15 research outputs found
Multi-Agent Consensus Seeking via Large Language Models
Multi-agent systems driven by large language models (LLMs) have shown
promising abilities for solving complex tasks in a collaborative manner. This
work considers a fundamental problem in multi-agent collaboration: consensus
seeking. When multiple agents work together, we are interested in how they can
reach a consensus through inter-agent negotiation. To that end, this work
studies a consensus-seeking task where the state of each agent is a numerical
value and they negotiate with each other to reach a consensus value. It is
revealed that when not explicitly directed on which strategy should be adopted,
the LLM-driven agents primarily use the average strategy for consensus seeking
although they may occasionally use some other strategies. Moreover, this work
analyzes the impact of the agent number, agent personality, and network
topology on the negotiation process. The findings reported in this work can
potentially lay the foundations for understanding the behaviors of LLM-driven
multi-agent systems for solving more complex tasks. Furthermore, LLM-driven
consensus seeking is applied to a multi-robot aggregation task. This
application demonstrates the potential of LLM-driven agents to achieve
zero-shot autonomous planning for multi-robot collaboration tasks. Project
website: westlakeintelligentrobotics.github.io/ConsensusLLM/
Optimal Spatial-Temporal Triangulation for Bearing-Only Cooperative Motion Estimation
Vision-based cooperative motion estimation is an important problem for many
multi-robot systems such as cooperative aerial target pursuit. This problem can
be formulated as bearing-only cooperative motion estimation, where the visual
measurement is modeled as a bearing vector pointing from the camera to the
target. The conventional approaches for bearing-only cooperative estimation are
mainly based on the framework distributed Kalman filtering (DKF). In this
paper, we propose a new optimal bearing-only cooperative estimation algorithm,
named spatial-temporal triangulation, based on the method of distributed
recursive least squares, which provides a more flexible framework for designing
distributed estimators than DKF. The design of the algorithm fully incorporates
all the available information and the specific triangulation geometric
constraint. As a result, the algorithm has superior estimation performance than
the state-of-the-art DKF algorithms in terms of both accuracy and convergence
speed as verified by numerical simulation. We rigorously prove the exponential
convergence of the proposed algorithm. Moreover, to verify the effectiveness of
the proposed algorithm under practical challenging conditions, we develop a
vision-based cooperative aerial target pursuit system, which is the first of
such fully autonomous systems so far to the best of our knowledge
Complex evolution of the lower crust beneath the southeastern North China Craton : the Junan xenoliths and xenocrysts
Knowledge of the lower crust beneath the southeastern parts of North China Craton (NCC) is still sparse. The Junan basalts (67 Ma) in the southeastern NCC contain abundant xenoliths of lower crustal granulites, pyroxenites and mantle peridotites. We present integrated in-situ U-Pb ages and Hf isotopes of zircons from the Junan basalts and granulite xenoliths, to investigate accretion and modification processes in the lower crust. The granulite xenoliths define three distinct U-Pb age populations of ca 2.3 Ga, ca 2.0 Ga and 114-126 Ma. The ca 2.3 Ga zircons have widely variable ℇHf(t) and Paleo-Neoarchean model ages (Tcrust=2.6-4.0 Ga), whereas the ca 2.0 Ga structureless grains give negative ℇHf(t) and Tcrust of 2.7-3.3 Ga. In addition to a few discordant Early Paleoproterozoic xenocrysts, zircons from the basalts are dominantly Early Cretaceous (115-125 Ma), with some Neoproterozoic (550-800 Ma) and Early Paleozoic (437-493 Ma), as well as minor Late Triassic and Late Jurassic grains. These results, combined with previous petrological and geochemical studies and P-T estimates, suggest that the upper part of the Junan lower crust consists of mafic-intermediate granulites, mainly formed at ca 2.3 Ga by crystallization of depleted-mantle-derived magmas that assimilated ancient crust and then fractionated. More significantly, zircon ages and Hf isotopes imply that this lower crust had a complex history of accretion and modification, including initial growth at 3.0-4.0 Ga and 2.5-2.7 Ga, conversion to the dominant granulitic assemblages in the Early Paleoproterozoic (ca 2.3 Ga), modification or metamorphism in the Late Paleoproterozoic (1.8-2.0 Ga) and possibly slight heating in Neoproterozoic time. Episodic thermal events during the Early Paleozoic, Late Triassic and Late Jurassic may also have reworked this Precambrian lower crust. Most of the Early Cretaceous zircons and xenocrysts have uniform ℇHf(t) values similar to those of the nearby coeval magmatic rocks that derived from the enriched lithospheric mantle. This suggests that the Early Cretaceous basaltic underplating, which was contemporary with extensive partial melting of the enriched parts of the NCC lithospheric mantle at the peak of lithospheric thinning, might have substantially modified the Paleoproterozoic granulitic lower crust, and finally gave the diverse cumulate pyroxenites that now make up the deeper lower crust. The discovery of ca 2.1-2.3 Ga lower crust in the southeastern NCC also highlights the heterogeneous nature of the Precambrian lower crust across the eastern NCC.14 page(s
Differences in TCR-Vβ Repertoire and Effector Phenotype between Tumor Infiltrating Lymphocytes and Peripheral Blood Lymphocytes Increase with Age
<div><p>Tumor infiltrating lymphocytes (TIL) reflect the host's anti-tumor immune response, and can be a valuable predictor of prognosis. However, many properties of TIL are not fully understood. In the present study, TCR-Vβ repertoires of cancer patients were primarily analyzed by flow cytometry. Abnormally expressed TCR-Vβ subfamilies were generally found in both TIL and peripheral blood lymphocytes (PBL) of each patient. Of note, increased patient age was associated with increasingly biased TCR-Vβ repertoire in TIL but not in PBL, and the dispersion degree of the differences of TCR-Vβ subfamilies between TIL and PBL correlated positively with age (<i>P</i> = 0.007). Utilizing immunoscope analysis, we identified the age-related reduction in TCR-Vβ diversity, but polyclonal pattern was predominant in significantly expanded TCR-Vβ subfamilies. In addition, we found that older patients possessed a decreased ratio of CD8<sup>+</sup>CD62L<sup>+</sup> non-effector cells in TIL compared to PBL, implying age-related increase of CD8<sup>+</sup>CD62L<sup>−</sup> effector cells in TIL. The colocalization analysis of CD8 and CD3, however, suggested the suppressed activity of these effector cells in tumor microenvironment. These findings further elucidate the properties of TIL, showing an increasing difference between TIL and PBL with age, which may provide insight for the development of effective immunotherapies for cancer patients of different ages.</p></div
Analysis of clonal expansion in TIL of 5 lung cancer patients.
<p>Seven TCR subfamilies (BV3, BV7, BV8, BV13, BV16, BV17, and BV21) overexpressed in TIL of five lung cancer patients were selected to show the CDR length distribution. Decreased numbers and/or biased distribution of CDR3 peaks with increased age of patients were shown. TCRBV21, which did not display remarkable overexpression by FCM detection, but showed oligoclonal/monoclonal expansion pattern in 3 out of 5 TIL specimens, was selected as the control. The numbers in brackets are the ages of patients. The arrows point to monoclonal expansion peaks. The triangle (â–´) means overexpression, and inverted-triangle (â–¾) means underexpression, as shown in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0102327#pone-0102327-g001" target="_blank">Figure 1</a>.</p
TCR repertoire in TIL and PBL of cancer patients.
<p>The TIL or peripheral blood lymphocytes were stained with anti-CD3 and 24 anti-TCRBV antibodies from a TCR Vβ Repertoire Kit. After lysing erythrocytes, washing, and fixing, TIL or PBL were subjected to FCM analysis. For a given TCRBV subfamily expression, any value higher or lower than the mean of the healthy control group, plus or minus 3 SD, was considered abnormal expression (higher labeled with triangle ▴; lower labeled with inverted-triangle ▾). PL indicates patient with lung cancer, PC indicates patient with colon cancer, PH indicates patient with liver cancer.</p
Colocalization analysis of CD3 and CD8 on TIL of patients and on PBL of healthy controls.
<p>TIL of cancer patients and PBL of healthy controls, either freshly isolated (<b>A</b>) or stimulated (<b>B</b>) with 1000 U/ml IFN-γ (at day 0), 50 ng/ml OKT3 (at day 1) and 500 U/ml IL-2 (from day 1 onward to day 6), were separately incubated with mAbs, CD8-FITC and CD3-PC5. The cells were observed with a confocal laser scanning microscope. The colocalization of CD3 and CD8 was analyzed, and colocalization index (r) was calculated by FV10-ASW2.1 software. For each group, 30 different cells from 3 individual were used for calculating the colocalization index (<b>C</b>). *<i>P</i><0.05; **<i>P</i><0.01, unpaired 2-tailed Student's <i>t</i> test.</p
Changed T cell subsets.
<p>The freshly isolated TIL or peripheral blood was stained with directly conjugated mouse mAbs against human antigens, CD45RO-ECD/CD8-FITC, or CD3-PC5/CD8-FITC/CD62L-PE. The ratios of percentage of CD8<sup>+</sup>CD62L<sup>+</sup> subset (gated CD3<sup>+</sup> cells) in TIL to that in coupled PBL (<b>A</b>) and percentage of CD45RO<sup>+</sup>CD8<sup>+</sup> subset in TIL to that in coupled PBL (<b>B</b>) were matched with the ages of patients. The coupled percentages of CD8<sup>+</sup>CD62L<sup>+</sup> subset (gated CD3<sup>+</sup> cells) in TIL and PBL (<b>C</b>) and CD45RO<sup>+</sup>CD8<sup>+</sup> subset in TIL and PBL (<b>D</b>) were matched with the ages of patients. The data for PBL of patient PC2 (age 44) is not available.</p