Special Issue : Highlights from the ITS European Congress in Glasgow (2016)

Peer reviewedPostprin

Customizing kernel functions for SVM-based hyperspectral image classification

Previous research applying kernel methods such as support vector machines (SVMs) to hyperspectral image classification has achieved performance competitive with the best available algorithms. However, few efforts have been made to extend SVMs to cover the specific requirements of hyperspectral image classification, for example, by building tailor-made kernels. Observation of real-life spectral imagery from the AVIRIS hyperspectral sensor shows that the useful information for classification is not equally distributed across bands, which provides potential to enhance the SVM's performance through exploring different kernel functions. Spectrally weighted kernels are, therefore, proposed, and a set of particular weights is chosen by either optimizing an estimate of generalization error or evaluating each band's utility level. To assess the effectiveness of the proposed method, experiments are carried out on the publicly available 92AV3C dataset collected from the 220-dimensional AVIRIS hyperspectral sensor. Results indicate that the method is generally effective in improving performance: spectral weighting based on learning weights by gradient descent is found to be slightly better than an alternative method based on estimating ";relevance"; between band information and ground trut

Adaptive Governance: An Introduction and Implications for Public Policy

Adaptive governance is a concept from institutional theory that deals with the evolution of institutions for the management of shared assets, particularly common pool resources and other forms of natural capital. This paper is the first of a set of four papers on adaptive governance, providing a brief overview of the history of the concept, the distinguishing features of the literature, and key insights provided for economists and policy advisors. We argue that adaptive governance provides an interesting lens for examining the political economy of policy responses akin to the concept of market failure within economics, but applied to wider processes of social learning and collective choice, including collective choices about the scope and structure of institutions that govern lower level choices by individuals and organizations.adaptive governance, public policy, common pool resources, natural resource management, wicked problems, Institutional and Behavioral Economics,

A tool to aid redesign of flexible transport services to increase efficiency in rural transport service provision

This research was supported by the Research Councils UK Digital Economy programme award (reference: EP/G066051/1) to the dot.rural Digital Economy Hub, at the University of Aberdeen.Peer reviewedPublisher PD

Measuring Positions of Objects using Two or More Cameras

An improved method of computing positions of objects from digitized images acquired by two or more cameras (see figure) has been developed for use in tracking debris shed by a spacecraft during and shortly after launch. The method is also readily adaptable to such applications as (1) tracking moving and possibly interacting objects in other settings in order to determine causes of accidents and (2) measuring positions of stationary objects, as in surveying. Images acquired by cameras fixed to the ground and/or cameras mounted on tracking telescopes can be used in this method. In this method, processing of image data starts with creation of detailed computer- aided design (CAD) models of the objects to be tracked. By rotating, translating, resizing, and overlaying the models with digitized camera images, parameters that characterize the position and orientation of the camera can be determined. The final position error depends on how well the centroids of the objects in the images are measured; how accurately the centroids are interpolated for synchronization of cameras; and how effectively matches are made to determine rotation, scaling, and translation parameters. The method involves use of the perspective camera model (also denoted the point camera model), which is one of several mathematical models developed over the years to represent the relationships between external coordinates of objects and the coordinates of the objects as they appear on the image plane in a camera. The method also involves extensive use of the affine camera model, in which the distance from the camera to an object (or to a small feature on an object) is assumed to be much greater than the size of the object (or feature), resulting in a truly two-dimensional image. The affine camera model does not require advance knowledge of the positions and orientations of the cameras. This is because ultimately, positions and orientations of the cameras and of all objects are computed in a coordinate system attached to one object as defined in its CAD model

Storm intensity and old-growth forest disturbances in the Amazon region

We analyzed the pattern of large forest disturbances or blow-downs apparently caused by severe storms in a mostly unmanaged portion of the Brazilian Amazon using 27 Landsat images and daily precipitation estimates from NOAA satellite data. For each Landsat a spectral mixture analysis (SMA) was applied. Based on SMA, we detected and mapped 279 patches (from 5 ha to 2,223 ha) characteristic of blow-downs. A total of 21,931 ha of forest were disturbed. We found a strong correlation between occurrence of blow-downs and frequency of heavy rainfall (Spearman\u27s rank, r2 = 0.84, p \u3c 0.0003). The recurrence intervals of large disturbances were estimated to be 90,000 yr for the eastern Amazon and 27,000 yr for the western Amazon. This suggests that weather patterns affect the frequency of large forest disturbances that may produce different rates of forest turnover in the eastern and western Amazon basin

Rapid Adaptation to Mammalian Sociality via Sexually Selected Traits

Background: Laboratory studies show that the sexual selection via mate choice and intrasexual competition can profoundly affect the development and fitness of offspring. Less is known, however, about the total effects of sexual selection on offspring in normal social conditions. For many animals, opportunity for mating success is determined by complex social interactions, such as dominance hierarchies. Social selection is an extended view of sexual selection that incorporates competition during sexual and nonsexual interactions, and predicts complex evolutionary dynamics. Whether social selection improves or constrains offspring fitness is controversial. Results: To characterize the consequences of social selection, we introduced wild-derived mice to seminatural competition for three consecutive generations (promiscuous lineage). In parallel, we bred a control lineage in cages using random mate assignment (monogamous lineage). A direct competition experiment using second-generation animals revealed that promiscuous line males had greater reproductive success than monogamous line males (particularly during extrapair matings), in spite of higher mortality and equivalent success in social dominance and sperm competition. There were no major female fitness effects, though promiscuous line females had fewer litters than monogamous line females. We confirmed a behavioral sexual attraction mechanism by showing that, when given a choice, females had both odor and mating preferences for promiscuous line over monogamous line males. Conclusions: Our study demonstrates novel evidence for the strength of sexual selection under normal social conditions, and shows rapid male adaptation to sociality driven largely by sexual trait expression, with tradeoffs in survivorship and female fecundity. The speed at which these phenotypes emerged suggests the possibility of transgenerational inheritance. Mouse population densities fluctuate dramatically in nature, and we propose that sexually selected phenotypes arise dynamically during periods of social competition.Molecular and Cellular Biolog

Family memories in the home: contrasting physical and digital mementos

We carried out fieldwork to characterise and compare physical and digital mementos in the home. Physical mementos are highly valued, heterogeneous and support different types of recollection. Contrary to expectations, we found physical mementos are not purely representational, and can involve appropriating common objects and more idiosyncratic forms. In contrast, digital mementos were initially perceived as less valuable, although participants later reconsidered this. Digital mementos were somewhat limited in function and expression, largely involving representational photos and videos, and infrequently accessed. We explain these digital limitations and conclude with design guidelines for digital mementos, including better techniques for accessing and integrating these into everyday life, allowing them to acquire the symbolic associations and lasting value that characterise their physical counterparts