Non-Markovian Models of Communication Networks with Adaptive Random Multiple Access Protocols

An adaptive random multiple access protocol for stabilizing bistable and unstable communication networks is designed. Non-Markovian models of these networks are studied. The traffic capacity of a network with a finite and infinite number of work stations, the asymptotic stationary distribution of state probabilities, and the main probabilistic-time characteristics of a network are determined.     

Isothermal Compressibility of TlInS2–TlPrS2 Alloys

A phase transition in TlIn_{1 – x} Pr _x S₂ (0 <x 0.08) solid solutions was detected at 260–290 K by temperature-dependent isothermal compressibility measurements, in accordance with the thermal expansion data obtained earlier.     

Negative Photoconductivity in TlIn1 –xNdxSe2(0 < x≤ 0.05) Solid Solutions

TlIn_{1 – x} Nd _x Se₂(0 < x 0.05) solid solutions were found to exhibit negative photoconductivity due to changes in the charge state of recombination centers upon carrier injection from the electrical contacts. The transient behavior of negative photoconductivity in TlIn_{1 – x} Nd _x Se₂was found to be composition-independent.     

Thermal Expansion and Isothermal Compressibility of TlIn1 – xNdxSe2 (0 ≤ x≤ 0.08) Crystals

The thermal expansion coefficient () and isothermal compressibility ( _T ) of TlIn_{1 – x} Nd _x Se₂(0 x 0.08) crystals were measured between 77 and 400 K. In the range 77–160 K, both and _T increase with temperature, the increase in being much steeper. At higher temperatures, and _T change very little. The observed composition dependences of and _T are interpreted in terms of energy-band structure.     

Estimation of the information safety level of modern infocommunication networks on the basis of the logic-probability approach

The condition of accessibility of the admissible level of protectiveness of an object of the infocommunication network from attack is stated. For the full set stipulated by irreversible, invariant, cause-effect links of the information protection functions, the logic-probability models of the estimation of protectiveness of the object of infocommunication networks are obtained. On the basis of the introduced notion of gradations of the information protection functions and their characteristics with the use of the Bayes formalism, for statistic data the statements are set up for the organization of the identification of the obtained probabilistic models with the aim to refine the current value of risk.     

A stable block model predictive control with variable implementation horizon

In this paper, we present a stable model predictive control method for discrete-time nonlinear systems. The standard MPC scheme is modified to incorporate (1) a block implementation scheme where a sub-string of the optimized input sequence is applied instead of a single value; (2) an additional constraint which guarantees that a Lyapunov function will decrease over time; (3) a variable implementation window that facilitates the stability constraint enforcement. Stability of the closed-loop system with the proposed algorithm is established. Examples are given to illustrate the effectiveness of the control scheme. The impacts of several key design parameters on the overall performance are also analyzed and discussed.     

Reduction of gate-to-channel tunneling current in FinFET structures

In this work, the gate-to-channel leakage current in FinFET structures is experimentally studied in comparison with quasi-planar very wide-fin structures, and as a function of the fin width. Devices with both doped and undoped channels and different gate stacks are studied. Experimental evidence for the reduction of gate tunneling current density in narrow FinFET structures compared to their counterpart quasi-planar structures is reported for the first time. This gate current reduction is observed for both n-channel and p-channel devices and is found to be stronger for HfO₂ than for SiON. For a given gate dielectric, the above gate current improvement in FinFETs enhances with decreasing the fin width. For SiON with an equivalent oxide thickness of 1.6 nm in undoped n-channel devices, it varies from factor of 2.3–4.3, when the fin width decreases from 75 to 25 nm. The possible reasons for the observed effect are discussed.     

Charge trapping and interface states in hydrogen annealed HfO2–Si structures

Metal–oxide–semiconductor (MOS) capacitors based on HfO₂ gate stacks with Al and TiN gates are compared to study the effect of the gate electrode material to the properties of insulator–semiconductor interface. The structures under study were shown to contain interface trap densities of around 2 × 10¹¹ cm⁻² eV⁻¹ for Al gate and up to 5.5 × 10¹² cm⁻² eV⁻¹ for TiN gate. The peak in the surface state distribution was found at 0.19 eV above the valence band edge for Al electrode. The respective capture cross-section is 6 × 10⁻¹⁷ cm² at 200 K.The charge injection experiments have revealed the presence of hole traps inside the dielectric layer. The Al-gate structure contains traps with effective capture cross-section of 1 × 10⁻²⁰ cm², and there are two types of traps in the TiN-gate structure with cross-sections of 3.5 × 10⁻¹⁹ and 1 × 10⁻²⁰ cm². Trap concentration in the structure with Al electrode was considerably lower than in the structure with TiN electrode.     

Charge trapping characterization of MOCVD HfO2/p-Si interfaces at cryogenic temperatures

The paper focuses on the study of charge trapping processes in high-k MOS structures at cryogenic temperatures. It was shown, that there is extremely strong trapping in shallow electron and hole traps, localized in the high-k dielectrics. Concentration of shallow electron traps is as much as 10¹³ cm⁻², while abnormal small capture cross-sections (4.5–8 × 10⁻²⁴ cm² for different samples, accordingly) suggests localization of shallow emitting electron traps in transition layer “high-k dielectric/Si”, more, than at the interface. Shallow hole traps with concentration near 10¹² cm⁻² are separated from silicon valence band with energy barrier in the range 10–39 meV for different samples.     

Charge accumulation in the dielectric of the nanocluster NVM MOS structures under anti- and unipolar W/E window formation

This paper focuses on the detailed study of the unipolar recharging phenomenon of the nanocluster NVM cells based upon the electron emission from the nanodots and their subsequent neutralization. It is shown that electron emission from nanodots is a very fast and effective process with a time constant <5 ms, but the subsequent neutralization of the positive accumulated charge is strongly dependent on the excess of Si atoms stored in the nanodots.