No abstract

Differential item functioning (DIF) occurs when the probability of endorsing an item differs across groups for individuals with the same latent trait level. The presence of DIF items may jeopardize the validity of an instrument; therefore, it is crucial to identify DIF items in routine operations of educational assessment. While DIF detection procedures based on item response theory (IRT) have been widely used, a majority of IRT-based DIF tests assume predefined anchor (i.e., DIF-free) items. Not only is this assumption strong, but violations to it may also lead to erroneous inferences, for example, an inflated Type I error rate. We propose a general framework to define the effect sizes of DIF without a priori knowledge of anchor items. In particular, we quantify DIF by item-specific residuals from a regression model fitted to the true item parameters in respective groups. Moreover, the null distribution of the proposed test statistic using robust estimator can be derived analytically or approximated numerically even when there is a mix of DIF and non-DIF items, which yields asymptotically justified statistical inference. The Type I error rate and the power performance of the proposed procedure are evaluated and compared with the conventional likelihood-ratio DIF tests in a Monte Carlo experiment. Our simulation study has shown promising results in controlling Type I error rate and power of detecting DIF items. Even when there is a mix of DIF and non-DIF items, the true and false alarm rate can be well controlled when a robust regression estimator is used.

This study centered on emergent bilingual (EB) students with specific reading comprehension deficits (S-RCD), that is, with poor reading comprehension despite solid word identification skills. The participants were 209 students in Grades 2 to 4, including both EBs and English Monolinguals (EMs) with and without S-RCD. Mean comparisons indicated that EBs and EMs with S-RCD showed weaknesses relative to typically developing (TD) readers in oral language, word identification, inference making, and reading engagement, but not in executive functioning. Longitudinal analyses indicated that across two academic years S-RCD persisted for 41% of EBs and EMs alike. Altogether, the study extends research on EBs with S-RCD by identifying variables beyond oral language that may account for their reading comprehension difficulties and providing insight into the extent to which their reading comprehension and word identification performance levels evolve during elementary school. Furthermore, the findings point to the importance of early identification and intervention for weaknesses in reading comprehension and its component elements in both EBs and EMS.

No abstract

No abstract

Socioemotional constructs have been receiving increased attention as contributors to individuals’ literacy development. However, in comparison with positive socioemotional constructs, negative socioemotional constructs have been understudied with respect to their role in reading achievement in both emergent bilinguals (EBs) and English monolinguals (EMs). In the present study, we addressed this gap by examining reading anxiety in 339 EBs, who primarily spoke Spanish as their first language, and 178 EMs in grades 3–5, using a latent variable approach. We used structural equation modeling to form latent variables for reading anxiety, reading engagement, and reading achievement; compare latent variable means for EBs and EMs; and examine relations among the three focal constructs across the two language groups. The EBs and EMs showed similar levels of reading engagement, whereas the EBs showed a trend toward greater reading anxiety and statistically significantly lower reading achievement. Further, for both EBs and EMs, reading anxiety related negatively to reading achievement, both directly and indirectly through reading engagement, controlling for grade level. However, both the direct and indirect effects were greater for EBs than EMs. We interpret these results in the context of theoretical views of potential mechanisms linking reading anxiety and achievement, giving attention especially to the multidimensional nature of reading engagement. Based on the current findings and those of other research, we conclude by contending that reading anxiety merits increased scrutiny by researchers and educators endeavoring to understand and strengthen students’ reading achievement and socioemotional development during the elementary school years.

Aiming at the problem that the existing urban rail transit station equipment and facility monitoring cannot achieve a global display of the station's multi-professional equipment operation status under a single screen. Constructing the station monitoring model based on the 2.5-dimensional perspective. Applying interface standardization technology, real-time monitoring configuration technology and visualized early warning technology for comprehensive monitoring of operation status of equipment and facilities, research on station panoramic monitoring scheme. The case shows, the system data collection information update time is within 1s, which proves that the system has reliability. The system can display the operation status and fault information of the key equipment in real time. It can help the dispatchers to study and judge the daily operation status of the station intelligently, provide auxiliary decision support for the overall planning of resources in case of emergency. Ensure the safe operation of the urban rail transit station.

So far, compressed air energy storage (CAES) system is another effective technology for large-scale energy storage which can improve grid flexibility and realize the grid generation of renewable energy. This paper reviews the developments of CAES technology including operation principles, application fields, technology performance of different types of CAES system and the current state-of-art. Finally, the potential key application prospects of CAES in future are discussed.