Decentralized low-complexity tracking of uncertain interconnected high-order nonlinear systems with unknown high powers

A global decentralized low-complexity tracker design methodology is proposed for uncertain interconnected high-order nonlinear systems with unknown high powers. It is assumed that interconnected nonlinearities are bounded by completely unknown nonlinearities, rather than, a linear combination of high-ordered state variables. Compared with the existing decentralized results for interconnected nonlinear systems with known high powers, the decentralized robust controller, which achieves the pre-designable transient and steady-state tracking performance for each subsystem, is designed by employing nonlinear error surfaces with time-varying performance functions, regardless of unknown nonlinear interactions and high powers related to virtual and actual control variables. The proposed decentralized continuous robust low-complexity tracker is realized without the use of any adaptive or function approximation techniques for estimating unknown parameters and nonlinearities. The stability and preassigned tracking performance of the resulting decentralized low-complexity control system are thoroughly analyzed in the Lyapunov sense. Finally, simulation results on coupled underactuated mechanical systems are provided to show the effectiveness of the proposed theoretical result.     

Two‐dimensional sectioned images and three‐dimensional surface models for learning the anatomy of the female pelvis

In the Visible Korean project, serially sectioned images of the pelvis were made from a female cadaver. Outlines of significant structures in the sectioned images were drawn and stacked to build surface models. To improve the accessibility and informational content of these data, a five‐step process was designed and implemented. First, 154 pelvic structures were outlined with additional surface reconstruction to prepare the image data. Second, the sectioned and outlined images (in a browsing software) as well as the surface models (in a PDF file) were placed on the Visible Korean homepage in a readily‐accessible format. Third, all image data were visualized with interactive elements to stimulate creative learning. Fourth, two‐dimensional (2D) images and three‐dimensional (3D) models were superimposed on one another to provide context and spatial information for students viewing these data. Fifth, images were designed such that structure names would be shown when the mouse pointer hovered over the 2D images or the 3D models. The state‐of‐the‐art sectioned images, outlined images, and surface models, arranged and systematized as described in this study, will aid students in understanding the anatomy of female pelvis. The graphic data accompanied by corresponding magnetic resonance images and computed tomographs are expected to promote the production of 3D simulators for clinical practice. Anat Sci Educ 6: 316–323. © 2013 American Association of Anatomists.     

The relationship between university student learning outcomes and participation in social network services,social acceptance and attitude towards school life

Educators try to use social network services (SNSs) in their teaching because they are regarded as beneficial to student learning. However, little research to date has empirically investigated whether the use of an SNS increases university student learning outcomes. A total of 730 university students in the capital area of South Korea participated in the present study. Based on social learning theory, we developed a general structural model that included SNS participation (SP) as an exogenous variable and a range of endogenous variables: cognitive domain learning outcomes, affective domain learning outcomes, social domain learning outcomes, social acceptance (SA) and attitude towards university life (AT). The study results confirmed that the model adequately explained causal relationships between student learning outcomes and SA, AT and SP. SA was identified as a key variable because of its direct effect on learning outcomes. However, SP was considered more important because of its large indirect effects on all learning outcomes through both SA and AT.     

Less conservative stabilization conditions for Markovian jump systems with partly unknown transition probabilities

This paper is devoted to the robust stabilization problem for a class of MJLSs with mode transition probabilities taken to be partly known, unknown, and unknown but with known bounds. To meet the needs of less conservative stabilization conditions, this paper proposes a valuable approach that (1) can express the conditions in terms of matrix inequalities with homogeneous polynomial dependence on partly unknown transition probabilities and (2) can include all possible slack variables related to transition probability constraints in the relaxation process coupled with deriving a finite set of linear matrix inequalities (LMIs). Finally, two numerical examples are reported to illustrate the effectiveness of the derived stabilization conditions.     

The cultural politics of national testing and test result release policy in South Korea: a critical discourse analysis

This paper examines the ideological construction of educational discourses embedded within the South Korean print media. Significantly, these discourses have recently promoted the resurrection of a sweeping national testing and test results release policy. Through careful examination of the “test plus release” policy, the authors show how the government has achieved hegemonic power by shaping public opinion through the national testing contexts. Drawing on a critical discourse analysis of educational policy texts from the government and top 10 print media sources, this paper analyses how discourses on “accountability”, “the right to know” and “the fairness of the tests” have been produced, reproduced and recontextualized to favour particular perspectives. The authors also examine how government and influential print media discourses interact with political and cultural factors such as “acclaiming the evaluative state”, “education fever” and “meritocratic beliefs” to achieve public consent for the new “test plus release” policy.     

The effectiveness of a marketing virtual reality learning simulation: A quantitative survey with psychophysiological measures

Virtual reality (VR) technology has been shown to be a promising teaching method in STEM subjects. Extending these findings, the current study is the first to develop and examine the feasibility of using a VR simulation in marketing (ie, a non-STEM subject). Specifically, the levels of immersion and three learning outcomes (learning attitude, enjoyment and performance) were compared between the marketing students who learned the same content through a VR simulation prototype versus a traditional static video presentation. Learning enjoyment was measured using facial electromyography, which served as a more objective measures for the feeling of enjoyment. Compared to the video condition, the results showed that VR resulted in a higher experience of immersion, learning attitude and learning enjoyment. Furthermore, immersion was found to fully mediate the positive effects of the VR simulation on learning attitude, but not enjoyment. Surprisingly, students in the video condition performed better on the knowledge-based test than those in the VR condition. The current study suggests that the current prototype of the VR simulations should be used as supplementary resource to increase the learning attitude and enjoyment, but not as a main teaching material to enhance knowledge-based performance in the marketing discipline.     

Risk and Protective Factors for Homophobic Bullying in Schools: An Application of the Social–Ecological Framework

Homophobic bullying is a serious concern for students, parents, teachers, and school officials. This article reviews evidence on the status of this problem and how it may be addressed in a multilevel and multidisciplinary manner growing out of a social–ecological perspective on homophobic bullying as a social phenomenon. The ecological framework developed by Urie Bronfenbrenner (1977, 1979) is applied to organize this effort, which includes micro-, exo-, and macro-systems in which behavior and development are embedded. The inherent fluidity of experience postulated by Bronfenbrenner’s ecological approach offers hope that as practices and policy to promote diversity move forward, they will reshape the social ecology of sexual minority youth.