The Purdue PSE Kernel: Towards a kernel for building PSEs

Abstract Problem Solvillg Environments (PSEs

Co-limitation towards lower latitudes shapes global forest diversity gradients

The latitudinal diversity gradient (LDG) is one of the most recognized global patterns of species richness exhibited across a wide range of taxa. Numerous hypotheses have been proposed in the past two centuries to explain LDG, but rigorous tests of the drivers of LDGs have been limited by a lack of high-quality global species richness data. Here we produce a high-resolution (0.025° × 0.025°) map of local tree species richness using a global forest inventory database with individual tree information and local biophysical characteristics from ~1.3 million sample plots. We then quantify drivers of local tree species richness patterns across latitudes. Generally, annual mean temperature was a dominant predictor of tree species richness, which is most consistent with the metabolic theory of biodiversity (MTB). However, MTB underestimated LDG in the tropics, where high species richness was also moderated by topographic, soil and anthropogenic factors operating at local scales. Given that local landscape variables operate synergistically with bioclimatic factors in shaping the global LDG pattern, we suggest that MTB be extended to account for co-limitation by subordinate drivers

Integrated Symbolic-Numeric Computing in //ELLPACK: Experiences and Plans

In this paper we describe the use of integrated symbolic--numeric computing techniques in the evolving //ELLPACK 1 [HRC + 90] Problem Solving Environment. //ELLPACK is a problem solving environment (PSE) for solving partial differential equations (PDEs) using parallel architectures. It was originally developed to use the ELLPACK[RB85] system as the numerical computing engine. The domain of applicability of ELLPACK is restricted to second order linear elliptic boundary value problems in two and three dimensions. We apply hybrid symbolic--numeric techniques to extend the domain of applicability of the //ELLPACK PSE using both ELLPACK and other numerical PDE solving systems as numerical engines. These techniques have been implemented as an interactive tool using the X Window System[SG86]. Once the PDE problem is specified, it is symbolically manipulated using the MAXIMA 2 computer algebra system to generate a //ELLPACK program to solve the problem using either ELLPACK or FIDISOL[SSM..

A Stream Database Server for Sensor Applications

We present a framework for stream data processing that incorporates a stream database server as a fundamental component. The server operates as the stream control interface between arrays of distributed data stream sources and end-user clients that access and analyze the streams. The underlying framework provides novel stream management and query processing mechanisms to support the online acquisition, management, storage, non-blocking query, and integration of data streams for distributed multi-sensor networks. In this paper, we define our stream model and stream representation for the stream database, and we describe the functionality and implementation of key components of the stream processing framework, including the query processing interface for source streams, the stream manager, the stream buffer manager, nonblocking query execution, and a new class of join algorithms for joining multiple data streams constrained by a sliding time window. We conduct experiments using real data streams to evaluate the performance of the new algorithms against traditional stream join algorithms. The experiments show significant performance improvements and also demonstrate the flexibility of our system in handling data streams. A multi-sensor network application for the intelligent detection of hazardous materials is presented to illustrate the capabilities of our framework

On the Software Engineering of Multi-Platform Parallel/Distributed Software

This paper describes our experience in developing and maintaining multi-platform parallel / distributed scientific computing software. We gained this experience while developing the parallel computation environment for //ELLPAC