We propose the first sound and complete learning-based compositional verification technique for probabilistic safety properties on concurrent systems where each component is an Markov decision process. Different from previous works, weighted assumptions are introduced to attain completeness of our framework. Since weighted assumptions can be implicitly represented by multi-terminal binary decision diagrams (MTBDD's), we give an L * -based learning algorithm for MTBDD's to infer weighted assumptions. Experimental results suggest promising outlooks for our compositional technique.
In order to evaluate the safe and stable operation of distribution network with the distributed photovoltaic (PV), the security of distribution network is researched. On the basis of electricity supply security, voltage quality and network losses, the index system of static security is established. The paper simulates the uncertainty and random characteristics of PV by OpenDSS. The typical scenes that PV accessed to the distribution network are designed. The paper summarizes the results of voltage fluctuation and network losses and uses indices to quantify it under different scenes. Based on the index system, the paper proposes some recommendations on PV permeability, interconnected locations, dispersion degrees and power factors when the distributed PV accessed to the distribution network.
Neoclassical tearing mode (NTM) can degrade plasma confinement or even cause disruptions in existing tokamaks. Stabilization of the / 3 / 2 m n = NTMs by radio frequency (rf) current is investigated by the modified Rutherford equation (MRE) in this paper. In a range of parameters, the required rf current for mode stabilization is obtained, which is linearly proportional to the bootstrap current density for both modulated current drive (MCD) and non-modulated current drive (NMCD), linearly (quadratically) to the radial width of the rf current for MCD (NMCD), and quadratically to the radial deviation of the rf current from the rational surface for both MCD and NMCD.
KeywordsNeoclassical Tearing Mode (NTM), Radio Frequency (RF) Current, Modified Rutherford Equation (MRE)
The Computer-based Testing (CBT) has developed successfully with its adoption by educators The authors of this paper point out the advantages and disadvantages of CBT by taking the case study to probe into the scoring algorithm in CBT The case is the experimental graduates of service learning ,who take some pre-tests and post-tests by CBT.
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