It's all about data movement: Optimising FPGA data access to boost performance

The use of reconfigurable computing, and FPGAs in particular, to accelerate computational kernels has the potential to be of great benefit to scientific codes and the HPC community in general. However, whilst recent advanced in FPGA tooling have made the physical act of programming reconfigurable architectures much more accessible, in order to gain good performance the entire algorithm must be rethought and recast in a dataflow style. Reducing the cost of data movement for all computing devices is critically important, and in this paper we explore the most appropriate techniques for FPGAs. We do this by describing the optimisation of an existing FPGA implementation of an atmospheric model's advection scheme. By taking an FPGA code that was over four times slower than running on the CPU, mainly due to data movement overhead, we describe the profiling and optimisation strategies adopted to significantly reduce the runtime and bring the performance of our FPGA kernels to a much more practical level for real-world use. The result of this work is a set of techniques, steps, and lessons learnt that we have found significantly improves the performance of FPGA based HPC codes and that others can adopt in their own codes to achieve similar results.Comment: Preprint of article in 2019 IEEE/ACM International Workshop on Heterogeneous High-performance Reconfigurable Computing (H2RC

Feeling the heat: Elevated temperature affects male display activity of a lekking grassland bird

Most climate-species models relate range margins to long-term mean climate variables but lack mechanistic understanding of the ecological or demographic processes underlying the climate response. We examined the case of a climatically limited edge-of-range population of a medium-sized grassland bird, for which climate responses may involve a behavioural trade-off between temperature stress and reproduction. We hypothesised that temperature will be a limiting factor for the conspicuous, male snort-call display behaviour, and high temperatures would reduce the display activity of male birds. Using remote tracking technology with tri-axial accelerometers we classified and studied the display behaviour of 17 free-ranging male little bustards at 5 sites in the Iberian Peninsula. Display behaviour was related to temperature using two classes of Generalized Additive Mixed Models (GAMMs) at different temporal resolutions. GAMMs showed that temperature, time of the day and Julian date explained variation in display behaviour within the day, with birds snort-calling significantly less during higher temperatures. We also showed that variation in daily snort-call activity was related to average daytime temperatures, with our model predicting an average decrease in daytime snort-call display activity of up to 10.9% for the temperature increases projected by 2100 in this region due to global warming. For little bustards and more widely in lekking grassland birds, reduced display behaviour could impact inter- and intra-sex mating behaviour interactions through sexual selection and mate choice mechanisms, with possible consequences on mating and reproductive success of this species. The study provides a reproducible example for how accelerometer data can be used to answer research questions with important conservation inferences related to the impacts of climate change on a range of taxonomic groups

Feeling the heat: Elevated temperature affects male display activity of a lekking grassland bird

Most climate-species models relate range margins to long-term mean climate variables but lack mechanistic understanding of the ecological or demographic processes underlying the climate response. We examined the case of a climatically limited edge-of-range population of a medium-sized grassland bird, for which climate responses may involve a behavioural trade-off between temperature stress and reproduction. We hypothesised that temperature will be a limiting factor for the conspicuous, male snort-call display behaviour, and high temperatures would reduce the display activity of male birds. Using remote tracking technology with tri-axial accelerometers we classified and studied the display behaviour of 17 free-ranging male little bustards at 5 sites in the Iberian Peninsula. Display behaviour was related to temperature using two classes of Generalized Additive Mixed Models (GAMMs) at different temporal resolutions. GAMMs showed that temperature, time of the day and Julian date explained variation in display behaviour within the day, with birds snort-calling significantly less during higher temperatures. We also showed that variation in daily snort-call activity was related to average daytime temperatures, with our model predicting an average decrease in daytime snort-call display activity of up to 10.9% for the temperature increases projected by 2100 in this region due to global warming. For little bustards and more widely in lekking grassland birds, reduced display behaviour could impact inter- and intra-sex mating behaviour interactions through sexual selection and mate choice mechanisms, with possible consequences on mating and reproductive success of this species. The study provides a reproducible example for how accelerometer data can be used to answer research questions with important conservation inferences related to the impacts of climate change on a range of taxonomic groups

Position, swimming direction and group size of fin whales (Balaenoptera physalus) in the presence of a fast-ferry in the Bay of Biscay

We analyze group size, swimming direction and the orientation of fin whales relative to a fast ferry in the Bay of Biscay. Fin whale groups (≥3 individuals) were on average closer to the vessel than single individuals and pairs (F1,114 = 4.94, p = 0.028) and were more often observed within a high-risk angle ahead of the ferry (binomial probability: p = 7.60 × 10−11). Also, small groups tend to swim in the opposite direction (heading of 180°) of the ferry at the starboard side (binomial test: p = 6.86 × 10−5) and at the portside (binomial test: p = 0.0156). These findings provide valuable information to improve shipping management procedures in areas at high risk for collisions

The importance of multimorbidity in explaining utilisation and costs across health and social care settings : evidence from South Somerset’s Symphony Project

Since the inception of the NHS, an ever-present challenge has been to improve integration of care within the health care system and with social care. Many people have complex and ongoing care needs and require support from multiple agencies and various professionals. But care is often fragmented and uncoordinated, with no one agency taking overall responsibility, so it is often left to individuals and their families to negotiate the system as best they can. South Somerset’s Symphony is designed to establish greater collaboration between primary, community, acute and social care, particularly for people with complex conditions

Land Surface Temperature from Ka-band (37 GHZ) Passive Microwave Observations

An alternative to thermal infrared satellite sensors for measuring land surface temperature (T<inf>s</inf>) is presented. The 37 GHz vertical polarized brightness temperature is used to derive T<inf>s</inf> because it is considered the most appropriate microwave frequency for temperature retrieval. This channel balances a reduced sensitivity to soil surface characteristics with a relatively high atmospheric transmissivity. It is shown that with a simple linear relationship, accurate values for T<inf>s</inf> can be obtained from this frequency, with a theoretical bias of within 1 K for 70% of vegetated land areas of the globe. Barren, sparsely vegetated, and open shrublands cannot be accurately described with this single channel approach because variable surface conditions become important. The precision of the retrieved land surface temperature is expected to be better than 2.5 K for forests and 3.5 K for low vegetation. This method can be used to complement existing infrared derived temperature products, especially during clouded conditions. With several microwave radiometers currently in orbit, this method can be used to observe the diurnal temperature cycles with surprising accuracy. © 2009 by the American Geophysical Union

The future of evapotranspiration : global requirements for ecosystem functioning, carbon and climate feedbacks, agricultural management, and water resources

The fate of the terrestrial biosphere is highly uncertain given recent and projected changes in climate. This is especially acute for impacts associated with changes in drought frequency and intensity on the distribution and timing of water availability. The development of effective adaptation strategies for these emerging threats to food and water security are compromised by limitations in our understanding of how natural and managed ecosystems are responding to changing hydrological and climatological regimes. This information gap is exacerbated by insufficient monitoring capabilities from local to global scales. Here, we describe how evapotranspiration (ET) represents the key variable in linking ecosystem functioning, carbon and climate feedbacks, agricultural management, and water resources, and highlight both the outstanding science and applications questions and the actions, especially from a space-based perspective, necessary to advance them