检索结果-内蒙古大学图书馆

9th ACM International Conference on Bioinformatics, Computational Biology, and Health Informatics (ACM-BCB)

作者： Pratapa, Aditya Jalihal, Amogh P. Ravi, S. S. Murali, T. M. Virginia Tech Dept Comp Sci Blacksburg VA 24061 USA Virginia Tech Genet Bioinformat & Computat Biol Blacksburg VA USA Virginia Tech Biocomplex Inst Blacksburg VA USA SUNY Albany Dept Comp Sci Albany NY 12222 USA

ISBN: (纸本)9781450357944

The genetic cross is a fundamental, flexible, and widely-used experimental technique to create new mutant strains from existing ones. Surprisingly, the problem of how to efficiently compute a sequence of crosses that can make a desired target mutant from a set of source mutants has received scarce attention. In this paper, we make three contributions to this question. First, we formulate several natural problems related to efficient synthesis of a target mutant from source mutants. Our formulations capture experimentally-useful notions of verifiability (e.g., the need to confirm that a mutant contains mutations in the desired genes) and permissibility (e.g., the requirement that no intermediate mutants in the synthesis be inviable). Second, we develop combinatorial techniques to solve these problems. We prove that checking the existence of a verifiable, permissible synthesis is NP-complete in general. We complement this result with three polynomial time or fixed-parameter tractable algorithms for optimal synthesis of a target mutant for special cases of the problem that arise in practice. Third, we apply these algorithms to simulated data and to synthetic data. We use results from simulations of a mathematical model of the cell cycle to replicate realistic experimental scenarios where a biologist may be interested in creating several mutants in order to verify model predictions. Our results show that the consideration of permissible mutants can affect the existence of a synthesis or the number of crosses in an optimal one. Our algorithms gracefully handle the restrictions that permissible mutants impose. Results on synthetic data show that our algorithms scale well with increases in the size of the input and the fixed parameters.

关键词： experiment planning genetic crosses multi-gene mutants fixed-parameter tractability combinatorial algorithms mathematical models

来源：评论

学校读者我要写书评

暂无评论

A Minimum Cover Algorithm for PMU Placement in Power System Networks Under Line Observability Constraints

A Minimum Cover Algorithm for PMU Placement in Power System ...

引用

General Meeting of the IEEE-Power-and-Energy-Society

作者： Anderson, Joel E. Chakrabortty, Aranya N Carolina State Univ Dept Elect & Comp Engn Raleigh NC 27695 USA

ISBN: (纸本)9781467327299

In this paper we develop a graph-theoretic PMU placement algorithm for multi-area power system networks with the objective of identifying a dynamic equivalent model for the system. The system is considered to be divided into clusters or areas of synchronous generators, with each area connected to other sets of areas through designated transmission networks. The buses in the system are accordingly divided into two types, namely - boundary buses of the areas and boundary buses of the transmission networks. We first show that in order to derive the equivalent line parameters connecting the different areas we must have PMUs placed at the minimum vertex cover of the bipartite graphs formed between every pair of node-sets arising out of the boundary buses of the areas and those of the corresponding transmission networks they are connected to. Considering further that the number of tie-lines observable from any given PMU is constrained by an upper limit, we derive an algorithm to compute the sub-optimal minimum cover for the multi-area system. The method is illustrated via a 4-6 bipartite network, as well as with two small examples from the WECC system. Statistical analyses of the algorithm are also presented describing how the final set of chosen PMU locations as well as the computational time needed to run the algorithm are dependent on the size, complexity and measurement constraints of the network.

关键词： Phasor measurement unit (PMU) placement equivalent models graph theory minimum cover combinatorial algorithms Konig's theorem

来源：评论

学校读者我要写书评

暂无评论

On Coxeter spectral study of finite posets using computer algebra tools

引用

Electronic Notes in Discrete Mathematics 2013年 40卷 121-127页

作者： Gasiorek, Marcin Simson, Daniel Zajac, Katarzyna Faculty of Mathematics and Computer Science Nicolaus Copernicus University Toruń Poland

We study a class of posets with a non-negativity condition by means of Coxeter spectral properties of the simply-laced Euclidean diagrams {D~n,n≥4,E~6,E~7,E~8}. We show that symbolic and numerical computer calculatio... 详细信息

We study a class of posets with a non-negativity condition by means of Coxeter spectral properties of the simply-laced Euclidean diagrams {D~_n,n≥4,E~₆,E~₇,E~₈}. We show that symbolic and numerical computer calculations in Python, C and Linux tools allow us to compute a complete list of these posets J, with at most 15 points, by means of their Coxeter spectra speccJ⊆C. © 2013 Elsevier B.V.

关键词： combinatorial algorithms Coxeter polynomial Euclidean diagram Poset Principal quadratic form Python

来源：评论

学校读者我要写书评

暂无评论

Determinant Maximization via Matroid Intersection algorithms 63

Determinant Maximization via Matroid Intersection Algorithms

引用

63rd Annual IEEE Symposium on Foundations of Computer Science (FOCS)

作者： Brown, Adam Laddha, Aditi Pittu, Madhusudhan Singh, Mohit Tetali, Prasad Georgia Inst Technol Sch Math Atlanta GA 30332 USA Georgia Inst Technol Coll Comp Atlanta GA 30332 USA Carnegie Mellon Univ Sch Comp Sci Pittsburgh PA 15213 USA Georgia Inst Technol H Milton Stewart Sch Ind & Syst Engn Atlanta GA 30332 USA Carnegie Mellon Univ Math Sci Pittsburgh PA 15213 USA

ISBN: (纸本)9781665455190

Determinant maximization problem gives a general framework that models problems arising in as diverse fields as statistics [1], convex geometry [2], fair allocations [3], combinatorics [4], spectral graph theory [5], network design, and random processes [6]. In an instance of a determinant maximization problem, we are given a collection of vectors U = {nu(1),..., nu(n)} subset of R-d, and a goal is to pick a subset S subset of U of given vectors to maximize the determinant of the matrix Sigma(i is an element of S) nu(i)nu(inverted perpendicular)(i). Often, the set S of picked vectors must satisfy additional combinatorial constraints such as cardinality constraint (|S| <= k) or matroid constraint ( S is a basis of a matroid defined on the vectors). In this paper, we give a polynomial-time deterministic algorithm that returns a r(O(r))-approximation for any matroid of rank r <= d. This improves previous results that give e(O(r2))-approximation algorithms relying on e(O(r))-approximate estimation algorithms [4], [7]-[9] for any r <= d. All previous results use convex relaxations and their relationship to stable polynomials and strongly log-concave polynomials or non-convex relaxations for the problem [10]. In contrast, our algorithm builds on combinatorial algorithms for matroid intersection, which iteratively improve any solution by finding an alternating negative cycle in the exchange graph defined by the matroids. While the det(.) function is not linear, we show that taking appropriate linear approximations at each iteration suffice to give the improved approximation algorithm.

关键词： Computations on discrete structures Linear approximation combinatorial algorithms

来源：评论

学校读者我要写书评

暂无评论

Estimating all possible SUR models with permuted exogenous data matrices derived from a VAR process

引用

JOURNAL OF ECONOMIC DYNAMICS & CONTROL 2006年第5期30卷 721-739页

作者： Gatu, C Kontoghlorghes, EJ Univ Neuchatel Inst Informat CH-2007 Neuchatel Switzerland Univ Cyprus Dept Publ & Business Adm CY-1678 Nicosia Cyprus Univ London Birkbeck Coll Sch Comp Sci & Informat Syst London WC1E 7HX England

The Vector Autoregressive (VAR) process with zero coefficient constraints can be formulated as a Seemingly Unrelated Regressions (SUR) model. Within the context of subset VAR model selection a computationally efficient strategy to generate and estimate all G! SUR models when permuting the exogenous data matrices is proposed, where G is the number of the regression equations. The combinatorial algorithm is based on orthogonal transformations, exploits the particular structure of the modified models and avoids the estimation of these models afresh by utilizing previous computation. Theoretical measurements of complexity are derived to prove the efficiency of the proposed algorithm. (c) 2005 Elsevier B.V. All rights reserved.

关键词： subset vector autoregressive model selection seemingly unrelated regressions models least squares QR decomposition combinatorial algorithms

来源：评论

学校读者我要写书评

暂无评论

Influence of Professor T. C. Hu's Works on Fundamental Approaches in Layout 18

Influence of Professor T. C. Hu's Works on Fundamental Appro...

引用

ACM International Symposium on Physical Design (ISPD)

作者： Kahng, Andrew B. UCSD Dept CSE La Jolla CA 92093 USA UCSD Dept ECE La Jolla CA 92093 USA

ISBN: (纸本)9781450356268

Professor T. C. Hu has made numerous pioneering and fundamental contributions in combinatorial algorithms, mathematical programming and operations research. His seminal 1985 IEEE book VLSI Circuit Layout: Theory and Design, coedited with Prof. E. S. Kuh, shaped algorithmic and optimization perspectives, as well as basic frameworks, for IC physical design throughout the following decades [44]. Indeed, Professor Hu gave a keynote address at the very first International Symposium on Physical Design, in April 1997 [41]. His research approach of (i) studying small and/or extremal cases first, (ii) always seeking to establish error bounds or other properties of heuristic outcomes (hence, always seeking to understand optimal solutions), (iii) approaching new problems from as fresh a perspective as possible, and (iv) pursuing simplicity and beauty in both formulation and exposition, has influenced generations of researchers. This paper complements [20] in recounting highlights of Professor Hu's contributions to, and impacts on, physical design. The focus is on several problems of "connection", as well as the concept of "shadow price", as they relate to layout.

关键词： tribute combinatorial algorithms mathematical programming operations research physical design

来源：评论

学校读者我要写书评

暂无评论

Engineering a Distributed Histogram Sort

Engineering a Distributed Histogram Sort

引用

IEEE International Conference on Cluster Computing (IEEE CLUSTER)

作者： Kowalewski, Roger Jungblut, Pascal Fuerlinger, Karl Ludwig Maximilians Univ Munchen Inst Informat Munich Germany

ISBN: (纸本)9781728147345

Sorting is one of the most critical non-numerical algorithms and covers use cases in a wide spectrum of scientific applications. Although we can build upon excellent research over the last decades, scaling to thousands of processing units on modern many-core architectures reveals a gap between theory and practice. We adopt ideas of the well-known quickselect and sample sort algorithms to minimize data movement. Our evaluation demonstrates that we can keep up with recently proposed distribution sort algorithms in large-scale experiments, without any assumptions on the input keys. Additionally, our implementation outperforms an efficient multi-threaded merge sort on a single node. Our implementation is based on a C++ PGAS approach with an STL-like interface and can easily be integrated into many application codes. As part of the presented experiments, we further reveal challenges with multi-threaded MPI and one-sided communication.

关键词： Sorting Searching combinatorial algorithms PGAS

来源：评论

学校读者我要写书评

暂无评论

Extreme elevation on a 2-manifold

Extreme elevation on a 2-manifold

引用

20th ACM Symposium on Computational Geometry

作者： Agarwal, Pankaj K. Edelsbrunner, Herbert Harer, John Wang, Yusu Duke Univ Dept Comp Sci Durham NC 27708 USA Raindrop Geometr Res Triangle Pk NC 27709 USA Duke Univ Dept Math Durham NC 27708 USA

Given a smoothly embedded 2-manifold in R-3, we define the elevation of a point as the height difference to a canonically defined second point on the same manifold. Our definition is invariant under rigid motions and can be used to define features such as lines of discontinuous or continuous but non-smooth elevation. We give an algorithm for finding points of locally maximum elevation, which we suggest mark cavities and protrusions and are useful in matching shapes as for example in protein docking.

关键词： combinatorial algorithms Critical points Morse functions Pedal function Persistence Surgery Triangulations

来源：评论

学校读者我要写书评

暂无评论

Approximate Function Matching under δ- and γ- Distances

Approximate Function Matching under δ- and γ- Distances

引用

19th International Symposium on String Processing and Information Retrieval (SPIRE) / 8th Latin American Web Congress (LA-WEB)

作者： Mendivelso, Juan Lee, Inbok Pinzon, Yoan J. Univ Nacl Colombia Res Grp Algorithms & Combinator ALGOS UN Dept Comp Sci & Ind Engn Bogota Colombia

ISBN: (纸本)9783642341083;9783642341090

This paper defines a new string matching problem by combining two paradigms: function matching and delta gamma-matching. The result is an approximate variant of function matching where two equal-length strings X and Y match if there exists a function that maps X to a string X' such that X' and Y are delta gamma-similar. We propose an O(nm) algorithm for finding all the matches of a pattern P-1...m in a text T-1...n.

关键词： combinatorial algorithms delta-matching gamma-matching delta gamma-matching function matching

来源：评论

学校读者我要写书评

暂无评论

EFFICIENT AUTOMATIC PART NESTING ON IRREGULAR AND INHOMOGENEOUS SURFACES

EFFICIENT AUTOMATIC PART NESTING ON IRREGULAR AND INHOMOGENE...

引用

4TH ANNUAL ACM-SIAM SYMP ON DISCRETE algorithms

作者： HEISTERMANN, J LENGAUER, T German Natl Research Cent for Computer Science (GMD) Germany

ISBN: (纸本)0898713137

The part-nesting problem is the problem of arranging a set of two-dimensional irregular shapes, the parts on a plane irregularly shaped surface, such that no shapes overlap and as much of the surface is covered as possible. This problem occurs in several applications in the textile business. One of the most challenging applications appear in the leather industry. This application is characterized by a high degree of inhomogeneity of the surface as well as the shapes and by severe restrictions on run time. We present an algorithmic method for computer-aided nesting in this context. The algorithm is characterized by selective data reduction, sequential part placement, a topological part fitting process, and a carefully tuned evaluation function for partial placements. Experiments show that the method is competitive with nestings done by man, for relatively nicely behaved part sets and surfaces. Our nesting algorithm has been in industrial use since June 1992.

关键词： combinatorial algorithms GREEDY METHOD 2-DIMENSIONAL PLACEMENT NESTING PROBLEM CUTTING-STOCK PROBLEM TRIM-LOSS PROBLEM

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：