检索结果-内蒙古大学图书馆

North American Power Symposium (NAPS)

作者： Nagarajan, Adarsh Ayyanar, Raja Arizona State Univ Dept Elect Engn Tempe AZ 85287 USA

ISBN: (纸本)9781479959044

This paper proposes a network modeling technique using a graph search algorithm for model development of large distribution feeders in an electromagnetic transient program. Large scale penetration of distributed energy resources in the existing distribution feeders impacts the dynamic behavior and pose the motivation to perform a transient analysis on the distribution feeders. This paper proposes a generalized framework to develop the feeder model suitable for transient analysis. A complete model of the distribution feeder will be developed with the purpose to capture the long-term transients such as interaction with other control devices, cloud transients, and voltage flicker. For this purpose a test distribution system is chosen with 738 nodes, 1142 sections, 174 transformers, 107 PV generators, and 287 spot loads. The test feeder has been modeled in MATLAB/Simulink for performing the transient analysis.

关键词： EMTP distributed power generation distribution networks graph theory search problems MATLAB Simulink cloud transients control devices distributed energy resources electromagnetic transient program graph search algorithms large distribution feeders large distribution feeders modeling model development transient analysis voltage flicker Algorithm design and analysis Analytical models Generators Load modeling Mathematical model Software packages Transient analysis Transient analysis Electromagnetic Transients Program Voltage flicker searchING ALGORITHM distributed energy resources distribution feeder Control apparatus Algorithm design and analysis model design distributed power generation tabu search Software packages Load modeling dynamos Power grids

来源：评论

学校读者我要写书评

暂无评论

Using machine learning models to predict and choose meshes reordered by graph algorithms to improve execution times for hydrological modeling

引用

ENVIRONMENTAL MODELLING & SOFTWARE 2019年 119卷 84-98页

作者： Leonard, Lorne Penn State Univ Dept Civil & Environm Engn University Pk PA 16802 USA Penn State Univ Dept Comp Sci & Engn University Pk PA 16802 USA Penn State Univ Dept Plant Sci 245 Agr Sci & Ind Bldg University Pk PA 16802 USA

Is it possible to predict the execution time of a spatially distributed hydrological model by only examining the mesh? This article investigates this question by using a benchmark mesh with the Penn State Integrated Hydrologic Model (PIHM). The benchmark mesh triangles are reordered using ten different graph search algorithms that treat each mesh triangle as a graph root to select the remaining triangles in the watershed domain. PIHM then executed these graph-reordered meshes to create performance datasets to find which graph search algorithm and triangle root combinations improved PIHM's execution time. The performance datasets were used to train and classify seven different machine learning (ML) models to predict the fastest execution times. Analyzing these ML results facilitated a strategy for end users of the HydroTerre expert system to choose meshes that improve execution times for their hydrological science research with PIHM.

关键词： Meshes HydroTerre PIHM Machine learning models graph search algorithms Distributed hydrological model

来源：评论

学校读者我要写书评

暂无评论

Minimizing the average searching time for an object within a graph

引用

COMPUTATIONAL OPTIMIZATION AND APPLICATIONS 2019年第2期74卷 517-545页

作者： Teller, Ron Zofi, Moshe Kaspi, Moshe Ben Gurion Univ Negev Dept Ind Engn & Management Beer Sheva Israel Sapir Coll Dept Ind Management Sderot Israel

This paper presents a new graph search problem for which a searcher wishes to find an object that may be found at a set of locations. The searcher doesn't know the object's exact location, but does know the a-prior probability of finding the object at each location. He wishes to build a searching path for reaching the object that starts from a given location and ends when reaching the object (or after searching the entire set with a false result). The objective is to find a searching path which will minimize the average searching time. We consider two scenarios for this problem: one when there is an unknown number of objects on the set and another when there is exactly one object on the set (the sum of probabilities is equal to 1). We show that this problem is NP-Hard, and supply a branch and bound algorithm for finding an optimal solution for large scale problems. We also study greedy approaches and other heuristics and compare the performance of these algorithms in various situations.

关键词： graph search algorithms Object searching Branch and bound Dynamic programming Greedy algorithm Heuristic search TSP Ant colony optimization

来源：评论

学校读者我要写书评

暂无评论

Methods for Dynamic Analysis of Distribution Feeders with High Penetration of PV Generators 43

Methods for Dynamic Analysis of Distribution Feeders with Hi...

引用

43rd IEEE Photovoltaic Specialists Conference (PVSC)

作者： Nagarajan, Adarsh Ayyanar, Raja Natl Renewable Energy Lab Golden CO 80401 USA Arizona State Univ Tempe AZ 85287 USA

ISBN: (纸本)9781509027248

An increase in the number of inverter-interfaced photovoltaic (PV) generators on existing distribution feeders affects the design, operation, and control of the distribution systems. Existing distribution system analysis tools are capable of supporting only snapshot and quasi-static analyses. Capturing the dynamic effects of PV generators during the variation in distribution system states is necessary when studying the effects of controller bandwidths, multiple voltage correction devices, and anti-islanding. This work explores the use of dynamic phasors and differential algebraic equations (DAE) for impact analysis of PV generators on the existing distribution feeders.

关键词： dynamic analysis dynamic phasor quasi-static analysis network reduction graph search algorithms

来源：评论

学校读者我要写书评

暂无评论

Oriented relative fuzzy connectedness: theory, algorithms, and its applications in hybrid image segmentation methods

引用

EURASIP JOURNAL ON IMAGE AND VIDEO PROCESSING 2015年第1期2015卷 1页

作者： Ccacyahuillca Bejar, Hans Harley Miranda, Paulo Av Univ Sao Paulo Dept Comp Sci BR-05508090 Sao Paulo Brazil

Anatomical structures and tissues are often hard to be segmented in medical images due to their poorly defined boundaries, i.e., low contrast in relation to other nearby false boundaries. The specification of the boundary polarity can help alleviate a part of this problem. In this work, we discuss how to incorporate this property in the relative fuzzy connectedness (RFC) framework. We include a theoretical proof of the optimality of the new algorithm, named oriented relative fuzzy connectedness (ORFC), in terms of an oriented energy function subject to the seed constraints, and show its usage to devise powerful hybrid image segmentation methods. The methods are evaluated using medical images of MRI and CT of the human brain and thoracic studies.

关键词： Relative fuzzy connectedness Image foresting transform graph cut segmentation graph search algorithms

来源：评论

学校读者我要写书评

暂无评论

Oriented Image Foresting Transform Segmentation by Seed Competition

引用

IEEE TRANSACTIONS ON IMAGE PROCESSING 2014年第1期23卷 389-398页

作者： Miranda, Paulo A. V. Mansilla, Lucy A. C. Univ Sao Paulo Inst Math & Stat Dept Comp Sci BR-05508090 Sao Paulo Brazil

Seed-based methods for region-based image segmentation are known to provide satisfactory results for several applications, being usually easy to extend to multidimensional images. However, while boundary-based methods like live wire can easily incorporate a preferred boundary orientation, region-based methods are usually conceived for undirected graphs, and do not resolve well between boundaries with opposite orientations. This motivated researchers to investigate extensions for some region-based frameworks, seeking to better solve oriented transitions. In this same spirit, we discuss how to incorporate this orientation information in a region-based approach called "IFT segmentation by seed competition" by exploring digraphs. We give direct proof for the optimality of the proposed extensions in terms of energy functions associated with the cuts. To stress these theoretical results, we also present an experimental evaluation that shows the obtained gains in accuracy for some 2D and 3D data sets of medical images.

关键词： graph search algorithms image foresting transform shortest paths graph-cut segmentation watersheds fuzzy connectedness

来源：评论

学校读者我要写书评

暂无评论

graph representation of n-dimensional space

引用

Advances in Manufacturing 2014年第1期2卷 54-60页

作者： Tomasz Kosicki Department of Production and Quality Engineering Norwegian University of Science and Technology

This paper investigates how graph representation can be created for the mesh which is a discrete approximation of n-dimensional continuous space. The paper discusses the relationship between mesh dimensionality and the type and quantity of edges connecting each vertex with its neighbors. Basing on the analysis, a simple algorithm is also proposed to create such graph representation. The purpose of the graph is to search optimal paths and trajectories in the represented space.

关键词： Trajectory optimization Path optimization graph search algorithms

来源：评论

学校读者我要写书评

暂无评论

Oriented Relative Fuzzy Connectedness: Theory, algorithms, and Applications in Image Segmentation 27

Oriented Relative Fuzzy Connectedness: Theory, Algorithms, a...

引用

27th SIBGRAPI Conference on graphics, Patterns and Images (SIBGRAPI)

作者： Ccacyahuillca Bejar, Hans Harley Miranda, Paulo A. V. Univ Sao Paulo Dept Comp Sci BR-05508090 Sao Paulo SP Brazil

ISBN: (纸本)9781479942602

Anatomical structures and tissues are often hard to be segmented in medical images due to their poorly defined boundaries, i.e., low contrast in relation to other nearby false boundaries. The specification of the boundary polarity can help to alleviate part of this problem. In this work, we discuss how to incorporate this property in the Relative Fuzzy Connectedness (RFC) framework. We include a theoretical proof of the optimality of the new algorithm, named Oriented Relative Fuzzy Connectedness (ORFC), in terms of an oriented energy function subject to the seed constraints, and show the obtained gains in accuracy using medical images of MRI and CT images of thoracic studies.

关键词： Relative Fuzzy Connectedness image foresting transform graph-cut segmentation graph search algorithms

来源：评论

学校读者我要写书评

暂无评论

Minimal functional routes in directed graphs with dependent edges

引用

INTERNATIONAL TRANSACTIONS IN OPERATIONAL REsearch 2013年第3期20卷 391-409页

作者： Wang, Rui-Sheng Sun, Zhongyao Albert, Reka Penn State Univ Dept Phys University Pk PA 16802 USA

graphs are mathematical structures used to model a set of objects and the relations between them. One of the basic concepts of graph theory, the path, has wide real-world applications. In classic graph models, edges ending at a node are assumed to be independent. However, many real graphs/networks can only be correctly described by considering a dependency among nodes or edges. Paths in such graphs may not be functional if the conditional dependency is ignored. In this study, we investigate the routing problem in directed graphs with dependent edges represented by general graph models as alternatives to hypergraphs. We define a minimal functional route (MFR) as a minimal set of nodes and edges that can independently perform information transfer between two given nodes, and formulate the determination of MFRs as a graph search problem. A depth-first-search (DFS) top-down algorithm, an iterative integer linear programming (ILP) bottom-up algorithm, and a subgraph-growing bottom-up algorithm are devised subsequently to solve this problem. Numerical experiments verify the effectiveness of the algorithms. The defined MFR problem and the proposed algorithms are expected to find many practical applications.

关键词： graph search algorithms minimal functional routes directed graphs dependent edges

来源：评论

学校读者我要写书评

暂无评论

Image Segmentation by Oriented Image Foresting Transform with Geodesic Star Convexity

引用

15th International Conference on Computer Analysis of Images and Patterns (CAIP)

作者： Mansilla, Lucy A. C. Miranda, Paulo A. V. Univ Sao Paulo Dept Comp Sci BR-05508090 Sao Paulo Brazil

ISBN: (纸本)9783642402616

Anatomical structures and tissues are often hard to be segmented in medical images due to their poorly defined boundaries, i.e., low contrast in relation to other nearby false boundaries. The specification of the boundary polarity and the usage of shape constraints can help to alleviate part of this problem. Recently, an Oriented Image Foresting Transform (OIFT) has been proposed. In this work, we discuss how to incorporate Gulshan's geodesic star convexity prior in the OIFT approach for interactive image segmentation, in order to simultaneously handle boundary polarity and shape constraints. This convexity constraint eliminates undesirable intricate shapes, improving the segmentation of objects with more regular shape. We include a theoretical proof of the optimality of the new algorithm in terms of a global maximum of an oriented energy function subject to the shape constraints, and show the obtained gains in accuracy using medical images of thoracic CT studies.

关键词： graph search algorithms image foresting transform graph-cut segmentation geodesic star convexity

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：