Fan Shi

Fan Shi


Research Focus & Metrics

Academic Career Length

7Years (2020-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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30 January 2025 in IEEE Transactions on Pattern Analysis and Machine Intelligence
Verified
Journal Article
Closed access
LLLi Liu
Li Liu
SSShuzhou Sun
Shuzhou Sun
SZShuaifeng Zhi
Shuaifeng Zhi
FSFan Shi
Fan Shi
ZLZhen Liu
Zhen Liu
YLYongxiang Liu
Yongxiang Liu
While recent debiasing methods for Scene Graph Generation (SGG) have shown impressive performance, these efforts often attribute model bias solely to the long-tail distribution of relationships, overlooking the more profound causes stemming from skewed object and object pair distributions. In this paper, we employ causal inference techniques to model the causality among these observed skewed distributions. Our insight lies in the ability of causal inference to capture the unobservable causal effects between complex distributions, which is crucial for tracing the roots of model bias. Specifically, we introduce the Mediator-based Causal Chain Model (MCCM), which, in addition to modeling causality among objects, object pairs, and relationships, incorporates mediator variables, i.e., cooccurrence distribution, for complementing the causality. Following this, we propose the Causal Adjustment Module (CAModule) to estimate the modeled causal structure, using variables from MCCM as inputs to produce a set of adjustment factors aimed at correcting biased model predictions. Moreover, our method enables the composition of zero-shot relationships, thereby enhancing the model’s ability to recognize such relationships. Experiments conducted across various SGG backbones and popular benchmarks demonstrate that CAModule achieves state-of-the-art mean recall rates, with significant improvements also observed on the challenging zero-shot recall rate metric.

10 August 2022 in Electronics
Verified
Journal Article
Open access
PDF file
CWChenyang Wang
Chenyang Wang
MZMin Zhang
Min Zhang
FSFan Shi
Fan Shi
PXPengfei Xue
Pengfei Xue
YLYang Li
Yang Li
With the development of network technology, the number of gambling websites has grown dramatically, causing a threat to social stability. There are many machine learning-based methods are proposed to identify gambling websites by analyzing the URL, the text, and the images of the websites. Nevertheless, most of the existing methods ignore one important piece of information, i.e., the text within the website images. Only the visual features of images are extracted for detection, while the semantic features of texts on the images are ignored. However, these texts have key information clearly pointing to gambling websites, which can help us identify such websites more accurately. Therefore, how to fuse image and text multimodal data is a challenge that should be met.Motivated by this, in this paper, we propose a hybrid multimodal data fusion-based method for identifying gambling websites by extracting and fusing visual and semantic features of the website screenshots. First, we fine tune the pretrained ResNet34 model to train an image classifier and to extract visual features of webpage screenshots. Second, we extract textual content from webpage screenshots through the optical character recognition (OCR) technique. We use pretrained Word2Vec word vectors as the initial embedding layer and use Bi-LSTM to train a text classifier and extract semantic features of textual content on the screenshots. Third, we use self-attention to fuse the visual and semantic features and train a multimodal classifier. The prediction results of image, text, and multimodal classifiers are fused by the late fusion method to obtain the final prediction result. To demonstrate the effectiveness of the proposed method, we conduct experiments on the webpage screenshot dataset we collected. The experimental results indicate that OCR text on the webpage screenshots has strong semantic features and the proposed hybrid multimodal data fusion based method can effectively improve the performance in identifying gambling websites, with accuracy, precision, recall, and F1-score all over 99%.

16 September 2024 in IEEE Transactions on Information Forensics and Security
Verified
Journal Article
Closed access
QLQianyu Li
Qianyu Li
RWRuipeng Wang
Ruipeng Wang
DLDong Li
Dong Li
FSFan Shi
Fan Shi
MZMin Zhang
Min Zhang
YLYang Li
Yang Li
Penetration testing, a crucial industrial practice for securing networked systems and infrastructures, has traditionally depended on the extensive expertise of human professionals. Addressing the scarcity of human experts, the development of automated penetration testing tools emerges as a promising avenue. Against the backdrop of rapid advancements in artificial intelligence technologies, reinforcement learning has demonstrated considerable potential for realizing automated penetration testing. However, existing research predominantly concentrates on reinforcement learning-based automated penetration testing tools within static scenarios, with limited exploration in dynamic network environments. This paper addresses a noteworthy challenge in developing autonomous agents for real-world applications, particularly focusing on scenarios marked by environmental changes. Such alterations necessitate autonomous agents to continuously monitor environmental characteristics, and adapt, and adjust learned actions to ensure the system’s effective operation. Consequently, the paper proposes an automated reinforcement learning-based penetration testing scheme tailored for dynamic network scenarios, named DynPen. DynPen captures observed changes in the scenario, aiding the penetration testing agent in decision-making based on historical experiences. Simulation results demonstrate the proposed scheme’s efficacy in significantly expediting the convergence speed of the penetration testing agent using reinforcement learning algorithms. Furthermore, the scheme successfully maintains the learning agility and adaptability of the agent in dynamic network scenarios.

18 October 2021 in Applied Sciences
Verified
Journal Article
Open access
PDF file
BGBingyang Guo
Bingyang Guo
YZYunyi Zhang
Yunyi Zhang
CXChengxi Xu
Chengxi Xu
FSFan Shi
Fan Shi
YLYuwei Li
Yuwei Li
MZMin Zhang
Min Zhang
Internet users have suffered from phishing attacks for a long time. Attackers deceive users through malicious constructed phishing websites to steal sensitive information, such as bank account numbers, website usernames, and passwords. In recent years, many phishing detection solutions have been proposed, which mainly leverage whitelists or blacklists, website content, or side channel-based techniques. However, with the continuous improvement of phishing technology, current methods have difficulty in achieving effective detection. Hence, in this paper, we propose an effective phishing website detection approach, which we call HinPhish. HinPhish extracts various link relationships from webpages and uses domains and resource objects to construct a heterogeneous information network. HinPhish applies a modified algorithm to leverage the characteristics of different link types in order to calculate the phish-score of the target domain on the webpage. Moreover, HinPhish not only improves the accuracy of detection, but also can increase the phishing cost for attackers. Extensive experimental results demonstrate that HinPhish can achieve an accuracy of 0.9856 and F1-score of 0.9858.

7 September 2022 in Applied Sciences
Verified
Journal Article
Open access
PDF file
FSFan Shi
Fan Shi
SKshaofeng kai
shaofeng kai
JZJinghua Zheng
Jinghua Zheng
YZYao Zhong
Yao Zhong
A plethora of software vulnerabilities are exposed daily, posing a severe threat to the Internet. It is almost impossible for security experts or software developers to deal with all vulnerabilities. Therefore, it is imperative to rapidly assess the severity of the vulnerability to be able to select which one should be given preferential attention. CVSS is now the industry’s de facto evaluation standard, which is calculated with a quantitative formula to measure the severity of a vulnerability. The CVSS formula consists of several metrics related to the vulnerability’s features. Security experts need to determine the values of each metric, which is tedious and time-consuming, therefore hindering the efficiency of severity assessment. To address this problem, in this paper, we propose a method based on a pre-trained model for the prediction of CVSS metric values. More specifically, this method utilizes the XLNet model that is fine-tuned with a self-built corpus to predict the metric values from the vulnerability description text, thus reducing the burden of the assessment procedure. To verify the performance of our method, we compare the XLNet model with other pre-trained models and conventional machine learning techniques. The experimental results show that the method outperforms these models on evaluation metrics, reaching state-of-the-art performance levels.

6 May 2023 in Applied Sciences
Verified
Journal Article
Open access
PDF file
CXChengxi Xu
Chengxi Xu
YZYunyi Zhang
Yunyi Zhang
FSFan Shi
Fan Shi
HSHong Shan
Hong Shan
BGBingyang Guo
Bingyang Guo
PXPengfei Xue
Pengfei Xue
The centralization of the global DNS ecosystem may accelerate the creation of an oligopoly market, thereby, increasing the risk of a single point of failure and network traffic manipulation. Earlier studies have revealed the level of centralization in terms of the market share of public DNS services and DNS traffic seen by major CDN providers. However, the level of centralization in the infrastructure of the DNS Ecosystem is not well understood. In this paper, we present a novel and lightweight measurement approach that effectively discovers resolver pools from a single probing point. We conduct an Internet-wide active measurement on the client-side as well as the server-side DNS infrastructure to assess the level of DNS centralization in terms of the supporting infrastructure. Our measurement results show that the DNS infrastructure is much more centralized than previously believed. Over 90% of forwarding resolvers are backed by less than 5% (4071) of indirect resolvers. Merely 0.45% (12,679) of all name servers across 1138 gTLDs, operated by just 10 DNS providers, provide authoritative domain resolution service for 48.5% (more than 100 million) of domain names. We also investigated several leading DNS providers in IP infrastructure, load distribution, and service geo-distribution. The findings of our measurements provide novel insights into the centrality of the DNS infrastructure, which will help the Internet community promote the understanding of the DNS ecosystem.