Gradual structuring: Evolving the spreadsheet paradigm for expressiveness and learnability

© 2016 IEEE. Spreadsheets are arguably the most used form of programming and are frequently used in higher education to teach fundamental concepts about computation. Their success has shown that they are simple enough for a huge number of end users to learn and use. This is in contrast to traditional programming languages and the high dropout rate from introductory programming and computer science. However in comparison to traditional programming languages and structured modelling, spreadsheets are not expressive, placing a limit on the levels of computational thinking that can be taught using the spreadsheet paradigm. This limitation is imposed by the lack of programming language features and abstractions in the paradigm. Furthermore, more advanced spreadsheet features (e.g. array formulae, lookup formulae, R1C1 syntax) can be difficult to learn and use. This paper discusses the idea of adding language features to spreadsheets, enabling the gradual structuring of free-form spreadsheets to more structured models. We propose that this concept is termed Gradual Structuring, and is analogous to the programming language concept of gradual typing. In this analogy, spreadsheets take the place of dynamic programming and structured modelling of static programming. In programming languages, gradual typing allows dynamic programming to be mixed with static programming. It is our contention that dynamic programming is more learnable while static programming is more expressive and abstract. Gradual typing could be used to mitigate the issues in the teaching of traditional programming. Likewise Gradual Structuring can mitigate the conceptual limits that can be taught using current spreadsheets. The key language feature required to enable Gradual Structuring is the ability to logically group cells together so that a single formula can be applied to the grouped cells. This concept, termed cell grouping diminishes and can even eliminate the need for the ubiquitous and error-prone use of copy-pasted in spreadsheets. Moreover, it makes the structure present in spreadsheet models explicit. Cell grouping requires a cascade of other new languages features. Namely a more expressive referencing style, which in turned requires enabling labels to be moved to the row and column headers, and the hierarchical structuring of these headers. Respectively these language features are termed enhanced referencing and semantic axes. The ongoing research focusses on the usability and learnability of these language features. Spreadsheet applications exist that contain aspects of the features mentioned. However these applications do not enable Gradual Structuring and have taken a mainly technical, not human behavioural, approach to evolving the spreadsheet

The Lish: a data model to support analysis by end user programmers

For end user programmers needing to carry out data analysis, the spreadsheet is an attractive choice, but has little safety net against user errors. Reducing these errors is an active research area, but one aspect rather little investigated is the role played by the underlying data model: the grid of cells. I am working on an alternative model, the “lish”, based on nested lists of cells. Its theoretical advantages include fewer and more concise formulae, and easier updates to the structure. A user study is in preparation to assess its practical utility

Structuring Spreadsheets with the “Lish” Data Model

A spreadsheet is remarkably flexible in representing various forms of structured data, but the individual cells have no knowledge of the larger structures of which they may form a part. This can hamper comprehension and increase formula replication, increasing the risk of error on both scores. We explore a novel data model (called the “lish”) that could form an alternative to the traditional grid in a spreadsheet-like environment. Its aim is to capture some of these higher structures while preserving the simplicity that makes a spreadsheet so attractive. It is based on cells organised into nested lists, in each of which the user may optionally employ a template to prototype repeating structures. These template elements can be likened to the marginal “cells” in the borders of a traditional worksheet, but are proper members of the sheet and may themselves contain internal structure. A small demonstration application shows the “lish” in operation

Integrating multi-way data-flow constraint systems in spreadsheets

Graphical user interfaces (GUIs) can be found in almost all aspects of our lives. We take a particular interest in spreadsheets in thesis, as they are an essential tool in many professions. Microsoft Excel is a prevalent spreadsheet software widely used across industries; it is frequently used to fill out various forms. However, maintaining dependencies between variables can be difficult to ensure and prone to bugs, especially as the size of the project increases. Our approach is to introduce some structure to Excel, and we have thus created a tool, HDTables, to address the problem of maintaining dependencies between variables. HDTables is an Excel add-in created using HotDrink, a JavaScript library that uses multi-way data-flow constraint systems to model GUIs, in combination with the visual programming environment Blockly. The tool is aimed at end-users with no programming background and allows them to create variables and constraints to explicitly define the data-flow between cells in Excel.Masteroppgave i Programutvikling samarbeid med HVLPROG399MAMN-PRO

Initial Conceptions in the Statistical Reasoning and Modeling Processes in Engineering Students

The cognitive view in educational psychology is considered one of the traditional perspectives for psychologists, who recognize that students may have different but identifiable conceptions of learning. The work aimed to compare initial conceptions of statistical modeling processes and levels of statistical reasoning in engineering students. The research had a qualitative approach with a multiple-case design. As a source of data collection, a questionnaire was designed and applied to 38 students taking the subject Probability and Statistics. The results and data analysis showed that none of the participants went through all the phases of statistical modeling, evidencing a low ability to establish relationships in the data and interconnect statistical concepts. Consequently, the students failed to reach the maximum level of statistical reasoning. The participants also identified difficulties in establishing coherent interpretations when making representations of statistical models such as frequency tables, graphs and measures of central tendency. Therefore, there is a need to continue developing research that provides theoretical foundations for the characterization of the modeling and statistical reasoning processes to improve the learning of statistics and probability in university students

An overview of decision table literature 1982-1995.

This report gives an overview of the literature on decision tables over the past 15 years. As much as possible, for each reference, an author supplied abstract, a number of keywords and a classification are provided. In some cases own comments are added. The purpose of these comments is to show where, how and why decision tables are used. The literature is classified according to application area, theoretical versus practical character, year of publication, country or origin (not necessarily country of publication) and the language of the document. After a description of the scope of the interview, classification results and the classification by topic are presented. The main body of the paper is the ordered list of publications with abstract, classification and comments.

User driven modelling: Visualisation and systematic interaction for end-user programming with tree-based structures

This thesis addresses certain problems encountered by teams of engineers when modelling complex structures and processes subject to cost and other resource constraints. The cost of a structure or process may be ‘read off’ its specifying model, but the language in which the model is expressed (e.g. CAD) and the language in which resources may be modelled (e.g. spreadsheets) are not naturally compatible. This thesis demonstrates that a number of intermediate steps may be introduced which enable both meaningful translation from one conceptual view to another as well as meaningful collaboration between team members. The work adopts a diagrammatic modelling approach as a natural one in an engineering context when seeking to establish a shared understanding of problems.Thus, the research question to be answered in this thesis is: ‘To what extent is it possible to improve user-driven software development through interaction with diagrams and without requiring users to learn particular computer languages?’ The goal of the research is to improve collaborative software development through interaction with diagrams, thereby minimising the need for end-users to code directly. To achieve this aim a combination of the paradigms of End-User Programming, Process and Product Modelling and Decision Support, and Semantic Web are exploited and a methodology of User Driven Modelling and Programming (UDM/P) is developed, implemented, and tested as a means of demonstrating the efficacy of diagrammatic modelling.In greater detail, the research seeks to show that diagrammatic modelling eases problems of maintenance, extensibility, ease of use, and sharing of information. The methodology presented here to achieve this involves a three step translation from a visualised ontology, through a modelling tool, to output to interactive visualisations. An analysis of users groups them into categories of system creator, model builder, and model user. This categorisation corresponds well with the three-step translation process where users develop the ontology, modelling tool, and visualisations for their problem.This research establishes and exemplifies a novel paradigm of collaborative end-user programming by domain experts. The end-user programmers can use a visual interface where the visualisation of the software exactly matches the structure of the software itself, making translation between user and computer, and vice versa, much more direct and practical. The visualisation is based on an ontology that provides a representation of the software as a tree. The solution is based on translation from a source tree to a result tree, and visualisation of both. The result tree shows a structured representation of the model with a full visualisation of all parts that leads to the computed result.In conclusion, it is claimed that this direct representation of the structure enables an understanding of the program as an ontology and model that is then visualised, resulting in a more transparent shared understanding by all users. It is further argued that our diagrammatic modelling paradigm consequently eases problems of maintenance, extensibility, ease of use, and sharing of information. This method is applicable to any problem that lends itself to representation as a tree. This is considered a limitation of the method to be addressed in a future project