Falsification of hybrid systems with symbolic reachability analysis and trajectory splicing

The falsification of a hybrid system aims at finding trajectories that violate a given safety property. This is a challenging problem, and the practical applicability of current falsification algorithms still suffers from their high time complexity. In contrast to falsification, verification algorithms aim at providing guarantees that no such trajectories exist. Recent symbolic reachability techniques are capable of efficiently computing linear constraints that enclose all trajectories of the system with reasonable precision. In this paper, we leverage the power of symbolic reachability algorithms to improve the scalability of falsification techniques. Recent approaches to falsification reduce the problem to a nonlinear optimization problem. We propose to reduce the search space of the optimization problem by adding linear state constraints obtained with a reachability algorithm. An empirical study of how varying abstractions during symbolic reachability analysis affect the performance of solving a falsification problem is presented. In addition, for solving a falsification problem, we propose an alternating minimization algorithm that solves a linear programming problem and a non-linear programming problem in alternation finitely many times. We showcase the efficacy of our algorithms on a number of standard hybrid systems benchmarks demonstrating the performance increase and number of falsifyable instances.     

Flattened chromatic dispersion in square photonic crystal fibers with low confinement losses

This research presents a simple index-guiding square photonic crystal fibers (SPCFs) that has a silica core surrounded by air hole with two different diameters. It is demonstrated that the designed two-different-size hole-arrayed index-guiding SPCFs has a ultra-flattened chromatic dispersion of 0 ± 0.9 ps/(nm·km) in a wavelength range of 1.34 to 1.61 μm and low confinement loss of less than 10⁻⁷ dB/m in a wavelength range of 1.2 to 1.7 μm. It has also been shown that the proposed SPCFs show reasonable dispersion tolerance.     

p73变异体研究现状及其在肿瘤放疗中的应用前景

p73基因是p53抑癌基因家族的新成员。 p73有两组蛋白异构体: TAp73和DNp73。 TAp73具有诱导细胞周期停滞和细胞凋亡的能力, 而DNp73却有与之相反的能力, 具有肿瘤促进作用。 对p73基因两面性的特点及研究进展作一综述。 最后结合重离子治疗肿瘤, 探讨了p73联合重离子治疗的新思路。 p73 was the first identified homologue of the tumor suppressor gene, p53. p73 has two groups of protein isoforms: TAp73 and DNp73. TAp73 can induce cell cycle arrest, resulting in the ability of apoptosis, however DNp73 has antagonistic property of a tumor promoting effect. In this paper, the dual roles of p73 gene and its research progress was reviewed. Finally, combined with heavy ion treatment of tumor, we explored some new ideas of p73 heavy ion joint therapy.     

大直径光纤端帽的制作与熔接

为了避免高功率光纤激光器输出的激光对双包层光纤端面造成损伤,设计并制作了光纤端帽。使用新型CO2激光器光纤熔接机完成了双包层光纤与端帽的熔接,研究了双包层光纤与端帽熔接的相关工艺与方法。利用高功率连续激光对端帽的性能进行了测试,实验结果表明,熔接有光纤端帽的双包层光纤可以承受507 W连续激光的输出并且没有发生损伤。熔接有端帽的光纤激光器的斜率效率为64.05%,光束质量与未熔接有端帽时相同。     

Graph splicing systems

In this paper, extended graph splicing systems are defined. It is shown that when strings are represented as linear graphs, any recursively enumerable set can be generated by an extended graph splicing system. It is also shown that the computational completeness of extended graph splicing systems can be proved under some constraints too.     

A proposed complementary pairing mode between single-stranded nucleic acids and β-stranded peptides: A possible pathway for generating complex biological molecules

A structure for a heterologous double-stranded molecule consisting of an oligoribonucleotide and a β-stranded oligopeptide, paired through complementary Watson-Crick-type hydrogen bonding, is proposed. The basis for such complementary pairings between oligoribonucleotides and oligopeptides is the close correspondence of the distances between the side-chains attached to the backbones of the two molecules. Both inter-nucleotide spacing and inter-amino acid side-chain spacing are approximately 3.4 Å. These kinds of interactions may have implications in protein-mediated-RNA splicing. Formation of a heterologous duplex through such a pairing mode could provide a simple coding mechanism for a reciprocal information transfer between oligonucleotides and oligopeptides. Because of its simplicity and versatility, allowing both specific and nonspecific coding, interactions via these kinds of pairing may have been relevant for prebiotic molecular evolution and for generating complex biological molecules.