There is a possibility of overlapping access data paths and shared computation among different queries in database systems, and batch processing of queries in workloads is called Multiple-Query-at-a-Time model. Several developed multi-query processing frameworks have been proven effective, but all of them lack a general framework for building complete query processing and optimization methods. On the basis of a query time operator merging optimization framework constructed based on equivalent transformation, a relational operator concurrent computing framework for heterogeneous architectures, called OmegaDB, was proposed. In this framework, by studying the GPU-oriented relational operator flow-batch computing model, and constructing the relational data query pipeline, a flow-batch computing method aggregating multiple-query was implemented on the CPU-GPU heterogeneous architecture. On experiments and prototype implementation, the advantages of OmegaDB were verified through theoretical analysis and experimental results by comparing with Relational Database Management System (RDBMS), and the potential of OmegaDB in utilizing new hardware was shown. According to the theoretical study of query optimization frameworks of Multiple-Query-at-a-Time models based on the traditional relational algebraic rules, several optimization methods were proposed and future research directions were prospected. Using TPC-H business intelligence computing as a benchmarking program, the results show that OmegaDB achieves up to 24 times end-to-end speedup while consuming lower disk I/O and CPU time than the modern advanced commercial database system SQL SERVER.
Because of the literature search system failing to comprehend users' real-time demands, a method to find users' real-time demands for literature search systems was proposed. Firstly, this method analyzed the users' personalized search behaviors such as browsing and downloading. Secondly, it established users' real-time Requirement Documents (RD) based on the relations between users' search behaviors and users' requirements. And then it extracted keyword network from requirement documents. Finally, it gained users' demand graphs which were formed by core nodes extracted from keyword network by means of random walk. The experimental results show that the method by extracting demand graphs increases the F-measure by 2.5%, in the comparison of the K-medoids algorithm on average, under the condition that users' demands are emulated in the experiment. And it also increases the F-measure by 5.3%, in the comparison with the DBSCAN (Density-Based Spatial Clustering of Applications with Noise) algorithm on average, under the condition that users really searches for papers. So, when the method is used in literature search systems where users' requirements are stable, it will be able to gain users' demands to enhance users' search experiences.