Browsing by Subject "Differential"
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Item A reachability problem for the Heisenberg group(Texas Tech University, 1999-08) Follis, Jack L.The reachability problem is a control system problem on a given manifold. Taking the three-dimensional Heisenberg group as our manifold with certain controls placed on a system, we want to know what sets of point on the manifold one can reach. In (jrder to do this, the basic form of a horizontal vector on a principal bundle over the manifold needs to be calculated. By generating a Lie algebra, using horizontal vectors on a principal bundle the reachable set of the system can be found.Item Codebook ordering for vector quantization(Texas Tech University, 2003-12) Ye, Linning; Mitra, Sunanda; Nutter, Brian; Karp, TanjaAddress predictive vector quantization (APVQ) utilizes an ordered codebook to exploit the dependency among close input vectors. The Kohonen algorithm is often chosen in APVQ. However, the Kohonen algorithm is not applicable while a codebook already exists. In this thesis three methods of ordering an existing codebook have been developed. Theoretically these codebook ordering methods can be utilized in any vector quantization in order to reduce the output bit rate. Here we apply it to two types of vector quantization approaches, geometric vector quantization (GVQ) and vector quantization based on the LBG algorithm. The results of codebook ordering on vector quantization based on the LBG algorithm are quite good. However, codebook ordering does not have good performance on GVQ. Therefore, while applying codebook ordering to one specific VQ, we should consider the property of this VQ in order to achieve a satisfactory result.Item Diagnostic accuracy in motor speech disorders: an application of signal detection theory(Texas Tech University, 2004-05) Whitaker, Melissa C.; Bogschutz, Renee J.; Schmitt, Mary B.; Aoyama, Kastura; Corwin, Melinda D.The results of this study indicated that participants accurately and reliably differentiated normal from abnormal speech samples. Thus, all groups proficiently identified disordered cases while limiting the number of misdiagnoses; however, some degree of task difficulty was noted and clinical biases were evident. For this research question, group trends indicated that the most experienced group of participants adopted a more lenient diagnostic criterion as compared to the intermediate and novice groups.Item A fundamental approximation in MATLAB of the efficiency of an automotive differential in transmitting rotational kinetic energy(2012-05) Vaughn, James Roy; Matthews, Ronald D.; Bryant, Michael D.The VCOST budgeting tool uses a drive cycle simulator to improve fuel economy predictions for vehicle fleets. This drive cycle simulator needs to predict the efficiency of various components of the vehicle's powertrain including any differentials. Existing differential efficiency models either lack accuracy over the operating conditions considered or require too great an investment. A fundamental model for differential efficiency is a cost-effective solution for predicting the odd behaviors unique to a differential. The differential efficiency model itself combines the torque balance equation and the Navier-Stokes equations with models for gear pair, bearing, and seal efficiencies under a set of appropriate assumptions. Comparison of the model with existing data has shown that observable trends in differential efficiency are reproducible in some cases to within 10% of the accepted efficiency value over a range of torques and speeds that represents the operating conditions of the differential. Though the model is generally an improvement over existing curve fits, the potential exists for further improvement to the accuracy of the model. When the model performs correctly, it represents an immense savings over collecting data with comparable accuracy.