检索结果-内蒙古大学图书馆

On the Location of Fog Nodes in Fog-Cloud Infrastructures

SENSORS 2019年第11期19卷 2445.-2445.页

作者： da Silva, Rodrigo A. C. da Fonseca, Nelson L. S. Univ Estadual Campinas UNICAMP IC Av Albert Einstein 1251 BR-13083852 Campinas SP Brazil

In the fog computing paradigm, fog nodes are placed on the network edge to meet end-user demands with low latency, providing the possibility of new applications. Although the role of the cloud remains unchanged, a new network infrastructure for fog nodes must be created. The design of such an infrastructure must consider user mobility, which causes variations in workload demand over time in different regions. Properly deciding on the location of fog nodes is important to reduce the costs associated with their deployment and maintenance. To meet these demands, this paper discusses the problem of locating fog nodes and proposes a solution which considers time-varying demands, with two classes of workload in terms of latency. The solution was modeled as a mixed-integer linear programming formulation with multiple criteria. An evaluation with real data showed that an improvement in end-user service can be obtained in conjunction with the minimization of the costs by deploying fewer servers in the infrastructure. Furthermore, results show that costs can be further reduced if a limited blocking of requests is tolerated.

关键词： fog computing cloud computing facility location mixed-integer linear programming

来源：评论

学校读者我要写书评

暂无评论

Stochastic maximum flow interdiction problems under heterogeneous risk preferences

引用

COMPUTERS & OPERATIONS RESEARCH 2018年 90卷 97-109页

作者： Lei, Xiao Shen, Siqian Song, Yongjia Univ Int Business & Econ Beijing Peoples R China Univ Michigan Dept Ind & Operat Engn Ann Arbor MI 48109 USA Virginia Commonwealth Univ Dept Stat Sci & Operat Res Richmond VA USA

We consider a generic maximum flow interdiction problem that involves a leader and a follower who take actions in sequence. Given an interdiction budget, the leader destroys a subset of arcs to minimize the follower's maximum flows from a source to a sink node. The effect from an interdiction action taken on each arc is random, following a given success rate of decreasing the arc's capacity to zero. The follower can add additional arc capacities for mitigating flow losses, after knowing the leader's interdiction plan but before realizing the uncertainty. We consider risk-neutral and risk-averse behaviors of the two players and investigate five bi-level/tri-level programming models for different risk-preference combinations. The models incorporate the expectation, left-tail, and right-tail Conditional Value-at-Risk (CVaR) as commonly used convex risk measures for evaluating random maximum flows in the leader's and follower's objectives. We reformulate each model as an equivalent mixed-integer linear program and test them on real-world network instances to demonstrate interactions between the leader and the follower under various risk-preference settings. (c) 2017 Elsevier Ltd. All rights reserved.

关键词： Maximum flow interdiction Stochastic programming Conditional value-at-Risk (CVar) Risk-averse optimization mixed-integer linear programming

来源：评论

学校读者我要写书评

暂无评论

Coordinated platooning with multiple speeds

引用

TRANSPORTATION RESEARCH PART C-EMERGING TECHNOLOGIES 2018年 90卷 213-225页

作者： Luo, Fengqiao Larson, Jeffrey Munson, Todd Northwestern Univ Dept Ind Engn & Management Sci Evanston IL 60202 USA Argonne Natl Lab Div Math & Comp Sci Lemont IL 60439 USA

In a platoon, vehicles travel one after another with small intervehicle distances;trailing vehicles in a platoon save fuel because they experience less aerodynamic drag. This work presents a coordinated platooning model with multiple speed options that integrates scheduling, routing, speed selection, and platoon formation/dissolution in a mixed-integer linear program that minimizes the total fuel consumed by a set of vehicles while traveling between their respective origins and destinations. The performance of this model is numerically tested on a grid network and the Chicago-area highway network. We find that the fuel-savings factor of a multivehicle system significantly depends on the time each vehicle is allowed to stay in the network;this time affects vehicles' available speed choices, possible routes, and the amount of time for coordinating platoon formation. For problem instances with a large number of vehicles, we propose and test a heuristic decomposed approach that applies a clustering algorithm to partition the set of vehicles and then routes each group separately. When the set of vehicles is large and the available computational time is small, the decomposed approach finds significantly better solutions than does the full model.

关键词： Vehicle platooning routing Optimization modeling mixed-integer linear programming

来源：评论

学校读者我要写书评

暂无评论

Advanced control strategy for an energy storage system in a grid-connected microgrid with renewable energy generation

引用

IET SMART GRID 2018年第3期1卷 96-103页

作者： Teo, Tiong Teck Logenthiran, Thillainathan Woo, Wai Lok Abidi, Khalid Newcastle Univ Sch Elect & Elect Engn Newcastle Upon Tyne NE1 7RU Tyne & Wear England

The operating cost of the consumer can be reduced in an electricity market-based environment by shifting consumption to a lower price period. This study presents the design of an advanced control strategy to be embedded in a grid connected microgrid with renewable and energy storage capability. The objectives of the control strategy are to control the charging and discharging rates of the energy storage system to reduce the end-user operating cost through arbitrage operation of the energy storage system and to reduce the power exchange between the main and microgrid. Instead of using a forecasting-based approach, the proposed methodology takes the difference between the available renewable generation and load, state-of-charge of energy storage system and electricity market price to determine the charging and discharging rates of the energy storage system in a rolling horizon. The proposed control strategy is compared with a self-adaptive energy storage system controller and mixed-integer linear programming with the same objectives. Empirical evidence shows that the proposed controller can achieve a lower operating cost and reduce the power exchange between the main and microgrid.

关键词： pricing linear programming renewable energy sources energy storage distributed power generation integer programming power grids power markets power generation control adaptive control advanced control strategy grid-connected microgrid renewable energy generation renewable energy storage capability charging discharging rates mixed-integer linear programming electricity market price forecasting-based approach power exchange end-user operating cost reduction discharging rates electricity market-based environment self-adaptive energy storage system controller B0260 Optimisation techniques B8110B Power system management, operation and economics C1180 Optimisation techniques C1340E Self-adjusting control systems C3340H Control of electric power systems B8120K Distributed power generation

来源：评论

学校读者我要写书评

暂无评论

Distributed biomass supply chain cost optimization to evaluate multiple feedstocks for a biorefinery

引用

APPLIED ENERGY 2019年 254卷 113660-000页

作者： Roni, Mohammad S. Thompson, David N. Hartley, Damon S. Idaho Natl Lab Data & Software Sci Idaho Falls ID 83402 USA Idaho Natl Lab Bioenergy Technol Dept Idaho Falls ID USA

Conventional practices of siting all biomass preprocessing operations at the biorefinery is widely believed to be the most cost-effective solution for feedstock supply because of economies of scale. However, biomass preprocessing operations could be decentralized by moving the preprocessing operations to distributed biomass preprocessing centers, also known as "depots" located near biomass sources. This study presents a comparative case study with multiple biomass resources to analyze biorefinery feedstock supply logistics designs having distributed depots and a primary depot co-located with the biorefinery. A mixed-integer linear programming model was developed to simultaneously optimize feedstock sourcing decisions, and optimal preprocessing depot locations and size, utilizing biomass resources from agricultural residue, energy and municipal solid waste to meet carbohydrate specifications and feedstock demand for a biochemical conversion process. Results from a case study in the US showed that a biorefinery could increase its feedstock supply draw area and supply volume by 57.3%, 177.4% respectively without increasing the feedstock delivered cost by adopting distributed depot-in the feedstock supply chain design. A distributed-depot-based supply chain can be more economical by selecting optimal mix of biomass resource, optimal siting and depot scales during feedstock supply chain design. The findings from this study indicate that a biorefinery can utilize dynamic blending to meet the feedstock quality specifications as well as larger supply radius in the distributed depot-based supply chain design to access more available biomass to handle potential feedstock supply uncertainty.

关键词： Feedstock supply chain mixed-integer linear programming Supply radius Depot Biomass Dynamic blending

来源：评论

学校读者我要写书评

暂无评论

mixed-integer programming Model for Profiling Disease Biomarkers from Gene Expression Studies 5th

Mixed-Integer Programming Model for Profiling Disease Biomar...

引用

5th International Work-Conference on Bioinformatics and Biomedical Engineering (IWBBIO)

作者： Santiago, Andre M. Rocha, Miguel Dourado, Antonio Arrais, Joel P. Univ Minho Dept Informat Braga Portugal Univ Coimbra CISUC Coimbra Portugal

ISBN: (纸本)9783319561547;9783319561530

Biomedical research has seen great advances in recent years, in great part due to the long-term aid of the ability to identify biological or genetic markers that uniquely match a given disease. Despite several successes stories, the reality is that most diseases still lack an effective way of treatment, and even diagnostic. While the emergence of -omic technologies, enabled the screening of a whole cell at the molecular level, the large quantities of data produced restricted the capability to extract valid outcomes. In this paper, we propose an optimization model, based of mixedinteger linear programming, capable of identifying a combination of biomarkers for distinguishing between healthy and diseased samples. The model achieves this taking several individuals' gene expression profiles, identifying the most relevant genes for differentiation and discovering the optimal combination of biomarkers that best explains the difference between both states. This model was validated on two different datasets through sampling analysis, achieving an out of sample accuracy up to 93%.

关键词： Biomarkers Disease diagnostic mixed-integer linear programming

来源：评论

学校读者我要写书评

暂无评论

A comparative analysis of mixed-integer linear formulations for the multi-family capacitated lot-sizing problem

引用

JOURNAL OF INDUSTRIAL AND PRODUCTION ENGINEERING 2018年第4期35卷 229-242页

作者： Arias, Andrea L. Gatica, Ricardo A. Pontificia Univ Catolica Valparaiso Sch Ind Engn Ind Engn Valparaiso Chile Pontificia Univ Catolica Valparaiso Sch Ind Engn Valparaiso Chile Texas Tech Univ Dept Ind Mfg & Syst Engn Lubbock TX 79409 USA

Despite having a very broad spectrum of applicability in practice, the multi-family capacitated lot-sizing problem (MFCLSP) has been scarcely studied. The MFCLSP is an extension of the capacitated lot-sizing problem with setup times (CLST) in which items are organized into families based on similar setup structures. In this paper, we propose three formulations for the MFCLSP (MF-TRAD, MF-ARBNET, and MF-EXREQ), and develop a comprehensive comparative analysis to evaluate their performance using a generic solver (CPLEX). Solving large-scale problems to optimality has been shown to consume a great amount of computational time, which is very impractical for real-life applications. Because of that, this study focuses on analyzing the performance of these formulations in a limited, and reasonable, amount of time. The results show the MF-EXREQ model outperforms the other two models in both the time to the first feasible solution and the quality of the solutions generated throughout the solving process.

关键词： mixed-integer linear programming production planning mathematical modeling multi-family lot-sizing solver performance

来源：评论

学校读者我要写书评

暂无评论

Predictive management of cogeneration-based energy supply networks using two-stage multi-objective optimization

引用

ENERGY 2018年 162卷 1269-1286页

作者： Wakui, Tetsuya Sawada, Kento Yokoyama, Ryohei Aki, Hirohisa Osaka Prefecture Univ Dept Mech Engn 1-1 Caktien Cho Sakai Osaka 5998531 Japan Univ Tsukuba Fac Engn Informat & Syst 1-1-1 Tennodai Tsukuba Ibaraki 3058573 Japan

A predictive management system for cogeneration unit-based energy supply networks using two-stage multi-objective optimization was developed to tackle a trade-off between energy savings and operating cost reduction. The developed system integrated support vector regression-based energy demand prediction, MILP (mixed-integer linear programming)-based schedule planning, and rule-based operation control. The contribution is to develop two-stage MILP-based multi-objective schedule planning, which is extension of an epsilon-constraint method, and operation control rule of multiple cogeneration units. In the first-stage schedule planning, primary energy consumption in the prediction horizon is minimized, and a reduction rate of primary energy consumption is calculated. In the second-stage schedule planning, an operating cost is minimized additionally subject to satisfaction of partial achievement of the reduction rate of primary energy consumption calculated in the first stage. An energy-saving achievement rate is regarded as a decision-making parameter to control a trade-off between energy savings and cost reduction, of which definition is quantitatively apprehensible for decision makers. Annual operating simulation of an energy supply network using four fuel-cell-based cogeneration units revealed that the developed predictive management system has high controllability to the trade-off between the energy saving rates (18.9%-21.6%) and the operating cost reduction rate (19.0%-15.6%), caused by a time-of-use power tariff structure. (C) 2018 Elsevier Ltd. All rights reserved.

关键词： Energy management Multi-objective optimization Microgrid Cogeneration Model predictive control mixed-integer linear programming

来源：评论

学校读者我要写书评

暂无评论

A joint chance-constrained programming approach for the single-item capacitated lot-sizing problem with stochastic demand

引用

ANNALS OF OPERATIONS RESEARCH 2018年第1-2期264卷 123-155页

作者： Gicquel, Celine Cheng, Jianqiang Univ Paris Sud Lab Rech Informat Paris France Univ Arizona Dept Syst & Ind Engn Tucson AZ 85721 USA

We study the single-item single-resource capacitated lot-sizing problem with stochastic demand. We propose to formulate this stochastic optimization problem as a joint chance-constrained program in which the probability that an inventory shortage occurs during the planning horizon is limited to a maximum acceptable risk level. We investigate the development of a new approximate solution method which can be seen as an extension of the previously published sample approximation approach. The proposed method relies on a Monte Carlo sampling of the random variables representing the demand in all planning periods except the first one. Provided there is no dependence between the demand in the first period and the demand in the later periods, this partial sampling results in the formulation of a chance-constrained program featuring a series of joint chance constraints. Each of these constraints involves a single random variable and defines a feasible set for which a conservative convex approximation can be quite easily built. Contrary to the sample approximation approach, the partial sample approximation leads to the formulation of a deterministic mixed-integer linear problem having the same number of binary variables as the original stochastic problem. Our computational results show that the proposed method is more efficient at finding feasible solutions of the original stochastic problem than the sample approximation method and that these solutions are less costly than the ones provided by the Bonferroni conservative approximation. Moreover, the computation time is significantly shorter than the one needed for the sample approximation method.

关键词： Stochastic lot-sizing Chance-constrained programming Joint probabilistic constraint Sample approximation approach mixed-integer linear programming

来源：评论

学校读者我要写书评

暂无评论

Designing Metabolic Division of Labor in Microbial Communities

引用

MSYSTEMS 2019年第2期4卷 e00263-18页

作者： Thommes, Meghan Wang, Taiyao Zhao, Qi Paschalidis, Ioannis C. Segre, Daniel Boston Univ Dept Biomed Engn Boston MA 02215 USA Boston Univ Biol Design Ctr Boston MA 02215 USA Boston Univ Dept Elect & Comp Engn Boston MA 02215 USA Boston Univ Div Syst Engn Boston MA 02215 USA Boston Univ Dept Biol 5 Cummington St Boston MA 02215 USA Boston Univ Dept Phys 590 Commonwealth Ave Boston MA 02215 USA Boston Univ Bioinformat Program Boston MA 02215 USA

Microbes face a trade-off between being metabolically independent and relying on neighboring organisms for the supply of some essential metabolites. This balance of conflicting strategies affects microbial community structure and dynamics, with important implications for microbiome research and synthetic ecology. A "gedanken" (thought) experiment to investigate this trade-off would involve monitoring the rise of mutual dependence as the number of metabolic reactions allowed in an organism is increasingly constrained. The expectation is that below a certain number of reactions, no individual organism would be able to grow in isolation and cross-feeding partnerships and division of labor would emerge. We implemented this idealized experiment using in silico genome-scale models. In particular, we used mixed-integer linear programming to identify trade-off solutions in communities of Escherichia coli strains. The strategies that we found revealed a large space of opportunities in nuanced and nonintuitive metabolic division of labor, including, for example, splitting the tricarboxylic acid (TCA) cycle into two separate halves. The systematic computation of possible solutions in division of labor for 1-, 2-, and 3-strain consortia resulted in a rich and complex landscape. This landscape displayed a non-linear boundary, indicating that the loss of an intracellular reaction was not necessarily compensated for by a single imported metabolite. Different regions in this landscape were associated with specific solutions and patterns of exchanged metabolites. Our approach also predicts the existence of regions in this landscape where independent bacteria are viable but are outcompeted by cross-feeding pairs, providing a possible incentive for the rise of division of labor. IMPORTANCE Understanding how microbes assemble into communities is a fundamental open issue in biology, relevant to human health, metabolic engineering, and environmental sustainability. A possible mechanism f

关键词： division of labor flux balance analysis genome-scale stoichiometric models metabolic networks microbiome mixed-integer linear programming resource allocation synthetic ecology microbial communities

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：