COSPAS/SARSAT 406-MHz emergency beacon digital controller

The digital control portion of a low-cost 406-MHz COSPAS/SARSAT emergency beacon has been designed and breadboarded at the NASA Lewis Research Center. This report discusses the requirements and design tradeoffs of the digital controller and describes the hardware and software design, which is available only to United States citizens and companies

Circuit-switch architecture for a 30/20-GHz FDMA/TDM geostationary satellite communications network

A circuit switching architecture is described for a 30/20 GHz frequency division, multiple access uplink/time division multiplexed downlink (FDMA/TDM) geostationary satellite communications network. Critical subsystems and problem areas are identified and addressed. Work was concentrated primarily on the space segment; however, the ground segment was considered concurrently to ensure cost efficiency and realistic operational constraints

Evaluation of directional vacuum-assisted breast biopsy: Report for the National Breast Cancer Centre final report, CHERE Project Report No 21

This project was commissioned by the National Breast Cancer Centre (NBCC). The objectives of the project, as set out in the call for expressions of interest, were to determine: 1. The costs associated with the introduction and use of directional vacuum-assisted breast biopsy(DVA breast biopsy) in Australia; and 2. Whether directional vacuum-assisted breast biopsy used for diagnostic purposes is cost-effectivein Australia when compared to core biopsy. The motivation for commissioning the project was an assessment of directional vacuum-assisted breast biopsy conducted by the Medical Services Advisory Committee (MSAC) which concluded that the procedure is safe and more effective than core biopsy. Although a cost-effectiveness analysis was not conducted as part of the MSAC study, MSAC recommended that the costs associated with the procedure be investigated and that, pending a review of costs, the procedure receive interim Medicare funding at a higher level than was previously available. For the project reported here, data was required to be collected from both public and private sectors on the cost of introducing and using DVA breast biopsy and a cost-effectiveness analysis (CEA) conducted on the introduction and use of DVA breast biopsy with and without a prone table. The research question for the CEA was What is the impact on costs and number of open biopsies performed of using DVA breast biopsy compared to core biopsy for micro-calcification lesions? It is important to note that this question specifies both the outcome the CEA (change in the number of core biopsies performed) and that the investigation was to be confined to micro-calcification lesions only. An expert multidisciplinary working group was assembled to oversee the project. Following collection of data an interim report was produced for the working group. As DVABB is a relatively new technology in Australia the interim report indicated that the current number of sites performing DVABB and the level of experience of users was insufficient to provide meaningful data to achieve the project aims. On the advice of the working group it was agreed to suspend the project at this juncture. The NBCC will consider repeating the survey in the future.Breast cancer, diagnostics, breast biopsy, Australia

Understanding Price Variation Across Stores and Supermarket Chains: Some Implications for CPI Aggregation Methods

The empirical literature on price indices consistently finds that aggregation methods have a considerable impact, particularly when scanner data are used. This paper outlines a novel approach to test for the homogeneity of goods and hence for the appropriateness of aggregation. A hedonic regression framework is used to test for item homogeneity across four supermarket chains and across stores within each of these supermarket chains. We find empirical support for the aggregation of prices across stores which belong to the same supermarket chain. Support was also found for the aggregation of prices across three of the four supermarket chains.Price indexes; aggregation; scanner data; unit values; item homogeneity; hedonics

Can Dissimilarity Indexes Resolve the Issue of When to Chain Price Indexes?

Chaining is used in index number construction to update weights and link new items into an index. However, chained indexes can suffer from, sometimes substantial, drift. The Consumer Price Index Manual (ILO, 2004) recommends the use of dissimilarity indexes to determine when chaining is appropriate. This study provides the first empirical application of dissimilarity indexes in this context. We find that dissimilarity indexes do not appear to be sufficient to resolve the issue of when to chain.Index numbers; price indexes; chain drift; dissimilarity

Destination-directed, packet-switching architecture for 30/20-GHz FDMA/TDM geostationary communications satellite network

A destination-directed packet switching architecture for a 30/20-GHz frequency division multiple access/time division multiplexed (FDMA/TDM) geostationary satellite communications network is discussed. Critical subsystems and problem areas are identified and addressed. Efforts have concentrated heavily on the space segment; however, the ground segment has been considered concurrently to ensure cost efficiency and realistic operational constraints

Destination directed packet switch architecture for a 30/20 GHz FDMA/TDM geostationary communication satellite network

Emphasis is on a destination directed packet switching architecture for a 30/20 GHz frequency division multiplex access/time division multiplex (FDMA/TDM) geostationary satellite communication network. Critical subsystems and problem areas are identified and addressed. Efforts have concentrated heavily on the space segment; however, the ground segment was considered concurrently to ensure cost efficiency and realistic operational constraints

Satellites and the BISDN: An overview of NASA R/D

NASA is currently the only U.S. government agency developing advanced technology on behalf of the commercial communications satellite industry. The Agency's commercial communications program includes several activities which are either directly or indirectly related to the potential use of satellites within a broadband integrated services digital network (BISDN). Lewis Research Center's Space Electronics Division is actively pursuing a number of thrusts aimed at the integration of satellites into the BISDN through the development of high-risk and proof-of-concept technology