138 research outputs found
Experimental investigation on the bamboo-concrete filled circular steel tubular stub columns
[EN] Concrete-filled steel tubes have been widely used all over the world due to their superior structural behaviour. To promote the use of ecofriendly materials and to reduce the use of concrete, this paper presents an innovative type of composite column, which can be referred as bamboo-concrete filled steel tubes. In this kind of column, concrete filled in the space between the external steel tube and the inner raw moso bamboo. Bamboo-concrete filled steel tubes inherit the merits of concrete-filled steel tubes such as high load-bearing capacity and ductility performance. Besides, global buckling behaviour of a bamboo column due to its relatively large slenderness can be significantly improved, and the bamboo column with nodes could provide confinement to the infilled concrete. This paper investigated the composite effect of bamboo-concrete filled steel tubular stub columns subjected to axial compression. In addition, concrete-filled double-skin steel tubular stub columns and hollow concrete-filled steel tubular stub columns were also tested for comparison. The main experimental parameter considered was the diameter-to-thickness ratio (D/t) of steel tube. Test results indicated that the composite columns with moso bamboo pipe as inner core elements showed better ductility than the hollow concrete-filled steel tubular stub columns. The bearing capacity and ductility visibly increased with decreasing of the D/t ratio.Gan, D.; Zhang, T.; Zhou, X.; He, Z. (2018). Experimental investigation on the bamboo-concrete filled circular steel tubular stub columns. En Proceedings of the 12th International Conference on Advances in Steel-Concrete Composite Structures. ASCCS 2018. Editorial Universitat Politècnica de València. 385-391. https://doi.org/10.4995/ASCCS2018.2018.7138OCS38539
Efficient Query-Based Attack against ML-Based Android Malware Detection under Zero Knowledge Setting
The widespread adoption of the Android operating system has made malicious
Android applications an appealing target for attackers. Machine learning-based
(ML-based) Android malware detection (AMD) methods are crucial in addressing
this problem; however, their vulnerability to adversarial examples raises
concerns. Current attacks against ML-based AMD methods demonstrate remarkable
performance but rely on strong assumptions that may not be realistic in
real-world scenarios, e.g., the knowledge requirements about feature space,
model parameters, and training dataset. To address this limitation, we
introduce AdvDroidZero, an efficient query-based attack framework against
ML-based AMD methods that operates under the zero knowledge setting. Our
extensive evaluation shows that AdvDroidZero is effective against various
mainstream ML-based AMD methods, in particular, state-of-the-art such methods
and real-world antivirus solutions.Comment: To Appear in the ACM Conference on Computer and Communications
Security, November, 202
Comparison of physical and chemical properties of ambient aerosols during the 2009 haze and non-haze periods in Southeast Asia
Recurrent smoke-haze episodes that occur in Southeast Asia (SEA) are of much concern because of their environmental and health impacts. These haze episodes are mainly caused by uncontrolled biomass and peat burning in Indonesia. Airborne particulate matter (PM) samples were collected in the southwest coast of Singapore from 16 August to 9 November in 2009 to assess the impact of smoke-haze episodes on the air quality due to the long-range transport of biomass and peat burning emissions. The physical and chemical characteristics of PM were investigated during pre-haze, smoke-haze, and post-haze periods. Days with PM2.5 mass concentrations of ≥35 μg m−3 were considered as smoke-haze events. Using this criterion, out of the total 82 sampling days, nine smoke-haze events were identified. The origin of air masses during smoke-haze episodes was studied on the basis of HYSPLIT backward air trajectory analysis for 4 days. In terms of the physical properties of PM, higher particle surface area concentrations and particle gravimetric mass concentrations were observed during the smoke-haze period, but there was no consistent pattern for particle number concentrations during the haze period as compared to the non-haze period except that there was a significant increase at about 08:00, which could be attributed to the entrainment of PM from aloft after the breakdown of the nocturnal inversion layer. As for the chemical characteristics of PM, among the six key inorganic water-soluble ions (Cl−, NO3 −, nss-SO4 2−, Na+, NH4 +, and nss-K+) measured in this study, NO3 −, nss-SO4 2−, and NH4 + showed a significant increase in their concentrations during the smoke-haze period together with nss-K+. These observations suggest that the increased atmospheric loading of PM with higher surface area and increased concentrations of optically active secondary inorganic aerosols [(NH4)2SO4 or NH4HSO4 and NH4NO3] resulted in the atmospheric visibility reduction in SEA due to the advection of biomass and peat burning emissions
Static Semantics Reconstruction for Enhancing JavaScript-WebAssembly Multilingual Malware Detection
The emergence of WebAssembly allows attackers to hide the malicious
functionalities of JavaScript malware in cross-language interoperations, termed
JavaScript-WebAssembly multilingual malware (JWMM). However, existing
anti-virus solutions based on static program analysis are still limited to
monolingual code. As a result, their detection effectiveness decreases
significantly against JWMM. The detection of JWMM is challenging due to the
complex interoperations and semantic diversity between JavaScript and
WebAssembly. To bridge this gap, we present JWBinder, the first technique aimed
at enhancing the static detection of JWMM. JWBinder performs a
language-specific data-flow analysis to capture the cross-language
interoperations and then characterizes the functionalities of JWMM through a
unified high-level structure called Inter-language Program Dependency Graph.
The extensive evaluation on one of the most representative real-world
anti-virus platforms, VirusTotal, shows that \system effectively enhances
anti-virus systems from various vendors and increases the overall successful
detection rate against JWMM from 49.1\% to 86.2\%. Additionally, we assess the
side effects and runtime overhead of JWBinder, corroborating its practical
viability in real-world applications.Comment: Accepted to ESORICS 202
Structure Performance of Cold-formed Steel columns reinforced by Channel Sleeve under Axial and Eccentric compression
Due to the weak torsional stiffness of cold-formed thin-walled channel members, distortional buckling behavior maybe controlled the ultimate load-capacity under certain conditions. Therefore, a new section reinforced by Channel Sleeve is proposed in order to improve the structural capacity of channel columns in this paper and is performed on the axial and eccentric compression tests. The influence of Channel Sleeve spacing on the bearing capacity and failure mode is studied, and the beneficial effect of the Channel Sleeve on the bearing capacity is verified. First, the corresponding numerical modeling of the experiments is presented in detail by describing the numerical models, types of finite elements and methods of analyses. Second, the reinforced cold-formed steel members were subjected to axial and eccentric compression analysis. Next, the magnitude, direction of eccentricity and the sleeve position are varied, in order to address their effect on the columns' capacity and structural behavior. In addition, the numerical model is used to analyze the parameters such as the slenderness ratio of the specimen, the magnitude and direction of eccentricity. The influence of these parameter changes on the structural performance of the members under the action of axial and beam-column compression members is obtained. Finally, compare the bearing capacity of the axial compression specimen with the bearing capacity calculated by the North American Code
Let All be Whitened: Multi-teacher Distillation for Efficient Visual Retrieval
Visual retrieval aims to search for the most relevant visual items, e.g.,
images and videos, from a candidate gallery with a given query item. Accuracy
and efficiency are two competing objectives in retrieval tasks. Instead of
crafting a new method pursuing further improvement on accuracy, in this paper
we propose a multi-teacher distillation framework Whiten-MTD, which is able to
transfer knowledge from off-the-shelf pre-trained retrieval models to a
lightweight student model for efficient visual retrieval. Furthermore, we
discover that the similarities obtained by different retrieval models are
diversified and incommensurable, which makes it challenging to jointly distill
knowledge from multiple models. Therefore, we propose to whiten the output of
teacher models before fusion, which enables effective multi-teacher
distillation for retrieval models. Whiten-MTD is conceptually simple and
practically effective. Extensive experiments on two landmark image retrieval
datasets and one video retrieval dataset demonstrate the effectiveness of our
proposed method, and its good balance of retrieval performance and efficiency.
Our source code is released at https://github.com/Maryeon/whiten_mtd.Comment: Accepted by AAAI 202
A photo-triggered and photo-calibrated nitric oxide donor: rational design, spectral characterizations, and biological applications
Nitric oxide (NO) donors are valuable tools to probe the profound implications of NO in health and disease. The elusive nature of NO bio-relevance has largely limited the use of spontaneous NO donors and promoted the development of next generation NO donors, whose NO release is not only stimulated by a trigger, but also readily monitored via a judiciously built-in self-calibration mechanism. Light is without a doubt the most sensitive, versatile and biocompatible method of choice for both triggering and monitoring, for applications in complex biological matrices. Herein, we designed and synthesized an N-nitroso rhodamine derivative (NOD560) as a photo-triggered and photo-calibrated NO donor to address this need. NOD560 is essentially non-fluorescent. Upon irradiation by green light (532nm), it efficiently release NO and a rhodamine dye, the dramatic fluorescence turn-on from which could be harnessed to conveniently monitor the localization, flux, and dose of NO release. The potentials of NOD560 for in vitro biological applications were also exemplified in in vitro biological models, i.e. mesenchymal stem cell (MSC) migration suppression. NOD560 is expected to complement the existing NO donors and find widespread applications in chemical biological studies
Association analyses of East Asian individuals and trans-ancestry analyses with European individuals reveal new loci associated with cholesterol and triglyceride levels
Large-scale meta-analyses of genome-wide association studies (GWAS) have identified >175 loci associated with fasting cholesterol levels, including total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), and triglycerides (TG). With differences in linkage disequilibrium (LD) structure and allele frequencies between ancestry groups, studies in additional large samples may detect new associations. We conducted staged GWAS meta-analyses in up to 69,414 East Asian individuals from 24 studies with participants from Japan, the Philippines, Korea, China, Singapore, and Taiwan. These meta-analyses identified (P < 5 × 10-8) three novel loci associated with HDL-C near CD163-APOBEC1 (P = 7.4 × 10-9), NCOA2 (P = 1.6 × 10-8), and NID2-PTGDR (P = 4.2 × 10-8), and one novel locus associated with TG near WDR11-FGFR2 (P = 2.7 × 10-10). Conditional analyses identified a second signal near CD163-APOBEC1. We then combined results from the East Asian meta-analysis with association results from up to 187,365 European individuals from the Global Lipids Genetics Consortium in a trans-ancestry meta-analysis. This analysis identified (log10Bayes Factor ≥6.1) eight additional novel lipid loci. Among the twelve total loci identified, the index variants at eight loci have demonstrated at least nominal significance with other metabolic traits in prior studies, and two loci exhibited coincident eQTLs (P < 1 × 10-5) in subcutaneous adipose tissue for BPTF and PDGFC. Taken together, these analyses identified multiple novel lipid loci, providing new potential therapeutic targets
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