Achieving Dilution without Knowledge of Coordinates in the SINR Model

Considerable literature has been developed for various fundamental distributed problems in the SINR (Signal-to-Interference-plus-Noise-Ratio) model for radio transmission. A setting typically studied is when all nodes transmit a signal of the same strength, and each device only has access to knowledge about the total number of nodes in the network $n$, the range from which each node's label is taken $[1,\dots,N]$, and the label of the device itself. In addition, an assumption is made that each node also knows its coordinates in the Euclidean plane. In this paper, we create a technique which allows algorithm designers to remove that last assumption. The assumption about the unavailability of the knowledge of the physical coordinates of the nodes truly captures the `ad-hoc' nature of wireless networks. Previous work in this area uses a flavor of a technique called dilution, in which nodes transmit in a (predetermined) round-robin fashion, and are able to reach all their neighbors. However, without knowing the physical coordinates, it's not possible to know the coordinates of their containing (pivotal) grid box and seemingly not possible to use dilution (to coordinate their transmissions). We propose a new technique to achieve dilution without using the knowledge of physical coordinates. This technique exploits the understanding that the transmitting nodes lie in 2-D space, segmented by an appropriate pivotal grid, without explicitly referring to the actual physical coordinates of these nodes. Using this technique, it is possible for every weak device to successfully transmit its message to all of its neighbors in $\Theta(\lg N)$ rounds, as long as the density of transmitting nodes in any physical grid box is bounded by a known constant. This technique, we feel, is an important generic tool for devising practical protocols when physical coordinates of the nodes are not known.Comment: 10 page

Advanced flight control system study

The architecture, requirements, and system elements of an ultrareliable, advanced flight control system are described. The basic criteria are functional reliability of 10 to the minus 10 power/hour of flight and only 6 month scheduled maintenance. A distributed system architecture is described, including a multiplexed communication system, reliable bus controller, the use of skewed sensor arrays, and actuator interfaces. Test bed and flight evaluation program are proposed

An Archaeological Survey of the Proposed Location of the Bastrop City Wastewater Treatment Plant, Bastrop County, Texas

Between August 11 and August 13, 2004, the Center for Archaeological Research at The University of Texas at San Antonio conducted an archaeological survey of the proposed location for the City of Bastrop Wastewater Treatment Plant in central Bastrop County, Texas. The pedestrian survey was performed for Raba-Kistner Consultants, Inc. on behalf of the City of Bastrop. Construction of the proposed wastewater treatment facility will primarily impact the northwestern portion of the property, although a gray-water outfall line will traverse the property and empty into the Colorado River. The survey, carried out under Texas Antiquities Permit No. 3501 with Dr. Steve A. Tomka serving as Principal Investigator, was performed to identify any cultural deposits present within the project area. The Phase 1 project included a 100% pedestrian survey of the 26.5-acre property, the excavation of 27 shovel tests, and the excavation of seven backhoe trenches. Two archaeological sites, both located on the southern portion of the project area, were identified. Site 41BP678, located at the confluence of the Colorado River and a tributary, Spring Branch, consists of a light surface scatter of chipped stone debitage and buried cultural materials. The results of shovel testing suggest that two components may be present, with one located from the surface down to 20 cm, and a second located between 40 cm and 60 cm below surface. No features were identified, though burned rock is present in small numbers. No temporally diagnostic artifacts were recovered. The second site, 41BP679, abuts Spring Branch. This site consists of a light surface scatter of chipped stone, minimally including a biface and a core. Shovel testing demonstrates that debitage and burned rock is present down to 30 cm below surface, though deeper deposits (ca. 75 cm to 92 cm below surface), evidenced by two flakes present in a backhoe trench profile, are present at the site. No features were identified at 41BP679. While no diagnostic artifacts were recovered, a broken biface was collected from the backdirt of a backhoe trench. The highly patinated biface has parallel flaking reminiscent of late Paleoindian (c.f. Angostura) forms. The proposed wastewater treatment facility will impact limited portions of each of these sites. The gray-water outflow line will cut through roughly 109 m of 41BP678, and 61 m of 41BP679. In addition, the construction of one clarifier tank and a flume will directly impact small portions of 41BP679. We currently lack sufficient information on either site to make determinations of eligibility for listing on the National Register of Historic Places or for determining State Archeological Landmark status. If the proposed wastewater treatment facility cannot be moved to avoid these sites, we recommend that limited testing be conducted to determine the eligibility status of 41BP678 and 41BP679. All artifacts collected during this project are curated at the Center for Archaeological Research according to Texas Historical Commission guidelines

Comparative study of infant and child mortality: The case of Kenya and South Africa

Comparisons of infant and child mortality between populations, both within and between countries, are important because they highlight causative factors of mortality, which can be addressed by health policies and programmes seeking to reduce high mortality at the young ages. Such information is useful for demographic assessment of the population and the evaluation of health policies and programmes. This study undertakes a comparative analysis of neonatal, post-neonatal and child mortality using the 1998 South African Demographic and Health Survey and the 2003 Kenya Demographic and Health Survey. Two methods of analysis are used in this study. First variations in infant and child mortality levels by population groups are investigated through bivariate analysis which forms the basis for the logistic analysis. The results from the bivariate analysis show the existence of linkages between mother’s and partner’s levels of education, literacy, urban/rural place of residence, ethnicity, birth order, age of mother at the time of birth of child, age of mother at first marriage, mother’s occupation, water supply and health facilities and their children’s survival chances. Logistic analysis revealed that ethnicity, type of toilet facilities, literacy and birth order explain most of the variations in infant and child mortality in Kenya while mother’s educational attainment and type of toilet facilities were the main variables of importance for South Africa. These findings have important implications on efforts to reduce gaps in mortality differentials. For example the existing socio-economic and demographic differentials in infant and child mortality in the two countries can be reduced through provision of equitable high quality education, proper sanitation, discouragement of early marriage and early childbearing among others

Nutrient And Contaminant Dynamics In The Marine Food Web Of Kotzebue Sound (Alaska)

Thesis (Ph.D.) University of Alaska Fairbanks, 2010The objectives of these studies were to document nutrient and contaminant concentrations in upper trophic level organisms of the Kotzeue, Alaska marine food web; address associated risks and benefits to human consumers of these species; understand the drivers of nutrient and contaminant patterns and concentrations; and test the limitations of chemical feeding ecology tools used to trace nutrient and contaminant pathways within this food web. Tissues of subsistence harvested animals were analyzed for nutrients, contaminants and stable isotopes (delta13C and delta15N). Foods derived from sheefish (Stenodus leucicthys) and spotted seal (Phoca largha) provide numerous essential nutrients, with limited risk from contaminant exposure. Food processing altered nutrient and contaminant concentrations and stable isotope ratios, warranting the evaluation of foods as they are ultimately consumed when determining the risks and benefits of traditional diets. delta13C and delta15N, common chemical tracers of feeding ecology and contaminant pathways in food webs, varied widely by tissue type. delta15N and mercury did not differ consistently among seal tissues. Consequently, when utilizing stable isotopes as tracers of feeding ecology and mercury exposure, the specific tissue consumed and the processed state of the tissue should be considered. Bioaccumulation patterns differed between sheefish and spotted seals in relation to their respiratory physiology and persistent organic pollutant (POP) partitioning behavior between lipids and the respiratory medium (i.e., air versus water). Certain POPs that do not bioaccumulate in fish due to rapid excretion across the gills into surrounding waters (low KOW) do bioaccumulate in seals if not efficiently eliminated via the lungs to the air (high K OA). Thus, KOW alone cannot predict bioaccumulation in mammals. Regulatory guidelines must incorporate KOA into chemical risk-assessments for air-breathing species, including humans and marine mammals. Ringed ( Phoca hispida), spotted and bearded (Erignathus barbatus ) seals had distinct blubber fatty acid (FA) signatures. Blubber of ringed and spotted seals exhibited significant stratification relative to both FA degree of unsaturation and carbon chain length. FA stratification appears largely driven by the steep temperature gradient of blubber, except in the case of polyunsaturated FA (PUFA) which may be maintained in the inner blubber for rapid mobilization to meet physiological requirements

Real-time decoding of question-and-answer speech dialogue using human cortical activity.

Natural communication often occurs in dialogue, differentially engaging auditory and sensorimotor brain regions during listening and speaking. However, previous attempts to decode speech directly from the human brain typically consider listening or speaking tasks in isolation. Here, human participants listened to questions and responded aloud with answers while we used high-density electrocorticography (ECoG) recordings to detect when they heard or said an utterance and to then decode the utterance's identity. Because certain answers were only plausible responses to certain questions, we could dynamically update the prior probabilities of each answer using the decoded question likelihoods as context. We decode produced and perceived utterances with accuracy rates as high as 61% and 76%, respectively (chance is 7% and 20%). Contextual integration of decoded question likelihoods significantly improves answer decoding. These results demonstrate real-time decoding of speech in an interactive, conversational setting, which has important implications for patients who are unable to communicate