Feedback control in neural systems is ubiquitous. Here we study the mathematics of nonlinear feedback control. We compare models in which the input is multiplied by a dynamic gain (multiplicative control) with models in which the input is divided by a dynamic attenuation (divisive control). The gain signal (resp. the attenuation signal) is obtained through a concatenation of an instantaneous nonlinearity and a linear low-pass filter operating on the output of the feedback loop. For input steps, the dynamics of gain (...) and attenuation can be very different, depending on the mathematical form of the nonlinearity and the ordering of the nonlinearity and the filtering in the feedback loop. Further, the dynamics of feedback control can be strongly asymmetrical for increment versus decrement steps of the input. Nevertheless, for each of the models studied, the nonlinearity in the feedback loop can be chosen such that immediately after an input step, the dynamics of feedback control is symmetric with respect to increments versus decrements. Finally, we study the dynamics of the output of the control loops and find conditions under which overshoots and undershoots of the output relative to the steady-state output occur when the models are stimulated with low-pass filtered steps. For small steps at the input, overshoots and undershoots of the output do not occur when the filtering in the control path is faster than the low-pass filtering at the input. For large steps at the input, however, results depend on the model, and for some of the models, multiple overshoots and undershoots can occur even with a fast control path. (shrink)

In this paper I show why Norbert Hoerster's plea for atheism is rather unconvincing.

Ai Ssu-ch'i is a little known but very important figure in the introduction of Marxism-Leninism into China. This first article provides a brief biography of Ai Ssu-ch'i as well as a detailed account of his activities as teacher, author and propagandist. Among his other services to the cause of Marxism-Leninism in China, one has to stress Ai Ssu-ch'i's systematic opposition to Yeh Ch'ing and to the non-Communist interpretation of Dr. Sun Yat-sen's Three Principles of the People. (cf.SST 10 (1970), 138–166.).

This article examines one of the most crucial yet often-overlooked links in global film processes: piracy. It does so within the context of a changing digital media environment that calls for a reassessment of key dimensions: networks, globalization, technology, space and the state. More specifically, it focuses on the operation of film piracy networks in Greater China that includes the Mainland, Hong Kong and Taiwan. By zooming in on `Greater China', this article presents empirical accounts of specific links and connections (...) on and between the intersecting distribution and piracy networks. In sum, distribution and piracy in China highlight some of the most interesting and intricate insights into issues of power, control, technology, network, speed, global-regional-national dynamics, subjectivities and reflexivity. Given the complexity of the issues, this study argues for a spatial, network and process-oriented theoretical framework. (shrink)

Liberal critics of plato's republic criticise him for ignoring the moral autonomy of persons, their right to form and to express their own moral ideas. It is argued that this criticism is superficial. Neither plato, nor his liberal critics, wish all moral views to be held and acted on; they both wish to set limits to what is acceptable. The true source of disagreement is over the scope of reason in human affairs; plato understands that narrowly; his liberal critics in (...) a broad, permissive, way. (shrink)

In 1961 the Centre for the Study of the History of Education at Ghent University, Belgium published the first issue of the multilingual journal _Paedagogica Historica: International Journal of the History of Education_. This book celebrates its fiftieth volume. In fourteen contributions written by different generations of historians of education, it demonstrates that in an era where the history of education at university level is at risk, both the journal and the discipline are pulsing, and alive and kicking. Was the (...) journal a trendsetter or a follower, and which position did it take with respect to the International Standing Conference for the History of Education? These are questions addressed in the first section of this book. In the second section, a number of articles show national and transnational developments of the history of education. In their diversity, they make clear how the national and the transnational together characterize the discipline. They show why journals in this domain should stimulate the development of broader concepts and theories in order to put national and regional cases in a broader scientific context and to make them attractive for international readership. In the last section authors turn their minds to the future of the history of education. They write about the shaping of new trends and about moving beyond borders, focusing on, among other things, the challenge of neurosciences and of digital humanities. This book was originally published as a special issue of _Paedagogica Historica_. (shrink)

In this paper I critically examine Peter Byrne's arguments against theological realism.