Asymmetric Paths Research Articles

A method of designing asymmetric double-sided off-axis aspheric mirror detection compensation zoom light path

With the development of multispectral common-aperture high-precision detection technology, the asymmetric double-sided off-axis aspheric mirror is playing an increasingly important role in characterizing the correcting phase difference, increasing the relative caliber of system, expanding the view angle of field, simplifying system structure, and reducing weight and volume. But high-precision detection is a key step restricting the applications of these mirrors. At present, the compensation method of the interference test is the most effective mean of off-axis aspheric surface detection which has a simple structure, large compensation range, small number of components and is easy to control. However for the detection of asymmetric double-sided off-axis aspheric mirrors, two sets of alone compensators are still used, in which the efficiency is low and the switching compensator will reduce the accuracy of detection. Aiming at this problem, in this paper we propose a zoom null compensation method which is based on the Offner refracting compensation method. In this method, the off-axis aperture stop causes the light to be off-axis and split, the common lens group is moved to zoom, and the mirror folds the light path. There are two off-axis apertures are provided for off-axis and splitting, four lenses which form three lens groups are used to move positions for zooming, two mirrors are used to fold light. An optical design software is used to simulate the experiment, and implements the design for the high-precision detection of optical path for the asymmetric double-sided off-axis aspherical mirror by using this set of null compensation method. The simulation result shows that the theoretical residual wave aberration increases up to 0.0003λ root-mean-square (RMS) and 0.0001λ RMS with the designed system compensation, which meet the requirement for detection. At the same time, the tolerance analysis is carried out according to the design result, the actual residual wave aberrations within the existing tolerance range are 0.0326λ RMS and 0.0316λ RMS, which meet the requirements for manufacturing and assembly. The present work provides a new idea for the high-precision detection of asymmetric double-sided off-axis aspheric mirror. At the same time, the quality of the detected beam in this paper is achieved under ideal conditions, and the quality of beam will be considered in the next research work.

LinkScope: Toward Detecting Target Link Flooding Attacks

A new class of target link flooding attacks (LFAs) can cut off the Internet connections of a target area without being detected, because they employ legitimate flows to congest selected links. Although new mechanisms for defending against LFA have been proposed, the deployment issues limit their usage, since they require either additional modules to enhance routers or using the software-defined network to replace the traditional routers. In this paper, we propose a novel framework that employs both the end-to-end and hop-by-hop network measurement techniques to capture the abnormal path performance degradation for detecting LFA and then locate the target links or areas whenever possible, and develop a prototype of the framework named LinkScope . Although using network measurement to capture network anomaly is not new, we tackle a number of challenging issues, such as conducting large-scale Internet path monitoring via non-cooperative measurement so that users do not need to install LinkScope on every host, profiling the performance of asymmetric Internet paths and detecting LFA. The extensive evaluation in a testbed and the Internet shows that with limited bandwidth and computational overhead, LinkScope can achieve timely detection and diagnosis of LFA with high detection rate and low false positive rate.

Path Following in Non-Visual Conditions

Path-following tasks have been investigated mostly under visual conditions, that is when subjects are able to see both the path and the tool, or limb, used for navigation. Moreover, only basic path shapes are usually adopted. In the present experiment, participants must rely exclusively on continuous, non-speech, and ecological auditory and vibrotactile cues to follow a path on a flat surface. Two different, asymmetric path shapes were tested. Participants navigated by moving their index finger over a surface sensing position and force. Results show that the different non-visual feedback modes did not affect the task's accuracy, yet they affected its speed, with vibrotactile feedback causing the slowest gestures. Also, vibrotactile feedback caused participants to exert more force over the surface. Finally, the shape of the path was relevant to the accuracy, and participants tended to prefer audio over vibrotactile and audio-tactile feedback.

Vapor nucleation paths in lyophobic nanopores

.In recent years, technologies revolving around the use of lyophobic nanopores gained considerable attention in both fundamental and applied research. Owing to the enormous internal surface area, heterogeneous lyophobic systems (HLS), constituted by a nanoporous lyophobic material and a non-wetting liquid, are promising candidates for the efficient storage or dissipation of mechanical energy. These diverse applications both rely on the forced intrusion and extrusion of the non-wetting liquid inside the pores; the behavior of HLS for storage or dissipation depends on the hysteresis between these two processes, which, in turn, are determined by the microscopic details of the system. It is easy to understand that molecular simulations provide an unmatched tool for understanding phenomena at these scales. In this contribution we use advanced atomistic simulation techniques in order to study the nucleation of vapor bubbles inside lyophobic mesopores. The use of the string method in collective variables allows us to overcome the computational challenges associated with the activated nature of the phenomenon, rendering a detailed picture of nucleation in confinement. In particular, this rare event method efficiently searches for the most probable nucleation path(s) in otherwise intractable, high-dimensional free-energy landscapes. Results reveal the existence of several independent nucleation paths associated with different free-energy barriers. In particular, there is a family of asymmetric transition paths, in which a bubble forms at one of the walls; the other family involves the formation of axisymmetric bubbles with an annulus shape. The computed free-energy profiles reveal that the asymmetric path is significantly more probable than the symmetric one, while the exact position where the asymmetric bubble forms is less relevant for the free energetics of the process. A comparison of the atomistic results with continuum models is also presented, showing how, for simple liquids in mesoporous materials of characteristic size of ca. 4nm, the nanoscale effects reported for smaller pores have a minor role. The atomistic estimates for the nucleation free-energy barrier are in qualitative accord with those that can be obtained using a macroscopic, capillary-based nucleation theory.Graphical abstract

Estimation Theory-Based Robust Phase Offset Determination in Presence of Possible Path Asymmetries

This paper addresses the problem of robust clock phase offset estimation for the IEEE 1588 precision time protocol in the presence of unknown asymmetric network path delays. The presence of an unknown asymmetry between the path delays can lead to significant degradation in the performance of a phase offset estimation scheme. Assuming multiple master-slave communication paths are available, we first provide lower bounds on the best achievable performance for a phase offset estimation scheme in the presence of asymmetric master-slave communication paths. We then present a novel phase offset estimation scheme that employs the expectation-maximization algorithm to identify the asymmetric master–slave communication paths. After discarding information from these paths, we employ the minimax optimum vector location parameter estimator for estimating the phase offset. Simulation results are presented to show that the proposed phase offset estimation scheme exhibits performance close to the lower bounds in a wide variety of network scenarios.

Perceptional components of brand equity: Configuring the Symmetrical and Asymmetrical Paths to brand loyalty and brand purchase intention

This research investigates the impact of brand perception on brand loyalty and brand purchase intention using the lenses of complexity theory. First, the study conceptualizes and operationalizes perceptional and behavioral components of brand equity. It then examines the dimensions of brand perception, and by assessing the consequences of favorable brand perception, the study enables a better understanding regarding whether a brand marketing approach helps to improve marketing performance. The research was conducted using a mixed methodology, beginning with interviews in order to gain a better understanding of the relationship between the dimensions of brand perception. These were followed by a questionnaire survey, and the resulting data were analyzed through content analysis and fuzzy-set qualitative comparative analysis (fsQCA). The results indicate that brand awareness, perceived quality, brand association, brand fondness, brand image, and product country image have a strong impact on the management of brand perception. The finding illustrates that it is the combinations of various perceptional elements of brand equity rather than any single factor that have strong impacts on brand loyalty and brand purchasing intention. The results support the importance of brand perception for the fashion industry, which needs to be more interactive in order to increase their customers' brand loyalty and brand purchasing intention.

Experimental investigation of SRHSC columns under biaxial loading

The behavior of 8 steel reinforced high-strength concrete (SRHSC) columns, which comprised of four identical columns with cross-shaped steel and other four identical columns with square steel tube, was investigated experimentally under cyclic uniaxial and biaxial loading independently. The influence of steel configuration and loading path on the global behavior of SRHSC columns in terms of failure process, hysteretic characteristics, stiffness degradation and ductility were investigated and discussed, as well as stress level of the longitudinal and transverse reinforcing bars and steel. The research results indicate that with a same steel ratio deformation capacity of steel reinforced concrete columns with a square steel tube is better than the one with a cross-shaped steel. Loading path affects hysteretic characteristics of the specimens significantly. Under asymmetrical loading path, hysteretic characteristics of the specimens are also asymmetry. Compared with specimens under unidirectional loading, specimens subjected to bidirectional loading have poor carrying capacity, fast stiffness degradation, small yielding displacement, poor ductility and small ultimate failure drift. It also demonstrates that loading paths affect the deformation capacity or deformation performance significantly. Longitudinal reinforcement yielding occurs before the peak load is attained, while steel yielding occurs at the peak load. During later displacement loading, strain of longitudinal and transverse reinforcing bars and steel of specimens under biaxial loading increased faster than those of specimens subjected to unidirectional loading. Therefore, the bidirectional loading path has great influence on the seismic performance such as carrying capacity and deformation performance, which should be paid more attentions in structure design.

A heuristic for a heterogeneous automated guided vehicle routing problem

The article addresses a Heterogeneous Automated Guided Vehicle (AGV) Routing Problem that distributes given jobs to one of the AGVs and finds a route for each AGV while minimizing the sum of tour costs. AGVs are heterogeneous as the cost of traveling between any two locations varies depending on the type of AGV. The problem is a generalization of multiple heterogeneous asymmetric Hamiltonian path problem and a primal-dual heuristic has been developed. Despite the complexity of the problem, the computational results show that the proposed algorithm produces good quality solutions within a relatively short computation time.

The Deteriorating Dynamics of Public Debts Across Countries within the European Monetary Unification in Comparison with Countries Outside the European Monetary

The main aim of this study is to analyze the evolution of public debts and general government deficits/surplus across European countries within and outside the monetary unification. In particular, this study compares the dynamics of public debts and general government deficits between European countries within and outside the monetary unification for the preceding and subsequent period the introduction of the Euro currency. Statistical analyses show that the evolution of public debts is significantly different between European countries. Nations within the European monetary unification seem to have, from 2001 onwards, a deteriorated sovereign debts and general government deficits in comparison to countries outside the European monetary unification. This dissimilar evolution of public debts and general government deficits between European countries can be due to manifold factors. Moreover, these asymmetric paths of public debts and general government deficits across European countries may be one of contributing factors that generates uncertain scenarios and negative socioeconomic effects on patterns of growth of the overall European Union economy.

Asymmetric paths of public debts and of general government deficits across countries within and outside the European monetary unification and economic policy of debt dissolution

The aim of this study is to analyze the evolution of public debts and of government deficits/surplus across European countries within and outside the monetary unification. In particular, this study compares the dynamics of public debts and of general government deficits between European countries within and outside the monetary unification for the preceding and subsequent period the introduction of the Euro currency. Statistical analyses show that the evolution of public debts and government deficits/surplus is significantly different between European countries. Nations within the European monetary unification seem to have, from 2001, deteriorated trends of sovereign debts and government deficits in comparison with countries outside the European monetary unification. This dissimilar evolution of public debts and of government deficits between European countries can be due to manifold factors. These asymmetric paths of public debts and of government deficits across European countries may be one of contributing factors that generates uncertain scenarios and negative socioeconomic effects on patterns of growth of the overall European Union economy. A economic policy of debt dissolution is suggested.

Receiver-centric Buffer Blocking-aware Multipath Data Distribution in MPTCP-based Heterogeneous Wireless Networks

One major concern of applying Multipath TCP (MPTCP) to data delivery in heterogeneous wireless networks is that the utilization of asymmetric paths with diverse networking-related parameters may cause severe packet reordering and receive buffer blocking (RB2LOC). Although many efforts are devoting to addressing MPTCP`s packet reordering problems, their sender-controlled solutions do not consider balancing overhead between an MPTCP sender and receiver, and their fully MPTCP mode cannot make MPTCP achieve a desired performance. This paper proposes a novel receiver-centric buffer blocking-aware data scheduling strategy for MPTCP (dubbed MPTCP-rec) necessitating the following aims: (1) alleviating MPTCP`s packet reordering and RB2LOC problems, (2) improving the MPTCP performance, and (3) balancing load between the MPTCP sender and receiver. Simulation results show that the proposed MPTCP-rec solution outperforms the existing MPTCP solutions in terms of data delivery performance in heterogeneous wireless networks.

Avoiding interpenetrations and the importance of nesting in analytic geometry construction for Representative Unit Cells of woven composite laminates

A novel method for geometry generation of Representative Unit Cells (RUC) of textile composites is presented. The technique retains the advantage of an analytical formulation from industrial practice however introduces variable asymmetric yarn cross-sectional shapes and paths which can be fitted to the yarn shapes and cross-sectional areas as observed from in-situ measurements. In this way interpenetrations and incorrect fibre volume fractions, which occur when using idealized constant yarn cross sections for RUC generation, are avoided. Meshing becomes easier and no fibre volume corrections are required. The new technique is validated through a comparison of 1) the novel RUC to 2) an Idealized RUC with constant yarn cross section; and 3) a model constructed from direct in-situ micro computed X-ray tomographic measurements of a carbon-epoxy weave (In-situ Model). With all three models a reasonable agreement with experimentally obtained elastic properties is found. The stress predicted by the Idealized RUC is significantly different than predicted by the RUC generated with the new method and the In-situ Model. The latter two are in good agreement which indicates that the MESI RUC can be used for material strength prediction. The MESI RUC is also substantially less computationally intensive. Next to the construction of improved RUCs, the technique is an excellent alternative for advanced unit cell generation techniques based on production process simulations in the case that the production process is unknown or an analytic periodic geometry is required.

Asymmetric Reaction Paths and Hydrogen Sorption Mechanism in Mechanochemically Synthesized Potassium Alanate (KAlH4)

KAlH4 is the unique monoalkali alanate that absorbs hydrogen reversibly with reasonable kinetics at moderate pressures without doping, offering an exciting playground to understand the role of addi...

Asymmetric toroidal eddy currents (ATEC) to explain sideways forces at JET

During some JET vertical displacement events (VDEs) plasma current and position are found to be toroidally asymmetric. When asymmetries lock, the vessel has been observed to move horizontally, consequently strong horizontal forces are expected following plasma asymmetries, whether locked or rotating. The cause of horizontal forces is, as already identified in previous works, the asymmetric circulation of current in the structures. The physics mechanism responsible for these asymmetric currents is instead an open issue and it is the object of the present analysis. In particular it will be shown that the asymmetry is not due to a direct exchange of current between plasma and structure (as in the case of halo currents) but to asymmetric conductive paths which arise, in the structures, when the plasma column asymmetrically wets the wall. Simulations of this phenomenon using finite element (FE) models have been conducted to reproduce the JET observation during locked and rotating asymmetric VDEs. Estimated sideways force, asymmetry () and normalized asymmetry () of plasma current, vertical position at different toroidal locations during the disruption and halo current asymmetry have been compared with measurements done at JET during upward AVDEs. The substantial match between experiments and simulations confirms the soundness of the assumptions. Furthermore, the same physical model applied to downward VDEs shows that divertor support and coils, together with the geometry of the limiting surfaces, considerably lessen asymmetric loads as experienced at JET after installing those components.

An Improved Integrality Gap for Asymmetric TSP Paths

The asymmetric traveling salesperson path problem (ATSPP) is one where, given an asymmetric metric space (V, d) with specified vertices s and t, the goal is to find an s-t path of minimum length that passes through all the vertices in V. This problem is closely related to the asymmetric TSP (ATSP), which seeks to find a tour (instead of an s-t path) visiting all the nodes: for ATSP, a ρ-approximation guarantee implies an O(ρ)-approximation for ATSPP. However, no such connection is known for the integrality gaps of the linear programming (LP) relaxations for these problems: the current-best approximation algorithm for ATSPP is O(ln n/ln ln n), whereas the best bound on the integrality gap of the natural LP relaxation (the subtour elimination LP) for ATSPP is O(ln n). In this paper, we close this gap, and improve the current best bound on the integrality gap from O(ln n) to O(ln n/ln ln n). The resulting algorithm uses the structure of narrow s-t cuts in the LP solution to construct a (random) tree spanning tree that can be cheaply augmented to contain an Eulerian s-t walk. We also build on a result of Oveis Gharan and Saberi and show a strong form of Goddyn’s conjecture about thin spanning trees implies the integrality gap of the subtour elimination LP relaxation for ATSPP is bounded by a constant. Finally, we give a simpler family of instances showing the integrality gap of this LP is at least 2.

Evolution of supercurrent path inNb/Ru/Sr2RuO4dc-SQUIDs

Phase-sensitive measurements of direct-current superconducting quantum interference devices (dc-SQUIDs) composed of ${\mathrm{Sr}}_{2}{\mathrm{RuO}}_{4}$-Ru eutectic crystals have been performed to temperatures below a bulk Ru superconducting transition temperature at 0.49 K. A SQUID with $\mathrm{Nb}/\mathrm{Ru}/{\mathrm{Sr}}_{2}{\mathrm{RuO}}_{4}$ junctions fabricated on one Ru inclusion exhibits two distinct transitions due to the Ru superconducting transition and competition of proximity-induced superconducting gaps at the junctions. At sufficiently low temperatures, the SQUID interference patterns start to collapse with large phase shifts of the Fraunhofer patterns. This result indicates the influence of magnetic fluxes induced by large bias currents flowing in a strongly asymmetric supercurrent path. Such a large change in supercurrent path suggests superconducting phase mismatch between the $s$-wave and chiral $p$-wave states at the $\mathrm{Ru}/{\mathrm{Sr}}_{2}{\mathrm{RuO}}_{4}$ interface.

Single-edge transport in an InAs/GaSb quantum spin Hall insulator

We report transport measurements in a single edge channel of an InAs/GaSb quantum spin Hall insulator, where the conduction occurs through only one pair of counterpropagating edge modes. By using a specific sample design involving highly asymmetric current paths, we electrically isolate a single edge channel of the two-dimensional topological insulator from the other edge. This enables us to probe a single edge by multiterminal measurements. Both two-terminal and four-terminal resistances show a nearly quantized plateau around $h/e^2$ for a 4-$\mu$m-long edge, indicating quasiballistic transport. Our approach is advantageous in that it allows us to gain insight into a microscopic region from local measurements.

Minimum Delay Query in Low-duty-cycle Sensor Networks

Data query is a common communication pattern in sensor networks. However, due to the introduction of sleep latency, it is challenging to perform efficient query in low-dutycycle sensor networks. In particular, the round-trip delay from the sink to source nodes and vice versa over the same forwarding path could be extremely long. In this work, westudy the delay optimization problem by jointly considering routing and sleep scheduling, then propose a holistic scheme to find the asymmetric routing paths for data query and response so that the round-trip delay could be minimized. We compared ourMinimum Delay Query (MDQ) deign with the state-of-the-art schemes. The evaluation results verify that our design can greatly reduce the query delay in low-duty-cycle sensor networks.

Collective modes in multipolar plasmonic lattices: control of interparticle-gap upward/downward energy streams

We numerically study the collective resonances and field profiles of two-dimensional arrays of large metallic nanodisks supporting multipolar plasmonic modes in nearly homogeneous environments. We show that, depending on the wavelength, these arrays can support two distinct collective modes with orthogonal field intensity distributions. In one of these modes (scattering mode), the optical scattering between the nanodisks forms a sharp optical feature with significant sensitivity to the refractive index of the environment. In the second mode (optical-band mode), the nanodisks are mainly coupled via an optical band with a field intensity profile perpendicular to the incident light polarization. This mode is associated with a subtle optical peak with much less sensitivity to the environment. We demonstrate that around this peak, the nanodisks support a unique asymmetrical field dispersion and energy flow paths. For a given wavelength range, the plasmon fields in this mode deeply penetrate into the substrate while energy moves up from the substrate between the gaps of the nanodisks, forming energy whirlpools in the superstrate. With a slight wavelength change, these fields switch to the superstrate, and the direction of the gap energy path is inverted. We investigate how such features can be tuned by adding a thin layer of silicon between the substrate and superstrate and discuss the applicability of the scattering mode for sensitive sensors.

Is multi-path transport suitable for latency sensitive traffic?

This paper assesses whether multi-path communication can help latency-sensitive applications to satisfy the requirements of their users. We consider Concurrent Multi-path Transfer for SCTP (CMT-SCTP) and Multi-path TCP (MPTCP) and evaluate their proficiency in transporting video, gaming, and web traffic over combinations of WLAN and 3G interfaces. To ensure the validity of our evaluation, several experimental approaches were used including simulation, emulation and live experiments. When paths are symmetric in terms of capacity, delay and loss rate, we find that the experienced latency is significantly reduced, compared to using a single path. Using multiple asymmetric paths does not affect latency – applications do not experience any increase or decrease, but might benefit from other advantages of multi-path communication. In the light of our conclusions, multi-path transport is suitable for latency-sensitive traffic and mature enough to be widely deployed.