John M. Boyer

Stop Minding Your P's and Q's: Implementing a Fast and Simple DFS-based Planarity Testing and Embedding Algorithm

In this paper we give a new description of the planarity testing and embedding algorithm presented by Boyer and Myrvold [2], providing, in our opinion, new insights on the combinatorial foundations of the algorithm. Especially, we give a detailed illustration of a fundamental phase of the algorithm, called walk-up, which was only succinctly illustrated in [2]. Also, we present an implementation of the algorithm and extensively test its efficiency against the most popular implementations of planarity testing algorithms. Further, as a side effect of the test activity, we propose a general overview of the state of the art (restricted to efficiency issues) of the planarity testing and embedding field.

A REST protocol and composite format for interactive web documents

Documents allow end-users to encapsulate information related to a collaborative business process into a package that can be saved, emailed, digitally signed, and used as the basis of interaction in an activity or an ad hoc workflow. While documents are used incidentally today in web applications, for example in HTML presentations of content stored otherwise in back-end systems, they are not yet the central artifact for developers of dynamic, data intensive web applications. This paper unifies the storage and management of the various artifacts of web applications into an Interactive Web Document (IWD). Data content, presentation, behavior, attachments, and digital signatures collected throughout the business process are unified into a single composite web resource. We describe a REST-based protocol for interacting with IWDs and a standards-based approach to packaging their multiple constituent artifacts into IWD archives based on the Open Document Format standard.

Interactive Web Documents

Documents allow end-users to encapsulate information related to a collaborative business process into a package that can be saved, emailed, digitally signed, and used as the basis for interaction in an activity or an ad hoc workflow. While documents are used incidentally today in web applications, for example in HTML presentations of content stored otherwise in back-end systems, they are not yet the central artifact for developers of dynamic, data intensive web applications. This paper unifies the storage and management of the various artifacts of web applications into an Interactive Web Document (IWD). Data, presentation, behavior, attachments, and digital signatures collected throughout the business process are unified into a single composite web resource. We describe a standards-based approach to packaging multiple resources into IWD archives based on the Open Document Format, a REST-based protocol for interacting with IWDs, and an extensible interaction controller architecture.

Additional PC-Tree planarity conditions

Recent research efforts have produced new algorithms for solving planarity-related problems. One such method performs vertex addition using the PC-tree data structure, which is similar to but simpler than the well-known PQ-tree. For each vertex, the PC-tree is first checked to see if the new vertex can be added without violating certain planarity conditions; if the conditions hold, the PC-tree is adjusted to add the new vertex and processing continues. The full set of planarity conditions are required for a PC-tree planarity tester to report only planar graphs as planar. This paper provides further analyses and new planarity conditions needed to produce a correct planarity algorithm with a PC-tree.

Lempel, Even, and Cederbaum Planarity Method

We present a simple pedagogical graph theoretical description of Lempel, Even, and Cederbaum (LEC) planarity method based on concepts due to Thomas. A linear-time implementation of LEC method using the PC-tree data structure of Shih and Hsu is provided and described in details. We report on an experimental study involving this implementation and other available linear-time implementations of planarity algorithms.

Subgraph Homeomorphism via the Edge Addition Planarity Algorithm

This paper extends the edge addition planarity algorithm from Boyer and Myrvold to provide a new way of solving the subgraph homeomorphism problem for K2,3, K4, and K3,3. These extensions derive much of their behavior and correctness from the edge addition planarity algorithm, providing an alternative perspective on these subgraph homeomorphism problems based on affinity with planarity rather than triconnectivity. Reference implementations of these algorithms have been made available in an open source project (http://code.google.com/p/planarity).

Enriching the interactive user experience of open document format

The typical user experience of office documents is geared to the passive recording of user content creation. In this paper, we describe how to provide more active content within such documents based on elaborating the integration between Open Document Format (ODF) and the W3C standard for rich interactivity and data management in web pages (XForms). This includes assignment of more comprehensive behaviors to single form controls, better control over collections of form controls, readonly and conditional sections of mixed content and form controls, and dynamically repeated sections automatically responsive to data changes, including data obtained from web services invoked during user interaction with the document.