Control of attendance applied in higher education through mobile NFC technologies

This paper presents an improved attendance control system, required for continuous evaluation which has become compulsory following the Bologna Process. It provides a solution based on NFC technology and is based on a real project developed and pilot tested at the “Universidad Pontificia de Salamanca, Campus Madrid”.     

An automated system for PAA control and adjustment

The paper presents a classification of contemporary methods for measurement of PAA characteristics, potentialities of their development and hardware implementation. The emphasis is made on diagnostic of PAA technical state, on determination of amplitude-phase distribution (APD) over the aperture, and on PAA adjustment procedures. The paper considers technical characteristics of automated measurement systems (AMS) and of the relevant equipment. Examples of AMS application for PAA parameter determination are included.     

Effect of the green noise on the phase-locked-loop frequency-control system

The operation of the phase-locked-loop frequency-control system under the action of low-passfiltered broadband stationary noise (green noise) is considered. In order to analyze such systems, an averaging method that takes into account the external noise in a zeroth-order approximation has been constructed. Notions of an effective potential and correction process have been introduced and their role in the development of the dynamics of the system has been determined. A numerical experiment has been performed, which confirms the theoretical conclusions.     

Characteristics of the fracture surface of gray magnesium cast irons after dynamic fracture

Conclusions Modification of gray test iron with as much as 0.08% Mg leads to globularization of graphite and greatly changes the average rate of fracture. The fracture of the pearlitic matrix is brittle in character. The fracture of the pearlitic matrix is brittle in character. Thus, the discrete pattern of crack propagation observed is due mainly to the presence of graphite inclusions, which are areas of scattering of the elastic energy of the crack — relaxation areas. Comparison of the electron fractographs of cast and heat-treated samples (alloy with 0.08% Mg) revealed new elements of brittle fracture in the latter. Crack propagation in the ferritic cast iron is a ccompanied by intensive twinning (Fig. 3g, positive replica). It should be noted that ferritizing annealing has a negligible effect on the average rate of crack propagation (350 m/sec).The presence of ferrite in castings of alloys modified with 0.15 and 0.23% Mg has a negligible effect on the fracture, since the ferrite contains silicon and is therefore not a ductile phase. Comparison of the type of fracture leads to the conclusion that fracture can be regarded as brittle for all the cast irons tested. The change in the fine structure of the fracture surface with increasing magnesium concentrations first manifest in increasing signs of brittle fracture (up to 0.08% Mg) and then in weakening of these signs, is due to the change in the rate of crack propagation, which in turn depends on the shape and distribution of graphite, depending on the structural condition of the cast iron.Institute of Problems of Machine Construction, Academy of Sciences of the Ukrainian SSR. V. I. Lenin Kharkov Polytechnic Institute. Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 8, pp. 26–28, August, 1979.     

Nahalal: Cache Organization for Chip Multiprocessors

This paper addresses cache organization in chip multiprocessors (CMPs). We show that in CMP systems it is valuable to distinguish between shared data, which is accessed by multiple cores, and private data accessed by a single core. We introduce Nahalal, an architecture whose novel floorplan topology partitions cached data according to its usage (shared versus private data), and thus enables fast access to shared data for all processors while preserving the vicinity of private data to each processor. Nahalal exhibits significant improvements in cache access latency compared to a traditional cache design.     

Computation scheduling in multiprocessor real-time automatic control systems with constrained processor memory

For the automatic control systems with tight real time, construction of feasible schedules under the given job execution deadlines was considered, and in addition the constraints on processor memory were taken into consideration. Two methods were developed to solve this problem. The first method is based on reducing the original problem to the search of a multi-commodity flow in a special network. The second method offers a fast algorithm to determine a feasible schedule for the uniprocessor case.Translated from Avtomatika i Telemekhanika, No. 2, 2005, pp. 138–147.Original Russian Text Copyright © 2005 by Guz, Furugyan.     

3D Model and Estimation of Fiber Interaction Effects During Internal Instability in Non-Linear Composites

A 3D model and an estimation of fiber interaction effects during internal instability n non-linear composites are presented Results are based on a micrornechanies solution for a series of fibers embedded in an infinite non-linear incompressible matrix. An ideal bonding between the fibers and the matrix is assumed. Comparison with a limiting case in which the distance bet’ween the neighboring fibers tends to infinity is carried out. It shows the significance of the fiber interaction effects in the considered problem.     

The impact of accuracy of retaining spatial position of aperture in a waveguide-slot PAA with phase-frequency keying on radar beam parameters

The paper investigates variations of beam parameters of a plane waveguide-slot PAA with phase-frequency keying when scanning at large elevation angles and in the presence of errors arising at holding a prescribed optimal position of PAA aperture. Assessment of additional changes in beam parameters (the shape and position of the beam in the “azimuth-elevation” coordinates) is performed. The paper points to the need in high accuracy of stabilization of PAA aperture spatial position and expediency of taking stabilization errors into account.     

Application of Boundary Integral Equations to Elastodynamics of an Interface Crack

We considers application of boundary integral equations to the problem of an interface crack between two elastic half-spaces with different mechanical properties under dynamic loading. The derived system of equations allows evaluation of the displacements at the crack faces, and the traction and the displacements at the interface.