Basic principles of SSM modelling: an examination of CATWOE from a soft perspective

This paper examines the SSM technique CATWOE, which focuses on defining necessary elements that together constitute a human activity system from a certain perspective. Despite its recognition within the literature and its numerous uses, there are few studies on how the technique can be improved. This research reflects on each of the elements both from a theoretical and a practical perspective. Findings point to the fact that some of the terms have a meaning in everyday language that differs from its definition within CATWOE. Other concepts are not well-defined. This is unfortunate and may both lead to misunderstandings and limit analysis. The paper points to a number of ways in which the use of CATWOE can be developed in order to further support the process of eliciting novel ideas for future actions. Hence, the overall conclusion is that the elements need to be rethought and some of them renamed

Wavefront sensing with a brightest pixel selection algorithm

Astronomical adaptive optics systems with open-loop deformable mirror control have recently come on-line. In these systems, the deformable mirror surface is not included in the wavefront sensor paths, and so changes made to the deformable mirror are not fed back to the wavefront sensors. This gives rise to all sorts of linearity and control issues mainly centred on one question: Has the mirror taken the shape requested? Non-linearities in wavefront measurement and in the deformable mirror shape can lead to significant deviations in mirror shape from the requested shape. Here, wavefront sensor measurements made using a brightest pixel selection method are discussed along with the implications that this has for open-loop AO systems. Discussion includes elongated laser guide star spots and also computational efficiency.Comment: 10 pages, 12 figures, accepted by MNRA

Understanding the relationships between fields of research

This paper suggests how mutual understanding and respect may be fostered between very different fields of research, which seem to have little in common. The meaning and value of each field, and the relationships among them, are revealed using Dooyeweerd's aspects. Dooyeweerd is rare among philosophers in having made an intensive study of the diversity and coherence of meaningfulness. In this way, researchers in one field can more fully understand the ways in which findings or research in other fields are meaningful. Dooyeweerd's inter-aspect relationships help us understand the types of relationship a field might have with others

Ground-layer adaptive-optics system modelling for the ChineseLarge Optical/Infrared Telescope

The Chinese Large Optical/Infrared Telescope is currently undergoing design studies. A ground-layer adaptive-optics system (GLAO) has been proposed, with a 14 -arcmin field of view (FOV) and moderate adaptive-optics correction using a deformable secondary mirror, several laser guide stars (LGS) and wavefront sensors. Due to its large FOV and relatively complex structure, some important problems should be analysed to aid budget considerations for the whole telescope. In this paper, we propose a FOV-related evaluation factor to describe the GLAO performance and use an end-to-end Monte Carlo simulation to test its performance under different configurations. To accelerate the parameter space exploration speed, we split the parameter space of the GLAO system and apply a bottom-up search procedure for parameter selection. We also propose a simplified turbulence geometric model to evaluate the GLAO performance with different turbulence-profile-related parameters. With the above methods, we analyse the required number of deformable mirror (DM) actuators, the number, position and magnitude of LGS and explore the DM tilt-conjugation problem for this GLAO system