Stabilities and Settling Times of Nonlinear and Time-varying Feedback Systems

The bounded-input bounded-output stability, finite time stability and settling time of a single-loop feedback system consisting of a nonlinear time-varying gain followed by a linear time-invariant system are investigated via a nonlinear integral inequality. The gain has the form k₀+k₁(t)+k₂(t)g(bd) where g(bd) is a monotonic increasing function. The system is bounded-input bounded-output stable provided the time-varying gains are L¹(0, t8) functions and is finite time stable for bounded gains. The nonlinear integral inequality, which is used to obtain explicit and useful bounds on the output of the system, is also employed to determine the settling time.     

Respect and responsibility: Teaching citizenship in South African high schools

Respect is a core concept in citizenship debates. South African high school educators often draw upon respect as a key value within citizenship education. Their teaching of this value is often conflated with promotion of the practice of responsible citizenship. The constructions of respect and responsibility in these situations are imbued with assumptions around authority and power relations, such that learners’ are expected to take responsibility for demonstrating respect for in an unequal rather than reciprocal understanding of respect. Thus, negotiations of different kinds of respect are highlighted. The need for schools to embody a culture or ethos of respect is noted if learners are to be expected to recognise and adopt respect as a key element to citizenship in theory and in practice.     

Student socialization in interdisciplinary doctoral education

Interdisciplinary approaches are often seen as necessary for attacking the most critical challenges facing the world today, and doctoral students and their training programs are recognized as central to increasing interdisciplinary research capacity. However, the traditional culture and organization of higher education are ill-equipped to facilitate interdisciplinary work. This study employs a lens of socialization to study the process through which students learn the norms, values, and culture of both traditional disciplines and integrated knowledge production. It concludes that many of the processes of socialization are similar, but that special attention should be paid to overcoming organizational barriers to interdisciplinarity related to policies, space, engagement with future employers, and open discussion of the politics of interdisciplinarity.     

Circuits of Dominance in Education and Poverty: Control Logic and Counter Narrative

In this article I represented educational narratives from two students who completed college coursework while they were incarcerated in a closed correctional facility in North Carolina. Alongside their narratives, I shared literature that addressed inadequacies in the United States social welfare programs, an absence of a living wage, and whitestream dominance in US public schools and analyzed the narratives of these students’ childhoods. These narratives were situated at the intersections of poverty and illegal work. Often these intersections remain invisible in policy discourse and educational contexts in the high accountability/high stakes testing movement that positions the curriculum, and not the child, as the most important thing in the classroom. Subsequently, I challenged educators and researchers committed to the pursuit of equity to question how the children in our classrooms and youth in our prisons were raced, gendered, and classed, and to engage in careful and layered understandings of our students’ lives.     

Closing the Gap Between Photojournalist Research and Photojournalism Practice: Exploring the Motivations of the Subjects of Sensitive Photo Essays

This study is the first to inquire about the factors that influence people’s willingness to allow professional photojournalists to tell their stories through the medium of the photo essay. Guided by Self-Disclosure Theory, in-depth interviews were conducted with the subjects of 15 peer-judged award-winning photo essays. These were drawn from the multiple picture categories of the National Press Photographers Association (NPPA) Monthly Clip Contest, the annual NPPA Best of Photojournalism Contest, and the annual World Press Photo Contest between 2013 and 2017. The topics of the photo essays were sensitive in nature. Analysis reveals support and appreciation amongst photo-essay subjects for the profession of photojournalism. Motivations derived from the sensitivity and professionalism with which each interviewee was initially approached, a need to tell a different side of the story, a desire to inspire others or invoke change, and the memory-keeping and permanence afforded through published professional photojournalism.     

State of the library and information science blogosphere after social networks boom: A metric approach

A metric analysis of blogs on library and information science (LIS) between November 2006 and June 2009 indexed on the Libworm search engine characterizes the community's behavior quantitatively. An analysis of 1108 personal and corporate blogs with a total of 275,103 posts is used to calculate survival rate, production (number of posts published), and visibility via such indicators as links received, Technorati authority, and Google's PagePank. Over the study period, there was a 52% decrease in the number of active blogs. Despite the drop in production over this period, the average number of posts per blog remained constant (14 per month). The most representative blogs in the discipline are identified. The emergence of such platforms as Facebook and Twitter seems to have meant that both personal and corporate blogs have lost some of their prominence.     

Creativity, expertise, and attention: exploring their development and their relationships

Recent evidence from neuroscience suggests that creativity is developed early in life and that the greatest improvements in creativity can be expected during this time. Therefore, the aim of this study was to investigate the creative development of children depending on their level of expertise and attention processes. Moreover, the significance of general and specific attention components and special training effects in the development of specific and non-specific creative thinking remain unclear. Thus, skilled (team handball) and non-skilled children (n = 120) aged 7, 10, and 13 completed two divergent thinking tasks (specific/non-specific) and two attention tasks (specific/non-specific) in a cross-sectional design. It is evident that general and sport-specific creativity have similar paths of development. Skilled players with high attention scores performed better than skilled players with low attention scores, in accordance with specific creative thinking abilities. In contrast, and in accordance with general creative thinking abilities, non-skilled players with less attentional skills outperformed non-skilled players.     

软土地面中机械化双叠隧道的三维数值模拟

研究目的：通过三维数值模拟,研究隧道施工过程对双叠隧道的影响。创新要点：使用全三维数值模拟方法研究软土中双叠隧道施工对先挖隧道或地面的影响。研究方法：1.运用FLAC软件创建双叠隧道的三维数值模型（图1）;2.分情况模拟机械化双叠隧道的挖掘过程;3.研究不同情况下的地面沉降,水平地面位移,以及隧道衬砌的法向位移、法向力、纵向力和弯曲力矩等。重要结论：1.新隧道施工对现有的隧道有很大的影响,最大影响出现在先挖上层隧道的情况下;2.一般来说,上层隧道的挖掘会比下层隧道产生更大的地面沉降;3.下层隧道产生的法向力总是比上层隧道大;4.在多数情况下,下层隧道产生的法向位移和弯曲力矩要比上层隧道小。