INVESTIGATING COGNITIVE AND METACOGNITIVE STRATEGY USE DURING AN ENGLISH PROFICIENCY TEST

 This paper reports on the results of a study of cognitive and metacognitive strategy use and its effect on the students’ test performance at the tertiary level in a Chinese EFL context. A 18-item survey involving 526 undergraduate non-English majors revealed that: (1) the students had a medium use of both cognitive and metacognitive strategies during the test; (2) cognitive and metacognitive strategy use was closely related to each other, but neither was a predictor for the other; and (3) though cognitive and metacognitive strategy use significantly correlated with the students’ performance in certain parts of the proficiency test, only the metacognitive strategy of evaluating one’s performance proved to be a positive predictor of the students’ performance in listening and reading comprehension and the overall written test. Based on the results, some implications and suggestions for future research are discussed. Keywords: Strategy use; Cognitive; Metacognitive; Test performance; Tertiary

Relations of POD modes and Lyapunov exponents to the nonlinear dynamic states in flow over oscillating tandem cylinders

Nonlinear dynamic states of flow field are analyzed using the Proper Orthogonal Decomposition (POD) to extract spatial coherent structures, and the temporal development of these spatial structures is further investigated by looking into the largestLyapunov exponents (LLEs) of the temporal coefficients of the POD modes. Additionally, the LLE of vorticity history at a specific point in the wake is also calculated to compare with the LLEs of the modes in the wake region. The flow field used for the analysis is flow around a two-tandem cylinder system with the downstream cylinder oscillating transversely. The numerical simulation is based on an immersed-boundary method for flow with the Reynolds number 100. Three states of typical nonlinear responses of this system are analyzed: lockin, transitional, and quasiperiodic. The results reveal that the paired POD modes can appear in the energetic modes, although this pattern fades in the transitional state. All the LLEs of the energetic modes in the lock-in state are zero, which means that the energetic modes in the lock-in state are stable. For the transitional state, after a long period of time, the LLEs of the first two energetic modes are close to zero, while the others are positive, showing that only the first two modes are relatively stable and that weak chaotic motions exist in the other modes. The LLEs of all the energetic modes in the quasiperiodic state are no larger than zero after a long period of time, resulting in asymptotical stableness of the energetic modes

Investigating Cognitive and Metacognitive Strategy Use During an English Proficiency Test

This paper reports on the results of a study of cognitive and metacognitive strategy use and its effect on the students\u27 test performance at the tertiary level in a Chinese EFL context. A 18-item survey involving 526 undergraduate non-English majors revealed that: (1) the students had a medium use of both cognitive and metacognitive strategies during the test; (2) cognitive and metacognitive strategy use was closely related to each other, but neither was a predictor for the other; and (3) though cognitive and metacognitive strategy use significantly correlated with the students\u27 performance in certain parts of the proficiency test, only the metacognitive strategy of evaluating one\u27s performance proved to be a positive predictor of the students\u27 performance in listening and reading comprehension and the overall written test. Based on the results, some implications and suggestions for future research are discussed

Proper orthogonal decomposition and recurrence map for the identification of spatial–temporal patterns in a low-Re wake downstream of two cylinders

Flow decomposition methods provide systematic ways to extract the flow modes, which can be regarded as the spatial distribution of a coherent structure. They have been successfully used in the study of wake, boundary layer, and mixing. However, real flow structures also possess complex temporal patterns that can hardly be captured using the spatial modes obtained in the decomposition. In order to analyze the temporal variation of coherent structures in a complex flow field, this paper studies the recurrence in phase space to identify the pattern and classify the evolution of the flow modes. The recurrence pattern depends on the time delay and initial condition. In some cases, the flow system will revisit a previous state regardless of the initial state, and in other cases, the system’s recurrence will depend on the initial state. These patterns are determined by the arrangement and interactions of coherent structures in the flow. The temporal order of the repetition pattern reflects the possible ways of flow evolution

Proper Orthogonal Decomposition and Recurrence Map for the Identification of Spatial–Temporal Patterns in a Low-Re Wake Downstream of Two Cylinders

Flow decomposition methods provide systematic ways to extract the flow modes, which can be regarded as the spatial distribution of a coherent structure. They have been successfully used in the study of wake, boundary layer, and mixing. However, real flow structures also possess complex temporal patterns that can hardly be captured using the spatial modes obtained in the decomposition. In order to analyze the temporal variation of coherent structures in a complex flow field, this paper studies the recurrence in phase space to identify the pattern and classify the evolution of the flow modes. The recurrence pattern depends on the time delay and initial condition. In some cases, the flow system will revisit a previous state regardless of the initial state, and in other cases, the system’s recurrence will depend on the initial state. These patterns are determined by the arrangement and interactions of coherent structures in the flow. The temporal order of the repetition pattern reflects the possible ways of flow evolution

Tractable Control for Autoregressive Language Generation

Despite the success of autoregressive large language models in text generation, it remains a major challenge to generate text that satisfies complex constraints: sampling from the conditional distribution $\Pr(\text{text} | \alpha)$ is intractable for even the simplest lexical constraints $\alpha$. To overcome this challenge, we propose to use tractable probabilistic models to impose lexical constraints in autoregressive text generation, which we refer to as GeLaTo. To demonstrate the effectiveness of this framework, we use distilled hidden Markov models to control autoregressive generation from GPT2. GeLaTo achieves state-of-the-art performance on CommonGen, a challenging benchmark for constrained text generation, beating a wide range of strong baselines by a large margin. Our work not only opens up new avenues for controlling large language models but also motivates the development of more expressive tractable probabilistic models.Comment: fixed typo in Table

Gas-Purged Headspace Liquid Phase Microextraction System for Determination of Volatile and Semivolatile Analytes

In order to achieve rapid, automatic, and efficient extraction for trace chemicals from samples, a system of gas-purged headspace liquid phase microextraction (GP-HS-LPME) has been researched and developed based on the original HS-LPME technique. In this system, semiconductor condenser and heater, whose refrigerating and heating temperatures were controlled by microcontroller, were designed to cool the extraction solvent and to heat the sample, respectively. Besides, inert gas, whose gas flow rate was adjusted by mass flow controller, was continuously introduced into and discharged from the system. Under optimized parameters, extraction experiments were performed, respectively, using GP-HS-LPME system and original HS-LPME technique for enriching volatile and semivolatile target compounds from the same kind of sample of 15 PAHs standard mixture. GC-MS analysis results for the two experiments indicated that a higher enrichment factor was obtained from GP-HS-LPME. The enrichment results demonstrate that GP-HS-LPME system is potential in determination of volatile and semivolatile analytes from various kinds of samples