Context:Impairment of initiating sequential movements and processing of proprioception contribute to characteristic Parkinson's disease (PD) gait abnormalities. Many studies have used a single external cue or 2 different cues to correct PD gait.Aim:An aim of this study was to determine the influence of paired proprioceptive cues on gait parameters of individuals with PD.Setting and Design:Double-blind randomized controlled trial.Materials and Methods:Subjects were 30 PD patients who had mild to moderate impairment according to the United Parkinson's Disease Rating Scale (UPDRS). They were randomly assigned to either a routine physiotherapy program or treadmill training with vibratory stimuli applied to the feet plantar surfaces and proprioceptive neuromuscular facilitation (PNF) as well as the same physiotherapy program. All Participants received a 45-minutes session of low intensity physiotherapy program, 3 times a week, for 8 weeks. The duration of treadmill training was 5 minutes at baseline and 25 minutes at the end of treatment. Walking speed and distance were recorded from the treadmill control panel for both groups before and immediately after the end of treatment. The Qualysis ProReflex motion analysis system was used to measure cadence, stride length, hip, knee, and ankle joints’ angular excursion.Results:The cadence, stride length, and lower limb joints’ angular excursion showed a significant improvement in both groups (P ≤ 0.05). These improvements in spatio-temporal parameters and angular excursion were higher in the study group than in the control group (P ≤ 0.05).Conclusion:Potentiated proprioceptive feedback improves parkinsonian gait kinematics, the hip, knee, and ankle joints’ angular excursion.
In this paper, two control strategies are presented for the study of the control of a large-scale electric power system. In the first, the control is obtained by decomposition of the system to what are called I e-ccupled ' subsystems, and in the second, e. control strategy using closed-loop hierarchical control techniques is introduced. Finally, these two approaches are applied to a system consisting of three plants.
IntroductionThe electric power system is a complex one consisting of a large number of units of energy production interconnected by the network of transmission and distribution; the complexity of this system is increasing every day due to the exponential rise in its demand and increased dependence on its reliability and security. Due to economical and technical reasons, interconnections become vital to electric power systems, these interconnections increase the degree of complexity of the system-operating problem. Hence the problem of the control of a large-scale system will be an important one. The system is usually subjected to perturbations and it is necessary to bring it back to a steady state in an optimal or suboptimal manner; this is the role of the system regulators which include speed and voltage regulators. But the numerical calculation of the exact optimal control is impracticable for a large-scale power system. The purpose of this paper is to show two methods allowing a large-scale design problem to be split into a set of simpler subsystem problems. Recently, the problem of decomposition of a large-scale system has received the attention of many authors (Kokotovic et al. (1969) developed a method for computing near-optimal regulators for a linear system with quadratic performance indices. The first part of this paper is a generalization of this method as applied to a power system. Singh et al. (1976) and developed a method for providing the optimal feedback gain matrix for high-order linear quadratic problems using multi-level computation techniques. In the second part of this paper this method is applied to the electric power system.
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