Zhifei Chen

Learn More
Program slicing is an important program analysis technique and now has been used in many fields of software engineering. However, most existing program slicing methods focus on static programming languages such as C/C++ and Java, and methods on dynamic languages like Python are rarely seen. Python, a typical dynamic object-oriented language, has been more(More)
—The dynamic features of programming languages are useful constructs that bring developers convenience and flexibility, but they are also perceived to lead to difficulties in software maintenance. Figuring out whether the use of dynamic features affects maintenance is significant for both researchers and practitioners, yet little work has been done to(More)
Python is widely used for web programming and GUI development. Due to the dynamic features of Python, Python programs may contain various unlimited errors. Dynamic slicing extracts those statements from a program which affect the variables in a slicing criterion with a particular input. Dynamic slicing of Python programs is essential for program debugging(More)
Python is widely used to create and manage complex, database-driven websites. However, due to dynamic features such as dynamic typing of variables, Python programs pose a serious security risk to web applications. Most security vulnerabilities result from the fact that unsafe data input reaches security-sensitive operations. To address this problem,(More)
Software has been changing during its whole life cycle. Therefore, identification of source code changes becomes a key issue in software evolution analysis. However, few current change analysis research focus on dynamic language software. In this paper, we pay attention to the fine-grained source code changes of Python software. We implement an automatic(More)
In this paper, an adaptive control technique is applied to controlling the chaotic behavior in thruster motor system for deepwater ocean robot. This chaotic oscillation has a direct impact on the stability, reliability and security of the robot. In addition, the proposed approach is also verified in the way of both flexibility and effectiveness, and a kind(More)
The 3dB beamwidth of the DOA estimation method based on the singular value decomposition of the signal phase matching principle (SVDSPM) was about 1/3 to 1/2 as much as that obtained by MUSIC at different SNR. However, the SVDSPM algorithm searched the optimal solutions with certain frequency, and the complexity and computational load of optimizing the(More)
One of the major problem in applying OFDM to underwater channels is that it is vulnerable to carrier frequency offset (CFO) caused by transceiver mismatch and/or Doppler shifts. And the loss of orthogonality due to the CFO effects must be compensated before the demodulation with discrete Fourier transform. This paper proposes a novel CFO estimation(More)
In addition to degrading misfolded and damaged proteins, the proteasome regulates the fate of cells in response to stress. The role of the proteasome in pro-inflammatory cytokine-induced human beta-cell apoptosis is unknown. Using INS-1, INS-1E and human islets exposed to combinations of IFNγ, IL-1β and TNFα with or without addition of small molecules, we(More)