Since the field-defining patient HM, consistent links have been made between a region of the brain called the hippocampus and memories that can be consciously declared - so called declarative memories. Declarative memories fall into two categories (1) episodic memories, memories that are highly detailed and re-experiential, and (2) semantic memories, fact-based memories for personal and public information but that have no sense of re-experiencing. It is believed that the intrinsic anatomy of the hippocampus supports episodic memory but not semantic memory. The hippocampus consists of five regions (cornu Ammonis, CA, 1-3, dentate gyrus, subiculum) with each purported to have a specific role in episodic memory acquisition and retrieval. However, controversy surrounds the temporal extent to which episodic memories rely on the hippocampus for retrieval: current consensus suggests the hippocampus supports these memories for five-10 years post-acquisition, but some suggest that it is required for retrieval across the lifetime. Voltage-gated potassium channel-complex antibody-mediated limbic encephalitis (VGKC-complex LE) is a recently described autoimmune disease that causes chronic hippocampal atrophy and mild amnesia on standardized neuropsychological assessment. Two subfields of the hippocampus - CA1 and CA3 - contain the antigenic targets of the disease but it is unknown if specific atrophy of these subfields underlies the hippocampal damage in humans. Here, the human hippocampal subfield volumes of VGKC-complex LE patients (n = 19, mean age: 64.0±2.55; range: 24-71) were investigated using ultra-high spatial resolution MRI at 7.0-Tesla. Assessment also included standardized neuropsychology to examine the impact of the pathology on hippocampal-dependent and -independent memory performance, as well as attention, language, executive function, and perception Declarative memory assessment measured semantic and episodic memory performance across the lifespan. Manual segmentation detected lesions to just CA3, with no volume loss noted elsewhere in the hippocampus or brain. Patients were impaired on hippocampal-dependent memory domains but not the hippocampal-independent and non-memory domains. Notably, episodic memory assessment revealed episodic amnesia across the lifetime except for their earliest memories. This counters the received convention that the hippocampus has a temporally limited role in episodic retrieval. Conversely, the performance of the VGKC-complex LE patients for semantic memory, including a new test developed herein, was comparable to controls across the lifespan. It was then shown that CA3 volume predicted episodic memory performance across the lifetime. Together, the results suggest that VGKC-complex LE provides a novel model of human hippocampal subfield pathology, with which to explore the roles of hippocampal subfields in episodic memory acquisition and retrieval.

Declarative process models define the behaviour of business processes as a set of constraints. Declarative process discovery aims at inferring such constraints from event logs. Existing discovery techniques verify the satisfaction of candidate constraints over the log, but completely neglect their interactions. As a result, the inferred constraints can be mutually contradicting and their interplay may lead to an inconsistent process model that does not accept any trace. In such a case, the output turns out to be unusable for enactment, simulation or verification purposes. In addition, the discovered model contains, in general, redundancies that are due to complex interactions of several constraints and that cannot be cured using existing pruning approaches. We address these problems by proposing a technique that automatically resolves conflicts within the discovered models and is more powerful than existing pruning techniques to eliminate redundancies. First, we formally define the problems of constraint redundancy and conflict resolution. Second, we introduce techniques based on the notion of automata-product monoid, which guarantees the consistency of the discovered models and, at the same time, keeps the most interesting constraints in the pruned set. The level of interestingness is dictated by user-specified prioritisation criteria. We evaluate the devised techniques on a set of real-world event logs.

Language production is characterized by an unlimited expressive capacity and creative flexibility that allows speakers to rapidly generate novel and complex utterances. In turn, listeners interpret language "on-line", incrementally integrating diverse representations to create meaning in real-time. A challenge for theories of language has been to understand how speakers generate, integrate, and maintain representations in service of language use and processing and how this is accomplished in the brain. Much of this work has focused prefrontal cortex mechanisms such as "working memory". The goal of this dissertation is to understand the role of the hippocampal declarative memory system (HDMS) in language use and processing, specifically in referential processing and narrative construction. To test the role of the hippocampus in referential processing, healthy comparisons, brain damaged comparisons (BDC), individuals with bilateral hippocampal damage participated in an eyetracking experiment in which individuals viewed scenes and listened to short stories. The amount of time participants spent looking at the characters after a pronoun reference was recorded. Healthy comparisons and BDC participants preferentially targeted the first mentioned character while participants with hippocampal damage did not, suggesting that the hippocampus plays a role in maintaining and integrating information, even in short discourse history. In a second experiment, participants with bilateral hippocampal damage and healthy comparisons told narratives multiple times over the course of a month. The narratives were analyzed for the number of words, the number of episodic details, the number of semantic details, the number of editorials and the consistency of details over the multiple tellings. The patients with hippocampal damage told stories that were significantly shorter, more semanticized and less consistent from telling to telling than healthy comparisons. The final goal of this study was to understand the effects of unilateral hippocampal damage on language processing. Individuals with unilateral hippocampal damage participated in all of the previous experiments. It was predicted that individuals with left hippocampal damage would perform worse than individuals with right hippocampal damage, and their performance was significantly impaired across measures. This suggests that the left hippocampus may be particularly important for processing linguistic material outside of even verbal memory.

A runtime file system checker protects file-system metadata integrity. It checks the consistency of file system update operations before they are committed to disk, thus preventing corrupted updates from reaching the disk. In this thesis, we describe our experiences with building Brunch, a runtime checker for an emerging Linux file system called Btrfs. Btrfs supports many modern file-system features that pose challenges in designing a robust checker. We find that the runtime consistency checks need to be expressed clearly so that they can be reasoned about and implemented reliably, and thus we propose writing the checks declaratively. This approach reduces the complexity of the checks, ensures their independence, and helps identify the correct abstractions in the checker. It also shows how the checker can be designed to handle arbitrary file system corruption. Our results show that runtime consistency checking is still viable for complex, modern file systems.

<p>Memories are not veridical representations of the environment. Rather, an individual's goals can influence how the surrounding environment is represented in long-term memory. The present dissertation aims to delineate the influence of reward and punishment motivation on human declarative memory encoding and its underlying neural circuitry. Chapter 1 provides a theoretical framework for investigating motivation's influence on declarative memory. This chapter will review the animal and human literatures on declarative memory encoding, reward and punishment motivation, and motivation's influence on learning and memory. Chapter 2 presents a study examining the behavioral effects of reward and punishment motivation on declarative memory encoding. Chapter 3 presents a study examining the neural circuitry underlying punishment-motivated declarative encoding using functional magnetic resonance imaging (fMRI), and compares these findings to previous studies of reward-motivated declarative encoding. Chapter 4 presents a study examining the influence of reward and punishment motivation on neural sensitivity to and declarative memory for unexpected events encountered during goal pursuit using fMRI. Finally, Chapter 5 synthesizes these results and proposes a model of how and why motivational valence has distinct influences on declarative memory encoding. Results indicated that behaviorally, reward motivation resulted in more enriched representations of the environment compared to punishment motivation. Neurally, these motivational states engaged distinct neuromodulatory systems and medial temporal lobe (MTL) targets during encoding. Specifically, results indicated that reward motivation supports interactions between the ventral tegmental area and the hippocampus, whereas, punishment motivation supports interactions between the amygdala and parahippocampal cortex. Together, these findings suggest that reward and punishment engage distinct systems of encoding and result in the storage of qualitatively different representations of the environment into long-term memory.</p> / Dissertation

Thesis (Ph. D.)--University of Kentucky, 2001. / Title from document title page. Document formatted into pages; contains vii, 75 p. : ill. Includes abstract. Includes bibliographical references (p. 70-72).

Solution of any search problem lies in its search space. A search is a systematic examination of candidate solutions of a search problem. In this thesis, we present a search heuristic that we can cr-smodels. cr-smodels prunes the search space to quickly reach to the solution of a problem. The idea is to pick an atom for branching , that lowers the growth rate of the linear recurrence and thuse, minimizes the remaining search space. Our goal in developing cr-smodels is to develop a search heuristic that is efficient on a wide range of problems. Then, we test cr-smodels over a wide range of randomly generated benchmarks. we observed that often randomly generated graphs with no Hamiltonian cycle were trivial to solve. Since, Hamiltonian cycle is an important benchmark problem, my other goal is to develop techniques that generate hard instances of graphs with no Hamiltonian cycle.

A runtime file system checker protects file-system metadata integrity. It checks the consistency of file system update operations before they are committed to disk, thus preventing corrupted updates from reaching the disk. In this thesis, we describe our experiences with building Brunch, a runtime checker for an emerging Linux file system called Btrfs. Btrfs supports many modern file-system features that pose challenges in designing a robust checker. We find that the runtime consistency checks need to be expressed clearly so that they can be reasoned about and implemented reliably, and thus we propose writing the checks declaratively. This approach reduces the complexity of the checks, ensures their independence, and helps identify the correct abstractions in the checker. It also shows how the checker can be designed to handle arbitrary file system corruption. Our results show that runtime consistency checking is still viable for complex, modern file systems.

Research in corrective feedback (CF) has developed over thirty years; however, little is known about how metalinguistic corrective feedback (MCF) assists the development of procedural knowledge. This quasi-experimental study sought to evaluate and compare the roles of oral MCF in proceduralizing English as a foreign language (EFL) learners’ declarative knowledge of gender referents and morphosyntactical structure—third person singular -s. Sixty college EFL learners participated in the study. They were randomly assigned to the experimental group and the control group. All learners participated in 14 communicative form-focused activities that elicited the use of gender referents and third person singular morpheme -s in regular classes over 14 weeks. The experimental group received MCF on errors in use of the target structures. The control group received no MCF in use of the target structures. Pretests, posttests, and long delayed posttests administered 20 weeks after the instructional treatment assessed the participants’ declarative knowledge and procedural knowledge of both target structures. The metalinguistic knowledge test was employed to measure declarative knowledge. The elicited oral imitation test was adopted to measure procedural knowledge. Repeated measures ANOVA results indicated that the MCF group significantly increased their procedural knowledge of both target structures. Cohen’s effect size d revealed that MCF exerted a bigger effect on proceduralizing EFL learners’ knowledge on third person singular morpheme –s than on gender referents. These results also demonstrated a relationship between the efficacy of oral MCF and the target structures as well as the interactional effect of test formats tapping into declarative knowledge and procedural knowledge. These findings shed light on the learnability of difficult structures through MCF and the necessity to employ metalanguage in EFL classrooms.

The long-term memory system for what is conscious and can be verbalized – declarative memory- is often separated into memory for general facts and memory for personal events (Squire, 2009; Tulving, 2002). Personal semantics share elements of both semantic memory (i.e., they are facts that can be known) and episodic memory (i.e., they are self-related and idiosyncratic; Renoult, Davidson, Palombo, Moscovitch, & Levine, 2012). According to the taxonomy of personal semantics (Renoult et al., 2012), they vary in proximity to either semantic or episodic memory. Towards one end of the continuum, memory for autobiographical facts such as jobs and names of friends were hypothesized to be closer to general facts. Towards the other end of the continuum, repeated events are summaries of the core elements of similar events that happened more than once (e.g., getting coffee at a coffee shop), and they were hypothesized to be closer to episodic memory (i.e., the recollection of a unique event). Self-knowledge involves self-reflection about one’s own personality traits and preferences; it was thought to be the most distinct from semantic and episodic memory. However, little research had compared personal semantics to both semantic and episodic memory, or to one another, and these proposals needed to be tested experimentally. In this thesis, I compared the neural correlates of three types of personal semantics to semantic memory (study 1, 2, 3) and episodic memory (study 1, 2), and to one another (study 1) using functional magnetic resonance imaging (fMRI; study 1) and event related potentials (ERPs; study 2, 3). Moreover, I examined whether temporal orientation modified the personal semantics’ relationship to the typically atemporal semantic memory (study 2, 3) and to the typically past-oriented episodic memory (study 2). In study 1, general facts, autobiographical facts, repeated events, and unique events were compared using fMRI, in a follow-up to an ERP study (Renoult et al., 2016). In our analyses of the hippocampus (HPC) and posterior medial network (Ritchey, Libby, & Ranganath, 2015), general semantics and autobiographical facts were often not significantly different from one another (except for the left posterior HPC), and repeated events and unique events did not differ from one another in any comparison. I observed a small graded increase of brain activity from general facts to autobiographical facts to repeated events and unique events (with a significant linear trend) in the left posterior HPC. In contrast, no memory type differed in the anterior temporal network (Ritchey et al., 2015). In study 2 and 3, self-knowledge was operationalized as the knowledge of one’s own traits, and could concern past (study 2), present (study 2, 3) and future selves (study 2, 3). A neural correlate of recollection, the Late Positive Component (LPC), had a larger mean amplitude for thinking about the self than others (study 2, 3), and thinking about a past and/or future self than the present self (on average for study 2, and significant for study 3). The amplitude of the LPC for thinking about the past and future selves did not differ from an episodic recognition memory task (or present self-knowledge; study 2). Further, the temporal orientation effect was smaller and not significant when we compared thinking about the present and the future traits of others (study 3). The operationalization of the “other” as a close friend or a group of people did not modify this result (study 3). Together, in addition to Renoult et al. (2016), these findings suggest that: the neural correlates of autobiographical facts, repeated events, and self-knowledge do not overlap perfectly with semantic or episodic memory. Moreover, the temporal orientation of the knowledge is one factor that can influence the proximity of the neural correlates of personal semantics to either semantic or episodic memory.