Study of the Lorentz force on debris with high area-to-mass ratios

The presence of plasma in Low Earth Orbit and above can be the cause of electrostatic charging on space objects with a conductive surface, which then become subject to the Lorentz force induced by the magnetic field. This paper investigates it effects on the trajectory of orbital debris with a high area-to-mass ratio, as their course is particularly influenced by non-gravitational perturbations such as atmospheric drag or solar radiation pressure. Depending on the altitude (low or medium) and the available data, different charging models have been coupled with an orbit propagator, featuring a range of non-Keplerian accelerations and both three and six degrees-of-freedom dynamics. In particular, there has been a focus on long-term effects by simulating charged versus non-charged objects over the time span of years or decades

RaLLe: A Framework for Developing and Evaluating Retrieval-Augmented Large Language Models

Retrieval-augmented large language models (R-LLMs) combine pre-trained large language models (LLMs) with information retrieval systems to improve the accuracy of factual question-answering. However, current libraries for building R-LLMs provide high-level abstractions without sufficient transparency for evaluating and optimizing prompts within specific inference processes such as retrieval and generation. To address this gap, we present RaLLe, an open-source framework designed to facilitate the development, evaluation, and optimization of R-LLMs for knowledge-intensive tasks. With RaLLe, developers can easily develop and evaluate R-LLMs, improving hand-crafted prompts, assessing individual inference processes, and objectively measuring overall system performance quantitatively. By leveraging these features, developers can enhance the performance and accuracy of their R-LLMs in knowledge-intensive generation tasks. We open-source our code at https://github.com/yhoshi3/RaLLe.Comment: 18 pages, 2 figures, see https://youtu.be/JYbm75qnfTg for the demonstration screencas

宇宙機能動帯電モデルとその宇宙推進システムへの応用に関する研究

京都大学0048新制・課程博士博士(工学)甲第21069号工博第4433号新制||工||1689(附属図書館)京都大学大学院工学研究科電気工学専攻(主査)教授 山川 宏, 教授 松尾 哲司, 准教授 海老原 祐輔学位規則第4条第1項該当Doctor of Philosophy (Engineering)Kyoto UniversityDFA

Thrust calculation of electric solar wind sail by particle-in-cell simulation

In this study, thrust characteristics of an electric solar wind sail were numerically evaluated using full three-dimensional particle-in-cell (PIC) simulation. The thrust obtained from the PIC simulation was lower than the thrust estimations obtained in previous studies. The PIC simulation indicated that ambient electrons strongly shield the electrostatic potential of the tether of the sail, and the strong shield effect causes a greater thrust reduction than has been obtained in previous studies. Additionally, previous expressions of the thrust estimation were modified by using the shielded potential structure derived from the present simulation results. The modified thrust estimation agreed very well with the thrust obtained from the PIC simulation

Surgery to Avoid Stoma Construction in Invasive Prostate Cancer Extensively Infiltrating the Rectum

A 61-year-old man tested positive for occult urinary and fecal occult blood and was diagnosed with invasive prostate cancer extensively infiltrating the rectum. After scrutiny, he was diagnosed with cT4N1M0 prostate cancer, and androgen deprivation therapy (ADT) was initiated with a gonadotropin-releasing hormone antagonist. A prostatic rectal resection was performed 6 months after ADT began. The bladder and urethra were anastomosed, the anus was preserved intact, and the sigmoid colon was anastomosed to the anus. A temporary ileostomy was constructed to allow eating and to prevent fistula formation. The ileostomy was closed 5 months post-operation as the patient wanted to live without a stoma. Although the patient died of other disease factors, he remained untreated for 1 year and 7 months post-operation, and his symptoms and disease control were well supported. We report that we were able to perform stoma-free surgical treatment for prostate cancer extensively infiltrating rectum