Journal articles on the topic 'Temporal metrics'
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Foote, Mike. "Temporal variation in extinction risk and temporal scaling of extinction metrics." Paleobiology 20, no. 4 (1994): 424–44. http://dx.doi.org/10.1017/s0094837300012914.
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Many areas of paleobiological research require reliable extinction metrics. Branching-and-extinction simulations and data on Phanerozoic marine families and genera are used to investigate the relationship between interval length and commonly used extinction metrics. Normalization of extinction metrics for interval length is problematic, even when interval length is known without error, because normalization implicitly assumes some model of variation in extinction risk within an interval. If extinction risk within an interval were constant, or if it varied but played no role in the definition of stratigraphic intervals, then Van Valen's time-normalized extinction metric would provide a measure of average extinction risk that is effectively unbiased by interval length. When extinction risk varies greatly within an interval and interval boundaries are drawn at times of heavy extinction, extinction metrics that normalize for interval length are negatively correlated with interval length. Despite its intuitive appeal, the per-taxon extinction rate (proportional extinction per million years) is biased by interval length under a wide range of extinction models.Empirically, time-normalized extinction metrics for Phanerozoic families and genera are negatively correlated with interval length. This is consistent with an extinction model in which many times of very low risk are punctuated by a few times of very high risk which in turn determine stage boundaries. Origination and extinction patterns are similar, but origination intensity varies less among stages than extinction intensity. This observation has at least two plausible explanations: that origination episodes are more protracted than extinction episodes, and that biologic groups do not respond in unison to origination opportunities the way they seem to respond during extinction events. For families and genera, there is enough variation in extinction intensity among stages that stage length can be ignored when studying certain extinction patterns over the entire Phanerozoic.
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Knight, Rachael-Anne. "Assessing the temporal reliability of rhythm metrics." Journal of the International Phonetic Association 41, no. 3 (November 11, 2011): 271–81. http://dx.doi.org/10.1017/s0025100311000326.
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Despite the current popularity of rhythm metrics, there has been relatively little work aimed at establishing their validity or reliability, important characteristics of any empirical measure. The current paper focuses on the stability, or temporal reliability, of rhythm metrics by establishing if they give consistent results for the same speakers, in the same task, on successive occasions. Four speakers of Southern British English were recorded reading ‘The North Wind and the Sun’ (NWS) passage on three consecutive days. Results indicated that some measures correlate more highly across time than others, and the choice of a measure that is both reliable and valid is discussed. It is suggested that the metric that best fits these criteria is formulated in terms of the proportion of vowels within an utterance (%V).
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Warren, Joshua L., Montserrat Fuentes, Amy H. Herring, and Peter H. Langlois. "Air Pollution Metric Analysis While Determining Susceptible Periods of Pregnancy for Low Birth Weight." ISRN Obstetrics and Gynecology 2013 (January 30, 2013): 1–9. http://dx.doi.org/10.1155/2013/387452.
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Multiple metrics to characterize air pollution are available for use in environmental health analyses in addition to the standard Air Quality System (AQS) pollution monitoring data. These metrics have complete spatial-temporal coverage across a domain and are therefore crucial in calculating pollution exposures in geographic areas where AQS monitors are not present. We investigate the impact that two of these metrics, output from a deterministic chemistry model (CMAQ) and from a spatial-temporal downscaler statistical model which combines information from AQS and CMAQ (DS), have on risk assessment. Using each metric, we analyze ambient ozone's effect on low birth weight utilizing a Bayesian temporal probit regression model. Weekly windows of susceptibility are identified and analyzed jointly for all births in a subdomain of Texas, 2001–2004, and results from the different pollution metrics are compared. Increased exposures during weeks 20–23 of the pregnancy are identified as being associated with low birth weight by the DS metric. Use of the CMAQ output alone results in increased variability of the final risk assessment estimates, while calibrating the CMAQ through use of the DS metric provides results more closely resembling those of the AQS. The AQS data are still preferred when available.
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Ibadah, Nisrine, Khalid Minaoui, Mohammed Rziza, Mohammed Oumsis, and César Benavente-Peces. "Deep Validation of Spatial Temporal Features of Synthetic Mobility Models." Computers 7, no. 4 (December 16, 2018): 71. http://dx.doi.org/10.3390/computers7040071.
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This paper analyzes the most relevant spatial-temporal stochastic properties of benchmark synthetic mobility models. Each pattern suffers from various mobility flaws, as will be shown by the models’ validation. A set of metrics is used to describe mobility features, such as the speed decay problem, the density wave phenomenon, the spatial node distribution, and the average neighbor percentage. These metrics have already been validated for the random waypoint mobility model (RWPMM), but they have not yet been verified for other mobility patterns that are most frequently used. For this reason, this investigation attempts to deeply validate those metrics for other mobility models, namely the Manhattan Grid mobility, the Reference Point Group mobility, the Nomadic Community mobility, the Self-Similar Least Action Walk, and SMOOTH models. Moreover, we propose a novel mobility metric named the “node neighbors range”. The relevance of this new metric is that it proves at once the set of outcomes of previous metrics. It offers a global view of the overall range of mobile neighbors during the experimental time. The current research aims to more rigorously understand mobility features in order to conduct a precise assessment of each mobility flaw, given that this fact further impacts the performance of the whole network. These validations aim to summarize several parameters into 18,126 different scenarios with an average of 486 validated files. An exhaustive analysis with details like those found in this paper leads to a good understanding of the accurate behaviors of mobility models by displaying the ability of every pattern to deal with certain topology changes, as well as to ensure network performances. Validation results confirm the effectiveness and robustness of our novel metric.
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Victor, J. D., and K. P. Purpura. "Nature and precision of temporal coding in visual cortex: a metric-space analysis." Journal of Neurophysiology 76, no. 2 (August 1, 1996): 1310–26. http://dx.doi.org/10.1152/jn.1996.76.2.1310.
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1. We recorded single-unit and multi-unit activity in response to transient presentation of texture and grating patterns at 25 sites within the parafoveal representation of V1, V2, and V3 of two awake monkeys trained to perform a fixation task. In grating experiments, stimuli varied in orientation, spatial frequency, or both. In texture experiments, stimuli varied in contrast, check size, texture type, or pairs of these attributes. 2. To examine the nature and precision of temporal coding, we compared individual responses elicited by each set of stimuli in terms of two families of metrics. One family of metrics, D(spike), was sensitive to the absolute spike time (following stimulus onset). The second family of metrics, D(interval), was sensitive to the pattern of interspike intervals. In each family, the metrics depend on a parameter q, which expresses the precision of temporal coding. For q = 0, both metrics collapse into the "spike count" metric D(Count), which is sensitive to the number of impulses but insensitive to their position in time. 3. Each of these metrics, with values of q ranging from 0 to 512/s, was used to calculate the distance between all pairs of spike trains within each dataset. The extent of stimulus-specific clustering manifest in these pairwise distances was quantified by an information measure. Chance clustering was estimated by applying the same procedure to synthetic data sets in which responses were assigned randomly to the input stimuli. 4. Of the 352 data sets, 170 showed evidence of tuning via the spike count (q = 0) metric, 294 showed evidence of tuning via the spike time metric, 272 showed evidence of tuning via the spike interval metric to the stimulus attribute (contrast, check size, orientation, spatial frequency, or texture type) under study. Across the entire dataset, the information not attributable to chance clustering averaged 0.042 bits for the spike count metric, 0.171 bits for the optimal spike time metric, and 0.107 bits for the optimal spike interval metric. 5. The reciprocal of the optimal cost q serves as a measure of the temporal precision of temporal coding. In V1 and V2, with both metrics, temporal precision was highest for contrast (ca. 10-30 ms) and lowest for texture type (ca. 100 ms). This systematic dependence of q on stimulus attribute provides a possible mechanism for the simultaneous representation of multiple stimulus attributes in one spike train. 6. Our findings are inconsistent with Poisson models of spike trains. Synthetic data sets in which firing rate was governed by a time-dependent Poisson process matched to the observed poststimulus time histogram (PSTH) overestimated clustering induced by D(count) and, for low values of q, D(spike)[q] and D(intervals)[q]. Synthetic data sets constructed from a modified Poisson process, which preserved not only the PSTH but also spike count statistics accounted for the clustering induced by D(count) but underestimated the clustering induced by D(spike)[q] and D(interval)[q].
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George, Scott D., Daniel S. Stich, and Barry P. Baldigo. "Considerations of variability and power for long-term monitoring of stream fish assemblages." Canadian Journal of Fisheries and Aquatic Sciences 78, no. 3 (March 2021): 301–11. http://dx.doi.org/10.1139/cjfas-2020-0013.
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Little attention has been given to optimizing statistical power for monitoring stream fish assemblages. We explored the relationship between temporal variability and statistical power using 34 metrics from fish community data collected annually at six sites over 10 years via electrofishing. Metric variability differed by the life stage and group of species considered, use of abundance or mass data, and data standardization technique. Lower variability was associated with community data, abundance data, and time-based standardizations, while greater variability was associated with young-of-the-year data, mass data, and area-based standardizations. Simulation-based power analysis indicated metric choice, and to a lesser degree, monitoring design (annual, biennial, endpoints, or haphazard sampling) influenced power to detect change. Across a fixed number of surveys (N = 60), endpoints sampling performed best. The N needed to detect change was heavily dependent upon metric choice for all monitoring designs, with the most biologically specific metrics requiring greater N. Large savings in effort and resource expenditure can be obtained utilizing biologically relevant metrics that are robust to temporal noise within an appropriate sampling design.
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Stoller, Scott D., and Thang Bui. "Mining hierarchical temporal roles with multiple metrics." Journal of Computer Security 26, no. 1 (November 30, 2017): 121–42. http://dx.doi.org/10.3233/jcs-17989.
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Chockler, Hana, Orna Kupferman, and Moshe Y. Vardi. "Coverage metrics for temporal logic model checking*." Formal Methods in System Design 28, no. 3 (May 2006): 189–212. http://dx.doi.org/10.1007/s10703-006-0001-6.
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Ellenbogen, Michael I., Laura Prichett, Pamela T. Johnson, and Daniel J. Brotman. "Development of a Simple Index to Measure Overuse of Diagnostic Testing at the Hospital Level Using Administrative Data." Journal of Hospital Medicine 16, no. 2 (February 1, 2021): 77–83. http://dx.doi.org/10.12788/jhm.3547.
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OBJECTIVE: We developed a diagnostic overuse index that identifies hospitals with high levels of diagnostic intensity by comparing negative diagnostic testing rates for common diagnoses. METHODS: We prospectively identified candidate overuse metrics, each defined by the percentage of patients with a particular diagnosis who underwent a potentially unnecessary diagnostic test. We used data from seven states participating in the State Inpatient Databases. Candidate metrics were tested for temporal stability and internal consistency. Using mixed-effects ordinal regression and adjusting for regional and hospital characteristics, we compared results of our index with three Dartmouth health service area-level utilization metrics and three Medicare county-level cost metrics. RESULTS: The index was comprised of five metrics with good temporal stability and internal consistency. It correlated with five of the six prespecified overuse measures. Among the Dartmouth metrics, our index correlated most closely with physician reimbursement, with an odds ratio of 2.02 (95% CI, 1.11-3.66) of being in a higher tertile of the overuse index when comparing tertiles 3 and 1 of this Dartmouth metric. Among the Medicare county-level metrics, our index correlated most closely with standardized costs of procedures per capita, with an odds ratio of 2.03 (95% CI, 1.21-3.39) of being in a higher overuse index tertile when comparing tertiles 3 and 1 of this metric. CONCLUSIONS: We developed a novel overuse index that is preliminary in nature. This index is derived from readily available administrative data and shows some promise for measuring overuse of diagnostic testing at the hospital level.
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Yang, Chun Ting, Yang Liu, and Jing Yu. "Research on Video Sequences Quality Based on Motion Intensity." Applied Mechanics and Materials 20-23 (January 2010): 1476–81. http://dx.doi.org/10.4028/www.scientific.net/amm.20-23.1476.
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Perception video sequences quality metrics are of great potential benefit to the video industry, as they promise the means to evaluate the performance of acquisition, display, coding and communication systems. Many researchers have focused on developing digital video sequences quality metrics which produce results that accurately emulate subjective responses. However, to be widely applicable a metric must also work over a wide range of quality, and be useful for in-service quality monitoring. We have developed novel video distortion metrics for video sequences. The temporal correlations of video frames and the visual interest feature are considered in this method. Meanwhile the metrics are capable of capturing spatial distortions in video sequences. The metrics correlate well with subjective video transmission quality measures because perception distortions of human were took account of. Results are presented that demonstrate our perceptual quality metric performs better than existing methods.
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Gilinsky, Norman L., and Richard K. Bambach. "Asymmetrical patterns of origination and extinction in higher taxa." Paleobiology 13, no. 4 (1987): 427–45. http://dx.doi.org/10.1017/s0094837300009027.
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Using Sepkoski's compendium of fossil marine families (1982a, and updates), we have analyzed the changing pace of familial origination and extinction within 55 extinct and 44 extant higher taxa of marine organisms. Eight different metrics were calculated, and least-squares regression analysis was used to identify within-taxon trends in the data. All metrics and analyses gave essentially the same results. Origination metrics decline significantly with time during the histories of higher taxa, while extinction metrics increase significantly. The number of statistically significant declines of origination metric, however, substantially and invariably exceeds the number of statistically significant increases of extinction metric for each pair of corresponding metrics analyzed. It follows, therefore, that temporal trends in the pace of origination and extinction within higher taxa are highly asymmetrical.Further analysis shows that truncating data from temporal endpoints has little effect upon the intensity of origination trends, implying that declining pace of origination is a sustained property of the long term histories of taxa. Such truncation, however, reduces the intensity of extinction trends to statistical insignificance and confirms Van Valen's (1985a) suggestion that extinction behaves largely as a stationary process. If the histories of higher taxa are characterized by substantial declines in the pace of origination while the pace of extinction remains largely stationary, it follows that declining pace of origination is an important controlling factor in long term taxic evolution.
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Brasselet, Romain, Roland S. Johansson, and Angelo Arleo. "Quantifying Neurotransmission Reliability Through Metrics-Based Information Analysis." Neural Computation 23, no. 4 (April 2011): 852–81. http://dx.doi.org/10.1162/neco_a_00099.
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We set forth an information-theoretical measure to quantify neurotransmission reliability while taking into full account the metrical properties of the spike train space. This parametric information analysis relies on similarity measures induced by the metrical relations between neural responses as spikes flow in. Thus, in order to assess the entropy, the conditional entropy, and the overall information transfer, this method does not require any a priori decoding algorithm to partition the space into equivalence classes. It therefore allows the optimal parameters of a class of distances to be determined with respect to information transmission. To validate the proposed information-theoretical approach, we study precise temporal decoding of human somatosensory signals recorded using microneurography experiments. For this analysis, we employ a similarity measure based on the Victor-Purpura spike train metrics. We show that with appropriate parameters of this distance, the relative spike times of the mechanoreceptors’ responses convey enough information to perform optimal discrimination—defined as maximum metrical information and zero conditional entropy—of 81 distinct stimuli within 40 ms of the first afferent spike. The proposed information-theoretical measure proves to be a suitable generalization of Shannon mutual information in order to consider the metrics of temporal codes explicitly. It allows neurotransmission reliability to be assessed in the presence of large spike train spaces (e.g., neural population codes) with high temporal precision.
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Keizer-Vlek, Hanneke E., Piet F. M. Verdonschot, Ralf C. M. Verdonschot, and Paul W. Goedhart. "Quantifying spatial and temporal variability of macroinvertebrate metrics." Ecological Indicators 23 (December 2012): 384–93. http://dx.doi.org/10.1016/j.ecolind.2012.04.025.
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Costa, André H. M., Helard Becerra Martinez, Daniel G. Silva, and Mylène C. Q. Farias. "Analyzing the effect of adding temporal features to an autoencoder-based video quality model." Electronic Imaging 2021, no. 9 (January 18, 2021): 261–1. http://dx.doi.org/10.2352/issn.2470-1173.2021.9.iqsp-261.
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According to Cisco, most Internet traffic is currently comprised of videos. Therefore, developing a quality assessment method for assuring that those videos are received and displayed with quality at the user side is an important and challenging task. As a consequence, over the last decades, several no-reference video quality metrics have been proposed with the goal of blindly predicting (with no access to the original signal) the quality of videos in streaming applications. One of such metrics is NAVE, whose architecture includes an auto-encoder module that produces a compact set of visual features with a higher descriptive capacity. Nevertheless, the visual features in NAVE do not include descriptive temporal features that are sensitive to temporal degradation. In this work, we analyze the effect on accuracy performance of using a new type of temporal features, based on natural scene statistics. This approach has the goal of making the tested video quality metric more generic, i.e. sensitive to both spatial and temporal distortions and therefore adequate for video streaming applications.
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Hunt, Gene. "Measuring rates of phenotypic evolution and the inseparability of tempo and mode." Paleobiology 38, no. 3 (2012): 351–73. http://dx.doi.org/10.1666/11047.1.
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Rates of phenotypic evolution are central to many issues in paleontology, but traditional rate metrics such as darwins or haldanes are seldom used because of their strong dependence on interval length. In this paper, I argue that rates are usefully thought of as model parameters that relate magnitudes of evolutionary divergence to elapsed time. Starting with models of directional evolution, random walks, and stasis, I derive for each a reasonable rate metric. These metrics can be linked to existing approaches in evolutionary biology, and simulations show that they can be estimated accurately at any temporal resolution via maximum likelihood, but only when that metric's underlying model is true.The estimation of generational rates of a random walk under realistic paleontological conditions is compared with simulations to that of a prominent alternative approach, Gingerich's LRI (log-rate, log-interval) method. Generational rates are estimated poorly by LRI; they often reflect sampling error more than the actual pace of change. Further simulations show that under some realistic conditions, it is simply not possible to infer generational rates from coarsely sampled populations.These modeling results indicate a complex dependence between evolutionary mode and the measurement of evolutionary rates, and that there is unlikely to be a rate metric that works well for all traits and time scales. Compilations of paleontological and phylogenetic data indicate that all of the three rate metrics derived here show some relationship with interval length. Although there is no perfect rate metric, at present the most practical choices derive from the parameters of the stasis and random walk models. The latter, called the step variance, is particularly promising as a rate metric in paleontology and comparative biology.
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Kovács, György, Gheorghe Sebestyen, and Anca Hangan. "Evaluation metrics for anomaly detection algorithms in time-series." Acta Universitatis Sapientiae, Informatica 11, no. 2 (December 1, 2019): 113–30. http://dx.doi.org/10.2478/ausi-2019-0008.
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Abstract Time-series are ordered sequences of discrete-time data. Due to their temporal dimension, anomaly detection techniques used in time-series have to take into consideration time correlations and other time-related particularities. Generally, in order to evaluate the quality of an anomaly detection technique, the confusion matrix and its derived metrics such as precision and recall are used. These metrics, however, do not take this temporal dimension into consideration. In this paper, we propose three metrics that can be used to evaluate the quality of a classification, while accounting for the temporal dimension found in time-series data.
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Basharat, Aysha, Jeannette R. Mahoney, and Michael Barnett-Cowan. "Temporal Metrics of Multisensory Processing Change in the Elderly." Multisensory Research 32, no. 8 (December 11, 2019): 715–44. http://dx.doi.org/10.1163/22134808-20191458.
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Abstract Older adults exhibit greater multisensory response time (RT) facilitation by violating the race model more than young adults; this is commonly interpreted as an enhancement in perception. Older adults typically exhibit wider temporal binding windows (TBWs) and points of subjective simultaneity (PSS) that typically lie farther from true simultaneity as compared to young adults when simultaneity judgment (SJ) and temporal-order judgment (TOJ) tasks are utilized; this is commonly interpreted as an impairment in perception. Here we explore the relation between the three tasks in order to better assess audiovisual multisensory temporal processing in both young and older adults. Our results confirm previous reports showing that audiovisual RT, TBWs and PSSs change with age; however, we show for the first time a significant positive relation between the magnitude of race model violation in young adults as a function of the PSS obtained from the audiovisual TOJ task (r: 0.49, p: 0.007), that is absent in older adults (r: 0.13, p: 0.58). Furthermore, we find no evidence for the relation between race model violation as a function of the PSS obtained from the audiovisual SJ task in both young (r: −0.01, p: 0.94) and older adults (r: 0.1, p: 0.66). Our results confirm previous reports that (i) audiovisual temporal processing changes with age; (ii) distinct processes are likely involved in simultaneity and temporal-order perception; and (iii) common processing between race model violation and temporal-order judgment is impaired in the elderly.
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Park, J., J. Obeysekera, and J. Barnes. "Temporal energy partitions of Florida extreme sea level events as a function of Atlantic multidecadal oscillation." Ocean Science 6, no. 2 (June 15, 2010): 587–93. http://dx.doi.org/10.5194/os-6-587-2010.
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Abstract. An energy-conservative metric based on the discrete wavelet transform is applied to assess the relative energy distribution of extreme sea level events across different temporal scales. The metric is applied to coastal events at Key West and Pensacola Florida as a function of two Atlantic Multidecadal Oscillation (AMO) regimes. Under AMO warm conditions there is a small but significant redistribution of event energy from nearly static into more dynamic (shorter duration) timescales at Key West, while at Pensacola the AMO-dependent changes in temporal event behaviour are less pronounced. Extreme events with increased temporal dynamics might be consistent with an increase in total energy of event forcings which may be a reflection of more energetic storm events during AMO warm phases. As dynamical models mature to the point of providing regional climate index predictability, coastal planners may be able to consider such temporal change metrics in planning scenarios.
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Park, J., J. Obeysekera, and J. Barnes. "Temporal energy partitions of Florida extreme sea level events as a function of Atlantic multidecadal oscillation." Ocean Science Discussions 7, no. 2 (March 11, 2010): 501–19. http://dx.doi.org/10.5194/osd-7-501-2010.
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Abstract. An energy-conservative metric based on the discrete wavelet transform is applied to assess the relative energy distribution of non-stationary extreme sea level events across different temporal scales. The metric is applied to coastal events at Key West and Pensacola Florida as a function of two Atlantic Multidecadal Oscillation (AMO) regimes. Under AMO warm conditions there is a small but significant redistribution of event energy from nearly static into more dynamic timescales at Key West, while at Pensacola the AMO-dependent changes in temporal event behaviour are less pronounced. Extreme events with increased temporal dynamics are consistent with an increase in total energy of event forcings which may be a reflection of more energetic storm events during AMO warm phases. As dynamical models mature to the point of providing regional climate index predictability, coastal planners may be able to consider such temporal change metrics in planning scenarios.
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Vorobjev, Ivan, and Natasha S. Barteneva. "Temporal Heterogeneity Metrics in Apoptosis Induced by Anticancer Drugs." Journal of Histochemistry & Cytochemistry 63, no. 7 (April 2, 2015): 494–510. http://dx.doi.org/10.1369/0022155415583534.
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Marinovic, Welber, and Derek H. Arnold. "Separable temporal metrics for time perception and anticipatory actions." Proceedings of the Royal Society B: Biological Sciences 279, no. 1730 (September 7, 2011): 854–59. http://dx.doi.org/10.1098/rspb.2011.1598.
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Reliable estimates of time are essential for initiating interceptive actions at the right moment. However, our sense of time is surprisingly fallible. For instance, time perception can be distorted by prolonged exposure (adaptation) to movement. Here, we make use of this to determine if time perception and anticipatory actions rely on the same or on different temporal metrics. Consistent with previous reports, we find that the apparent duration of movement is mitigated by adaptation to more rapid motion, but is unchanged by adaptation to slower movement. By contrast, we find symmetrical effects of motion-adaptation on the timing of anticipatory interceptive actions, which are paralleled by changes in perceived speed for the adapted direction of motion. Our data thus reveal that anticipatory actions and perceived duration rely on different temporal metrics.
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Reynolds, Stephanie, Therese Abrahamsson, Per Jesper Sjöström, Simon R. Schultz, and Pier Luigi Dragotti. "CosMIC: A Consistent Metric for Spike Inference from Calcium Imaging." Neural Computation 30, no. 10 (October 2018): 2726–56. http://dx.doi.org/10.1162/neco_a_01114.
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In recent years, the development of algorithms to detect neuronal spiking activity from two-photon calcium imaging data has received much attention, yet few researchers have examined the metrics used to assess the similarity of detected spike trains with the ground truth. We highlight the limitations of the two most commonly used metrics, the spike train correlation and success rate, and propose an alternative, which we refer to as CosMIC. Rather than operating on the true and estimated spike trains directly, the proposed metric assesses the similarity of the pulse trains obtained from convolution of the spike trains with a smoothing pulse. The pulse width, which is derived from the statistics of the imaging data, reflects the temporal tolerance of the metric. The final metric score is the size of the commonalities of the pulse trains as a fraction of their average size. Viewed through the lens of set theory, CosMIC resembles a continuous Sørensen-Dice coefficient—an index commonly used to assess the similarity of discrete, presence/absence data. We demonstrate the ability of the proposed metric to discriminate the precision and recall of spike train estimates. Unlike the spike train correlation, which appears to reward overestimation, the proposed metric score is maximized when the correct number of spikes have been detected. Furthermore, we show that CosMIC is more sensitive to the temporal precision of estimates than the success rate.
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YANG, J. X., D. M. TAN, and H. R. WU. "AN IMPAIRMENT METRIC FOR VIDEO TEMPORAL FLUCTUATION MEASURE." International Journal of Image and Graphics 11, no. 02 (April 2011): 251–64. http://dx.doi.org/10.1142/s0219467811004081.
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Temporal fluctuations are often observed in digitally compressed videos. However, it is difficult to accurately measure these fluctuation intensities with the traditional peak signal-to-noise ratio (PSNR) since the PSNR only provides a generic quality measure. Although specialized metrics have been proposed for temporal fluctuation measurement, e.g., the sum of squared differences (SSD) and the motion compensated SSD (MCSSD), these first difference based algorithms may falsely treat smooth continuous change of pixel values as temporal fluctuations. To overcome this problem, a motion estimated mean scaled absolute second difference (MEMSASD) is proposed here. The performance of the MEMSASD is examined using a number of video sequences with varying degrees of temporal fluctuations, generated by an H.264/AVC compliant codec using standard test video sequences. Compared with the PSNR and the SSD, the behavior of the MCSSD and the proposed metric provide better reflections of temporal fluctuation intensities as perceived by the human visual system (HVS), in terms of the Pearson correlation coefficient. The MEMSASD metric has an advantage over MCSSD in that it avoids misclassification of temporal fluctuations of pixels with smooth continuous change along the temporal axis.
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Bazzi, Hassan, Nicolas Baghdadi, Mohammad El Hajj, Mehrez Zribi, Dinh Ho Tong Minh, Emile Ndikumana, Dominique Courault, and Hatem Belhouchette. "Mapping Paddy Rice Using Sentinel-1 SAR Time Series in Camargue, France." Remote Sensing 11, no. 7 (April 11, 2019): 887. http://dx.doi.org/10.3390/rs11070887.
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This study proposes an effective method to map rice crops using the Sentinel-1 SAR (Synthetic Aperture Radar) time series over the Camargue region, Southern France. First, the temporal behavior of the SAR backscattering coefficient over 832 plots containing different crop types was analyzed. Through this analysis, the rice cultivation was identified using metrics derived from the Gaussian profile of the VV/VH time series (3 metrics), the variance of the VV/VH time series (one metric), and the slope of the linear regression of the VH time series (one metric). Using the derived metrics, rice plots were mapped through two different approaches: decision tree and Random Forest (RF). To validate the accuracy of each approach, the classified rice map was compared to the available national data. Similar high overall accuracy was obtained using both approaches. The overall accuracy obtained using a simple decision tree reached 96.3%, whereas an overall accuracy of 96.6% was obtained using the RF classifier. The approach, therefore, provides a simple yet precise and powerful tool to map paddy rice areas.
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Rodríguez-Pupo, Luis, Carlos Granell, and Sven Casteleyn. "An Analytics Platform for Integrating and Computing Spatio-Temporal Metrics." ISPRS International Journal of Geo-Information 8, no. 2 (January 26, 2019): 54. http://dx.doi.org/10.3390/ijgi8020054.
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In large-scale context-aware applications, a central design concern is capturing, managing and acting upon location and context data. The ability to understand the collected data and define meaningful contextual events, based on one or more incoming (contextual) data streams, both for a single and multiple users, is hereby critical for applications to exhibit location- and context-aware behaviour. In this article, we describe a context-aware, data-intensive metrics platform —focusing primarily on its geospatial support—that allows exactly this: to define and execute metrics, which capture meaningful spatio-temporal and contextual events relevant for the application realm. The platform (1) supports metrics definition and execution; (2) provides facilities for real-time, in-application actions upon metrics execution results; (3) allows post-hoc analysis and visualisation of collected data and results. It hereby offers contextual and geospatial data management and analytics as a service, and allow context-aware application developers to focus on their core application logic. We explain the core platform and its ecosystem of supporting applications and tools, elaborate the most important conceptual features, and discuss implementation realised through a distributed, micro-service based cloud architecture. Finally, we highlight possible application fields, and present a real-world case study in the realm of psychological health.
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Favorov, Oleg V., Eric Francisco, Jameson Holden, Olcay Kursun, Laila Zai, and Mark Tommerdahl. "Quantification of Mild Traumatic Brain Injury via Cortical Metrics: Analytical Methods." Military Medicine 184, Supplement_1 (March 1, 2019): 228–36. http://dx.doi.org/10.1093/milmed/usy411.
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Abstract Mild traumatic brain injuries are difficult to diagnose or assess with commonly used diagnostic methods. However, the functional state of cerebral cortical networks can be rapidly and effectively probed by measuring tactile-based sensory percepts (called cortical metrics), which are designed to exercise various components of cortical machinery. In this study, such cortical metrics were obtained from 52 college students before and after they experienced sports-related concussions by delivering vibrotactile stimuli to the index and middle fingertips. Performance on four of the sensory test protocols is described: reaction time, amplitude discrimination, temporal order judgment, and duration discrimination. The collected test performance data were analyzed using methods of uni- and multivariate statistics, receiver operated characteristic (ROC) curves, and discriminant analysis. While individual cortical metrics vary extensively in their ability to discriminate between control and concussed subjects, their combined discriminative performance greatly exceeds that of any individual metric, achieving cross-validated 93.0% sensitivity, 92.3% specificity, 93.0% positive predictive value, and 92.3% negative predictive value. The cortical metrics vector can be used to track an individual’s recovery from concussion. The study thus establishes that cortical metrics can be used effectively as a quantitative indicator of central nervous system health status.
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Fernandes, Rui, and M. T. Andrade. "Multimedia Content Classification Metrics for Content Adaptation." U.Porto Journal of Engineering 2, no. 2 (March 20, 2018): 14–25. http://dx.doi.org/10.24840/2183-6493_002.002_0003.
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Multimedia content consumption is very popular nowadays. However, not every content can be consumed in its original format: the combination of content, transport and access networks, consumption device and usage environment characteristics may all pose restrictions to that purpose. One way to provide the best possible quality to the user is to adapt the content according to these restrictions as well as user preferences. This adaptation stage can be best executed if knowledge about the content is known a-priori. In order to provide this knowledge we classify the content based on metrics to define its temporal and spatial complexity. The temporal complexity classification is based on the Motion Vectors of the predictive encoded frames and on the difference between frames. The spatial complexity classification is based on different implementations of an edge detection algorithm and an image activity measure.
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BACCI, GIORGIO, GIOVANNI BACCI, KIM G. LARSEN, and RADU MARDARE. "Converging from branching to linear metrics on Markov chains." Mathematical Structures in Computer Science 29, no. 1 (July 25, 2017): 3–37. http://dx.doi.org/10.1017/s0960129517000160.
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We study two well-known linear-time metrics on Markov chains (MCs), namely, the strong and strutter trace distances. Our interest in these metrics is motivated by their relation to the probabilistic linear temporal logic (LTL)-model checking problem: we prove that they correspond to the maximal differences in the probability of satisfying the same LTL and LTL−X(LTL without next operator) formulas, respectively.The threshold problem for these distances (whether their value exceeds a given threshold) is NP-hard and not known to be decidable. Nevertheless, we provide an approximation schema where each lower and upper approximant is computable in polynomial time in the size of the MC.The upper approximants are bisimilarity-like pseudometrics (hence, branching-time distances) that converge point-wise to the linear-time metrics. This convergence is interesting in itself, because it reveals a non-trivial relation between branching and linear-time metric-based semantics that does not hold in equivalence-based semantics.
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Liem, Alyssa T., and James G. McDaniel. "Improvement of acoustic and vibration models by temporal error metrics." Journal of the Acoustical Society of America 141, no. 5 (May 2017): 3834. http://dx.doi.org/10.1121/1.4988521.
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Fernandes, Bianca, and Ligia Batista. "Spatial-Temporal Analysis of the Forest Fragments Surrounding a Conservation Unit in the Southern Region of Brazil." Environmental Sciences Proceedings 3, no. 1 (November 11, 2020): 48. http://dx.doi.org/10.3390/environsciproc3010048.
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In recent years, anthropogenic actions have intensified forest fragmentation, causing several damages to the landscape’s natural components, propagating the loss of biodiversity. This study aims to present an analysis of the forest fragments in a conservation unit located at southern of Brazil. The evaluation was carried out for the years 1998, 2008, and 2018, by using landscape metrics and classification of remote sensing imagery of the Landsat satellite. The following metrics were analyzed: area and edge, shape, core area, and aggregation. The results indicated an increase of 16.88% in the total area of vegetation, and the percentage of fragments increased from 16.16% to 18.89%. The number of fragments decreased, resulting in an increase of the mean area in 5.4 ha. The percentage of vegetation under border effect changed from 40.2% to 37.1%. In 1998, the average nearest neighbor distance was 155.4 m, and in 2018, 149.7 m. However, this distance is still classified as a high degree of isolation, which hinders the movement of organisms and the dispersion of species. Thus, all the analyzed metrics indicated a decrease in the fragmentation, except for the edge density metric, in which its increase of 1.86 pointed to a lower degree of conservation during the analyzed period. A study of this nature is important as it provides subsidies for future researches and can contribute to action strategies to be adopted in the management plan of the area.
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Fernandes, Bianca, and Ligia Batista. "Spatial-Temporal Analysis of the Forest Fragments Surrounding a Conservation Unit in the Southern Region of Brazil." Environmental Sciences Proceedings 3, no. 1 (November 11, 2020): 48. http://dx.doi.org/10.3390/iecf2020-07876.
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In recent years, anthropogenic actions have intensified forest fragmentation, causing several damages to the landscape’s natural components, propagating the loss of biodiversity. This study aims to present an analysis of the forest fragments in a conservation unit located at southern of Brazil. The evaluation was carried out for the years 1998, 2008, and 2018, by using landscape metrics and classification of remote sensing imagery of the Landsat satellite. The following metrics were analyzed: area and edge, shape, core area, and aggregation. The results indicated an increase of 16.88% in the total area of vegetation, and the percentage of fragments increased from 16.16% to 18.89%. The number of fragments decreased, resulting in an increase of the mean area in 5.4 ha. The percentage of vegetation under border effect changed from 40.2% to 37.1%. In 1998, the average nearest neighbor distance was 155.4 m, and in 2018, 149.7 m. However, this distance is still classified as a high degree of isolation, which hinders the movement of organisms and the dispersion of species. Thus, all the analyzed metrics indicated a decrease in the fragmentation, except for the edge density metric, in which its increase of 1.86 pointed to a lower degree of conservation during the analyzed period. A study of this nature is important as it provides subsidies for future researches and can contribute to action strategies to be adopted in the management plan of the area.
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Cordue, P. L. "Fishing intensity metrics for use in overfishing determination." ICES Journal of Marine Science 69, no. 4 (February 27, 2012): 615–23. http://dx.doi.org/10.1093/icesjms/fss036.
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Abstract Cordue, P. L. 2012. Fishing intensity metrics for use in overfishing determination. – ICES Journal of Marine Science, 69: 615–623. The issue of constructing a technically correct fishing intensity metric from the output of a stock assessment model is considered. Four metrics of annual overall “fishing intensity” are defined. The metrics are applicable to age- or length-structured stock assessment models, which may, or may not, include complex spatial and temporal structure in the population and the fisheries. Two of the metrics are termed “direct” as they are calculated from the model output in the given year. Equivalent annual U is a number-based exploitation rate, and equivalent annual F is an average fishing mortality rate. The other two metrics, equilibrium stock depletion (ESD) and spawning potential ratio (SPR), measure fishing intensity in terms of the potential long-term effect on the stock (via 1–ESD and 1–SPR). The use of the metrics for overfishing determination is illustrated with a simple, spatial, two-fishery model. Summary statistics, which are sometimes used as a measure of fishing intensity, such as total catch over a reference biomass, or a number-weighted F are shown to be technically invalid for overfishing determination. The common approach, for virtual population analysis assessments, of using an average F over a specified age range is also discussed.
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Guillaume, Alain, Laurent Goffart, and Denis Pélisson. "Learning from cerebellar lesions about the temporal and spatial aspects of saccadic control." Behavioral and Brain Sciences 22, no. 4 (August 1999): 687–88. http://dx.doi.org/10.1017/s0140525x99352158.
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In the model proposed by Findlay & Walker, the programming of saccadic eye movements is achieved by two parallel processes, one dedicated to the coding of saccade metrics (Where) and the other controlling saccade initiation (When). One outcome of the “winner-take-all” characteristics of the salience map, the main node of the model, is an independence between the metrics and the latency of saccades. We report on some observations, made in the head-unrestrained cat under pathological conditions, of a correlation between accuracy and latency of saccadic gaze shifts. To account for such a correlation, the link between metrics specification (Where) and saccade triggering (When) should be amended in the model.
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Zhang, Shengchao, Liam J. Spoletini, Benjamin P. Gold, Victoria L. Morgan, Baxter P. Rogers, and Catie Chang. "Interindividual Signatures of fMRI Temporal Fluctuations." Cerebral Cortex 31, no. 10 (April 26, 2021): 4450–63. http://dx.doi.org/10.1093/cercor/bhab099.
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Abstract The complexity and variability of human brain activity, such as quantified from Functional Magnetic Resonance Imaging (fMRI) time series, have been widely studied as potential markers of healthy and pathological states. However, the extent to which fMRI temporal features exhibit stable markers of inter-individual differences in brain function across healthy young adults is currently an open question. In this study, we draw upon two widely used time-series measures—a nonlinear complexity measure (sample entropy; SampEn) and a spectral measure of low-frequency content (fALFF)—to capture dynamic properties of resting-state fMRI in a large sample of young adults from the Human Connectome Project. We observe that these two measures are closely related, and that both generate reproducible patterns across brain regions over four different fMRI runs, with intra-class correlations of up to 0.8. Moreover, we find that both metrics can uniquely differentiate subjects with high identification rates (ca. 89%). Canonical correlation analysis revealed a significant relationship between multivariate brain temporal features and behavioral measures. Overall, these findings suggest that regional profiles of fMRI temporal characteristics may provide stable markers of individual differences, and motivate future studies to further probe relationships between fMRI time series metrics and behavior.
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Gaye, Bamba, Gabriel S. Tajeu, Lucile Offredo, Maxime Vignac, Stacey Johnson, Frédérique Thomas, and Xavier Jouven. "Temporal trends of cardiovascular health factors among 366 270 French adults." European Heart Journal - Quality of Care and Clinical Outcomes 6, no. 2 (July 22, 2019): 138–46. http://dx.doi.org/10.1093/ehjqcco/qcz038.
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Abstract Aims We aimed to investigate time trends in cardiovascular health (CVH) metrics in the population at large, as well as in important subgroups. Methods and results In this study, we used a community-based sample of 366 270 adults from France who had a standardized examination to assess cardiovascular risk factors between 1992 and 2011 (20 years). Cardiovascular health metrics categorized into ideal, intermediate, and poor categories were computed using smoking, physical activity, body mass index, total cholesterol, blood glucose, and blood pressure. Matching on age, sex, and depression across 5-year periods (1992–96, 1997–2001, 2002–06, and 2007–11) was performed in order to correct for the sociodemographic differences between the examinations at different periods of times. Mean age across all four time periods was 44.7 (SD 13) years and 38% (138 228) were women. Overall, few participants (≤3.5%) met all six ideal CVH metrics at any time point. The prevalence of meeting ≥5 ideal CVH metrics increased from 6.7% in 1992–96 to 15.0% in 2007–11 (P < 0.001). A significant improvement in CVH (meeting ≥5 ideal CVH metrics) from 1992 to 2011 was observed among younger (from 7.5% to 16.6%) and older individuals (from 1.3% to 4.2%), men (from 4.4% to 11.8%) and women (from 10.4% to 20.1%), those with low (from 9.1% to 10.4%) and high education status (from 15% to 18.1%) and those with (from 5.1% to 12.7%) and without depressive symptoms (from 6.8% to 15.1%). However, the rate of improvement was steepest in the most affluent group in comparison with those with lower socio-economic status. Conclusion Overall CVH improved from 1992 until 2006 and slightly decreased between 2006 and 2011 in French adults. From 1992 until 2006, the improvement in CVH was less pronounced among those with low socio-economic status as compared to those with a higher socio-economic status.
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Gough, Albert, Andrew M. Stern, John Maier, Timothy Lezon, Tong-Ying Shun, Chakra Chennubhotla, Mark E. Schurdak, Steven A. Haney, and D. Lansing Taylor. "Biologically Relevant Heterogeneity: Metrics and Practical Insights." SLAS DISCOVERY: Advancing the Science of Drug Discovery 22, no. 3 (January 6, 2017): 213–37. http://dx.doi.org/10.1177/2472555216682725.
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Heterogeneity is a fundamental property of biological systems at all scales that must be addressed in a wide range of biomedical applications, including basic biomedical research, drug discovery, diagnostics, and the implementation of precision medicine. There are a number of published approaches to characterizing heterogeneity in cells in vitro and in tissue sections. However, there are no generally accepted approaches for the detection and quantitation of heterogeneity that can be applied in a relatively high-throughput workflow. This review and perspective emphasizes the experimental methods that capture multiplexed cell-level data, as well as the need for standard metrics of the spatial, temporal, and population components of heterogeneity. A recommendation is made for the adoption of a set of three heterogeneity indices that can be implemented in any high-throughput workflow to optimize the decision-making process. In addition, a pairwise mutual information method is suggested as an approach to characterizing the spatial features of heterogeneity, especially in tissue-based imaging. Furthermore, metrics for temporal heterogeneity are in the early stages of development. Example studies indicate that the analysis of functional phenotypic heterogeneity can be exploited to guide decisions in the interpretation of biomedical experiments, drug discovery, diagnostics, and the design of optimal therapeutic strategies for individual patients.
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Koch, Julian, Mehmet Cüneyd Demirel, and Simon Stisen. "The SPAtial EFficiency metric (SPAEF): multiple-component evaluation of spatial patterns for optimization of hydrological models." Geoscientific Model Development 11, no. 5 (May 15, 2018): 1873–86. http://dx.doi.org/10.5194/gmd-11-1873-2018.
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Abstract. The process of model evaluation is not only an integral part of model development and calibration but also of paramount importance when communicating modelling results to the scientific community and stakeholders. The modelling community has a large and well-tested toolbox of metrics to evaluate temporal model performance. In contrast, spatial performance evaluation does not correspond to the grand availability of spatial observations readily available and to the sophisticate model codes simulating the spatial variability of complex hydrological processes. This study makes a contribution towards advancing spatial-pattern-oriented model calibration by rigorously testing a multiple-component performance metric. The promoted SPAtial EFficiency (SPAEF) metric reflects three equally weighted components: correlation, coefficient of variation and histogram overlap. This multiple-component approach is found to be advantageous in order to achieve the complex task of comparing spatial patterns. SPAEF, its three components individually and two alternative spatial performance metrics, i.e. connectivity analysis and fractions skill score, are applied in a spatial-pattern-oriented model calibration of a catchment model in Denmark. Results suggest the importance of multiple-component metrics because stand-alone metrics tend to fail to provide holistic pattern information. The three SPAEF components are found to be independent, which allows them to complement each other in a meaningful way. In order to optimally exploit spatial observations made available by remote sensing platforms, this study suggests applying bias insensitive metrics which further allow for a comparison of variables which are related but may differ in unit. This study applies SPAEF in the hydrological context using the mesoscale Hydrologic Model (mHM; version 5.8), but we see great potential across disciplines related to spatially distributed earth system modelling.
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Bodrogi, P., QT Vinh, and TQ Khanh. "Correlations among lighting quality metrics for interior lighting." Lighting Research & Technology 51, no. 8 (December 18, 2018): 1192–207. http://dx.doi.org/10.1177/1477153518818856.
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Correlations between selected lighting quality metrics derived from the spectrum were computed and interpreted for a representative set of interior light source spectra. Metrics of brightness and the melanopic effect were strongly correlated with each other but not with the metrics of colour quality. Results can be used to establish a two-dimensional diagram with criterion values to ensure the general user acceptance of a lighting system. This diagram can be extended in the future by further metrics describing light intensity and spatial and temporal light distributions. Relationships between lighting quality metrics and colorimetric quantities as well as photoreceptor signal values are also shown.
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Duncan, P. H. "The effect of temporal image filters on observer-dependent contrast metrics." IEEE Transactions on Image Processing 6, no. 4 (April 1997): 617–21. http://dx.doi.org/10.1109/83.563328.
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Danilo de Miranda Regis, Carlos, Italo de Pontes Oliveira, Jose Vinicius de Miranda Cardoso, and Marcelo Sampaio de Alencar. "Design of Objective Video Quality Metrics Using Spatial and Temporal Informations." IEEE Latin America Transactions 13, no. 3 (March 2015): 790–95. http://dx.doi.org/10.1109/tla.2015.7069106.
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Eicher-Miller, Heather A., Saul Gelfand, Youngha Hwang, Edward Delp, Anindya Bhadra, and Jiaqi Guo. "Distance metrics optimized for clustering temporal dietary patterning among U.S. adults." Appetite 144 (January 2020): 104451. http://dx.doi.org/10.1016/j.appet.2019.104451.
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Pedersen, Mangor, Amir Omidvarnia, Jennifer M. Walz, Andrew Zalesky, and Graeme D. Jackson. "Spontaneous brain network activity: Analysis of its temporal complexity." Network Neuroscience 1, no. 2 (June 2017): 100–115. http://dx.doi.org/10.1162/netn_a_00006.
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The brain operates in a complex way. The temporal complexity underlying macroscopic and spontaneous brain network activity is still to be understood. In this study, we explored the brain’s complexity by combining functional connectivity, graph theory, and entropy analyses in 25 healthy people using task-free functional magnetic resonance imaging. We calculated the pairwise instantaneous phase synchrony between 8,192 brain nodes for a total of 200 time points. This resulted in graphs for which time series of clustering coefficients (the “cliquiness” of a node) and participation coefficients (the between-module connectivity of a node) were estimated. For these two network metrics, sample entropy was calculated. The procedure produced a number of results: (1) Entropy is higher for the participation coefficient than for the clustering coefficient. (2) The average clustering coefficient is negatively related to its associated entropy, whereas the average participation coefficient is positively related to its associated entropy. (3) The level of entropy is network-specific to the participation coefficient, but not to the clustering coefficient. High entropy for the participation coefficient was observed in the default-mode, visual, and motor networks. These results were further validated using an independent replication dataset. Our work confirms that brain networks are temporally complex. Entropy is a good candidate metric to explore temporal network alterations in diseases with paroxysmal brain disruptions, including schizophrenia and epilepsy.
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Chadha, Aman, John Britto, and M. Mani Roja. "iSeeBetter: Spatio-temporal video super-resolution using recurrent generative back-projection networks." Computational Visual Media 6, no. 3 (July 20, 2020): 307–17. http://dx.doi.org/10.1007/s41095-020-0175-7.
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Abstract Recently, learning-based models have enhanced the performance of single-image super-resolution (SISR). However, applying SISR successively to each video frame leads to a lack of temporal coherency. Convolutional neural networks (CNNs) outperform traditional approaches in terms of image quality metrics such as peak signal to noise ratio (PSNR) and structural similarity (SSIM). On the other hand, generative adversarial networks (GANs) offer a competitive advantage by being able to mitigate the issue of a lack of finer texture details, usually seen with CNNs when super-resolving at large upscaling factors. We present iSeeBetter, a novel GAN-based spatio-temporal approach to video super-resolution (VSR) that renders temporally consistent super-resolution videos. iSeeBetter extracts spatial and temporal information from the current and neighboring frames using the concept of recurrent back-projection networks as its generator. Furthermore, to improve the “naturality” of the super-resolved output while eliminating artifacts seen with traditional algorithms, we utilize the discriminator from super-resolution generative adversarial network. Although mean squared error (MSE) as a primary loss-minimization objective improves PSNR/SSIM, these metrics may not capture fine details in the image resulting in misrepresentation of perceptual quality. To address this, we use a four-fold (MSE, perceptual, adversarial, and total-variation loss function. Our results demonstrate that iSeeBetter offers superior VSR fidelity and surpasses state-of-the-art performance.
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Behrman, Alison, Sarah Hargus Ferguson, Ali Akhund, and Mariola Moeyaert. "The Effect of Clear Speech on Temporal Metrics of Rhythm in Spanish-Accented Speakers of English." Language and Speech 62, no. 1 (November 7, 2017): 5–29. http://dx.doi.org/10.1177/0023830917737109.
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This paper presents a comparative analysis of temporal rhythm in native American English talkers and Spanish-accented English talkers producing clear (hyperarticulated) speech and typical, conversational-style speech. Five acoustic measures of comparative vocalic and consonantal interval duration (“temporal metrics”) were obtained from speech samples of 40 adult men and women (half native and half Spanish-accented talkers). In conversational-style speech, vocalic-based metrics differed significantly between native and Spanish-accented talkers, consistent with phonotactic differences between the two native languages. In clear speech, however, all metric values from the Spanish-accented talkers became more English-like and no longer differed significantly from those observed in the native English talkers. Post-hoc analysis revealed that native English talkers increased the duration of both weak and strong vowels in clear speech, whereas the Spanish-accented talkers increased the duration of strong vowels without changing the duration of weak vowels. Listener ease of understanding, as perceived by monolingual English speakers, was significantly improved in clear- compared with conversational-style speech for all talkers. The acoustic data help to explain the changes that result from use of clear speech in nonnative speakers. Together with the improved listener ease of understanding, these data strongly support the further exploration of clear speech as a clinical tool to improve prosody and hence, interpersonal communication, in nonnative speakers.
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Rife, Daran L., and Christopher A. Davis. "Verification of Temporal Variations in Mesoscale Numerical Wind Forecasts." Monthly Weather Review 133, no. 11 (November 1, 2005): 3368–81. http://dx.doi.org/10.1175/mwr3052.1.
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Abstract The authors address a particular example of the general question of whether high-resolution forecasts provide additional deterministic skill beyond what can be achieved with a coarser-resolution model. To this end, real-time forecasts using the fifth-generation Pennsylvania State University–NCAR Mesoscale Model (MM5) with grid increments of 30 and 3.3 km are compared over a domain centered on the complex terrain region of southern New Mexico during the 1 June 2002 to 1 June 2003 period. The authors use time series of surface data to evaluate the relative ability of the two forecasts to capture significant temporal variations of wind. The authors hypothesize that the additional detail and structure provided by high resolution becomes a “liability” when the forecasts are scored by traditional verification metrics, because such metrics sharply penalize forecasts with small temporal or spatial errors of predicted features. Thus, a set of verification metrics is designed that is increasingly tolerant of timing errors for temporal changes of wind. The authors find that the barrier-normal (i.e., zonal) wind component over complex terrain reveals the greatest improvement in skill due to increased horizontal resolution for the cases considered here. In addition, the fine-grid forecasts better replicate the cessation of drainage flow or onset of upslope flow near and within complex terrain. The most surprising result is the marginal benefit of the higher resolution over valley locations not in immediate proximity to the mountain slopes, even though the valley is only about 60 km across (east–west). Overall, the gains in forecast accuracy from finer grid spacing are generally incremental, but increase with greater tolerance for timing errors, culminating in the greatest improvement for forecasts of temporal variance.
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Chen, C. F., N. T. Son, C. R. Chen, L. Y. Chang, and S. H. Chiang. "RICE CROP MAPPING USING SENTINEL-1A PHENOLOGICAL METRICS." ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLI-B8 (June 23, 2016): 863–65. http://dx.doi.org/10.5194/isprsarchives-xli-b8-863-2016.
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Rice is the most important food crop in Vietnam, providing food more than 90 million people and is considered as an essential source of income for majority of rural populations. Monitoring rice-growing areas is thus important to developing successful strategies for food security in the country. This paper aims to develop an approach for crop acreage estimation from multi-temporal Sentinel-1A data. We processed the data for two main cropping seasons (e.g., winter–spring, summer–autumn) in the Mekong River Delta (MRD), Vietnam through three main steps: (1) data pre-processing, (3) rice classification based on crop phenological metrics, and (4) accuracy assessment of the mapping results. The classification results compared with the ground reference data indicated the overall accuracy of 86.2% and Kappa coefficient of 0.72. These results were reaffirmed by close correlation between the government’s rice area statistics for such crops (R<sup>2</sup> > 0.95). The values of relative error in area obtained for the winter–spring and summer–autumn were -3.6% and 6.7%, respectively. This study demonstrates the potential application of multi-temporal Sentinel-1A data for rice crop mapping using information of crop phenology in the study region.
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Chen, C. F., N. T. Son, C. R. Chen, L. Y. Chang, and S. H. Chiang. "RICE CROP MAPPING USING SENTINEL-1A PHENOLOGICAL METRICS." ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLI-B8 (June 23, 2016): 863–65. http://dx.doi.org/10.5194/isprs-archives-xli-b8-863-2016.
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Rice is the most important food crop in Vietnam, providing food more than 90 million people and is considered as an essential source of income for majority of rural populations. Monitoring rice-growing areas is thus important to developing successful strategies for food security in the country. This paper aims to develop an approach for crop acreage estimation from multi-temporal Sentinel-1A data. We processed the data for two main cropping seasons (e.g., winter–spring, summer–autumn) in the Mekong River Delta (MRD), Vietnam through three main steps: (1) data pre-processing, (3) rice classification based on crop phenological metrics, and (4) accuracy assessment of the mapping results. The classification results compared with the ground reference data indicated the overall accuracy of 86.2% and Kappa coefficient of 0.72. These results were reaffirmed by close correlation between the government’s rice area statistics for such crops (R<sup>2</sup> > 0.95). The values of relative error in area obtained for the winter–spring and summer–autumn were -3.6% and 6.7%, respectively. This study demonstrates the potential application of multi-temporal Sentinel-1A data for rice crop mapping using information of crop phenology in the study region.
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Champion, Curtis, Alistair J. Hobday, Xuebin Zhang, Gretta T. Pecl, and Sean R. Tracey. "Changing windows of opportunity: past and future climate-driven shifts in temporal persistence of kingfish (Seriola lalandi) oceanographic habitat within south-eastern Australian bioregions." Marine and Freshwater Research 70, no. 1 (2019): 33. http://dx.doi.org/10.1071/mf17387.
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Climate-driven shifts in species distributions are occurring rapidly within marine systems and are predicted to continue under climate change. To effectively adapt, marine resource users require information relevant to their activities at decision-making timescales. We model oceanographic habitat suitability for kingfish (Seriola lalandi) from south-eastern Australia using multiple environmental variables at monthly time steps over the period 1996–2040. Habitat predictions were used to quantify the temporal persistence (months per year) of suitable oceanographic habitat within six coastal bioregions. A decline in temporal habitat persistence is predicted for the northernmost (equatorward) bioregion, whereas increases are predicted for the three southernmost (poleward) bioregions. We suggest that temporal habitat persistence is an important metric for climate change adaptation because it provides fishery-relevant information. Our methods demonstrate how novel metrics relevant to climate adaptation can be derived from predictions of species’ environmental habitats, and are appropriate for the management of fisheries resources and protection of high conservation value species under future climate change.
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Dechaicha, Assoule, Adel Daikh, and Djamel Alkama. "Monitoring and Landscape Quantification of Uncontrolled Urbanisation in Oasis Regions: The Case of Adrar City in Algeria." Journal of Contemporary Urban Affairs 5, no. 2 (July 12, 2021): 209–19. http://dx.doi.org/10.25034/ijcua.2021.v5n2-5.
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Nowadays, uncontrolled urbanisation is one of the major problems facing Algerian oasis regions. The monitoring and evaluation of its landscape transformations remain a key step for any oasis sustainability project. This study highlights the evolution of spatial growth in the city of Adrar in southern Algeria during the period 1986-2016 by establishing a Spatio-temporal mapping and landscape quantification. The methodological approach is based on a multi-temporal analysis of Landsat satellite images for 1986, 1996, 2006 and 2016, and the application of landscape metrics. The results show two opposite spatial trends: significant growth of built-up areas against an excessive loss of palm groves. The landscape metrics allowed the identification of a progressive fragmentation process characterising the palm groves. Thus, the findings of this study show the utility of satellite imagery and landscape metrics approach for monitoring urbanisation patterns and assessing their impacts on oasis ecosystems.
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Dubois, C., M. M. Mueller, C. Pathe, T. Jagdhuber, F. Cremer, C. Thiel, and C. Schmullius. "CHARACTERIZATION OF LAND COVER SEASONALITY IN SENTINEL-1 TIME SERIES DATA." ISPRS Annals of Photogrammetry, Remote Sensing and Spatial Information Sciences V-3-2020 (August 3, 2020): 97–104. http://dx.doi.org/10.5194/isprs-annals-v-3-2020-97-2020.
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Abstract. In this study, we analyze Sentinel-1 time series data to characterize the observed seasonality of different land cover classes in eastern Thuringia, Germany and to identify multi-temporal metrics for their classification. We assess the influence of different polarizations and different pass directions on the multi-temporal backscatter profile. The novelty of this approach is the determination of phenological parameters, based on a tool that has been originally developed for optical imagery. Furthermore, several additional multitemporal metrics are determined for the different classes, in order to investigate their separability for potential multi-temporal classification schemes. The results of the study show a seasonality for vegetation classes, which differs depending on the considered class: whereas pastures and broad-leaved forests show a decrease of the backscatter in VH polarization during summer, an increase of the backscatter in VH polarization is observed for coniferous forest. The observed seasonality is discussed together with meteorological information (precipitation and air temperature). Furthermore, a dependence of the backscatter of the pass direction (ascending/descending) is observed particularly for the urban land cover classes. Multi-temporal metrics indicate a good separability of principal land cover classes such as urban, agricultural and forested areas, but further investigation and use of seasonal parameters is needed for a distinct separation of specific forest sub-classes such as coniferous and deciduous.