406 research outputs found
Reducing the Overhead of Memory Space, Network Communication and Disk I/O for Analytic Frameworks in Big Data Ecosystem
To facilitate big data processing, many distributed analytic frameworks and storage systems such as Apache Hadoop, Apache Hama, Apache Spark and Hadoop Distributed File System (HDFS) have been developed. Currently, many researchers are conducting research to either make them more scalable or enabling them to support more analysis applications. In my PhD study, I conducted three main works in this topic, which are minimizing the communication delay in Apache Hama, minimizing the memory space and computational overhead in HDFS and minimizing the disk I/O overhead for approximation applications in Hadoop ecosystem. Specifically, In Apache Hama, communication delay makes up a large percentage of the overall graph processing time. While most recent research has focused on reducing the number of network messages, we add a runtime communication and computation scheduler to overlap them as much as possible. As a result, communication delay can be mitigated. In HDFS, the block location table and its corresponding maintenance could occupy more than half of the memory space and 30% of processing capacity in master node, which severely limit the scalability and performance of master node. We propose Deister that uses deterministic mathematical calculations to eliminate the huge table for storing the block locations and its corresponding maintenance. My third work proposes to enable both efficient and accurate approximations on arbitrary sub-datasets of a large dataset. Existing offline sampling based approximation systems are not adaptive to dynamic query workloads and online sampling based approximation systems suffer from low I/O efficiency and poor estimation accuracy. Therefore, we develop a distribution aware method called Sapprox. Our idea is to collect the occurrences of a sub-dataset at each logical partition of a dataset (storage distribution) in the distributed system at a very small cost, and make good use of such information to facilitate online sampling
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
De-noising of Power Quality Disturbance Detection Based on Ensemble Empirical Mode Decomposition Threshold Algorithm
Actual power quality signal which is often affected by noise pollution impacts the analysis results of the disturbance signal. In this paper, EEMD (Ensemble Empirical Mode Decomposition)-based threshold de-noising method is proposed for power quality signal with different SNR (Signal-to-Noise Ratio). As a comparison, we use other four thresholds, namely, the heuristic threshold, the self-adaptive threshold, the fixed threshold and the minimax threshold to filter the noises from power quality signal. Through the analysis and comparison of three characteristics of the signal pre-and-post de-noised, including waveforms, SNR and MSE (Mean Square Error), furthermore the instantaneous attribute of corresponding time by HHT (Hilbert Huang Transform). Simulation results show that EEMD threshold de-noising method can make the waveform close to the actual value. The SNR is higher and the MSE is smaller compared with other four thresholds. The instantaneous attribute can reflect the actual disturbance signal more exactly. The optimal threshold EEMD-based algorithm is proposed for power quality disturbance signal de-noising. Meanwhile, EEMD threshold de-noising method with adaptivity is suitable for composite disturbance signal de-noising
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
Unveiling the roles of the glutathione redox system in vivo by analyzing genetically modified mice
Redox status affects various cellular activities, such as proliferation, differentiation, and death. Recent studies suggest pivotal roles of reactive oxygen species not only in pathogenesis under oxidative insult but also in intracellular signal transduction. Glutathione is present in several millimolar concentrations in the cytoplasm and has multiple roles in the regulation of cellular homeostasis. Two enzymes, γ-glutamylcysteine synthetase and glutathione synthetase, constitute the de novo synthesis machinery, while glutathione reductase is involved in the recycling of oxidized glutathione. Multidrug resistant proteins and some other transporters are responsible for exporting oxidized glutathione, glutathione conjugates, and S-nitrosoglutathione. In addition to antioxidation, glutathione is more positively involved in cellular activity via its sulfhydryl moiety of a molecule. Animals in which genes responsible for glutathione metabolism are genetically modified can be used as beneficial and reliable models to elucidate roles of glutathione in vivo. This review article overviews recent progress in works related to genetically modified rodents and advances in the elucidation of glutathione-mediated reactions
Pattern formation in oscillatory complex networks consisting of excitable nodes
Oscillatory dynamics of complex networks has recently attracted great
attention. In this paper we study pattern formation in oscillatory complex
networks consisting of excitable nodes. We find that there exist a few center
nodes and small skeletons for most oscillations. Complicated and seemingly
random oscillatory patterns can be viewed as well-organized target waves
propagating from center nodes along the shortest paths, and the shortest loops
passing through both the center nodes and their driver nodes play the role of
oscillation sources. Analyzing simple skeletons we are able to understand and
predict various essential properties of the oscillations and effectively
modulate the oscillations. These methods and results will give insights into
pattern formation in complex networks, and provide suggestive ideas for
studying and controlling oscillations in neural networks.Comment: 15 pages, 7 figures, to appear in Phys. Rev.
AdaCCD: Adaptive Semantic Contrasts Discovery based Cross Lingual Adaptation for Code Clone Detection
Code Clone Detection, which aims to retrieve functionally similar programs
from large code bases, has been attracting increasing attention. Modern
software often involves a diverse range of programming languages. However,
current code clone detection methods are generally limited to only a few
popular programming languages due to insufficient annotated data as well as
their own model design constraints. To address these issues, we present AdaCCD,
a novel cross-lingual adaptation method that can detect cloned codes in a new
language without any annotations in that language. AdaCCD leverages
language-agnostic code representations from pre-trained programming language
models and propose an Adaptively Refined Contrastive Learning framework to
transfer knowledge from resource-rich languages to resource-poor languages. We
evaluate the cross-lingual adaptation results of AdaCCD by constructing a
multilingual code clone detection benchmark consisting of 5 programming
languages. AdaCCD achieves significant improvements over other baselines, and
it is even comparable to supervised fine-tuning.Comment: 10 page
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
Facial Data Minimization: Shallow Model as Your Privacy Filter
Face recognition service has been used in many fields and brings much
convenience to people. However, once the user's facial data is transmitted to a
service provider, the user will lose control of his/her private data. In recent
years, there exist various security and privacy issues due to the leakage of
facial data. Although many privacy-preserving methods have been proposed, they
usually fail when they are not accessible to adversaries' strategies or
auxiliary data. Hence, in this paper, by fully considering two cases of
uploading facial images and facial features, which are very typical in face
recognition service systems, we proposed a data privacy minimization
transformation (PMT) method. This method can process the original facial data
based on the shallow model of authorized services to obtain the obfuscated
data. The obfuscated data can not only maintain satisfactory performance on
authorized models and restrict the performance on other unauthorized models but
also prevent original privacy data from leaking by AI methods and human visual
theft. Additionally, since a service provider may execute preprocessing
operations on the received data, we also propose an enhanced perturbation
method to improve the robustness of PMT. Besides, to authorize one facial image
to multiple service models simultaneously, a multiple restriction mechanism is
proposed to improve the scalability of PMT. Finally, we conduct extensive
experiments and evaluate the effectiveness of the proposed PMT in defending
against face reconstruction, data abuse, and face attribute estimation attacks.
These experimental results demonstrate that PMT performs well in preventing
facial data abuse and privacy leakage while maintaining face recognition
accuracy.Comment: 14 pages, 11 figure
- …