Sensitivity volume as figure-of-merit for maximizing data importance in electrical impedance tomography.

Objective.Electrical impedance tomography (EIT) is a noninvasive imaging method whereby electrical measurements on the periphery of a heterogeneous conductor are inverted to map its internal conductivity. The EIT method proposed here aims to improve computational speed and noise tolerance by introducing sensitivity volume as a figure-of-merit for comparing EIT measurement protocols.Approach.Each measurement is shown to correspond to a sensitivity vector in model space, such that the set of measurements, in turn, corresponds to a set of vectors that subtend a sensitivity volume in model space. A maximal sensitivity volume identifies the measurement protocol with the greatest sensitivity and greatest mutual orthogonality. A distinguishability criterion is generalized to quantify the increased noise tolerance of high sensitivity measurements.Main result.The sensitivity volume method allows the model space dimension to be minimized to match that of the data space, and the data importance to be increased within an expanded space of measurements defined by an increased number of contacts.Significance.The reduction in model space dimension is shown to increasecomputational efficiency, accelerating tomographic inversion by several orders of magnitude, while the enhanced sensitivitytolerates higher noiselevels up to several orders of magnitude larger than standard methods.

Establishing Foundational Nonarbitrary Distinctive and Categorical Relational Responding in Children with Autism.

The present study sought to evaluate a sequence of training procedures on the emergence of foundational relational responses that underly more complex distinctive (i.e., difference) and hierarchical (i.e., categorical) relational frames. In a multiple baseline design, an initial baseline period with three children with autism showed that the participants did not select nonidentical stimuli from an array when presented the contextual cue "different." Simple discrimination training was efficacious in establishing this response and the skill transferred to a novel set of stimuli without reinforcement. In a second baseline period, participants did not demonstrate conditional identical/nonidentical relational responses when provided the contextual cues "same" and "different." Conditional discrimination training with all three participants was again efficacious in establishing the conditional reflexive and distinctive responses and the skill transferred to untrained stimuli. In a third baseline period, participants did not demonstrate correct conditional categorization/sorting. Like in the prior two training conditions, training was efficacious in establishing the target response with a generalized transfer to untrained stimuli.