检索结果-内蒙古大学图书馆

Solving GNOVI frameworks involving (γ_G, λ)-weak-GRD set-valued mappings in positive Hilbert spaces

FIXED POINT THEORY AND APPLICATIONS 2014年第1期2014卷 146-146页

作者： Li, Hong Gang Pan, Xian Bing Deng, Zhi Ying Wang, Chang You Chongqing Univ Posts & Telecommun Coll Math & Phys Nonlinear Anal Inst Inst Appl Math Res Chongqing 400065 Peoples R China Chongqing Univ Posts & Telecommun Coll Mobile Telecommun Hecuan 400065 Peoples R China

First, a new concept, positive Hilbert spaces, is introduced and some fundamental inequalities which are applied to studying the properties of the resolvent operator associated for (gamma(G), lambda)-weak-GRD set-valued mappings are introduced and discussed in positive Hilbert spaces. Next, by using the resolvent operator and fixed point theory, an existence theorem and an approximation algorithm to solve a new class of general nonlinear ordered inclusions are established and suggested. In this field, the results obtained seem to be general in nature.

关键词： general nonlinear ordered inclusion frameworks positive Hilbert spaces inequalities (gamma(G), lambda)-weak-GRD set-valued mapping approximation algorithm

来源：评论

学校读者我要写书评

暂无评论

Multi-Satellite Imaging Task Planning for Large Regional Coverage: A Heuristic algorithm Based on Triple Grids Method

引用

REMOTE SENSING 2024年第1期16卷 194页

作者： Li, Feng Wan, Qiuhua Wen, Feifei Zou, Yongkui He, Qien Li, Da Zhong, Xing Garzelli, Andrea Chinese Acad Sci Changchun Inst Opt Fine Mech & Phys Changchun 130033 Peoples R China Univ Chinese Acad Sci Daheng Coll Beijing 100049 Peoples R China Chang Guang Satellite Technol Co Ltd Changchun 130102 Peoples R China Jilin Univ Sch Math Changchun 130012 Peoples R China

Over the past few decades, there has been a significant increase in the number of Earth observation satellites, and the area of ground targets requiring observation has also been expanding. To effectively utilize the capabilities of these satellites and capture larger areas of ground targets, it has become essential to plan imaging tasks for large regional coverage using multiple satellites. First, we establish a 0-1 integer programming model to accurately describe the problem and analyze the challenges associated with solving the model. Second, we propose a heuristic algorithm based on the triple grids method. This approach utilizes a generated grid to create fewer candidate strips, a calculation grid to determine the effective coverage area more accurately, and a refined grid to solve the issue of repeated coverage of strips. Furthermore, we employ an approximation algorithm to further improve the solutions obtained from the heuristic algorithm. By comparing the proposed method to the traditional greedy heuristic algorithm and three evolutionary algorithms, the results show that our method has better performance in terms of coverage and efficiency.

关键词： multi-satellite large regional coverage heuristic algorithm triple grids method approximation algorithm

来源：评论

学校读者我要写书评

暂无评论

Optimal gateway placement for hybrid BANETs-sensor networks in urban areas

引用

INTERNATIONAL JOURNAL OF SENSOR NETWORKS 2018年第4期26卷 243-251页

作者： Liu, Chunyan Huang, Hejiao Du, Hongwei Jia, Xiaohua Harbin Inst Technol Dept Comp Sci & Technol Shenzhen Key Lab Internet Informat Collaborat Shenzhen 518055 Guangdong Peoples R China

For a given urban area, we apply the existing bus-based ad hoc networks (BANETs) to collect and transmit information, monitored by wireless sensor networks (WSNs), from subareas to the data center. Sensors are well deployed in each subareas divided by streets. WSNs and BANETs are heterogeneous and minimal gateways are required to connect the both kinds of networks. In this paper, we provide two gateway placement problems" minimum gateways placement and minimal gateways placement with minimum average delay. We present two constant algorithm MGPPA and MADGPPA to solve the two problems, respectively. Theoretical analysis demonstrates that MGPPA is a (1 + In lambda)-approximation algorithm and MADGPPA is a lambda-approximation algorithm correspondingly, where lambda is the maximum number of subareas covered by a gateway candidate. In the geometric topology of the grid urban area, lambda <= 4. Extensive comparison simulation show the performance of minimum gateways and minimal gateways with minimum average delay achieves significantly.

关键词： WSNs wireless sensor networks bus-based adhoc networks gateway placement approximation algorithm

来源：评论

学校读者我要写书评

暂无评论

STATION LAYOUTS IN THE PRESENCE OF LOCATION CONSTRAINTS

引用

Journal of Interconnection Networks 2002年第1N02期3卷 1-17页

作者： PROSENJIT BOSE EVANGELOS KRANAKIS CHRISTOS KAKLAMANIS LEFTERIS M. KIROUSIS DANNY KRIZANC DAVID PELEG Carleton University School of Computer Science Ottawa Ontario K1S 5B6 Canada University of Patras Department of Computer Engineering and Informatics GR-26504 Patras Greece Wesleyan University Department of Mathematics Middletown CT 06459 USA Weizmann Institute of Science Department of Computer Science and Applied Mathematics Rehovot 76100 Israel

In wireless communication, the signal of a typical broadcast station is transmitted from a broadcast center p and reaches objects at a distance, say, r from it. In addition there is a radius r 0 , r 0 < r, such that the signal originating from the center of the station is so strong that human habitation within distance r 0 from the center p should be avoided. In other words, points within distance r 0 from the station comprise a hazardous zone. We consider the following station layout proble: Cover a given planar region that includes a collection of buildings with a minimum number of stations so that every point in the region is within the reach of a station, while at the same time no interior point of any building is within the hazardous zone of a station. We give algorithms for computing such station layouts in both the one- and two-dimensional cases.

关键词： approximation algorithm Broadcast station Health hazards Optimal layout Wireless communication

来源：评论

学校读者我要写书评

暂无评论

An: 收藏
分享
引用; SIAM Journal on Computing 2012年第5期41卷 1095-1109页; 作者： Jittat Fakcharoenphol Bundit Laekhanukit; We present an O(log2<span class="mi" id="MathJax-Span-26" style="font-family: MathJax_Ma; We present an $O (\log^{2} k)$; 来源：评论; 学校读者我要写书评

暂无评论

View-based Explanations for Graph Neural Networks

引用

Proceedings of the ACM on Management of Data 2024年第1期2卷 1-27页

作者： Tingyang Chen Dazhuo Qiu Yinghui Wu Arijit Khan Xiangyu Ke Yunjun Gao Zhejiang University Ningbo China Aalborg University Aalborg Denmark Case Western Reserve University Cleveland USA Zhejiang University & Zhejiang University Ningbo China Zhejiang University Hangzhou China

Generating explanations for graph neural networks (GNNs) has been studied to understand their behaviors in analytical tasks such as graph classification. Existing approaches aim to understand the overall results of GNNs rather than providing explanations for specific class labels of interest, and may return explanation structures that are hard to access, nor directly queryable. We propose GVEX, a novel paradigm that generates Graph Views for GNN EXplanation. (1) We design a two-tier explanation structure called explanation views. An explanation view consists of a set of graph patterns and a set of induced explanation subgraphs. Given a database G of multiple graphs and a specific class label l assigned by a GNN-based classifier M, it concisely describes the fraction of G that best explains why l is assigned by M. (2) We propose quality measures and formulate an optimization problem to compute optimal explanation views for GNN explanation. We show that the problem is Σ2P-hard. (3) We present two algorithms. The first one follows an explain-and-summarize strategy that first generates high-quality explanation subgraphs which best explain GNNs in terms of feature influence maximization, and then performs a summarization step to generate patterns. We show that this strategy provides an approximation ratio of 1/2. Our second algorithm performs a single-pass to an input node stream in batches to incrementally maintain explanation views, having an anytime quality guarantee of 1/4-approximation. Using real-world benchmark data, we experimentally demonstrate the effectiveness, efficiency, and scalability of GVEX. Through case studies, we showcase the practical applications of GVEX.

关键词： approximation algorithm data mining deep learning explainable ai graph neural networks graph views

来源：评论

学校读者我要写书评

暂无评论

Partitioning Into Prescribed Number of Cycles and Mod k T -join With Slack

引用

Procedia Computer Science 2021年 195卷 12-20页

作者： Jordan Barrett Salomon Bendayan Yanjia Li Bruce Reed Department of Mathematics McGill University Montreal Canada Department of Combinatorics & Optimization University of Waterloo Waterloo Canada Department of Computer Science McGill University Montreal Canada

The input to a PPNC instance is integers n and p , and a non-negative real weighting of the edges of the clique K n on the vertex set {1,..., n } . We are asked to find a set of p disjoint cycles spanning {1,..., n } and subject to this such that the sum of the weights of the edges is minimized. We provide an efficient approximation algorithm for the metric version of this problem which has an approximation ratio of 4 if p ≤ n/5 and an approximation ratio of 51 for larger p . For p > n/5, our algorithm uses a subroutine which approximately solves the Mod 3 T -join With Slack problem. The input to an instance of Mod k T -join with Slack consists of integers n and B , a non-negative weighting of the edges of the clique K n , and a label l(v) from {0,1,..., k - 1} on each vertex of K n . We are asked to find the minimum weight spanning forest F from amongst those satisfying ∑ T∈F ((∑ v∈V(T) l(v)) mod k ) ≤ B . If k = 2 and B = 0 this is the well-studied T -join problem which can be solved exactly in polynomial time.

关键词： Hamiltonian p-median problem T -join approximation algorithm Graph partition

来源：评论

学校读者我要写书评

暂无评论

Constructing battery-aware virtual backbones in wireless sensor networks

引用

EURASIP JOURNAL ON WIRELESS COMMUNICATIONS AND NETWORKING 2007年第1期000卷 040154-040154页

作者： Ma, Chi Yang, Yuanyuan Zhang, Zhenghao SUNY Stony Brook Dept Comp Sci Stony Brook NY 11794 USA SUNY Stony Brook Dept Elect & Comp Engn Stony Brook NY 11794 USA Carnegie Mellon Univ Dept Comp Sci Pittsburgh PA 15213 USA

A critical issue in battery-powered sensor networks is to construct energy efficient virtual backbones for network routing. Recent study in battery technology reveals that batteries tend to discharge more power than needed and reimburse the over-discharged power if they are recovered. In this paper we first provide a mathematical battery model suitable for implementation in sensor networks. We then introduce the concept of battery-aware connected dominating set (BACDS) and show that in general the minimum BACDS (MBACDS) can achieve longer lifetime than the previous backbone structures. Then we show that finding a MBACDS is NP-hard and give a distributed approximation algorithm to construct the BACDS. The resulting BACDS constructed by our algorithm is at most (8+Delta) opt size, where. is the maximum node degree and opt is the size of an optimal BACDS. Simulation results show that the BACDS can save a significant amount of energy and achieve up to 30% longer network lifetime than previous schemes.

关键词： Information System Sensor Network Wireless Sensor Network approximation algorithm System Application

来源：评论

学校读者我要写书评

暂无评论

A Primal-Dual-Based Power Control Approach for Capacitated Edge Servers

引用

SENSORS 2022年第19期22卷 7582-7582页

作者： Zhang, Qinghui Li, Weidong Su, Qian Zhang, Xuejie Yunnan Univ Sch Informat Sci & Engn Kunming 650091 Yunnan Peoples R China Yunnan Univ Sch Math & Stat Kunming 650091 Yunnan Peoples R China

The intensity of radio waves decays rapidly with increasing propagation distance, and an edge server's antenna needs more power to form a larger signal coverage area. Therefore, the power of the edge server should be controlled to reduce energy consumption. In addition, edge servers with capacitated resources provide services for only a limited number of users to ensure the quality of service (QoS). We set the signal transmission power for the antenna of each edge server and formed a signal disk, ensuring that all users were covered by the edge server signal and minimizing the total power of the system. This scenario is a typical geometric set covering problem, and even simple cases without capacity limits are NP-hard problems. In this paper, we propose a primal-dual-based algorithm and obtain an m-approximation result. We compare our algorithm with two other algorithms through simulation experiments. The results show that our algorithm obtains a result close to the optimal value in polynomial time.

关键词： power control primal-dual approximation algorithm edge computing power cover

来源：评论

学校读者我要写书评

暂无评论

A Heuristic Approach to Fast NOVCA （Near Optimal Vertex Cover algorithm）

引用

Computer Technology and Application 2014年第2期5卷 83-90页

作者： Sanj aya Gajurel Roger Bielefeld ITS Advanced Research Computing CWR U Cleveland 44106 USA

This paper describes an extremely fast polynomial time algorithm, the NOVCA （Near Optimal Vertex Cover algorithm） that produces an optimal or near optimal vertex cover for any known undirected graph G （V, E）. NOVCA is based on the idea of（l） including the vertex having maximum degree in the vertex cover and （2） rendering the degree of a vertex to zero by including all its adjacent vertices. The three versions of algorithm, NOVCA-I, NOVCA-II, and NOVCA-random, have been developed. The results identifying bounds on the size of the minimum vertex cover as well as polynomial complexity of algorithm are given with experimental verification. Future research efforts will be directed at tuning the algorithm and providing proof for better approximation ratio with NOVCA compared to any available vertex cover algorithms.

关键词： Vertex cover problem combinatorial problem NP-complete problem approximation algorithm optimization algorithms.

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

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