Data-driven estimation of building interior plans

This work investigates constructing plans of building interiors using learned building measurements. In particular, we address the problem of accurately estimating dimensions of rooms when measurements of the interior space have not been captured. Our approach focuses on learning the geometry, orientation and occurrence of rooms from a corpus of real-world building plan data to form a predictive model. The trained predictive model may then be queried to generate estimates of room dimensions and orientations. These estimates are then integrated with the overall building footprint and iteratively improved using a two-stage optimisation process to form complete interior plans.

The approach is presented as a semi-automatic method for constructing plans which can cope with a limited set of known information and constructs likely representations of building plans through modelling of soft and hard constraints. We evaluate the method in the context of estimating residential house plans and demonstrate that predictions can effectively be used for constructing plans given limited prior knowledge about the types of rooms and their topology.     

Environmental economic geography: A sympathetic critique

In this article I examine the objectives and substantive claims of a body of work that has come to be known as ‘environmental economic geography’ (EEG). I characterize this loose grouping of research activities as a topical contrivance: often what unites EEG researchers is simply a desire to apply the theories and methods of economic geography to environmental issues. The article explores an alternative rationale for doing EEG: the development of a distinctive intellectual project out of the encounter between economic geography and environment. Such a project extends beyond an assessment of the environmental impacts of economic activity, to examine the ways in which many ‘economic’ processes are environmentally constituted.     

Global Resource Assessments of Primary Metals: An Optimistic Reality Check

The mining of primary metals is critical for a range of modern infrastructure and goods and the continuing growth in global population and consumption means that these primary metals are expected to remain in high demand. However, metallic deposits are, in essence, finite and non-renewable—leading to some concern that we may run out of a given metal in the future. Here, we address this concern by presenting a brief review of the reporting of mineral resource estimates, compiling detailed datasets for national and global trends in mineral resources for numerous metals, and present detailed case studies of major mining projects or fields. The evidence clearly shows strong growth in known mineral resources and cumulative production over time rather than any evidence of gradual resource depletion. In addition, the key factors that already govern existing mining projects and mineral resources are certainly social, environmental and economic in nature rather than geological or related to physical resource depletion. Overall, there is great room for optimism in terms of humankind’s ability to supply future generations with the metals they will require.     

Chronology,stratigraphy and palaeoenvironmental interpretation of a Late Pleistocene to mid‐Holocene cave accumulation on Kangaroo Island,South Australia

Chronological, sedimentological and geochemical analyses of a clastic infill from Kelly Hill Cave (5K1), Kangaroo Island, document a palaeoenvironmental record that spans from the Late Pleistocene to the middle Holocene. We AMS radiocarbon‐dated bone collagen and U–Th‐dated speleothem to determine that fossiliferous sediments were deposited between >20 ka and 7 ka ago. Most of the 15 sedimentary layers are dominated by sand‐ and silt‐sized quartz that is physically and geochemically comparable with surface soils in the Kelly Hill area. Late Pleistocene and Last Glacial Maximum strata are represented primarily by homogeneous, poorly sorted quartz‐rich sediments that contain little organic matter, but include a thin layer composed largely of silt‐sized clay pellets that resemble sediments deflated from playa lakes. Microstructures observed in petrographic slides indicate that, with the exception of one layer, all sediments experienced little reworking once deposited in the cave. Some layers display pedogenic microstructures such as redeposited clays and opaline silica infilling that indicate postdepositional modification; that is, cave‐floor soil development. Overlying Holocene‐aged sediments also consist mainly of quartz but have much greater organic matter content. Some of these sediments have been strongly influenced by re‐precipitated organic matter that appears to have been transported into the cave via vadose drip water. The presence of dissolved organic matter in soil/vadose waters suggests a high vegetation density and acidic soils, which are congruent with the more equitable climatic conditions characteristic of the Holocene. The sediments described here provide a valuable palaeoenvironmental record that will facilitate future interpretation of associated vertebrate fossils.     

Design Charts for the Stability Analysis of Unsaturated Soil Slopes

Simple limit equilibrium analyses can be performed to determine the Factor of Safety (FOS) against slope failure of unsaturated soil slopes. However, many of the input parameters needed for these analyses are highly variable, and the FOS value obtained is critically dependent on assumptions made by the designer. This paper describes a suite of reliability analyses on unsaturated soil slopes performed using an invariant reliability model. The results are presented in design charts from which a designer can choose the FOS value required to ensure a given target reliability index for a slope. The approach ensures that despite the variability of input parameters the slope will have a probability of failure of 2.23% or less.     

Physiological and isotopic responses of scleractinian corals to ocean acidification

Uptake of anthropogenic CO₂ by the oceans is altering seawater chemistry with potentially serious consequences for coral reef ecosystems due to the reduction of seawater pH and aragonite saturation state (Ω_arag). The objectives of this long-term study were to investigate the viability of two ecologically important reef-building coral species, massive Porites sp. and Stylophora pistillata, exposed to high pCO₂ (or low pH) conditions and to observe possible changes in physiologically related parameters as well as skeletal isotopic composition. Fragments of Porites sp. and S. pistillata were kept for 6-14 months under controlled aquarium conditions characterized by normal and elevated pCO₂ conditions, corresponding to pH_T values of 8.09, 7.49, and 7.19, respectively. In contrast with shorter, and therefore more transient experiments, the long experimental timescale achieved in this study ensures complete equilibration and steady state with the experimental environment and guarantees that the data provide insights into viable and stably growing corals. During the experiments, all coral fragments survived and added new skeleton, even at seawater Ω_arag < 1, implying that the coral skeleton is formed by mechanisms under strong biological control. Measurements of boron (B), carbon (C), and oxygen (O) isotopic composition of skeleton, C isotopic composition of coral tissue and symbiont zooxanthellae, along with physiological data (such as skeletal growth, tissue biomass, zooxanthellae cell density, and chlorophyll concentration) allow for a direct comparison with corals living under normal conditions and sampled simultaneously. Skeletal growth and zooxanthellae density were found to decrease, whereas coral tissue biomass (measured as protein concentration) and zooxanthellae chlorophyll concentrations increased under high pCO₂ (low pH) conditions. Both species showed similar trends of δ¹¹B depletion and δ¹⁸O enrichment under reduced pH, whereas the δ¹³C results imply species-specific metabolic response to high pCO₂ conditions. The skeletal δ¹¹B values plot above seawater δ¹¹B vs. pH borate fractionation curves calculated using either the theoretically derived α_B value of 1.0194 (Kakihana et al. (1977) Bull. Chem. Soc. Jpn.50, 158) or the empirical α_B value of 1.0272 (Klochko et al. (2006) EPSL248, 261). However, the effective α_B must be greater than 1.0200 in order to yield calculated coral skeletal δ¹¹B values for pH conditions where Ω_arag ? 1. The δ¹¹B vs. pH offset from the seawater δ¹¹B vs. pH fractionation curves suggests a change in the ratio of skeletal material laid down during dark and light calcification and/or an internal pH regulation, presumably controlled by ion-transport enzymes. Finally, seawater pH significantly influences skeletal δ¹³C and δ¹⁸O. This must be taken into consideration when reconstructing paleo-environmental conditions from coral skeletons.     

Geographies of peak oil: The other carbon problem

This extended editorial introduction to a themed issue of Geoforum on geographies of peak oil has three objectives. First, it provides a concise account of the ’peak oil’ claim, identifying the key protagonists in the debate, and outlining different stances with regard to the timing, shape and composition (conventional vs. non-conventional hydrocarbons) of the peak. Second, after briefly characterising the limited engagement with peak oil by human geographers, it offers a provisional set of claims about what a geographical analysis of peak oil might yield. Finally, it introduces each of the papers and, in doing so, makes the case for a fuller and more sustained engagement by geography with this ’other carbon problem.’     

Magnetic field fossilization and tail reconfiguration in Titan's plasma environment during a magnetopause passage: 3D adaptive hybrid code simulations

We present a hybrid simulation study (kinetic ions, fluid electrons) of Titan's plasma interaction during an excursion of this moon from Saturn's magnetosphere into its magnetosheath, as observed for the first time during Cassini's T32 flyby on 13 June 2007. In contrast to earlier simulations of Titan's plasma environment under non-stationary upstream conditions, our model considers a difference in the flow directions of magnetospheric and magnetosheath plasma. Two complementary scenarios are investigated, with the flow directions of the impinging magnetospheric/magnetosheath plasmas being (A) antiparallel and (B) parallel. In both cases, our simulations show that due to the drastically reduced convection speed in the slow and dense heavy ion plasma near Titan, the satellite carries a bundle of “fossilized” magnetic field lines from the magnetosphere in the magnetosheath. Furthermore, the passage through Saturn's magnetopause goes along with a disruption of Titan's pick-up tail. Although the tail is not detached from the satellite, large clouds of heavy ion plasma are stripped of its outer flank, featuring a wave-like pattern. Whereas in case (B) under parallel flow conditions there is only a small retardation of about 5 min between the passage of Titan through the magnetopause and the reconfiguration of the pick-up tail, the tail reconfiguration in the case (A) scenario is completed not until 25 min after the magnetopause passage. The lifetime of fossil fields in the moon's ionosphere is approximately 25 min, regardless of whether parallel or antiparallel flow conditions are applied.