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Mining spatiotemporal mobility patterns is crucial for optimizing urban planning, enhancing transportation systems, and improving public safety by providing useful insights into human movement and behavior over space and time. As an unsupervised learning technique, time series clustering has gained considerable attention due to its efficiency. However, the existing literature has often overlooked the inherent characteristics of mobility data, including high-dimensionality, noise, outliers, and time distortions. This oversight can lead to potentially large computational costs and inaccurate patterns. To address these challenges, this paper proposes a novel neural network-based method integrating temporal autoencoder and dynamic time warping-based K-means clustering algorithm to mutually promote each other for mining spatiotemporal mobility patterns. Comparative results showed that our proposed method outperformed several time series clustering techniques in accurately identifying mobility patterns on both synthetic and real-world data, which provides a reliable foundation for data-driven decision-making. Furthermore, we applied the method to monthly county-level mobility data during the COVID-19 pandemic in the U.S., revealing significant differences in mobility changes between rural and urban areas, as well as the impact of public response and health considerations on mobility patterns. 

Rust is a young systems programming language designed to provide both the safety guarantees of high-level languages and the execution performance of low-level languages. To achieve this design goal, Rust provides a suite of safety rules and checks against those rules at the compile time to eliminate many memory-safety and thread-safety issues. Due to its safety and performance, Rust’s popularity has increased significantly in recent years, and it has already been adopted to build many safety-critical software systems. It is critical to understand the learning and programming challenges imposed by Rust’s safety rules. For this purpose, we first conducted an empirical study through close, manual inspection of 100 Rust-related Stack Overflow questions. We sought to understand (1) what safety rules are challenging to learn and program with, (2) under which contexts a safety rule becomes more difficult to apply, and (3) whether the Rust compiler is sufficiently helpful in debugging safety-rule violations. We then performed an online survey with 101 Rust programmers to validate the findings of the empirical study. We invited participants to evaluate program variants that differ from each other, either in terms of violated safety rules or the code constructs involved in the violation, and compared the participants’ performance on the variants. Our mixed-methods investigation revealed a range of consistent findings that can benefit Rust learners, practitioners, and language designers. 

Glycine, the simplest amino acid, is considered a promising functional biomaterial owing to its excellent biocompatibility and strong out-of-plane piezoelectricity. Practical applications require glycine films to be manufactured with their strong piezoelectric polar 〈001〉 direction aligned with the film thickness. Based on the recently-developed solidification approach of a polyvinyl alcohol (PVA) and glycine aqueous solution, in this work, we demonstrate that the crystal orientation of the as-synthesized film is determined by the orientation of glycine crystal nuclei. By controlling the local nucleation kinetics via surface curvature tuning, we shifted the nucleation site from the edge to the middle of the liquid film, and thereby aligned the 〈001〉 direction vertically. As a result, the PVA–glycine–PVA sandwich film exhibits the highest aver-age piezoelectric coefficient d 33 of 6.13 ± 1.13 pC N −1 . This work demonstrates a promising kinetic approach to achieve crystallization and property control in a scalable biocrystal manufacturing process. 

Different techniques have been recommended to detect fraudulent responses in online surveys, but little research has been taken to systematically test the extent to which they actually work in practice. In this paper, we conduct an empirical evaluation of 22 antifraud tests in two complementary online surveys. The first survey recruits Rust programmers on public online forums and social media networks. We find that fraudulent respondents involve both bot and human characteristics. Among different anti-fraud tests, those designed based on domain knowledge are the most effective. By combining individual tests, we can achieve a detection performance as good as commercial techniques while making the results more explainable. To explore these tests under a broader context, we ran a different survey on Amazon Mechanical Turk (MTurk). The results show that for a generic survey without requiring users to have any domain knowledge, it is more difficult to distinguish fraudulent responses. However, a subset of tests still remain effective.