Four Lessons in Versatility or How Query Languages Adapt to the Web

Exposing not only human-centered information, but machine-processable data on the Web is one of the commonalities of recent Web trends. It has enabled a new kind of applications and businesses where the data is used in ways not foreseen by the data providers. Yet this exposition has fractured the Web into islands of data, each in different Web formats: Some providers choose XML, others RDF, again others JSON or OWL, for their data, even in similar domains. This fracturing stifles innovation as application builders have to cope not only with one Web stack (e.g., XML technology) but with several ones, each of considerable complexity. With Xcerpt we have developed a rule- and pattern based query language that aims to give shield application builders from much of this complexity: In a single query language XML and RDF data can be accessed, processed, combined, and re-published. Though the need for combined access to XML and RDF data has been recognized in previous work (including the W3C’s GRDDL), our approach differs in four main aspects: (1) We provide a single language (rather than two separate or embedded languages), thus minimizing the conceptual overhead of dealing with disparate data formats. (2) Both the declarative (logic-based) and the operational semantics are unified in that they apply for querying XML and RDF in the same way. (3) We show that the resulting query language can be implemented reusing traditional database technology, if desirable. Nevertheless, we also give a unified evaluation approach based on interval labelings of graphs that is at least as fast as existing approaches for tree-shaped XML data, yet provides linear time and space querying also for many RDF graphs. We believe that Web query languages are the right tool for declarative data access in Web applications and that Xcerpt is a significant step towards a more convenient, yet highly efficient data access in a “Web of Data”

Erratum: "A Gravitational-wave Measurement of the Hubble Constant Following the Second Observing Run of Advanced LIGO and Virgo" (2021, ApJ, 909, 218)

[no abstract available

Insoluble residues of the Sauk sequence (Cambrian and lower Ordovician) rocks of the Fairfield basin, Illinois : an aid in correlation and in petroleum exploration

Includes bibliographical references (p. 12)

Forecast Study of Temperature of Shanghai Base on Energy Consuming Analysis

Based on the statistical data from National Bureau of Statistical ofChina, this paper shows the correlationship between the energy consumption ofthe provinces and temperature of corresponding capitals. After that Shanghai isresearched as an example, and an forecast of Shanghai’s temperature after 20years is draw out on condition that the energy consumption of this city keepsthe same increasing rate as the average value of the last 6 years up to 2008. Andthen it is shown that industry and traffic make up the main part of Shanghai’senergy consumption. Thus, it is educed as a conclusion that the futureachievement on the recycle of industrial residual heat and energy and on thecontrol of traffic energy consumption will be the effective approach to slow thetotal energy use increment and thus slow the temperature ascent