The success of image perturbations that are designed to fool image classifier is assessed in terms of both adversarial effect and visual imperceptibility. The conventional assumption on ...imperceptibility is that perturbations should strive for tight Lp-norm bounds in RGB space. In this work, we drop this assumption by pursuing an approach that exploits human color perception, and more specifically, minimizing perturbation size with respect to perceptual color distance. Our first approach, Perceptual Color distance C&W (PerC-C&W), extends the widely-used C&W approach and produces larger RGB perturbations. PerC-C&W is able to maintain adversarial strength, while contributing to imperceptibility. Our second approach, Perceptual Color distance Alternating Loss (PerC-AL), achieves the same outcome, but does so more efficiently by alternating between the classification loss and perceptual color difference when updating perturbations. Experimental evaluation shows PerC approaches outperform conventional Lp approaches in terms of robustness and transferability, and also demonstrates that the PerC distance can provide added value on top of existing structure-based methods to creating image perturbations.
Deep Neural Networks have been shown to be vulnerable to adversarial images. Conventional attacks strive for indistinguishable adversarial images with strictly restricted perturbations. Recently, ...researchers have moved to explore distinguishable yet non-suspicious adversarial images and demonstrated that color transformation attacks are effective. In this work, we propose Adversarial Color Filter (AdvCF), a novel color transformation attack that is optimized with gradient information in the parameter space of a simple color filter. In particular, our color filter space is explicitly specified so that we are able to provide a systematic analysis of model robustness against adversarial color transformations, from both the attack and defense perspectives. In contrast, existing color transformation attacks do not offer the opportunity for systematic analysis due to the lack of such an explicit space. We further demonstrate the effectiveness of our AdvCF in fooling image classifiers and also compare it with other color transformation attacks regarding their robustness to defenses and image acceptability through an extensive user study. We also highlight the human-interpretability of AdvCF and show its superiority over the state-of-the-art human-interpretable color transformation attack on both image acceptability and efficiency. Additional results provide interesting new insights into model robustness against AdvCF in another three visual tasks.
To solve the problems of high magnesium nickel slag (HMNS) and tailing stacks with large storage and environmental pollution, alkali-activated HMNS-based cementitious materials were prepared by using ...NaOH, phosphogypsum (PG), HMNS and ground granulated blast furnace slag (GGBFS), and cemented tailings backfill (CTB) was prepared using tailings as aggregates. The workability, strength characteristics, localized deformation and hydration mechanism of CTB were studied. Based on the digital speckle correlation method (DSCM), the localized deformation of CTB was analyzed. The hydration mechanism of CTB was analyzed by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), thermogravimetry-differential scanning calorimetry (TGDSC), mercury intrusion porosimetry (MIP) and scanning electron microscopy and energy dispersive spectroscopy (SEMEDS). The results showed that the optimal mix proportions for the cementitious material were 8%, 30%, 6%, and 0.38 for PG content, GGBFS content, alkali dosage, and water/binder ratio, respectively. The best performance of CTB was achieved when the bone glue ratio (BGR) and mass concentration (MC) were 5:1 and 79%, respectively; the slump, slump flow, and consistency of CTB decreased continuously with increasing BGR and MC; the layering degree, bleeding rate, and linear shrinkage of CTB continuously increased with increasing BGR, and decreased with increasing MC; the unconfined compressive strength of CTB increased with increasing maintenance age and MC and decreased with increasing BGR; when the BGR was small (3:1), CTB exhibited shear failure, and when the BGR was large (6:1), CTB exhibited tensile failure. The main hydration products of CTB were C-S-H gel, M-S-H gel, ettringite (AFt), Ca(OH)2 and CaCO3. In the early stage of curing, CTB has more pores, fewer hydration products and a relatively loose internal structure, flocculation, sheet, network and needle rod hydration products coated tailing particles, porosity decreased, and CTB became dense.
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•A new type of alkali-activated cementitious material has been prepared.•A new type of cemented tailings backfill (CTB) was prepared.•The workability and strength characteristics of CTB were studied.•The localized deformation of CTB was analyzed based on DSCM.•The hydration mechanism of CTB was analyzed by microscopic test.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
•The LCOEs of offshore wind power in China are calculated.•The learning rate of offshore wind power is estimated using learning curve method.•The grid parity of offshore wind power in China’s five ...provinces is assessed.•Grid parity can be achieved earlier with carbon finance policy being introduced.
Achieving grid parity of offshore wind power in China has great implication for the future energy system transition and plays an important role in achieving its carbon-peaking and carbon–neutral targets. However, the pace to reach grid parity among different regions as well as the policy needed to achieve it may be different in view of the disparity in the resource endowment and economic and market conditions. In this work, we collect the data of 83 offshore wind power projects connected to the grid in the period of 2013–2020 in China, and we estimate the learning rates of offshore wind power technology using learning curve model. Then, the future LCOEs of offshore wind power are projected among different provinces. Further, by comparing the future LCOEs and the on-grid price of coal-fired power, whether and when, and under what conditions the grid parity can be achieved are assessed at the province level, and especially the carbon finance policy needed to achieve the grid parity is explored. Finally, the policy strategy aimed to achieve grid parity among different regions is proposed.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Evaluating the frequency-dependent resistivity and permittivity of deep soil is necessary for accurately analyzing the transient performance of grounding device. In this paper the skin effect of soil ...and the effect of the current measurement lead of Wenner's method on the current distribution in the soil at different frequency are investigated by numerical simulation, with which the applicability of Wenner's method for measuring the frequency-dependent resistivity and permittivity of deep soil is analyzed. The results show that the Wenner's method can definitely be used only at frequencies below 500 Hz for <inline-formula> <tex-math notation="LaTeX">100~{\Omega }\text{m} </tex-math></inline-formula> soil, because at higher frequency most of the current collects in the topsoil due to the skin effect and the induction of the current measurement lead on the current distribution in the soil. The higher the resistivity, or the shorter the distance between the current poles, the higher the applicable frequency.
Biliary tract cancer (BTC) is an invasive adenocarcinoma affecting the hepatobiliary system, but high recurrence rates highlight the need for more effective adjuvant approaches. The modified Glasgow ...prognostic score (mGPS) has been explored as an independent prognostic indicator in patients with BTC. However, consensus on its prognostic value is lacking. This meta-analysis aimed to comprehensively assess the association between mGPS and diverse clinical outcomes in BTC by systematically analyzing relevant studies.
A systematic search approach was used to look for eligible papers published until June 2023 in PubMed, Web of Science, and Embase, with a focus on overall survival (OS) and disease-free/recurrence-free survival (DFS/RFS). The prognostic potential of mGPS was assessed using hazard ratios (HRs) with corresponding 95% CIs.
A total of 15 papers comprising 2447 patients were included in this meta-analysis. The results demonstrated that, in patients with BTC, the high mGPS was associated with poorer OS (HR=1.49, 95% CI=1.35-1.65, P<0.001) and DFS/RFS (HR=3.23, 95%CI=1.98-5.26, P=0.193).
According to this meta-analysis, our study found that high mGPS was associated with poorer OS and DFS/RFS in patients with BTC.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
In this paper, a 3-dimensional method of characteristics is used to calculate the ion flow field around a metal building in the vicinity of bipolar HVDC transmission lines. The surface charges are ...introduced to make sure that the surface of the metal building is equipotential. An improved iterative method is proposed to solve the ion flow field. A reduced-scale test under laboratory conditions is carried out to verify the calculation results. Comparison of the results with those by Deutsch Assumption shows that although the two groups of results on the ground are in good agreement, the electric fields in space are different because the method of characteristics considers the effect of space charges on the direction of the electric field. The ion flow field around a metal building in the vicinity of a 800 kV transmission line was calculated with the method and discussed.
Operation of SF 6 gas-insulated switchgear (GIS) produces very fast transient overvoltage, which may interfere with the secondary system through many paths. As more and more smart devices are placed ...near GIS, their anti-EMI capability becomes more and more important. In response to the above problems, this paper carried out on-site measurement on the EMI in the secondary system during the operation of a 500 kV GIS. The EMI in the cable connecting the cabinet near the GIS and the control center 60 m away was paid attention to. By simultaneously measuring the electric field in space, the current through the grounding lead of the GIS, the EMI in the cables with different grounding methods, and the transient ground potential difference between the cabinet and the control center, the effects of different interference paths such as the spatial electromagnetic coupling and grounding system were analyzed. Results show that, the GIS operation will not only generate a spatial electric field, but also induce a circulating current on its grounding leads, resulting in an apparent ground potential difference on the grounding grid. When the shielding of the cable is grounded at both ends, the EMI is mainly determined by the spatial electric field and current in the shielding. As for the cable with single end grounded, the core-shielding voltage contains stronger high frequency components than that when the cable is grounded with both ends. The ground potential difference is the main source of core-ground voltage below 3 MHz when the cable is grounded at single end. Above 3 MHz the space electric field is the main source.
Considering that the existing video saliency prediction methods still have limitations in spatiotemporal correlation learning between features and saliency regions, this paper proposes a ...spatiotemporal module for video saliency prediction based on self-attention. The proposed model emphasizes three essential problems as follows. First, we raise a multi-scale feature-fusion network (MFN) for effective feature integration. The framework can extract and fuse features from four scales at low memory cost. Second, we view the task as a global evaluation of the correlation on pixel level to predict human visual attention in task-driven scenes more accurately. An adapted transformer encoder is designed for spatiotemporal correlation learning. Finally, we introduce DConvLSTM to learn the context in videos. Experimental results show that the proposed model achieves state-of-the-art performance on both driving scenes and natural scenes with multi-motion information. And our model also achieves very comparable performance especially in natural scenes with multi-category objects. It proves our method is practicable in both data-driven and task-driven conditions.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Charges resulting from corona on dc transmission lines will be driven by the electric field to the space and form the ion flow field. Some space charges will accumulate on the surface of the ...insulated buildings in the vicinity of high-voltage direct current transmission lines and may lead to human body shock. An improved iterative method is used to solve the ion flow field and accumulated charges according to the boundary condition that the normal component of electric field on the insulated building surface is zero. The accumulated charges are calculated by a 3-D method of characteristics based on the known ion flow field, which avoids large-scale numerical calculation. The calculation results are in a good agreement with the measured data of reduced-scale test under laboratory conditions.
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