This Ph.D. dissertation presents the result of research carried out between 1985 and 1992, first at Leiden University as a scientific assistant researcher, and later at CWI (Centre for Mathematics and Computer Science), Amsterdam, as a researcher on the NFI IIICAD project, funded by NWO (Dutch Organization for Scientific Research)...

Few technical lerms have gained such rapid notoriety as the appela tion "NP-complete." In the short lime since its introduction in the early 1970's, this term has come to symbolize the abyss of inherent intractability that algorithm designers increasingly face as they seek to solve larger and more complex problems. A...

Historically, computer security is related to both cryptography and access control in operating systems. Cryptography, although mostly applied in the military and diplomacy, was used to protect communication channels and storage facilities (especially the backups). In the seventies there was a breakthrough in cryptography - the...

In several practical circumstances we have to solve a problem whose instance is not a priori completely known. Situations of this kind occur in computer systems and networks management, in financial decision making, in robotics etc. Problems that have to be solved without a complete knowledge of the instance are called on-line...

The papers in this volume were presented at the 20th Annual International Symposium on Algorithms and Computation, held December 16–18, 2009, in Hawaii, USA. In response to the Call-for-Papers, 279 papers were submitted. Each paper received at least three reviews by either Program Committee members or experts selected by Program...