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Ravi Gummadi Anupam Khulbe Aravind Kalavagattu Sanil Salvi Subbarao Kambhampati 《Journal of Intelligent Information Systems》2012,38(3):575-599
Many web databases can be seen as providing partial and overlapping information about entities in the world. To answer queries effectively, we need to integrate the information about the individual entities that are fragmented over multiple sources. At first blush this is just the inverse of traditional database normalization problem—rather than go from a universal relation to normalized tables, we want to reconstruct the universal relation given the tables (sources). The standard way of reconstructing the entities will involve joining the tables. Unfortunately, because of the autonomous and decentralized way in which the sources are populated, they often do not have Primary Key–Foreign Key relations. While tables may share attributes, naive joins over these shared attributes can result in reconstruction of many spurious entities thus seriously compromising precision. Our system, SmartInt is aimed at addressing the problem of data integration in such scenarios. Given a query, our system uses the Approximate Functional Dependencies (AFDs) to piece together a tree of relevant tables to answer it. The result tuples produced by our system are able to strike a favorable balance between precision and recall. 相似文献
64.
This paper presents a new algorithm for extracting Free-Form Surface Features (FFSFs) from a surface model. The extraction algorithm is based on a modified taxonomy of FFSFs from that proposed in the literature. A new classification scheme has been proposed for FFSFs to enable their representation and extraction. The paper proposes a separating curve as a signature of FFSFs in a surface model. FFSFs are classified based on the characteristics of the separating curve (number and type) and the influence region (the region enclosed by the separating curve). A method to extract these entities is presented. The algorithm has been implemented and tested for various free-form surface features on different types of free-form surfaces (base surfaces) and is found to correctly identify and represent the features irrespective of the type of underlying surface. The representation and extraction algorithm are both based on topology and geometry. The algorithm is data-driven and does not use any pre-defined templates. The definition presented for a feature is unambiguous and application independent. The proposed classification of FFSFs can be used to develop an ontology to determine semantic equivalences for the feature to be exchanged, mapped and used across PLM applications. 相似文献
65.
R. Ravi Y. V. R. K. Prasad V. V. S. Sarma R. S. Raidu 《Materials and Manufacturing Processes》2006,21(8):756-760
Processing maps are developed using the Dynamic Materials Model (DMM) and instability criterion, which help in choosing optimum process parameters for hot-working of materials. Certain high-level expertise is required to interpret and extract the information on instability regimes to be avoided during processing. In recent years, Artificial Neural Network (ANN) models have been developed to predict flow stress by using the input vector; namely, temperature, strain rate and strain. In this study, using the available Cu-Zn alloy data, ANN model has been developed to classify the hot-working process parameters, such as temperature, strain rate and flow stress for instability regime, directly from the corrected flow stress data without applying the DMM. This model uses 10 compositions of Cu-Zn system, ranging from 3% Zn to 51% Zn. The developed ANN model has been able to learn the nonlinear classifier, which separates unstable region from the stable region in the Cu-Zn alloy system with zinc content less than 40%. 相似文献
66.
Integrated starter generator for 42-V powernet using induction machine and direct torque control technique 总被引:3,自引:0,他引:3
Jain A.K. Mathapati S. Ranganathan V.T. Narayanan V. 《Power Electronics, IEEE Transactions on》2006,21(3):701-710
This paper describes an integrated starter generator (ISG) for automobile applications with 42-V powernet. This system is based on an induction machine which is directly mounted on the engine crankshaft and controlled using the technique of direct torque control (DTC). The suitability of the technique for ISG application is explained. The control structure of DTC for ISG application is described. Detailed experimental results from a 1.4-1 diesel engine are presented demonstrating the performance of the system during cranking as well as generation. The ISG also incorporates the feature of "on the fly start" during generation mode. Details of a low voltage high current power converter developed for this application are also given. 相似文献
67.
Halari Rozmin; Hines Melissa; Kumari Veena; Mehrotra Ravi; Wheeler Mike; Ng Virginia; Sharma Tonmoy 《Canadian Metallurgical Quarterly》2005,119(1):104
Sexually dimorphic cognitive performance in men (n=42) and women (n=42) was related to testosterone, estradiol, progesterone, luteinizing hormone, follicle-stimulating hormone, and sex hormone binding globulin, measured in 10-ml blood samples collected between 0900 and 1030 and, among women, during the follicular phase of the menstrual cycle. Significant sex differences favored men on spatial tasks (Mental Rotation and Judgment of Line Orientation) and on an inhibition task and favored women on a verbal task (category fluency). However, there were no significant relationships between any of the hormones and cognitive performance, suggesting that there are few, if any, consistent, substantial relationships between endogenous, nonfluctuating levels of gonadal hormones or gonadotropins and these cognitive abilities in men or women. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
68.
Magdy S. Abadir Kenneth L. Albin John Havlicek Narayanan Krishnamurthy Andrew K. Martin 《Formal Methods in System Design》2003,22(2):117-123
Formal tools are either too labor intensive or are completely impractical for industrial-size problems. This paper describes two formal verification tools used within Motorola, Versys2 and CBV, that challenge this assertion. The two tools are being used in current design verification flows and have shown that it is possible to seamlessly integrate formal tools into existing design flows. 相似文献
69.
This paper explores the suitability of the emerging passive star-coupled optical interconnection using wavelength division multiplexing as the system interconnect to provide high bandwidth (Gbits/sec) communication demanded by heterogeneous systems. Several different communication strategies (combinations of communication topologies and protocols) are investigated under a representative master-slave computational model. The interplay between system speed, network speed, task granularity, and degree of parallelism is studied using both analytical modeling and simulations. It is shown that a hierarchical ALOHA-based communication strategy between the master and the slaves, implemented on top of the passive star-coupled network, leads to a considerable reduction in channel contention and provides 50–80% reduction in task completion time for applications with medium to high degrees of coarse grain parallelism. Comparable reduction in channel contention is also shown to be achieved by using tunable acoustooptic filters at master nodes. 相似文献
70.
Kai Tang Ming-En Wang Lin-Lin Chen Shuo-Yan Chou Tony C. Woo Ravi Janardane 《Computer aided design》1997,29(12):825-836
A translational sweep is the translating of a polygon, called the generatrix G, around another polygon, called the directrix D, under two conditions: (1) G is always in contact with D; and (2) the interiors of G and D do not intersect. Three classes of translational sweep are studied, including the case in which both G and D are convex; the case in which G is convex, D monotone; and the case in which both are monotone. Efficient algorithms for computing the trajectory and the swept area as well as geometric and computational properties are presented for each class. A notion called the inverse generatrix, which reveals a duality between the trajectory and the swept polygon, is introduced to reduce complexity. 相似文献