Difficulty in Measuring the Crustal Stress.

The difficulty of measuring the measurable.

When we were students of medicine at Zurich University, we were obliged to do a 1-month internship called Häfelipraktikum. For many of us, this job constituted the very first opportunity to become familiar with our future profession, namely with real patients in a hospital. Naturally, this Häfelipraktikum (literally, bedpan practicum) was all but an exciting experience, being precisely the most...

Measuring Parsing Difficulty Across Treebanks

One of the main difficulties in statistical parsing is associated with the task of choosing the correct parse tree for the input sentence, among all possible parse trees allowed by the adopted grammar model. While this difficulty is usually evaluated by means of empirical performance measures, such as labeled precision and recall, several theoretical measures have also been proposed in the lite...

Measuring the Difficulty of Distance-Based Indexing

Data structures for similarity search are commonly evaluated on data in vector spaces, but distance-based data structures are also applicable to non-vector spaces with no natural concept of dimensionality. The intrinsic dimensionality statistic of Chávez and Navarro provides a way to compare the performance of similarity indexing and search algorithms across different spaces, and predict the pe...

Relating Crustal Structure and Stress Indicators in the Azores Islands

Measuring instance difficulty for combinatorial optimization problems

Discovering the conditions under which an optimization algorithm or search heuristic will succeed or fail is critical for understanding the strengths and weaknesses of different algorithms, and for automated algorithm selection. Large scale experimental studies – studying the performance of a variety of optimization algorithms across a large collection of diverse problem instances – provide the...