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Key Technology Development and Application of High-Security UHF RFID Systems
Pan Tiejun,Zheng Leina,Wang Ming,Zhu Xiaodong 보안공학연구지원센터 2016 International Journal of Database Theory and Appli Vol.9 No.10
Threats in Internet of things are ubiquitous such as counterfeiting, product piracy and product recall. China is no exception to this trend. The reader SoC (system on chip) chip of Ultra high frequency (UHF) Radio Frequency Identification is the key technology to solve these threats. Due to RF technology, tag data is read and written through wireless transmission directly in the air. In order to avoid tag theft and related backstage database attack, we provide UHF High Security System (UHS-HSS) to prevent the tag data monitoring in third party equipment. UHF-HSS regard UHF RFID reader SoC chip technology as the technology foundation provides chip level security solutions, system level information security service and industry level security applications for the IOT. This paper introduces a complete set of software platforms based on UHF RFID sensors including the underlying Linux operating system and related device driver, IOT platform technology, RFID middle-ware technology and software platform application. It solves the critical problem of security and reliability of UHF RFID applications for the national economy, which is of a great significance for the development of China's Internet of Things technology.
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A Method Based on Spectrum Superposition for Minimizing the Hazards of Blasting Vibration
Tiejun Tao,Sipeng Wan,Liansheng Liu,Tongyan Pan 대한토목학회 2021 KSCE JOURNAL OF CIVIL ENGINEERING Vol.25 No.5
The selection of delay time will directly affect the effect of vibration reduction in millisecond delay blasting. The commonly used frequency spectrum control methods have some problems such as the difficulty of seed wave selection and the complexity of nonlinear superposition model. Based on the principle of waveform linear superposition, this study proposes a new spectrum superposition method for minimizing the vibration hazards in an open deep-hole bench blasting. This method, with no need to select the seed waves, mainly uses the ratio of the Fourier spectrum of the combined vibration waveform and the single hole vibration waveform to quantify the suppressed vibration. By defining the suppression ratio K, the suppression ratio with frequency range of 10 − 60 Hz under different delay times was calculated, and the theoretical optimal vibration reduction delay time value of 10 − 15 ms was given. A high precision digital electronic detonator was used to verify the proposed spectrum superposition method. The test results show that the best delay time of field vibration reduction is 5 − 10 ms, which is lower than the theoretical best delay time of 10 − 15 ms. It is the authors’ belief that this phenomenon is mainly caused by the joints and cracks in the rock mass, which will prolong the actual superposition time of blasting seismic waves between adjacent holes. In addition, it is found that there is a negative correlation between the delay time and the main vibration frequency, which is mainly caused by the low-pass filtering characteristic of rock medium. In order to minimize the probability of resonance failure, an optimal delay of 5 ms based on the main vibration frequency was given.
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