Speech activity detection (or endpointing) is an important processing step for applications such as speech recognition, language identification and speaker diarization.Both audio-and vision-based approaches have been used for this task in various settings, often tailored toward end applications.However, much of the prior work reports results in synthetic settings, on taskspecific datasets, or on datasets that are not openly available.This makes it difficult to compare approaches and understand their strengths and weaknesses.In this paper, we describe a new dataset which we will release publicly containing densely labeled speech activity in YouTube videos 1 , with the goal of creating a shared, available dataset for this task.The labels in the dataset annotate three different speech activity conditions: clean speech, speech co-occurring with music, and speech cooccurring with noise, which enable analysis of model performance in more challenging conditions based on the presence of overlapping noise.We report benchmark performance numbers on AVA-Speech using off-the-shelf, state-of-the-art audio and vision models that serve as a baseline to facilitate future research.

With the advent of Web 2.0 technologies, websites have evolved from static pages to dynamic, interactive Web-based applications with the ability to replicate common desktop functionality. However, for blind and visually impaired individuals who rely upon screen readers, Web 2.0 applications force them to adapt to an inaccessible use model. Many technologies, including WAI-ARIA, AJAX, and improved screen reader support, are rapidly evolving to improve this situation. However, simply combining them does not solve the problems of screen reader users. The main contributions of this paper are two models of interaction for screen reader users, for both traditional websites and Web 2.0 applications. Further contributions are a discussion of accessibility difficulties screen reader users encounter when interacting with Web 2.0 applications, a user workflow design model for improving Web 2.0 accessibility, and a set of design requirements for developers to ease the user's burden and increase accessibility. These models, accessibility difficulties, and design implications are based directly on responses and lessons learned from usability research focusing on Web 2.0 usage and screen reader users. Without the conscious effort of Web engineers and designers, most blind and visually impaired users will shy away from using new Web 2.0 technology in favor of desktop based applications.

File systems coordinate simultaneous access of files by concurrent client processes. Although several processes may read a file simultaneously, the file system must grant exclusive access to one process wanting to write the file. Most file systems consider processes to be antagonistic: they prevent one process from taking actions on a file that have any chance to harm to another process already using the file. If several processes need to cooperate in a more sophisticated manner in their use of a file, they must communicate explicitly among themselves.