2016-05 An Improved Pipeline for CPI Data

This report provides an update on a previous report, “An OpenAPI Pipeline for CPI Data”, which described the construction of an OpenAPI pipeline to produce a plot of CPI data. Two issues were identified with the original pipeline: the system requirements necessary to run the pipeline were significant; and the system requirements necessary just to run the OpenAPI glue system, the R package ‘conduit’, while much less, were still a potential obstacle to use of the pipeline by a lay audience. This report demonstrates solutions for both issues: a new “host” mechanism for OpenAPI modules to satisfy module system requirements; and an example of a user-friendly web front-end for running OpenAPI pipelines in ‘conduit’.

Paul Murrell

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2016-02 Debugging Display List Internals

This report documents the process of debugging a problem with the recording and replaying of R plots from one R session to another. The purpose of this report is to record the source of the problem, to record the solution to the problem, to explain some of the internal details of recorded R plots, and to demonstrate the ‘hexView’ package for exploring binary blobs.

Paul Murrell

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2016-01 OpenAPI version 0.3

The OpenAPI project aims to help people connect with data. OpenAPI is a software architecture for wrapping component pieces of data analysis – datasets, programming scripts, etc. – in reusable modules. These simple modules can be combined in pipelines which describe more complex data analysis workflows. Modules and pipelines are created in XML, and executed in software called a glue system. This report details the improvements made to the OpenAPI architecture between versions 0.1 and 0.3.

Ashley Noel Hinton and Paul Murrell

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2015-07 Recording and Replaying the Graphics Engine Display List

In the development version of R (to be R 3.3.0), it is possible again to save the result of recordPlot() from one R session and then load it and replay it, with replayPlot(), in a different R session. This recording and replaying of R plots across R sessions has also been made safer, with more warnings and errors in place to protect against incompatibilities between R versions, and it has been made better, with support for reloading packages along with a “recordedplot”, and with support for reproducing the ‘grid’ display list when redrawing a “recordedplot” that contains ‘grid’ output.

Paul Murrell, Jeroen Ooms, JJ Allaire

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2015-06 A ‘safemode’ Package for R

The ‘safemode’ package provides a safemode() function that creates a “safe mode” session in R. In “safe mode”, all symbols have an “age” (a last-modified time stamp) and a set of dependent symbols, and a warning is issued whenever a symbol is used in an expression and its age exceeds the age of any of its dependents (i.e., there is warning whenever a “stale” symbol is used in an expression).

Paul Murrell

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2015-05 Generating SVG for Web Pages with the gridSVG Package

This document describes several different techniques for including SVG images within a web page and points out the important SVG attributes that control the final appearance of the SVG image within the web page. The document then describes how to control those attributes when generating SVG images with the ‘gridSVG’ package for R.

Paul Murrell

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2015-04 Helping people to connect with data

This articles explores the problem of helping people connect with data. In the first section I examine the importance of connecting people with data, and look at why people are not fully connected with data at present. In the second section I consider how software can contribute to solving this problem, and examine some software examples which may contribute to the solution. In the third section I give details of how the OpenAPI project intends to solve the problem.

Ashley Noel Hinton

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2015-03 Uncertainty Evaluation of Computer Simulation Models (Draft Report)

Deterministic agricultural and agro-ecosystem systems models have an important role worldwide. Although these models are mathematically deterministic, there are many possible sources of uncertainty that can propagate through the model. The development of tools to evaluate uncertainty in deterministic models is an active area of research. There are a number of options for model uncertainty evaluation that have been discussed in the literature. The objectives of this review paper are threefold: 1. To describe a formalised state-space framework within which to describe the types and sources of uncertainty that arise in computer simulation models. 2. To provide a framework to carry out a robust uncertainty evaluation of a computer simulation model. 3. To summarise a selection of relevant sampling and analysis techniques for the uncertainty evaluation of computer simulation models.

Esther Meenken, Chris Triggs et al.

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