(1) Klamer, A. D. “Some Results Concerning Polyominoes”. Fibonacci Q. 1965, 3(1), 9-20. (2) Golomb, S. W. Polyominoes·, Scribner, New York, 1965. (3) Harary, F.; Read, R. C. “The Enumeration of Tree-like Polyhexes”. Proc. Edinburgh Math. Soc. 1970, 17, 1-14. (4) Lunnon, W. F. “Counting Polyominoes” in Computers in Number Theory·, Academic: London, 1971; pp 347-372. (5) Lunnon, W. F. “Counting Hexagonal and Triangular Polyominoes”. Graph Theory Comput. 1972, 87-100. (6) Brunvoll, J.; Cyvin, S. J.; Cyvin, B. N. “Enumeration and Classification of Benzenoid Hydrocarbons”. J. Comput. Chem. 1987, 8, 189-197. (7) Balaban, A. T., et al. “Enumeration of Benzenoid and Coronoid Hydrocarbons”. Z. Naturforsch., A: Phys., Phys. Chem., Kosmophys. 1987, 42A, 863-870. (8) Gutman, I. “Topological Properties of Benzenoid Systems”. Bull. Soc. Chim., Beograd 1982, 47, 453-471. (9) Gutman, I.; Polansky, O. E. Mathematical Concepts in Organic Chemistry·, Springer: Berlin, 1986. (10) To3i6, R.; Doroslovacki, R.; Gutman, I. “Topological Properties of Benzenoid Systems—The Boundary Code”. MATCH 1986, No. 19, 219-228. (11) Doroslovacki, R.; ToSic, R. “A Characterization of Hexagonal Systems”. Rev. Res. Fac. Sci.-Univ. Novi Sad, Math. Ser. 1984,14(2) 201-209. (12) Knop, J. V.; Szymanski, K.; Trinajstic, N. “Computer Enumeration of Substituted Polyhexes”. Comput. Chem. 1984, 8(2), 107-115. (13) Stojmenovic, L; Tosió, R.; Doroslovaóki, R. “Generating and Counting Hexagonal Systems”. Proc. Yugosl. Semin. Graph Theory, 6th, Dubrovnik 1985; pp 189-198. (14) Doroslovaóki, R.; Stojmenovió, I.; Tosió, R. “Generating and Counting Triangular Systems”. BIT 1987, 27, 18-24. (15) Knop, J. V.; Miller, W. R.; Szymanski, K.; Trinajstic, N. Computer Generation of Certain Classes of Molecules·, Association of Chemists and Technologists of Croatia: Zagreb, 1985.

SMILES, a chemical language and information system. 1. introduction to methodology and encoding rules

G. Clar 6n Rule versus Hückel 4n + 2 Rule 3464 H. Hydrocarbons versus Heteroatomic Systems 3465 IV. Hidden Treasures of Kekulé Valence Structures 3466 A. Conjugated Circuits 3467 B. Innate Degree of Freedom 3470 C. Clar Structures 3472 V. Graph Theoretical Approach to Chemical Structure 3473 A. Metric 3473 B. Chemical Graphs 3473 C. Isospectral Graphs 3473 D. Embedded Graphs 3475 E. Partial Ordering 3476 VI. On Enumeration of Benzenoid Hydrocarbons 3477 VII. Kekulé Valence Structures Count 3479 A. Non-branched Cata-condensed Benzenoids 3481 B. Branched Cata-condensed Benzenoids 3482 C. Benzenoid Lattices 3482 D. Peri-condensed Benzenoids 3483 E. Miscellaneous Benzenoids 3484 F. The Approach of Platt 3485 G. Computer Programs for Calculating K 3485 H. Transfer-Matrix Method 3486 I. Use of Recursion Relations 3486 J. Use of Signed Matrices 3487 VIII. Enumeration of Conjugated Circuits 3488 IX. Approximate Approaches versus Ambitious Computations 3490

/pdf/aromaticity-of-polycyclic-conjugated-hydrocarbons-3jl41mcpqo.pdf

Aromaticity of polycyclic conjugated hydrocarbons.

Two theoretical approaches have recently emerged to characterize new digital objects of study in the media landscape: infrastructure studies and platform studies. Despite their separate origins and different features, we demonstrate in this article how the cross-articulation of these two perspectives improves our understanding of current digital media. We use case studies of the Open Web, Facebook, and Google to demonstrate that infrastructure studies provides a valuable approach to the evolution of shared, widely accessible systems and services of the type often provided or regulated by governments in the public interest. On the other hand, platform studies captures how communication and expression are both enabled and constrained by new digital systems and new media. In these environments, platform-based services acquire characteristics of infrastructure, while both new and existing infrastructures are built or reorganized on the logic of platforms. We conclude by underlining the potential of this combi...

/pdf/infrastructure-studies-meet-platform-studies-in-the-age-of-cs5fmfehqa.pdf

Infrastructure studies meet platform studies in the age of Google and Facebook

Energetic Aspects of Cyclic Pi-Electron Delocalization: Evaluation of the Methods of Estimating Aromatic Stabilization Energies

Graph data have become ubiquitous and manipulating them based on similarity is essential for many applications. Graph edit distance is one of the most widely accepted measures to determine similarities between graphs and has extensive applications in the fields of pattern recognition, computer vision etc. Unfortunately, the problem of graph edit distance computation is NP-Hard in general. Accordingly, in this paper we introduce three novel methods to compute the upper and lower bounds for the edit distance between two graphs in polynomial time. Applying these methods, two algorithms AppFull and AppSub are introduced to perform different kinds of graph search on graph databases. Comprehensive experimental studies are conducted on both real and synthetic datasets to examine various aspects of the methods for bounding graph edit distance. Result shows that these methods achieve good scalability in terms of both the number of graphs and the size of graphs. The effectiveness of these algorithms also confirms the usefulness of using our bounds in filtering and searching of graphs.

/pdf/comparing-stars-on-approximating-graph-edit-distance-4f2ol74llb.pdf

Comparing stars: on approximating graph edit distance

A computer-oriented algorithm is developed for enumerating and generating all rigorously planar benzenoid hydrocarbons. An additional algorithm is also developed for identification and enumeration of carcinogenic bay regions. The results are reported for undisrupted benzenoid structures up to ten fused rings. The reported numbers of isomeric benzenoids do not agree with the results in the literature, because other authors included in their considerations some polyhexes which are not strictly planar structures (e.g., helicenes) or which represent rings of hexagons (e.g., circulenes). The reported results for enumeration of bay regions fully agree with those of Balasubramanian et al.

Computer enumeration and generation of benzenoid hydrocarbons and identification of bay regions

A simple computer-oriented method is presented for constructing the (molecular) distance matrix. The distance matrix considered is the graph-theoretical (topological) distance matrix.

An algorithm for construction of the molecular distance matrix

Computer enumeration and generation of trees and rooted trees

The molecular topological index (MTI) has been systematically tested for counterexamples (two or more nonisomorphic structures with the same MTI number). The analysis was carried out for alkane trees with up to 16 atoms. The search for counterexamples was positive : the first pair of alkane trees with identical MTI numbers was found in the octane family. The more disturbing finding was that two nonisomorphic alkane trees of different sizes may also possess the same MTI value. An attempt to redefine the MTI in terms of only the distance matrix and the valency matrix was abortive

Molecular topological index

This is a report on the present status of computer-aided enumeration and classification of benzenoids and coronoids (polyhexes). The existing data from previous works are displayed in comprehensive tables. Numerous data from papers in press are included, as well as original contributions.

/pdf/enumeration-of-benzenoid-and-coronoid-hydrocarbons-42pe3ff57e.pdf

Jan V. Knop

Papers

Computer enumeration and generation of benzenoid hydrocarbons and identification of bay regions

An algorithm for construction of the molecular distance matrix

Computer enumeration and generation of trees and rooted trees

Molecular topological index

Enumeration of Benzenoid and Coronoid Hydrocarbons