo, it has been promoted by several quasi-governmental institutions, especially the national museum, Te Papa, as a winter festival for all New Zealanders. Its main public presence to date has been through media products: posters, banners, websites, television programmes, newspaper features, calendars, some theatrical performances and physical commemoration ceremonies.

The larger project, of which this paper represents an initial descriptive and positioning phase, is a continuation of the researcher's long-standing interest in the intersections of religiosity, culture, and media as they are active in the environment of Aotearoa New Zealand. It assumes, building on theorists such as Bellah and Lundby that the creation of such festivals is an act of 'civil religiosity' that attempts to create and strengthen national community around a set of numinous symbols.
However, the development of an enterprise such as Matariki is pursued in a complex political field, where broad agreement across various factions is needed before the festival can take on an enduring material and symbolic existence. In investigating the factors that will determine the future of Matariki it is relevant to consider the interaction of three factors in particular: the ethno-political history of New Zealand; the characteristics of contemporary reflexive spirituality, which are intertwined with commodificatory tendencies and thirdly, the impacts of increasing globalisation on the parameters of identity-formation for citizens in late-modern societies.

year: 2011