Optimization
Deep Dependency Networks and Advanced Inference Schemes for Multi-Label Classification
Arya, Shivvrat, Xiang, Yu, Gogate, Vibhav
We present a unified framework called deep dependency networks (DDNs) that combines dependency networks and deep learning architectures for multi-label classification, with a particular emphasis on image and video data. The primary advantage of dependency networks is their ease of training, in contrast to other probabilistic graphical models like Markov networks. In particular, when combined with deep learning architectures, they provide an intuitive, easy-to-use loss function for multi-label classification. A drawback of DDNs compared to Markov networks is their lack of advanced inference schemes, necessitating the use of Gibbs sampling. To address this challenge, we propose novel inference schemes based on local search and integer linear programming for computing the most likely assignment to the labels given observations. We evaluate our novel methods on three video datasets (Charades, TACoS, Wetlab) and three image datasets (MS-COCO, PASCAL VOC, NUS-WIDE), comparing their performance with (a) basic neural architectures and (b) neural architectures combined with Markov networks equipped with advanced inference and learning techniques. Our results demonstrate the superiority of our new DDN methods over the two competing approaches.
MPCOM: Robotic Data Gathering with Radio Mapping and Model Predictive Communication
Ji, Zhiyou, Li, Guoliang, Han, Ruihua, Wang, Shuai, Bai, Bing, Xu, Wei, Ye, Kejiang, Xu, Chengzhong
Robotic data gathering (RDG) is an emerging paradigm that navigates a robot to harvest data from remote sensors. However, motion planning in this paradigm needs to maximize the RDG efficiency instead of the navigation efficiency, for which the existing motion planning methods become inefficient, as they plan robot trajectories merely according to motion factors. This paper proposes radio map guided model predictive communication (MPCOM), which navigates the robot with both grid and radio maps for shape-aware collision avoidance and communication-aware trajectory generation in a dynamic environment. The proposed MPCOM is able to trade off the time spent on reaching goal, avoiding collision, and improving communication. MPCOM captures high-order signal propagation characteristics using radio maps and incorporates the map-guided communication regularizer to the motion planning block. Experiments in IRSIM and CARLA simulators show that the proposed MPCOM outperforms other benchmarks in both LOS and NLOS cases. Real-world testing based on car-like robots is also provided to demonstrate the effectiveness of MPCOM in indoor environments.
ESFL: Efficient Split Federated Learning over Resource-Constrained Heterogeneous Wireless Devices
Zhu, Guangyu, Deng, Yiqin, Chen, Xianhao, Zhang, Haixia, Fang, Yuguang, Wong, Tan F.
Federated learning (FL) allows multiple parties (distributed devices) to train a machine learning model without sharing raw data. How to effectively and efficiently utilize the resources on devices and the central server is a highly interesting yet challenging problem. In this paper, we propose an efficient split federated learning algorithm (ESFL) to take full advantage of the powerful computing capabilities at a central server under a split federated learning framework with heterogeneous end devices (EDs). By splitting the model into different submodels between the server and EDs, our approach jointly optimizes user-side workload and server-side computing resource allocation by considering users' heterogeneity. We formulate the whole optimization problem as a mixed-integer non-linear program, which is an NP-hard problem, and develop an iterative approach to obtain an approximate solution efficiently. Extensive simulations have been conducted to validate the significantly increased efficiency of our ESFL approach compared with standard federated learning, split learning, and splitfed learning.
PyTorchGeoNodes: Enabling Differentiable Shape Programs for 3D Shape Reconstruction
Stekovic, Sinisa, Ainetter, Stefan, D'Urso, Mattia, Fraundorfer, Friedrich, Lepetit, Vincent
We propose PyTorchGeoNodes, a differentiable module for reconstructing 3D objects from images using interpretable shape programs. In comparison to traditional CAD model retrieval methods, the use of shape programs for 3D reconstruction allows for reasoning about the semantic properties of reconstructed objects, editing, low memory footprint, etc. However, the utilization of shape programs for 3D scene understanding has been largely neglected in past works. As our main contribution, we enable gradient-based optimization by introducing a module that translates shape programs designed in Blender, for example, into efficient PyTorch code. We also provide a method that relies on PyTorchGeoNodes and is inspired by Monte Carlo Tree Search (MCTS) to jointly optimize discrete and continuous parameters of shape programs and reconstruct 3D objects for input scenes. In our experiments, we apply our algorithm to reconstruct 3D objects in the ScanNet dataset and evaluate our results against CAD model retrieval-based reconstructions. Our experiments indicate that our reconstructions match well the input scenes while enabling semantic reasoning about reconstructed objects.
I/O in Machine Learning Applications on HPC Systems: A 360-degree Survey
Lewis, Noah, Bez, Jean Luca, Byna, Suren
Because of the increased popularity of Machine Learning (ML) workloads, there is a rising demand for I/O systems that can effectively accommodate their distinct I/O access patterns. Write operation bursts commonly dominate traditional workloads; however, ML workloads are usually read-intensive and use many small files [99]. Due to the absence of a well-established consensus on the preferred I/O stack for ML workloads, numerous developers resort to crafting their own ad-hoc algorithms and storage systems to cater to the specific requirements of their applications [50]. This can result in sub-optimal application performance due to the under-utilization of the storage system, prompting the necessity for novel I/O optimization methods tailored to the demands of ML workloads. In Figure 1, we show the evolving I/O stack used for running ML workloads (on the right side) in comparison with the traditional HPC I/O stack (on the left side). Traditional HPC I/O stack has been developed to support massive parallelism. Permission to make digital or hard copies of all or part of this work for personal or classroom use is granted without fee provided that copies are not made or distributed for profit or commercial advantage and that copies bear this notice and the full citation on the first page.
LAECIPS: Large Vision Model Assisted Adaptive Edge-Cloud Collaboration for IoT-based Perception System
Hu, Shijing, Deng, Ruijun, Du, Xin, Lu, Zhihui, Duan, Qiang, He, Yi, Huang, Shih-Chia, Wu, Jie
Recent large vision models (e.g., SAM) enjoy great potential to facilitate intelligent perception with high accuracy. Yet, the resource constraints in the IoT environment tend to limit such large vision models to be locally deployed, incurring considerable inference latency thereby making it difficult to support real-time applications, such as autonomous driving and robotics. Edge-cloud collaboration with large-small model co-inference offers a promising approach to achieving high inference accuracy and low latency. However, existing edge-cloud collaboration methods are tightly coupled with the model architecture and cannot adapt to the dynamic data drifts in heterogeneous IoT environments. To address the issues, we propose LAECIPS, a new edge-cloud collaboration framework. In LAECIPS, both the large vision model on the cloud and the lightweight model on the edge are plug-and-play. We design an edge-cloud collaboration strategy based on hard input mining, optimized for both high accuracy and low latency. We propose to update the edge model and its collaboration strategy with the cloud under the supervision of the large vision model, so as to adapt to the dynamic IoT data streams. Theoretical analysis of LAECIPS proves its feasibility. Experiments conducted in a robotic semantic segmentation system using real-world datasets show that LAECIPS outperforms its state-of-the-art competitors in accuracy, latency, and communication overhead while having better adaptability to dynamic environments.
Machine Learning Based Optimization Workflow for Tuning Numerical Settings of Differential Equation Solvers for Boundary Value Problems
Victor, Viny Saajan, Ettmรผller, Manuel, Schmeiรer, Andre, Leitte, Heike, Gramsch, Simone
Several numerical differential equation solvers have been employed effectively over the years as an alternative to analytical solvers to quickly and conveniently solve differential equations. One category of these is boundary value solvers, which are used to solve real-world problems formulated as differential equations with boundary conditions. These solvers require certain numerical settings to solve the differential equations that affect their solvability and performance. A systematic fine-tuning of these settings is required to obtain the desired solution and performance. Currently, these settings are either selected by trial and error or require domain expertise. In this paper, we propose a machine learning-based optimization workflow for fine-tuning the numerical settings to reduce the time and domain expertise required in the process. In the evaluation section, we discuss the scalability, stability, and reliability of the proposed workflow. We demonstrate our workflow on a numerical boundary value problem solver.
Learning and Optimization for Price-based Demand Response of Electric Vehicle Charging
Gu, Chengyang, Pan, Yuxin, Liu, Ruohong, Chen, Yize
In the context of charging electric vehicles (EVs), the price-based demand response (PBDR) is becoming increasingly significant for charging load management. Such response usually encourages cost-sensitive customers to adjust their energy demand in response to changes in price for financial incentives. Thus, to model and optimize EV charging, it is important for charging station operator to model the PBDR patterns of EV customers by precisely predicting charging demands given price signals. Then the operator refers to these demands to optimize charging station power allocation policy. The standard pipeline involves offline fitting of a PBDR function based on historical EV charging records, followed by applying estimated EV demands in downstream charging station operation optimization. In this work, we propose a new decision-focused end-to-end framework for PBDR modeling that combines prediction errors and downstream optimization cost errors in the model learning stage. We evaluate the effectiveness of our method on a simulation of charging station operation with synthetic PBDR patterns of EV customers, and experimental results demonstrate that this framework can provide a more reliable prediction model for the ultimate optimization process, leading to more effective optimization solutions in terms of cost savings and charging station operation objectives with only a few training samples.
Automated Discovery of Functional Actual Causes in Complex Environments
Chuck, Caleb, Vaidyanathan, Sankaran, Giguere, Stephen, Zhang, Amy, Jensen, David, Niekum, Scott
Reinforcement learning (RL) algorithms often struggle to learn policies that generalize to novel situations due to issues such as causal confusion, overfitting to irrelevant factors, and failure to isolate control of state factors. These issues stem from a common source: a failure to accurately identify and exploit state-specific causal relationships in the environment. While some prior works in RL aim to identify these relationships explicitly, they rely on informal domain-specific heuristics such as spatial and temporal proximity. Actual causality offers a principled and general framework for determining the causes of particular events. However, existing definitions of actual cause often attribute causality to a large number of events, even if many of them rarely influence the outcome. Prior work on actual causality proposes normality as a solution to this problem, but its existing implementations are challenging to scale to complex and continuous-valued RL environments. This paper introduces functional actual cause (FAC), a framework that uses context-specific independencies in the environment to restrict the set of actual causes. We additionally introduce Joint Optimization for Actual Cause Inference (JACI), an algorithm that learns from observational data to infer functional actual causes. We demonstrate empirically that FAC agrees with known results on a suite of examples from the actual causality literature, and JACI identifies actual causes with significantly higher accuracy than existing heuristic methods in a set of complex, continuous-valued environments.
Multi-Robot Connected Fermat Spiral Coverage
We introduce the Multi-Robot Connected Fermat Spiral (MCFS), a novel algorithmic framework for Multi-Robot Coverage Path Planning (MCPP) that adapts Connected Fermat Spiral (CFS) from the computer graphics community to multi-robot coordination for the first time. MCFS uniquely enables the orchestration of multiple robots to generate coverage paths that contour around arbitrarily shaped obstacles, a feature that is notably lacking in traditional methods. Our framework not only enhances area coverage and optimizes task performance, particularly in terms of makespan, for workspaces rich in irregular obstacles but also addresses the challenges of path continuity and curvature critical for non-holonomic robots by generating smooth paths without decomposing the workspace. MCFS solves MCPP by constructing a graph of isolines and transforming MCPP into a combinatorial optimization problem, aiming to minimize the makespan while covering all vertices. Our contributions include developing a unified CFS version for scalable and adaptable MCPP, extending it to MCPP with novel optimization techniques for cost reduction and path continuity and smoothness, and demonstrating through extensive experiments that MCFS outperforms existing MCPP methods in makespan, path curvature, coverage ratio, and overlapping ratio. Our research marks a significant step in MCPP, showcasing the fusion of computer graphics and automated planning principles to advance the capabilities of multi-robot systems in complex environments. Our code is available at https://github.com/reso1/MCFS.