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 & Aerosol. The organization has 8749 authors who have published 20843 publications receiving 795706 citations. The organization is also known as: UMBC.

Distributed Recovery from Network Partitioning in Movable Sensor/Actor Networks via Controlled Mobility

Abstract: Mobility has been introduced to sensor networks through the deployment of movable nodes. In movable wireless networks, network connectivity among the nodes is a crucial factor in order to relay data to the sink node, exchange data for collaboration, and perform data aggregation. However, such connectivity can be lost due to a failure of one or more nodes. Even a single node failure may partition the network, and thus, eventually reduce the quality and efficiency of the network operation. To handle this connectivity problem, we present PADRA to detect possible partitions, and then, restore the network connectivity through controlled relocation of movable nodes. The idea is to identify whether or not the failure of a node will cause partitioning in advance in a distributed manner. If a partitioning is to occur, PADRA designates a failure handler to initiate the connectivity restoration process. The overall goal in this process is to localize the scope of the recovery and minimize the overhead imposed on the nodes. We further extend PADRA to handle multiple node failures. The approach, namely, MDAPRA strives to provide a mutual exclusion mechanism in repositioning the nodes to restore connectivity. The effectiveness of the proposed approaches is validated through simulation experiments.

Fermi-LAT discovery of GeV gamma-ray emission from the young supernova remnant Cassiopeia A

Abstract: We report on the first detection of GeV high-energy gamma-ray emission from a young supernova remnant with the Large Area Telescope aboard the Fermi Gamma-ray Space Telescope. These observations reveal a source with no discernible spatial extension detected at a significance level of 12.2$\sigma$ above 500 MeV at a location that is consistent with the position of the remnant of the supernova explosion that occurred around 1680 in the Cassiopeia constellation - Cassiopeia A. The gamma-ray flux and spectral shape of the source are consistent with a scenario in which the gamma-ray emission originates from relativistic particles accelerated in the shell of this remnant. The total content of cosmic rays (electrons and protons) accelerated in Cas A can be estimated as $W_{\mathrm{CR}} \approx (1-4) \times 10^{49}$ erg thanks to the well-known density in the remnant assuming that the observed gamma-ray originates in the SNR shell(s). The magnetic field in the radio-emitting plasma can be robustly constrained as B $\gt 0.1$ mG, providing new evidence of the magnetic field amplification at the forward shock and the strong field in the shocked ejecta.

Suomi‐NPP VIIRS aerosol algorithms and data products

Abstract: [1] The Visible Infrared Imaging Radiometer Suite (VIIRS) instrument on board the Suomi National Polar-orbiting Partnership (S-NPP) spacecraft was launched in October 2011. The instrument has 22 spectral channels with band centers from 412 nm to 12,050 nm. The VIIRS aerosol data products are derived primarily from the radiometric channels covering the visible through the short-wave infrared spectral regions (412 nm to 2250 nm). The major components of the VIIRS aerosol retrieval process are data screening, land inversion, ocean inversion, suspended matter typing, and aggregation. The primary data product produced is the aerosol optical thickness (AOT) environmental data record. A higher resolution AOT intermediate product is also produced. These AOT products and their corresponding retrieval algorithms are described in detail, including theoretical basis, retrieval limitations, and data quality flagging. Preliminary evaluation of the data products has been undertaken by the VIIRS aerosol calibration/validation team using Aerosol Robotic Network ground-based observations to show that the performance of AOT retrievals meets the requirements specified in the Joint Polar Satellite System Level 1 requirements.

English Language Proficiency and the Prediction of Academic Success

Abstract: This article discusses the relationship between English language proficiency and academic success in universities and colleges in which English is the language of instruction. It points out some of the difficulties associated with determining this relationship and summarizes previous investigations of the issue. It is argued that while the research clearly shows that many factors other than English proficiency are important to academic success, there may be for each institution, or even for each program within an institution, a minimum level below which lack of sufficient proficiency in English contributes significantly to lack of academic success. Such a level can be determined by each institution individually, but until it is determined, a number of steps can be taken for establishing reasonable English language proficiency requirements. At many colleges and universities, ESL professionals are called upon by admissions officers for help in making admissions decisions for nonnative speakers of English. ESL professionals may be asked what cutoff scores should be used on standardized tests that have

Discrimination Comes in Many Forms Individual, Institutional, and Structural

Abstract: Three different types of discrimination are defined and analyzed. Individual and institutional discrimination refer to actions and/or policies that are intended to have a differential impact on minorities and women. Structural discrimination, on the other hand, refers to policies that are race or gender neutral in intent but that have negative effects on women, minorities, or both. Concrete examples of each type of discrimination are presented and pedagogical techniques for using these concepts are provided.