Genetic programming for the minimum time swing up and balance control acrobot problem

This work describes how genetic programming is applied to evolving controllers for the minimum time swing up and inverted balance tasks of the continuous state and action: limited torque acrobot. The best swing-up controller is able to swing the acrobot up to a position very close to the inverted ‘handstand’ position in a very short time, shorter than that of Coulom (2004), who applied the same constraints on the applied torque values, and to take only slightly longer than the approach by Lai et al. (2009) where far larger torque values were allowed. The best balance controller is able to balance the acrobot in the inverted position when starting from the balance position for the length of time used in the fitness function in all runs; furthermore, 47 out of 50 of the runs evolve controllers able to maintain the balance position for an extended period, an improvement on the balance controllers generated by Dracopoulos and Nichols (2012), which this paper is extended from. The most successful balance controller is also able to balance the acrobot when starting from a small offset from the balance position for this extended period.

Parallel languages in the history of language ideology in Norway and the lesson for Nordic higher education

This chapter compares recent policy on the use of English and Norwegian in Higher Education with earlier policies on the relationship between the two standard varieties of Norwegian, and it charts how and why English became a policy issue in Norway. Based on the experience of over a century of language planning, a highly interventionist approach is today being avoided and language policies in the universities of Norway seek to nurture a situation where English and Norwegian may be used productively side-by-side. However, there remain serious practical challenges to be overcome. This paper also builds on a previous analysis (Linn 2010b) of the metalanguage of Nordic language policy and seeks to clarify the use of the term ‘parallelingualism’.