480 research outputs found

    Formal Modeling of Connectionism using Concurrency Theory, an Approach Based on Automata and Model Checking

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    This paper illustrates a framework for applying formal methods techniques, which are symbolic in nature, to specifying and verifying neural networks, which are sub-symbolic in nature. The paper describes a communicating automata [Bowman & Gomez, 2006] model of neural networks. We also implement the model using timed automata [Alur & Dill, 1994] and then undertake a verification of these models using the model checker Uppaal [Pettersson, 2000] in order to evaluate the performance of learning algorithms. This paper also presents discussion of a number of broad issues concerning cognitive neuroscience and the debate as to whether symbolic processing or connectionism is a suitable representation of cognitive systems. Additionally, the issue of integrating symbolic techniques, such as formal methods, with complex neural networks is discussed. We then argue that symbolic verifications may give theoretically well-founded ways to evaluate and justify neural learning systems in the field of both theoretical research and real world applications

    An investigation of the myopia for future consequences theory of VMF patient behaviour on the Iowa Gambling Task: An abstract neural network simulation

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    Somatic marker theory proposes that body states act as a valence associated with potential choices based on prior outcomes; and thus aid decision-making. The main supporting evidence for this theory arose from clinical interviews of subjects with ventromedial prefrontal cortex (VMF) lesions and their performance on the Iowa Gambling Task (IGT). VMF patient behaviour has been described as myopia about future consequences. The aim of this paper is to investigate the implications of this description using an abstract simulation of the neural mechanisms that could underlie decision-making in this type of reinforcement learning task

    Rapid presentation rate negatively impacts the contiguity effect in free recall

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    It is well-known that in free recall participants tend to recall words presented close together in time in sequence, reflecting a form of temporal binding in memory. This contiguity effect is robust, having been observed across many different experimental manipulations. In order to explore a potential boundary on the contiguity effect, participants performed a free recall task in which items were presented at rates ranging from 2 Hz to 8 Hz. Participants were still able to recall items even at the fastest presentation rate, though accuracy decreased. Importantly, the contiguity effect flattened as presentation rates increased. These findings illuminate possible constraints on the temporal encoding of episodic memories.http://sites.bu.edu/tcn/files/2019/05/RSVP_FR.pdfAccepted manuscrip

    High School Sophomores\u27 Perceptions of the Role of Extra-Curricular Activities as Preparation for College Admission

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    While there is significant interest and emphasis on student participation in extra-curricular activities, limited research on such participation and the benefits it may possess toward preparing students for college admissions exists. A survey of 312 high school sophomores in a rural, southeastern Louisiana school district was conducted. Data were collected through the survey on the students\u27 participation in extra-curricular activities and their perceived value of such participation toward gaining admission to a postsecondary institution. The purpose of the study was to analyze the relationship between participation in extra-curricular activity and the perceived value of such participation toward gaining admission to college as reported by the students. Additionally, the relationship was further analyzed when controlled for gender, academic performance (GPA), and religious participation. The research found a statistically significant relationship between participation in extra-curricular activities and the perceived value of such participation toward gaining admissions to a postsecondary institution. The research also found the relationship to be statistically significant when controlled for gender, grades, and religious participation. From this study, the researcher concluded that the relationship between participation in extra-curricular activities and the value held of such participation toward obtaining admission to college was evident but did not exhibit a strong relationship. Additionally, when controlled for religious participation, gender, and GPA, there was no effect on the correlation of the two variables. Students valued, however, participation in extra-curricular activities as a component for obtaining admission to a postsecondary institution. Students in this survey agreed that such participation did prepare them for the college admissions process. Particularly, students who participated in extra-curricular activities held a higher value of their participation toward college admission than students who did not participate in extra-curricular activities. Students surveyed did recognize their respective schools\u27 efforts in preparing them for college overall, but indicated their high school rarely acknowledged the relationship between extra-curricular activities and the admissions process into a postsecondary institution. While this particular study produced many more questions than it did answers, the information gained can play a critical role in making decisions regarding extra-curricular activities. School and district administrators should utilize the information in this study for any future decisions made regarding extracurricular activities

    Colorimetric characterization of the Apple studio display (Flat panel LCD)

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    The colorimetric characterization of a flat-panel LCD monitor, the Apple Studio Display, using traditional CRT characterization techniques was evaluated. The results showed that the display performed up to the manufacturer\u27s specifications in terms of luminance and contrast. However, the traditional CRT gain-offset-gamma (GOG) model for characterization was inadequate and a model with one-dimensional lookup tables followed by a 3x3 matrix was developed. The LUT model performed excellently with average CIE94 color differences between measured and predicted colors of approximately 1.0

    Modeling the neural circuitry underlying the behavioral and EEG correlates of attentional capture

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    The Reactive-Convergent Gradient Field model (R-CGF) is a unique approach to modeling spatial attention in that it links neural mechanisms to event related potentials (ERPs) from scalp EEG. This model was developed with the aim of explaining different, sometimes conflicting, findings in the attention literature. Specifically, this model address conflicting findings showing both simultaneous and serial deployment of attention. Another argument addressed by the model is whether attention to a location invokes a suppression of the spatial surround, or the selective inhibition of distractors. With the R-CGF, we have found that these results are not as incompatible as they appear but rather can both result from a common set of mechanisms in different kinds of experiments. The model has three main neural sheets, early vision (EV), late vision (LV) and a master attention map (AM), connected spatiotopically. The LV layers are specialized for different features (e.g. shape or color) with modulated connections to the AM depending on task requirements. The AM implements a reactive inhibitory circuit through gating neurons that suppresses attention selectively at the location of distractors that are proximal to the target

    Thermal conductive connection and method of making same Patent

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    Thermal conductive, electrically insulated cleavable adhesive connection between electronic module and heat sin

    RSVP in orbit: Identification of single and dual targets in motion

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    Three experiments using rapid serial visual presentation (RSVP) tested participants' ability to detect targets in streams that are in motion. These experiments compared the ability to identify moving versus stationary RSVP targets and examined the attentional blink with pairs of targets that were moving or stationary. One condition presented RSVP streams in the center of the screen; a second condition used an RSVP that was orbiting in a circle, with participants instructed to follow the stream with their eyes; and a third condition had participants fixate in the middle while observing a circling RSVP stream. Relative to performance in stationary RSVP streams, participants were not markedly impaired in detecting single targets in RSVP streams that were moving, either with or without instructions to pursue the motion. In streams with two targets, a normal attentional blink effect was observed when participants were instructed to pursue the moving stream. When participants had to maintain central fixation as the RSVP stream moved, the attentional blink was nearly absent even when a trailing mask was added. We suggest that the reduction of the attentional blink for moving RSVP streams may reflect a reduced ability to perceive the temporal boundaries of the individual items

    Reproducibility comparison among multiangle spectrophotometers

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    New color-measuring instruments known as multiangle spectrophotometers have been recently created to measure and characterize the goniochromism of special-effect pigments in many materials with a particular visual appearance (metallic, interference, pearlescent, sparkle, or glitter). These devices measure the gonioapparent color from the spectral relative reflectance factor and the L*a*b* values of the sample with different illumination and observation angles. These angles usually coincide with requirements marked in American Society for Testing and Materials (ASTM) and Deutsches Institut Für Normung standards relating to the gonioapparent color, but the results of comparisons between these instruments are still inconclusive. Therefore, the main purpose of this study is to compare several multiangle spectrophotometers at a reproducibility level according to ASTM E2214-08 guidelines. In particular, we compared two X-Rite multi-gonio spectrophotometers (MA98 and MA68II), a Datacolor multi-gonio spectrophotometer (FX10), and a BYK multi-gonio spectrophotometer (BYK-mac). These instruments share only five common measurement geometries: 45° × −30° (as 15°), 45° × −20° (as 25°), 45° × 0° (as 45°), 45° × 30° (as 75°), 45° × 65° (as 110°). Specific statistical studies were used for the reproducibility comparison, including a Hotelling test and a statistical intercomparison test to determine the confidence interval of the partial color differences ΔL*, Δa*, Δb*, and the total color difference ΔE*ab. This was conducted using a database collection of 88 metallic and pearlescent samples that were measured 20 times without the replacement of all the instruments. The final findings show that in most measurement geometries, the reproducibility differences between pairs of instruments are statistically significant, although in general, there is a better reproducibility level at certain common geometries for newer instruments (MA98 and BYK-mac). This means that these differences are due to systematic or bias errors (angle tolerances for each geometry, photometric scales, white standards, etc.), but not exclusively to random errors. However, neither of the statistical tests used is valid to discriminate and quantify the detected bias errors in this comparison between instruments.Spanish Ministry of Science and Innovation; contract grant number: DPI2008-06455-C02-02
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