A primal-dual interior point method for large-scale free material optimization
Weldeyesus, Alemseged Gebrehiwot; Stolpe, Mathias
2015-01-01
optimization problem is a nonlinear semidefinite program with many small matrix inequalities for which a special-purpose optimization method should be developed. The objective of this article is to propose an efficient primal-dual interior point method for FMO that can robustly and accurately solve large...
Generic primal-dual interior point methods based on a new kernel function
EL Ghami, M.; Roos, C.
2008-01-01
In this paper we present a generic primal-dual interior point methods (IPMs) for linear optimization in which the search direction depends on a univariate kernel function which is also used as proximity measure in the analysis of the algorithm. The proposed kernel function does not satisfy all the c
Wen-bao Ai
2004-01-01
In this paper we present a dynamic optimal method for adjusting the centering pa-rameter in the wide-neighborhood primal-dual interior-point algorithms for linear pro-gramming, while the centering parameter is generally a constant in the classical wide-neighborhood primal-dual interior-point algorithms. The computational results show thatthe new method is more efficient.
Antonio Roberto Balbo
2012-01-01
Full Text Available This paper proposes a predictor-corrector primal-dual interior point method which introduces line search procedures (IPLS in both the predictor and corrector steps. The Fibonacci search technique is used in the predictor step, while an Armijo line search is used in the corrector step. The method is developed for application to the economic dispatch (ED problem studied in the field of power systems analysis. The theory of the method is examined for quadratic programming problems and involves the analysis of iterative schemes, computational implementation, and issues concerning the adaptation of the proposed algorithm to solve ED problems. Numerical results are presented, which demonstrate improvements and the efficiency of the IPLS method when compared to several other methods described in the literature. Finally, postoptimization analyses are performed for the solution of ED problems.
Komputasi Aliran Daya Optimal Sistem Tenaga Skala Besar dengan Metode Primal Dual Interior Point
Syafii Syafii
2016-03-01
Full Text Available This paper focuses on the use of Primal Dual Interior Point method in the analysis of optimal power flow. Optimal power flow analysis with Primal Dual Interior Point method then compared with Linear Programming Method using Matpower program. The simulation results show that the computation results of Primal Dual Interior Point similar with Linear Programming Method for total cost of generation and large power generated by each power plant. But in terms of computation time Primal Dual Interior Point method is faster than the method of Linear Programming, especially for large systems. Primal Dual Interior Point method have solved the problem in 40.59 seconds, while Linear Programming method takes longer 239.72 seconds for large-scale system 9241 bus. This is because the settlement PDIP algorithm starts from the starting point x0, which is located within the area of feasible move towards the optimal point, in contrast to the simplex method that moves along the border of the feasible from one extreme point to the other extreme point. Thus Primal Dual Interior Point method have more efficient in solving optimal power flow problem of large-scale power systems.
求解非线性规划的原始对偶内点法%A Primal-dual Interior Point Method for Nonlinear Programming
张珊; 姜志侠
2008-01-01
In this paper, we propose a primal-dual interior point method for solving general constrained nonlinear programming problems. To avoid the situation that the algorithm we use may converge to a saddle point or a local maximum, we utilize a merit function to guide the iterates toward a local minimum. Especially, we add the parameter ε to the Newton system when calculating the decrease directions. The global convergence is achieved by the decrease of a merit function. Furthermore, the numerical results confirm that the algorithm can solve this kind of problems in an efficient way.
A Primal-Dual Interior Point-Linear Programming Algorithm for MPC
Edlund, Kristian; Sokoler, Leo Emil; Jørgensen, John Bagterp
2009-01-01
Constrained optimal control problems for linear systems with linear constraints and an objective function consisting of linear and l1-norm terms can be expressed as linear programs. We develop an efficient primal-dual interior point algorithm for solution of such linear programs. The algorithm...
HUANG Hui; FEI Pu-sheng; YUAN Yuan
2005-01-01
A primal-dual infeasible-interior-point algorithm for multiple objective linear programming (MOLP) problems was presented. In contrast to the current MOLP algorithm,moving through the interior of polytope but not confining the iterates within the feasible region in our proposed algorithm result in a solution approach that is quite different and less sensitive to problem size, so providing the potential to dramatically improve the practical computation effectiveness.
Yan Qin BAI; Guo Qiang WANG
2007-01-01
A class of polynomial primal-dual interior-point algorithms for second-order cone optimization based on a new parametric kernel function, with parameters p and q, is presented. Its growth term is between linear and quadratic. Some new tools for the analysis of the algorithms are proposed.The complexity bounds of O(√Nlog N log N/ε) for large-update methods and O(√Nlog N/ε) for smallupdate methods match the best known complexity bounds obtained for these methods. Numerical tests demonstrate the behavior of the algorithms for different results of the parameters p and q.
INTAN S. AHMAD
2008-04-01
Full Text Available This work presents the application of a primal-dual interior point method to minimax optimisation problems. The algorithm differs significantly from previous approaches as it involves a novel non-monotone line search procedure, which is based on the use of standard penalty methods as the merit function used for line search. The crucial novel concept is the discretisation of the penalty parameter used over a finite range of orders of magnitude and the provision of a memory list for each such order. An implementation within a logarithmic barrier algorithm for bounds handling is presented with capabilities for large scale application. Case studies presented demonstrate the capabilities of the proposed methodology, which relies on the reformulation of minimax models into standard nonlinear optimisation models. Some previously reported case studies from the open literature have been solved, and with significantly better optimal solutions identified. We believe that the nature of the non-monotone line search scheme allows the search procedure to escape from local minima, hence the encouraging results obtained.
季聪; 卫志农; 汤涌; 孙国强; 韦延方; 孙永辉
2012-01-01
Based on steady state power flow model of voltage source converter-high voltage direct current (VSC-HVDC) power transmission system and combining with automatic differentiation (AD) technology, a primal-dual interior point method-based algorithm for optimal power flow (OPF) of AC/DC power grid was proposed. Using high efficient AD tool based on operator overloading the Jacobian and Hessian matrices were generated, thus the work load for derivation of differential expressions and code compiling could be reduced and the development efficiency of program could be improved. Simulation results of calculation examples showed that in the solution of OPF problem of AC/DC power grid containing VSC-HVDC power transmission system the high efficiency of traditional primal-dual interior point method could be kept and it possessed satisfied adaptability to the combination of different VSC control modes.%根据电压源换流器-高压直流输电(voltage source converter-high voltage direct current,VSC-HVDC)的稳态潮流模型,结合自动微分(automatic differentiation,AD)技术,提出一种基于原对偶内点法的交直流系统最优潮流算法.该算法利用高效的基于操作符重载的AD工具生成雅可比(Jacobian)矩阵和海森(Hessian)矩阵,减少了微分表达式推导和代码编写的工作量,提高了程序的开发效率.多个算例的仿真结果表明,该算法保持了传统原对偶内点法在解决含VSC-HVDC的交直流最优潮流问题上的高效性,且对VSC的不同控制方式组合均具有良好的适应性.
Borsic, A.; Adler, A.
2012-09-01
Maximum a posteriori estimates in inverse problems are often based on quadratic formulations, corresponding to a least-squares fitting of the data and to the use of the L2 norm on the regularization term. While the implementation of this estimation is straightforward and usually based on the Gauss-Newton method, resulting estimates are sensitive to outliers and result in spatial distributions of the estimates that are smooth. As an alternative, the use of the L1 norm on the data term renders the estimation robust to outliers, and the use of the L1 norm on the regularization term allows the reconstruction of sharp spatial profiles. The ability therefore to use the L1 norm either on the data term, on the regularization term, or on both is desirable, though the use of this norm results in non-smooth objective functions which require more sophisticated implementations compared to quadratic algorithms. Methods for L1-norm minimization have been studied in a number of contexts, including in the recently popular total variation regularization. Different approaches have been used and methods based on primal-dual interior-point methods (PD-IPMs) have been shown to be particularly efficient. In this paper we derive a PD-IPM framework for using the L1 norm indifferently on the two terms of an inverse problem. We use electrical impedance tomography as an example inverse problem to demonstrate the implementation of the algorithms we derive, and the effect of choosing the L2 or the L1 norm on the two terms of the inverse problem. Pseudo-codes for the algorithms and a public domain implementation are provided.
Potra, Florian A.; Wright, Stephen J.
2000-12-01
The modern era of interior-point methods dates to 1984, when Karmarkar proposed his algorithm for linear programming. In the years since then, algorithms and software for linear programming have become quite sophisticated, while extensions to more general classes of problems, such as convex quadratic programming, semi-definite programming, and nonconvex and nonlinear problems, have reached varying levels of maturity. We review some of the key developments in the area, including comments on both the complexity theory and practical algorithms for linear programming, semi-definite programming, monotone linear complementarity, and convex programming over sets that can be characterized by self-concordant barrier functions.
王国强; 白延琴
2006-01-01
In the present paper we present a class of polynomial primal-dual interior-point algorithms for semidefinite optimization based on a kernel function. This kernel function is not a so-called self-regular function due to its growth term increasing linearly. Some new analysis tools were developed which can be used to deal with complexity analysis of the algorithms which use analogous strategy in [ 5 ]to design the search directions for the Newton system. The complexity bounds for the algorithms with large- and small-update methods were obtained, namely, O( qn(p+q)/q(p+1)) log n/ε and O( q2√n) log n/ε, respectively.
刘中意
2009-01-01
最近Peng等人使用新的搜索方向和自正则度量为求解线性规划问题提出了一个原始对偶内点法.本文将这个长步法延伸到凸二次规划.在线性规划情形时,原始空间和对偶空间中的尺度Newton方向是正交的,而在二次规划情形时这是不成立的.本文将处理这个问题并且证明多项式复杂性,并且得到复杂性的上界为O(n√log n log (n/ε)).%Recently Peng et al. have proposed a primal-dual interiorpoint method with new search directions and self-regular proximity for LP.We extend this large-update method to convex quadratic programming (QP).In the case of LP,the scaled Newton directions in the primal and dual spaces are orthogonal.Note that this is not true in the case of QP.In this paper we deal with the problem and polynomial complexity is proved,and the iteration bound is O(√nlog n log (n/ε)).
程莹; 刘明波
2001-01-01
针对无功优化计算中离散变量和连续变量共存问题，提出用直接非线性原—对偶内点法内嵌罚函数的新算法。通过对几个不同规模试验系统计算分析，并与Tabu搜索法求得的结果比较，证明了该方法是有效的，而且在计算速度、收敛性和优化精度上都优于Tabu搜索法。这使内点法在解决非线性混合整数规划无功优化的有效性和实用性方面更进了一步。%A new algorithm for reactive power optimization problem involving both discrete and continuous variables is presented, which incorporating a penalty function into the nonlinear primal-dual interior point algorithm. By comparing with Tabu search method, the numerical results of several test systems show that the proposed method is effective, and is superior to Tabu search method on side of computation speed, convergence and optimization accuracy. The effectiveness and practicality of the interior point algorithm in solving nonlinear mixed integer programming model of reactive power optimization is improved.
A Primal-Dual Augmented Lagrangian Method for Optimal Control of ...
A Primal-Dual Augmented Lagrangian Method for Optimal Control of ... Log in or Register to get access to full text downloads. ... In this paper we are concerned with time-varying optimal control problems whose cost is quadratic and whose ...
A new warmstarting strategy for the primal-dual column generation method
Gondzio, Jacek; Gonzalez-Brevis, Pablo
2015-01-01
This paper presents a new warmstarting technique in the context of a primal-dual column generation method applied to solve a particular class of combinatorial optimization problems. The technique relies on calculating an initial point and on solving auxiliary linear optimization problems to determine the step direction needed to fully restore primal and dual feasibilities after new columns arrive. Conditions on the maximum size of the cuts and on a suitable initial point are discussed. Additi...
张明望; 黄崇超
2001-01-01
In this paper, we devise a primal-dual infeasible interior point algorithm for convex quadratic programming problem with box constraints.Under assumption that initial point is in neighborhood of the path of conters,we prove that algorithm enjoys the global convergence.%对框式凸二次规划提出了一种原始—对偶不可行内点算法，在初始点取在中心路径的邻域N时，证明了算法的全局收敛性。
Tian, Wenyi; Yuan, Xiaoming
2016-11-01
Linear inverse problems with total variation regularization can be reformulated as saddle-point problems; the primal and dual variables of such a saddle-point reformulation can be discretized in piecewise affine and constant finite element spaces, respectively. Thus, the well-developed primal-dual approach (a.k.a. the inexact Uzawa method) is conceptually applicable to such a regularized and discretized model. When the primal-dual approach is applied, the resulting subproblems may be highly nontrivial and it is necessary to discuss how to tackle them and thus make the primal-dual approach implementable. In this paper, we suggest linearizing the data-fidelity quadratic term of the hard subproblems so as to obtain easier ones. A linearized primal-dual method is thus proposed. Inspired by the fact that the linearized primal-dual method can be explained as an application of the proximal point algorithm, a relaxed version of the linearized primal-dual method, which can often accelerate the convergence numerically with the same order of computation, is also proposed. The global convergence and worst-case convergence rate measured by the iteration complexity are established for the new algorithms. Their efficiency is verified by some numerical results.
Convex relaxation for a 3D spatiotemporal segmentation model using the primal-dual method
Shi-yan WANG; Hui-min YU
2012-01-01
A method based on 3D videos is proposed for multi-target segmentation and tracking with a moving viewing system.A spatiotemporal energy functional is built up to perform motion segmentation and estimation simultaneously.To overcome the limitation of the local minimum problem with the level set method,a convex relaxation method is applied to the 3D spatiotemporal segmentation model.The relaxed convex model is independent of the initial condition.A primal-dual algorithm is used to improve computational efficiency.Several indoor experiments show the validity of the proposed method.
An Efficient Primal-Dual Prox Method for Non-Smooth Optimization
Yang, Tianbao; Mehdavi, Mehrdad; Zhu, Shenghuo
2012-01-01
We consider the non-smooth optimization problems in machine learning, where both the loss function and the regularizer are non-smooth functions. Previous studies on efficient empirical loss minimization assume either a smooth loss function or a strongly convex regularizer, making them unsuitable for non-smooth optimization. We develop an efficient method for a family of non-smooth optimization where the dual form of the loss function is bilinear in primal and dual variables. We cast a non-smooth optimization problem into a minimax optimization problem, and develop a primal dual prox method that solves the minimax optimization problem at a rate of $O(1/T)$, significantly faster than a standard gradient descent method ($O(1/\\sqrt{T})$). Our empirical study verifies the efficiency of the proposed method for non-smooth optimization by comparing it to the state-of-the-art first order methods.
Ad Hoc Microphone Array Beamforming Using the Primal-Dual Method of Multipliers
Tavakoli, Vincent Mohammad; Jensen, Jesper Rindom; Heusdens, Richard;
2016-01-01
In the recent years, there have been increasing amount of researches aiming at optimal beamforming with ad hoc microphone arrays, mostly with fusion-based schemes. However, huge amount of computational complexity and communication overhead impede many of these algorithms from being useful...... in practice. In this paper, we propose a low-footprint optimization approach to reduce the convergence time and overheads for the convex beamforming problem. We transcribe the beamforming with pseudo-coherence-based formulation which is insightful for taking into account the nature of speech. We formulate...... the distributed linearly-constrained minimum variance beamformer using the the state of the art primal-dual method of multipliers. We study the proposed algorithm with an experiment....
A Polynomial Primal-Dual Interior Point Method for Convex Programming with Quadratic Constraints
1993-04-01
Delft Un~versity of Technology, Delft, Netherlands. [3H Bazaraa , M. S., J. J. Jarvis, and H. D. Sh’rali. 199a Linar Pgrammning a" N]tdiwk Flow, John... Bazaraa , M. S., J. J. Jarvis, and H. D. Sherali. 1990. IjnW Programming and Network Flw, John Wiley and Sons, New York. [4] Charnes, A., and K. 0. Kortanek...often used in linear programming. For a detailed discussion of that 90 application, see Bazaraa . Jarvis. and Sherali(1990). Given J£, let T denote the
An Efficient Primal-Dual Interior-Point Method for Minimizing a Sum of Euclidean Norms
1998-08-17
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钱忠根; 白延琴
2005-01-01
In this paper, primal-dual interior-point algorithm with dynamic step size is implemented for linear programming (LP) problems. The algorithms are based on a few kernel functions, including both self-regular functions and non-self-regular ones. The dynamic step size is compared with fixed step size for the algorithms in inner iteration of Newton step. Numerical tests show that the algorithms with dynamic step size are more efficient than those with fixed step size.
Skajaa, Anders; Andersen, Erling D.; Ye, Yinyu
2013-01-01
We present two strategies for warmstarting primal-dual interior point methods for the homogeneous self-dual model when applied to mixed linear and quadratic conic optimization problems. Common to both strategies is their use of only the final (optimal) iterate of the initial problem...... and their negligible computational cost. This is a major advantage when compared to previously suggested strategies that require a pool of iterates from the solution process of the initial problem. Consequently our strategies are better suited for users who use optimization algorithms as black-box routines which...... worst-case complexity. We present extensive computational results showing work reductions when warmstarting compared to coldstarting in the range 30–75% depending on the problem class and magnitude of the problem perturbation. The computational experiments thus substantiate that the warmstarting...
黄静静; 商朋见; 王爱文
2011-01-01
将半定规划(Semidefinite Programming,SDP)的内点算法推广到二次半定规划(QuadraticSemidefinite Programming,QSDP),重点讨论了AHO搜索方向的产生方法.首先利用Wolfe对偶理论推导得到了求解二次半定规划的非线性方程组,利用牛顿法求解该方程组,得到了求解QSDP的内点算法的AHO搜索方向,证明了该搜索方向的存在唯一性,最后给出了求解二次半定规划的预估校正内点算法的具体步骤,并对基于不同搜索方向的内点算法进行了数值实验,结果表明基于NT方向的内点算法最为稳健.%This paper extends the interior point algorithm for solving Semidefinite Programming (SDP) to Quadratic Semidefinite Programming(QSDP) and especially discusses the generation of AHO search direction. Firstly, we derive the nonlinear equations for solving QSDP using Wolfe's dual theorem.The AHO search direction is got by applying Newton' s method to the equations. Then we prove the existence and uniqueness of the search direction, and give the detaied steps of predictor-corrector interior-point algorithm. At last, this paper provides a numerical comparison of the algoritms using three different search directions and suggests the algorithm using NT direction is the most robust.
An interior-point method for the Cartesian P*(k-linear complementarity problem over symmetric cones
B Kheirfam
2014-06-01
Full Text Available A novel primal-dual path-following interior-point algorithm for the Cartesian P*(k-linear complementarity problem over symmetric cones is presented. The algorithm is based on a reformulation of the central path for finding the search directions. For a full Nesterov-Todd step feasible interior-point algorithm based on the new search directions, the complexity bound of the algorithm with small-update approach is the best-available bound.
On Implementing a Homogeneous Interior-Point Algorithm for Nonsymmetric Conic Optimization
Skajaa, Anders; Jørgensen, John Bagterp; Hansen, Per Christian
Based on earlier work by Nesterov, an implementation of a homogeneous infeasible-start interior-point algorithm for solving nonsymmetric conic optimization problems is presented. Starting each iteration from (the vicinity of) the central path, the method computes (nearly) primal-dual symmetric......-cone problem, the facility location problem, entropy problems and geometric programs; all formulated as nonsymmetric conic optimization problems....
J.F. Sturm; J. Zhang (Shuzhong)
1996-01-01
textabstractIn this paper we introduce a primal-dual affine scaling method. The method uses a search-direction obtained by minimizing the duality gap over a linearly transformed conic section. This direction neither coincides with known primal-dual affine scaling directions (Jansen et al., 1993; Mon
Distributed Interior-point Method for Loosely Coupled Problems
Pakazad, Sina Khoshfetrat; Hansson, Anders; Andersen, Martin Skovgaard
2014-01-01
’s method and utilizes proximal splitting to distribute the computations for calculating the Newton step at each iteration. A combination of this algorithm and the interior-point method is then used to introduce a distributed algorithm for solving constrained loosely coupled problems. We also provide...
A predictor-corrector interior-point algorithm for monotone variational inequality problems
梁昔明; 钱积新
2002-01-01
Mehrotra's recent suggestion of a predictor-corrector variant of primal-dual interior-point method for linear programming is currently the interior-point method of choice for linear programming. In this work the authors give a predictor-corrector interior-point algorithm for monotone variational inequality problems. The algorithm was proved to be equivalent to a level-1 perturbed composite Newton method. Computations in the algorithm do not require the initial iteration to be feasible. Numerical results of experiments are presented.
Multiperiod hydrothermal economic dispatch by an interior point method
Kimball L. M.
2002-01-01
Full Text Available This paper presents an interior point algorithm to solve the multiperiod hydrothermal economic dispatch (HTED. The multiperiod HTED is a large scale nonlinear programming problem. Various optimization methods have been applied to the multiperiod HTED, but most neglect important network characteristics or require decomposition into thermal and hydro subproblems. The algorithm described here exploits the special bordered block diagonal structure and sparsity of the Newton system for the first order necessary conditions to result in a fast efficient algorithm that can account for all network aspects. Applying this new algorithm challenges a conventional method for the use of available hydro resources known as the peak shaving heuristic.
Dynamic economic dispatch combining network flow and interior point method
韩学山; 赵建国; 柳焯
2003-01-01
Under the environment of electric power market, economic dispatch (ED) problem should consider network constraints, unit ramp rates, besides the basic constraints. For this problem, it is important to establish the effective model and algorithm. This paper examines the decoupled conditions that affect the solution optimality to this problem. It proposes an effective model and solution method. Based on the look-ahead technique, it finds the number of time intervals to guarantee the solution optimality. Next, an efficient technique for finding the optimal solution via the interior point methods is described. Test cases, which include dispatching six units over 5 time intervals on the IEEE 30 test system with line flows and ramp constraints are presented. Results indicate that the computational effort as measured by iteration counts or execution time varies only modestly with the problem size.
Optimal Power Flow by Interior Point and Non Interior Point Modern Optimization Algorithms
Marcin Połomski
2013-03-01
Full Text Available The idea of optimal power flow (OPF is to determine the optimal settings for control variables while respecting various constraints, and in general it is related to power system operational and planning optimization problems. A vast number of optimization methods have been applied to solve the OPF problem, but their performance is highly dependent on the size of a power system being optimized. The development of the OPF recently has tracked significant progress both in numerical optimization techniques and computer techniques application. In recent years, application of interior point methods to solve OPF problem has been paid great attention. This is due to the fact that IP methods are among the fastest algorithms, well suited to solve large-scale nonlinear optimization problems. This paper presents the primal-dual interior point method based optimal power flow algorithm and new variant of the non interior point method algorithm with application to optimal power flow problem. Described algorithms were implemented in custom software. The experiments show the usefulness of computational software and implemented algorithms for solving the optimal power flow problem, including the system model sizes comparable to the size of the National Power System.
Local Grid Reactive Power Optimization Based on Improved Interior Point Method%基于改进内点法的区域电网无功优化
刘曦; 庞霞; 刘崇新
2014-01-01
Introduction was made to the branch primal-dual path tracking method of interior point method. Aiming at reactive volt-age present state of a local grid, this paper established the objective function with the minimum network loss for reactive power op-timization in concurrent of best voltage quality carrying out reactive power optimization to effectively reduce active network loss of the system. The optimization method for reactive power optimization of large-scaled grid has certain guiding significance.%介绍了内点法的分支原对偶路径跟踪法，并针对某区域电网的无功电压现状，建立以网损最小为目标函数，并兼顾电压质量最好进行无功优化，有效降低了系统的有功网损，同时电压质量也得到提高。该优化方法对于大规模电网的无功优化具有一定的指导意义。
Interior Point Methods on GPU with application to Model Predictive Control
Gade-Nielsen, Nicolai Fog
The goal of this thesis is to investigate the application of interior point methods to solve dynamical optimization problems, using a graphical processing unit (GPU) with a focus on problems arising in Model Predictice Control (MPC). Multi-core processors have been available for over ten years now...... equations of the Hessian matrix. The use of a GPU has been shown to be very efficient in the factorization of dense matrices, and several numeric libraries, which utilize the GPU, have become available during the course of this thesis. We have developed a direct interior point method, which utilizes the GPU...... of different optimization algorithms are available for solving optimization problems. Some of the most common method are the simplex method and interior point methods. We focus on interior point methods in this thesis, due to its polynomial complexity, and since the use of the simplex method with GPUs have...
An Interior Point Path-following Method for Nonconvex Programming With Quasi Normal Cone Condition
无
2000-01-01
@@Since Karmarkar's famous paper［1］ on a new polynomial interior point algorithm for linear programming was published in 1984, interior point methods have been proven to be a class of efficient methods for mathematical programming and have been paid muchattention. Up till now, theories, algorithms and applications of interior point methods for linear programming as well as convex nonlinear programming have been well studied (see ［2］ and references therein), however, few results on nonconvex programming have been published. For nonconvex problem, the existence of interior path to a solution, which is trivial for linear and convex programming, becomes a key problem. In ［3,4］, the so-called normal cone condition (NCC) was introduced and used for a class of nonconvex programming problem, that is, the out normal cone of a feasible set cannot meet the strictly feasible set. This condition is a generalization of the convexity, in other words, it imposes restrictions on nonconvexity of the feasible set. A combined homotopy interior point method was constructed, and the existence of the interior path from a known interior point to a solution of the K-K-T system for nonconvex programming with the NCC was proven.
Full-Newton step interior-point methods for conic optimization
Mansouri, H.
2008-01-01
In the theory of polynomial-time interior-point methods (IPMs) two important classes of methods are distinguished: small-update and large-update methods, respectively. Small-update IPMs have the best theoretical iteration bound and IPMs with full-Newton steps belong to this class of methods. Within
Full-Newton step interior-point methods for conic optimization
Mansouri, H.
2008-01-01
In the theory of polynomial-time interior-point methods (IPMs) two important classes of methods are distinguished: small-update and large-update methods, respectively. Small-update IPMs have the best theoretical iteration bound and IPMs with full-Newton steps belong to this class of methods. Within
Design of a Distribution Network Using Primal-Dual Decomposition
J. A. Marmolejo
2016-01-01
Full Text Available A method to solve the design of a distribution network for bottled drinks company is introduced. The distribution network proposed includes three stages: manufacturing centers, consolidation centers using cross-docking, and distribution centers. The problem is formulated using a mixed-integer programming model in the deterministic and single period contexts. Because the problem considers several elements in each stage, a direct solution is very complicated. For medium-to-large instances the problem falls into large scale. Based on that, a primal-dual decomposition known as cross decomposition is proposed in this paper. This approach allows exploring simultaneously the primal and dual subproblems of the original problem. A comparison of the direct solution with a mixed-integer lineal programming solver versus the cross decomposition is shown for several randomly generated instances. Results show the good performance of the method proposed.
A PREDICTOR-CORRECTOR INTERIOR-POINT ALGORITHM FOR CONVEX QUADRATIC PROGRAMMING
梁昔明; 钱积新
2002-01-01
The simplified Newton method, at the expense of fast convergence, reduces the work required by Newton method by reusing the initial Jacobian matrix. The composite Newton method attempts to balance the trade-off between expense and fast convergence by composing one Newton step with one simplified Newton step. Recently, Mehrotra suggested a predictor-corrector variant of primal-dual interior point method for linear programming. It is currently the interiorpoint method of the choice for linear programming. In this work we propose a predictor-corrector interior-point algorithm for convex quadratic programming. It is proved that the algorithm is equivalent to a level-1 perturbed composite Newton method. Computations in the algorithm do not require that the initial primal and dual points be feasible. Numerical experiments are made.
Yi-hua Zhong
2013-01-01
Full Text Available Recently, various methods have been developed for solving linear programming problems with fuzzy number, such as simplex method and dual simplex method. But their computational complexities are exponential, which is not satisfactory for solving large-scale fuzzy linear programming problems, especially in the engineering field. A new method which can solve large-scale fuzzy number linear programming problems is presented in this paper, which is named a revised interior point method. Its idea is similar to that of interior point method used for solving linear programming problems in crisp environment before, but its feasible direction and step size are chosen by using trapezoidal fuzzy numbers, linear ranking function, fuzzy vector, and their operations, and its end condition is involved in linear ranking function. Their correctness and rationality are proved. Moreover, choice of the initial interior point and some factors influencing the results of this method are also discussed and analyzed. The result of algorithm analysis and example study that shows proper safety factor parameter, accuracy parameter, and initial interior point of this method may reduce iterations and they can be selected easily according to the actual needs. Finally, the method proposed in this paper is an alternative method for solving fuzzy number linear programming problems.
Lesaja, G.; Roos, C.
2011-01-01
We present an interior-point method for monotone linear complementarity problems over symmetric cones (SCLCP) that is based on barrier functions which are defined by a large class of univariate functions, called eligible kernel functions. This class is fairly general and includes the classical logar
Infeasible Interior-Point Methods for Linear Optimization Based on Large Neighborhood
Asadi, A.R.; Roos, C.
2015-01-01
In this paper, we design a class of infeasible interior-point methods for linear optimization based on large neighborhood. The algorithm is inspired by a full-Newton step infeasible algorithm with a linear convergence rate in problem dimension that was recently proposed by the second author. Unfortu
Infeasible Interior-Point Methods for Linear Optimization Based on Large Neighborhood
Asadi, A.R.; Roos, C.
2015-01-01
In this paper, we design a class of infeasible interior-point methods for linear optimization based on large neighborhood. The algorithm is inspired by a full-Newton step infeasible algorithm with a linear convergence rate in problem dimension that was recently proposed by the second author.
Infeasible Interior-Point Methods for Linear Optimization Based on Large Neighborhood
Asadi, A.R.; Roos, C.
2015-01-01
In this paper, we design a class of infeasible interior-point methods for linear optimization based on large neighborhood. The algorithm is inspired by a full-Newton step infeasible algorithm with a linear convergence rate in problem dimension that was recently proposed by the second author. Unfortu
Barboza, Luciano Vitoria [Sul-riograndense Federal Institute for Education, Science and Technology (IFSul), Pelotas, RS (Brazil)], E-mail: luciano@pelotas.ifsul.edu.br
2009-07-01
This paper presents an overview about the maximum load ability problem and aims to study the main factors that limit this load ability. Specifically this study focuses its attention on determining which electric system buses influence directly on the power demand supply. The proposed approach uses the conventional maximum load ability method modelled by an optimization problem. The solution of this model is performed using the Interior Point methodology. As consequence of this solution method, the Lagrange multipliers are used as parameters that identify the probable 'bottlenecks' in the electric power system. The study also shows the relationship between the Lagrange multipliers and the cost function in the Interior Point optimization interpreted like sensitivity parameters. In order to illustrate the proposed methodology, the approach was applied to an IEEE test system and to assess its performance, a real equivalent electric system from the South- Southeast region of Brazil was simulated. (author)
The complexity of interior point methods for solving discounted turn-based stochastic games
Hansen, Thomas Dueholm; Ibsen-Jensen, Rasmus
2013-01-01
We study the problem of solving discounted, two player, turn based, stochastic games (2TBSGs). Jurdziński and Savani showed that in the case of deterministic games the problem can be reduced to solving P-matrix linear complementarity problems (LCPs). We show that the same reduction also works...... for general 2TBSGs. This implies that a number of interior point methods can be used to solve 2TBSGs. We consider two such algorithms: the unified interior point method of Kojima, Megiddo, Noma, and Yoshise, and the interior point potential reduction algorithm of Kojima, Megiddo, and Ye. The algorithms run...... states and discount factor γ we get κ=Θ(n(1−γ)2) , −δ=Θ(n√1−γ) , and 1/θ=Θ(n(1−γ)2) in the worst case. The lower bounds for κ, − δ, and 1/θ are all obtained using the same family of deterministic games....
A primal-dual decomposition based interior point approach to two-stage stochastic linear programming
A.B. Berkelaar (Arjan); C.L. Dert (Cees); K.P.B. Oldenkamp; S. Zhang (Shuzhong)
1999-01-01
textabstractDecision making under uncertainty is a challenge faced by many decision makers. Stochastic programming is a major tool developed to deal with optimization with uncertainties that has found applications in, e.g. finance, such as asset-liability and bond-portfolio management. Computationa
Improved Full-Newton-Step Infeasible Interior-Point Method for Linear Complementarity Problems
Goran Lešaja
2016-04-01
Full Text Available We present an Infeasible Interior-Point Method for monotone Linear Complementarity Problem (LCP which is an improved version of the algorithm given in [13]. In the earlier version, each iteration consisted of one feasibility step and few centering steps. The improved version guarantees that after one feasibility step, the new iterate is feasible and close enough to the central path thanks to the much tighter proximity estimate which is based on the new lemma introduced in [18]. Thus, the centering steps are eliminated. Another advantage of this method is the use of full-Newton-steps, that is, no calculation of the step size is required. The preliminary implementation and numerical results demonstrate the advantage of the improved version of the method in comparison with the old one.
钱忠根; 白延琴; 王国强
2008-01-01
Interior-point methods (IPMs) for linear optimization (LO) and semidefinite optimization (SDO) have become a hot area in mathematical programming in the last decades. In this paper, a new kernel function with simple algebraic expression is proposed. Based on this kernel function, a primal-dual interior-point methods (IPMs) for semidefinite optimization (SDO) is designed. And the iteration complexity of the algorithm as O(n3/4 log n/ε) with large-updates is established. The resulting bound is better than the classical kernel function, with its iteration complexity O(n log n/ε) in large-updates case.
A Primal-Dual Approach for a Total Variation Wasserstein Flow
Benning, Martin
2013-01-01
We consider a nonlinear fourth-order diffusion equation that arises in denoising of image densities. We propose an implicit time-stepping scheme that employs a primal-dual method for computing the subgradient of the total variation seminorm. The constraint on the dual variable is relaxed by adding a penalty term, depending on a parameter that determines the weight of the penalisation. The paper is furnished with some numerical examples showing the denoising properties of the model considered. © 2013 Springer-Verlag.
Zamora, A.; Gutierrez, A. E.; Velasco, A. A.
2014-12-01
2- and 3-Dimensional models obtained from the inversion of geophysical data are widely used to represent the structural composition of the Earth and to constrain independent models obtained from other geological data (e.g. core samples, seismic surveys, etc.). However, inverse modeling of gravity data presents a very unstable and ill-posed mathematical problem, given that solutions are non-unique and small changes in parameters (position and density contrast of an anomalous body) can highly impact the resulting model. Through the implementation of an interior-point method constrained optimization technique, we improve the 2-D and 3-D models of Earth structures representing known density contrasts mapping anomalous bodies in uniform regions and boundaries between layers in layered environments. The proposed techniques are applied to synthetic data and gravitational data obtained from the Rio Grande Rift and the Cooper Flat Mine region located in Sierra County, New Mexico. Specifically, we improve the 2- and 3-D Earth models by getting rid of unacceptable solutions (those that do not satisfy the required constraints or are geologically unfeasible) given the reduction of the solution space.
De-tong Zhu
2009-01-01
In this paper we extend and improve the classical affine scaling interior-point Newton method for solving nonlinear optimization subject to linear inequality constraints in the absence of the strict complementar-ity assumption. Introducing a computationally efficient technique and employing an identification function for the definition of the new affine scaling matrix, we propose and analyze a new affine scaling interior-point Newton method which improves the Coleman and Li affine scaling matrix in [2] for solving the linear inequality con-strained optimization. Local superlinear and quadratical convergence of the proposed algorithm is established under the strong second order sufficiency condition without assuming strict complementarity of the solution.
张艺
2002-01-01
In this paper,a primal-dual interior point algorithm for convex quadratic progromming problem with box constrains is presented.It can be started at any primal-dual interior feasible point.If the initial point is close to the central path,it becomes a central path-following alogorithm and requires a total of O(√nL)number of iterations,where L is the input length.
A superquadratic infeasible-interior-point method for linear complementarity problems
Wright, S.; Zhang, Yin
1994-02-08
We consider a modification of a path-following infeasible-interior- point algorithm described by Wright. In the new algorithm, we attempt to improve each new iterate by reusing the coefficient matrix factors from the latest step. We show that the modified algorithm has similar theoretical global convergence properties to the earlier algorithm, while its asymptotic convergence rate can be made superquadratic by an appropriate parameter choice.
Unified Analysis of Kernel-Based Interior-Point Methods for P∗(κ)-Linear Complementarity Problems
Lesaja, G.; Roos, C.
2010-01-01
We present an interior-point method for the P∗(κ)-linear complementarity problem (LCP) that is based on barrier functions which are defined by a large class of univariate functions called eligible kernel functions. This class is fairly general and includes the classical logarithmic function and the
A Primal Dual Algorithm for a Heterogeneous Traveling Salesman Problem
Bae, Jungyun
2011-01-01
Surveillance applications require a collection of heterogeneous vehicles to visit a set of targets. In this article, we consider a fundamental routing problem that arises in these applications involving two vehicles. Specifically, we consider a routing problem where there are two heterogeneous vehicles that start from distinct initial locations, and a set of targets. The objective is to find a tour for each vehicle such that each of the targets is visited at least once by a vehicle and the sum of the distances traveled by the vehicles is a minimum. We present a primal-dual algorithm for a variant of this routing problem that provides an approximation ratio of 2.
A Primal-dual Neural Network for Shortest Path Problem
无
2002-01-01
The shortest path (SP) problem is a classical combinatorial optimization problem which plays an important role in a packet-switched computer and communication network. A new primal-dual neural network to solve the shortest path problem (PDSPN) is presented in this paper. The proposed neural network combines many features such as no network coefficients set,easy implementation in a VLSI circuit, and is proved to be completely stable to the exact solutions. The simulation example shows its efficiency in finding the "optimum" path(s) for data transmission in computer and communication network.
Z-Q. Luo; J.F. Sturm; S. Zhang (Shuzhong)
1996-01-01
textabstractThis paper establishes the superlinear convergence of a symmetric primal-dual path following algorithm for semidefinite programming under the assumptions that the semidefinite program has a strictly complementary primal-dual optimal solution and that the size of the central path neighbor
THE PRIMAL-DUAL POTENTIAL REDUCTION ALGORITHM FOR POSITIVE SEMI-DEFINITE PROGRAMMING
Si-ming Huang
2003-01-01
In this paper we introduce a primal-dual potential reduction algorithm for positivesemi-definite programming. Using the symetric preserving scalings for both primal anddual interior matrices, we can construct an algorithm which is very similar to the primal-dual potential reduction algorithm of Huang and Kortanek [6] for linear programming. Thecomplexity of the algorithm is either O(n log(X0 @ S0/ε) or O(√nlog(X0 @ S0/ε) dependson the value of ρ in the primal-dual potential function, where X0 and S0 is the initialinterior matrices of the positive semi-definite programming.
Khoshfetrat Pakazad, Sina; Hansson, Anders; Andersen, Martin S.;
2016-01-01
In this paper, we propose a distributed algorithm for solving coupled problems with chordal sparsity or an inherent tree structure which relies on primal–dual interior-point methods. We achieve this by distributing the computations at each iteration, using message-passing. In comparison to existing...... distributed algorithms for solving such problems, this algorithm requires far fewer iterations to converge to a solution with high accuracy. Furthermore, it is possible to compute an upper-bound for the number of required iterations which, unlike existing methods, only depends on the coupling structure...... in the problem. We illustrate the performance of our proposed method using a set of numerical examples....
Sokoler, Leo Emil; Frison, Gianluca; Edlund, Kristian
2013-01-01
In this paper, we develop an efficient interior-point method (IPM) for the linear programs arising in economic model predictive control of linear systems. The novelty of our algorithm is that it combines a homogeneous and self-dual model, and a specialized Riccati iteration procedure. We test...... the algorithm in a conceptual study of power systems management. Simulations show that in comparison to state of the art software implementation of IPMs, our method is significantly faster and scales in a favourable way....
Sokoler, Leo Emil; Skajaa, Anders; Frison, Gianluca
2013-01-01
algorithm in MATLAB and its performance is analyzed based on a smart grid power management case study. Closed loop simulations show that 1) our algorithm is significantly faster than state-of-the-art IPMs based on sparse linear algebra routines, and 2) warm-starting reduces the number of iterations......In this paper, we present a warm-started homogenous and self-dual interior-point method (IPM) for the linear programs arising in economic model predictive control (MPC) of linear systems. To exploit the structure in the optimization problems, our algorithm utilizes a Riccati iteration procedure...
Goran Lešaja
2011-02-01
Full Text Available We present an interior point method for Cartesian P*(k-Linear Complementarity Problems over Symmetric Cones (SCLCPs. The Cartesian P*(k-SCLCPs have been recently introduced as the generalization of the more commonly known and more widely used monotone SCLCPs. The IPM is based on the barrier functions that are defined by a large class of univariate functions called eligible kernel function which have recently been successfully used to design new IPMs for various optimization problems. Eligible barrier (kernel functions are used in calculating the Nesterov-Todd search directions and the default step-size which leads to a very good complexity results for the method. For some specific eligilbe kernel functions we match the best known iteration bound for the long-step methods while for the short-step methods the best iteration bound is matched for all cases.
Mohamed ACHACHE
2015-01-01
In this paper, we establish the polynomial complexity of a primal-dual path-following interior point algorithm for solving semidefinite optimization (SDO) problems. The proposed algorithm is based on a new kernel function which diff ers from the existing kernel functions in which it has a double barrier term. With this function we define a new search direction and also a new proximity function for analyzing its complexity. We show that if q1>q2>1, the algorithm has O((q1+1) n q1+1 2(q1−q2) log n? ) and O((q1+1) 3q1−2q2+12(q1−q2) √n log n? ) complexity results for large-and small-update methods, respectively.
Necoara, Ion; Clipici, Dragos N.; Olaru, Sorin
2013-01-01
Standard model predictive control strategies imply the online computation of control inputs at each sampling instance, which traditionally limits this type of control scheme to systems with slow dynamics. This paper focuses on distributed model predictive control for large-scale systems comprised of interacting linear subsystems, where the online computations required for the control input can be distributed amongst them. A model predictive controller based on a distributed interior point met...
On the chaotic behavior of the primal-dual affine-scaling algorithm for linear optimization.
Bruin, H; Fokkink, R; Gu, G; Roos, C
2014-12-01
We study a one-parameter family of quadratic maps, which serves as a template for interior point methods. It is known that such methods can exhibit chaotic behavior, but this has been verified only for particular linear optimization problems. Our results indicate that this chaotic behavior is generic.
Costa, Leandro L.H.; Silva, Alessandro L. da; Vergilio, Andre H.B.; Nepomuceno, Leonardo [Universidade Estadual Paulista (UNESP), Bauru, SP (Brazil). Dept. de Engenharia Eletrica], Emails: leandroluiz@ymail.com, alessandrolopessilva@uol.com.br, andrevergilio@yahoo.com.br, leo@feb.unesp.br; Cicogna, Marcelo Augusto [Anhanguera Educacional S.A. (Brazil)], E-mail: marcelo.cicogna@unianhanguera.edu.br,
2009-07-01
This paper aims to propose a model of economic dispatch for the problem representation of the auction in pool markets for systems with generation predominantly hydraulic. In the dispatch models described in the literature, only the agents of thermal generation participate in the auction pool. This is due to the fact that it have not been proposed in the literature yet a suitable model for representation of the cost structure of hydraulic generators. In this work is proposed the function of opportunity cost of hydrogeneration, which establishes a framework of 'cost' of hydraulic generation, based on losses in the process of hydroelectric generation. It is also studied the feasibility that both agents on the hydraulic and thermal generators can bidding in the pool. The approach to solving the problem involves the method of primal-dual logarithmic barrier. The results show that using the function of opportunity cost for hydroelectric plants is important for the system energy optimization as a whole, but its use for the representation of the bids of the hydraulic agents still needs further deepening search.
Zeng Ming
2013-09-01
Full Text Available Under the market environment of low carbon, whether renewable energy can obtain the power for sustainable development, promote the goal of the whole society and make money for investors depends on the rational optimization of power investment capacity and achieving power generation resources coordinated scheduling. This study constructs an expansion model of the generation capacity investment taking oligopoly, policy tools, carbon emissions trading right and green certificate system into account and uses the case analysis of the impact of ETS mechanism and the Tradable Green Certificate mechanism on power generation enterprises investment capacity with Newton KKT interior-point method. This study can also provide a strong decision basis for policy making.
2012-01-01
in the reservoir. A promising decrease of these remained resources can be provided by smart wells applying water injections to sustain satisfactory pressure level in the reservoir throughout the whole process of oil production. Basically to enhance secondary recovery of the remaining oil after drilling, water...... fields, or closed loop optimisation, can be used for optimising the reservoir performance in terms of net present value of oil recovery or another economic objective. In order to solve an optimal control problem we use a direct collocation method where we translate a continuous problem into a discrete...... for large scale nonlinear optimisation was applied. Because of its versatile compatibility with programming technologies, a C++ programming language in Microsoft Visual Studio integrated development environment was used for modelling the optimal control problem. Thanks to object oriented features...
A randomised primal-dual algorithm for distributed radio-interferometric imaging
Onose, Alexandru; McEwen, Jason D; Wiaux, Yves
2016-01-01
Next generation radio telescopes, like the Square Kilometre Array, will acquire an unprecedented amount of data for radio astronomy. The development of fast, parallelisable or distributed algorithms for handling such large-scale data sets is of prime importance. Motivated by this, we investigate herein a convex optimisation algorithmic structure, based on primal-dual forward-backward iterations, for solving the radio interferometric imaging problem. It can encompass any convex prior of interest. It allows for the distributed processing of the measured data and introduces further flexibility by employing a probabilistic approach for the selection of the data blocks used at a given iteration. We study the reconstruction performance with respect to the data distribution and we propose the use of nonuniform probabilities for the randomised updates. Our simulations show the feasibility of the randomisation given a limited computing infrastructure as well as important computational advantages when compared to state...
Syam Syafiie
2014-06-01
Full Text Available A comparative study of Model Predictive Control (MPC using active-set method and interior point methods is proposed as a control technique for highly non-linear pH process. The process is a strong acid-strong base system. A strong acid of hydrochloric acid (HCl and a strong base of sodium hydroxide (NaOH with the presence of buffer solution sodium bicarbonate (NaHCO3 are used in a neutralization process flowing into reactor. The non-linear pH neutralization model governed in this process is presented by multi-linear models. Performance of both controllers is studied by evaluating its ability of set-point tracking and disturbance-rejection. Besides, the optimization time is compared between these two methods; both MPC shows the similar performance with no overshoot, offset, and oscillation. However, the conventional active-set method gives a shorter control action time for small scale optimization problem compared to MPC using IPM method for pH control.
杨轶华; 吕显瑞; 刘庆怀
2006-01-01
In this paper, on the basis of the logarithmic barrier function and KKT conditions, we propose a combined homotopy infeasible interior-point method (CHIIP)for convex nonlinear programming problems. For any convex nonlinear programming,without strict convexity for the logarithmic barrier function, we get different solutions of the convex programming in different cases by CHIIP method.
Penalized interior point approach for constrained nonlinear programming
LU Wen-ting; YAO Yi-rong; ZHANG Lian-sheng
2009-01-01
A penalized interior point approach for constrained nonlinear programming is examined in this work. To overcome the difficulty of initialization for the interior point method, a problem equivalent to the primal problem via incorporating an auxiliary variable is constructed. A combined approach of logarithm barrier and quadratic penalty function is proposed to solve the problem. Based on Newton's method, the global convergence of interior point and line search algorithm is proven.Only a finite number of iterations is required to reach an approximate optimal solution. Numerical tests are given to show the effectiveness of the method.
A method for weighted projections to the positive definite cone
Valkonen, Tuomo
2014-06-24
© 2014 Taylor & Francis. We study the numerical solution of the problem (Formula presented.) , where (Formula presented.) is a symmetric square matrix, and (Formula presented.) is a linear operator, such that (Formula presented.) is invertible. With (Formula presented.) the desired fractional duality gap, and (Formula presented.) the condition number of (Formula presented.) , we prove (Formula presented.) iteration complexity for a simple primal-dual interior point method directly based on those for linear programs with semi-definite constraints. We do not, however, require the numerically expensive scalings inherent in these methods to force fast convergence. For low-dimensional problems (Formula presented.), our numerical experiments indicate excellent performance and only a very slowly growing dependence of the convergence rate on (Formula presented.). While our algorithm requires somewhat more iterations than existing interior point methods, the iterations are cheaper. This gives better computational times.
Pham, Mai Quyen; Chaux, Caroline; Pesquet, Jean-Christophe
2014-01-01
Unveiling meaningful geophysical information from seismic data requires to deal with both random and structured "noises". As their amplitude may be greater than signals of interest (primaries), additional prior information is especially important in performing efficient signal separation. We address here the problem of multiple reflections, caused by wave-field bouncing between layers. Since only approximate models of these phenomena are available, we propose a flexible framework for time-varying adaptive filtering of seismic signals, using sparse representations, based on inaccurate templates. We recast the joint estimation of adaptive filters and primaries in a new convex variational formulation. This approach allows us to incorporate plausible knowledge about noise statistics, data sparsity and slow filter variation in parsimony-promoting wavelet frames. The designed primal-dual algorithm solves a constrained minimization problem that alleviates standard regularization issues in finding hyperparameters. Th...
A New Primal-Dual Polynomial Algorithm for Convex Quadratic Programming%一种新的求解凸二次规划的原始-对偶多项式内点算法
龚小玉; 胡振鹏; 王先甲
2012-01-01
In this paper,we present a new primal-dual path-following method to solve the convex quadratic programming. The new method is based on a technique for finding the search directions not different to the classical Newton method. At last,we prove that the algorithm has polynomial-time complexity.%对凸二次规划问题提出了一种新的原始-对偶路径跟踪算法,算法迭代方向的求解是不同于传统的牛顿法,而是借助于一种新的工具找到搜寻方向.最后证明了算法具有多项式复杂性.
李鑫
2016-01-01
Based on a new class of kernel functions,a large-update primal-dual interior-point algorithm for convex quadratic programming is presented.By using new technical results and favorable properties of the kernel function, the study proves that the iteration complexity for the algorithm is On1/2lognlogn/ε, which is identical with the currently best iteration bound for large-update primal-dual interior-point algorithms of convex quadratic programming.%基于一类新的核函数对凸二次规划(CQP)设计了一种大步校正内点算法。通过应用新的技术性结果和这类核函数良好的性质，证明了算法的迭代复杂性为 O(n1/2lognlogn/ε)，这与目前凸二次规划的大步校正原始-对偶内点算法最好的迭代复杂性一致。
A POSITIVE INTERIOR-POINT ALGORITHM FOR NONLINEAR COMPLEMENTARITY PROBLEMS
马昌凤; 梁国平; 陈新美
2003-01-01
A new iterative method, which is called positive interior-point algorithm, is presented for solving the nonlinear complementarity problems. This method is of the desirable feature of robustness. And the convergence theorems of the algorithm is established. In addition, some numerical results are reported.
Interior point algorithms theory and analysis
Ye, Yinyu
2011-01-01
The first comprehensive review of the theory and practice of one of today's most powerful optimization techniques. The explosive growth of research into and development of interior point algorithms over the past two decades has significantly improved the complexity of linear programming and yielded some of today's most sophisticated computing techniques. This book offers a comprehensive and thorough treatment of the theory, analysis, and implementation of this powerful computational tool. Interior Point Algorithms provides detailed coverage of all basic and advanced aspects of the subject.
Some Geometric Inequalities Relating to an Interior Point in Triangle
Wu, Yu-Dong; Zhang, Zhi-Hua; Liang, Chun-Lei
2010-01-01
In this short note, by using one of Li and Liu's theorems [K.-H. Li, "The solution of CIQ. 39," "Commun. Stud. Inequal." 11(1) (2004), p. 162 (in Chinese)], "s-R-r" method, Cauchy's inequality and the theory of convex function, we solve some geometric inequalities conjectures relating to an interior point in triangle. (Contains 1 figure.)
李鑫; 季萍; 张明望
2015-01-01
In this paper, we propose a new full-Newton step primal-dual interior-point algorithm for solving convex quadratic semi-definite programming. By establishing and using new technical results, we show that the iteration complexity of algorithm asO(nlogn)ε is as good as the currently best iteration complexity for small-update interior-point algorithms of convex quadratic semi-definite programming.%对凸二次半定规划提出了一种新的全-Newton步原始-对偶内点算法.通过建立和应用一些新的技术性结果,证明了算法的迭代复杂性为O( n log n )ε ,这与目前凸二次半定规划的小步校正内点算法最好的迭代复杂性一致.
Ad Hoc Microphone Array Beamforming Using the Primal-Dual Method of Multipliers
Tavakoli, Vincent Mohammad; Jensen, Jesper Rindom; Heusdens, Richard
2016-01-01
In the recent years, there have been increasing amount of researches aiming at optimal beamforming with ad hoc microphone arrays, mostly with fusion-based schemes. However, huge amount of computational complexity and communication overhead impede many of these algorithms from being useful...
Jesús María López Lezama
2008-12-01
Full Text Available This paper presents a lineal optimization model to solve the hydrothermal coordination problem. The main contribution of this work is the inclusion of the network constraints to the hydrothermal coordination problem and its solution using an interior point method. The proposed model allows working with a system that can be completely hydraulic, thermal or mixed. Results are presented on the IEEE 14 bus test system.En este artículo se presenta un modelo de optimización lineal para resolver el problema de la coordinación hidrotérmica. El principal aporte de este trabajo es la inclusión de las restricciones de red al problema de coordinación hidrotérmica y su solución usando un método de punto interior. El modelo propuesto permite manejar un sistema completamente hídrico, completamente térmico o un sistema mixto. Se presentan resultados para el sistema de prueba IEEE de 14 barras.
朱德通
2004-01-01
A interior point scaling projected reduced Hessian method with combination of nonmonotonic backtracking technique and trust region strategy for nonlinear equality constrained optimization with nonegative constraint on variables is proposed.In order to deal with large problems,a pair of trust region subproblems in horizontal and vertical subspaces is used to replace the general full trust region subproblem.The horizontal trust region subproblem in the algorithm is only a general trust region subproblem while the vertical trust region subproblem is defined by a parameter size of the vertical direction subject only to an ellipsoidal constraint.Both trust region strategy and line search technique at each iteration switch to obtaining a backtracking step generated by the two trust region subproblems.By adopting the l1 penalty function as the merit function, the global convergence and fast local convergence rate of the proposed algorithm are established under some reasonable conditions.A nonmonotonic criterion and the second order correction step are used to overcome Maratos effect and speed up the convergence progress in some ill-conditioned cases.
张艺
2004-01-01
对具有线性约束凸二次规划问题给出了一个原始-对偶内点算法,任一原始-对偶可行内点都可作为算法的初始点,当初始点在中心路径附近时,便成为中心路径跟踪算法,此时总迭代次数为0( nL),其中L为输入长度.数值实验表明,算法对求解大型的这类问题是有效的.
陈飞翔; 张辉; 武忠祥
2009-01-01
在线性规划原始对偶内点算法的基础上,进一步给出原始对偶内点算法在解凸二次规划问题中的应用, 并初步给出了该算法的数值例子, 作为对内点算法的一个重要补充.
Simulation of superconducting tapes and coils with convex quadratic programming method
Zhang, Yan; Song, Yuntao; Wang, Lei; Liu, Xufeng
2015-08-01
Second-generation (2G) high-temperature superconducting coated conductors are playing an increasingly important role in power applications due to their large current density under high magnetic fields. In this paper, we conclude and explore the ability and possible potential of J formulation from the mathematical modeling point of view. An equivalent matrix form of J formulation has been presented and a relation between electromagnetic quantities and Karush-Kuhn-Tucker (KKT) conditions in optimization theory has been discovered. The use of the latest formulae to calculate inductance in a coil system and the primal-dual interior-point method algorithm is a trial to make the process of modeling stylized and build a bridge to commercial optimization solvers. Two different dependences of the critical current density on the magnetic field have been used in order to make a comparison with those published papers.
高沁; 卫志农; 陈洪涛; 孙国强; 孙永辉
2015-01-01
In the large-scale optimal power flow (OPF) online calculation,despite the highly efficient computation of the traditional direct current optimal power flow(DCOPF)method,it has poor computational accuracy owing to its total neglect of the impact of voltage and reactive power.A novel OPF method based on the pseudo direct current model is proposed,in which reactive power is introduced to correct active power balance equations.To further increase the computational efficiency,a simplified predictor-corrector interior point method,which predigests the program by modifying the inequality constraints of the OPF model,is used to solve the OPF problem.Finally,it follows from the simulation results of IEEE 30-bus,1 18-bus, 300-bus, Polish 2 736-bus, and 3 120-bus test systems that the proposed method is successful and possesses good performance.%在大规模电力系统最优潮流的在线计算应用中,传统直流最优潮流算法虽然有着很高的计算效率,但是由于其完全忽略了电压和无功功率的影响,计算结果精度偏低。文中通过引入无功功率来修正有功功率平衡方程,提出了基于拟直流模型的最优潮流算法。为进一步提高计算效率,提出了一种简化预测—校正内点算法,该算法通过对最优潮流模型中不等式约束进行简化处理,形成只含上限约束的广义不等式约束,大大简化了程序的编写。通过对 IEEE 30,118,300节点系统以及 Polish 2736,3120节点系统的仿真测试,验证了算法的可行性和有效性。
The Homogeneous Interior-Point Algorithm: Nonsymmetric Cones, Warmstarting, and Applications
Skajaa, Anders
algorithms for these problems is still limited. The goal of this thesis is to investigate and shed light on two computational aspects of homogeneous interior-point algorithms for convex conic optimization: The first part studies the possibility of devising a homogeneous interior-point method aimed at solving...... problems involving constraints that require nonsymmetric cones in their formulation. The second part studies the possibility of warmstarting the homogeneous interior-point algorithm for conic problems. The main outcome of the first part is the introduction of a completely new homogeneous interior......-point algorithm designed to solve nonsymmetric convex conic optimization problems. The algorithm is presented in detail and then analyzed. We prove its convergence and complexity. From a theoretical viewpoint, it is fully competitive with other algorithms and from a practical viewpoint, we show that it holds lots...
何姣姣; 庹谦; 周震; 陈剑鸣
2016-01-01
图像在采集、存储、传输以及显示过程中，由于各种因素，往往会造成图像模糊，所以消除图像中的噪声、去除模糊等意义重大。在模糊图像恢复过程中，运用针对 Tikhonov 正则化问题演化来的梯度下降法与原-对偶算法，以及它们改进的算法对模糊图像进行恢复。在这一模型中，正则化参数的选择对图像恢复的效果有很大的影响，选取一个相对合适的正则化参数来平衡拟合项与正则项情况很重要。选定合适的正则化参数后，在 Armijo 准则下应用0.618优选法选择步长，进行梯度下降法以及正则化下的原-对偶算法的计算，对模糊灰度图像进行恢复。使用上述2种方法对模糊图像进行恢复，实验表明，与梯度下降法相较而言，原-对偶算法在图像恢复中效果更好。%In the process of collection,storage,transmission and display of image,it often has blurring due to various factors,so to eliminate the noise in the image and remove the fuzzy is of great significance.In the process of blur image res-toration,the gradient decent method with the primal-dual algorithm and improved algorithm evolved by Tikhonov regulariza-tion problem are used to recover the image.In this model,the choice of regularization parameter has a great influence on the effect of image restoration,and it is very important to select a relatively suitable regularization parameter to balance the fit-ting term and regularization term.After selecting the appropriate regularization parameter,the gradient descent method and the primal dual algorithm are applied in the Armijo criteria,and the fuzzy gray image is restored by using the gradient de-scent method and the normalized algorithm.Two methods are used to restore the blurred image.The experiments show that the original dual algorithm is better than the gradient descent method in image restoration.
Deconvolution of interferometric data using interior point iterative algorithms
Theys, C.; Lantéri, H.; Aime, C.
2016-09-01
We address the problem of deconvolution of astronomical images that could be obtained with future large interferometers in space. The presentation is made in two complementary parts. The first part gives an introduction to the image deconvolution with linear and nonlinear algorithms. The emphasis is made on nonlinear iterative algorithms that verify the constraints of non-negativity and constant flux. The Richardson-Lucy algorithm appears there as a special case for photon counting conditions. More generally, the algorithm published recently by Lanteri et al. (2015) is based on scale invariant divergences without assumption on the statistic model of the data. The two proposed algorithms are interior-point algorithms, the latter being more efficient in terms of speed of calculation. These algorithms are applied to the deconvolution of simulated images corresponding to an interferometric system of 16 diluted telescopes in space. Two non-redundant configurations, one disposed around a circle and the other on an hexagonal lattice, are compared for their effectiveness on a simple astronomical object. The comparison is made in the direct and Fourier spaces. Raw "dirty" images have many artifacts due to replicas of the original object. Linear methods cannot remove these replicas while iterative methods clearly show their efficacy in these examples.
Dollerup, Niels; Jepsen, Michael S.; Frier, Christian;
2014-01-01
A robust and effective finite element based implementation of lower bound limit state analysis applying an interior point formulation is presented in this paper. The lower bound formulation results in a convex optimization problem consisting of a number of linear constraints from the equilibrium...... equations and a number of convex non-linear constraints from the yield criteria. The computational robustness has been improved by eliminating a large number of the equilibrium equations a priori leaving only the statical redundant variables as free optimization variables. The elimination of equilibrium...... equations is based on a optimized numbering of elements and stress variables based on the frontal method approach used in the standard finite element method. The optimized numbering secures sparsity in the formulation. The convex non-linear yield criteria are treated directly in the interior point...
Interior point algorithm for linear programming used in transmission network synthesis
Sanchez, I.G.; Romero, R.; Mantovani, J.R.S. [Electrical Engineering Department, UNESP, CEP 15385000, Ilha Solteira, SP (Brazil); Garcia, A. [Power Systems Department, University of Campinas, UNICAMP, CEP 13083970, Campinas, SP (Brazil)
2005-09-15
This article presents a well-known interior point method (IPM) used to solve problems of linear programming that appear as sub-problems in the solution of the long-term transmission network expansion planning problem. The linear programming problem appears when the transportation model is used, and when there is the intention to solve the planning problem using a constructive heuristic algorithm (CHA), or a branch-and-bound algorithm. This paper shows the application of the IPM in a CHA. A good performance of the IPM was obtained, and then it can be used as tool inside algorithms used to solve the planning problem. Illustrative tests are shown, using electrical systems known in the specialized literature. (author) [Transmission network synthesis; Interior point method; Relaxed optimization models; Network expansion planning; Transportation model; Constructive heuristic algorithms].
A superlinear interior points algorithm for engineering design optimization
Herskovits, J.; Asquier, J.
1990-01-01
We present a quasi-Newton interior points algorithm for nonlinear constrained optimization. It is based on a general approach consisting of the iterative solution in the primal and dual spaces of the equalities in Karush-Kuhn-Tucker optimality conditions. This is done in such a way to have primal and dual feasibility at each iteration, which ensures satisfaction of those optimality conditions at the limit points. This approach is very strong and efficient, since at each iteration it only requires the solution of two linear systems with the same matrix, instead of quadratic programming subproblems. It is also particularly appropriate for engineering design optimization inasmuch at each iteration a feasible design is obtained. The present algorithm uses a quasi-Newton approximation of the second derivative of the Lagrangian function in order to have superlinear asymptotic convergence. We discuss theoretical aspects of the algorithm and its computer implementation.
A superlinear interior points algorithm for engineering design optimization
Herskovits, J.; Asquier, J.
1990-01-01
We present a quasi-Newton interior points algorithm for nonlinear constrained optimization. It is based on a general approach consisting of the iterative solution in the primal and dual spaces of the equalities in Karush-Kuhn-Tucker optimality conditions. This is done in such a way to have primal and dual feasibility at each iteration, which ensures satisfaction of those optimality conditions at the limit points. This approach is very strong and efficient, since at each iteration it only requires the solution of two linear systems with the same matrix, instead of quadratic programming subproblems. It is also particularly appropriate for engineering design optimization inasmuch at each iteration a feasible design is obtained. The present algorithm uses a quasi-Newton approximation of the second derivative of the Lagrangian function in order to have superlinear asymptotic convergence. We discuss theoretical aspects of the algorithm and its computer implementation.
Arc-Search Infeasible Interior-Point Algorithm for Linear Programming
Yang, Yaguang
2014-01-01
Mehrotra's algorithm has been the most successful infeasible interior-point algorithm for linear programming since 1990. Most popular interior-point software packages for linear programming are based on Mehrotra's algorithm. This paper proposes an alternative algorithm, arc-search infeasible interior-point algorithm. We will demonstrate, by testing Netlib problems and comparing the test results obtained by arc-search infeasible interior-point algorithm and Mehrotra's algorithm, that the propo...
HE; Shanglu
2001-01-01
［1］Andersen, E. D., Ye, Y., On homogeneous algorithm for the monotone complementarity problem, Mathematical Programming, 1999, 84(2): 375.［2］Wright, S., Ralph, D., A supperlinear infeasible-interior-point algorithm for monotone complementarity problems, Mathematics of Operations Research, 1996, 24(4): 815.［3］Kojima, M., Noma, T., Yoshise, A., Global convergence in infeasible-interior-point algorithms, Mathematical Programming, 1994, 65(1): 43.［4］Kojima, M., Megiddo, N., Noma, T., A new continuation method for complementarity problems with uniform p-functions, Mathematical Programming, 1989, 43(1): 107.［5］Kojima, M., Megiddo, N., Mizuno, S., A general framework of continuation method for complementarity problems, Mathematics of Operations Research, 1993, 18(4): 945.［6］More, J., Rheinboldt, W., On P- and S-functions and related classes of n-dimensional nonlinear mappings, Linear Algebra and Its Applications, 1973, 6(1): 45.
房亮; 贺国平; 王永丽
2011-01-01
In this paper, nonlinear complementarity problem with Po0function is studied.Based on a new smoothing function, the problem is approximated by a family of parameterized smooth equations and a new non-interior-point continuation method is presented for solving it. At each iteration, the proposed algorithm only need to solve a system of linear equations and perform only one Armijo-type line search. The algorithm is proved to be globally as well as locally superlinearly convergent without strict complementarity. Moreover, the quadratic convergence rate can be achieved under mild conditions. Numerical experiments demonstrate the feasibility and efficiency of the new algorithm.%研究带有P0函数的非线性互补问题.基于一个新的光滑函数,把问题近似成参数化的光滑方程组,并且给出一个新的非内点连续算法.所给算法在每步迭代只需要求解一个线性方程组和执行一次Armijo类型的线搜索.在不需要严格互补条件的情况下,证明了算法是全局收敛和超线性收敛的.并且,在一个较弱的条件下该算法具有局部二阶收敛性.数值实验证实了算法的可行性和有效性.
SOLVING CONVEX QUADRATIC PROGRAMMING BY POTENTIAL-REDUCTION INTERIOR-POINT ALGORITHM
无
2001-01-01
The solution of quadratic programming problems is an importantissue in the field of mathematical programming and industrial applications. In this paper, we solve convex quadratic programming by a potential-reduction interior-point algorithm. It is proved that the potential-reduction interior-point algorithm is globally convergent. Some numerical experiments were made.
简金宝; 杨林峰; 全然
2012-01-01
This paper presents a new parallel algorithm to solve dynamic optimal power flow （DOPF） based on the methods of improved multiple centrality corrections （MCC） and decoupling. A parallel decoupling-factorization-substitution method for the correction equation of DOPF is proposed by integrating interior point method （IPM） framework and the block arrow correction equation, and then, the methods of dynamic increasing step length and adaptive corrections are given. A longer iteration step length and a better central point, which can be obtained by the proposed algorithm, give on the reduction in the number of iterations and savings in computing time than IPM. Most of operations in proposed method can be processed in parallel with decoupling. The sequential simulation results for systems that range in size from 6 to 118 buses show that the proposed method is fast and robust, and the simulations in multi-core cluster show that the method is very promising for large scale DOPF problems due to its excellent speed up and scalability.%基于改进的多中心校正（MCC）和解耦技术,提出一种求解动态最优潮流（DOPF）的并行算法。结合内点算法（IPM）框架与DOPF修正方程的分块箭形结构,给出修正方程的并行解耦-分解-回代解法。并结合这一解法特点,提出动态步长拉大技术及自适应最大校正次数技术,以单次迭代计算量小幅增加为代价,换取迭代步长的增大,迭代点中心性的提高,总迭代次数和计算时间的显著减少。解耦技术的使用,使得所提算法的核心计算都可并行完成。6～118节点系统的串行仿真结果表明,算法具有很好的鲁棒性和收敛速度,在多核集群系统上的并行仿真表明,算法具有理想的加速比和可扩放性,适合求解大规模的DOPF问题。
Neighborhood-following algorithms for linear programming
无
2004-01-01
［1］Kojima, M., Mizuno, S., Yoshise, A., A polynomial-time algorithm for a class of linear complementarity probems, Mathematical Programming, 1989, 44: 1-26.［2］Megiddo, N., Pathways to the optimal set in linear programming. in Progression Mathematical Programming:Interior Point and Related Methods, New York: Springer-Verlag, 1989, 131-158.［3］Monteiro, R. D. C., Adler, I., Interior path following primal-dual algorithms, Part Ⅰ: linear programming, Mathematical Programming, 1989, 44: 27-41.［4］Monteiro, R. D. C., Adler, I., Interior path following primal-dual algorithms, Part Ⅱ: convex quadratic programming, Mathematical Programming, 1989, 44: 43-46.［5］Wright, S. J., Primal-Dual Interior-Point Methods, Philadephia: SIAM Publications, 1997.［6］Mizuno, S., Todd, M. J., Ye, Y., On adaptive step primal-dual interior-point algorithms for linear programming,Mathematics of Operations Research, 1993, 18:964-981.［7］Gonzaga, C. C., The largest step path following algorithm for monotone linear complementarity problems, Mathematical Programming, 1997, 76: 309-332.［8］Sturm, J. F., Zhang, S., On a wide region of centers primal-dual interior point algorithms for linear programming,Tinbergen Institute Rotterdam, Erasmus University, Rotterdam, The Netherlands, 1995.［9］Hung, P., Ye, Y., An asymptotical O(√nL)-iteration path-following linear programming algorithm that uses wide neighborhoods, SIAM J.Optimization, 1996, 6: 570-586.［10］Ye, Y., Interior Point Algorithms: Theory and Analysis, New York: Wiley-Interscience Publication, 1997.［11］Güler, O., Ye, Y., Convergence behavior of interior-point algorithms. Mathematical Programming, 1993, 60:215-228.［12］Mehrotral, S., On the implementation of a primal-dual interior point mehtod, SIAM J. Optimization, 1992, 2(4):575-601.
刘新东; 陈焕远
2012-01-01
目前分布式电网的潮流优化算法主要面对三相功率平衡系统,对于三相不平衡系统进行分析的算法介绍较少.文中利用内点法,结合美国电科院的开放式配电仿真系统分析(OpenDSS)平台,提出了三相不平衡分布式电网潮流优化算法的研究.该算法以网损和变压器三相潮流不平衡度量小为目标,以系统潮流、发电机和线路极限容量为约束,以变压器分接头和电容器投切为控制变量,建立了优化函数,利用内点法作为优化算法,以OPenDSS为计算平台.文中最后以IEEE123测试节点和IEEE9500测试节点为例,验证了文中算法的有效性和实用性.%Optimal power flow methods were mainly designed lo solve balanced three-phase dislribuleti system. Little of them could be applied to unbalanced three-phase distributed system. A method of unbalanced three-phase optimal power flow for distributed system is present in the paper,based on EPRI's open source project OpenDSS and interior point method. The method employs maximization of energy louses and unbalance level of transformers,suhjeel lo meeting power (low,capacity of generator and lines, with transformer lap and capacitor switching as control variable,utilize interior and OpenDSS as compute platform. Taking the 1EEEI23 and 1EEE9500 test systems as example,the effective and practical of (he method is proved.
徐青山; 曾艾东; 王凯; 蒋菱
2016-01-01
微型能源网包含冷、热、电和气4种能源形式，具有负荷种类多样、供能设备丰富的特点。在对微型能源网内多种供能及蓄能设备进行建模的基础上，提出基于集中互连能源交换网络的冷热电联供微型能源网的供能架构，架构内冷热电负荷被细分为纯电负荷、热水负荷、空间热负荷、冷冻制冷负荷和空间冷负荷，围绕该架构建立冷热电联供微型能源网经济优化调度模型，采用基于Hessian矩阵迭代的内点法对模型进行了求解。算例表明，通过调度微型能源网内各供能设备的运行方式和出力，可以显著降低系统的日运行费用，实现冷热电联供微型能源网的经济优化运行，得出的合理调度方案证实了所提模型和求解方法的正确性及有效性。%Micro energy-grid contains four forms of energy: cold, heat,electricity and gas, possessing features of diversified load forms and energy supply devices. After modeling of a variety of energy supply and storage devices, this paper proposed an energy supply infrastructure for combined cooling heating and power (CCHP)-based micro energy-grid based on centralized and interconnected energy exchange network. Loads are subdivided into pure electricity, hot water, space heating, refrigeration and space cooling. Optimized economic dispatching model of CCHP-based micro energy-grid is established according to the infrastructure. The model is solved with interior point method with Hessian matrix iteration. Study case shows that the dispatching method can achieve optimized economic operation of micro energy-grid by reducing operation cost remarkably through controlling operation mode and output of energy supply and storage equipment. Rational dispatching method confirms correctness and validity of the proposed model and solving method.
沈忠环; 张明望; 赵玉琴
2009-01-01
基于线性规划原始-对偶势下降内点算法的思想,对框式凸二次规划提出一种新的内点算法宽邻域原始-对偶势下降内点算法.算法选取牛顿方向作为迭代方向,利用势函数选择迭代步长,分析算法的多项式迭代复杂性,并证明新算法具有较好的迭代复杂性O(nL).
Sokoler, Leo Emil; Frison, Gianluca; Skajaa, Anders
2015-01-01
We develop an efficient homogeneous and self-dual interior-point method (IPM) for the linear programs arising in economic model predictive control of constrained linear systems with linear objective functions. The algorithm is based on a Riccati iteration procedure, which is adapted to the linear...... is significantly faster than several state-of-the-art IPMs based on sparse linear algebra, and 2) warm-start reduces the average number of iterations by 35-40%.......We develop an efficient homogeneous and self-dual interior-point method (IPM) for the linear programs arising in economic model predictive control of constrained linear systems with linear objective functions. The algorithm is based on a Riccati iteration procedure, which is adapted to the linear...
叶蕾; 杨震; 王天荆; 孙林慧
2012-01-01
基于语音信号在离散余弦域上的近似稀疏性,针对采用随机高斯观测矩阵及线性规划方法进行语音压缩感知与重构时,重构零(近似零)系数定位能力差而导致重构效果不好的缺点,本文提出一种新的行阶梯矩阵做观测矩阵,用对偶仿射尺度内点重构算法对语音进行压缩感知与重构,并对该算法下的重构性能进行理论分析.语音压缩感知仿真结果表明,在离散余弦基下,压缩比(观测序列与原始序列样值数之比)为1∶4时,行阶梯观测矩阵下的平均重构信噪比比随机高斯观测矩阵下提高9.73dB,平均MOS分比随机高斯观测矩阵下提高1.22分.%Based on the approximate sparsity of speech signal in discrete cosine basis, this paper proposes a new algorithm of compressed sensing of speech signal based on special row echelon measurement matrix and dual affine scaling interior point re-construction method, This algorithra can resolve the problem of inaccuracy of location of reconstruction coefficient which is zero ornearly zero of compressed sensing based on Caussian measurement matrix and linear programming to some extent. The reconstruc-tion performance of this algorithm is analyzed theoretically. The simulation results of compressed sensing of speech signal showwhen the reduction ratio(the ratio of numbers of measurements and original samples) is 1:4 based on the discrete cosine basis,theaverage SNR of reconsm~on signal based on the special row echelon measurement matrix is 9.73 dB higher than the Gaussianmeasurement matrix,and the average MOS score of reconstruction signal based on the special row echelon measurement matrix is1.22 higher than the Gaussian measurement matrix.
A Note on the Existence of a Specified Number of Interior Points
WEI Xiang-lin; DING Ren
2012-01-01
An interior point of a finite planar point set is a point of the set that is not on the boundary of the convex hull of the set.For any integer k ≥ 1,let h(k) be the smallest integer such that every set of points in the plane,no three collinear,with at least h(k) interior points,has a subset of points with exactly k or k + 1 interior points of P.We prove that h(5) =11.
Solving semi-infinite optimization problems with interior point techniques
Stein, Oliver; Still, Georg
2003-01-01
We introduce a new numerical solution method for semi-infinite optimization problems with convex lower level problems. The method is based on a reformulation of the semi-infinite problem as a Stackelberg game and the use of regularized nonlinear complementarity problem functions. This approach leads
Solving semi-infinite optimization problems with interior point techniques
Stein, Oliver; Still, Georg J.
2003-01-01
We introduce a new numerical solution method for semi-infinite optimization problems with convex lower level problems. The method is based on a reformulation of the semi-infinite problem as a Stackelberg game and the use of regularized nonlinear complementarity problem functions. This approach leads
无
2001-01-01
This paper presents an infeasible-interior-point algorithm for aclass of nonmonotone complementarity problems, and analyses its convergence and computational complexity. The results indicate that the proposed algorithm is a polynomial-time one.
AN INFEASIBLE-INTERIOR-POINT PREDICTOR-CORRECTOR ALGORITHM FOR THE SECOND-ORDER CONE PROGRAM
Chi Xiaoni; Liu Sanyang
2008-01-01
A globally convergent infeasible-interior-point predictor-corrector algorithm is presented for the second-order cone programming (SOCP) by using the Alizadeh-Haeberly-Overton (AHO) search direction. This algorithm does not require the feasibility of the initial points and iteration points. Under suitable assumptions, it is shown that the algorithm can find an c-approximate solution of an SOCP in at most O(√nln(∈0/∈)) iterations. The iteration-complexity bound of our algorithm is almost the same as the best known bound of feasible interior point algorithms for the SOCP.
ON INTERIOR POINTS OF THE JULIA SET J（R） FOR RANDOM DYNAMICAL SYSTEM R
GONGZHIMIN; RENFUYAO
1997-01-01
The authors consider the random iteration of serval functions. Denote by J(R) the Julia set for the random iteration dynamical system formed by a set of complex functions R ={R1,R2,…, RM}. Some sufficient conditions axe given for J(R) to have no interior points.Also some conditions are given for J(R) to have interior points but fail to be the extendedplane. In addition, J(azn,bzn) (n ≥ 2,ab ≠ O) and J(z2+c1,x2+c2) are investigated and some interesting results are obtained.
EXPECTED NUMBER OF ITERATIONS OF INTERIOR-POINT ALGORITHMS FOR LINEAR PROGRAMMING
Si-ming Huang
2005-01-01
We study the behavior of some polynomial interior-point algorithms for solving random linear programming (LP) problems. We show that the expected and anticipated number of iterations of these algorithms is bounded above by O(n1,5). The random LP problem is Todd's probabilistic model with the Cauchy distribution.
Average number of iterations of some polynomial interior-point--Algorithms for linear programming
无
2000-01-01
We study the behavior of some polynomial interior-point algorithms for solving random linear programming (LP) problems. We show that the average number of iterations of these algorithms, coupled with a finite termination technique, is bounded above by O(n1.5). The random LP problem is Todd's probabilistic model with the standard Gauss distribution.
Integrated Approaches to Parallelism in Optimization and the Solution of Inverse Problems
1992-09-30
Aplicadas y Primera Escuela , Chile - CEE de Optimizaci6n; Santiago, Chile; August 28, 1992 - September 6, 1992. * "On Alternative Problem...the Iteration Sequence in Primal-Dual Interior-Point Methods for Linear Programming," Fourth SIAM Conference on Optimization; Chicago , Illinois; May
Probabilistic structural analysis by extremum methods
Nafday, Avinash M.
1990-01-01
The objective is to demonstrate discrete extremum methods of structural analysis as a tool for structural system reliability evaluation. Specifically, linear and multiobjective linear programming models for analysis of rigid plastic frames under proportional and multiparametric loadings, respectively, are considered. Kinematic and static approaches for analysis form a primal-dual pair in each of these models and have a polyhedral format. Duality relations link extreme points and hyperplanes of these polyhedra and lead naturally to dual methods for system reliability evaluation.
Bougeard, M. L.
In recent years, robustness is one problem that has been given much attention in statistical literature. While it is now clear that no single robust regression procedure is best, the L1 and the Huber-M estimators are currently attracting a considerable attention when the errors have a contaminated Gaussian distribution. Nevertheless, they cannot be expressed analytically. So, finding efficient algorithms to produce them in the case of large data sets is still a field of active research. In this paper, the author first discusses the early contribution of Laplace and others to the L1 problem. Then, he presents new algorithms based on the Spingarn Partial Inverse-proximal approach that takes into account both primal and dual aspects of the M-estimation problem. It is shown how the method can be easily extended to handle constrained problems. The result is a family of highly parallel algorithms attractive for large scale problems. Astrometrical applications are considered.
ZHU Detong
2006-01-01
In this paper,we propose a new trust-region-projected Hessian algorithm with nonmonotonic backtracking interior point technique for linear constrained optimization.By performing the QR decomposition of an affine scaling equality constraint matrix,the conducted subproblem in the algorithm is changed into the general trust-region subproblem defined by minimizing a quadratic function subject only to an ellipsoidal constraint.By using both the trust-region strategy and the line-search technique,each iteration switches to a backtracking interior point step generated by the trustregion subproblem.The global convergence and fast local convergence rates for the proposed algorithm are established under some reasonable assumptions.A nonmonotonic criterion is used to speed up the convergence in some ill-conditioned cases.
A POLYNOMIAL PREDICTOR-CORRECTOR INTERIOR-POINT ALGORITHM FOR CONVEX QUADRATIC PROGRAMMING
Yu Qian; Huang Chongchao; Jiang Yan
2006-01-01
This article presents a polynomial predictor-corrector interior-point algorithm for convex quadratic programming based on a modified predictor-corrector interior-point algorithm. In this algorithm, there is only one corrector step after each predictor step,where Step 2 is a predictor step and Step 4 is a corrector step in the algorithm. In the algorithm, the predictor step decreases the dual gap as much as possible in a wider neighborhood of the central path and the corrector step draws iteration points back to a narrower neighborhood and make a reduction for the dual gap. It is shown that the algorithm has O(√nL) iteration complexity which is the best result for convex quadratic programming so far.
LIU Yong; BAI Yan-qin
2009-01-01
A polynomial interior-point algorithm is presented for monotone linear complementarity problem (MLCP) based on:a class of kernel functions with the general barrier term, which are called general kernel functions. Under the mild conditions for the barrier term, the complexity bound of algorithm in terms of such kernel function and its derivatives is obtained. The approach is actually an extension of the existing work which only used the specific kernel functions for the MLCP.
Polynomial-time interior-point algorithm based on a local self-concordant finite barrier function
JIN Zheng-jing; BAI Yan-qin
2009-01-01
The choice of self-concordant functions is the key to efficient algorithms for linear and quadratic convex optimizations,which provide a method with polynomial-time iterations to solve linear and quadratic convex optimization problems.The parameters of a self-concordant barrier function can be used to compute the complexity bound of the proposed algorithm.In this paper,it is proved that the finite barrier function is a local self-concordant barrier function.By deriving the local values of parameters of this barrier function,the desired complexity bound of an interior-point algorithm based on this local serf-concordant function for linear optimization problem is obtained.The bound matches the best known bound for smallupdate methods.
Long step homogeneous interior point algorithm for the p* nonlinear complementarity problems
Lešaja Goran
2002-01-01
Full Text Available A P*-Nonlinear Complementarity Problem as a generalization of the P*-Linear Complementarity Problem is considered. We show that the long-step version of the homogeneous self-dual interior-point algorithm could be used to solve such a problem. The algorithm achieves linear global convergence and quadratic local convergence under the following assumptions: the function satisfies a modified scaled Lipschitz condition, the problem has a strictly complementary solution, and certain submatrix of the Jacobian is nonsingular on some compact set.
应用多波前法快速求解最优协调电压控制问题%Fast Solution for Optimal Coordinated Voltage Control Using Multifrontal Method
郑文杰; 刘明波
2011-01-01
将长期电压稳定场景下的协调电压控制问题用带有微分-代数方程约束的最优控制模型来描述,借助Radau排列技术将这个动态优化问题转化为大型非线性规划模型,并采用非线性原-对偶内点法求解.重点探讨如何应用多波前方法结合近似最小度排序提高求解稀疏线性修正方程的效率.以IEEE 17机162节点系统和新英格兰10机39节点系统作为算例,通过与近似最小度法和反向Cuthill-McKee法排序下三角分解结果进行对比,证实了所述方法在计算速度上的优越性.%A differential algebraic equation optimization model is used to describe the optimal coordinated voltage control problem in the long-term voltage stability scenario. This dynamic optimization problem can be converted into a large-scale nonlinear programming model using Radau collocation method. The nonlinear primal-dual interior-point method is then applied to solve this problem. This paper focuses on application of the multifrontal method to enhance the efficiency of solving sparse linear correction equations by referring to approximate minimum degree permutation. The IEEE 17-generator 162-bus test system and New England 10-generator 39-bus system are used to verify the effectiveness of the method proposed for comparison with the triangular decomposition using other permutation methods such as approximate minimum degree and reversed Cuthill-McKee.
Nakata, M.; Muramatsu, M.; Waki, H.
2008-01-01
We observe that in a simple one-dimensional polynomial optimization problem (POP), the `optimal' values of semidefinite programming (SDP) relaxation problems reported by the standard SDP solvers converge to the optimal value of the POP, while the true optimal values of SDP relaxation problems are st
Generating human-like movements on an anthropomorphic robot using an interior point method
Costa e Silva, E.; Araújo, J. P.; Machado, D.; Costa, M. F.; Erlhagen, W.; Bicho, E.
2013-10-01
In previous work we have presented a model for generating human-like arm and hand movements on an anthropomorphic robot involved in human-robot collaboration tasks. This model was inspired by the Posture-Based Motion-Planning Model of human movements. Numerical results and simulations for reach-to-grasp movements with two different grip types have been presented previously. In this paper we extend our model in order to address the generation of more complex movement sequences which are challenged by scenarios cluttered with obstacles. The numerical results were obtained using the IPOPT solver, which was integrated in our MATLAB simulator of an anthropomorphic robot.
A numerical implementation of an interior point method for semidefinite programming
Benterki Djamel
2003-01-01
Full Text Available This paper is concerned with an algorithm proposed by Alizadeh for linear semidefinite programming. The proof of convergence given by Alizadeh relies on a wrong inequality, we correct the proof. At each step, the algorithm uses a line search. To be efficient, such a line search needs the value of the derivative, we provide this value. Finally, a few numerical examples are treated.
Debin Fang; Qian Yu
2011-01-01
This paper proposes an improved predictor-corrector interior-point algorithm for the linear complementarity problem (LCP) based on the Mizuno-Todd-Ye algorithm. The modified corrector steps in our algorithm cannot only draw the iteration point back to a narrower neighborhood of the center path but also reduce the duality gap. It implies that the improved algorithm can converge faster than the MTY algorithm. The iteration complexity of the improved algorithm is proved to obtain √ ( ) whi...
Debin Fang
2011-01-01
Full Text Available This paper proposes an improved predictor-corrector interior-point algorithm for the linear complementarity problem (LCP based on the Mizuno-Todd-Ye algorithm. The modified corrector steps in our algorithm cannot only draw the iteration point back to a narrower neighborhood of the center path but also reduce the duality gap. It implies that the improved algorithm can converge faster than the MTY algorithm. The iteration complexity of the improved algorithm is proved to obtain √( which is similar to the classical Mizuno-Todd-Ye algorithm. Finally, the numerical experiments show that our algorithm improved the performance of the classical MTY algorithm.
Dollerup, Niels; Jepsen, Michael S.; Damkilde, Lars
2013-01-01
of the precalculation step, which utilizes the principals of the well-known frontal method. The succeeding optimization algorithm is also significantly optimized, by applying a parallel implementation, which eliminates the exponential growth in computational time relative to the element numbers....
孙全才; 程浩忠; 张健; 王琦; 宋越; 刘明松; 杨堤; 李诗旸
2015-01-01
Dynamic reactive power reserve of power system is vital to improve transient voltage security. An novel definition of reactive power reserve considering transient voltage security in transient procession was proposed. Correction coefficient to evaluate reactive power reserve's contribution to transient voltage security was given. Corrected reactive power reserve was computed through trace sensitivity method. Then an optimization model to enhance transient voltage security was built. It was solved by primal dual interior point method. Testing on IEEE 39-node system,it is indicated that three weight coefficients proposed are reasonable and effective. The evaluation method can give consideration both supporting capacity of one bus to the other and demand of reactive power reserve according to severity of faults. The system's transient voltage security is enhanced by the way of optimization of system's dynamic reactive power reserve. Hence, the method proposed can be used to prevent the happening of transient voltage collapse during system's fault.%电力系统动态无功储备对提高系统暂态电压安全水平具有重要作用,因此提出一种在系统暂态过程中考虑暂态电压安全的无功备用概念,并给出其对暂态电压安全贡献的评价方法及相应的修正系数.通过轨迹灵敏度方法实现对修正后的无功源动态无功备用的计算,建立提高系统暂态电压安全水平的无功备用优化模型,利用原对偶内点法进行求解.IEEE 39节点算例结果表明,所提3种权重系数合理、有效,通过该评价方式可以充分考虑到无功备用点对点的支撑能力以及故障严重性对无功备用的要求程度,通过系统动态无功备用的优化可提高系统的整体暂态电压安全水平,因此所提方法能够有效地预防系统故障时暂态电压安全问题的发生.
Interior point algorithm-based power flow optimisation of a combined AC and DC multi-terminal grid
Farhan Beg
2015-01-01
Full Text Available The high cost of power electronic equipment, lower reliability and poor power handling capacity of the semiconductor devices had stalled the deployment of systems based on DC (multi-terminal direct current system (MTDC networks. The introduction of voltage source converters (VSCs for transmission has renewed the interest in the development of large interconnected grids based on both alternate current (AC and DC transmission networks. Such a grid platform also realises the added advantage of integrating the renewable energy sources into the grid. Thus a grid based on DC MTDC network is a possible solution to improve energy security and check the increasing supply demand gap. An optimal power solution for combined AC and DC grids obtained by the solution of the interior point algorithm is proposed in this study. Multi-terminal HVDC grids lie at the heart of various suggested transmission capacity increases. A significant difference is observed when MTDC grids are solved for power flows in place of conventional AC grids. This study deals with the power flow problem of a combined MTDC and an AC grid. The AC side is modelled with the full power flow equations and the VSCs are modelled using a connecting line, two generators and an AC node. The VSC and the DC losses are also considered. The optimisation focuses on several different goals. Three different scenarios are presented in an arbitrary grid network with ten AC nodes and five converter stations.
陶向红; 卜广全; 王虹富; 鲍威; 郭瑞鹏
2014-01-01
Manually altering the output flow and load by experienced operators is the most widely used way when the power system power flow calculation has no feasible solution.To find out the critical causes while restoring the power flow solvability,this paper proposes a practical power flow restoration optimization model,with the absolute value of bus inj ection deviation as the optimizing obj ective and the problem solved by the primal-dual interior point method.The proposed method is able to find out the improper bus inj ections and optimize the system to obtain solvable power flow calculations.Simulations on Institute of Electrical and Electronics Engineers (IEEE) standard systems and practical bulk power systems have proved the effectiveness and correctness of the proposed method.The calculation scale capability and calculating efficiency is qualified for practical applications. This work is supported by National High Technology Research and Development Program of China (863 Program) (No.2011AA05Al18).%电力系统基本潮流无可行解时，通常只能根据经验以人工对可调的负荷出力进行反复调试才能获得一个较接近初始状态的新可行解。为了在恢复潮流可行解的同时，找到原运行方式中导致无解的症结，以节点注入偏差量绝对值最小为目标，提出了一种新的潮流恢复实用模型，并采用原—对偶内点法求解。对IEEE标准系统及实际超大电网系统的仿真表明该模型有效，优化结果可以较好地辨识出导致原运行方式无潮流可行解的节点出力和负荷，计算效率已达到实际应用水平。
A full-Newton step feasible interior-point algorithm for P∗(κ-LCP based on a new search direction
Behrouz Kheirfam
2016-12-01
Full Text Available In this paper, we present a full-Newton step feasible interior-point algorithm for a P∗(κ linear complementarity problem based on a new search direction. We apply a vector-valued function generated by a univariate function on nonlinear equations of the system which defines the central path. Furthermore, we derive the iteration bound for the algorithm, which coincides with the best-known iteration bound for these types of algorithms. Numerical results show that the proposed algorithm is competitive and reliable.
On-board Model Predictive Control of a Quadrotor Helicopter: Design, Implementation, and Experiments
2012-12-13
when the controller recovered from large disturbances; typically the path back to the origin would not be along a straight line but rather one or the... back to x1 = −1 m after a delay of 3.5 s. We performed this test with both linear MPC (using only the nominal model) and with LBMPC. Fig. Fig.4.3 shows...The proposed primal-dual infeasible start interior point method (PD IIPM) based on Mehrotra’s predictor- corrector scheme (Mehrotra, 1992) was
Linear programming mathematics, theory and algorithms
1996-01-01
Linear Programming provides an in-depth look at simplex based as well as the more recent interior point techniques for solving linear programming problems. Starting with a review of the mathematical underpinnings of these approaches, the text provides details of the primal and dual simplex methods with the primal-dual, composite, and steepest edge simplex algorithms. This then is followed by a discussion of interior point techniques, including projective and affine potential reduction, primal and dual affine scaling, and path following algorithms. Also covered is the theory and solution of the linear complementarity problem using both the complementary pivot algorithm and interior point routines. A feature of the book is its early and extensive development and use of duality theory. Audience: The book is written for students in the areas of mathematics, economics, engineering and management science, and professionals who need a sound foundation in the important and dynamic discipline of linear programming.
An Object Oriented Approach to Semidefinite Programming
Ge, Yuzhen; Watson, Layne; Collins, Emmanuel
1998-01-01
An object-oriented design and implementation of a primal-dual algorithm for solving the semidefinite programming problem is presented. The advantages of applying the object-oriented methodology to numerical computations, in particular to an interior point algorithm for semidefinite programming, or for solving other types of linear matrix inequalities are discussed. One object-oriented design of the primal-dual algorithm and its implementation using C++ is presented. The performance of the ...
Dynamic mortar finite element method for modeling of shear rupture on frictional rough surfaces
Tal, Yuval; Hager, Bradford H.
2017-09-01
This paper presents a mortar-based finite element formulation for modeling the dynamics of shear rupture on rough interfaces governed by slip-weakening and rate and state (RS) friction laws, focusing on the dynamics of earthquakes. The method utilizes the dual Lagrange multipliers and the primal-dual active set strategy concepts, together with a consistent discretization and linearization of the contact forces and constraints, and the friction laws to obtain a semi-smooth Newton method. The discretization of the RS friction law involves a procedure to condense out the state variables, thus eliminating the addition of another set of unknowns into the system. Several numerical examples of shear rupture on frictional rough interfaces demonstrate the efficiency of the method and examine the effects of the different time discretization schemes on the convergence, energy conservation, and the time evolution of shear traction and slip rate.
Neighborhood-following algorithms for linear programming
AI Wenbao
2004-01-01
In this paper, we present neighborhood-following algorithms for linear programming. When the neighborhood is a wide neighborhood, our algorithms are wide neighborhood primal-dual interior point algorithms. If the neighborhood degenerates into the central path, our algorithms also degenerate into path-following algorithms. We prove that our algorithms maintain the O(√nL)-iteration complexity still, while the classical wide neighborhood primal-dual interior point algorithms have only the O(nL)-iteration complexity. We also proved that the algorithms are quadratic convergence if the optimal vertex is nondegenerate. Finally, we show some computational results of our algorithms.
Barbu, Ioana; Herzet, Cédric
2016-10-01
We adapt and import into the TomoPIV scenery a fast algorithm for solving the volume reconstruction problem. Our approach is based on the reformulation of the volume reconstruction task as a constrained optimization problem and the resort to the ‘alternating directions method of multipliers’ (ADMM). The inherent primal-dual algorithm is summarized in this article to solve the optimization problem related to the TomoPIV. In particular, the general formulation of the volume reconstruction problem considered in this paper allows one to: (i) take explicitly into account the level of the noise affecting the data; (ii) account for both the nonnegativity and the sparsity of the solution. Experiments on a numerical TomoPIV benchmark show that the proposed framework is a serious contender for the state-of-the-art.
L. M. Kimball
2002-01-01
Full Text Available This paper presents an interior point algorithm to solve the multiperiod hydrothermal economic dispatch (HTED. The multiperiod HTED is a large scale nonlinear programming problem. Various optimization methods have been applied to the multiperiod HTED, but most neglect important network characteristics or require decomposition into thermal and hydro subproblems. The algorithm described here exploits the special bordered block diagonal structure and sparsity of the Newton system for the first order necessary conditions to result in a fast efficient algorithm that can account for all network aspects. Applying this new algorithm challenges a conventional method for the use of available hydro resources known as the peak shaving heuristic.
Improving the primal-dual algorithm for the transportation problem in the plane
Kaijser, Thomas
2009-01-01
The transportation problem in the plane - how to move a set of objects from one set of points to another set of points in the cheapest way - is a very old problem going back several hundreds of years. In recent years the solution of the problem has found applications in the analysis of digital images when searching for similarities and discrepancies between images. The main drawback, however, is the long computation time for finding the solution. In this paper we present some new results by which the time for solving the transportation problem in the plane can be reduced substantially. As cost-function we choose a distance-function between points in the plane. We consider both the case when the distance-function is equal to the ordinary Euclidean distance, as well as the case when the distance-function is equal to the square of the Euclidean distance. This latter distance-function has the advantage that it is integer-valued if the coordinates of the points in the plane are integers.
Modelling and analysing 3D buildings with a primal/dual data structure
Boguslawski, P.; Gold, C.; Ledoux, H.
2011-01-01
While CityGML permits us to represent 3D city models, its use for applications where spatial analysis and/or real-time modifications are required is limited since at this moment the possibility to store topological relationships between the elements is rather limited and often not exploited. We pres
Modelling and analysing 3D buildings with a primal/dual data structure
Boguslawski, P.; Gold, C.; Ledoux, H.
2011-01-01
While CityGML permits us to represent 3D city models, its use for applications where spatial analysis and/or real-time modifications are required is limited since at this moment the possibility to store topological relationships between the elements is rather limited and often not exploited. We
Fuzzy optimization of primal-dual pair using piecewise linear membership functions
Pandey D.
2012-01-01
Full Text Available Present paper improves the model of Bector and Chandra [Fuzzy Sets and Systems, 125 (2002 317-325] on duality in fuzzy linear programming by using non-linear membership functions. Numerical problem discussed by these authors has also been worked out through our non-linear model to demonstrate improved optimality of the results.
Barbosa, Diego R.; Silva, Alessandro L. da; Luciano, Edson Jose Rezende; Nepomuceno, Leonardo [Universidade Estadual Paulista (UNESP), Bauru, SP (Brazil). Dept. de Engenharia Eletrica], Emails: diego_eng.eletricista@hotmail.com, alessandrolopessilva@uol.com.br, edson.joserl@uol.com.br, leo@feb.unesp.br
2009-07-01
Problems of DC Optimal Power Flow (OPF) have been solved by various conventional optimization methods. When the modeling of DC OPF involves discontinuous functions or not differentiable, the use of solution methods based on conventional optimization is often not possible because of the difficulty in calculating the gradient vectors at points of discontinuity/non-differentiability of these functions. This paper proposes a method for solving the DC OPF based on Genetic Algorithms (GA) with real coding. The proposed GA has specific genetic operators to improve the quality and viability of the solution. The results are analyzed for an IEEE test system, and its solutions are compared, when possible, with those obtained by a method of interior point primal-dual logarithmic barrier. The results highlight the robustness of the method and feasibility of obtaining the solution to real systems.
Coordinated Voltage Control of Active Distribution Network
Xie Jiang
2016-01-01
Full Text Available This paper presents a centralized coordinated voltage control method for active distribution network to solve off-limit problem of voltage after incorporation of distributed generation (DG. The proposed method consists of two parts, it coordinated primal-dual interior point method-based voltage regulation schemes of DG reactive powers and capacitors with centralized on-load tap changer (OLTC controlling method which utilizes system’s maximum and minimum voltages, to improve the qualified rate of voltage and reduce the operation numbers of OLTC. The proposed coordination has considered the cost of capacitors. The method is tested using a radial edited IEEE-33 nodes distribution network which is modelled using MATLAB.
Linear programming foundations and extensions
Vanderbei, Robert J
2001-01-01
Linear Programming: Foundations and Extensions is an introduction to the field of optimization. The book emphasizes constrained optimization, beginning with a substantial treatment of linear programming, and proceeding to convex analysis, network flows, integer programming, quadratic programming, and convex optimization. The book is carefully written. Specific examples and concrete algorithms precede more abstract topics. Topics are clearly developed with a large number of numerical examples worked out in detail. Moreover, Linear Programming: Foundations and Extensions underscores the purpose of optimization: to solve practical problems on a computer. Accordingly, the book is coordinated with free efficient C programs that implement the major algorithms studied: -The two-phase simplex method; -The primal-dual simplex method; -The path-following interior-point method; -The homogeneous self-dual methods. In addition, there are online JAVA applets that illustrate various pivot rules and variants of the simplex m...
Hopping trajectory optimization for surface exploration on small bodies
Liu, Yanjie; Zhu, Shengying; Cui, Pingyuan; Yu, Zhengshi; Zong, Hua
2017-07-01
Surface exploration is an important way to improve the understanding of small bodies. Considering the irregular and weak gravity field near a small body, the movement of the surface explorer is generally achieved by hopping. In this paper, a guidance algorithm method based on convex optimization approach for pinpoint hopping movement on a small body is developed in order to improve the stability and accuracy of surface exploration. We formulate a fuel-optimal control problem for the single pinpoint hopping and convert it into a second-order cone programming (SOCP) problem which can be solved effectively by primal-dual-interior points method. A multi-hopping scenario is also proposed for the long-distance transfer. To certificate the performance of the proposed guidance algorithm, a full set of simulations are conducted and the effectiveness are analyzed.
X. Zhao
2012-01-01
Full Text Available A combined interior point homotopy continuation method is proposed for solving general multiobjective programming problem. We prove the existence and convergence of a smooth homotopy path from almost any interior initial interior point to a solution of the KKT system under some basic assumptions.
Zhou, W.; Qiu, G. Y.; Oodo, S. O.; He, H.
2013-03-01
An increasing interest in wind energy and the advance of related technologies have increased the connection of wind power generation into electrical grids. This paper proposes an optimization model for determining the maximum capacity of wind farms in a power system. In this model, generator power output limits, voltage limits and thermal limits of branches in the grid system were considered in order to limit the steady-state security influence of wind generators on the power system. The optimization model was solved by a nonlinear primal-dual interior-point method. An IEEE-30 bus system with two wind farms was tested through simulation studies, plus an analysis conducted to verify the effectiveness of the proposed model. The results indicated that the model is efficient and reasonable.
A multiscale two-point flux-approximation method
Møyner, Olav; Lie, Knut-Andreas
2014-10-01
A large number of multiscale finite-volume methods have been developed over the past decade to compute conservative approximations to multiphase flow problems in heterogeneous porous media. In particular, several iterative and algebraic multiscale frameworks that seek to reduce the fine-scale residual towards machine precision have been presented. Common for all such methods is that they rely on a compatible primal-dual coarse partition, which makes it challenging to extend them to stratigraphic and unstructured grids. Herein, we propose a general idea for how one can formulate multiscale finite-volume methods using only a primal coarse partition. To this end, we use two key ingredients that are computed numerically: (i) elementary functions that correspond to flow solutions used in transmissibility upscaling, and (ii) partition-of-unity functions used to combine elementary functions into basis functions. We exemplify the idea by deriving a multiscale two-point flux-approximation (MsTPFA) method, which is robust with regards to strong heterogeneities in the permeability field and can easily handle general grids with unstructured fine- and coarse-scale connections. The method can easily be adapted to arbitrary levels of coarsening, and can be used both as a standalone solver and as a preconditioner. Several numerical experiments are presented to demonstrate that the MsTPFA method can be used to solve elliptic pressure problems on a wide variety of geological models in a robust and efficient manner.
A primal–dual hybrid gradient method for nonlinear operators with applications to MRI
Valkonen, Tuomo
2014-05-01
We study the solution of minimax problems min xmax yG(x) + K(x), y - F*(y) in finite-dimensional Hilbert spaces. The functionals G and F* we assume to be convex, but the operator K we allow to be nonlinear. We formulate a natural extension of the modified primal-dual hybrid gradient method, originally for linear K, due to Chambolle and Pock. We prove the local convergence of the method, provided various technical conditions are satisfied. These include in particular the Aubin property of the inverse of a monotone operator at the solution. Of particular interest to us is the case arising from Tikhonov type regularization of inverse problems with nonlinear forward operators. Mainly we are interested in total variation and second-order total generalized variation priors. For such problems, we show that our general local convergence result holds when the noise level of the data f is low, and the regularization parameter α is correspondingly small. We verify the numerical performance of the method by applying it to problems from magnetic resonance imaging (MRI) in chemical engineering and medicine. The specific applications are in diffusion tensor imaging and MR velocity imaging. These numerical studies show very promising performance. © 2014 IOP Publishing Ltd.
王成山; 张义
2003-01-01
对于目标为网损费用和无功设备投资费用最小的无功优化规划问题,Bender's分解技术是一种有效的解决方法.原-对偶仿射尺度法作为一种被证明具有多项式时间复杂性的方法,已经被用于无功优化的计算中.本文结合Bender's分解技术和原-对偶仿射尺度法,解决了城市高中压配电网的长期无功优化规划问题.通过实际电力系统的计算结果表明,此算法的迭代收敛次数稳定,优化结果的经济效益明显,适合于大规模电力系统的无功优化规划计算.
Orecchia, Lorenzo
2010-01-01
In this paper, we consider the following graph partitioning problem: The input is an undirected graph $G=(V,E),$ a balance parameter $b \\in (0,1/2]$ and a target conductance value $\\gamma \\in (0,1).$ The output is a cut which, if non-empty, is of conductance at most $O(f),$ for some function $f(G, \\gamma),$ and which is either balanced or well correlated with all cuts of conductance at most $\\gamma.$ Spielman and Teng gave an $\\tilde{O}(|E|/\\gamma^{2})$-time algorithm for $f= \\sqrt{\\gamma \\log^{3}|V|}$ and used it to decompose graphs into a collection of near-expanders. We present a new spectral algorithm for this problem which runs in time $\\tilde{O}(|E|/\\gamma)$ for $f=\\sqrt{\\gamma}.$ Our result yields the first nearly-linear time algorithm for the classic Balanced Separator problem that achieves the asymptotically optimal approximation guarantee for spectral methods. Our method has the advantage of being conceptually simple and relies on a primal-dual semidefinite-programming SDP approach. We first conside...
A HYBRID METHOD FOR LINEAR PROGRAMMING
XIU Naihua; WU Fang
1999-01-01
In this paper, a hybrid method for linear programming is established.Its search direction is defined as a combination of two directions insimplex method and affine-scaling interior point method.The method is proven to have some promising convergence properties.The relation among the new method, the simplex method and the affine-scalinginteriorpoint method is discussed.
Fast alternating projection methods for constrained tomographic reconstruction.
Liu, Li; Han, Yongxin; Jin, Mingwu
2017-01-01
The alternating projection algorithms are easy to implement and effective for large-scale complex optimization problems, such as constrained reconstruction of X-ray computed tomography (CT). A typical method is to use projection onto convex sets (POCS) for data fidelity, nonnegative constraints combined with total variation (TV) minimization (so called TV-POCS) for sparse-view CT reconstruction. However, this type of method relies on empirically selected parameters for satisfactory reconstruction and is generally slow and lack of convergence analysis. In this work, we use a convex feasibility set approach to address the problems associated with TV-POCS and propose a framework using full sequential alternating projections or POCS (FS-POCS) to find the solution in the intersection of convex constraints of bounded TV function, bounded data fidelity error and non-negativity. The rationale behind FS-POCS is that the mathematically optimal solution of the constrained objective function may not be the physically optimal solution. The breakdown of constrained reconstruction into an intersection of several feasible sets can lead to faster convergence and better quantification of reconstruction parameters in a physical meaningful way than that in an empirical way of trial-and-error. In addition, for large-scale optimization problems, first order methods are usually used. Not only is the condition for convergence of gradient-based methods derived, but also a primal-dual hybrid gradient (PDHG) method is used for fast convergence of bounded TV. The newly proposed FS-POCS is evaluated and compared with TV-POCS and another convex feasibility projection method (CPTV) using both digital phantom and pseudo-real CT data to show its superior performance on reconstruction speed, image quality and quantification.
王浚岭
2005-01-01
In this paper a high-order feasible interior point algorithm for a class of nonmonotonic (P-matrix) linear complementary problem based on large neighborhoods of central path is presented and its iteration complexity is discussed.These algorithms are implicitly associated with a large neighborhood whose size may depend on the dimension of the problems. The complexity of these algorithms bound depends on the size of the neighborhood. It is well known that the complexity of large-step algorithms is greater than that of short- step ones. By using high-order power series (hence the name high-order algorithms), the iteration complexity can be reduced. We show that the upper bound of complexity for our high-order algorithms is equal to that for short-step algorithms.
Replica analysis for the duality of the portfolio optimization problem
Shinzato, Takashi
2016-11-01
In the present paper, the primal-dual problem consisting of the investment risk minimization problem and the expected return maximization problem in the mean-variance model is discussed using replica analysis. As a natural extension of the investment risk minimization problem under only a budget constraint that we analyzed in a previous study, we herein consider a primal-dual problem in which the investment risk minimization problem with budget and expected return constraints is regarded as the primal problem, and the expected return maximization problem with budget and investment risk constraints is regarded as the dual problem. With respect to these optimal problems, we analyze a quenched disordered system involving both of these optimization problems using the approach developed in statistical mechanical informatics and confirm that both optimal portfolios can possess the primal-dual structure. Finally, the results of numerical simulations are shown to validate the effectiveness of the proposed method.
Sparse deconvolution for the large-scale ill-posed inverse problem of impact force reconstruction
Qiao, Baijie; Zhang, Xingwu; Gao, Jiawei; Liu, Ruonan; Chen, Xuefeng
2017-01-01
Most previous regularization methods for solving the inverse problem of force reconstruction are to minimize the l2-norm of the desired force. However, these traditional regularization methods such as Tikhonov regularization and truncated singular value decomposition, commonly fail to solve the large-scale ill-posed inverse problem in moderate computational cost. In this paper, taking into account the sparse characteristic of impact force, the idea of sparse deconvolution is first introduced to the field of impact force reconstruction and a general sparse deconvolution model of impact force is constructed. Second, a novel impact force reconstruction method based on the primal-dual interior point method (PDIPM) is proposed to solve such a large-scale sparse deconvolution model, where minimizing the l2-norm is replaced by minimizing the l1-norm. Meanwhile, the preconditioned conjugate gradient algorithm is used to compute the search direction of PDIPM with high computational efficiency. Finally, two experiments including the small-scale or medium-scale single impact force reconstruction and the relatively large-scale consecutive impact force reconstruction are conducted on a composite wind turbine blade and a shell structure to illustrate the advantage of PDIPM. Compared with Tikhonov regularization, PDIPM is more efficient, accurate and robust whether in the single impact force reconstruction or in the consecutive impact force reconstruction.
Stress-based upper-bound method and convex optimization: case of the Gurson material
Pastor, Franck; Trillat, Malorie; Pastor, Joseph; Loute, Etienne
2006-04-01
A nonlinear interior point method associated with the kinematic theorem of limit analysis is proposed. Associating these two tools enables one to determine an upper bound of the limit loading of a Gurson material structure from the knowledge of the sole yield criterion. We present the main features of the interior point algorithm and an original method providing a rigorous kinematic bound from a stress formulation of the problem. This method is tested by solving in plane strain the problem of a Gurson infinite bar compressed between rough rigid plates. To cite this article: F. Pastor et al., C. R. Mecanique 334 (2006).
Word, Daniel P; Cummings, Derek A T; Burke, Donald S; Iamsirithaworn, Sopon; Laird, Carl D
2012-08-07
Mathematical models can enhance our understanding of childhood infectious disease dynamics, but these models depend on appropriate parameter values that are often unknown and must be estimated from disease case data. In this paper, we develop a framework for efficient estimation of childhood infectious disease models with seasonal transmission parameters using continuous differential equations containing model and measurement noise. The problem is formulated using the simultaneous approach where all state variables are discretized, and the discretized differential equations are included as constraints, giving a large-scale algebraic nonlinear programming problem that is solved using a nonlinear primal-dual interior-point solver. The technique is demonstrated using measles case data from three different locations having different school holiday schedules, and our estimates of the seasonality of the transmission parameter show strong correlation to school term holidays. Our approach gives dramatic efficiency gains, showing a 40-400-fold reduction in solution time over other published methods. While our approach has an increased susceptibility to bias over techniques that integrate over the entire unknown state-space, a detailed simulation study shows no evidence of bias. Furthermore, the computational efficiency of our approach allows for investigation of a large model space compared with more computationally intensive approaches.
1988-12-01
Researchers have suggested other solution strategies, using ideas from nonlinear progamming for solving this general separable convex cost flow problems. Some...plane methods and branch and bound procedures of integer programming, primal-dual methods of linear and nonlinear programming, and polyhedral methods...Combinatorial Optimization: Networks and Matroids), Bazaraa and Jarvis [1978] (Linear Programming and Network Flows), Minieka [1978] (Optimization Algorithms for
Pawel Boguslawski
2016-02-01
Full Text Available There is an increasing need for building models that permit interior navigation, e.g., for escape route analysis. This paper presents a non-manifold Computer-Aided Design (CAD data structure, the dual half-edge based on the Poincaré duality that expresses both the geometric representations of individual rooms and their topological relationships. Volumes and faces are expressed as vertices and edges respectively in the dual space, permitting a model just based on the storage of primal and dual vertices and edges. Attributes may be attached to all of these entities permitting, for example, shortest path queries between specified rooms, or to the exterior. Storage costs are shown to be comparable to other non-manifold models, and construction with local Euler-type operators is demonstrated with two large university buildings. This is intended to enhance current developments in 3D Geographic Information Systems for interior and exterior city modelling.
Variational approach for restoring blurred images with cauchy noise
Sciacchitano, Federica; Dong, Yiqiu; Zeng, Tieyong
2015-01-01
model, we add a quadratic penalty term, which guarantees the uniqueness of the solution. Due to the convexity of our model, the primal dual algorithm is employed to solve the minimization problem. Experimental results show the effectiveness of the proposed method for simultaneously deblurring...... and denoising images corrupted by Cauchy noise. Comparison with other existing and well-known methods is provided as well....
Reactive power and voltage control based on general quantum genetic algorithms
Vlachogiannis, Ioannis (John); Østergaard, Jacob
2009-01-01
This paper presents an improved evolutionary algorithm based on quantum computing for optima l steady-state performance of power systems. However, the proposed general quantum genetic algorithm (GQ-GA) can be applied in various combinatorial optimization problems. In this study the GQ-GA determines...... techniques such as enhanced GA, multi-objective evolutionary algorithm and particle swarm optimization algorithms, as well as the classical primal-dual interior-point optimal power flow algorithm. The comparison demonstrates the ability of the GQ-GA in reaching more optimal solutions....
A simple dual ascent algorithm for the multilevel facility location problem
Bumb, Adriana; Kern, Walter; Goemans, Michel; Jansen, Klaus; Rolim, José D.P.; Trevisan, Luca
2001-01-01
We present a simple dual ascent method for the multilevel facility location problem which finds a solution within 6 times the optimum for the uncapacitated case and within 12 times the optimum for the capacitated one. The algorithm is deterministic and based on the primal-dual technique.
Causal Video Object Segmentation From Persistence of Occlusions
2015-05-01
spond to “objects” is elusive absent an explicit definition of objects that has a measurable correlate in the image. Gestalt principles [33] provide...by Gestalt principles to arrive at a con- vex optimization scheme that can be efficiently solved with primal-dual methods. To compare with existing
Numerical Methods for Solution of the Extended Linear Quadratic Control Problem
Jørgensen, John Bagterp; Frison, Gianluca; Gade-Nielsen, Nicolai Fog
2012-01-01
to the Karush-Kuhn-Tucker system that constitute the majority of computational work in constrained nonlinear and linear model predictive control problems solved by efficient MPC-tailored interior-point and active-set algorithms. We state various methods of solving the extended linear quadratic control problem...
A Continuation Method for Solving Fixed Point Problems in Unbounded Convex Sets
SU MENG-LONG; LU XIAN-RUI; MA YONG
2009-01-01
In this paper, an unbounded condition is presented, under which we are able to utilize the interior point homotopy method to solve the Brouwer fixed point problem on unbounded sets. Two numerical examples in R3 are presented to illustrate the results in this paper.
Mathematical programming methods for large-scale topology optimization problems
Rojas Labanda, Susana
, and at the same time, reduce the number of function evaluations. Nonlinear optimization methods, such as sequential quadratic programming and interior point solvers, have almost not been embraced by the topology optimization community. Thus, this work is focused on the introduction of this kind of second......This thesis investigates new optimization methods for structural topology optimization problems. The aim of topology optimization is finding the optimal design of a structure. The physical problem is modelled as a nonlinear optimization problem. This powerful tool was initially developed...... for the classical minimum compliance problem. Two of the state-of-the-art optimization algorithms are investigated and implemented for this structural topology optimization problem. A Sequential Quadratic Programming (TopSQP) and an interior point method (TopIP) are developed exploiting the specific mathematical...
Qin Ni; Ch. Zillober; K. Schittkowski
2005-01-01
In this paper, we describe a method to solve large-scale structural optimization problems by sequential convex programming (SCP). A predictor-corrector interior point method is applied to solve the strictly convex subproblems. The SCP algorithm and the topology optimization approach are introduced. Especially, different strategies to solve certain linear systems of equations are analyzed. Numerical results are presented to show the efficiency of the proposed method for solving topology optimization problems and to compare different variants.
SU-F-18C-13: Low-Dose X-Ray CT Reconstruction Using a Hybrid First-Order Method
Liu, L; Lin, W [Tianjin University, Tianjin (China); Jin, M [University of Texas at Arlington, Arlington, TX (United States)
2014-06-15
Purpose: To develop a novel reconstruction method for X-ray CT that can lead to accurate reconstruction at significantly reduced dose levels combining low X-ray incident intensity and few views of projection data. Methods: The noise nature of the projection data at low X-ray incident intensity was modeled and accounted by the weighted least-squares (WLS) criterion. The total variation (TV) penalty was used to mitigate artifacts caused by few views of data. The first order primal-dual (FOPD) algorithm was used to minimize TV in image domain, which avoided the difficulty of the non-smooth objective function. The TV penalized WLS reconstruction was achieved by alternated FOPD TV minimization and projection onto convex sets (POCS) for data fidelity constraints. The proposed FOPD-POCS method was evaluated using the FORBILD jaw phantom and the real cadaver head CT data. Results: The quantitative measures, root mean square error (RMSE) and contrast-to-noise ratio (CNR), demonstrate the superior denoising capability of WLS over LS-based TV iterative reconstruction. The improvement of RMSE (WLS vs. LS) is 15%∼21% and that of CNR is 17%∼72% when the incident counts per ray are ranged from 1×10{sup 5} to 1×10{sup 3}. In addition, the TV regularization can accurately reconstruct images from about 50 views of the jaw phantom. The FOPD-POCS reconstruction reveals more structural details and suffers fewer artifacts in both the phantom and real head images. The FOPD-POCS method also shows fast convergence at low X-ray incident intensity. Conclusion: The new hybrid FOPD-POCS method, based on TV penalized WLS, yields excellent image quality when the incident X-ray intensity is low and the projection views are limited. The reconstruction is computationally efficient since the FOPD minimization of TV is applied only in the image domain. The characteristics of FOPD-POCS can be exploited to significantly reduce radiation dose of X-ray CT without compromising accuracy for diagnosis
苗轶群; 江全元; 曹一家
2012-01-01
Because of the power output indeterminacy of distributed generations,such as wind power,solar power and so on,a fuzzy OPF(Optimal Power Flow) model combining the trapezoidal fuzzy number with the OPF is established, which, based on the fuzzy mathematics theory, expresses the nondeterministic power output as a fuzzy number. According to the comparison rules of fuzzy number,the weighted shifting method is applied to convert the fuzzy objective function and constraints to deterministic ones. The primal-dual interior point method is used to solve the model. Simulative result of a 24-bus urban power grid indicates the average optimal value is obtained when some power outputs are nondeterministic.%考虑多种不确定因素的随机性,在预测值与概率分布统计规律的基础上,应用区间系数规划(ICP)与机会约束规划(CCP)建立了考虑电动汽车与可再生能源的含换电站的微网随机调度模型,进一步将其转化为确定性混合整数线性规划(MILP)模型,并利用CPLEX软件求解.算例分析结果表明,根据所提模型得到的开停机方案可以在可再生能源功率、电动汽车充放电功率等实测值偏离预测值时,满足系统功率平衡要求,并以接近于1的概率满足备用需求,比传统确定性模型得到的方案更经济.
廖迎晨; 甘德强; 陈星莺; 余昆
2012-01-01
Because of the power output indeterminacy of distributed generations,such as wind power,solar power and so on,a fuzzy OPF(Optimal Power Flow) model combining the trapezoidal fuzzy number with the OPF is established, which, based on the fuzzy mathematics theory, expresses the nondeterministic power output as a fuzzy number. According to the comparison rules of fuzzy number,the weighted shifting method is applied to convert the fuzzy objective function and constraints to deterministic ones. The primal-dual interior point method is used to solve the model. Simulative result of a 24-bus urban power grid indicates the average optimal value is obtained when some power outputs are nondeterministic.%针对风力发电、太阳能发电等分布式电源出力的不确定性,引入模糊数学理论将不确定性的发电出力用模糊数表示,将梯形模糊数与最优潮流结合建立城市电网模糊最优潮流模型.依据模糊数的比较规则,通过加权位移法将模糊目标函数和模糊约束转化为确定性目标函数与约束,并采用原对偶内点法进行求解.对一24节点城市电网进行仿真分析,结果表明在某些出力不确定情况下所得优化结果是平均最优值.
大规模电网的动态无功优化算法%Algorithm for Dynamic Reactive Power Optimization Problem in Large Power Grid
赖永生; 刘明波; 陈燕梅
2012-01-01
In order to resolve the so-called problem of "curse of dimensionality", this paper analyzed dynamic reactive-power optimization by using nonlinear primal-dual interior-point algorithm which introduced discretization penalty and showed the further exploration of block-matrix decoupling method used in the coefficient matrix of the reduced linear correction equation. Moreover, a realization of exchanging time for space (time-space transformation) by twice computing coefficient matrix of the reduced linear correction equation and its triangular factorization which can reduce the data storage is given. The numerical results on IEEE 118-bus system and two real power supply systems with 14 nodes and 538 nodes show that the proposed algorithm is suitable for u-sing in large-scale power systems and has fast calculation speed.%为解决应用内嵌离散惩罚的非线性原对偶内点法求解离散整数动态无功优化模型时产生的“维数灾”问题,对修正方程用块矩阵解耦的算法做进一步探讨,提出了两次求解修正方程系数矩阵并三角分解从而降低动态无功优化应用于大电网时的数据存储量的新思路,即以时间换取空间(定义为时空转换).在两个实际系统(14节点和538节点系统)和IEEE 118节点系统上的优化计算表明,所提算法既能计算大电网的动态无功优化,又具有较快的计算速度.
李泓泽; 王宝; 郭森; 苏晨博
2013-01-01
为将风电场出力存在偏差时电网公司单位购电成本变化量控制在可接受的范围内,有必要确定其最大变动范围.本文通过构建含风电场的优化调度模型,并借助于原对偶内点算法对其求解,定量识别了风电场出力存在偏差时电网公司单位购电成本变化量及其主要影响因素,进而基于回归分析方法测度了风电场出力偏差幅度的最大变动范围.算例结果验证了该方法的合理性和有效性.%According to the output deviation of wind farm,it is necessary to determine its maximum change range to constrain the change in Grid Company's power purchase unit cost within the acceptable range.This paper quantitatively identifies the change in Grid Company's power purchase unit cost as well as its main influencing factors when wind farm has output deviation by establishing an optimal dispatching model with wind farm considered and applying the primal-dual interior point algorithm to its solving.Subsequently,the maximum change range of wind farm's output deviation is measured on the basis of regression analysis.The results of test example demonstrate the rationality and validity of the proposed method.
Distributive Network Utility Maximization (NUM) over Time-Varying Fading Channels
Chen, Junting; Lau, Vincent K N
2011-01-01
Distributed network utility maximization (NUM) has received an increasing intensity of interest over the past few years. Distributed solutions (e.g., the primal-dual gradient method) have been intensively investigated under fading channels. As such distributed solutions involve iterative updating and explicit message passing, it is unrealistic to assume that the wireless channel remains unchanged during the iterations. Unfortunately, the behavior of those distributed solutions under time-varying channels is in general unknown. In this paper, we shall investigate the convergence behavior and tracking errors of the iterative primal-dual scaled gradient algorithm (PDSGA) with dynamic scaling matrices (DSC) for solving distributive NUM problems under time-varying fading channels. We shall also study a specific application example, namely the multi-commodity flow control and multi-carrier power allocation problem in multi-hop ad hoc networks. Our analysis shows that the PDSGA converges to a limit region rather tha...
Kudo, Hiroyuki; Nemoto, Takuya; Takaki, Keita
2016-01-01
This paper concerns iterative reconstruction for low-dose and few-view CT by minimizing a data-fidelity term regularized with the Total Variation (TV) penalty. We propose a very fast iterative algorithm to solve this problem. The algorithm derivation is outlined as follows. First, the original minimization problem is reformulated into the saddle point (primal-dual) problem by using the Lagrangian duality, to which we apply the first-order primal-dual iterative methods. Second, we precondition the iteration formula using the ramp flter of Filtered Backprojection (FBP) reconstruction algorithm in such a way that the problem solution is not altered. The resulting algorithm resembles the structure of so-called iterative FBP algorithm, and it converges to the exact minimizer of cost function very fast.
Hitting Diamonds and Growing Cacti
Fiorini, Samuel; Joret, Gwenaël; Pietropaoli, Ugo
We consider the following NP-hard problem: in a weighted graph, find a minimum cost set of vertices whose removal leaves a graph in which no two cycles share an edge. We obtain a constant-factor approximation algorithm, based on the primal-dual method. Moreover, we show that the integrality gap of the natural LP relaxation of the problem is Θ(logn), where n denotes the number of vertices in the graph.
Accurate upper-lower bounds on homogenized matrix by FFT-based Galerkin method
Vondřejc, Jaroslav; Marek, Ivo
2014-01-01
Accurate upper-lower bounds on homogenized matrix, arising from the unit cell problem for periodic media, are calculated for a scalar elliptic setting. Our approach builds on the recent variational reformulation of the Moulinec-Suquet (1994) Fast Fourier Transform (FFT) homogenization scheme by Vond\\v{r}ejc et al. (2014), which is based on the conforming Galerkin approximation with trigonometric polynomials. Upper-lower bounds are obtained by adjusting the primal-dual finite element framework developed independently by Dvo\\v{r}\\'{a}k (1993) and Wi\\c{e}ckowski (1995) to the FFT-based Galerkin setting. We show that the discretization procedure differs for odd and non-odd number of discretization points. In particular, thanks to the Helmholtz decomposition inherited from the continuous formulation, the duality structure is fully recovered for odd discretization. In the latter case, the more complex primal-dual structure is observed due to the trigonometric polynomials associated with the Nyquist frequencies. The...
Fang, Debin; Yu, Qian
2011-01-01
...) based on the Mizuno-Todd-Ye algorithm. The modified corrector steps in our algorithm cannot only draw the iteration point back to a narrower neighborhood of the center path but also reduce the duality gap...
A homogeneous interior-point algorithm for nonsymmetric convex conic optimization
Skajaa, Anders; Ye, Yinyu
2014-01-01
a new Runge–Kutta type second order search direction suitable for the general nonsymmetric conic problem. Moreover, quasi-Newton updating is used to reduce the number of factorizations needed, implemented so that data sparsity can still be exploited. Extensive and promising computational results...
Adapting histogram for automatic noise data removal in building interior point cloud data
Shukor, S. A. Abdul; Rushforth, E. J.
2015-05-01
3D point cloud data is now preferred by researchers to generate 3D models. These models can be used throughout a variety of applications including 3D building interior models. The rise of Building Information Modeling (BIM) for Architectural, Engineering, Construction (AEC) applications has given 3D interior modelling more attention recently. To generate a 3D model representing the building interior, a laser scanner is used to collect the point cloud data. However, this data often comes with noise. This is due to several factors including the surrounding objects, lighting and specifications of the laser scanner. This paper highlights on the usage of the histogram to remove the noise data. Histograms, used in statistics and probability, are regularly being used in a number of applications like image processing, where a histogram can represent the total number of pixels in an image at each intensity level. Here, histograms represent the number of points recorded at range distance intervals in various projections. As unwanted noise data has a sparser cloud density compared to the required data and is usually situated at a notable distance from the required data, noise data will have lower frequencies in the histogram. By defining the acceptable range using the average frequency, points below this range can be removed. This research has shown that these histograms have the capabilities to remove unwanted data from 3D point cloud data representing building interiors automatically. This feature will aid the process of data preprocessing in producing an ideal 3D model from the point cloud data.
Parameter Selection and Solution Algorithm for a Primal-dual Denoising Model%一种原始对偶去噪模型的参数选取与求解算法
田丹; 薛定宇; 陈大力
2014-01-01
基于对偶理论提出了一种用于图像去噪的原始对偶模型.从理论上分析了该模型与ROF(Rudin,Osher,Fatime)去噪模型的等价性,以及与具有鞍点结构的优化模型在结构上的相似性.使用一种求解鞍点问题的基于预解式的原始对偶算法对该模型进行求解,论证了确保算法收敛性的参数取值范围.在模型参数选取方面,基于Morozov偏差原理自适应选取调整参数,从而限制图像去噪寻优过程的可行域,保护图像特征.实验结果表明,提出的调整参数自适应选取策略能有效改善去噪效果,同时采用的基于预解式的原始对偶算法能有效快速收敛.
Explicit Sensor Network Localization using Semidefinite Representations and Facial Reductions
Krislock, Nathan
2010-01-01
The sensor network localization, SNL, problem in embedding dimension r, consists of locating the positions of wireless sensors, given only the distances between sensors that are within radio range and the positions of a subset of the sensors (called anchors). Current solution techniques relax this problem to a weighted, nearest, (positive) semidefinite programming, SDP, completion problem, by using the linear mapping between Euclidean distance matrices, EDM, and semidefinite matrices. The resulting SDP is solved using primal-dual interior point solvers, yielding an expensive and inexact solution. This relaxation is highly degenerate in the sense that the feasible set is restricted to a low dimensional face of the SDP cone, implying that the Slater constraint qualification fails. Cliques in the graph of the SNL problem give rise to this degeneracy in the SDP relaxation. In this paper, we take advantage of the absence of the Slater constraint qualification and derive a technique for the SNL problem, with exact ...
GPU implementation issues for fast unmixing of hyperspectral images
Legendre, Maxime; Capriotti, Luca; Schmidt, Frédéric; Moussaoui, Saïd; Schmidt, Albrecht
2013-04-01
Space missions usually use hyperspectral imaging techniques to analyse the composition of planetary surfaces. Missions such as ESA's Mars Express and Venus Express generate extensive datasets whose processing demands so far have exceeded the resources available to many researchers. To overcome this limitation, the challenge is to develop numerical methods allowing to exploit the potential of modern calculation tools. The processing of a hyperspectral image consists of the identification of the observed surface components and eventually the assessment of their fractional abundances inside each pixel area. In this latter case, the problem is referred to as spectral unmixing. This work focuses on a supervised unmixing approach where the relevant component spectra are supposed to be part of an available spectral library. Therefore, the question addressed here is reduced to the estimation of the fractional abundances, or abundance maps. It requires the solution of a large-scale optimization problem subject to linear constraints; positivity of the abundances and their partial/full additivity (sum less/equal to one). Conventional approaches to such a problem usually suffer from a high computational overhead. Recently, an interior-point optimization using a primal-dual approach has been proven an efficient method to solve this spectral unmixing problem at reduced computational cost. This is achieved with a parallel implementation based on Graphics Processing Units (GPUs). Several issues are discussed such as the data organization in memory and the strategy used to compute efficiently one global quantity from a large dataset in a parallel fashion. Every step of the algorithm is optimized to be GPU-efficient. Finally, the main steps of the global system for the processing of a large number of hyperspectral images are discussed. The advantage of using a GPU is demonstrated by unmixing a large dataset consisting of 1300 hyperspectral images from Mars Express' OMEGA instrument
陈厚合; 李国庆; 张芳晶
2014-01-01
In order to accurately assess the effect of wind farms on the available transfer capability (ATC), probabilistic available transfer capability of wind farm incorporated system is researched, and the change law of ATC with different wind farm incorporated system is analyzed in detail. First, the mathematical model of large scale wind farm is established based on the Weibull model of wind speed. Then, primal-dual interior point method is used to calculate the value of ATC in certain system operation mode. Finally, ATC probability assessment of wind power integrated system is achieved by Monte-carlo simulation method in a broad perspective. The simulation results show that the proposed algorithm can effectively assess the influence of wind farms to ATC, which has guiding functions for future expansion of the power grid and can provide effective reference information for the safety and economics evaluation of the system with wind farms.%为了准确评估风电场接入电网对系统可用输电能力(Available Transfer Capability, ATC)的影响，针对风电并网系统的概率可用输电能力计算展开研究，详细分析不同风电并网情况下ATC的变化规律。首先基于风速Weibull分布，建立了大型风电场输出功率数学模型；进而采用原-对偶内点法完成风电并网系统可用输电能力单一样板值的求解。在此基础上，采用蒙特卡罗仿真法从广义角度对风电并网系统的ATC进行概率评估。仿真结果表明，所提算法能够有效评估风电这种波动性电源对ATC的影响。研究成果可为风电并网系统安全经济性能评估提供有效参考信息，对未来电网规划扩建具有指导意义。
Xixin Wang
2012-01-01
Full Text Available ZrO2 nanotube arrays were prepared by anodization method in aqueous electrolyte containing (NH42SO4 and NH4F. The morphology and structure of nanotube arrays were characterized through scanning electron microscope, X-ray diffraction, and infrared spectra analysis. The zirconia nanotube arrays were used as catalyst in esterification reaction. The effects of calcination temperature and electrolyte concentration on catalytic esterification activity have been investigated in detail. Experiments indicate that nanotube arrays have highest catalytic activity when the concentration of (NH42SO4 is 1 mol/L, the concentration of NH4F is 1 wt%, and the calcination temperature is 400°C. Esterification reaction yield of as much as 97% could be obtained under optimal conditions.
Preconditioning for Allen–Cahn variational inequalities with non-local constraints
Blank, Luise
2012-06-01
The solution of Allen-Cahn variational inequalities with mass constraints is of interest in many applications. This problem can be solved both in its scalar and vector-valued form as a PDE-constrained optimization problem by means of a primal-dual active set method. At the heart of this method lies the solution of linear systems in saddle point form. In this paper we propose the use of Krylov-subspace solvers and suitable preconditioners for the saddle point systems. Numerical results illustrate the competitiveness of this approach. © 2012 Elsevier Inc.
Andrey Gnatov
2015-01-01
Full Text Available Recently repair and recovery vehicle body operations become more and more popular. A special place here is taken by equipment that provides performance of given repair operations. The most interesting things are methods for recovery of car body panels that allow the straightening without disassembling of car body panels and damaging of existing protective coating. Now, there are several technologies for repair and recovery of car body panels without their disassembly and dismantling. The most perspective is magnetic-pulse technology of external noncontact straightening. Basics of magnetic-pulse attraction, both ferromagnetic and nonferromagnetic thin-walled sheet metal, are explored. Inductor system calculation models of magnetic-pulse straightening tools are presented. Final analytical expressions for excited efforts calculation in the tools under consideration are introduced. According to the obtained analytical expressions, numerical evaluations of excited forces were executed. The volumetric epures of the attractive force radial distributions for different types of inductors were built. The practical testing of magnetic-pulse straightening with research tools is given. Using the results of the calculations we can create effective tools for an external magnetic-pulse straightening of car body panels.
Natural Preconditioning and Iterative Methods for Saddle Point Systems
Pestana, Jennifer
2015-01-01
© 2015 Society for Industrial and Applied Mathematics. The solution of quadratic or locally quadratic extremum problems subject to linear(ized) constraints gives rise to linear systems in saddle point form. This is true whether in the continuous or the discrete setting, so saddle point systems arising from the discretization of partial differential equation problems, such as those describing electromagnetic problems or incompressible flow, lead to equations with this structure, as do, for example, interior point methods and the sequential quadratic programming approach to nonlinear optimization. This survey concerns iterative solution methods for these problems and, in particular, shows how the problem formulation leads to natural preconditioners which guarantee a fast rate of convergence of the relevant iterative methods. These preconditioners are related to the original extremum problem and their effectiveness - in terms of rapidity of convergence - is established here via a proof of general bounds on the eigenvalues of the preconditioned saddle point matrix on which iteration convergence depends.
Iterative Methods for MPC on Graphical Processing Units
2012-01-01
The high oating point performance and memory bandwidth of Graphical Processing Units (GPUs) makes them ideal for a large number of computations which often arises in scientic computing, such as matrix operations. GPUs achieve this performance by utilizing massive par- allelism, which requires...... on their applicability for GPUs. We examine published techniques for iterative methods in interior points methods (IPMs) by applying them to simple test cases, such as a system of masses connected by springs. Iterative methods allows us deal with the ill-conditioning occurring in the later iterations of the IPM as well...... as to avoid the use of dense matrices, which may be too large for the limited memory capacity of current graphics cards....
Vanusa Alves de Sousa
2008-08-01
Full Text Available Este artigo apresenta a aplicação do método da função Lagrangiana-barreira relaxada ao problema de despacho ótimo de reativos, o qual é um problema não-linear não convexo e de grande porte. Nesta abordagem as restrições de desigualdade são tratadas pela associação dos métodos de barreira modificada e primal-dual barreira logarítmica. Essas restrições são transformadas em igualdades através de variáveis auxiliares positivas e são relaxadas pelo parâmetro de barreira. Uma função Lagrangiana é associada ao problema modificado. As condições necessárias de primeira-ordem são aplicadas gerando um sistema não-linear o qual é resolvido pelo método de Newton. A relaxação das variáveis auxiliares resulta na expansão da região factível do problema original, permitindo atingir o limite das restrições de desigualdade. Testes numéricos nos sistemas CESP 53 barras, o equivalente brasileiro sul-sudeste e o teste comparativo com o método primal-dual barreira logarítmica indicam que o método apresentado é eficiente na resolução do problema de despacho ótimo de reativos.This work presents the application of the relaxed barrier-Lagrangian function method to the optimal reactive dispatch problem, which is a nonlinear nonconvex and large problem. In this approach the inequality constraints are treated by the association of modified barrier and primal-dual logarithmic barrier method. Those constraints are transformed in equalities through positive auxiliary variables and are perturbed by the barrier parameter. A Lagrangian function is associated to the modified problem. The first-order necessary conditions are applied generating a non-linear system which is solved by Newton's method. The auxiliary variables perturbation result in an expansion of the feasible set of the original problem, allowing the limits of the inequality constraints to be reach. Numeric tests with the systems CESP 53 buses and the south
Stabilization of structure-preserving power networks with market dynamics
Stegink, Tjerk W; van der Schaft, Arjan J
2016-01-01
This paper studies the problem of maximizing the social welfare while stabilizing both the physical power network as well as the market dynamics. For the physical power grid a third-order structure-preserving model is considered involving both frequency and voltage dynamics. By applying the primal-dual gradient method to the social welfare problem, a distributed dynamic pricing algorithm in port-Hamiltonian form is obtained. After interconnection with the physical system a closed-loop port-Hamiltonian system of differential-algebraic equations is obtained, whose properties are exploited to prove local asymptotic stability of the optimal points.
Hitting Diamonds and Growing Cacti
Fiorini, Samuel; Pietropaoli, Ugo
2009-01-01
We consider the following problem: in a weighted graph, find a minimum cost set of vertices whose removal leaves a graph in which no two cycles share an edge. This NP-hard problem belongs to a general class of vertex deletion problems including the vertex cover problem and the feedback vertex set problem. We obtain a constant-factor approximation algorithm, based on the primal-dual method. Moreover, we show that the integrality gap of the natural LP relaxation of the problem is \\Theta(log n), where n denotes the number of vertices in the graph.
Award DE-FG02-04ER52655 Final Technical Report: Interior Point Algorithms for Optimization Problems
O' Leary, Dianne P. [Univ. of Maryland; Tits, Andre [Univ. of Maryland
2014-04-03
Over the period of this award we developed an algorithmic framework for constraint reduction in linear programming (LP) and convex quadratic programming (QP), proved convergence of our algorithms, and applied them to a variety of applications, including entropy-based moment closure in gas dynamics.
Interior Point Approach for Convex Quadratic Programming%凸二次规划问题的内点算法
阮喜珍
2003-01-01
提出了一类利用对数障碍函数法求解凸二次规划问题的内点算法,此算法在每次迭代中只需解一个等式约束的二次规划问题(或线性方程组系统),结构简单,易于计算,最后运用数值仿真测试验证了此方法的有效性.
Preconditioning for partial differential equation constrained optimization with control constraints
Stoll, Martin
2011-10-18
Optimal control problems with partial differential equations play an important role in many applications. The inclusion of bound constraints for the control poses a significant additional challenge for optimization methods. In this paper, we propose preconditioners for the saddle point problems that arise when a primal-dual active set method is used. We also show for this method that the same saddle point system can be derived when the method is considered as a semismooth Newton method. In addition, the projected gradient method can be employed to solve optimization problems with simple bounds, and we discuss the efficient solution of the linear systems in question. In the case when an acceleration technique is employed for the projected gradient method, this again yields a semismooth Newton method that is equivalent to the primal-dual active set method. We also consider the Moreau-Yosida regularization method for control constraints and efficient preconditioners for this technique. Numerical results illustrate the competitiveness of these approaches. © 2011 John Wiley & Sons, Ltd.
李星恕; 崔猛; 杨剑雄; 韩文霆; 熊秀芳
2014-01-01
为了实现植物根系结构形态的原位检测，植物根系单根的断层图像重建研究非常必要。该文应用动态电阻抗成像技术对土壤-树根模拟系统进行了图像重建，对重建图像进行二值化处理并求出树根在该系统中的位置坐标、面积和形状，并以树根的位置坐标、面积及形状的相对偏差为指标，分析了图像重建算法、土壤含水率2个因素对成像质量的影响。结果表明：电阻抗成像技术能够实现树木单根断层图像重建；将重建图像进行二值化处理，所得图像更加直观，便于定量评价成像质量；基于Newton单步残差正则化的一步牛顿误差重构（Newton’s one-step error reconsruction，NOSER）算法，比基于全变差正则化的主双-内点模式（primal dual-interior point method，PD-IPM）算法的成像质量好；土壤含水率越高成像质量越好。该研究为基于电阻抗成像技术的植物根系结构形态的图像重建提供参考。%Root architecture plays an important role in plant nutrient and moisture absorption, so the study on plant root architecture and growth pattern is crucial to improve ecological environment and plant productivity. It is also necessary to obtain root architecture of plant cheaply, fastly and easily. Electrical impedance tomography (EIT) was used to produce images according to electrical parameters distribution within the studied region. The electrical parameters were calculated using the resulted potentials on the electrodes by which sinusoidal electrical current was applied into the imaging domain. This method has been extensively developed for both medical and industrial use during the past decades as visualization and measurement technique, but rarely used in pant root architecture reconstruction. EIT has several advantages over other tomography techniques such as X-ray computed tomography (X-CT), magnetic resonance imaging (MRI) and ground penetrating radar
An Efficient Proximal-Gradient Method for Single and Multi-task Regression with Structured Sparsity
Chen, Xi; Kim, Seyoung; Peña, Javier; Carbonell, Jaime G; Xing, Eric P
2010-01-01
We consider the optimization problem of learning regression models with a mixed-norm penalty that is defined over overlapping groups to achieve structured sparsity. It has been previously shown that such penalty can encode prior knowledge on the input or output structure to learn an structured-sparsity pattern in the regression parameters. However, because of the non-separability of the parameters of the overlapping groups, developing an efficient optimization method has remained a challenge. An existing method casts this problem as a second-order cone programming (SOCP) and solves it by interior-point methods. However, this approach is computationally expensive even for problems of moderate size. In this paper, we propose an efficient proximal-gradient method that achieves a faster convergence rate and has a significantly lower time complexity than solving the SOCP formulation. Our method exploits the structure of the non-smooth structured-sparsity-inducing norm, introduces its smooth approximation, and solv...
Chen, Xueli; Yang, Defu; Zhang, Qitan; Liang, Jimin
2014-05-01
Even though bioluminescence tomography (BLT) exhibits significant potential and wide applications in macroscopic imaging of small animals in vivo, the inverse reconstruction is still a tough problem that has plagued researchers in a related area. The ill-posedness of inverse reconstruction arises from insufficient measurements and modeling errors, so that the inverse reconstruction cannot be solved directly. In this study, an l1/2 regularization based numerical method was developed for effective reconstruction of BLT. In the method, the inverse reconstruction of BLT was constrained into an l1/2 regularization problem, and then the weighted interior-point algorithm (WIPA) was applied to solve the problem through transforming it into obtaining the solution of a series of l1 regularizers. The feasibility and effectiveness of the proposed method were demonstrated with numerical simulations on a digital mouse. Stability verification experiments further illustrated the robustness of the proposed method for different levels of Gaussian noise.
Fernandes, Marco A.R., E-mail: mfernandes@fmb.unesp.b [Universidade Estadual Paulista Julio de Mesquita Filho (UNESP), Botucatu, SP (Brazil). Fac. de Medicina. Dept. de Dermatologia e Radioterapia; Fernandes, David M.; Florentino, Helenice O. [Universidade Estadual Paulista Julio de Mesquita Filho (UNESP), Botucatu, SP (Brazil). Inst. de Biociencias
2010-07-01
The work detaches the importance of the use of mathematical tools and computer systems for optimization of the planning in radiotherapy, seeking to the distribution of dose of appropriate radiation in the white volume that provides an ideal therapeutic rate between the tumor cells and the adjacent healthy tissues, extolled in the radiotherapy protocols. Examples of target volumes mathematically modeled are analyzed with the technique of linear programming, comparing the obtained results using the Simplex algorithm with those using the algorithm of Interior Points. The System Genesis II was used for obtaining of the isodose curves for the outline and geometry of fields idealized in the computer simulations, considering the parameters of a 10 MV photons beams. Both programming methods (Simplex and Interior Points) they resulted in a distribution of integral dose in the tumor volume and allow the adaptation of the dose in the critical organs inside of the restriction limits extolled. The choice of an or other method should take into account the facility and the need of limiting the programming time. The isodose curves, obtained with the Genesis II System, illustrate that the adjacent healthy tissues to the tumor receives larger doses than those reached in the computer simulations. More coincident values can be obtained altering the weights and some factors of minimization of the objective function. The prohibitive costs of the computer planning systems, at present available for radiotherapy, it motivates the researches to look for the implementation of simpler and so effective methods for optimization of the treatment plan. (author)
Optimization of structures subjected to dynamic load: deterministic and probabilistic methods
Élcio Cassimiro Alves
Full Text Available Abstract This paper deals with the deterministic and probabilistic optimization of structures against bending when submitted to dynamic loads. The deterministic optimization problem considers the plate submitted to a time varying load while the probabilistic one takes into account a random loading defined by a power spectral density function. The correlation between the two problems is made by one Fourier Transformed. The finite element method is used to model the structures. The sensitivity analysis is performed through the analytical method and the optimization problem is dealt with by the method of interior points. A comparison between the deterministic optimisation and the probabilistic one with a power spectral density function compatible with the time varying load shows very good results.
Input-constrained model predictive control via the alternating direction method of multipliers
Sokoler, Leo Emil; Frison, Gianluca; Andersen, Martin S.
2014-01-01
This paper presents an algorithm, based on the alternating direction method of multipliers, for the convex optimal control problem arising in input-constrained model predictive control. We develop an efficient implementation of the algorithm for the extended linear quadratic control problem (LQCP......) with input and input-rate limits. The algorithm alternates between solving an extended LQCP and a highly structured quadratic program. These quadratic programs are solved using a Riccati iteration procedure, and a structure-exploiting interior-point method, respectively. The computational cost per iteration...... is quadratic in the dimensions of the controlled system, and linear in the length of the prediction horizon. Simulations show that the approach proposed in this paper is more than an order of magnitude faster than several state-of-the-art quadratic programming algorithms, and that the difference in computation...
ON KARUSH-KUHN-TUCKER POINTS FOR A SMOOTHING METHOD IN SEMI-INFINITE OPTIMIZATION
Oliver Stein
2006-01-01
We study the smoothing method for the solution of generalized semi-infinite optimization problems from (O. Stein, G. Still: Solving semi-infinite optimization problems with interior point techniques, SIAM J. Control Optim., 42(2003), pp. 769-788). It is shown that Karush-Kuhn-Tucker points of the smoothed problems do not necessarily converge to a Karush-Kuhn-Tucker point of the original problem, as could be expected from results in (F. Facchinei, H. Jiang, L. Qi: A smoothing method for mathematical programs with equilibrium constraints, Math. Program., 85(1999), pp. 107-134). Instead, they might merely converge to a Fritz John point. We give, however, different additional assumptions which guarantee convergence to Karush-Kuhn-Tucker points.
Research on Design Method of the Full Form Ship with Minimum Thrust Deduction Factor
张宝吉; 缪爱琴; 张竹心
2015-01-01
In the preliminary design stage of the full form ships, in order to obtain a hull form with low resistance and maximum propulsion efficiency, an optimization design program for a full form ship with the minimum thrust deduction factor has been developed, which combined the potential flow theory and boundary layer theory with the optimization technique. In the optimization process, the Sequential Unconstrained Minimization Technique (SUMT) interior point method of Nonlinear Programming (NLP) was proposed with the minimum thrust deduction factor as the objective function. An appropriate displacement is a basic constraint condition, and the boundary layer separation is an additional one. The parameters of the hull form modification function are used as design variables. At last, the numerical optimization example for lines of after-body of 50000 DWT product oil tanker was provided, which indicated that the propulsion efficiency was improved distinctly by this optimal design method.
A Fast Condensing Method for Solution of Linear-Quadratic Control Problems
Frison, Gianluca; Jørgensen, John Bagterp
2013-01-01
In both Active-Set (AS) and Interior-Point (IP) algorithms for Model Predictive Control (MPC), sub-problems in the form of linear-quadratic (LQ) control problems need to be solved at each iteration. The solution of these sub-problems is usually the main computational effort. In this paper we...... consider a condensing (or state elimination) method to solve an extended version of the LQ control problem, and we show how to exploit the structure of this problem to both factorize the dense Hessian matrix and solve the system. Furthermore, we present two efficient implementations. The first...... implementation is formally identical to the Riccati recursion based solver and has a computational complexity that is linear in the control horizon length and cubic in the number of states. The second implementation has a computational complexity that is quadratic in the control horizon length as well...
Yerlikaya-Özkurt, Fatma; Askan, Aysegul; Weber, Gerhard-Wilhelm
2014-12-01
Ground Motion Prediction Equations (GMPEs) are empirical relationships which are used for determining the peak ground response at a particular distance from an earthquake source. They relate the peak ground responses as a function of earthquake source type, distance from the source, local site conditions where the data are recorded and finally the depth and magnitude of the earthquake. In this article, a new prediction algorithm, called Conic Multivariate Adaptive Regression Splines (CMARS), is employed on an available dataset for deriving a new GMPE. CMARS is based on a special continuous optimization technique, conic quadratic programming. These convex optimization problems are very well-structured, resembling linear programs and, hence, permitting the use of interior point methods. The CMARS method is performed on the strong ground motion database of Turkey. Results are compared with three other GMPEs. CMARS is found to be effective for ground motion prediction purposes.
含UPFC的电力系统最优潮流计算%OPTIMAL POWER FLOW COMPUTATION FOR POWER SYSTEM WITH UPFC
林声宏; 刘明波; 王晓村
2001-01-01
Because UPFC can control branch power flow and bus voltage magnitude, Additional equality and inequality constraints should be incorporated in optimal power flow model of power system with UPFC so that the optimization algorithm becomes more complex. A direct nonlinear primal -dual path following interior point algorithm to solve the OPF with UPFC is presented , and the optimization results of three test systems validate its effectiveness.%由于UPFC能够控制母线电压和线路潮流，包含UPFC的电力系统最优潮流模型中须引入附加的等式约束和不等式约束，增加了优化计算的复杂性。本文应用直接非线性原一对偶路径跟踪内点算法进行求解，并给出了3个试验系统的优化计算结果，验证该方法的有效性。
Inter ISO Market Coordination by Calculating Border Locational Marginal Prices
BABIC, A. B.
2013-05-01
Full Text Available In this paper the methodology for solving Locational Marginal Price (LMP differences (inconsistency of LMPs that arise at the boundary buses between separate power markets is proposed. The algorithm developed enables us to obtain consistent LMP values at the boundary buses between interconnected ISOs. A Primal-Dual Interior Point based optimal power flow (OPF is applied, with complete set of power system physical limit constraints, to solve a regional spot market. The OPF is implemented such that producer and consumer behaviors are modeled simultaneously, while the welfare is maximized. In this paper a generalized methodology for multiple ISOs case is proposed and later it is practically applied on two interconnected independent entities. The algorithm for approximation of cost coefficients of generators and dispatchable loads for neighboring ISOs is proposed. The developed algorithm enables participating ISOs to obtain LMPs at the boundary buses with other interconnected ISOs. By controlling interchange of electric power at the scheduled level, regional spot markets are resolved eliminating possible exercise of market power by individual interconnected ISOs. Results of proposed methodology are tested on the IEEE 118-bus power system.
Smoothing Proximal Gradient Method for General Structured Sparse Learning
Chen, Xi; Kim, Seyoung; Carbonell, Jaime G; Xing, Eric P
2012-01-01
We study the problem of learning high dimensional regression models regularized by a structured-sparsity-inducing penalty that encodes prior structural information on either input or output sides. We consider two widely adopted types of such penalties as our motivating examples: 1) overlapping group lasso penalty, based on the l1/l2 mixed-norm penalty, and 2) graph-guided fusion penalty. For both types of penalties, due to their non-separability, developing an efficient optimization method has remained a challenging problem. In this paper, we propose a general optimization approach, called smoothing proximal gradient method, which can solve the structured sparse regression problems with a smooth convex loss and a wide spectrum of structured-sparsity-inducing penalties. Our approach is based on a general smoothing technique of Nesterov. It achieves a convergence rate faster than the standard first-order method, subgradient method, and is much more scalable than the most widely used interior-point method. Numer...
A Quick and Affine Invariance Matching Method for Oblique Images
XIAO Xiongwu
2015-04-01
Full Text Available This paper proposed a quick, affine invariance matching method for oblique images. It calculated the initial affine matrix by making full use of the two estimated camera axis orientation parameters of an oblique image, then recovered the oblique image to a rectified image by doing the inverse affine transform, and left over by the SIFT method. We used the nearest neighbor distance ratio(NNDR, normalized cross correlation(NCC measure constraints and consistency check to get the coarse matches, then used RANSAC method to calculate the fundamental matrix and the homography matrix. And we got the matches that they were interior points when calculating the homography matrix, then calculated the average value of the matches' principal direction differences. During the matching process, we got the initial matching features by the nearest neighbor(NN matching strategy, then used the epipolar constrains, homography constrains, NCC measure constrains and consistency check of the initial matches' principal direction differences with the calculated average value of the interior matches' principal direction differences to eliminate false matches. Experiments conducted on three pairs of typical oblique images demonstrate that our method takes about the same time as SIFT to match a pair of oblique images with a plenty of corresponding points distributed evenly and an extremely low mismatching rate.
TAS: 89 0227: TAS Recovery Act - Optimization and Control of Electric Power Systems: ARRA
Chiang, Hsiao-Dong
2014-02-01
The name SuperOPF is used to refer several projects, problem formulations and soft-ware tools intended to extend, improve and re-define some of the standard methods of optimizing electric power systems. Our work included applying primal-dual interior point methods to standard AC optimal power flow problems of large size, as well as extensions of this problem to include co-optimization of multiple scenarios. The original SuperOPF problem formulation was based on co-optimizing a base scenario along with multiple post-contingency scenarios, where all AC power flow models and constraints are enforced for each, to find optimal energy contracts, endogenously determined locational reserves and appropriate nodal energy prices for a single period optimal power flow problem with uncertainty. This led to example non-linear programming problems on the order of 1 million constraints and half a million variables. The second generation SuperOPF formulation extends this by adding multiple periods and multiple base scenarios per period. It also incorporates additional variables and constraints to model load following reserves, ramping costs, and storage resources. A third generation of the multi-period SuperOPF, adds both integer variables and a receding horizon framework in which the problem type is more challenging (mixed integer), the size is even larger, and it must be solved more frequently, pushing the limits of currently available algorithms and solvers. The consideration of transient stability constraints in optimal power flow (OPF) problems has become increasingly important in modern power systems. Transient stability constrained OPF (TSCOPF) is a nonlinear optimization problem subject to a set of algebraic and differential equations. Solving a TSCOPF problem can be challenging due to (i) the differential-equation constraints in an optimization problem, (ii) the lack of a true analytical expression for transient stability in OPF. To handle the dynamics in TSCOPF, the set
Coordinated planning of substation expansion and BESS sizing%变电站扩容和电池储能系统容量配置的协调规划方法
李振文; 颜伟; 刘伟良; 荀吉辉
2013-01-01
A coordinated planning model of substation expansion and battery energy storage system (BESS) sizing is proposed, fully considering the effect of BESS charging and discharging on deferring substation expansion. Based on a typical distribution network and its daily load, the objective of the proposed model is to minimize the power purchase costs and the investment and operation costs of BESS and substation. The charging and discharging characteristics of BESS and the network security constraints are included. Candidate discrete/continuous expansion capacity are both considered. It is a multi-period nonlinear mixed-integer programming problem, containing integer variables especially when discrete expansion capacity is considered, which is converted to a continuous optimization problem with complementarities constraints. The decomposed primal-dual interior point method is used to solve the model iteratively and coordinatively, which is decomposed to several single period optimization problems. The case results show that the proposed method can effectively reduce the investment of grid expansion, and optimize the sizing of BESS.% 充分考虑电池储能系统（BESS）的充放电效益对变电站扩容建设的推迟作用，建立了变电站扩容建设和BESS容量配置的协调规划模型。新模型基于一个含风电场的典型地区配电网络及其日负荷曲线，考虑了购电费用和BESS与变电站扩容的综合投资运行费用目标，同时还考虑了BESS的充放电特点和网络的安全约束。其中对于变电站扩容容量包含给定待选与连续可调两种情况。该模型是一个多时段非线性规划问题，在变电站扩容容量为给定待选的情况下还包含整数变量，需将其转换为含互补约束条件的连续优化问题，再采用原对偶解耦内点法将其解耦为单时段优化问题进行协调迭代求解。算例结果表明该方法可以有效减小电网的扩容投资，并实
Split Bregman's algorithm for three-dimensional mesh segmentation
Habiba, Nabi; Ali, Douik
2016-05-01
Variational methods have attracted a lot of attention in the literature, especially for image and mesh segmentation. The methods aim at minimizing the energy to optimize both edge and region detections. We propose a spectral mesh decomposition algorithm to obtain disjoint but meaningful regions of an input mesh. The related optimization problem is nonconvex, and it is very difficult to find a good approximation or global optimum, which represents a challenge in computer vision. We propose an alternating split Bregman algorithm for mesh segmentation, where we extended the image-dedicated model to a three-dimensional (3-D) mesh one. By applying our scheme to 3-D mesh segmentation, we obtain fast solvers that can outperform various conventional ones, such as graph-cut and primal dual methods. A consistent evaluation of the proposed method on various public domain 3-D databases for different metrics is elaborated, and a comparison with the state-of-the-art is performed.
An Infeasible-Interior-Point Algorithms for Separable Convex Quadratic Programming%可分凸二次规划的不可行内点算法
李健; 费浦生; 邱巍
2000-01-01
给出了可分凸二次规划的不可行内点算法,并证明了该算法在O(n2L)次迭代之后,或者收敛到问题的一个近似最优解,或者说明该问题在某个较大区域内无最优解.
An Infeasible Interior Point Algorithm for Convex Quadratic Programming%求解凸二次规划问题的不可行内点算法
邱巍; 费浦生; 王言金
2002-01-01
该文对一般的凸二次规划问题,给出了一个不可行内点算法,并证明了该算法经过O(n2L)步迭代之后,要么得到问题的一个近似最优解,要么说明该问题在某个较大的区域内无解.
邓莉荣; 孙宏斌; 陈润泽; 郭庆来
2016-01-01
ABSTRACT:In order to more accurately reflect the value of different energy sources in the integrated energy system, better motivate users to a reasonable energy use behavior, a new multiple energy coupling pricing mechanism—nodal energy price, was put forward. Detailed research on the nodal energy price in the combined heat and power system was conducted. Firstly, according to nodal price, the definition and classification of nodal energy price were given. The energy price could be divided into three parts: energy demand component, congestion component and multi-energy coupling component. An optimal power flow model of cogeneration system was proposed and the primal dual interior point method was used to solve this problem. The Lagrange multipliers of corresponding node power balance equations in power system and heat-supply system could be taken as nodal electricity price and nodal heat price, separately. Simulation results show that the nodal energy price well explain the energy price influencing factors in integrated energy system: the energy supply node price can be determined by the energy demand component and multi-energy coupling component, while the load node price on the basis of the energy supply node price can be superimposed congestion component.%为更准确地体现综合能源系统中不同能源的价值，更好地激励用户合理用能，提出了一种新的多种能源耦合定价机制——节点能价，并在热电联供系统中对节点能价进行了研究。首先，类比节点电价，给出了节点能价的定义和分类。将节点能价分为3部分：生产边际成本、传输阻塞成本和多能耦合成本。建立了热电联供系统的最优潮流模型，采用原对偶内点法进行求解，以电力系统节点功率平衡方程和热力系统节点功率平衡方程所对应的拉格朗日乘子作为各节点的节点电价和节点热价。算例结果表明节点能价很好地解释了综合能源系统中
沈俭荣; 文云峰; 郭创新; 马士聪; 贺庆
2016-01-01
随着分布式电源在用户端的广泛接入，互联微网间的调度问题将呈现非合作特性，难以直接通过集中优化求解。鉴于此，文中结合电力市场双边交易机制，提出了一种基于产消方式的互联微网协同自治运行策略。该策略充分尊重市场运行的客观规律，通过挖掘电力供需本质以及主动能量管理为配电网的经济优化调度提供依据。针对该策略设计了一种双层优化算法：下层优化问题通过计算微网系统自治状态下的节点边际电价和需求曲线以寻求互联微网协同运行的平衡点；上层优化问题基于原—对偶内点法对微网出力及联络线功率进行优化。算例仿真结果验证了互联微网分散协同运行策略的正确性及其用于主动配电网实时优化调度的有效性。%With the increasing penetration of distributed generators on the demand side, the dispatch problem among interconnected microgrids (MGs) is difficult to solve by directly optimizing its non-cooperative features.In view of this,this paper proposes a prosumer-based autonomous-synergetic operation strategy for interconnected MGs by integrating the bilateral trade mechanism of electricity market.With full respect for the obj ective law of market operation,this strategy can provide a reference for economical dispatch of distribution networks by mining the essence of power transaction and active energy management.A two-level optimization algorithm is designed to realize the strategy,in the lower level of which,the local marginal price and supply/demand curves of autonomous MGs are calculated to seek the equilibrium point of synergetic operation of interconnected MGs.In the upper-level,the primal-dual interior-point method is employed to optimize the inj ection power of MGs and tie-line power.Simulation results show the correctness of the strategy proposed and its effectiveness of application in the real-time optimization dispatch of
Automatic brain tumor segmentation with a fast Mumford-Shah algorithm
Müller, Sabine; Weickert, Joachim; Graf, Norbert
2016-03-01
We propose a fully-automatic method for brain tumor segmentation that does not require any training phase. Our approach is based on a sequence of segmentations using the Mumford-Shah cartoon model with varying parameters. In order to come up with a very fast implementation, we extend the recent primal-dual algorithm of Strekalovskiy et al. (2014) from the 2D to the medically relevant 3D setting. Moreover, we suggest a new confidence refinement and show that it can increase the precision of our segmentations substantially. Our method is evaluated on 188 data sets with high-grade gliomas and 25 with low-grade gliomas from the BraTS14 database. Within a computation time of only three minutes, we achieve Dice scores that are comparable to state-of-the-art methods.
Sequential anomaly detection in the presence of noise and limited feedback
Raginsky, Maxim; Silva, Jorge; Willett, Rebecca
2009-01-01
This paper describes a method for detecting anomalies from sequentially observed and potentially noisy data. The proposed approach consists of two main elements: (1) filtering, or assigning a belief or likelihood to each successive measurement based upon our ability to predict it from previous noisy observations, and (2) hedging, or flagging potential anomalies by comparing the current belief against a time-varying and data-adaptive threshold. The threshold is adjusted based on the available feedback from an end user. Our algorithms, inspired by recent work on online convex programming, do not require computing posterior distributions given all current observations and involve simple primal-dual parameter updates. At the heart of the proposed approach lie exponential-family models which can be used in a wide variety of contexts and applications, and which yield methods that achieve sublinear per-round regret against both static and slowly varying product distributions with marginals drawn from the same expone...
MILP Approach for Bilevel Transmission and Reactive Power Planning Considering Wind Curtailment
Ugranli, Faruk; Karatepe, Engin; Nielsen, Arne Hejde
2017-01-01
In this study, two important planning problems in power systems that are transmission expansion and reactive power are formulated as a mixed-integer linear programming taking into account the bilevel structure due to the consideration of market clearing under several load-wind scenarios....... The objective of the proposed method is to minimize the installation cost of transmission lines, reactive power sources, and the annual operation costs of conventional generators corresponding to the curtailed wind energy while maintaining the reliable system operation. Lower level problems of the bilevel...... structure are designated for the market clearing which is formulated by using the linearized optimal power flow equations. In order to obtain mixed-integer linear programming formulation, the so-called lower level problems are represented by using primal-dual formulation. By using the proposed method, power...
Optimization schemes for the inversion of Bouguer gravity anomalies
Zamora, Azucena
associated with structural changes [16]; therefore, it complements those geophysical methods with the same depth resolution that sample a different physical property (e.g. electromagnetic surveys sampling electric conductivity) or even those with different depth resolution sampling an alternative physical property (e.g. large scale seismic reflection surveys imaging the crust and top upper mantle using seismic velocity fields). In order to improve the resolution of Bouguer gravity anomalies, and reduce their ambiguity and uncertainty for the modeling of the shallow crust, we propose the implementation of primal-dual interior point methods for the optimization of density structure models through the introduction of physical constraints for transitional areas obtained from previously acquired geophysical data sets. This dissertation presents in Chapter 2 an initial forward model implementation for the calculation of Bouguer gravity anomalies in the Porphyry Copper-Molybdenum (Cu-Mo) Copper Flat Mine region located in Sierra County, New Mexico. In Chapter 3, we present a constrained optimization framework (using interior-point methods) for the inversion of 2-D models of Earth structures delineating density contrasts of anomalous bodies in uniform regions and/or boundaries between layers in layered environments. We implement the proposed algorithm using three different synthetic gravitational data sets with varying complexity. Specifically, we improve the 2-dimensional density structure models by getting rid of unacceptable solutions (geologically unfeasible models or those not satisfying the required constraints) given the reduction of the solution space. Chapter 4 shows the results from the implementation of our algorithm for the inversion of gravitational data obtained from the area surrounding the Porphyry Cu-Mo Cooper Flat Mine in Sierra County, NM. Information obtained from previous induced polarization surveys and core samples served as physical constraints for the
A New Multiphase Soft Segmentation with Adaptive Variants
Hongyuan Wang
2013-01-01
segmentation model for nearly piecewise constant images based on stochastic principle, where pixel intensities are modeled as random variables with mixed Gaussian distribution. The novelty of this paper lies in three aspects. First, unlike some existing models where the mean of each phase is modeled as a constant and the variances for different phases are assumed to be the same, the mean for each phase in the Gaussian distribution in this paper is modeled as a product of a constant and a bias field, and different phases are assumed to have different variances, which makes the model more flexible. Second, we develop a bidirection projected primal dual hybrid gradient (PDHG algorithm for iterations of membership functions. Third, we also develop a novel algorithm for explicitly computing the projection from RK to simplex ΔK-1 for any dimension K using dual theory, which is more efficient in both coding and implementation than existing projection methods.
Scheduling and congestion control for wireless internet
Wang, Xin
2014-01-01
This brief proposes that the keys to internet cross-layer optimization are the development of non-standard implicit primal-dual solvers for underlying optimization problems, and design of jointly optimal network protocols as decomposition of such solvers. Relying on this novel design-space oriented approach, the author develops joint TCP congestion control and wireless-link scheduling schemes for wireless applications over Internet with centralized and distributed (multi-hop) wireless links. Different from the existing solutions, the proposed schemes can be asynchronously implemented without message passing among network nodes; thus they are readily deployed with current infrastructure. Moreover, global convergence/stability of the proposed schemes to optimal equilibrium is established using the Lyapunov method in the network fluid model. Simulation results are provided to evaluate the proposed schemes in practical networks.
Design and Stability of Load-Side Primary Frequency Control in Power Systems
Zhao, CH; Topcu, U; Li, N; Low, S
2014-05-01
We present a systematic method to design ubiquitous continuous fast-acting distributed load control for primary frequency regulation in power networks, by formulating an optimal load control (OLC) problem where the objective is to minimize the aggregate cost of tracking an operating point subject to power balance over the network. We prove that the swing dynamics and the branch power flows, coupled with frequency-based load control, serve as a distributed primal-dual algorithm to solve OLC. We establish the global asymptotic stability of a multimachine network under such type of load-side primary frequency control. These results imply that the local frequency deviations on each bus convey exactly the right information about the global power imbalance for the loads to make individual decisions that turn out to be globally optimal. Simulations confirm that the proposed algorithm can rebalance power and resynchronize bus frequencies after a disturbance with significantly improved transient performance.
Minimum-Energy Wireless Real-Time Multicast by Joint Network Coding and Scheduling Optimization
Guoping Tan
2015-01-01
Full Text Available For real-time multicast services over wireless multihop networks, to minimize the energy of transmissions with satisfying the requirements of a fixed data rate and high reliabilities, we construct a conflict graph based framework by joint optimizing network coding and scheduling. Then, we propose a primal-dual subgradient optimization algorithm by random sampling K maximal stable sets in a given conflict graph. This method transforms the NP-hard scheduling subproblem into a normal linear programming problem to obtain an approximate solution. The proposed algorithm only needs to adopt centralized technique for solving the linear programming problem while all of the other computations can be distributed. The simulation results show that, comparing with the existing algorithm, this algorithm can not only achieve about 20% performance gain, but also have better performance in terms of convergence and robustness.
Compliant landing of a trotting quadruped robot based on hybrid motion/force robust control
郎琳; 王剑; 韦庆; 马宏绪
2016-01-01
A compliant landing strategy for a trotting quadruped robot on unknown rough terrains based on contact force control is presented. Firstly, in order to lower the disturbance caused by the landing impact force, a landing phase is added between the swing phase and the stance phase, where the desired contact force is set as a small positive constant. Secondly, the joint torque optimization of the stance legs is formulated as a quadratic programming (QP) problem subject to equality and inequality/bound constraints. And a primal-dual dynamical system solver based on linear variational inequalities (LVI) is applied to solve this QP problem. Furthermore, based on the optimization results, a hybrid motion/force robust controller is designed to realize the tracking of the contact force, while the constraints of the stance feet landing angles are fulfilled simultaneously. Finally, the experiments are performed to validate the proposed methods.
Gao, Hao
2016-04-01
For the treatment planning during intensity modulated radiation therapy (IMRT) or volumetric modulated arc therapy (VMAT), beam fluence maps can be first optimized via fluence map optimization (FMO) under the given dose prescriptions and constraints to conformally deliver the radiation dose to the targets while sparing the organs-at-risk, and then segmented into deliverable MLC apertures via leaf or arc sequencing algorithms. This work is to develop an efficient algorithm for FMO based on alternating direction method of multipliers (ADMM). Here we consider FMO with the least-square cost function and non-negative fluence constraints, and its solution algorithm is based on ADMM, which is efficient and simple-to-implement. In addition, an empirical method for optimizing the ADMM parameter is developed to improve the robustness of the ADMM algorithm. The ADMM based FMO solver was benchmarked with the quadratic programming method based on the interior-point (IP) method using the CORT dataset. The comparison results suggested the ADMM solver had a similar plan quality with slightly smaller total objective function value than IP. A simple-to-implement ADMM based FMO solver with empirical parameter optimization is proposed for IMRT or VMAT.
Chen, Xueli, E-mail: xlchen@xidian.edu.cn, E-mail: jimleung@mail.xidian.edu.cn; Yang, Defu; Zhang, Qitan; Liang, Jimin, E-mail: xlchen@xidian.edu.cn, E-mail: jimleung@mail.xidian.edu.cn [School of Life Science and Technology, Xidian University, Xi' an 710071 (China); Engineering Research Center of Molecular and Neuro Imaging, Ministry of Education (China)
2014-05-14
Even though bioluminescence tomography (BLT) exhibits significant potential and wide applications in macroscopic imaging of small animals in vivo, the inverse reconstruction is still a tough problem that has plagued researchers in a related area. The ill-posedness of inverse reconstruction arises from insufficient measurements and modeling errors, so that the inverse reconstruction cannot be solved directly. In this study, an l{sub 1/2} regularization based numerical method was developed for effective reconstruction of BLT. In the method, the inverse reconstruction of BLT was constrained into an l{sub 1/2} regularization problem, and then the weighted interior-point algorithm (WIPA) was applied to solve the problem through transforming it into obtaining the solution of a series of l{sub 1} regularizers. The feasibility and effectiveness of the proposed method were demonstrated with numerical simulations on a digital mouse. Stability verification experiments further illustrated the robustness of the proposed method for different levels of Gaussian noise.
张国梁; 侯晓鹏; 苗虎; 安源; 周玉成; 姚永和
2014-01-01
Algorithms which were available in most literatures for whole layout of large scale rectangular parts gave solutions that resulted in frequent change of saw line and therefore dropped sawing velocity down. To solve this problem, a grouping and dimension-reducing heuristic rule which took areas of rectangular parts as priority was put forward in this paper. According to this rule,no more than three kinds of rectangular parts were considered in each layout calculation. Corresponding mathematical model was set up. Hybrid punishment function that was the combination of interior point method and exterior point one was applied to deal with constrains. Genetic algorithm ( GA) was adopted to search global optimal solution for layout. It was proved by example that the algorithm used in this paper could provide layout solution which exactly fulfilled guillotine cutting requirement and had saw line in order and therefore was useful to increase of sawing efficiency.
A SCALED CENTRAL PATH FOR LINEAR PROGRAMMING
Ya-xiang Yuan
2001-01-01
Interior point methods are very efficient methods for solving large scale linear programming problems. The central path plays a very important role in interior point methods. In this paper we propose a new central path, which scales the variables. Thus it has the advantage of forcing the path to have roughly the same distance from each active constraint boundary near the solution.
Dose domain regularization of MLC leaf patterns for highly complex IMRT plans
Nguyen, Dan; Yu, Victoria Y.; Ruan, Dan; Cao, Minsong; Low, Daniel A.; Sheng, Ke, E-mail: ksheng@mednet.ucla.edu [Department of Radiation Oncology, University of California Los Angeles, Los Angeles, California 90095 (United States); O’Connor, Daniel [Department of Mathematics, University of California Los Angeles, Los Angeles, California 90095 (United States)
2015-04-15
Purpose: The advent of automated beam orientation and fluence optimization enables more complex intensity modulated radiation therapy (IMRT) planning using an increasing number of fields to exploit the expanded solution space. This has created a challenge in converting complex fluences to robust multileaf collimator (MLC) segments for delivery. A novel method to regularize the fluence map and simplify MLC segments is introduced to maximize delivery efficiency, accuracy, and plan quality. Methods: In this work, we implemented a novel approach to regularize optimized fluences in the dose domain. The treatment planning problem was formulated in an optimization framework to minimize the segmentation-induced dose distribution degradation subject to a total variation regularization to encourage piecewise smoothness in fluence maps. The optimization problem was solved using a first-order primal-dual algorithm known as the Chambolle-Pock algorithm. Plans for 2 GBM, 2 head and neck, and 2 lung patients were created using 20 automatically selected and optimized noncoplanar beams. The fluence was first regularized using Chambolle-Pock and then stratified into equal steps, and the MLC segments were calculated using a previously described level reducing method. Isolated apertures with sizes smaller than preset thresholds of 1–3 bixels, which are square units of an IMRT fluence map from MLC discretization, were removed from the MLC segments. Performance of the dose domain regularized (DDR) fluences was compared to direct stratification and direct MLC segmentation (DMS) of the fluences using level reduction without dose domain fluence regularization. Results: For all six cases, the DDR method increased the average planning target volume dose homogeneity (D95/D5) from 0.814 to 0.878 while maintaining equivalent dose to organs at risk (OARs). Regularized fluences were more robust to MLC sequencing, particularly to the stratification and small aperture removal. The maximum and
季萍; 李鑫; 张明望
2014-01-01
对P*(κ)线性互补问题提出了一种自适应全-Newton步不可行内点算法.算法是对Mansouri等人(H.Mansouri and M.Pirhaji in Journal of Operations Research Society of China 1:523-536,2013)提出的单调线性互补问题的自适应不可行内点算法的推广.在算法的每一次迭代中,障碍校正参数θ的取值并不固定,它总在1/(51n(1+4κ)2)和1/(14n(1+4κ)2)之间取满足算法要求的最大值,使得算法快速收敛于问题的一个ε-近似解.
龚小玉; 张明望
2008-01-01
基于对数变换和不可行内点算法,对凸二次规划提出了一种新的迭代方向原始-对偶不可行内点算法,并证明了算法的全局收敛性和多项式复杂性,该算法可以看做近期Pan等人关于线性规划算法的推广.
葛仁东; 刘胜蓝; 董莹
2010-01-01
对一类利用对数障碍函数法求解凸二次规划问题的内点算法给出了全局收敛定理的证明,同时指出该算法并没有考虑到避免Maratos效应,因此很难有超线性收敛的结论,但是由于该算法简单,计算量少,故对小规模问题依然是有效的.
梁昔明
2002-01-01
@@ 1引言 二次规划问题的求解是数学规划和工业应用等领域的一个重要课题,同时也是解一般非线性规划问题的序列二次规划算法的关键.求解二次规划问题的早期技术是利用线性规划问题的单纯形方法求解二次规划问题的KKT最优性必要条件[1].这类算法比较直观,但在处理不等式约束时,松弛变量的引进很容易导致求解过程的明显减慢.
龚小玉; 张明望
2007-01-01
基于代数等价变换和在KMM算法的框架基础上,在原始一对偶内点方法的牛顿方程里嵌入一种自调节功能.从而对凸二次规划提出了一种新的迭代方向的不可行内点算法,并证明了算法的全局收敛性.
谌永荣
2007-01-01
提出了一个求解框式约束凸二次规划问题的势下降内点算法,它利用Armijo非精确线性搜索技巧进行线搜索,同时使势函数的值减少,并证明了算法的全局收敛性.
Nayfeh, Ali H
2008-01-01
1. Introduction 1 2. Straightforward Expansions and Sources of Nonuniformity 23 3. The Method of Strained Coordinates 56 4. The Methods of Matched and Composite Asymptotic Expansions 110 5. Variation of Parameters and Methods of Averaging 159 6. The Method of Multiple Scales 228 7. Asymptotic Solutions of Linear Equations 308 References and Author Index 387 Subject Index 417
A note on Johnson, Minkoff and Phillips' algorithm for the Prize-Collecting Steiner Tree Problem
Feofiloff, Paulo; Ferreira, Carlos E; de Pina, Jose Coelho
2010-01-01
The primal-dual scheme has been used to provide approximation algorithms for many problems. Goemans and Williamson gave a (2-1/(n-1))-approximation for the Prize-Collecting Steiner Tree Problem that runs in O(n^3 log n) time. it applies the primal-dual scheme once for each of the n vertices of the graph. Johnson, Minkoff and Phillips proposed a faster implementation of Goemans and Williamson's algorithm. We give a proof that the approximation ratio of this implementation is exactly 2.
Joan Duran
2016-04-01
Full Text Available This paper deals with the analysis, implementation, and comparison of several vector-valued total variation (TV methods that extend the Rudin-Osher-Fatemi variational model to color images. By considering the discrete gradient of a multichannel image as a 3D structure matrix with dimensions corresponding to the spatial extend, the differences to other pixels and the color channels, we introduce in [J. Duran, M. Moeller, C. Sbert, and D. Cremers, 'Collaborative Total Variation: A General Framework for Vectorial TV Models', SIAM Journal on Imaging Sciences, 9(1, pp.116-151, 2016] collaborative sparsity enforcing norms for penalizing the resulting tensor. We call this class of regularizations collaborative total variation (CTV. We first analyze the denoising properties of each collaborative norm for suppressing color artifacts while preserving image features and aligning edges. We then describe the primal-dual hybrid gradient method for solving the minimization problem in detail. The resulting CTV–L2 variational model can successfully be applied to many image processing tasks. On the one hand, an extensive performance comparison of several collaborative norms for color image denoising is provided. On the other hand, we analyze the ability of different CTV methods for decomposing a multichannel image into a cartoon and a textural part. Finally, we also include a short discussion on alternative minimization methods and compare their computational efficiency.
Multi-class DTI Segmentation: A Convex Approach.
Xie, Yuchen; Chen, Ting; Ho, Jeffrey; Vemuri, Baba C
2012-10-01
In this paper, we propose a novel variational framework for multi-class DTI segmentation based on global convex optimization. The existing variational approaches to the DTI segmentation problem have mainly used gradient-descent type optimization techniques which are slow in convergence and sensitive to the initialization. This paper on the other hand provides a new perspective on the often difficult optimization problem in DTI segmentation by providing a reasonably tight convex approximation (relaxation) of the original problem, and the relaxed convex problem can then be efficiently solved using various methods such as primal-dual type algorithms. To the best of our knowledge, such a DTI segmentation technique has never been reported in literature. We also show that a variety of tensor metrics (similarity measures) can be easily incorporated in the proposed framework. Experimental results on both synthetic and real diffusion tensor images clearly demonstrate the advantages of our method in terms of segmentation accuracy and robustness. In particular, when compared with existing state-of-the-art methods, our results demonstrate convincingly the importance as well as the benefit of using more refined and elaborated optimization method in diffusion tensor MR image segmentation.
[SIAM conference on optimization
1992-05-10
Abstracts are presented of 63 papers on the following topics: large-scale optimization, interior-point methods, algorithms for optimization, problems in control, network optimization methods, and parallel algorithms for optimization problems.
关于双航段收益管理网络上投标价格法的分析%Analysis of Bid-Price Control for a Two-Leg Airline Revenue Management Network
贺洪智
2015-01-01
本文提出了双航段网络上投标价格法的三种性质：经济互补性、原始－对偶模型解之间的关系和系统的单调性。这些性质可以很好地帮助收益管理人员理解所操作的收益管理系统，从而提升人机互动的效果。%The bid-price method is the most commonly used revenue management method in today’ s airlines. The revenue management staff on the front desk usually doesn ’ t know the internal principle of revenue management systems.This paper puts forward three characteristics of bid-price method of the two-leg revenue management sys-tem:economic complementarity , relationship between the primal-dual solutions , and the monotonicity of the sys-tem.These properties can well enhance the revenue management staff ’ s understanding toward the revenue manage-ment system they operate .
Chorin, A.J. [California Univ., Berkeley, CA (United States). Dept. of Mathematics]|[Lawrence Berkeley Lab., CA (United States)
1993-06-01
Vortex methods originated from the observation that in incompressible inviscid flow vorticity (or, more accurately, circulation) is a conserved quantity, as can be readily deduced from the absence of tangential stresses. Thus, if the vorticity is known at time t=0, one can find the flow at a later time by simply following the vorticity. In this narrow context, a vortex method is a numerical method that follows vorticity. The author restricts himself in these lectures to a special class of numerical vortex methods, those that are based on a Lagrangian transport of vorticity in hydrodynamics by smoothed particles (blobs) and those whose analysis contributes to the understanding of blob methods. Blob methods started in the 1930`s.
Kim, Young Shik; Lee, Kyung Woon; Kim, Oak Hwan; Kim, Dae Kyung [Korea Institute of Geology Mining and Materials, Taejon (Korea, Republic of)
1996-12-01
The reducing coal market has been enforcing the coal industry to make exceptional rationalization and restructuring efforts since the end of the eighties. To the competition from crude oil and natural gas has been added the growing pressure from rising wages and rising production cost as the workings get deeper. To improve the competitive position of the coal mines against oil and gas through cost reduction, studies to improve mining system have been carried out. To find fields requiring improvements most, the technologies using in Tae Bak Colliery which was selected one of long running mines were investigated and analyzed. The mining method appeared the field needing improvements most to reduce the production cost. The present method, so-called inseam roadway caving method presently is using to extract the steep and thick seam. However, this method has several drawbacks. To solve the problems, two mining methods are suggested for a long term and short term method respectively. Inseam roadway caving method with long-hole blasting method is a variety of the present inseam roadway caving method modified by replacing timber sets with steel arch sets and the shovel loaders with chain conveyors. And long hole blasting is introduced to promote caving. And pillar caving method with chock supports method uses chock supports setting in the cross-cut from the hanging wall to the footwall. Two single chain conveyors are needed. One is installed in front of chock supports to clear coal from the cutting face. The other is installed behind the supports to transport caved coal from behind. This method is superior to the previous one in terms of safety from water-inrushes, production rate and productivity. The only drawback is that it needs more investment. (author). 14 tabs., 34 figs.
Wagner, Falko Jens; Poulsen, Mikael Zebbelin
1999-01-01
When trying to solve a DAE problem of high index with more traditional methods, it often causes instability in some of the variables, and finally leads to breakdown of convergence and integration of the solution. This is nicely shown in [ESF98, p. 152 ff.].This chapter will introduce projection...... methods as a way of handling these special problems. It is assumed that we have methods for solving normal ODE systems and index-1 systems....
Berezin, I S
1965-01-01
Computing Methods, Volume 2 is a five-chapter text that presents the numerical methods of solving sets of several mathematical equations. This volume includes computation sets of linear algebraic equations, high degree equations and transcendental equations, numerical methods of finding eigenvalues, and approximate methods of solving ordinary differential equations, partial differential equations and integral equations.The book is intended as a text-book for students in mechanical mathematical and physics-mathematical faculties specializing in computer mathematics and persons interested in the
96 International Conference on Nonlinear Programming
1998-01-01
About 60 scientists and students attended the 96' International Conference on Nonlinear Programming, which was held September 2-5 at Institute of Compu tational Mathematics and Scientific/Engineering Computing (ICMSEC), Chi nese Academy of Sciences, Beijing, China. 25 participants were from outside China and 35 from China. The conference was to celebrate the 60's birthday of Professor M.J.D. Powell (Fellow of Royal Society, University of Cambridge) for his many contributions to nonlinear optimization. On behalf of the Chinese Academy of Sciences, vice president Professor Zhi hong Xu attended the opening ceremony of the conference to express his warm welcome to all the participants. After the opening ceremony, Professor M.J.D. Powell gave the keynote lecture "The use of band matrices for second derivative approximations in trust region methods". 13 other invited lectures on recent advances of nonlinear programming were given during the four day meeting: "Primal-dual methods for nonconvex optimization" by...
Interferometric radio transient reconstruction in compressed sensing framework
Jiang, M; Starck, J -L; Corbel, S; Tasse, C
2015-01-01
Imaging by aperture synthesis from interferometric data is a well-known, but is a strong ill-posed inverse problem. Strong and faint radio sources can be imaged unambiguously using time and frequency integration to gather more Fourier samples of the sky. However, these imagers assumes a steady sky and the complexity of the problem increases when transients radio sources are also present in the data. Hopefully, in the context of transient imaging, the spatial and temporal information are separable which enable extension of an imager fit for a steady sky. We introduce independent spatial and temporal wavelet dictionaries to sparsely represent the transient in both spatial domain and temporal domain. These dictionaries intervenes in a new reconstruction method developed in the Compressed Sensing (CS) framework and using a primal-dual splitting algorithm. According to the preliminary tests in different noise regimes, this new "Time-agile" (or 2D-1D) method seems to be efficient in detecting and reconstructing the...
Localized Multiple Kernel Learning Via Sample-Wise Alternating Optimization.
Han, Yina; Yang, Kunde; Ma, Yuanliang; Liu, Guizhong
2014-01-01
Our objective is to train support vector machines (SVM)-based localized multiple kernel learning (LMKL), using the alternating optimization between the standard SVM solvers with the local combination of base kernels and the sample-specific kernel weights. The advantage of alternating optimization developed from the state-of-the-art MKL is the SVM-tied overall complexity and the simultaneous optimization on both the kernel weights and the classifier. Unfortunately, in LMKL, the sample-specific character makes the updating of kernel weights a difficult quadratic nonconvex problem. In this paper, starting from a new primal-dual equivalence, the canonical objective on which state-of-the-art methods are based is first decomposed into an ensemble of objectives corresponding to each sample, namely, sample-wise objectives. Then, the associated sample-wise alternating optimization method is conducted, in which the localized kernel weights can be independently obtained by solving their exclusive sample-wise objectives, either linear programming (for l1-norm) or with closed-form solutions (for lp-norm). At test time, the learnt kernel weights for the training data are deployed based on the nearest-neighbor rule. Hence, to guarantee their generality among the test part, we introduce the neighborhood information and incorporate it into the empirical loss when deriving the sample-wise objectives. Extensive experiments on four benchmark machine learning datasets and two real-world computer vision datasets demonstrate the effectiveness and efficiency of the proposed algorithm.
PM-PM: PatchMatch with Potts Model for object segmentation and stereo matching.
Xu, Shibiao; Zhang, Feihu; He, Xiaofei; Shen, Xukun; Zhang, Xiaopeng
2015-07-01
This paper presents a unified variational formulation for joint object segmentation and stereo matching, which takes both accuracy and efficiency into account. In our approach, depth-map consists of compact objects, each object is represented through three different aspects: 1) the perimeter in image space; 2) the slanted object depth plane; and 3) the planar bias, which is to add an additional level of detail on top of each object plane in order to model depth variations within an object. Compared with traditional high quality solving methods in low level, we use a convex formulation of the multilabel Potts Model with PatchMatch stereo techniques to generate depth-map at each image in object level and show that accurate multiple view reconstruction can be achieved with our formulation by means of induced homography without discretization or staircasing artifacts. Our model is formulated as an energy minimization that is optimized via a fast primal-dual algorithm, which can handle several hundred object depth segments efficiently. Performance evaluations in the Middlebury benchmark data sets show that our method outperforms the traditional integer-valued disparity strategy as well as the original PatchMatch algorithm and its variants in subpixel accurate disparity estimation. The proposed algorithm is also evaluated and shown to produce consistently good results for various real-world data sets (KITTI benchmark data sets and multiview benchmark data sets).
Kjellsson, G.
1994-01-01
OCDE/GD(94)41. Er supplerende rapport til rapport: The OECD Workshop on Methods for Monitoring Organisms in the Environment, Ottawa 14-17 September 1992. Environment Monograph 90.......OCDE/GD(94)41. Er supplerende rapport til rapport: The OECD Workshop on Methods for Monitoring Organisms in the Environment, Ottawa 14-17 September 1992. Environment Monograph 90....
Ernst, Erik
2005-01-01
, where traditional invocation is optimized for as-is reuse of existing behavior. Tight coupling reduces flexibility, and traditional invocation tightly couples transfer of information and transfer of control. Method mixins decouple these two kinds of transfer, thereby opening the doors for new kinds......The world of programming has been conquered by the procedure call mechanism, including object-oriented method invocation which is a procedure call in context of an object. This paper presents an alternative, method mixin invocations, that is optimized for flexible creation of composite behavior...
Ernst, Erik
2002-01-01
invocation is optimized for as-is reuse of existing behavior. Tight coupling reduces flexibility, and traditional invocation tightly couples transfer of information and transfer of control. Method mixins decouple these two kinds of transfer, thereby opening the doors for new kinds of abstraction and reuse......The procedure call mechanism has conquered the world of programming, with object-oriented method invocation being a procedure call in context of an object. This paper presents an alternative, method mixin invocations, that is optimized for flexible creation of composite behavior, where traditional...
杨亚雄; 杨洪明; 张俊
2015-01-01
With the widespread using of electric vehicles,Electric Vehicle Aggregators (EVAs) participate in the electricity market bidding through managing geographically distributed EVAs. It can guide the charging and discharging of the electric vehicles in order and offer the opportunity of participating in the competitive electricity market.Based on the flexible bidding of EVAs,a Bi-level optimization model for participating in the electricity market was proposed in this paper. The Upper-lever model was to maximize the social benefit,the lower-lever model was to maxi-mize the charging and discharging efficiency of electric vehicles.The mixed-integer Bi-level pro-gramming formulation was transformed into an equivalent single-level mixed-integer program by the Karush-Kuhn-Tucker optimal conditions.Using the nonlinear complementary function,the multi-layer optimization model was transformed into a set of semi-smooth nonlinear algebraic equations,and the model was solved through the primal-dual interior point algorithm.Finally, the feasibility and effectiveness of the proposed model was verified by numerical simulation analy-sis.%随着电动汽车的广泛投入使用，电动汽车代理商通过代理系统中数量庞大而分散的电动汽车参与电力市场竞价，不但有利于电动汽车的有序充放电，同时也给电动汽车提供了参与电力市场竞价的机会。基于电动汽车代理商的灵活报价，提出参与电力市场竞价的双层优化模型，上层以社会效益最大化为目标，下层以电动汽车充放电效益最大化为目标；通过 KKT 条件将双层优化模型转化为单层优化模型，采用非线性互补函数将非线性不等式约束转化为等式约束，并通过原对偶内点算法求解模型；最后，通过算例仿真分析，验证了所提模型的有效性和可行性。
McLaughlin, W.L.; Miller, A.; Kovacs, A.;
2003-01-01
Chemical and physical radiation dosimetry methods, used for the measurement of absorbed dose mainly during the practical use of ionizing radiation, are discussed with respect to their characteristics and fields of application.......Chemical and physical radiation dosimetry methods, used for the measurement of absorbed dose mainly during the practical use of ionizing radiation, are discussed with respect to their characteristics and fields of application....
Dall' Anese, Emiliano; Simonetto, Andrea; Dhople, Sairaj
2016-12-01
This paper focuses on power distribution networks featuring inverter-interfaced distributed energy resources (DERs), and develops feedback controllers that drive the DER output powers to solutions of time-varying AC optimal power flow (OPF) problems. Control synthesis is grounded on primal-dual-type methods for regularized Lagrangian functions, as well as linear approximations of the AC power-flow equations. Convergence and OPF-solution-tracking capabilities are established while acknowledging: i) communication-packet losses, and ii) partial updates of control signals. The latter case is particularly relevant since it enables asynchronous operation of the controllers where DER setpoints are updated at a fast time scale based on local voltage measurements, and information on the network state is utilized if and when available, based on communication constraints. As an application, the paper considers distribution systems with high photovoltaic integration, and demonstrates that the proposed framework provides fast voltage-regulation capabilities, while enabling the near real-time pursuit of solutions of AC OPF problems.
Dall' Anese, Emiliano; Simonetto, Andrea; Dhople, Sairaj
2016-12-29
This paper focuses on power distribution networks featuring inverter-interfaced distributed energy resources (DERs), and develops feedback controllers that drive the DER output powers to solutions of time-varying AC optimal power flow (OPF) problems. Control synthesis is grounded on primal-dual-type methods for regularized Lagrangian functions, as well as linear approximations of the AC power-flow equations. Convergence and OPF-solution-tracking capabilities are established while acknowledging: i) communication-packet losses, and ii) partial updates of control signals. The latter case is particularly relevant since it enables asynchronous operation of the controllers where DER setpoints are updated at a fast time scale based on local voltage measurements, and information on the network state is utilized if and when available, based on communication constraints. As an application, the paper considers distribution systems with high photovoltaic integration, and demonstrates that the proposed framework provides fast voltage-regulation capabilities, while enabling the near real-time pursuit of solutions of AC OPF problems.
Re, Matteo; Valentini, Giorgio
2012-03-01
Ensemble methods are statistical and computational learning procedures reminiscent of the human social learning behavior of seeking several opinions before making any crucial decision. The idea of combining the opinions of different "experts" to obtain an overall “ensemble” decision is rooted in our culture at least from the classical age of ancient Greece, and it has been formalized during the Enlightenment with the Condorcet Jury Theorem[45]), which proved that the judgment of a committee is superior to those of individuals, provided the individuals have reasonable competence. Ensembles are sets of learning machines that combine in some way their decisions, or their learning algorithms, or different views of data, or other specific characteristics to obtain more reliable and more accurate predictions in supervised and unsupervised learning problems [48,116]. A simple example is represented by the majority vote ensemble, by which the decisions of different learning machines are combined, and the class that receives the majority of “votes” (i.e., the class predicted by the majority of the learning machines) is the class predicted by the overall ensemble [158]. In the literature, a plethora of terms other than ensembles has been used, such as fusion, combination, aggregation, and committee, to indicate sets of learning machines that work together to solve a machine learning problem [19,40,56,66,99,108,123], but in this chapter we maintain the term ensemble in its widest meaning, in order to include the whole range of combination methods. Nowadays, ensemble methods represent one of the main current research lines in machine learning [48,116], and the interest of the research community on ensemble methods is witnessed by conferences and workshops specifically devoted to ensembles, first of all the multiple classifier systems (MCS) conference organized by Roli, Kittler, Windeatt, and other researchers of this area [14,62,85,149,173]. Several theories have been
Szulc, Stefan
1965-01-01
Statistical Methods provides a discussion of the principles of the organization and technique of research, with emphasis on its application to the problems in social statistics. This book discusses branch statistics, which aims to develop practical ways of collecting and processing numerical data and to adapt general statistical methods to the objectives in a given field.Organized into five parts encompassing 22 chapters, this book begins with an overview of how to organize the collection of such information on individual units, primarily as accomplished by government agencies. This text then
Halberstam, Heine
2011-01-01
Derived from the techniques of analytic number theory, sieve theory employs methods from mathematical analysis to solve number-theoretical problems. This text by a noted pair of experts is regarded as the definitive work on the subject. It formulates the general sieve problem, explores the theoretical background, and illustrates significant applications.""For years to come, Sieve Methods will be vital to those seeking to work in the subject, and also to those seeking to make applications,"" noted prominent mathematician Hugh Montgomery in his review of this volume for the Bulletin of the Ameri
Shen, Jie; Wang, Li-Lian
2011-01-01
Along with finite differences and finite elements, spectral methods are one of the three main methodologies for solving partial differential equations on computers. This book provides a detailed presentation of basic spectral algorithms, as well as a systematical presentation of basic convergence theory and error analysis for spectral methods. Readers of this book will be exposed to a unified framework for designing and analyzing spectral algorithms for a variety of problems, including in particular high-order differential equations and problems in unbounded domains. The book contains a large
Freund, Rudolf J; Wilson, William J
2010-01-01
Statistical Methods, 3e provides students with a working introduction to statistical methods offering a wide range of applications that emphasize the quantitative skills useful across many academic disciplines. This text takes a classic approach emphasizing concepts and techniques for working out problems and intepreting results. The book includes research projects, real-world case studies, numerous examples and data exercises organized by level of difficulty. This text requires that a student be familiar with algebra. New to this edition: NEW expansion of exercises a
Rogers, R.
2013-01-01
In Digital Methods, Richard Rogers proposes a methodological outlook for social and cultural scholarly research on the Web that seeks to move Internet research beyond the study of online culture. It is not a toolkit for Internet research, or operating instructions for a software package; it deals wi
Glass, J.T. [North Carolina State Univ., Raleigh (United States)
1993-01-01
Methods discussed in this compilation of notes and diagrams are Raman spectroscopy, scanning electron microscopy, transmission electron microscopy, and other surface analysis techniques (auger electron spectroscopy, x-ray photoelectron spectroscopy, electron energy loss spectroscopy, and scanning tunnelling microscopy). A comparative evaluation of different techniques is performed. In-vacuo and in-situ analyses are described.
2014-01-01
A method of conducting radiofluorination of a substrate, comprising the steps of: (a) contacting an aqueous solution of [18F] fluoride with a polymer supported phosphazene base for sufficient time for trapping of [18F] fluoride on the polymer supported phosphazene base; and (b) contacting...
Lan, Yihua; Li, Cunhua; Ren, Haozheng; Zhang, Yong; Min, Zhifang
2012-10-01
A new heuristic algorithm based on the so-called geometric distance sorting technique is proposed for solving the fluence map optimization with dose-volume constraints which is one of the most essential tasks for inverse planning in IMRT. The framework of the proposed method is basically an iterative process which begins with a simple linear constrained quadratic optimization model without considering any dose-volume constraints, and then the dose constraints for the voxels violating the dose-volume constraints are gradually added into the quadratic optimization model step by step until all the dose-volume constraints are satisfied. In each iteration step, an interior point method is adopted to solve each new linear constrained quadratic programming. For choosing the proper candidate voxels for the current dose constraint adding, a so-called geometric distance defined in the transformed standard quadratic form of the fluence map optimization model was used to guide the selection of the voxels. The new geometric distance sorting technique can mostly reduce the unexpected increase of the objective function value caused inevitably by the constraint adding. It can be regarded as an upgrading to the traditional dose sorting technique. The geometry explanation for the proposed method is also given and a proposition is proved to support our heuristic idea. In addition, a smart constraint adding/deleting strategy is designed to ensure a stable iteration convergence. The new algorithm is tested on four cases including head-neck, a prostate, a lung and an oropharyngeal, and compared with the algorithm based on the traditional dose sorting technique. Experimental results showed that the proposed method is more suitable for guiding the selection of new constraints than the traditional dose sorting method, especially for the cases whose target regions are in non-convex shapes. It is a more efficient optimization technique to some extent for choosing constraints than the dose
Colquitt, Charlie W; Martin, Tonya S
2017-02-01
The prevention of pregnancy remains an important part of the practice of medicine. Contraception can occur at a number of points in the basic reproductive biological process and through a number of contraceptive product options. Pharmacists are health care providers appropriately positioned to assist patients in suitable contraceptive product selection based on their personal situations and lifestyles. This article provides an overview of available products for prevention of pregnancy and associated risks and benefits. Contraceptive products are categorized by their hormonal content and method of action. Hormonal options include oral contraceptive pills, contraceptive patch, implants, injection, intravaginal, and intrauterine devices. Barrier products prevent pregnancy by creating a physical obstacle to the successful fertilization of an egg by sperm. All products and methods are associated with benefits and potential complications that must be considered as patients, and health care providers select the most satisfactory option.
Dahlquist, Germund
2003-01-01
""Substantial, detailed and rigorous . . . readers for whom the book is intended are admirably served."" - MathSciNet (Mathematical Reviews on the Web), American Mathematical Society.Practical text strikes fine balance between students' requirements for theoretical treatment and needs of practitioners, with best methods for large- and small-scale computing. Prerequisites are minimal (calculus, linear algebra, and preferably some acquaintance with computer programming). Text includes many worked examples, problems, and an extensive bibliography.
Combining Approximation Algorithms for the Prize-Collecting TSP
Goemans, Michel X
2009-01-01
We present a 1.91457-approximation algorithm for the prize-collecting travelling salesman problem. This is obtained by combining a randomized variant of a rounding algorithm of Bienstock et al. and a primal-dual algorithm of Goemans and Williamson.
Ivanov, I.D.; de Klerk, E.
2007-01-01
In this paper we present the algorithmic framework and practical aspects of implementing a parallel version of a primal-dual semidefinite programming solver on a distributed memory computer cluster. Our implementation is based on the CSDP solver and uses a message passing interface (MPI), and the Sc
Ivanov, I.D.; de Klerk, E.
2007-01-01
In this paper we present the algorithmic framework and practical aspects of implementing a parallel version of a primal-dual semidefinite programming solver on a distributed memory computer cluster. Our implementation is based on the CSDP solver and uses a message passing interface (MPI), and the Sc
A Framework for Fast Image Deconvolution With Incomplete Observations.
Simoes, Miguel; Almeida, Luis B; Bioucas-Dias, Jose; Chanussot, Jocelyn
2016-11-01
In image deconvolution problems, the diagonalization of the underlying operators by means of the fast Fourier transform (FFT) usually yields very large speedups. When there are incomplete observations (e.g., in the case of unknown boundaries), standard deconvolution techniques normally involve non-diagonalizable operators, resulting in rather slow methods or, otherwise, use inexact convolution models, resulting in the occurrence of artifacts in the enhanced images. In this paper, we propose a new deconvolution framework for images with incomplete observations that allows us to work with diagonalized convolution operators, and therefore is very fast. We iteratively alternate the estimation of the unknown pixels and of the deconvolved image, using, e.g., an FFT-based deconvolution method. This framework is an efficient, high-quality alternative to existing methods of dealing with the image boundaries, such as edge tapering. It can be used with any fast deconvolution method. We give an example in which a state-of-the-art method that assumes periodic boundary conditions is extended, using this framework, to unknown boundary conditions. Furthermore, we propose a specific implementation of this framework, based on the alternating direction method of multipliers (ADMM). We provide a proof of convergence for the resulting algorithm, which can be seen as a "partial" ADMM, in which not all variables are dualized. We report experimental comparisons with other primal-dual methods, where the proposed one performed at the level of the state of the art. Four different kinds of applications were tested in the experiments: deconvolution, deconvolution with inpainting, superresolution, and demosaicing, all with unknown boundaries.
Petra, N.; Alexanderian, A.; Stadler, G.; Ghattas, O.
2015-12-01
We address the problem of optimal experimental design (OED) for Bayesian nonlinear inverse problems governed by partial differential equations (PDEs). The inverse problem seeks to infer a parameter field (e.g., the log permeability field in a porous medium flow model problem) from synthetic observations at a set of sensor locations and from the governing PDEs. The goal of the OED problem is to find an optimal placement of sensors so as to minimize the uncertainty in the inferred parameter field. We formulate the OED objective function by generalizing the classical A-optimal experimental design criterion using the expected value of the trace of the posterior covariance. This expected value is computed through sample averaging over the set of likely experimental data. Due to the infinite-dimensional character of the parameter field, we seek an optimization method that solves the OED problem at a cost (measured in the number of forward PDE solves) that is independent of both the parameter and the sensor dimension. To facilitate this goal, we construct a Gaussian approximation to the posterior at the maximum a posteriori probability (MAP) point, and use the resulting covariance operator to define the OED objective function. We use randomized trace estimation to compute the trace of this covariance operator. The resulting OED problem includes as constraints the system of PDEs characterizing the MAP point, and the PDEs describing the action of the covariance (of the Gaussian approximation to the posterior) to vectors. We control the sparsity of the sensor configurations using sparsifying penalty functions, and solve the resulting penalized bilevel optimization problem via an interior-point quasi-Newton method, where gradient information is computed via adjoints. We elaborate our OED method for the problem of determining the optimal sensor configuration to best infer the log permeability field in a porous medium flow problem. Numerical results show that the number of PDE
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The clinical method and the scientific method
José Arteaga Herrera
2010-12-01
Full Text Available This paper is the chapter dedicated to the scientific method and the clinical method in the authors’ Handbook “Teaching of Clinics”. Philosophycal principles of the scientific method and its stages are presented as well as the clinical method as a scientific one and its stages. A relationship between the clinical method and the medical record is established, the role of technology in the clinical method is stated and the most frequent mistakes when applying it in clinical practice are provided. Finally, the teaching of the clinical method and the appropriate settings to do it are discussed.
无
2005-01-01
An inexact Halley's method-Halley-PCG(preconditioned conjugate gradient) method is proposed for solving the systems of linear equations for improved Halley method either by Cholesky factorization exactly or by preconditioned conjugate gradient method approximately. The convergence result is given and the efficiency of the method compared to the improved Halley's method is shown.
Onose, Alexandru; Dabbech, Arwa; Wiaux, Yves
2017-07-01
Next-generation radio interferometers, like the Square Kilometre Array, will acquire large amounts of data with the goal of improving the size and sensitivity of the reconstructed images by orders of magnitude. The efficient processing of large-scale data sets is of great importance. We propose an acceleration strategy for a recently proposed primal-dual distributed algorithm. A preconditioning approach can incorporate into the algorithmic structure both the sampling density of the measured visibilities and the noise statistics. Using the sampling density information greatly accelerates the convergence speed, especially for highly non-uniform sampling patterns, while relying on the correct noise statistics optimizes the sensitivity of the reconstruction. In connection to clean, our approach can be seen as including in the same algorithmic structure both natural and uniform weighting, thereby simultaneously optimizing both the resolution and the sensitivity. The method relies on a new non-Euclidean proximity operator for the data fidelity term, that generalizes the projection on to the ℓ2 ball where the noise lives for naturally weighted data, to the projection on to a generalized ellipsoid incorporating sampling density information through uniform weighting. Importantly, this non-Euclidean modification is only an acceleration strategy to solve the convex imaging problem with data fidelity dictated only by noise statistics. We show through simulations with realistic sampling patterns the acceleration obtained using the preconditioning. We also investigate the algorithm performance for the reconstruction of the 3C129 radio galaxy from real visibilities and compare with multiscale clean, showing better sensitivity and resolution. Our matlab code is available online on GitHub.
Meshless Methods Coupled with Other Numerical Methods
Y.T.GU; G.R.LIU
2005-01-01
Meshless or mesh-free (or shorten as MFree) methods have been proposed and achieved remarkable progress over the past few years. The idea of combining MFree methods with other existing numerical techniques such as the finite element method (FEM) and the boundary element method (BEM), is naturally of great interest in many practical applications. However, the shape functions used in some MFree methods do not have the Kronecker delta function property. In order to satisfy the combined conditions of displacement compatibility, two numerical techniques, using the hybrid displacement shape function and the modified variational form, are developed and discussed in this paper. In the first technique, the original MFree shape functions are modified to the hybrid forms that possess the Kronecker delta function property. In the second technique, the displacement compatibility is satisfied via a modified variational form based on the Lagrange multiplier method. Formulations of several coupled methods are presented. Numerical examples are presented to demonstrate the effectiveness of the present coupling methods.
From Method to Post Method: A Panacea!
Masouleh, Nima Shakouri
2012-01-01
The foundation of language teaching has undergone many changes. The rise and fall of language teaching methods depends upon a variety of factors extrinsic to a method itself and often reflects the influence of profit-seekers and promoters, as well as the forces of the intellectual marketplace. There was always a source of contention among people…
The Multidimensional WKB Method.
Knudson, Stephen K.; Noid, D. W.
1989-01-01
Discusses a new method for determining the eigenvalues of the Schroedinger equation when the potential energy function does not have a simple form. Describes the mathematical methods and provides an application. Lists limitations to the method. (MVL)
ANALYSIS OF MULTISCALE METHODS
Wei-nan E; Ping-bing Ming
2004-01-01
The heterogeneous multiscale method gives a general framework for the analysis of multiscale methods. In this paper, we demonstrate this by applying this framework to two canonical problems: The elliptic problem with multiscale coefficients and the quasicontinuum method.
National Aeronautics and Space Administration — Ensemble Data Mining Methods, also known as Committee Methods or Model Combiners, are machine learning methods that leverage the power of multiple models to achieve...
Simplifications of CQC method and CCQC method
Yu Ruifang; Zhou Xiyuan
2007-01-01
The response-spectrum mode superposition method is widely used for seismic response analyses of linear systems. In using this method, the complete quadratic combination (CQC) is adopted for classically damped linear systems and the complex complete quadratic combination (CCQC) formula is adopted for non-classically damped linear systems.However, in both cases, the calculation of seismic response analyses is very time consuming. In this paper, the variation of the modal correlation coefficients of displacement, velocity and displacement-velocity with frequency and damping ratios of two modes of interest are studied, Moreover, the calculation errors generated by using CQC and square-root-of-the-sum-of-the-squares (SRSS) methods (or CCQC and CSRSS methods) for different damping combinations are compared. In these analyses,some boundary lines for classically and non-classically damped systems are plotted to distinguish the allowed minimum frequency ratio at given geometric mean of the damping ratios of both modes if their relativity is neglected. Furthermore,the simplified method, which is a special mode quadratic combination method considering only relativity of adjacent modes in CQC method and named simplified CQC or partial quadratic combination (PQC) method for classically damped linear system, is proposed to improve computational efficiency, and the criterion for determination of how many correlated modes should be adopted is proposed. Similarly, the simplified CCQC or complex partial quadratic combination (CPQC) method for the non-classically damped linear system and the corresponding criterion are also deduced. Finally, a numerical example is given to illustrate the applicability, computational accuracy and efficiency of the PQC and CPQC methods.
Simulations using meshfree methods
P, Kirana Kumara
2015-01-01
In this paper, attempt is made to solve a few problems using the Polynomial Point Collocation Method (PPCM), the Radial Point Collocation Method (RPCM), Smoothed Particle Hydrodynamics (SPH), and the Finite Point Method (FPM). A few observations on the accuracy of these methods are recorded. All the simulations in this paper are three dimensional linear elastostatic simulations, without accounting for body forces.
Numerical Methods for Multilattices
Abdulle, Assyr; Shapeev, Alexander V
2011-01-01
Among the efficient numerical methods based on atomistic models, the quasicontinuum (QC) method has attracted growing interest in recent years. The QC method was first developed for crystalline materials with Bravais lattice and was later extended to multilattices (Tadmor et al, 1999). Another existing numerical approach to modeling multilattices is homogenization. In the present paper we review the existing numerical methods for multilattices and propose another concurrent macro-to-micro method in the homogenization framework. We give a unified mathematical formulation of the new and the existing methods and show their equivalence. We then consider extensions of the proposed method to time-dependent problems and to random materials.
Chen, Junting
2011-01-01
Saddle point problems arise from many wireless applications, and primal-dual iterative algorithms are widely applied to find the saddle points. In the existing literature, the convergence results of such algorithms are established assuming the problem specific parameters remain unchanged during the iterations. However, this assumption is unrealistic in time varying wireless systems, as explicit message passing is usually involved in the iterations and the channel state information (CSI) may change in a time scale comparable to the algorithm update period. This paper investigates the convergence behavior and the tracking error of primal-dual iterative algorithms under time varying CSI. The convergence results are established by studying the stability of an equivalent virtual dynamic system derived in the paper, and the Lyapunov theory is applied for the stability analysis. We show that the average tracking error is proportional to the time variation rate of the CSI. Based on these analyses, we also derive an a...
A new algorithm for solving linear programming problems
Andrés Leonardo Ramírez Leal
2012-08-01
Full Text Available Linear programming (LP is one of the most widely-applied techniques in operations research. Many methods have been developed and several others are being proposed for solving LP problems, including the famous simplex method and interior point algorithms. This study was aimed at introducing a new method for solving LP problems. The proposed algorithm starts from an interior point and then carries out orthogonal projections using parametric straight lines to move between the interior and polyhedron frontier defining the feasible region until reaching the extreme optimal point.
任顺; 王均星; 邓念武
2012-01-01
A block element lower bound limit analysis method for the stability of arch dam abutment is presented through combining block element method with lower bound limit analysis method.By utilizing block element method to disperse calculation areas,and satisfying some conditions for the block system static field in structure surface such as Mohr-Coulomb yield conditions,stress boundary conditions and the force vector and moment balance principle in block elements,a mathematical programming model solving lower bound solution of arch dam abutment strength reserve coefficient can be constituted.The interior point algorithm is employed to solve the model.Finally,a wedge example and a test of Qinglong arch dam left abutment are researched.The calculated results obtained by block element lower bound method are compared with rigid body limit equilibrium method;it is shown that the proposed method is feasible.%将块体单元法与极限分析下限法相结合,提出了拱坝坝肩稳定的块体单元极限分析下限法.借助于块体单元法离散计算区域,通过块体系统静力场在结构面上满足Mohr-Coulomb屈服条件、应力边界条件以及在块体单元上的力矢力矩平衡原理,构成求解拱坝坝肩强度储备安全系数下限解的数学规划模型,模型的求解采用内点法.最后研究了一个楔形体算例和青龙拱坝左岸坝肩实例,通过比较块体单元下限法计算结果与刚体极限平衡法计算结果,验证了该方法的可行性.
Inflow Turbulence Generation Methods
Wu, Xiaohua
2017-01-01
Research activities on inflow turbulence generation methods have been vigorous over the past quarter century, accompanying advances in eddy-resolving computations of spatially developing turbulent flows with direct numerical simulation, large-eddy simulation (LES), and hybrid Reynolds-averaged Navier-Stokes–LES. The weak recycling method, rooted in scaling arguments on the canonical incompressible boundary layer, has been applied to supersonic boundary layer, rough surface boundary layer, and microscale urban canopy LES coupled with mesoscale numerical weather forecasting. Synthetic methods, originating from analytical approximation to homogeneous isotropic turbulence, have branched out into several robust methods, including the synthetic random Fourier method, synthetic digital filtering method, synthetic coherent eddy method, and synthetic volume forcing method. This article reviews major progress in inflow turbulence generation methods with an emphasis on fundamental ideas, key milestones, representative applications, and critical issues. Directions for future research in the field are also highlighted.
Advanced differential quadrature methods
Zong, Zhi
2009-01-01
Modern Tools to Perform Numerical DifferentiationThe original direct differential quadrature (DQ) method has been known to fail for problems with strong nonlinearity and material discontinuity as well as for problems involving singularity, irregularity, and multiple scales. But now researchers in applied mathematics, computational mechanics, and engineering have developed a range of innovative DQ-based methods to overcome these shortcomings. Advanced Differential Quadrature Methods explores new DQ methods and uses these methods to solve problems beyond the capabilities of the direct DQ method.After a basic introduction to the direct DQ method, the book presents a number of DQ methods, including complex DQ, triangular DQ, multi-scale DQ, variable order DQ, multi-domain DQ, and localized DQ. It also provides a mathematical compendium that summarizes Gauss elimination, the Runge-Kutta method, complex analysis, and more. The final chapter contains three codes written in the FORTRAN language, enabling readers to q...
Consumer Behavior Research Methods
Chrysochou, Polymeros
2017-01-01
emphasizes the discussion of primary research methods. Based on the nature of the data primary research methods are further distinguished into qualitative and quantitative. The chapter describes the most important and popular qualitative and quantitative methods. It concludes with an overall evaluation......This chapter starts by distinguishing consumer behavior research methods based on the type of data used, being either secondary or primary. Most consumer behavior research studies phenomena that require researchers to enter the field and collect data on their own, and therefore the chapter...... of the methods and how to improve quality in consumer behavior research methods....
Quality Control Analytical Methods: Method Validation.
Klang, Mark G; Williams, LaVonn A
2016-01-01
To properly determine the accuracy of a pharmaceutical product or compounded preparation, tests must be designed specifically for that evaluation. The procedures selected must be verified through a process referred to as method validation, an integral part of any good analytical practice. The results from a method validation procedure can be used to judge the quality, reliability, and consistency of analytical results. The purpose of this article is to deliver the message of the importance of validation of a pharmaceutical product or compounded preparation and to briefly discuss the results of a lack of such validation. Copyright© by International Journal of Pharmaceutical Compounding, Inc.
A New Fenchel Dual Problem in Vector Optimization
Radu Ioan Boţ; Anca Dumitru; Gert Wanka
2009-04-01
We introduce a new Fenchel dual for vector optimization problems inspired by the form of the Fenchel dual attached to the scalarized primal multiobjective problem. For the vector primal-dual pair we prove weak and strong duality. Furthermore, we recall two other Fenchel-type dual problems introduced in the past in the literature, in the vector case, and make a comparison among all three duals. Moreover, we show that their sets of maximal elements are equal.
A First Attempt on the Distributed Prize Collecting Steiner Tree Problem
Rossetti, Niccolò G., 1985-
2015-01-01
The goal of this work is to design and simulate a distributed algorithm to solve a novel variant of the Price Collecting Steiner Tree (PCST) problem, where nodes are computing entities with only local information and communication abilities. Our approach is to study existing techniques for the centralized PCST, such as the Primal-Dual Integer Program given by Goemans and Williamson (GW-algorithm), and distributed algorithms for the Minimum Spanning Tree (MST) and minimum Steiner Tree Problem....
Applied Bayesian Hierarchical Methods
Congdon, Peter D
2010-01-01
Bayesian methods facilitate the analysis of complex models and data structures. Emphasizing data applications, alternative modeling specifications, and computer implementation, this book provides a practical overview of methods for Bayesian analysis of hierarchical models.
U.S. Department of Health & Human Services — For a drug product that does not have a dissolution test method in the United States Pharmacopeia (USP), the FDA Dissolution Methods Database provides information on...
U.S. Department of Health & Human Services — For a drug product that does not have a dissolution test method in the United States Pharmacopeia (USP), the FDA Dissolution Methods Database provides information on...
Simulated floating zone method
Ozawa, Ryo; Kato, Yasuyuki; Motome, Yukitoshi
2016-01-01
This paper provides the simulated floating zone (SFZ) method that is an efficient simulation technique to obtain thermal equilibrium states, especially useful when domain formation prevents the system from reaching a spatially-uniform stable state. In the SFZ method, the system is heated up locally, and the heated region is steadily shifted, similar to the floating zone method for growing a single crystal with less lattice defect and impurity in experiments. We demonstrate that the SFZ method...
Halcomb, Elizabeth; Hickman, Louise
2015-04-08
Mixed methods research involves the use of qualitative and quantitative data in a single research project. It represents an alternative methodological approach, combining qualitative and quantitative research approaches, which enables nurse researchers to explore complex phenomena in detail. This article provides a practical overview of mixed methods research and its application in nursing, to guide the novice researcher considering a mixed methods research project.
Geobacteraceae strains and methods
Lovley, Derek R.; Nevin, Kelly P.; Yi, Hana
2015-07-07
Embodiments of the present invention provide a method of producing genetically modified strains of electricigenic microbes that are specifically adapted for the production of electrical current in microbial fuel cells, as well as strains produced by such methods and fuel cells using such strains. In preferred embodiments, the present invention provides genetically modified strains of Geobacter sulfurreducens and methods of using such strains.
A General Nonlinear Optimization Algorithm for Lower Bound Limit Analysis
Krabbenhøft, Kristian; Damkilde, Lars
2003-01-01
The non-linear programming problem associated with the discrete lower bound limit analysis problem is treated by means of an algorithm where the need to linearize the yield criteria is avoided. The algorithm is an interior point method and is completely general in the sense that no particular...... finite element discretization or yield criterion is required. As with interior point methods for linear programming the number of iterations is affected only little by the problem size. Some practical implementation issues are discussed with reference to the special structure of the common lower bound...
Numerical methods using Matlab
Gupta, Abhishek
2015-01-01
Numerical Methods with MATLAB provides a highly-practical reference work to assist anyone working with numerical methods. A wide range of techniques are introduced, their merits discussed and fully working MATLAB code samples supplied to demonstrate how they can be coded and applied. Numerical methods have wide applicability across many scientific, mathematical, and engineering disciplines and are most often employed in situations where working out an exact answer to the problem by another method is impractical. Numerical Methods with MATLAB presents each topic in a concise and readable
The Generalized Sturmian Method
Avery, James Emil
2011-01-01
generations of researchers were left to work out how to achieve this ambitious goal for molecular systems of ever-increasing size. This book focuses on non-mainstream methods to solve the molecular electronic Schrödinger equation. Each method is based on a set of core ideas and this volume aims to explain...... these ideas clearly so that they become more accessible. By bringing together these non-standard methods, the book intends to inspire graduate students, postdoctoral researchers and academics to think of novel approaches. Is there a method out there that we have not thought of yet? Can we design a new method...
Mimetic discretization methods
Castillo, Jose E
2013-01-01
To help solve physical and engineering problems, mimetic or compatible algebraic discretization methods employ discrete constructs to mimic the continuous identities and theorems found in vector calculus. Mimetic Discretization Methods focuses on the recent mimetic discretization method co-developed by the first author. Based on the Castillo-Grone operators, this simple mimetic discretization method is invariably valid for spatial dimensions no greater than three. The book also presents a numerical method for obtaining corresponding discrete operators that mimic the continuum differential and
Genetic Algorithm Based Immigrants for Dynamic Travelling Salesman Problem%基于移民策略求解动态TSP问题的遗传算法
付兴武; 张剑光
2011-01-01
在标准遗传算法(SGA)中加入移民策略可以丰富种群多样性,使SGA能够更好的适应环境的变化.为了改善基于移民策略的遗传算法在搜索空间内的探索能力,受原对偶映射思想的启发,设计了基于原对偶映射的移民策略(Primal-Dual based Immigrants,PDI),并将这种策略加入到遗传算法中,求解动态旅行商问题(Dynamic Travelling Salesman Problem,DTSP).仿真结果表明,与基于其他移民策略的遗传算法相比,PDIGA能够更好的适应环境的变化.%Add immigrants in the standard genetic algorithm can enrich the population diversity, so that SGA can better adapt to environment changes. In order to improve the space exploration search capabilities of genetic algorithm based on immigrants, inspired by primal-dual, designed Primal-Dual based Immigrants(PDI), and add PDI to SGA to solve the Dynamic Travelling Salesman Problem(DTSP). Simulation results show that PDIGA is better able to adapt to environment changes to other genetic algorithms based on immigrants.
Methods for assessing geodiversity
Zwoliński, Zbigniew; Najwer, Alicja; Giardino, Marco
2017-04-01
The accepted systematics of geodiversity assessment methods will be presented in three categories: qualitative, quantitative and qualitative-quantitative. Qualitative methods are usually descriptive methods that are suited to nominal and ordinal data. Quantitative methods use a different set of parameters and indicators to determine the characteristics of geodiversity in the area being researched. Qualitative-quantitative methods are a good combination of the collection of quantitative data (i.e. digital) and cause-effect data (i.e. relational and explanatory). It seems that at the current stage of the development of geodiversity research methods, qualitative-quantitative methods are the most advanced and best assess the geodiversity of the study area. Their particular advantage is the integration of data from different sources and with different substantive content. Among the distinguishing features of the quantitative and qualitative-quantitative methods for assessing geodiversity are their wide use within geographic information systems, both at the stage of data collection and data integration, as well as numerical processing and their presentation. The unresolved problem for these methods, however, is the possibility of their validation. It seems that currently the best method of validation is direct filed confrontation. Looking to the next few years, the development of qualitative-quantitative methods connected with cognitive issues should be expected, oriented towards ontology and the Semantic Web.
Jensen, Torben Elgaard; Andreasen, Mogens Myrup
2010-01-01
The paper challenges the dominant and widespread view that a good design method will guarantee a systematic approach as well as certain results. First, it explores the substantial differences between on the one hand the conception of methods implied in Pahl & Beitz’s widely recognized text book...... subject to change; The goals of methods are less stable than assumed. The paper finally suggests that ethnomethodology and similar approaches direct our attention to the fact that method use is always a situated and socially interactive affair. It is crucial to attend to these dimensions of method use...... on engineering design, and on the other hand the understanding of method use, which has emerged from micro-sociological studies of practice (ethnomethodology). Second, it reviews a number of case studies conducted by engineering students, who were instructed to investigate the actual use of design methods...
Consensus theoretic classification methods
Benediktsson, Jon A.; Swain, Philip H.
1992-01-01
Consensus theory is adopted as a means of classifying geographic data from multiple sources. The foundations and usefulness of different consensus theoretic methods are discussed in conjunction with pattern recognition. Weight selections for different data sources are considered and modeling of non-Gaussian data is investigated. The application of consensus theory in pattern recognition is tested on two data sets: 1) multisource remote sensing and geographic data and 2) very-high-dimensional remote sensing data. The results obtained using consensus theoretic methods are found to compare favorably with those obtained using well-known pattern recognition methods. The consensus theoretic methods can be applied in cases where the Gaussian maximum likelihood method cannot. Also, the consensus theoretic methods are computationally less demanding than the Gaussian maximum likelihood method and provide a means for weighting data sources differently.
Methods of Software Verification
R. E. Gurin
2015-01-01
Full Text Available This article is devoted to the problem of software verification (SW. Methods of software verification designed to check the software for compliance with the stated requirements such as correctness, system security and system adaptability to small changes in the environment, portability and compatibility, etc. These are various methods both by the operation process and by the way of achieving result. The article describes the static and dynamic methods of software verification and paid attention to the method of symbolic execution. In its review of static analysis are discussed and described the deductive method, and methods for testing the model. A relevant issue of the pros and cons of a particular method is emphasized. The article considers classification of test techniques for each method. In this paper we present and analyze the characteristics and mechanisms of the static analysis of dependencies, as well as their views, which can reduce the number of false positives in situations where the current state of the program combines two or more states obtained both in different paths of execution and in working with multiple object values. Dependences connect various types of software objects: single variables, the elements of composite variables (structure fields, array elements, the size of the heap areas, the length of lines, the number of initialized array elements in the verification code using static methods. The article pays attention to the identification of dependencies within the framework of the abstract interpretation, as well as gives an overview and analysis of the inference tools.Methods of dynamic analysis such as testing, monitoring and profiling are presented and analyzed. Also some kinds of tools are considered which can be applied to the software when using the methods of dynamic analysis. Based on the work a conclusion is drawn, which describes the most relevant problems of analysis techniques, methods of their solutions and
A semidefinite programming approach for solving Multiobjective Linear Programming
Blanco, Víctor; Ben-Ali, Safae El-Haj
2011-01-01
Several algorithms are available in the literature for finding the entire set of Pareto-optimal solutions in MultiObjective Linear Programming (MOLP). However, it has not been proposed so far an interior point algorithm that finds all Pareto-optimal solutions of MOLP. We present an explicit construction, based on a transformation of any MOLP into a finite sequence of SemiDefinite Programs (SDP), the solutions of which give the entire set of Pareto-optimal extreme points solutions of MOLP. These SDP problems are solved by interior point methods; thus our approach provides a pseudo-polynomial interior point methodology to find the set of Pareto-optimal solutions of MOLP.
Svabo, Connie
2016-01-01
A performative schizoid method is developed as a method contribution to performance as research. The method is inspired by contemporary research in the human and social sciences urging experimentation and researcher engagement with creative and artistic practice. In the article, the method...... is presented and an example is provided of a first exploratory engagement with it. The method is used in a specific project Becoming Iris, making inquiry into arts-based knowledge creation during a three month visiting scholarship at a small, independent visual art academy. Using the performative schizoid...... method in Becoming Iris results in four audio-visual and performance-based productions, centered on an emergent theme of the scholartist as a bird in borrowed feathers. Interestingly, the moral lesson of the fable about the vain jackdaw, who dresses in borrowed peacock feathers and becomes a castout...
Wright, Jason T
2012-01-01
This chapter reviews various methods of detecting planetary companions to stars from an observational perspective, focusing on radial velocities, astrometry, direct imaging, transits, and gravitational microlensing. For each method, this chapter first derives or summarizes the basic observable phenomena that are used to infer the ex- istence of planetary companions, as well as the physical properties of the planets and host stars that can be derived from the measurement of these signals. This chapter then outlines the general experimental requirements to robustly detect the signals us- ing each method, by comparing their magnitude to the typical sources of measurement uncertainty. This chapter goes on to compare the various methods to each other by outlining the regions of planet and host star parameter space where each method is most sensitive, stressing the complementarity of the ensemble of the methods at our disposal. Finally, there is a brief review of the history of the young exoplanet field, from the f...
Phenomenographic Research Method
Erdem ÇEKMEZ
2012-12-01
Full Text Available Phenomenography, an approach to educational research, emerged from the studies carried out by Ference Marton and his colleagues at the University of Göteborg, Sweden, in the early 1970s. Phenomenography is the empirical study of the different ways in which people experience, perceive, apprehend, understand, conceptualize various phenomena in the world around them. Not only this method has been used much in educational researches in Turkey, but also the books about research methods do not provide detailed information about this method in details. This study explains the aim, characteristics, historical background and how to ensure the generalization, validity and reliability of phenomenographic research outcomes, besides mentions to the studies in which phenomenographic research method was used. In addition, the differences and similarities between this method and methods similar to phenomenology are explained.
The Schwinger Variational Method
Huo, Winifred M.
1995-01-01
Variational methods have proven invaluable in theoretical physics and chemistry, both for bound state problems and for the study of collision phenomena. For collisional problems they can be grouped into two types: those based on the Schroedinger equation and those based on the Lippmann-Schwinger equation. The application of the Schwinger variational (SV) method to e-molecule collisions and photoionization has been reviewed previously. The present chapter discusses the implementation of the SV method as applied to e-molecule collisions.
Hageman, Louis A
2004-01-01
This graduate-level text examines the practical use of iterative methods in solving large, sparse systems of linear algebraic equations and in resolving multidimensional boundary-value problems. Assuming minimal mathematical background, it profiles the relative merits of several general iterative procedures. Topics include polynomial acceleration of basic iterative methods, Chebyshev and conjugate gradient acceleration procedures applicable to partitioning the linear system into a "red/black" block form, adaptive computational algorithms for the successive overrelaxation (SOR) method, and comp
Well testing: interpretation methods
Bourdarot, G. [Elf Aquitaine, 92 - Courbevoie (France)
1998-12-31
This book presents the different methods to use for interpreting well tests: conventional methods, type curves, derivative, according to the type of reservoir limits (faults, channels, secant faults, constant pressure limits, closed reservoir) and the well configuration (partial penetration, inclined, fractured, horizontal or injection well). It indicates the method to be used in the case of more complex reservoirs (fissured reservoirs, two-layered reservoirs), interference tests or pulse tests and when fluid produced is gas or polyphasic. (authors) 60 refs.
Well testing: interpretation methods
Bourdarot, G. (Elf Aquitaine, 92 - Courbevoie (France))
1998-01-01
This book presents the different methods to use for interpreting well tests: conventional methods, type curves, derivative, according to the type of reservoir limits (faults, channels, secant faults, constant pressure limits, closed reservoir) and the well configuration (partial penetration, inclined, fractured, horizontal or injection well). It indicates the method to be used in the case of more complex reservoirs (fissured reservoirs, two-layered reservoirs), interference tests or pulse tests and when fluid produced is gas or polyphasic. (authors) 60 refs.
Nielsen, Peter Vilhelm
The velocity level in a room ventilated by jet ventilation is strongly influenced by the supply conditions. The momentum flow in the supply jets controls the air movement in the room and, therefore, it is very important that the inlet conditions and the numerical method can generate a satisfactor...... description of this momentum flow. The Box Method is a practical method for the description of an Air Terminal Device which will save grid points and ensure the right level of the momentum flow....
THE ALGORITHM OF MESHFREE METHOD OF RADIAL BASIS FUNCTIONS IN TASKS OF UNDERGROUND HYDROMECHANICS
N. V. Medvid
2016-01-01
Full Text Available A Mathematical model of filtering consolidation in the body of soil dam with conduit andwashout zone in two-dimensional case is considered. The impact of such technogenic factors as temperature, salt concentration, subsidence of upper boundary and interior points of the dam with time is taken into account. The software to automate the calculation of numerical solution of the boundary problem by radial basis functions has been created, which enables to conduct numerical experiments by varying the input parameters and shape. The influence of the presence of conduit and washout zone on the pressure, temperature and concentration of salts in the dam body at different time intervals isinvestigated. A number of numerical experiments is conducted and the analysis of dam accidents is performed.
具有可信度分析的卷烟质量评估模型预测控制方法%Predictive Control Method with Credibility in Cigarette Sensory Evaluation
曾建新; 宫会丽; 石硕; 杨宁
2013-01-01
为了改善大多数已建模型在预测时出现盲目的、机械的预测错误情况，以不同产地烤烟和白肋烟数据作为实验样本，综合集成假设检验、凸壳构造与内点分析、序列随机性检验等理论和方法，在预测控制环节设计了具有拒绝识别和可信度分析特征的分类器预测控制算法。实验结果表明，分类器能有效地接受与训练数据相似的测试样本，并给出凸壳内点测试样本的预测值和可信度参考值，同时亦能准确拒绝识别与烤烟质量数据差异较大的白肋烟和特异香型烤烟样本。不同类型测试数据实验验证了该算法的可行性和有效性，尤其是对于以专家经验或领域知识为主的卷烟质量评价问题更加实用。%In order to improve mechanical and blind prediction behavior of some built models, a classifier prediction control algorithm was designed with flue-cured tobacco and burley tobacco in different producing areas as experimental samples. It had the characteristic of rejecting recognition and credibility analysis through integrating several theories and methods including hypothesis testing, convex hull, interior point analysis and sequence random testing. The results demonstrated that classifier could effectively accept test sample set and give predictive values and reliability reference values of test data in convex hull. In the meanwhile, classifier could also accurately reject burley tobacco sample and special type flue-cured sample, which was different from flue-cured sample set. The feasibility and validity of classifier were verified through different type of testing data, especially the practicality of cigarette sensory evaluation was based on expert experience or domain knowledge.
Lindley, C; Mackowiak, J
1985-01-01
Various methods for controlling inventory are described, and the advantages and disadvantages of each are discussed. The open-to-buy (OTB) budget method limits purchases to a specific amount of funds available for purchasing pharmaceuticals during a specified period. The emphasis of the OTB method is financial control of the pharmacy inventory. Although it is useful in monitoring and adjusting the dollar value of the inventory, it should be combined with other methods for a total inventory control system. The primary emphasis of the short-list method is to provide accurate and timely inventory information to the person responsible for order placement. The short list identifies the items that are in short supply. It is the most common feedback and control mechanism in use, but it is best suited for settings where duplicate or reserve stock is maintained and monitored by more rigorous methods. The main objective of the minimum and maximum method is to determine when and how much to order of each item. It also provides limited dollar control. The major disadvantage of this method is the time it requires to establish the minimum and maximum levels and to update them regularly to reflect changes in demand. The stock record card method is used to record information on the movement of goods in and out of the storage area. Stock cards can also be used to monitor inventory levels and facilitate order initiation. It is probably the optimum method to be used alone. The most effective system of inventory control is one employing a combination of these methods tailored to meet the institution's needs and available resources.
Methods for data classification
Garrity, George; Lilburn, Timothy G.
2011-10-11
The present invention provides methods for classifying data and uncovering and correcting annotation errors. In particular, the present invention provides a self-organizing, self-correcting algorithm for use in classifying data. Additionally, the present invention provides a method for classifying biological taxa.
BOUCHER, JOHN G.
THE AUTHOR STATES THAT BEFORE PRESENT FOREIGN LANGUAGE TEACHING METHODS CAN BE DISCUSSED INTELLIGENTLY, THE RESEARCH IN PSYCHOLOGY AND LINGUISTICS WHICH HAS INFLUENCED THE DEVELOPMENT OF THESE METHODS MUST BE CONSIDERED. MANY FOREIGN LANGUAGE TEACHERS WERE BEGINNING TO FEEL COMFORTABLE WITH THE AUDIOLINGUAL APPROACH WHEN NOAM CHOMSKY, IN HIS 1966…
Diamond, J. M.
1965-01-01
A noise-measuring method based on the use of a calibrated noise generator and an output meter with a special scale is described. The method eliminates the effect of noise contributions occurring in the circuits following the device under test....
Method of forming nanodielectrics
Tuncer, Enis [Knoxville, TN; Polyzos, Georgios [Oak Ridge, TN
2014-01-07
A method of making a nanoparticle filled dielectric material. The method includes mixing nanoparticle precursors with a polymer material and reacting the nanoparticle mixed with the polymer material to form nanoparticles dispersed within the polymer material to form a dielectric composite.
Soybean allergen detection methods
Pedersen, Mona H; Holzhauser, Thomas; Bisson, Caroline
2008-01-01
Soybean containing products are widely consumed, thus reliable methods for detection of soy in foods are needed in order to make appropriate risk assessment studies to adequately protect soy allergic patients. Six methods were compared using eight food products with a declared content of soy...
Del Grande, John
1993-01-01
Describes the method that Archimedes utilized to calculate the volumes of spheres and other solids. The method found the volume of a sphere by comparing the mass of parallel slices of a sphere and a cone with that of a cylinder of known mass. (MDH)
Check, Joseph; Schutt, Russell K.
2011-01-01
"Research Methods in Education" introduces research methods as an integrated set of techniques for investigating questions about the educational world. This lively, innovative text helps students connect technique and substance, appreciate the value of both qualitative and quantitative methodologies, and make ethical research decisions.…
2010-01-01
The present invention relates to a method for making Cheddar type and Continental type cheese with an adjunct culture comprising a Lactobacillus helveticus strain.......The present invention relates to a method for making Cheddar type and Continental type cheese with an adjunct culture comprising a Lactobacillus helveticus strain....
Improved nonlinear prediction method
Adenan, Nur Hamiza; Md Noorani, Mohd Salmi
2014-06-01
The analysis and prediction of time series data have been addressed by researchers. Many techniques have been developed to be applied in various areas, such as weather forecasting, financial markets and hydrological phenomena involving data that are contaminated by noise. Therefore, various techniques to improve the method have been introduced to analyze and predict time series data. In respect of the importance of analysis and the accuracy of the prediction result, a study was undertaken to test the effectiveness of the improved nonlinear prediction method for data that contain noise. The improved nonlinear prediction method involves the formation of composite serial data based on the successive differences of the time series. Then, the phase space reconstruction was performed on the composite data (one-dimensional) to reconstruct a number of space dimensions. Finally the local linear approximation method was employed to make a prediction based on the phase space. This improved method was tested with data series Logistics that contain 0%, 5%, 10%, 20% and 30% of noise. The results show that by using the improved method, the predictions were found to be in close agreement with the observed ones. The correlation coefficient was close to one when the improved method was applied on data with up to 10% noise. Thus, an improvement to analyze data with noise without involving any noise reduction method was introduced to predict the time series data.
Chainer, Timothy J.; Dang, Hien P.; Parida, Pritish R.; Schultz, Mark D.; Sharma, Arun
2015-08-11
A method aspect for removing heat from a data center may use liquid coolant cooled without vapor compression refrigeration on a liquid cooled information technology equipment rack. The method may also include regulating liquid coolant flow to the data center through a range of liquid coolant flow values with a controller-apparatus based upon information technology equipment temperature threshold of the data center.
D.R. Gasper (Des)
2003-01-01
textabstractINVESTIGATING IDEAS, IDEOLOGIES AND PRACTICES This paper presents some methods for trying to make sense of international aid and of its study.1 Some of the methods may be deemed ethnographic; the others are important partners to them, but rather different. In the course of discussing q
Check, Joseph; Schutt, Russell K.
2011-01-01
"Research Methods in Education" introduces research methods as an integrated set of techniques for investigating questions about the educational world. This lively, innovative text helps students connect technique and substance, appreciate the value of both qualitative and quantitative methodologies, and make ethical research decisions.…
METHODS OF MAGNETOTELLURIC ANALYSIS
Magnetotelluric prospecting is a method of geophysical exploration that makes use of the fluctuations in the natural electric and magnetic fields...function of the conductivity structure of the earth’s substrata. This report describes some new methods for analyzing and interpreting magnetotelluric
Nölting, Bengt
2006-01-01
Incorporating recent dramatic advances, this textbook presents a fresh and timely introduction to modern biophysical methods. An array of new, faster and higher-power biophysical methods now enables scientists to examine the mysteries of life at a molecular level. This innovative text surveys and explains the ten key biophysical methods, including those related to biophysical nanotechnology, scanning probe microscopy, X-ray crystallography, ion mobility spectrometry, mass spectrometry, proteomics, and protein folding and structure. Incorporating much information previously unavailable in tutorial form, Nölting employs worked examples and 267 illustrations to fully detail the techniques and their underlying mechanisms. Methods in Modern Biophysics is written for advanced undergraduate and graduate students, postdocs, researchers, lecturers and professors in biophysics, biochemistry and related fields. Special features in the 2nd edition: • Illustrates the high-resolution methods for ultrashort-living protei...
Saucez, Ph
2001-01-01
The general Method of Lines (MOL) procedure provides a flexible format for the solution of all the major classes of partial differential equations (PDEs) and is particularly well suited to evolutionary, nonlinear wave PDEs. Despite its utility, however, there are relatively few texts that explore it at a more advanced level and reflect the method''s current state of development.Written by distinguished researchers in the field, Adaptive Method of Lines reflects the diversity of techniques and applications related to the MOL. Most of its chapters focus on a particular application but also provide a discussion of underlying philosophy and technique. Particular attention is paid to the concept of both temporal and spatial adaptivity in solving time-dependent PDEs. Many important ideas and methods are introduced, including moving grids and grid refinement, static and dynamic gridding, the equidistribution principle and the concept of a monitor function, the minimization of a functional, and the moving finite elem...
Fast Distributed Gradient Methods
Jakovetic, Dusan; Moura, Jose M F
2011-01-01
The paper proposes new fast distributed optimization gradient methods and proves convergence to the exact solution at rate O(\\log k/k), much faster than existing distributed optimization (sub)gradient methods with convergence O(1/\\sqrt{k}), while incurring practically no additional communication nor computation cost overhead per iteration. We achieve this for convex (with at least one strongly convex,) coercive, three times differentiable and with Lipschitz continuous first derivative (private) cost functions. Our work recovers for distributed optimization similar convergence rate gains obtained by centralized Nesterov gradient and fast iterative shrinkage-thresholding algorithm (FISTA) methods over ordinary centralized gradient methods. We also present a constant step size distributed fast gradient algorithm for composite non-differentiable costs. A simulation illustrates the effectiveness of our distributed methods.
Cooperative method development
Dittrich, Yvonne; Rönkkö, Kari; Eriksson, Jeanette;
2008-01-01
research is not easily combined with the improvement orientation of an engineering discipline. During the last 6 years, we have applied an approach we call `cooperative method development', which combines qualitative social science fieldwork, with problem-oriented method, technique and process improvement....... The action research based approach focusing on shop floor software development practices allows an understanding of how contextual contingencies influence the deployment and applicability of methods, processes and techniques. This article summarizes the experiences and discusses the further development......The development of methods tools and process improvements is best to be based on the understanding of the development practice to be supported. Qualitative research has been proposed as a method for understanding the social and cooperative aspects of software development. However, qualitative...
Jensen, Martin Trandberg
2014-01-01
This chapter showcases how mobile methods are more than calibrated techniques awaiting application by tourism researchers, but productive in the enactment of the mobile (Law and Urry, 2004). Drawing upon recent findings deriving from a PhD course on mobility and mobile methods it reveals...... the conceptual ambiguousness of the term ‘mobile methods’. In order to explore this ambiguousness the chapter provides a number of examples deriving from tourism research, to explore how mobile methods are always entangled in ideologies, predispositions, conventions and practice-realities. Accordingly......, the engagements with methods are acknowledged to be always political and contextual, reminding us to avoid essentialist discussions regarding research methods. Finally, the chapter draws on recent fieldwork to extend developments in mobilities-oriented tourism research, by employing auto-ethnography to call...
D. Sümeyra Demirkıran
2014-03-01
Full Text Available Concept of age estimation plays an important role on both civil law and regulation of criminal behaviors. In forensic medicine, age estimation is practiced for individual requests as well for request of the court. In this study it is aimed to compile the methods of age estimation and to make recommendations for the solution of the problems encountered. In radiological method the epiphyseal lines of the bones and views of the teeth are used. In order to estimate the age by comparing bone radiographs; Greulich-Pyle Atlas (GPA, Tanner-Whitehouse Atlas (TWA and “Adli Tıpta Yaş Tayini (ATYT” books are used. Bone age is found to be 2 years older averagely than chronologic age, especially in puberty, according to the forensic age estimations described in the ATYT book. For the age estimation with teeth, Demirjian method is used. In time different methods are developed by modifying Demirjian method. However no accurate method was found. Histopathological studies are done on bone marrow cellularity and dermis cells. No correlation was found between histopathoogical findings and choronologic age. Important ethical and legal issues are brought with current age estimation methods especially in teenage period. Therefore it is required to prepare atlases of bone age compatible with our society by collecting the findings of the studies in Turkey. Another recommendation could be to pay attention to the courts of age raising trials of teenage women and give special emphasis on birth and population records
STATISTICAL METHODS IN HISTORY
Orlov A. I.
2016-01-01
Full Text Available We have given a critical analysis of statistical models and methods for processing text information in historical records to establish the times when there were certain events, ie, to build science-based chronology. There are three main kinds of sources of knowledge of ancient history: ancient texts, the remains of material culture and traditions. The specific date of the extracted by archaeologists objects in most cases can not be found. The group of Academician A.T. Fomenko has developed and applied new statistical methods for analysis of historical texts (Chronicle, based on the intensive use of computer technology. Two major scientific results were: the majority of historical records that we know now, are duplicated (in particular, chronicles, describing the so-called "Ancient Rome" and "Middle Ages", talking about the same events; the known historical chronicles tell us about real events, separated from the present time for not more than 1000 years. It was found that chronicles describing the history of "ancient times" and "Middle Ages" and the chronicle of Chinese history and the history of various European countries do not talk about different, but about the same events. We have the attempt of a new dating of historical events and restoring the true history of human society based on new data. From the standpoint of statistical methods of historical records and images of their fragments – they are special cases of non-numeric objects of nature. Therefore, developed by the group of A.T. Fomenko computer-statistical methods are the part of non-numerical statistics. We have considered some methods of statistical analysis of chronicles applied by the group of A.T. Fomenko: correlation method of maximums; dynasties method; the method of attenuation frequency; questionnaire method codes. New chronology allows us to understand much of the battle of ideas in modern science and mass consciousness. It becomes clear the root cause of cautious
Conic convex programming and self-dual embedding
Z-Q. Luo; J.F. Sturm; S. Zhang (Shuzhong)
1998-01-01
textabstractHow to initialize an algorithm to solve an optimization problem is of great theoretical and practical importance. In the simplex method for linear programming this issue is resolved by either the two-phase approach or using the so-called big M technique. In the interior point method, the
The Prescribed Velocity Method
Nielsen, Peter Vilhelm
The- velocity level in a room ventilated by jet ventilation is strongly influenced by the supply conditions. The momentum flow in the supply jets controls the air movement in the room and, therefore, it is very important that the inlet conditions and the numerical method can generate a satisfactory...... description of this momentum flow. The Prescribed Velocity Method is a practical method for the description of an Air Terminal Device which will save grid points close to the opening and ensure the right level of the momentum flow....
Lynnerup, Niels
2009-01-01
Mummies are human remains with preservation of non-bony tissue. Many mummy studies focus on the development and application of non-destructive methods for examining mummies, including radiography, CT-scanning with advanced 3-dimensional visualisations, and endoscopic techniques, as well as minima......Mummies are human remains with preservation of non-bony tissue. Many mummy studies focus on the development and application of non-destructive methods for examining mummies, including radiography, CT-scanning with advanced 3-dimensional visualisations, and endoscopic techniques, as well...... as minimally-destructive chemical, physical and biological methods for, e.g., stable isotopes, trace metals and DNA....
Mittemeijer, E J
2013-01-01
The role of diffraction methods for the solid-state sciences has been pivotal to determining the (micro)structure of a material. Particularly, the expanding activities in materials science have led to the development of new methods for analysis by diffraction. This book offers an authoritative overview of the new developments in the field of analysis of matter by (in particular X-ray, electron and neutron) diffraction. It is composed of chapters written by leading experts on 'modern diffraction methods'. The focus in the various chapters of this book is on the current forefront of research on
Jayaraman, Arul
2009-01-01
This volume provides a detailed look at the two main aspects of systems biology: the design of sophisticated experimental methods and the development of complex models to analyze the data. Focusing on methods that are being used to solve current problems in biomedical science and engineering, this comprehensive, richly illustrated resource shows you how to design of state-of-the art methods for analyzing biological systems, implement experimental approaches for investigating cellular behavior in health and disease, use algorithms and modeling techniques for quantitatively describing biomedical
Athanasios Drigas
2016-03-01
Full Text Available This article bridges the gap between the Montessori Method and Information and Communication Technologies (ICTs in contemporary education. It reviews recent research works which recall the Montessori philosophy, principles and didactical tools applying to today’s computers and supporting technologies in children’s learning process. This article reviews how important the stimulation of human senses in the learning process is, as well as the development of Montessori materials using the body and the hand in particular, all according to the Montessori Method along with recent researches over ICTs. Montessori Method within information society age acquires new perspectives, new functionality and new efficacy.
Numerical methods using Matlab
Lindfield, George
2012-01-01
Numerical Methods using MATLAB, 3e, is an extensive reference offering hundreds of useful and important numerical algorithms that can be implemented into MATLAB for a graphical interpretation to help researchers analyze a particular outcome. Many worked examples are given together with exercises and solutions to illustrate how numerical methods can be used to study problems that have applications in the biosciences, chaos, optimization, engineering and science across the board. Numerical Methods using MATLAB, 3e, is an extensive reference offering hundreds of use
Raj, Rishi; Cologna, Marco; Francis, John S.
2016-05-10
This disclosure provides methods of flash sintering and compositions created by these methods. Methods for sintering multilayered bodies are provided in which a sintered body is produced in less than one minute. In one aspect, each layer is of a different composition, and may be constituted wholly from a ceramic or from a combination of ceramic and metallic particles. When the body includes a layer of an anode composition, a layer of an electrolyte composition and a layer of a cathode composition, the sintered body can be used to produce a solid oxide fuel cell.
Structural Reliability Methods
Ditlevsen, Ove Dalager; Madsen, H. O.
of structural reliability, including the theoretical basis for these methods. Partial safety factor codes under current practice are briefly introduced and discussed. A probabilistic code format for obtaining a formal reliability evaluation system that catches the most essential features of the nature......The structural reliability methods quantitatively treat the uncertainty of predicting the behaviour and properties of a structure given the uncertain properties of its geometry, materials, and the actions it is supposed to withstand. This book addresses the probabilistic methods for evaluation...
Generalized subspace correction methods
Kolm, P. [Royal Institute of Technology, Stockholm (Sweden); Arbenz, P.; Gander, W. [Eidgenoessiche Technische Hochschule, Zuerich (Switzerland)
1996-12-31
A fundamental problem in scientific computing is the solution of large sparse systems of linear equations. Often these systems arise from the discretization of differential equations by finite difference, finite volume or finite element methods. Iterative methods exploiting these sparse structures have proven to be very effective on conventional computers for a wide area of applications. Due to the rapid development and increasing demand for the large computing powers of parallel computers, it has become important to design iterative methods specialized for these new architectures.
Oza, Nikunj C.
2004-01-01
Ensemble Data Mining Methods, also known as Committee Methods or Model Combiners, are machine learning methods that leverage the power of multiple models to achieve better prediction accuracy than any of the individual models could on their own. The basic goal when designing an ensemble is the same as when establishing a committee of people: each member of the committee should be as competent as possible, but the members should be complementary to one another. If the members are not complementary, Le., if they always agree, then the committee is unnecessary---any one member is sufficient. If the members are complementary, then when one or a few members make an error, the probability is high that the remaining members can correct this error. Research in ensemble methods has largely revolved around designing ensembles consisting of competent yet complementary models.
Adaptive Algebraic Multigrid Methods
Brezina, M; Falgout, R; MacLachlan, S; Manteuffel, T; McCormick, S; Ruge, J
2004-04-09
Our ability to simulate physical processes numerically is constrained by our ability to solve the resulting linear systems, prompting substantial research into the development of multiscale iterative methods capable of solving these linear systems with an optimal amount of effort. Overcoming the limitations of geometric multigrid methods to simple geometries and differential equations, algebraic multigrid methods construct the multigrid hierarchy based only on the given matrix. While this allows for efficient black-box solution of the linear systems associated with discretizations of many elliptic differential equations, it also results in a lack of robustness due to assumptions made on the near-null spaces of these matrices. This paper introduces an extension to algebraic multigrid methods that removes the need to make such assumptions by utilizing an adaptive process. The principles which guide the adaptivity are highlighted, as well as their application to algebraic multigrid solution of certain symmetric positive-definite linear systems.
Methods for cellobiosan utilization
Linger, Jeffrey; Beckham, Gregg T.
2017-07-11
Disclosed herein are enzymes useful for the degradation of cellobiosan in materials such a pyrolysis oils. Methods of degrading cellobiosan using enzymes or organisms expressing the same are also disclosed.
Compressive Spectral Renormalization Method
Bayindir, Cihan
2016-01-01
In this paper a novel numerical scheme for finding the sparse self-localized states of a nonlinear system of equations with missing spectral data is introduced. As in the Petviashivili's and the spectral renormalization method, the governing equation is transformed into Fourier domain, but the iterations are performed for far fewer number of spectral components (M) than classical versions of the these methods with higher number of spectral components (N). After the converge criteria is achieved for M components, N component signal is reconstructed from M components by using the l1 minimization technique of the compressive sampling. This method can be named as compressive spectral renormalization (CSRM) method. The main advantage of the CSRM is that, it is capable of finding the sparse self-localized states of the evolution equation(s) with many spectral data missing.
Iii. Sleep assessment methods.
Sadeh, Avi
2015-03-01
Sleep is a complex phenomenon that could be understood and assessed at many levels. Sleep could be described at the behavioral level (relative lack of movements and awareness and responsiveness) and at the brain level (based on EEG activity). Sleep could be characterized by its duration, by its distribution during the 24-hr day period, and by its quality (e.g., consolidated versus fragmented). Different methods have been developed to assess various aspects of sleep. This chapter covers the most established and common methods used to assess sleep in infants and children. These methods include polysomnography, videosomnography, actigraphy, direct observations, sleep diaries, and questionnaires. The advantages and disadvantages of each method are highlighted.
Stochastic optimization methods
Marti, Kurt
2005-01-01
Optimization problems arising in practice involve random parameters. For the computation of robust optimal solutions, i.e., optimal solutions being insensitive with respect to random parameter variations, deterministic substitute problems are needed. Based on the distribution of the random data, and using decision theoretical concepts, optimization problems under stochastic uncertainty are converted into deterministic substitute problems. Due to the occurring probabilities and expectations, approximative solution techniques must be applied. Deterministic and stochastic approximation methods and their analytical properties are provided: Taylor expansion, regression and response surface methods, probability inequalities, First Order Reliability Methods, convex approximation/deterministic descent directions/efficient points, stochastic approximation methods, differentiation of probability and mean value functions. Convergence results of the resulting iterative solution procedures are given.
Methods for euclidean geometry
Byer, Owen; Smeltzer, Deirdre L
2010-01-01
Euclidean plane geometry is one of the oldest and most beautiful topics in mathematics. Instead of carefully building geometries from axiom sets, this book uses a wealth of methods to solve problems in Euclidean geometry. Many of these methods arose where existing techniques proved inadequate. In several cases, the new ideas used in solving specific problems later developed into independent areas of mathematics. This book is primarily a geometry textbook, but studying geometry in this way will also develop students' appreciation of the subject and of mathematics as a whole. For instance, despite the fact that the analytic method has been part of mathematics for four centuries, it is rarely a tool a student considers using when faced with a geometry problem. Methods for Euclidean Geometry explores the application of a broad range of mathematical topics to the solution of Euclidean problems.
Nölting, Bengt
2010-01-01
Incorporating recent dramatic advances, this textbook presents a fresh and timely introduction to modern biophysical methods. An array of new, faster and higher-power biophysical methods now enables scientists to examine the mysteries of life at a molecular level. This innovative text surveys and explains the ten key biophysical methods, including those related to biophysical nanotechnology, scanning probe microscopy, X-ray crystallography, ion mobility spectrometry, mass spectrometry, proteomics, and protein folding and structure. Incorporating much information previously unavailable in tutorial form, Nölting employs worked examples and about 270 illustrations to fully detail the techniques and their underlying mechanisms. Methods in Modern Biophysics is written for advanced undergraduate and graduate students, postdocs, researchers, lecturers, and professors in biophysics, biochemistry and related fields. Special features in the 3rd edition: Introduces rapid partial protein ladder sequencing - an important...
Concrete compositions and methods
Chen, Irvin; Lee, Patricia Tung; Patterson, Joshua
2015-06-23
Provided herein are compositions, methods, and systems for cementitious compositions containing calcium carbonate compositions and aggregate. The compositions find use in a variety of applications, including use in a variety of building materials and building applications.
Bardenet, R.
2012-01-01
ISBN:978-2-7598-1032-1; International audience; Bayesian inference often requires integrating some function with respect to a posterior distribution. Monte Carlo methods are sampling algorithms that allow to compute these integrals numerically when they are not analytically tractable. We review here the basic principles and the most common Monte Carlo algorithms, among which rejection sampling, importance sampling and Monte Carlo Markov chain (MCMC) methods. We give intuition on the theoretic...
Skribans, V.
2002-01-01
The paper comprises three parts: description of the forecasting conception, classification of forecasting methods, and the general forecasting model. The first part deals with the definition of business forecasting, the second classifies and deals in more detail with the most frequently practiced forecasting methods and comes up with recommendations how to apply them in specific situations. The third part present the analysis of newly established forecasting model.
Bidirectional beam propagation method
Kaczmarski, P.; Lagasse, P. E.
1988-05-01
A bidirectional extension of the beam propagation method (BPM) to optical waveguides with a longitudinal discontinuity is presented. The algorithm is verified by computing a reflection of the TE(0) mode from a semiconductor laser facet. The bidirectional BPM is applicable to other configurations such as totally reflecting waveguide mirrors, an abruption transition in a waveguide, or a waveguide with many discontinuities generating multiple reflections. The method can also be adapted to TM polarization.
Henn, Fritz
2013-04-09
Methods for treatment of depression-related mood disorders in mammals, particularly humans are disclosed. The methods of the invention include administration of compounds capable of enhancing glutamate transporter activity in the brain of mammals suffering from depression. ATP-sensitive K.sup.+ channel openers and .beta.-lactam antibiotics are used to enhance glutamate transport and to treat depression-related mood disorders and depressive symptoms.
Henn, Fritz [East Patchogue, NY
2012-01-24
Methods for treatment of depression-related mood disorders in mammals, particularly humans are disclosed. The methods of the invention include administration of compounds capable of enhancing glutamate transporter activity in the brain of mammals suffering from depression. ATP-sensitive K.sup.+ channel openers and .beta.-lactam antibiotics are used to enhance glutamate transport and to treat depression-related mood disorders and depressive symptoms.
Schaumburg-Müller, Sten
2014-01-01
On the basis on 1) the Danish legal writer A.S.Ørsted (1778-1860) and 2) an enquete among present day Danish legal scholars, the contribution deals with special traits in Danish legal method......On the basis on 1) the Danish legal writer A.S.Ørsted (1778-1860) and 2) an enquete among present day Danish legal scholars, the contribution deals with special traits in Danish legal method...
Allen, Scott D.; Simoneau, Christopher A.; Keefe, William D.; Conuel, Jeff R.
2016-12-06
The present invention provides methods for reducing induction periods in epoxide-CO.sub.2 copolymerizations. In certain embodiments, the methods include the step of contacting an epoxide with CO.sub.2 in the presence of two catalysts: an epoxide hydrolysis catalyst and an epoxide CO.sub.2 copolymerization catalyst. In another aspect, the invention provides catalyst compositions comprising a mixture of an epoxide hydrolysis catalyst and an epoxide CO.sub.2 copolymerization catalyst.
Jandová, Pavlína
2007-01-01
Traditional marketing methods are losing their effectiveness and credibility. It has been worse and worse to communicate with customers, and marketers are therefore looking for new techniques and way how to appeal buyers. They turn to the use of modern marketing methods, which typical features are possibility of accurate targeting and low costs, and, also, the fact that they are still not considered being a classic promotion. In the theoretical part of the diploma thesis the alternative marke...
Painful Bile Extraction Methods
无
2006-01-01
It was only in the past 20 years that countries in Asia began to search for an alternative to protect moon bears from being killed for their bile and other body parts. In the early 1980s, a new method of extracting bile from living bears was developed in North Korea. In 1983, Chinese scientists imported this technique from North Korea. According to the Animals Asia Foundation, the most original method of bile extraction is to embed a latex catheter, a narrow rubber
[Unproven methods in oncology].
Jallut, O; Guex, P; Barrelet, L
1984-09-08
As in some other chronic diseases (rheumatism, multiple sclerosis, etc.), unproven methods of diagnosis and treatment have long been current in cancer. Since 1960 the American Cancer Society has published an abundant literature on these "unproven methods", which serves as a basis for a historical review: some substances (Krebiozen, Laetrile) have enjoyed tremendous if shortlived success. The present trend is back to nature and "mild medicine". The proponents of this so-called natural medicine are often disciples of a pseudoscientific religion using irrational arguments. Direct attacks on these erroneous theories and their public refutation fail to convince the adepts, who trust in these methods and are not amenable to a scientific approach. Study of their psychological motivations reveals that in fact they seek something more reassuring than plain medical explanation which is aware of its limits. They feel reassured by theories which often bear some resemblance to the old popular medicine. To protect patients against these dangerous methods and all the disillusionment they entail, the Swiss Society of Oncology and the Swiss Cancer League have decided to gather information and draw up a descriptive list of the commonest unproven methods in Switzerland (our File No. 2, "Total anti-cancer cure", is given as an example). The files are published in French, German and English and are available to physicians, nursing teams, and also patients who wish to have more objective information on these methods.
Multicriteria identification sets method
Kamenev, G. K.
2016-11-01
A multicriteria identification and prediction method for mathematical models of simulation type in the case of several identification criteria (error functions) is proposed. The necessity of the multicriteria formulation arises, for example, when one needs to take into account errors of completely different origins (not reducible to a single characteristic) or when there is no information on the class of noise in the data to be analyzed. An identification sets method is described based on the approximation and visualization of the multidimensional graph of the identification error function and sets of suboptimal parameters. This method allows for additional advantages of the multicriteria approach, namely, the construction and visual analysis of the frontier and the effective identification set (frontier and the Pareto set for identification criteria), various representations of the sets of Pareto effective and subeffective parameter combinations, and the corresponding predictive trajectory tubes. The approximation is based on the deep holes method, which yields metric ɛ-coverings with nearly optimal properties, and on multiphase approximation methods for the Edgeworth-Pareto hull. The visualization relies on the approach of interactive decision maps. With the use of the multicriteria method, multiple-choice solutions of identification and prediction problems can be produced and justified by analyzing the stability of the optimal solution not only with respect to the parameters (robustness with respect to data) but also with respect to the chosen set of identification criteria (robustness with respect to the given collection of functionals).
[Barrier methods of contraception].
Goldsmith, A; Edelman, D A
1982-01-01
Vaginal methods of contraception were the earliest types used and some references to them date back to antiquity. Most of the vaginal contraceptive agents identified by the ancient Greeks, Indians, Japanese, and Chinese have been found in modern laboratory tests to have spermicidal properties, but it is doubtful that the methods were fully reliable or were used by many people. During the 19th century the condom, vaginal spermicides, and diaphragm became available. The development of nonoxynol-9 and other nonirritating but effective spermicidal agents improved vaginal contraceptives greatly by the 1950s, but starting in the 1960s newer methods began to replace the vaginal methods. Interest in barrier methods has been reawakened somewhat by concern about the health effects of hormonal methods. At present all barrier methods leave something to be desired. Failure rates of 3-30% for barrier methods in general have been estimated, but the higher rates are believed due to incorrect or inconsistent use. Theoretical failure rates of condoms and diaphragms have been estimated at 3/100 women-years, but in actual use failure rates may reach 15 for condoms and 13 for diaphragms used with spermicides. Use-effectiveness rates are greatly influenced by motivation. For a variety of reasons, the acceptability of barrier methods is low, especially in developing countries. New developments in spermicidal agents include sperm inhibitors, which impede the fertilizing capacity of sperm rather than attempting a spermicidal effect; a number of such agents have been studied and have proven more effective in animal tests than conventional spermicides. Neosampoon, a new spermicidal foam, has attracted an increasing number of users, especially in developing countries. A new condom, made of thin polymers and containing a standard dose of nonoxynol-9, has been designed to dissolve in the vaginal fluid. Further studies are needed of its acceptability, efficacy, and side effects before it becomes
Henke, Luke
2010-01-01
The ICARE method is a flexible, widely applicable method for systems engineers to solve problems and resolve issues in a complete and comprehensive manner. The method can be tailored by diverse users for direct application to their function (e.g. system integrators, design engineers, technical discipline leads, analysts, etc.). The clever acronym, ICARE, instills the attitude of accountability, safety, technical rigor and engagement in the problem resolution: Identify, Communicate, Assess, Report, Execute (ICARE). This method was developed through observation of Space Shuttle Propulsion Systems Engineering and Integration (PSE&I) office personnel approach in an attempt to succinctly describe the actions of an effective systems engineer. Additionally it evolved from an effort to make a broadly-defined checklist for a PSE&I worker to perform their responsibilities in an iterative and recursive manner. The National Aeronautics and Space Administration (NASA) Systems Engineering Handbook states, engineering of NASA systems requires a systematic and disciplined set of processes that are applied recursively and iteratively for the design, development, operation, maintenance, and closeout of systems throughout the life cycle of the programs and projects. ICARE is a method that can be applied within the boundaries and requirements of NASA s systems engineering set of processes to provide an elevated sense of duty and responsibility to crew and vehicle safety. The importance of a disciplined set of processes and a safety-conscious mindset increases with the complexity of the system. Moreover, the larger the system and the larger the workforce, the more important it is to encourage the usage of the ICARE method as widely as possible. According to the NASA Systems Engineering Handbook, elements of a system can include people, hardware, software, facilities, policies and documents; all things required to produce system-level results, qualities, properties, characteristics
VALUATION METHODS- LITERATURE REVIEW
Dorisz Talas
2015-07-01
Full Text Available This paper is a theoretical overview of the often used valuation methods with the help of which the value of a firm or its equity is calculated. Many experts (including Aswath Damodaran, Guochang Zhang and CA Hozefa Natalwala classify the methods. The basic models are based on discounted cash flows. The main method uses the free cash flow for valuation, but there are some newer methods that reveal and correct the weaknesses of the traditional models. The valuation of flexibility of management can be conducted mainly with real options. This paper briefly describes the essence of the Dividend Discount Model, the Free Cash Flow Model, the benefit from using real options and the Residual Income Model. There are a few words about the Adjusted Present Value approach as well. Different models uses different premises, and an overall truth is that if the required premises are real and correct, the value will be appropriately accurate. Another important condition is that experts, analysts should choose between the models on the basis of the purpose of valuation. Thus there are no good or bad methods, only methods that fit different goals and aims. The main task is to define exactly the purpose, then to find the most appropriate valuation technique. All the methods originates from the premise that the value of an asset is the present value of its future cash flows. According to the different points of view of different techniques the resulted values can be also differed from each other. Valuation models and techniques should be adapted to the rapidly changing world, but the basic statements remain the same. On the other hand there is a need for more accurate models in order to help investors get as many information as they could. Today information is one of the most important resources and financial models should keep up with this trend.
Molecular methods for biofilms
Ferrera, Isabel
2014-08-30
This chapter deals with both classical and modern molecular methods that can be useful for the identification of microorganisms, elucidation and comparison of microbial communities, and investigation of their diversity and functions. The most important and critical steps necessary for all molecular methods is DNA isolation from microbial communities and environmental samples; these are discussed in the first part. The second part provides an overview over DNA polymerase chain reaction (PCR) amplification and DNA sequencing methods. Protocols and analysis software as well as potential pitfalls associated with application of these methods are discussed. Community fingerprinting analyses that can be used to compare multiple microbial communities are discussed in the third part. This part focuses on Denaturing Gradient Gel Electrophoresis (DGGE), Terminal Restriction Fragment Length Polymorphism (T-RFLP) and Automated rRNA Intergenic Spacer Analysis (ARISA) methods. In addition, classical and next-generation metagenomics methods are presented. These are limited to bacterial artificial chromosome and Fosmid libraries and Sanger and next-generation 454 sequencing, as these methods are currently the most frequently used in research. Isolation of nucleic acids: This chapter discusses, the most important and critical steps necessary for all molecular methods is DNA isolation from microbial communities and environmental samples. Nucleic acid isolation methods generally include three steps: cell lysis, removal of unwanted substances, and a final step of DNA purification and recovery. The first critical step is the cell lysis, which can be achieved by enzymatic or mechanical procedures. Removal of proteins, polysaccharides and other unwanted substances is likewise important to avoid their interference in subsequent analyses. Phenol-chloroform-isoamyl alcohol is commonly used to recover DNA, since it separates nucleic acids into an aqueous phase and precipitates proteins and
New oligosaccharyltransferase assay method.
Kohda, Daisuke; Yamada, Masaki; Igura, Mayumi; Kamishikiryo, Jun; Maenaka, Katsumi
2007-11-01
We developed a new in vitro assay for oligosaccharyltransferase (OST), which catalyzes the transfer of preassembled oligosaccharides on lipid carriers onto asparagine residues in polypeptide chains. The asparagine residues reside in the sequon, Asn-X-Thr/Ser, where X can be any amino acid residue except Pro. We demonstrate the potency of our assay using the OST from yeast. In our method, polyacrylamide gel electrophoresis is used to separate the glycopeptide products from the peptide substrates. The substrate peptide is fluorescently labeled and the formation of glycopeptides is analyzed by fluorescence gel imaging. Two in vitro OST assay methods are now widely used, but both the methods depend on previous knowledge of the oligosaccharide moiety: One method uses lectin binding as the separation mechanism and the other method uses biosynthetically or chemoenzymatically synthesized lipid-linked oligosaccharides as donors. N-linked protein glycosylation is found in all three domains of life, but little is known about the N-glycosylation in Archaea. Thus, our new assay, which does not require a priori knowledge of the oligosaccharides, will be useful in such cases. Indeed, we have detected the OST activity in the membrane fraction from a hyperthermophilic archaeon, Pyrococcus furiosus.
Methods for Neutron Spectrometry
Brockhouse, Bertram N.
1961-01-09
The appropriate theories and the general philosophy of methods of measurement and treatment of data neutron spectrometry are discussed. Methods of analysis of results for liquids using the Van Hove formulation, and for crystals using the Born-von Karman theory, are reviewed. The most useful of the available methods of measurement are considered to be the crystal spectrometer methods and the pulsed monoenergetic beam/time-of-flight method. Pulsed-beam spectrometers have the advantage of higher counting rates than crystal spectrometers, especially in view of the fact that simultaneous measurements in several counters at different angles of scattering are possible in pulsed-beam spectrometers. The crystal spectrometer permits several valuable new types of specialized experiments to be performed, especially energy distribution measurements at constant momentum transfer. The Chalk River triple-axis crystal-spectrometer is discussed, with reference to its use in making the specialized experiments. The Chalk River rotating crystal (pulsed-beam) spectrometer is described, and a comparison of this type instrument with other pulsed-beam spectrometers is made. A partial outline of the theory of operation of rotating-crystal spectrometers is presented. The use of quartz-crystal filters for fast neutron elimination and for order elimination is discussed. (auth)
Rice, J P; Saccone, N L; Corbett, J
2001-01-01
The lod score method originated in a seminal article by Newton Morton in 1955. The method is broadly concerned with issues of power and the posterior probability of linkage, ensuring that a reported linkage has a high probability of being a true linkage. In addition, the method is sequential, so that pedigrees or lod curves may be combined from published reports to pool data for analysis. This approach has been remarkably successful for 50 years in identifying disease genes for Mendelian disorders. After discussing these issues, we consider the situation for complex disorders, where the maximum lod score (MLS) statistic shares some of the advantages of the traditional lod score approach but is limited by unknown power and the lack of sharing of the primary data needed to optimally combine analytic results. We may still learn from the lod score method as we explore new methods in molecular biology and genetic analysis to utilize the complete human DNA sequence and the cataloging of all human genes.
Fashion, Mediations & Method Assemblages
Sommerlund, Julie; Jespersen, Astrid Pernille
, respectively. The paper thus takes on aesthetics and the social in a manner closely related to a core argument of STS - namely that the scientific fact, and the social processes of constructing, distributing, and using that fact, are co-constructed (Callon, 1986; Latour, 1993). The paper thus contributes......, it is an important ambition of this paper to go into a methodological discussion of how "that which effectively happens" can be approached. To this end, the paper will combine Hennion's term of the "mediator" with John Laws methodological term of "method assemblages". Method assemblages is a suggested as a way...... of handling multiple, fluid realities with multiple, fluid methods. Empirically, the paper works with mediation in fashion - that is efforts the active shaping of relations between producer and consumer through communication, marketing and PR. Fashion mediation is by no means simple, but organise complex...
Cytoskeleton - Methods and Protocols
CarloAlberto Redi
2010-03-01
Full Text Available Cytoskeleton - Methods and ProtocolsSecond edition, 2010; Ray H. Gavin (Ed; Springer Protocols methods in molecular biology, vol. 586 Humana press, Totowa, New Jersey (USA; Pages: 390; €95.44; ISBN: 978-1-60761-375-6Ray H. Gavin, from the Brooklyn College of The City University of New York, Brooklyn, NY, USA, wrote a few line as preface of this book. This is quite understandable: there is not a great need of words when there are facts that sustain and favour the dissemination of a cultural product. This is the case of the second edition of Cytoskeleton - Methods and Protocols, which appears just ten years after the first edition...
Adéla Volfová
2012-10-01
Full Text Available Geostatistics is a scientific field which provides methods for processing spatial data. In our project, geostatistics is used as a tool for describing spatial continuity and making predictions of some natural phenomena. An open source statistical project called R is used for all calculations. Listeners will be provided with a brief introduction to R and its geostatistical packages and basic principles of kriging and cokriging methods. Heavy mathematical background is omitted due to its complexity. In the second part of the presentation, several examples are shown of how to make a prediction in the whole area of interest where observations were made in just a few points. Results of these methods are compared.
Saadd, Y.
1994-12-31
In spite of the tremendous progress achieved in recent years in the general area of iterative solution techniques, there are still a few obstacles to the acceptance of iterative methods in a number of applications. These applications give rise to very indefinite or highly ill-conditioned non Hermitian matrices. Trying to solve these systems with the simple-minded standard preconditioned Krylov subspace methods can be a frustrating experience. With the mathematical and physical models becoming more sophisticated, the typical linear systems which we encounter today are far more difficult to solve than those of just a few years ago. This trend is likely to accentuate. This workshop will discuss (1) these applications and the types of problems that they give rise to; and (2) recent progress in solving these problems with iterative methods. The workshop will end with a hopefully stimulating panel discussion with the speakers.
Le, Khanh Chau
2012-01-01
The above examples should make clear the necessity of understanding the mechanism of vibrations and waves in order to control them in an optimal way. However vibrations and waves are governed by differential equations which require, as a rule, rather complicated mathematical methods for their analysis. The aim of this textbook is to help students acquire both a good grasp of the first principles from which the governing equations can be derived, and the adequate mathematical methods for their solving. Its distinctive features, as seen from the title, lie in the systematic and intensive use of Hamilton's variational principle and its generalizations for deriving the governing equations of conservative and dissipative mechanical systems, and also in providing the direct variational-asymptotic analysis, whenever available, of the energy and dissipation for the solution of these equations. It will be demonstrated that many well-known methods in dynamics like those of Lindstedt-Poincare, Bogoliubov-Mitropolsky, Ko...
Le, Khanh Chau
2014-01-01
Energy Methods in Dynamics is a textbook based on the lectures given by the first author at Ruhr University Bochum, Germany. Its aim is to help students acquire both a good grasp of the first principles from which the governing equations can be derived, and the adequate mathematical methods for their solving. Its distinctive features, as seen from the title, lie in the systematic and intensive use of Hamilton's variational principle and its generalizations for deriving the governing equations of conservative and dissipative mechanical systems, and also in providing the direct variational-asymptotic analysis, whenever available, of the energy and dissipation for the solution of these equations. It demonstrates that many well-known methods in dynamics like those of Lindstedt-Poincare, Bogoliubov-Mitropolsky, Kolmogorov-Arnold-Moser (KAM), Wentzel–Kramers–Brillouin (WKB), and Whitham are derivable from this variational-asymptotic analysis. This second edition includes the solutions to all exercises as w...
Decker, David L.; Lyles, Brad F.; Purcell, Richard G.; Hershey, Ronald Lee
2017-03-07
In one embodiment, the present disclosure provides an apparatus and method for supporting a tubing bundle during installation or removal. The apparatus includes a clamp for securing the tubing bundle to an external wireline. In various examples, the clamp is external to the tubing bundle or integral with the tubing bundle. According to one method, a tubing bundle and wireline are deployed together and the tubing bundle periodically secured to the wireline using a clamp. In another embodiment, the present disclosure provides an apparatus and method for coupling conduit segments together. A first pump obtains a sample and transmits it through a first conduit to a reservoir accessible by a second pump. The second pump further conducts the sample from the reservoir through a second conduit. In a specific example, one or more clamps are used to connect the first and/or second conduits to an external wireline.
Liseikin, Vladimir D
2017-01-01
This new edition provides a description of current developments relating to grid methods, grid codes, and their applications to actual problems. Grid generation methods are indispensable for the numerical solution of differential equations. Adaptive grid-mapping techniques, in particular, are the main focus and represent a promising tool to deal with systems with singularities. This 3rd edition includes three new chapters on numerical implementations (10), control of grid properties (11), and applications to mechanical, fluid, and plasma related problems (13). Also the other chapters have been updated including new topics, such as curvatures of discrete surfaces (3). Concise descriptions of hybrid mesh generation, drag and sweeping methods, parallel algorithms for mesh generation have been included too. This new edition addresses a broad range of readers: students, researchers, and practitioners in applied mathematics, mechanics, engineering, physics and other areas of applications.
Knox, J.A.; Lasater, R.M.
1966-11-22
Chemical compositions and methods are provided for treating underground formations to render their surfaces water-repellent or preferentially oil-wettable. Previous methods have provided only temporary water-repellency because they do not actually act chemically with the reservoir rock. This improvement is obtained by using a treating agent which does not form a precipitate upon hydrolysis with water, such as a liquid organo-halogen- silane or its ester. A water-soluble anhydrous solvent which is nonreactive with the silane is used as a carrier. This method may be used for treating non-oil-bearing aquifers for increasing the flow rate of water, such as in water supply wells, or in water input rate, such as in water disposal wells. (10 claims)
Olivarius, Signe
of the transcriptome, 5’ end capture of RNA is combined with next-generation sequencing for high-throughput quantitative assessment of transcription start sites by two different methods. The methods presented here allow for functional investigation of coding as well as noncoding RNA and contribute to future......While increasing evidence appoints diverse types of RNA as key players in the regulatory networks underlying cellular differentiation and metabolism, the potential functions of thousands of conserved RNA structures encoded in mammalian genomes remain to be determined. Since the functions of most...... RNAs rely on interactions with proteins, the establishment of protein-binding profiles is essential for the characterization of RNAs. Aiming to facilitate RNA analysis, this thesis introduces proteomics- as well as transcriptomics-based methods for the functional characterization of RNA. First, RNA...
Model Correction Factor Method
Christensen, Claus; Randrup-Thomsen, Søren; Morsing Johannesen, Johannes
1997-01-01
The model correction factor method is proposed as an alternative to traditional polynomial based response surface techniques in structural reliability considering a computationally time consuming limit state procedure as a 'black box'. The class of polynomial functions is replaced by a limit...... statebased on an idealized mechanical model to be adapted to the original limit state by the model correction factor. Reliable approximations are obtained by iterative use of gradient information on the original limit state function analogously to previous response surface approaches. However, the strength...... of the model correction factor method, is that in simpler form not using gradient information on the original limit state function or only using this information once, a drastic reduction of the number of limit state evaluation is obtained together with good approximations on the reliability. Methods...
Splines and variational methods
Prenter, P M
2008-01-01
One of the clearest available introductions to variational methods, this text requires only a minimal background in calculus and linear algebra. Its self-contained treatment explains the application of theoretic notions to the kinds of physical problems that engineers regularly encounter. The text's first half concerns approximation theoretic notions, exploring the theory and computation of one- and two-dimensional polynomial and other spline functions. Later chapters examine variational methods in the solution of operator equations, focusing on boundary value problems in one and two dimension
Nonparametric statistical methods
Hollander, Myles; Chicken, Eric
2013-01-01
Praise for the Second Edition"This book should be an essential part of the personal library of every practicing statistician."-Technometrics Thoroughly revised and updated, the new edition of Nonparametric Statistical Methods includes additional modern topics and procedures, more practical data sets, and new problems from real-life situations. The book continues to emphasize the importance of nonparametric methods as a significant branch of modern statistics and equips readers with the conceptual and technical skills necessary to select and apply the appropriate procedures for any given sit
Smith, C.S.
1959-08-01
A method is described for rolling uranium metal at relatively low temperatures and under non-oxidizing conditions. The method involves the steps of heating the uranium to 200 deg C in an oil bath, withdrawing the uranium and permitting the oil to drain so that only a thin protective coating remains and rolling the oil coated uranium at a temperature of 200 deg C to give about a 15% reduction in thickness at each pass. The operation may be repeated to accomplish about a 90% reduction without edge cracking, checking or any appreciable increase in brittleness.
Electrorheological fluids and methods
Green, Peter F.; McIntyre, Ernest C.
2015-06-02
Electrorheological fluids and methods include changes in liquid-like materials that can flow like milk and subsequently form solid-like structures under applied electric fields; e.g., about 1 kV/mm. Such fluids can be used in various ways as smart suspensions, including uses in automotive, defense, and civil engineering applications. Electrorheological fluids and methods include one or more polar molecule substituted polyhedral silsesquioxanes (e.g., sulfonated polyhedral silsesquioxanes) and one or more oils (e.g., silicone oil), where the fluid can be subjected to an electric field.
Tautomerism methods and theories
Antonov, Liudmil
2013-01-01
Covering the gap between basic textbooks and over-specialized scientific publications, this is the first reference available to describe this interdisciplinary topic for PhD students and scientists starting in the field. The result is an introductory description providing suitable practical examples of the basic methods used to study tautomeric processes, as well as the theories describing the tautomerism and proton transfer phenomena. It also includes different spectroscopic methods for examining tautomerism, such as UV-VIs, time-resolved fluorescence spectroscopy, and NMR spectrosc
Unorthodox theoretical methods
Nedd, Sean [Iowa State Univ., Ames, IA (United States)
2012-01-01
The use of the ReaxFF force field to correlate with NMR mobilities of amine catalytic substituents on a mesoporous silica nanosphere surface is considered. The interfacing of the ReaxFF force field within the Surface Integrated Molecular Orbital/Molecular Mechanics (SIMOMM) method, in order to replicate earlier SIMOMM published data and to compare with the ReaxFF data, is discussed. The development of a new correlation consistent Composite Approach (ccCA) is presented, which incorporates the completely renormalized coupled cluster method with singles, doubles and non-iterative triples corrections towards the determination of heats of formations and reaction pathways which contain biradical species.
Dunn, William L
2012-01-01
Exploring Monte Carlo Methods is a basic text that describes the numerical methods that have come to be known as "Monte Carlo." The book treats the subject generically through the first eight chapters and, thus, should be of use to anyone who wants to learn to use Monte Carlo. The next two chapters focus on applications in nuclear engineering, which are illustrative of uses in other fields. Five appendices are included, which provide useful information on probability distributions, general-purpose Monte Carlo codes for radiation transport, and other matters. The famous "Buffon's needle proble
Steijn, Arthur
2016-01-01
Contemporary scenography often consists of video-projected motion graphics. The field is lacking in academic methods and rigour: descriptions and models relevant for the creation as well as in the analysis of existing works. In order to understand the phenomenon of motion graphics in a scenographic...... construction as a support to working systematically practice-led research project. The design model is being developed through design laboratories and workshops with students and professionals who provide feedback that lead to incremental improvements. Working with this model construction-as-method reveals...
Wong, Pak C.; Mackey, Patrick S.; Perrine, Kenneth A.; Foote, Harlan P.; Thomas, James J.
2008-12-23
Methods for visualizing a graph by automatically drawing elements of the graph as labels are disclosed. In one embodiment, the method comprises receiving node information and edge information from an input device and/or communication interface, constructing a graph layout based at least in part on that information, wherein the edges are automatically drawn as labels, and displaying the graph on a display device according to the graph layout. In some embodiments, the nodes are automatically drawn as labels instead of, or in addition to, the label-edges.
Methods of Multivariate Analysis
Rencher, Alvin C
2012-01-01
Praise for the Second Edition "This book is a systematic, well-written, well-organized text on multivariate analysis packed with intuition and insight . . . There is much practical wisdom in this book that is hard to find elsewhere."-IIE Transactions Filled with new and timely content, Methods of Multivariate Analysis, Third Edition provides examples and exercises based on more than sixty real data sets from a wide variety of scientific fields. It takes a "methods" approach to the subject, placing an emphasis on how students and practitioners can employ multivariate analysis in real-life sit
Methods for pretreating biomass
Balan, Venkatesh; Dale, Bruce E; Chundawat, Shishir; Sousa, Leonardo
2017-05-09
A method for pretreating biomass is provided, which includes, in a reactor, allowing gaseous ammonia to condense on the biomass and react with water present in the biomass to produce pretreated biomass, wherein reactivity of polysaccharides in the biomass is increased during subsequent biological conversion as compared to the reactivity of polysaccharides in biomass which has not been pretreated. A method for pretreating biomass with a liquid ammonia and recovering the liquid ammonia is also provided. Related systems which include a biochemical or biofuel production facility are also disclosed.
Apoptosis - Methods and Protocols
CarloAlberto Redi
2010-03-01
Full Text Available Apoptosis - Methods and ProtocolsSecond edition, 2009; Peter Erhardt and Ambrus Toth (Eds; Springer Protocols - Methods in molecular biology, vol. 559; Humana press, Totowa, New Jersey (USA; Pages: 400; €88.35; ISBN: 978-1-60327-016-8The editors rightly begin the preface telling us that: “The ability to detect and quantify apoptosis, to understand its biochemistry and to identify its regulatory genes and proteins is crucial to biomedical research”. Nowadays this is a grounding concept of biology and medicine. What is particularly remarkable...
Practical methods of optimization
Fletcher, R
2013-01-01
Fully describes optimization methods that are currently most valuable in solving real-life problems. Since optimization has applications in almost every branch of science and technology, the text emphasizes their practical aspects in conjunction with the heuristics useful in making them perform more reliably and efficiently. To this end, it presents comparative numerical studies to give readers a feel for possibile applications and to illustrate the problems in assessing evidence. Also provides theoretical background which provides insights into how methods are derived. This edition offers rev
Essential numerical computer methods
Johnson, Michael L
2010-01-01
The use of computers and computational methods has become ubiquitous in biological and biomedical research. During the last 2 decades most basic algorithms have not changed, but what has is the huge increase in computer speed and ease of use, along with the corresponding orders of magnitude decrease in cost. A general perception exists that the only applications of computers and computer methods in biological and biomedical research are either basic statistical analysis or the searching of DNA sequence data bases. While these are important applications they only scratch the surface
Welbourne, D
1965-01-01
Analogue Computing Methods presents the field of analogue computation and simulation in a compact and convenient form, providing an outline of models and analogues that have been produced to solve physical problems for the engineer and how to use and program the electronic analogue computer. This book consists of six chapters. The first chapter provides an introduction to analogue computation and discusses certain mathematical techniques. The electronic equipment of an analogue computer is covered in Chapter 2, while its use to solve simple problems, including the method of scaling is elaborat
Patton, Michael Quinn
1980-01-01
Methodological paradigms in evaluation research are discussed. This article is a response to the attacks on paradigmatic perspectives made by Reichardt and Cook in the opening chapter of their edited book, "Qualitative and Quantitative Methods in Evaluation Research." (Author/GK)
communication method and apparatus
2005-01-01
The present invention relates to a non-lingual communication method and apparatus, wherein a physical or physiological signal consciously created by a first subject (1) is detected and converted into a transmitted output signal presented to a second subject (7) in order to communicate information...
METHOD OF CENTRIFUGE OPERATION
Cohen, K.
1960-05-10
A method of isotope separation is described in which two streams are flowed axially of, and countercurrently through, a cylindrical centrifuge bowl. Under the influence of a centrifugal field, the light fraction is concentrated in a stream flowing through the central portion of the bowl, whereas the heavy fraction is concentrated in a stream at the periphery thereof.
Ferrari's Method and Technology
Althoen, Steve
2005-01-01
Some tips that combine knowledge of mathematics history and technology for adapting Ferrar's method to factor quintics with a TI-83 graphing calculator are presented. A demonstration on the use of the root finder and regression capabilities of the graphing calculator are presented, so that the tips can be easily adapted for any graphing calculator…
Pressley, Michael; And Others
1982-01-01
Available experimental evidence is reviewed concerning the keyword method, a two-stage procedure for remembering materials having an associative component. The review examines subjects' memory for definitions, given vocabulary words; subjects' learning of other aspects of vocabulary, given definitions; group-administered keyword studies; and…
Andersson, Pher G
2008-01-01
With its comprehensive overview of modern reduction methods, this book features high quality contributions allowing readers to find reliable solutions quickly and easily. The monograph treats the reduction of carbonyles, alkenes, imines and alkynes, as well as reductive aminations and cross and heck couplings, before finishing off with sections on kinetic resolutions and hydrogenolysis. An indispensable lab companion for every chemist.
Isaacson, Eugene
1994-01-01
This excellent text for advanced undergraduates and graduate students covers norms, numerical solution of linear systems and matrix factoring, iterative solutions of nonlinear equations, eigenvalues and eigenvectors, polynomial approximation, and other topics. It offers a careful analysis and stresses techniques for developing new methods, plus many examples and problems. 1966 edition.
Pinar, William Frederick
In this presentation the author paints a conceptual portrait of his evolving relationships to his formal studies and thereby describes a method by which educators can reconceptualize the meaning of curriculum. By taking oneself and one's existential experience as a data source and using the psychoanalytical technique of free association, one can…
Universal Image Steganalytic Method
V. Banoci
2014-12-01
Full Text Available In the paper we introduce a new universal steganalytic method in JPEG file format that is detecting well-known and also newly developed steganographic methods. The steganalytic model is trained by MHF-DZ steganographic algorithm previously designed by the same authors. The calibration technique with the Feature Based Steganalysis (FBS was employed in order to identify statistical changes caused by embedding a secret data into original image. The steganalyzer concept utilizes Support Vector Machine (SVM classification for training a model that is later used by the same steganalyzer in order to identify between a clean (cover and steganographic image. The aim of the paper was to analyze the variety in accuracy of detection results (ACR while detecting testing steganographic algorithms as F5, Outguess, Model Based Steganography without deblocking, JP Hide and Seek which represent the generally used steganographic tools. The comparison of four feature vectors with different lengths FBS (22, FBS (66 FBS(274 and FBS(285 shows promising results of proposed universal steganalytic method comparing to binary methods.
Methods Evolved by Observation
Montessori, Maria
2016-01-01
Montessori's idea of the child's nature and the teacher's perceptiveness begins with amazing simplicity, and when she speaks of "methods evolved," she is unveiling a methodological system for observation. She begins with the early childhood explosion into writing, which is a familiar child phenomenon that Montessori has written about…
Wölfel, Christiane; Merritt, T.
2013-01-01
. The card-based tools are explained in terms of five design dimensions including the intended purpose and scope of use, duration of use, methodology, customization, and formal/material qualities. Our analysis suggests three design patterns or archetypes for existing card-based design method tools...
Statistical methods in astronomy
Long, James P.; de Souza, Rafael S.
2017-01-01
We present a review of data types and statistical methods often encountered in astronomy. The aim is to provide an introduction to statistical applications in astronomy for statisticians and computer scientists. We highlight the complex, often hierarchical, nature of many astronomy inference problems and advocate for cross-disciplinary collaborations to address these challenges.
Aagaard, Jesper; Matthiesen, Noomi
2016-01-01
, and the method of participant observation is suggested as a viable approach to achieve this end. An empirical example of how authority is produced in a parent-teacher conference, not only through language but also through material objects and embodied being, is then presented. The article concludes by suggesting...
Research Methods in Sociolinguistics
Hernández-Campoy, Juan Manuel
2014-01-01
The development of Sociolinguistics has been qualitatively and quantitatively outstanding within Linguistic Science since its beginning in the 1950s, with a steady growth in both theoretical and methodological developments as well as in its interdisciplinary directions within the spectrum of language and society. Field methods in sociolinguistic…
Uspenskiy, S. I.; Yermakova, S. V.; Chaynova, L. D.; Mitkin, A. A.; Gushcheva, T. M.; Strelkov, Y. K.; Tsvetkova, N. F.
1973-01-01
Various factors used in ergonomic research are given. They are: (1) anthrometric measurement, (2) polyeffector method of assessing the functional state of man, (3) galvanic skin reaction, (4) pneumography, (5) electromyography, (6) electrooculography, and (7) tachestoscopy. A brief summary is given of each factor and includes instrumentation and results.
2012-01-01
The present invention provides a method for sintering, comprising in the following order the steps of: providing a body in the green state or in the pre-sintered state on a support; providing a load on at least one spacer on the support such that the load is located above said body in the green...
Friend, Julie; Elander, Richard T.; Tucker, III; Melvin P.; Lyons, Robert C.
2010-10-26
A method for treating biomass was developed that uses an apparatus which moves a biomass and dilute aqueous ammonia mixture through reaction chambers without compaction. The apparatus moves the biomass using a non-compressing piston. The resulting treated biomass is saccharified to produce fermentable sugars.
Dasenbrock, Reed Way
1995-01-01
Examines literary theory's displacing of "method" in the New Historicist criticism. Argues that Stephen Greenblatt and Lee Paterson imply that no objective historical truth is possible and as a result do not give methodology its due weight in their criticism. Questions the theory of "truth" advanced in this vein of literary…
Software specification methods
Habrias, Henri
2010-01-01
This title provides a clear overview of the main methods, and has a practical focus that allows the reader to apply their knowledge to real-life situations. The following are just some of the techniques covered: UML, Z, TLA+, SAZ, B, OMT, VHDL, Estelle, SDL and LOTOS.
Progress in variational methods
2008-01-01
@@ The International Conference on Variational Methods (ICVAM) was held from May 20th to 26th in 2007 at the Chern Institute of Mathematics, Nankai University, Tianjin, China. Twenty eight invited speakers from ten countries and areas worldwide gave their lectures at the conference.
Collins, H. Dale; Gribble, R. Parks; Busse, Lawrence J.
1991-01-01
A method for providing an image of the human heart's electrical system derives time-of-flight data from an array of EKG electrodes and this data is transformed into phase information. The phase information, treated as a hologram, is reconstructed to provide an image in one or two dimensions of the electrical system of the functioning heart.
Quality of regularization methods
Bouwman, J.
1998-01-01
The solution of ill-posed problems is non-trivial in the sense that frequently applied methods like least-squares fail. The ill-posedness of the problem is refiected by very small changes in the input data which may result in very large changes in the output data. Hence, some sort of stabilization
Aagaard, Jesper; Matthiesen, Noomi
2016-01-01
, and the method of participant observation is suggested as a viable approach to achieve this end. An empirical example of how authority is produced in a parent-teacher conference, not only through language but also through material objects and embodied being, is then presented. The article concludes by suggesting...
Fact Sheet Proven Weight Loss Methods What can weight loss do for you? Losing weight can improve your health in a number of ways. ... limiting calories) usually isn’t enough to cause weight loss. But exercise plays an important part in helping ...
Research Methods in Sociolinguistics
Hernández-Campoy, Juan Manuel
2014-01-01
The development of Sociolinguistics has been qualitatively and quantitatively outstanding within Linguistic Science since its beginning in the 1950s, with a steady growth in both theoretical and methodological developments as well as in its interdisciplinary directions within the spectrum of language and society. Field methods in sociolinguistic…
Decker, David L.; Lyles, Brad F.; Purcell, Richard G.; Hershey, Ronald Lee
2013-04-16
The present disclosure provides an apparatus and method for coupling conduit segments together. A first pump obtains a sample and transmits it through a first conduit to a reservoir accessible by a second pump. The second pump further conducts the sample from the reservoir through a second conduit.
Photothermal methods in medicine
Murphy, John C.
2000-10-01
Photothermal imaging and spectroscopy are being applied to a variety of medical problems for diagnosis and therapy. This paper reviews some aspects of this field including the opportunities presented by non-optical sources and by use of detection methods targeted to the application.
Quality of regularization methods
Bouwman, J.
1998-01-01
The solution of ill-posed problems is non-trivial in the sense that frequently applied methods like least-squares fail. The ill-posedness of the problem is refiected by very small changes in the input data which may result in very large changes in the output data. Hence, some sort of stabilization o
John C Pfeiffer
2004-01-01
In the design/build (D/B) method of implementing plant construction projects, the owner contracts with the engineer/contractor or contractor/engineer company or team-depending upon who takes the lead in the project to develop...
Kuksin, Sergei; Maiocchi, Alberto
In this chapter we present a general method of constructing the effective equation which describes the behavior of small-amplitude solutions for a nonlinear PDE in finite volume, provided that the linear part of the equation is a hamiltonian system with a pure imaginary discrete spectrum. The effective equation is obtained by retaining only the resonant terms of the nonlinearity (which may be hamiltonian, or may be not); the assertion that it describes the limiting behavior of small-amplitude solutions is a rigorous mathematical theorem. In particular, the method applies to the three- and four-wave systems. We demonstrate that different possible types of energy transport are covered by this method, depending on whether the set of resonances splits into finite clusters (this happens, e.g. in case of the Charney-Hasegawa-Mima equation), or is connected (this happens, e.g. in the case of the NLS equation if the space-dimension is at least two). For equations of the first type the energy transition to high frequencies does not hold, while for equations of the second type it may take place. Our method applies to various weakly nonlinear wave systems, appearing in plasma, meteorology and oceanography.
Teaching Materials and Methods.
Physiologist, 1987
1987-01-01
Contains abstracts of presented papers which deal with teaching materials and methods in physiology. Includes papers on preconceptual notions in physiology, somatosensory activity recorded in the dorsal root ganglion of the bull frog, and the use of the Apple Macintosh microcomputer in teaching human anatomy and physiology. (TW)
Nevanlinna, O. [Helsinki Univ. of Technology, Espoo (Finland)
1994-12-31
This note summarizes some results on (a monitored version of) the Arnoldi method in Hilbert spaces. The interest in working in infinite dimensional spaces comes partly from the fact that only then can one have meaningful asymptotical statements (which hopefully give some light to the convergence of Arnoldi in large dimensional problems with iteration indices far less than the dimension).
Photovoltaic device and method
Cleereman, Robert; Lesniak, Michael J.; Keenihan, James R.; Langmaid, Joe A.; Gaston, Ryan; Eurich, Gerald K.; Boven, Michelle L.
2015-11-24
The present invention is premised upon an improved photovoltaic device ("PVD") and method of use, more particularly to an improved photovoltaic device with an integral locator and electrical terminal mechanism for transferring current to or from the improved photovoltaic device and the use as a system.
Healy, Richard W.; Scanlon, Bridget R.
2010-01-01
A water budget is an accounting of water movement into and out of, and storage change within, some control volume. Universal and adaptable are adjectives that reflect key features of water-budget methods for estimating recharge. The universal concept of mass conservation of water implies that water-budget methods are applicable over any space and time scales (Healy et al., 2007). The water budget of a soil column in a laboratory can be studied at scales of millimeters and seconds. A water-budget equation is also an integral component of atmospheric general circulation models used to predict global climates over periods of decades or more. Water-budget equations can be easily customized by adding or removing terms to accurately portray the peculiarities of any hydrologic system. The equations are generally not bound by assumptions on mechanisms by which water moves into, through, and out of the control volume of interest. So water-budget methods can be used to estimate both diffuse and focused recharge, and recharge estimates are unaffected by phenomena such as preferential flow paths within the unsaturated zone. Water-budget methods represent the largest class of techniques for estimating recharge. Most hydrologic models are derived from a water-budget equation and can therefore be classified as water-budget models. It is not feasible to address all water-budget methods in a single chapter. This chapter is limited to discussion of the “residual” water-budget approach, whereby all variables in a water-budget equation, except for recharge, are independently measured or estimated and recharge is set equal to the residual. This chapter is closely linked with Chapter 3, on modeling methods, because the equations presented here form the basis of many models and because models are often used to estimate individual components in water-budget studies. Water budgets for streams and other surface-water bodies are addressed in Chapter 4. The use of soil-water budgets and
Nonhazardous Urine Pretreatment Method
Akse, James R.; Holtsnider, John T.
2012-01-01
A method combines solid phase acidification with two non-toxic biocides to prevent ammonia volatilization and microbial proliferation. The safe, non-oxidizing biocide combination consists of a quaternary amine and a food preservative. This combination has exhibited excellent stabilization of both acidified and unacidified urine. During pretreatment tests, composite urine collected from donors was challenged with a microorganism known to proliferate in urine, and then was processed using the nonhazardous urine pre-treatment method. The challenge microorganisms included Escherichia coli, a common gram-negative bacteria; Enterococcus faecalis, a ureolytic gram-positive bacteria; Candida albicans, a yeast commonly found in urine; and Aspergillus niger, a problematic mold that resists urine pre-treatment. Urine processed in this manner remained microbially stable for over 57 days. Such effective urine stabilization was achieved using non-toxic, non-oxidizing biocides at higher pH (3.6 to 5.8) than previous methods in use or projected for use aboard the International Space Station (ISS). ISS urine pretreatment methods employ strong oxidants including ozone and hexavalent chromium (Cr(VI)), a carcinogenic material, under very acidic conditions (pH = 1.8 to 2.4). The method described here offers a much more benign chemical environment than previous pretreatment methods, and will lower equivalent system mass (ESM) by reducing containment volume and mass, system complexity, and crew time needed to handle pre-treatment chemicals. The biocides, being non-oxidizing, minimize the potential for chemical reactions with urine constituents to produce volatile, airborne contaminants such as cyanogen chloride. Additionally, the biocides are active under significantly less acidic conditions than those used in the current system, thereby reducing the degree of required acidification. A simple flow-through solid phase acidification (SPA) bed is employed to overcome the natural buffering
Jordan algebraic approach to symmetric optimization
Vieira, M.V.C.
2007-01-01
In this thesis we present a generalization of interior-point methods for linear optimization based on kernel functions to symmetric optimization. It covers the three standard cases of conic optimization: linear optimization, second-order cone optimization and semi-definite optimization. We give an
Real-Time Optimization for Economic Model Predictive Control
Sokoler, Leo Emil; Edlund, Kristian; Frison, Gianluca
2012-01-01
In this paper, we develop an efficient homogeneous and self-dual interior-point method for the linear programs arising in economic model predictive control. To exploit structure in the optimization problems, the algorithm employs a highly specialized Riccati iteration procedure. Simulations show...
Surface Reconstruction and Image Enhancement via $L^1$-Minimization
Dobrev, Veselin
2010-01-01
A surface reconstruction technique based on minimization of the total variation of the gradient is introduced. Convergence of the method is established, and an interior-point algorithm solving the associated linear programming problem is introduced. The reconstruction algorithm is illustrated on various test cases including natural and urban terrain data, and enhancement oflow-resolution or aliased images. Copyright © by SIAM.
Lauritzen, Niels
-Motzkin elimination, the theory is developed by introducing polyhedra, the double description method and the simplex algorithm, closed convex subsets, convex functions of one and several variables ending with a chapter on convex optimization with the Karush-Kuhn-Tucker conditions, duality and an interior point...
A SUCCESSIVE QUADRATIC PROGRAMMING ALGORITHM FOR SDP RELAXATION OF MAX-BISECTION
无
2007-01-01
A successive quadratic programming algorithm for solving SDP relaxation of MaxBisection is provided and its convergence result is given. The step-size in the algorithm is obtained by solving n easy quadratic equations without using the linear search technique. The numerical experiments show that this algorithm is rather faster than the interior-point method.
Developments in Surrogating Methods
Hans van Dormolen
2005-11-01
Full Text Available In this paper, I would like to talk about the developments in surrogating methods for preservation. My main focus will be on the technical aspects of preservation surrogates. This means that I will tell you something about my job as Quality Manager Microfilming for the Netherlands’ national preservation program, Metamorfoze, which is coordinated by the National Library. I am responsible for the quality of the preservation microfilms, which are produced for Metamorfoze. Firstly, I will elaborate on developments in preservation methods in relation to the following subjects: · Preservation microfilms · Scanning of preservation microfilms · Preservation scanning · Computer Output Microfilm. In the closing paragraphs of this paper, I would like to tell you something about the methylene blue test. This is an important test for long-term storage of preservation microfilms. Also, I will give you a brief report on the Cellulose Acetate Microfilm Conference that was held in the British Library in London, May 2005.
Motor degradation prediction methods
Arnold, J.R.; Kelly, J.F.; Delzingaro, M.J.
1996-12-01
Motor Operated Valve (MOV) squirrel cage AC motor rotors are susceptible to degradation under certain conditions. Premature failure can result due to high humidity/temperature environments, high running load conditions, extended periods at locked rotor conditions (i.e. > 15 seconds) or exceeding the motor`s duty cycle by frequent starts or multiple valve stroking. Exposure to high heat and moisture due to packing leaks, pressure seal ring leakage or other causes can significantly accelerate the degradation. ComEd and Liberty Technologies have worked together to provide and validate a non-intrusive method using motor power diagnostics to evaluate MOV rotor condition and predict failure. These techniques have provided a quick, low radiation dose method to evaluate inaccessible motors, identify degradation and allow scheduled replacement of motors prior to catastrophic failures.
CarloAlberto Redi
2010-06-01
Full Text Available Mitosis Methods & Protocols Andrew D. McAinsh (Edt Humana press, Totowa, New Jersey (USA Series: Springer Protocols Methods in Molecular Biology, Volume 545, 2009 ISBN: 978-1-60327-992-5 It is quite clear from the contents of this book that the remarkably fascinating phenomenon of mitosis (that captured, and still is capturing, the attention of entire generations of scientists is still open to research. This is mainly due to our lack of knowledge of so many multifaced events of this extraordinarly complex process. The reader giving a glace through the Contents and Contributors sections is speechless: All of the first-class models (i.e., budding yeast, Caenorabditis, Drosophila, Xenopus and Human are presented.....
Wölfel, Christiane; Merritt, T.
2013-01-01
. The card-based tools are explained in terms of five design dimensions including the intended purpose and scope of use, duration of use, methodology, customization, and formal/material qualities. Our analysis suggests three design patterns or archetypes for existing card-based design method tools...... and highlights unexplored areas in the design space. The paper concludes with recommendations for the future development of card-based methods for the field of interaction design.......There are many examples of cards used to assist or provide structure to the design process, yet there has not been a thorough articulation of the strengths and weaknesses of the various examples. We review eighteen card-based design tools in order to understand how they might benefit designers...
Holm, Darryl D
2015-01-01
Vortex blob methods are typically characterized by a regularization length scale, below which the the dynamics are trivial for isolated blobs. In this article we will find that the dynamics need not be trivial if one is willing to consider distributional derivatives of Dirac delta functionals as valid vorticity distributions. More specifically, a new singular vortex theory is presented for regularised Euler fluid equations of ideal incompressible flow in the plane. We determine the conditions under which such regularised Euler fluid equations may admit vorticity singularities which are stronger than delta functions, e.g., derivatives of delta functions. We also characterise the Hamiltonian dynamics of the higher-order singular vortices. Applications to the design of numerical meth- ods similar to vortex blob methods are also discussed. Such findings shed light onto the rich dynamics which occur below the regularization length scale and enlighten our perspective on the multiscale aspects of regularized fluid m...
Cathleen Haskins
2010-06-01
Full Text Available Dr. Maria Montessori provided the world with a powerful philosophy and practice for the advancement of humanity: change how we educate children and we change the world. She understood two things very clearly: One, that we can build a better world, a more just and peaceful place, when we educate for the realization of the individual and collective human potential; and two, that the only way to create an educational system that will that will serve this end is to scrap the current system entirely and replace it with a completely new system. She gave us a system through which to accomplish that goal: The Montessori Method. The following is a personal and professional account of the Montessori Method of educating children.
Fong-Zhi Chen
2001-01-01
Full Text Available In this study, the Plücker coordinates representation is used to formulate the ruled surface and the molecular path for pumping speed performance evaluation of a molecular vacuum pump. The ruled surface represented by the Pliicker coordinates is used to develop a criterion for when gas molecules hit the pump surface wall. The criterion is applied to analyze the flow rate of a new developed vacuum pump in transition regimes by using the DSMC (Direct Simulation Monte Carlo method. When a molecule flies in a neutral electrical field its path is a straight line. If the molecular path and the generators of a ruled surface are both represented by the Pliicker coordinates, the position of the molecular hit on the wall can be verified by the reciprocal condition of the lines. The Plücker coordinates representation is quite convenient in the DSMC method for this three-dimensional molecular flow simulation.
Anthropological methods in ethnopharmacology.
Etkin, N L
1993-03-01
This paper reviews anthropological methods in ethnopharmacology to advance a critical and biobehavioral perspective for the construction of primary data in the light of indigenous paradigms of health and therapeutics. The unique contributions of anthropology are the conceptual and practical tools that allow one to develop the ethnography of plant use in sufficient depth to correlate with laboratory and clinical investigations of plant constituents and activities. This serves an ethnopharmacology that links bioscientific research to traditional empirical knowledge. Specific methods discussed include: key respondents, participant observation, focus groups, structured and unstructured interviews, survey instruments and questionnaires, lexical and semantic studies, and discourse and content analysis. The accommodation of rapid ethnographic techniques for ethnopharmacologic research is described, and several problem orientations based on assessments of efficacy are offered.
Roxana L. IONESCU
2014-06-01
Full Text Available Companies operating in a global economy that is constantly changing and developming, especially during the financial crisis and political instability. It is necessary to adapt and develop sales methods in such environment. For large companies who base their activity on sales it has become a necessity to learn different types of sales approaches because their knowledge enables them to grow the number of customers and therefore the sales and the turnover. This paper aims to exame the most effective sales methods used on the highly sensitive economic and social environment – the insurance market. In the field of insurances, the sales process is even more important because sellers need to sell an intangible product that may materialize in the future, but there is no certainty.
2013-01-01
Disclosed is a method of transmitting a data set using encryption, wherein the method comprises the steps of: selecting a first encryption technique, wherein said first encryption technique comprises a first encryption algorithm for encrypting plain data into cipher data, and a first decryption...... algorithm for on provision of a specific key, decrypting cipher data and reproduce plain data; encrypting the first data package comprising plain data, using a first encryption program implementing the first encryption algorithm of said first encryption technique, creating a first encrypted data package...... comprising cipher data; obtaining a first decryption program; and transmitting said first decryption program and said first encrypted data package to a receiver, wherein the first decryption, upon provision of the specific key and the first encrypted data package, will decrypt the cipher data in the first...
Horia Dumitrescu
1998-01-01
Full Text Available The vortex model of propellers is modified and applied to the high-speed horizontal axis turbines. The turbine blades are replaced by lifting lines and trailing vortices which shed along the blade span. The model is not a free wake model, but it is still a nonlinear one which should be solved iteratively. In addition to the regular case where the trailing vortices are constrained to distribute along a helical surface, another version, where each trailing vortex sheding from the blade grows as a free helical vortex line, is also included. Performance parameters are calculated by application of the Biot-Savart law along with the Kutta-Joukowski theorem. Predictions are, shown to compare favorably with existing numerical data from more involved free wake methods, but require less computational effort. Thereby, the present method may be a very useful tool for calculating the aerodynamic loads on horizontal-axis wind turbine blades.
Petre GEORGIEVSKI
1999-05-01
Full Text Available The effort in this work to elaborate an action research method as a central research problem considering the recent contemporary sociological and educational literature. The author begins with the statement that the method is a complex notion, composed of three main components: approach to the research problem, data gathering procedures and data analysis procedures. This point of view is further applied and elaborated in the author's text, emphasizing the action research characteristics: interruption with the positive tradition in social research and the divided of the objective and subjective, application of the qualitative data. The substantial difference between the action research in regard with the other kinds of research, is not only in getting to new knowledge's, but also in problem solving or a change in the situation in a concrete social context.
Nanoscale waveguiding methods.
Wang, Chia-Jean; Lin, Lih Y
2007-05-01
While 32 nm lithography technology is on the horizon for integrated circuit (IC) fabrication, matching the pace for miniaturization with optics has been hampered by the diffraction limit. However, development of nanoscale components and guiding methods is burgeoning through advances in fabrication techniques and materials processing. As waveguiding presents the fundamental issue and cornerstone for ultra-high density photonic ICs, we examine the current state of methods in the field. Namely, plasmonic, metal slot and negative dielectric based waveguides as well as a few sub-micrometer techniques such as nanoribbons, high-index contrast and photonic crystals waveguides are investigated in terms of construction, transmission, and limitations. Furthermore, we discuss in detail quantum dot (QD) arrays as a gain-enabled and flexible means to transmit energy through straight paths and sharp bends. Modeling, fabrication and test results are provided and show that the QD waveguide may be effective as an alternate means to transfer light on sub-diffraction dimensions.
Fox, Robert V.; Zhang, Fengyan; Rodriguez, Rene G.; Pak, Joshua J.; Sun, Chivin
2016-06-21
Single source precursors or pre-copolymers of single source precursors are subjected to microwave radiation to form particles of a I-III-VI.sub.2 material. Such particles may be formed in a wurtzite phase and may be converted to a chalcopyrite phase by, for example, exposure to heat. The particles in the wurtzite phase may have a substantially hexagonal shape that enables stacking into ordered layers. The particles in the wurtzite phase may be mixed with particles in the chalcopyrite phase (i.e., chalcopyrite nanoparticles) that may fill voids within the ordered layers of the particles in the wurtzite phase thus produce films with good coverage. In some embodiments, the methods are used to form layers of semiconductor materials comprising a I-III-VI.sub.2 material. Devices such as, for example, thin-film solar cells may be fabricated using such methods.
Fox, Robert V.; Zhang, Fengyan; Rodriguez, Rene G.; Pak, Joshua J.; Sun, Chivin
2016-06-21
Single source precursors or pre-copolymers of single source precursors are subjected to microwave radiation to form particles of a I-III-VI.sub.2 material. Such particles may be formed in a wurtzite phase and may be converted to a chalcopyrite phase by, for example, exposure to heat. The particles in the wurtzite phase may have a substantially hexagonal shape that enables stacking into ordered layers. The particles in the wurtzite phase may be mixed with particles in the chalcopyrite phase (i.e., chalcopyrite nanoparticles) that may fill voids within the ordered layers of the particles in the wurtzite phase thus produce films with good coverage. In some embodiments, the methods are used to form layers of semiconductor materials comprising a I-III-VI.sub.2 material. Devices such as, for example, thin-film solar cells may be fabricated using such methods.
Vempala, Santosh S
2005-01-01
Random projection is a simple geometric technique for reducing the dimensionality of a set of points in Euclidean space while preserving pairwise distances approximately. The technique plays a key role in several breakthrough developments in the field of algorithms. In other cases, it provides elegant alternative proofs. The book begins with an elementary description of the technique and its basic properties. Then it develops the method in the context of applications, which are divided into three groups. The first group consists of combinatorial optimization problems such as maxcut, graph coloring, minimum multicut, graph bandwidth and VLSI layout. Presented in this context is the theory of Euclidean embeddings of graphs. The next group is machine learning problems, specifically, learning intersections of halfspaces and learning large margin hypotheses. The projection method is further refined for the latter application. The last set consists of problems inspired by information retrieval, namely, nearest neig...
Bertozzi, Carolyn C. (Albany, CA); Yarema, Kevin J. (Albany, CA); Mahal; Lara K. (Berkeley, CA)
2008-04-01
Methods for making the functionalized glycoconjugates include (a) contacting a cell with a first monosaccharide, and (b) incubating the cell under conditions whereby the cell (i) internalizes the first monosaccharide, (ii) biochemically processes the first monosaccharide into a second saccharide, (iii) conjugates the saccharide to a carrier to form a glycoconjugate, and (iv) extracellularly expresses the glycoconjugate to form an extracellular glycoconjugate comprising a selectively reactive functional group. Methods for forming products at a cell further comprise contacting the functional group of the extracellularly expressed glycoconjugate with an agent which selectively reacts with the functional group to form a product. Subject compositions include cyto-compatible monosaccharides comprising a nitrogen or ether linked functional group selectively reactive at a cell surface and compositions and cells comprising such saccharides.
Statistical Methods for Astronomy
Feigelson, Eric D
2012-01-01
This review outlines concepts of mathematical statistics, elements of probability theory, hypothesis tests and point estimation for use in the analysis of modern astronomical data. Least squares, maximum likelihood, and Bayesian approaches to statistical inference are treated. Resampling methods, particularly the bootstrap, provide valuable procedures when distributions functions of statistics are not known. Several approaches to model selection and good- ness of fit are considered. Applied statistics relevant to astronomical research are briefly discussed: nonparametric methods for use when little is known about the behavior of the astronomical populations or processes; data smoothing with kernel density estimation and nonparametric regression; unsupervised clustering and supervised classification procedures for multivariate problems; survival analysis for astronomical datasets with nondetections; time- and frequency-domain times series analysis for light curves; and spatial statistics to interpret the spati...
Masrizal Masrizal
2012-03-01
Full Text Available Mixed Method Research adalah metode penelitian yang diaplikasikan bila peneliti memiliki pertanyaan yang perlu diuji dari segi outcomes dan prosesnya, serta menyangkut kombinasi antara metode kuantitatif dan kualitatif dalam satu penelitian. Karena berfokus pada outcomes dan proses, maka desain MMR biasa digunakan dalam penelitian evaluasi program. Namun sekarang, MMR sudah sering digunakan untuk ilmu-ilmu sosial, seperti: konseling, psikologi social manajemen, dan pengorganisasian perilaku.
Masrizal Masrizal
2012-01-01
Mixed Method Research adalah metode penelitian yang diaplikasikan bila peneliti memiliki pertanyaan yang perlu diuji dari segi outcomes dan prosesnya, serta menyangkut kombinasi antara metode kuantitatif dan kualitatif dalam satu penelitian. Karena berfokus pada outcomes dan proses, maka desain MMR biasa digunakan dalam penelitian evaluasi program. Namun sekarang, MMR sudah sering digunakan untuk ilmu-ilmu sosial, seperti: konseling, psikologi social manajemen, dan pengorganisasian perilaku.
Chang, Shih-ger; Liu, Shou-heng; Liu, Zhao-rong; Yan, Naiqiang
2009-01-20
Disclosed herein is a method for removing mercury from a gas stream comprising contacting the gas stream with a getter composition comprising bromine, bromochloride, sulphur bromide, sulphur dichloride or sulphur monochloride and mixtures thereof. In one preferred embodiment the getter composition is adsorbed onto a sorbent. The sorbent may be selected from the group consisting of flyash, limestone, lime, calcium sulphate, calcium sulfite, activated carbon, charcoal, silicate, alumina and mixtures thereof. Preferred is flyash, activated carbon and silica.
Statokinesigram normalization method.
de Oliveira, José Magalhães
2017-02-01
Stabilometry is a technique that aims to study the body sway of human subjects, employing a force platform. The signal obtained from this technique refers to the position of the foot base ground-reaction vector, known as the center of pressure (CoP). The parameters calculated from the signal are used to quantify the displacement of the CoP over time; there is a large variability, both between and within subjects, which prevents the definition of normative values. The intersubject variability is related to differences between subjects in terms of their anthropometry, in conjunction with their muscle activation patterns (biomechanics); and the intrasubject variability can be caused by a learning effect or fatigue. Age and foot placement on the platform are also known to influence variability. Normalization is the main method used to decrease this variability and to bring distributions of adjusted values into alignment. In 1996, O'Malley proposed three normalization techniques to eliminate the effect of age and anthropometric factors from temporal-distance parameters of gait. These techniques were adopted to normalize the stabilometric signal by some authors. This paper proposes a new method of normalization of stabilometric signals to be applied in balance studies. The method was applied to a data set collected in a previous study, and the results of normalized and nonnormalized signals were compared. The results showed that the new method, if used in a well-designed experiment, can eliminate undesirable correlations between the analyzed parameters and the subjects' characteristics and show only the experimental conditions' effects.
Chen, J.-Y.
1992-01-01
Viewgraphs are presented on the following topics: the grand challenge of combustion engineering; research of probability density function (PDF) methods at Sandia; experiments of turbulent jet flames (Masri and Dibble, 1988); departures from chemical equilibrium; modeling turbulent reacting flows; superequilibrium OH radical; pdf modeling of turbulent jet flames; scatter plot for CH4 (methane) and O2 (oxygen); methanol turbulent jet flames; comparisons between predictions and experimental data; and turbulent C2H4 jet flames.
Situational method engineering
Henderson-Sellers, Brian; Ågerfalk, Pär J; Rossi, Matti
2014-01-01
While previously available methodologies for software ? like those published in the early days of object technology ? claimed to be appropriate for every conceivable project, situational method engineering (SME) acknowledges that most projects typically have individual characteristics and situations. Thus, finding the most effective methodology for a particular project needs specific tailoring to that situation. Such a tailored software development methodology needs to take into account all the bits and pieces needed for an organization to develop software, including the software process, the
Polymer compositions and methods
Allen, Scott D.; Willkomm, Wayne R.
2016-09-27
The present invention encompasses polyurethane compositions comprising aliphatic polycarbonate chains. In one aspect, the present invention encompasses polyurethane foams, thermoplastics and elastomers derived from aliphatic polycarbonate polyols and polyisocyanates wherein the polyol chains contain a primary repeating unit having a structure: ##STR00001## In another aspect, the invention provides articles comprising the inventive foam and elastomer compositions as well as methods of making such compositions.
Nearshore Pipeline Installation Methods.
1981-08-01
179. 5. Aldridge, R. G., and Bomba , J. G., "Deep Water Pipelines - Interdependence of Design and Construction", ASCE Paper. 6. American Society Civil...October 13, 1967. 24. Bomba , J. G. and Seeds, K. J., "Pipelining in 600 feet of water .... A Case Study of Washington Natural Gas Company’s Puget Sound...Crossing", Offshore Technology Conference, paper OTC 1188, 1970. 25. Bomba , J., "Submarine Pipe Construction Methods", Petroleum Engineer, Vol. 32
Rege, Kaushal
2009-01-01
Filling a critical gap in the current literature, this new resource presents practical, step-by-step methods to help you synthesize, characterize, biofunctionalize and apply the nanomaterial that is most suitable for handling a given nanoscale bioengineering problem. Written and presented by leading scientists and engineers in their respective fields, the authors offer a clear and detailed understanding of how to carry out nanoparticle functionalization with biomolecules (including enzymes), nanoparticle analysis and characterization, in vitro evaluation of nanoparticles using different cell l
Chang-Diaz, Franklin R. (Inventor)
1989-01-01
Apparatus and method of removing desirable constituents from an infusible material by infusion extraction, where a piston operating in a first chamber draws a solvent into the first chamber where it may be heated, and then moves the heated solvent into a second chamber containing the infusible material, and where infusion extraction takes place. The piston then moves the solvent containing the extract through a filter into the first chamber, leaving the extraction residue in the second chamber.
Method for detecting biomolecules
Huo, Qisheng; Liu, Jun
2008-08-12
A method for detecting and measuring the concentration of biomolecules in solution, utilizing a conducting electrode in contact with a solution containing target biomolecules, with a film with controllable pore size distribution characteristics applied to at least one surface of the conducting electrode. The film is functionalized with probe molecules that chemically interact with the target biomolecules at the film surface, blocking indicator molecules present in solution from diffusing from the solution to the electrode, thereby changing the electrochemical response of the electrode
Chang, Shih-ger; Liu, Shou-heng; Liu, Zhao-rong; Yan, Naiqiang
2010-07-13
Disclosed herein is a method for removing mercury from a gas stream comprising contacting the gas stream with a getter composition comprising bromine, bromochloride, sulphur bromide, sulphur dichloride or sulphur monochloride and mixtures thereof. In one preferred embodiment the getter composition is adsorbed onto a sorbent. The sorbent may be selected from the group consisting flyash, limestone, lime, calcium sulphate, calcium sulfite, activated carbon, charcoal, silicate, alumina and mixtures thereof. Preferred is flyash, activated carbon and silica.
Sithambaram, Shanthakumar; Son, Young-Chan; Suib, Steven L.
2008-04-08
A method for forming an imine comprises reacting a first reactant comprising a hydroxyl functionality, a carbonyl functionality, or both a hydroxyl functionality and a carbonyl functionality with a second reactant having an amine functionality in the presence of ordered porous manganese-based octahedral molecular sieves and an oxygen containing gas at a temperature and for a time sufficient for the imine to be produced.
Zahn, Jeffrey D
2009-01-01
This unique volume presents leading-edge microfluidics methods used to handle, manipulate, and analyze cells, particles, and biological components (e.g., proteins and DNA) for microdiagnostics. The authors offer clear and detailed guidance on microfabrication techniques utilized to create microfluidic devices and on-chip flow control and mixing Microsystems, protein and DNA handling devices for electrophoretic and isoelectric separations in microchromatography columns, microfluidic manipulations of droplets via electrowetting and particles via dielectrophoresis for separations and chemical rea
Kato, Akio
2006-11-14
The invention provides methods for chromosome doubling in plants. The technique overcomes the low yields of doubled progeny associated with the use of prior techniques for doubling chromosomes in plants such as grasses. The technique can be used in large scale applications and has been demonstrated to be highly effective in maize. Following treatment in accordance with the invention, plants remain amenable to self fertilization, thereby allowing the efficient isolation of doubled progeny plants.
Athanasios Drigas; Eugenia Gkeka
2016-01-01
This article bridges the gap between the Montessori Method and Information and Communication Technologies (ICTs) in contemporary education. It reviews recent research works which recall the Montessori philosophy, principles and didactical tools applying to today’s computers and supporting technologies in children’s learning process. This article reviews how important the stimulation of human senses in the learning process is, as well as the development of Montessori materials using the body a...
Geometrical method of decoupling
Baumgarten, C.
2012-12-01
The computation of tunes and matched beam distributions are essential steps in the analysis of circular accelerators. If certain symmetries—like midplane symmetry—are present, then it is possible to treat the betatron motion in the horizontal, the vertical plane, and (under certain circumstances) the longitudinal motion separately using the well-known Courant-Snyder theory, or to apply transformations that have been described previously as, for instance, the method of Teng and Edwards. In a preceding paper, it has been shown that this method requires a modification for the treatment of isochronous cyclotrons with non-negligible space charge forces. Unfortunately, the modification was numerically not as stable as desired and it was still unclear, if the extension would work for all conceivable cases. Hence, a systematic derivation of a more general treatment seemed advisable. In a second paper, the author suggested the use of real Dirac matrices as basic tools for coupled linear optics and gave a straightforward recipe to decouple positive definite Hamiltonians with imaginary eigenvalues. In this article this method is generalized and simplified in order to formulate a straightforward method to decouple Hamiltonian matrices with eigenvalues on the real and the imaginary axis. The decoupling of symplectic matrices which are exponentials of such Hamiltonian matrices can be deduced from this in a few steps. It is shown that this algebraic decoupling is closely related to a geometric “decoupling” by the orthogonalization of the vectors E→, B→, and P→, which were introduced with the so-called “electromechanical equivalence.” A mathematical analysis of the problem can be traced down to the task of finding a structure-preserving block diagonalization of symplectic or Hamiltonian matrices. Structure preservation means in this context that the (sequence of) transformations must be symplectic and hence canonical. When used iteratively, the decoupling
Electron cryomicroscopy methods.
Unger, V M
2001-10-01
Electron cryomicroscopy methods comprise a rapidly expanding field providing insights into the structure and function of biological macromolecules and their supramolecular assemblies. The 3.8 A resolution structure of the membrane protein aquaporin, a view of the herpesvirus capsid at 8.5 A and the 10 A resolution structure of the spliceosomal U1 small nuclear ribonucleoprotein complex are three outstanding examples emphasizing the versatility of this technique.
Method for making nanomaterials
Fan, Hongyou; Wu, Huimeng
2013-06-04
A method of making a nanostructure by preparing a face centered cubic-ordered metal nanoparticle film from metal nanoparticles, such as gold and silver nanoparticles, exerting a hydrostatic pressure upon the film at pressures of several gigapascals, followed by applying a non-hydrostatic stress perpendicularly at a pressure greater than approximately 10 GPA to form an array of nanowires with individual nanowires having a relatively uniform length, average diameter and density.
Bering Mission Navigation Method
2003-01-01
"Bering", after the name of the famous Danish explorer, is a near Earth object (NEO) and main belt asteroids mapping mission envisaged by a consortium of Danish universities and research institutes. To achieve the ambitious goals set forth by this mission, while containing the costs and risks, "Bering" sports several new technological enhancements and advanced instruments under development at the Technical University of Denmark (DTU). The autonomous on-board orbit determination method is part...
Methods of celestial mechanics
Brouwer, Dirk
2013-01-01
Methods of Celestial Mechanics provides a comprehensive background of celestial mechanics for practical applications. Celestial mechanics is the branch of astronomy that is devoted to the motions of celestial bodies. This book is composed of 17 chapters, and begins with the concept of elliptic motion and its expansion. The subsequent chapters are devoted to other aspects of celestial mechanics, including gravity, numerical integration of orbit, stellar aberration, lunar theory, and celestial coordinates. Considerable chapters explore the principles and application of various mathematical metho
ARK methods: some recent developments
Moir, Nicolette
2005-03-01
Almost Runge-Kutta methods are a sub-class of the family of methods known as general linear methods, used for solving ordinary differential equations. They combine many of the favourable properties of traditional Runge-Kutta methods with some additional advantages. We will introduce these methods, concentrating on methods of order four, and present some recent results.
Trottenberg, U; Third European Conference on Multigrid Methods
1991-01-01
These proceedings contain a selection of papers presented at the Third European Conference on Multigrid Methods which was held in Bonn on October 1-4, 1990. Following conferences in 1981 and 1985, a platform for the presentation of new Multigrid results was provided for a third time. Multigrid methods no longer have problems being accepted by numerical analysts and users of numerical methods; on the contrary, they have been further developed in such a successful way that they have penetrated a variety of new fields of application. The high number of 154 participants from 18 countries and 76 presented papers show the need to continue the series of the European Multigrid Conferences. The papers of this volume give a survey on the current Multigrid situation; in particular, they correspond to those fields where new developments can be observed. For example, se veral papers study the appropriate treatment of time dependent problems. Improvements can also be noticed in the Multigrid approach for semiconductor eq...
Kallianpur, Gopinath; Hida, Takeyuki
1987-01-01
The use of probabilistic methods in the biological sciences has been so well established by now that mathematical biology is regarded by many as a distinct dis cipline with its own repertoire of techniques. The purpose of the Workshop on sto chastic methods in biology held at Nagoya University during the week of July 8-12, 1985, was to enable biologists and probabilists from Japan and the U. S. to discuss the latest developments in their respective fields and to exchange ideas on the ap plicability of the more recent developments in stochastic process theory to problems in biology. Eighteen papers were presented at the Workshop and have been grouped under the following headings: I. Population genetics (five papers) II. Measure valued diffusion processes related to population genetics (three papers) III. Neurophysiology (two papers) IV. Fluctuation in living cells (two papers) V. Mathematical methods related to other problems in biology, epidemiology, population dynamics, etc. (six papers) An important f...
Validation of analytical methods
Xavier Rius, F.
2002-03-01
Full Text Available In this paper we shall discuss the concept of method validation, describe the various elements and explain its close relationship with fitness for purpose. Method validation is based on the assumption that a series of requirements are fulfilled and we shall explain how these requirements are selected, the way in which evidence is supplied and what work has to be carried out in the laboratory. The basic principles of method validation and the different ways to validate a methodology, by inter-laboratory comparison or performing an in-house validation, are also described.En este artículo se discute el concepto de validación del método, se describen los elementos que la componen y se explica la fuerte relación entre la validación y las características de ajuste. El método de validación se basa en el cumplimiento de una serie de requerimientos, se explica como seleccionar esos requerimientos, la forma en que se suministran evidencias, y que trabajo se debe llevar a cabo en el laboratorio. También se describen, los principios básicos del método de validación y los diferentes caminos para validar una metodología, tanto en la comparación entre laboratorios o como cuando se lleva a cabo una validación dentro del laboratorio.
Generalized Agile Estimation Method
Shilpa Bahlerao
2011-01-01
Full Text Available Agile cost estimation process always possesses research prospects due to lack of algorithmic approaches for estimating cost, size and duration. Existing algorithmic approach i.e. Constructive Agile Estimation Algorithm (CAEA is an iterative estimation method that incorporates various vital factors affecting the estimates of the project. This method has lots of advantages but at the same time has some limitations also. These limitations may due to some factors such as number of vital factors and uncertainty involved in agile projects etc. However, a generalized agile estimation may generate realistic estimates and eliminates the need of experts. In this paper, we have proposed iterative Generalized Estimation Method (GEM and presented algorithm based on it for agile with case studies. GEM based algorithm various project domain classes and vital factors with prioritization level. Further, it incorporates uncertainty factor to quantify the risk of project for estimating cost, size and duration. It also provides flexibility to project managers for deciding on number of vital factors, uncertainty level and project domains thereby maintaining the agility.
Method Engineering: Engineering of Information Systems Development Methods and Tools
Brinkkemper, J.N.; Brinkkemper, Sjaak
1996-01-01
This paper proposes the term method engineering for the research field of the construction of information systems development methods and tools. Some research issues in method engineering are identified. One major research topic in method engineering is discussed in depth: situational methods, i.e.
Sandford, M.T. II; Bradley, J.N.; Handel, T.G.
1996-06-01
Data embedding is a new steganographic method for combining digital information sets. This paper describes the data embedding method and gives examples of its application using software written in the C-programming language. Sandford and Handel produced a computer program (BMPEMBED, Ver. 1.51 written for IBM PC/AT or compatible, MS/DOS Ver. 3.3 or later) that implements data embedding in an application for digital imagery. Information is embedded into, and extracted from, Truecolor or color-pallet images in Microsoft{reg_sign} bitmap (.BMP) format. Hiding data in the noise component of a host, by means of an algorithm that modifies or replaces the noise bits, is termed {open_quote}steganography.{close_quote} Data embedding differs markedly from conventional steganography, because it uses the noise component of the host to insert information with few or no modifications to the host data values or their statistical properties. Consequently, the entropy of the host data is affected little by using data embedding to add information. The data embedding method applies to host data compressed with transform, or {open_quote}lossy{close_quote} compression algorithms, as for example ones based on discrete cosine transform and wavelet functions. Analysis of the host noise generates a key required for embedding and extracting the auxiliary data from the combined data. The key is stored easily in the combined data. Images without the key cannot be processed to extract the embedded information. To provide security for the embedded data, one can remove the key from the combined data and manage it separately. The image key can be encrypted and stored in the combined data or transmitted separately as a ciphertext much smaller in size than the embedded data. The key size is typically ten to one-hundred bytes, and it is in data an analysis algorithm.
Sandford, Maxwell T., II; Bradley, Jonathan N.; Handel, Theodore G.
1996-01-01
Data embedding is a new steganographic method for combining digital information sets. This paper describes the data embedding method and gives examples of its application using software written in the C-programming language. Sandford and Handel produced a computer program (BMPEMBED, Ver. 1.51 written for IBM PC/AT or compatible, MS/DOS Ver. 3.3 or later) that implements data embedding in an application for digital imagery. Information is embedded into, and extracted from, Truecolor or color-pallet images in MicrosoftTM bitmap (BMP) format. Hiding data in the noise component of a host, by means of an algorithm that modifies or replaces the noise bits, is termed `steganography.' Data embedding differs markedly from conventional steganography, because it uses the noise component of the host to insert information with few or no modifications to the host data values or their statistical properties. Consequently, the entropy of the host data is affected little by using data embedding to add information. The data embedding method applies to host data compressed with transform, or `lossy' compression algorithms, as for example ones based on discrete cosine transform and wavelet functions. Analysis of the host noise generates a key required for embedding and extracting the auxiliary data from the combined data. The key is stored easily in the combined data. Images without the key cannot be processed to extract the embedded information. To provide security for the embedded data, one can remove the key from the combined data and manage it separately. The image key can be encrypted and stored in the combined data or transmitted separately as a ciphertext much smaller in size than the embedded data. The key size is typically ten to one-hundred bytes, and it is derived from the original host data by an analysis algorithm.
ZIRCONIUM PHOSPHATE ADSORPTION METHOD
Russell, E.R.; Adamson, A.S.; Schubert, J.; Boyd, G.E.
1958-11-01
A method is presented for separating plutonium values from fission product values in aqueous acidic solution. This is accomplished by flowing the solutlon containing such values through a bed of zirconium orthophosphate. Any fission products adsorbed can subsequently be eluted by washing the column with a solution of 2N HNO/sub 3/ and O.lN H/sub 3/PO/sub 4/. Plutonium values may subsequently be desorbed by contacting the column with a solution of 7N HNO/sub 3/ .
Nastasescu, Constantin
2004-01-01
The topic of this book, graded algebra, has developed in the past decade to a vast subject with new applications in noncommutative geometry and physics. Classical aspects relating to group actions and gradings have been complemented by new insights stemming from Hopf algebra theory. Old and new methods are presented in full detail and in a self-contained way. Graduate students as well as researchers in algebra, geometry, will find in this book a useful toolbox. Exercises, with hints for solution, provide a direct link to recent research publications. The book is suitable for courses on Master level or textbook for seminars.