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1
Adeney, Allyson Louise. "Broken Assemblages: the connections between memory, hope and brokenness." Thesis, The University of Sydney, 2021. https://hdl.handle.net/2123/25891.
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This thesis examines the connections between memory, brokenness and hope by investigating philosophical thought models, critically analysing artworks and exploring personal perspectives. It questions whether material aesthetics, spatial sensitivities and sculptural sympathies can offer insights into repairing and restoring unhopeful thought patterns after personal brokenness. The accompanying artworks, Now and Still, are perpetual artefacts verifying hopeful healing while remaining places of enduring hope.
My research examines rhizomatic thought as described by Giles Deleuze and Felix Guattari, alongside the theories of Rosalind Krauss concerning shared material characteristics to investigate possible applications to human memory. I explored brokenness and hope through researching the historical repair techniques of Kintsugi and Sashiko before drawing on examples of repair in the natural and spiritual world. Sarah Sze’s Triple Point, Joseph Kosuth’s One and Three Chairs and Yayoi Kusama’s Armchair (Accumulation) are visual supports that illustrate how humans can activate memory towards hope by activating human agency.
The paper includes discussions concerning the tendency in scientific research to see the brain as an isolated organ, detached from the human being’s ontology, and potential avenues of repair, namely hopeful renewal. Further, the research investigates the possibility of reconfiguring memories into alternate hopeful thought assemblages by sculpting memories, treating them as an artist would a medium.
The emphasis of the research was on reassembling broken memory assemblages that needed hopeful repair. It includes an analysis of pieces by contemporary artists Junki Oki and Charlotte Bailey and references contemporary environmental works by Rachel Sussman and Janet Laurence.
The accompanying artworks, Now and Still show distinct yet integrated assemblages that capture the adaptive and recursive nature of memory, hope, and brokenness.
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Merchant, Sean Robert. "Tending the Broken Window." The Ohio State University, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=osu1493285369498883.
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Rushworth, S. J. "Aspects of immediate memory for non-meaningful patterned sequences." Thesis, University of Reading, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.370818.
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Drever, Johannes. "Rapid acquisition of long spatial sequences in long-term memory." Diss., lmu, 2012. http://nbn-resolving.de/urn:nbn:de:bvb:19-150231.
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Alm, Kylie H. "Hippocampal Representations of Targeted Memory Reactivation and Reactivated Temporal Sequences." Diss., Temple University Libraries, 2017. http://cdm16002.contentdm.oclc.org/cdm/ref/collection/p245801coll10/id/422606.
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Psychology<br>Ph.D.<br>Why are some memories easy to retrieve, while others are more difficult to access? Here, we tested whether we could bias memory replay, a process whereby newly learned information is reinforced by reinstating the neuronal patterns of activation that were present during learning, towards particular memory traces. The goal of this biasing is to strengthen some memory traces, making them more easily retrieved. To test this, participants were scanned during interleaved periods of encoding and rest. Throughout the encoding runs, participants learned triplets of images that were paired with semantically related sound cues. During two of the three rest periods, novel, irrelevant sounds were played. During one critical rest period, however, the sound cues learned in the preceding encoding period were played in an effort to preferentially increase reactivation of the associated visual images, a manipulation known as targeted memory reactivation. Representational similarity analyses were used to compare multi-voxel patterns of hippocampal activation across encoding and rest periods. Our index of reactivation was selectively enhanced for memory traces that were targeted for preferential reactivation during offline rest, both compared to information that was not targeted for preferential reactivation and compared to a baseline rest period. Importantly, this neural effect of targeted reactivation was related to the difference in delayed order memory for information that was cued versus uncued, suggesting that preferential replay may be a mechanism by which specific memory traces can be selectively strengthened for enhanced subsequent memory retrieval. We also found partial evidence of discrimination of unique temporal sequences within the hippocampus. Over time, multi-voxel patterns associated with a given triplet sequence became more dissimilar to the patterns associated with the other sequences. Furthermore, this neural marker of sequence preservation was correlated with the difference in delayed order memory for cued versus uncued triplets, signifying that the ability to reactivate particular temporal sequences within the hippocampus may be related to enhanced temporal order memory for the cued information. Taken together, these findings support the claim that awake replay can be biased towards preferential reactivation of particular memory traces and also suggest that this preferential reactivation, as well as representations of reactivated temporal sequences, can be detected within patterns of hippocampal activation.<br>Temple University--Theses
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Williamson, Victoria Jane. "Comparing short-term memory for sequences of verbal and tonal materials." Thesis, University of York, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.550492.
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A long standing debate surrounds the issue of whether there is overlap in the cognitive processing of language and music. This thesis examined the extent to which there are similarities in the immediate serial recall (ISR) of verbal and tonal pitch sequences using the working memory model as the empirical framework. The thesis had three aims. The first was to develop an ISR task that would allow individuals of any level of musical training to report back sequences of tones and letters. The second aim was to compare letter and tone sequence recall performance under various conditions known to affect ISR for auditory-verbal materials. The third aim was to examine performance as a function of musical expertise. Nine experiments were conducted in total. The first six experiments tested, refined and validated the new ISR tone paradigm. The final three experiments compared musicians and nonmusicians letter and tone sequence recall using manipulations known to affect ISR for auditory-verbal items; phonological similarity (pitch proximity used for tone recall), articulatory suppression and irrelevant sound. Similarities across the results included comparable sequence length effects for letter and tone conditions, an effect of pitch proximity and phonological similarity for nonmusicians, and effects of articulatory suppression on recall of both sequence types for both groups. However, there were also a number of differences in tone recall compared to letter recall including a lack of recency and no effect of irrelevant sound. Therefore, a complete theoretical overlap between language and music processing in short-term memory was not supported by the evidence. The problems of equivalent testing across the language and music domain, and across populations of varying musical expertise were discussed. It was suggested that increased understanding of how cognitive resources are shared to process language and music in the brain would come from future research combining behavioural experiments with functional models and neuroimaging studies.
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Bagnall, Imogen. "Afrofuturism and Generational Trauma in N. K. Jemisin‘s Broken Earth Trilogy." Thesis, Stockholms universitet, Engelska institutionen, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-194870.
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N. K. Jemisin‘s Broken Earth Trilogy explores the methods and effects of systemic oppression. Orogenes are historically oppressed and dehumanised by the wider society of The Stillness. In this thesis, I will be exploring the ways in which trauma experienced by orogenes is repeated through generations, as presented through Essun‘s varied and complex relationships with her children, and with the Fulcrum Guardian Schaffa. The collective trauma of orogenes is perpetuated through different direct and indirect actions in a repetitive cycle, on societal, interpersonal and familial levels. My reading will be in conversation with theories of trauma literature and cultural trauma, and will be informed by Afrofuturist cultural theory. Although science fiction and fantasy encourage the imagination, worldbuilding is inherently influenced by lived experiences. It could thus be stated that the trauma experienced by orogenes is informed by the collective trauma of African-Americans, as experienced by N. K. Jemisin. Afrofuturism is an aesthetic mode and critical lens which prioritises the imagining of a liberated future. Writing science fiction and fantasy through an Afrofuturist aesthetic mode encourages authors to explore forms of collective trauma as well as methods of healing. Jemisin creates an explicit parallel between the traumatic African-American experience and that of orogenes. Afrofuturist art disrupts linear time and addresses past and present trauma through the imagining of the future. The Broken Earth Trilogy provides a blueprint for the imagined liberation of oppressed groups. Using Afrofuturist tropes such as technology, the ―Black Genius‖ figure and alienation, Jemisin demonstrates the power of reclamation and the possibility of a self-created future for oppressed groups.
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Cei, Anne. "Hippocampal cell assembly sequences in rats : neurophysiological mechanims and role in memory." Paris 6, 2013. http://www.theses.fr/2013PA066618.
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The hippocampus is a brain structure that plays a critical role in spatial and episodic memory. In rats, hippocampal cells called "place cells" fire specifically when the animal is at a particular location of the environment. Remarkably, when a rat traverses a path, the place cells fire in sequence in a very short time scale compatible with the "synaptic plasticity" processes between cells that might provide the formation of a memory trace reflecting the trajectory performed by the rat. Compatible with this hypothesis, the same sequences of cells are reactivated spontaneously during sleep (as if the rat "dreamed" of its environment) especially during transient hippocampal activity patterns called Sharp Wave- Ripples (SPW-R). These reactivations could then underlie the consolidation of the memory traces acquired during wakefulness. The purpose of this thesis is to better understand the formation and the consolidation role and mechanisms of hippocampal cell sequences. First, to study the dynamic of sequence emergence, we test the effect of an atypical backward movement of the rats using an electric model train. Our results show that during backwards movement, the same place cells than during forward movement are activated but their order in the sequence is reversed and this is not due to the activity of the entorhinal cortex input signal that encodes the direction of the head of the animal. These observations challenge the theoretical framework built around the emergence of sequences and favors the hypothesis that the hippocampus dynamically and internally adapts its activity to the experience of the animal. In a second step, we are interested in the impact of learning on sequence reactivations during SPW-Rs. Our results show that the suppression of SPW- Rs induces an increase in the number of SPW-Rs or homeostatic rebound specifically after a learning task (and not after a simple exploration). This rebound is canceled by the injection of an antagonist of the NMDA receptors known to play a role in synaptic plasticity processes. Homostatic regulation would thus be directly controlled by the establishment of memory traces during learning so that this ensures their consolidation during sleep<br>L'hippocampe est une structure cérébrale qui joue un rôle critique dans la mémoire épisodique et la mémoire spatiale. Chez le rat, des cellules hippocampiques appelées « cellules de lieu » déchargent spécifiquement lorsque l'animal se trouve à un endroit donné de l'environnement. De façon caractéristique, lorsqu'un rat parcourt une trajectoire, les cellules de lieu déchargent en séquence à une échelle de temps très courte compatible avec des processus de « plasticité synaptique » entre les cellules. Cette compression temporelle pourraient ainsi permettre la formation d'une trace mnésique de la trajectoire effectuée par le rat. Compatible avec cette hypothèse, les mêmes séquences de cellules sont réactivées de façon spontanée pendant le sommeil (comme si le rat « rêvait » de son environnement) notamment lors de patterns d'activité hippocampique transitoires appelés Sharp-Wave-Ripples (SPW-R). Ces réactivations pourraient alors sous-tendre la consolidation des traces mnésiques acquises pendant l'éveil durant le sommeil. Le but de ce travail de thèse est de mieux comprendre le rôle et les mécanismes de formation et de consolidation des séquences de cellules hippocampiques. Dans un premier temps, pour étudier la dynamique de mise en place des séquences, nous avons tester l'effet d'un déplacement atypique des rats en marche arrière à l'aide d'un train électrique. Nos résultats montrent que dans cette condition les même cellules de lieu qu'en marche avant sont activées mais leur ordre dans la séquence s'inverse et ceci n'est pas du à l'activité des signaux d'entrées du cortex entorhinal codant la direction de la tête de l'animal. Ces observations remettent en cause le cadre théorique établie autour de l'émergence des séquences et favorise l'hypothèse que l'hippocampe adapte son activité dynamiquement, et de façon interne selon l'expérience de l'animal. Dans un second temps, nous nous sommes intéressés à l'impact des processus d'apprentissage sur la réactivations des séquences pendant les SPW-Rs. Nos résultats montrent que la suppression des SPW-Rs spécifiquement après une tâche d'apprentissage (et pas suite à une simple exploration) induit une augmentation du nombre de SPW-Rs ou rebond homéostatique. Ce rebond est annulé par l'injection d'un antagoniste des récepteurs NMDA connus pour jouer un rôle dans les processus de plasticité synaptiques. Ce phénomène de régulation serait donc directement contrôlé par la mise en place des traces mnésiques pendant l'apprentissage et aurait pour but d'assurer leur consolidation pendant le sommeil
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Harris, Philip G., and n/a. "Cortical activity associated with rhythmic grouping of pitch sequences." Swinburne University of Technology, 2007. http://adt.lib.swin.edu.au./public/adt-VSWT20071001.113258.
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Segmentational grouping in music listening refers to the organisation of individual tones
into tone groups that tend to be processed and subsequently recalled as perceptual units
or chunks. Grouping of tones via this process tends to occur at natural breaks in
structure of a tone sequence, so that relatively larger changes in pitch, amplitude or
timing are perceived as boundaries which cue the segmentational grouping process.
Segmentational grouping processes have been examined using behavioural research
techniques; yet neurophysiological processes underlying the grouping process have
received little attention, and are poorly understood. This study aimed to identify brain
regions involved in the segmentational grouping process as cued by rhythmic
information. Participants performed two auditory tasks while brain electrical activity
responses were monitored using Steady-State Probe Topography (SSPT).
Behavioural responses evoked in a task probing individuals' use of lengthened-duration
tones to organise memory for pitch sequences indicated that longer-duration tones were
used as cues to organise working memory representations of the musical patterns.
Examination of dynamic SSPT responses during the encoding phase of a probe
recognition task indicated that greater use of rhythmic cues to organise working
memory representations was associated with activation of a network of left hemisphere
frontal, temporal and parietal regions. During the lengthened tone, activation of left
central and vertex regions and progressive activation of left temporal and
temporoparietal regions were linked with use of the deviant status of the lengthened
tone to update temporal expectations for the sequence. Excitatory responses observed in
left posterior frontal and temporal regions to a tone following the lengthened tone were
proposed to reflect temporal allocation of attention to this point in time, whereas
sustained excitatory activation of left temporal, and temporoparietal regions reflected
the role of these regions in supporting representations of the tone events in working
memory. Finally, late inhibitory responses to the tone following the lengthened tone in
left frontal, temporal, temporoparietal, and parietal regions were linked with the
manipulation and closure of the working memory trace in association with the grouping
process. Together, these findings support the activation of a network of left frontal,
temporal and parietal regions underlying rhythmic grouping of pitch sequences.
10
Scott, Anne Grete. "Monkeys, movements, and memories: Behavioral sequences and short-term memory in aged monkeys." Diss., The University of Arizona, 1990. http://hdl.handle.net/10150/185189.
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Six young and six old squirrel monkeys were tested on two different short-term memory tasks. One was a two-choice problem, the other a nine-choice problem. A baseline, or one-choice, problem was also included. A video camera recorded all behaviors displayed by the monkeys during testing. Behaviors coded were turning, aggression, displacement, exploratory, huddling, orienting, locomotion, screen activities, and visual scanning. Also recorded was correct or incorrect choice and whether the animal showed evidence of seeing the cue stimulus. Old animals committed more errors during both phases of the experiment. Older animals were also more likely to engage in active behaviors, such as turning, whereas young animals were more likely to manifest less active behaviors, such as visual scanning and orienting. Young animals were also more likely to see the stimulus. A path analytic procedure was used to determine direct effects of age on performance and indirect effects mediated through behaviors manifested prior to the choice. For the two-choice problem, approximately half of the age effects on performance were attributable to indirect effects. For the nine-choice problem almost three quarters of the age effects on performance were attributable to indirect effects. These findings indicate that age differences in short-term memory performance are not direct effects of age alone. The age effect also occurs because age affects the behaviors of the monkeys and that these behaviors have a large effect on subsequent memory performance.
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Harris, Philip Geoffrey. "Cortical activity associated with rhythmic grouping of pitch sequences." Australasian Digital Thesis Program, 2007. http://adt.lib.swin.edu.au/public/adt-VSWT20071001.113258/index.html.
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Thesis (PhD) - Swinburne University of Technology, Brain Sciences Institute, 2007.<br>A thesis for Doctorate of Philosophy, Brain Sciences Institute, Swinburne University of Technology - 2007. Typescript. Bibliography: p. 245-285.
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Drever, Johannes [Verfasser], and Andreas [Akademischer Betreuer] Straube. "Rapid acquisition of long spatial sequences in long-term memory / Johannes Drever. Betreuer: Andreas Straube." München : Universitätsbibliothek der Ludwig-Maximilians-Universität, 2012. http://d-nb.info/1028922094/34.
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Montgomery, Nicole Votolato. "Temporal sequence effects a memory framework /." Columbus, Ohio : Ohio State University, 2007. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1179322348.
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Muraleedharan, Nair Jayakrishnan. "Signature Verification Model: A Long Term Memory Approach." Ohio University / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1427210243.
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Pechey, A. M. "Some effects of input and output modes of representation on memory for sequences of meaningfully related events." Thesis, University of Cambridge, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.355027.
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Drieu, Céline. "Neurophysiological bases of memory formation and consolidation : contents and dynamics of hippocampal cell assembly sequences in rats." Thesis, Paris 6, 2017. http://www.theses.fr/2017PA066486.
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A la fin des années 50, les premières descriptions d'amnésie antérograde chez le patient H.M. ont mis en évidence le rôle crucial de l'hippocampe dans la mémoire. Ces travaux fondateurs ont été étendus grâce à l'enregistrement de l'activité cérébrale chez le rat libre de ses mouvements, avec l'étonnante découverte que les neurones hippocampiques codent la position de l'animal dans l'environnement (« cellules de lieu »). Lorsqu'un rat parcourt une trajectoire, il traverse successivement différents « champs de lieu », et les cellules de lieu correspondantes déchargent les unes après les autres en séquences. De façon surprenante, lorsque la décharge d'une cellule de lieu est observée par rapport au rythme thêta (~8 Hz) présent dans l'hippocampe lorsque le rat explore son environnement, l'ordre dans lequel les cellules déchargent est maintenu à une échelle de temps très rapide (~150 ms), au sein de chaque cycle de l'oscillation thêta. Ces « séquences thêta » reflètent ainsi les positions passée, présente et future de l'animal, ancrant les lieux visités par l'animal dans leur contexte temporel. Pendant le sommeil, les séquences d'activité des cellules hippocampiques sont spontanément réactivées, reproduisant virtuellement la trajectoire du rat lors de son exploration. Ces réactivations ont lieu lors de patterns d'activité transitoires appelés sharp wave-ripples (SPW-Rs). La réintégration répétitive de l'activité séquentielle liée à l'expérience pourrait renforcer les connexions synaptiques entre les cellules. De plus, il a été montré que les SWR-Rs et leurs réactivations associées jouent un rôle causal dans la consolidation de la mémoire. Comment ces réactivations peuvent-elles avoir lieu ? De façon intéressante, pendant l'exploration, les séquences thêta permettent la compression des trajectoires de l'animal à une échelle de temps compatible avec des processus de plasticité. Par conséquent, ces séquences thêta pourraient soutenir l'apprentissage séquentiel pendant l'exploration, et pourraient sous-tendre le codage initial des traces mnésiques. Toutefois, des preuves directes en faveur de ce scénario n'ont pas été fournies<br>In the late 50's, the first descriptions of anterograde amnesia in patient H.M. have highlighted the crucial role of the hippocampus in memory. These seminal works have been extended with brain electrophysiological recordings in freely moving rats, with the striking discovery that hippocampal neurons code for the location of the animal in the environment (‘place cells'). When a rat runs through a trajectory, it successively crosses multiple ‘place fields', and the corresponding place cells fire one after the other in sequence, in an order corresponding to the trajectory of the rat. Strikingly, when the place cell firing is observed relative to the ongoing theta rhythm (~8 Hz) recorded in the hippocampus when the rats is exploring its environment, the order in which the cells fire is maintained at a much shorter time scale (~150 ms), in each cycle of the theta oscillations. These ‘theta sequences' thus reflects the past, present and future locations of the animal, anchoring locations in their temporal context. During subsequent sleep, the sequences of hippocampal cell activity are spontaneously reactivated, virtually reproducing the trajectory of the rat during its previous exploration. This replay occurs during transient hippocampal activity patterns called sharp wave-ripples (SPW-Rs). Repetitive reinstatement of experience-related sequential activity may strengthen synaptic connections between cells. Moreover, SPW-Rs and their associated replay have been causally linked to memory consolidation. How does such replay occur during sleep? Interestingly, during exploration, theta sequences allowed the temporal compression of the animal’s trajectory at a time-scale compatible with synaptic plasticity processes. Therefore, these theta sequences have been hypothetized to support sequential structure learning during exploration, and might underlie the initial encoding of memory traces. However, direct evidence supporting this scenario remains elusive
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Albert, Simon. "Development of a fast DRAM analyzer and measurement of typical and critical memory access sequences in applications." München Verl. Dr. Hut, 2008. http://d-nb.info/992163323/04.
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Gönner, Lorenz, Julien Vitay, and Fred Hamker. "Predictive Place-Cell Sequences for Goal-Finding Emerge from Goal Memory and the Cognitive Map: A Computational Model." Universitätsbibliothek Chemnitz, 2017. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-qucosa-230378.
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Hippocampal place-cell sequences observed during awake immobility often represent previous experience, suggesting a role in memory processes. However, recent reports of goals being overrepresented in sequential activity suggest a role in short-term planning, although a detailed understanding of the origins of hippocampal sequential activity and of its functional role is still lacking. In particular, it is unknown which mechanism could support efficient planning by generating place-cell sequences biased toward known goal locations, in an adaptive and constructive fashion. To address these questions, we propose a model of spatial learning and sequence generation as interdependent processes, integrating cortical contextual coding, synaptic plasticity and neuromodulatory mechanisms into a map-based approach. Following goal learning, sequential activity emerges from continuous attractor network dynamics biased by goal memory inputs. We apply Bayesian decoding on the resulting spike trains, allowing a direct comparison with experimental data. Simulations show that this model (1) explains the generation of never-experienced sequence trajectories in familiar environments, without requiring virtual self-motion signals, (2) accounts for the bias in place-cell sequences toward goal locations, (3) highlights their utility in flexible route planning, and (4) provides specific testable predictions.
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Teo, Sui-Guan. "Analysis of nonlinear sequences and streamciphers." Thesis, Queensland University of Technology, 2013. https://eprints.qut.edu.au/63358/1/Sui-Guan_Teo_Thesis.pdf.
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Streamciphers are common cryptographic algorithms used to protect the confidentiality of frame-based communications like mobile phone conversations and Internet traffic. Streamciphers are ideal cryptographic algorithms to encrypt these types of traffic as they have the potential to encrypt them quickly and securely, and have low error propagation.
The main objective of this thesis is to determine whether structural features of keystream generators affect the security provided by stream ciphers.These structural features pertain to the state-update and output functions used in keystream generators. Using linear sequences as keystream to encrypt messages is known to be insecure. Modern keystream generators use nonlinear sequences as keystream.The nonlinearity can be introduced through a keystream generator's state-update function, output function, or both.
The first contribution of this thesis relates to nonlinear sequences produced by the well-known Trivium stream cipher. Trivium is one of the stream ciphers selected in a final portfolio resulting from a multi-year project in Europe called the ecrypt project. Trivium's structural simplicity makes it a popular cipher to cryptanalyse, but to date, there are no attacks in the public literature which are faster than exhaustive keysearch. Algebraic analyses are performed on the Trivium stream cipher, which uses a nonlinear state-update and linear output function to produce keystream. Two algebraic investigations are performed: an examination of the sliding property in the initialisation process and algebraic analyses of Trivium-like streamciphers using a combination of the algebraic techniques previously applied separately by Berbain et al. and Raddum. For certain iterations of Trivium's state-update function, we examine the sets of slid pairs, looking particularly to form chains of slid pairs. No chains exist for a small number of iterations.This has implications for the period of keystreams produced by Trivium.
Secondly, using our combination of the methods of Berbain et al. and Raddum, we analysed Trivium-like ciphers and improved on previous on previous analysis with regards to forming systems of equations on these ciphers. Using these new systems of equations, we were able to successfully recover the initial state of Bivium-A.The attack complexity for Bivium-B and Trivium were, however, worse than exhaustive keysearch. We also show that the selection of stages which are used as input to the output function and the size of registers which are used in the construction of the system of equations affect the success of the attack.
The second contribution of this thesis is the examination of state convergence. State convergence is an undesirable characteristic in keystream generators for stream ciphers, as it implies that the effective session key size of the stream cipher is smaller than the designers intended. We identify methods which can be used to detect state convergence. As a case study, theMixer streamcipher, which uses nonlinear state-update and output functions to produce keystream, is analysed. Mixer is found to suffer from state convergence as the state-update function used in its initialisation process is not one-to-one. A discussion of several other streamciphers which are known to suffer from state convergence is given. From our analysis of these stream ciphers, three mechanisms which can cause state convergence are identified.The effect state convergence can have on stream cipher cryptanalysis is examined. We show that state convergence can have a positive effect if the goal of the attacker is to recover the initial state of the keystream generator.
The third contribution of this thesis is the examination of the distributions of bit patterns in the sequences produced by nonlinear filter generators (NLFGs) and linearly filtered nonlinear feedback shift registers. We show that the selection of stages used as input to a keystream generator's output function can affect the distribution of bit patterns in sequences produced by these keystreamgenerators, and that the effect differs for nonlinear filter generators and linearly filtered nonlinear feedback shift registers. In the case of NLFGs, the keystream sequences produced when the output functions take inputs from consecutive register stages are less uniform than sequences produced by NLFGs whose output functions take inputs from unevenly spaced register stages. The opposite is true for keystream sequences produced by linearly filtered nonlinear feedback shift registers.
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Albert, Simon [Verfasser]. "Development of a fast DRAM analyzer and measurement of typical and critical memory access sequences in applications / Simon Albert." München : Verl. Dr. Hut, 2008. http://d-nb.info/999941690/34.
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Chenkov, Nikolay. "Network mechanisms underlying sharp wave ripples and memory replay." Doctoral thesis, Humboldt-Universität zu Berlin, 2017. http://dx.doi.org/10.18452/18491.
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Komplexe Muster neuronaler Aktivität entstehen während der Sharp-wave Ripples
(SWRs) im Hippocampus und während der Up States im Neokortex (Zuständen mit
hoher Aktivität). Sequenzen von Verhalten, die in der Vergangenheit erlebt
wurden, werden während des komplexen Musters abgespielt. Die zugrunde liegenden
Mechanismen sind nicht gründlich erforscht: Wie können kleine synaptische
Veränderungen die großflächige Netzwerkaktivität während des Gedächtnisabrufes
und der Gedächtniskonsolidierung kontrollieren?
Im ersten Teil dieser Abhandlung wird die Hypothese aufgestellt, dass eine schwache
synaptische Konnektivität zwischen Hebbschen Assemblies von der bereits
vorhandenen rekurrenten Konnektivität gefördert wird. Diese Hypothese wird auf
folgende Weise geprüft: die vorwärts gekoppelten Assembly-Sequenzen werden
in neuronale Netzwerke eingebettet, mit einem Gleichgewicht zwischen
exzitatorischer und inhibitorischer Aktivität. Simulationen und analytische
Berechnungen haben gezeigt, dass rekurrente Verbindungen innerhalb der
Assemblies zu einer schnelleren Signalverstärkung führen, was eine Reduktion
der notwendigen Verbindungen zwischen den Assemblies zur Folge hat. Diese
Aktivität kann entweder von kleinen sensorisch ähnlichen Inputs hervorgerufen
werden oder entsteht spontan infolge von Aktivitätsschwankungen. Globale --
möglicherweise neuromodulatorische -- Änderungen der neuronalen Erregbarkeit
können daher die Netzwerkzustände steuern, die Gedächnisabruf und die
Konsolidierung begünstigen.
Der zweite Teil der Arbeit geht der Herkunft der SWRs nach, die in vitro
beobachtet wurden. Neueste Studien haben gezeigt, dass SWR-ähnliche
Erscheinungen durch optogenetische Stimulation der Subpopulationen von
inhibitorischen Neuronen hervorgerufen werden können (Schlingloff et al.,
2014). Um diese Ergebnisse zu erklären wird ein de-inhibierendes
Schaltkreis-Modell diskutiert, das die beobachteten Populationsausbrüche
generieren kann. Die Auswirkungen der pharmakologischen GABAergischen
Modulatoren auf die SWR-Häufigkeit werden in vitro untersucht. Die gewonnenen
Ergebnisse wurden in Rahmen des Schaltkreis-Modells analysiert. Insbesondere
wird den folgenden Fragen nachgegangen: Wie unterdrückt Gabazine, ein
GABA_A-Rezeptor-Antagonist, die Entwicklung von SWRs? Wird das Zeitintervall
zwischen SWRs durch die Dynamik der GABA_B Rezeptoren moduliert?<br>Complex patterns of neural activity appear during up-states in the neocortex
and sharp-wave ripples (SWRs) in the hippocampus, including sequences that
resemble those during prior behavioral experience. The mechanisms underlying
this replay are not well understood. How can small synaptic footprints engraved
by experience control large-scale network activity during memory retrieval and
consolidation?
In the first part of this thesis, I hypothesise that sparse and weak
synaptic connectivity between Hebbian assemblies are boosted by pre-existing
recurrent connectivity within them. To investigate this idea, sequences of
assemblies connected in a feedforward manner are embedded in random neural
networks with a balance of excitation and inhibition. Simulations and
analytical calculations show that recurrent connections within assemblies allow
for a fast amplification of signals that indeed reduces the required number of
inter-assembly connections. Replay can be evoked by small sensory-like cues or
emerge spontaneously by activity fluctuations. Global--potentially
neuromodulatory--alterations of neuronal excitability can switch between
network states that favor retrieval and consolidation.
The second part of this thesis investigates the origin of the SWRs observed in
in-vitro models. Recent studies have demonstrated that SWR-like events can be
evoked after optogenetic stimulation of subpopulations of inhibitory neurons
(Schlingloff et al., 2014; Kohus et al., 2016). To explain these results, a
3-population model is discussed as a hypothetical disinhibitory circuit that
could generate the observed population bursts. The effects of pharmacological
GABAergic modulators on the SWR incidence in vitro are analysed. The results
are discussed in the light of the proposed disinhibitory circuit. In
particular, how does gabazine, a GABA_A receptor antagonist, suppress the
generation of SWRs? Another explored question is whether the slow dynamics of
GABA_B receptors is modulating the time scale of the inter-event intervals.
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Hyde, Robert A. "Mnemonic Representations of Transient Stimuli and Temporal Sequences in the Rodent Dentate Gyrus In Vitro." Case Western Reserve University School of Graduate Studies / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=case1352773632.
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Tejero-Cantero, Álvaro [Verfasser], and Christian [Akademischer Betreuer] Leibold. "Of memories and ripples : functional and mechanistic aspects of memory sequences during hippocampal ripples / Álvaro Tejero-Cantero. Betreuer: Christian Leibold." München : Universitätsbibliothek der Ludwig-Maximilians-Universität, 2012. http://d-nb.info/1029662797/34.
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Kaulicke, Peter. "Space and Time in the Formative Period: Some Final Reflections." Pontificia Universidad Católica del Perú, 2012. http://repositorio.pucp.edu.pe/index/handle/123456789/113584.
Full textAbstract:
These final reflections stress the relevance of this substantial collection of papers presented in both volumes of the Boletín. Monumental architecture is particularly important with early beginnings, long construction sequences, and, as such, testimony of local histories, identities and memories. It transmits cosmological and cosmogonic ideas as ceremonial centers and organizes the landscape, and thus can be defined as central places in an economic, political and social sense. As such, it is of major relevance to the establishment of interaction spheres.<br>Las reflexiones finales enfatizan la relevancia de esta colección sustancial de contribuciones. De particular importancia es la arquitectura monumental, que se inicia de manera muy temprana y se presenta en forma de secuencias. Esta arquitectura, por lo tanto, define historias locales, transmite identidad, memoria, así como ideas cosmológicas y cosmogónicas en su calidad de centro ceremonial, organiza el paisaje y se establece como lugar central en un sentido económico, social y político. Como tal desempeña un papel sustancial en las esferas de interacción.
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Escobedo, Mateus Beluca. "O protagonismo do educando na construção de jogos e sua replicabilidade em sala de aula como instrumento de fixação e recuperação contínua." Universidade Federal de São Carlos, 2016. https://repositorio.ufscar.br/handle/ufscar/8007.
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Previous issue date: 2016-06-23<br>Não recebi financiamento<br>This work related about games construction and application in classroom, aiming the development of
competence and ability prescribed in Sao Paulo State Curriculum, further helping the continuous
fixation and assistance. The topics are Sequences, Progressions and Volumes. Each content was
initially worked with chalk and board, and, then, valued. Posteriorly the games were built by the
students and applied in classroom. After the perception of necessary changes in one of the games,
the adjustments were made and the game was reapplied. The results were satisfactory, further having
significant possibility of improvement. The steps of the work are separately reported, from the content
choices to be worked, passing throughout didactic engineering (diagnostic assessment, planning,
implementation and evaluation) beside the results, in way to favor the proper understanding about the
work to provide the review of the importance of games as a relevant factor in mathematics teaching,
fixation and knowledge building.<br>Este trabalho trata da construção e aplicação de jogos em sala de aula objetivando o
desenvolvimento de competências e habilidades previstas no Currículo do Estado de
São Paulo, além da sua fixação e o auxílio na recuperação contínua. Os temas
abordados são Sequências, Progressões e Volumes. Cada conteúdo foi trabalhado
inicialmente com giz e lousa e, então, avaliado. Posteriormente os jogos foram
construídos pelos alunos e aplicados em sala de aula. Após a percepção das mudanças
necessárias em um dos jogos, os ajustes foram feitos e o jogo novamente aplicado. Os
resultados foram satisfatórios tendo ainda ampla possibilidade de melhora. As etapas do
trabalho estão relatadas separadamente, desde a escolha dos conteúdos a serem
trabalhados, passando por toda a engenharia didática (avaliação diagnóstica,
planejamento, aplicação e avaliação) além dos resultados, de modo a favorecer a
compreensão adequada sobre o trabalho para propiciar a análise da importância dos
jogos como fator relevante no ensino da Matemática, sua fixação e a construção do
conhecimento.
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Kuan-WeiChi and 紀冠瑋. "The fast stereo matching algorithm based on shared memory for HD image sequences." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/15892507806928980621.
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碩士<br>國立成功大學<br>電腦與通信工程研究所<br>103<br>In stereo matching algorithm, the local methods are considered as the approach balancing the speed and accuracy, besides the cross-based one is outstanding of them. In this essay, it’ll be based on the cross-based, although it has been a parallel algorithm, and if the algorithm can be applied the shared memory, it is going to speed up again. These steps which cannot be applied shared memory in cross-based method will be improved under the same principle without sacrificing the accuracy much.
Moreover, in the sequential image, there’s always something stationary (e.g. background), and it implies that we don’t have to calculate for each frames, and the information of the stationary part can be known from the previous. But the camera won’t be stationary, however fortunately it changes slightly. In the proposed method, we’ll detect the camera motion in period, and judge whether stationary or not with camera motion compensation. For the stationary part, we won’t calculate its support region, but copy these from previous instead.
For high-resolution image input, it’ll be restricted by hardware if the shared memory is applied. However, the information of each pixel is local so that we can divide the image into tiles and handle them one by one, and then combine them. Although it leads the overhead, it’ll be still worthwhile to do, considering the speed-up by shared memory.
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Tseng-WenChu and 朱增文. "Using Long Short-Term Memory Network for Anomaly Detection in System Call Sequences." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/scfc3e.
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Mau, William. "Neural patterns of hippocampus and amygdala supporting memory over long timespans." Thesis, 2019. https://hdl.handle.net/2144/38550.
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Episodic memory is an imperfect record of events arranged in time and space. When dealing with the storage of memories, the brain is faced with a predicament: it must retain an acceptably faithful facsimile of transpired events while simultaneously permitting inevitable modifications to accommodate learning new information. In this thesis, I first review contemporary theories of how memories can be stored in a neural substrate within the hippocampus, particularly in regards to how they can be arranged in time. Next, using in vivo calcium imaging, I detail how hippocampal “time cell” sequences could support encoding of behavioral events along multiple temporal dimensions. In this study, I trained mice to run in place on a treadmill, thereby measuring single-cell activity in CA1 as a function of time. Neurons in CA1 formed sequences, each cell firing one after another as if forming a scaffold upon which memories can be laid. These sequences were relatively well-preserved over a period of four days, satisfying the first requirement that information must be stored for a memory to persist. Additionally, these sequences also changed over time, which may be revealing a mechanism for how memories can change over time to assimilate new information. In the next experiment, I describe a collaborative project where we used immunohistochemistry, optogenetics, and calcium imaging to investigate the long-term dynamics of a fear memory. After mice initially associated a context with an aversive stimulus, they were placed in the same context over two days where they gradually relearned that the context was harmless. This produced molecular and neurophysiological signatures consistent with memory modification. However, after re-triggering fear, mice reverted to fearful expression with commensurate neural correlates. Using optogenetics, these behaviors could also be reliably suppressed. Finally, I conclude by synthesizing these findings with hippocampal literature on sequence formation and consolidation by proposing a holistic view of how these features can support episodic memory.
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Shiu, Liang-Cheng, and 許良政. "A Study on the Generation of Local Memory Access Sequences and Communication Sets for Data-Parallel Programs." Thesis, 2003. http://ndltd.ncl.edu.tw/handle/04453268404213534852.
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博士<br>國立中山大學<br>電機工程學系研究所<br>91<br>Distributed-memory multiprocessors offer very high levels of performance that are required to solve scientific applications. A traditional programming language cannot be expected to yield good performance when used to program such machines. Data-parallel languages provide programmers with a global memory and relieve them from the burden of inserting time-consuming, error-prone inter-processor communication. The compilers of these languages perform this task. Data-parallel languages also enable the programmers to establish alignment and distribution directives which specify the type of data parallelism and data mapping to the underlying parallel architecture.
Parallelizing compilers distribute data and generate code according to the owner-computes rule when compiling an array statement. The array elements in a processor it owns are only a fraction of all the array elements. Not all of the array elements in the processor are active elements, so determining local memory access sequence is important. However, generating local memory access sequences becomes rather complicated when the array references involve complex subscripts. This study considers two types of complex subscript ― coupled subscripts and multiple induction variables. A processor may refer to the rhs (right-hand side) array elements owned by other processors, and the movement of data is inevitable. The overhead to access non-local data by inter-processor communication may be around 10 to 100 times more than the cost of accessing local data. Efficiently generating communication sets is important.
This thesis introduces the concept of block compression/decompression, using smaller iteration tables, course distance and local block distance to solve problems of local memory access sequences, coupled scripts, MIV subscripts and communication set generation. Related work on these problems is reviewed and experimental results to demonstrate the benefit of the proposed methods.
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Baker, M. "Geochemistry and geochronology of palaeoproterozoic Fe-rich tholeiites and metasediments from the Georgetown Inlier, North Queensland : their petrogenesis, metamorphic history, tectonic setting, and implications for relationship with the Broken Hill and Mt Isa sequences." Thesis, 2007. https://eprints.utas.edu.au/26945/1/Baker_whole_thesis.pdf.
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Fe-rich tholeiites intruded the lower Etheridge Group of the Georgetown Inlier of north Queensland during the late-Palaeoproterozoic (ca. 1680-1640 Ma), during a prolonged period of rift-related sedimentation associated with extension in the Georgetown basin. The tholeiites comprise two lithologically distinct units: the extrusive Dead Horse Metabasalt (DHM), a conformable 1000m-thick series of fine- to coarse-grained basalts and pillow lavas; and the intrusive Cobbold Metadolerite (CMD), a multitude of sills and lesser dykes that range from a few metres to over 500 m in thickness. U-Pb LA-ICPMS dating of igneous zircons indicate the tholeiites were intruded in at least two pulses. The first coincided with the extrusion of the DHM and associated CMD sills at ca. 1670 Ma, while a younger pulse occurred during the deposition of the overlying Lane Creek Formation at ca. 1640 Ma.
The DHM and CMD are co-magmatic, and have compositions typical of relatively evolved, low-K, Fe-rich continental tholeiites and tholeiites generated in plume-triggered volcanic passive margins leading up to continental breakup. Immobile major and trace element patterns suggest that the tholeiites were derived from partial melting of the convecting depleted upper mantle depleted mantle melt, and melts evolved along a trend of increasing Fe-enrichment to strongly Fe-enriched (21.11 wt% total Fe as Fe\(_2\)O\(_3\)) ferro-tholeiites. Initial ε\(_{Nd}\) values range between +2.6 and +5.3 (average +4.0), confirming a depleted mantle source for the tholeiites. T\(_{DM}\) ages range between 1.85 Ga and 3.39 Ga (average 2.5 Ga). Several samples show slight LILE- and LREE-enrichment and have low initial ε\(_{Nd}\) values (+2.6-2.9) consistent with limited crustal contamination involving local host sedimentary rocks of the lower Etheridge Group.
Between ca. 1600 and 1500 Ma, the lower Etheridge Group was deformed and metamorphosed by at least two regionally significant orogenic events. The first event (D\(_1\)) was the most intense, producing a pervasive foliation and metamorphism (M\(_1\)) that varied in intensity from upper amphibolite facies in the east, through to lower greenschist facies in the south-west. Metasediments in the south of the inlier record P-T conditions of up to 650°C and 7.5 kbar for M\(_1\). D\(_1\) was followed by a period of retrogressive metamorphism that lasted until ca. 1550 Ma, when voluminous granitoids of the Forsayth Batholith were intruded into the lower Etheridge Group. High-temperature, low-pressure metamorphism (M\(_2\)) was associated with this event. Initial P-T conditions for M\(_2\) are inferred from a retrogressive mineral assemblage that returned conditions of 550°C and 3 kbar. EMPA monazite dating returned a possible ca. 1585 Ma age for M\(_1\) and a ca. 1550-1530 Ma age for M\(_2\). A younger monazite population (ca. 1500 Ma) suggests either M\(_2\) continued for a further 30-50 million years, or an additional weak thermal event affected the Etheridge Group at this time.
The DHM and CMD are broadly correlated temporally and geochemically to basic gneisses of the Broken Hill Group in the Willyama Inlier, and amphibolites of the Soldiers Cap Group in the Mt Isa Eastern Succession. In particular, immobile trace element ratios and REE patterns between these tholeiitic suites are virtually indistinguishable. The crystallisation ages of the DHM and CMD, as determined by U-Pb LA-ICPMS zircon dating also closely resembles established ages for the Broken Hill (ca. 1685 Ma) and Mt Isa Eastern Succession (ca. 1670 Ma) tholeiitic rocks. This relationship is of regional significance, as it suggests the terranes were spatially associated during the Palaeoproterozoic, and places the Georgetown Inlier within the Proterozoic framework of northern Australia, and likely a part of the North Australian Craton in the Palaeoproterozoic.