Collision risk assessment based artificial potential field approach for multi-ships avoidance

1037-1047Artificial potential field (APF) is widely used for obstacles avoidance of autonomous surface vessel (ASV). However, its performance is poor for the case that the ASV encounters multiple ships. The collision may happen since the APF method is only taking distance and velocity into account. To solve this problem, a collision risk assessment based approach is proposed. A fuzzy logic system is applied to assess the collision risk with distance of close point of ppproaching (DCPA) and time of close point of approaching (TCPA). The collision risk is used to modify the APF for the ASV to avoid multiple ships. A critical encounter scenario is simulated to test the proposed approach. The simulation results indicate that the proposed method overcomes the problem to help an ASV successfully avoids the ship collision

Geometric bionics: Lotus effect helps polystyrene nanotube films get good blood compatibility

Various biomaterials have been widely used for manufacturing biomedical applications including artificial organs, medical devices and disposable clinical apparatus, such as vascular prostheses, blood pumps, artificial kidney, artificial hearts, dialyzers and plasma separators, which could be used in contact with blood^1^. However, the research tasks of improving hemocompatibility of biomaterials have been carrying out with the development of biomedical requirements^2^. Since the interactions that lead to surface-induced thrombosis occurring at the blood-biomaterial interface become a reason of familiar current complications with grafts therapy, improvement of the blood compatibility of artificial polymer surfaces is, therefore a major issue in biomaterials science^3^. After decades of focused research, various approaches of modifying biomaterial surfaces through chemical or biochemical methods to improve their hemocompatibility were obtained^1^. In this article, we report that polystyrene nanotube films with morphology similar to the papilla on lotus leaf can be used as blood-contacted biomaterials by virtue of Lotus effect^4^. Clearly, this idea, resulting from geometric bionics that mimicking the structure design of lotus leaf, is very novel technique for preparation of hemocompatible biomaterials

Bifurcations in a Nonlinear Dynamical Model between Western Pacific Subtropical High Ridge Line Index and Its Summer Monsoon Impact Factors

The western Pacific subtropical high (WPSH) is closely related to Asian climate. Previous studies have shown that a precise dynamical model focusing on the interaction between WPSH and other summer monsoon factors has not been developed. Based on the concept of dynamical model reconstruction, this paper reconstructs a nonlinear dynamical model of subtropical high ridge line (SHRL) and summer monsoon factors from recent 20 years data. Then, using genetic algorithm (GA), model inversion and model parameter optimization are carried out. Based on the reconstructed dynamical model, dynamical characteristics of SHRL are analyzed and an aberrance mechanism is developed, in which the external forcings resulting in the WPSH anomalies are explored. Results show that the configuration and diversification of the SHRL equilibriums have better represented the abnormal activities of the SHRL in short and medium term. Change of SHRL brought by the combination of equilibriums is more complex than that brought by mutation. The mutation behavior from high-value to low-value equilibriums of the SHRL in summer corresponds with the southward drop of the SHRL. The combination behavior of the two steady equilibriums corresponds with disappearance of the “double-ridge” phenomenon of WPSH. Dynamical mechanisms of these phenomena are explained

First record of the genus Rutylapa from China, with description of a new species (Diptera: Keroplatidae)

This is the first report of the genus Rutylapa Edwards, 1929, from China. Rutylapa longa Cao & Xu sp. n. is described and figured, and it is compared to the other Palaearctic species of the genus, R. ruficornis Zetterstedt

An increase in the cerebral infarction area during fatigue is mediated by il-6 through an induction of fibrinogen synthesis

OBJECTIVES: Our study aimed to investigate the impact of fatigue on the severity of stroke and to explore the underlying mechanisms. METHODS: Fatigued male rats underwent middle cerebral artery occlusion and the infarcted brain area was determined. Then, coagulation parameters were assessed in the fatigued group and a control group. In addition, the level of fibrinogen was determined in rats deprived of sleep for various numbers of days. To study whether interleukin-6 was involved in fibrinogen synthesis during fatigue, we also measured levels of interleukin-6 in rats deprived of sleep for various numbers of days. Furthermore, brain injury by middle cerebral artery occlusion was measured in wild-type mice, interleukin-6-/- mice and wild-type mice treated with bezafibrate. RESULTS: More severe cerebral infarction was observed in the fatigued rats, resulting in an infarct ratio of 23.4%. The infarct ratio was significantly increased in the fatigued rats compared with that in the control group (8%,