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In situ satellite exploration of the lower thermosphere–ionosphere system (LTI) as anticipated in the recent Daedalus mission proposal to ESA will be essential to advance the understanding of the interface between the Earth's atmosphere and its space environment. To address physical processes also below perigee, in situ measurements are to be extrapolated using models of the LTI. Motivated by the need for assessing how cost-critical mission elements such as perigee and apogee distances as well as the number of spacecraft affect the accuracy of scientific inference in the LTI, the Daedalus Ionospheric Profile Continuation (DIPCont) project is concerned with the attainable quality of in situ measurement extrapolation for different mission parameters and configurations. This report introduces the methodological framework of the DIPCont approach. Once an LTI model is chosen, ensembles of model parameters are created by means of Monte Carlo simulations using synthetic measurements based on model predictions and relative uncertainties as specified in the Daedalus Report for Assessment. The parameter ensembles give rise to ensembles of model altitude profiles for LTI variables of interest. Extrapolation quality is quantified by statistics derived from the altitude profile ensembles. The vertical extent of meaningful profile continuation is captured by the concept of extrapolation horizons defined as the boundaries of regions where the deviations remain below a prescribed error threshold. To demonstrate the methodology, the initial version of the DIPCont package presented in this paper contains a simplified LTI model with a small number of parameters. As a major source of variability, the pronounced change in temperature across the LTI is captured by self-consistent non-isothermal neutral-density and electron density profiles, constructed from scale height profiles that increase linearly with altitude. The resulting extrapolation horizons are presented for dual-satellite measurements at different inter-spacecraft distances but also for the single-satellite case to compare the two basic mission scenarios under consideration. DIPCont models and procedures are implemented in a collection of Python modules and Jupyter notebooks supplementing this report. [ABSTRACT FROM AUTHOR] more...

The Daedalus Ionospheric Profile Continuation (DIPCont) project is concerned with the question how in situ measurements in the lower thermosphere and ionosphere (LTI) can be extrapolated using parametric models of observables and derived variables. To reflect the pronounced change of temperature across the LTI, non-isothermal models for neutral density and also electron density are constructed from scale height profiles that increase linearly with altitude. Ensembles of model parameters are created by means of Monte Carlo simulations using synthetic measurements based on model predictions and relative uncertainties as specified in the Daedalus Report for Assessment. The parameter ensembles give rise to ensembles of model altitude profiles for LTI variables of interest. Extrapolation quality is quantified by statistics derived from the altitude profile ensembles. The vertical extent of meaningful profile continuation is captured by the concept of extrapolation horizons defined as the boundaries of regions where the deviations remain below a prescribed error threshold. The methodology allows for assessing how cost-critical elements of the Daedalus mission proposal such as perigee and apogee distances as major factors controling the necessary amount of propellant and radiation shielding, respectively, affect the accuracy of scientific inference in the LTI. First results are presented for dual-satellite measurements at different inter-spacecraft distances but also for the single-satellite case to compare the two basic mission scenarios under consideration. DIPCont models and procedures are implemented in a collection of Python modules and Jupyter notebooks supplementing this report. [ABSTRACT FROM AUTHOR] more...

A key factor that can dramatically reduce the search space during constraint solving is the criterion under which the variable to be instantiated next is selected. For this purpose numerous heuristics have been proposed. Some of the best of such heuristics exploit information about failures gathered throughout search and recorded in the form of constraint weights, while others measure the importance of variable assignments in reducing the search space. In this work we experimentally evaluate the most recent and powerful variable ordering heuristics, and new variants of them, over a wide range of benchmarks. Results demonstrate that heuristics based on failures are in general more efficient. Based on this, we then derive new revision ordering heuristics that exploit recorded failures to efficiently order the propagation list when arc consistency is maintained during search. Interestingly, in addition to reducing the number of constraint checks and list operations, these heuristics are also able to cut down the size of the explored search tree. [ABSTRACT FROM AUTHOR] more...

Mind Mapping is an important technique that improves the way you takes notes, and enhances your creative problem solving. By using Mind Maps, you can quickly identify and understand the structure of a subject and the way that pieces of information fit together, as well as recording the raw facts contained in normal notes. It can also be used as complementary tools for knowledge construction and sharing. Their suitability as a pedagogical tool for education, e-learning and training, increases their importance. Also, in a world of information overload and businesses struggling to keep up with the place of change, knowledge workers need effective tools to organize, analyze, brainstorm and collaborate on ideas. In resent years, a wide variety of mind mapping software tools have been developed. An often question that comes up, due to this plethora of software tools, is "which is the best mind mapping software?" Anyone who gives you an immediate answer either knows you and your mind mapping activities very well or their answer in not worth a lot. The "best" depends so much on how you use mind maps. In this paper we are trying to investigate different user profiles and to identify various axes for comparison among mind mapping tools that are suitable for a specific user profile, describe each axis and then analyze each tool. [ABSTRACT FROM AUTHOR] more...