Flexible Query Systems for Relational Databases

Author(s):  
Rachid Mama ◽  
Mustapha Machkour ◽  
Mourad Ennaji ◽  
Karam Ahkouk
2011 ◽  
Vol 34 (2) ◽  
pp. 291-303 ◽  
Author(s):  
Li YAN ◽  
Zong-Min MA ◽  
Jian LIU ◽  
Fu ZHANG

1991 ◽  
Vol 24 (6) ◽  
pp. 315-322 ◽  
Author(s):  
S. P. Schreiner ◽  
M. Gaughan ◽  
H. L. Schultz ◽  
R. Walentowicz

The USEPA Office of Health and Environmental Assessment develops methodologies for conducting exposure and risk assessments. Protocols appropriate for specific analyses have been developed to aid in the selection of an exposure assessment model and to assess the validation and uncertainties associated with models used for toxic chemical exposure assessments in surface water, groundwater, and air. A software package has been developed to provide users with a quick and intuitive tool to access information for selected models and applications based on these protocols. The Integrated Model Evaluation System (IMES) is composed of three modules: 1) Selection, query systems for selecting a model based on technical criteria (currently for surface water, non-point source, and groundwater models); 2) Validation, a database containing validation and other information on over 50 models in various media; and 3) Uncertainty, a database demonstrating uncertainty simulations for several surface water models applied to exposure assessments of several chemicals. The selection modules are linked to the uncertainty and validation modules to access information for chosen models. The PC-based software system employs pull-down menus, help screens, and graphics to display its information.


Electronics ◽  
2021 ◽  
Vol 10 (15) ◽  
pp. 1778
Author(s):  
Binhao He ◽  
Meiting Xue ◽  
Shubiao Liu ◽  
Wei Luo

As one of the most important operations in relational databases, the join is data-intensive and time-consuming. Thus, offloading this operation using field-programmable gate arrays (FPGAs) has attracted much interest and has been broadly researched in recent years. However, the available SRAM-based join architectures are often resource-intensive, power-consuming, or low-throughput. Besides, a lower match rate does not lead to a shorter operation time. To address these issues, a Bloom filter (BF)-based parallel join architecture is presented in this paper. This architecture first leverages the BF to discard the tuples that are not in the join result and classifies the remaining tuples into different channels. Second, a binary search tree is used to reduce the number of comparisons. The proposed method was implemented on a Xilinx FPGA, and the experimental results show that under a match rate of 50%, our architecture achieved a high join throughput of 145.8 million tuples per second and a maximum acceleration factor of 2.3 compared to the existing SRAM-based join architectures.


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