Semi-structured data has become prevalent with the growth of the Internet. The data is usually stored in a traditional database system or in a specialized repository. While many information providers have presented their databases on the web as semi-structured data, other information providers are developing repositories for new application. One such application is e-commerce, which is emerging...

We study the complexity of the inclusion, equivalence, and intersection problem for simple regular expressions arising in practical XML schemas. These basically consist of the concatenation of factors where each factor is a disjunction of strings possibly extended with ‘∗’ or ‘?’. We obtain lower and upper bounds for various fragments of simple regular expressions. Although we show that inclusi...

We study the problem of learning two regimes (we have a normal and a prefault regime in mind) based on a train set of non-Markovian observation sequences. Key to the model is that we assume that once the system switches from the normal to the prefault regime it cannot restore and will eventually result in a fault. We refer to the particular setting as semi-supervised since we assume the only in...

Choice functions on tournaments always select the maximal element (Condorcet winner), provided they exist, but this property does not hold in the more general case of weak tournaments. In this paper we analyze the relationship between the usual choice functions and the set of maximal elements in weak tournaments. We introduce choice functions selecting maximal elements, whenever they exist. Mor...

Semi-metals might offer a stronger interaction and a better confinement for terahertz wave than semiconductors, while preserve tunability. Particularly, graphene-based materials are envisioned as terahertz modulators, filters and ultra-broadband sources. However, the understanding of terahertz generation from those materials is still not clear, thus limits us recognizing the potential and impro...

Semi-supervised object detection algorithms based on the self-training paradigm produce pseudo bounding boxes with unavoidable noise. We propose a semi-supervised algorithm teacher-student models strong-weak heads to cope this problem. The strong and weak of teacher model solve quality measurement problem label localization obtain higher-quality labels. student are decoupled reduce negative imp...