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Junhyeok Park

Publications and source records attributed to Junhyeok Park.

7 recordsLinked to original sources

RAF-VLA: Representation Alignment with the Future for End-to-End Autonomous Driving

Recent Vision-Language-Action (VLA) models for autonomous driving have incorporated world modeling by predicting future driving scenes alongside driving actions, demonstrating strong planning performance. Future driving scenes are utilized as dense supervision, encouraging the policy to learn rich internal representations useful for planning. However, these World-Modeling VLAs rely on explicit future generation to learn such representations, thereby introducing two key limitations: additional training burden and inference latency. To address these limitations, we propose RAF-VLA (Representation Alignment with the Future), a VLA-based autonomous driving framework that shapes planning-relevant internal representations through direct guidance from future-frame representations. RAF-VLA employs Future-Aligned Supervised Fine-Tuning, in which a straightforward regularization aligns the policy's hidden states with future-frame representations obtained from a pretrained world encoder while learning driving actions. This simple alignment allows RAF-VLA to avoid the training burden and inference latency associated with future generation. Extensive experiments on the NAVSIM benchmark show that RAF-VLA achieves competitive planning performance against state-of-the-art VLA planners with substantially fewer training samples seen. Moreover, RAF-VLA incurs only 3.8% training overhead and a negligible 1 ms inference overhead.

cs.RO

RLDX-1 Technical Report

While Vision-Language-Action models (VLAs) have shown remarkable progress toward human-like generalist robotic policies through the versatile intelligence (i.e. broad scene understanding and language-conditioned generalization) inherited from pre-trained Vision-Language Models, they still struggle with complex real-world tasks requiring broader functional capabilities (e.g. motion awareness, long-term memory, and physical sensing). To address this, we introduce RLDX-1, a general-purpose robotic policy for dexterous manipulation built on the Multi-Stream Action Transformer (MSAT), an architecture that unifies these capabilities by integrating heterogeneous modalities through modality-specific streams with cross-modal joint self-attention. RLDX-1 further combines this architecture with system-level design choices, including data synthesis for rare manipulation scenarios, learning procedures specialized for human-like manipulation, and inference optimizations for real-time deployment. Through empirical evaluation, we show that RLDX-1 consistently outperforms recent frontier VLAs (e.g. $π_{0.5}$ and GR00T N1.6) across both simulation benchmarks and real-world tasks that require broad functional capabilities beyond general versatility. In particular, RLDX-1 shows superiority in ALLEX humanoid tasks by achieving success rates of 86.8% while $π_{0.5}$ and GR00T N1.6 achieve around 40%, highlighting the ability of RLDX-1 to control a high-DoF humanoid robot under diverse functional demands. Together, these results position RLDX-1 as a promising step toward reliable VLAs for complex, contact-rich, and dynamic real-world dexterous manipulation.

cs.RO

Structural characterization and bonding energy analysis for plasma-activated bonding of SiCN films: A reactive molecular dynamics study

Plasma-activated bonding of SiCN films offers high bonding strength at the hybrid-bonding interface, thereby enhancing mechanical reliability. Although experimental studies have shown that the interfacial bonding properties of SiCN films vary with SiCN composition and plasma treatment parameters, a clear correlation between these parameters and the resulting bonding properties has not yet been established. This study presents an atomistic investigation of SiCN-SiCN plasma-activated bonding with controlled SiCN composition and plasma fluence, which performs O2 plasma surface activation, surface hydroxylation, direct bonding, post-bonding annealing, and debonding using reactive molecular dynamics. The structural characterization of the plasma-activated SiCN surface, including density of various covalent bonds and surface roughness, exhibits composition- and plasma fluence-dependent chemical and morphological modification. Bonding energy evaluated from atomic traction-separation responses in cohesive zone volume elements (CZVE) during debonding simulations shows a positive correlation with the interfacial Si-O-Si density. Since the interfacial Si-O-Si density reflects the combined effects of these chemical and morphological modifications, the dependence of bonding energy on composition and plasma fluence is successfully elucidated by the structural characterization. These results establish an atomic-level material-process-property relationship and offer practical guidance for optimizing SiCN composition and plasma treatment parameters for SiCN-SiCN plasma-activated bonding.

cond-mat.mtrl-sci

OASIS: Object-based Analytics Storage for Intelligent SQL Query Offloading in Scientific Tabular Workloads

Computation-Enabled Object Storage (COS) systems, such as MinIO and Ceph, have recently emerged as promising storage solutions for post hoc, SQL-based analysis on large-scale datasets in High-Performance Computing (HPC) environments. By supporting object-granular layouts, COS facilitates column-oriented access and supports in-storage execution of data reduction operators, such as filters, close to where the data resides. Despite growing interest and adoption, existing COS systems exhibit several fundamental limitations that hinder their effectiveness. First, they impose rigid constraints on output data formats, limiting flexibility and interoperability. Second, they support offloading for only a narrow set of operators and expressions, restricting their applicability to more complex analytical tasks. Third--and perhaps most critically--they fail to incorporate design strategies that enable compute offloading optimized for the characteristics of deep storage hierarchies. To address these challenges, this paper proposes OASIS, a novel COS system that features: (i) flexible and interoperable output delivery through diverse formats, including columnar layouts such as Arrow; (ii) broad support for complex operators (e.g., aggregate, sort) and array-aware expressions, including element-wise predicates over array structures; and (iii) dynamic selection of optimal execution paths across internal storage layers, guided by operator characteristics and data movement costs. We implemented a prototype of OASIS and integrated it into the Spark analytics framework. Through extensive evaluation using real-world scientific queries from HPC workflows, OASIS achieves up to a 32.7% performance improvement over Spark configured with existing COS-based storage systems.

cs.DB

OpenCXD: An Open Real-Device-Guided Hybrid Evaluation Framework for CXL-SSDs

The advent of Compute Express Link (CXL) enables SSDs to participate in the memory hierarchy as large-capacity, byte-addressable memory devices. These CXL-enabled SSDs (CXL-SSDs) offer a promising new tier between DRAM and traditional storage, combining NAND flash density with memory-like access semantics. However, evaluating the performance of CXL-SSDs remains difficult due to the lack of hardware that natively supports the CXL.mem protocol on SSDs. As a result, most prior work relies on hybrid simulators combining CPU models augmented with CXL.mem semantics and SSD simulators that approximate internal flash behaviors. While effective for early-stage exploration, this approach cannot faithfully model firmware-level interactions and low-level storage dynamics critical to CXL-SSD performance. In this paper, we present OpenCXD, a real-device-guided hybrid evaluation framework that bridges the gap between simulation and hardware. OpenCXD integrates a cycle-accurate CXL.mem simulator on the host side with a physical OpenSSD platform running real firmware. This enables in-situ firmware execution triggered by simulated memory requests. Through these contributions, OpenCXD reflects device-level phenomena unobservable in simulation-only setups, providing critical insights for future firmware design tailored to CXL-SSDs.

cs.AR

A Host-SSD Collaborative Write Accelerator for LSM-Tree-Based Key-Value Stores

Log-Structured Merge (LSM) tree-based Key-Value Stores (KVSs) are widely adopted for their high performance in write-intensive environments, but they often face performance degradation due to write stalls during compaction. Prior solutions, such as regulating I/O traffic or using multiple compaction threads, can cause unexpected drops in throughput or increase host CPU usage, while hardware-based approaches using FPGA, GPU, and DPU aimed at reducing compaction duration introduce additional hardware costs. In this study, we propose KVACCEL, a novel hardware-software co-design framework that eliminates write stalls by leveraging a dual-interface SSD. KVACCEL allocates logical NAND flash space to support both block and key-value interfaces, using the key-value interface as a temporary write buffer during write stalls. This strategy significantly reduces write stalls, optimizes resource usage, and ensures consistency between the host and device by implementing an in-device LSM-based write buffer with an iterator-based range scan mechanism. Our extensive evaluation shows that for write-intensive workloads, KVACCEL outperforms ADOC by up to 1.17x in terms of throughput and performance-to-CPU-utilization efficiency. For mixed read-write workloads, both demonstrate comparable performance.

cs.AR

Solution for SMART-101 Challenge of CVPR Multi-modal Algorithmic Reasoning Task 2024

In this paper, the solution of HYU MLLAB KT Team to the Multimodal Algorithmic Reasoning Task: SMART-101 CVPR 2024 Challenge is presented. Beyond conventional visual question-answering problems, the SMART-101 challenge aims to achieve human-level multimodal understanding by tackling complex visio-linguistic puzzles designed for children in the 6-8 age group. To solve this problem, we suggest two main ideas. First, to utilize the reasoning ability of a large-scale language model (LLM), the given visual cues (images) are grounded in the text modality. For this purpose, we generate highly detailed text captions that describe the context of the image and use these captions as input for the LLM. Second, due to the nature of puzzle images, which often contain various geometric visual patterns, we utilize an object detection algorithm to ensure these patterns are not overlooked in the captioning process. We employed the SAM algorithm, which can detect various-size objects, to capture the visual features of these geometric patterns and used this information as input for the LLM. Under the puzzle split configuration, we achieved an option selection accuracy Oacc of 29.5 on the test set and a weighted option selection accuracy (WOSA) of 27.1 on the challenge set.

cs.CV