Abstract.A systematic search of the 2MASS point source catalog, covering 47% of the sky, was carried out aiming to reveal any hidden globular clusters in our Galaxy. Eight new star clusters were discovered by a search algorithm based on finding peaks in the apparent stellar surface density, and a visual inspection of their vicinities yielded additional two. They all are concentrated toward the Galactic plane and are hidden behind up to A V = 20 mag which accounts for their late discovery. The majority of new clusters are associated with H regions or unidentified IRAS sources suggesting that they are young, probably similar to Arches or open clusters. Only one candidate has morphology similar to a globular cluster and the verification of its nature will require deeper observations with higher angular resolution than the 2MASS data.

Abstract. Often S-boxes are the only nonlinear component in a block cipher and as such play an important role in ensuring its resistance to cryptanalysis. Cryptographic properties and constructions of S-boxes have been studied for many years. The most common techniques for constructing S-boxes are: algebraic constructions, pseudo-random generation and a variety of heuristic approaches. Among the latter are the genetic algorithms. In this paper, a genetic algorithm working in a reversed way is proposed. Using the algorithm we can rapidly and repeatedly generate a large number of strong bijective S-boxes of each dimension from (8 × 8) to (16 × 16), which have sub-optimal properties close to the ones of S-boxes based on finite field inversion, but have more complex algebraic structure and possess no linear redundancy.

No abstract

No abstract

Abstract. Three new obscured Milky Way clusters were detected as surface density peaks in the 2MASS point source catalog during our on-going search for hidden globular clusters and massive Arches-like star clusters. One more cluster was discovered serendipitously during a visual inspection of the candidates. The first deep J, H, and K s imaging of the cluster [IBP 2002] CC 01 is presented. We estimated a cluster age of ∼1-3 Myr, distance modulus of (m − M) 0 = 12.56 ± 0.08 mag (D = 3.5 kpc), and extinction of A V ∼ 7.7 mag. We also derived the initial mass function slope for the cluster: Γ = −2.23 ± 0.16 (Γ Salpeter = −2.35). The integration over the initial mass function yielded a total cluster mass M total ≤ 1800 ± 200 M . CC 01 appears to be a regular, not very massive star cluster, whose formation has probably been induced by the shock front from the nearby H region Sh 2-228.

S-boxes play an important role in ensuring the resistance of block ciphers against cryptanalysis as often they are their only nonlinear components. The cryptographic properties of S-boxes and a variety of constructions have been studied extensively over the past years. Techniques for S-box generation include algebraic constructions, pseudo-random generation and heuristic approaches. The family of artificial immune algorithms is a particular example of a heuristic approach. In this paper we propose an S-box generation technique using a special kind of artificial immune algorithm, namely the clonal selection algorithm, combined with a slightly modified hill climbing method for S-boxes. Using this special algorithm we generate large sets of highly nonlinear bijective S-boxes of low differential uniformity in a reasonable search time.

No abstract

No abstract