This Festschrift volume has been published in honor of Cristian Calude on the occasion of his 60th birthday and contains contributions from invited speakers and regular papers presented at the International Workshop on Theoretical Computer Science, WTCS 2012, held in Auckland, New Zealand, in February 2012. Cristian Calude has made a significant contribution to research in computer science theory. Along with early work by Chaitin, Kucera, Kurtz, Solovay, and Terwijn his papers published in the mid-1990s jointly with Khoussainov, Hertling, and Wang laid the foundation for the development of modern theory of algorithmic randomness. His work was essential for establishing the leading role of New Zealand in this area. The research interests of Cristian Calude are reflected in the topics covered by the 32 papers included in this book, namely: algorithmic information theory, algorithms, automata and formal languages, computing and natural sciences, computability and applications, logic and applications, philosophy of computation, physics and computation, and unconventional models of computation. They have been organized into four parts. The first part consists of papers discussing his life achievements. This is followed by papers in the three general areas of complexity, computability, and randomness; physics, philosophy (and logic), and computation; and algorithms, automata, and formal models (including unconventional computing).

This book constitutes the refereed proceedings of the 6th International Conference on Unconventional Computation, UC 2007, held in Kingston, Canada, in August 2007.

The 17 revised full papers presented together with 4 invited papers were carefully reviewed and selected for inclusion in the book. All current aspects of unconventional computation are addressed - theory as well as experiments and applications. Typical topics are: natural computing including quantum, cellular, molecular, neural and evolutionary computing; chaos and dynamical systems based computing; and various proposals for computations that go beyond the Turing model.

This book constitutes the refereed proceedings of the 5th International Conference on Unconventional Computation, UC 2006, held in York, UK, in September 2006. The 17 revised full papers presented together with four invited full papers were carefully reviewed and selected for inclusion in the book. All current aspects of unconventional computation are addressed - theory as well as experiments and applications.

The Fourth International Conference on Unconventional Computation, UC 2005, organized under the auspices of EATCS by the Centre for Discrete Mathematics and Theoretical Computer Science and the Department of C- puter Science and Arti?cial Intelligence of the University of Seville, was held in Seville, October 3-7, 2005. Seville, one of the most beautiful cities in Spain, is at its best in October. An explosion of colour and contrast: ?amenco, bull?ghting, and a lively at- sphere in the streets due to the open and friendly nature of its people. The river Guadalquivir, the Cathedral and the Golden Tower are all places full of magic where the visitor can feel the spirit of a city which is eternally romantic. The series of International Conferences Unconventional Computation (UC), https: //www.cs.auckland.ac.nz/CDMTCS/conferences/uc/isdevoted to all aspects of unconventional computation, theory as well as experiments and applications. Typical, but not exclusive, topics are: natural computing including quantum, cellular, molecular, neural and evolutionarycomputing; chaosand - namical systems based computing; and various proposals for computations that go beyond the Turing model. The ?rst venue of the Unconventional Computation Conference (formerly called Unconventional Models of Computation) was Auckland, New Zealand in 1998; subsequent sites of the conference were Brussels, Belgium in 2000 and Kobe, Japan in 2002. The titles of the proceedings volumes from past UC Conferences are as follows: 1. C.S. Calude, J. Casti, M.J. Dinneen (eds.). Unconventional Models of C- putation, Springer-Verlag, Singapore, 1998, viii + 426 pp. ISBN: 981-3083- 69

The main subjects of the Developments in Language Theory (DLT) conf- ence series are formal languages, automata, conventional and unconventional computation theory, and applications of automata and language theory. T- ical, but not exclusive, topics of interest include: grammars and acceptors for strings, graphs, and arrays; e?cient text algorithms; combinatorial and al- braic properties of languages; decision problems; relations to complexity theory andlogic;picturedescriptionandanalysis;cryptography;concurrency;andDNA and quantum computing. The members of the steering committee of DLT are: J. Berstel (Paris), M. Ito(Kyoto), W. Kuich(Vienna), G. P? aun(BucharestandSeville), A. Restivo (Palermo), G. Rozenberg (chair, Leiden), A. Salomaa (Turku) and W. Thomas (Aachen). The ?rst DLT conference was organized by G. Rozenberg and A. Salomaa in Turku in 1993. After this, the DLT conferences were held in every odd year: Magdeburg(1995), Thessaloniki(1997), Aachen(1999)andVienna(2001). Since 2001, a DLT conference has been organized in every odd year in Europe and in every even year outside Europe. The last two DLT conferences were organized in Kyoto, Japan in 2002 and Szeged, Hungary in 2003. The titles of the volumes of the past DLT conferences are the following: 1. Developments in Language Theory. At the Crossroads of Mathematics, C- puter Science and Biology (edited by G. Rozenberg and A. Salomaa) (1994) (World Scienti?c) 2. Developments in Language Theory II. At the Crossroads of Mathematics, Computer Science and Biology (edited by J. Dassow, G. Rozenberg and A. Salomaa) (1996) (World Scienti?c) 3. Proceedings of the Third International Conference on Developments in L- guageTheory(edite

This book constitutes the refereed proceedings of the Third International Conference on Unconventional Models of Computation, UMC 2002, held in Kobe, Japan in October 2002.The 18 revised full papers presented together with eight invited full papers were carefully reviewed and selected from 36 submissions. All major areas of unconventinal computing models are covered, especially quantum computing, DNA computing, membrane computing, cellular computing, and possibilities to break Turing's barrier. The authors address theoretical aspects, practical implementations, as well as philosophical reflections.

The refereed proceedings of the 4th International Conference on Discrete Mathematics and Theoretical Computer Science, DMTCS 2003, held in Dijon, France, in July 2003.

The 18 revised full papers presented together with 5 invited papers were carefully reviewed and selected from 35 submissions. A broad variety of topics in discrete mathematics and the theory of computing is addressed including information theory, coding, algorithms, complexity, automata, computational mathematics, combinatorial computations, graph computations, algorithmic geometry, relational methods, game-theoretic methods, combinatorial optimization, and finite state systems.

This book constitutes the refereed proceedings of the 14th International Conference on Unconventional Computation and Natural Computation, UCNC 2015, held in Auckland, New Zealand, in August/September 2015. The 16 revised full papers were carefully reviewed and selected from 38 submissions. The papers cover a wide range of topics including among others molecular (DNA) computing; quantum computing; optical computing; chaos computing; physarum computing; computation in hyperbolic spaces; collision-based computing; cellular automata; neural computation; evolutionary computation; swarm intelligence; nature-inspired algorithms; artificial immune systems; artificial life; membrane computing; amorphous computing; computational systems biology; genetic networks; protein-protein networks; transport networks; synthetic biology; cellular (in vivo) computing; and computations beyond the Turing model and philosophical aspects of computing.