arXiv subjects

Jialun Zhang

Publications and source records attributed to Jialun Zhang.

7 recordsLinked to original sources

arXiv2026

FRESCO: Complete and Scalable Temporal Safety for CHERI Application Processors

CHERI provides hardware-enforced spatial memory safety. While prior work extends it with heap temporal safety, stack use-after-return remains unaddressed. Existing defenses fall short: compiler analysis reliably catches only references that escape as function return values, while dynamic sanitizers impose overheads that preclude production deployment. We present FRESCO, built on the principle that a stack capability must not outlive the frame that created it. FRESCO "colors" the stack pointer with per-invocation provenance identifiers; every capability derived from it inherits that lifetime and is hardware-invalidated the moment the function exits, regardless of how or where it escaped. Because stack frames retire orders of magnitude more frequently than heap allocations, FRESCO manages the resulting color pressure through: 1) Color Saver, a static capability-aware escape analysis that confines coloring to functions needing it, and whose core algorithm we mechanically verify in Rocq, and 2) capability-color segmentation, which partitions memory into disjoint segments, each with an independent color namespace. Color segmentation lets stack and heap temporal safety coexist on one system, making FRESCO the first hardware/software co-design to provide complete and scalable temporal safety for CHERI application processors. We realize FRESCO on the CHERI-RISC-V QEMU full-system emulator and the out-of-order CHERI-Toooba FPGA softcore, with software support in the CHERI-enabled Clang/LLVM compiler and CheriBSD OS. FRESCO systematically prevents use-after-return, use-after-free, and double-free across the NIST Juliet Test Suite and CVEs, with only a small run-time overhead in SPEC CPU (4% g.m.), SQLite, and PostgreSQL (10-14%).

cs.CR↗

arXiv2026

SandCell: Sandboxing Rust Beyond Unsafe Code

Rust is a modern systems programming language that ensures memory safety by enforcing ownership and borrowing rules at compile time. While the unsafe keyword allows programmers to bypass these restrictions, it introduces significant risks. Various approaches for isolating unsafe code to protect safe Rust from vulnerabilities have been proposed, yet these methods provide only fixed isolation boundaries and do not accommodate expressive policies that require sandboxing both safe and unsafe code. This paper presents SandCell for flexible and lightweight isolation in Rust by leveraging existing syntactic boundaries. SandCell allows programmers to specify which components to sandbox with minimal annotation effort, enabling fine-grained control over isolation. The system also introduces novel techniques to minimize overhead when transferring data between sandboxes. Our evaluation demonstrates SandCell's effectiveness in preventing vulnerabilities across various Rust applications while maintaining reasonable performance overheads.

cs.SE↗

arXiv2026

Fast frequency response with heterogeneous communication delay management under the SCION Internet architecture

System operators can increasingly exploit distributed energy resources (DERs) and controllable loads (CLs) to provide frequency response services. In conventional practice, communication between the system operator and flexible devices relies on the Border Gateway Protocol (BGP)-based Internet. However, existing BGP-based architectures face challenges in providing latency-guaranteed control, while direct private and proprietary communication networks lead to additional deployment and maintenance costs. In contrast, the SCION-based Internet architecture supports latency-minimum path selection, which makes it suitable for latency-sensitive frequency contingency services such as fast frequency response (FFR). Hence, this paper proposes a real-time reserve dispatch framework to optimally select a portfolio of flexible devices to deliver FFR services using the SCION-based Internet. First, an analytical expression of the system frequency dynamics with respect to heterogeneous communication latencies is derived. Next, a cyber-physical co-optimization model is formulated to jointly schedule communication paths and physical flexibility resources for real-time FFR provision. To improve the computation efficiency, we propose a heuristic FFR allocation algorithm to approximate the optimal response portfolio, integrating contributions from both DERs and CLs. Numerical case studies demonstrate the benefits of the proposed algorithm and its capability to approximate the optimality of the reserves allocation while significantly reducing the computation time.

eess.SY↗

arXiv2023

Interval Parsing Grammars for File Format Parsing

File formats specify how data is encoded for persistent storage. They cannot be formalized as context-free grammars since their specifications include context-sensitive patterns such as the random access pattern and the type-length-value pattern. We propose a new grammar mechanism called Interval Parsing Grammars IPGs) for file format specifications. An IPG attaches to every nonterminal/terminal an interval, which specifies the range of input the nonterminal/terminal consumes. By connecting intervals and attributes, the context-sensitive patterns in file formats can be well handled. In this paper, we formalize IPGs' syntax as well as its semantics, and its semantics naturally leads to a parser generator that generates a recursive-descent parser from an IPG. In general, IPGs are declarative, modular, and enable termination checking. We have used IPGs to specify a number of file formats including ZIP, ELF, GIF, PE, and part of PDF; we have also evaluated the performance of the generated parsers.

cs.PL↗

arXiv2022

RMGN: A Regional Mask Guided Network for Parser-free Virtual Try-on

Virtual try-on(VTON) aims at fitting target clothes to reference person images, which is widely adopted in e-commerce.Existing VTON approaches can be narrowly categorized into Parser-Based(PB) and Parser-Free(PF) by whether relying on the parser information to mask the persons' clothes and synthesize try-on images. Although abandoning parser information has improved the applicability of PF methods, the ability of detail synthesizing has also been sacrificed. As a result, the distraction from original cloth may persistin synthesized images, especially in complicated postures and high resolution applications. To address the aforementioned issue, we propose a novel PF method named Regional Mask Guided Network(RMGN). More specifically, a regional mask is proposed to explicitly fuse the features of target clothes and reference persons so that the persisted distraction can be eliminated. A posture awareness loss and a multi-level feature extractor are further proposed to handle the complicated postures and synthesize high resolution images. Extensive experiments demonstrate that our proposed RMGN outperforms both state-of-the-art PB and PF methods.Ablation studies further verify the effectiveness ofmodules in RMGN.

cs.CV↗

arXiv2021

Cost-Oriented Load Forecasting

Accurate load prediction is an effective way to reduce power system operation costs. Traditionally, the mean square error (MSE) is a common-used loss function to guide the training of an accurate load forecasting model. However, the MSE loss function is unable to precisely reflect the real costs associated with forecasting errors because the cost caused by forecasting errors in the real power system is probably neither symmetric nor quadratic. To tackle this issue, this paper proposes a generalized cost-oriented load forecasting framework. Specifically, how to obtain a differentiable loss function that reflects real cost and how to integrate the loss function with regression models are studied. The economy and effectiveness of the proposed load forecasting method are verified by the case studies of an optimal dispatch problem that is built on the IEEE 30-bus system and the open load dataset from the Global Energy Forecasting Competition 2012 (GEFCom2012).

eess.SY↗

arXiv2017

Weak Solution of a Doubly Degenerate Parabolic Equation

This paper studies a fourth-order, nonlinear, doubly-degenerate parabolic equation derived from the thin film equation in spherical geometry. A regularization method is used to study the equation and several useful estimates are obtained. The main result of this paper is to prove the existence of a weak solution of the equation in a weighted Sobolev space.

math.AP↗