• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.9
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• pp.4220-4241
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• 2017

For the downlink energy-harvesting small cell network, this paper proposes an interference management algorithm based on distributed coalitional game. The cooperative interference management problem of the energy-harvesting small cells is modeled as a coalitional game with transfer utility. Based on the energy harvesting strategy of the small cells, the time sharing mode of the small cells in the same coalition is determined, and an optimization model is constructed to maximize the total system rate of the energy-harvesting small cells. Using the distributed algorithm for coalition formation proposed in this paper, the stable coalition structure, optimal time sharing strategy and optimal power distribution are found to maximize the total utility of the small cell system. The performance of the proposed algorithm is discussed and analyzed finally, and it is proved that this algorithm can converge to a stable coalition structure with reasonable complexity. The simulations show that the total system rate of the proposed algorithm is superior to that of the non-cooperative algorithm in the case of dense deployment of small cells, and the proposed algorithm can converge quickly.

• Journal of Satellite, Information and Communications
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• v.10 no.2
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• pp.10-13
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• 2015

This paper proposed a novel user's information feedback algorithm for improving network energy harvesting rate. The proposed algorithm is focused on determining energy harvesting users comparing increasing ratio of the amount of harvesting energy versus emitted energy and network threshold ${\alpha}$, which is critical harvesting parameter. Using this method, we can increase the rate of network energy harvesting preventing emitted energy from wasting inefficiently. The result of experiment in this paper shows that user's information feedback algorithm makes network energy harvesting rate more efficiently when it uses threshold ${\alpha}=15%$ to determine energy harvesting users.

• Journal of information and communication convergence engineering
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• v.10 no.4
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• pp.359-364
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• 2012

Harvesting energy from the environment is essential for many applications to slow down the deterioration of energy of the devices in sensor networks and in general, the network itself. Energy from the environment is an inexhaustible supply which, if properly managed and harvested from the sources, can allow the system to last for a longer period - more than the expected lifetime at the time of deployment, or even last indefinitely. The goal of this study is to develop a simple algorithm for ns-2 to simulate energy harvesting in wireless sensor network simulations. The algorithm is implemented in the energy module of the simulator. Energy harvesting algorithms have not yet been developed for ns-2. This study will greatly contribute to the existing knowledge of simulating wireless sensor networks with energy harvesting capabilities in ns-2. This paper will also serve as a basis for future research papers that make use of energy harvesting.

• Journal of Satellite, Information and Communications
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• v.11 no.3
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• pp.6-11
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• 2016

In this paper, we studied a spectrum sensing algorithm for the efficient use of available spectrum in RF energy harvesting system combined with backscatter communication. We first looked for white spaces and then, selected low fading channel among white spaces using spectrum sensing algorithm at a transmitter. The transmitter employing the algorithm alleviates signal interference and improves the received signal strength indication through signals transmitted by low fading channel. The proposed RF energy harvesting system combined with backscatter communication is used the transmitter employing the algorithm. As a result of computer simulations, we can find the performance improvements of RF energy harvesting, BER of backscatter communication, and the received signal strength per distance of backscatter tag.

• Smart Structures and Systems
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• v.19 no.4
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• pp.403-413
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• 2017

The present article encompasses a nonlinear finite element (FE) and genetic algorithm (GA) based optimal vibration energy harvesting from nonprismatic piezo-laminated cantilever beams. Three cases of cross section profiles (such as linear, parabolic and cubic) are modelled to analyse the geometric nonlinear effects on the output responses such as displacement, voltage, and power. The simultaneous effects of taper ratios (such as breadth and height taper) on the output power are also studied. The FE based nonlinear dynamic equation of motion has been solved by an implicit integration method (i.e., Newmark method in conjunction with the Newton-Raphson method). Besides this, a real coded GA based constrained optimization scheme has also been proposed to determine the best set of design variables for optimal harvesting of power within the safe limits of beam stress and PZT breakdown voltage.

• ETRI Journal
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• v.33 no.6
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• pp.973-976
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• 2011

This letter describes an efficient technique for maximum power point tracking (MPPT) of an energy harvesting device. It is based on controlling the device voltage at the point of maximum power. Using a microcontroller with a power saving technique, the MPPT algorithm maintains the maximum power with low power consumption. An experiment shows that the algorithm maximizes the energy transfer power using an energy management IC fabricated in a 0.18-${\mu}m$ process. Compared to direct energy transfer to a battery, the proposed technique is more efficient for low-energy harvesting under variable conditions.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.8 no.10
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• pp.3321-3341
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• 2014

This paper investigates the outage performance and optimization for the four-phase two-way transmission network with an energy harvesting (EH) relay. To enable the simultaneous information processing and energy harvesting at the relay, we firstly propose a power splitting-based two-way relaying protocol (PSTWR). Then, we discuss its outage performance theoretically and derive an explicit expression for the system outage probability. In order to find the optimal system configuration parameters such as the optimal power splitting ratio and the optimal transmit power redistribution factor, we formulate an outage-minimized optimization problem. As the problem is difficult to solve, we design a genetic algorithm (GA) based algorithm for it. Besides, we also investigate the effects of the power splitting ratio, the power redistribution factor at the relay, and the source to relay distance on the system outage performance. Finally, extensive simulation results are provided to demonstrate the accuracy of the analytical results and the effectiveness of the GA-based algorithm. Moreover, it is also shown that, the relay position greatly affects the system performance, where relatively worse outage performance is achieved when the EH relay is placed in the middle of the two sources.

• Journal of Satellite, Information and Communications
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• v.10 no.2
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• pp.24-29
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• 2015

Recently, with developments of various networks, devices and various services, energy efficiency has become one of the most crucial issues with respect to sustainability of mobile devices. For connecting to networks seamlessly to offer services, a scenario of RF energy harvesting which supplies energy to wireless devices with RF signals is assumed. To increase the efficiency of RF energy harvesting, this paper proposes a RF energy harvesting algorithm which is based upon a frequency selective fading map. Through the algorithm, a receiver of mobile device can get fading information at each frequency and select a frequency which has the best quality. At the end, the simulation result demonstrates its superiority by showing a 4.45dB improvement in comparison to a deep fading frequency point.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.12
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• pp.98-106
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• 2013

The duty-cycle synchronization among mobile sensor nodes with energy-harvesting is very important. The nodes should keep their duty-cycle same to others as much as possible because they have to cooperate each other and to consume energy efficiently. The distribution of node position in network affects not only node connectivity but also the active time of synchronized nodes, and it relates to network life-time finally. In this paper, we introduce a network topology change algorithm (TCA) for energy-harvesting mobile sensor networks based on self-synchronized duty-cycling. The algorithm tries to change a network topology into a balanced topology where the mobile sensor nodes are unified according to the density of the number of nodes. For TCA, both fluid flow algorithm and flock dispersion algorithm are proposed and they are evaluated through the simulation in agent based modeling language. TCA is applied to the energy-harvesting mobile sensor networks to improve the synchronization of duty-cycle and to reduce the variation of energy consumption among nodes.

• Journal of Aerospace System Engineering
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• v.16 no.1
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• pp.49-55
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• 2022

The role of drones has been expanded to various fields such as agriculture, construction, and logistics. In particular, agriculture drones are emerging as an effective alternative to solve the problem of labor shortage and reduce the input cost. In this study therefore, we proposed the fruit recognition algorithm and harvesting mechanism for fruit harvesting drone system that can safely harvest fruits at high positions. In the fruit recognition algorithm, we employ "You-Only-Look-Once" which is a deep learning-based object detection algorithm and verify its feasibility by establishing a virtual simulation environment. In addition, we propose the fruit harvesting mechanism which can be operated by a single driving motor. The rotational motion of the motor is converted into a linear motion by the scotch yoke, and the opened gripper moves forward, grips a fruit and rotates it for harvesting. The feasibility of the proposed mechanism is verified by performing Multi-body dynamics analysis.