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arXiv 2024年

作者： Zou, Xiaotian Li, Ke Chen, Yongkang Faculty of Computer Science University of Exeter Exeter United Kingdom College of Electronic and Information Engineering Nanjing University of Aeronautics and Astronautics Nanjing China

Large Visual Language Models (VLMs) such as GPT-4V have achieved remarkable success in generating comprehensive and nuanced responses. Researchers have proposed various benchmarks for evaluating the capabilities of VLMs. With the integration of visual and text inputs in VLMs, new security issues emerge, as malicious attackers can exploit multiple modalities to achieve their objectives. This has led to increasing attention on the vulnerabilities of VLMs to jailbreak. Most existing research focuses on generating adversarial images or nonsensical image to jailbreak these models. However, no researchers evaluate whether logic understanding capabilities of VLMs in flowchart can influence jailbreak. Therefore, to fill this gap, this paper first introduces a novel dataset Flow-JD specifically designed to evaluate the logic-based flowchart jailbreak capabilities of VLMs. We conduct an extensive evaluation on GPT-4o, GPT-4V, other 5 SOTA open source VLMs and the jailbreak rate is up to 92.8%. Our research reveals significant vulnerabilities in current VLMs concerning image-to-text jailbreak and these findings underscore the the urgency for the development of robust and effective future defenses. Copyright © 2024, The Authors. All rights reserved.

关键词： Visual languages

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Game-Based Service Requests and Channel Selection in Mobile Edge Computing

Game-Based Service Requests and Channel Selection in Mobile ...

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International Conference on Communication Software and Networks, ICCSN

作者： Tong Yin Xin Chen Libo Jiao Hua Xing Geyong Min School of Computer Science Beijing Information Science & Technology University Beijing China College of Engineering Mathematics and Physical Sciences University of Exeter Exeter UK

Mobile edge computing (MEC) can provide service requests and resource allocation for user equipments (UEs), effectively reducing service delay for massive Internet-of-Things (IoT). Application providers cache services in the edge servers to reduce service requests delay. However, limited channel resources will affect transmission delay and communication quality when UEs request services from edge servers, thus reducing the user's Quality-of-Experience. In this paper, we investigate the service offloading problem between UEs and base stations (BSs), as well as between BSs and remote data centers (RDCs) in MEC systems with heterogeneous networks, considering channel selection between UEs and BSs. To minimize the service delay of each UE and thus improve user satisfaction, we propose game theory to model the problem as a non-cooperative game of channel selection and then demonstrate the existence of Nash equilibrium (NE). In order to find the ideal channel selection scheme, this paper proposes a best response based on a multi-user service request channel selection (SRCS) algorithm. Simulation results reveal that the proposed channel selection mechanism can improve user satisfaction and verify the effectiveness and convergence of the proposed algorithm.

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Priority-Aware Task Offloading and Resource Allocation in Satellite and HAP Assisted Edge-Cloud Collaborative Networks

Priority-Aware Task Offloading and Resource Allocation in Sa...

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International Conference on Communication Software and Networks, ICCSN

作者： Xin Dai Xin Chen Libo Jiao Yijie Wang Shougang Du Geyong Min School of Computer Science Beijing Information Science & Technology University Beijing China College of Engineering Mathematics and Physical Sciences University of Exeter Exeter UK

Mobile edge computing (MEC) has been regarded as an effective technique to handle computing intensive tasks of IoT devices (IoTDs). In this paper, we present a priority-aware edge computing model for space-air-ground integrated networks (SAGIN), which contain a satellite, a high altitude platform (HAP) and numerous IoTDs. In such networks, the HAP provides edge computing services close to the IoTDs and the cloud servers connected to satellite provide cloud computing services. The network considers different services for IoTDs with various Quality-of-Service (QoS) requirements. First, we design a media access control MAC protocol named priority-aware time division multiple access (PTDMA) for controlling the large-scale access of IoTDs. Second, for tasks with different priorities, we propose a priority-aware deep deterministic policy gradient (DDPG) based task offloading and resource allocation scheme (PDOA). Simulation experimental results validate the performance of the PTDMA and PDOA scheme, which can effectively improve the average system utility in a stochastic time-varying environment.

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Instrumental Variable methods to target Hypothetical Estimands with longitudinal repeated measures data: Application to the STEP 1 trial

arXiv

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arXiv 2024年

作者： Bowden, Jack Madsen, Jesper Goldman, Bryan Iversen, Aske Thorn Liang, Xiaoran Vansteelandt, Stijn Oxford United Kingdom Novo Nordisk Denmark Exeter Medical School University of Exeter Exeter United Kingdom Department of Applied Mathematics Computer Science and Statistics Ghent University Belgium

The STEP 1 randomized trial evaluated the effect of taking semaglutide vs placebo on body weight over a 68 week duration. As with any study evaluating an intervention delivered over a sustained period, non-adherence was observed. This was addressed in the original trial analysis within the Estimand Framework by viewing non-adherence as an intercurrent event. The primary analysis applied a treatment policy strategy which viewed it as an aspect of the treatment regimen, and thus made no adjustment for its presence. A supplementary analysis used a hypothetical strategy, targeting an estimand that would have been realised had all participants adhered, under the assumption that no post-baseline variables confounded adherence and change in body weight. In this paper we propose an alternative Instrumental Variable method to adjust for non-adherence which does not rely on the same 'unconfoundedness' assumption and is less vulnerable to positivity violations (e.g., it can give valid results even under conditions where non-adherence is guaranteed). Unlike many previous Instrumental Variable approaches, it makes full use of the repeatedly measured outcome data, and allows for a time-varying effect of treatment adherence on a participant's weight. We show that it provides a natural vehicle for defining two distinct hypothetical estimands: the treatment effect if all participants would have adhered to semaglutide, and the treatment effect if all participants would have adhered to both semaglutide and placebo. When applied to the STEP 1 study, they both suggest a sustained, slowly decaying weight loss effect of semaglutide treatment. © 2024, CC BY.

关键词： Automobile bodies

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Self-configuring high-speed multi-plane light conversion

arXiv

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arXiv 2025年

作者： Rocha, José C.A. Būtaitė, Unė G. Carpenter, Joel Phillips, David B. Physics and Astronomy University of Exeter ExeterEX4 4QL United Kingdom School of Electrical Engineering and Computer Science The University of Queensland BrisbaneQLD4072 Australia

Multi-plane light converters (MPLCs) – also known as linear diffractive neural networks – are an emerging optical technology, capable of converting an orthogonal set of optical fields into any other orthogonal set via a unitary transformation. MPLC design is a non-linear problem typically solved by optimising a digital model of the optical system. However, inherently high levels of design complexity mean that even a minor mismatch between this digital model and the physically realised MPLC leads to a severe reduction in real-world performance. Here we address this challenge by creating a self-configuring free-space MPLC. Despite the large number of parameters to be optimised (typically tens of thousands or more), our proof-of-principle device converges in minutes using a method in which light only needs to be transmitted in one direction through the MPLC. Two innovations make this possible. Firstly, we devise an in-situ optimisation algorithm combining wavefront shaping with the principles of wavefront matching that would conventionally be used to inverse-design MPLCs offline in simulation. Secondly, we introduce a new MPLC platform incorporating a microelectromechanical system (MEMS) phase-only light modulator – allowing rapid MPLC switching at up to kiloHertz rates. Our scheme automatically accounts for the physical characteristics of all system components and absorbs any unknown misalignments and aberrations into the final design. We demonstrate self-configured MPLCs capable of mapping random orthogonal speckle input fields to well-defined Laguerre-Gaussian and Hermite-Gaussian output modes, as well as universal mode sorters. Our work paves the way towards large-scale ultra-high-fidelity fast-switching MPLCs and diffractive neural networks, which promises to unlock new applications in areas ranging from optical communications to optical computing and imaging. Copyright © 2025, The Authors. All rights reserved.

关键词： Wavefronts

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Impulsive Control as a Novel Defibrillator Algorithm Using Coupled Van der Pol Oscillators

Impulsive Control as a Novel Defibrillator Algorithm Using C...

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International Conference on Data Analytics and Insights, ICDAI 2023

作者： Das, Saptarshi Maharatna, Koushik Centre for Environmental Mathematics University of Exeter Penryn Campus CornwallTR10 9FE United Kingdom Institute for Data Science and Artificial Intelligence University of Exeter North Park Road Devon ExeterEX4 4QE United Kingdom School of Electronics and Computer Science University of Southampton SouthamptonSO17 1BJ United Kingdom

ISBN: (纸本)9789819938773

This paper proposes a strategy for improving a patient-centric implantable cardioverter defibrillator (ICD) for real-time implementation, to deal with heart-related ailments like ventricular flutter and sinus bradycardia. A patient-centric dynamic model of heart rhythm is generated similar to the real Electrocardiogram (ECG) signals using three coupled Van der Pol (VdP) oscillators. These oscillators represent the dynamics of three nodes, viz. the Sino-Atrial (SA) node, Atrio-Ventricular (AV) node, and the His–Purkinje (HP) complex. The coupled VdP oscillator model-based closed-loop impulsive control methodology is then developed which starts functioning when there is aberrant behavior due to the diseased condition in the electrical activities generated by the different nodes of the heart. An embedded control system can be augmented to the ICD devices with the proposed control methodology having a patient-centric and disease-specific characteristic of the control law. The impulsive control strategy is specifically useful for such purposes over the continuous control techniques, as it helps in conserving the battery power of such devices and enables a longer lifetime of the ICD device. Numerical simulations are shown to illustrate the practicality of the proposed approach. © 2023, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.

关键词： Electrocardiograms

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Proactive video caching based on federated learning and implicit feedback in mobile edge computing

Proactive video caching based on federated learning and impl...

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IEEE Conference on Global Communications (GLOBECOM)

作者： Zhen Qian Guanghui Li Tao Qi Chenglong Dai Jia Hu School of Artificial Intelligence and Computer Science Jiangnan University Wuxi China Department of Computer Science University of Exeter UK

ISBN: (数字)9798350351255

ISBN: (纸本)9798350351262

The rapid development of 5G and the widespread use of smart terminal devices bring explosive video traffic growth. Edge caching technology in mobile edge computing systems stores popular content of most interest to users in advance in edge servers closer to mobile users to alleviate the pressure of traffic congestion and excessive access latency caused by centralized storage. However, how to obtain popular videos while protect user data privacy with only implicit user feedback data, such as liking, viewing, favoriting, etc., is the key challenge. To tackle these challenges, we proposed a proactive video caching scheme based on federated learning and implicit feedback (FIPC). First, a mobile edge-cloud system model contained a three-tier network architecture is developed. Then, we introduced the federated process for training the denoised auto-encoder model and video caching in detail. Finally, experimental results in Movielens dataset show that, without user data leakage, the proposed FIPC scheme outperforms the baseline caching algorithm using user feedback data.

关键词： Training Multi-access edge computing Federated learning Computational modeling Network architecture Data models Explosives Servers Global communication Traffic congestion

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On the Hyperparameter Loss Landscapes of Machine Learning Models: An Exploratory Study

arXiv

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arXiv 2023年

作者： Huang, Mingyu Li, Ke School of Computer Science and Engineering UESTC Chengdu China Department of Computer Science University of Exeter ExeterEX4 4QF United Kingdom

Previous efforts on hyperparameter optimization (HPO) of machine learning (ML) models predominately focus on algorithmic advances, yet little is known about the topography of the underlying hyperparameter (HP) loss landscape, which plays a fundamental role in governing the search process of HPO. While several works have conducted fitness landscape analysis (FLA) on various ML systems, they are limited to properties of isolated landscape without interrogating the potential structural similarities among them. The exploration of such similarities can provide a novel perspective for understanding the mechanism behind modern HPO methods, but has been missing, possibly due to the expensive cost of large-scale landscape construction, and the lack of effective analysis methods. In this paper, we mapped 1, 500 HP loss landscapes of 6 representative ML models on 63 datasets across different fidelity levels, with 11M+ configurations. By conducting exploratory analysis on these landscapes with fine-grained visualizations and dedicated FLA metrics, we observed a similar landscape topography across a wide range of models, datasets, and fidelities, and shed light on several central topics in HPO. Copyright © 2023, The Authors. All rights reserved.

关键词： Topography

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A PROGRESSIVE SCREENING APPROACH FOR MOORING CONFIGURATION SELECTION: A CASE STUDY OF THE ARVEN OFFSHORE WIND FARM 43

A PROGRESSIVE SCREENING APPROACH FOR MOORING CONFIGURATION S...

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ASME 2024 43rd International Conference on Ocean, Offshore and Arctic engineering, OMAE 2024

作者： Glasspool, Jonathan Tao, Longbin Venugopal, Vengatesan Pillai, Ajit C. School of Engineering The University of Edinburgh United Kingdom Department of Naval Architecture Ocean and Marine Engineering Faculty of Engineering University of Strathclyde United Kingdom Institute for Energy Systems School of Engineering The University of Edinburgh United Kingdom Renewable Energy Group Faculty of Environment Science and Economy University of Exeter United Kingdom

ISBN: (纸本)9780791887851

The mooring system of a floating offshore wind turbine (FOWT) impacts both the capital and operational expenses. The future success of floating offshore wind is, therefore, dependent on finding optimum mooring system designs from the wide field of possibilities. This paper introduces a methodology to identify appropriate mooring systems with the lowest cost using Arven Offshore Wind Farm as a case study. The methodology employs a systematic screening pipeline, utilizing short-duration time domain simulations in OrcaFlex to assess mooring line systems’ suitability based on DNV-ST-0437 and DNV-ST-0119 compliant load cases. Through progressively more detailed simulations, the pipeline efficiently narrows down the field of mooring configurations, assessing design parameters in one tenth of the time of a full enumeration. This approach allows for the identification of a lowest-cost mooring system, highlighting the design trade-offs between cost and key design parameters. For the Arven case study, the methodology has identified a semi-taut three-line nylon system with 225 m anchor radius, 1200 kN pretension and a 192 mm line diameter as being the most efficient system. The outlined methodology provides a broadly applicable and efficient means to identify optimum mooring systems for diverse development sites worldwide. Copyright © 2024 by ASME.

关键词： Mooring

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Towards Combating Frequency Simplicity-biased Learning for Domain Generalization 38

Towards Combating Frequency Simplicity-biased Learning for D...

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38th Conference on Neural Information Processing Systems, NeurIPS 2024

作者： He, Xilin Hu, Jingyu Lin, Qinliang Luo, Cheng Xie, Weicheng Song, Siyang Khan, Muhammad Haris Shen, Linlin Computer Vision Institute School of Computer Science & Software Engineering Shenzhen University China Shenzhen Institute of Artificial Intelligence and Robotics for Society China Guangdong Provincial Key Laboratory of Intelligent Information Processing China University of Exeter United Kingdom Mohamed bin Zayed University of Artificial Intelligence United Arab Emirates

Domain generalization methods aim to learn transferable knowledge from source domains that can generalize well to unseen target domains. Recent studies show that neural networks frequently suffer from a simplicity-biased learning behavior which leads to over-reliance on specific frequency sets, namely as frequency shortcuts, instead of semantic information, resulting in poor generalization performance. Despite previous data augmentation techniques successfully enhancing generalization performances, they intend to apply more frequency shortcuts, thereby causing hallucinations of generalization improvement. In this paper, we aim to prevent such learning behavior of applying frequency shortcuts from a data-driven perspective. Given the theoretical justification of models' biased learning behavior on different spatial frequency components, which is based on the dataset frequency properties, we argue that the learning behavior on various frequency components could be manipulated by changing the dataset statistical structure in the Fourier domain. Intuitively, as frequency shortcuts are hidden in the dominant and highly dependent frequencies of dataset structure, dynamically perturbating the over-reliance frequency components could prevent the application of frequency shortcuts. To this end, we propose two effective data augmentation modules designed to collaboratively and adaptively adjust the frequency characteristic of the dataset, aiming to dynamically influence the learning behavior of the model and ultimately serving as a strategy to mitigate shortcut learning. Code is available at AdvFrequency. © 2024 Neural information processing systems foundation. All rights reserved.

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