Sparse and Constrained Stochastic Predictive Control for Networked Systems

This article presents a novel class of control policies for networked control of Lyapunov-stable linear systems with bounded inputs. The control channel is assumed to have i.i.d. Bernoulli packet dropouts and the system is assumed to be affected by additive stochastic noise. Our proposed class of policies is affine in the past dropouts and saturated values of the past disturbances. We further consider a regularization term in a quadratic performance index to promote sparsity in control. We demonstrate how to augment the underlying optimization problem with a constant negative drift constraint to ensure mean-square boundedness of the closed-loop states, yielding a convex quadratic program to be solved periodically online. The states of the closed-loop plant under the receding horizon implementation of the proposed class of policies are mean square bounded for any positive bound on the control and any non-zero probability of successful transmission

Development and validation of a computerized expert system for evaluation of automated visual fields from the Ischemic Optic Neuropathy Decompression Trial

BACKGROUND: The objective of this report is to describe the methods used to develop and validate a computerized system to analyze Humphrey visual fields obtained from patients with non-arteritic anterior ischemic optic neuropathy (NAION) and enrolled in the Ischemic Optic Neuropathy Decompression Trial (IONDT). The IONDT was a multicenter study that included randomized and non-randomized patients with newly diagnosed NAION in the study eye. At baseline, randomized eyes had visual acuity of 20/64 or worse and non-randomized eyes had visual acuity of better than 20/64 or were associated with patients refusing randomization. Visual fields were measured before treatment using the Humphrey Field Analyzer with the 24-2 program, foveal threshold, and size III stimulus. METHODS: We used visual fields from 189 non-IONDT eyes with NAION to develop the computerized classification system. Six neuro-ophthalmologists ("expert panel") described definitions for visual field patterns defects using 19 visual fields representing a range of pattern defect types. The expert panel then used 120 visual fields, classified using these definitions, to refine the rules, generating revised definitions for 13 visual field pattern defects and 3 levels of severity. These definitions were incorporated into a rule-based computerized classification system run on Excel(® )software. The computerized classification system was used to categorize visual field defects for an additional 95 NAION visual fields, and the expert panel was asked to independently classify the new fields and subsequently whether they agreed with the computer classification. To account for test variability over time, we derived an adjustment factor from the pooled short term fluctuation. We examined change in defects with and without adjustment in visual fields of study participants who demonstrated a visual acuity decrease within 30 days of NAION onset (progressive NAION). RESULTS: Despite an agreed upon set of rules, there was not good agreement among the expert panel when their independent visual classifications were compared. A majority did concur with the computer classification for 91 of 95 visual fields. Remaining classification discrepancies could not be resolved without modifying existing definitions. Without using the adjustment factor, visual fields of 63.6% (14/22) patients with progressive NAION and no central defect, and all (7/7) patients with a paracentral defect, worsened within 30 days of NAION onset. After applying the adjustment factor, the visual fields of the same patients with no initial central defect and 5/7 of the patients with a paracentral defect were seen to worsen. CONCLUSION: The IONDT developed a rule-based computerized system that consistently defines pattern and severity of visual fields of NAION patients for use in a research setting

Ischemic Optic Neuropathy Decompression Trial: An Update

As recently as 1989 ophthalmologists had no treatment for non-arteritic anterior ischemic optic neuropathy (NAION). Primarily affecting the elderly, NAION can devastate vision since it affects both eyes in 40% of afilicted patients and leads to visual acuity of 20/200 or worse in 45% of affected eyes.1 Although most neuro-ophthalmologists believe that the likelihood of spontaneous improvement is low, published reports show a wide range of spontaneous visual improvement in cases of NAION, varying between 5% and 33%. Unfortunately, most published reports describing the natural history of NAION are based on medical records reviews and did not use standardized methods of data measurement or collection. In addition, most reports are based on small numbers of patients who were followed up for varying lengths of time. Until prospectively collected data on untreated patients become available, information regarding the natural history ofNAION must be interpreted cautiously

Comparing EPI-743 treatment in siblings with Leber's Hereditary Optic Neuropathy mt14484 mutation

Univ So Calif, Keck Sch Med, Dept Ophthalmol, Doheny Eye Inst, Los Angeles, CA 90033 USAUniversidade Federal de São Paulo, São Paulo, BrazilEdison Pharmaceut, Mountain View, CA USAMaryland Neuroophthalmol, Pikesville, MD USAUniversidade Federal de São Paulo, EPM, São Paulo, BrazilWeb of Scienc

Environmental Morale and Motivation

This chapter discusses the role of environmental morale and environmental motivation in individual behavior from the point of view of economics and psychology. It deals with the fundamental public good problem, and presents empirical (laboratory and field) evidence on how the cooperation problem can be overcome. Four different theoretical approaches are distinguished according to how individuals’ underlying environmental motivation is modeled. Specifically, we look at the interaction between environmental policy and environmental morale through the lens of cognitive evaluation theory (also known as crowding theory)