Fang Xianwen

A Study about the Mapping of Process- Processor based on Petri Nets

In the design and analysis of discrete event systems, the validation of their models is often addressed via simulation. Petri nets have been applied widely. Lookahead computation is a good method that improves the distributed simulation performance of Timed Transition Petri Nets (TTPN). The approach is based on a part of optimism computed on the prediction time each logical process can determine for its advancement. Timed Petri nets meet these requirements, and use the lookahead to analyze the TTPN model for finding the concurrency and blocking structure, thereby making certain the logical process (LP). Based on the specialties of lookahead, the lookahead was applied in parallel simulation, and acquire the sufficient condition about the TTPN model existing concurrency. According to the condition, parallel program can be partitioned into several logical processes, and the partition algorithm that can decide quickly the mapping project on the mapping process-processor is presented.

Majorana fermions detection based on acoupled quantum dot-nanomechanical resonator system

Motivated by a recent experiment providing evidence for Majorana zero modes in iron (Fe) chains on the superconducting Pb surface, in the present work, an optical method for probing Majorana fermions is proposed theoretically, which is very different from the current tunneling spectroscopy experiments with electrical means. The optical detection proposal consists of a hybrid quantum dot-nanomechanical resonator system driven by one strong pump field and one weak probe field. With the optical means, the signal in the coherent optical spectrum indicates a distinct signature of Majorana fermions in the end of iron chains when the quantum dot coupled to Majorana fermions. In addition, an optical scheme for determining the coupling strength between Majorana fermions and the quantum dot is also introduced, which affords a straightforward method to measure such coupling. We further investigate the role of the nanomechanical resonator in the hybrid system. The vibration of the nanomechanical resonator behaving as a phonon cavity will enhance the exciton resonance spectrum, which is robust for the detection of Majorana fermions. This optical scheme affords a potential supplement to detecte Majorana fermions and supports to use Majorana fermions in Fe chains as qubits for potential applications in quantum computing devices.

The Study on Data Distribution Management Based on Petri Net

To the research on the high level architecture (HLA) in the data distribution management (DDM), the essential target is to enhance the data filter efficiency, to reduce computing quantity at the same time, and to provide well scalability for some kind of distribution simulation application under the HLA standard. The colored Petri net has the characteristic that including the basic Petri net and the higher-level language, which has the large superiority to the distribution simulation in data distribution management. Using the data distribution mechanism based on the colored Petri net, the data filters can be well carried out, the data filter efficiency can be enhanced, and the success rate of the data dispatching and receiving can be guaranteed. The simulation experiment result indicated that, the data distribution mechanism based on the colored Petri net is better than the region matching method.