检索结果-内蒙古大学图书馆

Beyond Max-Cut: λ-extendible properties parameterized above the Poljak-Turzik bound

JOURNAL OF COMPUTER AND SYSTEM SCIENCES 2014年第7期80卷 1384-1403页

作者： Mnich, Matthias Philip, Geevarghese Saurabh, Saket Suchy, Ondrej Max Planck Inst Informat D-66123 Saarbrucken Germany Inst Math Sci Chennai 600113 Tamil Nadu India Czech Tech Univ CR-16635 Prague Czech Republic

We define strong lambda-extendibility as a variant of the notion of lambda-extendible properties of graphs (Poljak and Turzik, Discrete Mathematics, 1986). We show that the parameterized APT(Pi) problem - given a connected graph G on n vertices and m edges and an integer parameter k, does there exist a spanning subgraph H of G such that H is an element of Pi and H has at least [GRAPHICS] edges - is fixed-parameter tractable (FPT) for all 0 < lambda < 1, for all strongly lambda-extendible graph properties Pi for which the APT(Pi) problem is FPT on graphs which are 0(k) vertices away from being a graph in which each block is a clique. Our results hold for properties of oriented graphs and graphs with edge labels, generalize the recent result of Crowston et al. (ICALP 2012) on MAX-CUT parameterized above the Edwards-Erdos bound, and yield FPT algorithms for several graph problems parameterized above lower bounds. (C) 2014 Elsevier Inc. All rights reserved.

关键词： algorithms and data structures Fixed-parameter tractable algorithms Above-guarantee parameterization MAX-CUT lambda-extendible properties

来源：评论

学校读者我要写书评

暂无评论

The Epoch-State Filter, Revisited

引用

JOURNAL OF GUIDANCE CONTROL AND DYNAMICS 2023年第7期46卷 1228-1242页

作者： Carpenter, J. Russell NASA Goddard Space Flight Ctr Space Sci Mission Operat Tech Code 444 Greenbelt MD 20771 USA

The epoch-state filter is a recursive sequential estimator that maintains its state estimate and associated covariance at a fixed time known as the epoch, avoiding the need to propagate the covariance between measurements. Instead, the filter maps measurement innovations from the measurement time to the epoch time, in a fashion similar to a batch estimator. When process noise is present, the epoch time must follow all but at most the penultimate measurement. Revisiting the topic, this paper contributes several variations, including a factorized form, a factorized information form, and sigma-point versions, and provides a number of clarifying illustrative examples.

关键词： Kalman Filter algorithms and data structures Mathematical Analysis Celestial Mechanics Satellites Computing and Informatics Navigation Algorithm

来源：评论

学校读者我要写书评

暂无评论

Restricted rotation distance between binary trees

引用

INFORMATION PROCESSING LETTERS 2002年第6期84卷 333-338页

作者： Cleary, S CUNY City Coll Dept Math New York NY 10031 USA

Restricted rotation distance between pairs of rooted binary trees measures differences in tree shape and is related to rotation distance. hi restricted rotation distance, the rotations used to transform the trees are allowed to be only of two types. Restricted rotation distance is larger than rotation distance, since there are only two permissible locations to rotate, but is much easier to compute and estimate. We obtain linear upper and lower bounds for restricted rotation distance in terms of the number of interior nodes in the trees. Further, we describe a linear-time algorithm for estimating the restricted rotation distance between two trees and for finding a sequence of rotations which realizes that estimate. The methods use the metric properties of the abstract group known as Thompson's group F. (C) 2002 Published by Elsevier Science B.V.

关键词： algorithms and data structures binary trees rotation distance

来源：评论

学校读者我要写书评

暂无评论

Polynomial Guidance for Impact-Time Control Against Maneuvering Targets

引用

JOURNAL OF GUIDANCE CONTROL AND DYNAMICS 2023年第12期46卷 2388-2398页

作者： Li, Haojian Liu, Yuanhe Li, Kebo Liang, Yan'gang Natl Univ Def Technol Coll Aerosp Sci & Engn Changsha 410072 Hunan Peoples R China

To address the issue of intercepting maneuvering targets at a specific time, a polynomial guidance method for impact-time control is proposed in this paper. Based on the relative virtual framework and the classical differential geometry curve theory, such method is divided into two parts: 1) the design of the relative trajectory-length-control (RTLC) guidance law against virtual stationary targets, and 2) the design of the prediction algorithms based on the guidance law or its characteristics. The former realizes RTLC, and the latter establishes the relationship between the desired relative trajectory length-to-go and the desired time-to-go, thus implementing impact-time control. Furthermore, based on the analytical properties of the guidance law in the relative arc-length domain, its performance, characteristics, and allowable impact time are analyzed. Finally, the effectiveness of the proposed guidance method and the validity of the theoretical findings are verified by numerical simulations results.

关键词： Guidance Navigation and Control Systems Prediction algorithms Numerical Simulation Spacecraft Guidance and Control Flight Path Angle Aerospace Sciences Proportional Navigation Missile Guidance and Control algorithms and data structures State Estimation

来源：评论

学校读者我要写书评

暂无评论

Extended skew partition problem

引用

DISCRETE MATHEMATICS 2006年第19-20期306卷 2438-2449页

作者： Dantas, Simone de Figueiredo, Celina M. H. Gravier, Sylvain Klein, Sulamita Univ Fed Rio de Janeiro COPPE BR-21941 Rio De Janeiro Brazil Univ Fed Rio de Janeiro Inst Matemat BR-21941 Rio De Janeiro Brazil CNRS Lab Leibniz F-75700 Paris France

A skew partition as defined by Chvatal is a partition of the vertex set of a graph into four nonempty parts A(1), A(2), B-1, B-2 such that there are all possible edges between A(1) and A(2), and no edges between B-1 and B-2. We introduce the concept of (n(1), n(2))-extended skew partition which includes all partitioning problems into n(1) + n(2) nonempty parts A(1),..., An(1), B-1,...,Bn-2, such that there are all possible edges between the A(i) parts, no edges between the B-j parts, i is an element of (1, ..., n(1)}, j is an element of {1,..., n(2)}, which generalizes the skew partition. We present a polynomial-time algorithm for testing whether a graph admits an (n(1), n(2))-extended skew partition. As a tool to complete this task we also develop a generalized 2-SAT algorithm, which by itself may have application to other partition problems. (c) 2006 Elsevier B.V. All rights reserved.

关键词： algorithms and data structures computational and structural complexity skew partition 2-SAT

来源：评论

学校读者我要写书评

暂无评论

Boosted Incremental Nonlinear Dynamic Inversion for Flexible Airplane Gust Load Alleviation

引用

JOURNAL OF GUIDANCE CONTROL AND DYNAMICS 2024年第7期47卷 1394-1413页

作者： Beyer, Yannic Steen, Meiko Hecker, Peter Braunschweig Inst Technol Inst Flight Guidance Hermann Blenk Str 27 D-38108 Braunschweig Germany

Active gust load alleviation is an important technology for reducing loads on future commercial airplanes so that the structure can be designed to be lighter in order to save fuel. For the intense reduction of gust loads, a highly reactive control system of sensors, control algorithms, and actuators is required, which is not yet available. In this paper, a control algorithm based on incremental nonlinear dynamic inversion is extended so that actuators respond faster. The control algorithm is applied to a future medium-range aircraft with distributed trailing-edge flaps. It is assumed that the vertical acceleration of the center of gravity and the displacement, velocity, and acceleration of the first wing bending mode are available as feedback variables. To allow comparability with other actuator and sensor setups, the authors abstract the actuator dynamics and sensor filter as control system time delay. The feedback gains are adjusted automatically to the control system time delay. In simulation, the authors investigate the influence of the control system time delay on the peak gust loads. They show that gust loads can indeed be intensely reduced with sufficiently small control system time delay in simulation.

关键词： Incremental Nonlinear Dynamic Inversion Aerodynamic Force Aeroplane Linear Actuator Control System Sensors Sensors Aircraft Wing Components algorithms and data structures Aerodynamic Performance Model Reference Adaptive Control

来源：评论

学校读者我要写书评

暂无评论

OPTIMAL PARALLEL algorithms FOR RECTILINEAR LINK-DISTANCE PROBLEMS

引用

ALGORITHMICA 1995年第3期14卷 261-289页

作者： LINGAS, A MAHESHWARI, A SACK, JR TATA INST FUNDAMENTAL RES COMP SYST & COMMUN GRPBOMBAY 400005MAHARASHTRAINDIA CARLETON UNIV SCH COMP SCIOTTAWAON K1S 5B6CANADA

We provide optimal parallel solutions to several link-distance problems set in trapezoided rectilinear polygons. All our main parallel algorithms are deterministic acid designed to run on the exclusive read exclusive write parallel random access machine (EREW PRAM). Let P be a trapezoided rectilinear simple polygon with n vertices. In O(log n) time using O(n/log n) processors we can optimally compute: 1. Minimum rectilinear link paths, or shortest paths in the L(1) metric from any point in P to all vertices of P. 2. Minimum rectilinear link paths from any segment inside P to all vertices of P. 3. The rectilinear window (histogram) partition of P. 4. Both covering radii and vertex intervals for any diagonal of P. 5. A data structure to support rectilinear link-distance queries between any two points in P (queries can be answered optimally in O(log n) time by uniprocessor). Our solution to 5 is based on a new linear-time sequential algorithm for this problem which is also provided here. This improves on the previously best-known sequential algorithm for this problem which used O(n log n) time and space.(5) We develop techniques for solving link-distance problems in parallel which are expected to find applications in the design of other parallel computational geometry algorithms. We employ these parallel techniques, for example, to compute (on a CREW PRAM) optimally the link diameter, the link center, and the central diagonal of a rectilinear polygon.

关键词： COMPUTATIONAL GEOMETRY algorithms and data structures PARALLEL COMPUTATION LINK DISTANCE RECTILINEAR POLYGONS

来源：评论

学校读者我要写书评

暂无评论

Minimizing the Aggregate Movements for Interval Coverage

引用

ALGORITHMICA 2017年第1期78卷 47-85页

作者： Andrews, Aaron M. Wang, Haitao Utah State Univ Dept Comp Sci Logan UT 84322 USA

We consider an interval coverage problem. Given n intervals of the same length on a line L and a line segment B on L, we want to move the intervals along L such that every point of B is covered by at least one interval and the sum of the moving distances of all intervals is minimized. As a basic geometry problem, it has applications in mobile sensor barrier coverage in wireless sensor networks. The previous work solved the problem in O(n(2)) time. In this paper, by discovering many interesting observations and developing new algorithmic techniques, we present an O(n log n) time algorithm. We also show an Omega (n log n) time lower bound for this problem, which implies the optimality of our algorithm.

关键词： Interval coverage min-sum Barrier coverage Mobile sensors algorithms and data structures Computational geometry

来源：评论

学校读者我要写书评

暂无评论

Fast Elastic Peak Detection for Mass Spectrometry data Mining

引用

IEEE TRANSACTIONS ON KNOWLEDGE AND data ENGINEERING 2012年第4期24卷 634-648页

作者： Zhang, Xin Shasha, Dennis Song, Yang Wang, Jason T. L. NYU Courant Inst Math Sci Dept Comp Sci New York NY 10012 USA New Jersey Inst Technol Dept Comp Sci Newark NJ 07102 USA

We study a data mining problem concerning the elastic peak detection in 2D liquid chromatography-mass spectrometry (LC-MS) data. These data can be modeled as time series, in which the X-axis represents time points and the Y-axis represents intensity values. A peak occurs in a set of 2D LC-MS data when the sum of the intensity values in a sliding time window exceeds a user-determined threshold. The elastic peak detection problem is to locate all peaks across multiple window sizes of interest in the data set. We propose a new data structure, called a Shifted Aggregation Tree or AggTree for short, and use the data structure to find the different peaks. Our method, called PeakID, solves the elastic peak detection problem in 2D LC-MS data yielding neither false positives nor false negatives. The method works by first constructing an AggTree in a bottom-up manner from the given data set, and then searching the AggTree for the peaks in a top-down manner. We describe a state-space algorithm for finding the topology and structure of an efficient AggTree to be used by PeakID. Our experimental results demonstrate the superiority of the proposed method over other methods on both synthetic and real-world data.

关键词： Knowledge discovery from LC-MS data time series data mining bioinformatics computational proteomics algorithms and data structures

来源：评论

学校读者我要写书评

暂无评论

One-dimensional k-center on uncertain data

引用

THEORETICAL COMPUTER SCIENCE 2015年 602卷 114-124页

作者： Wang, Haitao Zhang, Jingru Utah State Univ Dept Comp Sci Logan UT 84322 USA

Problems on uncertain data have attracted significant attention due to the imprecise nature of many measurement data. In this paper, we consider the k-center problem on one-dimensional uncertain data. The input is a set of (weighted) uncertain points on a real line, and each uncertain point is specified by its probability density function (pdf) which is a piecewise-uniform function (i.e., a histogram). The goal is to find a set Q of k points on the line to minimize the maximum expected distance from the uncertain points of P to their expected closest points in Q. We present efficient algorithms for this uncertain k-center problem and their running times almost match those for the "deterministic" k-center problem. (C) 2015 Elsevier B.V. All rights reserved.

关键词： Facility locations k-center Uncertain data algorithms and data structures Computational geometry

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：