Identifying tourist-functional relations of urban places through Foursquare from Barcelona

This is a post-peer-review, pre-copyedit version of an article published in GEOJOURNAL. The final authenticated version is available online at: http://dx.doi.org/10.1007/s10708-019-10055-9Previous research has mainly focused on spatial relations among tourist attractions in urban areas. However, few studies have examined the functional relations between tourist attractions and other urban places (i.e. the flows of tourists between them). Therefore, this study focuses on quantification of the tourist-functional relations among Places of Interest (POIs) using Foursquare data from Barcelona. This represents an effort to highlight the important functional closeness between different types of POIs whose significance is not usually obvious from their spatial relationships. In order to quantify these functional relationships, this paper classifies Foursquare POIs into 22 categories according to their different usages and constructs a matrix of usage-flows to depict the connections among these different usages. A model of interaction values is introduced to describe the strength of relations and identify the dominant tourist usages. The results confirm that the functional centroids differ from these spatial distributions which only focused around tourist attractions. In addition to tourist attractions, places in the categories of Restaurants, Transport, and Hotels play important roles in functional relationship of tourism. The typical urban usages of tourists can be distinguished by the interaction values between these categories. Our model provides a practical method to quantify the interlinkage of usages of POIs based on tourist flows. In particular, LBSN data has potential as a method to observe the tourist-functional relations among places.Peer ReviewedPostprint (author's final draft

Registration Combining Wide and Narrow Baseline Feature Tracking Techniques for Markerless AR Systems

Augmented reality (AR) is a field of computer research which deals with the combination of real world and computer generated data. Registration is one of the most difficult problems currently limiting the usability of AR systems. In this paper, we propose a novel natural feature tracking based registration method for AR applications. The proposed method has following advantages: (1) it is simple and efficient, as no man-made markers are needed for both indoor and outdoor AR applications; moreover, it can work with arbitrary geometric shapes including planar, near planar and non planar structures which really enhance the usability of AR systems. (2) Thanks to the reduced SIFT based augmented optical flow tracker, the virtual scene can still be augmented on the specified areas even under the circumstances of occlusion and large changes in viewpoint during the entire process. (3) It is easy to use, because the adaptive classification tree based matching strategy can give us fast and accurate initialization, even when the initial camera is different from the reference image to a large degree. Experimental evaluations validate the performance of the proposed method for online pose tracking and augmentation

Dynamic Behaviors of a Discrete Periodic Predator-Prey-Mutualist System

A nonautonomous discrete predator-prey-mutualist system is proposed and studied in this paper. Sufficient conditions which ensure the permanence and existence of a unique globally stable periodic solution are obtained. We also investigate the extinction property of the predator species; our results indicate that if the cooperative effect between the prey and mutualist species is large enough, then the predator species will be driven to extinction due to the lack of enough food. Two examples together with numerical simulations show the feasibility of the main results

Quantifying the relationship between public sentiment and urban environment in Barcelona

Public sentiment provides an important social reference for urban management and planning. The relationship between public sentiment and a single type of land use has yielded stable results in previous studies. Hitherto, there has been relatively little research on the correlation of the entire urban environment with public sentiment. Based on the unit of statistical area in Barcelona city, this research uses Twitter sentiment to represent public sentiment and develops a regression model for understanding the interrelationship of four layers: sociodemographic, built-environment, human mobility and socioeconomic activities. The result shows that: 1) The long-term spatial difference in public sentiment has correlations with the urban environment, though it is not decisive. 2) Regardless of disruptive events that are directly associated with public sentiments, the wealthier areas show a more positive correlation with higher public sentiment. 3) The distribution of sentiment tweets (non-neutral) has a close relationship with places where there is a high flow of human activities. This study contributes to the systematic literature of urban applications of sentiment analysis with new empirical observations and a transferable methodology

An efficient Gehan-type estimation for the accelerated failure time model with clustered and censored data

In medical studies, the collected covariates usually contain underlying outliers. For clustered /longitudinal data with censored observations, the traditional Gehan-type estimator is robust to outliers existing in response but sensitive to outliers in the covariate domain, and it also ignores the within-cluster correlations. To take account of within-cluster correlations, varying cluster sizes, and outliers in covariates, we propose weighted Gehan-type estimating functions for parameter estimation in the accelerated failure time model for clustered data. We provide the asymptotic properties of the resulting estimators and carry out simulation studies to evaluate the performance of the proposed method under a variety of realistic settings. The simulation results demonstrate that the proposed method is robust to the outliers existing in the covariate domain and lead to much more efficient estimators when a strong within-cluster correlation exists. Finally, the proposed method is applied to a medical dataset and more reliable and convincing results are hence obtained.Comment: ready for submissio

A new evaluation of the role of urbanization to warming at various spatial scales: Evidence from the Guangdong‐Hong Kong‐Macao Region, China

The urbanization impacts on Surface Air Temperature (SAT) change in the Guangdong‐Hong Kong‐Macao region (GHMR) from 1979 to 2018 are examined using homogeneous surface observations, reanalysis, and remote sensing. Results show that the warming due to urbanization tends to be smaller or insignificant as the spatial scale increases. The urbanization contribution to the local warming can reach as high as 50% in the center of each metropolis, remains high (~25%) in the Greater Bay Area (GBA), and decreases to about 10% in the whole GHMR. The warming in GHMR is nearly uniform throughout the day, and therefore the observed trend of the Diurnal Temperature Range (DTR) is not statistically significant. However, the urbanization contribution exhibits distinct seasonal variations, large in summer and autumn while smaller in winter and spring

Effects of a novel recombinant somatostatin DNA vaccination on rat fertility and offspring growth

In this study, we investigated the immune effects of a novel somatostatin (SS) DNA vaccine—pVAX- asd-GS/2SS (pGS/2SS), administrated with intramuscular (IM) and subcutaneous (SC) two delivery routes on female rat fertility and offspring growth. Results show that this pGS/2SS DNA vaccine could induce effective  anti-SS immune response in rats (IM group and SC group). The antibody peak of female rats in IM group  occurred later than that in SC group (12th week vs. 10th week), but higher than that in SC group  (OD=1.122±0.273 vs. OD=0.614±0.183). Immunized groups had higher pregnancy rate, litter size, birth  weight of pup and weight gain of pup than the control group (P<0.05). Compared to SC immunization, IM  immunization had better improvement in the pregnancy rate of dam and the weight gain of pup (P<0.05).  However, in litter sizes and birth weight of pups, SC immunization was better than IM immunization. In  conclusion, pGS/2SS as a powerful DNA vaccine improves the fertility of female rats and the growth of pups.Key words: Somatostatin, DNA vaccine, rat, fertility, pup growth