Dynamic ensemble selection methods for heterogeneous data mining

Big data is often collected from multiple sources with possibly different features, representations and granularity and hence is defined as heterogeneous data. Such multiple datasets need to be fused together in some ways for further analysis. Data fusion at feature level requires domain knowledge and can be time-consuming and ineffective, but it could be avoided if decision-level fusion is applied properly. Ensemble methods appear to be an appropriate paradigm to do just that as each subset of heterogeneous data sources can be separately used to induce models independently and their decisions are then aggregated by a decision fusion function in an ensemble. This study investigates how heterogeneous data can be used to generate more diverse classifiers to build more accurate ensembles. A Dynamic Ensemble Selection Optimisation (DESO) framework is proposed, using the local feature space of heterogeneous data to increase diversity among classifiers and Simulated Annealing for optimisation. An implementation example of DESO — BaggingDES is provided with Bagging as a base platform of DESO, to test its performance and also explore the relationship between diversity and accuracy. Experiments are carried out with some heterogeneous datasets derived from real-world benchmark datasets. The statistical analyses of the results show that BaggingDES performed significantly better than the baseline method — decision tree, and reasonably better than the classic Bagging.and accuracy. Experiments were carried out with some heterogeneous datasets derived from real-world benchmark datasets. The statistical analyses of the results show that BaggingDES performed significantly better than the baseline method - decision tree, and reasonably better than the classic Bagging

Foreign Bodies: Oceania and the Science of Race 1750-1940

From the 18th century, Oceania became the principal laboratory of raciology for scholars, voyagers, and colonisers alike. By juxtaposing encounters and theory, this magisterial book explores the semantics of human difference in all its emotional, intellectual, religious, and practical dimensions. The argument developed is subtle, engrossing, and gives the paradigm of ‘race’ its full use value. Foreign Bodies is a model of analysis and erudition from which historians of science and everyone interested in intercultural relations will greatly profit. Claude Blanckaert, CNRS (Centre Alexandre Koyré), Paris, and Honorary President, French Society for the History of the Science of Ma

Monitoring the environmental impact of mining in remote locations through remotely sensed data

Mining is an integral part of the development of many countries in the Asia-Pacific region and is associated with adverse environmental and social impacts. The monitoring of mining in remote locations is problematic due to difficulties of access. Satellite remote sensing is able to provide information on landscape transformation in a cost-effective way around large-scale mines. The PT Freeport Indonesia mine in Papua (Indonesia) is the world's largest copper-gold mine and previous studies have documented a range of impacts. A multi-temporal analysis of Landsat 5 imagery of the Freeport area was undertaken for the years between 1988 and 2004. Anthropogenic land cover changes were quantified by screen digitising polygons from three false colour composite images over this period to determine the area of forested land that had been cleared and the area that had been affected by mine-derived sediment transported by the Ajkwa River system. The results show that both settlement and sediment had radically altered land cover and together had led to a sixfold increase in the area of ultra-diverse lowland tropical rainforest cleared in the study area. The study highlights the utility of this method to monitor elements of the impact of large-scale mining and other extensive forms of resource exploitation such as deforestation in developing countries

A robust automated technique for operational calibration of ceilometers using the integrated backscatter from totally attenuating liquid clouds

A simple and robust method for calibrating ceilometers has been tested in an operational environment demonstrating that the calibrations are stable to better than ± 5 % over a period of a year. The method relies on using the integrated backscatter (B) from liquid clouds that totally extinguish the ceilometer signal; B is inversely proportional to the lidar ratio (S) of the backscatter to the extinction for cloud droplets. The calibration technique involves scaling the observed backscatter so that B matches the predicted value for S of 18.8 ± 0.8 sr for cloud droplets, at ceilometer wavelengths. For accurate calibration, care must be taken to exclude any profiles having targets with different values of S, such as drizzle drops and aerosol particles, profiles that do not totally extinguish the ceilometer signal, profiles with low cloud bases that saturate the receiver, and any profiles where the window transmission or the lidar pulse energy is low. A range dependent multiple scattering correction that depends on the ceilometer optics should be applied to the profile. A simple correction for water vapour attenuation for ceilometers operating at around 910 nm wavelength is applied to the signal using the vapour profiles from a forecast analysis. For a generic ceilometer in the UK the 90-day running mean of the calibration coefficient over a period of 20 months is constant to within 3 % with no detectable annual cycle, thus confirming the validity of the humidity and multiple scattering correction. For Gibraltar, where cloud cover is less prevalent than in the UK, the 90-day running mean calibration coefficient was constant to within 4 %. The more sensitive ceilometer model operating at 1064 nm is unaffected by water vapour attenuation but is more prone to saturation in liquid clouds. We show that reliable calibration is still possible, provided the clouds used are above a certain altitude. The threshold is instrument dependent but is typically around 2 km. We also identify a characteristic signature of saturation, and remove any profiles with this signature. Despite the more restricted sample of cloud profiles, a robust calibration is readily achieved, and, in the UK, the running mean 90-day calibration coefficients varied by about 4 % over a period of one year. The consistency of profiles observed by nine pairs of co-located ceilometers in the UK Met Office network operating at around 910 nm and 1064 nm provided independent validation of the calibration technique. EUMETNET is currently networking 700 European ceilometers so they can provide ceilometer profiles in near real time to European weather forecast centres and has adopted the cloud calibration technique described in this paper for ceilometers with a wavelength of around 910 nm

Seabed AUV Offers New Platform for High-Resolution Imaging

A number of marine biological, geological, and archaeological applications share the need for high-resolution optical and acoustic imaging of the sea floor [Ballard et al., 2002; Greene et al., 2000; Shank et al., 2002]. In particular,there is a compelling need to conduct studies in depths beyond those considered reasonable for divers (∼50 m) down to depths at the shelf edge and continental slope (∼1000–2000 m). Some of the constraints associated with such work include the requirement to work off of small coastal vessels or fishing boats of opportunity,and the requirement for the vehicle components to be air-shippable to enable inexpensive deployments at far-flung oceanographic sites of interest

Minocycline 200 mg or 400 mg versus placebo for mild Alzheimer's disease: the MADE Phase II, three-arm RCT

Background: Minocycline is an anti-inflammatory drug and protects against the toxic effects of β-amyloid in vitro and in animal models of Alzheimer’s disease. To the best of our knowledge, no randomised placebo-controlled clinical trials in patients with Alzheimer’s disease looking at the efficacy and tolerability of minocycline have been carried out. Objectives: The trial investigated whether or not minocycline was superior to placebo in slowing down the rate of decline in cognitive and functional ability over 2 years. The safety and tolerability of minocycline were also assessed. Design: A Phase II, three-arm, randomised, double-blind, multicentre trial with a semifactorial design. Participants continued on trial treatment for up to 24 months. Setting: Patients were identified from memory services, both within the 32 participating NHS trusts and within the network of memory services supported by the Dementias and Neurodegenerative Diseases Research Network (also known as DeNDRoN). Participants: Patients with standardised Mini Mental State Examination scores of > 23 points and with Alzheimer’s disease assessed by the National Institute on Aging–Alzheimer’s Association’s criteria were identified from memory services. Intervention: Patients with mild Alzheimer’s disease were randomly allocated 1 : 1 : 1 to receive one of three treatments: arm 1 – 400 mg per day of minocycline; arm 2 – 200 mg per day of minocycline; or arm 3 – placebo. Patients continued treatment for 24 months. Participants, investigators and outcome assessors were blind to treatment allocation. Main outcome measures: Primary outcome measures were decline in standardised Mini Mental State Examination and Bristol Activities of Daily Living Scale scores of combined minocycline treatment arms versus placebo, as analysed by intention-to-treat repeated measures regression. Results: Between 23 May 2014 and 14 April 2016, 554 participants were randomised. Of the 544 eligible participants, the mean age was 74.3 years and the average standardised Mini Mental State Examination score was 26.4 points. A total of 252 serious adverse events were reported, with the most common categories being neuropsychiatric and cardiocirculatory. Significantly fewer participants completed treatment with 400 mg of minocycline [29% (53/184)] than 200 mg [62% (112/181)] or placebo [64% (114/179)] (p < 0.0001), mainly because of gastrointestinal symptoms (p = 0.0008), dermatological side effects (p = 0.02) and dizziness (p = 0.01). Assessment rates were also lower in the 400-mg treatment arm: 68% (119 of 174 expected) for standardised Mini Mental State Examination scores at 24 months, compared with 82% (144/176) for the 200-mg treatment arm and 84% (140/167) for the placebo arm. Decline in standardised Mini Mental State Examination scores over the 24-month study period in the combined minocycline arms was similar to that in the placebo arm (4.1- vs. 4.3-point reduction; p = 0.9), as was the decline in the 400- and 200-mg treatment arms (3.3 vs. 4.7 points; p = 0.08). Likewise, worsening of Bristol Activities of Daily Living Scale scores over 24 months was similar in all trial arms (5.7, 6.6 and 6.2 points in the 400-mg treatment arm, 200-mg treatment arm and placebo arm, respectively; a p-value of 0.57 for minocycline vs. placebo and a p-value of 0.77 for 400 vs. 200 mg of minocycline). Results were similar in different patient subgroups and in sensitivity analyses adjusting for missing data. Limitations: Potential limitations of the study include that biomarkers were not used to confirm the diagnosis of Alzheimer’s disease, as these and apolipoprotein E (APOE) genotyping are not routinely available within the NHS. Compliance was also worse than expected and differential follow-up rates were observed, with fewer assessments obtained for the 400-mg treatment arm than for the 200-mg treatment and placebo arms. Conclusions: Minocycline does not delay the progress of cognitive or functional impairment in people with mild Alzheimer’s disease over a 2-year period. Minocycline at a dose of 400 mg is poorly tolerated in this population. Future work: The Minocycline in mild Alzheimer’s DiseasE (MADE) study provides a framework for a streamlined trial design that can be usefully applied to test other disease-modifying therapies

Cost-effectiveness analyses for mirtazapine and sertraline in dementia: randomised controlled trial

BACKGROUND Depression is a common and costly comorbidity in dementia. There are very few data on the cost-effectiveness of antidepressants for depression in dementia and their effects on carer outcomes. AIMS To evaluate the cost-effectiveness of sertraline and mirtazapine compared with placebo for depression in dementia. METHOD A pragmatic, multicentre, randomised placebo-controlled trial with a parallel cost-effectiveness analysis (trial registration: ISRCTN88882979 and EudraCT 2006-000105-38). The primary cost-effectiveness analysis compared differences in treatment costs for patients receiving sertraline, mirtazapine or placebo with differences in effectiveness measured by the primary outcome, total Cornell Scale for Depression in Dementia (CSDD) score, over two time periods: 0-13 weeks and 0-39 weeks. The secondary evaluation was a cost-utility analysis using quality-adjusted life years (QALYs) computed from the Euro-Qual (EQ-5D) and societal weights over those same periods. RESULTS There were 339 participants randomised and 326 with costs data (111 placebo, 107 sertraline, 108 mirtazapine). For the primary outcome, decrease in depression, mirtazapine and sertraline were not cost-effective compared with placebo. However, examining secondary outcomes, the time spent by unpaid carers caring for participants in the mirtazapine group was almost half that for patients receiving placebo (6.74 v. 12.27 hours per week) or sertraline (6.74 v. 12.32 hours per week). Informal care costs over 39 weeks were £1510 and £1522 less for the mirtazapine group compared with placebo and sertraline respectively. CONCLUSIONS In terms of reducing depression, mirtazapine and sertraline were not cost-effective for treating depression in dementia. However, mirtazapine does appear likely to have been cost-effective if costing includes the impact on unpaid carers and with quality of life included in the outcome. Unpaid (family) carer costs were lower with mirtazapine than sertraline or placebo. This may have been mediated via the putative ability of mirtazapine to ameliorate sleep disturbances and anxiety. Given the priority and the potential value of supporting family carers of people with dementia, further research is warranted to investigate the potential of mirtazapine to help with behavioural and psychological symptoms in dementia and in supporting carers