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.

Personal security agent: KQML-based PKI

Abstract: Certificate management infrastructure, a.k.a. PKI (Public Key Infrastructure), which issues and provides access to public key certificates to preserve the integrity of a public key, is fundamental for electronic commerce and business across the Internet. To satisfy the requirements of various applications, PKI should demonstrate customization to user needs, interoperability and flexibility in its implementations so it can satisfy the needs of various applications. Particularly, due to the popularity of software agent-based applications over the Internet, security will be urgently needed by the “agent society”. We propose to implement the authority of authentication verification service systems as personal autonomous software agents, called security agents. In this paper, we present two aspects of KQML-based PKI: 1. the security agent concept and its functional modules; 2. an extension of KQML, which is needed for public key management and secure communications among security agents and application agents.

Defining the epoch we live in

Abstract: Human alterations of Earth's environments are pervasive. Visible changes include the built environment, conversion of forests and grasslands to agriculture, algal blooms, smog, and the siltation of dams and estuaries. Less obvious transformations include increases in ozone, carbon dioxide (CO2), and methane (CH4) in the atmosphere, and ocean acidification. Motivated by the pervasiveness of these alterations, Crutzen and Stoermer argued in 2000 that we live in the “Anthropocene,” a time in which humans have replaced nature as the dominant environmental force on Earth ( 1 ). Many of these wide-ranging changes first emerged during the past 200 years and accelerated rapidly in the 20th century ( 2 ). Yet, a focus on the most recent changes risks overlooking pervasive human transformations of Earth's surface for thousands of years, with profound effects on the atmosphere, climate, and biodiversity.

X-Band Polarimetric Radar Measurements of Rainfall

Abstract: A combined polarimetric estimator for rainfall rate (R) retrievals from polarimetric radar measurements at X band is proposed. This estimator uses the horizontal polarization radar reflectivity Ze, differential reflectivity ZDR, and specific differential phase shift KDP, and it intrinsically accounts for changes in how drop oblateness increases with size. Because this estimator uses power measurements (i.e., Ze and ZDR), a procedure for correcting these measurements for effects of partial attenuation and differential attenuation using the differential phase measurement is suggested. An altitude correction for estimates of rainfall rates is also suggested. The proposed combined polarimetric estimator that uses KDP, ZDR, and Ze, an estimator that uses KDP alone for equilibrium drop shapes, and different Ze–R relations were applied to the 15 rain events observed with the NOAA X-band transportable polarimetric radar during the eight-week field campaign at the NASA Wallops Island facility in Virginia....

Aerosols from Overseas Rival Domestic Emissions over North America

Abstract: Many types of aerosols have lifetimes long enough for their transcontinental transport, making them potentially important contributors to air quality and climate change in remote locations. We estimate that the mass of aerosols arriving at North American shores from overseas is comparable with the total mass of particulates emitted domestically. Curbing domestic emissions of particulates and precursor gases, therefore, is not sufficient to mitigate aerosol impacts in North America. The imported contribution is dominated by dust leaving Asia, not by combustion-generated particles. Thus, even a reduction of industrial emissions of the emerging economies of Asia could be overwhelmed by an increase of dust emissions due to changes in meteorological conditions and potential desertification.