Wuhan University Journal of Natural Sciences 

About: Wuhan University Journal of Natural Sciences is an academic journal published by Springer Science+Business Media. The journal publishes majorly in the area(s): Encryption & Computer science. It has an ISSN identifier of 1007-1202. Over the lifetime, 3190 publications have been published receiving 9526 citations.

The new methodology

Abstract: In the past few years there’s been a rapidly growing interest in “lightweight” methodologies. Alternatively characterized as an antidote to bureaucracy or a license to hack they’ve stirred up interest all over the software landscape. In this essay I explore the reasons for lightweight methods, focusing not so much on their weight but on their adaptive nature and their people-first orientation. I also give a summary and references to the processes in this school and consider the factors that should influence your choice of whether to go down this newly trodden path.

PANDA software and its preliminary result of positioning and orbit determination

Abstract: PANDA (Position And Navigation Data Analyst) software is designed for data analysis of different satellite positioning and navigation systems, such as SLR, GPS and the future GALIEO. The software has being developed since 2000 at GPS Research Center of Wuhan University. A brief introduction of the software and its developing progress are given at first, and then the results of static positioning and GPS satellite orbit determination archived with PANDA are presented in this paper.

Detection of structural damage through changes in frequency

Abstract: Among all the structural vibration characteristics, natural frequencies are relatively simple and accurate to measure, and provide the structural global damage information In this paper, the feasibility of using only natural frequencies to identify structural damage is exploited by adopting two usual approaches, namely, sensitivity analysis and neural networks Some aspects of damage detection such as the problem of incomplete modal test data and robustness of detection are considered A laboratory tested 3-storey frame is used to demonstrate the possibility of frequency-based damage detection techniques The numerical results show that the damaged element can be correctly localized and the content of damage can be identified with relatively high degree of accuracy by using the changes in frequencies

Reference station network based RTK systems-concepts and progress

Abstract: The limitation of single base “real-time kinematic” (RTK) techniques is the distance between base receiver and the rover receiver due to distance-dependent biases, namely orbit bias, ionosphere bias and troposphere bias. Techniques have been developed to overcome this distance dependence using a network of GPS reference stations spread over a wide geographic area. Because the measurement biases will be modelled and corrected for, the positioning accuracy will be almost independent of the inter-receiver distance. Since the mid-1990s investigators have been investigating the optimal means of processing reference receiver data, and then providing ‘correction’ information to users, in real-time. This technique is now generally referred to as Network-RTK. In 1993 the International Association of Geodesy (IAG) established a Special Study Group on “Wide Area Modelling for Precise Satellite Positioning” . This paper focusses on the progress made during the last few years in designing Network-RTK architectures and the associated data processing algorithms and issues. Although many university investigators have been researching the fundamental challenges in functional and stochastic modelling, currently there is only one commercially available Network-RTK product, the Trimble VRS. However, with the use of the Internet as the primary data communication link, it is predicted that many more implementations of Network-RTK will come ‘online’, at various sites around the world, over the next few years.

Keyword extraction based on tf/idf for Chinese news document

Abstract: Keyword extraction is an important research topic of information retrieval. This paper gave the specification of keywords in Chinese news documents based on analyzing linguistic characteristics of news documents and then proposed a new keyword extraction method based on tf/idf with multi-strategies. The approach selected candidate keywords of uni-, bi-and tri- grams, and then defines the features according to their morphological characters and context information. Moreover, the paper proposed several strategies to amend the incomplete words gotten from the word segmentation and found unknown potential keywords in news documents. Experimental results show that our proposed method can significantly outperform the baseline method. We also applied it to retrospective event detection. Experimental results show that the accuracy and efficiency of news retrospective event detection can be significantly improved.