Better answers to real questions

Abstract

The lack of access to visual information like text labels, icons, and colors can cause frustration and decrease independence for blind people. Current access technology uses automatic approaches to address some problems in this space, but the technology is error-prone, limited in scope, and quite expensive. In this paper, we introduce VizWiz, a talking application for mobile phones that offers a new alternative to answering visual questions in nearly real-time-asking multiple people on the web. To support answering questions quickly, we introduce a general approach for intelligently recruiting human workers in advance called quikTurkit so that workers are available when new questions arrive. A field deployment with 11 blind participants illustrates that blind people can effectively use VizWiz to cheaply answer questions in their everyday lives, highlighting issues that automatic approaches will need to address to be useful. Finally, we illustrate the potential of using VizWiz as part of the participatory design of advanced tools by using it to build and evaluate VizWiz::LocateIt, an interactive mobile tool that helps blind people solve general visual search problems.

Thirty Years of Virtual Substitution

“…Virtual substitution was implemented by Weispfenning's students in the computer logic system Redlog [20,23,55,56], which developed into an established tool with about 400 citations in the scientific literature pointing at quite a number of successful applications, mostly in the sciences. Such implementations require powerful heuristics, which by themselves establish significant research in symbolic computation [17,18,21,25,33,35,51,[58][59][60]. As the above-mentioned complexity results suggest, the focus is on problems with few quantifier alternations and with parameters.…”

“…Another aspect are heuristics for degree reductions. Those are equivalence transformations heuristically working against the increase of degrees with non-linear real virtual substitution, specifically polynomial factorization and degree shifts [25,34,35].…”

A Survey of Some Methods for Real Quantifier Elimination, Decision, and Satisfiability and Their Applications

“…All examples discussed in this article have been computed with an implementation of VS in Redlog that is limited to formulas where for the elimination of a quantifier the total degree of the corresponding quantified variable does not exceed 2. Nevertheless we will encounter significantly higher degrees, because VS implementations are supplemented with powerful simplification strategies; see, e.g., [20] and [36,Section 5]. The nonlinear bound of 2 is based on work by Weispfenning in the early 1990s, which also theoretically discussed arbitrary degree bounds [73].…”

“…For fixed choices of parameters, non-standard elements can be efficiently eliminated from the sample solutions in a post-processing step [36]. Finally, with universal quantifiers we have the following dual semantics: For fixed choices of all parameters, whenever some left hand side condition does not hold, then ∀x 1 ψ does not hold, and the corresponding right hand side assignment is one counterexample.…”

Adapting Real Quantifier Elimination Methods for Conflict Set Computation

“…However, a critical feature is that the complete engine provides models, both for feedback to the user but also for model-based combination with other theories [12,13]. Adapting established real closed field decision procedures to produce models has been the subject of a previous work [21]. The other critical feature is to be able, from an unsatisfiable set of constraints, to extract a small conflict set.…”