Cannon–Thurston maps for $${{\,\mathrm{CAT}\,}}(0)$$ groups with isolated flats

Mahan Mitra (Mj) proved Cannon–Thurston maps exist for normal hyperbolic subgroups of a hyperbolic group (Mitra in Topology, 37(3):527–538, 1998). We prove that Cannon–Thurston maps do not exist for infinite normal hyperbolic subgroups of non-hyperbolic $${{\,\mathrm{CAT}\,}}(0)$$ CAT ( 0 ) groups with isolated flats with respect to the visual boundaries. We also show Cannon–Thurston maps do not exist for infinite infinite-index normal $${{\,\mathrm{CAT}\,}}(0)$$ CAT ( 0 ) subgroups with isolated flats in non-hyperbolic $${{\,\mathrm{CAT}\,}}(0)$$ CAT ( 0 ) groups with isolated flats. We obtain a structure theorem for the normal subgroups in these settings and show that outer automorphism groups of hyperbolic groups have no purely atoroidal $$\mathbb {Z}^2$$ Z 2 subgroups.

Boundary Knowledge Translation based Reference Semantic Segmentation

Given a reference object of an unknown type in an image, human observers can effortlessly find the objects of the same category in another image and precisely tell their visual boundaries. Such visual cognition capability of humans seems absent from the current research spectrum of computer vision. Existing segmentation networks, for example, rely on a humongous amount of labeled data, which is laborious and costly to collect and annotate; besides, the performance of segmentation networks tend to downgrade as the number of the category increases. In this paper, we introduce a novel Reference semantic segmentation Network (Ref-Net) to conduct visual boundary knowledge translation. Ref-Net contains a Reference Segmentation Module (RSM) and a Boundary Knowledge Translation Module (BKTM). Inspired by the human recognition mechanism, RSM is devised only to segment the same category objects based on the features of the reference objects. BKTM, on the other hand, introduces two boundary discriminator branches to conduct inner and outer boundary segmentation of the target object in an adversarial manner, and translate the annotated boundary knowledge of open-source datasets into the segmentation network. Exhaustive experiments demonstrate that, with tens of finely-grained annotated samples as guidance, Ref-Net achieves results on par with fully supervised methods on six datasets. Our code can be found in the supplementary material.

Conscious Seeing and Invariant Recognition

This chapter explains fundamental differences between seeing and recognition, notably how and why our brains use conscious seeing to control actions like looking and reaching, while we learn both view-, size-, and view-specific object recognition categories, and view-, size-, and position-invariant object recognition categories, as our eyes search a scene during active vision. The dorsal Where cortical stream and the ventral What cortical stream interact to regulate invariant category learning by solving the View-to-Object Binding problem whereby inferotemporal, or IT, cortex associates only views of a single object with its learned invariant category. Feature-category resonances between V2/V4 and IT support category recognition. Symptoms of visual agnosia emerge when IT is lesioned. V2 and V4 interact to enable amodal completion of partially occluded objects behind their occluders, without requiring that all occluders look transparent. V4 represents the unoccluded surfaces of opaque objects and triggers a surface-shroud resonance with posterial parietal cortex, or PPC, that renders surfaces consciously visible, and enables them to control actions. Clinical symptoms of visual neglect emerge when PPC is lesioned. A unified explanation is given of data about visual crowding, situational awareness, change blindness, motion-induced blindness, visual search, perceptual stability, and target swapping. Although visual boundaries and surfaces obey computationally complementary laws, feedback between boundaries and surfaces ensure their consistency and initiate figure-ground separation, while commanding our eyes to foveate sequences of salient features on object surfaces, and thereby triggering invariant category learning. What-to-Where stream interactions enable Where’s Waldo searches for desired objects in cluttered scenes.

Overview

An overview is provided of multiple book themes. A critical one is explaining how and where conscious states of seeing, hearing, feeling, and knowing arise in our minds, why they are needed to choose effective actions, yet how unconscious states also critically influence behavior. Other themes include learning, expectation, attention, imagination, and creativity; differences between illusion and reality, and between conscious seeing and recognizing, as embodied within surface-shroud resonances and feature-category resonances, respectively; roles of visual boundaries and surfaces in understanding visual art, movies, and TV; different legacies of Helmholtz and Kanizsa towards understanding vision; how stable opaque percepts and bistable transparent percepts are explained by the same laws; how solving the stability-plasticity dilemma enables brains to learn quickly without catastrophically forgetting previously learned but still useful knowledge; how we correct errors, explore novel experiences, and develop individual selves and cumulative cultural accomplishments; how expected vs. unexpected events are regulated by interacting top-down and bottom-up processes, leading to either adaptive resonances that support fast and stable new learning, or hypothesis testing whereby to learn about novel experiences; how variations of the same cooperative and competitive processes shape intelligence in species, cellular tissues, economic markets, and political systems; how short-term memory, medium-term memory, and long-term memory regulate adaptation to changing environments on different time scales; how processes whereby we learn what events are causal also support irrational, superstitious, obsessional, self-punitive, and antisocial behaviors; how relaxation responses arise; and how future acoustic contexts can disambiguate conscious percepts of past auditory and speech sequences that are occluded by noise or multiple speakers.

Architectural Filth and the Heroic Passivism of Farhadi's Salesman

Architecture in Asghar Farhadi’s The Salesman (2016) is not a mere passive backdrop to an otherwise unaffected narrative; it is an autonomous agent that takes part in the events that unfold, complicates the narrative, and even occasionally defies the ideological position of the film. By analysing interior spaces, architectural elements, urban infrastructure, and maintenance practices, I suggest that 1) the fluid visual boundaries of Farhadi’s spatial settings are instrumental in blurring the borders of truth and morality—themes that are central to his film; 2) the ontological study of architecture, from the moment of excavation to its ultimate fracture/failure serves as a pathological medium to study the troubled masculinity of contemporary Iranian society; 3) spatial infrastructure, as the materialised memory of the film’s determinism, prophetically hints at the inevitable tragedy that awaits. The architectural analysis of The Salesman empowers the audience with additional tools to reflect upon questions of masculinity and determinism. Architecture-as-a-reflection personifies the social filth that cannot be decontaminated through vain beautification strategies. Architecture-as-a-stage reflects the temporality of space and its incidental existence vis-à-vis the dominating presence of infrastructural facilities. Architecture-as-a-confinement embodies the oppressive nature of a society in which restriction, surveillance, and control are imposed upon its residents.

Innovating through Design

During the American hardcover revolution, in the 1980s and 1990s, Alfred A. Knopf established itself as the leading publishing house in book design. Founded in New York in 1915, Knopf has been the recipient of many literary prizes and in 1999 was awarded the American Institute of Graphic Arts (AIGA) Corporate Leadership Award, a prize that recognizes forward-thinking organizations that have been instrumental in the advancement of design by applying the highest standards. Knopf made a name for itself using quality in design along with quality in writing as a strategy for its long-lasting success. One of the main people responsible for this success has been the graphic designer Chip Kidd, one of the most renowed American book cover designers alive. Kidd started working at Knopf in 1986 and soon became the go-to designer for well-known writers such as Michael Crichton, Haruki Murakami, and James Ellroy. His work shows an intuitive understanding of the narrative and a unique and deep connection between text and paratext. Kidd stretches the visual boundaries between words and visuals, asking readers to bridge the gap between what they read and what they see. His covers leave the image open to interpretation; this deliberate lack of definition engages contemporary readers more than traditional covers do. This article illustrates, through the analysis of a selection of the most significant covers designed by Kidd, how his work at Knopf helped create a revolution and shape a new visual language in American book design.

How Looking While Listening Affects Speech Segmentation

This study looks at the mechanisms behind how people learn words of a new language. Syllables that occur within words have a higher chance of occurring together than the syllables between words. Both infants and adults use these transitional probabilities to extract the words in language. However, previous research has examined speech segmentation when learners are presented just with speech. In natural context, we look while we listen and what we see is correlated with what we hear. The goal of my study was to explore how visual context affects adult speech segmentation. To do so, we have three conditions: one where adults were presented with only a word stream, one where while listening adults saw animations that corresponded to words they heard, and one where the animations that the adults saw did not correspond to the words they heard. One hypothesis is that participants in the audio-visual conditions perform better at the segmentation task because the statistical boundaries in the audio are reinforced by the visual boundaries between animations. However, it is also possible that the visual information impairs performance because learners engage in learning the meanings of words in addition to speech segmentation. Preliminary results support the latter hypothesis.