Edge Of Domain Research Articles

Quantifying the Performance of Cloud-Oriented Container Orchestrators on Emulated Tactical Networks

Kubernetes is the de facto industry standard for orchestrating containerized applications in clouds. Performance analyses of Kubernetes are often conducted in resource-rich environments on the enterprise or data center level. At the tactical edge domain, network resources are scarce and therefore at the opposite end of the spectrum when compared to resources available to enterprises or data centers. Computing resources (e.g., mobile or edge devices) are typically interconnected via wireless communications links that are characterized by limited bandwidth, low reliability, high latency, and frequent disconnections. This experience article describes lessons learned in constructing a suitable emulation environment for experimentation, and our findings and recommendations for running Kubernetes in tactical networks.

Edge of Chaos in Memristor Cellular Nonlinear Networks

Information processing in the brain takes place in a dense network of neurons connected through synapses. The collaborative work between these two components (Synapses and Neurons) allows for basic brain functions such as learning and memorization. The so-called von Neumann bottleneck, which limits the information processing capability of conventional systems, can be overcome by the efficient emulation of these computational concepts. To this end, mimicking the neuronal architectures with silicon-based circuits, on which neuromorphic engineering is based, is accompanied by the development of new devices with neuromorphic functionalities. We shall study different memristor cellular nonlinear networks models. The rigorous mathematical analysis will be presented based on local activity theory, and the edge of chaos domain will be determined in the models under consideration. Simulations of these models working on the edge of chaos will show the generation of static and dynamic patterns.

Unsteady transport and two-phase binding of a drug in an atherosclerotic artery

To quantify the biology and physical understanding of endovascular drug delivery, a mathematical model that accounts for the two-phase binding of drug molecules in a diseased patient-specific artery has been developed. Using an image segmentation technique, the edges of the computational domain have been successfully extracted from an asymmetric intravascular ultrasound longitudinal image. The flow inside the porous tissue is described by the Brinkman model, and the luminal flow is Newtonian. At the lumen–tissue interface, an irreversible uptake kinetics for the injected drug from the luminal side into the tissue is taken into account. Furthermore, the drug's two-phase binding process, namely, the nonspecific binding caused by the drug's trapping in the extracellular medium (ECM-bound) and the specific binding caused by the interaction between drug molecules and receptors (REC-bound), has been considered. The Marker and Cell method has been leveraged to solve the governing equations numerically. Spatiotemporal variations of free drug, ECM-bound drug, and REC-bound drug are examined thoroughly for varying absorption parameter. Simulated results reveal that the interstitial flow amplifies drug distribution, retention, and delivery effectiveness, but flow separation downstream of the constriction reduces transmural flux. Concomitantly, the larger the absorption parameter, the higher the tissue content and effectiveness; nevertheless, significantly, larger absorption parameter values do not necessarily suggest improved delivery effectiveness. A thorough sensitivity analysis was carried out to predict the effects of some of the parameters involved.

Amplitude-dependent edge states and discrete breathers in non-linear modulated phononic lattices

We explore the role of non-linearities on the spectral properties of modulated one-dimensional phononic lattices. In the linear regime, a spatial modulation of stiffness is known to produce topological gaps characterized by non-zero Chern numbers, which host topological states localized at the edges of finite domains. A continuation of the linear modes as a function of amplitude is performed, revealing a series of localization and de-localization transitions that are confirmed through direct time domain simulations. The results show that edge states whose eigenvalue branch remains within the gap remains localized, and therefore appear to be robust with respect to amplitude. In contrast, edge states whose corresponding branch approaches and remains tangential to the bulk bands experience delocalization transitions. Additionally, we observe a series of amplitude-induced phase transitions as the bulk modes become discrete breathers localized in one or more regions of the domain. Remarkably, these transitions are independent on the size of the lattice. These results bring to light the co-existence of topological edge states and discrete breathers for non-linear modulated lattices, whose interplay may exploited for amplitude-induced topological and localization transitions.

Combination of micro–macro and spatially hybrid fluid‐kinetic approach for hydrogenic plasma edge neutrals

AbstractA new hybrid fluid‐kinetic approach for the hydrogenic neutrals (atoms and molecules) in the plasma edge is presented. The hybrid approach combines a fully kinetic model for the atoms in the low‐collisional regions near the vessel wall, and for the molecules in the whole plasma edge domain, with a micro–macro approach for atoms originating from recycling at the divertor targets, volumetric recombination, and dissociation of molecules. With the micro–macro approach, the originally scattering‐dominated collision term due to charge‐exchange collisions in the kinetic equation is transformed to an absorption‐dominated term, while a large part of the neutral population is treated through a fluid approach. For JET L‐mode plasmas, the premature termination of Monte Carlo particle trajectories in the hybrid approach leads to a reduction of the CPU time by approximately a factor 3 for a high‐recycling case and by approximately a factor 11 for a partially detached case compared with a simulation with fully kinetic neutrals and the same amount of particles. For coupled fluid plasma – hybrid neutral simulations – the hybrid approach predicts the plasma divertor target profiles with a maximum hybrid‐kinetic discrepancy of approximately 30%.

Cell-Type-Dependent but CME-Independent Polar Localization of Silicon Transporters in Rice.

Silicon (Si) is an important nutrient required for sustainable and high production of rice and its uptake is mediated by a pair of influx (OsLsi1)-efflux (OsLsi2) transporters showing polar localization. However, the mechanisms underlying their polarity are unknown. Here, we revealed that the polarity of the Si transporters depends on cell types. The polar localization of both OsLsi1 and OsLsi2 was not altered by Si supply, but their protein abundance was reduced. Double immunostaining showed that localization of OsLsi1 and OsLsi2 was separated at the edge of the lateral polar domain by Casparian strips in the endodermis, whereas they were slightly overlapped at the transversal side of the exodermis. When OsLsi1 was ectopically expressed in the shoots, it showed polar localization at the xylem parenchyma cells of the basal node and leaf sheath, but not at the phloem companion cells. Ectopic expression of non-polar Si transporters, barley HvLsi2 and maize ZmLsi2 in rice, resulted in their polar localization at the proximal side. The polar localization of OsLsi1 and OsLsi2 was not altered by inhibition of clathrin-mediated endocytosis (CME) by dominant-negative induction of dynamin-related protein1A and knockout of mu subunit of adaptor protein 2 complex, although the knockout mutants of OsAP2M gene showed dwarf phenotype. These results indicate that CME is not required for the polar localization of Si transporters. Taken together, our results indicate that CME-independent machinery controls the polar localization of Si transporters in exodermis, endodermis of root cells and xylem parenchyma cells.

Beyond Edge Caching: Freshness and Popularity Aware IoT Data Caching via NDN at Internet-Scale

In-network caching is one of the main pillars of the Named Data Networking (NDN) paradigm, where every Internet router, in the path between data sources and consumers, can cache incoming content packets. Multiple strategies have been designed for caching Internet of Things (IoT) data streamed by resource-constrained devices in edge domains and wireless sensor networks, while the benefits of IoT data caching at Internet-scale, including both edge and core network segments, have not been fully disclosed. In this work, we propose and analyse a novel probabilistic Internet-scale caching design for IoT data, which jointly accounts for the content popularity and lifetime. In the considered scenario, IoT contents are requested by remote consumers and delivered by crossing multiple edge and core network segments of the NDN-based future Internet. The proposal is composed of two distinct reactive caching strategies, a coordinated and an autonomous one, to be implemented in the edge and core domain, respectively. Achieved results show that the proposal outperforms state-of-the-art solutions by providing, among others, the highest cache hit ratio and the shortest number of hops. Such performances testify a lower pressure on energy-constrained devices and on the network infrastructure, overall contributing to the sustainability of the IoT ecosystem.

On the Development and Provisioning of Vertical Applications in the Beyond 5G Era

The 5th Generation (5G) of mobile networks brings the concept of openness to vertical industries, by enabling new levels of programmability in the network core and edge domains. Openness is enabled through APIs and it creates the field for developing 5G-enabled vertical applications, i.e., applications that can interact with the underlay network. In this context, a programmability framework is envisaged, with major objective to support the development of 5G-enabled vertical applications, as well as, their testing, prior interacting with commercial networks. Implementation directions for the proposed framework are also provided, leading to a bunch of development and research-oriented takeaways.

Complex Oscillations of Chua Corsage Memristor with Two Symmetrical Locally Active Domains

This paper proposes a modified Chua Corsage Memristor endowed with two symmetrical locally active domains. Under the DC bias voltage in the locally active domains, the memristor with an inductor can construct a second-order circuit to generate periodic oscillation. Based on the theories of the edge of chaos and local activity, the oscillation mechanism of the symmetrical periodic oscillations of the circuit is revealed. The third-order memristor circuit is constructed by adding a passive capacitor in parallel with the memristor in the second-order circuit, where symmetrical periodic oscillations and symmetrical chaos emerge either on or near the edge of chaos domains. The oscillation mechanisms of the memristor-based circuits are analyzed via Domains distribution maps, which include the division of locally passive domains, locally active domains, and the edge of chaos domains. Finally, the symmetrical dynamic characteristics are investigated via theory and simulations, including Lyapunov exponents, bifurcation diagrams, and dynamic maps.

Morphology Regulation of MoS2 Nanosheet-Based Domain Boundaries for the Hydrogen Evolution Reaction

The edge of the 2H-MoS2 phase has good electrocatalytic behavior for hydrogen evolution reaction (HER). However, the shape of monolayer MoS2 synthesized under thermodynamic equilibrium conditions is triangular, which limits the density of catalytic sites at the edge of a crystal domain. The morphology of the edge of monolayer MoS2 grown under non-thermodynamic equilibrium conditions will show a large number of dendrite nanostructures. The abundant dendrite edge nanostructures make it have more catalytic site densities than monolayer MoS2 synthesized under thermodynamic equilibrium conditions. The relationship between MoO3 source supply and MoS2 fractal dimension was established through the simulation of fractal dimension. HER performance showed that the Tafel slope (59 mV/Dec) of dendrite monolayer MoS2 was much lower than that of the triangular sample (97 mV/Dec), which confirmed that the dendrite MoS2 monolayer was more conducive to the application of hydrogen evolution reaction.

Allowable complex metrics in minisuperspace quantum cosmology

Kontsevich and Segal (K-S) have proposed a criterion to determine which complex metrics should be allowed, based on the requirement that quantum field theories may consistently be defined on these metrics, and Witten has recently suggested that their proposal should also apply to gravity. We explore this criterion in the context of gravitational path integrals, in simple minisuperspace models, specifically considering de Sitter (dS), no-boundary and anti--de Sitter (AdS) examples. These simple examples allow us to gain some understanding of the off-shell structure of gravitational path integrals. In all cases, we find that the saddle points of the integral lie right at the edge of the allowable domain of metrics, even when the saddle points are complex or Euclidean. Moreover the Lefschetz thimbles, in particular the steepest descent contours for the lapse integral, are cut off as they intrude into the domain of nonallowable metrics. In the AdS case, the implied restriction on the integration contour is found to have a simple physical interpretation. In the dS case, the lapse integral is forced to become asymptotically Euclidean. We also point out that the K-S criterion provides a reason, in the context of the no-boundary proposal, for why scalar fields would start their evolution at local extrema of their potential.

Zn-assisted modification of the chemical structure of N-doped carbon dots and their enhanced quantum yield and photostability.

This article presents the Zn-assisted synthesis of N-doped carbon dots (N-CDs) with an enhanced quantum yield (QY) and photostability. There have been intensive studies to improve or tune the optical properties of carbon dots (CDs) to meet the demand for luminescent materials in various fields, including energy conversion, photocatalysis, bioimaging, and phototherapy. For these applications, the photostability of the CDs is also a critical factor, but the related studies are relatively less common. The Zn-assisted N-CDs (denoted as Zn:N-CDs) obtained by the addition of Zn(OAc)2 to the precursors during the synthesis of N-CDs not only exhibited an enhanced quantum yield but also improved photostability compared to those of N-CDs. A comprehensive study of the chemical composition of Zn:N-CD and N-CD using X-ray photoelectron spectroscopy indicated a correlation between their chemical structure and photostability. Zn(OAc)2, which acts as a catalytic reagent, induced the modification of chemical structures at the edges of carbogenic sp2 domains, without being doped in N-CD, and the heteroatom–carbon bonds in Zn:N-CD seemed to be more resistant to light compared to those in N-CDs. The increased QY and photostability of Zn:N-CDs make them more suitable as an optical probe and they could be used in fingerprint identification. With Zn:N-CDs, the microstructure of fingerprints was confirmed clearly for a long duration effectively.

Impact of Genome Reduction in Microsporidia.

Microsporidia represent an evolutionary outlier in the tree of life and occupy the extreme edge of the eukaryotic domain with some of their biological features. Many of these unicellular fungi-like organisms have reduced their genomic content to potentially the lowest limit. With some of the most compacted eukaryotic genomes, microsporidia are excellent model organisms to study reductive evolution and its functional consequences. While the growing number of sequenced microsporidian genomes have elucidated genome composition and organization, a recent increase in complementary post-genomic studies has started to shed light on the impacts of genome reduction in these unique pathogens. This chapter will discuss the biological framework enabling genome minimization and will use one of the most ancient and essential macromolecular complexes, the ribosome, to illustrate the effects of extreme genome reduction on a structural, molecular, and cellular level. We outline how reductive evolution in microsporidia has shaped DNA organization, the composition and function of the ribosome, and the complexity of the ribosome biogenesis process. Studying compacted mechanisms, processes, or macromolecular machines in microsporidia illuminates their unique lifestyle and provides valuable insights for comparative eukaryotic structural biology.

Коллапсирующие домены Ганна как механизм самоподдержания проводящего состояния в обратносмещенных высоковольтных GaAs-диодах

Switching of a high-voltage GaAs diode to the conducting state in the delayed impact-ionization mode is simulated and the results are compared with experimental data. It is shown that the effect of long-term (up to 100 ns) sustaining of the conducting state of the diode after switching is due to the appearance of narrow (of the order of a micrometer) ionizing Gunn domains, the so-called collapsing domains, in the electron-hole plasma. Impact ionization in collapsing domains and in the edge (cathode and anode) domains of a strong electric field (~300 kV/cm) maintains a high concentration of nonequilibrium carriers (≥1017 cm-3) during the entire duration of the applied reverse polarity voltage pulse.

Collapsing Gunn Domains as a Mechanism of Self-Supporting Conducting State in Reversely Biased High-Voltage GaAs Diodes

Switching of a high-voltage GaAs diode to the conducting state in the delayed impact-ionization mode is simulated and the results are compared with experimental data. It is shown that the effect of long-term (up to 100 ns) sustaining of the conducting state of the diode after switching is due to the appearance of narrow (of the order of a micrometer) ionizing Gunn domains, the so-called collapsing domains, in the electron-hole plasma. Impact ionization in collapsing domains and in the edge (cathode and anode) domains of a strong electric field (~ 300 kV/cm) maintains a high concentration of nonequilibrium carriers (≥ 1017 cm-3) during the entire duration of the applied reverse polarity voltage pulse. Keywords: high-voltage GaAs diodes, impact ionization, subnanosecond switches, Gunn effect, lock-on effect.

Resilience Enhancement at Edge Cloud Systems

It is becoming common practice to push interactive and location-based services from remote datacenters to resource-constrained edge domains. This trend creates new management challenges at the network edge, not least to ensure resilience. These challenges now need to be investigated and overcome. In this paper, we explore the use of open-source programmable asset orchestration at edge cloud systems to guarantee operational resilience and a satisfactory performance level despite system incidents such as faults, congestion, or cyber-attacks. We discuss the design and deployment of a new cross-level configurable solution, Resilient Edge Cloud Systems (RECS). Results from appropriate tests made on RECS highlight the positive effects of deploying novel service and resource management algorithms at both data and control planes of the programmable edge system to mitigate against disruptive events such as control channel issues, service overload, or link congestion. RECS offers the following benefits: i) the switch automatically selects the standalone operation mode after its disconnection from the upper-level controllers; ii) deployment of edge virtualized services is made, according to client requests; iii) the client requests are served by edge services and the related traffic is balanced among the alternative on-demand routing paths to the edge location where each service is available for its clients; iv) the TCP traffic quality is protected from unfair competitiveness of UDP flows; and v) a set of redundant controllers is orchestrated by a top-level multi-thread cluster manager, using a novel management protocol with low overhead.

Full-Field Strain Determination for Additively Manufactured Parts Using Radial Basis Functions

Additively manufactured components, especially those produced in deposition welding processes, have a rough curvilinear surface. Strain and surface deformation analysis of such components is increasingly performed using digital image correlation (DIC) methods, which raises questions regarding interpretability of the results. Furthermore, in triangulation or local tangential plane based DIC strain analysis, the principal strain directions are difficult to be calculated at any point, which is due to the non-continuity of the approach. Thus, both questions will be addressed in this article. Apart from classical local strain analysis based on triangulation or local linearization concepts, the application of globally formulated radial basis functions (RBF) is investigated for the first time, with the advantage that it is possible to evaluate all interesting quantities at arbitrary points. This is performed for both interpolation and regression. Both approaches are studied at three-dimensional, curvilinear verification examples and real additively manufactured cylindrical specimens. It is found out that, if real applications are investigated, the RBF-approach based on interpolation and regression has to be considered carefully due to so-called boundary effects. This can be circumvented by only considering the region that has a certain distance to the edges of the evaluation domain. Independent of the evaluation scheme, the error of the maximum principal strains increases with increasing surface roughness, which has to be kept in mind for such applications when interpreting or evaluating the results of manufactured parts. However, the entire scheme offers interesting properties for the treatment of DIC-data.

Estimation of Nonhomogeneous Noise in 2D Magnetic Resonance Imaging

AbstractMagnetic resonance images are often influenced by noise. Reliable estimation of noise characteristics is important for image post‐processing. The benchmark algorithms often assume a uniform noise model across the image; that is, the noise features are spatially invariant. A few noise estimators are found to cope with nonhomogeneous noise; however, they either require multiple acquisitions or other additional information. In this research work, we develop a method that can accurately estimate the nonhomogeneous parameters of noise from just a single magnitude image. The proposed algorithm is a two‐step approach. In the first step, we evaluate the standard deviation of noise assuming that it follows Gaussian distribution. This step utilizes a hybrid of spatial domain edge information suppression and transforms domain coefficient statistics to estimate a single value of standard deviation of noise in magnitude MR images. In the second step, the evaluated noise is corrected using the analytical expression that establishes the relationship between Gaussian noise and Rician noise. Results on synthetic and clinical data evidence the better performance of the proposed algorithm when compared to the benchmark methods.

Trusted Object Framework (TOF): A clustering reputation-based approach using edge computing for sharing resources among IoT smart objects

In the Cloud of Things, data are stored and processed in the cloud and the results are sent to IoT Smart Objects (SOs) with, generally, a network latency overhead due to the distances between the cloud and the local IoT networks. Moreover, trusting inappropriate counterparts can expose SOs to threats and to mitigate them we propose a clustering reputation-based approach for IoT Edge-based platform processing and storing data on the “edge”, nearby the SOs. Whenever SOs interact for services, a feedback is sent to an Edge server to calculate their reputation scores. In this way, the reputation systems is moved from the cloud to the edge servers, but available on the cloud if a SO will change edge domain. To this aim, we designed a distributed Trusted Object Framework (TOF) where heterogeneous OSs host and exploit the assistance of associated software agents and verified its performance in a simulated scenario which confirmed the potential advantages of TOF.

Neuromorphic Dynamics of Chua Corsage Memristor

Neuromorphic computing can solve computationally hard problems with energy efficiencies unattainable for von Neumann architectures. A locally-active memristor, which possesses the capability to amplify infinitesimal fluctuations in energy and can be used to generate neuromorphic behaviors, is a natural candidate for constructing an electronic equivalent of biological neurons. This paper identifies some unknown neuromorphic dynamics of the Chua corsage memristor (CCM), and shows that the CCM, when biased at the edge of chaos domain, can exhibit rich dynamics of biological neurons. Using Chua’s theories of local activity and edge of chaos, we demonstrate that under the destabilizing of the input voltage and the circuit parameters (inductance or capacitance), two CCM-based circuits can produce thirteen types of neuromorphic behaviors either on, or near the edge of chaos domain via supercritical or subcritical Hopf bifurcation. In addition, we give the conditions to test the edge of chaos of the CCM and the CCM-based circuit only by using the poles and the zero of their admittance functions.