Intermediate Mode Research Articles

Frequency-tuning-induced state transfer in optical microcavities

Quantum state transfer in optical microcavities plays an important role in quantum information processing and is essential in many optical devices such as optical frequency converters and diodes. Existing schemes are effective and realized by tuning the coupling strengths between modes. However, such approaches are severely restricted due to the small amount of strength that can be tuned and the difficulty performing the tuning in some situations, such as in an on-chip microcavity system. Here we propose a novel approach that realizes the state transfer between different modes in optical microcavities by tuning the frequency of an intermediate mode. We show that for typical functions of frequency tuning, such as linear and periodic functions, the state transfer can be realized successfully with different features. To optimize the process, we use the gradient descent technique to find an optimal tuning function for a fast and perfect state transfer. We also showed that our approach has significant nonreciprocity with appropriate tuning variables, where one can unidirectionally transfer a state from one mode to another, but the inverse direction transfer is forbidden. This work provides an effective method for controlling the multimode interactions in on-chip optical microcavities via simple operations, and it has practical applications in all-optical devices.

Design of TE01-to-HE11 mode converters for high-power millimeter wave applications at 35 GHz.

Based on the coupled wave theory, we have designed the TE01-HE11 high efficiency and high-power mode converter at 35 GHz through the method of numerical simulation, where the TM11 mode is used as the intermediate mode. The ohmic losses due to the metal walls are taken into account in the calculations, and rematching phase techniques are used to increase the conversion efficiency. Modeling analysis is performed using commercial CST Microwave Studio software, and the cold test is performed. Experimental results verify the accuracy of numerical simulation.

An extended edge-notched disc bend (ENDB) specimen for mixed-mode I+II fracture assessments

A new test specimen for mixed-mode I+II fracture studies is proposed. An extended version of edge notch disc bend (ENDB) specimen, which was recently proposed to assess mixed-mode I+III fracture toughness, is designed and developed for introducing opening-in-plane-shear sliding mode. This new specimen that is called asymmetric ENDB specimen (A-ENDB), was numerically analysed to determine the stress intensity factors and T-stress along the crack front for a wide range of geometric and loading conditions. The finite element results demonstrated that (i) the contribution of mode III component is negligible under asymmetric loading of ENDB specimen and; (ii) the full modes I and II mixities including pure mode I, pure mode II and intermediate mode mixities can be achieved by changing loading support distances. The capability of the proposed asymmetric ENDB specimen was then experimentally assessed by conducting several mixed-mode I+II fracture toughness tests on a brittle model polymer (PMMA). The mode II fracture toughness value obtained from the A-ENDB specimen was noticeably greater than KIc value. Although the fracture trajectory of all A-ENDB specimens was nearly self-similar and along the plane of initial crack, different fracture surface morphologies were observed for mixed-mode I+II. The fracture surface consists of mirror area and ridge markings. While, towards to pure mode II, both density and length of the ridge marking were increased. It is shown that by using the same shape test specimen, loading type, and test configuration, both mixed-mode I+II and I+III can be studied.

Modal shift in North Atlantic seasonality during the last deglaciation

Abstract. Changeover from a glacial to an interglacial climate is considered as transitional between two stable modes. Palaeoceanographic reconstructions using the polar foraminifera Neogloboquadrina pachyderma highlight the retreat of the Polar Front during the last deglaciation in terms of both its decreasing abundance and stable oxygen isotope values (δ18O) in sediment cores. While conventional isotope analysis of pooled N. pachyderma and G. bulloides shells shows a warming trend concurrent with the retreating ice, new single-shell measurements reveal that this trend is composed of two isotopically different populations that are morphologically indistinguishable. Using modern time series as analogues for interpreting downcore data, glacial productivity in the mid-North Atlantic appears limited to a single maximum in late summer, followed by the melting of drifting icebergs and winter sea ice. Despite collapsing ice sheets and global warming during the deglaciation, a second “warm” population of N. pachyderma appears in a bimodal seasonal succession, separated by the subpolar G. bulloides. This represents a shift in the timing of the main plankton bloom from late to early summer in a “deglacial” intermediate mode that persisted from the glacial maximum until the start of the Holocene. When seawater temperatures exceeded the threshold values, first the “cold” (glacial) then the “warm” (deglacial) populations of N. pachyderma disappeared, whilst G. bulloides with a greater tolerance to higher temperatures persisted throughout the Holocene to the present day in the midlatitude North Atlantic. Single-specimen δ18O of polar N. pachyderma reveals a steeper rate of ocean warming during the last deglaciation than appears from conventional pooled δ18O average values.

Runtime Efficiency-Accuracy Tradeoff Using Configurable Floating Point Multiplier

Many applications, such as machine learning and sensor data analysis, are statistical in nature and can tolerate some level of inaccuracy in their computation. Approximate computing is a viable method to save energy and increase performance by controllably trading off energy for accuracy. In this paper, we propose a tiered approximate floating point multiplier, called CFPU, which significantly reduces energy consumption and improves the performance of multiplication at a slight cost in accuracy. The floating point multiplication is approximated by replacing the costly mantissa multiplication step of the operation with lower energy alternatives. We process the data by using one of the three modes: a basic approximate mode, an intermediate approximate mode, or on the exact hardware, depending on the accuracy requirements. We evaluate the efficiency of the proposed CFPU on a wide range of applications including twelve general OpenCL ones and three machine learning applications. Our results show that using the first CFPU approximation mode results in $3.5\times $ energy-delay product (EDP) improvement, compared to a GPU using traditional floating point units (FPUs), while ensuring less than 10% average relative error. Adding the second mode further increases the EDP improvement to $4.1\times $ , compared to an unmodified FPU, for less than 10% error. In addition, our results show that the proposed CFPU can achieve $2.8\times $ EDP improvement for multiply operations as compared to state-of-the-art approximate multipliers.

Exploring the risk spillover effects between carbon market and electricity market: A bidimensional empirical mode decomposition based conditional value at risk approach

This study proposes a bidimensional empirical mode decomposition based conditional value at risk approach to explore the risk spillover effects between carbon market and electricity market. Firstly, bidimensional empirical mode decomposition is applied to decompose the pair of carbon and electricity prices into a series of simple modes with different frequencies. Secondly, conditional value at risk is used to capture the risk spillover effects between carbon market and electricity market at each frequency. The empirical results show that the risks of high frequency modes are higher than those of intermediate and low frequency modes. Carbon market has a positive risk spillover on electricity market, and electricity market has a negative risk spillover on carbon market. For high and low frequency modes, the risk spillover effects from carbon market to electricity market are positive, however those from electricity market to carbon market are negative. For intermediate frequency modes, there are bidirectional negative risk spillover effects between carbon market and electricity market.

A continuous-discrete approach for pre-design of flexible-base tall buildings with fluid viscous dampers

An equivalent coupled-two-beam (CTB) discrete model is presented to compute the dynamic response in time domain of flexible-base buildings with linear fluid viscous dampers (FVDs). The equivalent model consists of a flexural cantilever beam and a shear cantilever beam connected in parallel by a finite number of axially rigid members that allows the consideration of intermediate modes of lateral deformation. The effects of different lateral deformations on the pre-design stage of two high-rise buildings are showed considering four soil types (hard rock, dense soil, stiff soil and soft soil) and three different distribution methods for linear FVDs: uniform-distribution (UD), story-shear-proportional-distribution (SSPD) and story-shear-strain-energy-distribution (SSSED). For UD method, the damping coefficients of FVDs increase as the flexural rigidity of the building decreases; whereas for SSPD and SSSED methods, the damping coefficients of FVDs vary along the height depending on the type of lateral deformation. For the three distribution methods and the same lateral deformation, the damping coefficients of FVDs decrease as the soil flexibility increases, which leads to a significant decrease in controlling earthquake-induced vibrations and wind-induced vibrations in the two high-rise buildings on a soft soil.

Effects of Climate Modes on Interannual Variability of Upwelling in the Tropical Indian Ocean

AbstractThis paper investigates interannual variability of the tropical Indian Ocean (IO) upwelling through analyzing satellite and in situ observations from 1993 to 2016 using the conventional Static Linear Regression Model (SLM) and Bayesian Dynamical Linear Model (DLM), and performing experiments using a linear ocean model. The analysis also extends back to 1979, using ocean–atmosphere reanalysis datasets. Strong interannual variability is observed over the mean upwelling zone of the Seychelles–Chagos thermocline ridge (SCTR) and in the seasonal upwelling area of the eastern tropical IO (EIO), with enhanced EIO upwelling accompanying weakened SCTR upwelling. Surface winds associated with El Niño–Southern Oscillation (ENSO) and the IO dipole (IOD) are the major drivers of upwelling variability. ENSO is more important than the IOD over the SCTR region, but they play comparable roles in the EIO. Upwelling anomalies generally intensify when positive IODs co-occur with El Niño events. For the 1979–2016 period, eastern Pacific (EP) El Niños overall have stronger impacts than central Pacific (CP) and the 2015/16 hybrid El Niño events, because EP El Niños are associated with stronger convection and surface wind anomalies over the IO; however, this relationship might change for a different interdecadal period. Rossby wave propagation has a strong impact on upwelling in the western basin, which causes errors in the SLM and DLM because neither can properly capture wave propagation. Remote forcing by equatorial winds is crucial for the EIO upwelling. While the first two baroclinic modes capture over 80%–90% of the upwelling variability, intermediate modes (3–8) are needed to fully represent IO upwelling.

Studying Operational Dynamics of Public Bus System: A Case of Lucknow City, India

In the era of rapid urbanization, the public bus system is struggling to become the main mode of transport in Indian cities. The co-existence of private city bus system and intermediate para-transit modes [shared auto-rickshaws, vikrams (6-8 seater shared 3-wheeler) and e-rickshaws] has created more competition for the public bus system instead of complementing it. This paper discusses the existing institutional arrangement of public bus systems in Lucknow city and identifies the challenges of organizations to operate an efficient public bus system. The study is based on primary survey and structured interviews of public bus service operators, representatives of private bus operators, representatives of employee unions, auto-rickshaw & vikram drivers, officials of public transport authority and Regional Transport Office (RTO). The study explores public bus governance system and administrative hierarchy of the city to understand its existing operational process. The role of travel cost and comfort in passenger’s choice of travel mode is discussed. The financial performance of the LCTSL shows the continuous losses. The paper contributes to identify the role of institutional framework to operate a successful public bus system. The analysis and findings will lead to the use of these modes in an integrated manner to complement and promote public bus system in a city.

How sustainable is the growth of mass transit system in developing countries – an Indian perspective

In the modern urban world, transport researchers and policy makers are vehemently emphasizing the use of mass transit modes, primarily due to their distinct advantage in achieving congestion reduction, and for being environment friendly. In order to achieve high mass transit ridership, it is necessary to attract people to such modes so as to make them appealing and attractive when compared to personal motorized modes of transport. At the same time, it is also vital to assess different mass transit improvement alternatives and adopt a policy that leads to the sustainable development. India is currently witnessing a proliferation of new urban mass rapid transit systems, even in non-metropolitan areas. These are expensive to build and often do not realize their full potential even after decades of operations. This begs the question – can operational service quality improvement alternatives of existing public transit, provide users with benefits, comparable to a new mass rapid transit system? This paper evaluates the probability of modal shift to bus mode from non-mass transit modes on introduction of different service improvement measures applicable to Indian context. A multinomial logit mode choice model was developed based on a revealed preference dataset consisting of users’ travel behavior in existing traffic scenario where three mass transit modes – suburban rail, subway/ metro rail & bus, as well as the intermediate public transit mode of auto-rickshaw, where available. The model is used to predict impacts of three major policies - (1) existing network improvement, (2) lane management and (3) introduction of bus rapid transit system in terms of level of service improvements of bus transit and bus transit mode share. Results show that improvement in existing bus transit is more beneficial compared to lane management strategy and even comparable to bus rapid transit system considering the cost and time budget which may be used as a policy making tool by authorities for future city planning.

Coupled‐two‐beam discrete model for dynamic analysis of tall buildings with tuned mass dampers including soil–structure interaction

SummaryAn equivalent coupled‐two‐beam discrete model is developed for time‐domain dynamic analysis of high‐rise buildings with flexible base and carrying any number of tuned mass dampers (TMDs). The equivalent model consists of a flexural cantilever beam and a shear cantilever beam connected in parallel by a finite number of axially rigid members that allows the consideration of intermediate modes of lateral deformation. The equivalent model is applied to a shear wall–frame building located in the Valley of Mexico, where the effects of soil–structure interaction (SSI) are important. The effects of SSI and TMDs on the dynamic properties of the shear wall–frame building are shown considering four types of soil (hard rock, dense soil, stiff soil, and soft soil) and two passive damping systems: a single TMD on its top (1‐TMD) and five uniformly distributed TMDs (5‐TMD). The results showed a great effectiveness of the TMDs to reduce the lateral seismic response and along‐wind response of the shear wall–frame building for all types of soils. Generally speaking, the dynamic response increases as the flexibility of the foundation increases.

The Extent of Social Contribution of Venture Capital Organisations to Funded Financed Companies

The major objective lying behind the conduction of the present work lies in investigating the social advantages likely to be brought about by the venture capitalist to the funded firm. More specially, it treats the venturer’s financial contribution as based on a number of human resources management related practices. Overall, the reached results, relevant to a sample involving 150 companies proved to indicate that the financial participation of this mode of financial intermediation turns out to be partially associated with a social contribution. In effect, it has been discovered that a number of the advanced practices, suggested as social contribution relating measures, do not prove to stand as part of the changes targeted by the venture capitalist to take place in a bid to enhance the firm’s social performance, nor were they intended to further improve the added values already achieved. Actually, such a strategy could well reflect some special features characterize the Tunisian venture capital mode of financing.

Recent advances in the physics of polymer systems

Recent advances in the physics of polymer systems

Coupled shear‐flexural model for dynamic analysis of fixed‐base tall buildings with tuned mass dampers

SummaryAn equivalent discrete model is developed for time domain dynamic analysis of uniform high‐rise shear wall‐frame buildings with fixed base and carrying any number of tuned mass dampers (TMDs). The equivalent model consists of a flexural cantilever beam and a shear cantilever beam connected in parallel by a finite number of axially rigid members that allow the consideration of intermediate modes of lateral deformation. The proposed model was validated by a building whose lateral resisting system consists of a combination of shear walls and braced frames. The results showed the effectiveness of TMDs to reduce the peak displacements, interstory drift ratio, and accelerations when the building is subjected to a seismic load. The root mean square accelerations due to along‐wind loads also decrease if TMDs are attached to the building.

Rigorous Justification of Taylor Dispersion via Center Manifolds and Hypocoercivity

Taylor diffusion (or dispersion) refers to a phenomenon discovered experimentally by Taylor in the 1950s where a solute dropped into a pipe with a background shear flow experiences diffusion at a rate proportional to $1/\nu$, which is much faster than what would be produced by the static fluid if its viscosity is $0 < \nu \ll 1$. This phenomenon is analyzed rigorously using the linear PDE governing the evolution of the solute. It is shown that the solution can be split into two pieces, an approximate solution and a remainder term. The approximate solution is governed by an infinite-dimensional system of ODEs that possesses a finite-dimensional center manifold, on which the dynamics correspond to diffusion at a rate proportional to $1/\nu$. The remainder term is shown to decay at a rate that is much faster than the leading order behavior of the approximate solution. This is proven using a spectral decomposition in Fourier space and a hypocoercive estimate to control the intermediate Fourier modes.

Controllable optical response in a three-mode optomechanical system by driving the cavities on different sidebands.

We study the controllable optical response in a three-mode optomechanical system comprised of two indirectly coupled cavity modes and an intermediate mechanical mode. The two cavity modes are assumed to have different frequencies and driven by two control fields on the red and blue sidebands, respectively. When the system is perturbed by two probe fields satisfying the specific matching condition, a series of intriguing phenomena can be observed by adjusting phases and amplitudes of the control fields, such as absorption-amplification switching, ultra-narrow response windows, frequency-independent perfect reflection, and ultralong optical group delay. We also compare our system with conventional optomechanical systems to highlight its distinct features. Our results may have potential applications in optical communication and quantum information processing.

Effect of Alternating Electric Current on Pulsation Mode of Rat Major Arteries In Situ.

In experiments on narcotized rats, the electrical potential and impedance of isolated segment of the right femoral and/or carotid artery were simultaneously recorded in situ via two extracellular nonpolarizable Ag/AgCl electrodes mounted along the arteries at the interelectrode distance of 4 mm. The active, passive, and intermediate pulsing modes of arterial segment were determined according to the phase relations between its electrical impedance and BP, which was simultaneously measured in the symmetrical part of the respective left artery and used to assess pressure in the examined segment. The study assessed the effect of amplitude (0.2-2.0 mA) of alternating probe current (100 kHz), which was used to measure the electrical impedance of arterial segment, on its pulsing mode. The pulsing mode determined at the initial minimal probe current of 0.2 mA was passive with out-of-phase pulsatile oscillations of electrical impedance and BP. After elevation of the probe current amplitude to maximal level of 2 mA, these oscillations became in-phase indicating transition of the arterial segment to active pulsing mode. This transition was accompanied by appearance of arterial voltage impulses synchronized with BP upstrokes and an 11-fold median increase in the peak-to-peak value of electrical impedance oscillations with the interdecile range of 7-15 (N=28). Under moderate amplitude of probe current (0.3-0.5 mA), the intermediate mode of arterial pulsing was observed featured by a delayed, weak, and short active constriction during BP front, which was insufficient to resist and counterbalance the dilating effect of rising BP. In this case, the pulsatile oscillations of electrical impedance were smaller than those observed in active or passive pulsing modes indicating a possibility to stabilize the arterial diameter during pulsatile oscillations of BP. The effect of alternating electric current on the mode of arterial pulsation is explained with electrical model of smooth muscle cell membrane reflecting the rectifying features of potassium channels and predicting membrane hyperpolarization in response to external alternating current passing across the cell. The visibilities of therapeutic neurotropic and angiotropic stimulation with alternating electric current are discussed.

Deformation and dynamics of erythrocytes govern their traversal through microfluidic devices with a deterministic lateral displacement architecture.

Deterministic lateral displacement (DLD) microfluidic devices promise versatile and precise processing of biological samples. However, this prospect has been realized so far only for rigid spherical particles and remains limited for biological cells due to the complexity of cell dynamics and deformation in microfluidic flow. We employ mesoscopic hydrodynamics simulations of red blood cells (RBCs) in DLD devices with circular posts to better understand the interplay between cell behavior in complex microfluidic flow and sorting capabilities of such devices. We construct a mode diagram of RBC behavior (e.g., displacement, zig-zagging, and intermediate modes) and identify several regimes of RBC dynamics (e.g., tumbling, tank-treading, and trilobe motion). Furthermore, we link the complex interaction dynamics of RBCs with the post to their effective cell size and discuss relevant physical mechanisms governing the dynamic cell states. In conclusion, sorting of RBCs in DLD devices based on their shear elasticity is, in general, possible but requires fine-tuning of flow conditions to targeted mechanical properties of the RBCs.

Timing and the transition between modes in the defensive behavior system

Antipredator defense is organized in a way that mirrors Timberlake’s feeding behavior system because the goal of defense is to thwart predatory behavior. Each predatory mode has a corresponding antipredator mode. Like appetitive behavior systems, the defensive behavior system is organized around distinct modes along a spatiotemporal continuum we call the predatory imminence continuum. Behavior systems theory directs investigation toward the factors that lead to transitions between modes. In the feeding and sex systems the time between Conditional Stimulus (CS) and Unconditional Stimulus (US; e.g., CS-US interval or CS duration) is an important factor. Short CSs elicit conditional responses (CR) characteristic of more terminal modes and long CSs provoke CRs belonging to initial modes. Therefore, we asked if short CSs (10 s) would provoke CRs like the vigorous activity bursts and escape-like responses characteristic of the terminal mode of the predatory imminence continuum (Circa-Strike Behavior). Also, via analogy to appetitive systems, long CSs (3 min) were predicted to favor the intermediate mode, post-encounter behavior, which is characterized by freezing. Instead we found that both CSs produced freezing but not activity burst CRs and that freezing was actually greater with the short CS. We suggest that this difference between behavior systems flows from selection pressure that favors moving toward terminal modes in appetitive systems but away from terminal modes in the antipredator system. In addition, since appetitive reinforcers are more likely to be repeatedly experienced than predators, the learning of timing may be less relevant to defense. We also found that shock produced activity bursts and argue that when you are in the post-encounter mode (freezing) a sudden change in stimulation causes an immediate transition to circa-strike (terminal) behavior.

Speed-Invariant Gait Recognition Using Single-Support Gait Energy Image

Gait is one of the most popular behavioral biometrics because it can be authenticated at a distance from a camera without subject cooperation. Speed differences between matching pairs, however, cause significant performance drops in gait recognition, and gait mode difference (i.e., walking versus running) makes gait recognition further challenging. We therefore propose a speed-invariant gait representation called single-support GEI (SSGEI), which realizes a good trade-off between speed invariance and stability by aggregating multiple frames around single-support phases. In addition, to mitigate the pose differences between walking and running modes at single-support phases, we morph walking and running SSGEIs into intermediate SSGEIs between walking and running mode, where we exploit a free-form deformation field from the walking or running modes to the intermediate mode obtained by training data. We finally apply Gabor filtering and spatial metric learning as postprocessing for further accuracy improvement. Experiments on two publicly available datasets, the OU-ISIR Treadmill Dataset A and the CASIA-C Dataset demonstrate that the proposed method yields the state-of-the-art accuracies in both identification and verification scenarios with a low computational cost.