Symmetry2015, 7(1), 105-124; doi:10.3390/sym7010105 - published 27 January 2015 Show/Hide Abstract
Abstract: We present the first provably-secure three-party password-only authenticated key exchange (PAKE) protocol that can run in only two communication rounds. Our protocol is generic in the sense that it can be constructed from any two-party PAKE protocol. The protocol is proven secure in a variant of the widely-accepted model of Bellare, Pointcheval and Rogaway (2000) without any idealized assumptions on the cryptographic primitives used. We also investigate the security of the two-round, three-party PAKE protocol of Wang, Hu and Li (2010) and demonstrate that this protocol cannot achieve implicit key authentication in the presence of an active adversary.
Symmetry2015, 7(1), 89-104; doi:10.3390/sym7010089 - published 23 January 2015 Show/Hide Abstract
Abstract: The present experiment investigates whether patterns of shifts of feature locations could affect the same/different decisions of simultaneously presented pairs of geometrical figures. A shift of locations was defined as the angular distance from the location of a feature in one figure to the location of the same feature in another figure. It was hypothesized that the difficulty in discriminating mirror-reflected (or axisymmetric) pairs from disoriented identical pairs was caused by complex shifting patterns inherent in axisymmetric pairs. According to the shifts of the locations of the four structural features, five pair types were prepared. They could be ordered from completely identical to completely different in their shifts: identical 0/4 pairs, non-identical 1/4 pairs, non-identical 2/4 pairs = axisymmetric 2/4 pairs and non-identical 4/4 pairs. The latencies for non-identical pairs decreased with the increase of difference in the shifts of feature locations, indicating that serial, self-terminating comparisons of the shifts were applied to the discrimination of non-identical pairs from identical pairs. However, the longer latencies in axisymmetric 2/4 pairs than in non-identical 2/4 pairs suggested that the difficulty for axisymmetric pairs was not caused by the complex shifting patterns, and the difficulty was not satisfactorily explained by the comparisons of feature locations.
Symmetry2015, 7(1), 67-88; doi:10.3390/sym7010067 - published 16 January 2015 Show/Hide Abstract
Abstract: The data-analytic methodology of dihedral reductions for cyclic orbits of distinct-base codons is described both in terms of Fourier analysis over the dihedral groups and in (algebraically equivalent) terms of canonical projections. Numerical evaluations are presented for discrete and continuous scalar data indexed by cyclic orbits.
Symmetry2015, 7(1), 53-66; doi:10.3390/sym7010053 - published 14 January 2015 Show/Hide Abstract
Abstract: Machine learning is a very important approach to pattern classification. This paper provides a better insight into Incremental Attribute Learning (IAL) with further analysis as to why it can exhibit better performance than conventional batch training. IAL is a novel supervised machine learning strategy, which gradually trains features in one or more chunks. Previous research showed that IAL can obtain lower classification error rates than a conventional batch training approach. Yet the reason for that is still not very clear. In this study, the feasibility of IAL is verified by mathematical approaches. Moreover, experimental results derived by IAL neural networks on benchmarks also confirm the mathematical validation.
Symmetry2015, 7(1), 43-52; doi:10.3390/sym7010043 - published 14 January 2015 Show/Hide Abstract
Abstract: Pyranoindolizine is a tricyclic structure found in various biologically active compounds, such as camptothecin (CPT) and its derivatives. In the case of CPTs, the chirality at the α-position in the α-hydroxyl lactone moiety of pyranoindolizine is important for the antitumor activity. This paper deals with enantioselective oxidation of the α-position in pyranoindolizine lactone, which corresponds at C20 in CPT, with cumene hydroperoxide (CHP) in the presence of newly synthesized guanidine-bisurea bifunctional organocatalysts bearing chirality on both the inner and outer sides of the urea groups.