{"title":"A Unified Analysis of Saddle Flow Dynamics: Stability and Algorithm Design","authors":"Pengcheng You, Yingzhu Liu, Enrique Mallada","doi":"arxiv-2409.05290","DOIUrl":"https://doi.org/arxiv-2409.05290","url":null,"abstract":"This work examines the conditions for asymptotic and exponential convergence\u0000of saddle flow dynamics of convex-concave functions. First, we propose an\u0000observability-based certificate for asymptotic convergence, directly bridging\u0000the gap between the invariant set in a LaSalle argument and the equilibrium set\u0000of saddle flows. This certificate generalizes conventional conditions for\u0000convergence, e.g., strict convexity-concavity, and leads to a novel\u0000state-augmentation method that requires minimal assumptions for asymptotic\u0000convergence. We also show that global exponential stability follows from strong\u0000convexity-strong concavity, providing a lower-bound estimate of the convergence\u0000rate. This insight also explains the convergence of proximal saddle flows for\u0000strongly convex-concave objective functions. Our results generalize to dynamics\u0000with projections on the vector field and have applications in solving\u0000constrained convex optimization via primal-dual methods. Based on these\u0000insights, we study four algorithms built upon different Lagrangian function\u0000transformations. We validate our work by applying these methods to solve a\u0000network flow optimization and a Lasso regression problem.","PeriodicalId":501286,"journal":{"name":"arXiv - MATH - Optimization and Control","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142212435","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"A study on two-metric projection methods","authors":"Hanju Wu, Yue Xie","doi":"arxiv-2409.05321","DOIUrl":"https://doi.org/arxiv-2409.05321","url":null,"abstract":"The two-metric projection method is a simple yet elegant algorithm proposed\u0000by Bertsekas in 1984 to address bound/box-constrained optimization problems.\u0000The algorithm's low per-iteration cost and potential for using Hessian\u0000information makes it a favourable computation method for this problem class.\u0000However, its global convergence guarantee is not studied in the nonconvex\u0000regime. In our work, we first investigate the global complexity of such a\u0000method for finding first-order stationary solution. After properly scaling each\u0000step, we equip the algorithm with competitive complexity guarantees.\u0000Furthermore, we generalize the two-metric projection method for solving\u0000$ell_1$-norm minimization and discuss its properties via theoretical\u0000statements and numerical experiments.","PeriodicalId":501286,"journal":{"name":"arXiv - MATH - Optimization and Control","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142212431","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Carbon-Aware Quantification of Real-Time Aggregate Power Flexibility of Electric Vehicles","authors":"Xiaowei Wang, Yue Chen","doi":"arxiv-2409.05597","DOIUrl":"https://doi.org/arxiv-2409.05597","url":null,"abstract":"Electric vehicles (EVs) can be aggregated to offer flexibility services to\u0000the power system. However, the rapid growth in EV adoption leads to increased\u0000grid-level carbon emissions due to higher EV charging demand, complicating grid\u0000decarbonization efforts. Quantifying and managing EV flexibility while\u0000controlling carbon emissions is crucial. This paper introduces a methodology\u0000for carbon-aware quantification of real-time aggregate EV power flexibility. An\u0000offline model is first developed to determine the upper and lower bounds of the\u0000EV flexibility region. To address uncertainties in EV charging behaviors and\u0000grid carbon intensity, we propose a carbon-aware online optimization algorithm\u0000based on Lyapunov optimization, incorporating a queue model to capture system\u0000dynamics. To enhance EV flexibility, we integrate dispatch signals from the\u0000system operator into the queue update through a two-stage disaggregation\u0000process. The proposed approach is prediction-free and adaptable to various\u0000uncertainties. Additionally, the maximum charging delay for EV charging tasks\u0000is theoretically bounded by a constant, and carbon emissions are effectively\u0000controlled. Numerical results demonstrate the effectiveness of the proposed\u0000online method and highlight its advantages over several benchmarks through\u0000comparisons.","PeriodicalId":501286,"journal":{"name":"arXiv - MATH - Optimization and Control","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142212428","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Complexity of Integer Programming in Reverse Convex Sets via Boundary Hyperplane Cover","authors":"Robert Hildebrand, Adrian Göß","doi":"arxiv-2409.05308","DOIUrl":"https://doi.org/arxiv-2409.05308","url":null,"abstract":"We study the complexity of identifying the integer feasibility of reverse\u0000convex sets. We present various settings where the complexity can be either\u0000NP-Hard or efficiently solvable when the dimension is fixed. Of particular\u0000interest is the case of bounded reverse convex constraints with a polyhedral\u0000domain. We introduce a structure, emph{Boundary Hyperplane Cover}, that\u0000permits this problem to be solved in polynomial time in fixed dimension\u0000provided the number of nonlinear reverse convex sets is fixed.","PeriodicalId":501286,"journal":{"name":"arXiv - MATH - Optimization and Control","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142212434","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Tikhonov regularized inertial primal-dual dynamics for convex-concave bilinear saddle point problems","authors":"Xiangkai Sun, Liang He, Xian-Jun Long","doi":"arxiv-2409.05301","DOIUrl":"https://doi.org/arxiv-2409.05301","url":null,"abstract":"In this paper, for a convex-concave bilinear saddle point problem, we propose\u0000a Tikhonov regularized second-order primal-dual dynamical system with slow\u0000damping, extrapolation and general time scaling parameters. Depending on the\u0000vanishing speed of the rescaled regularization parameter (i.e., the product of\u0000Tikhonov regularization parameter and general time scaling parameter), we\u0000analyze the convergence properties of the trajectory generated by the dynamical\u0000system. When the rescaled regularization parameter decreases rapidly to zero,\u0000we obtain convergence rates of the primal-dual gap and velocity vector along\u0000the trajectory generated by the dynamical system. In the case that the rescaled\u0000regularization parameter tends slowly to zero, we show the strong convergence\u0000of the trajectory towards the minimal norm solution of the convex-concave\u0000bilinear saddle point problem. Further, we also present some numerical\u0000experiments to illustrate the theoretical results.","PeriodicalId":501286,"journal":{"name":"arXiv - MATH - Optimization and Control","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142212433","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Omar Rayyan, Vinicius Gonçalves, Nikolaos Evangeliou, Anthony Tzes
{"title":"RCM-Constrained Manipulator Trajectory Tracking Using Differential Kinematics Control","authors":"Omar Rayyan, Vinicius Gonçalves, Nikolaos Evangeliou, Anthony Tzes","doi":"arxiv-2409.05740","DOIUrl":"https://doi.org/arxiv-2409.05740","url":null,"abstract":"This paper proposes an approach for controlling surgical robotic systems,\u0000while complying with the Remote Center of Motion (RCM) constraint in\u0000Robot-Assisted Minimally Invasive Surgery (RA-MIS). In this approach, the\u0000RCM-constraint is upheld algorithmically, providing flexibility in the\u0000positioning of the insertion point and enabling compatibility with a wide range\u0000of general-purpose robots. The paper further investigates the impact of the\u0000tool's insertion ratio on the RCM-error, and introduces a manipulability index\u0000of the robot which considers the RCM-error that it is used to find a starting\u0000configuration. To accurately evaluate the proposed method's trajectory tracking\u0000within an RCM-constrained environment, an electromagnetic tracking system is\u0000employed. The results demonstrate the effectiveness of the proposed method in\u0000addressing the RCM constraint problem in RA-MIS.","PeriodicalId":501286,"journal":{"name":"arXiv - MATH - Optimization and Control","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142212468","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Continuous Relaxation of Discontinuous Shrinkage Operator: Proximal Inclusion and Conversion","authors":"Masahiro Yukawa","doi":"arxiv-2409.05316","DOIUrl":"https://doi.org/arxiv-2409.05316","url":null,"abstract":"We present a principled way of deriving a continuous relaxation of a given\u0000discontinuous shrinkage operator, which is based on a couple of fundamental\u0000results. First, the image of a point with respect to the ``set-valued''\u0000proximity operator of a nonconvex function is included by that for its lower\u0000semicontinuous (l.s.c.) 1-weakly-convex envelope. Second, the ``set-valued''\u0000proximity operator of a proper l.s.c. 1-weakly-convex function is converted,\u0000via double inversion, to a ``single-valued'' proximity operator which is\u0000Lipschitz continuous. As a specific example, we derive a continuous relaxation\u0000of the discontinuous shrinkage operator associated with the reversely ordered\u0000weighted $ell_1$ (ROWL) penalty. Numerical examples demonstrate potential\u0000advantages of the continuous relaxation.","PeriodicalId":501286,"journal":{"name":"arXiv - MATH - Optimization and Control","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142212432","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Bridging Autoencoders and Dynamic Mode Decomposition for Reduced-order Modeling and Control of PDEs","authors":"Priyabrata Saha, Saibal Mukhopadhyay","doi":"arxiv-2409.06101","DOIUrl":"https://doi.org/arxiv-2409.06101","url":null,"abstract":"Modeling and controlling complex spatiotemporal dynamical systems driven by\u0000partial differential equations (PDEs) often necessitate dimensionality\u0000reduction techniques to construct lower-order models for computational\u0000efficiency. This paper explores a deep autoencoding learning method for\u0000reduced-order modeling and control of dynamical systems governed by\u0000spatiotemporal PDEs. We first analytically show that an optimization objective\u0000for learning a linear autoencoding reduced-order model can be formulated to\u0000yield a solution closely resembling the result obtained through the dynamic\u0000mode decomposition with control algorithm. We then extend this linear\u0000autoencoding architecture to a deep autoencoding framework, enabling the\u0000development of a nonlinear reduced-order model. Furthermore, we leverage the\u0000learned reduced-order model to design controllers using stability-constrained\u0000deep neural networks. Numerical experiments are presented to validate the\u0000efficacy of our approach in both modeling and control using the example of a\u0000reaction-diffusion system.","PeriodicalId":501286,"journal":{"name":"arXiv - MATH - Optimization and Control","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142212400","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Charly Robinson La Rocca, Jean-François Cordeau, Emma Frejinger
{"title":"Combining supervised learning and local search for the multicommodity capacitated fixed-charge network design problem","authors":"Charly Robinson La Rocca, Jean-François Cordeau, Emma Frejinger","doi":"arxiv-2409.05720","DOIUrl":"https://doi.org/arxiv-2409.05720","url":null,"abstract":"The multicommodity capacitated fixed-charge network design problem has been\u0000extensively studied in the literature due to its wide range of applications.\u0000Despite the fact that many sophisticated solution methods exist today, finding\u0000high-quality solutions to large-scale instances remains challenging. In this\u0000paper, we explore how a data-driven approach can help improve upon the state of\u0000the art. By leveraging machine learning models, we attempt to reveal patterns\u0000hidden in the data that might be difficult to capture with traditional\u0000optimization methods. For scalability, we propose a prediction method where the\u0000machine learning model is called at the level of each arc of the graph. We take\u0000advantage of off-the-shelf models trained via supervised learning to predict\u0000near-optimal solutions. Our experimental results include an algorithm design\u0000analysis that compares various integration strategies of predictions within\u0000local search algorithms. We benchmark the ML-based approach with respect to the\u0000state-of-the-art heuristic for this problem. The findings indicate that our\u0000method can outperform the leading heuristic on sets of instances sampled from a\u0000uniform distribution.","PeriodicalId":501286,"journal":{"name":"arXiv - MATH - Optimization and Control","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142212409","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"High-Precision Intelligent Reflecting Surfaces-assisted Positioning Service in 5G Networks with Flexible Numerology","authors":"Ti Ti Nguyen, Kim-Khoa Nguyen","doi":"arxiv-2409.05639","DOIUrl":"https://doi.org/arxiv-2409.05639","url":null,"abstract":"Accurate positioning is paramount for a wide array of location-based services\u0000(LBS) in fifth-generation (5G) wireless networks. Recent advances in 5G New\u0000Radio (NR) technology holds promise for very high-precision positioning\u0000services. Yet, challenges arise due to diverse types of numerology and massive\u0000connected devices. This paper presents a novel approach to improve positioning\u0000precision within a 5G NR framework with comb patterns on time-frequency\u0000resource mapping. We then formulate an optimization problem aimed at minimizing\u0000the maximum users' positioning error in an intelligent reflected surface\u0000(IRS)-assisted 5G network by controlling the user-anchor association,\u0000numerology-related selection, IRS's reflecting elements, privacy protection\u0000level, and transmit power. To address the non-convex nature of the underlying\u0000mixed-integer non-convex problem (MINLP), we propose an efficient algorithm\u0000that combines optimization, matching, and learning techniques. Through\u0000extensive numerical experiments, we demonstrate the effectiveness of our\u0000proposed algorithm in minimizing positioning errors compared to conventional\u0000methods.","PeriodicalId":501286,"journal":{"name":"arXiv - MATH - Optimization and Control","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142212427","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}