Worcester Polytechnic Institute

About: Worcester Polytechnic Institute is a education organization based out in Worcester, Massachusetts, United States. It is known for research contribution in the topics: Population & Data envelopment analysis. The organization has 6270 authors who have published 12704 publications receiving 332081 citations. The organization is also known as: WPI.

Multiple Bad Data Detectability and Identifiability: A Geometric Approach

Abstract: A method for detecting and identifying multiple bad data in electric power networks is developed by providing a geometric interpretation of the familiar normalized residuals test for single bad data. This generalized multiple bad data test amounts to determining whether the residual vector lies in a subspace determined by the suspect measurements and whether any portions of that subspace are orthogonal to the residual vector. These tests can be performed efficiently using appropriate projection matrices. Thne notion of critical measurement (removal renders the network unobservable) is extended to critical k-tuples of measurements to determine which bad data hypotheses are actually testable. For example, gross errors in critical measurements are not detectable, and gross errors in a critical pair of measurements are detectable but not identifiable. More generally, k-2 gross errors in a critical k-tuple of measurements are identifiable while k or k-l gross errors are detectable but not identifiable. In essence, the set of testable hypotheses is determined by the geometry of the space spanned by all possible residual vectors. A procedure for selecting and pruning a suspect set of measurements is described. Examples for the IEEE 14 bus network are provided.

Scattering of Light from a Rotating Ground Glass

Abstract: We report some experimental results concerning the statistical properties of a light beam scattered by a rotating ground glass with average-size inhomogeneities of approximately 1 μm. Photocount statistics measured at different scattering angles and for different angular velocities of the ground glass have confirmed the known result that the scattered-light amplitude is a stochastic gaussian variable. The Bose–Einstein nature of the photocount statistics has been verified with an accuracy of a few parts per thousand. Self-beating measurements on the scattered light of a He–Ne laser in a TEM00 configuration have shown that the power spectrum is a gaussian function of the frequency. The dependence of its half-width on the angular velocity of the ground glass and on the focal length of the lens that focuses the beam on the scattering surface has been measured. The experimental results agree very closely with our theoretical predictions.

Grappling with Smart City Politics in an Era of Market Triumphalism

Abstract: New ‘sustainable’ urban imaginaries are increasingly taking root in cities and regions around the world. Some notable representative examples of these include: new urbanism (Calthorpe, 1993), compact urban development (Urban Task Force, 2005) and smart growth (Flint, 2006). Proponents of these approaches argue that they are ostensibly built around a new consensus between the planning organisations at various scales, private developers, environmentalists and other relevant non-governmental interests, such as affordable housing advocates. In some sense, then, it might plausibly be argued that these new urban imaginaries transcend the parochial interests that ordinarily punctuate traditional urban and regional politics. Why might this be the case? Proponents of these imaginaries would contend that it is partly due to the fact that smart growth and new urbanist developments are designed to incorporate the tripartite vision of urban sustainability—economic prosperity, ecological integrity and social equity. Moreover, these approaches not only rely on grand visions of future urban utopias; they also incorporate the rhetoric of ‘practical’ visions and plain ‘common sense’ language, in the process broadening their appeal to contemporary policy agendas across the global landscape. And yet at the same time as governments, planners, environmentalists and private interests are actively calling for these new urban development imaginaries— which can be viewed to encourage a revitalised role for more comprehensive and ‘collaborative’ planning—a discourse of market triumphalism has been continuing to sweep its way through different spatial scales of government. States—local, regional and national—seem to be rolling back their own authority and rolling out market-based approaches to urban development—what (Peck, 2004) has referred to as ‘stateauthored market fundamentalism’. Some of the most notable impacts of this neoliberal

Wearable soft robotic device for post-stroke shoulder rehabilitation: Identifying misalignments

Abstract: Stroke is the leading cause of long-term disability in the United States, affecting over 795,000 people annually. In order to regain motor function of the upper body, patients are usually treated by regular sessions with a dedicated physical therapist. A cost-effective wearable upper body orthotics system that can be used at home to empower both the patients and physical therapists is described. The system is composed of a thin, compliant, lightweight, cost-effective soft orthotic device with an integrated cable actuation system that is worn over the upper body, an embedded limb position sensing system, an electric actuator package and controller. The proposed device is robust to misalignments that may occur during actuation of the compliant brace or when putting on the system. Through simulations and experimental evaluation, it was demonstrated i) that the soft orthotic cable-driven shoulder brace can be successfully actuated without the production of off-axis torques in the presence of misalignments and ii) that the proposed model can identify linear and angular misalignments online.

Activation of neural pathways associated with sexual arousal in non‐human primates

Abstract: ODORS ARE IMPORTANT in modulating sexual behavior in a variety of species. However, few studies have connected the behavioral response and the brain activation to the odor stimulation. Attractiveness of a female can be transmitted by chemosensory, visual, and auditory cues; ensuring an increase in male sexual behaviors at a time when females are most fertile (1). Chemical or olfactory cues derived from female scent secretions are known to provide cues of the female’s reproductive status and are important in mediating male sexual behavior in marmosets and tamarins (family Callitrichidae) (2). In response, males have increased sexual behaviors such as tongue-flicks, mounts, and ejaculation (3). While male common marmosets respond with sexual behavior to other sensory cues from female marmosets, such as visual, olfactory cues are important for coordinating male sexual activity with female endocrine status (1). Additionally, scent odors from periovulatory marmoset females are preferred over luteal phase scents from the same female (4). Lesions of the medial preoptic area/anterior hypothalamic continuum (MPOA/AH) have been shown to produce deficiencies in male sexual behavior (5) with decreases in precopulatory and copulatory behaviors, mounting, and anogenital investigation of females. The preoptic area of the hypothalamus has input from the olfactory and vomeronasal systems as well as other sensory systems and induces the release of hormones. Using functional magnetic resonance imaging (fMRI), we corroborated the work of Lloyd and Dixson (5) in demonstrating activation of the MPOA/AH (6). Awake male marmosets presented with the scent marks of unfamiliar females showed enhanced signal intensity in the MPOA/AH to the ovulatory scent versus the ovariectomized (OVX) scent. Although both odors elicited activation versus vehicle control, there was greater activation for the ovulatory scent in the awake males. This imaging study provided evidence that olfactory signals activate the MPOA/AH sexual arousal system in the male common marmoset. Brain imaging has many advantages over lesion studies. Awake male marmosets can be imaged repeatedly and remain intact. In addition to examining functionality of specific brain areas, the entire brain can be imaged to provide information on the integration of arousal and inhibitory processes of the brain in responding to sexually relevant cues. Other neural systems interacting with sexual behavior can be imaged to examine positive affect areas of the brain as well as inhibitory processes. Scent detection is a good starting point for examining brain activity since odor cues elicit distinct behavioral actions. Marmosets, as in all callitrichidae species, show distinct hormonal and behavioral responses to relevant chemical sensory cues, and are therefore a good model for examining behavior responses and brain activation. The present study extends our previous analysis to other brain areas. We imaged four male marmosets while presenting periovulatory, ovariectomized female scents and vehicle controls to assess key neural structures involved in stimulus processing for positive affective (reward) sexual chemosensory signals.