Journal articles: 'Distribution Shift'

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Lameris, Thomas K., Jeroen Hoekendijk, Geert Aarts, Aline Aarts, Andrew M. Allen, Louise Bienfait, Allert I. Bijleveld, et al. "Migratory vertebrates shift migration timing and distributions in a warming Arctic." Animal Migration 8, no. 1 (January 1, 2021): 110–31. http://dx.doi.org/10.1515/ami-2020-0112.

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Abstract Climate warming in the Arctic has led to warmer and earlier springs, and as a result, many food resources for migratory animals become available earlier in the season, as well as become distributed further northwards. To optimally profit from these resources, migratory animals are expected to arrive earlier in the Arctic, as well as shift their own spatial distributions northwards. Here, we review literature to assess whether Arctic migratory birds and mammals already show shifts in migration timing or distribution in response to the warming climate. Distribution shifts were most prominent in marine mammals, as expected from observed northward shifts of their resources. At least for many bird species, the ability to shift distributions is likely constrained by available habitat further north. Shifts in timing have been shown in many species of terrestrial birds and ungulates, as well as for polar bears. Within species, we found strong variation in shifts in timing and distributions between populations. Ou r review thus shows that many migratory animals display shifts in migration timing and spatial distribution in reaction to a warming Arctic. Importantly, we identify large knowledge gaps especially concerning distribution shifts and timing of autumn migration, especially for marine mammals. Our understanding of how migratory animals respond to climate change appears to be mostly limited by the lack of long-term monitoring studies.

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Klopčič, Matija, Andrej Rozman, and Andrej Bončina. "Evidence of a Climate-Change-Induced Shift in European Beech Distribution: An Unequal Response in the Elevation, Temperature and Precipitation Gradients." Forests 13, no. 8 (August 17, 2022): 1311. http://dx.doi.org/10.3390/f13081311.

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Climate is a strong predictor of the geographic distribution of tree species, and thus climate change may trigger shifts in the distribution of a tree species and/or its demographic structure. In the study, we aim to comprehensively compare the distributions of four life stages of European beech (Fagus sylvatica) (i.e., regeneration, recruitment, young trees and mature trees) in forests in Slovenia, Central Europe, which are characterized by strong gradients of elevation (ELV), temperature (TEMP) and precipitation (PREC) to detect possible shifts in distribution and demography. Beech life stages were surveyed on 3366 plots. To depict disparities between ELV, TEMP and PREC distributions of beech life stages, we applied several non-parametric methods: basic statistical tests to study differences in medians, means, and 1st and 9th deciles; generalized additive models to study shifts in the optimum; and extreme value analysis to study shifts at the trailing and leading edges. A substantial shift in juvenile beech stages upward and toward colder sites was detected. However, the shift was not uniform along the distributions; the most significant shift was detected at the leading edge of ELV (+73 m) and TEMP (−2.6 °C), but surprisingly there was no beech movement identified at the trailing edge. The observed shift may be a result of the interplay between climate change, high spatial variability in microclimate, unexceptional droughts in the recent past, changes in forest use and possible limitations in the migration ability of beech and its adaptation capacity.

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Takesue, Hiroki, Toshimori Honjo, Kiyoshi Tamaki, and Yasuhiro Tokura. "Differential phase shift-quantum key distribution." IEEE Communications Magazine 47, no. 5 (May 2009): 102–6. http://dx.doi.org/10.1109/mcom.2009.4939284.

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Yuki, Kazuhiro. "SECTORAL SHIFT, WEALTH DISTRIBUTION, AND DEVELOPMENT." Macroeconomic Dynamics 12, no. 4 (September 2008): 527–59. http://dx.doi.org/10.1017/s1365100508070296.

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Two phenomena are widely observed when an economy departs from an underdeveloped state and starts rapid economic growth. One is the shift of production, employment, and consumption from the traditional sector to the modern sector, and the other is a large increase in educational levels of the population. The question is why some economies have succeeded in such structural change, but others do not. To examine the question, an overlapping generations (OLG) model that explicitly takes into account the sectoral shift and human capital accumulation as sources of development is constructed. It is shown that, for a successful structural change, an economy must start with a wealth distribution that gives rise to an adequate size of the “middle class.” Once the economy initiates the “take-off,” the sectoral shift and human capital growth continue until it reaches the steady state with high income and equal distribution. However, when the productivity of the traditional sector is low, irrespective of the initial distribution and the productivity of the modern sector, it fails in the sectoral shift and ends up in one of steady states with low income and high inequality. Thus, sufficient productivity of the traditional sector is a prerequisite for development.

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Laine, Ilpo. "Zero distribution of some shift polynomials." Journal of Mathematical Analysis and Applications 469, no. 2 (January 2019): 808–26. http://dx.doi.org/10.1016/j.jmaa.2018.09.036.

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Butt, Mehwish, Hafiza Farwa Amin, Javed Iqbal, Maqbool Hussain Sial, Najam-ul Hassan, and Mueen-ud-Din Azad. "Homogeneously Weighted Moving Average Control Chart for Rayleigh Distribution." Bulletin of Business and Economics (BBE) 12, no. 3 (November 24, 2023): 366–84. http://dx.doi.org/10.61506/01.00043.

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In this paper, we have proposed Homogeneously Weighted Moving Average (HWMA) control chart for Rayleigh distribution. The Average Run Length (ARL1) is used to evaluate the performance of the proposed HWMA control charts. The ARL1 performance of HWMA control chart is compared to the Exponentially weighted moving average (EWMA) control charts with respect to the different shift size (i.e. 10%, 15%, 20%, 30%, 40% increase and decrease in shift). The results are calculated using sample size n=5. It is observed that with the increase in shift proposed HWMA chart shows more efficient results i.e. ARL1 values decrease with the increase in shifts. It is found that the proposed HWMA chart for Rayleigh distribution outperforms the existing EWMA control chart.

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Yu, Xu, Miao Yu, Li-xun Xu, Jing Yang, and Zhi-qiang Xie. "Training Classifiers under Covariate Shift by Constructing the Maximum Consistent Distribution Subset." Mathematical Problems in Engineering 2015 (2015): 1–9. http://dx.doi.org/10.1155/2015/302815.

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The assumption that the training and testing samples are drawn from the same distribution is violated under covariate shift setting, and most algorithms for the covariate shift setting try to first estimate distributions and then reweight samples based on the distributions estimated. Due to the difficulty of estimating a correct distribution, previous methods can not get good classification performance. In this paper, we firstly present two types of covariate shift problems. Rather than estimating the distributions, we then desire an effective method to select a maximum subset following the target testing distribution based on feature space split from the auxiliary set or the target training set. Finally, we prove that our subset selection method can consistently deal with both scenarios of covariate shift. Experimental results demonstrate that training a classifier with the selected maximum subset exhibits good generalization ability and running efficiency over those of traditional methods under covariate shift setting.

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A Hassan, Mohamed, and Samia SA Hassan. "pp Coulomb Phase Shift for Different Proton Charge Distributions." Australian Journal of Physics 45, no. 5 (1992): 635. http://dx.doi.org/10.1071/ph920635.

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The dependence of the pp Coulomb phase shift on the form of the proton charge distribution function is studied and discussed. The uniform, exponential and Gaussian distributions are used. The dependence- on the form of the charge distribution for impact parameter values less than the radius of the proton is clear. The charge distribution effect leads to a decrease in the absolute value of the Coulomb phase shift.

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Ye, Nanyang, Lin Zhu, Jia Wang, Zhaoyu Zeng, Jiayao Shao, Chensheng Peng, Bikang Pan, Kaican Li, and Jun Zhu. "Certifiable Out-of-Distribution Generalization." Proceedings of the AAAI Conference on Artificial Intelligence 37, no. 9 (June 26, 2023): 10927–35. http://dx.doi.org/10.1609/aaai.v37i9.26295.

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Machine learning methods suffer from test-time performance degeneration when faced with out-of-distribution (OoD) data whose distribution is not necessarily the same as training data distribution. Although a plethora of algorithms have been proposed to mitigate this issue, it has been demonstrated that achieving better performance than ERM simultaneously on different types of distributional shift datasets is challenging for existing approaches. Besides, it is unknown how and to what extent these methods work on any OoD datum without theoretical guarantees. In this paper, we propose a certifiable out-of-distribution generalization method that provides provable OoD generalization performance guarantees via a functional optimization framework leveraging random distributions and max-margin learning for each input datum. With this approach, the proposed algorithmic scheme can provide certified accuracy for each input datum's prediction on the semantic space and achieves better performance simultaneously on OoD datasets dominated by correlation shifts or diversity shifts. Our code is available at https://github.com/ZlatanWilliams/StochasticDisturbanceLearning.

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Inoue, Kyo. "Differential Phase-Shift Quantum Key Distribution Systems." IEEE Journal of Selected Topics in Quantum Electronics 21, no. 3 (May 2015): 109–15. http://dx.doi.org/10.1109/jstqe.2014.2360362.

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Hatefi, Elham, Hossein Karshenas, and Peyman Adibi. "Distribution shift alignment in visual domain adaptation." Expert Systems with Applications 235 (January 2024): 121210. http://dx.doi.org/10.1016/j.eswa.2023.121210.

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Zheng, Xiaofeng, Pengxiang Gao, and ShuoXin Zhang. "The distribution shifts of Pinus armandii and its response to temperature and precipitation in China." PeerJ 5 (September 15, 2017): e3807. http://dx.doi.org/10.7717/peerj.3807.

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Background The changing climate, particularly in regard to temperature and precipitation, is already affecting tree species’ distributions. Pinus armandii, which dominates on the Yungui Plateau and in the Qinba Mountains in China, is of economic, cultural and ecological value. We wish to test the correlations between the distribution shift of P. armandii and changing climate, and figure out how it tracks future climate change. Methods We sampled the surface soil at sites throughout the distribution of P. armandii to compare the relative abundance of pollen to the current percent cover of plant species. This was used to determine possible changes in the distribution P. armandii. Given the hilly terrain, elevation was considered together with temperature and precipitation as variables correlated with distribution shifts of P. armandii. Results We show that P. armandii is undergoing change in its geographic range, including retraction, a shift to more northern areas and from the upper high part of the mountains to a lower-altitude part in hilly areas. Temperature was the strongest correlate of this distribution shift. Elevation and precipitation were also both significantly correlated with distribution change of P. armandii, but to a lesser degree than temperature. Conclusion The geographic range of P. armandii has been gradually decreasing under the influence of climate change. This provides evidence of the effect of climate change on trees at the species level and suggests that at least some species will have a limited ability to track the changing climate.

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Gómez-Déniz, E., L. Gómez, and H. W. Gómez. "The Slashed-Rayleigh Fading Channel Distribution." Mathematical Problems in Engineering 2019 (February 11, 2019): 1–14. http://dx.doi.org/10.1155/2019/2719849.

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We propose an alternative distribution for modelling fading-shadowing wireless channels. This distribution presents certain advantages over the Rayleigh-lognormal distribution and the K distribution and has proved useful in the setting described. We obtain closed-form expressions for the average channel capacity and for the average bit error rate of differential phase-shift keying and of minimum shift keying when the new distribution is used. This distribution can be obtained exactly as the sum of mutual independent Gaussian stochastic processes, because it must represent the simulation of the fading channel; that is, it simulates the signal envelope. Finally, we describe practical applications of this distribution, comparing it with the Rayleigh-lognormal and K distributions.

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Spanbauer, Trisha L., Craig R. Allen, David G. Angeler, Tarsha Eason, Sherilyn C. Fritz, Ahjond S. Garmestani, Kirsty L. Nash, Jeffery R. Stone, Craig A. Stow, and Shana M. Sundstrom. "Body size distributions signal a regime shift in a lake ecosystem." Proceedings of the Royal Society B: Biological Sciences 283, no. 1833 (June 29, 2016): 20160249. http://dx.doi.org/10.1098/rspb.2016.0249.

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Communities of organisms, from mammals to microorganisms, have discontinuous distributions of body size. This pattern of size structuring is a conservative trait of community organization and is a product of processes that occur at multiple spatial and temporal scales. In this study, we assessed whether body size patterns serve as an indicator of a threshold between alternative regimes. Over the past 7000 years, the biological communities of Foy Lake (Montana, USA) have undergone a major regime shift owing to climate change. We used a palaeoecological record of diatom communities to estimate diatom sizes, and then analysed the discontinuous distribution of organism sizes over time. We used Bayesian classification and regression tree models to determine that all time intervals exhibited aggregations of sizes separated by gaps in the distribution and found a significant change in diatom body size distributions approximately 150 years before the identified ecosystem regime shift. We suggest that discontinuity analysis is a useful addition to the suite of tools for the detection of early warning signals of regime shifts.

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Landis, Michael, Erika J. Edwards, and Michael J. Donoghue. "Modeling Phylogenetic Biome Shifts on a Planet with a Past." Systematic Biology 70, no. 1 (August 28, 2020): 86–107. http://dx.doi.org/10.1093/sysbio/syaa045.

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Abstract The spatial distribution of biomes has changed considerably over deep time, so the geographical opportunity for an evolutionary lineage to shift into a new biome may depend on how the availability and connectivity of biomes has varied temporally. To better understand how lineages shift between biomes in space and time, we developed a phylogenetic biome shift model in which each lineage shifts between biomes and disperses between regions at rates that depend on the lineage’s biome affinity and location relative to the spatial distribution of biomes at any given time. To study the behavior of the biome shift model in an empirical setting, we developed a literature-based representation of paleobiome structure for three mesic forest biomes, six regions, and eight time strata, ranging from the Late Cretaceous (100 Ma) through the present. We then fitted the model to a time-calibrated phylogeny of 119 Viburnum species to compare how the results responded to various realistic or unrealistic assumptions about paleobiome structure. Ancestral biome estimates that account for paleobiome dynamics reconstructed a warm temperate (or tropical) origin of Viburnum, which is consistent with previous fossil-based estimates of ancestral biomes. Imposing unrealistic paleobiome distributions led to ancestral biome estimates that eliminated support for tropical origins, and instead inflated support for cold temperate ancestry throughout the warmer Paleocene and Eocene. The biome shift model we describe is applicable to the study of evolutionary systems beyond Viburnum, and the core mechanisms of our model are extensible to the design of richer phylogenetic models of historical biogeography and/or lineage diversification. We conclude that biome shift models that account for dynamic geographical opportunities are important for inferring ancestral biomes that are compatible with our understanding of Earth history.[Ancestral states; biome shifts; historical biogeography; niche conservatism; phylogenetics]

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Soultan, Alaaeldin, Diego Pavón-Jordán, Ute Bradter, Brett K. Sandercock, Wesley M. Hochachka, Alison Johnston, Jon Brommer, et al. "The future distribution of wetland birds breeding in Europe validated against observed changes in distribution." Environmental Research Letters 17, no. 2 (February 1, 2022): 024025. http://dx.doi.org/10.1088/1748-9326/ac4ebe.

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Abstract Wetland bird species have been declining in population size worldwide as climate warming and land-use change affect their suitable habitats. We used species distribution models (SDMs) to predict changes in range dynamics for 64 non-passerine wetland birds breeding in Europe, including range size, position of centroid, and margins. We fitted the SDMs with data collected for the first European Breeding Bird Atlas and climate and land-use data to predict distributional changes over a century (the 1970s–2070s). The predicted annual changes were then compared to observed annual changes in range size and range centroid over a time period of 30 years using data from the second European Breeding Bird Atlas. Our models successfully predicted ca. 75% of the 64 bird species to contract their breeding range in the future, while the remaining species (mostly southerly breeding species) were predicted to expand their breeding ranges northward. The northern margins of southerly species and southern margins of northerly species, both, predicted to shift northward. Predicted changes in range size and shifts in range centroids were broadly positively associated with the observed changes, although some species deviated markedly from the predictions. The predicted average shift in core distributions was ca. 5 km yr−1 towards the north (5% northeast, 45% north, and 40% northwest), compared to a slower observed average shift of ca. 3.9 km yr−1. Predicted changes in range centroids were generally larger than observed changes, which suggests that bird distribution changes may lag behind environmental changes leading to ‘climate debt’. We suggest that predictions of SDMs should be viewed as qualitative rather than quantitative outcomes, indicating that care should be taken concerning single species. Still, our results highlight the urgent need for management actions such as wetland creation and restoration to improve wetland birds’ resilience to the expected environmental changes in the future.

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Cheung, William W. L., Jessica J. Meeuwig, Ming Feng, Euan Harvey, Vicky W. Y. Lam, Tim Langlois, Dirk Slawinski, Chaojiao Sun, and Daniel Pauly. "Climate-change induced tropicalisation of marine communities in Western Australia." Marine and Freshwater Research 63, no. 5 (2012): 415. http://dx.doi.org/10.1071/mf11205.

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A major observed and predicted impact of climate change on marine species is the poleward shift in their distributions and the resulting changes in community structure. Here, we used a Dynamic Bioclimate Envelope Model to project range shift of exploited marine fishes and invertebrates in Western Australia. We combined published data and expert knowledge to predict current species distributions for 30 tropical, sub-tropical and temperate species that occur along the coast of Western Australia. Using outputs from both a Regional Oceanographic Model and a Global Circulation Model, we simulated change in the distribution of each species. Our study shows that under the SRES (Special Report for Emission Scenarios) A1B scenario, the median rate of distribution shift is around 19 km decade–1 towards higher latitudes and 9 m deeper decade–1 by 2055 relative to 2005. As a result, species gains and losses are expected along the south coast and north coast of Western Australia, respectively. Also, the coast of Western Australia is expected to experience a ‘tropicalisation’ of the marine community in the future, with increasing dominance of warmer-water species. Such changes in species assemblages may have large ecological and socio-economic implications through shifts in fishing grounds and unexpected trophic effects.

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Cheng, Luling, Xue Yang, Luliang Tang, Qian Duan, Zihan Kan, Xia Zhang, and Xinyue Ye. "Spatiotemporal Analysis of Taxi-Driver Shifts Using Big Trace Data." ISPRS International Journal of Geo-Information 9, no. 4 (April 24, 2020): 281. http://dx.doi.org/10.3390/ijgi9040281.

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In taxi management, taxi-driver shift behaviors play a key role in arranging the operation of taxis, which affect the balance between the demand and supply of taxis and the parking spaces. At the same time, these behaviors influence the daily travel of citizens. An analysis of the distribution of taxi-driver shifts, therefore, contributes to transportation management. Compared to the previous research using the real shift records, this study focuses on the spatiotemporal analysis of taxi-driver shifts using big trace data. A two-step strategy is proposed to automatically identify taxi-driver shifts from big trace data without the information of drivers’ identities. The first step is to pick out the frequent spatiotemporal sequential patterns from all parking events based on the spatiotemporal sequence analysis. The second step is to construct a Gaussian mixture model based on prior knowledge for further identifying taxi-driver shifts from all frequent spatiotemporal sequential patterns. The spatiotemporal distribution of taxi-driver shifts is analyzed based on two indicators, namely regional taxi coverage intensity and taxi density. Taking the city of Wuhan as an example, the experimental results show that the identification precision and recall rate of taxi-driver shift events based on the proposed method can achieve about 95% and 90%, respectively, by using big taxi trace data. The occurrence time of taxi-driver shifts in Wuhan mainly has two high peak periods: 1:00 a.m. to 4:00 a.m. and 4:00 p.m. to 5:00 p.m. Although taxi-driver shift behaviors are prohibited during the evening peak hour based on the regulation issued by Wuhan traffic administration, experimental results show that there are still some drivers in violation of this regulation. By analyzing the spatial distribution of taxi-driver shifts, we find that most taxi-driver shifts distribute in central urban areas such as Wuchang and Jianghan district.

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Lone, Showkat Ahmad, Zahid Rasheed, Sadia Anwar, Majid Khan, Syed Masroor Anwar, and Sana Shahab. "Enhanced fault detection models with real-life applications." AIMS Mathematics 8, no. 8 (2023): 19595–636. http://dx.doi.org/10.3934/math.20231000.

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<abstract> <p>Nonconforming events are rare in high-quality processes, and the time between events (TBE) may follow a skewed distribution, such as the gamma distribution. This study proposes one- and two-sided triple homogeneously weighted moving average charts for monitoring TBE data modeled by the gamma distribution. These charts are labeled as the THWMA TBE charts. Monte Carlo simulations are performed to approximate the run length distribution of the one- and two-sided THWMA TBE charts. The THWMA TBE charts are compared to competing charts like the DHWMA TBE, HWMA TBE, THWMA TBE, DEWMA TBE, and EWMA TBE charts at a single shift and over a range of shifts. For the single shift comparison, the average run length (ARL) and standard deviation run length (SDRL) measures are used, whereas the extra quadratic loss (EQL), relative average run length (RARL) and performance comparison index (PCI) measures are employed for a range of shifts comparison. The comparison reveals that the THWMA TBE charts outperform the competing charts at a single shift as well as at a certain range of shifts. Finally, two real-life data applications are presented to evaluate the applicability of the THWMA TBE charts in practical situations, one with boring machine failure data and the other with hospital stay time for traumatic brain injury patients.</p> </abstract>

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Kuo, Chang Hsin, and Jhy Cherng Tsai. "New Tolerance Analysis Model for Normal Mean Shift in Manufacturing Process." Materials Science Forum 594 (August 2008): 339–50. http://dx.doi.org/10.4028/www.scientific.net/msf.594.339.

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In this paper, we discuss the tolerance analysis methods for the component with a mean shift or drift. A new tolerance analysis model that assumes the mean shift in normal distribution rather than in uniform distribution is proposed. Simulation shows that the difference between the uniform distribution and normal distribution is 1.7%, which can be ignored, for mean shift to one standard deviation (σ). However, the difference becomes significant when the mean shift increases. The difference increases to 5.2% with 1.5σ shift, to 10.9% for 2σ shift, and up to 30.4% for 3σ shift. As normal distribution is a better model for statistical mean shift in manufacturing process, this investigation shows that the proposed tolerance analysis model can give a better model compared to conventional models.

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Vestfals, Cathleen D., Lorenzo Ciannelli, and Gerald R. Hoff. "Changes in habitat utilization of slope-spawning flatfish across a bathymetric gradient." ICES Journal of Marine Science 73, no. 7 (July 1, 2016): 1875–89. http://dx.doi.org/10.1093/icesjms/fsw112.

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Abstract Understanding how fish distributions may change in response to environmental variability is important for effective management of fish populations, as predicted climate change will likely alter their habitat use and population dynamics. This research focused on two commercially- and ecologically-important flatfish species in the eastern Bering Sea (EBS), Greenland halibut ( Reinhardtius hippoglossoides ) and Pacific halibut ( Hippoglossus stenolepis ), which may be especially sensitive to climate-induced shifts in habitat due to strong seasonally and ontogenetically variable distributions. We analysed data from fishery-dependent and fishery-independent sources to determine how environmental variability influenced habitat use, thus gaining a uniquely comprehensive range of seasonal and geographic coverage of each species’ distribution. Greenland and Pacific halibut exhibited strong and contrasting responses to changes in temperature on the shelf, with catches decreasing and increasing, respectively, beyond 1 °C. The effect of temperature was not as prominent along the slope, suggesting that slope habitats may provide some insulation from shelf-associated environmental variability, particularly for Greenland halibut. With warming, Greenland halibut exhibited more of a bathymetric shift in distribution, while the shift was more latitudinal for Pacific halibut. Our results suggest that habitat partitioning may, in part, explain differences in Greenland and Pacific halibut distributions. This research adds to our understanding of how the distributions of two fish species at opposite extremes of their ranges in the EBS – Greenland halibut at the southernmost edge and Pacific halibut at the northernmost edge – may shift in relation to a changing ocean environment.

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Dwornicka, Renata, Andrii Goroshko, and Jacek Pietraszek. "The Smoothed Bootstrap Fine-Tuning." System Safety: Human - Technical Facility - Environment 1, no. 1 (March 1, 2019): 716–23. http://dx.doi.org/10.2478/czoto-2019-0091.

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AbstractThe bootstrap method is a well-known method to gather a full probability distribution from the dataset of a small sample. The simple bootstrap i.e. resampling from the raw dataset often leads to a significant irregularities in a shape of resulting empirical distribution due to the discontinuity of a support. The remedy for these irregularities is the smoothed bootstrap: a small random shift of source points before each resampling. This shift is controlled by specifically selected distributions. The key issue is such parameter settings of these distributions to achieve the desired characteristics of the empirical distribution. This paper describes an example of this procedure.

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Krishnan, Arjun, Firas Rassoul-Agha, and Timo Seppäläinen. "Geodesic length and shifted weights in first-passage percolation." Communications of the American Mathematical Society 3, no. 5 (May 18, 2023): 209–89. http://dx.doi.org/10.1090/cams/18.

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We study first-passage percolation through related optimization problems over paths of restricted length. The path length variable is in duality with a shift of the weights. This puts into a convex duality framework old observations about the convergence of the normalized Euclidean length of geodesics due to Hammersley and Welsh, Smythe and Wierman, and Kesten, and leads to new results about geodesic length and the regularity of the shape function as a function of the weight shift. For points far enough away from the origin, the ratio of the geodesic length and the ℓ 1 \ell ^1 distance to the endpoint is uniformly bounded away from one. The shape function is a strictly concave function of the weight shift. Atoms of the weight distribution generate singularities, that is, points of nondifferentiability, in this function. We generalize to all distributions, directions and dimensions an old singularity result of Steele and Zhang for the planar Bernoulli case. When the weight distribution has two or more atoms, a dense set of shifts produces singularities. The results come from a combination of the convex duality, the shape theorems of the different first-passage optimization problems, and modification arguments.

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Yang, Qinghua, Shou-jiang Tang, Ruonan Wu, and Juliana Yang. "Dynamic Shift in the Distribution of Colorectal Cancer." American Journal of Gastroenterology 106 (October 2011): S154. http://dx.doi.org/10.14309/00000434-201110002-00392.

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Horoshko, D. B., D. I. Pustakhod, and S. Ya Kilin. "Time-shift quantum key distribution with decoy states." Optics and Spectroscopy 108, no. 3 (March 2010): 336–42. http://dx.doi.org/10.1134/s0030400x10030045.

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Horoshko, D. B., D. I. Pustakhod, and S. Ya Kilin. "Time-shift quantum key distribution: Sensitivity to losses." Optics and Spectroscopy 111, no. 5 (November 2011): 685–88. http://dx.doi.org/10.1134/s0030400x11110129.

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Parr, Gerard, and Kevin Curran. "A paradigm shift in the distribution of multimedia." Communications of the ACM 43, no. 6 (June 2000): 103–9. http://dx.doi.org/10.1145/336460.336486.

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Ji, Xingquan, Qi Liu, Yongjin Yu, Shuxian Fan, and Na Wu. "Distribution network reconfiguration based on vector shift operation." IET Generation, Transmission & Distribution 12, no. 13 (July 31, 2018): 3339–45. http://dx.doi.org/10.1049/iet-gtd.2018.0099.

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Hackstein, M., and A. Dewald. "Velocity distribution in Recoil-Distance Doppler-Shift experiments." Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment 738 (February 2014): 93–98. http://dx.doi.org/10.1016/j.nima.2013.11.047.

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Strukov, T. S. "Shift estimation and forms of Von Mises distribution." Journal of Mathematical Sciences 189, no. 6 (February 28, 2013): 992–96. http://dx.doi.org/10.1007/s10958-013-1242-8.

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Zhechev, D., S. Atanassova, L. Yourukova, and K. Kolentsov. "Optogalvanic Indication of Small Continuous Spectrum Distribution Shift." Spectroscopy Letters 30, no. 5 (July 1997): 843–47. http://dx.doi.org/10.1080/00387019708001633.

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Odedina, Joe. "Online Streaming: A Paradigm Shift for Nollywood Movie Distribution." International Journal of Current Research in the Humanities 27, no. 1 (April 30, 2024): 159–73. http://dx.doi.org/10.4314/ijcrh.v27i1.10.

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The Nigerian movie distribution and exhibition business has undergone major transformation in the last few years due to technological innovation. The study is about Nollywood paradigm shift from hard copy movie distribution to online streaming services. The aim is to ascertain why producers are moving to soft screening through online pay-to-view platforms. The objectives were to find out if this new trend is financially beneficial to the producers and whether it will likely continue in the future. The study adopted qualitative methods to interrogate existing data on some of the most popular Nollywood films released online by Netflix. This is based on a snap-shot of Netflix’s popularity chart in the month of October, 2020 and news of cinema theatre films release around the same period. The findings are that the online distribution deals must have been profitable for the producers, judging by repeated use by some of them and others enlisting in the business. The expanding scope of Nollywood producers using these online streaming platforms for distributions of their work suggests the likelihood of a continuing process. The study concludes that this is a mutually beneficial relationship between local producers and online business global entities. It, therefore, recommends that Nollywood producers avoid signing exclusive deals with online distributors only. This will allow home-grown cinema theatres to be financially rewarding to prevent the nation’s cinema theatre chains from collapsing due to redundancy.

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Lin, Tzong-Han, Kai-Wei Chan, Feng-Chuan Hsu, Chung-Chi Lin, and Hui-Yun Tseng. "Putative source and niche shift pattern of a new alien ant species (Odontomachus troglodytes) in Taiwan." PeerJ 11 (February 6, 2023): e14718. http://dx.doi.org/10.7717/peerj.14718.

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Alien species may pose substantial impacts on biodiversity around the globe through international trade and travel. A niche shift hypothesis was proposed to explain the adaptive change of alien or invasive species in new habitats. However, whether niche shifts occur in alien species likely depends on both characteristics inherent to the species itself and its original distribution. Here we identified a newly exotic trap-jaw ant (Odontomachus troglodytes) in Taiwan by morphological and phylogenetic analyses. The possible distribution range and the niche shift pattern were evaluated using ecological niche modelling. The results indicated that exotic O. troglodytes in the newly distributed area displayed a significant niche shift with low niche overlap and high niche expansion. This study reveals a long-distance invasive event from central Africa to Southeast Asia (more than 10,000 km) and predicts the potential distribution range of this new alien species in Taiwan.

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Rezaei, Ashkan, Anqi Liu, Omid Memarrast, and Brian D. Ziebart. "Robust Fairness Under Covariate Shift." Proceedings of the AAAI Conference on Artificial Intelligence 35, no. 11 (May 18, 2021): 9419–27. http://dx.doi.org/10.1609/aaai.v35i11.17135.

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Making predictions that are fair with regard to protected attributes (race, gender, age, etc.) has become an important requirement for classification algorithms. Existing techniques derive a fair model from sampled labeled data relying on the assumption that training and testing data are identically and independently drawn (iid) from the same distribution. In practice, distribution shift can and does occur between training and testing datasets as the characteristics of individuals interacting with the machine learning system change. We investigate fairness under covariate shift, a relaxation of the iid assumption in which the inputs or covariates change while the conditional label distribution remains the same. We seek fair decisions under these assumptions on target data with unknown labels. We propose an approach that obtains the predictor that is robust to the worst-case testing performance while satisfying target fairness requirements and matching statistical properties of the source data. We demonstrate the benefits of our approach on benchmark prediction tasks.

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Fan, Wei, Pengyang Wang, Dongkun Wang, Dongjie Wang, Yuanchun Zhou, and Yanjie Fu. "Dish-TS: A General Paradigm for Alleviating Distribution Shift in Time Series Forecasting." Proceedings of the AAAI Conference on Artificial Intelligence 37, no. 6 (June 26, 2023): 7522–29. http://dx.doi.org/10.1609/aaai.v37i6.25914.

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The distribution shift in Time Series Forecasting (TSF), indicating series distribution changes over time, largely hinders the performance of TSF models. Existing works towards distribution shift in time series are mostly limited in the quantification of distribution and, more importantly, overlook the potential shift between lookback and horizon windows. To address above challenges, we systematically summarize the distribution shift in TSF into two categories. Regarding lookback windows as input-space and horizon windows as output-space, there exist (i) intra-space shift, that the distribution within the input-space keeps shifted over time, and (ii) inter-space shift, that the distribution is shifted between input-space and output-space. Then we introduce, Dish-TS, a general neural paradigm for alleviating distribution shift in TSF. Specifically, for better distribution estimation, we propose the coefficient net (Conet), which can be any neural architectures, to map input sequences into learnable distribution coefficients. To relieve intra-space and inter-space shift, we organize Dish-TS as a Dual-Conet framework to separately learn the distribution of input- and output-space, which naturally captures the distribution difference of two spaces. In addition, we introduce a more effective training strategy for intractable Conet learning. Finally, we conduct extensive experiments on several datasets coupled with different state-of-the-art forecasting models. Experimental results show Dish-TS consistently boosts them with a more than 20% average improvement. Code is available at https://github.com/weifantt/Dish-TS.

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González-Hernández, Antonio, Diego Nieto-Lugilde, Julio Peñas, and Francisca Alba-Sánchez. "Lean Pattern in an Altitude Range Shift of a Tree Species: Abies pinsapo Boiss." Forests 12, no. 11 (October 25, 2021): 1451. http://dx.doi.org/10.3390/f12111451.

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Organisms modify their geographical distributions in response to changes in environmental conditions, or modify their affinity to such conditions, to avoid extinction. This study explored the altitudinal shift of Abies pinsapo Boiss. in the Baetic System. We analysed the potential distribution of the realised and reproductive niches of A. pinsapo populations in the Ronda Mountains (Southern Spain) by using species distribution models (SDMs) for two life stages within the current populations. Then, we calculated the species’ potential altitudinal shifts and identified the areas in which the processes of persistence and migration predominated. The realised and reproductive niches of A. pinsapo are different to one another, which may indicate a displacement in its altitudinal distribution owing to changes in the climatic conditions of the Ronda Mountains. The most unfavourable conditions for the species indicate a trailing edge (~110 m) at the lower limit of its distribution and a leading edge (~55 m) at the upper limit. Even though the differences in the altitudinal shifts between the trailing and leading edges will not cause the populations to become extinct in the short term, they may threaten their viability if the conditions that are producing the contraction at the lower limit persist in the long term.

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Katano, Izumi, Hiromune Mitsuhashi, Hideyuki Doi, Yu Isobe, and Tadashi Oishi. "Distribution and drift dispersal dynamics of a caddisfly grazer in response to resource abundance and its ontogeny." Royal Society Open Science 4, no. 1 (January 2017): 160732. http://dx.doi.org/10.1098/rsos.160732.

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Stream grazers have a major impact on food web structure and the productivity of stream ecosystems; however, studies on the longitudinal (upstream versus downstream) and temporal changes in their drift dynamics and resulting distributions remain limited. Here, we investigated the longitudinal and temporal distributions and drift propensity of a trichopteran grazer, the caddisfly, Micrasema quadriloba , during its life cycle in a Japanese stream. The distribution of larvae significantly shifted downstream during the fifth instar larval stage during late winter; with periphyton abundance (i.e. their food source) showing similar shifts downstream. Therefore, our results show that the drift dispersal the caddisfly occurs in response to decline in available food resources (i.e. food-resource scarcity) and an increase in food requirements by growing individuals. Furthermore, our results show that this observed longitudinal shift in larval distribution varies through their life cycle, because the drift dispersal of fifth instar larvae was greater than that of immature larvae. The correlation between periphyton abundance and drift propensity of fourth instar larvae was not statistically significant, whereas that of fifth instar larvae was significantly negative. In conclusion, we detected an ontogenetic shift in drift propensity, which might explain the longitudinal and temporal distributions of this species.

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Walther, Gian-Reto, Silje Berger, and Martin T. Sykes. "An ecological ‘footprint’ of climate change." Proceedings of the Royal Society B: Biological Sciences 272, no. 1571 (June 28, 2005): 1427–32. http://dx.doi.org/10.1098/rspb.2005.3119.

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Recently, there has been increasing evidence of species' range shifts due to changes in climate. Whereas most of these shifts relate ground truth biogeographic data to a general warming trend in regional or global climate data, we here present a reanalysis of both biogeographic and bioclimatic data of equal spatio-temporal resolution, covering a time span of more than 50 years. Our results reveal a coherent and synchronous shift in both species' distribution and climate. They show not only a shift in the northern margin of a species, which is in concert with gradually increasing winter temperatures in the area, they also confirm the simulated species' distribution changes expected from a bioclimatic model under the recent, relatively moderate climate change.

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Aguilée, Robin, Gaël Raoul, François Rousset, and Ophélie Ronce. "Pollen dispersal slows geographical range shift and accelerates ecological niche shift under climate change." Proceedings of the National Academy of Sciences 113, no. 39 (September 12, 2016): E5741—E5748. http://dx.doi.org/10.1073/pnas.1607612113.

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Species may survive climate change by migrating to track favorable climates and/or adapting to different climates. Several quantitative genetics models predict that species escaping extinction will change their geographical distribution while keeping the same ecological niche. We introduce pollen dispersal in these models, which affects gene flow but not directly colonization. We show that plant populations may escape extinction because of both spatial range and ecological niche shifts. Exact analytical formulas predict that increasing pollen dispersal distance slows the expected spatial range shift and accelerates the ecological niche shift. There is an optimal distance of pollen dispersal, which maximizes the sustainable rate of climate change. These conclusions hold in simulations relaxing several strong assumptions of our analytical model. Our results imply that, for plants with long distance of pollen dispersal, models assuming niche conservatism may not accurately predict their future distribution under climate change.

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Engelhard, Georg H., John K. Pinnegar, Laurence T. Kell, and Adriaan D. Rijnsdorp. "Nine decades of North Sea sole and plaice distribution." ICES Journal of Marine Science 68, no. 6 (April 11, 2011): 1090–104. http://dx.doi.org/10.1093/icesjms/fsr031.

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Abstract Engelhard, G. H., Pinnegar, J. K., Kell, L. T., and Rijnsdorp, A. D. 2011. Nine decades of North Sea sole and plaice distribution. – ICES Journal of Marine Science, 68: 1090–1104. Recent studies based mainly on research survey data suggest that within the North Sea, sole Solea solea and plaice Pleuronectes platessa have exhibited distribution shifts in recent decades—on average southward for sole and northward to deeper waters for plaice. Various hypotheses may account for such shifts, including climate change effects and more intensive fishing in southern and shallower waters; but the relatively short time-span of datasets analysed so far (∼3 decades) has complicated the separation of these two effects. We have made use of a unique dataset of catch and effort data for British North Sea trawlers; these cover nine decades (spanning the period 1913–2007) and are spatially detailed by ICES rectangle (0.5° latitude by 1° longitude). We quantify, for the first time, long-term distribution changes of North Sea sole and plaice over a period approaching a century, and demonstrate that the distribution shift in plaice was attributable to climate change rather than to fishing, but that both climate and fishing played a role in the distribution shift of sole. The discussion also highlights the potential impact of additional factors, including eutrophication, prey availability, and habitat modification.

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Lavenda, B. H. "Doppler Line Broadening from the Asymptotic Cauchy Distribution." Zeitschrift für Naturforschung A 48, no. 4 (April 1, 1993): 557–59. http://dx.doi.org/10.1515/zna-1993-0403.

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Abstract The half-width of Doppler broadening is derived without assuming Maxwell's distribution for the velocities of the radiating atoms. In the absence of Doppler broadening there is only natural radiation broadening, and by thermalizing the asymptotic Cauchy distribution one obtains asymp-totic double exponential distributions for the largest (blue) and smallest (red) values of the frequency shift. These are the relevant extreme value distributions for largest and smallest values. Since the mean values are opposite and equal there is a zero shift in the line, while the standard deviation gives an expression for the half-width to within 2% of the Doppler half-width obtained from the Maxwellian when the damping coefficient is taken as the ratio of the natural radiation damping coefficient to the fine structure constant.

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Guan, Lisha, Yong Chen, Kevin W. Staples, Jie Cao, and Bai Li. "The influence of complex structure on the spatial dynamics of Atlantic cod (Gadus morhua) in the Gulf of Maine." ICES Journal of Marine Science 74, no. 9 (April 27, 2017): 2379–88. http://dx.doi.org/10.1093/icesjms/fsx064.

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Abstract Atlantic cod (Gadus morhua) in the Gulf of Maine (GOM) is an iconic marine fishery stock that has experienced a substantial distributional shift since the mid-1990s. A geostatistical delta-generalized linear mixed model was utilized to hindcast yearly season-specific distributions of GOM cod. These distributions were calculated using the spring and fall bottom trawl survey data for the stock, along with cell-based bathymetry and bottom temperature data for the study area for the years 1982–2013. The centre of stock distribution (the centre of gravity), spatial extent in latitude and longitude, area occupied and median habitat temperature were estimated annually to quantify changes in the spatial dynamics of GOM cod. Time series of these distributional metrics were then used to evaluate the influences of climate change and density-dependent habitat selection on GOM cod’s distribution. Results showed that the rapid southwestward shift in the stock distribution after the late 1990s could not simply be attributed to decreasing stock abundance or warming bottom temperatures. The observed shift in cod distribution requires further investigation on whether it is possibly a result of other factors, like fluctuating productivity among subpopulations.

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Alexander, Chinago B., and Vincent E. Weli. "Statistical Analyses of Rainfall Distribution: A Check on Climatic Shift." Journal of Progress in Engineering and Physical Science 2, no. 1 (March 2023): 1–12. http://dx.doi.org/10.56397/jpeps.2023.03.01.

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The study Statistical Analyse of Rainfall Distribution: A check on Climate Shift is concerned with using table values and graph to visually compare rainfall distribution over different climatic cycles. To achieve this, rainfall data from Nigeria Meteorological Agency archive was extracted for analysis. The study observed that only two months had mean rainfall less than 51mm. It was also observed that rainfall occurrence decreases over the years, as indicated by the negative trend line. The study among other things discovered that the double maxima as a result of August dry spell has reduced significantly, thereby increasing run-off. This paper observed that the time of the years is significantly related to rainfall occurrence. The month of August had more improved rainfall throughout the period of study. The rate of dispersion of mean annual rainfall from the station mean is an indication of the reliability of rainfall or otherwise. This work opined that change in climate will lead to a complete shift in RF distributions; therefore, the activities that were influenced by RF will be affected positively or in a negative way in the future. This work recommends that agriculture calendar of the study area need to be changed therefore farmers need to adopt new farming techniques as RF distribution change. There agricultural calendar needs to also change.

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Tkachuk, O. I., V. V. Lobanov, and M. I. Terebinska. "Core-Level States of Single-Electron Adsorption Complexes Ge on Si (001) (42)." Фізика і хімія твердого тіла 16, no. 2 (June 15, 2015): 316–21. http://dx.doi.org/10.15330/pcss.16.2.316-321.

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Calculations (DFT, B3LYP, 6-31 G**) chemical shifts core-level components of germanium atoms, which are included in the surface layer of cluster Si96H84•Ge2, modeling complex molecular adsorption on germanium faces reconstructed Si(001)(4´2), showed that the magnitude of the shift depends on the relative position of atoms Ge. When introducing a single atom in a crystal germanium substrate, this shift is positive, and the introduction of two atoms leads to negative chemical shift. Given the interpretation of the results based on the charge distribution in clusters, the so-called electrostatic approximation.

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Xu, Pengcheng, Boyu Wang, and Charles Ling. "Class Overwhelms: Mutual Conditional Blended-Target Domain Adaptation." Proceedings of the AAAI Conference on Artificial Intelligence 37, no. 3 (June 26, 2023): 3036–44. http://dx.doi.org/10.1609/aaai.v37i3.25407.

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Current methods of blended targets domain adaptation (BTDA) usually infer or consider domain label information but underemphasize hybrid categorical feature structures of targets, which yields limited performance, especially under the label distribution shift. We demonstrate that domain labels are not directly necessary for BTDA if categorical distributions of various domains are sufficiently aligned even facing the imbalance of domains and the label distribution shift of classes. However, we observe that the cluster assumption in BTDA does not comprehensively hold. The hybrid categorical feature space hinders the modeling of categorical distributions and the generation of reliable pseudo labels for categorical alignment. To address these, we propose a categorical domain discriminator guided by uncertainty to explicitly model and directly align categorical distributions P(Z|Y). Simultaneously, we utilize the low-level features to augment the single source features with diverse target styles to rectify the biased classifier P(Y|Z) among diverse targets. Such a mutual conditional alignment of P(Z|Y) and P(Y|Z) forms a mutual reinforced mechanism. Our approach outperforms the state-of-the-art in BTDA even compared with methods utilizing domain labels, especially under the label distribution shift, and in single target DA on DomainNet.

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Bell, Richard J., David E. Richardson, Jonathan A. Hare, Patrick D. Lynch, and Paula S. Fratantoni. "Disentangling the effects of climate, abundance, and size on the distribution of marine fish: an example based on four stocks from the Northeast US shelf." ICES Journal of Marine Science 72, no. 5 (December 11, 2014): 1311–22. http://dx.doi.org/10.1093/icesjms/fsu217.

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Abstract Climate change and fishing can have major impacts on the distribution of natural marine resources. Climate change alters the distribution of suitable habitat, forcing organisms to shift their range or attempt to survive under suboptimal conditions. Fishing reduces the abundance of marine populations and truncates their age structure leading to range contractions or shifts. Along the east coast of the United States, there have been major changes in fish populations due to the impacts of fishing and subsequent regulations, as well as changes in the climate. Black sea bass, scup, summer flounder, and winter flounder are important commercial and recreational species, which utilize inshore and offshore waters on the northeast shelf. We examined the distributions of the four species with the Northeast Fisheries Science Center trawl surveys to determine if the along-shelf centres of biomass had changed over time and if the changes were attributed to changes in temperature or fishing pressure through changes in abundance and length structure. Black sea bass, scup, and summer flounder exhibited significant poleward shifts in distributions in at least one season while the Southern New England/Mid-Atlantic Bight stock of winter flounder did not shift. Generalized additive modelling indicated that the changes in the centres of biomass for black sea bass and scup in spring were related to climate, while the change in the distribution of summer flounder was largely attributed to a decrease in fishing pressure and an expansion of the length–age structure. While the changes in ocean temperatures will have major impacts on the distribution of marine taxa, the effects of fishing can be of equivalent magnitude and on a more immediate time scale. It is important for management to take all factors into consideration when developing regulations for natural marine resources.

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Solow, Andrew, Andrew Beet, Uri Roll, and Lewi Stone. "A test for a shift in the boundary of the geographical range of a species." Biology Letters 10, no. 2 (February 2014): 20130808. http://dx.doi.org/10.1098/rsbl.2013.0808.

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One predicted impact of climate change is a poleward shift in the boundaries of species ranges. Existing methods for identifying such a boundary shift based on changes in the observed pattern of occupancy within a grid of cells are sensitive to changes in the overall rate of sightings and their latitudinal distribution that are unconnected to a boundary shift. A formal test for a boundary shift is described that allows for such changes. The test is applied to detect northward shifts in the northern boundary of the Essex skipper ( Thymelicus lineola ) butterfly and the European goldfinch ( Carduelis carduelis ) in Great Britain. A shift is detected in the latter case but not in the former. Results from a simulation study are presented showing that the test performs well.

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Alexeev, Ivan A., and Alexey A. Khartov. "On convergence and compactness in variation with shift of discrete probability laws." Vestnik of Saint Petersburg University. Mathematics. Mechanics. Astronomy 8, no. 3 (2021): 385–93. http://dx.doi.org/10.21638/spbu01.2021.301.

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We consider a class of discrete distribution functions, whose characteristic functions are separated from zero, i. e. their absolute values are greater than positive constant on the real line. The class is rather wide, because it contains discrete infinitely divisible distribution functions, functions of lattice distributions, whose characteristic functions have no zeroes on the real line, and also distribution functions with a jump greater than 1/2. Recently the authors showed that characteristic functions of elements of this class admit the Lévy-Khinchine type representations with non-monotonic spectral function. Thus our class is included in the set of so called quasi-infinitely divisible distribution functions. Using these representation the authors also obtained limit and compactness theorems with convergence in variation for the sequences from this class. This note is devoted to similar results concerning convergence and compactness but with weakened convergence in variation. Replacing of type of convergence notably expands applicability of the results.

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Corcoran, J. N., and U. Schneider. "SHIFT AND SCALE COUPLING METHODS FOR PERFECT SIMULATION." Probability in the Engineering and Informational Sciences 17, no. 3 (June 6, 2003): 277–303. http://dx.doi.org/10.1017/s0269964803173019.

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We describe and develop a variation on a layered multishift coupler due to Wilson that uses a slice sampling procedure to allow one to obtain potentially common draws from two different distributions. Our main application is coupling sample paths of Markov chains for use in perfect sampling algorithms. The coupler is based on slicing density functions and we describe a “folding” mechanism as an attractive alternative to the accept/reject step commonly used in slice sampling algorithms. Applications of the coupler are given to storage models and to auto-gamma distribution sampling.

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Waringer-Löschenkohl, Andrea. "An experimental study of microhabitat selection and microhabitat shifts in European tadpoles." Amphibia-Reptilia 9, no. 3 (1988): 219–36. http://dx.doi.org/10.1163/156853888x00314.

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The presence or absence of heterospecific tadpoles or of vegetation and changes in population density influenced the microhabitat distribution of 5 sympatric tadpole species in laboratory experiments. Most species, except Hyla a. arborea, occupied the bottom of the aquaria. In some experiments the presence of vegetation caused a significant shift in the tadpole distribution towards the water surface. The presence of Pelobates fuscus, especially under higher density had a similar effect on tadpole distributions. In most species-combination tests one or both species shifted their distribution pattern due to the presence of the other species. In many cases this behaviour can be interpreted as spatial avoidance reaction especially in species which feed in the same water column in the field (Löschenkohl, 1986). The significance of microhabitat shifts as a mechanism to avoid competition is discussed.

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Journal articles on the topic 'Distribution Shift'

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