Stacked graphs using matplotlib « ActiveState Code     Stacked Graphs – Geometry & Aesthetics Abstract — In February 2008, the New York Times published an unusual chart of box office revenues for 7500 movies over 21 years. The chart was based on a similar visualization, developed by the first author, that displayed trends in music listening. This paper describes the design decisions and algorithms behind these graphics, and discusses the reaction on the Web. We suggest that this type of complex layered graph is effective for displaying large data sets to a mass audience. We provide a mathematical analysis of how this layered graph relates to traditional stacked graphs and to techniques such as ThemeRiver, showing how each method is optimizing a different “energy function”. Finally, we discuss techniques for coloring and ordering the layers of such graphs. Throughout the paper, we emphasize the interplay between considerations of aesthetics and legibility.     http://www.leebyron.com/else/streamgraph/download.php?file=s...     tags: streamgraph visualization viz filetype_pdf media_document Reconsidering Custom Memory Allocation     Despite the widespread belief that custom allocators improve performance, we come to a different conclusion. In this paper, we examine eight benchmarks using custom memory allocators, including the Apache web server and several applications from the SPECint2000 benchmark suite. We find that the Lea allocator is as fast as or even faster than most custom allocators. The exceptions are region-based allocators, which often outperform generalpurpose allocation     http://www.cs.umass.edu/~emery/pubs/berger-oopsla2002.pdf     tags: arena c_ malloc tcmalloc memory allocator filetype_pdf media_document Dual Pivot Quicksort     Sorting data is one of the most fundamental problems in Computer Science, especially if the arranging objects are primitive ones, such as integers, bytes, floats, etc. Since sorting methods play an important role in the operation of computers and other data processing systems, there has been an interest in seeking new algorithms better than the existing ones. We compare sorting methods by the number of the most "expensive" operations, which influence on effectiveness of the sorting techniques, — comparisons and swaps. Quicksort algorithm is an effective and wide-spread sorting procedure with C*n *ln(n) operations, where n is the size of the arranged array. The problem is to find an algorithm with the least coefficient C. There were many attempts to improve the classical variant of the Quicksort algorithm     http://iaroslavski.narod.ru/quicksort/DualPivotQuicksort.pdf     tags: sort quicksort filetype_pdf media_document Hotmap: Paying Attention to Geographical Attention     Understanding how people use online maps allows data acquisition teams to concentrate their efforts on the portions of the map that are most seen by users. Online maps represent vast databases, and so it is insufficient to simply look at a list of the most-accessed URLs. Hotmap takes advantage of the design of a mapping system’s imagery pyramid to superpose a heatmap of the log files over the original maps. Users’ behavior within the system can be observed and interpreted. This paper discusses the imagery acquisition task that motivated Hotmap, and presents several examples of information that Hotmap makes visible. We discuss the design choices behind Hotmap, including logarithmic color schemes; low-saturation background images; and tuning images to explore both infrequently-viewed and frequently-viewed spaces.     http://research.microsoft.com/pubs/69446/fisher_infovis_hotm...     tags: heatmap hotmap microsoft map filetype_pdf media_document Splay trees in practice for large text collections     http://goanna.cs.rmit.edu.au/~naskitis/Nikolas_Askitis_PhD_T...     tags: burst trie hat btree sleepycat berkeleydb hat-trie burst-trie judy-trie filetype_pdf media_document What Every Programmer Should Know About Memory     As CPU cores become both faster and more numerous, the limiting factor for most programs is now, and will be for some time, memory access. Hardware designers have come up with ever more sophisticated memory handling and acceleration techniques–such as CPU caches–but these cannot work optimally without some help from the programmer. Unfortunately, neither the structure nor the cost of using the memory subsystem of a computer or the caches on CPUs is well understood by most programmers. This paper explains the structure of memory subsys- tems in use on modern commodity hardware, illustrating why CPU caches were developed, how they work, and what programs should do to achieve optimal performance by utilizing them.     http://people.redhat.com/drepper/cpumemory.pdf     tags: ram memory cpu numa l1 l2 l3 cache filetype_pdf media_document Selmer Bringsjord cv     Selmer Bringsjord Professor of Philosophy, Logic, and Cognitive Science Professor of Computer Science Director, Rensselaer AI & Reasoning (RAIR) Laboratory Department of Cognitive Science (Chair) Department of Computer Science Rensselaer Polytechnic Institute (RPI)     http://kryten.mm.rpi.edu/scb_vitae_091808.pdf     tags: cv mind reason logic ai filetype_pdf media_document A Measure of Deviations from Poisson     Low frequency words tend to be rich in content, and vice versa. But not all equally frequent words are equally mean!ngful. We will use inverse document frequency (IDF), a quantity borrowed from Information Retrieval, to distinguish words like somewhat and boycott. Both somewhat and boycott appeared approximately 1000 times in a corpus of 1989 Associated Press articles, but boycott is a better keyword because its IDF is farther from what would be expected by chance (Poisson).     http://www.aclweb.org/anthology-new/W/W95/W95-0110.pdf     tags: ir tfidf search filetype_pdf media_document ROTTEN APPLES: AN INVESTIGATION OF THE PREVALENCE AND PREDIC...     http://www.educationnext.org/unabridged/20041/68.pdf     tags: levitt filetype_pdf media_document Slashdot: News for nerds, stuff that matters     MI LEPOST GCC: machine learning based research compiler     http://gcc-ici.sourceforge.net/papers/fmtp2008.pdf     tags: gcc g_ optimization filetype_pdf media_document Lucene and Juru at Trec 2007: 1-Million Queries Track     http://trec.nist.gov/pubs/trec16/papers/ibm-haifa.mq.final.p...     tags: lucene trec filetype_pdf media_document Stock Options and the Lying Liars Who Don’t Want to Expens...     http://www.cfapubs.org/faj/issues/v60n4/pdf/f0600009a.pdf     tags: stock stock-options filetype_pdf media_document The Freshness of Web search engines’ databases     http://eprints.rclis.org/archive/00004619/01/JIS_preprint.pd...     tags: search google filetype_pdf media_document The winner’s curse, reserve prices,and endogenous entry: e...     http://www.rje.org/abstracts/abstracts/2003/rje.sum03.Bajari...     tags: psychology ebay auction filetype_pdf media_document