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Qianchu Liu's CV. Created with the Medium Length CV template

Technische Mechanik is a scientific journal for fundamentals and applications of engineering mechanics. Established in 1980 the Technische Mechanik is a periodical which publishes scientific papers from the entire field of mechanics ; i.e. all branches of theoretical and applied mechanics including related fields of study. The journal Technische Mechanik is an Open Access journal. All papers are available free of charge for download. Publishing of papers is free of any costs for the authors. Each submitted paper runs through a standard peer review process. Website: http://www.ovgu.de/techmech

The efficiency of a query execution plan depends on the accuracy of the selectivity estimates given to the query optimiser by the cost model. The cost model makes simplifying assumptions in order to produce said estimates in a timely manner. These assumptions lead to selectivity estimation errors that have dramatic effects on the quality of the resulting query execution plans. A convenient assumption that is ubiquitous among current cost models is to assume that attributes are independent with each other. However, it ignores potential correlations which can have a huge negative impact on the accuracy of the cost model. In this paper we attempt to relax the attribute value independence assumption without unreasonably deteriorating the accuracy of the cost model. We propose a novel approach based on a particular type of Bayesian networks called Chow-Liu trees to approximate the distribution of attribute values inside each relation of a database. Our results on the TPC-DS benchmark show that our method is an order of magnitude. more precise than other approaches whilst remaining reasonably efficient in terms of time and space.

Shape feature extraction for image recognition with CNN using frequency domain

A small effort for internships and jobs. Created based on the Medium Length CV template.

OIST PhD Thesis template

En este trabajo hablaremos de como estamos inmersos en un mundo que gira en gran medida en torno a Internet y a las redes sociales donde la identidad digital es casi tan importante como la real. Esto se acentúa aún más cuando nos referimos al sector más joven de la población, siendo considerados nativos digitales ya que son quienes más las usan y quienes tienen un mayor dominio de las mismas debido a que prácticamente han crecido junto a ellas. El presente trabajo de investigación pretende analizar el uso que los jóvenes hacen de las redes sociales. También se pretende resaltar las ventajas y los inconvenientes que éstas producen sobre todo a los más jóvenes y de qué manera el trabajo social se puede beneficiar de esta nueva e importante forma de socialización que ofrecen las nuevas tecnologías y en particular las redes sociales.

OIST PhD Thesis Proposal

A template in Swedish for a Bachelor Thesis at the Division of Statistics and Machine Learning at Linköping University.