• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.4
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• pp.648-655
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• 2019

This paper proposes the differential development of a Taekwondo electronic body protector. For this development, the most suitable sensor system was selected after analyzing and testing various sensor methods (magnetic sensors, electric capacity sensors, contact switch sensors, and piezo-film sensors) that could be applied in the electronic body protector, the selected sensors were distributed to the body and feet to make a more precise hit score, unlike the existing system in which all sensors are centralized on the body. Furthermore, it aims to illuminate using a lightweight film-type piezoelectric sensor on the body protector. In the case of an existing electronic body protector, all sensors and network device were concentrated on the body protector, so users need to purchase a set if they want it. On the other hand, the proposed system cloud can be used individually using a smart scoring WEP program. The effects of decreasing weight by up to 20% were compared with those of the existing system. Setting up a test facility is very difficult, so more study will be needed to analyze the effects of a hit.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.30 no.2C
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• pp.85-93
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• 2010

The shear stiffness has become an important design parameter to understand the soil behavior. In particular, the elastic moduli and void ratio has been considered as important parameters for the design of the geotechnical structures. The objective of this paper is the development of the penetration type Field Velocity and Resistivity Probe (FVRP) which is able to assess the elastic moduli and void ratio based on the elastic wave velocities and electrical resistivity. The elastic waves including the compressional and shear wave are measured by piezo disk elements and bender elements. And the electrical resistivity is measured by the resistivity probe, which is manufactured and installed at the tip of the FVRP. The penetration tests are carried out in calibration chamber and field. In the laboratory calibration chamber test, after the sand-clay slurry mixtures are prepared and consolidated. The FVRP is progressively penetrated and the data are measured at each 1 cm. The field experiment is also carried out in the southern part of Korea Peninsular. Data gathering is performed in the depth of 6~20 m at each 10 cm. The elastic moduli and void ratio are estimated based on the analytical and empirical solutions by using the elastic wave velocities and electrical resistivity measured in the chamber and field. The void ratios based on the elastic wave velocities and the electrical resistivity are similar to the volume based void ratio. This study suggests that the FVRP, which evaluates the elastic wave velocities and the electrical resistivity, may be a useful instrument for assessing the elastic moduli and void ratio in soft soils.