Experiments in outdoor operation of RatSLAM

This paper shows initial results in deploying the biologically inspired Simultaneous Localisation and Mapping system, RatSLAM, in an outdoor environment. RatSLAM has been widely tested in indoor environments on the task of producing topologically coherent maps based on a fusion of odometric and visual information. This paper details the changes required to deploy RatSLAM on a small tractor equipped with odometry and an omnidirectional camera. The principal changes relate to the vision system, with others required for RatSLAM to use omnidirectional visual data. The initial results from mapping around a 500 m loop are promising, with many improvements still to be made.

Topographic studies of scalp potentials evoked by pattern presentation

The waveform and scalp distribution of the visual evoked potentials elicited by stimuli in the foveal and parafoveal regions have been investigated in a group of normal humans using a 16-channel `brain mapping' system. The waveform and topography of the responses to pattern onset and pattern reversal stimulation were investigated, using 4 x 4o full field and 4 x 2o lateral and altitudinal half-field stimuli. The responses were composed of several successive peaks which are in some respects consistent with those demonstrated by other workers using larger field sizes. The differences in the behaviour of these components with respect to the position of the stimulus in the visual field were suggestive of origins in different areas of the visual cortex and/or different visual mechanism. Of particular interest were the major early positive components `P90' and `P95' of the responses to pattern onset and pattern reversal stimulation respectively. More detailed exploration of the behaviour of these major early positive components was carried out using `M-scaled' stimuli selected to activate one square centimetre patches of striate cortex and associated extrastriate re-projections, positioned at different points in the foveal and parafoveal area of the visual field. The inter- and intra-subject variability in amplitude and localisation of the signals elicited by these targets was considered to be a reflection of the individual variations in relationship of visual field projections with the pattern of gyri and fissures on the proximal surface of the occipital lobe. The behaviour of component P90 of the onset response is consistent with a lateral origin in extrastriate visual cortex; that of P95 of the pattern reversal response is consistent in some respects with a striate cortical origin, but in others with a partial origin in extrastriate cortex.

The investigation of the primary response of the flash visual evoked response

The topographical distribution of the early components of the flash visual evoked response (VER) were investigated using a twenty channel brain mapping system. Thirty subjects, ranging in age from 21 to 84 years, had flash VERs recorded using the standard 10-20 electrode system to a balanced non-cephalic reference. The subjects were divided into three age groups: a young group, a middle group and an older group. The P2 component (positive component around 100-120 msec) of the flash VER was recorded consistently over the occipital region throughout the age range, as was a frontal negative component (N120) of about the same latency. Only the young age group had this single negative component on the frontage channels, whilst the middle age group showed an additional negative component at around 75 msec (N75). Neither group had a recordable P1 component (positive component around 60-75 msec) over the occipital region. The older age group showed both P1 and P2 components over the occipital region with the distribution of the P1 component being more widespread anteriorly. The frontal channels showed both the negative N75 and the later N120 components. The frontal negative components were shown not to be related to the electroretinogram or the balanced non-cephalic reference, but were affected by the type of stimulation. Responses recorded to both pattern reversal and onset/offset stimulation did not show the frontal negative potentials seen with flash stimulation. It was shown that the P1 component is more readily recordable in the elderly and is preceded during middle age by the development of a frontal negative component at around the same latency. The changing morphology of the negative activity in the frontal region across the age range suggests that the use of an Fz reference would produce an artificial P1 component in the middle age group and an enhancement of this component in the elderly, as well as enhance the P2 component in all ages.

Exploration of metaphors used by Indonesian legislators and political elites in the Indonesian sociopolitical domain

This thesis examines the ways Indonesian politicians exploit the rhetorical power of metaphors in the Indonesian political discourse. The research applies the Conceptual Metaphor Theory, Metaphorical Frame Analysis and Critical Discourse Analysis to textual and oral data. The corpus comprises: 150 political news articles from two newspapers (Harian Kompas and Harian Waspada, 2010-2011 edition), 30 recordings of two television news and talk-show programmes (TV-One and Metro-TV), and 20 interviews with four legislators, two educated persons and two laymen. For this study, a corpus of written bahasa Indonesia was also compiled, which comprises 150 texts of approximately 439,472 tokens. The data analysis shows the potential power of metaphors in relation to how politicians communicate the results of their thinking, reasoning and meaning-making through language and discourse and its social consequences. The data analysis firstly revealed 1155 metaphors. These metaphors were then classified into the categories of conventional metaphor, cognitive function of metaphor, metaphorical mapping and metaphor variation. The degree of conventionality of metaphors is established based on the sum of expressions in each group of metaphors. Secondly, the analysis revealed that metaphor variation is influenced by the broader Indonesian cultural context and the natural and physical environment, such as the social dimension, the regional, style and the individual. The mapping system of metaphor is unidirectionality. Thirdly, the data show that metaphoric thought pervades political discourse in relation to its uses as: (1) a felicitous tool for the rhetoric of political leaders, (2) part of meaning-making that keeps the discourse contexts alive and active, and (3) the degree to which metaphor and discourse shape the conceptual structures of politicians‟ rhetoric. Fourthly, the analysis of data revealed that the Indonesian political discourse attempts to create both distance and solidarity towards general and specific social categories accomplished via metaphorical and frame references to the conceptualisations of us/them. The result of the analysis shows that metaphor and frame are excellent indicators of the us/them categories which work dialectically in the discourse. The acts of categorisation via metaphors and frames at both textual and conceptual level activate asymmetrical concepts and contribute to social and political hierarchical constructs, i.e. WEAKNESS vs.POWER, STUDENT vs. TEACHER, GHOST vs. CHOSEN WARRIOR, and so on. This analysis underscores the dynamic nature of categories by documenting metaphorical transfers between, i.e. ENEMY, DISEASE, BUSINESS, MYSTERIOUS OBJECT and CORRUPTION, LAW, POLITICS and CASE. The metaphorical transfers showed that politicians try to dictate how they categorise each other in order to mobilise audiences to act on behalf of their ideologies and to create distance and solidarity.

Physical oceanography, sea-bed photographs and videos of benthos from the Weddell Sea taken with remote operated vehicle CHEROKEE during POLARSTERN cruise ANT-XXIII/8

The marine ecosystem on the eastern shelf of the Antarctic Peninsula was surveyed 5 and 12 years after the climate-induced collapse of the Larsen A and B ice shelves. An impoverished benthic fauna was discovered, that included deep-sea species presumed to be remnants from ice-covered conditions. The current structure of various ecosystem components appears to result from extremely different response rates to the change from an oligotrophic sub-ice-shelf ecosystem to a productive shelf ecosystem. Meiobenthic communities remained impoverished only inside the embayments. On local scales, macro- and mega-epibenthic diversity was generally low, with pioneer species and typical Antarctic megabenthic shelf species interspersed. Antarctic Minke whales and seals utilised the Larsen A/B area to feed on presumably newly established krill and pelagic fish biomass. Ecosystem impacts also extended well beyond the zone of ice-shelf collapse, with areas of high benthic disturbance resulting from scour by icebergs discharged from the Larsen embayments.

Swath sonar bathymetry during POLARSTERN cruise ARK-VII/3a (PS17) with links to multibeam raw data files

In multibeam echosounder and subbottom profiler data acquired during R/V Polarstern cruise ARK-VII/3a from the Hovgaard Ridge (Fram Strait), we found evidence for very deep (>1200 m) iceberg scouring. Five elongated seafloor features have been detected that are interpreted to be iceberg scours. The scours are oriented in north-south/south-north direction and are about 15 m deep, 300 m wide, and 4 km long crossing the entire width of the ridge. They are attributed to multiple giant paleo-icebergs that most probably left the Arctic Ocean southward through Fram Strait. The huge keel depths are indicative of ice sheets extending into the Arctic Ocean being at least 1200 m thick at the calving front during glacial maxima. The deep St. Anna Trough or grounded ice observed at the East Siberian Continental Margin are likely source regions of these icebergs that delivered freshwater to the Nordic Seas.