Neighbor Pairs Research Articles

Polarized Population Under Imitation Dynamics in Complex Networks

Evolutionary game theory is applied in a variety of settings, ranging from economics to socio-technical networks. The core concept in evolutionary game theory is evolutionary dynamics, which determines the composition of strategies in the population at steady state. Most evolutionary dynamics are modeled to descriptively showcase the utility derived from interactions between random pairs of players in well-mixed populations, or random pairs of neighbors in structured populations. In real-life social and socio-technical networks, it is more appropriate to evaluate a player’s utility as a collection of interactions with its neighbors. To understand this; in practice, people form opinions by means of observation and imitation, by not just one friend, but a collection of friends. This paper displays a variation of the pairwise imitation dynamics where players imitate the most well-off neighbor. This process is memory-less i.e., players only use the outcome of the current game to determine their strategies in subsequent games. Empirical results demonstrate that in real-life social networks, this imitation dynamic leads to a polarized population with games that have multiple pure strategy Nash equilibria such as the Stag-Hunt game and anti-coordination games like Hawk-Dove, where an "undecided" population indefinitely swings between two strategies.

Self-consistent renormalization group approach to continuous phase transitions in alloys: application to ordering in β-brass

A self-consistent (SC) renormalization group approach of the effective medium kind has been developed and applied to the solution of the Ising model (IM). A renormalization group equation in the local potential approximation (LPA) derived previously for spatially homogeneous systems has been extended to the lattice case and supplemented with a self-consistency condition on the pair correlation function. To validate the approach it has been applied to the simple cubic IM and good agreement of the spontaneous magnetization calculated with the use of the SC–LPA equation with the available exact Monte Carlo simulations data has been established. Next the approach has been applied to the bcc IM corresponding to β-brass. With the use of the effective pair interaction parameters from available ab initio calculations the critical temperature, the correlation length and the long range order parameter in the vicinity of the critical point have been calculated in excellent agreement with experimental data. Qualitative and quantitative arguments have been given in support of the suggestion that the experimentally observed decrease of the effective critical exponent of the order parameter in comparison with the universal value is enhanced by the positive value of the second neighbour pair interaction found in the ab initio calculations.

Switchable Next-Nearest-Neighbor Coupling for Controlled Two-Qubit Operations

In a superconducting quantum processor with nearest neighbor coupling, the dispersive interaction between adjacent qubits can result in an effective next-nearest-neighbor coupling whose strength depends on the state of the intermediary qubit. Here, we theoretically explore the possibility of engineering this next-nearest-neighbor coupling to implement controlled two-qubit operations where the intermediary qubit controls the operation on the next-nearest neighbor pair of qubits. In particular, in a system comprising two types of superconducting qubits with anharmonicities of opposite-sign arranged in an -A-B-A- pattern, where the unwanted static ZZ coupling between adjacent qubits could be heavily suppressed, a switchable coupling between the next-nearest-neighbor qubits can be achieved via the intermediary qubit, the qubit state of which functions as an on/off switch for this coupling. Therefore, depending on the adopted activating scheme, various controlled two-qubit operations such as controlled-iSWAP gate can be realized, potentially enabling circuit depth reductions as to a standard decomposition approach for implementing generic quantum algorithms.

Combining DFT and CALPHAD for the development of on-lattice interaction models: The case of Fe-Ni system

We present a model of pair interactions on rigid lattice to study the thermodynamic properties of iron-nickel alloys. The pair interactions are fitted at 0 K on ab initio calculations of formation enthalpies of ordered and disordered (special quasirandom) structures. They are also systematically fitted on the Gibbs free energy of the $\ensuremath{\gamma}$ Fe-Ni solid solution as described in a CALPHAD (CALculation of PHAse Diagrams) study by Cacciamani et al. This allows the effects of finite temperature, especially those of magnetic transitions, to be accurately described. We show that the ab initio and CALPHAD data for the $\ensuremath{\gamma}$ solid solution and for the $\mathrm{Fe}{\mathrm{Ni}}_{3}\text{\ensuremath{-}}\mathrm{L}{1}_{2}$ ordered phase can be well reproduced, in a large domain of composition and temperature, using first and second neighbor pair interactions which depend on temperature and local alloy composition. The procedure makes it possible to distinguish and separately compare magnetic, chemical, and configuration enthalpies and entropies. We discuss the remaining differences between the pair interaction model and CALPHAD, which are mainly due to the treatment of the short-range order and configurational entropy of the solid solution. The FCC phase diagram of the Fe-Ni system is determined by Monte Carlo simulations in the semigrand canonical ensemble and is compared with experimental studies and other models. We especially discuss the stability of the $\mathrm{Fe}\mathrm{Ni}\text{\ensuremath{-}}\mathrm{L}{1}_{0}$ phase at low temperature.

Polynomial functions for configurational correlation functions in Gibbs energies of solid solutions using cluster variation method

The cluster expansion – cluster variation methods (CE – CVM) offer a reliable framework to obtain short range order information for the chosen configurational state of a system accurate up to the basic cluster chosen in terms of the microscopic state variables called correlation functions (CFs). The calculation of the CFs involves solving a set of nonlinear equilibrium equations using compute intensive numerical methods. In this paper a method is presented to approximate the equilibrium values of CFs as polynomial functions of composition which eliminate the necessity of solving equilibrium equations. The coefficients of these polynomials are expressed as rational functions of temperature and system specific energy parameters. This method is comparable to standard CALPHAD methods in its ease of application without sacrificing information about short range order in the system.This procedure is applied to an A2–B32 system using tetrahedron approximation for the case of exclusive second neighbour pair interactions. These polynomials yield CFs comparable to those obtained from numerical solutions in the usual ranges of energy parameters and temperatures.

Regulatory Harmonization and Collaborative Governance: Exploring the Shared Micromobility Policy Practices for Post-pandemic Deployment

Local governments across the United States took vastly different approaches to the regulation of dockless e-scooter sharing, resulting in a patchwork of regulatory policies. While recent literature suggested, there is evidence of convergence amongst cities with similar characteristics, the extent of harmonized jurisdictional e-scooter policies had not yet been investigated. With the future of public and shared transportation already tenuous due to COVID-19, this paper investigates the different rules and regulations threatening the resurgence of fleet operations in neighboring jurisdictions. The research team first explored precedent and mechanisms for transportation harmonization at different levels of government, and second, studied the degree of harmonization of neighboring jurisdictions. The paper uses a comparative multi-case study approach of six neighbor pairs to uncover patterns of harmonization between neighboring jurisdictions. Findings indicate a convergence of harmonization between equal-sized cities appears more frequently than disparate cities, supporting previous research. Also, pairs in states which follow Dillon's Rule show alignment in the device, safety, insurance, and right-of-way policies, whereas home rule neighbors more frequently diverge from each other. These findings highlight the need to understand regional policy harmonization better. Submitted for presentation at the 100th Annual Meeting of the Transportation Research Board and for publication at the Transportation Research Record journal

Texture Based Segmentation of Remotely Sensed Images

Texture based segmentation approach extracts homogeneous regions that have similar texture properties. The texture patterns make use of the gray scale relationship between the center pixel and its surrounding neighbors. In this paper, a novel method is proposed that encodes the spatial relationship between adjacent pairs of neighbors on either side of the center pixel including itself along the given directions in an image. The novelty of the proposed method is that the texture operator is applied on multiple windows of the image to produce a stack of images from which the texture pattern is obtained. The proposed operator is applied on SAR images of ocean surface to detect regions of interest like ship or slick. Keywords: Binary pattern, De-speckle, Gradient, Segmentation, Watershed.

X-ray scattering study of water confined in bioactive glasses: experimental and simulated pair distribution function.

Temperature-dependent total X-ray scattering measurements for water confined in bioactive glass samples with 5.9 nm pore diameter have been performed. Based on these experimental data, simulations were carried out using the Empirical Potential Structure Refinement (EPSR) code, in order to study the structural organization of the confined water in detail. The results indicate a non-homogeneous structure for water inside the pore, with three different structural organizations of water, depending on the distance from the pore surface: (i) a first layer (4 Å) of interfacial pore water that forms a strong chemical bond with the substrate, (ii) intermediate pore water forming a second layer (4-11 Å) on top of the interfacial pore water, (iii) bulk-like pore water in the centre of the pores. Analysis of the simulated site-site partial pair distribution function shows that the water-silica (Ow-Si) pair correlations occur at ∼3.75 Å. The tetrahedral network of bulk water with oxygen-oxygen (Ow-Ow) hydrogen-bonded pair correlations at ∼2.8, ∼4.1 and ∼4.5 Å is strongly distorted for the interfacial pore water while the second neighbour pair correlations are observed at ∼4.0 and ∼4.9 Å. For the interfacial pore water, an additional Ow-Ow pair correlation appears at ∼3.3 Å, which is likely caused by distortions due to the interactions of the water molecules with the silica at the pore surface.

Local electrochemical characteristics of pure iron under a saline droplet I: Effect of droplet size on electrochemical distribution

Despite historically being the focus of much research and measurement development, atmospheric corrosion under saline droplets and its underlying mechanisms continues to require more accurate investigations. Toward this goal, the electrochemical distributions of pure iron under different volumes of 3.5% NaCl droplets at different elapsed times were investigated using newly developed concentric three-electrode array measurements. The results showed that the electrochemical distribution under a droplet was directly affected by the droplet size. Distributions of corrosion potential and galvanic current on the CTEA under a 110 μL droplet were circumferentially symmetric; whereas, the electrochemical distribution under a 25 μL droplet was characterized by a neighboring peak-valley pair, and that of a 340 μL droplet exhibited multiple adjacent peaks and valleys. The asymmetric electrochemical distributions under droplets with volumes of 25 μL and 340 μL can be attributed to the difference between the droplet sizes and the effective influencing distance of the corrosion couple, which is determined by the corrosion potential difference between the anode and cathode, the galvanic current, and the anodic and cathodic polarizabilities. The standard deviations of galvanic current trend indicated a greater tendency towards localized corrosion under the 110 μL droplet after a coupling period of 60 min. The results suggested that a droplet with the proper size and electrochemical distribution symmetry is more likely to initiate and develop local atmospheric corrosion.

A maximum entropy principle approach to a joint probability model for sequences with known neighbor and next neighbor pair probabilities

A Markov chain can be used to model a joint probability density of a sequence, pR1R2...RNx1,x2,..xN, from neighbor pair probability data: pRnRn+1xn|xn+1n=1,2,...N-1, the Rn′s specifying the type of random variable, xn. A Maximum Entropy Principle (MEP) is used to show that, with knowledge of only these neighbor pair probabilities, the Markov chain maximizes entropy. To introduce more information, it would be useful to consider triplet probabilities, but data limitations may preclude this approach. Instead, the joint probability density function is modeled with neighbor and next neighbor pair probabilities. Optimized triplet probabilities are obtained from these probabilities, again using a MEP method, and an augmented Markov chain is constructed from them. This joint probability density function is the MEP joint probability density function with known neighbor and next neighbor pair probabilities. Based on this information, we construct various length Markov and augmented Markov chains to produce diverging patterns of chain probabilities.

Entanglement entropy in the spin-1/2 Heisenberg chain with hexamer modulation of exchange

The spin-1/2 isotropic alternating Heisenberg chains with hexamer modulation of exchange are considered. Recently, the ground state phase diagram of the model was obtained for different patterns of modulations in the limit of strong antiferromagnetic exchange coupling on odd links. In addition to the zero and saturated-magnetization plateaus, two gapped plateau states were recognized in the presence of a uniform magnetic field. Here, using the numerical Lanczos method, the ground state of finite chain systems is calculated and the behavior of the entanglement entropy (EE) and the concurrence is studied. First, we divided the chain system into two subsystems A and B and focus on EE which shows how much subsystems A and B are entangled. Results show that a pair of spins located on a strong antiferromagnetic link is entangled in the gapped mid plateau states. On the other hand, a pair of spins located on a weak link is completely entangled with the rest of the chain in the zero-magnetization plateau state. Second, we focused on the entanglement between nearest neighbor pair spins and the concurrence is calculated numerically. Pair spins on non-modulated links will be entangled only in the first or the second gapped plateau phases.

Approach to control magnetic plateau in tetrameric magnetic systems

We study the magnetic behavior of a tetrameric magnetic system with four antiferromagnetic couplings(J1-J2-J3-J4), where J4 is the inter-cell coupling and J1,J2,J3 are the intra-cell couplings, by using Green’s function theory. The Magnetic-field curves shows that there are three plateaus (M = 0, 1 and saturated magnetization) and two gapless phases distinguished by four critical lines, and the plateaus widen or narrow with the inter-cell coupling(J4), which are further explained using the energy spectrum. In addition, it is found that the magnetic contribution from each site of the unit cell is different due to the competition of the nearest neighboring pair interactions, which is demonstrated by the concurrence of the biparticle quantum state.

Prime stars multiplexes

This work investigates the class of prime star multiplex networks, where each layer consists of a regular cycle graph with a prime number of nodes N. Within a layer, all nodes have the same degree, being connected to one or more pairs of nearest neighbors. In the first layer, the nodes are labeled in sequentially ascending order. Without affecting any cyclic topology, the module function is used to relabel the nodes of the other layers, in such a way that labels of subsequent nodes along the cycle differ by a constant value p > 1, with different values of p for each layer. When assembling the multiplex network, all nodes with the same label are drawn on the top of the other, according to the sequential order of the first layer, so that the introduced inter-layer connections among all representations of the same node in the different layers are represented by vertical lines. In this way, a regular prime star geometry arises in all but the first layer, revealing very dissimilar layers and long distance shortcuts in the multiplex. Several matrices representing such structures as well as physical models defined on them satisfy the circulant property. Results based on analytical and numerical approaches for two-layer multiplex networks are presented. Particular attention is devoted to the characterization of the layer dissimilarity and to the efficiency of diffusive processes, including the presence of super-diffusion. They reveal a complex pattern, which depends on the values of p and of the node degree inside each layer. It is also shown that results for diffusive processes are deeply connected with the interlayer dissimilarity.

Efficacy and Spatial Extent of Yard-Scale Control of Aedes (Stegomyia) albopictus (Diptera: Culicidae) Using Barrier Sprays and Larval Habitat Management

The Asian tiger mosquito, Aedes (Stegomyia) albopictus (Skuse), is a peridomestic, container-ovipositing mosquito commonly found throughout the southeastern United States. In the United States, Ae. albopictus is typically considered a nuisance pest; however, it is capable of transmitting multiple pathogens. Ae. albopictus is an important pest species and the target of numerous mosquito control efforts in the United States. Here, we evaluate the effectiveness and spatial extent of Ae. albopictus population reduction using a bifenthrin (AI Bifen IT, 7.9%) barrier spray and larval habitat management (LHM) in a temperate, suburban setting. Sixteen pairs of adjoining neighbors were randomly assigned to treatment groups with one neighbor receiving a treatment and the other monitored for evidence of a spillover effect of the treatments. Ae. albopictus populations in both yards were monitored for 33 d, with treatments occurring on the eighth day. Barrier sprays, both alone and combined with LHM, resulted in a significant reduction in Ae. albopictus abundance posttreatment. While LHM alone did not result in a significant reduction over the entire posttreatment period, Ae. albopictus populations were observed to be in decline during this period. No treatments were observed to have any reduction in efficacy 25 d posttreatment, with treatments involving LHM having a significantly increased efficacy. Yards neighboring treated yards were also observed to have reduced population sizes posttreatment, but these differences were rarely significant. These results provide insights into the population dynamics of Ae. albopictus following two common treatments and will be useful for integrated pest management plans.

Leader–Follower Network Aggregative Game With Stochastic Agents’ Communication and Activeness

This article presents a leader–follower scheme for network aggregative games. The followers and leader are selfish cost minimizing agents. The cost function of each follower is affected by its own strategy, the strategy of leader and the aggregate strategy of its neighbors through a communication graph. Also, the leader's cost function depends on its own strategy and the aggregate strategy of all the followers. The leader infinitely often wakes up, receives the aggregate strategy of the followers, updates its decision value, and broadcasts it to all the followers. Then, the followers apply the updated strategy of the leader into their cost functions. The establishment of information exchange between each neighboring pair of followers, and also, decision updating by a follower at each iteration, that is to say the activeness of the follower in that iteration, are both considered to be drawn from two arbitrary distributions. Moreover, a distributed algorithm based on subgradient method is proposed for updating the strategies of leader and followers. The convergence of the proposed algorithm to the unique Stackelberg equilibrium point of the game is proven in both almost sure and mean square senses.

Comparison of the nitrogen balance in paddy fields under conventional rice straw application versus cow dung compost application in mixed crop–livestock systems

ABSTRACT In Japan, rice straw (RS) is commonly incorporated into the soil after harvest to maintain the fertility of paddy soil. However, in mixed crop–livestock systems, RS is collected to feed livestock and then cow dung compost (CDC) is applied to the fields. We found in previous research that CDC supplied more N to the fields than RS, but the soil total N and available N of fields to which CDC was applied were similar to those receiving conventional RS application. To identify the reason for this result, we investigated the N inputs (organic matter, fertilizer, N fixation), N outputs (plant N uptake, N leaching loss), and the N balance of RS application (RS treatment) and RS removal plus CDC application (CDC treatment) in 10 neighboring paddy field pairs in Mamurogawa town, Yamagata Prefecture, Japan. The N fertilizer contributed the highest percentage to total N input, followed by organic matter and N fixation. The amounts of N fertilizer and N fixation in the RS treatment were similar to those in the CDC treatment. CDC contributed significantly more N to the fields than RS, but the total N input was similar between treatments. The N output from plant N uptake and leaching loss were higher in the CDC treatment than the RS treatment, but the difference was not significant. Plant N uptake was the main N output, accounting for 98% of total N output. The N balance was positive and similar between treatments. Therefore, the non-significant differences in total N input, total N output, and N balance between treatments explain the similarity in soil total N and available N.

Efficient distributed average consensus in wireless sensor networks

Computing the distributed average consensus in Wireless Sensor Networks (WSNs) is investigated in this article. This problem, which is both natural and important, plays a significant role in various application fields such as mobile agents and fleet vehicle coordination, network synchronization, distributed voting and decision, load balancing of divisible loads in distributed computing network systems, and so on. By and large, the average consensus’ objective is to have all nodes in the network converged to the average value of the initial nodes’ measurements based only on local nodes’ information states. In this paper, we introduce a fully distributed algorithm to average the sensed data within the network itself. The network may be large since we never broadcast over all its nodes. Unlike earlier works, when a node detects a load (scalar value) imbalance in its closed neighborhoods during the average process, instead of sending parsimonious amount of load values from highly loaded nodes to less loaded ones, we move a large amount of load values by involving parallel atomic transactions between mutually exclusive pairs of neighbors. This improves the global convergence time speedup with low-cost communication and minimal energy consumption. First, we give the convergence proof of the distributed consensus process, and next we provide some experimental results based on NS3 framework to assess the behavior of the proposed algorithm.

Magnetic ripple domain structure in FeGa/MgO thin films

The magnetic domain structure is studied in epitaxial Fe100-xGax/MgO(001) films with 0 < x < 30 and thicknesses below 60 nm by magnetic force microscopy. For low gallium content, domains with the magnetization lying in the film plane and domain walls separating micrometric areas are observed. Above x ≈ 20, the magnetic contrast shows a fine corrugation, ranging from 300 to 900 nm, suggesting a ripple substructure with a periodic oscillation of the magnetization. We discuss the presence of a random magnetic anisotropy contribution, that superimposed to the cubic coherent anisotropy, is able to break the uniform orientation of the magnetization. The origin of that random anisotropy is attributed to several factors: coexistence of crystal phases in the films, inhomogeneous distribution of both internal strain and Ga–Ga next nearest neighbor pairs and interface magnetic anisotropy due to the Fe–O bond.

Phonon characteristics of Si‐doped InAs grown by gas‐source molecular beam epitaxy

AbstractUsing Raman scattering spectroscopy with 514‐ and 633‐nm light sources, we have studied the phonon characteristics of Si‐doped InAs films grown on (100) n‐type InAs by gas‐source molecular beam epitaxy having charge carrier concentration (n) between 2.26 × 1018 and 1.68 × 1020 cm−3. The unscreened longitudinal optical (LO) phonon is observed near ~238 cm−1 along with two plasmon‐LO‐phonon (PLP) coupled L± modes. With increasing n, the L− mode is downshifted from the LO phonon towards the transverse optical mode frequency. This abnormal behavior is ascribed to the large scattering vector and heavy Landau damping. The L+ mode close to the plasma frequency ωP is also detected in samples with n &gt; 1019 cm−3. The observed unscreened LO mode in the forbidden configuration is attributed to the resonance enhanced scattering induced by surface space charge. Reliable values of charge carrier density and mobility are estimated from the simulated shifts of PLP modes in the low Si‐doped InAs films. At higher doping level, a full‐line shape analysis is desired for assessing accurate values of the transport parameters. In Si‐doped InAs, we appraised the existing experimental data of localized vibrational modes (LVMs) from Raman and Fourier transform infrared spectroscopy by exploiting a sophisticated Green's function theory and incorporating lattice relaxation effects around SiIn and SiAs defects for constructing accurate perturbation models. The simulated results of LVMs for several isolated (Td) defects, nearest neighbor pair (C3v), and next‐nearest neighbor complex centers (Cs) are compared, contrasted, and discussed with the experimental data.

Ground state of weakly repulsive soft-core bosons on a sphere

We study a system of penetrable bosons embedded in a spherical surface. Under the assumption of weak interaction between the particles, the ground state of the system is, to a good approximation, a pure condensate. We employ thermodynamic arguments to investigate, within a variational ansatz for the single-particle state, the crossover between distinct finite-size "phases" in the parameter space spanned by the sphere radius and the chemical potential. In particular, for radii up to a few interaction ranges we examine the stability of the fluid phase with respect to a number of crystal-like arrangements having the symmetry of a regular or semi-regular polyhedron. We find that, while quantum fluctuations keep the system fluid at low density, upon compression it eventually becomes inhomogeneous, i.e., particles gather together in clusters. As the radius increases, the nature of the high-density aggregate varies and we observe a sequence of transitions between different cluster phases ("solids"), whose underlying rationale is to maximize the coordination number of clusters, while ensuring at the same time the proper distance between each neighboring pair. We argue that, at least within our mean-field description, every cluster phase is supersolid.