827 research outputs found
SCADA System Testbed for Cybersecurity Research Using Machine Learning Approach
This paper presents the development of a Supervisory Control and Data
Acquisition (SCADA) system testbed used for cybersecurity research. The testbed
consists of a water storage tank's control system, which is a stage in the
process of water treatment and distribution. Sophisticated cyber-attacks were
conducted against the testbed. During the attacks, the network traffic was
captured, and features were extracted from the traffic to build a dataset for
training and testing different machine learning algorithms. Five traditional
machine learning algorithms were trained to detect the attacks: Random Forest,
Decision Tree, Logistic Regression, Naive Bayes and KNN. Then, the trained
machine learning models were built and deployed in the network, where new tests
were made using online network traffic. The performance obtained during the
training and testing of the machine learning models was compared to the
performance obtained during the online deployment of these models in the
network. The results show the efficiency of the machine learning models in
detecting the attacks in real time. The testbed provides a good understanding
of the effects and consequences of attacks on real SCADA environmentsComment: E-Preprin
Network Traffic Based Botnet Detection Using Machine Learning
The field of information and computer security is rapidly developing in today’s world as the number of security risks is continuously being explored every day. The moment a new software or a product is launched in the market, a new exploit or vulnerability is exposed and exploited by the attackers or malicious users for different motives. Many attacks are distributed in nature and carried out by botnets that cause widespread disruption of network activity by carrying out DDoS (Distributed Denial of Service) attacks, email spamming, click fraud, information and identity theft, virtual deceit and distributed resource usage for cryptocurrency mining. Botnet detection is still an active area of research as no single technique is available that can detect the entire ecosystem of a botnet like Neris, Rbot, and Virut. They tend to have different configurations and heavily armored by malware writers to evade detection systems by employing sophisticated evasion techniques. This report provides a detailed overview of a botnet and its characteristics and the existing work that is done in the domain of botnet detection. The study aims to evaluate the preprocessing techniques like variance thresholding and one-hot encoding to clean the botnet dataset and feature selection technique like filter, wrapper and embedded method to boost the machine learning model performance. This study addresses the dataset imbalance issues through techniques like undersampling, oversampling, ensemble learning and gradient boosting by using random forest, decision tree, AdaBoost and XGBoost. Lastly, the optimal model is then trained and tested on the dataset of different attacks to study its performance
DUET: Cross-modal Semantic Grounding for Contrastive Zero-shot Learning
Zero-shot learning (ZSL) aims to predict unseen classes whose samples have
never appeared during training. One of the most effective and widely used
semantic information for zero-shot image classification are attributes which
are annotations for class-level visual characteristics. However, the current
methods often fail to discriminate those subtle visual distinctions between
images due to not only the shortage of fine-grained annotations, but also the
attribute imbalance and co-occurrence. In this paper, we present a
transformer-based end-to-end ZSL method named DUET, which integrates latent
semantic knowledge from the pre-trained language models (PLMs) via a
self-supervised multi-modal learning paradigm. Specifically, we (1) developed a
cross-modal semantic grounding network to investigate the model's capability of
disentangling semantic attributes from the images; (2) applied an
attribute-level contrastive learning strategy to further enhance the model's
discrimination on fine-grained visual characteristics against the attribute
co-occurrence and imbalance; (3) proposed a multi-task learning policy for
considering multi-model objectives. We find that our DUET can achieve
state-of-the-art performance on three standard ZSL benchmarks and a knowledge
graph equipped ZSL benchmark. Its components are effective and its predictions
are interpretable.Comment: AAAI 2023 (Oral). Repository: https://github.com/zjukg/DUE
Spatio-Temporal Multimedia Big Data Analytics Using Deep Neural Networks
With the proliferation of online services and mobile technologies, the world has stepped into a multimedia big data era, where new opportunities and challenges appear with the high diversity multimedia data together with the huge amount of social data. Nowadays, multimedia data consisting of audio, text, image, and video has grown tremendously. With such an increase in the amount of multimedia data, the main question raised is how one can analyze this high volume and variety of data in an efficient and effective way. A vast amount of research work has been done in the multimedia area, targeting different aspects of big data analytics, such as the capture, storage, indexing, mining, and retrieval of multimedia big data. However, there is insufficient research that provides a comprehensive framework for multimedia big data analytics and management.
To address the major challenges in this area, a new framework is proposed based on deep neural networks for multimedia semantic concept detection with a focus on spatio-temporal information analysis and rare event detection. The proposed framework is able to discover the pattern and knowledge of multimedia data using both static deep data representation and temporal semantics. Specifically, it is designed to handle data with skewed distributions. The proposed framework includes the following components: (1) a synthetic data generation component based on simulation and adversarial networks for data augmentation and deep learning training, (2) an automatic sampling model to overcome the imbalanced data issue in multimedia data, (3) a deep representation learning model leveraging novel deep learning techniques to generate the most discriminative static features from multimedia data, (4) an automatic hyper-parameter learning component for faster training and convergence of the learning models, (5) a spatio-temporal deep learning model to analyze dynamic features from multimedia data, and finally (6) a multimodal deep learning fusion model to integrate different data modalities. The whole framework has been evaluated using various large-scale multimedia datasets that include the newly collected disaster-events video dataset and other public datasets
Cross-Modal Contrastive Learning for Robust Reasoning in VQA
Multi-modal reasoning in visual question answering (VQA) has witnessed rapid
progress recently. However, most reasoning models heavily rely on shortcuts
learned from training data, which prevents their usage in challenging
real-world scenarios. In this paper, we propose a simple but effective
cross-modal contrastive learning strategy to get rid of the shortcut reasoning
caused by imbalanced annotations and improve the overall performance. Different
from existing contrastive learning with complex negative categories on coarse
(Image, Question, Answer) triplet level, we leverage the correspondences
between the language and image modalities to perform finer-grained cross-modal
contrastive learning. We treat each Question-Answer (QA) pair as a whole, and
differentiate between images that conform with it and those against it. To
alleviate the issue of sampling bias, we further build connected graphs among
images. For each positive pair, we regard the images from different graphs as
negative samples and deduct the version of multi-positive contrastive learning.
To our best knowledge, it is the first paper that reveals a general contrastive
learning strategy without delicate hand-craft rules can contribute to robust
VQA reasoning. Experiments on several mainstream VQA datasets demonstrate our
superiority compared to the state of the arts. Code is available at
\url{https://github.com/qizhust/cmcl_vqa_pl}
Handling Concept Drift in the Context of Expensive Labels
Machine learning has been successfully applied to a wide range of prediction problems, yet its application to data streams can be complicated by concept drift. Existing approaches to handling concept drift are overwhelmingly reliant on the assumption that it is possible to obtain the true label of an instance shortly after classification at a negligible cost. The aim of this thesis is to examine, and attempt to address, some of the problems related to handling concept drift when the cost of obtaining labels is high. This thesis presents Decision Value Sampling (DVS), a novel concept drift handling approach which periodically chooses a small number of the most useful instances to label. The newly labelled instances are then used to re-train the classifier, an SVM with a linear kernel, to handle any change in concept that might occur. In this way, only the instances that are required to keep the classifier up-to-date are labelled. The evaluation of the system indicates that a classifier can be kept up-to-date with changes in concept while only requiring 15% of the data stream to be labelled. In a data stream with a high throughput this represents a significant reduction in the number of labels required.
The second novel concept drift handling approach proposed in this thesis is Confidence Distribution Batch Detection (CDBD). CDBD uses a heuristic based on the distribution of an SVM’s confidence in its predictions to decide when to rebuild the clas- sifier. The evaluation shows that CDBD can be used to reliably detect when a change in concept has taken place and that concept drift can be handled if the classifier is rebuilt when CDBD sig- nals a change in concept. The evaluation also shows that CDBD obtains a considerable labels saving as it only requires labelled data when a change in concept has been detected. The two concept drift handling approaches deal with concept drift in a different manner, DVS continuously adapts the clas- sifier, whereas CDBD only adapts the classifier when a sizeable change in concept is suspected. They reflect a divide also found in the literature, between continuous rebuild approaches (like DVS) and triggered rebuild approaches (like CDBD). The final major contribution in this thesis is a comparison between continuous and triggered rebuild approaches, as this is an underexplored area. An empirical comparison between representative techniques from both types of approaches shows that triggered rebuild works slightly better on large datasets where the changes in concepts occur infrequently, but in general a continuous rebuild approach works the best
Open-world Semi-supervised Generalized Relation Discovery Aligned in a Real-world Setting
Open-world Relation Extraction (OpenRE) has recently garnered significant
attention. However, existing approaches tend to oversimplify the problem by
assuming that all unlabeled texts belong to novel classes, thereby limiting the
practicality of these methods. We argue that the OpenRE setting should be more
aligned with the characteristics of real-world data. Specifically, we propose
two key improvements: (a) unlabeled data should encompass known and novel
classes, including hard-negative instances; and (b) the set of novel classes
should represent long-tail relation types. Furthermore, we observe that popular
relations such as titles and locations can often be implicitly inferred through
specific patterns, while long-tail relations tend to be explicitly expressed in
sentences. Motivated by these insights, we present a novel method called KNoRD
(Known and Novel Relation Discovery), which effectively classifies explicitly
and implicitly expressed relations from known and novel classes within
unlabeled data. Experimental evaluations on several Open-world RE benchmarks
demonstrate that KNoRD consistently outperforms other existing methods,
achieving significant performance gains.Comment: 10 pages, 6 figure
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