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Deep Learning for Semantic Segmentation of 3D Ultrasound Data
Authors:
Chenyu Liu,
Marco Cecotti,
Harikrishnan Vijayakumar,
Patrick Robinson,
James Barson,
Mihai Caleap
Abstract:
Developing cost-efficient and reliable perception systems remains a central challenge for automated vehicles. LiDAR and camera-based systems dominate, yet they present trade-offs in cost, robustness and performance under adverse conditions. This work introduces a novel framework for learning-based 3D semantic segmentation using Calyo Pulse, a modular, solid-state 3D ultrasound sensor system for us…
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Developing cost-efficient and reliable perception systems remains a central challenge for automated vehicles. LiDAR and camera-based systems dominate, yet they present trade-offs in cost, robustness and performance under adverse conditions. This work introduces a novel framework for learning-based 3D semantic segmentation using Calyo Pulse, a modular, solid-state 3D ultrasound sensor system for use in harsh and cluttered environments. A 3D U-Net architecture is introduced and trained on the spatial ultrasound data for volumetric segmentation. Results demonstrate robust segmentation performance from Calyo Pulse sensors, with potential for further improvement through larger datasets, refined ground truth, and weighted loss functions. Importantly, this study highlights 3D ultrasound sensing as a promising complementary modality for reliable autonomy.
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Submitted 19 January, 2026;
originally announced January 2026.
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Neuroaesthetics and the Science of Visual Experience
Authors:
Harish Vijayakumar
Abstract:
Neuroaesthetics is an interdisciplinary field that brings together neuroscience, psychology, and the arts to explore how the human brain perceives and responds to visual beauty. This paper examines the neural mechanisms behind aesthetic experiences, aiming to explain why certain designs or artworks feel emotionally or cognitively "right." By analyzing the interaction between perception, emotion, a…
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Neuroaesthetics is an interdisciplinary field that brings together neuroscience, psychology, and the arts to explore how the human brain perceives and responds to visual beauty. This paper examines the neural mechanisms behind aesthetic experiences, aiming to explain why certain designs or artworks feel emotionally or cognitively "right." By analyzing the interaction between perception, emotion, and cognition, neuroaesthetics reveals how beauty is constructed in the brain and how this understanding can inform fields such as graphic and interface design. This paper offers a clear and accessible overview of core neuroaesthetic principles, making the subject approachable to a wide audience. The findings suggest that impactful design is more than surface-level appeal: well-crafted visual experiences can engage, support, and connect people in meaningful ways.
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Submitted 15 July, 2025;
originally announced July 2025.
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User Satisfaction -- UX Design Strategies for Seamless Virtual Experience
Authors:
Harish Vijayakumar
Abstract:
User Experience (UX) in virtual worlds is a fast-developing discipline that requires creative design concepts to overcome the divide between physical and virtual interaction. This research investigates primary principles and techniques to improve UX in virtual experiences based on usability, accessibility, user engagement, and technology advancements. It gives detailed insight into trends, issues,…
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User Experience (UX) in virtual worlds is a fast-developing discipline that requires creative design concepts to overcome the divide between physical and virtual interaction. This research investigates primary principles and techniques to improve UX in virtual experiences based on usability, accessibility, user engagement, and technology advancements. It gives detailed insight into trends, issues, and prospects for UX design of virtual applications that guarantee an efficient, easy-to-use, and immersive experience.
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Submitted 4 April, 2025;
originally announced April 2025.
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Static Detection of Filesystem Vulnerabilities in Android Systems
Authors:
Yu-Tsung Lee,
Hayawardh Vijayakumar,
Zhiyun Qian,
Trent Jaeger
Abstract:
Filesystem vulnerabilities persist as a significant threat to Android systems, despite various proposed defenses and testing techniques. The complexity of program behaviors and access control mechanisms in Android systems makes it challenging to effectively identify these vulnerabilities. In this paper, we present PathSentinel, which overcomes the limitations of previous techniques by combining st…
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Filesystem vulnerabilities persist as a significant threat to Android systems, despite various proposed defenses and testing techniques. The complexity of program behaviors and access control mechanisms in Android systems makes it challenging to effectively identify these vulnerabilities. In this paper, we present PathSentinel, which overcomes the limitations of previous techniques by combining static program analysis and access control policy analysis to detect three types of filesystem vulnerabilities: path traversals, hijacking vulnerabilities, and luring vulnerabilities. By unifying program and access control policy analysis, PathSentinel identifies attack surfaces accurately and prunes many impractical attacks to generate input payloads for vulnerability testing. To streamline vulnerability validation, PathSentinel leverages large language models (LLMs) to generate targeted exploit code based on the identified vulnerabilities and generated input payloads. The LLMs serve as a tool to reduce the engineering effort required for writing test applications, demonstrating the potential of combining static analysis with LLMs to enhance the efficiency of exploit generation and vulnerability validation. Evaluation on Android 12 and 14 systems from Samsung and OnePlus demonstrates PathSentinel's effectiveness, uncovering 51 previously unknown vulnerabilities among 217 apps with only 2 false positives. These results underscore the importance of combining program and access control policy analysis for accurate vulnerability detection and highlight the promising direction of integrating LLMs for automated exploit generation, providing a comprehensive approach to enhancing the security of Android systems against filesystem vulnerabilities.
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Submitted 15 July, 2024;
originally announced July 2024.
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PolyScope: Multi-Policy Access Control Analysis to Triage Android Scoped Storage
Authors:
Yu-Tsung Lee,
Haining Chen,
William Enck,
Hayawardh Vijayakumar,
Ninghui Li,
Zhiyun Qian,
Giuseppe Petracca,
Trent Jaeger
Abstract:
Android's filesystem access control is a crucial aspect of its system integrity. It utilizes a combination of mandatory access controls, such as SELinux, and discretionary access controls, like Unix permissions, along with specialized access controls such as Android permissions to safeguard OEM and Android services from third-party applications. However, when OEMs introduce differentiating feature…
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Android's filesystem access control is a crucial aspect of its system integrity. It utilizes a combination of mandatory access controls, such as SELinux, and discretionary access controls, like Unix permissions, along with specialized access controls such as Android permissions to safeguard OEM and Android services from third-party applications. However, when OEMs introduce differentiating features, they often create vulnerabilities due to their inability to properly reconfigure this complex policy combination. To address this, we introduce the POLYSCOPE tool, which triages Android filesystem access control policies to identify attack operations - authorized operations that may be exploited by adversaries to elevate their privileges. POLYSCOPE has three significant advantages over prior analyses: it allows for the independent extension and analysis of individual policy models, understands the flexibility untrusted parties have in modifying access control policies, and can identify attack operations that system configurations permit. We demonstrate the effectiveness of POLYSCOPE by examining the impact of Scoped Storage on Android, revealing that it reduces the number of attack operations possible on external storage resources by over 50%. However, because OEMs only partially adopt Scoped Storage, we also uncover two previously unknown vulnerabilities, demonstrating how POLYSCOPE can assess an ideal scenario where all apps comply with Scoped Storage, which can reduce the number of untrusted parties accessing attack operations by over 65% on OEM systems. POLYSCOPE thus helps Android OEMs evaluate complex access control policies to pinpoint the attack operations that require further examination.
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Submitted 27 February, 2023; v1 submitted 26 February, 2023;
originally announced February 2023.
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PolyScope: Multi-Policy Access Control Analysis to Triage Android Systems
Authors:
Yu-Tsung Lee,
William Enck,
Haining Chen,
Hayawardh Vijayakumar,
Ninghui Li,
Daimeng Wang,
Zhiyun Qian,
Giuseppe Petracca,
Trent Jaeger
Abstract:
Android filesystem access control provides a foundation for Android system integrity. Android utilizes a combination of mandatory (e.g., SEAndroid) and discretionary (e.g., UNIX permissions) access control, both to protect the Android platform from Android/OEM services and to protect Android/OEM services from third-party apps. However, OEMs often create vulnerabilities when they introduce market-d…
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Android filesystem access control provides a foundation for Android system integrity. Android utilizes a combination of mandatory (e.g., SEAndroid) and discretionary (e.g., UNIX permissions) access control, both to protect the Android platform from Android/OEM services and to protect Android/OEM services from third-party apps. However, OEMs often create vulnerabilities when they introduce market-differentiating features because they err when re-configuring this complex combination of Android policies. In this paper, we propose the PolyScope tool to triage the combination of Android filesystem access control policies to vet releases for vulnerabilities. The PolyScope approach leverages two main insights: (1) adversaries may exploit the coarse granularity of mandatory policies and the flexibility of discretionary policies to increase the permissions available to launch attacks, which we call permission expansion, and (2) system configurations may limit the ways adversaries may use their permissions to launch attacks, motivating computation of attack operations. We apply PolyScope to three Google and five OEM Android releases to compute the attack operations accurately to vet these releases for vulnerabilities, finding that permission expansion increases the permissions available to launch attacks, sometimes by more than 10X, but a significant fraction of these permissions (about 15-20%) are not convertible into attack operations. Using PolyScope, we find two previously unknown vulnerabilities, showing how PolyScope helps OEMs triage the complex combination of access control policies down to attack operations worthy of testing.
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Submitted 8 August, 2020;
originally announced August 2020.
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Understanding the Twitter Usage of Science Citation Index (SCI) Journals
Authors:
Aravind Sesagiri Raamkumar,
Mojisola Erdt,
Harsha Vijayakumar,
Aarthy Nagarajan,
Yin-Leng Theng
Abstract:
This paper investigates the Twitter interaction patterns of journals from the Science Citation Index (SCI) of Master Journal List (MJL). A total of 953,253 tweets extracted from 857 journal accounts, were analyzed in this study. Findings indicate that SCI journals interacted more with each other but much less with journals from other citation indices. The network structure of the communication gra…
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This paper investigates the Twitter interaction patterns of journals from the Science Citation Index (SCI) of Master Journal List (MJL). A total of 953,253 tweets extracted from 857 journal accounts, were analyzed in this study. Findings indicate that SCI journals interacted more with each other but much less with journals from other citation indices. The network structure of the communication graph resembled a tight crowd network, with Nature journals playing a major part. Information sources such as news portals and scientific organizations were mentioned more in tweets, than academic journal Twitter accounts. Journals with high journal impact factors (JIFs) were found to be prominent hubs in the communication graph. Differences were found between the Twitter usage of SCI journals with Humanities and Social Sciences (HSS) journals.
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Submitted 25 September, 2019;
originally announced September 2019.
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Understanding the Twitter Usage of Humanities and Social Sciences Academic Journals
Authors:
Aravind Sesagiri Raamkumar,
Mojisola Erdt,
Harsha Vijayakumar,
Edie Rasmussen,
Yin-Leng Theng
Abstract:
Scholarly communication has the scope to transcend the limitations of the physical world through social media extended coverage and shortened information paths. Accordingly, publishers have created profiles for their journals in Twitter to promote their publications and to initiate discussions with public. This paper investigates the Twitter presence of humanities and social sciences (HSS) journal…
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Scholarly communication has the scope to transcend the limitations of the physical world through social media extended coverage and shortened information paths. Accordingly, publishers have created profiles for their journals in Twitter to promote their publications and to initiate discussions with public. This paper investigates the Twitter presence of humanities and social sciences (HSS) journal titles obtained from mainstream citation indices, by analysing the interaction and communication patterns. This study utilizes webometric data collection, descriptive analysis, and social network analysis. Findings indicate that the presence of HSS journals in Twitter across disciplines is not yet substantial. Sharing of general websites appears to be the key activity performed by HSS journals in Twitter. Among them, web content from news portals and magazines are highly disseminated. Sharing of research articles and retweeting was not majorly observed. Inter-journal communication is apparent within the same citation index, but it is very minimal with journals from the other index. However, there seems to be an effort to broaden communication beyond the research community, reaching out to connect with the public.
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Submitted 15 July, 2018;
originally announced July 2018.
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Sprobes: Enforcing Kernel Code Integrity on the TrustZone Architecture
Authors:
Xinyang Ge,
Hayawardh Vijayakumar,
Trent Jaeger
Abstract:
Many smartphones now deploy conventional operating systems, so the rootkit attacks so prevalent on desktop and server systems are now a threat to smartphones. While researchers have advocated using virtualization to detect and prevent attacks on operating systems (e.g., VM introspection and trusted virtual domains), virtualization is not practical on smartphone systems due to the lack of virtualiz…
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Many smartphones now deploy conventional operating systems, so the rootkit attacks so prevalent on desktop and server systems are now a threat to smartphones. While researchers have advocated using virtualization to detect and prevent attacks on operating systems (e.g., VM introspection and trusted virtual domains), virtualization is not practical on smartphone systems due to the lack of virtualization support and/or the expense of virtualization. Current smartphone processors do have hardware support for running a protected environment, such as the ARM TrustZone extensions, but such hardware does not control the operating system operations sufficiently to enable VM introspection. In particular, a conventional operating system running with TrustZone still retains full control of memory management, which a rootkit can use to prevent traps on sensitive instructions or memory accesses necessary for effective introspection. In this paper, we present SPROBES, a novel primitive that enables introspection of operating systems running on ARM TrustZone hardware. Using SPROBES, an introspection mechanism protected by TrustZone can instrument individual operating system instructions of its choice, receiving an unforgeable trap whenever any SPROBE is executed. The key challenge in designing SPROBES is preventing the rootkit from removing them, but we identify a set of five invariants whose enforcement is sufficient to restrict rootkits to execute only approved, SPROBE-injected kernel code. We implemented a proof-of-concept version of SPROBES for the ARM Fast Models emulator, demonstrating that in Linux kernel 2.6.38, only 12 SPROBES are sufficient to enforce all five of these invariants. With SPROBES we show that it is possible to leverage the limited TrustZone extensions to limit conventional kernel execution to approved code comprehensively.
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Submitted 28 October, 2014;
originally announced October 2014.