检索结果-内蒙古大学图书馆

A Two-Phase Approach for Reliability-Redundancy Optimization of a Communication Satellite

GAZI UNIVERSITY JOURNAL OF SCIENCE 2024年第1期37卷 310-324页

作者： Tetik, Taha Das, G. Sena Birgoren, Burak Turkish Aerosp Ankara Turkiye Kirikkale Univ Ind Engn Kirikkale Turkiye

The development and launch of communication satellite projects pose significant challenges and costs. The expenses can range from several hundred million dollars, contingent on factors such as mission objectives, satellite system size and complexity including the launch vehicle, and ground infrastructure. Satellites must be designed to withstand harsh conditions in space, such as the extreme temperatures, radiation, and other hazards, while delivering reliable communication services to its users. However, once a satellite is launched, physical maintenance interventions become infeasible in the event of technical problems. Thus, reliability is a critical aspect for these expensive systems. This study aims to minimize the cost of a high-tech communication satellite by addressing design considerations that meet customer reliability requirements without exceeding power and redundant equipment limits. To achieve this goal, we propose an integer non -linear programming model in this research. To solve the satellite design problem, we adopt a two-stage solution approach. Conventional industrial practices in satellite design often involve iterative attempts to determine the redundancy level of onboard units based on customer reliability requirements. These processes rely heavily on the experience of design engineers who evaluate a limited number of alternatives to determine the number of redundant units, resulting in sub -optimal outcomes. In contrast, our proposed approach systematically handles the problem and yields optimal results. Our findings demonstrate that the proposed two-phase approach can achieve optimal redundancy levels within seconds.

关键词： Communication satellite Reliability optimization Redundancy allocation non-linear programming Integer programming

来源：评论

学校读者我要写书评

暂无评论

An optimization model for planning testing and control strategies to limit the spread of a pandemic-The case of COVID-19

引用

EUROPEAN JOURNAL OF OPERATIONAL RESEARCH 2023年第1期304卷 308-324页

作者： Abdin, Adam F. Fang, Yi-Ping Caunhye, Aakil Alem, Douglas Barros, Anne Zio, Enrico Univ Paris Saclay Lab Genie Ind CentraleSupelec 3 Rue Joliot Curie F-91190 Gif Sur Yvette France Chair Risk & Resilience Complex Syst Gif Sur Yvette France Univ Edinburgh Business Sch Edinburgh Scotland PSL Res Univ Mines ParisTech CRC Sophia Antipolis France Politecn Milan DOE Milan Italy

The global health crisis caused by the coronavirus SARS-CoV-2 has highlighted the importance of effi-cient disease detection and control strategies for minimizing the number of infections and deaths in the population and halting the spread of the pandemic. Countries have shown different preparedness levels for promptly implementing disease detection strategies, via mass testing and isolation of identified cases, which led to a largely varying impact of the outbreak on the populations and health-care systems. In this paper, we propose a new pandemic resource allocation model for allocating limited disease detection and control resources, in particular testing capacities, in order to limit the spread of a pandemic. The pro-posed model is a novel epidemiological compartmental model formulated as a non-linear programming model that is suitable to address the inherent non-linearity of an infectious disease progression within the population. A number of novel features are implemented in the model to take into account impor-tant disease characteristics, such as asymptomatic infection and the distinct risk levels of infection within different segments of the population. Moreover, a method is proposed to estimate the vulnerability level of the different communities impacted by the pandemic and to explicitly consider equity in the resource allocation problem. The model is validated against real data for a case study of COVID-19 outbreak in France and our results provide various insights on the optimal testing intervention time and level, and the impact of the optimal allocation of testing resources on the spread of the disease among regions. The results confirm the significance of the proposed modeling framework for informing policymakers on the best preparedness strategies against future infectious disease outbreaks.(c) 2021 Elsevier B.V. All rights reserved.

关键词： (S) decision support systems Pandemic control COVID-19 Disaster preparedness non-linear programming

来源：评论

学校读者我要写书评

暂无评论

Joint UAV deployment, SF placement, and collaborative task scheduling in heterogeneous multi-UAV-empowered edge intelligence

引用

IET COMMUNICATIONS 2023年第5期17卷 641-657页

作者： Wang, Yangang Wei, Xianglin Wang, Hai Fan, Jianhua Chen, Juan Zhao, Kuang Hu, Yongyang Army Engn Univ PLA Coll Commun Engn Nanjing Peoples R China Natl Univ Def Technol Res Inst 63 Nanjing Peoples R China

To support artificial intelligence (AI)-involved tasks offloaded from the mobile devices (MDs), it is necessary to equip the Unmanned Aerial Vehicle (UAV) with custom-made co-processor (CP) for handling AI workloads in multi-UAV-empowered Edge Intelligence. Existing CPU-oriented task scheduling algorithm cannot apply to the CPU+CP heterogeneous architecture. In this backdrop, this paper first formulates the joint service function placement, collaborative task scheduling, UAV deployment, and MD position determination problem as a Mixed Integer non-linear programming problem. Then, an alternating optimization-based algorithm is put forward to derive a sub-optimal solution of the problem utilizing Differential Evolution and Greedy-based Hungarian algorithms. A series of experiments are conducted to evaluate the performance of the proposal. Results show that authors' proposal can achieve an overall revenue that is roughly 50% higher than those of existing methods.

关键词： decision making iterative methods mobile computing non-linear programming

来源：评论

学校读者我要写书评

暂无评论

Influence of Load Modeling on the Cost of Ensuring Stability Using TSCOPF

引用

IEEE ACCESS 2023年 11卷 133329-133339页

作者： Arredondo, Francisco Rachmanidis, Michail Ledesma, Pablo Castronuovo, Edgardo D. Aghahassani, Mohammadamin Univ Carlos III Madrid Dept Ingn Elect Leganes 28911 Spain Natl Tech Univ Athens DSS Lab EPU NTUA Athens 15773 Greece Univ Politecn Cataluna CITCEA UPC Barcelona 08028 Spain

Load modeling significantly impacts the time-domain response of power systems in transient stability studies but this effect is often underestimated in Transient Stability Constrained Optimal Power flow (TSCOPF) studies. The object of this study is twofold: 1) it proposes a robust formulation based on a relevant node representation approach that allows the use of any type of load model in TSCOPF algorithms, while maintaining the accuracy and reducing the size of a full representation approach;and 2) it conducts a comparative analysis of how load modeling influences the cost of ensuring stability and provides a summary of several recommendations for load modeling in these algorithms. The results show that the usual approach in TSCOPF studies, which involves impedance-based load modeling, leads to a significant false stabilization effect in the rotor angle trajectories. On the other hand, the use of the constant power model yields conservative results at a significant computational cost. This paper advocates for the adoption of the relevant node TSCOPF approach proposed in this work, retaining detailed exponential or polynomial load models for their flexibility and accuracy, while incurring only a slight increase in the computational effort.

关键词： Load modeling Power system stability Power generation Mathematical models Transient analysis Computational modeling Stability criteria non-linear programming optimal power flow power system transient stability TSCOPF

来源：评论

学校读者我要写书评

暂无评论

Numerical Strategies for Mixed-Integer Optimization of Power-Split and Gear Selection in Hybrid Electric Vehicles

引用

IEEE TRANSACTIONS ON INTELLIGENT TRANSPORTATION SYSTEMS 2023年第3期24卷 3194-3210页

作者： Ganesan, Anand Gros, Sebastien Murgovski, Nikolce Volvo Car Corp Res & Dev S-40531 Gothenburg Sweden Chalmers Univ Technol Dept Elect Engn S-41296 Gothenburg Sweden Norwegian Univ Sci & Technol Dept Engn Cybernet N-7491 Trondheim Norway

This paper presents numerical strategies for a computationally efficient energy management system that co-optimizes the power split and gear selection of a hybrid electric vehicle (HEV). We formulate a mixed-integer optimal control problem (MIOCP) that is transcribed using multiple-shooting into a mixed-integer nonlinear program (MINLP) and then solved by nonlinear model predictive control. We present two different numerical strategies, a Selective Relaxation Approach (SRA), which decomposes the MINLP into several subproblems, and a Round-n-Search Approach (RSA), which is an enhancement of the known "relax-n-round' strategy. Subsequently, the resulting algorithmic performance and optimality of the solution of the proposed strategies are analyzed against two benchmark strate-gies;one using rule-based gear selection, which is typically used in production vehicles, and the other using dynamic programming (DP), which provides a global optimum of a quantized version of the MINLP. The results show that both SRA and RSA enable about 3.6% cost reduction compared to the rule-based strategy, while still being within 1% of the DP solution. Moreover, for the case studied RSA takes about 35% less mean computation time compared to SRA, while both SRA and RSA being about 99 times faster than DP. Furthermore, both SRA and RSA were able to overcome the infeasibilities encountered by a typical rounding strategy under different drive cycles. The results show the computational benefit of the proposed strategies, as well as the energy saving possibility of co-optimization strategies in which actuator dynamics are explicitly included.

关键词： Mixed-Integer nonlinear optimal control non-linear programming numerical optimization hybrid electric vehicle energy management nonlinear MPC optimal torque-split optimal gear selection

来源：评论

学校读者我要写书评

暂无评论

Minimum-Race-Time Energy Allocation Strategies for the Hybrid-Electric Formula 1 Power Unit

引用

IEEE TRANSACTIONS ON VEHICULAR TECHNOLOGY 2023年第6期72卷 7035-7050页

作者： Duhr, Pol Buccheri, Daniele Balerna, Camillo Cerofolini, Alberto Onder, Christopher H. Swiss Fed Inst Technol Inst Dynam Syst & Control CH-8092 Zurich Switzerland Ferrari SpA Performance & Control Grp Power Unit I-41053 Maranello Italy

The hybrid-electric powertrain currently used in Formula 1 race cars draws its energy from the car's fuel tank and battery. The usable battery size is limited, and refueling during a race is forbidden by the regulations of the Formula 1 race series. From a strategic point of view, lap-by-lap targets for the fuel and battery consumption must be chosen and imposed on the energy management controller of the car. This task is non-trivial dueto the influence of the on-board fuel mass on the achievable lap time, as well as the cross-couplings between the electric and the combustion part of the powertrain. A systematic approach is thus required to compute the energy allocation strategy that minimizes the total race time. In this paper, we devise an optimization framework in the form of a non-linear program, yielding the optimal battery and fuel consumption targets for each lap of the race. The approach is based on maps that capture the achievable lap time as a function of car mass and allocated battery and fuel energy. These maps are generated beforehand with a model-based single-lap optimization framework and fitted using artificial neural network techniques. To showcase the approach, we present three case studies: First, we compare the optimal strategy to a heuristic method. The im-provement of 2 s over the entire race is substantial, given that the difference only lies in the energy allocation, but not in the overall consumption. It underlines the importance of optimizing the energy allocation. Second, we leverage the framework to compute the optimal fuel load at the beginning of the race. Finally, we apply the developed non-linear program in a shrinking-horizon fashion. Our simulation results show that the resulting model predictive controller correctly reacts to disturbances that frequently occur during a race.

关键词： Energy management Formula 1 hybrid electric artificial neural networks non-linear programming

来源：评论

学校读者我要写书评

暂无评论

Prediction of Uncertain Parameters of a Sustainable Supply Chain Using an Artificial Intelligence Approach

引用

Operations Research Forum 2025年第1期6卷 1-25页

作者： Nazari, Massoumeh Dehghan Nayeri, Mahmoud Fathi Hafshjani, Kiamars Department of Industrial Management Islamic Azad University Tehran South Branch Management Faculty Damavand Tehran Tehran *** Iran Department of Industrial Management Tarbiat Modares University Management and Economics Faculty Jalale El Ahmad Nasr Bridge Tehran Tehran 14115111 Iran

Automotive companies have a stable supply chain due to extensive vehicle production and global supply networks. The purpose of sustainable supply chain intelligence in this study is to minimize system costs and environmental pollution. This study is descriptive-analytical, and transportation costs, which have a significant role in environmental pollution, were considered the main parameter, using time series forecasting by Narnet. The results showed significant differences between the predicted shipping costs from the supplier to the factory, from the factory to the distributor, from the distributor to the customer, from the customer to recycling, and from recycling back to the factory. The findings show artificial intelligence in the sustainable automotive supply chain can improve efficiency, reduce resource waste, enhance risk management, and maintain the sustainability of the supply chain. © The Author(s), under exclusive licence to Springer Nature Switzerland AG 2024.

关键词： Artificial intelligence non-linear programming Sustainable supply chain Uncertainty

来源：评论

学校读者我要写书评

暂无评论

EFFICIENT VISUAL QUESTION ANSWERING ON EMBEDDED DEVICES: CROSS-MODALITY ATTENTION WITH EVOLUTIONARY QUANTIZATION 31

EFFICIENT VISUAL QUESTION ANSWERING ON EMBEDDED DEVICES: CRO...

引用

2024 International Conference on Image Processing

作者： Mishra, Aakansha Agarwala, Aditya Tiwari, Utsav Rajendiran, Vikram N. Miriyala, Srinivas S. Samsung Res Inst Bangalore Bangalore Karnataka India

ISBN: (纸本)9798350349405;9798350349399

Visual Question Answering (VQA) lies at the intersection of vision and language domains necessitating learning representations from multiple modalities. While the model development for VQA has witnessed tremendous growth, the efforts for its deployment on embedded devices have been lagging limiting its true potential. In this work, the authors address this challenge by designing a novel hardware- friendly architecture for VQA based on the transformer model with cross-modality attention. The memory footprint of the VQA model is optimized for on-device deployment using a distributed framework for Post Training Quantization (PTQ) formulated as a non-linear programming (NLP) problem. The NLP problem is solved using an Evolutionary algorithm to determine the low-bit representation of the VQA model with minimal accuracy drop compared to the full precision model. The quantized model for VQA with a marginal accuracy drop of less than 2%, resulted in 4 times memory improvement, and over 2 times latency improvement, enabling its successful deployment on the Samsung Galaxy S23 device. The comprehensive study explores the potential of the proposed generic end-to-end pipeline from VQA model development to its deployment.

关键词： Visual Question Answering Cross-Modality Attention Post Training Quantization non-linear programming Evolutionary Algorithms Model Deployment

来源：评论

学校读者我要写书评

暂无评论

The impact of Ilisu Dam on water flow toward Iraq and identifying the optimal operational strategy for Mosul Dam

引用

SUSTAINABLE WATER RESOURCES MANAGEMENT 2023年第4期9卷 112页

作者： Agha, Omar M. A. Mahmood Khattab, Mohammed A. Univ Mosul Coll Engn Dept Dams & Water Resources Mosul Iraq

The primary aim of this research is to investigate the impact of dams constructed in Turkey on the operational policy of the Mosul Dam. The study employs non-linear programming to establish an optimization model for the Mosul Dam reservoir, with the goal of maximizing hydropower generation and determining the optimal operation policy. Statistical tests, including Kendall's Rank Correlation Test and the Standard Normal Homogeneity Test, were used to analyze the direction and identify change points in the time-series. The results indicate a significant decrease in flow during March, April, and May due to dam construction in Turkey, with quantities ranging from 37.8 to 79 MCM/year for the total period. Conversely, there was a significant increase in flow during August and September due to hydroelectric power generation in the summer, with quantities of 20.6 and 15.5 MCM/year, respectively. Additionally, applying the non-linear optimization model to the last 2 years (2019-2020) and (2020-2021) revealed an increase in hydroelectric power production (220 and 180 MW, respectively) compared to actual hydropower generated (2067 and 2155 MW, respectively), as management did not realize the impact of Ilisu Dam on inflows. At the same time, the hydropower created during these 2 years fell short of the average hydropower generated throughout the entire period, which was 3367 MW. Also, the strength and efficiency of the non-linear optimization model and the possibility of employing it in identifying the operational policy when inflow is relatively low were proved.

关键词： Mosul Dam Ilisu Dam Optimal operational Kendall's rank correlation non-linear programming

来源：评论

学校读者我要写书评

暂无评论

Some properties and applications of (v, w)-convex functions

引用

OPSEARCH 2025年 1-15页

作者： Akhter, Ehtesham Ali, Musavvir Aligarh Muslim Univ Dept Math Aligarh 202002 Uttar Pradesh India

This paper builds on the work of Bessem Samet by introducing new results in the context of (v, w)-convex functions, both in general and for differentiable cases. The study extends the definition of (v, w)-convex functions from Euclidean space to Riemannian manifolds, leading to the concept of geodesic (v, w)-convex functions. Several theorems are proven, including results that show the preservation of (v, w)-convexity under summation and positive scalar multiplication of functions. Additionally, the paper presents novel findings on (v, w)-convexity in Riemannian manifolds, providing a theoretical foundation for future exploration. The developed theorems are also applied to nonlinear programming, offering a method to find optimal solutions for differentiable functions within this framework. This research contributes to both the theory of convexity and its applications in optimization problems on Riemannian manifolds.

关键词： (v w)-convex functions Geodesic (v w)-convex non-linear programming Optimization

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

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

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：