ZigBee networks, with their characteristics of high availability, low power consumption and cost-effective devices, are perfectly appropriate to construct Wireless Sensor Networks (WSNs). Also, the natures of WSN listed above bring significant benefits over traditional communication networks used in smart home systems. A smart home system is meant to improve the quality of life through offering various automated, interactive and comfortable services, such as sensing and communicating the family member’s health information with their doctors, or remotely controlling the appliances via cellular phones, emails etc. These critical services make the security of personal privacy and the authority of control commands vital issues in Smart Home environments. While the smart home system suffer from many attacks, the security of the smart home system become an important and hard problem. And the authentication is the first parclose to the security of the system. However, according to our analysis, most system fail to achieve the authentication between the user and the device, Which leading to the compromise of the whole system. In this paper, we analyze the authentication challenges between the user the device in WSNs and in smart home Systems. To thoroughly detect, defense and foresee the authentication vulnerabilities existing in smart home networks, we proposed a security evaluation technique based on attack graph generation. We discuss the distinction between the attack graphs deployed in traditional networks and in smart home networks. Furthermore, we apply this technique into an experiment, and the results prove its practicality. And we then suggest a widely used protocol to the smart home authentication system.
Time-interleaved analog-to-digital converter (ADC) architecture is crucial to increase the maximum sample rate. However, offset mismatch, gain mismatch, and timing error between time-interleaved channels degrade the performance of time-interleaved ADCs. This paper focuses on the gain mismatch and timing error. Techniques based on Discrete Fourier Transform (DFT) for estimating and correcting gain mismatch and timing error in an M-channel ADC are depicted. Numerical simulations are used to verify the proposed estimation and correction algorithm.
3
Dostęp do pełnego tekstu na zewnętrznej witrynie WWW
In a parallel time-interleaved data sampling system, timing and amplitude mismatches of this structure degrade the performance of the whole ADC system. In this paper, an adaptive blind synthesis calibration algorithm is proposed, which could estimate the timing, gain and offset errors simultaneously, and calibrate automatically. With no need of an extra calibration signal and redesign, it could efficiently and dynamically track the changes of mismatches due to aging or temperature variation. A fractional delay filter is developed to adjust the timing mismatch, which simplifies the design and decreases the cost. Computer simulations are also included to demonstrate the effectiveness of the proposed method.
JavaScript jest wyłączony w Twojej przeglądarce internetowej. Włącz go, a następnie odśwież stronę, aby móc w pełni z niej korzystać.