Frequency properties of on-die power distribution network in VLSI circuits

The local voltage fluctuations in the supply and ground grids triggered by on-die logic cell switching in VLSI devices have been experimentally studied. The results show that these fluctuations have a resonant-like form i.e., the on-die power grid should be described as an RLC circuit. The studies reveal that the active element (i.e., CMOS logic cell) affects the frequency properties of power supply and ground grids during its switching (as opposed to before or after switching). It is demonstrated that the frequency properties of the both grids are inter-related via the interconnecting active elements.     

Case study of the predictive models used for stability improvementof the DC voltage reference source

The aim of this paper is to present a a typical application of predictive models for voltage correction in a high-precision solid-state DC voltage reference source (DCVRS). Several types of neural networks are trained until the invariant measures of dynamics, such as correlation dimension and leading Lyapunov exponent of the predicted signals, reach the values of the same invariant measures of the original signals. The predictive models are used as a segment in the software-controlled voltage reference element (VRE). A control loop is implemented to reduce the interference sensitivity of the reference source which contributes to enhancement of the robustness of the system and thereby the stability of the reference voltage     

Electronic characterization of heterojunctions by surface potential monitoring

An original approach for studying the formation of semiconductor heterojunctions and their electronic properties is discussed and illustrated. Monitoring the changes in the surface potential during the heterojunction formation lends itself to direct measurement of the band discontinuities, Debye length, and the width of the space-charge region at heterojunction interfaces. The contribution of an interface dipole is considered. The technique is demonstrated by a technologically significant experimental example.     

A learning algorithm for self-calibration of a voltage calibrator

An algorithm either to extend the calibration period or to reduce the measurement uncertainty of a DC voltage reference module is presented. This module is used either as a transfer, independent, or working standard, or as a reference module incorporated into a larger measuring system. The basic idea is that the deviation history of measured voltage differences of reference elements of a group reference module during the calibration period can be used as a learning period for a neural network. This neural network, when created, can numerically correct particular reference elements later in the working period. Results were obtained by simulation and evaluated on the basis of empirical data and simulated input functions. Hardware solutions to model this algorithm are discussed     

Subjective misconcepts of social status and coronary troubles (author's transl)

The study of various social parameters as risk factors for coronary diseases gives contradictory results. The inadequacy of social status and the consequent subjective misconcept could reconcile these apparent oppositions. The present research seems to confirm the fact that misconcepts induced by inadequacity of social status are more frequent and more intensive in patients with coronary troubles.