Efficient data retrieval algorithms for multiple requests in MIMO wireless networks

2014 ◽  
Vol 30 (1) ◽  
pp. e2917 ◽  
Author(s):  
Ping He ◽  
Hong Shen ◽  
Longkun Guo ◽  
Yidong Li
2003 ◽  
pp. 252-281
Author(s):  
Leonardo Tininini

A powerful and easy-to-use querying environment is certainly one of the most important components in a multidimensional database, and its effectiveness is influenced by many other aspects, both logical (data model, integration, policy of view materialization, etc.) and physical (multidimensional or relational storage, indexes, etc.). As is evident, multidimensional querying is often based on the metaphor of the data cube and on the concepts of facts, measures, and dimensions. In contrast to conventional transactional environments, multidimensional querying is often an exploratory process, performed by navigating along the dimensions and measures, increasing/decreasing the level of detail and focusing on specific subparts of the cube that appear to be “promising” for the required information. In this chapter we focus on the main languages proposed in the literature to express multidimensional queries, particularly those based on: (i) an algebraic approach, (ii) a declarative paradigm (calculus), and (iii) visual constructs and syntax. We analyze the problem of evaluation, i.e., the issues related to the efficient data retrieval and calculation, possibly (often necessarily) using some pre-computed data, a problem known in the literature as the problem of rewriting a query using views. We also illustrate the use of particular index structures to speed up the query evaluation process.


2019 ◽  
pp. 138-157
Author(s):  
Maria Giovanna Mancini ◽  
Luigi Sauro

In this work, we present a detailed analysis of the different acceptations and practices of art criticism. This investigation underpins a novel conceptual modelling that extends Cidoc CRM and has been specifically designed to semantically annotate art criticism-related data and documents in order to enhance in this context interoperability and more efficient data retrieval.


2019 ◽  
Vol 2019 ◽  
pp. 1-8 ◽  
Author(s):  
Qinghua Liu ◽  
Fenfen Ke ◽  
Zhihua Liu ◽  
Jiaxin Zeng

With the rapid development of wireless networks, multiple network interfaces are gradually being designed into more and more mobile devices. When it comes to data delivery, Stream Control Transmission Protocol (SCTP)-based Concurrent Multipath Transfer (CMT) has proven to be quite useful solution for multiple home networks, and it could become the key transport protocol for the next generation of wireless communications. The CMT delay caused by data rearrangement has been noticed by researchers, but they have seldom considered the frequent occurrence of packet loss that occurs in the high-loss networks. In this paper, we proposed an original loss-aware solution for multipath concurrent transmission (CMT-LA) that achieves the following goals: (1) identifying packet loss on all paths, (2) distributing packets adaptively across multiple available paths according to their packet loss and loss variation, and (3) maintaining the features of bandwidth aggregation and parallel transmission of CMT while improving the throughput performance. The results of our simulations showed that the proposed CMT-LA reduces reordering delay and unnecessary fast retransmissions, thereby demonstrating that CMT-LA is a more efficient data delivery scheme than classic CMT.


Author(s):  
Vishnupriya V ◽  
Shameema Parveen A ◽  
Rithra R ◽  
Shanmugasundaram M ◽  
Manimegalai R

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