Browsing by Author "Christopher Healey, Committee Member"
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- Algorithms for Selecting Views and Indexes to Answer Queries(2009-07-22) Kormilitsin, Maxim; Christopher Healey, Committee Member; Yahya Fathi, Committee Member; Matthias Stallmann, Committee Co-Chair; Rada Chirkova, Committee ChairIn many contexts it is beneﬠcial to answer database queries using derived data called views. Using views in query answering is relevant in applications in information integration, data warehousing, web-site design, and query optimization. The problem of answering queries using views can be divided into a number of subproblems. The ﬠrst step in the process of view selection is to identify which view can be used to answer queries from the given set. The second step is to determine possible reformulations of the workload queries. The last step is choosing views that can be maintained appropriately and that minimize the processing time of the input query workload. In our work we address the problem of selecting and precomputing indexes and materialized views in a database system, with the goal of improving the processing performance for frequent and important queries. The focus of our work is to develop a uniﬠed quality-centered view- and index-selection approach, for a range of query, view, and index classes that are typical in practical database systems. To the best of our knowledge, we are the ﬠrst to adopt the solution-quality focus for this generic practical problem setting.
- Development of a Haptic-based Rey-Osterrieth Complex Figure Testing and Training System with Computer Scoring and Force-feedback Rehabilitation Functions.(2010-05-06) Li, Yingjie; David Kaber, Committee Chair; Yuan-Shin Lee, Committee Chair; Christopher Healey, Committee Member; Simon Hsiang, Committee Member; Larry Tupler, Committee Member; Robert St. Amant, Committee Member
- Hierarchical Charged Particle Filter for Multiple Target Tracking.(2010-11-10) Bhatia, Amit; Griff Bilbro, Committee Chair; Wesley Snyder, Committee Chair; Christopher Healey, Committee Member; Robert St. Amant, Committee Member
- Iterative Multi-Bounce Global Illumination Through Brute-Force Rasterization-Based Sampling.(2010-12-17) Fonseca, Alejandro; Benjamin Watson, Committee Chair; Christopher Healey, Committee Member; Robert Young, Committee Member
- ParaFitter: Automatic Runtime Concurrency Configuration for Parallel Scientific Applications(2007-07-15) Tetterton, James Cornelius; David Lalush, Committee Member; Xiaosong Ma, Committee Chair; Christopher Healey, Committee Member
- Virtual Sculpting and Polyhedral Machining Planning System with Haptic Interface(2004-10-31) Zhu, Weihang; Christopher Healey, Committee Member; Robert Young, Committee Member; Ezat Sanii, Committee Member; Yuan-Shin Lee, Committee ChairThis research proposes the methodology of a novel haptic sculpting and machining planning system for virtual prototyping and manufacturing. A lab-built 6-DOF (degree of freedom) input and 5-DOF output haptic interface system is utilized in the proposed haptic sculpting and machining planning system. A dexel-based haptic virtual prototyping CAD system and a triangulated surface-based machining planning (manufacturing) system are developed. A dexel-based collision detection method and a force-torque feedback analysis are proposed for virtual prototyping module. The output of the virtual prototyping module can be either STL polyhedral surface model, or the tool motion, which is recorded as NC (numerically-controlled) commands. Haptic interface is also used in the machining planning to help determine the feasible tool orientation for 5-axis NC tool path generation. A new machining strategy of 5-axis pencil-cut machining is proposed with the haptic interface. An OBB (object bounding box)-tree and point-cloud-based Two-phase collision detection and force-torque feedback algorithm are proposed for virtual manufacturing module. Dexel-based method is developed for global tool interference avoidance with other components in a complex machining environment. To bridge the virtual prototyping module and machining planning module, a conversion marching algorithm is proposed to construct STL surface models from Dexel volume models. The algorithm can be used in both virtual prototyping system and NC simulation and verification. In the virtual sculpting module, a user can virtually sculpt a stock volume material intuitively by the haptic interface system. Hardware and software implementations of the haptic sculpting and machining planning system are also presented in this paper. The proposed methodology and developed haptic sculpting and machining planning system can be used in CAD/CAM systems and virtual prototyping.
