We propose a time slot based transmission strategy, referred to as adaptive coordinated napping (CoNap), for energy saving in cellular networks under time-varying traffic demand. In adaptive CoNap network, multiple neighboring base stations (BSs) form a cluster and each BS operates in either a transmit mode (TM) or a nap mode (NM) in each time slot. The dynamic assignment of TM and NM to each BS is implicitly coordinated among multiple BSs. This implicit coordination is realized by a binary general flickering pattern matrix (FPM) through adaptively selected mapping matrix (MM). To track the time-varying traffic demand, we develop an adaptive algorithm to dynamically select the appropriate MM from a predefined MM set by taking into account the network quality of service (QoS) requirement. Our numerical results based on a realistic energy consumption model in a cellular network show that as high as 40% saving can be achieved without compromising the network QoS.

In this paper, we will first motivate the heterogeneous network as an evolutionary path to the fifth generation (5G) communications. We then present an agile software defined heterogeneous network architecture which virtualizes the various radio access networks such as cellular basestations and Wi-Fi access points and the various carrier frequencies from both licensed and unlicensed bands. The software defined heterogeneous network architecture can therefore support much more efficient resource utilization and meet the quality of service requirement. We will also share our work in context-aware Wi-Fi-cellular network traffic steering and mobility management as two use cases in the software defined heterogeneous network.

Wheel loader shovel loading operation tests showed that when the tire slips, it not only causes waste of the engine power, but also increases the tire wear. In this paper, the regression prediction model is combined with the electro-hydraulic proportional control technology. For the first time, the method of adjusting the posture of the working device is proposed to realize the skid-proof shovel control strategy of the wheel loader. In this control strategy: (1) The electro-hydraulic proportional control technology applied to this wheel loader is introduced. (2) The load spectrum of the wheel loader is analyzed during the shovel loading operation. Moreover, combined with the drive shaft torque, pilot pressure and boom cylinder displacement, the particle swarm optimization-support vector machine (PSO-SVM) algorithm is used to complete the construction of the regression prediction model of the boom cylinder displacement. (3) A controller is designed based on the fractional-order PID control algorithm. The skid-proof control strategy is simulated and verified by constructing the joint simulation model. The corresponding program is prepared in the hydraulic system controller and the effectiveness of the control strategy and algorithm are verified by the wheel loader shovel loading operation.

Magnetostrictive materials with good mechanical properties can effectively convert the alternating magnetic energy in the environment into mechanical vibrations via the magnetostriction effect. Few studies exist on the working mechanism and the effect on the performance of magnetoelectric (ME) composite components in complex magnetic field environments. This work first investigated the magnetoelectric conversion process of two types of ME composite components under the action of DC magnetic field alone and the DC–AC coupled magnetic field using COMSOL simulation. When coupled with AC magnetic field, the DC bias magnetic field can enhance the magnetization by AC field for the Galfenol alloy component and negate the magnetization for the nickel component. Then, two types of ME composite components made from Galfenol alloy and nickel bonded with piezoelectric transducer are prototyped and tested for energy harvesting. The experimental results show that, under a harmonic excitation of 3 Oe magnetic field, the DC bias magnetic field of 120 Oe can increase the open-circuit voltage of the Galfenol alloy based harvester from 0.495 V to 10.68 V, and the output power from 1.6 μ W to 42 μ W by 2525% with a matched external resistance of 50 kΩ. Under the same amplitude of AC magnetic field, the DC bias magnetic field increases the open-circuit voltage of the nickel based harvester from 0.117 V to 0.837 V, and the output power from 2.6 μ W to 23 μ W by 784.6% with a matched resistance of 1000 kΩ. The findings of this work reveal the effect of the coupled magnetic field for the magnetostriction for different magnetostrictive materials and provide the guideline for the design of magnet electric energy harvesters.