68,151 research outputs found
The Automated Astronomic Positioning System (AAPS)
Two prototype systems of The Automated Astronomic Positioning System (AAPS) have been delivered to Defense Mapping Agency (DMA). The AAPS was developed to automate and expedite the determination of astronomic positions (latitude and longitude). This equipment is capable of defining astronomic positions to an accuracy sigma = 0.3 in each component within a two hour span of stellar observations which are acquired automatically. The basic concept acquires observations by timing stellar images as they cross a series of slits, comparing these observations to a stored star catalogue, and automatically deducing position and accuracy by least squares using pre-set convergence criteria. An exhaustive DMA operational test program has been initiated to evaluate the capabilities of the AAPS in a variety of environments (both climatic and positional). Status of the operational test is discussed
On the use of Satellite Television in High Energy Physics
This paper assesses the feasibility of exploiting commercial satellite
television technologies to broadcast video signals and data from major High
Energy Physics facilities to collaborating institutes throughout the world.Comment: Invited talk at CHEP'98, Chicago, USA, August 31 - September 4, 199
What risks and challenges do credit default swaps pose to the stability of financial markets?
Credit default swaps (CDSs) pose a number of risks to institutions and markets, many of which are not unique. These risks include counterparty credit, operational, concentration, and jump-to-default risks. CDSs also pose other risks and challenges. For example, CDS markets generally lacked transparency, which may have compounded market uncertainty about participants’ overall risk exposures, the concentration of exposures, and the market value of contracts during the recent crisis. Further, regulators note that the potential existed for market participants to manipulate certain CDS prices to profi t in other markets that CDS prices might infl uence, such as the equity market, and that the lack of transparency could contribute to this risk. Others also raised concerns about the use of CDSs for speculative purposes, including concerns about uncovered or “naked” CDS positions – the use of CDSs for speculative purposes when a party to a CDS contract does not own the underlying reference entity or obligation. While regulators and market participants note that over-the-counter (OTC) derivatives, to varying degrees, pose some similar risks, particularly equity derivatives, the US regulatory structure for CDSs does not provide any one regulator with authority over all participants in the CDS market, thereby making monitoring and managing potential systemic risk diffi cult.
The Development of Web-Based Interface to Census Interaction Data
This project involves the development of a Web interface to origin-destination statistics from the 1991 Census (in a form that will be compatible with planned 2001 outputs). It provides the user with a set of screen-based tools for setting the parameters governing each data extraction (data set, areas, variables) in the form of a query. Traffic light icons are used to signal what the user has set so far and what remains to be done. There are options to extract different types of flow data and to generate output in different formats. The system can now be used to access the interaction flow data contained in the 1991 Special Migration Statistics Sets 1 and 2 and Special Workplace Statistics Set C. WICID has been demonstrated at the Origin-Destination Statistics Roadshows organised by GRO Scotland and held during May/June 2000 and the Census Offices have expressed interest in using the software in the Census Access Project
Distribution of heavy metals in sediments of Igbede, Ojo and Ojora rivers of Lagos, Nigeria
The distribution of some heavy metals,
namely Cd, Pb, Zn, Fe, Cu, Cr and Mn in epipellic
sediments of Igbede, Ojo and Ojora rivers of Lagos
was studied weekly in the early summer (November)
of 2003. The levels of selected trace metals were determined
using Atomic Absorption Spectrophotometer
(UNICAM 969 AAS SOLAR). Trends in heavy metal
burdens in the sediments revealed weekly variations in
all the rivers assessed. Statistical analyses also showed
different mean levels of trace metals in the aquatic environments,
the distribution of which followed the sequence
Fe > Zn > Mn > Pb > Cu > Cr > Cd, Fe
> Zn > Cu > Mn > Pb > Cr > Cd and Fe > Zn >
Mn > Cu > Cr > Pb > Cd in Igbede, Ojo and Ojora
rivers respectively. Fe recorded the highest concentration
levels (1,582.95 ± 96.57 μg/g–1,910.34 ± 723.19
μg/g) in all the sediments investigated while the Cd
levels (0.06 ± 0.10 μg/g–0.47 ± 0.36 μg/g) were the
lowest. Expectedly, trace metal concentrations in fine
grain muddy sediments of the Igbede and Ojo coastline
were much higher than those of Ojora which consist
of coarse and sandy deposits covering the near shore
area. Generally, the results obtained fell within toler-able limits stipulated by World Health Organization
(WHO)
Measuring Confidentiality Risks in Census Data
Two trends have been on a collision course over the recent past. The first is the increasing demand by researchers for greater detail and flexibility in outputs from the decennial Census of Population. The second is the need felt by the Census Offices to demonstrate more clearly that Census data have been explicitly protected from the risk of disclosure of information about individuals. To reconcile these competing trends the authors propose a statistical measure of risks of disclosure implicit in the release of aggregate census data. The ideas of risk measurement are first developed for microdata where there is prior experience and then modified to measure risk in tables of counts. To make sure that the theoretical ideas are fully expounded, the authors develop small worked example. The risk measure purposed here is currently being tested out with synthetic and a real Census microdata. It is hoped that this approach will both refocus the census confidentiality debate and contribute to the safe use of user defined flexible census output geographies
Measuring Confidentiality Risks in Census Data
Two trends have been on a collision course over the recent past. The first is the increasing demand by researchers for greater detail and flexibility in outputs from the decennial Census of Population. The second is the need felt by the Census Offices to demonstrate more clearly that Census data have been explicitly protected from the risk of disclosure of information about individuals. To reconcile these competing trends the authors propose a statistical measure of risks of disclosure implicit in the release of aggregate census data. The ideas of risk measurement are first developed for microdata where there is prior experience and then modified to measure risk in tables of counts. To make sure that the theoretical ideas are fully expounded, the authors develop small worked example. The risk measure purposed here is currently being tested out with synthetic and a real Census microdata. It is hoped that this approach will both refocus the census confidentiality debate and contribute to the safe use of user defined flexible census output geographies
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