Changyun Li

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This paper fouces on the spectrum handoff in cognitive radio which secondary users(SU) usually use the overlay spectrum acess scenario. We use the fuzzy logic and pridect a reserved channel table, when the spectrum handoff occur, SU can choose the available spetrum access quickly. Because of primary users(PU) appear uncertainty, the correctness of backup(More)
In new-type distributed software environment, the interactive behaviors produced by loosely-coupled software entities behave of emerging, dynamic, accidental, correlative and repeating properties. The paper tries to extract them into definable and relatively stable behavior analysis model between behavior process and corresponding effects. Software(More)
The rapid development and application of computer network has encouraged the application of GIS which is popular in a wide range and made the research of Web GIS be a focus. There are some problems about the browser of Web GIS. For example, the drawing efficiency is poor, it cannot support vector drawing directly and so on. In order to improve the client's(More)
The software is essentially replacing human beings to carry out some certain behavior and software credibility is mainly represented by its credible behavior, so it will be more direct and reliable to assess software credibility according to the information of software runtime behavior. The concept of behavior pattern is abstracted from the software(More)
—Multiple parallel transactions in new-type distributed software environment result in that the events produced by every transaction are randomly ranked. If the tokens of these events are incomplete or unavailable, it is difficult for software system to distinguish these events to actually belong to which transaction, corresponding transaction analysis and(More)
The monitoring and measurement results indicate that, severe influence may be brought to electromagnetic devices of power systems such as power transformers by DC bias effects. So, DC bias blocking device must be designed and manufactured to ensure the safety and stability of the power systems. In this paper, optimized analysis were done on the DC current(More)
To measure the pressure and temperature in downhole of oil well for a long term, a pressure and temperature gauge was especially designed. In order to reduce the gauge power consumption, a set of low power ICs, such as the 87lpc764 CPU, the AD7705 with a PGA and a digital filter, 24LC1025 EEPROM, PCF8583 timer were adapted; in additional, the intermittent(More)