Upper bounds for the complexity of sparse and tally descriptions. The structure of logarithmic advice complexity classes. Harry Buhrman and Elvira Mayordomo. An excursion to the Kolmogorov random strings. Harry Buhrman and Pekka Orponen.
Random strings make hard instances.
Lance Fortnow and Martin Kummer. On resource-bounded instance complexity. Lance Fortnow and Sophie Laplante. Nearly optimal language compression using extractors. Kolmogorov complexity and instance complexity of recursively enumerable sets.