检索结果-内蒙古大学图书馆

Sustainable Process Design and Synthesis of Hydrocarbon Biorefinery through Fast Pyrolysis and Hydroprocessing

AICHE JOURNAL 2014年第3期60卷 980-994页

作者： Zhang, Qiao Gong, Jian Skwarczek, Matthew Yue, Dajun You, Fengqi Northwestern Univ Dept Chem & Biol Engn Evanston IL 60208 USA

The process design and synthesis of hydrocarbon biorefinery, which is composed of fast pyrolysis, biocrude collection, hydroprocessing and hydrogen production sections, under economic and environmental considerations are concerned. A superstructure is developed that includes multiple process alternatives in each stage of the process flow diagram. A bi-criteria mixed integer nonlinear programming model is proposed to maximize the economic performance measured by the net present value and minimize the global warming potential according to life cycle assessment procedures. The bi-criteria mixed integer nonlinear programming model is solved with the ε-constraint method, and the resulting Pareto curve reveals the trade-off between the economic and environmental performance of the process. The two selected “good choice” optimal designs indicate net present values of 573 and 93.6 $MM (unit costs of $3.43 and $5.26 per gallon of gasoline equivalent), corresponding to global warming potentials of 100 and 53 kton CO2 equivalent per year (unit greenhouse emissions of 1.95 and 2.04 kg CO2 per gallon of gasoline equivalent), respectively. ? 2014 American Institute of Chemical Engineers AIChE J, 60: 980–994, 2014

关键词： superstructure fast pyrolysis hydroprocessing hydrogen production mixed integer nonlinear programming life cycle assessment

来源：评论

学校读者我要写书评

暂无评论

Heuristic approaches for support vector machines with the ramp loss

引用

OPTIMIZATION LETTERS 2014年第3期8卷 1125-1135页

作者： Carrizosa, Emilio Nogales-Gomez, Amaya Morales, Dolores Romero Univ Seville Fac Matemat Dept Estadist & Invest Operat Seville Spain Univ Oxford Said Business Sch Oxford England

Recently, Support Vector Machines with the ramp loss (RLM) have attracted attention from the computational point of view. In this technical note, we propose two heuristics, the first one based on solving the continuous relaxation of a mixed integer nonlinear formulation of the RLM and the second one based on the training of an SVM classifier on a reduced dataset identified by an integer linear problem. Our computational results illustrate the ability of our heuristics to handle datasets of much larger size than those previously addressed in the literature.

关键词： Support vector machines Ramp loss mixed integer nonlinear programming Heuristics

来源：评论

学校读者我要写书评

暂无评论

Biobjective sparse principal component analysis

引用

JOURNAL OF MULTIVARIATE ANALYSIS 2014年第0期132卷 151-159页

作者： Carrizosa, Emilio Guerrero, Vanesa Univ Seville Inst Matemat E-41012 Seville Spain

Principal Components are usually hard to interpret. Sparseness is considered as one way to improve interpretability, and thus a trade-off between variance explained by the components and sparseness is frequently sought. In this note we address the problem of simultaneous maximization of variance explained and sparseness, and a heuristic method is proposed. It is shown that recent proposals in the literature may yield dominated solutions, in the sense that other components, found with our procedure, may exist which explain more variance and at the same time are sparser. (C) 2014 Elsevier Inc. All rights reserved.

关键词： Principal component analysis mixed integer nonlinear programming Biobjective optimization Sparseness

来源：评论

学校读者我要写书评

暂无评论

Determination of Network Configuration Considering Inventory Cost in a Supply Chain

引用

JOURNAL OF APPLIED RESEARCH AND TECHNOLOGY 2014年第4期12卷 674-683页

作者： Hernandez Gonzalez, N. M. Alvarez Socarras, A. Mata Perez, M. Univ Autonoma Nuevo Leon San Nicolas De Los Garza Nuevo Leon Mexico

In this paper we show the importance of applying mathematical optimization when designing the distribution network in a supply chain, specifically in making decisions related location of facilities and inventory management, which are associated with different levels of planning but are closely related. The addressed problem is an extension of the classic capacitated facility location problem. The distinguishing features are: the inventory management, the presence of multiple plants, and the single source constraints in both echelons. A key issue is that demand at each distribution center is a function of the demands at the retailers assigned, which is a random variable whose value is not known at the time of designing the network. We focus on the mathematical modeling of the problem and the evaluation of the performance of the developed models, so, it can be observed the troubles that arise when modeling supply chains that consider different types of decisions.

关键词： Supply chain location and inventory problem mixed integer nonlinear programming mixed integer linear programming

来源：评论

学校读者我要写书评

暂无评论

The optimal rounding

引用

MATHEMATICAL programming COMPUTATION 2014年第1期6卷 33-54页

作者： Berthold, Timo Zuse Inst Berlin Dept Optimizat Takustr 7 D-14195 Berlin Germany

This article introduces RENS, the relaxation enforced neighborhood search, a large neighborhood search algorithm for mixed integer nonlinear programs (MINLPs). It uses a sub-MINLP to explore the set of feasible roundings of an optimal solution x of a linear or nonlinear relaxation. The sub-MINLP is constructed by fixing integer variables x(j) with (x) over bar (j) is an element of Z and bounding the remaining integer variables to xj. {[(x) over bar (j)], [(x) over bar (j)]}. We describe two different applications of RENS: as a stand-alone algorithm to compute an optimal rounding of the given starting solution and as a primal heuristic inside a complete MINLP solver. We use the former to compare different kinds of relaxations and the impact of cutting planes on the so-called round-ability of the corresponding optimal solutions. We further utilize RENS to analyze the performance of three rounding heuristics implemented in the branch-cut-and-price framework SCIP. Finally, we study the impact of RENS when it is applied as a primal heuristic inside SCIP. All experiments were performed on three publicly available test sets of mixed integer linear programs (MIPs), mixed integer quadratically constrained programs (MIQCPs), and MINLPs, using solely software which is available in source code. It turns out that for these problem classes 60 to 70% of the instances have roundable relaxation optima and that the success rate of RENS does not depend on the percentage of fractional variables. Last but not least, rens applied as primal heuristic complements nicely with existing primal heuristics in SCIP.

关键词： mixed integer programming mixed integer nonlinear programming Primal heuristic Large neighborhood search Rounding

来源：评论

学校读者我要写书评

暂无评论

Optimization of Reactive Power Compensation for Distribution Power System with Small Hydro Power

Optimization of Reactive Power Compensation for Distribution...

引用

International Conference on Power System Technology (PowerCon)

作者： Han, Yuxin Chen, Laijun Ma, Hongliang Wang, Zhaojian Tsinghua Univ Dept Elect Engn Beijing 100084 Peoples R China Shaanxi Reg Elect Power Grp Co Ltd Xian 710061 Peoples R China

ISBN: (纸本)9781479950324

The voltage in distributed power system (DPS) with runoff small hydro power (RSHP) may break the upper or lower limit due to the uncertainty of power generation of RSHP. Reactive power compensation can mitigate the voltage violation problem. In this paper, the method of determining optimal reactive power compensation configuration in DPS with RSHP is studied. A mixed integer nonlinear programming (MINLP) model is proposed considering the impact of different operation conditions and transformer tap. In addition, a solving algorithm based on the particle swarm optimization (PSO) is adopted to obtain the optimal capacity. Furthermore, two cases derived from the IEEE 33 system are investigated to verify the proposed model and algorithm, and sensitivity of key parameter is analyzed finally.

关键词： small hydro power reactive power compensation mixed integer nonlinear programming particle swarm optimization

来源：评论

学校读者我要写书评

暂无评论

nonlinear Moving Horizon Predictive Control of Ground Vehicles 15

Nonlinear Moving Horizon Predictive Control of Ground Vehicl...

引用

15th IEEE International Symposium on Computational Intelligence and Informatics

作者： Max, Gyorgy Lantos, Bela Budapest Univ Technol & Econ Dept Control Engn & Informat Technol Magyar Tudosok Krt 2 H-1117 Budapest Hungary Szechenyi Istvan Univ Res Ctr Vehicle Ind H-9026 Gyor Hungary

ISBN: (纸本)9781479953370

The paper deals with the approximately time optimal control of automatically driven cars modeled with gear shift as discrete control input beside the continuous ones in a path between two path boundaries. The path boundaries are defined by their corner points that may he the result of image processing in real time or prescribed in advance. The path is divided into sections for which separate optimum control problems are solved in a nonlinear moving horizon predictive control (NMHPC) fashion increasing the semi-online character of the approach. In each section the problem can be formulated as a mixed integer optimal control problem (MIOCP). The resulting MIOCP is solved by reformulating it to static mixed-integer nonlinear program (MINLP) using time discretization and direct multiple shooting method. Non-commercial open software packages are applied that substantially use the gradients of the objective function and the Jacobians of the constraints exploiting sparsity. The elaborated method can be applied both for combustion engine and electric driven cars. It can also form the basis to generate an offline database of a central general collision avoidance system (CAS) for varying path parameters on a grid which can further support real time applications.

关键词： Receding Horizon Predictive Control Direct Multiple Shooting mixed integer nonlinear programming Sparse gradient and Jacobian

来源：评论

学校读者我要写书评

暂无评论

引用

INTERNATIONAL JOURNAL OF LOGISTICS-RESEARCH AND APPLICATIONS 2014年第2期17卷 114-135页

作者： Frias, Luiz Felipe Farias, Isabel A. Wanke, Peter F. Correa, Henrique L. Santos, Luan Petrobras Petr Brasileiro SA Rio De Janeiro Brazil Univ Fed Rio de Janeiro COPPEAD Grad Business Sch Rio De Janeiro Brazil Rollins Coll Crummer Grad Sch Business Winter Pk FL 32789 USA Univ Fed Rio de Janeiro COPPE Grad Sch Engn Rio De Janeiro Brazil

This study investigates the logistics network planning in a major Brazilian petrochemical company, taking into consideration the impact of tax-related costs, in addition to transportation and inventory costs. A mixed integer nonlinear programming model that considers the most relevant costs involved in the network planning process in Brazil was developed and subsequently applied to a case study of a large Brazilian petrochemical company. Our results support anecdotal reports regarding Brazilian companies intensely using ‘product tourism’ to take advantage of different interstate tax rates. Product tourism occurs when a logistically unnecessary flow of goods is established to a lower tax jurisdiction (with a corresponding increase in transportation costs) so that the company obtains a reduction in the amount of the taxes due. View full text

关键词： Brazil logistics network planning mixed integer nonlinear programming petrochemical industry tax-related costs

来源：评论

学校读者我要写书评

暂无评论

Time optimal control of ground vehicles 12

Time optimal control of ground vehicles

引用

12th IEEE International Symposium on Intelligent Systems and Informatics (SISY)

作者： Max, Gyorgy Lantos, Bela Budapest Univ Technol & Econ Dept Control Engn & Informat Technol H-1117 Budapest Hungary Szechenyi Istvan Univ Res Ctr Vehicle Ind H-9026 Gyor Hungary

ISBN: (纸本)9781479959969

The paper deals with the time optimal control of automatically driven cars modeled with gear shift as discrete control input beside the continuous ones in a test path between corridors. The car is required to avoid a static obstacle or performing double lane change. The problem can be formulated as a mixed-integer optimal control problem (MIOCP). The resulting MIOCP is solved by reformulating it to static mixed-integer nonlinear program (MINLP) using time discretization and direct multiple shooting method. Non-commercial open software packages are applied that substantially use the gradients of the objective function and the Jacobians of the constraints exploiting sparsity. A novel algorithm and implementation is presented for computing the derivatives of the complex state trajectory joining equations. This algorithm was given in the form of matrix differential equations whose structure allowed to compute their solution using RK4 in matrix form. The elaborated method can be applied both for combustion engine and electric driven cars. It can form the basis to generate an offline database of a central general collision avoidance system (CAS) for varying path parameters on a grid which can support real time applications.

关键词： Time optimal control Vehicle model Direct multiple shooting mixed integer nonlinear programming Sparse gradient and Jacobian

来源：评论

学校读者我要写书评

暂无评论

Scheduling elective surgeries with sequence-dependent setup times to multiple operating rooms using constraint programming

引用

OPERATIONS RESEARCH FOR HEALTH CARE 2014年第3期3卷 160-167页

作者： Zhao, Zhaoxia Li, Xueping Univ Tennessee Dept Ind & Syst Engn 522 John D Tickle Bldg851 Neyland Dr Knoxville TN 37996 USA

The problem studied in this paper is to schedule elective surgeries (in contrast to urgent surgeries) to multiple operating rooms (ORs) in ambulatory surgical settings. We focus on three aspects of the daily scheduling decisions, including the number of ORs to open, the allocation of surgery-to-OR, and the sequence of surgeries in each OR. All the surgeries to be scheduled are known in advance, which is a common assumption for elective surgery scheduling problems. The surgeries belong to different types, and each OR can only allow certain types of surgeries to be performed. Before a surgery starts, some setup work needs to be done, such as sterilization and preparing required equipment. The setup times are assumed sequence-dependent, and both setup times and surgery durations are deterministic. The fixed costs of running the ORs are high;while sometimes overtime costs, which are even higher than the fixed costs, may occur when the surgeries cannot be done within the normal operating period of the ORs. We build a mixed integer nonlinear programming (MINLP) model and a Constraint programming (CP) model to solve this problem. The performance of these two models is tested on numerical examples, and the results show that the CP model is more efficient than the MINLP model in terms of the computational time and solution quality. We also examine the sensitivity of the solutions to the variation of surgery durations, and the analysis shows that the total costs do not change much when the variations of surgery durations are small. (C) 2014 Elsevier Ltd. All rights reserved.

关键词： Elective surgery scheduling Multiple operating rooms Sequence-dependent setup time Constraint programming mixed integer nonlinear programming

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：