Ensemble of a subset of kNN classifiers

Combining multiple classifiers, known as ensemble methods, can give substantial improvement in prediction performance of learning algorithms especially in the presence of non-informative features in the data sets. We propose an ensemble of subset of kNN classifiers, ESkNN, for classification task in two steps. Firstly, we choose classifiers based upon their individual performance using the out-of-sample accuracy. The selected classifiers are then combined sequentially starting from the best model and assessed for collective performance on a validation data set. We use bench mark data sets with their original and some added non-informative features for the evaluation of our method. The results are compared with usual kNN, bagged kNN, random kNN, multiple feature subset method, random forest and support vector machines. Our experimental comparisons on benchmark classification problems and simulated data sets reveal that the proposed ensemble gives better classification performance than the usual kNN and its ensembles, and performs comparable to random forest and support vector machines

Do Characteristics of Faces That Convey Trustworthiness and Dominance Underlie Perceptions of Criminality?

BACKGROUND: This study tested whether the 2D face evaluation model proposed by Oosterhof and Todorov can parsimoniously account for why some faces are perceived as more criminal-looking than others. The 2D model proposes that trust and dominance are spontaneously evaluated from features of faces. These evaluations have adaptive significance from an evolutionary standpoint because they indicate whether someone should be approached or avoided. METHOD: Participants rated the emotional state, personality traits, and criminal appearance of faces shown in photographs. The photographs were of males and females taken under naturalistic conditions (i.e., police mugshots) and highly controlled conditions. In the controlled photographs, the emotion display of the actor was systematically varied (happy expression, emotionally neutral expression, or angry expression). RESULTS: Both male and female faces rated high in criminal appearance were perceived as less trustworthy and more dominant in police mugshots as well as in photographs taken under highly controlled conditions. Additionally, emotionally neutral faces were deemed as less trustworthy if they were perceived as angry, and more dominant if they were morphologically mature. Systematically varying emotion displays also affected criminality ratings, with angry faces perceived as the most criminal, followed by neutral faces and then happy faces. CONCLUSION: The 2D model parsimoniously accounts for criminality perceptions. This study extends past research by demonstrating that morphological features that signal high dominance and low trustworthiness can also signal high criminality. Spontaneous evaluations regarding criminal propensity may have adaptive value in that they may help us to avoid someone who is physically threatening. On the other hand, such evaluations could inappropriately influence decision making in criminal identification lineups. Hence, additional research is needed to discover whether and how people can avoid making evaluations regarding criminality from a person's facial appearance

Spaceborne Photonics Institute

This report describes in chronological detail the development of the Spaceborne Photonics Institute as a sustained research effort at Hampton University in the area of optical physics. This provided the research expertise to initiate a PhD program in Physics. Research was carried out in the areas of: (1) modelling of spaceborne solid state laser systems; (2) amplified spontaneous emission in solar pumped iodine lasers; (3) closely simulated AM0 CW solar pumped iodine laser and repeatedly short pulsed iodine laser oscillator; (4) a materials spectroscopy and growth program; and (5) laser induced fluorescence and atomic and molecular spectroscopy

On the Perception of Religious Group Membership from Faces

BACKGROUND: The study of social categorization has largely been confined to examining groups distinguished by perceptually obvious cues. Yet many ecologically important group distinctions are less clear, permitting insights into the general processes involved in person perception. Although religious group membership is thought to be perceptually ambiguous, folk beliefs suggest that Mormons and non-Mormons can be categorized from their appearance. We tested whether Mormons could be distinguished from non-Mormons and investigated the basis for this effect to gain insight to how subtle perceptual cues can support complex social categorizations. METHODOLOGY/PRINCIPAL FINDINGS: Participants categorized Mormons' and non-Mormons' faces or facial features according to their group membership. Individuals could distinguish between the two groups significantly better than chance guessing from their full faces and faces without hair, with eyes and mouth covered, without outer face shape, and inverted 180°; but not from isolated features (i.e., eyes, nose, or mouth). Perceivers' estimations of their accuracy did not match their actual accuracy. Exploration of the remaining features showed that Mormons and non-Mormons significantly differed in perceived health and that these perceptions were related to perceptions of skin quality, as demonstrated in a structural equation model representing the contributions of skin color and skin texture. Other judgments related to health (facial attractiveness, facial symmetry, and structural aspects related to body weight) did not differ between the two groups. Perceptions of health were also responsible for differences in perceived spirituality, explaining folk hypotheses that Mormons are distinct because they appear more spiritual than non-Mormons. CONCLUSIONS/SIGNIFICANCE: Subtle markers of group membership can influence how others are perceived and categorized. Perceptions of health from non-obvious and minimal cues distinguished individuals according to their religious group membership. These data illustrate how the non-conscious detection of very subtle differences in others' appearances supports cognitively complex judgments such as social categorization

Non-crosslinked porcine-derived acellular dermal matrix for the management of complex ventral abdominal wall hernias: a report of 45 cases

PURPOSE: Ventral abdominal wall hernias are common and repair is frequently associated with complications and recurrence. Although non-crosslinked intact porcine-derived acellular dermal matrix (PADM) has been used successfully in the repair of complex ventral hernias, there is currently no consensus regarding the type of mesh and surgical techniques to use in these patients. This report provides added support for PADM use in complex ventral hernias. METHODS: In a consecutive series of adult patients (2008–2011), complex ventral abdominal wall hernias (primary and incisional) were repaired with PADM by a single surgeon. Patient comorbidities, repair procedures, and postoperative recovery, recurrence, and complications were noted. RESULTS: Forty-four patients (mean age, 57.5 years) underwent 45 single-stage ventral abdominal wall hernia repairs (3 primary; 42 incisional). Previously placed synthetic mesh was removed in 17 cases. In 40 cases, primary fascial closure was achieved; in 5 cases, PADM was used as a bridge. Vacuum-assisted closure (VAC) was used for 38/45 cases: 19 closed incisions, 16 cases using the “French fry” technique, and 3 cases with open incisions. Mean hospital stay was 8.2 days (range, 3–32) and mean follow-up was 17 months (range, 1–48). There were 4 (8.9 %) hernia recurrences, 3 requiring additional repair and 1 requiring PADM explantation. There were 3 (6.7 %) skin dehiscences, 4 (8.9 %) deep wound infections requiring drainage, and 5 (11.1 %) seromas (4 self-limited, 1 requiring drainage). CONCLUSIONS: Non-crosslinked intact PADM yielded favorable early outcomes when used to repair complex ventral abdominal wall hernias in high-risk patients. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s10029-013-1148-x) contains supplementary material, which is available to authorized users