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The electro-hydraulic servo system (EHSS) usually demonstrates a lower efficiency in comparison to other available actuation methods. Thus, an energy-saving control strategy based on a load-sensing structure is developed in this study to improve the system efficiency of EHSS. The presented controller employs variable supply pressure control (VSPC) to reduce the pressure loss across the valve. Unlike the existing VSPC, a load-sensing structure that consists of a load-sensing pump, a proportional relief valve (PRV), and a throttle valve is proposed. Therefore, the overflow loss can also be decreased. Additionally, an adaptive backstepping sliding mode control is presented for the purpose of position tracking. Compared with the fixed displacement system, the proposed method is capable of saving 62.5 % and 90 % energy for the harmonic reference tests and multi-step reference tests, respectively, during the task of position tracking.

Four fifth-grade classrooms embarked on a modified ubiquitous computing initiative in the fall of 2003. Two 15-computer wireless laptop carts were shared among the four classrooms in an effort to integrate technology across the curriculum and affect change in student learning and teacher pedagogy. This initiative-in contrast to other one-to-one programmemess and stationary labs-offers public schools alternatives to budget constraints and instructional-space overhead. Results indicate positive teacher technology competence and confidence, as well as instructional strategies that were student-centred made meaningful uses of technology. Teacher technological knowledge and efficacy, pedagogical knowledge, and a supportive school community seem to be strong indicators for impacting technology integration in this context.