A tribute to my father, Karl P. Durre
By Imke Durre
My
father, Dr. Karl Paul Durre, devoted his career in
mathematics and computer science to the design of algorithms and the
development of technological innovations that simplified written communication
between braille and print readers. Here I review both his life and his
contributions to the fields of mathematics and assistive technology.
The
early years
Born on July 20, 1937, as the youngest
of three children, my father spent his early childhood years in Reichenbach/Görlitz, Germany, where his parents operated a
residential school for children with special needs. After fleeing from the
approaching front lines during the last months of World War II, his family
moved around to various places in Austria and Germany between 1945 and 1948.
They finally settled in Delmenhorst in northern
Germany, where my father
attended secondary school and developed his lifelong interests in classical
music, track and field, and mathematics. He took up the piano at age 15, nine
years after his first musical instrument, a violin, and any dreams of playing
it, had been crushed when one of his sisters plopped herself into the chair
where my father had left the instrument after trying it out for the first time.
Though not much of an athlete himself, he took to memorizing the track and
field performances of both his classmates and the professional athletes of the
time. He thus earned himself the honor of being designated "best
theoretical athlete" by his peers at their high school graduation in 1957.
After
graduation, my father studied mathematics and physics at the universities of
Marburg and Hannover, Germany, with the goal of
becoming a high school teacher. His knack
for harnessing the power of newly emerging computer technology in devising
solutions to seemingly intractable problems, however, led him on a very
different career path.
Fascination with the four-color problem
Inspired
by the work of Prof. Heinrich Heesch at the
University of Hannover, my father became fascinated with "coloring
problems," an area of mathematics concerned with the number of colors
required for distinguishing adjoining countries on a map. Under Dr. Heesch's tutelage, my father participated in the search for
a proof to the Four-Color Theorem. This theorem states that four colors suffice
to color an arbitrary map where countries with common borders must be colored
differently. Devising innovative techniques for utilizing the limited amount of
computer memory, my father designed and implemented an algorithm for performing
computations that formed the basis for the later proof of the theorem. It is
this work that was the subject of his doctoral dissertation and led to his
earning a Ph.D. in mathematics in 1969 from the University of Hannover,
Germany.
The
availability of more advanced computing resources in the United States brought
my father to Brookhaven National Laboratory on Long Island in 1968 and 1969. The
invitation to Brookhaven was extended by Dr. Yoshio Shimamoto,
who himself was working on the four-color problem and saw great potential in the Durre-Heesch algorithm. While there, my father enjoyed the
classical music and opera scenes of New York City and traveled the
country extensively By car. These experiences left him with memories and stories
that he enjoyed sharing with his family for the rest of his life and in part contributed
to his later permanent move to the United States.
After
returning to Germany from Brookhaven, he continued to pursue his interest in
graph-coloring algorithms and their application to the compression of sparsely
populated data bases. As a research scientist, he first conducted this work in
the Department of Mathematical Machines and Data Processing at the University
of Erlangen, and in 1971 transferred to the newly established Department of
Computer Science at the University of Karlsruhe. He married in 1971 and had two children with
his wife Ingeborg, Imke and
Holger.
Pioneering
software development
My
father's passion for assistive technology was inspired by my blindness and my
parents' desire to provide me access to an equal and appropriate education
without sending me to a residential school. In Germany during the late 1970s,
there was no support system of vision resource teachers, meaning that children
with disabilities had to attend a special school. After locating a school
principal who was willing to support my parents? attempt to mainstream me in
the neighborhood school system, the Department of Education of our home state
eventually granted the school special permission to try this educational
experiment, under the premise that my parents would provide the support
necessary to access educational materials for me. It was understood that they
would also take care of the issue with access to my written homework and tests
for my classroom teachers. This was possible since my father developed a
computer-aided system that would allow for direct written communication between
blind students and their sighted teachers, peers, and family members.
Having
chosen the recently released VersaBraille from Telesensory, Inc., as the appropriate electronic braille
reading and writing device, my father tried to locate software that would allow
this device to provide instantaneous braille input and output when connected to
a personal computer. Unable to find what he was looking for, he conceived new
software and interested one of his students, Thomas Friehoff,
in the implementation of his vision. The result was BrailleButler,
a screen reader and braille display-friendly editor for the Apple IIe. The first version was completed in September 1983, the
night before I entered fifth grade in a regular German secondary school. Before
long, the system was also used by several other blind children whose parents
desired a mainstream education for them. BrailleButler
was eventually distributed and further developed by Baum Elektronik
which Thomas Friehoff later joined.
Direct
written communication through 8-dot computer braille
One
particularly useful aspect of the BrailleButler was
its reliance on an uncontracted braille code that
made full use of all eight dots available in computer braille characters, thus
allowing for a one-to-one correspondence between print and braille characters. At
that time, the number of dots in braille displays was limited to 6 dots per
cell. To increase the number of unique dot combinations, my father conceived a
method for simulating the addition of dot 7 only, dot 8 only, and dots 7 and 8
together by way of different speeds of vibration of the 6-dot characters.
Six-dot characters to which only a dot 7 was added, e.g., the capital A,
vibrated the fastest, characters containing both dots 7 and 8 vibrated the
slowest, and characters to which only dot 8 was added vibrated at an
intermediate speed. Since the VersaBraille model on
the market at the time did not have this vibrational
capability, my father arranged with Baum, Telesensory's
distributor in Germany at the time, to have a VersaBraille
specially adapted for me. Soon, the expanded functionality became a standard
feature for all new VersaBraille units. Around 1990,
with the advent of braille displays with 8-dot cells, the true 8-dot characters
replaced the different modes of vibration.
Whether
dots 7 and 8 were virtual or real, their use made it possible to expand the
number of symbols that could be represented with one braille character to four
times the number available in the traditional 6-dot system. Thanks to this
expansion, blind students now had a sufficient number of symbols to write all
assignments, including those in math and foreign languages, on the computer in
a form that both they and their sighted teachers could read. Conversely, any
person without knowledge of braille was able to make texts accessible to the
blind student by entering them into a regular word processor on a conventional
QWERTY keyboard. Furthermore, the simultaneous appearance of text in print on
the monitor and in braille on the refreshable braille display facilitated
direct written communication between blind and sighted individuals in school
and in employment settings, thus greatly simplifying the integration of blind
individuals into the regular classroom and working world.
In
a 1991 conference paper, my father, in collaboration with Dean Tuttle and my
mother, presented an Americanized version of the 8-dot code in which print
symbols were matched with braille dot combinations familiar to the American
braille reader. The authors argued that this system represented ?a user
friendly universal braille code that permits the combination of literary
English texts with foreign language and/or mathematical texts.? They regarded
an 8-dot code as an appropriate answer to the revived search for a universal
English braille code, rather than the 6-dot code others proposed. Their paper
is frequently cited in discussions about a universal braille code for the
English language and has been brought to the attention of the Braille Authority
of North America (BANA), the official entity regulating the usage of braille in
the U.S. and Canada. However, even though computers are now widely used in all
areas of life, a variety of concerns have prevented many in the United States,
among them BANA, from accepting an 8-dot code as a viable option for a
universal braille code. In Europe, on the other hand, the 8-dot code became
widely used in the 1980s and its popularity continues to this day.
Other
contributions
Together
with another of his students, my father also designed GeoTac,
an Apple IIe software that allowed blind students to
complete typical geometry assignments using a computer, joystick, and Telesensory's Optacon. Connected
to the computer, the Optacon's display showed a small
excerpt of the virtual page presented on the screen. Using a joystick, the user
could explore the contents of the entire screen. Through the system's menus,
commands could be issued that were equivalent to the functionality of a
compass, protractor, and ruler. For example, one could set a marker at a
particular point on the virtual page, use the joystick to navigate to another
spot, and choose the option of drawing a circle that was centered on the marked
point and went through the current cursor position. Other menu commands allowed
for the labeling of segments, points, and coordinate axes. The teacher or
parent could observe on the monitor?s screen every step of the drawing process,
and the work could be sent to a print printer to be turned in to the teacher.
Aside from assisting me and several other students throughout their secondary
education, GeoTac's underlying concepts laid the
foundation for the Graphics Window Professional recently developed and marketed
by Handy Tech.
Recognizing
that developments such as the BrailleButler and GeoTac make it possible for persons who are blind to be
fully integrated into society on both a personal and professional level, my
father proceeded to conceive a Support Center for blind and visually impaired
computer science and industrial engineering students at the University of
Karlsruhe in Germany. With the support of federal and state funding, the center
was established as a demonstration project in 1987 ? too late to prevent my
parents from executing their decision to move to the United States, based on an
offer from Southern Methodist University (SMU) in Dallas, Texas, to my father for
a position in the computer science department. Under the leadership of his
former colleagues, the center became a fully funded, permanent program of the
University of Karlsruhe in 1993 and continues as such to this day.
Once
in the United States, my father continued his work in the assistive technology
field, initially as a professor of computer science at SMU, from where in 1988
he transferred to the computer science department at Colorado State University
in Fort Collins. While adjusting to the English language and American academic
system, he engaged in conversations with developers and manufacturers of
blindness products, among them Telesensory and Blazie Engineering, and thus influenced the development of
devices such as the Braille 'N Speak, Navigator, and BrailleMate.
In the early 1990s, he also published papers in which he presented ideas for
making graphical user interfaces accessible to computer users who are blind.
Some of the concepts he introduced were used in the design of Baum's Windows screenreader Virgo, which was distributed in the United
States under the name ScreenPower.
Retirement
During
the early 1990s, my father's career became increasingly impacted by health
issues, and in 1994, the effects of hydrocephalus forced him into early retirement.
He then moved to Phoenix, AZ, where my mother had taken a job in view of his
health problems. Taking great pride in the professional success of his children
and wife, his life then centered around supporting all of us in our careers.
For as long as his health allowed, he took over the cooking and grocery
shopping at home and was willing to be dispatched at a moment's notice to
provide moral and practical support to my brother and me in various parts of
the country. He was always ready to dispense advice, oftentimes indirectly by
serving as a sounding board, at other times by issuing the solicited or
unsolicited, firm directives of a concerned father.
All
movement including walking and getting up from a chair became increasingly
difficult for my father, which led to the additional diagnosis of Parkinson's
disease in early 2004. With a heightened sense of urgency, he pursued his
lifelong interest in traveling, in the company of my mother, and not seldom
myself. He still took a great interest in politics and followed daily events by
reading the local newspaper and several online English and German newspapers,
although his mental abilities noticeably had started to wane. He also enjoyed
following sports events, especially in track and field and professional tennis
and shared articles with his family by forwarding them by email. My father's
death came unexpectedly on March 5, 2008, while he was enjoying a steam bath in
a local fitness room, for which he had just discovered a great love, as he
experienced an elevated sense of lightness while in the steam bath.
Personally, I will remember my father as
a warm-hearted man who did everything in his power to allow my brother and me
to obtain the best and most appropriate education possible. I will particularly
cherish my memories of the daily phone calls of the past five years during
which he and I rode our respective stationary bikes and shared thoughts about
the day?s you in our lives and in the news. Professionally,
he will be remembered for his contributions to the solution of the Four Color
Problem as well as for his pioneering work to improve the communication between
blind and sighted persons.
