Existing RAG benchmarks often overlook query difficulty, leading to inflated performance on simpler questions and unreliable evaluations. A robust benchmark dataset must satisfy three key criteria: quality, diversity, and difficulty, which capturing the complexity of reasoning based on hops and the distribution of supporting evidence. In this paper, we propose MHTS (Multi-Hop Tree Structure), a novel dataset synthesis framework that systematically controls multi-hop reasoning complexity by leveraging a multi-hop tree structure to generate logically connected, multi-chunk queries. Our fine-grained difficulty estimation formula exhibits a strong correlation with the overall performance metrics of a RAG system, validating its effectiveness in assessing both retrieval and answer generation capabilities. By ensuring high-quality, diverse, and difficulty-controlled queries, our approach enhances RAG evaluation and benchmarking capabilities.

We present SAVER, a new memory-error repair technique for C programs. Memory errors such as memory leak, double-free, and use-after-free are highly prevalent and fixing them requires significant effort. Automated program repair techniques hold the promise of reducing this burden but the state-of-the-art is still unsatisfactory. In particular, no existing techniques are able to fix those errors in a scalable, precise, and safe way, all of which are required for a truly practical tool. SAVER aims to address these shortcomings. To this end, we propose a method based on a novel representation of the program called object flow graph, which summarizes the program's heap-related behavior using static analysis. We show that fixing memory errors can be formulated as a graph labeling problem over object flow graph and present an efficient algorithm. We evaluated SAVER in combination with Infer, an industrial-strength static bug-finder, and show that 74% of the reported errors can be fixed automatically for a range of open-source C programs.

In this paper, a wearable hand system for virtual reality is proposed. The proposed system can deliver accurate force to three fingertips (thumb, index, and middle fingers), which play dominant roles in manipulating and interacting with the external environment, and also measure fingertip positions of the three fingers. The proposed system has five degrees of freedom (DOFs) for each finger structure to permit natural finger motion, can be easily worn by clicking the silicon-coated fingertip structures and buckling the wearable structure around the palm. The forces delivered to the fingertips are controlled by the motor current with the robust control algorithm, and the fingertip position is calculated by forward kinematics. The performance of the proposed system was verified experimentally; the calculated fingertip position was compared to a camera-based motion capture system and interactions with objects of different stiffness were tested.

In this paper, a wearable sensing glove for measuring the motion of the fingers is proposed. The system consists of linear potentiometers, flexible wires, and linear springs, which makes it compact and lightweight so that it does not interfere with the natural motion of the fingers. Inspired by the way wrinkles on finger joints are smoothed out when the finger is flexed, a flexible wire is attached to the back of each finger. As the flexible wire moves due to the motion of the finger, the joint angles are calculated by measuring the change in length of wire. Linear potentiometers with linear springs were used to maintain the tension of the wires in order to measure the wire length change consistently. Because the motion of the proximal interphalangeal (PIP) joint is dependent on that of the distal interphalangeal (DIP) joint, only two linear potentiometers were used for each finger. A compact sensing module including 10 linear potentiometers and springs was attached to a glove. The proposed system can widely be applied for the systems, which require to measure finger motions accurately, e.g., virtual reality or teleoperation systems. Such feasible applications were actually implemented and introduced in this paper.