A Real-time Range Finding System with Binocular Stereo Vision

To acquire range information for mobile robots, a TMS320DM642 DSP-based range finding system with binocular stereo vision is proposed. Firstly, paired images of the target are captured and a Gaussian filter, as well as improved Sobel kernels, are achieved. Secondly, a feature-based local stereo matching algorithm is performed so that the space location of the target can be determined. Finally, in order to improve the reliability and robustness of the stereo matching algorithm under complex conditions, the confidence filter and the left-right consistency filter are investigated to eliminate the mismatching points. In addition, the range finding algorithm is implemented in the DSP/BIOS operating system to gain real-time control. Experimental results show that the average accuracy of range finding is more than 99% for measuring single-point distances equal to 120cm in the simple scenario and the algorithm takes about 39ms for ranging a time in a complex scenario. The effectivity, as well as the feasibility, of the proposed range finding system are verified

Generalized Volume-Complexity for RN-AdS Black Hole

The connection between quantum information and quantum gravity has captured the imagination of physicists. Recently, a broad new class of gravitational observables have been proposed to provide new possibilities for holographic complexity [Phys. Rev. Lett. 128 (2022) 081602], which is an extension of volume in the Complexity=Volume proposal. In this paper, we investigate generalized volume-complexity for the 4-dimensional Reissner-Nordstr\"{o}m-AdS black hole. These new observables satisfy the characteristic of the thermofield double state, i.e., they grow linearly in time on the late stage. We find that there are multiple extremal hypersurfaces anchored at a certain boundary time. In other words, for the same boundary time, more than one observable (generalized volume) can exist in the bulk. The size relationship of the observables on the two hypersurfaces changes over time. This will result in the substitution of the maximum extreme hypersurface which is dual to the complexity of the thermofield double state. We call the time when one hypersurface replaces another to become the largest extreme hypersurface the turning time $\tau _{turning}$. That is, a hypersurface dual to the complexity of the thermofield double state defined on the boundary jumps from one branch to another. This discontinuous jump is highly reminiscent of a phase transition, and the turning time denotes the moment at which this phase transition occurs. Our findings propose a discontinuous variation in bulk physics that is dual to the complexity of the thermofield double state defined on the boundary.Comment: 20 pages, 9 figure

Chaos and multifold complexity for an inverted harmonic oscillator

We examine the multifold complexity and Loschmidt echo for an inverted harmonic oscillator. We give analytic expressions for any number of precursors, implementing multiple backward and forward time evolutions of the quantum state, at the leading order in the perturbation. We prove that complexity is dominated by the longest permutation of the given time combination in an alternating ``zig-zag'' order, the exact same result obtained with holography. We conjecture that the general structure for multifold complexity should hold true universally for generic quantum systems, in the limit of a large number of precursors.Comment: 24 pages, 9 figure

Holographic Complexity with Different Gravitational Observables

We investigate a more general conjugate regarding the holographic complexity: complexity equals any gravitational observables [Phys. Rev. Lett. 128, 081602 (2022)], which is an extension of the complexity equals volume proposal. These gravitational observables are referred to as generalized volumes.In this paper, we investigate the generalized volume-complexity for the planar anti-de Sitter black hole and the charged Banados-Teitelboim-Zanelli black hole with different gravitational observables. We note that when anchored at the same boundary time, there may be more than one extremal hypersurface. Determining which one can represent the complexity has become a question that requires further discussion. For the complexity equals volume proposal, the complexity is thought to be proportional to a maximal volume of a hypersurface anchored on the boundary time slice. However, in our research, we find that the size relationship of the gravitational observables on these extremal generalized volume slices are not fixed, but change over time. We refer to this moment of the change as the turning time.Comment: 18 pages, 11 figure

(E)-N-Benzyl­ideneadamantan-1-amine

In the title compound, C17H21N, the dihedral angle between the benzene ring and the imine group (—N=) is 5.1 (4)°. In the adamantane group, the C—C—C bond angles range from 107.88 (19) to 111.33 (17)°. Only weak van der Waals inter­actions contribute to the contribute to the packing of the molecules in the crystal.

Ozone and haze pollution weakens net primary productivity in China

Atmospheric pollutants have both beneficial and detrimental effects on carbon uptake by land ecosystems. Surface ozone (O3) damages leaf photosynthesis by oxidizing plant cells, while aerosols promote carbon uptake by increasing diffuse radiation and exert additional influences through concomitant perturbations to meteorology and hydrology. China is currently the world’s largest emitter of both carbon dioxide and short-lived air pollutants. The land ecosystems of China are estimated to provide a carbon sink, but it remains unclear whether air pollution acts to inhibit or promote carbon uptake. Here, we employ Earth system modeling and multiple measurement datasets to assess the separate and combined effects of anthropogenic O3 and aerosol pollution on net primary productivity (NPP) in China. In the present day, O3 reduces annual NPP by 0.6 Pg C (14 %) with a range from 0.4 Pg C (low O3 sensitivity) to 0.8 Pg C (high O3 sensitivity). In contrast, aerosol direct effects increase NPP by 0.2 Pg C (5 %) through the combination of diffuse radiation fertilization, reduced canopy temperatures, and reduced evaporation leading to higher soil moisture. Consequently, the net effects of O3 and aerosols decrease NPP by 0.4 Pg C (9 %) with a range from 0.2 Pg C (low O3 sensitivity) to 0.6 Pg C (high O3 sensitivity). However, precipitation inhibition from combined aerosol direct and indirect effects reduces annual NPP by 0.2 Pg C (4 %), leading to a net air pollution suppression of 0.8 Pg C (16 %) with a range from 0.6 Pg C (low O3 sensitivity) to 1.0 Pg C (high O3 sensitivity). Our results reveal strong dampening effects of air pollution on the land carbon uptake in China today. Following the current legislation emission scenario, this suppression will be further increased by the year 2030, mainly due to a continuing increase in surface O3. However, the maximum technically feasible reduction scenario could drastically relieve the current level of NPP damage by 70 % in 2030, offering protection of this critical ecosystem service and the mitigation of long-term global warming

Microsatellites reveal a strong subdivision of genetic structure in Chinese populations of the mite Tetranychus urticae Koch (Acari: Tetranychidae)

Contact: [email protected] audienceBACKGROUND: Two colour forms of the two-spotted spider mite (Tetranychus urticae Koch) coexist in China: a red (carmine) form, which is considered to be native and a green form which is considered to be invasive. The population genetic diversity and population genetic structure of this organism were unclear in China, and there is a controversy over whether they constitute distinct species. To address these issues, we genotyped a total of 1,055 individuals from 18 red populations and 7 green populations in China using eight microsatellite loci. RESULTS: We identified 109 alleles. We found a highly significant genetic differentiation among the 25 populations (global F-ST = 0.506, global F-ST({ENA}) = 0.473) and a low genetic diversity in each population. In addition, genetic diversity of the red form mites was found to be higher than the green form. Pearson correlations between statistics of variation (AR and H-E) and geographic coordinates (latitude and longitude) showed that the genetic diversity of the red form was correlated with latitude. Using Bayesian clustering, we divided the Chinese mite populations into five clades which were well congruent with their geographic distributions. CONCLUSIONS: Spider mites possess low levels of genetic diversity, limit gene flow between populations and significant and IBD (isolation by distance) effect. These factors in turn contribute to the strong subdivision of genetic structure. In addition, population genetic structure results don't support the separation of the two forms of spider mite into two species. The morphological differences between the two forms of mites may be a result of epigenetic effects