title: Influence of “defects” on sorted bedform dynamics

authors: Huntley, David A.

subjects: sorted bedforms

abstract: Bedforms with plan-view patterns consisting of long crests interrupted by defects occur ubiquitously in subaqueous and subaerial environments where they strongly influence flows and sediment transport. We explore how such patterns adjust to changes in the external forcing. We utilize a numerical model of a wide-spread, large-scale seabed pattern, ‘sorted bedforms,’ examining their response to changes in wave forcing. Numerical experiments show that the pattern adjustment progresses through two stages characterized by defect propagation and defect creation, respectively, and that the rates of the initial stage, and therefore overall pattern adjustment, are determined by the initial defect density. All characteristics of the sorted bedforms are similarly influenced by the presence of defects. Although the processes of growth are likely to be different for other types of bedforms, it is reasonable to expect they will be similarly influenced by defects in pre-existing patterns.

text: Influence of “defects” on sorted bedform dynamics Bedforms with plan-view patterns consisting of long crests interrupted by defects occur ubiquitously in subaqueous and subaerial environments where they strongly influence flows and sediment transport. We explore how such patterns adjust to changes in the external forcing. We utilize a numerical model of a wide-spread, large-scale seabed pattern, ‘sorted bedforms,’ examining their response to changes in wave forcing. Numerical experiments show that the pattern adjustment progresses through two stages characterized by defect propagation and defect creation, respectively, and that the rates of the initial stage, and therefore overall pattern adjustment, are determined by the initial defect density. All characteristics of the sorted bedforms are similarly influenced by the presence of defects. Although the processes of growth are likely to be different for other types of bedforms, it is reasonable to expect they will be similarly influenced by defects in pre-existing patterns.

year: 2008

title: Data structures for Z testing tools.

authors: Utting, Mark

abstract: This paper describes some of the difficulties and challenges that arise during the design of tools for validating Z specifications by testing and animation. We address three issues: handling undefined terms, simplification versus enumeration, and the representation of sets, and show how each issue has been handled in the Jaza tool.
Finally, we report on a brief experimental comparison of existing Z animators and conclude that while the state of the art is improving, more work is needed to ensure that the tools are robust and respect the Z semantics.

text: Data structures for Z testing tools. This paper describes some of the difficulties and challenges that arise during the design of tools for validating Z specifications by testing and animation. We address three issues: handling undefined terms, simplification versus enumeration, and the representation of sets, and show how each issue has been handled in the Jaza tool.
Finally, we report on a brief experimental comparison of existing Z animators and conclude that while the state of the art is improving, more work is needed to ensure that the tools are robust and respect the Z semantics.

year: 2001-06-01

title: Lake weed and the Rotorua Te Arawa Lakes then and now

authors: Burton, Tracy

abstract: This afternoon we will be looking beneath the surface of the Rotorua
Te Arawa lakes at the submerged aquatic plants that grow within them – the good the bad and the ugly. We will have a look at the special native aquatic plants that occur naturally in the lakes, familiarise ourselves with the weed species that have invaded them and look at how these weeds have (and are) changed the natural condition of the lakes. We will also look at how submerged plants are being used to report on the condition of our lakes and what these plant communities can tell us about the state of the lakes yesterday and today.

text: Lake weed and the Rotorua Te Arawa Lakes then and now This afternoon we will be looking beneath the surface of the Rotorua
Te Arawa lakes at the submerged aquatic plants that grow within them – the good the bad and the ugly. We will have a look at the special native aquatic plants that occur naturally in the lakes, familiarise ourselves with the weed species that have invaded them and look at how these weeds have (and are) changed the natural condition of the lakes. We will also look at how submerged plants are being used to report on the condition of our lakes and what these plant communities can tell us about the state of the lakes yesterday and today.

year: 2017