• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.25 no.5
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• pp.362-367
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• 2016

Recently, wireless charging systems have expanded their applications from household electrical appliances to outdoor activity devices. In wireless charging systems, solar cells have versatile advantages, such as abundant raw materials within the earth, reasonable prices of products, and highest power conversion efficiency. In this study, the photovoltaic effect between a silicon solar cell and a photon of infrared wavelength was simulated using a Shockley diode equation. A solar cell power charging system was then set up to: 1) clarify mechanisms of the charging interaction based on the photovoltaic effect with a laser source, and 2) verify interdependency of the parameters: laser settings and geometrical position between a solar cell and the laser. As was observed, the solar cell generates more power when the photon was irradiated uniformly, intensively, and vertically on the surface of the solar cell.

• Journal of international Conference on Electrical Machines and Systems
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• v.1 no.2
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• pp.111-115
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• 2012

In this paper, a solar energy powered bicycle linked to a wireless sensor network (WSN) which monitors the transfer of solar energy to an electrical energy storage unit and an analysis of its effectiveness is proposed. In order to achieve this goal, a solar-powered bicycle with an attached ZigBee and a far-end wireless network supervisory system is setup. Experimental results prove that our prototype, solar energy powered bicycle, can achieve enough solar energy for charging a two lead-acid battery pack. As a result, the user, through use of a wireless network in the parking period can be kept aware of the data on the amount of immediate solar radiation, the degree of illumination, the ambient temperature, and electrical energy storage capacity information of the bicycle through an internet interface.

• The Journal of the Korea institute of electronic communication sciences
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• v.16 no.4
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• pp.605-610
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• 2021

Wireless charging method using a laser is considered as the most efficient method at a long distance of the wireless charging method. Combining long-range laser wireless charging technology with wireless communication technology will make it possible to use it for a variety of applications. Accordingly, this paper shows the results of research and experiments on wireless charging and wireless communication simultaneously based on a laser. This technique uses a laser as a light source for E/O(: Electric-to-Optical) conversion at the transmitter for optical wireless power transmission. In the experimental results, the optical power transmission using a 100 mW laser transmitter and a solar cells receiver showed a DC-to-DC efficiency of 1.9 %, wireless optical communication showed a transmission speed of up to 90 kbps when the transmission distance is 15 m.

• Journal of Korea Society of Industrial Information Systems
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• v.16 no.1
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• pp.31-36
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• 2011

Ubiquitous network and wireless sensor networks is being applied in various fields. Located at target areas, node of wireless sensor network uses batteries as a power source. Batteries have a limited energy in sensor network applications. Also, before use, the battery must be charged and It is difficult to replace the battery. Therefore, energy harvesting technology is being researched and being developed for long life of sensor node. Especially, sola energy is being extensively researched. because that can have great amounts of energy than other environmental energy in a short time. In this study, we tested battery charging and recharging, operation of sensor node using Solar Cell. Also, monitoring data gathering and voltage Analysis showed energy harvesting time of Sola Cell battery for sensor node and operation of sensor node.

• Journal of Sensor Science and Technology
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• v.21 no.5
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• pp.379-384
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• 2012

This paper presents the power source of wireless sensor node (WSN) using supercapacitors and a solar cell. Supercapacitors have high lifetime cycling compared to that of batteries. Supercapacitors are connected in series to achieve higher voltage and a voltage balancing circuit is required to ensure that no individual cell goes overvoltage. We employ an active balancing circuit that draws minimal current by using transistors. A diode is connected in series with each supercapacitor. A new balancing circuit that equalize the cells-voltage reduces energy consumption of supercapacitors. Voltage of operating WSN is applied 2.2-3.3V by DC/DC converter and supercapacitor voltage 2.2-5.1V. Maximum operating time of wireless sensor node is about 16 hours in full charging.

• IEMEK Journal of Embedded Systems and Applications
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• v.11 no.6
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• pp.379-392
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• 2016

This paper presents the design and simulation of a laser power beaming (LPB) system for an electric vehicle that establishes an optimal power transmission path based on the received signal strength. The LPB system is possible to transfer power from multiple transmitters to a single receiver according to the characteristics of the laser and the solar panel. When the laser beams of multiple transmitters aim at a solar panel at the same time, the received power is the sum of all energy at a solar panel. Our proposed LPB system consists of multiple transmitters and multiple receivers. The transmitter sends its power characteristics as optically coded pulses with a class 1 laser beam and powers as a high-intensity laser beam. By using the attenuated power level, the receiver can estimate the maximum receivable powers from the transmitters and select optimal transmitters. Throughout the simulation, we verified the possibility that different LPB receivers were achieved their required power by the optimal allocation of the transmitter among the various transmitters.

• Journal of the Korea Society of Computer and Information
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• v.25 no.2
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• pp.105-111
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• 2020

In this paper, we propose a scheme that minimizes the energy imbalance problem of solar-powered wireless sensor network (SP-WSN) using both a mobile sink capable of wireless power transfer and an efficient clustering scheme (including cluster head election). The proposed scheme charges the cluster head using wireless power transfer from a mobile sink and mitigates the energy hotspot of the nodes nearby the head. SP-WSNs can continuously harvest energy, alleviating the energy constraints of battery-based WSN. However, if a fixed sink is used, the energy imbalance problem, which is energy consumption rate of nodes located near the sink is relatively increased, cannot be solved. Thus, recent research approaches the energy imbalance problem by using a mobile sink in SP-WSN. Meanwhile, with the development of wireless power transmission technology, a mobile sink may play a role of energy charging through wireless power transmission as well as data gathering in a WSN. Simulation results demonstrate that increase the amount of collected data by the sink using the proposed scheme.

• Journal of KIISE
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• v.42 no.12
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• pp.1495-1502
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• 2015

Data compression involves a trade-off between delay time and data size. Greater delay times require smaller data sizes and vice versa. There have been many studies performed in the field of wireless sensor networks on increasing network life cycle durations by reducing data size to minimize energy consumption; however, reductions in data size result in increases of delay time due to the added processing time required for data compression. Meanwhile, as energy generation occurs periodically in solar energy-based wireless sensor networks, redundant energy is often generated in amounts sufficient to run a node. In this study, this excess energy is used to reduce the delay time between nodes in a sensor network consisting of solar energy-based nodes. The energy threshold value is determined by a formula based on the residual energy and charging speed. Nodes with residual energy below the threshold transfer data compressed to reduce energy consumption, and nodes with residual energy above the threshold transfer data without compression to reduce the delay time between nodes. Simulation based performance verifications show that the technique proposed in this study exhibits optimal performance in terms of both energy and delay time compared with traditional methods.

• International Journal of Internet, Broadcasting and Communication
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• v.16 no.4
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• pp.168-173
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• 2024

This paper proposes a solution for innovating crime prevention and real-time response through the development of the Smart Drone Police System. The system integrates big data, artificial intelligence (AI), the Internet of Things (IoT), and autonomous drone driving technologies [2][5]. It stores and analyzes crime statistics from the Statistics Office and the Public Prosecutor's Office, as well as real-time data collected by drones, including location, video, and audio, in a cloud-based database [6][7]. By predicting high-risk areas and peak times for crimes, drones autonomously patrol these identified zones using a self-driving algorithm [5][8]. Equipped with video and voice recognition technologies, the drones detect dangerous situations in real-time and recognize threats using deep learning-based analysis, sending immediate alerts to the police control center [3][9]. When necessary, drones form an ad-hoc network to coordinate efforts in tracking suspects and blocking escape routes, providing crucial support for police dispatch and arrest operations [2][11]. To ensure sustained operation, solar and wireless charging technologies were introduced, enabling prolonged patrols that reduce operational costs while maintaining continuous surveillance and crime prevention [8][10]. Research confirms that the Smart Drone Police System is significantly more cost-effective than CCTV or patrol car-based systems, showing a 40% improvement in real-time response speed and a 25% increase in crime prevention effectiveness over traditional CCTV setups [1][2][14]. This system addresses police staffing shortages and contributes to building safer urban environments by enhancing response times and crime prevention capabilities [4].

• Journal of Advanced Marine Engineering and Technology
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• v.31 no.5
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• pp.583-591
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• 2007

This paper reports the performance of a 150W PV-wave hybrid system with battery storage in buoy. This system was originally designed to meet a new hybrid ower system for buoy in Korea. In the case or lighted buoys and lighthouses, a light failure alarm system of wireless radio is attached so that light failures are immediately notified to the office. At lighthouse offshore fixed lights and light buoys where commercial electricity is not available, the power source depends on solar system and batteries. This power system has a various problems. Therefore energy derived from the sunshine, wind and waves has been used as the energy source lot aids to navigation. Recently a hybrid system of combining the solar, wind and the wave generator is a favorable system lot the ocean facilities like lighthouse and buoy. The hybrid system in this paper is intended for variable DC load like light, communication system in the buoy and includes a PV-wane generation system and battery. This is composed a high efficiency charging algorithm, switching converter and controller. This paper includes discussion on system reliability, power quality, and effects of hybrid system in the buoy. Simulation and experimental results show excellent performance.