Research themes

Nils Klarlund

PhD, Cornell University, 1990
To email me, please type my address (and don't divulge it in clear text, thanks!)
Nils Klarlund in front of        whiteboard.
XML survey XML research survey. (draft version). XML: Model, Schemas, Types, Logics and Queries (with Thomas Schwentick and Dan Suciu), revised version to appear in Logics of emerging applications of databases, Eds. J. Chomicki, G. Saake, and R. van der Meyden, Springer Verlag, 2003. Related invited talk at NICTA Inaugural Formal Methods Programme Workshop.
Q14--a small        keyboard with big keys and familiar layout Language modeling for typing on Q14 and other reduced keyboards. We show that the word error rate for typing on a keyboard where adjacent keys have been clustered in pairs according to the QWERTY layout may be made almost negligible thanks to large language models used in speech recognition. newThe keyboard is now available on the BlackBerry 7100.
Foot keyboard ShortStep foot keyboard design. A radically different approach to managing computer-related discomfort. Almost every keyboard shortcut is directly accessible through foot keys. The ShortStep keyboard allows you to lean back in your chair while working on repetitive tasks with little or no use of your arms. newConcept and software are hosted at SourceForge.
Mona Making decades-old theory linking automata and logic work in practice. The concept of BDD for encoding Boolean functions plays an important role in verification. Mona is a tool based on a more general theory related to decidable fragments of arithmetic. Applications of Mona include hardware verification, protocol configuration, pointer analysis, parsing, theorem proving, etc.
ReaX Towards a foundation for multimodal, multimedia content definition. Multimedia content—where audio, video, and graphics—are synchronized in sophisticated ways is already common on the Web. Multimodal interfaces extend usability by integrating speech recognition, gestures, etc. A foundation for such work must be based on a programming language that includes concurrency, timing constraints, and built-in undo support. The survey talk (html) [Powerpoint] explains my interests in user interface technology and how they lead to fundamental questions about events and synchronicity.
ShortTalk Editing talk so enticingly efficient it is a pleasure to learn. Speech recognition as a way of getting your thoughts across the human-machine interface remains an elusive technology. ShortTalk solves the problem in the domain of text composition though a constructed editing language. Slides from talk: ShortTalk and ShortStep—with mid-20th century insights into universal and perfect languages. ShortTalk paper presented at ICME '2003 (also, ICASSP '2003). newNow available at SourceForge as open speech software offered by Carnegie Mellon University.
Input devices Usage-driven design. Since overuse injury is a long-term result, most "ergonomic" design remains unproven—despite claims of positive results in trials. I have experimented with input device concepts for over 10 years. It is my hope that the couple of surviving ideas may help other people suffering from computer-induced pain.
DSD The essentials of XML Clogged by contradictory and complex specifications, XML at heart is a welcome practical manifestation of tested ideas in computer science. With the DSD work, we try to influence the XML community through proposals rooted in programming language and automata theory. DSD 2.0 by Anders Møller can be found at the DSD Web site.
Progress measures Understanding infinite computations in terms of finite ones. In my Ph.D. thesis, I argued that infinite computations that involve liveness are best understood as limits of finite ones. The finite approximations are characterized by a progress value. For various levels of topological complexity, it is possible to formulate such measures of progress. Applications include reasoning about fairness and analyses of automata on infinite objects.


For a full list of papers, see my CV (PDF).


The papers below are just a sample. Please see papers at the Mona web site for a full list.

Automata theory


Programming languages & XML

Progress measures

User interfaces


Clairgrove LLC develops intellectual property in select areas of computer science.

My workspace: speech recognition and foot keyboard

My computer workspace is an unusual one. It is designed with the goal of virtually eliminating the usual physical strain on fingers, hands, and arms. Therefore, the use of these body parts must be drastically reduced—something that no amount of tinkering with keyboard or mouse design can achieve. The other goal is that the reassigned workspace be more efficient the conventional one; otherwise, there is no incentive to start working in different ways. These goals are usually regarded as irreconcilable. Attempting to solve the problem, I have been motivated by a typing injury (for that story see CTD-RSI).

After ten years of trial and error, I believe that I have found a promising approach. The solution is not commercially available. And, I don't know to which extent my ideas apply in general for the many people who are unable to use the keyboard and mouse in the intensive way necessitated by modern jobs.

My low-impact workspace concept integrates three user interface ideas:

The physical expression of this concept can be seen in this picture:

Photo of workspace, showing rest area for hands,    buttonless mouse, and foot pedals.
Click here for larger picture.

The video demos demonstrate how composing a letter is a breeze with speech recognition and how repetitive tasks are accomplished easily by foot work.

With the techniques illustrated in the videos, it is possible to work while leaning backwards in a relaxed manner, since hand work and finger work has been reduced to just occasionally pushing the mouse around. Therefore, the workplace puts less stress on neck and back as well.

Curriculum Vitae

Brief Vita

Nils Klarlund is the founder of Clairgrove LLC. Presently a research scientist at Google, Nils Klarlund has worked at IBM TJ Watson Research Center, the University of Aarhus, AT&T Labs--Research, and Lucent Bell Labs. His interests span user interface design, reactive programming languages, algorithms for symbolic analysis, and program testing and verification. He received a M.Sc. from the University of Aarhus and a Ph.D in Computer Science from Cornell University.


A CV is available in PDF: here.

By Nils Klarlund. Copyright ©Nils Klarlund, 2003.
XSLT & PythonPowered