This volume contains the papers presented at the 11th International Wo- shop on Approximation Algorithms for Combinatorial Optimization Problems (APPROX 2008) and the 12th International Workshop on Randomization and Computation (RANDOM 2008), which took place concurrently at the MIT (M- sachusetts Institute of Technology) in Boston, USA, during August 25 27, 2008. APPROX focuses on algorithmic and complexity issues surrounding the development of e?cient approximate solutions to computationally di?cult problems, and was the 11th in the series after Aalborg (1998), Berkeley (1999), Saarbru...

The 14th international meeting on DNA computation took place in the Czech Republic in Prague, June 2 9, 2008. During the last 14 years the DNA C- puting meetings have been the key forum at the boundary between computer science, biochemistry and nanotechnology where the most recent results have been presented and their authors have met. Their scienti?c program includes mathematical foundations and theoretical study of DNA computing or b- computing in general and recent experimental results in DNA nanotechnology, nanoscience and nanocomputing. It continues to be one of the most exciting...