Purdue University

About: Purdue University is a education organization based out in West Lafayette, Indiana, United States. It is known for research contribution in the topics: Population & Context (language use). The organization has 73219 authors who have published 163563 publications receiving 5775236 citations. The organization is also known as: Purdue & Purdue-West Lafayette.

Identifying mislabeled training data

Abstract: This paper presents a new approach to identifying and eliminating mislabeled training instances for supervised learning. The goal of this approach is to improve classification accuracies produced by learning algorithms by improving the quality of the training data. Our approach uses a set of learning algorithms to create classifiers that serve as noise filters for the training data. We evaluate single algorithm, majority vote and consensus filters on five datasets that are prone to labeling errors. Our experiments illustrate that filtering significantly improves classification accuracy for noise levels up to 30%. An analytical and empirical evaluation of the precision of our approach shows that consensus filters are conservative at throwing away good data at the expense of retaining bad data and that majority filters are better at detecting bad data at the expense of throwing away good data. This suggests that for situations in which there is a paucity of data, consensus filters are preferable, whereas majority vote filters are preferable for situations with an abundance of data.

Introduction to the Thermodynamics of Materials

Abstract: Preface. Introduction and Definition of Terms. The First Law of Thermodynamics. The Second Law of Thermodynamics. The Statistical Interpretation of Entropy. Auxiliary Functions. Heat Capacity, Enthalpy, Entropy, and the Third Law of Thermodynamics. Phase Equilibrium in a One-Component System. The Behavior of Gases. The Behavior of Solutions. Gibbs Free Energy-Composition and Phase Diagrams of Binary Systems. Reactions Involving Gases. Reactions Involving Pure Consensed Phases and a Gaseous Phase. Reaction Equilibria in Systems Containing Components in Condensed Solutions. Phase Diagrams for Binary Systems in Pressure-Temperature-Composition Space. Electrochemistry. Appendix A: Selected Thermodynamic and Thermochemical Data. Appendix B Exact Differential Equations. Appendix C The Generation of Auxiliary Functions as Legendre Transformations. Nomenclatures. Answers. Index.

A diffuse-interface method for simulating two-phase flows of complex fluids

Abstract: Two-phase systems of microstructured complex fluids are an important class of engineering materials. Their flow behaviour is interesting because of the coupling among three disparate length scales: molecular or supra-molecular conformation inside each component, mesoscopic interfacial morphology and macroscopic hydrodynamics. In this paper, we propose a diffuse-interface approach to simulating the flow of such materials. The diffuse-interface model circumvents certain numerical difficulties in tracking the interface in the classical sharp-interface description. More importantly, our energy-based variational formalism makes it possible to incorporate complex rheology easily, as long as it is due to the evolution of a microstructure describable by a free energy. Thus, complex rheology and interfacial dynamics are treated in a unified framework. An additional advantage of our model is that the energy law of the system guarantees the existence of a solution. We will outline the general approach for any two-phase complex fluids, and then present, as an example, a detailed formulation for an emulsion of nematic drops in a Newtonian matrix. Using spectral discretizations, we compute shear-induced deformation, head-on collision and coalescence of drops where the matrix and drop phases are Newtonian or viscoelastic Oldroyd-B fluids. Numerical results are compared with previous studies as a validation of the theoretical model and numerical code. Finally, we simulate the retraction of an extended nematic drop in a Newtonian matrix as a method for measuring interfacial tension.

Client Importance, Nonaudit Services, and Abnormal Accruals

Abstract: The economic theory of auditor independence (DeAngelo 1981b) suggests that auditors' incentives to compromise their independence are related to client importance. Using ratios of client fees and of nonaudit fees divided by the audit firm's U.S. revenues or a surrogate for the audit‐practice‐office revenues as measures of client importance, we investigate their association with Jones‐model abnormal accruals. In a sample of 1,871 clients of Big 5 audit firms we do not find a statistically significant association between abnormal accruals and any of the client importance measures. Our theory development also suggests that auditor incentives to compromise independence should increase with the extent of client opportunities and incentives to manage earnings, and decrease with the strength of corporate governance and auditor expertise. We also do not find a statistically significant association between abnormal accruals and client importance in subsets of the samples partitioned by proxies for these factors.