I give an account of the definitions of parton densities, both the conventional ones, integrated over parton transverse momentum, and unintegrated transverse-momentum-dependent densities. The aim is to get a precise and correct definition of a parton density as the target expectation value of a suitable quantum mechanical operator, so that a clear connection to non-perturbative QCD is provided....

I give an account of the definitions of parton densities, both the conventional ones, integrated over parton transverse momentum, and unintegrated transverse-momentum-dependent densities. The aim is to get a precise and correct definition of a parton density as the target expectation value of a suitable quantum mechanical operator, so that a clear connection to non-perturbative QCD is provided....

Recent discoveries in automated planning are broadening the scope of planners, from toy problems to real applications. However, applying automated planners to real-world problems is far from simple. On the one hand, the definition of accurate action models for planning is still a bottleneck. On the other hand, off-the-shelf planners fail to scale up and to provide good solutions in many domains...

As computers become more powerful and prevalent, more researchers are exploring computer tools to help novices gain an understanding into new work domains. The development of such tools involves what has been termed a “learner-centered design” process. But while there is an intuitive notion of what is meant by learner-centered design, there is no formal definition. Here we present our definitio...

We propose a method for acquiring plain lexical paraphrase using a Japanese dictionary in order to achieve lexical simplification for children. The proposed method extracts plain words that are the most similar to the headword from the dictionary definition. The definition statements describe the headword using plain words; therefore, paraphrasing by replacing the headword with the most similar...

The TREC 2004 Question Answering track contained a single task in which question series were used to define a set of targets. Each series contained factoid and list questions and related to a single target. The final question in the series was an “Other” question that asked for additional information about the target that was not covered by previous questions in the series. Each question type w...