@article{zhang_hughes-oliver_ng_2009, title={A Model-Based Ensembling Approach for Developing QSARs}, volume={49}, ISSN={["1549-960X"]}, DOI={10.1021/ci900080f}, abstractNote={Ensemble methods have become popular for QSAR modeling, but most studies have assumed balanced data, consisting of approximately equal numbers of active and inactive compounds. Cheminformatics data are often far from being balanced. We extend the application of ensemble methods to include cases of imbalance of class membership and to more adequately assess model output. Based on the extension, we propose an ensemble method called MBEnsemble that automatically determines the appropriate tuning parameters to provide reliable predictions and maximize the F-measure. Results from multiple data sets demonstrate that the proposed ensemble technique works well on imbalanced data.}, number={8}, journal={JOURNAL OF CHEMICAL INFORMATION AND MODELING}, author={Zhang, Qianyi and Hughes-Oliver, Jacqueline M. and Ng, Raymond T.}, year={2009}, month={Aug}, pages={1857–1865} }
 @article{renwick_vanni_zhang_patton_2008, title={Water quality trends and changing agricultural practices in a Midwest US watershed, 1994-2006}, volume={37}, ISSN={["1537-2537"]}, DOI={10.2134/jeq2007.0401}, abstractNote={Sediment and nutrient concentrations in surface water in agricultural regions are strongly influenced by agricultural activities. In the Corn Belt, recent changes in farm management practices are likely to affect water quality, yet there are few data on these linkages at the landscape scale. We report on trends in concentrations of N as ammonium (NH4) and nitrate (NO3), soluble reactive phosphorus (SRP), and suspended sediment (SS) in three Corn Belt streams with drainage areas of 12 to 129 km2 for 1994 through 2006. During this period, there has been an increase in conservation tillage, a decline in fertilizer use, and consolidation of animal feeding operations in our study watersheds and throughout the Corn Belt. We use an autoregressive moving average model to include the effects of discharge and season on concentrations, LOWESS plots, and analyses of changes in the relation between discharge and concentration. We found significant declines in mean monthly concentrations of NH4 at all three streams over the 13‐yr period, declines in SRP and SS in two of the three streams, and a decline in NO3 in one stream. When trend coefficients are converted to percent per year and weighted by drainage, area changes in concentration are −8.5% for NH4, −5.9% for SRP, −6.8% for SS, and −0.8% for NO3 Trends in total N and P are strongly tied to trends in NO3, SRP, and SS and indicate that total P is declining, whereas total N is not.}, number={5}, journal={JOURNAL OF ENVIRONMENTAL QUALITY}, author={Renwick, William H. and Vanni, Michael J. and Zhang, Qianyi and Patton, Jon}, year={2008}, pages={1862–1874} }