Search results for: Yanwen Wu

Authors: Yanwen Li, Shuguo Xie

Abstract:

In electromagnetic imaging, because of the diffraction limited system, the pixel values could change slowly near the edge of the image targets and they also change with the location in the same target. Using traditional digital image segmentation methods to segment electromagnetic gradient images could result in lots of errors because of this change in pixel values. To address this issue, this paper proposes a novel image segmentation and extraction algorithm based on Mean-Shift and dictionary learning. Firstly, the preliminary segmentation results from adaptive bandwidth Mean-Shift algorithm are expanded, merged and extracted. Then the overlap rate of the extracted image block is detected before determining a segmentation region with a single complete target. Last, the gradient edge of the extracted targets is recovered and reconstructed by using a dictionary-learning algorithm, while the final segmentation results are obtained which are very close to the gradient target in the original image. Both the experimental results and the simulated results show that the segmentation results are very accurate. The Dice coefficients are improved by 70% to 80% compared with the Mean-Shift only method.

Keywords: gradient image, segmentation and extract, mean-shift algorithm, dictionary iearning

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Authors: Yanwen Wu

Abstract:

Counterfactual reasoning involves reasoning about what might have happened following changes to past events or states. This ability helps people learn lessons from past experiences to draw blueprints for the future. To understand the cognitive underpinnings of this important cognitive skill, it is helpful to investigate what cognitive abilities are associated with counterfactual reasoning. In Chinese, there are no subjunctive forms for directly marking counterfactual thoughts. Additive (introducing new elements to the past) and subtractive (removing existing elements from the past) premises contain different cues for inferring counterfactuality. Hence, interpreting and reasoning from additive and subtractive counterfactual premises might involve different cognitive processes. This study compared the developmental correlates of additive and subtractive counterfactual reasoning in Chinese-speaking children as an under-researched population. The study sample was 147 4- to 6-year-olds (M = 67.53 months, SD = 7.41 months, 70 females and 77 males). All children were Mandarin native speakers from middle-class families. None had developmental disorders, according to the class teacher's report. All children received a task with counterbalanced additive and subtractive counterfactual questions. They also received tasks assessing verbal short-term memory, response inhibition, and receptive vocabulary. Generalized estimating equations tested whether counterfactual reasoning, in general, was associated with other cognitive abilities and whether a logical structure (additive/subtractive) interacted with cognitive abilities in predicting counterfactual reasoning. The results showed that counterfactual reasoning, regardless of logical structures, was significantly associated with response inhibition. Also, there was a marginally significant logical structure × verbal short-term memory interaction. Verbal short-term memory was significantly associated with subtractive counterfactual reasoning. In contrast, it was not significantly associated with additive counterfactual reasoning. The findings suggested that counterfactual reasoning might involve deliberate control of automatic responses. Also, relative to additive counterfactual reasoning, verbal short-term memory might be more important for subtractive counterfactual reasoning. This might be because there are more semantic cues for inferring counterfactuality in subtractive than additive counterfactual premises in Chinese. Future studies may test whether the findings are specific to Chinese or general across languages. They help understand how children in different linguistic environments engage in different types of counterfactual reasoning.

Keywords: Chinese language, counterfactual reasoning, response inhibition, verbal short-term memory

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