3,628 research outputs found
Adaptive-rate techniques for frequency-hop multiple-access packet-radio networks
No full textThe effects of adaptive-rate transmissions and routing on the total throughput of a slow-frequency-hop packet-radio network are considered. Adaptive rates are achieved through the use of error-control coding with perfect side information. Both fixed-length codes and variable-length codes are considered. Performance results are obtained for direct transmission (i.e., no routing), two-hop limited routing, and full routing. Each link metric is a function of the amount of interference caused by using the link. We compare the total network throughput for each of these schemes with both fixed-rate and adaptive-rate coding.United States. Dept. of the Air Force (FA8721-05-C-0002
Packet acquisition for time-frequency hopped asynchronous random multiple access
No full textPacket acquisition for a time-frequency hopped asynchronous random multiple access (RMA) system is investigated. A novel analytical approach to performance evaluation is provided, which enables the waveform designer to quickly evaluate the network performance as various waveform design and RMA protocol parameters and are chosen. The results show that the network throughput is estimated and upper-bounded by the acquisition performance. The performance evaluation procedure is broadly general, allowing for variations in waveform parameters, network topology, network population and population heterogeneity (in, e.g., rate, transmit power, and medium access behavior). To illustrate the accuracy of the analytical results, simulations are performed over a wide range of waveform, RMA protocol and network parameters.United States. Dept. of the Air Force (FA8721-05-C-0002
Routing and power control in frequency-hop random-access ad hoc networks
No full textFrequency hopping provides some protection against multiple access interference in random-access ad hoc networks. Power control and the use of short routing hops can further reduce interference by promoting spatial reuse. If the network is fully connected, frequency hopping and power control alone may be sufficient to allow good throughput without the use of routing. This approach is particularly desirable as avoiding routing can simplify network setup and reduce packet delay. However, if the network is heavily loaded, frequency hopping may no longer sufficiently protect against interference, so including routing may be beneficial. In this paper, we consider application of least interference routing (LIR) to frequency hop random-access networks. The performance of a family of LIR metrics is considered for a variety of networks to determine which cases multi-hop routing should be used, and it is shown that the choice of the optimal metric is sensitive to several network characteristics.United States. Dept. of the Air Force (Contract FA8721-05-C-0002
Map of W. J. Faucett's Subdivision of Block Number 23, Central Park Addition to Abilene, Texas
No full textMap of W. J. Faucett's Subdivision in the City of Abilene, Texas bordered by Hickory and Frederick streets, and divided by Orange Street. The block is divided into numbered segments showing property divisions. Scale 1:1,200
Faults - Midway between campus and "U"
No full textBlack and white photograph by Fred Pack showing exposed faults between the University of Utah campus and the Block "U" to the north.. Date undetermined
Geology students - near base of "U"
No full textBlack and white photograph by Fred Pack showing some of his geology students at the base of the "Block U" on the hill just north of the University of Utah campus, Salt Lake City. Date undetermined
Map of Alex J. Miller's Subdivision, Block Number 13, Central Park Addition to Abilene, Texas
No full textMap of Alex J. Miller's Subdivision in the City of Abilene, Texas bordered by Pine, Frederick, and North 15th streets. The block is divided into numbered segments showing property divisions. Scale 1:1,200
Memo from Fred J. Haller, Heart Mountain Project Steward, to Block Manager, April 24, 1944
No full textMemorandum of understanding from Fred J. Haller to Block Manager regarding new process for baby formula at Heart Mountain incarceration camp.The Japanese American Archival Collection documents the people, places, and daily life of Japanese Americans, primarily those who lived in the once thriving community of pre-war Florin in the Sacramento region, as well as the conditions in American incarceration camps during World War II. The approximately 7,000 original items include personal and official letters, photographs, diaries, arts and crafts, newsletters, textiles, camps artifacts, yearbooks and other publications
Map of Alex J. Miller's Subdivision of the East 300 Feet of Block Number 24, Central Park Addition to Abilene, Texas
No full textMap of Alex J. Miller's Subdivision in the City of Abilene, Texas bordered by Hickory, Orange, and Frederick streets. The block is divided into numbered segments showing property divisions. Scale 1:1,200
The Felix: An Island Tale
No full textThis paperback book of 149 pages is in the same format as Fables from an Island by the same author from 1981. It was available on eBay at the same time and promoted as fables from an island. I have read the prologue and first chapter and found them involving. I want to go on with this book about a handsome young islander who went off to World War II and came back mentally and physically damaged. The title page is signed by J. Stella Sonier. While there are no fables here, this book is a valuable complement to the earlier book by Sonier. And I hope it will find another reader--like me--sometime in the future.Signed by J. Stella SonierJ. Stella Sonie
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