The firefighting robot system (FFRS) comprises several autonomous robots that can be deployed to fire disasters in petrochemical complexes. For autonomous navigation, the path planner should consider the robot constraints and characteristics. Specifically, three requirements should be satisfied for a path to be suitable for the FFRS. First, the path must satisfy the maximum curvature constraint. Second, it must be smooth for robots to easily execute the trajectory. Third, it must allow reaching the target location in a specific heading. We propose a path planner that provides smooth paths, satisfy the maximum curvature constraint, and allows a suitable robot heading. The path smoother is based on the conjugate gradient descent, and three approaches are proposed for this path planner to meet all the FFRS requirements. The effectiveness of these approaches is qualitatively and quantitatively evaluated by examining the generated paths. Finally, the path planner is applied to an actual robot to verify the suitability of the generated paths for the FFRS, and planning is applied to another type of robot to demonstrate the wide applicability of the proposed planner. 相似文献
Remote sensing is widely used in coastal management. Lyzenga's model has been traditionally used to explain the relationship between bottom surface reflectance and the radiance level measured by satellite. Due to its central assumption, this model lacks accuracy compared with the other radiative transfer models. Nonetheless, it enables, with a single and simple equation, representation of the multiple optical processes taking place in coastal areas. Mapping processes associated with this model may include radiometric correction, a technique previously pointed out as a major driver of mapping accuracy. Radiometric correction is generally based on a depth-invariant index, efficient for clear waters (Jerlov water type I to II) but largely unsuitable when transparency decreases (Jerlov water type II to III). In order to overcome this problem, we developed a new index for radiometric correction, which combines bathymetry data with attenuation coefficients. The improved efficiency of our model with regard to the traditional depth invariant index was demonstrated through two case studies: Funakoshi Bay (Japan; Jerlov water type II) and the Gabes Gulf part located off Mahares (Tunisia; Jerlov water type II to III). 相似文献
Temperature dependence of the Raman spectrum of lithium oxide single crystal has been measured over a temperature range of 80 to 1073 K. The frequency shift and the line width of the Raman spectrum in lithium oxide were about 531 and 4.5 cm-1 at 80 K, respectively. At 1073 K, the frequency shift and the line width attained the values of 464 and 112 cm-1, respectively. The strong temperature dependence of the frequency shift and line width was compared with data from some crystals with a fluorite structure. 相似文献
Various ion-beam etching characteristics of diamond and selectivity between diamond and spin-on-glass (SOG) were examined. The maximum selectivity of diamond and SOG was 12.7 in oxygen reactive ion-beam etching process at 100 V acceleration voltage. Using this etching condition and dot-shaped SOG mask, conical diamond field electron emitter arrays with 30 nm curvature radius, 2.58 μm base radius and 5.86 μm height were fabricated. 相似文献
A new method for an on-line monitoring system for the nuclear power plants has been developed utilizing the neural networks and the expert system. The integration of them is expected to enhance a substantial potential of the functionality as operators support.
The recurrent neural network and the feed-forward neural network with adaptive learning are selected for the plant modeling and anomaly detection because of the high capability of modeling for dynamic behavior. The expert system is used as a decision agent, which works on the information space of both the neural networks and the human operators. The information of other sensory signals is also fed to the expert system, together with the outputs that the neural networks generate from the measured plant signals. The expert system can treat almost all known correlation between plant status patterns and operation modes as a priori set of rules.
From the off-line test at Borssele Nuclear Power Plant (PWR 480 MWe) in the Netherlands, it was shown that the neuro-expert system successfully monitored the plant status. The expert system worked satisfactorily in diagnosing the system status by using the outputs of the neural networks and a priori knowledge base from the PWR simulator. The electric power coefficient is simultaneously monitored from the measured reactive and active electric power signals. 相似文献
Microbial reduction and intracellular precipitation of gold was achieved at 25 °C and pH 7 by using the mesophilic anaerobic bacterium Shewanella algae with H2 as the electron donor. The reductive precipitation of gold by S. algae was a fast process: 0.1–1 mol/m3 AuCl4− ions were completely reduced to insoluble gold within 30 min. The biogenic precipitates were crystalline gold nanoparticles of 10–20 nm present in the periplasmic space. The reducing power of S. algae at 3.2 × 1015 cells/m3 and 25 °C was comparable to that of aqueous citric acid solution (chemical reductant) at 20 mol/m3 and 50 °C. The intracellular recovery of gold is potentially attractive as an environmentally friendly alternative to conventional methods. 相似文献
Appropriately substituted 2,3-dihydro-7H-thiazolo[3,2-a]pyrimidin-7-ones 9-12 and 18 were considered as annulated analogues of HEPT (1-[(2-hydroxyethoxy)methyl]-6-(phenylthio)-thymine), and some of these compounds were also found active against HIV-1, the most active one being 2,3-dihydro-5-[(3,5-dimethylphenyl)methyl]-3-ethoxy-6-ethyl-7H- thiazolo[3,2-a]pyrimidin-7-one (10b). S-Alkylation of 5-alkyl-6-(arylmethyl)-2-thiouracils 1-4 was performed with 2-bromoacetaldehyde acetals to furnish the S-[bis(alkoxy)ethyl] derivatives 5-8 and with allyl bromide to furnish S-allyl derivatives 17. The target compounds 9-12 were obtained by an N1 regioselective intramolecular cyclization reaction of silylated 5-8 using trimethylsilyl trifluoromethanesulfonate (TMS triflate) as the catalyst. Treatment of the S-allyl derivatives 17 with bromine in dry methylene chloride afforded the 3-(bromomethyl) derivatives 18. 相似文献
We have investigated transformation with heterologous DNA as a method for insertional mutagenesis of Aspergillus fumigatus. Two methods, polyethylene glycol-mediated transformation of protoplasts and electroporation of germinating spores, were used to establish conditions leading to single-copy integration of transforming DNA at different genomic sites. We have assessed the effect of restriction enzyme-mediated integration (REMI) for both methods. Non-REMI protoplast transformation led to integration of multiple copies of transforming DNA in the majority of transformants. Results of REMI with protoplast transformation varied depending on the enzyme used. Low concentrations of several restriction enzymes stimulated transformation, but of ten enzymes investigated only REMI with XhoI and KpnI resulted in single-copy integration of transforming DNA for the majority of transformants. For protoplast transformation with XhoI- or KpnI-based REMI, 50% and 76% of insertions, respectively, were due to integrations at a genomic enzyme site corresponding to the enzyme used for REMI. Electroporation of spores without addition of restriction enzyme resulted in a high transformation efficiency, with up to 67% of transformants containing a single copy of transforming DNA. In contrast to protoplast transformation, electroporation of spores in the presence of a restriction enzyme did not improve transformation efficiency or lead to insertion at genomic restriction sites. Southern analysis indicated that for both protoplast transformation with REMI using KpnI or XhoI and for electroporation of spores without addition of restriction enzymes, transforming DNA inserted at different genomic sites in a high proportion of transformants. 相似文献