arXiv subjects

Man-Ki Yoon

Publications and source records attributed to Man-Ki Yoon.

9 recordsLinked to original sources

arXiv2026

DejaVu: Unifying Memory Allocations to Eliminate Redundant Copies on Unified-Memory SoCs

GPU applications on unified-memory (UMA) edge platforms often inherit a discrete-GPU memory abstraction in which they allocate one buffer for the CPU, another for the GPU, and copy data between them before and after GPU execution. On UMA hardware these buffers reside in the same physical DRAM, so the copies consume bandwidth, time, and energy without moving data across a physical boundary. Despite the growing adoption of UMA platforms, this pattern remains common because production software stacks, libraries, and samples were written for portability across discrete GPUs. However, removing these copies is not as simple as merging the two buffers, because the original program may rely on the two buffers being distinct, or on the copy itself ordering CPU and GPU accesses. DejaVu removes these copies only when the program does not depend on the effects above. It does so along two complementary paths, depending on whether source is available. DejaVu-SR is a compile-time LLVM transformation that proves safety and rewrites accepted pairs in place. DejaVu-DR is a profile-guided binary optimizer for closed-source deployments that profiles and validates stable allocation/copy patterns and, at runtime, intercepts the matching calls to coalesce profile-matched pairs while preserving the ordering effects of removed copies. Across seven benchmarks on three NVIDIA Jetson platforms, DejaVu's benefit grows with the fraction of baseline time spent on copies. Copy-dominated workloads speed up by up to 6.9$\times$, closed-source end-to-end applications speed up by 1.10-1.14$\times$. Both source and binary paths achieve $\ge$99% of the performance achievable by manual optimization.

cs.DC↗

arXiv2026

AdaptAV: Continuous Adaption of Vision Models for Autonomous Vehicles Using Cloud-based Oracle

Deploying vision perception models in autonomous vehicles requires that we prioritize inference speeds, resulting in a model with shallower architectures and lesser model parameters (i.e., more pruned). Such small models do not generalize well, which could result in poor performance when encountered with novel scenarios. We propose a system that overcomes this by continuously retraining the vision models on the cloud with data uploaded by vehicles. We leverage the abundant compute resources, including machine learning accelerators, of the cloud to run a highly-accurate oracle model that will guide the retraining process of the on-vehicle model. This newly trained model is transmitted to the vehicle over the network and is utilized by the vehicle for perceptions, leading to improved inference accuracy over time.

cs.CV↗

arXiv2026

FrameScope: Temporal Data Valuation for Stream Active Learning in Autonomous Vehicle Systems

Autonomous vehicles operate in dynamic, ever-changing environments where new scenarios and edge cases constantly emerge. As a result, static learning models are inadequate for ensuring safe and reliable operation. Continuous learning is essential for adapting to these evolving conditions and maintaining robust performance across diverse real-world settings. However, autonomous vehicles generate massive streams of visual data during operation, and existing continuous learning approaches typically rely on heuristic sampling methods that fail to capture temporal dynamics, often overlooking critical learning opportunities or selecting redundant frames. In this paper, we introduce FrameScope, a temporal data valuation framework for continuous learning in autonomous vehicles. FrameScope extends neural tangent kernel theory to temporal domains, enabling principled valuation of streaming visual data. Unlike cloud-centric methods that transmit all video data for processing, our approach performs principled, local frame selection on the vehicle and queries a cloud-based oracle model only for labels of those high-value frames. Extensive experiments across multiple domain shifts show that FrameScope consistently outperforms existing methods, achieving higher sample efficiency and significantly reducing catastrophic forgetting in autonomous vehicle perception. By valuing data on the vehicle and querying only labels for selected frames, FrameScope reduces bandwidth requirements, enabling scalable operation with a lightweight cloud labeling service.

cs.CV↗

arXiv2026

Ringmaster: How to juggle high-throughput host OS system calls from TrustZone TEEs

Many safety-critical systems require timely processing of sensor inputs to avoid potential safety hazards. Additionally, to support useful application features, such systems increasingly have a large rich operating system (OS) at the cost of potential security bugs. Thus, if a malicious party gains supervisor privileges, they could cause real-world damage by denying service to time-sensitive programs. Many past approaches to this problem completely isolate time-sensitive programs with a hypervisor; however, this prevents the programs from accessing useful OS services. We introduce Ringmaster, a novel framework that enables enclaves or TEEs (Trusted Execution Environments) to asynchronously access rich, but potentially untrusted, OS services via Linux's io_uring. When service is denied by the untrusted OS, enclaves continue to operate on Ringmaster's minimal ARM TrustZone kernel with access to small, critical device drivers. This approach balances the need for secure, time-sensitive processing with the convenience of rich OS services. Additionally, Ringmaster supports large unmodified programs as enclaves, offering lower overhead compared to existing systems. We demonstrate how Ringmaster helps us build a working highly-secure system with minimal engineering. In our experiments with an unmanned aerial vehicle, Ringmaster achieved nearly 1GiB/sec of data into enclave on a Raspberry Pi4b, 0-3% throughput overhead compared to non-enclave tasks.

cs.CR↗

arXiv2019

TaskShuffler++: Real-Time Schedule Randomization for Reducing Worst-Case Vulnerability to Timing Inference Attacks

This paper presents a schedule randomization algorithm that reduces the vulnerability of real-time systems to timing inference attacks which attempt to learn the timing of task execution. It utilizes run-time information readily available at each scheduling decision point to increase the level of uncertainty in task schedules, while preserving the original schedulability. The randomization algorithm significantly reduces an adversary's best chance to correctly predict what tasks would run at arbitrary times. This paper also proposes an information-theoretic measure that can quantify the worst-case vulnerability, from the defender's perspective, of an arbitrary real-time schedule.

cs.CR↗

arXiv2019

Novelty Detection via Network Saliency in Visual-based Deep Learning

Machine-learning driven safety-critical autonomous systems, such as self-driving cars, must be able to detect situations where its trained model is not able to make a trustworthy prediction. Often viewed as a black-box, it is non-obvious to determine when a model will make a safe decision and when it will make an erroneous, perhaps life-threatening one. Prior work on novelty detection deal with highly structured data and do not translate well to dynamic, real-world situations. This paper proposes a multi-step framework for the detection of novel scenarios in vision-based autonomous systems by leveraging information learned by the trained prediction model and a new image similarity metric. We demonstrate the efficacy of this method through experiments on a real-world driving dataset as well as on our in-house indoor racing environment.

cs.LG↗

arXiv2018

Grouped Convolutional Neural Networks for Multivariate Time Series

Analyzing multivariate time series data is important for many applications such as automated control, fault diagnosis and anomaly detection. One of the key challenges is to learn latent features automatically from dynamically changing multivariate input. In visual recognition tasks, convolutional neural networks (CNNs) have been successful to learn generalized feature extractors with shared parameters over the spatial domain. However, when high-dimensional multivariate time series is given, designing an appropriate CNN model structure becomes challenging because the kernels may need to be extended through the full dimension of the input volume. To address this issue, we present two structure learning algorithms for deep CNN models. Our algorithms exploit the covariance structure over multiple time series to partition input volume into groups. The first algorithm learns the group CNN structures explicitly by clustering individual input sequences. The second algorithm learns the group CNN structures implicitly from the error backpropagation. In experiments with two real-world datasets, we demonstrate that our group CNNs outperform existing CNN based regression methods.

cs.LG↗

arXiv2017

A Reconnaissance Attack Mechanism for Fixed-Priority Real-Time Systems

In real-time embedded systems (RTS), failures due to security breaches can cause serious damage to the system, the environment and/or injury to humans. Therefore, it is very important to understand the potential threats and attacks against these systems. In this paper we present a novel reconnaissance attack that extracts the exact schedule of real-time systems designed using fixed priority scheduling algorithms. The attack is demonstrated on both a real hardware platform and a simulator, with a high success rate. Our evaluation results show that the algorithm is robust even in the presence of execution time variation.

cs.CR↗

arXiv2015

Learning Execution Contexts from System Call Distributions for Intrusion Detection in Embedded Systems

Existing techniques used for intrusion detection do not fully utilize the intrinsic properties of embedded systems. In this paper, we propose a lightweight method for detecting anomalous executions using a distribution of system call frequencies. We use a cluster analysis to learn the legitimate execution contexts of embedded applications and then monitor them at run-time to capture abnormal executions. We also present an architectural framework with minor processor modifications to aid in this process. Our prototype shows that the proposed method can effectively detect anomalous executions without relying on sophisticated analyses or affecting the critical execution paths.

cs.CR↗