Subjects: Astronomy >> Astrophysical processes submitted time 2021-07-30 Cooperative journals: 《天文研究与技术》
Abstract： GNSS（Global Navigation Satellite System，全球导航卫星系统）接收机在接收到卫星信号后，经过捕获、跟踪，得到码相位与载波相位两个基本的测量值。然后通过测量值计算卫星与接收机之间的距离。载波相位测量值比码相位测量值具有更高的测量精度，但由于载波相位测量值具有计算整周模糊度的问题，在实际的计算当中得到高精度的相位测量结果需要付出更多的计算代价。因此，在实际应用中，得到更高精度的码相位测量结果具有更实际的意义。本文在基于相位条纹的技术基础上，通过提取互相关功率谱，提出一种更高精度的码相位测量方法，得到更高精度的码相位测量值，从而得到更高精度的码伪距测量结果，并通过实际的GNSS的信号验证了本方法的有效性。
Subjects: Computer Science >> Integration Theory of Computer Science submitted time 2018-04-12 Cooperative journals: 《计算机应用研究》
Abstract： With the development of mobile internet, malicious code for Android platform has increased dramatically. And face up to the mount of Android malware, the current analyzing methods are focusing on the characteristic-based detecting, which is lack of a uniform systematic analyzing and classifying method. To resolve this status, this paper proposed the definition of Android malware gene to analyzing malware via binary sequence including function and information. And based on the characteristics of Android applications, this paper extract software gene from code fragment and resource fragment. Therein, the code fragment gene is a kind of formalization of use-def chains. Moreover, this paper proposed a detecting framework and a classifying framework based on malware gene. And this paper utilized a machine learning method, support vector machine(SVM) , in the frameworks. In evaluation, the detecting rate and classification correct rate are both high in those frameworks, with a recall rate of 98.37%. It proves the effect of malware gene in analyzing the homology of Android malicious code.
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