We report the results of a comparative study of drawings completed by 952 children aged between 6-13 years in the UK and Chinese ordinary schools. Although there was no significant difference in standard between the drawings of these two cultural groups the drawings of 240 children who attended a week-end art school in Beijing were given consistently higher ratings. In addition, there were noticeable differences in style, composition, colour and depth cues among all three samples.

The electrochemical aptamer‐based (E‐AB) biosensor usually has a long reaction time when detecting thrombin. This work reports the design of an E‐AB biosensor with dual recognition sites to quickly detect thrombin. Specifically, two specific recognition sites of thrombin were used to design three aptamer sequences (TBA‐15, TBA‐29 and TBA‐U), followed by fabrication of corresponding sensors. First, we tested these three types of biosensors in tris buffer solution, and found that the response time of the TBA‐U sensor to the same concentration of thrombin was about 2 hours, which is shorter than TBA‐15 and TBA‐29 sensors. Then, we also did the same test in 50 % diluted serum with 500 nM thrombin. The response time of the TBA‐U sensor was about 2 hours, which is still faster than the 3 hours of TBA‐15 sensor and the 5.5 hours for TBA‐29 sensor. In addition, in terms of dynamic range and specificity, TBA‐U has good performance.

Wi-Fi fingerprinting has been widely used for indoor localization because of its good cost-effectiveness. However, it suffers from relatively low localization accuracy and robustness owing to the signal fluctuations. Virtual Access Points (VAP) can effectively reduce the impact of signal fluctuation problem in Wi-Fi fingerprinting. Current techniques normally use the Log-Normal Shadowing Model to estimate the virtual location of the access point. This would lead to inaccurate location estimation due to the signal attenuation factor in the model, which is difficult to be determined. To overcome this challenge, in this study, we propose a novel approach to calculating the virtual location of the access points by using the Apollonius Circle theory, specifically the distance ratio, which can eliminate the attenuation parameter term in the original model. This is based on the assumption that neighboring locations share the same attenuation parameter corresponding to the signal attenuation caused by obstacles. We evaluated the proposed method in a laboratory building with three different kinds of scenes and 1194 test points in total. The experimental results show that the proposed approach can improve the accuracy and robustness of the Wi-Fi fingerprinting techniques and achieve state-of-art performance.

Electrochemical aptamer-based (E-AB) sensors suffer from sensor-to-sensor signal variations due to the variation in the total number of probes immobilized on the sensor surface, the effective working area, and the heterogeneity properties of the electrode surface, thus requiring a calibration step prior to each measurement. This is impractical, if not possible, for some cases, e.g., in a complex matrix including blood samples.In response, we propose a calibration-free approach to achieve the measurement of biorelevant small-molecule and protein analytes. Specifically, we employed one reporter labeled onto an aptamer (e.g., methylene blue) for redox signaling, and the other reporter (e.g., ferrocene) was modified onto a self-assembly monolayer as a reference signal. By taking the ratio of the two signals, we achieved a much improved baseline stability and sensor-to-sensor reproducibility, which allows the calibration-free measurement of the analysis of the respective targets, including doxorubicin, vancomycin, and thrombin in both simple buffer and even directly complex samples including serum and whole blood.

Map-matching is a popular method that uses spatial information to improve the accuracy of positioning methods. The performance of map matching methods is closely related to spatial characteristics. Although several studies have demonstrated that certain map matching algorithms are affected by some spatial structures (e.g., parallel paths), they focus on the analysis of single map matching method or few spatial structures. In this study, we explored how the most commonly-used four spatial characteristics (namely forks, open spaces, corners, and narrow corridors) affect three popular map matching methods, namely particle filtering (PF), hidden Markov model (HMM), and geometric methods. We first provide a theoretical analysis on how spatial characteristics affect the performance of map matching methods, and then evaluate these effects through experiments. We found that corners and narrow corridors are helpful in improving the positioning accuracy, while forks and open spaces often lead to a larger positioning error. We hope that our findings are helpful for future researchers in choosing proper map matching algorithms with considering the spatial characteristics.