10,365 research outputs found
Computer model calibration with large non-stationary spatial outputs: application to the calibration of a climate model
Bayesian calibration of computer models tunes unknown input parameters by
comparing outputs with observations. For model outputs that are distributed
over space, this becomes computationally expensive because of the output size.
To overcome this challenge, we employ a basis representation of the model
outputs and observations: we match these decompositions to carry out the
calibration efficiently. In the second step, we incorporate the non-stationary
behaviour, in terms of spatial variations of both variance and correlations, in
the calibration. We insert two integrated nested Laplace
approximation-stochastic partial differential equation parameters into the
calibration. A synthetic example and a climate model illustration highlight the
benefits of our approach
Forest Clearcutting and Site-Preparation on a Saline Soil in East Texas: Impacts on Water Quality
Three 0.02 hectare plot-watersheds were installed on a saline soil in the Davy Crockett National Forest near Apple Springs, Texas. Each plot was installed with an H-flume, FW-1 automatic water level recorder, Coshocton N-1 runoff sampler, and two storage tanks. One watershed was undisturbed forested and served a control, one was clearcut without any site-preparation, and the third was clearcut, V-blade sheared, windrowed, and vegetation regrowth was prevented for the first 2 years. A total of 274 storms were recorded during the four-year study period, 1989-1992. Average annual sediment losses for the study period were 55, 197, and 1,530 kilograms per hectare per year for the control, commercial clearcut, and sheared plots, respectively. These losses are about average for most studies conducted in East Texas and the Southeast and are well below average losses for all land uses in the Southeast. Sediment losses and surface runoff were significantly greater from the sheared plot-watershed than from the control and the commercial clearcut plots. Employing Wischmeier and Smith’s (1978) long-term average Rvalue for the USLE overestimated annual sediment yield for the study period, while two shortcut models developed in the United States resulted in more accurate predictions and are good substitutes for the long-term R-value. Total losses in surface runoff of PO4, NO3, NO2, TKN, K, Ca, Mg, Na, Al, Fe, Zn, and Cu were higher on the site-prepared plot watershed than the other two. Losses of PO4, TKN, and NO2 were higher on the commercial clearcut plot than the control. Losses were not high enough to adversely affect forest productivity. Concentrations of elements were generally below established USEPA surface water quality standards and were not high enough to adversely affect plant growth
Field and intensity correlations in amplifying random media
We study local and nonlocal correlations of light transmitted through active
random media. The conventional approach results in divergence of ensemble
averaged correlation functions due to existence of lasing realizations. We
introduce conditional average for correlation functions by omitting the
divergent realizations. Our numerical simulation reveals that amplification
does not affect local spatial correlation. The nonlocal intensity correlations
are strongly magnified due to selective enhancement of the contributions from
long propagation paths. We also show that by increasing gain, the average mode
linewidth can be made smaller than the average mode spacing. This implies that
light transport through a diffusive random system with gain could exhibit some
similarities to that through a localized passive system, owing to dominant
influence of the resonant modes with narrow width.Comment: 5 pages, 4 figure
Recommended from our members
Consumer Video Understanding: A Benchmark Database and An Evaluation of Human and Machine Performance
Recognizing visual content in unconstrained videos has become a very important problem for many applications. Existingcorpora for video analysis lack scale and/or content diversity,and thus limited the needed progress in this critical area. In this paper, we describe and release a new database called CCV, containing 9,317 web videos over 20 semantic categories, including events like “baseball” and “parade”, scenes like “beach”, and objects like “cat”. The database was collected with extra care to ensure relevance to consumer interest and originality of video content without post-editing. Such videos typically have very little textual annotation and thus can benefit from the development of automatic content
analysis techniques. We used Amazon MTurk platform to perform manual annotation, and studied the behaviors and performance of human annotators on MTurk.We also compared the abilities in understanding consumer video content by humans and machines. For the latter, we implemented automatic classifiers using state-of-the-art multi-modal approach that achieved top performance in recent TRECVID multimedia event detection task. Results confirmed classifiers fusing audio and video features significantly outperform single-modality solutions. We also found that humans are much better at understanding categories of nonrigid objects such as “cat”, while current automatic techniques are relatively close to humans in recognizing categories that have distinctive background scenes or audio patterns
Assessing the impact of temporary housing sites on urban socio-spatial performance: the case of the Central Italy earthquake
This paperadvocatesa performance-based approach to the planningof temporary housing sites after sudden urban disasters. A “functionally graded”configurational analysis method is usedto assess,quantitatively and qualita-tively,thesocio-spatial impact of government-led housing assistance provisionacrossthe regional,urbanandneighbourhoodscales. To highlight the differentoutcomes achieved in different urban contextsby apparently similar housing re-covery plans, adiachronic comparative studyof four epicentral historic townshit by the 2016-2017Central Italyearthquakesis performed.The researchanalysestheconfigurationalpropertiesof these settlements at four critical points in time: before the disaster; right after it(emergency phase); during disaster recovery; after the reconstruction is completed. This paper builds on previous research on rapid urban modelling and economic spatial analysis workflows to respond to potential implementationchallenges,which include time constraints and geo-data availabilityissues after disasters. By using a real case scenario,this study seeks to demonstratethe potential benefitsof adopting the proposed multidimensional spatialanalysis methodto foster the delivery of integrated housing recovery so-lutions, which contribute to sustainable urban developmentTheseencompassin-forming, timely updating,and coordinatingstrategic, management,and opera-tional decisions related to the design and planningof temporary housing sites
Ecology & computer audition: applications of audio technology to monitor organisms and environment
Among the 17 Sustainable Development Goals (SDGs) proposed within the 2030 Agenda and adopted by all the United Nations member states, the 13th SDG is a call for action to combat climate change. Moreover, SDGs 14 and 15 claim the protection and conservation of life below water and life on land, respectively. In this work, we provide a literature-founded overview of application areas, in which computer audition – a powerful but in this context so far hardly considered technology, combining audio signal processing and machine intelligence – is employed to monitor our ecosystem with the potential to identify ecologically critical processes or states. We distinguish between applications related to organisms, such as species richness analysis and plant health monitoring, and applications related to the environment, such as melting ice monitoring or wildfire detection. This work positions computer audition in relation to alternative approaches by discussing methodological strengths and limitations, as well as ethical aspects. We conclude with an urgent call to action to the research community for a greater involvement of audio intelligence methodology in future ecosystem monitoring approaches
Universal Torsion-Induced Interaction from Large Extra Dimensions
We consider the Kaluza-Klein (KK) scenario in which only gravity exists in
the bulk. Without the assumption of symmetric connection, the presence of brane
fermions induces torsion. The result is a universal axial contact interaction
that dominates those induced by KK gravitons. This enhancement arises from a
large spin density on the brane. Using a global fit to Z-pole observables, we
find the 3 sigma bound on the scale of quantum gravity to be 28 TeV for n=2. If
Dirac or light sterile neutrinos are present, the data from SN1987A increase
the bound to \sqrt{n}M_S >= 210 TeV.Comment: 9 pages REVTeX, 1 postscript figure, uses axodraw.st
Forest Clearcutting and Site Preparation On A Saline Soil In East Texas: Impacts On Water Quality
Three 0.02 hectare plot-watersheds were installed on a saline soil in the Davy Crockett National
Forest near Apple Springs, Texas. Each plot was installed with an H-flume, FW-1 automatic water level
recorder, Coshocton N-1 runoff sampler, and two storage tanks. One watershed was undisturbed
forested and served a control, one was clearcut without any site-preparation, and the third was clearcut,
V-blade sheared, windrowed, and vegetation regrowth was prevented for the first 2 years. A total of 274
storms were recorded during the four-year study period, 1989-1992. Average annual sediment losses for
the study period were 55, 197, and 1,530 kilograms per hectare per year for the control, commercial
clearcut, and sheared plots, respectively. These losses are about average for most studies conducted in
East Texas and the Southeast and are well below average losses for all land uses in the Southeast.
Sediment losses and surface runoff were significantly greater from the sheared plot-watershed than from
the control and the commercial clearcut plots. Employing Wischmeier and Smith’s (1978) long-term
average R-value for the USLE overestimated annual sediment yield for the study period, while two
shortcut models developed in the United States resulted in more accurate predictions and are good
substitutes for the long-term R-value. Total losses in surface runoff of PO4, NO3, NO2, TKN, K, Ca, Mg,
Na, Al, Fe, Zn, and Cu were higher on the site-prepared plot watershed than the other two. Losses of
PO4, TKN, and NO2 were higher on the commercial clearcut plot than the control. Losses were not high
enough to adversely affect forest productivity. Concentrations of elements were generally below
established USEPA surface water quality standards and were not high enough to adversely affect plant
growth
- …