We prove that the set of DES permutations (encryption and decryption for each DES key) is not closed under functional composition. This implies that, in general, multiple DES-encryption is not equivalent to single DES-encryption, and that DES is not susceptible to a particular known-plaintext attack which requires, on average, 228 steps. We also show that the size of the subgroup generated by t...

As noted below, most researchers agree that young babies should sleep in the same room where their parents sleep. The point of disagreement is whether parents should be advised against sharing their beds. Some researchers think that the safest arrangement involves cosleeping without sharing the same bed—-i.e., placing a young infant in a crib or “side car” that is within arm’s reach of his parent.

Cribbage is (normally) a two-player card game where the aim is to score 121 points before your opponent. The game has four stages, one of which involves discarding two cards from the six cards you are dealt. A later stage scores the four cards in your hand together with a card cut randomly from the deck after the discards have been made. The two cards that were discarded are used to form anothe...

The most recent results and some of the open key questions on the evolution of early-type galaxies are reviewed in the general cosmological context of massive galaxy formation.

Tunnel structures are known as expensive infrastructures and determining optimum designs of these structures can play a great role in minimizing their cost. The formulation of optimum design of industrial tunnel sections as an optimization is considered in this paper and then the enhanced charged system search, as a recently developed meta-heuristic approach, has been applied to solve the probl...

Cognitive development is a process from an initial knowledge state at birth to a later mature one. The problem of developmental psychology is to describe and explain the intricacies of this process. In “The Scientist in the Crib”, Alison Gopnik, Andrew N. Meltzoff and Patricia K. Kuhl approach this problem from the perspective of one theory in developmental psychology — the theory theory. The b...

  We relax some assumptions of the traditional scheduling problem and suggest an adapted meta-heuristic algorithm to optimize efficient utilization of resources and quick response to demands simultaneously. We intend to bridge the existing gap between theory and real industrial scheduling assumptions (e.g., hot metal rolling industry, chemical and pharmaceutical industries). We adapt and evalua...

The vehicle routing problem with simultaneous pickup and delivery (VRPSPD) is a well-known combinatorial optimization problem which addresses provided service to a set of customers using a homogeneous fleet of capacitated vehicles. The objective is to minimize the distance traveled. The VRPSPD is an NP-hard combinatorial optimization problem. Therefore, practical large-scale instances of VR...