The effect of scaffolding students’ context-generating cognitive activity in technology-enhanced case-based learning

This study investigates the hypothesis that students’ learning and problem-solving performance in ill-structured domains can be improved, if elaborative question prompts are used to activate students’ context-generating cognitive processes, during case study. Two groups of students used a web-based learning environment to criss-cross and study case-based material in the software project management domain. The experimental group was additionally prompted to consistently answer a set of questions based on a model of context-generating processes, meant to engage students in deeper processing of information presented in cases. Students were also classified as having either “complex” or “simple” EB profile (based on their epistemological beliefs record), thereby establishing a 2 × 2 factorial design. Results indicated that scaffolding treatment had a significant main effect on students’ performance, with the experimental group performing better in both domain knowledge acquisition and knowledge transfer post-test items. There is also tentative indication that EB profile and scaffolding treatment interact, with complex-EB learners benefiting most from the scaffolded condition. Overall, the study provides evidence that it is possible to improve individual learning in a technology environment for case-based learning, by implementing appropriate questioning strategies that trigger students to activate their context-generating cognitive processes, while studying the contextually rich material of cases.     

Learning patterns for discovering domain-oriented opinion words

Sentiment analysis is a challenging task that attracted increasing interest during the last years. The availability of online data along with the business interest to keep up with consumer feedback generates a constant demand for online analysis of user-generated content. A key role to this task plays the utilization of domain-specific lexicons of opinion words that enables algorithms to classify short snippets of text into sentiment classes (positive, negative). This process is known as dictionary-based sentiment analysis. The related work tends to solve this lexicon identification problem by either exploiting a corpus and a thesaurus or by manually defining a set of patterns that will extract opinion words. In this work, we propose an unsupervised approach for discovering patterns that will extract domain-specific dictionary. Our approach (DidaxTo) utilizes opinion modifiers, sentiment consistency theories, polarity assignment graphs and pattern similarity metrics. The outcome is compared against lexicons extracted by the state-of-the-art approaches on a sentiment analysis task. Experiments on user reviews coming from a diverse set of products demonstrate the utility of the proposed method. An implementation of the proposed approach in an easy to use application for extracting opinion words from any domain and evaluate their quality is also presented.     

Semi-autonomous Navigation of a Robotic Wheelchair

The present work considers the development of a wheelchair for people with special needs, which is capable of navigating semi-autonomously within its workspace. This system is expected to prove useful to people with impaired mobility and limited fine motor control of the upper extremities. Among the implemented behaviors of this robotic system are the avoidance of obstacles, the motion in the middle of the free space and the following of a moving target specified by the user (e.g., a person walking in front of the wheelchair). The wheelchair is equipped with sonars, which are used for distance measurement in preselected critical directions, and with a panoramic camera with a 360 degree field of view, which is used for following a moving target. After suitably processing the color sequence of the panoramic images using the color histogram of the desired target, the orientation of the target with respect to the wheelchair is determined, while its distance is determined by the sonars. The motion control laws developed for the system use the sensory data and take into account the non-holonomic kinematic constraints of the wheelchair, in order to guarantee certain desired features of the closed-loop system, such as stability. Moreover, they are as simplified as possible to minimize implementation requirements. An experimental prototype has been developed at ICS–FORTH, based on a commercially-available wheelchair. The sensors, the computing power and the electronics needed for the implementation of the navigation behaviors and of the user interfaces (touch screen, voice commands) were developed as add-on modules and integrated with the wheelchair.     

Frontostriatal deficits in unipolar major depression

Recent accounts of major depression have tended to focus on dysfunction of frontothalamic-striatal reentrant circuits as a possible source of the disorder. Evidence of frontostriatal involvement in unipolar major depression from lesion and neuropsychological studies, and functional and structural imaging studies is examined. The high incidence of depressive symptomatology following left frontal and basal ganglia lesions implicate these as possible sites of dysfunction. Neuropsychological evidence indicates similar deficits in patients with major depression, perhaps with dorsolateral prefrontal deficits most prominent. Structural imaging studies report frontal and basal ganglia (BG) abnormalities particularly in cases of late-age onset depression. Resting state functional imaging studies show deficits in dorsolateral, anterior cingulate (medial frontal), and BG structures. Activation imaging studies show less consistent evidence of dorsolateral deficit, while anterior cingulate deficit is more consistently demonstrated. Variability in findings across studies may reflect differences between subtypes of depression and differences in methodology. Possible involvement of the BG in the psychomotor retardation of depression is examined. It is concluded that, while there is evidence of frontostriatal deficit in major depression, the exact nature of such deficits is uncertain. Issues such as component vs. system dysfunction need to be addressed.     

Conversational agents for academically productive talk: a comparison of directed and undirected agent interventions

Conversational agents that draw on the framework of academically productive talk (APT) have been lately shown to be effective in helping learners sustain productive forms of peer dialogue in diverse learning settings. Yet, literature suggests that more research is required on how learners respond to and benefit from such flexible agents in order to fine-tune the design of automated APT intervention modes and, thus, enhance agent pedagogical efficacy. Building on this line of research, this work explores the impact of a configurable APT agent that prompts peers to build on prior knowledge and logically connect their contributions to important domain concepts discussed in class. A total of 96 computer science students engaged in a dialogue-based activity in the context of a Human-Computer Interaction (HCI) university course. During the activity, students worked online in dyads to accomplish a learning task. The study compares three conditions: students who collaborated without any agent interference (control), students who received undirected agent interventions that addressed both peers in the dyad (U treatment), and students who received directed agent interventions addressing a particular learner instead of the dyad (D treatment). The results suggest that although both agent intervention methods can improve students’ learning outcomes and dyad in-task performance, the directed one is more effective than the undirected one in enhancing individual domain knowledge acquisition and explicit reasoning. Furthermore, findings show that the positive effect of the agent on dyad performance is mediated by the frequency of students’ contributions displaying explicit reasoning, while most students perceive agent involvement favorably.     

Remote monitoring of electromagnetic signals and seismic events using smart mobile devices

This study presents the design and development of a novel mobile wireless system to be used for monitoring seismic events and related electromagnetic signals, employing smart mobile devices like personal digital assistants (PDAs) and wireless communication technologies such as wireless local area networks (WLANs), general packet radio service (GPRS) and universal mobile telecommunications system (UMTS). The proposed system enables scientists to access critical data while being geographically independent of the sites of data sources, rendering it as a useful tool for preliminary scientific analysis.     

Polymorphismsof the CD24 Gene Are Associated with Risk of Multiple Sclerosis: A Meta-Analysis

CD24 is a cell-surface protein mainly expressed in cells of the immune and central nervous system (CNS), cells that play a critical role in the development of multiple sclerosis (MS). In the current study, we investigated four polymorphisms of the CD24 gene regarding their associations with MS. To this end, univariate and multivariate meta-analysis were applied along with modifications to include data from family-trios so as to increase the robustness of the meta-analysis. We found that the polymorphism 226 C>T (Ala57Val) of the CD24 gene is associated with MS according to the recessive mode of inheritance (odds ratio = 1.75; 95% CI: 1.09, 2.81). Moreover, the 1527–1528 TG>del polymorphism is inversely associated with MS according to the dominant mode of inheritance (odds ratio = 0.57; 95% CI 0.39, 0.83). Conversely, the 1056 A>G and 1626 A>G polymorphisms were not found to be associated with MS. We conclude that the CD24 226 C>T polymorphism increases the risk of MS, while the 1527–1528 TG>del polymorphism seems to have a protective role against MS, suggesting that these two polymorphisms can be used as predictive biomarkers for MS development.     

Neuropsychological function in young patients with unipolar major depression

BACKGROUND: While neuropsychological studies have consistently reported impaired cognition in elderly patients with unipolar depression, studies of cognitive function in younger patients with depression have produced equivocal results. The aim of this study was to examine the presence and nature of cognitive deficits in young patients with depression. METHODS: Neuropsychological function was assessed in 20 young patients with unipolar depression, in comparison to 20 age-, education- and IQ- matched controls. Subtests from the Cambridge Neuropsychological Test Automated Battery (CANTAB) were employed, as this battery has proved sensitive to deficits in middle-aged and elderly patients with depression. RESULTS: The patients were not impaired for short-term memory capacity, spatial working memory, planning ability, cognitive speed, delayed matching to sample or recognition memory. Compared to controls, the patients showed impaired subsequent movement latencies on the Tower of London task, suggesting deficits in the ability to sustain motor responses in depression. The depression group were also impaired on the task of attentional set shifting, requiring more trials to criterion at the intradimensional stage of the task and being more likely to fail the task at the extradimensional shift stage than controls. Further analysis indicated that half of the depression group failed to complete all stages of the set shifting task. These patients were more likely to have required in-patient hospitalization at some time during their illness. CONCLUSIONS: These results indicate that there are specific cognitive deficits in young patients with depression and that their presence may be related to a history of hospitalization.     

Enriching feedback in audience response systems: Analysis and implications of objective and subjective metrics on students' performance and attitudes

The aim of the present study (n = 113) was to examine how (objective and subjective) information on peers' preparation, confidence, and past performance can support students in answering correctly in audience response systems (aka clickers). The result analysis shows that in the “challenging” questions, in which answers diverged, students who received additional information about peers' self‐reported preparation and/or confidence outperformed students who were only given the objective percentage with or without past performance feedback. In addition, students expressed a positive attitude towards the activity, commenting its usefulness in better understanding course material and identifying misconceptions.