Who uses this Web site and its
associated documents and software?
In the last few years, this web site (http://terpconnect.umd.edu/~toh/spectrum/)
has been accessed from Internet Service Providers in over 162
countries and 6 non-region-specific categories (e.g.
satellite providers), including many countries in the developing
world, some very small countries (e.g. Liechtenstein, the Faroe
Islands), relatively isolated countries (Cuba, North Korea,
Myanmar/Burma), and even some war-torn regions (Afghanistan,
Syria, Iraq). (Internet access is often an issue. For example,
I've got fewer hits from Cuba that from other Spanish-speaking
countries with smaller populations, such as Bolivia,
Dominican Republic, Costa Rica, Puerto Rico, Panama, and Uruguay,
even though Cuba has many active scientists, especially in the
medical and pharmaceutical fields).
The first Web version went up in 1996, but I didn't start
keeping track of hits
until 2008; since then there have been over 1.9
million page views.
The distribution of page view (hit) counts among
countries is very long-tailed, with one-third of the hits coming
from the USA (except during
major US holidays), half of the hits coming from only 5
countries (USA, India, Germany, United Kingdom, and China) and 99%
of the hits coming from only 39 countries. Among the countries
that have a relatively large number of page views relative to
their populations are the USA, Germany, UK, Canada,
Australia, Netherlands, Switzerland, Singapore, Israel, Belgium,
Taiwan, South Korea, and Scandinavia. Another web site of mine on
a related subject, Interactive
Computer Models for Analytical Chemistry Instruction, had
got an additional 800,000 hits.
The Internet Service Providers with the largest number of hits are
Comcast, Verizon FIOS, Time Warner, Cloudflare, At&t U-verse,
Deutsche Telekom (Germany), BSNL (India), and Cox Communication.
Most hits worldwide come from Windows machines, about 20% from
Linux and Macintosh, and 10% from mobile devices. I've made
efforts to make my pages more usable from mobile devices like
smartphones.
About one quarter of the hits come directly from
educational institution ISPs that have "School", "Ecole",
"College", "Hochschule", "Univ...", "Academic", or "Institute of
Technology" in their names. (The number of educational users is
certainly larger than that because some users are no doubt
accessing from other ISPs in homes or businesses). An analysis of
200,000 hits in 2015 showed that the biggest educational users
have been the University of California System (UCLA,
Berkley, etc.), Indian Institute Of Technology system, the
University of Texas system, Massachusetts Institute Of Technology,
the University of Michigan, the University of Maryland (my home
institution), Delft University of Technology (Netherlands),
Stanford University, China Education And Research Network Center,
the University Of Wisconsin System, and the University of
Illinois.
Many of the large national laboratories are users, including Bell
Canada, Oak Ridge, Pacific Northwest,
Lawrence Livermore, Sandia, Brookhaven, National Renewable Energy
Laboratory, SLAC, FermiLab, Lawrence Berkeley, NRC Canada, CERN,
NIST, NASA, JPL, and NIH.
The most popular pages on the site recently have been Peak Finding and
Measurement, Smoothing,
Integration, Deconvolution, InteractivePeakFitter, and
Signal
Processing Tools. About 50% of the page views
originate from search engines (80% of those using Google). The
most common search keywords used are: "peak area", "convolution",
"deconvolution", "peak detection", "signal processing pdf",
"findpeaks matlab", "Fourier filter", and "smoothing". About
40% of the traffic comes from direct links (bookmarks or typed
URLs) and about 10% comes from referring websites, usually from Wikipedia
or from MathWorks.
Unfortunately, page loads and search terms have become
almost completely encrypted in recent years, so I can no longer
tell which pages are being viewed and what is being download.
(Interestingly, that is not the case with Interactive
Computer Models for Analytical Chemistry Instruction, which
has only 75% encryption).
There have been over 100,000 downloads of my software
and documentation files, currently averaging about 500 file
downloads per month, from both this site
and from my files on the Matlab
File Exchange. The most commonly downloaded files are
IntroToSignalProcessing.pdf,
PeakFinder.zip, ipf12.zip,
CurveFitter....xlsx, iSignal6.zip, ipeak7.zip,
PeakDetection.xlsx, and the
complete site archive SPECTRUM.zip. What factors influence the number of hits from different
countries? The tools of data analysis can help answer
this question. Obviously one would expect that a country's
population would be a factor, but it turns out that the
correlation between log(page loads) and log(population) is very
poor, with a coefficient of determination (correlation
coefficient or R2 value) of only 0.36
(n=163 countries; over 160,000 total page loads).
I also investigated the effect of other factors, including the
number of English speakers, the number of Internet users, the
number of universities, and the total research and development
budget of each country. By a good margin, the most influential
factor was the research and development
budget, for which the R2
value was 0.76. This is perhaps not surprising given that my site
concerns a very narrow and specialized topic: the technical
aspects of computerized scientific data processing.
A log-log multilinear regression on all 5 of these factors
yielded a R2 value of 0.84 (n=53
countries for which all 5 factors were reported), which is a
modest improvement over the research and development
budget alone (Graphic).
For an Excel spreadsheet with all these data and calculations (as
of May, 2015), see FinalCountriesSummary.xlsx
What fields of study are represented? The
users of my site include students, instructors, workers, and
researchers in industry, environmental, medical, engineering,
earth science, space, military, financial, agriculture,
communications, and even music and linguistics. This conclusion is
based on emails I have received, on the titles of journal articles that have cited
my work, and on the ISPs of major web visitors. A
list of specific application areas on which readers are working is
given in applications.pdf.
This page is part of "A Pragmatic
Introduction to Signal Processing", created and
maintained by Prof. Tom
O'Haver , Division of Analytical Chemistry, Department of
Chemistry and Biochemistry, The University of Maryland at College
Park. Comments, suggestions and questions should be directed to
Prof. O'Haver at toh@umd.edu.
Updated August, 2016
Unique visits to this site since
June 17, 2008:
