Optimized reprocessing of documents using stored processor state

Variable Data Printing (VDP) allows customised versions of material such as advertising flyers to be readily produced. However, VDP is often extremely demanding of computing resources because, even when much of the material stays invariant from one document instance to the next, it is often simpler to re-evaluate the page completely rather than identifying just the portions that vary. In this paper we explore, in an XML/XSLT/SVG workflow and in an editing context, the reduction of the processing burden that can be realised by selectively reprocessing only the variant parts of the document. We introduce a method of partial re-evaluation that relies on re-engineering an existing XSLT parser to handle, at each XML tree node, both the storage and restoration of state for the underlying document processing framework. Quantitative results are presented for the magnitude of the speed-ups that can be achieved. We also consider how changes made through an appearance-based interactive editing scheme for VDP documents can be automatically reflected in the document view via optimised XSLT re-evaluation of sub-trees that are affected either by the changed script or by altered data

Optimized reprocessing of documents using stored processor state

Variable Data Printing (VDP) allows customised versions of material such as advertising flyers to be readily produced. However, VDP is often extremely demanding of computing resources because, even when much of the material stays invariant from one document instance to the next, it is often simpler to re-evaluate the page completely rather than identifying just the portions that vary. In this paper we explore, in an XML/XSLT/SVG workflow and in an editing context, the reduction of the processing burden that can be realised by selectively reprocessing only the variant parts of the document. We introduce a method of partial re-evaluation that relies on re-engineering an existing XSLT parser to handle, at each XML tree node, both the storage and restoration of state for the underlying document processing framework. Quantitative results are presented for the magnitude of the speed-ups that can be achieved. We also consider how changes made through an appearance-based interactive editing scheme for VDP documents can be automatically reflected in the document view via optimised XSLT re-evaluation of sub-trees that are affected either by the changed script or by altered data

MODIS information, data and control system (MIDACS) operations concepts

The MODIS Information, Data, and Control System (MIDACS) Operations Concepts Document provides a basis for the mutual understanding between the users and the designers of the MIDACS, including the requirements, operating environment, external interfaces, and development plan. In defining the concepts and scope of the system, how the MIDACS will operate as an element of the Earth Observing System (EOS) within the EosDIS environment is described. This version follows an earlier release of a preliminary draft version. The individual operations concepts for planning and scheduling, control and monitoring, data acquisition and processing, calibration and validation, data archive and distribution, and user access do not yet fully represent the requirements of the data system needed to achieve the scientific objectives of the MODIS instruments and science teams. The teams are not yet formed; however, it is possible to develop the operations concepts based on the present concept of EosDIS, the level 1 and level 2 Functional Requirements Documents, and through interviews and meetings with key members of the scientific community. The operations concepts were exercised through the application of representative scenarios

Optimised editing of variable data documents via partial re-evaluation

With the advent of digital printing presses and the continued development of associated technologies, variable data printing (VDP) is becoming more and more common. VDP allows for a series of data instances to be bound to a single template document in order to produce a set of result document instances, each customized depending upon the data provided. As it gradually enters the mainstream of digital publishing there is a need for appropriate and powerful editing tools suitable for use by creative professionals. This thesis investigates the problem of representing variable data documents in an editable visual form, and focuses on the technical issues involved with supporting such an editing model. Using a document processing model where the document is produced from a data set and an appropriate programmatic transform, this thesis considers an interactive editor developed to allow visual manipulation of the result documents. It shows how the speed of the reprocessing necessary in such an interactive editing scenario can be increased by selectively re-evaluating only the required parts of the transformation, including how these pieces of the transformation can be identified and subsequently re-executed. The techniques described are demonstrated using a simplified document processing model that closely resembles variable data document frameworks. A workable editor is also presented that builds on this processing model and illustrates its advantages. Finally, an analysis of the performance of the proposed framework is undertaken including a comparison to a standard processing pipeline

Optimised editing of variable data documents via partial re-evaluation

With the advent of digital printing presses and the continued development of associated technologies, variable data printing (VDP) is becoming more and more common. VDP allows for a series of data instances to be bound to a single template document in order to produce a set of result document instances, each customized depending upon the data provided. As it gradually enters the mainstream of digital publishing there is a need for appropriate and powerful editing tools suitable for use by creative professionals. This thesis investigates the problem of representing variable data documents in an editable visual form, and focuses on the technical issues involved with supporting such an editing model. Using a document processing model where the document is produced from a data set and an appropriate programmatic transform, this thesis considers an interactive editor developed to allow visual manipulation of the result documents. It shows how the speed of the reprocessing necessary in such an interactive editing scenario can be increased by selectively re-evaluating only the required parts of the transformation, including how these pieces of the transformation can be identified and subsequently re-executed. The techniques described are demonstrated using a simplified document processing model that closely resembles variable data document frameworks. A workable editor is also presented that builds on this processing model and illustrates its advantages. Finally, an analysis of the performance of the proposed framework is undertaken including a comparison to a standard processing pipeline

CryoSat Ice Baseline-D validation and evolutions

The ESA Earth Explorer CryoSat-2 was launched on 8 April 2010 to monitor the precise changes in the thickness of terrestrial ice sheets and marine floating ice. To do that, CryoSat orbits the planet at an altitude of around 720 km with a retrograde orbit inclination of 92∘ and a quasi repeat cycle of 369 d (30 d subcycle). To reach the mission goals, the CryoSat products have to meet the highest quality standards to date, achieved through continual improvements of the operational processing chains. The new CryoSat Ice Baseline-D, in operation since 27 May 2019, represents a major processor upgrade with respect to the previous Ice Baseline-C. Over land ice the new Baseline-D provides better results with respect to the previous baseline when comparing the data to a reference elevation model over the Austfonna ice cap region, improving the ascending and descending crossover statistics from 1.9 to 0.1 m. The improved processing of the star tracker measurements implemented in Baseline-D has led to a reduction in the standard deviation of the point-to-point comparison with the previous star tracker processing method implemented in Baseline-C from 3.8 to 3.7 m. Over sea ice, Baseline-D improves the quality of the retrieved heights inside and at the boundaries of the synthetic aperture radar interferometric (SARIn or SIN) acquisition mask, removing the negative freeboard pattern which is beneficial not only for freeboard retrieval but also for any application that exploits the phase information from SARIn Level 1B (L1B) products. In addition, scatter comparisons with the Beaufort Gyre Exploration Project (BGEP; https://www.whoi.edu/beaufortgyre, last access: October 2019) and Operation IceBridge (OIB; Kurtz et al., 2013) in situ measurements confirm the improvements in the Baseline-D freeboard product quality. Relative to OIB, the Baseline-D freeboard mean bias is reduced by about 8 cm, which roughly corresponds to a 60 % decrease with respect to Baseline-C. The BGEP data indicate a similar tendency with a mean draft bias lowered from 0.85 to −0.14 m. For the two in situ datasets, the root mean square deviation (RMSD) is also well reduced from 14 to 11 cm for OIB and by a factor of 2 for the BGEP. Observations over inland waters show a slight increase in the percentage of good observations in Baseline-D, generally around 5 %–10 % for most lakes. This paper provides an overview of the new Level 1 and Level 2 (L2) CryoSat Ice Baseline-D evolutions and related data quality assessment, based on results obtained from analyzing the 6-month Baseline-D test dataset released to CryoSat expert users prior to the final transfer to operations

CryoSat Ice Baseline-D validation and evolutions

The ESA Earth Explorer CryoSat-2 was launched on 8 April 2010 to monitor the precise changes in the thickness of terrestrial ice sheets and marine floating ice. To do that, CryoSat orbits the planet at an altitude of around 720 km with a retrograde orbit inclination of 92∘ and a quasi repeat cycle of 369 d (30 d subcycle). To reach the mission goals, the CryoSat products have to meet the highest quality standards to date, achieved through continual improvements of the operational processing chains. The new CryoSat Ice Baseline-D, in operation since 27 May 2019, represents a major processor upgrade with respect to the previous Ice Baseline-C. Over land ice the new Baseline-D provides better results with respect to the previous baseline when comparing the data to a reference elevation model over the Austfonna ice cap region, improving the ascending and descending crossover statistics from 1.9 to 0.1 m. The improved processing of the star tracker measurements implemented in Baseline-D has led to a reduction in the standard deviation of the point-to-point comparison with the previous star tracker processing method implemented in Baseline-C from 3.8 to 3.7 m. Over sea ice, Baseline-D improves the quality of the retrieved heights inside and at the boundaries of the synthetic aperture radar interferometric (SARIn or SIN) acquisition mask, removing the negative freeboard pattern which is beneficial not only for freeboard retrieval but also for any application that exploits the phase information from SARIn Level 1B (L1B) products. In addition, scatter comparisons with the Beaufort Gyre Exploration Project (BGEP; https://www.whoi.edu/beaufortgyre, last access: October 2019) and Operation IceBridge (OIB; Kurtz et al., 2013) in situ measurements confirm the improvements in the Baseline-D freeboard product quality. Relative to OIB, the Baseline-D freeboard mean bias is reduced by about 8 cm, which roughly corresponds to a 60 % decrease with respect to Baseline-C. The BGEP data indicate a similar tendency with a mean draft bias lowered from 0.85 to −0.14 m. For the two in situ datasets, the root mean square deviation (RMSD) is also well reduced from 14 to 11 cm for OIB and by a factor of 2 for the BGEP. Observations over inland waters show a slight increase in the percentage of good observations in Baseline-D, generally around 5 %–10 % for most lakes. This paper provides an overview of the new Level 1 and Level 2 (L2) CryoSat Ice Baseline-D evolutions and related data quality assessment, based on results obtained from analyzing the 6-month Baseline-D test dataset released to CryoSat expert users prior to the final transfer to operations