An extension of the technology acceptance model for online learning environments

This study advances the understanding of the process by which students accept and use e-learning environments. This is a key aspect in studying the online behaviour of students, as it directly influences their conduct in their capacity as users of learning products. To address the lack of empirical data on the adoption of this type of learning environment, we present and validate a model of the phenomenon. The study considers the utilitarian aspects included in the technology acceptance model (TAM) and also an aspect of intrinsic motivation for an individual, flow, to enhancing the explanatory power of the models presented.

Based on a sample of 2,574 students, structural equation modelling is used to test the model. We identify the effect of flow on perceived ease of use, perceived usefulness and on the actual usage of the e-learning environment, demonstrating the importance of this factor as a complement to the components of the TAM.     

Barriers and Enablers to Data‐Driven Decision Making by High School Counselors and Advisors

This article presents a study that had as its purpose to assist a large urban school district's leadership in systematically supporting school counselors and advisors conducting data‐driven decision making. Binder's Six Boxes® model served as the conceptual framework to collect and analyze information pertaining to barriers and enablers across environmental and behavioral factors. Barriers included lack of clear expectations and feedback, an overabundance of technology without time to practice, and clerical duties. Enablers included supportive leadership, knowledgeable counselors willing to participate, and leadership with positive perceptions.     

Probing transient protein-mediated DNA linkages using nanoconfinement

We present an analytic technique for probing protein-catalyzed transient DNA loops that is based on nanofluidic channels. In these nanochannels, DNA is forced in a linear configuration that makes loops appear as folds whose size can easily be quantified. Using this technique, we study the interaction between T4 DNA ligase and DNA. We find that T4 DNA ligase binding changes the physical characteristics of the DNA polymer, in particular persistence length and effective width. We find that the rate of DNA fold unrolling is significantly reduced when T4 DNA ligase and ATP are applied to bare DNA. Together with evidence of T4 DNA ligase bridging two different segments of DNA based on AFM imaging, we thus conclude that ligase can transiently stabilize folded DNA configurations by coordinating genetically distant DNA stretches.     

Super twisting control of a parametrically excited overhead crane

The principal contribution of this note is to avoid the parametric resonance effect and attenuate the payload oscillations in an overhead-crane system subject to periodic variations in the base support. Considering an appropriate sliding output with relative degree one, we present the sliding mode control design based on the Super-Twisting Algorithm (STA), ensuring finite time convergence to the desired sliding surface for the linear periodic system with Lipschitz continuous matched and unmatched uncertainties bounded together by their gradients by known functions. The suggested approach also provides chattering phenomenon attenuation. Obtained results are verified experimentally.     

Polytopic invariant and contractive sets for closed-loop discrete fuzzy systems

In this work a procedure for obtaining polytopic λ-contractive sets for Takagi–Sugeno fuzzy systems is presented, adapting well-known algorithms from literature on discrete-time linear difference inclusions (LDI) to multi-dimensional summations. As a complexity parameter increases, these sets tend to the maximal invariant set of the system when no information on the shape of the membership functions is available. λ-contractive sets are naturally associated to level sets of polyhedral Lyapunov functions proving a decay-rate of λ. The paper proves that the proposed algorithm obtains better results than a class of Lyapunov methods for the same complexity degree: if such a Lyapunov function exists, the proposed algorithm converges in a finite number of steps and proves a larger λ-contractive set.