Subjects: Statistics >> Social Statistics submitted time 2024-03-27 Cooperative journals: 《中国科学院院刊》
Abstract： Sanjiangyuan National Park, is one of the first batch of national parks in China, and serves as the largest national park in China. As an important ecological security barrier and a alpine biological germplasm resource base, it has significant conservation value in China and even in the world. Lots of protocols have been taken aiming at ecological tacking protection issues including loss of biodiversity and wildlife habitats, degradation of alpine grassland and overgrazing in Sanjiangyuan National Park. It promotes the implementation of major ecological restoration projects, and has formed the Sanjiangyuan National Park Biodiversity Conservation and Ecological Protection Program with the basics of the theory of grassland multifunctional target management and the new technologies of biodiversity protection. It has formed a new paradigm of scientific research support for biodiversity conservation and improvement of livelihoods for herds in the park, providing practical solutions for the construction of China’s ecological civilization, Chinese wisdom for the construction of national parks around the world, and Chinese solutions for global biodiversity conservation.
Subjects: Psychology >> Social Psychology submitted time 2023-03-27 Cooperative journals: 《心理学报》
Abstract： Both audiovisual integration and inhibition of return (IOR) can facilitate the processing of sensory information, such as enhancing the perceptual processing. Previous studies found that IOR decreased the audiovisual integration at previously attended locations. Several hypotheses have been put forward to explain the effect of IOR on audiovisual integration: perceptual sensitivity, spatial uncertainty, and differences in unimodal signal strength. In present study, we used cue-target paradigm and manipulated the SOA conditions (400~600 ms vs. 1000~1200 ms) to investigate how audiovisual integration would be modulated by IOR induced by visual exogenous spatial cues.The current study was a 2 (SOA conditions: 400~600 ms, 1000~1200 ms) × 3 (target modalities: visual, auditory, audiovisual) × 2 (cue validities: cued, uncued) factorial design. Twenty-seven undergraduate students were recruited as paid volunteers from a university. The visual (V) target was a red and white block (1°×1°). The auditory (A) target (duration of 100 ms) was a 1000 Hz sinusoidal tone presented by speakers. The audiovisual (AV) target was composed by the simultaneous presentation of both the visual and the auditory stimuli. At the beginning of each trial, the fixation stimulus was presented for 800~1000 ms in the center of the display. Following the fixation stimulus, a visual white square served as a exogenous cue was presented for 50 ms at the left or right location randomly. Then, the fixation stimulus was randomly presented for 150~250/450~550 ms, which was followed by a central cue with a delay of 50 ms. Before the target (100 ms) occurrence, the fixation stimulus randomly appeared again for 150~250/450~550 ms. Thus, the SOA between the peripheral cue and the target was completed in 400~600/1000~1200 ms. The target (A, V, or AV) randomly appeared (6/7) for 100 ms in the left or right locations, or no stimulus appeared (1/7). During the experiment, participants were instructed to respond to the target stimulus at any possible locations by pressing a response button as quickly and accurately as possible.The results showed that the responses to AV targets were faster than V or A targets, indicating the appearance of the bimodal advancement effect. A smaller magnitude of audiovisual IOR as compared to visual IOR was found whether it’s in short or long SOA conditions. In addition, visual IOR effect was significantly reduced under the long SOA condition compared with the short SOA condition while the audiovisual integration effect increased by SOA. The results of the relative multisensory response enhancement (rMRE), race model (probability difference) and positive area under the curve (pAUC) showed that audiovisual integration decreased at cued compared to uncued locations under the short SOA condition but not the long SOA condition. Based on the aforementioned findings, it is assumed that visual IOR decreased the audiovisual integration in the short SOA, and audiovisual integration would be modulated by different SOA conditions. The current result supported the hypothesis of differences in unimodal signal strength.
Subjects: Psychology >> Social Psychology submitted time 2023-03-27 Cooperative journals: 《心理学报》
Abstract： Previous studies usually used the instruction to control the attention of the participants to different spatial locations to investigate the influence of endogenous spatial attention on the audiovisual integration, which found that endogenous spatial attention enhanced audiovisual integration. However, in reality, it is difficult to assign attention in an all-or-none manner. In present study, we used endogenous spatial cue-target paradigm to investigate the effect of endogenous spatial cue validity on audiovisual integration.The current study was a 2 (cue validities: valid, invalid) � 3 (target modalities: visual, auditory, audiovisual) factorial design. A total of 62 undergraduate students were recruited as paid volunteers. Experiment 1 recruited 35 participants (5 males; age range: 18~26 years; mean age: 21.26 � 1.77 years). Experiment 2 recruited 27 participants (6 males; age range: 19~25 years; mean age: 22.19 � 1.75 years). The visual (V) target was a white pentagonal asterisk block (2白2�). The auditory (A) target was a 1600 Hz sinusoidal tone presented by speakers. The audiovisual (AV) target was composed by the simultaneous presentation of both the visual and the auditory stimuli. At the beginning of each trial, the fixation stimulus was presented for 600~800 ms in the center of the monitor. Following the fixation stimulus, the cue was presented for 200 ms, which could predict (50% or 80%) the location of the target. Before the target that appeared for 100 ms, the inter stimulus interval (ISI) lasted for 700 ms. The target (A, V, or AV) randomly appeared for 100 ms in the left or right locations. At last, the fixation stimuli appeared for 600 ms to wait for the correspondence responses to targets. During the experiment, the participants were asked to locate targets by pressing buttons (F/J) as quickly and accurately as possible. The results showed that the responses to AV targets were faster than V or A targets, indicating the appearance of the bimodal advancement effect in both experiments. Each target modality showed significant cueing effect. And the cueing effect in experiment 2 was significantly larger than the cueing effect in experiment 1. In addition, in experiment 1, relative multisensory response enhancement (rMRE), race model (probability difference) showed no significant difference at valid compared to invalid locations. However, in experiment 2, rMRE and race model (probability difference) increased at valid compared to invalid locations. The results suggested that endogenous spatial attention enhanced audiovisual integration in high spatial validity condition. In summary, Endogenous spatial attention had different effects on the audiovisual integration under different spatial cue validity. High spatial cue validity enhanced audiovisual integration. The current study provides direct behavioral evidence for endogenous spatial attention to enhance audiovisual integration.
Subjects: Astronomy >> Astrophysical processes submitted time 2019-04-03 Cooperative journals: 《天文研究与技术》
Abstract： 在全球导航卫星系统（Global Navigation Satellite System，GNSS）中，定位精度是一个重要的性能指标；准确的定位误差模型有利于理解系统的工作模式，同时也为进一步提高系统性能提供指导。当卫星的测距误差满足相互独立和方差均一的条件时，定位误差等于测距误差标准差乘以几何精度因子。然而实际应用中，由于不同卫星信号的传播路径的不同，测距误差的统计特征难以相同。尤其当有卫星信号受到多径干扰与电离层闪烁影响时，不同卫星间的测距误差会有显著的差异。本文介绍了一种利用奇异值分解方法建立的非均一测距误差的定位误差理论模型；利用北京站与香港站的实测数据，对受到多径效应与电离层闪烁影响的定位误差进行分析。结果表明其统计特性与非均一方差的定位误差模型给出的结果一致，验证了模型的正确性和有效性。
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