University of Houston

About: University of Houston is a education organization based out in Houston, Texas, United States. It is known for research contribution in the topics: Population & Poison control. The organization has 23074 authors who have published 53903 publications receiving 1641968 citations.

Precarious Politics and Return Volatility

Abstract: We examine how local and global political risks affect industry return volatility. Our central premise is that some industries are more sensitive to political events than others. We find that industries that are more dependent on trade, contract enforcement, and labor exhibit greater return volatility when local political risks are higher. Political uncertainty in countries of trading partners of trade-dependent industries similarly results in greater volatility. Volatility decomposition results indicate that while systematic volatility is associated with domestic political uncertainty, global political risks translate into larger idiosyncratic volatility. The Author 2011. Published by Oxford University Press on behalf of The Society for Financial Studies. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com., Oxford University Press.

Fuel-cost minimisation for both real-and reactive-power dispatches

Abstract: The fuel cost formula is developed for optimal real-and reactive-power dispatch for the economic operation of power systems The problem is decomposed into a P-optimisation and a Q-optimisation module, where both modules use the same fuel cost objective function resulting in the optimal load flow The control variables are generator real-power outputs for the real-power module; and generator reactive-power outputs, shunt capacitors/reactors and transformer tap settings for the reactive-power module The constraints are the operating limits of the control variables, power-line flows and busbar voltages The optimisation problem is solved using the gradient projection method (GPM) for the quadratic objective function and linear constraints The GPM allows the use of functional constraints without the need of penalty functions or Lagrange multipliers among other advantages Mathematical models are developed to represent the sensitivity relationships between dependent and control variables for both real- and reactive-power optimisation modules; and thus eliminate the use of B-coefficients Results of two test systems are presented and compared with conventional methods

Location-based services

Abstract: Evaluating user perceptions of location-tracking and location-awareness services.

Decadal Sea Surface Temperature Variability in the Subtropical South Pacific from 1726 to 1997 A.D.

Abstract: We present a 271-year record of Sr/Ca variability in a coral from Rarotonga in the South Pacific gyre. Calibration with monthly sea surface temperature (SST) from satellite and ship measurements made in a grid measuring 1 degrees by 1 degrees over the period from 1981 to 1997 indicates that this Sr/Ca record is an excellent proxy for SST. Comparison with SST from ship measurements made since 1950 in a grid measuring 5 degrees by 5 degrees also shows that the Sr/Ca data accurately record decadal changes in SST. The entire Sr/Ca record back to 1726 shows a distinct pattern of decadal variability, with repeated decadal and interdecadal SST regime shifts greater than 0. 75 degrees C. Comparison with decadal climate variability in the North Pacific, as represented by the Pacific Decadal Oscillation index (1900-1997), indicates that several of the largest decadal-scale SST variations at Rarotonga are coherent with SST regime shifts in the North Pacific. This hemispheric symmetry suggests that tropical forcing may be an important factor in at least some of the decadal variability observed in the Pacific Ocean.

Soft Ultrathin Electronics Innervated Adaptive Fully Soft Robots.

Abstract: Soft robots outperform the conventional hard robots on significantly enhanced safety, adaptability, and complex motions. The development of fully soft robots, especially fully from smart soft materials to mimic soft animals, is still nascent. In addition, to date, existing soft robots cannot adapt themselves to the surrounding environment, i.e., sensing and adaptive motion or response, like animals. Here, compliant ultrathin sensing and actuating electronics innervated fully soft robots that can sense the environment and perform soft bodied crawling adaptively, mimicking an inchworm, are reported. The soft robots are constructed with actuators of open-mesh shaped ultrathin deformable heaters, sensors of single-crystal Si optoelectronic photodetectors, and thermally responsive artificial muscle of carbon-black-doped liquid-crystal elastomer (LCE-CB) nanocomposite. The results demonstrate that adaptive crawling locomotion can be realized through the conjugation of sensing and actuation, where the sensors sense the environment and actuators respond correspondingly to control the locomotion autonomously through regulating the deformation of LCE-CB bimorphs and the locomotion of the robots. The strategy of innervating soft sensing and actuating electronics with artificial muscles paves the way for the development of smart autonomous soft robots.