Precision analysis for hardware acceleration of numerical algorithms

The precision used in an algorithm affects the error and performance of individual computations, the memory usage, and the potential parallelism for a fixed hardware budget. However, when migrating an algorithm onto hardware, the potential improvements that can be obtained by tuning the precision throughout an algorithm to meet a range or error specification are often overlooked; the major reason is that it is hard to choose a number system which can guarantee any such specification can be met. Instead, the problem is mitigated by opting to use IEEE standard double precision arithmetic so as to be ‘no worse’ than a software implementation. However, the flexibility in the number representation is one of the key factors that can be exploited on reconfigurable hardware such as FPGAs, and hence ignoring this potential significantly limits the performance achievable. In order to optimise the performance of hardware reliably, we require a method that can tractably calculate tight bounds for the error or range of any variable within an algorithm, but currently only a handful of methods to calculate such bounds exist, and these either sacrifice tightness or tractability, whilst simulation-based methods cannot guarantee the given error estimate. This thesis presents a new method to calculate these bounds, taking into account both input ranges and finite precision effects, which we show to be, in general, tighter in comparison to existing methods; this in turn can be used to tune the hardware to the algorithm specifications. We demonstrate the use of this software to optimise hardware for various algorithms to accelerate the solution of a system of linear equations, which forms the basis of many problems in engineering and science, and show that significant performance gains can be obtained by using this new approach in conjunction with more traditional hardware optimisations

The effect of water-soluble carbohydrate concentration and type on in vitro rumen methane output of perennial ryegrass determined using a 24-hour batch-culture gas production technique

peer-reviewedThe objective of this study was to examine the effects of water-soluble carbohydrate (WSC) concentration and type on the in vitro rumen methane (CH4) output of perennial ryegrass (PR) using a 24-hour batch-culture gas production technique. Dried and milled PR was incubated either alone (PR-O) or with added sucrose (PR-S), inulin (PR-I), or sucrose plus inulin (PR-S+I; sucrose:inulin ratio of 1:4) in sealed glass bottles [0.5 g total substrate dry matter (DM) per bottle] at 39 °C for 24 hours with buffered rumen fluid. The WSC types were added (except for PR-O) so that the WSC concentration in each fermentation bottle at the start of the incubation was either 180 (i.e., PR-O), 225, 270, 315, or 360 g/kg of total substrate DM incubated. There were linear decreases in CH4 output per gram of DM disappeared (CH4/ivDMD) and per mmol of total volatile fatty acid output (CH4/tVFA) with increasing WSC concentration in the incubated substrate. The WSC type had no effect on in vitro rumen CH4 output. It is concluded that since CH4/ivDMD and CH4/tVFA were reduced by increasing the concentration of WSC incubated with PR, it would be worthwhile to undertake in vivo experiments to examine these effects on in vivo CH4 emissions per unit of animal product.Funding for this study was provided under the National Development Plan through the Research Stimulus Fund administered by the Department of Agriculture, Food & the Marine (RSF no. 07 517)

Curriculum development for nursing and assistive technology

This paper addresses the issue of curriculum innovation and development for nursing education and the inclusion of assistive technology as a subject for student nurses. The paper examines the nurses’ role as part of the interdisciplinary team in creating awareness and ensuring that people with disabilities are the focus of the assistive technology process. Nurses have the greatest contact with users of healthcare services, and are therefore in a key position to ensure that assistive technology contributes to addressing their needs. Curriculum development is the point of growth for all educational activities and a curriculum is the offering of socially valued knowledge, attitude or skill, made available to students during formal education. Contemporary nurse education needs to be relevant and flexible with curricula that will address the present and future health and social care needs of society. In Ireland nurse education has moved from a hospital to a university based programme and assistive technology has been included as an optional module in the nursing degree programme in Dublin City University

Design and Evaluation of a Probabilistic Music Projection Interface

We describe the design and evaluation of a probabilistic interface for music exploration and casual playlist generation. Predicted subjective features, such as mood and genre, inferred from low-level audio features create a 34- dimensional feature space. We use a nonlinear dimensionality reduction algorithm to create 2D music maps of tracks, and augment these with visualisations of probabilistic mappings of selected features and their uncertainty. We evaluated the system in a longitudinal trial in users’ homes over several weeks. Users said they had fun with the interface and liked the casual nature of the playlist generation. Users preferred to generate playlists from a local neighbourhood of the map, rather than from a trajectory, using neighbourhood selection more than three times more often than path selection. Probabilistic highlighting of subjective features led to more focused exploration in mouse activity logs, and 6 of 8 users said they preferred the probabilistic highlighting mode

Phase response reconstruction for non-minimum phase systems using frequency-domain magnitude values

It is often more complicated to measure the phase response of a large system than the magnitude. In that case, one can attempt to use the Kramers-Kronig (KK) relations for magnitude and phase, which relates magnitude and phase analytically. The advantage is that then only the magnitude of the frequency response needs to be measured. We show that the KK relations for magnitude and phase may yield invalid results when the transfer function has zeros located in the right half of the complex s-plane, i.e. the system is non-minimum phase. In this paper we propose a method which enables to determine these zeros, by using specific excitation signals and measuring the resulting time responses of the system. The method is verified using blind tests among the authors. When the locations of the zeros in the right half of the complex s-plane are known, modified KK relations can be successfully applied to non-minimum phase systems. We demonstrate this by computing the phase response of the electric field, excited by a point dipole source inside a closed cavity with Perfect Electrically Conducting (PEC) walls. Also, the effects of simulated measurement noise are considered for this example.Comment: This is a preprint version of the final publicatio

Centreless governance for the management of a global R&D process: Public-Private Partnerships and Plant-Genetic Resource Management

Public-private partnership is one new model of centreless or networked governance that has emerged in recent years. This article examines the development and use of partnerships in the management and funding of public pulse breeding programs. The paper evaluates the theory of innovation and knowledge management and uses case study and social network analysis to examine the nature and strength of the international public pulse breeding system and analyzes in detail the three major national public pulse breeding systems in Australia, the US and Canada. Australia appears to have the most developed system of public-private partnerships, centred on the Grains Research Development Corporation and, CLIMA. Canada lacks a centralized national body such as the GRDC, but possesses a regional system centred on a university research centre (the Crop Development Centre) and a hybrid organization (the Saskatchewan Pulse Growers). The US is remarkable for the lack of any significant public-private partnerships in public pulse breeding