Full Diffusion Research Articles

Diffusion and Security Evaluation of Feistel‐PG

Feistel-PG structure is a new specific Generalized Feistel structure (GFS) adopted in DBlock and LHash. Its main feature is adding a sbox-size permutation before the round function. Different choices of the permutation may affect the security property of ciphers with Feistel-PG structure but how it effects is not clear. We evaluate the values of diffusion round for all possible parameters and summarize the characteristics of optimum shuffles. The results show that one special kind of Feistel-PG achieves full diffusion in less cost than the improved GFS. This advantage may attract the designers' interests and this kind of Feistel-PG ciphers are suggested to designers. We also evaluate the security of suggested ciphers against various byte-oriented attacks, including differential cryptanalysis, linear cryptanalysis, impossible differential attack and integral attack. Some permutations with optimum diffusion but relatively weaker security are filtered out and these permutations should be avoided by designers.

Analysis of diffusion in high entropy alloys

High-entropy alloys (HEAs) are a class of multicomponent alloys consisting of five or more principal elements with equal (or nearly equal) compositions. Diffusion plays an important role in these alloys and, indeed, if diffusion is rather sluggish, it may be partly responsible for the apparent stability of HEAs. For the understanding of diffusion properties of HEAs, the full diffusion kinetics behaviour of self-diffusion and interdiffusion in HEAs needs to be investigated. This problem is addressed in this paper by extending and applying three diffusion kinetics formalisms, one due to Darken, a combination of one from Manning and one from Holdsworth and Elliott (HE), and a ‘light’ version of one due to Moleko, Allnatt and Allnatt. Recently, an elegant and novel quasi-binary variation of a standard experimental interdiffusion set-up was used in a study of diffusion in a CoCrFeMn0.5Ni alloy [1, 2]. We successfully address these quasi-binary interdiffusion experiments analytically by applying the above random alloy diffusion kinetics formalisms for the case of CoCrFeMn0.5Ni in order to extract self-diffusion coefficients. This success now suggests that the quasi-binary variation of a standard interdiffusion set-up should be used more widely for diffusion studies in multicomponent alloys, especially HEAs.

Interactions between energetic electrons and realistic whistler mode waves in the Jovian magnetosphere

AbstractThe role of plasma waves in shaping the intense Jovian radiation belts is not well understood. In this study we use a realistic wave model based on an extensive survey from the Plasma Wave Investigation on the Galileo spacecraft to calculate the effect of pitch angle and energy diffusion on Jovian energetic electrons due to upper and lower band chorus. Two Earth‐based models, the Full Diffusion Code and the Versatile Electron Radiation Belt code, are adapted to the case of the Jovian magnetosphere and used to resolve the interaction between chorus and electrons at L = 10. We also present a study of the sensitivity to the latitudinal wave coverage and initial electron distribution. Our analysis shows that the contribution to the electron dynamics from upper band chorus is almost negligible compared to that from lower band chorus. For 100 keV electrons, we observe that diffusion leads to redistribution of particles toward lower pitch angles with some particle loss, which could indicate that radial diffusion or interchange instabilities are important. For energies above >500 keV, an initial electron distribution based on observations is only weakly affected by chorus waves. Ideally, we would require the initial electron phase space density before transport takes place to assess the importance of wave acceleration, but this is not available. It is clear from this study that the shape of the electron phase space density and the latitudinal extent of the waves are important for both electron acceleration and loss.

Fluctuations in the cross-correlation for fields lacking full diffusivity: The statistics of spurious features

Inasmuch as ambient noise fields are often not fully diffuse the question arises as to how, or whether, noise cross-correlations converge to Green’s function in practice. Well-known theoretical estimates suggest that the quality of convergence scales with the square root of the product of integration time and bandwidth. However, correlations from natural environments often show random features too large to be consistent with fluctuations from insufficient integration time. Here, it is argued that empirical seismic correlations suffer in practice from spurious arrivals due to scatterers, and not from insufficient integration time. Estimates are sought for differences by considering a related problem consisting of waves from a finite density of point sources. The resulting cross-correlations are analyzed for their mean and variance. The mean is, as expected, Green’s function with amplitude dependent on noise strength. The variance is found to have support for all times up to its maximum at the main arrival. The signal-to-noise ratio there scales with the square root of source density. Numerical simulations support the theoretical estimates. The result permits estimates of spurious arrivals’ impact on identification of cross-correlations with Green’s function and indicates that spurious arrivals may affect estimates of amplitudes, complicating efforts to infer attenuation.

In vivo visualization of connections among revised Papez circuit hubs using full q-space diffusion spectrum imaging tractography

Structural connections among the hubs of the revised Papez circuit remain to be elucidated in the human brain. As the original Papez circuit failed to explain functional imaging findings, a more detailed investigation is needed to delineate connections among the circuit’s key hubs. Here we acquired diffusion spectrum imaging (DSI) from eight normal subjects and used data from the Human Connectome Project (HCP) to elucidate connections among hubs in the retrosplenial gyrus, hippocampus, mammillary bodies, and anterior thalamic nuclei. Our results show that the ventral hippocampal commissure (VHC) was visualized in all eight individual DSI datasets, as well as in the DSI and HCP group datasets, but a strictly defined VHC was only visualized in one individual dataset. Thalamic fibers were observed to connect with both the posterior cingulate cortex (PCC) and retrosplenial cortex (RSC). The RSC was mainly responsible for direct hippocampal connections, while the PCC was not. This indicates that the RSC and PCC represent separate functional hubs in humans, as also shown by previous primate axonal tracing studies and functional magnetic resonance imaging observations.

Understanding the failure to understand New Product Development failures: Mitigating the uncertainty associated with innovating new products by combining scenario planning and forecasting

In this paper we show that New Product Development (NPD) is subject to fundamental uncertainty that is both epistemic and ontic in nature. We argue that this uncertainty cannot be mitigated using forecasting techniques exclusively, because these are most useful in circumstances characteristic of probabilistic risk, as distinct from non-probabilistic uncertainty. We show that the mitigation of uncertainty in relation to NPD requires techniques able to take account of the socio-economic factors that can combine to cause present assumptions about future demand conditions to be incorrect. This can be achieved through an Intuitive Logics (IL) scenario planning process designed specifically to mitigate uncertainty associated with NPD by incorporating insights from both quantitative modelling alongside consideration of political, social, technological and legal factors, as-well-as stakeholder motivations that are central to successful NPD. In this paper we therefore achieve three objectives: 1) identify the aspects of the current IL process salient to mitigating the uncertainty of NPD; 2) show how advances in diffusion modelling can be used to identify the social-network and contagion effects that lead to a product's full diffusion; and 3) show how the IL process can be further enhanced to facilitate detailed consideration of the factors enabling and inhibiting initial market-acceptance, and then the forecasted full diffusion of a considered new product. We provide a step-by-step guide to the implementation of this adapted IL scenario planning process designed specifically to mitigate uncertainty in relation to NPD.

Numerical Simulation of Jet Injection and Species Mixing under High-Pressure Conditions

Direct Numerical Simulation (DNS) and Large Eddy Simulation (LES) are performed of a round fluid jet entering a high-pressure chamber. The chemical compositions and temperatures of the jet and that of the fluid in the chamber are initially prescribed. The governing equations consist of the conservation equations for mass, momentum, species and energy, and are complemented by a real-gas equation of state. The fluxes of species and heat are written in the framework of fluctuation-dissipation theory and include Soret and Dufour effects. For more than two species, the full mass diffusion and thermal diffusion matrices are computed using high-pressure mixing rules which utilize as building blocks the corresponding binary diffusion coefficients. The mixture viscosity and thermal conductivity are computed using standard mixing rules and corresponding states theory. To evaluate the physical model and numerical method, LES is employed first to simulate a supercritical N2 jet injected into N2. Time averaged results show reasonable agreement with the experimental data. Then, DNS is conducted to study the spatial evolution of a supercritical N2 jet injected into CO2. Time averaged results are used to compute the length of the potential core and the species diffusion characteristics. Spectral analysis is then applied on a time series data obtained at several axial locations and a dominant frequency is observed inside the potential core.

Enhanced Dissipation, Hypoellipticity, and Anomalous Small Noise Inviscid Limits in Shear Flows

We analyze the decay and instant regularization properties of the evolution semigroups generated by two-dimensional drift-diffusion equations in which the scalar is advected by a shear flow and dissipated by full or partial diffusion. We consider both the space-periodic $${\mathbb{T}^2}$$ setting and the case of a bounded channel $${\mathbb{T} \times [0,1]}$$ with no-flux boundary conditions. In the infinite Peclet number limit (diffusivity $${\nu\to 0}$$ ), our work quantifies the enhanced dissipation effect due to the shear. We also obtain hypoelliptic regularization, showing that solutions are instantly Gevrey regular even with only partial diffusion. The proofs rely on localized spectral gap inequalities and ideas from hypocoercivity with an augmented energy functional with weights replaced by pseudo-differential operators (of a rather simple form). As an application, we study small noise inviscid limits of invariant measures of stochastic perturbations of passive scalars, and show that the classical Freidlin scaling between noise and diffusion can be modified. In particular, although statistically stationary solutions blow up in $${H^1}$$ in the limit $${\nu \to 0}$$ , we show that viscous invariant measures still converge to a unique inviscid measure.

SCIENCE, TECHNOLOGY, AND INNOVATION FOR DEFENSE IN BRAZIL: AN ANALYSIS OF TRANSFER OF TECHNOLOGY AND CHALLENGES ON BRAZILIAN DEFENSE PROGRAMS

This paper analyzes patterns in obtaining, absorbing and developing technology from major strategic defense projects. These actions aim at increasing Brazilian industrial and technological capabilities to conceive and develop defense products autonomously. The approach utilized involves analyses of different Effectiveness Criteria for Transfer of Technology policies and programs outputs, their intended outcomes, as well as intermediary results achieved so far on two defense programs, the FX-2 Gripen NG BR and the PROSUB. The research processes data from documents, news, interviews and reports to evaluate the results and what are the upcoming prospects and challenges in the defense projects. Major challenges involve the question of transfer of technology to Brazilian” national” enterprises and the effectiveness in transferring know-why in both programs. These has implications for independent production in the defense sector impairing full development and diffusion to productive chains and marketing defense products autonomously. Brazilian international insertion through strategic partnerships still needs better institutions to overcome technological blockage and a more firmly established systems of Science-Technology-Innovation in the defense sector.

Comparison of Anion Reorientational Dynamics in MCB9H10 and M2B10H10 (M = Li, Na) via Nuclear Magnetic Resonance and Quasielastic Neutron Scattering Studies

The disordered phases of the 1-carba-closo-decaborates LiCB9H10 and NaCB9H10 exhibit the best solid-state ionic conductivities to date among all known polycrystalline competitors, likely facilitated in part by the highly orientationally mobile CB9H10– anions. We have undertaken both NMR and quasielastic neutron scattering (QENS) measurements to help characterize the monovalent anion reorientational mobilities and mechanisms associated with these two compounds and to compare their anion reorientational behaviors with those for the divalent B10H102– anions in the related Li2B10H10 and Na2B10H10 compounds. NMR data show that the transition from the low-T ordered to the high-T disordered phase for both LiCB9H10 and NaCB9H10 is accompanied by a nearly two-orders-of-magnitude increase in the reorientational jump rate of CB9H10– anions. QENS measurements of the various disordered compounds indicate anion jump correlation frequencies on the order of 1010–1011 s–1 and confirm that NaCB9H10 displays jump frequencies about 60% to 120% higher than those for LiCB9H10 and Na2B10H10 at comparable temperatures. The Q-dependent quasielastic scattering suggests similar small-angular-jump reorientational mechanisms for the different disordered anions, changing from more uniaxial in character at lower temperatures to more multidimensional at higher temperatures, although still falling short of full three-dimensional rotational diffusion below 500 K within the nanosecond neutron window.

Quasi-Many-Body Localization in Translation-Invariant Systems.

We examine localization phenomena associated with generic, high entropy, states of a translation-invariant, one-dimensional spin ladder. At early times, we find slow growth of entanglement entropy consistent with the known phenomenology of many-body localization in disordered, interacting systems. At intermediate times, however, anomalous diffusion sets in, leading to full spin polarization decay on an exponentially activated time scale. We identify a single length scale which parametrically controls both the spin transport times and the apparent divergence of the susceptibility to spin glass ordering. Ultimately, at the latest times, the exponentially slow anomalous diffusion gives way to diffusive thermal behavior. We dub the intermediate dynamical behavior, which persists over many orders of magnitude in time, quasi-many-body localization.

An estimation of the effect of carbon pricing for CO2 mitigation in China’s cement industry

This study estimates the effect of carbon pricing for CO2 mitigation in China’s cement industry. The statistics and prediction show that cement production initially experienced accelerated growth and is now expected to plateau out over the next few years. The energy saving and carbon mitigation technologies considered in this estimation are at different adoption stages. Full technology diffusion is expected within 10–20years, and the remaining technology mitigation potential stands at about 8.8% by 2025 and 10.2% by 2030. Nevertheless, attaching a price to carbon would have a limited effect. Reductions of 9.9 and 12.9 Mt-CO2 might have been realised in 2015 under respective prices of 60 and 100Yuan/t-CO2, compared to a non-pricing scenario. The reduction attributed to carbon pricing would be around 4.9 Mt-CO2 in 2020 at both price levels, and around 70% of the mitigation may be at a marginal cost of 50Yuan/t-CO2 by 2020. The marginal cost for nearly 90% of the policy mitigation would be below 100Yuan/t-CO2 by 2030. This paper confirms the effectiveness of a command-and-control approach so far for energy saving in China’s cement industry and advises early introduction of a carbon pricing regime with consideration of policy interactions.

Improved ZZ a posteriori error estimators for diffusion problems: Conforming linear elements

In Cai and Zhang (2009), we introduced and analyzed an improved Zienkiewicz–Zhu (ZZ) estimator for the conforming linear finite element approximation to elliptic interface problems. The estimator is based on the piecewise “constant” flux recovery in the H(div;Ω) conforming finite element space. This paper extends the results of Cai and Zhang (2009) to diffusion problems with full diffusion tensor and to the flux recovery both in piecewise constant and piecewise linear H(div) space.

Fluctuations in the cross-correlation for fields lacking full diffusivity: The statistics of spurious features

Inasmuch as ambient noise fields are often not fully diffuse the question arises as to how, or whether, noise cross-correlations converge to Green's function in practice. Well-known theoretical estimates suggest that the quality of convergence scales with the square root of the product of integration time and bandwidth. However, correlations from natural environments often show random features too large to be consistent with fluctuations from insufficient integration time. Here it is argued that empirical seismic correlations suffer in practice from spurious arrivals due to scatterers, and not from insufficient integration time. Estimates are sought for differences by considering a related problem consisting of waves from a finite density of point sources. The resulting cross-correlations are analyzed for their mean and variance. The mean is, as expected, Green's function with amplitude dependent on noise strength. The variance is found to have support for all times up to its maximum at the main arrival. The signal-to-noise ratio there scales with the square root of source density. Numerical simulations support the theoretical estimates. The result permits estimates of spurious arrivals' impact on identification of cross-correlations with Green's function and indicates that spurious arrivals may affect estimates of amplitudes, complicating efforts to infer attenuation.

Energy and area efficient hierarchy multiplier architecture based on Vedic mathematics and GDI logic

Hierarchy multiplier is attractive because of its ability to carry the multiplication operation within one clock cycle. The existing hierarchical multipliers occupy more area and also results in more delay. Therefore, in this paper, a method to reduce the computation delay of hierarchy multiplier by employing CslA and Binary to Excess 1 Converter (BEC) is proposed. The use of BEC eliminates the n/4 number of adders, existing in the conventional addition scheme, where n denotes the multiplier input width. As the area of the hierarchy multiplier is determined by its base multiplier, the base multiplier is realized with the proposed Vedic multiplier, which has small area and operates with less delay than the conventional multipliers. In addition, the reduction of power consumption in the hierarchy multiplier can be ensured by implementing the designed multiplier with full swing Gate Diffusion Input (GDI) logic. The performances of the proposed and the existing multipliers are evaluated by Cadence SPICE simulator using 45nm technology model. From the simulation results, the performance parameters namely, delay and power consumption are calculated. Further, the area is measured from the corresponding layout for the same technology model. It is examined from the results that the proposed multiplier operates with 17% lesser power delay product than the recently reported hierarchy multiplier. The Monte Carlo simulation is performed to understand the robustness of the proposed hierarchy multiplier.

The EZ diffusion model provides a powerful test of simple empirical effects

Over the last four decades, sequential accumulation models for choice response times have spread through cognitive psychology like wildfire. The most popular style of accumulator model is the diffusion model (Ratcliff Psychological Review, 85, 59–108, 1978), which has been shown to account for data from a wide range of paradigms, including perceptual discrimination, letter identification, lexical decision, recognition memory, and signal detection. Since its original inception, the model has become increasingly complex in order to account for subtle, but reliable, data patterns. The additional complexity of the diffusion model renders it a tool that is only for experts. In response, Wagenmakers et al. (Psychonomic Bulletin & Review, 14, 3–22, 2007) proposed that researchers could use a more basic version of the diffusion model, the EZ diffusion. Here, we simulate experimental effects on data generated from the full diffusion model and compare the power of the full diffusion model and EZ diffusion to detect those effects. We show that the EZ diffusion model, by virtue of its relative simplicity, will be sometimes better able to detect experimental effects than the data–generating full diffusion model.

Maximum principles for a time–space fractional diffusion equation

In this paper, we focus on maximum principles of a time–space fractional diffusion equation. Maximum principles for classical solution and weak solution are all obtained by using properties of the time fractional derivative operator and the fractional Laplace operator. We deduce maximum principles for a full fractional diffusion equation, other than time-fractional and spatial-integer order diffusion equations.

Information technology and diffusion in the New Zealand public health sector

Purpose The purpose of this paper is to identify the influential agents that led to the successful acceptance and diffusion of the Concerto clinical workstation at the Northern District Health Board. Design/methodology/approach The paper draws on Rogers’ diffusion of innovation theory to interpret and analyse the factors that enabled acceptance and successful implementation of the innovative Concerto clinical workstation. Findings The authors conclude that human factors (clinicians) and non-human factors (the software package) simultaneously influenced the ready acceptance of the innovation. The reason for the positive acceptance and full diffusion of Concerto as compared to iHealth is the increased functionality it offers and its ability to provide clinicians with comprehensive patient records over a period of time, which assists in making informed decisions regarding the treatment, discharge, hospitalisation and recommendations for the future well-being of patients. Research limitations/implications The study focused on only one district health board (DHB); therefore, the outcomes may not be representative of all DHBs. Practical implications The study has practical implications for clinicians, DHB members and public health regulators. The outcomes illuminate the “agents” that positively influenced the diffusion of Concerto. The regulators and the DHBs can use this as a benchmark to determine how to lead the successful diffusion of information technology (IT) innovation in the public health sector. Social implications The impact on society is evident in the paper, as the use of an innovation, such as Concerto, saves time taken by clinicians to make more informed decisions regarding their patient care. Originality/value This study contributes to new knowledge by investigating the diffusion process of IT innovation with an intention of establishing the factors that enabled this process.

Connectivity Map of the Cell Interior

We are developing an imaging platform that has the appropriate spatial and time resolution to investigate fundamental biological process in regard to signaling events in cells. The technology is based on fluctuation spectroscopy and the concept of spatial cross-correlation of fluctuations at different locations (the pair correlation function approach) originally developed in our lab. This technology is a radical departure from conventional fluctuation spectroscopy methods commonly done at single points in a cell or in small regions, yet providing the same information about diffusion and binding but with additional crucial advantages. The main advantage of the pair-cross-correlation approach is that it provides the full diffusion tensor at every point in the cell, which is crucial for the determination of the flow of molecules in the cell interior. The pair-cross-correlation function is zero if the two points are not in molecular communication while is different from zero if a molecule can go from one point to the other. We show how to derive a connectivity map which visualizes which compartments in a cell are in communication and how long a molecule takes to go from one point to the other. Supported by NIH P41-GM103540 and NIH P50-GM076516 grants.

Performance improvement in tree multiplier using full swing GDI logic based CLA adder

Designing multiplier with high speed low power and minimal layout structure is of prime importance. In this paper, we propose a new architecture of 8 × 8 Wallace tree multiplier by incorporating 4-2 compressor and full adder during the partial products reduction process. Also, the final carry propagate addition is performed by carry look ahead adder to reduce the delay. Further, the multiplier is implemented using full swing gate diffusion input (GDI) logic. This design is simulated using Cadence virtuoso at 45 nm technology model. The simulation results reveal that the proposed multiplier achieves 23% power reduction than the conventional tree multiplier. Also, a large amount of reduction in wiring head is attained for the proposed multiplier. Further, an analysis of circuit's performance variation with respect to process variations is done by Monte Carlo simulation. The results confirmed that proposed multiplier has more immune against process variation while comparing with existing designs.