Combinatorics is generally concerned with counting arrangements
within a finite set. One of the basic problems is to determine the
number of possible configurations of a given kind. Even when the
rules specifying the configuration are relatively simple, the questions
of existence and enumeration often present great difficulties. Besides
counting, combinatorics is also concerned with questions involving
symmetries, regularity properties, and morphisms of these
arrangements. The theory of block designs is an important area where
these facts are very apparent.
Typical externally and internally pivoted shoe brakes are shown in Figures 1 and 2. In all but extremely rare designs, equal forces act upon both shoes to produce equal applied moments about their pivots. External shoe brake control is usually through a lever system that may be driven by electromechanical, pneumatic, or hydraulic means. Internal shoe brake control is usually by means of a double-ended cylinder or a symmetrical cam.
Ebook Data-Driven Block ciphers for fast telecommunication systems. Among different directions of applied cryptography, the cipher design based on the data-driven operations (DDOs) is, by comparison, poorly represented in the published and available literature.
As a companion book of Vaudenay's A Classical Introduction to Cryptography,
this exercise book contains a carefully revised version of most
of the material used in teaching by the authors or given as examinations
to the undergraduate students of the Cryptography and Security lecture
at EPFL from 2000 to mid-2005. It covers a majority of the subjects that
make up today's cryptology, such as symmetric or public-key cryptography,
cryptographic protocols, design, cryptanalysis, and implementation
Measurement of macro-geometric characteristic variables involves the acquisition of features of geometric elements that are defined in design by dimensions and tolerances for dimensional, form, and positional deviations (Figure 3.1-1). The term ‘dimension’ refers both to the diameter of rotationally symmetrical workpieces and to distances and angles between planes and straight lines and to cone angles. The sensors used for measurement can be classified according to the method used to acquire the measured value into mechanical, electrical, and optoelectronic sensors....
Privacy Enhanced Mail (PEM) was the ﬁrst serious eﬀort to secure Internet
mail. The Internet Resources Task Force (IRTF) Privacy and Security Research
Group (PSRG) did the initial design. The Internet Engineering Task Force (IETF)
PEM Working Group continued development for three years, resulting in a four-
part Proposed Internet Standard published in early 1993    . PEM
is a broad standard suite, it provides encryption, authentication, message integrity
and key management. PEM supports both symmetric and asymmetric (public-
key) key management schemes.