Decline in the Index of Biotic Integrity of the Fish Assemblage as a Response to Reservoir Aging

The fish assemblage from reservoir Medjuvrsje was monitored over the 1955–2000 period. The Medjuvrsje Reservoir is one of the oldest Serbian reservoirs formed in 1953. Ichthyofauna was sampled in 1955, 1984, 1991 and 2000. Modified index of biotic integrity (IBI) metrics were used to assess changes in biotic integrity. The relative abundance of omnivorous, phytophilic and tolerant species increased, that of lithophilic, intolerant and rheophilic species decreasing during the 45 years. The total IBI decreased from 44 in 1955 to 24 in 2000, while the sediment deposition rate increased from 26.8% in 1963 to 70.4% in 2005. There was a significant negative correlation between the IBI and the sediment deposition rate. This study showed that the IBI could be used to characterize the status of the reservoir.     

Coherency recognition using epsilon decomposition

This paper proposes a new algorithm for the identification of coherent generators, which is based on epsilon decompositions of the Jacobian. By using the Jacobian, the algorithm overcomes some major drawbacks of other methods for coherency recognition; in addition, it can be directly integrated into programs for transient stability analysis. Test results on a 48 machine system are presented to evaluate the method     

SPIRAL: Code Generation for DSP Transforms

Fast changing, increasingly complex, and diverse computing platforms pose central problems in scientific computing: How to achieve, with reasonable effort, portable optimal performance? We present SPIRAL, which considers this problem for the performance-critical domain of linear digital signal processing (DSP) transforms. For a specified transform, SPIRAL automatically generates high-performance code that is tuned to the given platform. SPIRAL formulates the tuning as an optimization problem and exploits the domain-specific mathematical structure of transform algorithms to implement a feedback-driven optimizer. Similar to a human expert, for a specified transform, SPIRAL "intelligently" generates and explores algorithmic and implementation choices to find the best match to the computer's microarchitecture. The "intelligence" is provided by search and learning techniques that exploit the structure of the algorithm and implementation space to guide the exploration and optimization. SPIRAL generates high-performance code for a broad set of DSP transforms, including the discrete Fourier transform, other trigonometric transforms, filter transforms, and discrete wavelet transforms. Experimental results show that the code generated by SPIRAL competes with, and sometimes outperforms, the best available human tuned transform library code.