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.

Information Systems Development and Data Modeling: Conceptual and Philosophical Foundations

Abstract: Data modelling was hypothesised to be the salvation of an organisation's data problems. This book aims to analyse the problems encountered and to present a comparative philosophical study of the various approaches. The authors explore the epistemology, ontology and rationality of each modelling approach, and describe the underlying assumptions embedded in them.

The search for organic substances and inorganic volatile compounds in the surface of Mars

Abstract: A total of four Martian samples, one surface and one subsurface sample at each of the two Viking landing sites, Chryse Planitia and Utopia Planitia, have been analyzed for organic compounds by a gas chromatograph-mass spectrometer. In none of these experiments could organic material of Martian origin be detected at detection limits generally of the order of parts per billion and for a few substances closer to parts per million. The evolution of water and carbon dioxide, but not of other inorganic gases, was observed upon heating the sample to temperatures of up to 500 C. The absence of organic compounds seems to preclude their production on the planet at rates that exceed the rate of their destruction. It also makes it unlikely that living systems that behave in a manner similar to terrestrial biota exist, at least at the two Viking landing sites.

Multiferroic materials and magnetoelectric physics: symmetry, entanglement, excitation, and topology

Abstract: Multiferroics are those materials with more than one ferroic order, and magnetoelectricity refers to the mutual coupling between magnetism and electricity. The discipline of multiferroicity has never been so highly active as that in the first decade of the twenty-first century, and it has become one of the hottest disciplines of condensed matter physics and materials science. A series of milestones and steady progress in the past decade have enabled our understanding of multiferroic physics substantially comprehensive and profound, which is further pushing forward the research frontier of this exciting area. The availability of more multiferroic materials and improved magnetoelectric performance are approaching to make the applications within reach. While seminal review articles covering the major progress before 2010 are available, an updated review addressing the new achievements since that time becomes imperative. In this review, following a concise outline of the basic knowledge of multiferroicity and magnetoelectricity, we summarize the important research activities on multiferroics, especially magnetoelectricity and related physics in the last six years. We consider not only single-phase multiferroics but also multiferroic heterostructures. We address the physical mechanisms regarding magnetoelectric coupling so that the backbone of this divergent discipline can be highlighted. A series of issues on lattice symmetry, magnetic ordering, ferroelectricity generation, electromagnon excitations, multiferroic domain structure and domain wall dynamics, and interfacial coupling in multiferroic heterostructures, will be revisited in an updated framework of physics. In addition, several emergent phenomena and related physics, including magnetic skyrmions and generic topological structures associated with magnetoelectricity will be discussed.

Bankruptcy Prediction with Industry Effects

Abstract: This paper investigates the forecasting accuracy of bankruptcy hazard rate models for U.S. companies over the time period 1962-1999 using both yearly and monthly observation intervals. The contribution of this paper is multiple-fold. One, using an expanded bankruptcy database we validate the superior forecasting performance of Shumway's (2001) model as opposed to Altman (1968) and Zmijewski (1984). Two, we demonstrate the importance of including industry effects in hazard rate estimation. Industry groupings are shown to significantly affect both the intercept and slope coeffi- cients in the forecasting equations. Three, we extend the hazard rate model to apply to financial firms and monthly observation intervals. Due to data limitations, most of the existing literature employs only yearly observations. We show that bankruptcy prediction is markedly improved using monthly observation intervals. Fourth, consistent with the notion of market efficiency with respect to publicly available information, we demonstrate that accounting variables add little predictive power when market variables are already included in the bankruptcy model.

The Dynamics of Alignment: Insights from a Punctuated Equilibrium Model

Abstract: Several prior articles have emphasized the importance of alignment between business and information system (IS) strategies, and between business and IS structures. Seeking to advance our understanding of alignment, we examine the dynamics of changes in alignment through strategy/structure interactions in the business and IS domains. More specifically, we address the following question:In what ways does alignment evolve over time? Changes in the strategic IS management profile (which includes business strategy, IS strategy, business structure, and IS structure) over time are examined using a punctuated equilibrium model, involving long periods of relative stability, or evolutionary change, interrupted by short periods of quick and extensive, or revolutionary, change. Case studies of changes in business and IS strategies and structure over long time periods in three organizations suggest that the punctuated equilibrium model provides a valuable perspective for viewing these dynamics.The cases suggest that a pattern of alignment may continue over a long period, because either the level of alignment is high or the managers do not recognize the low alignment as a problem. Revolutions, involving changes in most or all dimensions of the strategic IS management profile, interrupt the evolutionary changes. However, organizations hesitate to make such revolutionary changes in strategic IS management profiles. Complete revolutions apparently require a combination of strong triggers. Finally, post-revolution adjustments to one dimension of the strategic IS management profile seem to follow revolutionary changes.