ABSTRACT
A discrete time feedback control system model based on a multi-router network has been presented. The model can be described by a set of recurrence equations. The numerical examples about the bifurcation of average and instantaneous queue size along with the variety of RED control parameter are shown. The simulate experiments about those of the RED control parameters are also presented. All of these results show that instability in TCP-Reno traffic under RED can be induced by the inherent nonlinear behavior of the network.
ABSTRACT
The expert system is an important field of the artificial intelligence. The traditional interface of the expert system is the command, menu and window at present. It limits the application of the expert system and embarrasses the enthusiasm of using expert system. Combining with the study on the expert system of network fault diagnosis, the natural language interface of the expert system has been discussed in this article. This interface can understand and generate Chinese sentences. Using this interface, the user and field experts can use the expert system to diagnose the fault of network conveniently. In the article, first, the extended production rule has been proposed. Then the methods of Chinese sentence generation from conceptual graphs and the model of expert system are introduced in detail. Using this model, the network fault diagnosis expert system and its natural language interface have been developed with Prolog.
ABSTRACT
Objective To assess the efficiency and methods of the interventional management in acute mesenteric venous thrombosis (AMVT). Methods Fifteen patients with AMVT who diagnosed by imageology were treated by interventional procedures. Eight patients were treated by transcatheter superior mesenteric artery thrombolysis with urokinase, 5 cases by percutaneous transhepatic treatment, 2 cases by transjugular intrahepatic portosystemic shunt approach. Results The technical success was achieved in all the 15 cases without complications. The majority of the thrombus was cleared by interventional procedures and flow restorated on the angiograms. All the patients with follow-up from 10 to 22 months showed no recurrence. Conclusion The minimally invasive interventional techniques are safe and effective in the treatment of mesenteric venous thrombosis without necrosis.
ABSTRACT
Tests of effects on life of adult fruit fly of Cordyceps polysaccharides from submerged fermentation products showed that the polysaccharides had the activity against senescence. Some samples had very notable effect among which polysaccharides from AT01 (both intracellular and extracellular) had the best effects.