Search

In space optical applications, the piezoelectric-actuated fast steering mirror (FSM) is one of the pivotal components for high-precision beam capturing and trajectory tracking. The FSM is restrained in small-angle scanning applications due to the short actuation stroke of the incorporated piezoelectric materials. This study introduces a dual-axis sub-radian stroke FSM with a high ratio of output range to resolution and self-sensing capability, based on cascading structures for displacement amplification and flexible parts for feedback. Theoretical analyses and finite element analysis (FEA) are applied to elucidate the driving and deformation mechanisms of the proposed FSM structure. To ensure the performance of the proposed FSM, the double-loop control strategies are implemented independently for rotation around the two orthogonal axes. Experimental results reveal that both axes can rotate 148.67 mrad under the closed-loop control, with the ratio of output range to resolution larger than 3.90 × 104, superior to existing FSMs. We further demonstrate with designed experiments of tracking complex trajectories that the relative tracking accuracy error remains lower than 0.02%. [ABSTRACT FROM AUTHOR]

Drawing upon psychological contract theory, this study investigated how and when perceived overqualification may affect employees' creativity. Data were collected from 164 employees and their immediate supervisors in Chinese manufacturing, information technology (IT), and services companies (female = 53.05%; age range 31–50 years; bachelor's degree = 70.73%) using a two-wave approach over one month. Results from hierarchical regression analysis and bootstrapping analysis indicated that self-perception of overqualification was associated with lower employee creativity via less job crafting. Furthermore, higher leader–member exchange accentuated the indirect effect of perceived overqualification on creativity via job crafting. These findings are consistent with psychological contract theory in that overqualified employees are aware of organisations' failure to live up to the psychological contract. These findings imply a need for addressing organisational context factors to provide guidance for supporting employee job crafting across qualification levels. [ABSTRACT FROM AUTHOR]

The paper considers an online scheduling problem with the effects of both learning and deterioration to minimize the total completion time. More specifically, we assume that the actual processing length of job Jj is p jr = p j r b + at , where pj is the initial processing time of Jj, t is the starting time of Jj, r is the seating arrangement position of Jj, b is the learning factor and a is the deterioration factor, respectively. For this problem, we show that the performance ratio of any deterministic online algorithm is not <2 and provide a best possible online algorithm DSBPT with a competitive ratio of 2. Furthermore, we also present a concise computational simulation study to verify the effectiveness and efficiency of the proposed algorithm DSBPT, as well as the management implications provided for decision-makers to production optimization. [ABSTRACT FROM AUTHOR]

Aim: This study aims to investigate α‐fetoprotein (AFP) trajectories for prediction of survival outcomes after hepatic arterial infusion chemotherapy (HAIC) treatment in large hepatocellular carcinoma (HCC). Methods: From May 2014 to June 2020, 889 eligible patients with large HCC underwent HAIC were retrospectively enrolled from five hospitals. A latent class growth mixed (LCGM) model was applied to distinguish potential AFP level dynamic changing trajectories. Inverse‐probability‐of‐treatment weighted (IPTW) analyses were performed to eliminate unmeasured confounders through marginal structural models. Multivariate Cox proportional hazard regression analyses were used to determine the overall survival (OS) in patients with large HCC. Performance of these serum markers for survival prediction was compared by areas under receiver operating characteristic analysis with the Delong test. Results: The median follow‐up time was 23.7 (interquartile range, 3.8–115.3). A total of 1009 patients with large HCC, who underwent HAIC with AFP repeatedly measured 3–10 times, were enrolled in the study. Three distinct trajectories of these serum AFP were identified using the LCGM model: high stable (37.0%; n = 373), low stable (15.7%; n = 159), and sharp‐falling (47.3%; n = 477). Multivariate Cox proportional hazard regression analyses found that ALBI stage 2–3, BCLC‐C stage and high‐stable AFP trajectories were associated with OS. AFP trajectories yield the optimal predictive performance in all risk factors. Conclusions: The AFP trajectories based on longitudinal AFP change showed outstanding performance for predicting survival outcomes after HAIC treatment in large HCC, which provide a potential monitoring tool for improving clinical decision‐making. [ABSTRACT FROM AUTHOR]

The setting we consider is nonpreemptive single machine online scheduling, with the objective to minimize the maximum weighted completion time of jobs. The weight of the job is not only limited strictly within the processing time compass of this job, but also agreeable with processing time of this job, i.e., apj ≤ wj ≤ bpj (a ≥ √5-1/2b, b b ≥ a) and if wi > wj, then pi ≥ pj. Especially, if wi = wj, then pi = pj. Significantly, there are irrelevant jobs arriving online over time and the knowledge of each job Jj, such as its processing length pj and weight wj, is not revealed for the scheduler until it is released at time rj. By means of adversary method, it is explicitly derived that the lower bound of the considered problem is 1 + b/b+a. Then we provide a best possible online algorithm with the competitive ratio of 1 + b/b+a. Moreover, the competitive ratio of this algorithm is √5+1/2 when a = √5-1/2 b. [ABSTRACT FROM AUTHOR]