Encoding-specificity instead of online integration of real-world spatial regularities for objects in working memory

In daily life scenarios, most objects are not independent of each other; rather, they show a high degree of spatial regularity (e.g., beach umbrellas appear above beach chairs, not under them). Previous studies have shown a benefit of spatial regularities in visual working memory (VWM) performance of real-world objects, termed the spatial regularity effect. However, the mechanisms underlying this effect remain unclear. The spatial regularity effect can be explained by an “encoding-specificity” hypothesis or a “perception-alike” hypothesis. The former suggests that spatial regularity will enhance the visual encoding process but will not operate in information integration during VWM maintenance, while the latter suggests that spatial regularity will play a role in both the visual encoding and VWM maintenance processes. We tested these two hypotheses by investigating whether VWM integrates sequentially presented real-world objects by focusing on the existence of the spatial regularity effect. In Experiment 1, we manipulated the presentation (simultaneous vs. sequential) and regularity (with vs. without regularity) of memory arrays among pairs of real-world objects. The spatial regularity of memory objects improved the VWM performance in simultaneous presentation trials, but not in sequential presentation trials. In Experiment 2, we examined whether overburdened memory load hindered the spatial regularity effect in sequential presentation trials. We again found an absence of the spatial regularity effect, regardless of the memory load. These results suggest that participants were unable to integrate real-world objects into pairs based on spatial regularity during the VWM maintenance process. Therefore, the present results support the “encoding-specificity” hypothesis, implying that although the spatial regularity of real-world objects can enhance the efficiency of the encoding process in VWM, VWM cannot exploit spatial regularity to help organize sampled sequential information into meaningful groups.

Irregular distribution of grid cell firing fields in rats exploring a 3D volumetric space

We investigated how entorhinal grid cells encode volumetric space. On a horizontal surface, grid cells usually produce multiple, spatially focal, approximately circular firing fields that are evenly sized and spaced to form a regular, close-packed, hexagonal array. This spatial regularity has been suggested to underlie navigational computations. In three dimensions, theoretically the equivalent firing pattern would be a regular, hexagonal close packing of evenly sized spherical fields. In the present study, we report that, in rats foraging in a cubic lattice, grid cells maintained normal temporal firing characteristics and produced spatially stable firing fields. However, although most grid fields were ellipsoid, they were sparser, larger, more variably sized and irregularly arranged, even when only fields abutting the lower surface (equivalent to the floor) were considered. Thus, grid self-organization is shaped by the environment’s structure and/or movement affordances, and grids may not need to be regular to support spatial computations.

Functional Assessment and Coordination Characteristics of Production, Living, Ecological Function—A Case Study of Henan Province, China

Multifunctional state assessment was the basis of time sequence design of territory spatial development and overall utilisation. This study aimed to identify the ecological-production-living (PLE) territory spatial function to provide a basis for territory spatial planning. It took Henan Province as the research area. This study developed a methodology to assess differentiation characteristics for PLE function, a method that integrates functional merging and geographic information technology. We used the coordination degree model and spatial autocorrelation analysis to reveal the coordination of spatial functions of the province. The results were as follows: (1) During the study period, the land production function of main grain-producing areas decreased slowly, and production and living function values of the Central Plains urban agglomeration with Zhengzhou as the centre were in an upward trend. The characteristics of urban-rural dualization were prominent, and ecological function value decreased year by year. (2) The laws of territorial spatial functions had different manifestations in different stages (1990–2005 and 2005–2018). By different characteristic laws, the change in production function in the later period was bigger than that in the previous period. The living function maintained a good continuity expansion characteristic before and after. The spatial regularity distribution characteristics of ecological function were weak, and the overall environment became worse than before. (3) The territory space of middle and low coordination function types was the most important type, and the aggregation was relatively weak. Xuchang County and Weihui City showed better states of functional coordination aggregation. Lushi County, Xinxian County, and Shangcheng County, which were in the western and southern mountainous and hilly areas, showed low-low aggregation characteristics. Thus, the government will strengthen targeted control over territorial space. This study provides a reference for the overall deployment of the development and utilisation of territory space in Henan Province.

Regularity of Local Times Associated with Volterra–Lévy Processes and Path-Wise Regularization of Stochastic Differential Equations

We investigate the space-time regularity of the local time associated with Volterra–Lévy processes, including Volterra processes driven by $$\alpha $$ α -stable processes for $$\alpha \in (0,2]$$ α ∈ ( 0 , 2 ] . We show that the spatial regularity of the local time for Volterra–Lévy process is $${\mathbb {P}}$$ P -a.s. inverse proportional to the singularity of the associated Volterra kernel. We apply our results to the investigation of path-wise regularizing effects obtained by perturbation of ordinary differential equations by a Volterra–Lévy process which has sufficiently regular local time. Following along the lines of Harang and Perkowski (2020), we show existence, uniqueness and differentiability of the flow associated with such equations.

Spatial regularity of the young stellar population in the ring of NGC 6217

The relative contribution of various physical processes to the spatial and temporal distribution of molecular clouds and star-forming regions in the disks of galaxies has not yet been the subject of extensive study. Investigating the spatial regularity in the distribution of the young stellar population in spiral and ring structures is a good test for studying this contribution. In this paper, we look at the photometric properties of the ring and spiral arms in the barred spiral galaxy NGC 6217 based on an analysis using GALEX ultraviolet, optical UBVRI, and Hα surface photometry data. The ring in the galaxy is located near the corotation area. We found evidence of spatial regularity in the distribution of the young stellar population along the galaxy ring. The characteristic scale of spacing is about 700 pc. At the same time, we did not find a similar regularity in the distribution of the young stellar population along the spiral arms of NGC 6217. The spatial regularity in the concentration of young stellar groupings along spiral arms is a quite rare phenomenon and it has never previously been seen in galactic rings.

Analysis of the mountain sickness of tourists in China from 2015-2017

Background: Mountain sickness significantly affects tourists who travel in plateau areas. Most studies have researched patients, climbers and local residents to analyse the identification, causes, symptoms and effects of mountain sickness, and only a few have assessed tourists.Methods: This study used the Jiangtai Insurance Broker, an exemplary underwriting platform for travel agency liability insurance in China, as the data acquisition platform to analyse tourist altitude sickness from an epidemiological perspective. The chi-square test was used to test the distribution of mountain sickness diseases and symptoms among different genders and ages. A geographic information system (GIS) was used to generate a spatial distribution map of tourist mountain sickness.Results: From 2015 to 2017, there were 361 cases of tourist mountain sickness, which were distributed in 4 altitudinal classes. The incidence of mountain sickness was higher in women than in men. Tourists aged 40-69 years were the main group of patients. Acute mountain sickness (AMS) and high-altitude pulmonary edema (HAPE) were the main high-altitude diseases and mainly occurred in the 2nd and 3rd class altitude regions. Hypoxia, dizziness, headache and chest tightness were the main symptoms of mountain sickness. Spring, summer and autumn were the peak seasons for the onset of mountain sickness. Mountain sickness cases were concentrated in a few cities in Western China.Conclusion: This study analysed the genders and characteristics of the main tourist population that suffered from mountain sickness and investigated the diseases and the temporal and spatial regularity of disease from an epidemiological perspective. The research showed that the onset of mountain sickness was related to the individual physique and age of tourists, speed of entering the plateau, season and altitude. This study is significant as a reference for the risk assessment of tourists visiting plateau areas.

Location Prediction over Sparse User Mobility Traces Using RNNs: Flashback in Hidden States!

Location prediction is a key problem in human mobility modeling, which predicts a user's next location based on historical user mobility traces. As a sequential prediction problem by nature, it has been recently studied using Recurrent Neural Networks (RNNs). Due to the sparsity of user mobility traces, existing techniques strive to improve RNNs by considering spatiotemporal contexts. The most adopted scheme is to incorporate spatiotemporal factors into the recurrent hidden state passing process of RNNs using context-parameterized transition matrices or gates. However, such a scheme oversimplifies the temporal periodicity and spatial regularity of user mobility, and thus cannot fully benefit from rich historical spatiotemporal contexts encoded in user mobility traces. Against this background, we propose Flashback, a general RNN architecture designed for modeling sparse user mobility traces by doing flashbacks on hidden states in RNNs. Specifically, Flashback explicitly uses spatiotemporal contexts to search past hidden states with high predictive power (i.e., historical hidden states sharing similar contexts as the current one) for location prediction, which can then directly benefit from rich spatiotemporal contexts. Our extensive evaluation compares Flashback against a sizable collection of state-of-the-art techniques on two real-world LBSN datasets. Results show that Flashback consistently and significantly outperforms state-of-the-art RNNs involving spatiotemporal factors by 15.9% to 27.6% in the next location prediction task.

Comprehensive Spatio-Temporal Analysis of Travel Climate Comfort Degree and Rainstorm-Flood Disaster Risk in the China–Russia Border Region

Infrastructure and tourism is gradually increasing along the China–Russia border with the development of the China–Mongolia–Russia economic corridor. Facing the issues of thermal comfort and rainstorm-flood risk in the neighborhood area between China and Russia, we constructed homologous evaluation models to analyze spatial regularity and internal variations of their effect. Among the results, approximately 55% of the area was classified into the categories of “comfort” and “high comfort” in summer. Oppositely, the situation of most areas in winter corresponds to physical discomfort. On the other hand, the high-risk area of rainstorm-flood in spring and summer is principally located in the northern and southern regions, respectively, while this is further expanded in autumn. After that, the risk level turns to medium and low. Subsequently, a comprehensive assessment coordinate system of the two results was constructed to identify the distribution pattern of a seasonal suitable area for traveling in binary ways. The evaluation shows that Great Khingan Range in the north-western Heilongjiang province is the preferable place among most of seasons, especially in summer. While on the Russian side, the corresponding area is mainly spread over its southern coastal cities. The study is expected to provide recommendations for reasonable year-round travel time, space selection, and risk decision support for millions of people traveling between China and Russia.

The Influence of Typography on Algorithms that Predict the Speed and Comfort of Reading

1. The speed with which text can be read is determined in part by the spatial regularity and similarity of vertical letter strokes as assessed by the height of the first peak in the horizontal autocorrelation of the text. The height of this peak was determined for two passages in 20 fonts. The peak was unaffected by the size of the text or its content but was influenced by the font design. Sans serif fonts usually had a lower peak than serif fonts because the presence of serifs usually (but not invariably) resulted in a more even spacing of letter strokes. There were small effects of justification and font-dependent effects of font expansion and compression. 2. The visual comfort of images can be estimated from the extent to which the Fourier amplitude spectrum conforms to 1/f. Students were asked to adjust iBooks to obtain their preferred settings of font and layout. The preference was predicted by the extent to which the Fourier amplitude spectrum approximated 1/f, which in turn was jointly affected by the design of the font, its weight and the ratio of x-height to line separation. Two algorithms based on the autocorrelation and Fourier transformation of text can be usefully applied to any orthography to estimate likely speed and comfort of reading.

Well-posedness for nonlinear SPDEs with strongly continuous perturbation

We consider the well-posedness of a stochastic evolution problem in a bounded Lipschitz domain D ⊂ ℝ d with homogeneous Dirichlet boundary conditions and an initial condition in L2(D). The main technical difficulties in proving the result of existence and uniqueness of a solution arise from the nonlinear diffusion-convection operator in divergence form which is given by the sum of a Carathéodory function satisfying p-type growth associated with coercivity assumptions and a Lipschitz continuous perturbation. In particular, we consider the case 1 < p < 2 with an appropriate lower bound on p determined by the space dimension. Another difficulty arises from the fact that the additive stochastic perturbation with values in L2(D) on the right-hand side of the equation does not inherit the Sobolev spatial regularity from the solution as in the multiplicative noise case.