Are You Tampering With My Data?

We propose a novel approach towards adversarial attacks on neural networks (NN), focusing on tampering the data used for training instead of generating attacks on trained models. Our network-agnostic method creates a backdoor during training which can be exploited at test time to force a neural network to exhibit abnormal behaviour. We demonstrate on two widely used datasets (CIFAR-10 and SVHN) that a universal modification of just one pixel per image for all the images of a class in the training set is enough to corrupt the training procedure of several state-of-the-art deep neural networks causing the networks to misclassify any images to which the modification is applied. Our aim is to bring to the attention of the machine learning community, the possibility that even learning-based methods that are personally trained on public datasets can be subject to attacks by a skillful adversary.Comment: 18 page

A National Study on the Physical and Mental Health of Intersex Adults in the U.S.

Objectives: To describe the health of intersex adults (people with differences of sex development) in the U.S. using community-based research methods. Methods: In July–September 2018, we conducted a national health study of intersex adults aged 18 and older in the U.S., using a survey hosted on Qualtrics. The study describes the physical and mental health experiences of intersex adults, including differences by age (18 to 39 vs. 40 and older). Questions were derived from national (Behavioral Risk Factor Surveillance System) and intersex-related health studies. Results: A non-probability sample of 198 intersex adults completed the survey over three months. Over 43% of participants rated their physical health as fair/poor and 53% reported fair/poor mental health. Prevalent health diagnoses included depression, anxiety, arthritis, and hypertension, with significant differences by age. Nearly a third reported difficulty with everyday tasks and over half reported serious difficulties with cognitive tasks. Conclusions: To our knowledge, this is the first national study of intersex adults in the U.S. Greater understanding of intersex health over the life course is essential. Findings highlight the need for longitudinal studies and further examination of potential health disparities experienced by intersex populations

Three color strategies in architectural composition

This is the pre-peer reviewed version of the following article: Serra, J. (2013), Three color strategies in architectural composition. Color Res. Appl., 38: 238–250. doi: 10.1002/col.21717, which has been published in final form at http://onlinelibrary.wiley.com/doi/10.1002/col.21717/abstractThis article deals with the possibilities that color affords architectural composition, the strategies facilitated through color as a vocabulary of expression. It primarily focuses on the rules of grammar and syntax of color, and to a lesser degree on the semantic meanings, as this would entail multiple interpretations by the observer. Following an analysis of architectural color classification systems suggested by other authors, we reason that there are three main groups of plastic strategies. These are not mutually exclusive, but rather, complementary to each other: (I) color can influence the perception of the visual properties of architectural shapes; (II) color can describe the building and (III) color can be arranged for its intrinsic value. Each of these strategies deals with a different level of knowledge of the building, which requires both subconscious and conscious mechanisms of identification by the observer. These are the color strategies used by architects to express a particular compositional purpose. © 2012 Wiley Periodicals, Inc.Serra Lluch, J. (2013). Three color strategies in architectural composition. Color Research and Application. 38(4):238-250. https://doi.org/10.1002/col.21717S238250384Arnoldi, P. (2007). Colour is Communication. doi:10.1007/978-3-7643-8202-5Fridell Anter K 2004 227 230Arrarte Grau M 2008 53 54http://www.mvrdv.nl/#/news/074studiothonikIttelson, W. H., & Kilpatrick, F. P. (1951). Experiments in Perception. Scientific American, 185(2), 50-55. doi:10.1038/scientificamerican0851-50Bottoni P 1927Humphrey N The effect of color on our perception of space Porter T Mikellides B London Studio Vista 1976 98 99Caivano JL Menghi I Iadisernia N 2004 113 115Humphrey N The color currency of nature Porter T Mikellides B London Studio Vista 1976 98 99Serra J Gilabert S Torres A Llopis J García A 2010 178 18

Dynamic accommodation without feedback does not respond to isolated blur cues.

The aim of this study was to determine whether dynamic accommodation responds to isolated blur cues without feedback, and without changes in the distance of the object. Nine healthy subjects aged 21-40years were recruited. Four different aberration patterns were used as stimuli to induce blur with (1) the eye's natural, uncorrected, optical aberrations, (2) all aberrations corrected, (3) spherical aberration only, or (4) astigmatism only. The stimulus was a video animation based on computer-generated images of a monochromatic Maltese cross. Each individual video was generated for each subject off-line, after measuring individual aberrations at different accommodation levels. The video simulated sinusoidal changes in defocus at 0.2Hz. Dynamic images were observed through a 0.8mm pinhole placed at a plane conjugated with the eye's pupil, thus effectively removing potential feedback stemming from accommodation changes. Accommodation responses were measured with a Hartmann-Shack aberrometer for the four different aberration patterns. The results showed that seven out of nine subjects did not respond to any stimuli, whereas the response of the other two subjects was erratic and they seemed to be searching rather than following the stimulus. A significant reduction in average accommodative gain (from 0.52 to 0.11) was obtained when the dioptric demand cue was removed. No statistically significant differences were found among the experimental conditions used. We conclude that aberration related blur does not drive the accommodation response in the absence of feedback from accommodation

There is more to accommodation of the eye than simply minimizing retinal blur.

Eyes of children and young adults change their optical power to focus nearby objects at the retina. But does accommodation function by trial and error to minimize blur and maximize contrast as is generally accepted? Three experiments in monocular and monochromatic vision were performed under two conditions while aberrations were being corrected. In the first condition, feedback was available to the eye from both optical vergence and optical blur. In the second, feedback was only available from target blur. Accommodation was less precise for the second condition, suggesting that it is more than a trial-and-error function. Optical vergence itself seems to be an important cue for accommodation

Engrained experience—a comparison of microclimate perception schemata and microclimate measurements in Dutch urban squares

Acceptance of public spaces is often guided by perceptual schemata. Such schemata also seem to play a role in thermal comfort and microclimate experience. For climate-responsive design with a focus on thermal comfort it is important to acquire knowledge about these schemata. For this purpose, perceived and “real” microclimate situations were compared for three Dutch urban squares. People were asked about their long-term microclimate perceptions, which resulted in “cognitive microclimate maps”. These were compared with mapped microclimate data from measurements representing the common microclimate when people stay outdoors. The comparison revealed some unexpected low matches; people clearly overestimated the influence of the wind. Therefore, a second assumption was developed: that it is the more salient wind situations that become engrained in people’s memory. A comparison using measurement data from windy days shows better matches. This suggests that these more salient situations play a role in the microclimate schemata that people develop about urban places. The consequences from this study for urban design are twofold. Firstly, urban design should address not only the “real” problems, but, more prominently, the “perceived” problems. Secondly, microclimate simulations addressing thermal comfort issues in urban spaces should focus on these perceived, salient situations

How Haptic Size Sensations Improve Distance Perception

Determining distances to objects is one of the most ubiquitous perceptual tasks in everyday life. Nevertheless, it is challenging because the information from a single image confounds object size and distance. Though our brains frequently judge distances accurately, the underlying computations employed by the brain are not well understood. Our work illuminates these computions by formulating a family of probabilistic models that encompass a variety of distinct hypotheses about distance and size perception. We compare these models' predictions to a set of human distance judgments in an interception experiment and use Bayesian analysis tools to quantitatively select the best hypothesis on the basis of its explanatory power and robustness over experimental data. The central question is: whether, and how, human distance perception incorporates size cues to improve accuracy. Our conclusions are: 1) humans incorporate haptic object size sensations for distance perception, 2) the incorporation of haptic sensations is suboptimal given their reliability, 3) humans use environmentally accurate size and distance priors, 4) distance judgments are produced by perceptual “posterior sampling”. In addition, we compared our model's estimated sensory and motor noise parameters with previously reported measurements in the perceptual literature and found good correspondence between them. Taken together, these results represent a major step forward in establishing the computational underpinnings of human distance perception and the role of size information.National Institutes of Health (U.S.) (NIH grant R01EY015261)University of Minnesota (UMN Graduate School Fellowship)National Science Foundation (U.S.) (Graduate Research Fellowship)University of Minnesota (UMN Doctoral Dissertation Fellowship)National Institutes of Health (U.S.) (NIH NRSA grant F32EY019228-02)Ruth L. Kirschstein National Research Service Awar

Testing an integrated destination image model across residents and tourists

Tourism research has yet to confirm whether an integrated destination image model is applicable in predicting the overall destination image and behavioral intentions of local residents. This study examines whether the cognitive, affective and overall image - hypothesized to be predictors of behavioral intentions - are applicable to residents and tourists in the resort city of Eilat. The proposed model allowed for the distinct effect of each image component on overall image and behavior to be closely examined. The findings support the applicability of the model to local residents and also showed that among tourists, the affective component exerted a greater influence than the cognitive on overall destination image and future behavior. These findings have theoretical and practical implications for research on destination image