5965546
An Algorithm for Testing Structure Freeness of Biomolecular Sequences
We are concerned with a problem of checking the structure freeness of S + for a given set S of DNA sequences. It is still open whether or not there exists an efficient algorithm for this problem. In this paper, we will give an efficient algorithm to check the structure freeness of S + under the constraint that every sequence may form only linear secondary structures, which partially solves the open problem.
36727244
Horn Clause Computation by Self-assembly of DNA Molecules
Kobayashi proposed Horn clause computation by DNA molecules, which is more suitable for expressing complex algorithms than other models for DNA computing. This paper describes a new implementation of Horn clause computation by DNA. It employs branching DNA molecules for representing Horn clauses. As derivations are realized by self-assembly of such molecules, the implementation requires only a constant number of laboratory operations. Furthermore, it deals with firstorder Horn clauses with some restrictions. In order to realize first-order logic, we implement variable substitutions by string tiling proposed by Winfree, et al. As we show the computational power of a Horn clause program in our model, we give another proof that a polynomial number of operations using self-assembly of DNA molecules can compute any problem in NP.
39613508
A Magic Pot : Self-assembly Computation Revisited
Molecular computing is a novel computing paradigm recently emerged from groundbreaking wet lab experiments by Adleman in 1994. His experimental work marks a potential capability and feasibility of "one pot" computing with molecules for solving hard problems of practical size.This paper concerns a molecular computing paradigm based on "self-assembly" and "screening mechanism". After a brief getting back to and reviewing Adleman's original work, we propose a new molecular implementation method based on length-only encoding, which leads us to much simpler molecular implementation techniques to solve graph problems.With two examples, we demonstrate the effectiveness of the molecular implementation method for one pot computing based on self-assembly: one is Nondeterministic Finite Automaton Pot and the other Hamiltonian Path Problem Pot.
38554897
Tree Adjoining Grammars for RNA Structure Prediction
In this paper, we are concerned with identifying a subclass of tree adjoining grammars (TAGs) that is suitable for the application to modeling and predicting RNA secondary structures. The goal of this paper is twofold: For the purpose of applying to the RNA secondary structure prediction problem, we first introduce a special subclass of TAGs and develop a fast parsing algorithm for the subclass, together with some of its language theoretic characterizations. Then, based on the algorithm, we develop a prediction system and demonstrate the effectiveness of the system by presenting some experimental results obtained from biological data, where free energy evaluation selection for parse trees is incorporated into the algorithm.
40461039
Learning local languages and its application to protein /spl alpha/-chain identification
Concerns an efficient algorithm for learning in the limit a special type of regular language called a locally testable language from positive data, and its application to identifying the protein /spl alpha/-chain region in amino acid sequences. First, we present a linear-time algorithm that, given a locally testable language, learns (identifies) its deterministic finite state automaton in the limit from only positive data. This provides a practical and efficient learning method for a specific domain of symbolic analysis. We then describe several experimental results using the learning algorithm. Following a theoretical observation which strongly suggests that a certain type of amino acid sequence can be expressed by a locally testable language, we apply the learning algorithm to identifying the protein /spl alpha/-chain region in amino acid sequences for hemoglobin. Experimental scores show an overall success rate of 95% correct identification for positive data and 96% for negative data.<<ETX>>
32287187
Sticker systems with complex structures
Abstract In this paper, we propose a variant of sticker systems which uses molecules with complex structures. Since the original sticker systems (Paun et al. (1998) [2, 8]) working on double strands of DNA have been studied as a formal model for self-assembly in DNA computing, we extend the sticker systems to working on more complex (higher-order) structures of DNA molecules. The advantage of sticker systems with complex structures is that augmented with weak codings we can obtain the characterization of recursively enumerable languages by using only sticking (hybridization) operations for complex molecules, while the usual sticker systems require more complicated operations such as the simultaneous use of couples of dominoes or coherent computations besides morphisms.
8742017
Two Extensions of PX system
Abstract Two extensions of PX system will be discussed. The extensions are ctPX (catch/throw PX) and mvPX (multiple values PX). ctPX is a PX system extended with Nakano's catch/throw logic. ctPX enables to extract LISP programs with catch/throw mechanism form natural proofs. mvPX is a PX system which uses multiple values rather than lists to keep a finite sequences of data. Programs extracted by ctPX are more efficient than the ones by the original PX.