Framing university small group talk : knowledge construction through lexical concepts

PhD ThesisKnowledge construction in educational discourse continues to interest practitioners and researchers due to the conceptually “natural” connection between knowledge and learning for professional development. Frames have conceptual and practical advantages over other units of inquiry concerning meaning negotiation for knowledge construction. They are relatively stable data-structures representing prototypical situations retrieved from real world experiences, cover larger units of meaning beyond the immediate sequential mechanism at interaction, and have been inherently placed at the semantic-pragmatic interface for empirical observation. Framing in a particular context – university small group talk has been an under-researched field, while the relationship between talk and knowledge through collaborative work has been identified below/at the Higher Educational level. Involving higher level cognitive activities and distinct interactional patterns, university small group talk is worth close examination and systematic investigation. This study applies Corpus Linguistics and Interactional Linguistics approaches to examine a subset of a one-million-word corpus of university small group talk at a UK university. Specifically, it provides a detailed examination of the participants’ framing behaviours for knowledge construction through their talk of disciplinary lexical concepts. Analysis reveals how the participants draw upon schematized knowledge structures evoked by particular lexical choices and how they invoke expanded scenarios via pragmatic mappings in the ongoing interaction. Additionally, it is demonstrated how the framing moves are related to the structural uniqueness of university small group talk, the contextualized speaker roles and the institutional procedures and routines. This study deepens the understanding of the relationship between linguistically constructed knowledge and the way interlocutors conceptualize the world through institutionalized collaboration, building upon the existing research on human reliance upon structures to interpret reality at both the conceptual and the action levels. The study also addresses interaction research in Higher Educational settings, by discussing how the cognitive-communicative duality of framing is sensitive to various contextual resources, distinct discourse structures and task procedures through the group dynamics

Thermodynamics of Black Holes in Massive Gravity

We present a class of charged black hole solutions in an ($n+2)$-dimensional massive gravity with a negative cosmological constant, and study thermodynamics and phase structure of the black hole solutions both in grand canonical ensemble and canonical ensemble. The black hole horizon can have a positive, zero or negative constant curvature characterized by constant $k$. By using Hamiltonian approach, we obtain conserved charges of the solutions and find black hole entropy still obeys the area formula and the gravitational field equation at the black hole horizon can be cast into the first law form of black hole thermodynamics. In grand canonical ensemble, we find that thermodynamics and phase structure depends on the combination $k -\mu^2/4 +c_2 m^2$ in the four dimensional case, where $\mu$ is the chemical potential and $c_2m^2$ is the coefficient of the second term in the potential associated with graviton mass. When it is positive, the Hawking-Page phase transition can happen, while as it is negative, the black hole is always thermodynamically stable with a positive capacity. In canonical ensemble, the combination turns out to be $k+c_2m^2$ in the four dimensional case. When it is positive, a first order phase transition can happen between small and large black holes if the charge is less than its critical one. In higher dimensional ($n+2 \ge 5$) case, even when the charge is absent, the small/large black hole phase transition can also appear, the coefficients for the third ($c_3m^2$) and/or the fourth ($c_4m^2$) terms in the potential associated with graviton mass in the massive gravity can play the same role as the charge does in the four dimensional case.Comment: Latex 19 pages with 8 figure

Formation of in-volume nanogratings with sub-100 nm periods in glass by femtosecond laser irradiation

We present direct experimental observation of the morphological evolution during the formation of nanogratings with sub-100-nm periods with the increasing number of pulses. Theoretical simulation shows that the constructive interference of the scattering light from original nanoplanes will create an intensity maximum located between the two adjacent nanoplanes, resulting in shortening of the nanograting period by half. The proposed mechanism enables explaining the formation of nanogratings with periods beyond that predicted by the nanoplasmonic model.Comment: 4 pages, 3 figure

Reply to comment on “spatio-temporal variation of groundwater recharge in response to variability in precipitation, land use and soil in Yanqing Basin, Beijing, China

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Dialogue Act Recognition via CRF-Attentive Structured Network

Dialogue Act Recognition (DAR) is a challenging problem in dialogue interpretation, which aims to attach semantic labels to utterances and characterize the speaker's intention. Currently, many existing approaches formulate the DAR problem ranging from multi-classification to structured prediction, which suffer from handcrafted feature extensions and attentive contextual structural dependencies. In this paper, we consider the problem of DAR from the viewpoint of extending richer Conditional Random Field (CRF) structural dependencies without abandoning end-to-end training. We incorporate hierarchical semantic inference with memory mechanism on the utterance modeling. We then extend structured attention network to the linear-chain conditional random field layer which takes into account both contextual utterances and corresponding dialogue acts. The extensive experiments on two major benchmark datasets Switchboard Dialogue Act (SWDA) and Meeting Recorder Dialogue Act (MRDA) datasets show that our method achieves better performance than other state-of-the-art solutions to the problem. It is a remarkable fact that our method is nearly close to the human annotator's performance on SWDA within 2% gap.Comment: 10 pages, 4figure