University of Maryland, Baltimore County

About: University of Maryland, Baltimore County is a education organization based out in Baltimore, Maryland, United States. It is known for research contribution in the topics: Population & Galaxy. The organization has 8749 authors who have published 20843 publications receiving 795706 citations. The organization is also known as: UMBC.

A critical examination of the residual cloud contamination and diurnal sampling effects on MODIS estimates of aerosol over ocean

Abstract: Observations of the aerosol optical thickness (AOT) by the Moderate Resolution Imaging Spectroradiometer (MODIS) instruments aboard Terra and Aqua satellites are being used extensively for applications to climate and air quality studies. Data quality is essential for these studies. Here we investigate the effects of unresolved clouds on the MODIS measurements of the AOT. The main cloud effect is from residual cirrus that increases the AOT by 0.015/spl plusmn/0.003 at 0.55 /spl mu/m. In addition, lower level clouds can add contamination. We examine the effect of lower clouds using the difference between simultaneously measured MODIS and AERONET AOT. The difference is positively correlated with the cloud fraction. However, interpretation of this difference is sensitive to the definition of cloud contamination versus aerosol growth. If we consider this consistent difference between MODIS and AERONET to be entirely due to cloud contamination we get a total cloud contamination of 0.025/spl plusmn/0.005, though a more likely estimate is closer to 0.020 after accounting for aerosol growth. This reduces the difference between MODIS-observed global aerosol optical thickness over the oceans and model simulations by half, from 0.04 to 0.02. However it is insignificant for studies of aerosol cloud interaction. We also examined how representative are the MODIS data of the diurnal average aerosol. Comparison to monthly averaged sunphotometer data confirms that either the Terra or Aqua estimate of global AOT is a valid representation of the daily average. Though in the vicinity of aerosol sources such as fires, we do not expect this to be true.

The role of feedback in the process of health behavior change.

Abstract: Objective To offer a taxonomy of types of feedback and describe potential mechanisms of action particularly in the area of addictive behaviors. Method Reviewed the literature to examine support for types-Generic, Targeted, and Personalized-and for mechanisms of feedback. Results Although it is not clear how it works, feedback is thought to offer important information, to create a sense of caring and helping relationship, to reach more directly decisional considerations, to increase engagement in the materials, to increase motivation, or to provide social comparison and norms. Conclusions Avenues for future research in search of the most effective manner of using feedback to promote health behavior change are discussed.

Evaluation of the New Version of the Laser-Optical Disdrometer, OTT Parsivel2

Abstract: A comparative study of raindrop size distribution measurements has been conducted at NASA's Goddard Space Flight Center where the focus was to evaluate the performance of the upgraded laser-optical OTT Particle Size Velocity (Parsivel2; P2) disdrometer The experimental setup included a collocated pair of tipping-bucket rain gauges, OTT Parsivel (P1) and P2 disdrometers, and Joss-Waldvogel (JW) disdrometers Excellent agreement between the two collocated rain gauges enabled their use as a relative reference for event rain totals A comparison of event total showed that the P2 had a 6%absolute bias with respect to the reference gauges, considerably lower than the P1 and JW disdrometers Good agreement was also evident between the JW and P2 in hourly raindrop spectra for drop diameters between 05 and 4 mm The P2 drop concentrations mostly increased toward small sizes, and the peak concentrations were mostly observed in the first three measurable size bins The P1, on the other hand, underestimated small drops and overestimated the large drops, particularly in heavy rain rates From the analysis performed, it appears that the P2 is an improvement over the P1 model for both drop size and rainfall measurements P2 mean fall velocities follow accepted terminal fall speed relationships at drop sizes less than 1 mm As a caveat, the P2 had approximately 1ms21 slower mean fall speed with respect to the terminal fall speed near 1 mm, and the difference between the mean measured and terminal fall speeds reduced with increasing drop size This caveat was recognized as a software bug by the manufacturer and is currently being investigated

The growth effects of sport franchises, stadia, and arenas

Abstract: This paper investigates the relationship between professional sports franchises and venues and real per capita personal income in 37 standard metropolitan statistical areas in the United States over the period 1969 to 1994. Our empirical framework accounts for the entry and departure of professional football, basketball, and baseball franchises; the construction of arenas and stadia; and other sports related factors over this time period. In contrast to other existing studies, we find evidence that some professional sports franchises reduce the level of per capita personal income in metropolitan areas and have no effect on the growth in per capita income, casting doubt on the ability of a new sports franchise or facility to spur economic growth. We also find evidence that results obtained from estimating reduced-form relationships, a common practice in the literature, are not robust to alternative reduced-form specifications. © 1999 by the Association for Public Policy Analysis and Management.

The SOUPA Ontology for Pervasive Computing

Abstract: This paper describes SOUPA (Standard Ontology for Ubiquitous and Pervasive Applications) and the use of this ontology in building the Context Broker Architecture (CoBrA). CoBrA is a new agent architecture for supporting pervasive context-aware systems in a smart space environment. The SOUPA ontology is expressed using the Web Ontology Language OWL and includes modular component vocabularies to represent intelligent agents with associated beliefs, desire, and intentions, time, space, events, user profiles, actions, and policies for security and privacy. Central to CoBrA is an intelligent broker agent that exploits ontologies to support knowledge sharing, context reasoning, and user privacy protection. We also describe two prototype systems that we have developed to demonstrate the feasibility and the use of CoBrA.