5,428 research outputs found
Domain Adaptive Transfer Attack (DATA)-based Segmentation Networks for Building Extraction from Aerial Images
Semantic segmentation models based on convolutional neural networks (CNNs)
have gained much attention in relation to remote sensing and have achieved
remarkable performance for the extraction of buildings from high-resolution
aerial images. However, the issue of limited generalization for unseen images
remains. When there is a domain gap between the training and test datasets,
CNN-based segmentation models trained by a training dataset fail to segment
buildings for the test dataset. In this paper, we propose segmentation networks
based on a domain adaptive transfer attack (DATA) scheme for building
extraction from aerial images. The proposed system combines the domain transfer
and adversarial attack concepts. Based on the DATA scheme, the distribution of
the input images can be shifted to that of the target images while turning
images into adversarial examples against a target network. Defending
adversarial examples adapted to the target domain can overcome the performance
degradation due to the domain gap and increase the robustness of the
segmentation model. Cross-dataset experiments and the ablation study are
conducted for the three different datasets: the Inria aerial image labeling
dataset, the Massachusetts building dataset, and the WHU East Asia dataset.
Compared to the performance of the segmentation network without the DATA
scheme, the proposed method shows improvements in the overall IoU. Moreover, it
is verified that the proposed method outperforms even when compared to feature
adaptation (FA) and output space adaptation (OSA).Comment: 11pages, 12 figure
Cathodic regeneration of a clean and ordered Cu(100)-(1×1) surface from an air-oxidized and disordered electrode: An operando STM study
In work related to the electrocatalysis of the CO_2 reduction reactions, we recently reported in This Journal the structure and composition of a Cu(100) electrode surface, pre-dosed at low levels of O_(2(g)) to simulate a Cu electrocatalyst unprotected from air, before and after immersion in alkaline electrolyte at fairly negative potentials to ascertain if an oxide-to-metal reduction reaction can be effected; experimental measurements were based upon ex situ techniques, low-energy electron diffraction (LEED) and Auger electron spectroscopy (AES). It was found that the mildly oxided surface remained ordered and could be cathodically reduced back to a well-ordered oxide-free Cu(100); the quality of the LEED pattern and AES spectrum was less than ideal, however, due to small amounts of base electrolyte remnant in the emersed layer. In this Short Communication, we present results from operando electrochemical scanning tunneling microscopy (EC-STM) that not only confirm the earlier observations but, more importantly, depict more accurately the actual electrocatalysis conditions. An as-received commercially oriented Cu(100) disk that had not been protected from air was observed to consist of narrow terraces encrusted with highly disordered oxides. Cyclic voltammetry and coulometry showed that the oxidized surface consisted of five monolayers of CuO and quarter of a monolayer of Cu_2O. Upon complete cathodic reduction of the interfacial oxides, the surface was found to have reverted to a single-crystalline Cu(100)-(1×1) structure. It may thus be inferred that, under the conditions of electrochemical CO_2 reduction, the Cu catalyst would exist as a zerovalent metal
Preroughening, Diffusion, and Growth of An FCC(111) Surface
Preroughening of close-packed fcc(111) surfaces, found in rare gas solids, is
an interesting, but poorly characterized phase transition. We introduce a
restricted solid-on-solid model, named FCSOS, which describes it. Using mostly
Monte Carlo, we study both statics, including critical behavior and scattering
properties, and dynamics, including surface diffusion and growth. In antiphase
scattering, it is shown that preroughening will generally show up at most as a
dip. Surface growth is predicted to be continuous at preroughening, where
surface self-diffusion should also drop. The physical mechanism leading to
preroughening on rare gas surfaces is analysed, and identified in the step-step
elastic repulsion.Comment: Revtex + uuencoded figures, to appear in Physical Review Letter
Morphology of travel routes and the organization of cities
This is the final version. Available from Nature Research via the DOI in this recordData availability.
All data needed to evaluate the conclusions are present in the paper and/or the Supplementary Materials. Additional data related to this paper may be requested from the authors and are also available at https://github.com/mlee96/inness_research.The city is a complex system that evolves through its inherent social and economic interactions. Mediating the movements of people and resources, urban street networks offer a spatial footprint of these activities. Of particular interest is the interplay between street structure and its functional usage. Here, we study the shape of 472,040 spatiotemporally optimized travel routes in the 92 most populated cities in the world, finding that their collective morphology exhibits a directional bias influenced by the attractive (or repulsive) forces resulting from congestion, accessibility, and travel demand. To capture this, we develop a simple geometric measure, inness, that maps this force field. In particular, cities with common inness patterns cluster together in groups that are correlated with their putative stage of urban development as measured by a series of socio-economic and infrastructural indicators, suggesting a strong connection between urban development, increasing physical connectivity, and diversity of road hierarchies.US Army Research OfficeNational Research Foundation of Korea funded by the Ministry of Science and ICTMinistry of Education of the Republic of Kore
Motion management within two respiratory-gating windows: feasibility study of dual quasi-breath-hold technique in gated medical procedures.
A dual quasi-breath-hold (DQBH) technique is proposed for respiratory motion management (a hybrid technique combining breathing-guidance with breath-hold task in the middle). The aim of this study is to test a hypothesis that the DQBH biofeedback system improves both the capability of motion management and delivery efficiency. Fifteen healthy human subjects were recruited for two respiratory motion measurements (free breathing and DQBH biofeedback breathing for 15 min). In this study, the DQBH biofeedback system utilized the abdominal position obtained using an real-time position management (RPM) system (Varian Medical Systems, Palo Alto, USA) to audio-visually guide a human subject for 4 s breath-hold at EOI and 90% EOE (EOE90%) to improve delivery efficiency. We investigated the residual respiratory motion and the delivery efficiency (duty-cycle) of abdominal displacement within the gating window. The improvement of the abdominal motion reproducibility was evaluated in terms of cycle-to-cycle displacement variability, respiratory period and baseline drift. The DQBH biofeedback system improved the abdominal motion management capability compared to that with free breathing. With a phase based gating (mean ± std: 55 ± 5%), the averaged root mean square error (RMSE) of the abdominal displacement in the dual-gating windows decreased from 2.26 mm of free breathing to 1.16 mm of DQBH biofeedback (p-value = 0.007). The averaged RMSE of abdominal displacement over the entire respiratory cycles reduced from 2.23 mm of free breathing to 1.39 mm of DQBH biofeedback breathing in the dual-gating windows (p-value = 0.028). The averaged baseline drift dropped from 0.9 mm min(-1) with free breathing to 0.09 mm min(-1) with DQBH biofeedback (p-value = 0.048). The averaged duty-cycle with an 1 mm width of displacement bound increased from 15% of free breathing to 26% of DQBH biofeedback (p-value = 0.003). The study demonstrated that the DQBH biofeedback system has the potential to significantly reduce the residual respiratory motion with the improved duty cycle during the respiratory gating procedure
Tracking the prelude of the electroreduction of carbon monoxide via its interaction with Cu(100): Studies by operando scanning tunneling microscopy and infrared spectroscopy
The first isolable intermediate in the electrochemical reduction of carbon dioxide is carbon monoxide. This species, or its hydrated form, formic acid, is also the primary end product from all but a handful of metallic electrodes; with the latter, hydrogen gas is generated, but it emanates from the reduction of water and not from CO₂. Only one electrode material, zerovalent copper, can spawn, in greater-than-trace quantities, a variety of species that are more highly reduced than CO. Hence, if the aim is to pursue a reaction trail of the reduction of CO₂ to products other than CO, it would be both logical and expedient to track the electrocatalytic reaction of CO itself. Heterogeneous electrocatalysis is a surface phenomenon; it transpires only when the reactant, CO in this case, chemisorbs on, or chemically interacts with, the Cu electrode surface. There is no electrocatalytic reaction if there is no CO adsorption. In ultrahigh vacuum, no CO resides on the Cu(100) surface at temperatures higher than 200 K. However, under electrochemical conditions, CO is chemisorbed on Cu at ambient temperatures at a given potential. We thus paired, in seriatim fashion, scanning tunneling microscopy (STM) and polarization-modulation IR reflection-absorption spectroscopy (PMIRS) to document the influence of applied potential on the coverage, the molecular orientation, and the adlattice structure of CO adsorbed on Cu(100) in alkaline solutions; the results are described in this paper
Azo-Dye-Functionalized Polycarbonate Membranes for Textile Dye and Nitrate Ion Removal
Challenges exist in the wastewater treatment of dyes produced by the world’s growing textiles industry. Common problems facing traditional wastewater treatments include low retention values and breaking the chemical bonds of some dye molecules, which in some cases can release byproducts that can be more harmful than the original dye. This research illustrates that track-etched polycarbonate filtration membranes with 100-nanometer diameter holes can be functionalized with azo dye direct red 80 at 1000 µM, creating a filter that can then be used to remove the entire negatively charged azo dye molecule for a 50 µM solution of the same dye, with a rejection value of 96.4 ± 1.4%, at a stable flow rate of 114 ± 5 µL/min post-functionalization. Post-functionalization, Na+ and NO3− ions had on average 17.9%, 26.0%, and 31.1% rejection for 750, 500, and 250 µM sodium nitrate solutions, respectively, at an average flow rate of 177 ± 5 µL/min. Post-functionalization, similar 50 µM azo dyes had increases in rejection from 26.3% to 53.2%. Rejection measurements were made using ultraviolet visible-light spectroscopy for dyes, and concentration meters using ion selective electrodes for Na+ and NO3− ions
The Price of Anarchy in Transportation Networks: Efficiency and Optimality Control
Uncoordinated individuals in human society pursuing their personally optimal
strategies do not always achieve the social optimum, the most beneficial state
to the society as a whole. Instead, strategies form Nash equilibria which are
often socially suboptimal. Society, therefore, has to pay a price of anarchy
for the lack of coordination among its members. Here we assess this price of
anarchy by analyzing the travel times in road networks of several major cities.
Our simulation shows that uncoordinated drivers possibly waste a considerable
amount of their travel time. Counterintuitively,simply blocking certain streets
can partially improve the traffic conditions. We analyze various complex
networks and discuss the possibility of similar paradoxes in physics.Comment: major revisions with multicommodity; Phys. Rev. Lett., accepte
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