The impact of an in-service professional development course on writing teacher attitudes and pedagogy

In education, it is commonly believed that the quality of teachers' learning experiences directly affects the quality of their students' learning experiences. Specifically, teachers' continuing learning may bring about positive effects on student learning. For the past ten years or so, research has emphasized the effects of professional development courses on teachers in hard science disciplines. Little attention has been paid to study the influences of those courses on teachers in the 'soft' sciences, such as English language, especially in the area of teaching of writing. Against this background, I undertook a study to investigate how an in-service professional development course influences the teaching attitudes of writing teachers who enrolled on the course and their teaching practice. I argue that the professional development course empowered the teachers with skills useful for the teaching of writing. I also argue that the course positively changed the attitudes of the teachers towards their practice in the teaching of writing. It is suggested that teachers need to engage in continuing professional development to improve the quality of their teaching

On the Convergence of Decentralized Gradient Descent

Consider the consensus problem of minimizing $f(x)=\sum_{i=1}^n f_i(x)$ where each $f_i$ is only known to one individual agent $i$ out of a connected network of $n$ agents. All the agents shall collaboratively solve this problem and obtain the solution subject to data exchanges restricted to between neighboring agents. Such algorithms avoid the need of a fusion center, offer better network load balance, and improve data privacy. We study the decentralized gradient descent method in which each agent $i$ updates its variable $x_{(i)}$, which is a local approximate to the unknown variable $x$, by combining the average of its neighbors' with the negative gradient step $-\alpha \nabla f_i(x_{(i)})$. The iteration is $$x_{(i)}(k+1) \gets \sum_{\text{neighbor} j \text{of} i} w_{ij} x_{(j)}(k) - \alpha \nabla f_i(x_{(i)}(k)),\quad\text{for each agent} i,$$ where the averaging coefficients form a symmetric doubly stochastic matrix $W=[w_{ij}] \in \mathbb{R}^{n \times n}$. We analyze the convergence of this iteration and derive its converge rate, assuming that each $f_i$ is proper closed convex and lower bounded, $\nabla f_i$ is Lipschitz continuous with constant $L_{f_i}$, and stepsize $\alpha$ is fixed. Provided that $\alpha < O(1/L_h)$ where $L_h=\max_i\{L_{f_i}\}$, the objective error at the averaged solution, $f(\frac{1}{n}\sum_i x_{(i)}(k))-f^*$, reduces at a speed of $O(1/k)$ until it reaches $O(\alpha)$. If $f_i$ are further (restricted) strongly convex, then both $\frac{1}{n}\sum_i x_{(i)}(k)$ and each $x_{(i)}(k)$ converge to the global minimizer $x^*$ at a linear rate until reaching an $O(\alpha)$-neighborhood of $x^*$. We also develop an iteration for decentralized basis pursuit and establish its linear convergence to an $O(\alpha)$-neighborhood of the true unknown sparse signal

How and when do markets tip? Lessons from the Battle of the Bund

In a famous episode of financial history which lasted over eight years, the market for the future on the Bund moved entirely from LIFFE, a London-based derivatives exchange, to DTB, a Frankfurt-based exchange. This paper studies the determinants of the observed dynamics, using a novel panel dataset that contains individual trading firms' membership status at each exchange together with other firms characteristics, and pricing, marketing and product portfolio strategies by each exchange. Our data allows us to distinguish between different explanations for the observed phenomenon. Our results indicate that the main driver was a "market coverage" effect: thanks to the combination its electronic market structure and EU-wide access deregulation, DTB increased the relevant size of the market for exchange members and disproportionately attracted those firms who originally did not exist or used to submit their orders through a broker. Differential liquidity and product portfolio strategies by the exchanges played a secondary role. JEL Classification: G21, G28, L13, L43adoption cost, Bund, electronic trading, Exchange competition, network effect, open outcry, tipping

Automatic Detection of Pain from Spontaneous Facial Expressions

This paper presents a new approach for detecting pain in sequences of spontaneous facial expressions. The motivation for this work is to accompany mobile-based self-management of chronic pain as a virtual sensor for tracking patients' expressions in real-world settings. Operating under such constraints requires a resource efficient approach for processing non-posed facial expressions from unprocessed temporal data. In this work, the facial action units of pain are modeled as sets of distances among related facial landmarks. Using standardized measurements of pain versus no-pain that are specific to each user, changes in the extracted features in relation to pain are detected. The activated features in each frame are combined using an adapted form of the Prkachin and Solomon Pain Intensity scale (PSPI) to detect the presence of pain per frame. Painful features must be activated in N consequent frames (time window) to indicate the presence of pain in a session. The discussed method was tested on 171 video sessions for 19 subjects from the McMaster painful dataset for spontaneous facial expressions. The results show higher precision than coverage in detecting sequences of pain. Our algorithm achieves 94% precision (F-score=0.82) against human observed labels, 74% precision (F-score=0.62) against automatically generated pain intensities and 100% precision (F-score=0.67) against self-reported pain intensities

HUMAN INTERACTIONS IN PHYSICAL AND VIRTUAL SPACES: A GIS-BASED TIME-GEOGRAPHIC EXPLORATORY APPROACH

Information and communication technologies (ICT) such as cell phone and the Internet have extended opportunities of human activities and interactions from physical spaces to virtual spaces. The relaxed spatio-temporal constraints on individual activities may affect human activity-travel patterns, social networks, and many other aspects of society. A challenge for research of human activities in the ICT age is to develop analytical environments that can help visualize and explore individual activities in virtual spaces and their mutual impacts with physical activities. This dissertation focuses on extending the time-geographic framework and developing a spatio-temporal exploratory environment in a space-time geographic information system (GIS) to facilitate research of human interactions in both physical and virtual spaces. In particular, this dissertation study addresses three research questions. First, it extends the time-geographic framework to assess the impacts of phone usage on potential face-to-face (F2F) meeting opportunities, as well as dynamic changes in potential F2F meeting opportunities over time. Secondly, this study extends the time-geographic framework to conceptualize and represent individual trajectories in an online social network space and to explore potential interaction opportunities among people in a virtual space. Thirdly, this study presents a spatio-temporal environment in a space-time GIS to facilitate exploration of the relationships between changes in physical proximity and changes in social closeness in a virtual space. The major contributions of this dissertation include: (1) advancing the time-geographic framework in its ability of exploring processes of virtual communication alerting physical activity opportunities; (2) extending some concepts of the classical time geography from a physical space to a virtual space for representing and exploring virtual interaction patterns; (3) developing a space-time GIS that is useful for exploring patterns of individual activities and interactions in both physical and virtual spaces, as well as the interactions between these two spaces

Universal Cycles for Minimum Coverings of Pairs by Triples, with Application to 2-Radius Sequences

A new ordering, extending the notion of universal cycles of Chung {\em et al.} (1992), is proposed for the blocks of $k$-uniform set systems. Existence of minimum coverings of pairs by triples that possess such an ordering is established for all orders. Application to the construction of short 2-radius sequences is given, with some new 2-radius sequences found through computer search.Comment: 18 pages, to appear in Mathematics of Computatio

Cohesion, Coherence, and Children Narrative Writing Quality: Topical Structure Analysis

Cohesion and coherence of writing have been important topics in academic writing research. Few studies have examined the relationship between cohesion, coherence, and quality of elementary school pupils’ writing using the topical structure analysis. This study reports the results of an analysis of English language narrative compositions of 19 elementary school pupils, to identify the link between cohesion, coherence, and children’s narrative writing quality. Independent-Samples t tests were performed. Results show that students with low writing quality produced more indirect, less unrelated sequential progression. They tended to overuse ‘and’, ‘so’, and ‘then’ in the current study. The study contributes to our understanding of teaching cohesion and coherence in writing among young learners

Peer review activity and a search‐engine based corpus system

For the past two decades, we have witnessed a number of peer review research studies in both first and second/foreign language writing classrooms. Few studies, however, have been done to build a custom search‐engine based corpus system that performs searches on relevant texts for academic writing tasks, such as peer review activity. The study investigates students’ perception of the peer feedback task using a search‐engine based corpus system called Word Engine. The participants were 322 first‐year undergraduates across disciplines who took an academic writing course at a large public university in Singapore. Data were collected from background questionnaires about the participants, peer reviews on first drafts of the students’ papers, and students’ final papers after incorporating feedback from the peer review. Findings showed that students believed that peer feedback activity was useful. They made revisions on various aspects including discussion of results, the development of ideas, macro‐rhetorical goal of the paper, and the use of academic language such as hedges. Students used Word Engine because it excluded all nonacademic websites. The study contributes to the field of academic writing and corpus linguistics, particularly how peer feedback with the use of Word Engine can promote student autonomy in learning