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Researchers proposed several data-driven methods to efficiently guess user-chosen passwords for password strength metering or password recovery in the past decades. However, these methods are usually evaluated under ad hoc scenarios with limited data sets. Thus, this motivates us to conduct a systematic and comparative investigation with a very large-scale data corpus for such state-of-the-art cracking methods. In this paper, we present the large-scale empirical study on password-cracking methods proposed by the academic community since 2005, leveraging about 220 million plaintext passwords leaked from 12 popular websites during the past decade. Specifically, we conduct our empirical evaluation in two cracking scenarios, i.e., cracking under extensive-knowledge and limited-knowledge. The evaluation concludes that no cracking method may outperform others from all aspects in these offline scenarios. The actual cracking performance is determined by multiple factors, including the underlying model principle along with dataset attributes such as length and structure characteristics. Then, we perform further evaluation by analyzing the set of cracked passwords in each targeting dataset. We get some interesting observations that make sense of many cracking behaviors and come up with some suggestions on how to choose a more effective password-cracking method under these two offline cracking scenarios.

Background Emergency department (ED) visits associated with prescription opioids have increased in the last ten years. This study describes the opioid utilization of patients discharged from the ED with an opioid prescription for pain, 14 to 21 days post discharge. Methods This is a prospective, single-centered, survey-based observational descriptive study conducted from December 2017 to February 2018 in the ED at a tertiary level 1 trauma center. The primary outcomes were the percentage of patients with unused opioids and the quantity of opioids remaining 14 to 21 days post ED discharge. A sample of ED patients who received an oral opioid prescription were approached for informed consent and received a telephone survey 14 to 21 days post discharge. Results Of 178 patients approached for consent, 122 were enrolled. Among them, 98 were successfully surveyed (80.3%). The median number of pills prescribed was 8 (IQR:8–12). Nearly half (49%) of patients had unused opioids 14 to 21 days post ED discharge, not including 9.2% of patients who never filled their prescriptions. Of the total 980 pills prescribed, 327 pills remained unused (33.4%). Only 55.1% of patients reported receiving counseling on side effect of opioids and 21.4% of patients reported they received counseling on storage and disposal. Conclusion The majority of patients in this study had unused or unfilled opioids 14 to 21 days post ED discharge, and approximately one third of the opioids prescribed remained unused. Most patients did not recall receiving opioid related education including proper disposal of medication.

Developing integrable, nanoscale, and low-energy-consumption lasers is a crucial step toward on-chip optical communications and computing technologies. The strong exciton-photon interaction that emerged in monolayer transition metal dichalcogenides (TMDs) holds promise for engineering and integration. Herein, we prepare the MoSe2/microsphere cavities excitonic lasers by placing SiO2 microspheres on top of a monolayer MoSe2 film. By virtue of continuous-wave exciting MoSe2/microsphere whispering gallery mode (WGM) cavities, we realize multiple excitonic WGM lasing in the emission wavelength range of ∼750-875 nm at room temperature with tunable properties of free spectral range (FSR) and full width at half-maximum (fwhm) by varying the microsphere size. Theoretical calculations based on the finite element method (FEM) using COMSOL software were utilized to identify lasing modes and reveal the corresponding electric field distribution. These findings help to deepen fundamental understanding of excitonic WGM lasing and provide a promising research platform for integrable, scalable, and low-cost laser devices.

With the rapid development of the economy, , bridge construction, as one of the elements of modern traffic engineering often becomes the key part which restricts the whole construction. The external pre-stressing technique of precast segmental construction gets more and more attention in modern bridge construction because of its unique advantage. However, as a special structure of precast segmental construction, the joint’s strength and connection reliability is closely related to stress and service performance of the pre-spliced structure. So it is necessary to analyze the structure and mechanical properties of the joint. For the research of the joint in precast segmental construction applied in externally pre-stressed concrete bridges, this paper introduces the types and characteristics of joint structure, and uses the similar sectional analysis method of internal pre-stressing structure to analyze the bending performance and shear performance in a cross-section of a joint. At the same time, on the basis of the consideration of the secondary effect of external pre-stressing, some kinds of common calculation formulas used for bearing capacity calculation in the cross-section of the joints are given. Finally, results of numerical simulation analysis by the finite element program ANSYS and some experimental study from both at home and abroad prove the rationality of these formulas.