A First Step Towards Cost Functions for Quantum-dot Cellular Automata Designs

Quantum-dot cellular automata (QCA) is potentially a very attractive alternative to CMOS for future digital designs. Circuit designs in QCA have been extensively studied. However, how to properly evaluate the QCA circuits has not been carefully considered. To date, metrics and area-delay cost functions directly mapped from CMOS technology have been used to compare QCA designs, which is inappropriate due to the differences between these two technologies. In this paper, several cost metrics specifically aimed at QCA circuits are studied. It is found that delay, the number of QCA logic gates, and the number and type of crossovers, are important metrics that should be considered when comparing QCA designs. A family of new cost functions for QCA circuits is proposed. As fundamental components in QCA computing arithmetic, QCA adders are reviewed and evaluated with the proposed cost functions. By taking the new cost metrics into account, previous best adders become unattractive and it has been shown that different optimization goals lead to different “best” adders.

The first major step in the peace process’? Exploring the impact of the Anglo-Irish Agreement on Irish Republican thinking

This article supports interpretations of the Anglo-Irish Agreement of 1985 as a significant factor contributing to the development of the Northern Ireland peace process. However, it also emphasises a certain serendipity in the Agreement's effect on northern nationalist, and more specifically republican, politics in the region. In particular, it stresses that a specific interpretation of the Agreement promoted by the Social Democratic and Labour Party inspired a dialogue with republicanism, encouraging an ongoing reappraisal within the latter about the nature of Britain's role in Northern Ireland. This, the article argues, reinforced the movement towards a more political approach that republicans had begun in the 1980s, and encouraged their eventual embrace of a constitutional strategy in the 1990s. However, in advancing this argument, the article notes that such an outcome was far from the minds of the British and Irish officials who negotiated the Anglo-Irish Agreement. The Agreement was intended to marginalise rather than accommodate republicans. Despite this, it provided an inadvertent incentive to draw militant republicanism into the democratic process in Northern Ireland.

The first major step in the peace process’? Exploring the impact of the Anglo-Irish Agreement on Irish republican thinking

This article supports interpretations of the Anglo-Irish Agreement of 1985 as a significant factor contributing towards the development of the Northern Ireland peace process. However, it also emphasises a certain serendipity in the Agreement’s effect on northern nationalist, and more specifically republican, politics in the region. In particular, it stresses that a specific interpretation of the Agreement promoted by the SDLP inspired a dialogue with republicanism, encouraging an ongoing re-appraisal within the latter about the nature of Britain’s role in Northern Ireland. This, the article argues, reinforced the movement towards a more political approach that republicans had begun in the 1980s, and encouraged their eventual embrace of a constitutional strategy in the 1990s. However, in advancing this argument, the article notes that such an outcome was far from the minds of the British and Irish officials who negotiated the Anglo-Irish Agreement. The Agreement was intended to marginalise rather than accommodate republicans. Despite this, it provided an inadvertent incentive to draw militant republicanism into the democratic process in Northern Ireland.

Step by step: reconstruction of terrestrial animal movement paths by dead-reckoning

BACKGROUND: Research on wild animal ecology is increasingly employing GPS telemetry in order to determine animal movement. However, GPS systems record position intermittently, providing no information on latent position or track tortuosity. High frequency GPS have high power requirements, which necessitates large batteries (often effectively precluding their use on small animals) or reduced deployment duration. Dead-reckoning is an alternative approach which has the potential to 'fill in the gaps' between less resolute forms of telemetry without incurring the power costs. However, although this method has been used in aquatic environments, no explicit demonstration of terrestrial dead-reckoning has been presented.

RESULTS: We perform a simple validation experiment to assess the rate of error accumulation in terrestrial dead-reckoning. In addition, examples of successful implementation of dead-reckoning are given using data from the domestic dog Canus lupus, horse Equus ferus, cow Bos taurus and wild badger Meles meles.

CONCLUSIONS: This study documents how terrestrial dead-reckoning can be undertaken, describing derivation of heading from tri-axial accelerometer and tri-axial magnetometer data, correction for hard and soft iron distortions on the magnetometer output, and presenting a novel correction procedure to marry dead-reckoned paths to ground-truthed positions. This study is the first explicit demonstration of terrestrial dead-reckoning, which provides a workable method of deriving the paths of animals on a step-by-step scale. The wider implications of this method for the understanding of animal movement ecology are discussed.

Is it time for standards and a common data exchange format for digital image analysis?

Digital image analysis is at a crossroads. While the technology has made great strides over the past few decades, there is an urgent need for image analysis to inform the next wave of large scale tissue biomarker discovery studies in cancer. Drawing parallels from the growth of next generation sequencing, this presentation will consider the case for a common language or standard format for storing and communicating digital image analysis data. In this context, image analysis data comprises more than simply an image with markups and attached key-value pair metrics. The desire to objectively benchmark competing platforms or a push for data to be deposited to public repositories much like genomics data may drive the need for a standard that also encompasses granular, cell-by-cell data.