Statistical data correction for unreliable memories

In this paper, we introduce a statistical data-correction framework that aims at improving the DSP system performance in presence of unreliable memories. The proposed signal processing framework implements best-effort error mitigation for signals that are corrupted by defects in unreliable storage arrays using a statistical correction function extracted from the signal statistics, a data-corruption model, and an application-specific cost function. An application example to communication systems demonstrates the efficacy of the proposed approach.

Refresh-free dynamic standard-cell based memories: Application to a QC-LDPC decoder

The area and power consumption of low-density parity check (LDPC) decoders are typically dominated by embedded memories. To alleviate such high memory costs, this paper exploits the fact that all internal memories of a LDPC decoder are frequently updated with new data. These unique memory access statistics are taken advantage of by replacing all static standard-cell based memories (SCMs) of a prior-art LDPC decoder implementation by dynamic SCMs (D-SCMs), which are designed to retain data just long enough to guarantee reliable operation. The use of D-SCMs leads to a 44% reduction in silicon area of the LDPC decoder compared to the use of static SCMs. The low-power LDPC decoder architecture with refresh-free D-SCMs was implemented in a 90nm CMOS process, and silicon measurements show full functionality and an information bit throughput of up to 600 Mbps (as required by the IEEE 802.11n standard).

On the performance of LDPC and turbo decoder architectures with unreliable memories

In this paper, we investigate the impact of faulty memory bit-cells on the performance of LDPC and Turbo channel decoders based on realistic memory failure models. Our study investigates the inherent error resilience of such codes to potential memory faults affecting the decoding process. We develop two mitigation mechanisms that reduce the impact of memory faults rather than correcting every single error. We show how protection of only few bit-cells is sufficient to deal with high defect rates. In addition, we show how the use of repair-iterations specifically helps mitigating the impact of faults that occur inside the decoder itself.

Mitigating the Impact of Faults in Unreliable Memories for Error-Resilient Applications

Inherently error-resilient applications in areas such as signal processing, machine learning and data analytics provide opportunities for relaxing reliability requirements, and thereby reducing the overhead incurred by conventional error correction schemes. In this paper, we exploit the tolerable imprecision of such applications by designing an energy-efficient fault-mitigation scheme for unreliable data memories to meet target yield. The proposed approach uses a bit-shuffling mechanism to isolate faults into bit locations with lower significance. This skews the bit-error distribution towards the low order bits, substantially limiting the output error magnitude. By controlling the granularity of the shuffling, the proposed technique enables trading-off quality for power, area, and timing overhead. Compared to error-correction codes, this can reduce the overhead by as much as 83% in read power, 77% in read access time, and 89% in area, when applied to various data mining applications in 28nm process technology.

Queering Memories of the Troubles: Performing LGBTQ testimonies in Northern Ireland

In Northern Ireland, decades of religious and political unrest led to the marginalization not only of rights but also the experiences and voices of those who identify as Lesbian, Gay, Bisexual, Trans and/or Queer (LGBTQ). The peace process has arguably created space in which sexual minorities can voice their experiences and articulate counter-memories to those that tend to dominate ethno-nationalist commemorations of the conflict. This essay explores two productions of Northern Ireland’s first publicly funded gay theatre company, TheatreofplucK, led by artistic director Niall Rea: D.R.A.G (Divided, Radical and Gorgeous) was first performed in 2011 and explores the personal experiences of a Belfast drag queen in the form of personal testimonial monologue. The forthcoming (November 2015) performed archive installation, Tr<uble, by Shannon Yee, assembles true-life testimonies of the LGBTQ community in Northern Ireland during and after the Troubles. I will explore how performed and performative memories have the potential to ‘queer’ remembrance of the Troubles.

Remembering forwards: or how to live together in the future with divided memories

Memory is thought to be about the past. The past is a problem in conflict transformation. This lecture suggests memory can also be about the future. It introduces the notion of remembering forwards, which is contrasted with remembering backwards. The distinction between these two forms of remembering defines the burden of memory in post-conflict societies generally and specifically in Ireland. In societies emerging out of conflict, where divided memories in part constituted the conflict, social memory privileges remembering backward. Collective and personal memories elide within social memory to perpetuate divided group identities and contested personal narratives. Above all, social memory works to arbitrate the future, by predisposing an extreme memory culture that locks people into the past. Forgetting the past is impossible and undesirable. What is needed in societies emerging out of conflict is to be released from the hold that oppressive and haunting memories have over people. This lecture will suggest that this is found in the idea of remembering forwards. This is not the same as forgetting. It is remembering to cease to remember oppressive and haunting memories. It does not involve non-remembrance but active remembering: remembering to cease to remember the past. While the past lives in us always, remembering forwards assists us in not living in the past. Remembering forwards thus allows us to live in tolerance in the future despite the reality that divided memories endure and live on. The lecture further argues that these enduring divided memories need to be reimagined by the application of truth, tolerance, togetherness and trajectory. The lecture suggests that it is through remembering forwards with truth, tolerance, togetherness and trajectory that people in post-conflict societies can inherit the future despite their divided pasts and live in tolerance in the midst of contested memories.

Remembering, imagining, false memories & personal meanings

The Self-Memory System encompasses the working self, autobiographical memory and episodic memory. Specific autobiographical memories are patterns of activation over knowledge structures in autobiographical and episodic memory brought about by the activating effect of cues. The working self can elaborate cues based on the knowledge they initially activate and so control the construction of memories of the past and the future. It is proposed that such construction takes place in the remembering–imagining system – a window of highly accessible recent memories and simulations of near future events. How this malfunctions in various disorders is considered as are the implication of what we term the modern view of human memory for notions of memory accuracy. We show how all memories are to some degree false and that the main role of memories lies in generating personal meanings.

Brief memories of Niagara : its rapids, falls, and whirlpool /

On cover and spine: Memories of Niagara.

The Role of Sleep in the Selective Reconsolidation of Declarative Memories

While sleep has been shown to be involved in memory consolidation and the selective enhancement of newly acquired memories of future relevance (Wilhelm, et al., 2011), limited research has investigated the role of sleep or future relevance in processes of memory reconsolidation. The current research employed a list-method directed forgetting procedure in which participants learned two lists of syllable pairs on Night 1 and received directed forgetting instructions on Night 2. On Night 2, one group (Labile; n = 15) received a memory reactivation treatment consisting of reminders designed to return memories of the learned lists to a labile state. A second group (Stable, n = 16) received similar reminders designed to leave memories of the learned lists in their stable state. No differences in forgetting were found across the two lists or groups. However, a negative correlation between frontal delta (1 – 4 Hz) electroencephalographic (EEG) power during Early Stage 2 non-rapid eye movement (NREM) sleep and forgetting of to-beremembered material was found exclusively in the Labile group (r = -.61, p < .05). Further, central theta (4 – 8 Hz ) EEG power during rapid eye movement (REM) sleep was found to correlate with directed forgetting exclusively in the Labile group (r = .81, p < .001) and total forgetting in the Stable group (r = .50, p < .05). These observed relationships support the proposed hypothesis suggesting that sleep processes are involved in the reconsolidation of labile memories, and that this reconsolidation may be selective for memories of future relevance. A role for sleep in the beneficial reprocessing of memories through the selective reconsolidation of labile memories in NREM sleep and the weakening of memories in REM sleep is discussed.

Memories sur l'agriculture, les instrumens aratoires et d'economie rurale

UANL

The role of ‘Shared Memories’ in shaping nationalist movements : a comparative historical analysis of the Flemish and Québécois nationalist movements

Les mouvements nationalistes flamands et québécois divergent en concernant leur structure; par exemple le nationalisme flamand s'est développé comme un mouvement chrétien-démocrate, alors que le nationalisme québécois contemporain s’est galvanisé autour d'une idéologie laïque de gauche. Par ailleurs, il existe un contraste entre les poids sociodémographique, politique et économique portés par la région de Flandres en Belgique, et ceux portés dans la province du Québec au Canada. Cependant, malgré les influences divergentes structurelles et systémiques, les mouvements nationalistes flamand et québécois ont développé et maintenu des profils très similaires. Par exemple, les deux mouvements nationalistes se définissent par une distinction ethnolinguistique, les deux ont un discours nationaliste parallèle axé sur la nécessité de préserver et de protéger la langue et la culture de la communauté nationale, et les deux se concentrent sur l'obtention d'une redistribution des pouvoirs culturels et politiques. Dans ce mémoire, nous proposons que le profil nationaliste ressemblant du mouvement nationaliste flamand et québécois puisse être expliqué par le développement d'un « nationalisme ethnolinguistique de contestation », qui était initialement mis en place par les nationalistes flamands et québécois cherchant à corriger les effets d'une « division culturelle du travail ». Ce sentiment d’un nationalisme de contestation ethnolinguistique est instrumentalisé et perpétué par les nationalistes flamands et québécois en évoquant certains « souvenirs partagés », qui sont trouvés dans le récit historique de la communauté nationale. Ces souvenirs partagés, ainsi que leurs représentations symboliques, reflètent les sentiments de protestation, injustice et victimisation, qui sont vitaux pour les nationalistes flamands et québécois dans le maintien de leur expression parallèlement à un nationalisme de contestation ethnolinguistique en Flandres et au Québec.

Nanocrystalline Ge Flash Memories: Electrical Characterization and Trap Engineering

Conventional floating gate non-volatile memories (NVMs) present critical issues for device scalability beyond the sub-90 nm node, such as gate length and tunnel oxide thickness reduction. Nanocrystalline germanium (nc-Ge) quantum dot flash memories are fully CMOS compatible technology based on discrete isolated charge storage nodules which have the potential of pushing further the scalability of conventional NVMs. Quantum dot memories offer lower operating voltages as compared to conventional floating-gate (FG) Flash memories due to thinner tunnel dielectrics which allow higher tunneling probabilities. The isolated charge nodules suppress charge loss through lateral paths, thereby achieving a superior charge retention time. Despite the considerable amount of efforts devoted to the study of nanocrystal Flash memories, the charge storage mechanism remains obscure. Interfacial defects of the nanocrystals seem to play a role in charge storage in recent studies, although storage in the nanocrystal conduction band by quantum confinement has been reported earlier. In this work, a single transistor memory structure with threshold voltage shift, Vth, exceeding ~1.5 V corresponding to interface charge trapping in nc-Ge, operating at 0.96 MV/cm, is presented. The trapping effect is eliminated when nc-Ge is synthesized in forming gas thus excluding the possibility of quantum confinement and Coulomb blockade effects. Through discharging kinetics, the model of deep level trap charge storage is confirmed. The trap energy level is dependent on the matrix which confines the nc-Ge.