22,266 research outputs found
Matchings, coverings, and Castelnuovo-Mumford regularity
We show that the co-chordal cover number of a graph G gives an upper bound
for the Castelnuovo-Mumford regularity of the associated edge ideal. Several
known combinatorial upper bounds of regularity for edge ideals are then easy
consequences of covering results from graph theory, and we derive new upper
bounds by looking at additional covering results.Comment: 12 pages; v4 has minor changes for publicatio
Vertex decomposable graphs and obstructions to shellability
Inspired by several recent papers on the edge ideal of a graph G, we study
the equivalent notion of the independence complex of G. Using the tool of
vertex decomposability from geometric combinatorics, we show that 5-chordal
graphs with no chordless 4-cycles are shellable and sequentially
Cohen-Macaulay. We use this result to characterize the obstructions to
shellability in flag complexes, extending work of Billera, Myers, and Wachs. We
also show how vertex decomposability may be used to show that certain graph
constructions preserve shellability.Comment: 13 pages, 3 figures. v2: Improved exposition, added Section 5.2 and
additional references. v3: minor corrections for publicatio
Hitsville UK: punk in the faraway towns
This was an exhibition of UK punk rock record sleeve design across the period 1976-1984, and consisted of a wide range of record sleeves grouped by punk and post punk sub-genres, and a large format exhibition timeline mapping the chronology and geography of the graphic evolution of punk within this timeframe, using seven inch single sleeves as a representative case study for analysis. This was accompanied by a range of interactive and sound installations allowing users to view the production details of each sleeve and to hear the music on the records.
The research consisted of a detailed analysis of ‘quintessentially punk artefacts’, the seven-inch ‘picture’ record sleeves associated with UK Punk. New perspectives on their production and their graphic characteristics including any recurring visual tropes or pictorial devices and the use of a DIY aesthetic were created.
The period covered was c.1976-1984. Two important aspects of the research methodology were, firstly, to consider the graphic design of the record sleeves through the prism of the complex sub-cultural codes that were characteristic of UK Punk at this period and, secondly, to view these graphic artefacts as indissoluble from the UK Punk’s musical language. An additional feature of the research was the mapping of the diaspora of UK Punk form London, Manchester and other large cities to ‘the faraway towns’ by means of a visual matrix that demonstrated a widening geographic spread of seven-inch single production during much of period.
The exhibitions which were slightly different in each venue, celebrated the wide range of graphic approaches adopted and redressed the balance of recent punk accounts which focus on the short-lived activities of UK Punk’s early years.
Together with the visual matrix and real-size reproductions of a wide range of graphic material, the research resulted in an exhibition catalogue package that included three reversible posters, and an interactive web-based resource which links the seven-inch sleeve to its key musical track
We’re So Bored With London, Wayne Daly in conversation with Russell Bestley, Parts 1 & 2
Interview discussion with Wayne Daly on the subject of UK punk singles
ADLib: An Arduino Communication Framework for Ambient Displays
As computers become more and more a part of our everyday lives, the need to change the way in which people interact with them is also evolving. Ambient displays provide an effective way to move computers away from our main focus and into the periphery.
ADLib is a small communication framework that aims to simplify the construction of ambient displays built using the Arduino prototyping platform. The ADLib framework provides an easy-to-use library for communicating with an Arduino, allowing the user to focus on the construction and development of the display.
The framework consists of three main components: A protocol for encoding information to be sent from a host computer to the Arduino An Arduino library for receiving and parsing incoming data A desktop application for sending data to the Arduin
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