检索结果-内蒙古大学图书馆

Efficient Parasitic-aware gm/ID-based Hybrid Sizing Methodology for Analog and RF Integrated Circuits

ACM TRANSACTIONS ON DESIGN AUTOMATION OF ELECTRONIC SYSTEMS 2021年第2期26卷 1-31页

作者： Liao, Tuotian Zhang, Lihong Mem Univ Newfoundland Fac Engn & Appl Sci Dept Elect & Comp Engn St John NF A1B 3X5 Canada

As the primary second-order effect, parasitic issues have to be seriously addressed when synthesizing high-performance analog and RF integrated circuits (ICs). In this article, a two-phase hybrid sizing methodology for analog and RF ICs is proposed to take into account parasitic effect in the early design stage. It involves symbolic modeling and mixed-integer nonlinear programming (MINLP) in the first phase, and a many-objective evolutionary algorithm (many-OEA)-based sizing refiner in the second phase. With the aid of our proposed current density factor and piecewise curve fitting technique, the g(m)/I-D concept, which is typically utilized to solve the analog circuit design problem, can provide theoretical support to our accurate symbolic modeling. Thus, the intrinsic and interconnect parasitics can be accurately considered in our work with moderate modeling effort. A variety of electrical, geometric, and parasitic (including parasitic mismatch) constraints can be conveniently integrated into our MINLP problem formulation. Moreover, numerical simulations are embedded into the many-OEA-based sizing phase, which is able to tackle floorplan co-optimization. With such dynamic floorplan variation, the parasitics accuracy can be sustained along the evolution. The experimental results demonstrate high efficacy of our proposed parasitic-aware hybrid sizing methodology.

关键词： Analog and RF ICs circuit sizing circuit modeling floorplan optimization g(m)/I-D many-objective evolutionary algorithm mixed-integer nonlinear programming parasitic modeling

来源：评论

学校读者我要写书评

暂无评论

Optimal Power Flow Problem Solution Through a Matheuristic Approach

引用

IEEE ACCESS 2021年 9卷 84576-84587页

作者： Home-Ortiz, Juan M. Claro De Oliveira, Wmerson Sanches Mantovani, Jose Roberto Sao Paulo State Univ Dept Elect Engn BR-15385000 Ilha Solteira Brazil

The optimal power flow (OPF) problem is a widely studied subject in the literature that has been solved through classical and metaheuristic optimization techniques. Nowadays, significant advances in computational resources and commercial optimization solvers allow solving complex optimization problems by combining the best of both worlds in approaches that are known as matheuristics, however, in order to solve the OPF problem, matheuristic approaches have been little explored. In this regard, this paper presents a novel Variable Neighborhood Descent (VND) matheuristic approach to solve the OPF problem for large-scale systems. The proposed algorithm combines the classic OPF model and the VND heuristic algorithm. The OPF problem is formulated as a mixed-integer nonlinear programming (MINLP) model, in which the objective function aims to minimize the fuel generation costs, subject to the physical and operational constraints of the power system. The integer variables of this MINLP model represent the control of taps positions of the on-load tap changers and the reactive shunt compensation equipment. To validate the proposed methodology, 17 power systems of specialized literature were tested with sizes from 14 to 4661 buses, and the obtained solutions are compared with the solutions provided by the commercial optimization solver Knitro. Results show the superiority of the proposed matheuristic algorithm compared with Knitro to solve the MINLP-OPF model for large-scale systems.

关键词： Matheuristic optimization mixed-integer nonlinear programming optimal power flow variable neighborhood search

来源：评论

学校读者我要写书评

暂无评论

A Novel Approximation of Security-Constrained Optimal Power Flow With Incorporation of Generator Frequency and Voltage Control Response

引用

IEEE TRANSACTIONS ON POWER SYSTEMS 2021年第3期36卷 2438-2447页

作者： Avramidis, Iason-Iraklis Capitanescu, Florin Karagiannopoulos, Stavros Vrettos, Evangelos Luxembourg Inst Sci & Technol LIST L-4422 Belvaux Luxembourg Swissgrid CH-5001 Aarau Switzerland

This paper tackles key industry needs in the scope of the AC Security-Constrained Optimal Power Flow (SCOPF) framework, specifically two major challenging requirements regarding generators' post-contingency behavior: the (droop-based) frequency response and the voltage control mechanism (including PV/PQ switching). To this end, and to obtain a sufficiently accurate solution with a reasonable computational burden, we propose an approximation approach to SCOPF which extends significantly an existing algorithm with novel modelling elements: a continuous formulation to model generators' post-contingency responses based on successive approximations, a technique to evaluate the viability of contingencies with respect to the base case set-points, and the complexity reduction of all post-contingency states through network compression and power flow piecewise linearization. All new features are validated both separately and in unison, to monitor the improvement of the solution time and the potential degradation of the solution's quality. The proposed approach is successfully applied to three power system network models, the largest of which consists of 2,000 buses and more than 3,000 contingencies. Finally, the trade-off between the limitations in terms of solution quality and the benefits in terms of computational effort are assessed for all proposed approximations.

关键词： Generators Reactive power Voltage control Mathematical model Switches Computational modeling Frequency control Contingency filtering generator contingency response mixed-integer nonlinear programming network compression security-constrained optimal power flow

来源：评论

学校读者我要写书评

暂无评论

Inversion of convection-diffusion equation with discrete sources

引用

OPTIMIZATION AND ENGINEERING 2021年第3期22卷 1419-1457页

作者： Sharma, Meenarli Hahn, Mirko Leyffer, Sven Ruthotto, Lars Waanders, Bart van Bloemen Indian Inst Technol Powai 400076 Maharashtra India Otto von Guericke Univ Univ Pl 2 Magdeburg Germany Argonne Natl Lab 9700 South Cass Ave Lemont IL 50439 USA Emory Univ 400 Dowman Dr Atlanta GA 30322 USA Sandia Natl Labs POB 5800 Albuquerque NM 87185 USA

We present a convection-diffusion inverse problem that aims to identify an unknown number of sources and their locations. We model the sources using a binary function, and we show that the inverse problem can be formulated as a large-scale mixed-integer nonlinear optimization problem. We show empirically that current state-of-the-art mixed-integer solvers cannot solve this problem and that applying simple rounding heuristics to solutions of the relaxed problem can fail to identify the correct number and location of the sources. We develop two new rounding heuristics that exploit the value and a physical interpretation of the continuous relaxation solution, and we apply a steepest-descent improvement heuristic to obtain satisfactory solutions to both two- and three-dimensional inverse problems. We also provide the code used in our numerical experiments in open-source format.

关键词： mixed-integer optimization PDE-constrained optimization mixed-integer nonlinear programming Source inversion

来源：评论

学校读者我要写书评

暂无评论

Solving mixed-integer nonlinear optimization problems using simultaneous convexification: a case study for gas networks

引用

JOURNAL OF GLOBAL OPTIMIZATION 2021年第2期80卷 307-340页

作者： Liers, Frauke Martin, Alexander Merkert, Maximilian Mertens, Nick Michaels, Dennis Friedrich Alexander Univ Erlangen Nurnberg Dept Math Cauerstr 11 D-91058 Erlangen Germany Otto von Guericke Univ Dept Math Univ Pl 2 D-39106 Magdeburg Germany Tech Univ Dortmund Fac Math Dortmund Germany

Solving mixed-integer nonlinear optimization problems (MINLPs) to global optimality is extremely challenging. An important step for enabling their solution consists in the design of convex relaxations of the feasible set. Known solution approaches based on spatial branch-and-bound become more effective the tighter the used relaxations are. Relaxations are commonly established by convex underestimators, where each constraint function is considered separately. Instead, a considerably tighter relaxation can be found via so-called simultaneous convexification, where convex underestimators are derived for more than one constraint function at a time. In this work, we present a global solution approach for solving mixed-integer nonlinear problems that uses simultaneous convexification. We introduce a separation method that relies on determining the convex envelope of linear combinations of the constraint functions and on solving a nonsmooth convex problem. In particular, we apply the method to quadratic absolute value functions and derive their convex envelopes. The practicality of the proposed solution approach is demonstrated on several test instances from gas network optimization, where the method outperforms standard approaches that use separate convex relaxations.

关键词： mixed-integer nonlinear programming Simultaneous convexification Convex envelope Gas network optimization

来源：评论

学校读者我要写书评

暂无评论

Bi-Objective Job-Shop Scheduling Considering Human Fatigue in Cobotic Order Picking Systems: A Case of an Online Grocer

引用

Procedia Computer Science 2024年 232卷 635-644页

作者： Berry Lance Vermin David Abbink Frederik Schulte Department of Cognitive Robotics Delft University of Technology Mekelweg 2 2628 CD Delft The Netherlands Department of Maritime & Transport Technology Mekelweg 2 2628 CD Delft The Netherlands

Increasing online retail has resulted in increased automation in order picking systems, leading to new challenges and opportunities in task scheduling. The job-shop scheduling problem is an optimization problem essential in such systems, but existing JSP literature often overlooks workplace fatigue, which harms employees’ well-being and costs U.S. employers up to €127 billion annually. In this work, we propose fatigue consideration in the job-shop scheduling problem in a cobotic order picking system to mitigate its negative effects. We present a new bi-objective mixed integer nonlinear programming problem formulation that considers worker fatigue and productivity during schedule optimisation. To put the results of simulated optimisation in perspective, we experimentally validate the fatigue model and scheduling results in a real operation. The mathematical model finds solutions that conventional single-objective optimisation cannot, allowing fractional fatigue distribution improvements more than 4x larger than the decrease in productivity they require in 53% of the considered virtual cases. The experiments show that our predictive fatigue model has an average RMSE of 2.20 kcal/min in estimating energy expenditure rates compared to heart rate measurements. It also shows a low correlation, meaning it is unfit for application. On the other hand, fatigue-conscious schedules show no clear benefit regarding measured and perceived fatigue. However, the scheduling model could also use heart rate measurements that do not show these inaccuracies. Our study highlights the need to further develop and validate the mathematical formulation and fatigue model and extend to other human factors and indirect fatigue effects.

关键词： Order Picking Job-Shop Scheduling Problem Human Factors mixed-integer nonlinear programming Occupational Fatigue Cobotic Order Picking

来源：评论

学校读者我要写书评

暂无评论

Lift-and-project cuts for convex mixed integer nonlinear programs Linear programming based separation and extended formulations

引用

MATHEMATICAL programming COMPUTATION 2017年第4期9卷 499-526页

作者： Kilinc, Mustafa R. Linderoth, Jeff Luedtke, James Carnegie Mellon Univ Dept Chem Engn Pittsburgh PA 15213 USA Univ Wisconsin Wisconsin Inst Discovery Dept Ind & Syst Engn Madison WI USA

We describe a computationally effective method for generating lift-andproject cuts for convex mixed-integer nonlinear programs (MINLPs). The method relies on solving a sequence of cut-generating linear programs and in the limit generates an inequality as strong as the lift-and-project cut that can be obtained from solving a cut-generating nonlinear program. Using this procedure, we are able to approximately optimize over the rank one lift-and-project closure for a variety of convex MINLP instances. The results indicate that lift-and-project cuts have the potential to close a significant portion of the integrality gap for convex MINLPs. In addition, we find that using this procedure within a branch-and-cut solver for convex MINLPs significantly reduces the total solution time for many instances. We also demonstrate that combining lift-and-project cuts with an extended formulation that exploits separability of convex functions yields significant improvements in both relaxation bounds and the time to calculate the relaxation. Overall, these results suggest that with an effective separation routine, like the one proposed here, lift-and-project cuts may be as effective for solving convex MINLPs as they have been for solving mixed-integer linear programs.

关键词： Lift-and-project cuts Extended formulations mixed-integer nonlinear programming

来源：评论

学校读者我要写书评

暂无评论

The Location Routing Problem of the Car-Sharing System with Autonomous Electric Vehicles

引用

KSCE JOURNAL OF CIVIL ENGINEERING 2021年第8期25卷 3107-3120页

作者： Ma, Bingshan Hu, Dawei Wu, Xue Changan Univ Sch Automobile Xian 710064 Peoples R China Changan Univ Sch Transportat Engn Xian 710064 Peoples R China

Car-sharing, electrification, and autonomous driving are greatly revolutionizing the future of the transportation system. This study proposes a location routing problem for the car-sharing system with autonomous electric vehicles to determine optimal station location and vehicle routing, where each station is both a depot and a charging station. A mathematical model is formulated and then extended to three variants, while simultaneously considering different recharging and service options. The proposed mixed-integer nonlinear models are separately solved by general algebraic modeling system (GAMS) and genetic algorithm (GA), and the efficiency of the GA is demonstrated. The comparative experimental results of instances are presented, and the benefits of allowing partial recharge are obtained. More significant savings in cost can be achieved if partial service is simultaneously allowed. Furthermore, the trade-off between the operator's interests and the interests of users, as well as the operator's immediate profits and future profits, are explored through sensitivity analysis.

关键词： Shared autonomous vehicles Electric vehicles Location routing problem mixed-integer nonlinear programming Genetic algorithm (GA)

来源：评论

学校读者我要写书评

暂无评论

Additive manufacturing capacity allocation problem over a network

引用

IISE TRANSACTIONS 2023年第8期55卷 807-820页

作者： Cokyasar, Taner Jin, Mingzhou Univ Tennessee Dept Ind & Syst Engn Knoxville TN 37996 USA Argonne Natl Lab Transportat & Power Syst Div Lemont IL USA Tarsus Univ Dept Ind Engn Takbas Mersin Turkey

The use of Additive Manufacturing (AM) for low demand volumes, such as spare parts, has recently attracted considerable attention from researchers and practitioners. This study defines the AM Capacity Allocation Problem (AMCAP) to design an AM supply network and choose between printing upon demand and sourcing through an alternative option for each part in a given set. A mixed-integer nonlinear program was developed to minimize the production, transportation, alternative sourcing, and lead time costs. We developed a cut generation algorithm to find optimal solutions in finite iterations by exploring the convexity of the nonlinear waiting time for AM products at each AM facility. Numerical experiments show the effectiveness of the proposed algorithm for the AMCAP. A case study was conducted to demonstrate that the optimal AM deployment can save almost 20% of costs over situations that do not use any AM. The case also shows that AM can realize its maximum benefits when it works in conjunction with an alternative option, e.g., inventory holding, and its capacity is strategically deployed. Since AM is a new technology and is rapidly evolving, this study includes a sensitivity analysis to see the effects of improved AM technology features, such as machine cost and build speed. When the build speed increases, the total cost decreases quickly, but the number of AM machines will increase first then decrease later when more parts are assigned to the AM option.

关键词： Additive manufacturing capacity planning network optimization mixed-integer nonlinear programming

来源：评论

学校读者我要写书评

暂无评论

Optimal voyage scheduling of all-electric ships considering underwater radiated noise

引用

TRANSPORTATION RESEARCH PART C-EMERGING TECHNOLOGIES 2023年第1期148卷

作者： Khatami, Roohallah Chen, Bo Chen, Yu Christine Univ British Columbia Dept Elect & Comp Engn Vancouver BC Canada

Underwater radiated noise (URN) emanating from ships can adversely impact the life functions of certain marine mammals that rely on sound to navigate, communicate, and locate prey. This paper formulates an optimal voyage scheduling problem to mitigate the impact of URN on sensitive marine species by choosing amongst different possible paths and specifying the cruising speed along the selected path. We focus on all-electric ships (AESs) owing to their greater flexibility for speed regulation by coordinating an integrated power system. The proposed optimization model schedules generators and energy storage devices toward minimizing the operation cost while satisfying constraints pertinent to URN levels and atmospheric greenhouse gas (GHG) emissions, the electric power network and operational limits, and expected voyage timelines, culminating in a mixed-integer nonlinear programming problem. To promote com-putational tractability, we approximate the nonlinear relationships for URN, propulsion load, and fuel consumption with piecewise linear functions. This leads to a mixed-integer second -order cone programming problem, which enables convergence to the global optimum and computationally efficient solutions. We illustrate the effectiveness of the proposed model in curbing URN levels and GHG emissions with numerical case studies involving an 18-node ship test system.

关键词： All-electric ship mixed-integer nonlinear programming Optimal voyage scheduling Underwater radiated noise

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：