wo CCIS researchers have received major professional association awards in recent months, honoring their

career-long contributions to their disciplines.
Trustee Professor Matthias Felleisen has
been selected as an Association for
Computing Machinery (ACM) Fellow and
Professor Betty Salzberg has been selected
as an Institute of Electrical and Electronics
Engineers (IEEE) Fellow.

“We’re extremely proud of the accomplish-
ments of these two distinguished faculty
members,” says CCIS Dean Larry Finkelstein.
“They are two of the brightest stars in the
growing constellation of talented researchers
attracted to Northeastern.”

He has made important contributions in the
design of software, program analyses, software
engineering, type theory, modular program
construction, and mathematical models of
programming languages and computation.

Felleisen is also well known for his impact in
computer science education, where he has
authored six widely-used textbooks. He has
also been the leader behind the decade-long
effort TeachScheme!, which has introduced
sophisticated programming concepts into the
introductory CS curriculum. TeachScheme!
has targeted not only the college level,
but also the secondary-school curriculum,

Felleisen was cited by the ACM for his
contributions to programming languages
and development environments. He was
one of only 41 researchers nationally to be
inducted as an ACM Fellow this year.

Over the last two decades, Felleisen and his
students have laid some of the core foundations
on which modern programming-language
theory and practice has been constructed.

where Felleisen’s team has organized
summer-session courses to teach high-school
teachers. The TeachScheme! curriculum is
currently in use at hundreds of high schools
and colleges across the world. Felleisen’s
introductory course in computer science at
Northeastern is one of the most highly
rated courses offered at the University.

Salzberg was elected as an IEEE Fellow for
her contributions to the database field
including access methods, online re-
organization methods, and robust applica-
tion techniques in computing. Much of this
work was in collaboration with David Lomet
of the Microsoft Corporation and with CCIS
graduate students. She was one of 268
inductees internationally.

Salzberg’s spatial indexing (called the
hB-tree or Holey Brick tree) clusters data
in several dimensions so that nearby data
is stored on the same disk page even when
there are insertions and deletions made
in the collection. Her temporal indexing
method (the Time-split B-tree) is an index
that is optimized to answer the query:
“show me the state of the data collection
at a given past time.” This work was in
collaboration with Lomet.

Salzberg’s work on online reorganization
concerns merging B-trees and consoli-
dation of B-trees while work is ongoing.
B-trees are the ubiquitous index in all
major DBMS products.

Most recently, Salzberg has been working
with Rui Wang, PhD ’06 and Lomet to
make an important part of database
applications recoverable.