May T. Lim
Sex: Female
Education:
Doctor of Philosophy in Physics, University of the Philippines, 2003
Field of Specialization
Computational statistical physics (Monte Carlo methods, agent-based models, networks)
Researches:
Article title: Modeling the residential distribution of enrolled students to assess boundary-induced disparities in public school access
Authors: Louie John M. Rubio, Damian N. Dailisan, Maria Jeriesa P. Osorio, Clarissa C. David, et al.
Publication title: PloS one 14(10), 2019
Abstract:
Given school enrollments but in the absence of a student residence census, we present a gravity-like model to infer the residential distribution of enrolled students across various administrative units. Multi-scale analysis of the effects of aggregation across different administrative levels allows for the identification of administrative units with sub-optimally located schools and highlights the challenges in allocating resources. Using this method, we verify that the current scheme of free cross-enrollment across administrative boundaries is needed in achieving universal education in the Philippines.
Article title: Vehicular traffic modeling with greedy lane-changing and inordinate waiting
Authors: Damian N. Dailisan and May T. Lim
Publication title: Physica A: Statistical Mechanics and its Applications 521: 715-723, 2019
Abstract:
Lane changing and vehicular slowdowns are known to impact traffic flow. Using a modified Nagel–Schreckenberg cellular automata model for two vehicle types: blocking (eg cars) and non-blocking (eg motorcycles), we determined the thresholds at which the interplay of lane changing, random and non-random slowdowns strongly impact vehicle speeds. Lane changing improves speed with diminishing returns as vehicles opt to change lanes. At the same time, lane changing is detrimental to the overall speed when lane straddling occurs. Increasing random slowdowns beyond a critical value (in the case of motorcycles, slowdown values of p slow≈[0. 2, 0. 3, 0. 4] for densities ρ=[0. 20, 0. 15, 0. 10] respectively) can force crossover from free flowing traffic into a state where interactions between vehicles reduce the average speed.
Full text available upon request to the author
Article title: Agent-based modeling of lane discipline in heterogeneous traffic
Authors: Damian N. Dailisan and May T. Lim
Publication title: Physica A: Statistical Mechanics and its Applications 457: 138-147, 2016
Abstract:
Designating lanes for different vehicle types is ideal road safety-wise. Practical considerations, however, require road sharing. Using a modified Nagel–Schreckenberg cellular automata model for two vehicle types (cars and motorcycles), we analyzed the interplay of lane discipline, lane changing, and vehicle density. In the absence of lane changing, the transition between free flow and congested states occurs at a higher vehicle (road occupation) density when the ratio of cars to motorcycles is increased. When lane changing is allowed, the smaller motorcycles tend to fill in unused spaces, until the point when the wider cars effectively block their way at high vehicle densities. When the condition of lane discipline is not imposed, i.e. staying wholly within lane boundaries is not required, further improvement in throughput becomes possible at the cost of required driver attentiveness.
Article title: Siting marine protected areas based on habitat quality and extent provides the greatest benefit to spatially structured metapopulations
Authors: Reniel B. Cabral, Steven D. Gaines, May T. Lim, Michael P. Atrigenio, et al.
Publication title: Ecosphere 7(11): e01533, 2016
Abstract:
Connectivity and its role in the persistence and sustainability of marine metapopulations are attracting increased attention from the scientific community and coastal resource managers. Whether protection should prioritize the connectivity structure or demographic characteristics of a given patch is still unclear. We design a three‐stage population model to analyze the relative importance of sources, sinks, quality and extent of juvenile and adult habitat, and node centralities (eigenvector, degree, closeness, and betweenness) as a basis for prioritizing sites. We use a logistic‐type stage‐structured model to describe the local dynamics of a population with a sessile adult stage and network models to elucidate propagule‐exchange dynamics. Our results show that the coupled states of habitat extent and quality, which determine population carrying capacity, are good criteria for protection strategy. Protecting sites on the basis of sources, sinks, or other centrality measures of connectivity becomes optimal only in limited situations, that is, when larval production is not dependent on the adult population. Our findings are robust to a diverse set of larval pathway structures and levels of larval retention, which indicates that the network topology may not be as important as carrying capacity in determining the fate of the metapopulation. Protecting extensive, good quality habitat can help achieve both conservation and fisheries objectives.
Article title: Growing the physics community in the Philippines in a changing landscape
Authors: May T. Lim, Jose Perico H. Esguerra
Publication title: AIP Conference Proceedings 1697(1): 060037, 2015
Abstract:
Since the participation of the Philippines in the 3rd IUPAP International Conference on Women in Physics in 2008, the biggest change in the environment has happened online: Social media use is now pervasive. After the change in country leadership in 2010, policy directions were taken that directly affected the science research agenda, which in turn changed the research funding landscape. The uptake of government scholarship support for physics degrees continues to be popular with bachelor’s and master’s students regardless of gender. The country has also adopted the K–12 education system, and its impact on university employment remains to be seen.
Article title: Quantifying regional differences in the length of Twitter messages
Authors: Christian M. Alis, May T. Lim, Helen Susannah Moat, Daniele Barchiesi, et al.
Publication title: PloS one 10(4): e0122278, 2015
Abstract:
The increasing usage of social media for conversations, together with the availability of its data to researchers, provides an opportunity to study human conversations on a large scale. Twitter, which allows its users to post messages of up to a limit of 140 characters, is one such social media. Previous studies of utterances in books, movies and Twitter have shown that most of these utterances, when transcribed, are much shorter than 140 characters. Furthermore, the median length of Twitter messages was found to vary across US states. Here, we investigate whether the length of Twitter messages varies across different regions in the UK. We find that the median message length, depending on grouping, can differ by up to 2 characters.
Article title: Modelling the impacts of fish aggregating devices (FADs) and fish enhancing devices (FEDs) and their implications for managing small-scale fishery
Authors: Reniel B. Cabral, Porfirio M. Aliño, May T. Lim
Publication title: ICES Journal of Marine Science 71(7): 1750-1759, 2014
Abstract:
Fish aggregating devices (FADs) are deployed to aggregate fish over a limited area to improve fish catch. Fish enhancing devices (FEDs), which are FADs deployed in no-fishing areas, are fast gaining popularity as a fisheries management tool in the western Pacific. Yet, the impacts of utilizing FADs and FEDs are not yet well understood. In this work, we used a mean-field model to assess the effects of utilizing FADs and FEDs on stock biomass and catch. Our results indicate that using FADs enhances catch per boat when total fishing pressure is low, but can exacerbate fishery collapse when fishing effort is high. On the other hand, a FED-based system can increase the resistance of the fishery to collapse. A FED-based fishery may thus serve as pelagic marine protected areas and/or refugia. In a quota-based system, where fishing time is tied to catch quota, a phase transition occurs: both catch and biomass abruptly shift to low levels without warning. Deploying FADs to act as FEDs in a high quota fishery can prevent this phase transition resulting to a stabilizing effect.
Article title: Adaptation of fictional and online conversations to communication media
Authors: Christian M. Alis and May T. Lim
Publication title: European Physical Journal B 85(12), 2012
Abstract:
Conversations allow the quick transfer of short bits of information and it is reasonable to expect that changes in communication medium affect how we converse. Using conversations in works of fiction and in an online social networking platform, we show that the utterance length of conversations is slowly shortening with time but adapts more strongly to the constraints of the communication medium. This indicates that the introduction of any new medium of communication can affect the way natural language evolves.
Article title: Crowding effects in vehicular traffic
Authors: Jay Samuel L. Combinido and May T. Lim
Publication title: PloS one 7(11): e48151, 2012
Abstract:
While the impact of crowding on the diffusive transport of molecules within a cell is widely studied in biology, it has thus far been neglected in traffic systems where bulk behavior is the main concern. Here, we study the effects of crowding due to car density and driving fluctuations on the transport of vehicles. Using a microscopic model for traffic, we found that crowding can push car movement from a superballistic down to a subdiffusive state. The transition is also associated with a change in the shape of the probability distribution of positions from a negatively-skewed normal to an exponential distribution. Moreover, crowding broadens the distribution of cars’ trap times and cluster sizes. At steady state, the subdiffusive state persists only when there is a large variability in car speeds. We further relate our work to prior findings from random walk models of transport in cellular systems.
Article title: Polarity-driven geometrical cluster growth model of budding yeast
Authors: Reniel B. Cabral and May T. Lim
Publication title: International Journal Of Modern Physics. C, Computational Physics, Physical Computation 21(9):1169, 2010
Abstract:
We present a polarity-driven activator-inhibitor model of budding yeast in a two-dimensional medium wherein impeding metabolites secretion (or growth inhibitors) and growth directionality are determined by the local nutrient level. We found that colony size and morphological features varied with nutrient concentration. A branched-type morphology is associated with high impeding metabolite concentration together with a high fraction of distal budding, while opposite conditions (low impeding metabolite concentration, high fraction of proximal budding) promote Eden-type patterns. Increasing the anisotropy factor (or polarity) produced other spatial patterns akin to the electrical breakdown under varying electric field. Rapid changes in the colony morphology, which we conjecture to be equivalent to a transition from an inactive quiescent state to an active budding state, appeared when nutrients were limited.
Full text available upon request to the author
Article title: Modeling U-turn traffic flow
Authors: Jay Samuel L. Combinido and May T. Lim
Publication title: Physica A: Statistical Mechanics and its Applications 389(17): 3640-3647, 2010
Abstract:
Median U-turns are sometimes installed to improve the traffic flow at busy intersections by eliminating left turns. Using a microscopic traffic model, we confirmed the presence of transitions from free flow to congested flow with increasing car inflow density. In addition, our proposed rules inside a U-turn curve, which accounted for safety issues and an asymmetric lane changing behavior (outer-to-inner vs. inner-to-outer lane transitions), predicted the speed distribution of cars after the U-turn curve. We found that U-turn curves installed for improving traffic flow at busy intersections produced their desired effects only when there is minimal interaction between cars.
Full text available upon request to the author
Article title: Effect of variable fishing strategy on fisheries under changing effort and pressure: An agent-based model application
Authors: Reniel B. Cabral, Rollan C. Geronimo, May T. Lim, Porfirio M. Aliño
Publication title: Ecological Modelling 221(2): 362-369, 2010
Abstract:
An agent-based model was used to evaluate the response of a two-species fish community to fishing boat exploration strategies, namely: boats following high-yield boats (Cartesian); boats fishing at random sites (stochast-random); and boats fishing at least exploited sites (stochast-pressure). At low fishing pressure, the stochast-random mode yielded a high average catch per boat while sustaining fish biomass. At high fishing pressure, the Cartesian mode was more effective. For the Cartesian strategy, fish biomass exhibited four distinct behaviors with increasing number of boats. In the first phase, the fish biomass dropped with increasing number of boats due to a corresponding rise in biomass extraction. Rapid exploitation occurred in the second phase, when two or more boats occupied the same initial area, that led to the faster abandonment of those sites which then underwent biomass recovery. In the third phase, adding more boats resulted in a fluctuating stock biomass, where the combined effects of initial spatial distribution of boats and rapid localization led to either full stock recovery when boats were eventually confined to a single location due to spillovers, or stock extirpation when the entire area became fully occupied. Beyond the third phase, stock extirpation was assured. In order to break the pattern of localization (bandwagon effect), we introduced stochast-random intruders in a Cartesian-dominated fishery. Adding a single intruder changed the patchy-structured stock biomass pattern of a purely Cartesian fishery to a uniformly explored stock biomass pattern because of the additional spatial information provided by the intruder. Consequently, the average catch per boat increased but at the expense of a disproportionate decline in equilibrium biomass.
Full text available upon request to the author
Article title: Preferential detachment in broadcast signaling networks: Connectivity and cost trade-off
Authors: May Lim, Dan Braha, Sanith Wijesinghe, Stephenson Tucker, et al.
Publication title: EPL (Europhysics Letters) 79(5): 58005, 2007
Abstract:
We consider a network of nodes distributed in physical space without physical links communicating through message broadcasting over specified distances. Typically, communication using smaller distances is desirable due to savings in energy or other resources. We introduce a network formation mechanism to enable reducing the distances while retaining connectivity. Nodes, which initially transmit signals at a prespecified maximum distance, subject links to preferential detachment by autonomously decreasing their transmission radii while satisfying conditions of zero communication loss and fixed maximum node-hopping distance for signaling. Applied to networks with various spatial topologies, we find cost reductions as high as 90% over networks that are restricted to have all nodes with equal transmission distance.
Article title: Global pattern formation and ethnic/cultural violence
Authors: May Lim, Richard Metzler, Yaneer Bar-Yam
Publication title: Science 317(5844): 1540-1544, 2007
Abstract:
We identify a process of global pattern formation that causes regions to differentiate by culture. Violence arises at boundaries between regions that are not sufficiently well defined. We model cultural differentiation as a separation of groups whose members prefer similar neighbors, with a characteristic group size at which violence occurs. Application of this model to the area of the former Yugoslavia and to India accurately predicts the locations of reported conflict. This model also points to imposed mixing or boundary clarification as mechanisms for promoting peace.
Article title: Primary spherical aberration in two-color (two-photon) excitation fluorescence microscopy with two confocal excitation beams
Authors: May Lim and Caesar Saloma
Publication title: Applied optics 42(17): 3398-3406, 2003
Abstract:
We study the effects of primary spherical aberration on the three-dimensional point spread function (PSF) of the two-color (two-photon) excitation (2CE) (2PE) fluorescence microscope with two confocal excitation beams that are separated by an angle θ. The two excitation wavelengths λ1 and λ2 are related to the single-photon excitation wavelength λe by: 1/λe = 1/λ1 + 1/λ2. The general case is considered where both focused beams independently suffer from spherical aberration. For θ = 0, π/2, and π, the resulting deterioration of the PSF structure is evaluated for different values of the spherical aberration coefficients via the Linfoot’s criteria of fidelity, structural content, and correlation quality. The corresponding degradation of the peak 2CE fluorescence intensity is also determined. Our findings are compared with that of the 2PE fluorescence (λ1 = λ2) under the same aberration conditions. We found that the 2CE microscope is more robust against spherical aberration than its 2PE counterpart, with the π/2 configuration providing the clearest advantage. The prospect of aberration correction in the two-beam 2CE microscope is also discussed.
Full text available upon request to the author
Article title: Self-organized queuing and scale-free behavior in real escape panic
Authors: Caesar Saloma, Gay Jane Perez, Giovanni Tapang, May Lim, et al.
Publication title: Proceedings of the National Academy of Sciences 100(21): 11947-11952, 2003
Abstract:
Numerical investigations of escape panic of confined pedestrians have revealed interesting dynamical features such as pedestrian arch formation around an exit, disruptive interference, self-organized queuing, and scale-free behavior. However, these predictions have remained unverified because escape panic experiments with real systems are difficult to perform. For mice escaping out of a water pool, we found that for a critical sampling rate the escape behavior exhibits the predicted features even at short observation times. The mice escaped via an exit in bursts of different sizes that obey exponential and (truncated) power-law distributions depending on exit width. Oversampling or undersampling the mouse escape rate prevents the observation of the predicted features. Real systems are normally subject to unavoidable constraints arising from occupancy rate, pedestrian exhaustion, and nonrigidity of pedestrian bodies. The effect of these constraints on the dynamics of real escape panic is also studied.
Article title: Direction-sensitive subwavelength displacement measurements at diffraction-limited spatial resolution
Authors: Peter John Rodrigo, May Lim, Caesar Saloma
Publication title: Optics letters 27(1): 25-27, 2002
Abstract:
Direction-sensitive displacement measurements at diffraction-limited spatial resolution are demonstrated with an interferometric optical-feedback semiconductor laser confocal imaging system. Subwavelength axial movements of the reflecting sample, including the directions of motion, are detected within the depth of field. A comparison of theory and actual instrument performance is presented.
Full text available upon request to the author
Article title: Gravity-assisted segregation of granular materials of equal mass and size
Authors: Johnrob Bantang, May Lim, Christopher Monterola, Caesar Saloma
Publication title: Physical Review E 66(4): 041306, 2002
Abstract:
High-resolution segregation is demonstrated for elastic granular materials of the same mass and size. Each grain starts at a randomly selected position in the entrance facet of a cylinder, accelerates downwards due to gravity, and then bounces against a massive obstacle with a collision cross section that is proportional to the facet size. Bounce dynamics of the falling grain is a function of its relative elasticity with the obstacle. Subsequent collisions of the grain with the wall are assumed to be perfectly elastic. In the absence of interparticle collisions, grain focusing occurs at points along the cylinder axis. In the absence of rotation, focusing occurs regardless of the initial locations and (downward) velocities of the grains at the entrance facet. The focus location depends only on the coefficient of restitution of the falling particle and the obstacle size. Grains arrive at the focus in temporally localized bursts even if released simultaneously from the facet. Efficient segregation is, therefore, achieved without additional mechanical work (e.g., shaking, spinning) on the system configuration.
Full text available upon request to the author
Article title: Accurate forecasting of the undecided population in a public opinion poll
Authors: Christopher Monterola, May Lim, Jerrold Garcia, Caesar Saloma
Publication title: Journal of Forecasting 21(6): 435-449, 2002
Abstract:
The problem of pollsters is addressed which is to forecast accurately the final answers of the undecided respondents to the primary question in a public opinion poll. The task is viewed as a pattern-recognition problem of correlating the answers of the respondents to the peripheral questions in the survey with their primary answers. The underlying pattern is determined with a supervised artificial neural network that is trained using the peripheral answers of the decided respondents whose primary answers are also known. With peripheral answers as inputs, the trained network outputs the most probable primary response of an undecided respondent. For a poll conducted to determine the approval rating of the (former) Philippine president, J. E. Estrada in December 1999 and March 2000, the trained network predicted with a 95% success rate the direct responses of a test population that consists of 24.57% of the decided population who were excluded in the network training set. For the undecided population (22.67% of December respondents; 23.67% of March respondents), the network predicted a final response distribution that is consistent with the approval/disapproval ratio of the decided population.
Full text available upon request to the author
Article title: Confocality condition in two-color excitation microscopy with two focused excitation beams
Authors: May Lim and Caesar Saloma
Publication title: Optics communications 207(1): 121-130, 2002
Abstract:
We evaluate the point spread function (PSF) of the two-color excitation (2CE) microscope when the confocality condition is not strictly satisfied by the two focused excitation beams which are separated by an angle θ≠0. The 2CE wavelengths λ1 and λ2 are related to the single-photon excitation wavelength λe of the sample according to: 1/λe=1/λ1+1/λ2. Spatio-temporal simultaneity for the two excitation beams is essential in 2CE (λ1≠λ2). Only aberration-free misalignment of the geometrical foci is considered and the degradation of the peak 2CE fluorescence intensity (F2cp) is determined as a function of the focus separation for θ=0,π/2 and π. The deterioration of the fluorescence PSF is also evaluated using the Linfoot's criteria of fidelity, structural content and correlation quality. We compare the 2CE PSF behavior with that of the two-photon excitation (2PE) fluorescence (λ1=λ2) under the same misalignment settings. At θ=π/2, the F2cp degrades less rapidly than the peak 2PE fluorescence intensity (F2pp) for misalignments that are confined within the focal plane of the focusing lens L1 for λ1. At θ=π,F2cp and F2pp degrade in a similar manner. For misalignments along the optical axis of L1 and at θ=π/2, the F2cp degrades monotonically while the F2pp degradation is accompanied by fluctuations caused by two-beam interference. Our calculations reveal that 2CE imaging is more resilient to the ill-effects of misalignment than the two-beam 2PE.
Full text available upon request to the author
Article title: Streaming, disruptive interference and power-law behavior in the exit dynamics of confined pedestrians
Authors: Gay Jane Perez, Giovanni Tapang, May Lim, Caesar Saloma
Publication title: Physica A: Statistical Mechanics and its Applications 312(3): 609-618, 2002
Abstract:
We analyze the exit dynamics of pedestrians who are initially con(ned in a room. Pedestrians are modeled as cellular automata and compete to escape via a known exit at the soonest possible time. A pedestrian could move forward, backward, left or right within each iteration time dependingon adjacent cell vacancy and in accordance with simple rules that determine the compulsion to move and physical capability relative to his neighbors. The arching signatures of jammingwere observed and the pedestrians exited in bursts of various sizes. Power-law behavior is found in the burst-size frequency distribution for exit widths w greater than one cell dimension (w ¿ 1). The slope of the power-law curve varies with w from −1:3092 (w = 2) to −1:0720 (w = 20). Streamingwhich is a di8usive behavior, arises in large burst sizes and is more likely in a single-exit room with w = 1 and leads to a counterintuitive result wherein an average exit throughput Q is obtained that is higher than with w = 2; 3, or 4. For a two-exit room (w = 1), Q is not greater than twice the yield of a single-exit room. If the doors are not separated far enough (¡ 4w), Q becomes even signi(cantly less due to a collective slow-down that emerges amongpedestrians crossingin each other’s path (disruptive interference e8ect). For the same w and door number, Q is also higher with relaxed pedestrians than with anxious ones. c 2002 Elsevier Science B.V. All rights reserved.
Full text available upon request to the author
Article title: Noise-enhanced measurement of weak doublet spectra with a Fourier-transform spectrometer and a 1-bit analog-to-digital converter
Authors: May Lim and Caesar Saloma
Publication title: Applied Optics 40(11): 1767-1775, 2001
Abstract:
We demonstrate an efficient noise dithering procedure for measuring the power spectrum of a weak spectral doublet with a Fourier-transform spectrometer in which the subthreshold interferogram is measured by a 1-bit analog-to-digital converter without oversampling. In the absence of noise, no information is obtained regarding the doublet spectrum because the modulation term s(x) of its interferogram is below the instrumental detection limit B, i.e., |s(x)| < B, for all path difference x values. Extensive numerical experiments are carried out concerning the recovery of the doublet power spectrum that is represented by s(x) = (s(0)/2)exp(-pi(2)x(2)/beta)[cos(2pif(1)x) + cos(2pif(2)x)], where s(0) is a constant, beta is the linewidth factor, and ?f? = (f(1) + f(2))/2. Different values of ?f?, s(0), and beta are considered to evaluate thoroughly the accuracy of the procedure to determine the unknown values of f(1) and f(2), the spectral linewidth, and the peak values of the spectral profiles. Our experiments show that, even for short observation times, the resonant frequencies of s(x) could be located with high accuracy over a wide range of ?f? and beta values. Signal-to-noise ratios as high as 50 are also gained for the recovered power spectra. The performance of the procedure is also analyzed with respect to another method that recovers the amplitude values of s(x) directly.
Full text available upon request to the author
Article title: Enhancement of low-resolution Raman spectra by simplex projection
Authors: May Lim and Caesar Saloma
Publication title: Optics communications 186(4-6): 237-243, 2000
Abstract:
We demonstrate the enhancement of low-resolution spontaneous Raman spectra by simplex projection which extrapolates the high-frequency components that are lost when the entrance slit width w of the grating spectrometer is widened to increase the optical throughput. The improvement in the signal-to-noise ratio of the measured Raman spectrum is accompanied by an unwanted but inevitable decrease in the resolving power of the spectrometer. Spectral extrapolation by simplex projection [Opt. Commun. 176 (2000) 373] is applied to the linearly deconvolved low-frequency Fourier transform of the measured Raman spectrum, to recover accurately and rapidly the information (peak locations and profiles) that are lost. The weak Raman spectrum of CCl4 is utilized as the test signal. In terms of the Linfoot’s criteria, the combination of simplex projection and linear deconvolution succeeded in enhancing a low-resolution Raman spectrum (w=150μm) to obtain information that are available in raw spectra measured at w=75μm. The recovery performance is superior to what could be achieved via linear deconvolution alone.
Full text available upon request to the author
Article title: Spectral extrapolation by simplex projection
Authors: May Lim, Gemma Narisma, Caesar Saloma
Publication title: Optics Communications 176(4-6): 373-385, 2000
Abstract:
Rapid and accurate recovery of the lost high-frequency components in the undersampled representation of a bandlimited signal s(x) is demonstrated using the simplex projection method (SPM). The spectral extrapolation technique is effective if: 1) Fourier spectrum S(f) of s(x) contains features that are exhibited regularly within the signal bandwidth, and 2) Fourier transform {S(m)} of the undersampled representation of s(x) contains sufficient information about the said regularities. The SPM is utilized to determine the various features contained in {S(m)} and to establish their possible pattern of appearance. The performance of the recovery procedure is tested as a function of the sampling rate. Two test signals with distinctly different Fourier spectrum profiles are considered: 1) Interferogram of a spectral doublet, and 2) Four-point object. In both cases, the bandwidth of s(x) is known a priori and used to determine the number of unknowns to be solved. For an undersampled interferogram that contains only 54% of the energy of the spectral doublet, 42 unknown components have been calculated to decrease the normalized mean-square error of the interpolated signal by 75% relative to the undersampled data. The extrapolation technique is shown to be robust to the presence of additive noise in S(f).
Full text available upon request to the author
Article title: Direct signal recovery from threshold crossings
Authors: May Lim and Caesar Saloma
Publication title: Physical Review E 58(5): 6759, 1998
Abstract:
We present a method for directly obtaining the 2 M equally sampled amplitude values of the analog input signal s (t) from the 2 M locations {t i} where it intersects with a reference signal r (t)= A cos (2 π f r t). Until now, high-accuracy signal recovery in sinusoid-crossing sampling had been achieved only indirectly using spectral methods. The recovery requirements are (1)| s (t)|< A and (2) W<~ 2 f r where W is the bandwidth of s (t). The recovery method is evaluated as a function of the accuracy in which the crossings are located, and the sampling period T= 2 M Δ, where Δ= 1/2 f r. Its performance is also compared with other direct interpolation schemes.
Full text available upon request to the author