A new look at dual-hop relaying: Performance limits with hardware impairments

Physical transceivers have hardware impairments that create distortions which degrade the performance of communication systems. The vast majority of technical contributions in the area of relaying neglect hardware impairments and, thus, assume ideal hardware. Such approximations make sense in low-rate systems, but can lead to very misleading results when analyzing future high-rate systems. This paper quantifies the impact of hardware impairments on dual-hop relaying, for both amplify-and-forward and decode-and-forward protocols. The outage probability (OP) in these practical scenarios is a function of the effective end-to-end signal-to-noise-and-distortion ratio (SNDR). This paper derives new closed-form expressions for the exact and asymptotic OPs, accounting for hardware impairments at the source, relay, and destination. A similar analysis for the ergodic capacity is also pursued, resulting in new upper bounds. We assume that both hops are subject to independent but non-identically distributed Nakagami-m fading. This paper validates that the performance loss is small at low rates, but otherwise can be very substantial. In particular, it is proved that for high signal-to-noise ratio (SNR), the end-to-end SNDR converges to a deterministic constant, coined the SNDR ceiling, which is inversely proportional to the level of impairments. This stands in contrast to the ideal hardware case in which the end-to-end SNDR grows without bound in the high-SNR regime. Finally, we provide fundamental design guidelines for selecting hardware that satisfies the requirements of a practical relaying system.

K-Contagion: Sound, Space and Speed in Psy's 'Gangnam Style'

Park Jae-Sang’s (otherwise known as PSY) bewilderingly successful pop contagion ‘Gangnam Style’ needs no introduction. As of January 2013, it has become the most watched video in YouTube’s history and has garnered over 1.23 billion hits since. ‘Gangnam Style’ has also become a rapid global pop phenomenon with multiple parodic reproductions, imitations and adaptations; Rapper PSY himself has become an international name and styled as the ‘anti-hero’ of the glamour-driven K-pop scene. His fame has transcended the social sphere and permeated the political stratosphere with politicians such as Barrack Obama and David Cameron being among the many whom PSY has exchanged pleasantries with. Apart from breaking ground and creating social and media history in many ways, ‘Gangnam Style’ has even been purported by UN Secretary-General Ban Ki Moon to be a “force for world peace” – cultural barriers are demolished as the world dances. Underlying this sentiment is the video’s almost universal appeal that assumes a supracultural yet equally paradoxical translatability: Korea’s neoteric ‘K-Wave’ phenomenon is at once local yet global, and where the latter is predicated on the former quality. The paper’s concern is thus two-fold. It will consider the dromological aspects of this musical contagion as it exemplifies and performs quite literally Paul Virilio’s thesis that the modern condition is driven by speed yet arrested to a dictatorship of movement. While many theories have been put forward for this astounding pop peculiarity, this paper would also examine the intercultural currents that advocate such a global (pop) cultural response. Through an analysis of sonic qualities – digital techno-beat rhythms, synth-based musicality, cyclical lyrics, horse-galloping movements – and acoustic receptions, it will consider the simultaneous and dichotomous currents of glocalisation and globalisation as it relates to the ways in which sonic ‘hyper-links’ establish new concepts of global-cultural identities even as these seem to be interrogated in the borderless worlds of hyper-mediatised realities and cultural technologies.

Speed of processing in the primary motor cortex: A continuous theta burst stimulation study

‘Temporally urgent’ reactions are extremely rapid, spatially precise movements that are evoked following discrete stimuli. The involvement of primary motor cortex (M1) and its relationship to stimulus intensity in such reactions is not well understood. Continuous theta burst stimulation (cTBS) suppresses focal regions of the cortex and can assess the involvement of motor cortex in speed of processing. The primary objective of this study was to explore the involvement of M1 in speed of processing with respect to stimulus intensity. Thirteen healthy young adults participated in this experiment. Behavioral testing consisted of a simple button press using the index finger following median nerve stimulation of the opposite limb, at either high or low stimulus intensity. Reaction time was measured by the onset of electromyographic activity from the first dorsal interosseous (FDI) muscle of each limb. Participants completed a 30 min bout of behavioral testing prior to, and 15 min following, the delivery of cTBS to the motor cortical representation of the right FDI. The effect of cTBS on motor cortex was measured by recording the average of 30 motor evoked potentials (MEPs) just prior to, and 5 min following, cTBS. Paired t-tests revealed that, of thirteen participants, five demonstrated a significant attenuation, three demonstrated a significant facilitation and five demonstrated no significant change in MEP amplitude following cTBS. Of the group that demonstrated attenuated MEPs, there was a biologically significant interaction between stimulus intensity and effect of cTBS on reaction time and amplitude of muscle activation. This study demonstrates the variability of potential outcomes associated with the use of cTBS and further study on the mechanisms that underscore the methodology is required. Importantly, changes in motor cortical excitability may be an important determinant of speed of processing following high intensity stimulation.

Inhuman and Degrading Punishment, Dignity, and the Limits of Retribution

The recent judgment of the Grand Chamber of the European Court of Human Rights (ECtHR) in Vinter and others v United Kingdom provides a much needed clarification of the parameters of the prohibition on inhuman and degrading punishment under Article 3 of the European Convention on Human Rights (ECHR) as it applies to whole life orders of imprisonment under mandatory life sentences – essentially, life imprisonment without parole. The Grand Chamber’s judgment refines Strasbourg doctrine on life imprisonment and the prospect of release and illuminates key principles concerning inhuman and degrading punishment under Article 3 of the ECHR. This article considers the judgment’s profound significance in relation to both human rights and penology.

Travelling without moving? Limits of European governance for Romani inclusion

The European Union's commitment to citizen participation in policymaking and implementation reflects a wider concern for securing Europe's ‘unity in diversity’. However, across its member-states, individuals belonging to the diverse linguistic, ethnic and social groups often referred to as ‘Roma’ find themselves excluded from political, social and economic participation in countries where they live. The past decade saw the appearance of a more concerted approach to improve the participation of individuals belonging to these groups in social and economic processes. This article examines what it refers to as the European Governance for Romani inclusion (EGRI), assessing policy steps undertaken at the European institutional level towards Romani inclusion and the tools for policy implementation. The paper concludes that the EGRI has offered only limited opportunities for the marginalised Roma to redress their exclusion.

Voltage scalable high-speed robust hybrid arithmetic units using adaptive clocking

In this paper, we explore various arithmetic units for possible use in high-speed, high-yield ALUs operated at scaled supply voltage with adaptive clock stretching. We demonstrate that careful logic optimization of the existing arithmetic units (to create hybrid units) indeed make them further amenable to supply voltage scaling. Such hybrid units result from mixing right amount of fast arithmetic into the slower ones. Simulations on different hybrid adder and multipliers in BPTM 70 nm technology show 18%-50% improvements in power compared to standard adders with only 2%-8% increase in die-area at iso-yield. These optimized datapath units can be used to construct voltage scalable robust ALUs that can operate at high clock frequency with minimal performance degradation due to occasional clock stretching. © 2009 IEEE.

High-Speed Fully Homomorphic Encryption Over the Integers

A fully homomorphic encryption (FHE) scheme is envisioned as a key cryptographic tool in building a secure and reliable cloud computing environment, as it allows arbitrary evaluation of a ciphertext without revealing the plaintext. However, existing FHE implementations remain impractical due to very high time and resource costs. To the authors’ knowledge, this paper presents the first hardware implementation of a full encryption primitive for FHE over the integers using FPGA technology. A large-integer multiplier architecture utilising Integer-FFT multiplication is proposed, and a large-integer Barrett modular reduction module is designed incorporating the proposed multiplier. The encryption primitive used in the integer-based FHE scheme is designed employing the proposed multiplier and modular reduction modules. The designs are verified using the Xilinx Virtex-7 FPGA platform. Experimental results show that a speed improvement factor of up to 44 is achievable for the hardware implementation of the FHE encryption scheme when compared to its corresponding software implementation. Moreover, performance analysis shows further speed improvements of the integer-based FHE encryption primitives may still be possible, for example through further optimisations or by targeting an ASIC platform.

The Limits of Local Accommodation: Why Contentious Events Remain Prone to Conflict in Northern Ireland

This article examines the difficulties of finding local solutions to the problem of contentious events in contemporary Northern Ireland. In so doing, it offers a sociological perspective on fundamental divisions in Northern Ireland: between classes and between communities. It shows how its chosen case study—parades and associated protests in north Belfast—exemplifies the most fundamental problem that endures in post-Agreement Northern Ireland, namely that political authority is not derived from a common civic culture (as is the norm in Western liberal democracy) but rather that legitimacy is still founded on the basis of the culture of either one or the other community. Haugaard’s reflections on authority and legitimacy are used to explore Northern Ireland’s atypical experience of political conflict vis-`a-vis the Western liberal democratic model. The Bourdieusian concepts of field illusio and doxa help to explain why it is that parading remains such an important political and symbolic touchstone in this society.

Getting Away With It:Corruption, Moral Indignation and the Limits of Legal Accountability

In this paper we address the idea of ‘legal but corrupt’ through a discussion of two cases: abuse scandals in the Irish Catholic Church and the financial services industry in the wake of the Global Financial Crisis. We identify two important dynamics that generated the scandals: that they were driven by strong and stable groups existing within a peculiar kind of ‘accountability space’ that we describe as ‘monastic’ and that those groups persisted with tacit or explicit support from the state. ‘Legal but corrupt’ is, we argue, a matter of insider incomprehension sustained by the ceding of sovereignty over some aspect of social or economic life.

Limits of Dissent, Perils of Activism: Spaces of Resistance and the New Security Logic

On 26 December 2003 an Israeli activist was shot by the Israeli Army while he was participating in a demonstration organized by Anarchists Against the Wall (AAtW) in the West Bank. This was the first time Israeli Soldiers have deliberately shot live bullets at a Jewish-Israeli activist. This paper is an attempt to understand the set of conditions, the enveloping frameworks, and the new discourses that have made this event, and similar shootings that soon followed, possible. Situating the actions of AAtW within a much wider context of securitization—of identities, movements, and bodies—we examine strategies of resistance which are deployed in highly securitized public spaces. We claim that an unexpected matrix of identity in which abnormality is configured as security threat render the bodies of activists especially precarious. The paper thus provides an account of the new rationales of security technologies and tactics which increasingly govern public spaces.

High-speed conversion of xylose to l-lactate by electrodialysis bioprocess

Conversion of xylose to l-lactate was carried out by Lactococcus lactis IO-1 using an electrodialysis bioprocess (ED-BP). At 50 g l -1 xylose, the ED-BP was already complete in half the time (32 h) taken by the control culture without electrodialysis (>60 h). At 80 g l -1 xylose, the control culture was unable to consume >50 g l -1 xylose, whereas the ED-BP consumed 75 g l -1 xylose in 45 h. Thus, the simultaneous removal of lactate and acetate by ED-BP was associated with high-speed l-lactate production, increased xylose consumption and an increased l-lactate production. Copyright (C) 1998 Elsevier Science B.V.