Non-equal-interval direct optimizing Verhulst model that x(n) be taken as initial value and its application

To overcome the deficiencies of the existing Verhulst GM(1,1) model, based on the existing grey theory, a non-equal-interval direct optimum Verhulst GM(1,1) model is built which chooses a modified n-th component x(n) of X(0) as the starting condition of the grey differential model. It optimizes a modified β value and the background value, and takes two times fitting optimization. The new model extends equal intervals to non-equal-intervals and is suitable for general data modelling and estimating parameters of the direct Verhulst GM(1,1). The new model does not need to pre-process the primitive data, nor accumulate generating operation (AGO) and inverse accumulated generating operation (IAGO). It is not only suitable for equal interval data modelling, but also for non-equal interval data modelling. As the new information is fully used and two times fitting optimization is taken, the fitting accuracy is the highest in all existing models. The example shows that the new model is simple and practical. The new model is worth expanding on and applying in data processing or on-line monitoring for tests, social sciences and other engineering sciences.

Study of time resolution by digital methods with a DRS4 module

A new Digital Pulse Processing（DPP） module has been developed, based on a domino ring sampler version 4 chip（DRS4）, with good time resolution for La Br3 detectors, and different digital timing analysis methods for processing the raw detector signals are reported. The module, composed of an eight channel DRS4 chip, was used as the readout electronics and acquisition system to process the output signals from XP20D0 photomultiplier tubes（PMTs）. Two PMTs were coupled with La Br3 scintillators and placed on opposite sides of a radioactive positron22 Na source for 511 ke V γ-ray tests. By analyzing the raw data acquired by the module, the best coincidence timing resolution is about 194.7 ps（FWHM）, obtained by the digital constant fraction discrimination（d CFD） method,which is better than other digital methods and analysis methods based on conventional analog systems which have been tested. The results indicate that it is a promising approach to better localize the positron annihilation in positron emission tomography（PET） with time of flight（TOF）, as well as for scintillation timing measurement,such as in TOF-？E and TOF-E systems for particle identification, with picosecond accuracy timing measurement.Furthermore, this module is more simple and convenient than other systems.

Time to Get Fit

China tries to boost citizen involvement in sports to become an international power in competitions Retired 56-year-old Beijing resident Chu Lirong stood outside the city’s National Stadium,the site of the Beijing