Occlusion is most commonly presented as an aspect of certain genres: occluded genres. Here, occlusion is proposed as a property of the processes by which genres are taken up. While routine use of genres creates expectations around when the genre’s uptake is commonly occluded, such expected practice can be subverted by deliberate disclosure. Occlusion and disclosure in the process of genre uptake thus become argumentative and powerful moves in communicative interaction. In three case studies, I analyze processes (...) of occlusion in relationship to the genre of the letter to the university president. (shrink)

This paper examines the evolution of Edmund Husserl’s theory of perceptual occlusion. This task is accomplished in two stages. First, I elucidate Husserl’s conclusion, from his 1901 Logical Investigations, that the occluded parts of perceptual objects are intended by partial signitive acts. I focus on two doctrines of that account. I examine Husserl’s insight that signitive intentions are composed of Gehalt and I discuss his conclusion that signitive intentions sit on the continuum of fullness. Second, the paper discloses how (...) Husserl transforms his 1901 philosophy in his 1913 revisions to the Sixth Logical Investigation, affirming that the occluded parts of perceptual objects are intended by empty contiguity acts. I demonstrate how he overturns the two core doctrines of his theory from the Investigations in these revisions, claiming that empty intentions are not composed of Gehalt and asserting that those acts break with the continuum of fullness. Husserl implements these changes to solve problems that arise from his recognition of two new kinds of intentions; darker and completely dark acts. Finally, in the conclusion, I cash out this analysis, by indicating that, in 1913, Husserl transforms his theory of fulfillment on the basis of his new insights about empty acts. (shrink)

In pedestrian detection, occlusions are typically treated as an unstructured source of noise and explicit models have lagged behind those for object appearance, which will result in degradation of detection performance. In this paper, a hierarchical co-occurrence model is proposed to enhance the semantic representation of a pedestrian. In our proposed hierarchical model, a latent SVM structure is employed to model the spatial co-occurrence relations among the parent–child pairs of nodes as hidden variables for handling the partial occlusions. Moreover, the (...) visibility statuses of the pedestrian can be generated by learning co-occurrence relations from the positive training data with large numbers of synthetically occluded instances. Finally, based on the proposed hierarchical co-occurrence model, a pedestrian detection algorithm is implemented to incorporate visibility statuses by means of a Random Forest ensemble. The experimental results on three public datasets demonstrate the log-average miss rate of the proposed algorithm has 5% improvement for pedestrians with partial occlusions compared with the state-of-the-arts. (shrink)

This paper aims to advance our understanding of Heidegger's politics as it is laid bare within the 'Schwarze Hefte'. Yet my interest is not in Heidegger's first order political views, but rather in his conception of the political sphere per se. Beginning from a close analysis of the earliest volume of the notebooks, Gesamtausgabe Bd.94, I suggest that the dominant characterisation of the political space within Heidegger's text is as a threat-to philosophy and to ontology. Underlying that characterisation, however, it (...) is simultaneously possible to identify another pattern, one on which the political is itself gradually suppressed or occluded by the ontological. This tacit occlusion has, I suggest, a number of deeply problematic consequences. I close by indicating how the argument might be extended to the question of a Heideggerian ethics. (shrink)

We show that early vision can use monocular cues to rapidly complete partially-occluded objects. Visual search for easily detected fragments becomes difficult when the completed shape is similar to others in the display; conversely, search for fragments that are difficult to detect becomes easy when the completed shape is distinctive. Results indicate that completion occurs via the occlusion-triggered removal of occlusion edges and linking of associated regions. We fail to find evidence for a visible filling-in of contours or (...) surfaces, but do find evidence for a "functional" filling-in that prevents the constituent fragments from being rapidly accessed. As such, it is only the completed structures—and not the fragments themselves—that serve as the basis for rapid recognition. (shrink)

In “Neither Ethical nor Prudent: Why Not to Choose Normothermic Regional Perfusion” Omelianchuk and colleagues offer an exceptionally clear and methodical critique of the ethical and legal permissibility of in situ normothermic regional perfusion (NRP). NRP involves, in part, the reperfusion of organs via extracorporeal membrane oxygenation (ECMO) after a declaration of death and the occlusion of the arteries supplying blood to the brain. The authors’ main conclusion is that NRP invalidates the declaration of death via the standards set (...) by the Uniform Determination of Death Act (which requires either permanent cessation of circulatory and respiratory functions or irreversible cessation of all brain functions for a determination of death) and thereby violates the Dead Donor Rule (DDR) (which, minimally, requires that organ recovery not be the cause of death). Their arguments for these points, however, are flawed. Most notably, this conclusion rests on mistaken assumptions about the role of circulation in both the UDDA and DDR. A close examination of the role of circulation in sustaining life shows that NRP is consistent with both the UDDA and the DDR. (shrink)

This paper attempts to answer a central question in unsupervised learning: what does it mean to “make sense” of a sensory sequence? In our formalization, making sense involves constructing a symbolic causal theory that both explains the sensory sequence and also satisfies a set of unity conditions. The unity conditions insist that the constituents of the causal theory – objects, properties, and laws – must be integrated into a coherent whole. On our account, making sense of sensory input is a (...) type of program synthesis, but it is unsupervised program synthesis. Our second contribution is a computer implementation, the Apperception Engine, that was designed to satisfy the above requirements. Our system is able to produce interpretable human-readable causal theories from very small amounts of data, because of the strong inductive bias provided by the unity conditions. A causal theory produced by our system is able to predict future sensor readings, as well as retrodict earlier readings, and impute (fill in the blanks of) missing sensory readings, in any combination. In fact, it is able to do all three tasks simultaneously. We tested the engine in a diverse variety of domains, including cellular automata, rhythms and simple nursery tunes, multi-modal binding problems, occlusion tasks, and sequence induction intelligence tests. In each domain, we test our engine's ability to predict future sensor values, retrodict earlier sensor values, and impute missing sensory data. The Apperception Engine performs well in all these domains, significantly out-performing neural net baselines. We note in particular that in the sequence induction intelligence tests, our system achieved human-level performance. This is notable because our system is not a bespoke system designed specifically to solve intelligence tests, but a general-purpose system that was designed to make sense of any sensory sequence. (shrink)

Vision is organized around material objects; they are most of what we see. But we also see beams of light, depictions, shadows, reflections, etc. These things look like material objects in many ways, but it is still visually obvious that they are not material objects. This chapter articulates some principles that allow us to understand how we see these ‘ephemera’. H.P. Grice’s definition of seeing is standard in many discussions; here I clarify and augment it with a criterion drawn from (...) Fred Dretske. This enables me to re-analyse certain ephemera that have received counter-intuitive treatments in the work of Kendall Walton (photographs), Brian O’Shaughnessy (light), and Roy Sorenson (occlusions). (shrink)

Perceptual neuroscience has identified mechanisms of perceptual grouping which account for the ways in which visual sensitivity to ordered structure and regularities expresses itself, in behavior and in the brain. The need to actively construct order, notably representations of objects in depth, is mandated as soon as visual signals reach the retina, given the occlusion of retinal signals by retinal veins and other retinal elements or blur. Multiple stages of neural processing transform fragmented signals into visual key representations of (...) 3D scenes that can be used to control effective behaviors. Since our survival depends on our ability to pick up order in the physical world, and since we conceive the physical world as an ordered one, our perception must somehow be sensitive to order. The articles from this collection illustrate how texture dissimilarity, boundary completion, surface filling-in, and figure-ground segregation generate perceptual order. (shrink)

Luminance and color are strong and self-sufficient cues to pictorial depth in visual scenes and images. The present study investigates the conditions Under which luminance or color either strengthens or overrides geometric depth cues. We investigated how luminance contrasts associated with color contrast interact with relative height in the visual field, partial occlusion, and interposition in determining the probability that a given figure is perceived as ‘‘nearer’’ than another. Latencies of ‘‘near’’ responses were analyzed to test for effects of (...) attentional selection. Figures in a pair were supported by luminance contrast or isoluminant color contrast and combined with one of the three geometric cues. The results of Experiment 1 show that luminance contrasts associated with hue, when it does not interact with other hues, produces the same effects as achromatic luminance contrasts: The probability of‘‘near’’ increases with luminance contrast while the latencies for ‘‘near’’ responses decrease. Partial occlusion is found to be a strong enough pictorial cue to support a weaker red luminance contrast. Interposition cues lose out against cues of spatial position and partial occlusion. The results of Experiment 2, with isoluminant displays of varying color contrast, reveal that red color contrast on a light background supported by any of the three geometric cues wins over green or white supported by any of the three geometric cues. On a dark background, red color contrast supported by the interposition cue loses out against green or white color contrast supported by partial occlusion. These findings reveal that color is not an independent depth cue, but is strongly influenced by luminance contrast and stimulus geometry. Systematically shorter response latencies for stronger ‘‘near’’ percepts demonstrate that selective visual attention reliably detects the most likely depth cue combination in a given configuration. (shrink)

The experiments reported herein probe the visual cortical mechanisms that control near–far percepts in response to two-dimensional stimuli. Figural contrast is found to be a principal factor for the emergence of percepts of near versus far in pictorial stimuli, especially when stimulus duration is brief. Pictorial factors such as interposition (Experiment 1) and partial occlusion Experiments 2 and 3) may cooperate, as generally predicted by cue combination models, or compete with contrast factors in the manner predicted by the FACADE (...) model. In particular, if the geometrical conŽ guration of an image favors activation of cortical bipole grouping cells, as at the top of a T-junction, then this advantage can cooperate with the contrast of the conŽ guration to facilitate a near–far percept at a lower contrast than at an X-junction. Varying the exposure duration of the stimuli shows that the more balanced bipole competition in the X-junction case takes longer exposure times to resolve than the bipole competition in the T-junction case (Experiment 3). (shrink)

Abstract: Sickle cell disease (SCD) comprises an inherited blood disorder that is life long and affects many people globally. Despite progress in therapy, SCA is a considerable cause of mortality and morbidity. This study was designed to measure the immunological and inflammatory parameters of patients with sickle cell disease (SCD) and to found if there is any role of it in the pathogenicity of the disease. This study included A total of 32 patients, their ages ranged from 16 to 55 (...) years patients with Sickle cell disease who have been evaluated during vaso occlusive crisis and had been followed up till they attained steady state, and there are 32 normal control subjects matched with patients in age and sex. In general there was elevation in all parameters the study were included in patients than control and particularly in crisis, despite the IgM value which was insignificantly decrease, but the statically significant elevation reported only in CRP, IgG, IgA. (shrink)

This paper examines the evolution of Husserl’s philosophy of nonintuitive intentions. The analysis has two stages. First, I expose a mistake in Husserl’s account of non-intuitive acts from his 1901 Logical Investigations. I demonstrate that Husserl employs the term “signitive” too broadly, as he concludes that all non-intuitive acts are signitive. He states that not only meaning acts, but also the contiguity intentions of perception are signitive acts. Second, I show how Husserl, in his 1913/14 Revisions to the Sixth Logical (...) Investigation, amends his 1901 theory of non-intuitive acts, which he now calls “empty” intentions. He there accurately distinguishes empty meaning acts from the empty intentions of perception. In the conclusion, I reveal how Husserl’s alterations to his theory of non-intuitive intentions can inform our understanding of a larger shift in his philosophy. (shrink)

The problem of amodal perception is the problem of how we represent features of perceived objects that are occluded or otherwise hidden from us. Bence Nanay (2010) has recently proposed that we amodally perceive an object's occluded features by imaginatively projecting them into the relevant regions of visual egocentric space. In this paper, I argue that amodal perception is not a single, unitary capacity. Drawing appropriate distinctions reveals amodal perception to be characterized not only by mental imagery, as Nanay suggests, (...) but also by genuinely visual representations as well as beliefs. I conclude with some brief remarks on the role of object-directed bodily action in conferring a sense of unseen presence on an object's occluded features. (shrink)