Cover Time and Broadcast Time

We introduce a new technique for bounding the cover time of random walks by relating it to the runtime of randomized broadcast. In particular, we strongly confirm for dense graphs the intuition of Chandra et al. (1997) that ``the cover time of the graph is an appropriate metric for the performance of certain kinds of randomized broadcast algorithms\u27\u27. In more detail, our results are as follows: begin{itemize} item For any graph $G=(V,E)$ of size $n$ and minimum degree $delta$, we have $mathcal{R}(G)= mathcal{O}(frac{|E|}{delta} cdot log n)$, where $mathcal{R}(G)$ denotes the quotient of the cover time and broadcast time. This bound is tight for binary trees and tight up to logarithmic factors for many graphs including hypercubes, expanders and lollipop graphs. item For any $delta$-regular (or almost $delta$-regular) graph $G$ it holds that $mathcal{R}(G) = Omega(frac{delta^2}{n} cdot frac{1}{log n})$. Together with our upper bound on $mathcal{R}(G)$, this lower bound strongly confirms the intuition of Chandra et al.~for graphs with minimum degree $Theta(n)$, since then the cover time equals the broadcast time multiplied by $n$ (neglecting logarithmic factors). item Conversely, for any $delta$ we construct almost $delta$-regular graphs that satisfy $mathcal{R}(G) = mathcal{O}(max { sqrt{n},delta } cdot log^2 n)$. Since any regular expander satisfies $mathcal{R}(G) = Theta(n)$, the strong relationship given above does not hold if $delta$ is polynomially smaller than $n$. end{itemize} Our bounds also demonstrate that the relationship between cover time and broadcast time is much stronger than the known relationships between any of them and the mixing time (or the closely related spectral gap)

Efficacy of Broadcast Phosphorus Fertilizer Applied in Fall or Spring for No-Till Corn and Soybean

Broadcast fertilization could be an inefficient placement method with no-till because phosphorus (P) tends to accumulate at or near the soil surface. However, long-term research at this farm has shown no difference between banded and broadcast P fertilizer placement methods for corn and soybean managed with no-till or chisel-plow tillage, even with significant stratification of soil-test P. One possible explanation for this result is that broadcast P was always applied in the fall because this is what most Iowa farmers do. We theorize that such an advance application could provide sufficient time for fertilizer granules or dissolved P to move below the residue cover as a result of rain, freezing and thawing, and/or macrofauna activity. To test this hypothesis, a study was conducted to compare fall and spring broadcast P fertilizer application for no-till corn and soybean

An operational all-weather Great Lakes ice information system

A description is given of the NASA developed all-weather ice information system for the Great Lakes winter navigation program. The system utilizes an X-band side looking airborne radar (SLAR) for determining type, location, and areal distribution of the ice cover in the Great Lakes and an airborne, S band, down looking short pulse radar for obtaining ice thickness. Digitized SLAR data are relayed in real time via the NOAA-GOES satellite in geosynchronous orbit. The SLAR images along with hand drawn interpretative ice charts for various Great Lakes winter shipping areas are broadcast to facsimile recorders aboard vessles is the area via the MARAD marine VHF-FM radio network. These data assist such vessels in navigating both through and around the ice

Markovian Model for Broadcast in Wireless Body Area Networks

International audienceWireless body area networks became recently a vast field of investigation. A large amount of research in this field is dedicated to the evaluation of various communication protocols, e.g., broadcast or convergecast, against human body mobility. Most of the time this evaluation is done via simulations and in many situations only synthetic data is used for the human body mobility. In this paper we propose for the first time in Wireless Body Area Networks a Markovian analytical model specifically designed for WBAN networks. The main objective of the model is to evaluate the efficiency of a multi-hop transmission in the case of a diffusion-based broadcast protocol, with respect to various performance parameters (e.g., cover probability, average cover number, hitting probability or average cover time). We validate our model by comparing its results to simulation and show its accuracy. Finally, but not least, we show how our model can be used to analytically evaluate the trade-off between transmission power and redundancy, when the same message is broadcasted several times in order to increase the broadcast reliability while maintaining a low transmission power

Herald of Holiness Volume 87 Number 09 (1998)

Cover Photo and Art Credit: Comstock, Miller, and Pluff FEATURES 2 Leftovers for God?, Mark Barnes 5 Mine? Or His?, Richard Maffeo 6 No Pain, No Gain, Stephen Lim 9 Is It My Turn?, June Cerza Kolf 12 Sanctification- A Comprehensive Provision, Al Truesdale and Bonnie Perry 18 Grilled-Cheese-Sandwich Time, Grant Lee CONTINUING COLUMNS (Inside front cover) General Superintendent’s Viewpoint, William J. Prince 4 Guest Editorial, Loren P. Gresham 8 The Family Album, Jerry & Lynda Cohagan 10 The Unheralded, J. Wesley Eby 15 Words of Faith, Rob L. Staples DEPARTMENTS 14 The Readers Write 16-17, 21-22 News 20 The Question Box 22 NCN Broadcast Schedule 23 Late Newshttps://digitalcommons.olivet.edu/cotn_hoh/1008/thumbnail.jp

Great Lakes all-weather ice information system

A system is described which utilizes an X-band Side-Looking-Airborne-Radar (SLAR) for determining type, location, and aerial distribution of the ice cover in the Great Lakes and an airborne, S-band, short pulse radar for obtaining ice thickness. The SLAR system is currently mounted aboard a U.S. Coast Guard C-130B aircraft. Digitized SLAR data are relayed in real-time via the NOAA-GOES-1 satellite in geosynchronous orbit to the U.S. Coast Guard Ice Center in Cleveland, Ohio. SLAR images along with hand-drawn interpretative ice charts for various winter shipping areas in the Great Lakes are broadcast to facsimile recorders aboard Great Lakes vessels. The operational aspects of this ice information system are being demonstrated by NASA, U.S. Coast Guard, and NOAA/National Weather Service. Results from the 1974-75 winter season demonstrated the ability of this system to provide all-weather ice information to shippers in a timely manner

Cover cropping to improve the sustainability of agronomic production systems

The adoption rate of cover cropping among farmers in the Southeast is low due to the lack of knowledge regarding the suitable cover crop species and their management practices and the concerns of resource depletion for the subsequent cash crop. To generate information addressing the above knowledge gap, the present research was conducted with the following objectives: (1) to determine the optimal planting method for winter cover crops in the upstate of SC and whether it is influenced by the seeding rates (Project-1); (2) to determine suitable winter cover crops for the region based on biomass production, water use efficiency (WUE), weed suppression, soil water conservation, soil health, and the performance of the following cash crop (Project-2); and (3) to test the efficacy of cover crop inter-seeding in the region (Project-3). In project-1, we evaluated the drill and broadcast planting methods and found that the advantage of drilling depends upon the cover crops, and broadcasting will just work well for some cover crops even without increasing the seeding rate. In Project-2, we evaluated grasses, legumes, and brassicas as single species or mixtures and found that rye, the mixture of crimson clover and rye, and the mixture of Austrian winter pea, rye, crimson clover, hairy vetch, and oats are suitable cover crops for the region based on biomass production, WUE, weed suppression, soil water conservation, soil health, and the performance of the following cash crop. In project-3, we investigated whether we could enhance complementarity in a corn-cover crop inter-seeded system by adjusting the cover crop planting time. We found that the V10 growth stage of corn is a suitable time for inter-seeding cover crops to conserve soil moisture, improve soil health, and increase silage corn biomass. These results provide information to growers for cover crop selection and management practices in SC