Score based approaches to sampling have shown much success as a generative algorithm to produce new samples from a target density given a pool of initial samples. In this work, we consider if we have no initial samples from the target density, but rather $0^{th}$ and $1^{st}$ order oracle access to the log likelihood. Such problems may arise in Bayesian posterior sampling, or in approximate minimization of non-convex functions. Using this knowledge alone, we propose a Monte Carlo method to estimate the score empirically as a particular expectation of a random variable. Using this estimator, we can then run a discrete version of the backward flow SDE to produce samples from the target density. This approach has the benefit of not relying on a pool of initial samples from the target density, and it does not rely on a neural network or other black box model to estimate the score.
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Representing and reasoning about uncertainty is crucial for autonomous agents acting in partially observable environments with noisy sensors. Partially observable Markov decision processes (POMDPs) serve as a general framework for representing problems in which uncertainty is an important factor. Online sample-based POMDP methods have emerged as efficient approaches to solving large POMDPs and have been shown to extend to continuous domains. However, these solutions struggle to find long-horizon plans in problems with significant uncertainty. Exploration heuristics can help guide planning, but many real-world settings contain significant task-irrelevant uncertainty that might distract from the task objective. In this paper, we propose STRUG, an online POMDP solver capable of handling domains that require long-horizon planning with significant task-relevant and task-irrelevant uncertainty. We demonstrate our solution on several temporally extended versions of toy POMDP problems as well as robotic manipulation of articulated objects using a neural perception frontend to construct a distribution of possible models. Our results show that STRUG outperforms the current sample-based online POMDP solvers on several tasks.
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In this paper, we examine the problem of visibility-aware robot navigation among movable obstacles (VANAMO). A variant of the well-known NAMO robotic planning problem, VANAMO puts additional visibility constraints on robot motion and object movability. This new problem formulation lifts the restrictive assumption that the map is fully visible and the object positions are fully known. We provide a formal definition of the VANAMO problem and propose the Look and Manipulate Backchaining (LaMB) algorithm for solving such problems. LaMB has a simple vision-based API that makes it more easily transferable to real-world robot applications and scales to the large 3D environments. To evaluate LaMB, we construct a set of tasks that illustrate the complex interplay between visibility and object movability that can arise in mobile base manipulation problems in unknown environments. We show that LaMB outperforms NAMO and visibility-aware motion planning approaches as well as simple combinations of them on complex manipulation problems with partial observability.
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Diffusion models have quickly become the go-to paradigm for generative modelling of perceptual signals (such as images and sound) through iterative refinement. Their success hinges on the fact that the underlying physical phenomena are continuous. For inherently discrete and categorical data such as language, various diffusion-inspired alternatives have been proposed. However, the continuous nature of diffusion models conveys many benefits, and in this work we endeavour to preserve it. We propose CDCD, a framework for modelling categorical data with diffusion models that are continuous both in time and input space. We demonstrate its efficacy on several language modelling tasks.
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Researchers produce thousands of scholarly documents containing valuable technical knowledge. The community faces the laborious task of reading these documents to identify, extract, and synthesize information. To automate information gathering, document-level question answering (QA) offers a flexible framework where human-posed questions can be adapted to extract diverse knowledge. Finetuning QA systems requires access to labeled data (tuples of context, question and answer). However, data curation for document QA is uniquely challenging because the context (i.e. answer evidence passage) needs to be retrieved from potentially long, ill-formatted documents. Existing QA datasets sidestep this challenge by providing short, well-defined contexts that are unrealistic in real-world applications. We present a three-stage document QA approach: (1) text extraction from PDF; (2) evidence retrieval from extracted texts to form well-posed contexts; (3) QA to extract knowledge from contexts to return high-quality answers -- extractive, abstractive, or Boolean. Using QASPER for evaluation, our detect-retrieve-comprehend (DRC) system achieves a +7.19 improvement in Answer-F1 over existing baselines while delivering superior context selection. Our results demonstrate that DRC holds tremendous promise as a flexible framework for practical scientific document QA.
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数据是现代机器学习系统的命脉,包括音乐信息检索中的命脉(MIR)。但是,MIR长期以来一直被小型数据集和不可靠的标签所困扰。在这项工作中,我们建议使用生成建模打破这种瓶颈。通过使用室内合奏的结构化合成模型(在URMP上训练的MIDI-DDSP)的结构化合成模型,通过管道说明(在巴赫合唱上训练的椰子)模型,我们演示了一个能够生成无限量的逼真的合唱音乐的系统,其中包括丰富的结合音乐,包括混合,包括混合,,,包括混合,茎,MIDI,笔记级性能属性(Staccato,Vibrato等),甚至是细粒的合成参数(音高,振幅等)。我们称此系统为室内集合发生器(CEG),并使用它来生成来自四个不同腔室合奏(cocochorales)的大型合唱数据集。我们证明,使用我们的方法生成的数据改善了音乐转录和源分离的最新模型,并且我们均发布了系统和数据集作为MIR社区未来工作的开源基础。
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我们提出了GRASP提案网络(GP-NET),这是一种卷积神经网络模型,可以为移动操纵器生成6-DOF GRASP。为了训练GP-NET,我们合成生成一个包含深度图像和地面真相掌握信息的数据集,以供超过1400个对象。在现实世界实验中,我们使用egad!掌握基准测试,以评估两种常用算法的GP-NET,即体积抓地力网络(VGN)和在PAL TIAGO移动操纵器上进行的GRASP抓取网络(VGN)和GRASP姿势检测包(GPD)。GP-NET的掌握率为82.2%,而VGN为57.8%,GPD的成功率为63.3%。与机器人握把中最新的方法相反,GP-NET可以在不限制工作空间的情况下使用移动操纵器抓住对象,用于抓住对象,需要桌子进行分割或需要高端GPU。为了鼓励使用GP-NET,我们在https://aucoroboticsmu.github.io/gp-net/上提供ROS包以及我们的代码和预培训模型。
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在本文中,我们将预处理技术应用于具有不同长度的多通道时间序列数据,我们称之为对齐问题,用于下游机器学习。多种原因可能发生多种渠道时间序列数据的未对准,原因有多种原因,例如丢失的数据,变化的采样率或不一致的收集时间。我们考虑从MIT SuperCloud高性能计算(HPC)中心收集的多渠道时间序列数据,其中不同的工作开始时间和HPC作业的运行时间不同,导致数据不对准。这种未对准使得为计算工作负载分类等任务构建AI/ML方法具有挑战性。在先前使用MIT SuperCloud数据集的监督分类工作的基础上,我们通过三种宽阔的低间接空间方法解决了对齐问题:从全职系列中抽样固定子集,在全职系列上执行摘要统计信息,并对系数进行取样。从映射到频域的时间序列。我们最佳性能模型的分类精度大于95%,以先前的方法对MIT SuperCloud数据集的多通道时间序列分类的表现优于5%。这些结果表明,我们的低间接费用方法与标准机器学习技术结合使用,能够达到高水平的分类准确性,并作为解决对齐问题(例如内核方法)的未来方法的基准。
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预先训练的大语言模型(LLM)(例如OpenAI Codex)通过从非正式自然语言(NL)意图中生成自然代码来自动化编码的重要方面。但是,生成的代码无法满足用户意图的任何正确性保证。实际上,很难定义正确性的概念,因为自然语言可能是模棱两可的,并且缺乏正式的语义。在本文中,我们通过提出测试驱动的用户形式化(TDUIF)的工作流程来解决以上问题的第一步,该工作流利用轻量级用户的反馈共同将用户的意图正式化为测试(部分规范) ),(b)生成符合正式用户意图的代码。要对算法进行可扩展的大规模自动化评估,而无需循环中的用户,我们描述了如何使用参考解决方案模拟用户与高保真性的互动。我们还描述并实施了几种算法组件(包括突变和排名一组测试)的替代实现,这些实现可用于有效解决TDUIF问题。我们已经开发了一个系统的Ticoder,该系统实现了多种解决方案来进行TDUIF,并将其对MBPP学术代码生成基准测试的相对有效性进行了比较。在MBPP上使用OpenAI Codex LLM的结果很有希望:我们的最佳算法将通行证@1代码生成准确度指标从48.39%提高到单个用户查询,最高为85.48%,最多可达55.48%,最多可提供5个用户查询。其次,我们可以生成与用户意图在1.69个用户查询中的非平凡功能单位测试,该数据集为90.40%的示例,用于此数据集。
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水印是保护创作者对数字图像,视频和音频的权利的常用策略。最近,水印方法已扩展到深度学习模型 - 原则上,当对手试图复制该模型时,应保留水印。但是,实际上,智能对手通常可以去除水印。几篇论文提出了水印方法,这些方法声称对不同类型的拆除攻击具有耐药性,但是在面对新的或更好的对手时,这些新技术通常会失败。在本文中,我们提出了一种可认证的水印方法。使用Chiang等人提出的随机平滑技术,我们表明我们的水印是不明显的,除非模型参数的更改超过一定的L2阈值。除了获得认证外,与以前的水印方法相比,我们的水印在经验上也更强。我们的实验可以在https://github.com/arpitbansal297/certified_watermarks上复制。
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