• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 26
  • 5
  • 5
  • 2
  • 2
  • 1
  • 1
  • Tagged with
  • 57
  • 24
  • 22
  • 21
  • 18
  • 12
  • 10
  • 10
  • 8
  • 7
  • 7
  • 6
  • 6
  • 6
  • 6
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
41

Associative recognition : exploring the contributions of recollection and familiarity

Murray, Jamie G. January 2014 (has links)
Episodic memory refers to the storage and retrieval of information about events in our past. According to dual process models, episodic memory is supported by familiarity which refers to the rapid and automatic sense of oldness about a previously encoded stimulus, and recollection which refers to the retrieval of contextual information, such as spatial, temporal or other contextual details that bring a specific item to mind. To be clear, familiarity is traditionally assumed to support recognition of item information, whereas recollection supports the recognition of associative information. Event Related Potential (ERP) studies provide support for dual process models, by demonstrating qualitatively distinct patterns of neural activity associated with familiarity (Mid-Frontal old/new effect) and recollection (Left-Parietal old/new effect). In the current thesis, ERPs were used to address two important questions regarding associative recognition – namely, the function of the neural signal supporting recollection and whether familiarity can contribute to the retrieval of novel associative information. The first series of experiments was aimed at addressing how recollection operates by employing a recently developed continuous source task designed to directly measure the accuracy of retrieval success. To date, the function of recollection has been fiercely debated, with some arguing that recollection reflects the operation of a continuous retrieval process, whereby test cues always elicit some information from memory. Alternatively, recollection may reflect the operation of a thresholded process that allows for retrieval failure, whereby test cues sometimes elicit no information from memory at all. In the current thesis, the Left Parietal effect was found to be sensitive to the precision of memory responses when recollection succeeded, but was entirely absent when recollection failed. The result clarifies the nature of the neural mechanism underlying successful retrieval whilst also providing novel evidence in support of threshold models of recollection. The second series of experiments addressed whether familiarity could contribute to the retrieval of novel associative information. Recent associative recognition studies have suggested that unitization (whereby multi-component stimuli are encoded as a single item rather than as a set of associated parts) can improve episodic memory by increasing the availability of familiarity during retrieval. To date, however, ERP studies have failed to provide any evidence of unitization for novel associations, whereas behavioural support for unitization is heavily reliant on model specific measures such as ROC analysis. Over three separate associative recognition studies employing unrelated word pairs, the magnitude of the Mid-Frontal old/new effect was found to be modulated by encoding instructions designed to manipulate the level of unitization. Importantly, the results also suggest that different encoding strategies designed to manipulate the level of unitization may be more successful than others. Finally, the results also revealed that differences in behavioural performance and modulation of the Mid-Frontal old/new effect between unitized and non-unitized instructions is greater for unrelated compared to related word pairs. In essence, the results suggest that unitization is better suited to learning completely novel associations as opposed to word pairs sharing a pre-existing conceptual relationship. Overall, the data presented in this thesis supports dual process accounts of episodic memory, suggesting that at a neural level of analysis, recollection is both thresholded and variable, whilst also supporting the assumption that familiarity can contribute to successful retrieval of novel associative information. The results have important implications for our current understanding of cognitive decline and the development of behavioural interventions aimed at alleviating associative deficits.
42

Separate and concurrent symbolic predictions of sound features are processed differently

Pieszek, Marika, Schröger, Erich, Widmann, Andreas 28 November 2014 (has links) (PDF)
The studies investigated the impact of predictive visual information about the pitch and location of a forthcoming sound on the sound processing. In Symbol-to-Sound matching paradigms, symbols induced predictions of particular sounds. The brain’s error signals (IR and N2b components of the event-related potential) were measured in response to occasional violations of the prediction, i.e. when a sound was incongruent to the corresponding symbol. IR and N2b index the detection of prediction violations at different levels, IR at a sensory and N2b at a cognitive level. Participants evaluated the congruency between prediction and actual sound by button press. When the prediction referred to only the pitch or only the location feature (Exp. 1), the violation of each feature elicited IR and N2b. The IRs to pitch and location violations revealed differences in the in time course and topography, suggesting that they were generated in feature-specific sensory areas. When the prediction referred to both features concurrently (Exp. 2), that is, the symbol predicted the sound´s pitch and location, either one or both predictions were violated. Unexpectedly, no significant effects in the IR range were obtained. However, N2b was elicited in response to all violations. N2b in response to concurrent violations of pitch and location had a shorter latency. We conclude that associative predictions can be established by arbitrary rule-based symbols and for different sound features, and that concurrent violations are processed in parallel. In complex situations as in Exp. 2, capacity limitations appear to affect processing in a hierarchical manner. While predictions were presumably not reliably established at sensory levels (absence of IR), they were established at more cognitive levels, where sounds are represented categorially (presence of N2b).
43

Electrophysiological and neuropsychological assessment of automatic and controlled processing aspects of attention after mild traumatic brain injury

Rogers, Jeffrey Michael January 2007 (has links)
[Truncated abstract] Controlled and automatic processing are broad categories, and how best to measure these constructs and their impact on functioning after mild traumatic brain injury (TBI) remains uncertain. The purpose of this thesis was to examine automatic and controlled processing aspects of attention after mild TBI using the Paced Auditory Serial Addition Task (PASAT) and event-related potentials (ERPs). The PASAT is one of the most frequently used tests to evaluate attentional functioning. It has been demonstrated to be a measure sensitive to both acute and longer-term effects of mild TBI, presumably due to demands for rapid processing and executive attentional control. ERPs provide a noninvasive neurophysiological index of sensory processing and cognitive functions and have demonstrated sensitivity to even minor cognitive dysfunction. The parameters provided by this functional technique may be those most likely to distinguish individuals with mild TBI from controls. Initially, it was hypothesized that successful novice PASAT performance requires the engagement of executive attention to establish novel controlled information processing strategies. Ten individuals who had suffered a mild TBI an average of 15.20 months previously were therefore expected to demonstrate processing abnormalities on the PASAT, relative to 10 healthy matched controls. Although the mild TBI group reported significant intensification of subjective symptoms since their injury, compared to controls, the mild TBI group provided a similar amount of correct PASAT responses. ... In the first experiment a visual search task consisting of an automatic detection and a controlled search condition was developed. In the second experiment the search task was performed concurrently with the PASAT task in a dual-task paradigm. In the mild TBI group, prior failure to establish more efficient forms of information processing with practice was found to significantly interfere with simultaneous performance of the PASAT task and the attention demanding condition of the search task. The pattern of impaired performance was considered to reflect a reduction in processing resources rather than a deficit in resource allocation. Dual-task performance in the control group was not associated with a large interference effect. In general, the results of this thesis suggest that individuals with mild TBI are impaired in their ability to progress from the stage of effortful controlled information processing to a stage of more efficient, automatic processing, and thus suffer a subtle attentional deficit. Following mild TBI, performance levels equivalent to controls may only be achieved with an abnormal expenditure of cognitive effort. As a result of the neuropathologic consequences of injury, individuals who have sustained a mild TBI are less able to benefit from practice, experience difficulty coping with simultaneous performance of secondary task, and are susceptible to distressing subjective symptomatology.
44

Critical Success Factors for Integration of Enterprise Resource Planning System

Kafi, Kambiz January 2018 (has links)
Title: Critical Success Factors for Integration of Enterprise Resource Planning System   Level: Student thesis, final assignment for Master Degree (one year) in Business Administration   Author: Kambiz Kafi   Supervisor: Dr. Maria Fregidou-Malama   Examiner: Dr. Ehsanul Huda Chowdhury   Date: 2018-11-26   Aim: This study examines the Critical Success Factor (CSF) model and its implementation in a case study where ERP Systems are integrated. The model includes Legacy System as a CSF.   Method: Deductive reasoning and case study were applied to support the research theory. Primary and secondary data were collected. Interviews with managers and staffs were performed.   Result & Conclusions: The study shows the factors that are critical in successful implementation of ERP project and how a successful implementation and integration of ERP projects is executed when two companies are being merged. It also shows how the ERP integration project can be implemented. This work studied an implementation of Holland and Light’s theoretical CSF model empirically and validated that the model is general and robust for successful ERP implementation and managing changes.   Contribution of the research: This study of integration of few Legacy Systems when companies are being merged is a contribution to the theory of CSF. The central role that Legacy Systems plays in ERP project implementation is shown empirically. This study presents Software Alignment (Software Configuration) based on two company’s business processes empirically and found it to be essential in success of ERP projects. The research shows how CSF model manages changes, assisting managers in merging two companies successfully. The research presents a modified Holland and Light CSF model to meet the merging situations.      Suggestions for future research: To gain more knowledge about CSFs for integration of ERPs, this study suggests further cross- industrial empirical studies in wholesale and retail industries with varied sizes. Research about identifying CFSs in extended ERP using e_CRM is recommended.
45

Vilken roll spelar ekonomen? : Redovisningsekonomers och controllers yrkesroller givet ett integrerat redovisningssystem och harmonisering av extern- och internredovisning / What role does the accountant play? : Financial and management accountants’ professional roles provided the use of an integrated accounting system and harmonization of financial and management accounting

Sundström, David, von Schoultz, Axel January 2017 (has links)
Bakgrund:  Denna studie tar sin utgångspunkt i två kontextuella förutsättningar som i akademisk litteratur sägs påverka möjligheterna för hur redovisningsekonomers och controllers roller i företag utformas och förändras. Den första förutsättningen grundas i utvecklingen av informationssystem, däribland integrerade redovisningssystem, vilket i grunden förändrat sätten information kan framställas, användas och omsättas i företag. Den andra förutsättningen tar sin utgångspunkt i en pågående akademisk debatt om förhållandet mellan extern- och internredovisning. Flera forskare har uppmärksammat att dessa forskningsområden särskiljs i akademisk litteratur, medan extern- och internredovisning i praktiken, enligt vissa forskare, närmat sig varandra. Vad detta, sammantaget med utvecklingen av informationssystem, ger för möjligheter att utforma redovisningsekonomers och controllers yrkesroller har i tidigare studier lyfts fram som ett intressant forskningsområde. Syfte:  Syftet med denna studie är att öka förståelsen för hur redovisningsekonomers och controllers yrkesroller utvecklas och utformas i och med användning av ett integrerat redovisningssystem och en harmonisering av extern- och internredovisning. Metod:  I studien tillämpas en kvalitativ metod där det empiriska materialet består av intervjuer inom en ekonomifunktion. Studien har genomförts som en fallstudie med longitudinella inslag. Slutsats och diskussion:  Studiens resultat visar tecken på en hybridisering av redovisningsekonomens och controllerns yrkesroller i och med användning av ett integrerat redovisningssystem och en harmonisering av extern- och internredovisning. Dessa kontextuella förutsättningarna kan sägas ha möjliggjort denna hybridisering, men kan dock inte sägas vara de definitiva orsakerna till denna. / Background:  This thesis is based on two contextual conditions that in academic literature are said to affect the possibilities of how financial and management accountants’ roles can be designed and changed. The first condition is based in the development of information systems, including integrated accounting systems, which are said to have fundamentally changed the ways information is produced, used, and treated within organizations. The second condition is based on an ongoing academic debate regarding the relation between financial and management accounting. Several researchers have noted that these research areas have diverted in academic literature, while the relationship in practice, as suggested by some researchers, is the opposite. The opportunities in this context to design and change management and financial accountants’ roles have, in previous studies, been presented as an interesting research area. Purpose:  The purpose of this thesis is to gain a better understanding of how financial and management accountants’ roles evolve and are designed provided the use of an integrated accounting system and harmonization of financial and management accounting. Research method:  The study is based on a qualitative approach where the empirical data consists of interviews with employees within an accounting department. The study has been conducted as a single case study with longitudinal aspects. Conclusion:  Results from this study indicate signs of a hybridization of financial and management accountants’ roles provided the use of an integrated accounting system and harmonization of financial and management accounting. These conditions could possibly facilitate this hybridization, but cannot be said to be the definitive cause of it.
46

ERP Analyses of Perceiving Emotions and Eye Gaze in Faces: Differential Effects of Motherhood and High Autism Trait

Bagherzadeh-Azbari, Shadi 08 May 2023 (has links)
Die Blickrichtung und ihre Richtung sind wichtige nonverbale Hinweise für die Etablierung von sozialen Interaktionen und die Wahrnehmung von emotionalen Gesichtsausdrücken bei anderen. Ob der Blick direkt auf den Betrachter gerichtet ist (direkter Blick) oder abgewendet (abgewandter Blick), beeinflusst unsere soziale Aufmerksamkeit und emotionale Reaktionen. Dies deutet darauf hin, dass Emotionen und Blickrichtung informative Werte haben, die sich möglicherweise in frühen oder späteren Stadien der neurokognitiven Verarbeitung interagieren. Trotz theoretischer Grundlage, der geteilten Signal-Hypothese (Adams & Kleck, 2003), gibt es einen Mangel an strukturierten elektrophysiologischen Untersuchungen zu den Wechselwirkungen zwischen Emotionen und Blickrichtung sowie ihren neuronalen Korrelaten und wie sie sich in verschiedenen Bevölkerungsgruppen unterscheiden. Um diese Lücke zu schließen, verwendete diese Doktorarbeit ereigniskorrelierte Hirnpotentiale (ERPs), um die Reaktionen auf emotionale Ausdrücke und Blickrichtung in einem neuen Paradigma zu untersuchen, das statischen und dynamischen Blick mit Gesichtsausdrücken kombiniert. Es wurden drei verschiedene Populationen untersucht. Studie 1 untersuchte in einer normalen Stichprobe die Amplituden der ERP-Komponenten, die durch die erstmalige Präsentation von Gesichtern und nachfolgende Änderungen der Blickrichtung in der Hälfte der Durchgänge ausgelöst wurden. In Studie 2 wurden aufgrund der atypischen Gesichtsverarbeitung und verminderten Reaktionen auf Augenblick beim Autismus die ERPs und Augenbewegungen bei zwei Stichproben von Kindern mit unterschiedlichem Schweregrad ihrer Autismusmerkmale untersucht. In Studie 3 wurde in einer großen Stichprobe die vermutlich erhöhte Sensitivität bei der Emotionsverarbeitung und Reaktion auf Augenblick bei Müttern im postpartalen Zeitraum mit besonderem Fokus auf die Gesichter von Säuglingen untersucht. Zusammenfassend zeigen die Ergebnisse der drei Studien, dass in sozialen Interaktionen die emotionalen Effekte von Gesichtern durch die dynamische Blickrichtung moduliert werden. / The eye gaze and its direction are important and relevant non-verbal cues for the establishment of social interactions and the perception of others’ emotional facial expressions. Gaze direction itself, whether eyes are looking straight at the viewer (direct gaze) or whether they look away (averted gaze), affects our social attention and emotional response. This implies that both emotion and gaze have informational values, which might interact at early or later stages of neurocognitive processing. Despite the suggestion of a theoretical basis for this interaction, the shared signal hypothesis (Adams & Kleck, 2003), there is a lack of structured electrophysiological investigations into the interactions between emotion and gaze and their neural correlates, and how they vary across populations. Addressing this need, the present doctoral dissertation used event-related brain potentials (ERPs) to study responses to emotional expressions and gaze direction in a novel paradigm combining static and dynamic gaze with facial expressions. The N170 and EPN were selected as ERP components believed to reflect gaze perception and reflexive attention, respectively. Three different populations were investigated. Study 1, in a normal sample, investigated the amplitudes of the ERP components elicited by the initial presentation of faces and subsequent changes of gaze direction in half of the trials. In Study 2, based on the atypical face processing and diminished responses to eye gaze in autism, the ERPs and eye movements were examined in two samples of children varying in the severity of their autism traits. In Study 3, In a large sample, I addressed the putatively increased sensitivity in emotion processing and response to eye gaze in mothers during their postpartum period with a particular focus on infant's faces. Taken together, the results from three studies demonstrate that in social interactions, the emotional effects of faces are modulated by dynamic gaze direction.
47

The Brain Differentially Prepares Inner and Overt Speech Production: Electrophysiological and Vascular Evidence

Stephan, Franziska, Saalbach, Henrik, Rossi, Sonja 13 April 2023 (has links)
Speech production not only relies on spoken (overt speech) but also on silent output (inner speech). Little is known about whether inner and overt speech are processed differently and which neural mechanisms are involved. By simultaneously applying electroencephalography (EEG) and functional near-infrared spectroscopy (fNIRS), we tried to disentangle executive control from motor and linguistic processes. A preparation phase was introduced additionally to the examination of overt and inner speech directly during naming (i.e., speech execution). Participants completed a picture-naming paradigm in which the pure preparation phase of a subsequent speech production and the actual speech execution phase could be differentiated. fNIRS results revealed a larger activation for overt rather than inner speech at bilateral prefrontal to parietal regions during the preparation and at bilateral temporal regions during the execution phase. EEG results showed a larger negativity for inner compared to overt speech between 200 and 500 ms during the preparation phase and between 300 and 500 ms during the execution phase. Findings of the preparation phase indicated that differences between inner and overt speech are not exclusively driven by specific linguistic and motor processes but also impacted by inhibitory mechanisms. Results of the execution phase suggest that inhibitory processes operate during phonological code retrieval and encoding.
48

Inner versus Overt Speech Production: Does This Make a Difference in the Developing Brain?

Stephan, Franzisk, Saalbach, Henrik, Rossi, Sonja 13 April 2023 (has links)
Studies in adults showed differential neural processing between overt and inner speech. So far, it is unclear whether inner and overt speech are processed differentially in children. The present study examines the pre-activation of the speech network in order to disentangle domain-general executive control from linguistic control of inner and overt speech production in 6- to 7-year-olds by simultaneously applying electroencephalography (EEG) and functional near-infrared spectroscopy (fNIRS). Children underwent a picture-naming task in which the pure preparation of a subsequent speech production and the actual execution of speech can be differentiated. The preparation phase does not represent speech per se but it resembles the setting up of the language production network. Only the fNIRS revealed a larger activation for overt, compared to inner, speech over bilateral prefrontal to parietal regions during the preparation phase. Findings suggest that the children’s brain can prepare the subsequent speech production. The preparation for overt and inner speech requires different domain-general executive control. In contrast to adults, the children’s brain did not show differences between inner and overt speech when a concrete linguistic content occurs and a concrete execution is required. This might indicate that domain-specific executive control processes are still under development.
49

Event-Related Potentials Reflect the Affective Priming Capacity of Music on Speech

Morgan, Jacob January 2012 (has links)
<p>Music, like language, is a universal means of communication unique to humans, and the overlap of music and linguistic cognitive and neurological processes is well established. Performers and listeners alike are drawn to music as an avenue of emotional expression, as music is recognized for its rich emotional content. The study of affective priming indicates the communication of emotion-based concepts: stimuli that are related by affect give rise to response facilitation, an effect not observed to stimuli that are unrelated by affect. The measure of event-related brain potentials (ERPs) reveal, with exquisite temporal accuracy, that music clearly conveys emotion concepts in a manner commensurate to written language and prosody. To date, ERP studies of affective priming with music have involved written language and prosody, and have focused on the N400, an indication of semantic cognitive integration. The current study is the first to measure ERP responses in an affective priming paradigm of music and speech. In addition to the N400, the current study is the first of its kind to measure the N300, indicating cognitive categorization and the P300, reflecting recognition. Three sets of analyses – based on categorically correct responses, behaviourally correct responses and subjective responses – reveal N300 and N400 affective priming effects, corresponding to deliberate cognitive categorization and conceptual integration, respectively.</p> / Master of Science (MSc)
50

La saturation de la mémoire auditive à court terme, une étude en électrophysiologie

Alunni-Menichini, Kristelle 10 1900 (has links)
La présente étude vise à approfondir les connaissances relatives aux mécanismes neuronaux qui sous-tendent la maintenance de sons variant en hauteur dans la mémoire auditive à court terme (MACT), plus précisément lors de sa saturation. À cet effet, la technique des potentiels reliés aux évènements (PRE) en électrophysiologie a été utilisée. La sélection des participants s’est déroulée par l’entremise de deux expériences comportementales : l’une était une tâche de discrimination et l’autre, une tâche qui évaluait l’habileté générale des participants à réussir une tâche similaire à celle de l’expérience principale en électroencéphalographie (EEG). Les résultats comportementaux de notre tâche en EEG ont montré que la performance diminuait de façon significative plus la charge en mémoire augmentait (séquences de 2, 4, 6 et 8 sons) et que l’estimation de la capacité de la MACT mesurée par K augmentait entre 2 et 4 sons pour atteindre un plafond à 4 sons (effet plafond). Le K maximum étant de 2.84 sons, l’empan mnésique (EM) auditif semble être près de 3 sons. Les résultats électrophysiologiques ont montré que la composante électrophysiologique reliée à la maintenance de sons en MACT, la Sustained Anterior Negativity (SAN), était modulée par le nombre de sons à maintenir : son amplitude augmentait de 2 à 4 sons et ce, jusqu’à l’atteinte d’un plafond à 4 sons. Ces résultats suggèrent que la maintenance de sons additionnels dans la MACT n’est plus possible après sa saturation. Nous soutenons donc que la SAN est un index électrophysiologique de l’activité neuronale associée à la maintenance d’items auditifs dans la MACT et que son amplitude est un bon indicateur de la capacité individuelle de la MACT, estimée par K. Des résultats post-hoc ont démontré que les musiciens et les non-musiciens tendent à avoir des différences au niveau de la SAN, sans pour autant modifier l’effet de charge en mémoire. Une analyse qualitative et quantitative de l’utilisation des stratégies mnésiques ont permis de clarifier leur implication et leur nature au sein d’une tâche cognitive de mémoire, plus précisément en audition. Pour conclure, l’ensemble de ces résultats suggère également que la SAN est reliée à la maintenance de sons dans la MACT et ainsi, un bon indicateur de sa capacité. / The aim of the current study is to further understand, through the use of event-related potentials (ERPs), the neural mechanisms that underlie the maintenance of pitch in auditory short-term memory (ASTM) after reaching the memory span. Two behavioral experiments were used to help perform the selection of the participants: the first one was an evaluation of the acoustic discrimination and the second one was a general evaluation of participants’ ability to succeed to a similar task of the one that will be used in the electrophysiological (EEG) part of the experiment. Behavioral results from the EEG task showed a significant decrease in accuracy when the load increased (sequences of 2, 4, 6 and 8 tones). The estimation of the memory capacity (named K), increased from load 2 to 4 and reached a plateau after 4 tones. The maximum K represented 2.84 tones; the auditory span seems to be around 3 tones. Experimental results showed that the ERP component related to the maintenance of tones in ASTM, as measured by the Sustained Anterior Negativity (SAN), was modulated by the load. More specifically, its amplitude increased when the load increased (from 2 to 4) and reached a plateau at load 4. These results suggest that the maintenance of additional tones in ASTM is not possible after its saturation. Thus, the SAN appears to be an adequate electrophysiological index of neuronal activity related to the maintenance of tones in ASTM, and its amplitude appears to be predicted by K. Post-hoc results showed that musician and non-musicians tend to have some differences in their electrophysiological results; however, no change related to the load effect was observed. Finally, a qualitative and quantitative analysis was done to investigate the impact of the use of different mnemonic strategies in ASTM. Taking together, our results support that the SAN component is related to the maintenance of tones in ASTM and can be considerate as a good indicator of its capacity.

Page generated in 0.4173 seconds