Computer technology and complex problem solving: Issues in the study of complex cognitive activity

Goals and plans organize much of complex problem solving behavior and are often inferable from action sequences. This paper addresses the strengths and limitations of inferring goals and plans from information that can be derived from computer traces of software used to solve mathematics problems. We examined mathematics problem solving activity about distance, rate, time relationships in a computer software environment designed to support understanding of functional relationships among these variables (e.g., distance =rate × time; time=distance/rate) using graphical representations of the results of simulations. Ten adolescent-aged students used the software to solve two distance, rate, time problems, and provided think-aloud protocols. To determine the inferability of understanding from the action traces, coders analyzed students' understanding from the computer traces alone (Trace-only raters) and compared these to analyses based on the traces plus the verbal protocols (Traceplus raters). Inferability of understanding from the action traces was related to level of student understanding how they used the graphing tool. When students had a good understanding of distance, rate, time relationships, it could be accurately inferred from the computer traces if they used the simulation tool in conjunction with the graphing tool. When students had a weak understanding, the verbal protocols were necessary to make accurate inferences about what was and was not understood. The computer trace also failed to capture dynamic exploration of the visual environment so students who relied on the graphing tool were inaccurately characterized by the Trace-only coders. Discussion concerns types of scaffolds that would be helpful learning environment for complex problems, the kind of information that is needed to adequately track student understanding in this content domain, and instructional models for integrating learning environments like these into classrooms.Members of the Cognition and Technology Group at Vanderbilt who have contributed to this project are (in alphabetical order) Helen Bateman, John Bransford, Thaddeus Crews, Allison Moore, Mitchell Nathan, and Stephen Owens. The research was supported, in part, by grants from the National Science Foundation (NSF-MDR-9252990) but no official endorsement of the ideas expressed herein should be inferred.     

How are feelings of difficulty and familiarity linked to learning behaviors and gains in a complex science learning task?

European Journal of Psychology of Education - The feelings of difficulty and familiarity (FOD and FOF) are two types of metacognitive experiences. Both may influence student engagement and the...     

Application of the G/G-expansion method for nonlinear diffusion equations with nonlinear source

The generalized diffusion equations, with nonlinear source terms which encompasses the Fisher, Newell-Whitehead, FitzHugh-Nagumo and Allen-Cahn equations as particular forms are solved by the G^′/G-expansion method. The exact solutions are in terms of hyperbolic, trigonometric and rational functions with external parameters. This paper concludes with the stationary topological soliton solution of the FitzHugh-Nagumo equation that is obtained by the Ansatz method.     

Ochronosis of the Hip Joint: Differential Diagnosis of Inflammatory Arthropathy with Lytic Lesion

Alkaptonuria or ochronosis is a rare inborn disorder of metabolism which is characterized by deficiency of homogentisic acid oxidase. There is accumulation of homogentisic acid in the connective tissues causing brownish black pigmentation and skeletal damage. The most serious complication of this disease is crippling degenerative arthropathy which presents in late years of life. There is no definitive treatment for the condition. Symptomatic management is the main stay. Surgical management such as arthroplasty is done for severe cases of ochronosis. We report a case of ochronosis of the hip joint presenting with inflammation and lytic lesion which can create confusion and lead to error in diagnosis.     

The effect of contextualized conversational feedback in a complex open-ended learning environment

Betty’s Brain is an open-ended learning environment in which students learn about science topics by teaching a virtual agent named Betty through the construction of a visual causal map that represents the relevant science phenomena. The task is complex, and success requires the use of metacognitive strategies that support knowledge acquisition, causal map construction, and progress monitoring. Previous research has established that middle school students struggle at such tasks without proper scaffolding and feedback. In Betty’s Brain, this feedback is provided by Betty and Mr. Davis, another virtual agent designed to provide guidance and suggestions as students work. This paper discusses our implementation of contextualized conversational (CC) feedback, and then presents the results of an experimental study exploring the effects of this feedback in two 8th-grade science classrooms. The results illustrate some advantages of the CC feedback in comparison with a baseline dialogue mechanism that presents similar strategies in a non-conversational, non-contextualized form. While both groups showed significant pre-to-post test learning gains, the difference in learning gains between the groups was not statistically significant. However, students who received CC feedback more often performed actions in accordance with the advised strategies, and they created higher quality causal maps.     

Liénard’s Generalisation: A Direct Derivation

In this pedagogical article, we elucidate the direct derivation of total power emitted by an accelerating charged particle, known as Liénard’s generalisation, using differentiation under integral sign technique.     

Validation of a wireless accelerometer network for energy expenditure measurement

The purpose of this study was to validate a wireless network of accelerometers and compare it to a hip-mounted accelerometer for predicting energy expenditure in a semi-structured environment. Adults (n = 25) aged 18–30 engaged in 14 sedentary, ambulatory, exercise, and lifestyle activities over a 60-min protocol while wearing a portable metabolic analyser, hip-mounted accelerometer, and wireless network of three accelerometers worn on the right wrist, thigh, and ankle. Participants chose the order and duration of activities. Artificial neural networks were created separately for the wireless network and hip accelerometer for energy expenditure prediction. The wireless network had higher correlations (r = 0.79 vs. r = 0.72, P < 0.01) but similar root mean square error (2.16 vs. 2.09 METs, P > 0.05) to the hip accelerometer. Measured (from metabolic analyser) and predicted energy expenditure from the hip accelerometer were significantly different for the 3 of the 14 activities (lying down, sweeping, and cycle fast); conversely, measured and predicted energy expenditure from the wireless network were not significantly different for any activity. In conclusion, the wireless network yielded a small improvement over the hip accelerometer, providing evidence that the wireless network can produce accurate estimates of energy expenditure in adults participating in a range of activities.     

Evaluation of Imprecision,Bias and Total Error of Clinical Chemistry Analysers

Context Two Biosystems analysers are used in our laboratory, a fully automated A25 and a semi-automated BTS-350. Internal quality control is done for both but external quality control only for A25. As BTS-350 is used for backup, it is important that the results of both analysers are not just comparable but also within predefined limits of systematic, random and total error (TE). Aim To evaluate the imprecision, bias and TE of the two Biosystem analysers. Materials and Methods Biosystems level-1 quality control sera lot number 70A was run in duplicate for 32 days on both the analysers. Between day imprecision (measured by the coefficient of variation), bias and TE were calculated for ten analytes and were checked to see whether they are within the acceptable minimum limits, desirable limits and optimum limits of allowable error based on specifications on Westgard’s website updated in 2014. Results On both the analysers, all the analytes except alkaline phosphatase were within the acceptable minimum limits of TE and most analytes were within the desirable limits of TE. Only TG on A25 was within the optimum limit of TE. Conclusion The two Biosystem analysers performed comparably with errors within acceptable limits for most analytes. BTS-350 was found to be a suitable and ready backup analyser for A25.