The number of passenger cars equipped with a smart key system continues to increase due to the convenience of the system. A smart key system allows the driver to enter and start a car without using a mechanical key through a wireless authentication process between the car and the key fob. Even though a smart key system has its own security scheme, it is vulnerable to the so-called relay attacks. In a relay attack, attackers with signal relaying devices enter and start a car by relaying signals from the car to the owner's fob. In this study, a method to detect a relay attack is proposed. The signal strength is used to determine whether the signal received is from the fob or the attacker's relaying devices. Our results show that relay attacks can be avoided by using the proposed method.
In this study, the potash glass beads of 281 samples in 30 sites analyzed until now were classified according to the chemical composition. And the color, size, manufacturing technique and distribution period were compared. Korea potash glass beads are divided into 3 types depending on the stabilizer content. I, II type is the CaO and Al2O3 content of less than 5%. Relatively, I type has a high CaO and II type has a high Al2O3. In contrast, III type comprises more than CaO 5%. I, II type is the saltpetre, III type is estimated using plant ash as row material of flux. A review of the properties by type, I type is cobalt blue, copper blue and purple beads. The outer diameter is sized to the range 1.4 ~ 7.4mm. Also it was produced by the drawing technique. It was used continuously from BC 1C until around AD 6C. On the other hand, II type is outer diameter of 1.9 ~ 3.6mm and a copper blue beads. manufacturing technique is the same as the I type. This seems to have been in use since around AD 1C to 4C. Finally, III type is brown, colorless, amber beads and an outer diameter of about 10mm. It was formed by winding technique and appeared in the tombs of
The extensive archaeological remains at the Baekje Kingdom site of Wanggung-ri, Iksan, in the South Jeolla Province, Korea, include a seventh century workshop area that was later covered by the construction of a Buddhist temple. Remains of glass, gold, and bronze artefacts, and the ceramic crucibles used in the working of these materials, provide evidence for a multi-craft, high-temperature technology. We will report the results of both chemical compositional and lead isotope analyses for Wanggung-ri glass, which is among the earliest lead-silica glass type in East Asia, as well as review the evidence for primary glass production at Wanggung-ri.
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