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Although additional studies are needed, our findings could provide information regarding the genetic aetiology of IDD in the Korean population.

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This study is intended to identify the applicability of energy harvesting technologies that are regarded as new electrical power sources for the sensors on high-speed trains. The analytic estimation research is conducted on the amount of electric energy harvested from the high-speed trains, operating at a maximum speed of over 400km/h to verify the applicability of the energy harvesting technology converting the vibration energy of axle and bogie into electric power. Based on the data of the vibration acceleration on the axles and bogies, which were measured by using a 500 Hz analog filter, an analytic estimation on the amount of power harvested by an electromagnetic resonant harvester is conducted through the analysis of the main frequency. The power of the electromagnetic resonant harvester is based on a theoretical model of the mass-spring-damper system, and the harvested power from the axles and bogies in the vertical direction is analytically estimated in this study. The analytic calculations typically give the target value for the final performance of the electromagnetic resonant energy harvester. The targets of the analytic estimations are given to provide the basis for the detailed design and to give a basis for defining the basic design parameters of the electromagnetic resonant energy harvester.Electronics 2020, 9, 403 2 of 16 prevent system failure and accidents [12][13][14]. The high-speed train mostly uses the wired sensors for the monitoring system [15]. Recently, the demand for a monitoring system using a wireless sensor is gradually increasing; however, there are limitations at present regarding the installation and the difficulty of accessing high-speed trains. In particular, when applied to the monitoring system of the high-speed train using wireless sensors and IT technology, maintenance based on real-time conditions during driving becomes possible, which differs from the methods currently used in maintenance management such as periodic disassembly and inspection. As a result, the reliability and stability of the train can be improved [16].However, even in the case of wireless sensors with less installation and location constraints, the power supply problem must be solved for the innovative monitoring system. As the current energy density increase rate of the battery does not meet the demands of the application, periodic battery replacement is necessary for real-time or long-term monitoring of the high-speed train. The battery replacement, which consumes energy continuously is a limited resource, is non-environmentally friendly, and generates additional maintenance tasks [17]. Therefore, the intelligent monitoring of high-speed trains requires the development of environmentally friendly and semi-permanent 'energy harvesting' powered monitoring technology through the use of exploiting the ambient energy generated during system operation.Energy harvesting module research using electromagnetic induction should analyze the characteristics of mechanical motion [18]. Mechanical motion characteristics...

An electromagnetic energy harvesting device was studied based on the design parameters of an energy harvesting device for the power source of wireless sensors node on the rolling stock. The characteristics of the generated power by the energy harvesting device were tested using the laboratory equipment and a rolling stock (a high-speed train). First, a cantilever beam energy harvesting device, which allows for easy adjustment of the length according to the frequency and the power according to the cantilever beam materials, was researched. In addition, the new design for a practical resonant energy harvesting device for the railroad system was performed. To realize the performance of the practical resonant energy harvesting device, the generated power characteristics of the energy harvesting device were tested according to the moving displacement, the number of coil turns, and the initial coil displacement between the coil and magnet. The evaluation of the performance of the manufactured resonant energy harvesting device for the railroad system, which the parameters were determined based on the test results, was conducted under real driving conditions in the high-speed train, which was traveling at 300 km/h. Finally, this study analyzed whether the power generated could be applied to the wireless sensor nodes for the railroad system.

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Durability is one of the critical issues concerning energy harvesting devices. Even with the energy harvesting device’s excellent performance design, the moving components, such as the spring, get damaged during operation. In this study, an energy harvesting device was designed for durability improvement. The mechanical stopper of the energy harvesting device was selected as a new design component to prevent spring damage. An experimental and finite element analysis (FEA) was carried out on the amount of energy harvesting power possible using a mechanical stopper to improve the durability of the energy harvesting device. A performance evaluation of the energy harvesting device using the mechanical stopper was conducted under laboratory and driving conditions of a high-speed train traveling at 300 km/h. The measurement of the generated power gives the target value for the minimum performance of the newly designed energy harvesting device used as the power source of the wireless sensor node for high-speed trains.

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