4,234 research outputs found
A novel and precise time domain description of MOSFET low frequency noise due to random telegraph signals
Nowadays, random telegraph signals play an important role in integrated
circuit performance variability, leading for instance to failures in memory
circuits. This problem is related to the successive captures and emissions of
electrons at the many traps stochastically distributed at the silicon-oxide
(Si-SiO2) interface of MOS transistors. In this paper we propose a novel
analytical and numerical approach to statistically describe the fluctuations of
current due to random telegraph signal in time domain. Our results include two
distinct situations: when the density of interface trap density is uniform in
energy, and when it is an u-shape curve as prescribed in literature, here
described as simple quadratic function. We establish formulas for relative
error as function of the parameters related to capture and emission
probabilities. For a complete analysis experimental u-shape curves are used and
compared with the theoretical aproach
Nonequilibrium scaling explorations on a 2D Z(5)-symmetric model
We have investigated the dynamic critical behavior of the two-dimensional
Z(5)-symmetric spin model by using short-time Monte Carlo (MC) simulations. We
have obtained estimates of some critical points in its rich phase diagram and
included, among the usual critical lines the study of first-order (weak)
transition by looking into the order-disorder phase transition. Besides, we
also investigated the soft-disorder phase transition by considering empiric
methods. A study of the behavior of along the self-dual critical
line has been performed and special attention has been devoted to the critical
bifurcation point, or FZ (Fateev-Zamolodchikov) point. Firstly, by using a
refinement method and taking into account simulations out-of-equilibrium, we
were able to localize parameters of this point. In a second part of our study,
we turned our attention to the behavior of the model at the early stage of its
time evolution in order to find the dynamic critical exponent z as well as the
static critical exponents and of the FZ-point on square
lattices. The values of the static critical exponents and parameters are in
good agreement with the exact results, and the dynamic critical exponent
very close of the 4-state Potts model ().Comment: 11 pages, 7 figure
Logarithmic behavior of degradation dynamics in metal--oxide semiconductor devices
In this paper the authors describe a theoretical simple statistical modelling
of relaxation process in metal-oxide semiconductor devices that governs its
degradation. Basically, starting from an initial state where a given number of
traps are occupied, the dynamics of the relaxation process is measured
calculating the density of occupied traps and its fluctuations (second moment)
as function of time. Our theoretical results show a universal logarithmic law
for the density of occupied traps , i.e., the degradation is logarithmic and its amplitude depends on the
temperature and Fermi Level of device. Our approach reduces the work to the
averages determined by simple binomial sums that are corroborated by our Monte
Carlo simulations and by experimental results from literature, which bear in
mind enlightening elucidations about the physics of degradation of
semiconductor devices of our modern life
Thermodynamics on the spectra of random matrices
We show that the spectra of Wishart matrices built from magnetization time
series can describe the phase transitions and the critical phenomena of the
Potts model with a different number of states. We can statistically determine
the transition points, independent of their order, by studying the density of
the eigenvalues and corresponding fluctuations. In some way, we establish a
relationship between the actual thermodynamics with the spectral thermodynamics
described by the eigenvalues. The histogram of correlations between time series
interestingly supports our results. In addition, we present an analogy to the
study of the spectral properties of the Potts model, considering matrices
correlated artificially. For such matrices, the eigenvalues are distributed in
two groups that present a gap depending on such correlation.Comment: 10 pages, 11 figure
Overcoming inertia : drivers of the outsourcing process
Almost all managers have directly or indirectly been involved in the practice of outsourcing in recent years. But as they know, outsourcing is not straightforward. Outsourcing inertia, when companies are slow to adapt to changing circumstances that accommodate higher outsourcing levels, may undermine a firm’s performance. This article investigates the presence of outsourcing inertia and the factors that help managers overcome it. Using statistical evidence, we show that positive performance effects related to outsourcing can accumulate when circumstances change. This is then followed by rapid increases in outsourcing levels (i.e. outsourcing processes). We investigate what gives rise to these outsourcing processes through follow-up interviews with sourcing executives, which suggest five drivers behind outsourcing processes: managerial initiative (using outside experience); hierarchy (foreign headquarters); imitation (of competitors and of similar firms); outsider advice (from external institutions); knowledge sources (using external information). These five drivers all offer scope for managerial action. We tie them to academic literatures and suggest ways of investigating their presence and impact on the outsourcing process. Overall, we conclude that while economizing factors play a key role in explaining how much firms outsource, it is socializing factors that tend to drive outsourcing processes
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