Fractional Power Control for Decentralized Wireless Networks

We consider a new approach to power control in decentralized wireless networks, termed fractional power control (FPC). Transmission power is chosen as the current channel quality raised to an exponent -s, where s is a constant between 0 and 1. The choices s = 1 and s = 0 correspond to the familiar cases of channel inversion and constant power transmission, respectively. Choosing s in (0,1) allows all intermediate policies between these two extremes to be evaluated, and we see that usually neither extreme is ideal. We derive closed-form approximations for the outage probability relative to a target SINR in a decentralized (ad hoc or unlicensed) network as well as for the resulting transmission capacity, which is the number of users/m^2 that can achieve this SINR on average. Using these approximations, which are quite accurate over typical system parameter values, we prove that using an exponent of 1/2 minimizes the outage probability, meaning that the inverse square root of the channel strength is a sensible transmit power scaling for networks with a relatively low density of interferers. We also show numerically that this choice of s is robust to a wide range of variations in the network parameters. Intuitively, s=1/2 balances between helping disadvantaged users while making sure they do not flood the network with interference.Comment: 16 pages, in revision for IEEE Trans. on Wireless Communicatio

Possible Methods for Incunabula Digitization for Preservation and Analysis

This paper explores different approaches that PSU’s Special Collections Department might take toward digitizing its 1490 incunable containing Werner Rolewinck’s Fasciculus temporum and second-edition Malleus Maleficarum. Digitization will reduce wear-and-tear of the volume and allow access to its contents by a wider range of users.https://pdxscholar.library.pdx.edu/mmft_provenance/1001/thumbnail.jp

Detailed simulations of cell biology with Smoldyn 2.1.

Most cellular processes depend on intracellular locations and random collisions of individual protein molecules. To model these processes, we developed algorithms to simulate the diffusion, membrane interactions, and reactions of individual molecules, and implemented these in the Smoldyn program. Compared to the popular MCell and ChemCell simulators, we found that Smoldyn was in many cases more accurate, more computationally efficient, and easier to use. Using Smoldyn, we modeled pheromone response system signaling among yeast cells of opposite mating type. This model showed that secreted Bar1 protease might help a cell identify the fittest mating partner by sharpening the pheromone concentration gradient. This model involved about 200,000 protein molecules, about 7000 cubic microns of volume, and about 75 minutes of simulated time; it took about 10 hours to run. Over the next several years, as faster computers become available, Smoldyn will allow researchers to model and explore systems the size of entire bacterial and smaller eukaryotic cells

HOUSEHOLD FOOD SECURITY IN THE UNITED STATES, 2003

Eighty-nine percent of American households were food secure throughout the entire year in 2003, meaning that they had access, at all times, to enough food for an active, healthy life for all household members. The remaining households were food insecure at least some time during that year. The prevalence of food insecurity, 11.2 percent of households, was not statistically different from the 11.1 percent observed in 2002. The prevalence of food insecurity with hunger was unchanged at 3.5 percent. This report, based on data from the December 2003 food security survey, provides the most recent statistics on the food security of U.S. households, as well as on how much they spent for food and the extent to which food-insecure households participated in Federal and community food assistance programs. Survey responses indicate that the typical food-secure household in the U.S. spent 34 percent more on food than the typical food-insecure household of the same size and household composition. Just over one-half of all food-insecure households participated in one or more of the three largest Federal food assistance programs during the month prior to the survey.Food security, food insecurity, hunger, food pantry, emergency kitchen, material well-being, Food Stamp Program, National School Lunch Program, WIC, Food Security and Poverty,

HOUSEHOLD FOOD SECURITY IN THE UNITED STATES, 2001

Eighty-nine percent of American households were food secure throughout the entire year 2001. The rest were food insecure at least some time during the year, meaning they did not always have access to enough food for active, healthy lives for all household members because they lacked sufficient money or other resources for food. The prevalence of food insecurity rose from 10.1 percent in 1999 to 10.7 percent in 2001, and the prevalence of food insecurity with hunger rose from 3.0 percent to 3.3 percent during the same period. This report, based on data from the December 2001 food security survey, provides the most recent statistics on the food security of U.S. households, as well as on how much they spent for food and the extent to which food-insecure households participated in Federal and community food assistance programs. Survey responses indicate that the typical food-secure household in the United States spent 32 percent more than the typical food-insecure household of the same size and household composition. About one-half of all food-insecure households participated in one or more of the three largest Federal food assistance programs during the month prior to the survey. About 19 percent of food-insecure households 2.8 percent of all U.S. households obtained emergency food from a food pantry at some time during the year.Food security, food insecurity, hunger, food spending, food pantry, soup kitchen, emergency kitchen, material well-being, Food Stamp Program, National School Lunch Program, WIC, Food Security and Poverty,

HOUSEHOLD FOOD SECURITY IN THE UNITED STATES, 2002

Eighty-nine percent of American households were food secure throughout the entire year 2002, meaning that they had access, at all times, to enough food for an active, healthy life for all household members. The remaining households were food insecure at least some time during that year. The prevalence of food insecurity rose from 10.7 percent in 2001 to 11.1 percent in 2002, and the prevalence of food insecurity with hunger rose from 3.3 percent to 3.5 percent. This report, based on data from the December 2002 food security survey, provides the most recent statistics on the food security of U.S. households, as well as on how much they spent for food and the extent to which food-insecure households participated in Federal and community food assistance programs. Survey responses indicate that the typical food-secure household in the U.S. spent 35 percent more on food than the typical food-insecure household of the same size and household composition. Just over one-half of all food-insecure households participated in one or more of the three largest Federal food assistance programs during the month prior to the survey. About 19 percent of food-insecure households3.0 percent of all U.S. householdsobtained emergency food from a food pantry at some time during the year.Food security, food insecurity, hunger, food spending, food pantry, soup kitchen, emergency kitchen, material well-being, Food Stamp Program, National School Lunch Program, WIC, Food Security and Poverty,