An analysis of a large scale habitat monitoring application

Habitat and environmental monitoring is a driving application for wireless sensor networks. We present an analysis of data from a second generation sensor networks deployed during the summer and autumn of 2003. During a 4 month deployment, these networks, consisting of 150 devices, produced unique datasets for both systems and biological analysis. This paper focuses on nodal and network performance, with an emphasis on lifetime, reliability, and the the static and dynamic aspects of single and multi-hop networks. We compare the results collected to expectations set during the design phase: we were able to accurately predict lifetime of the single-hop network, but we underestimated the impact of multihop traffic overhearing and the nuances of power source selection. While initial packet loss data was commensurate with lab experiments, over the duration of the deployment, reliability of the backend infrastructure and the transit network had a dominant impact on overall network performance. Finally, we evaluate the physical design of the sensor node based on deployment experience and a post mortem analysis. The results shed light on a number of design issues from network deployment, through selection of power sources to optimizations of routing decisions

A Vehicle for Research: Using Street Sweepers to Explore the Landscape of Environmental Community Action

Researchers are developing mobile sensing platforms to facilitate public awareness of environmental conditions. However, turning such awareness into practical community action and political change requires more than just collecting and presenting data. To inform research on mobile environmental sensing, we conducted design fieldwork with government, private, and public interest stakeholders. In parallel, we built an environmental air quality sensing system and deployed it on street sweeping vehicles in a major U.S. city; this served as a "research vehicle" by grounding our interviews and affording us status as environmental action researchers. In this paper, we present a qualitative analysis of the landscape of environmental action, focusing on insights that will help researchers frame meaningful technological interventions.Comment: 10 page

Climatic influences on needle cohort survival mediated by Swiss needle cast in coastal Douglas-fir

Abstract Swiss needle cast (SNC) severity in Douglas-fir (Pseudotsuga menziesii) has been shown to vary spatially and temporally in response to climatic factors both within its native range and in regions where it has been planted as an exotic species. Survival models were developed for different Douglas-fir needle cohorts to enhance our understanding of how climatic influences on needle longevity are mediated by SNC in the Oregon Coast Range. The climate-based models were based on repeated measurement of 100 plots between 1998 and 2005 coupled with downscaled PRISM climate data. Potential predictors of needle survival by annual cohort were selected from numerous climatic variables at annual, seasonal, and monthly scales. Needle survival probability was positively associated with maximum summer temperature, and negatively associated with minimum winter temperature and spring precipitation. Seasonal climate variables associated with needle longevity are consistent with current epidemiological understanding of Phaeocyrptopus gaeumannii, as well as with previous analyses of climatic influences on SNC severity as measured by average years of foliage retention and frequency of fungal fruiting bodies, or pseudothecia, in stomates

Climatic influences on needle cohort survival mediated by Swiss needle cast in coastal Douglas-fir

Swiss needle cast (SNC) severity in Douglas-fir (Pseudotsuga menziesii) has been shown to vary spatially and temporally in response to climatic factors both within its native range and in regions where it has been planted as an exotic species. Survival models were developed for different Douglas-fir needle cohorts to enhance our understanding of how climatic influences on needle longevity are mediated by SNC in the Oregon Coast Range. The climate-based models were based on repeated measurement of 100 plots between 1998 and 2005 coupled with downscaled PRISM climate data. Potential predictors of needle survival by annual cohort were selected from numerous climatic variables at annual, seasonal, and monthly scales. Needle survival probability was positively associated with maximum summer temperature, and negatively associated with minimum winter temperature and spring precipitation. Seasonal climate variables associated with needle longevity are consistent with current epidemiological understanding of Phaeocyrptopus gaeumannii, as well as with previous analyses of climatic influences on SNC severity as measured by average years of foliage retention and frequency of fungal fruiting bodies, or pseudothecia, in stomates.Keywords: cohort survival, climatic effects, survival probability., needle longevit

Thinning Mixed-Species Stands of Douglas-Fir and Western Hemlock in the Presence of Swiss Needle Cast: Guidelines Based on Relative Basal Area Growth of Individual Trees

In coastal forests of the Pacific Northwest, young coniferous plantations typically contain a mixture of planted and natural Douglas-fir (Pseudotsuga menziesii) and western hemlock (Tsuga heterophylla). Swiss needle cast (SNC) disease inhibits the growth of Douglas-fir to varying degrees in these stands, depending on SNC severity. In addition to the value differential between Douglas-fir and western hemlock, foresters must account for differences in growth potential (tree size, competitive position, site characteristics, disease pressure) when selecting trees for retention during thinning operations. Diameter increment models for Douglas-fir and western hemlock were developed from permanent plot data collected for the SNC growth impact study (GIS), Precommercial Thinning Study (PCT), Commercial Thinning Study (CT), and Retrospective Commercial Thinning Study (RCT). Predictor variables represent tree size, competitive position, site characteristics, and SNC severity. SNC severity was indexed by foliage retention, defined as the number of annual needle cohorts held by a tree. Foliage retention was positively correlated with Douglas-fir diameter increment and negatively correlated with western hemlock diameter increment. Charts developed from the diameter growth models provide a field tool for assessing the relative basal area growth of adjacent Douglas-fir and western hemlock of a given initial diameter in a stand of given SNC severity. In a stand with severe SNC (foliage retention=1.5 years) the basal area growth of a 6-inch western hemlock tree will exceed the basal area growth of any Douglas-fir tree up to 7.7 inches in DBH. In a relatively healthy stand (foliage retention=3.0 years) the basal area growth of 6-inch Douglas-fir and western hemlock trees will be approximately equivalent.Keywords: Relative growth, Basal area increment, Disease severity, Thinning guidelines, Foliage retentio

CMMD: Active Messages on the CM-5

: Active messages provide an important new communication primitive for building message passing systems. CMMD, the message passing system of the CM-5, uses active messages as a basic substrate for constructing multiple, low overhead, communication paradigms. Examples are also given which show how developers may incorporate active messages in application-specific ways. KEYWORDS: Message passing, active messages, massively parallel systems 1. Introduction The current generation of distributed-memory massively parallel systems stand in marked contrast to systems of only a few years ago. Hardware advancements have brought improved floating point performance and communication rates. Node-to-node network latencies are now in the microsecond range and bandwidths range from the tens to hundreds of megabytes per second. Message passing libraries and compilers for parallel languages alike benefit from improved communication performance. However, as network latencies decrease and bandwidths inc..