In this article, we propose a new paradigm of control, called a maximum hands-off control. A hands-off control is defined as a control that has a much shorter support than the horizon length. The maximum hands-off control is the minimum support (or sparsest) control among all admissible controls. We first prove that a solution to an L1-optimal control problem gives a maximum hands-off control, and vice versa. This result rationalizes the use of L1 optimality in computing a maximum hands-off control. The solution has in general the “bang-off-bang” property, and hence the control may be discontinuous. We then propose an L1/L2-optimal control to obtain a continuous hands-off control. Examples are shown to illustrate the effectiveness of the proposed control method.

Purpose: The goal of this study was to assess the prevalence of speech and language disorders (SLD) in children with intellectual disability. Method: The sample comprised 167 children of both sexes, with mild and moderate intellectual disability of varied etiologies. Data on their language disorders were taken from the educational records in the school files. Results: It was demonstrated that the total prevalence of SLD in this sample was high (71.3%). While there were no statistical differences in the prevalence of SLD in relation to the sex of the child, there were significant differences in relation to the level and etiology of intellectual disability. Conclusion: Given the high prevalence of SLD, it is necessary to provide speech and language therapy to all children with intellectual disability who attend regular schools and special education centres. Speech therapy should begin as soon as they are admitted to preschool and school institutions. doi 10.5463/DCID.v24i1.214