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A PARALLEL -SEQUENTIAL SEARCH ALGORITHM IN A HIGH DYNAMIC GPS RECEIVERXingyu, Luo, Qishan, Zhang 10 1900 (has links)
International Telemetering Conference Proceedings / October 21, 2002 / Town & Country Hotel and Conference Center, San Diego, California / It is need to design acquisition and tracking for code loop and carrier loop to detect the high dynamic Global Position System (GPS) signal. Acquiring signal quickly and shortening acquisition time in the cold case are key technology of a high dynamic GPS receiver. Moreover, fast acquisition of C/A code is the base of code tracking and carrier acquisition and tracking. This paper describes elements and implementation of a new parallel-sequential search Algorithm to acquire C/A code of the high dynamic GPS signal. And combined with a 12-channel correlator named GP2021 produced by GEC Co., the arithmetic implementation to acquire C/A code of the high dynamic GPS signal used sequential search based on DSP technology is also given.
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Research and Recommendation of Optimum Group Synchronization Codes for N = 7 -- 32Zhongkui, Lei, Qiucheng, Xie, Jie, Cao 10 1900 (has links)
International Telemetering Conference Proceedings / October 17-20, 1988 / Riviera Hotel, Las Vegas, Nevada / In this paper, based on a series of research achievements [2,3,4,5,6], are examined the "The Optimum Frame Synchronization Codes" provided by J. L. Maury Jr. and F. J. Styles for IRIG Telemetry Standards USA, and furthermore, recommended a set of Optimum Group Synchronization Codes for China Telemetry Standards.
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Cognitive Mechanisms of False Facial RecognitionEdmonds, Emily Charlotte January 2011 (has links)
Face recognition involves a number of complex cognitive processes, including memory, executive functioning, and perception. A breakdown of one or more of these processes may result in false facial recognition, a memory distortion in which one mistakenly believes that novel faces are familiar. This study examined the cognitive mechanisms underlying false facial recognition in healthy older and younger adults, patients with frontotemporal dementia, and individuals with congenital prosopagnosia. Participants completed face recognition memory tests that included several different types of lures, as well as tests of face perception. Older adults demonstrated a familiarity-based response strategy, reflecting a deficit in source monitoring and impaired recollection of context, as they could not reliably discriminate between study faces and highly familiar lures. In patients with frontotemporal dementia, temporal lobe atrophy alone was associated with a reduction of true facial recognition, while concurrent frontal lobe damage was associated with increased false recognition, a liberal response bias, and an overreliance on "gist" memory when making recognition decisions. Individuals with congenital prosopagnosia demonstrated deficits in configural processing of faces and a reliance on feature-based processing, leading to false recognition of lures that had features in common from study to test. These findings may have important implications for the development of training programs that could serve to help individuals improve their ability to accurately recognize faces.
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Anomaly-based correlation of IDS alarmsTjhai, Gina C. January 2011 (has links)
An Intrusion Detection System (IDS) is one of the major techniques for securing information systems and keeping pace with current and potential threats and vulnerabilities in computing systems. It is an indisputable fact that the art of detecting intrusions is still far from perfect, and IDSs tend to generate a large number of false IDS alarms. Hence human has to inevitably validate those alarms before any action can be taken. As IT infrastructure become larger and more complicated, the number of alarms that need to be reviewed can escalate rapidly, making this task very difficult to manage. The need for an automated correlation and reduction system is therefore very much evident. In addition, alarm correlation is valuable in providing the operators with a more condensed view of potential security issues within the network infrastructure. The thesis embraces a comprehensive evaluation of the problem of false alarms and a proposal for an automated alarm correlation system. A critical analysis of existing alarm correlation systems is presented along with a description of the need for an enhanced correlation system. The study concludes that whilst a large number of works had been carried out in improving correlation techniques, none of them were perfect. They either required an extensive level of domain knowledge from the human experts to effectively run the system or were unable to provide high level information of the false alerts for future tuning. The overall objective of the research has therefore been to establish an alarm correlation framework and system which enables the administrator to effectively group alerts from the same attack instance and subsequently reduce the volume of false alarms without the need of domain knowledge. The achievement of this aim has comprised the proposal of an attribute-based approach, which is used as a foundation to systematically develop an unsupervised-based two-stage correlation technique. From this formation, a novel SOM K-Means Alarm Reduction Tool (SMART) architecture has been modelled as the framework from which time and attribute-based aggregation technique is offered. The thesis describes the design and features of the proposed architecture, focusing upon the key components forming the underlying architecture, the alert attributes and the way they are processed and applied to correlate alerts. The architecture is strengthened by the development of a statistical tool, which offers a mean to perform results or alert analysis and comparison. The main concepts of the novel architecture are validated through the implementation of a prototype system. A series of experiments were conducted to assess the effectiveness of SMART in reducing false alarms. This aimed to prove the viability of implementing the system in a practical environment and that the study has provided appropriate contribution to knowledge in this field.
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Perception And Theory-of-Mind Development In Preschool Children: Comparing Visual And Auditory ModalitiesHasni, Anita A 11 August 2015 (has links)
Research on theory of mind (ToM) has been dominated by the traditional False Belief tasks; however, recent work has established a developmental sequence for children’s mental-state understanding. Wellman and Liu (2004) formulated a ToM scale that tests four additional aspects of ToM abilities in the visual realm: Diverse Desires, Diverse Beliefs, Knowledge Access, and Real-Apparent Emotions. Our study extended the scale to include five parallel tasks assessing ToM in the auditory realm. Sixty-six typically developing preschoolers (30 female) between the ages of 3- and 5-years-old were tested using 10 ToM tasks (5 visual, 5 auditory). A 3(age) x 2(modality) x 2(gender) repeated measures ANOVA yielded significant effects for age and gender, where 4- and 5-year-olds demonstrated greater mental-state understanding than 3-year-olds and girls passed more tasks than boys. There was no effect of modality nor did any interactions emerge. Like the visual tasks in the theory-of-mind scale, the auditory tasks form a scalable set, with Diverse Desires and Diverse Beliefs occurring earlier in the scale than Knowledge Access, False Belief, and Real-Apparent Emotions. Our new scale provides researchers with five novel tasks to measure the progression of theory-of-mind development in the auditory realm and may be extended to assess preschoolers, such as children with visual impairments and children with autism spectrum disorder, who have shown delays in mental-state understanding when tested using predominantly visual tasks
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Lowering the Number of False Positive Responses to Electric Pulp Tests by Qualifying Patient ResponseLee, Katherine JS 01 January 2015 (has links)
The electric pulp test (EPT) has been shown to be a valuable tool in assessing pulp vitality. One of its drawbacks, however, is its high number of false positives. The purpose of this study was to determine if qualifying the type of sensation elicited by the test could lower the percentage of false positive responses. A retrospective chart review of an eleven-month period was conducted, examining all patients with necrotic teeth tested with the EPT. Of 189 teeth, when the patient responded to EPT at first sensation 23.3% of teeth were incorrectly identified as vital. When the patient was asked to respond only if they felt an uncomfortable sensation, the false positive rate was lowered to 8.5%, a statistically significant difference. No association was found between the teeth reclassified as necrotic and age, gender, type of tooth, or number of canals.
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A Study on False Information Injection Attack on Dynamic State Estimation in Multi-Sensor SystemsLu, Jingyang 01 January 2015 (has links)
In this thesis, the impact of false information injection is investigated for linear dynamic systems with multiple sensors. It is assumed that the Kalman filter system is unaware of the existence of false information and the adversary is trying to maximize the negative effect of the false information on the Kalman filter's estimation performance. First, a brief introduction to the Kalman filter is shown in the thesis. We mathematically characterize the false information attack under different conditions. For the adversary, many closed-form results for the optimal attack strategies that maximize the Kalman filter's estimation error are theoretically derived. It is shown that by choosing the optimal correlation coefficients among the bias noises and allocating power optimally among sensors, the adversary could significantly increase the Kalman filter's estimation errors. To be concrete, a target tracking system is used as an example in the thesis. From the adversary's point of view, the best attack strategies are obtained under different scenarios, including a single-sensor system with both position and velocity measurements, and a multi-sensor system with position and velocity measurements. Under a constraint on the total power of the injected bias noises, the optimal solutions are solved from two perspectives: trace and determinant of the mean squared error matrix. Numerical results are also provided in order to illustrate the negative effect which the proposed attack strategies could inflict on the Kalman filter.
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Estudo sobre as implicações da ansiedade social nas falsas memórias. / Studies about the implications of social anxiety in false memoryPalma, Priscila de Camargo 27 August 2012 (has links)
Os processos mnemônicos são responsáveis por manter a qualidade e estabilidade de vida de todos os seres humanos, porém pesquisas vêm mostrando ao longo do tempo, que tais processos podem apresentar erros e distorções que podem mudar o curso de nossa vida. As falsas memórias são as recordações de situações, eventos que na realidade não ocorreram exatamente como nos recordamos. Inicialmente acreditava-se que eventos vividos e que possuíssem carga emocional associada, não eram passíveis de distorção, porém já se sabe que tais premissas não são necessariamente verdadeiras. Além disso, o nível de desajustamento e instabilidade emocional interfere para um maior número de falsas memórias. A ansiedade é uma resposta adaptativa, normal e passa a ser patológica quando é desproporcional diante da situação desencadeante. Quando a ansiedade é muito intensa, tende a gerar prejuízos em todas as esferas da vida, esta ansiedade adquire um significado clínico. Dentro os transtornos de ansiedade há um diagnóstico bastante prevalente chamado de Transtorno de Ansiedade Social (TAS). O presente trabalho visou comparar participantes adultos portadores de TAS e participantes adultos sem estes sintomas, investigando o efeito da emoção na performance da memória, para um evento testemunhado. Para o desenvolvimento do trabalho foi utilizada uma sequência de onze slides, acompanhados por duas versões narrativas, sendo uma sem impacto e outra carregada emocionalmente, além de uma Escala Subjetiva de Emoção e um teste de Memória autoaplicativo. O estudo contou com 137 participantes, que foram divididos em quatro grupos: indivíduos sem transtorno de ansiedade e narrativa sem impacto emocional, indivíduos sem transtorno de ansiedade e narrativa com impacto emocional, indivíduos com transtorno de ansiedade e narrativa sem impacto emocional e indivíduos com transtorno de ansiedade e narrativa com impacto emocional. Foram realizadas análises paramétricas utilizando as análises de Variância (ANOVA). Todos os tratamentos estatísticos utilizaram um < 0,05 para o teste de hipóteses e testes post hoc com correção para Bonferroni para identificar as possíveis diferenças encontradas. Os resultados sugerem que os participantes portadores de TAS, os quais foram submetidos à versão sem impacto emocional, obtiveram índices maiores de memória verdadeira, porém apresentaram também índices superiores de falsas memórias, em função do viés atencional característico desta população, sugerindo que a ansiedade social tem uma ação significativa sobre a performance de memória. / Mnemonic processes are responsible for keeping all human beings life quality and stability. However, research has shown that such processes can present mistakes and distortions which can change the course of life. False memories are memories of situations and events that did not happen exactly as remembered. At first, it was believed that events which happened and had an associated emotional load could not be distorted; however it is now known that such premise is not necessarily true. Moreover, it is known that the level of disadjustment and emotional instability interfere for a greater number of false memories. Anxiety is a normal adaptive response but it becomes pathologic when it is not proportional to the triggering situation. When anxiety is too intense, it tends to harm all spheres of life, and it acquires a clinical meaning. Amongst the anxiety disorders, there is a prevalent diagnosis called Social Anxiety Disorder (SAD). This study aims to compare adult participants who suffer from this problem with adult participants who do not have these symptoms, investigating the effect of emotion in memory performance for an event witnessed. To develop this study, a sequence of eleven slides was used, followed by two narrative versions, one with emotional impact and the other without, besides the Subjective Scale of Emotion, a self-test for memory. The study had 137 participants, who were divided into four groups: individuals who do not suffer from the disorder and emotionally loaded narrative, individuals who do not suffer from the disorder and narrative without emotional load, individuals who suffer from the disorder and emotionally loaded narrative, individuals who suffer from the disorder and narrative without emotional load. Parametrical analysis was carried out using the Variance analysis (ANOVA). All the statistical treatments used an < 0,05 for the hypothesis test and post hoc tests with correction for Bonferroni to identify the possible differences found. The results suggest that participants with SAD who were submitted to a version without emotional impact had higher rates of real memories, according to attentional bias characteristic of this population. Besides, the participants who suffer from Social Anxiety Disorder (SAD) had higher rates of false memories who were submitted to a version without emotional impact, suggesting that emotion acted as a protection and suggesting that the social anxiety has a significant action over memory performance.
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Encoding contributions to mnemonic discrimination and its age-related declinePidgeon, Laura Marie January 2015 (has links)
Many items encoded into episodic memory are highly similar – seeing a stranger’s car may result in a memory representation which overlaps in many features with the memory of your friend’s car. To avoid falsely recognising the novel but similar car, it is important for the representations to be distinguished in memory. Even in healthy young adults failures of this mnemonic discrimination lead relatively often to false recognition, and such errors become substantially more frequent in older age. Whether an item’s representation is discriminated from similar memory representations depends critically on how it is encoded. However, the precise encoding mechanisms involved remain poorly understood. Establishing the determinants of successful mnemonic discrimination is essential for future research into strategies or interventions to prevent recognition errors, particularly in the context of age-related decline. A fuller understanding of age-related decline in mnemonic discrimination can also inform basic models of memory. This thesis evaluated the contribution of encoding processes to mnemonic discrimination both in young adults and in ageing, within the framework of two prominent accounts of recognition memory, the pattern separation account (Wilson et al., 2006) and Fuzzy Trace Theory (FTT; Brainerd & Reyna, 2002). Firstly, a functional magnetic resonance imaging study in young adults found evidence for differences in regions engaged at encoding of images according to the accuracy of later mnemonic discrimination, consistent with both pattern separation and FTT. Evidence of functional overlap between regions showing activity consistent with pattern separation, and activity associated with later accurate recognition was consistent with a role of cortical pattern separation in successful encoding, but there was no direct evidence that cortical pattern separation contributed to mnemonic discrimination. This first evidence of cortical pattern separation in humans was supported by findings that in the majority of pattern separation regions, response functions to stimuli varied in their similarity to previous items were consistent with predictions of computational models. Regional variation in the dimension(s) of similarity (conceptual/perceptual) driving pattern separation was indicative of variation in the type of mnemonic interference minimised by cortical pattern separation. Further evidence of encoding contributions to mnemonic discrimination was provided by an event-related potential study in young and older adults. Older adults showed less distinct waveforms than young adults at encoding of items whose similar lures were later correctly rejected compared to those falsely recognised, supporting the proposal that age-related encoding impairments contribute to the decline in mnemonic discrimination. Finally, a set of behavioural studies found that older adults’ mnemonic discrimination deficit is increased by conceptual similarity, supporting previous findings and consistent with FTT’s account of greater emphasis by older adults on gist processing. However, older adults required greater reduction in perceptual or conceptual similarity in order to successfully reject lures, as uniquely predicted by the pattern separation account. Together, the findings support the notion that encoding processes contribute directly to mnemonic discrimination and its age-related decline. An integrated view of the pattern separation account and FTT is discussed and developed in relation to the current findings.
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Police Perceptions on False Accusations of Sexual AssaultOstrander, Danielle 01 May 2018 (has links)
The purpose of this study was to expand current literature regarding police officers’ perceptions on false accusations of sexual assault; specifically, focusing on perceptions of the frequency of false accusations, rape myths and behavior displayed by women reporting sexual assault. Police officers’ perceptions on false accusations of sexual assault were examined by administering a 21-question survey consisting of close-ended and open-ended questions. The survey included questions about police perceptions, false accusations, rape myths, training, and behaviors of women reporting sexual assault. The sample consisted of 40 sworn law enforcement officers from different municipal police departments in Tennessee. The results showed that, despite empirical evidence, police officers were more likely to perceive high rates of false accusations of sexual assault, as well as endorse certain rape myths. Findings also showed a number of police officers perceived different behaviors of women making a false report than those not making a false report.
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