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Deepening the ida* algorithm for knowledge graph reasoning through neural network architecture

NEUROCOMPUTING 2021年 429卷 101-109页

作者： Wang, Qi Hao, Yongsheng Chen, Feng Fudan Univ Shanghai Peoples R China Nanjing Univ Informat Sci & Technol Network Ctr Nanjing Peoples R China Chongqing Univ Posts & Telecommun Sch Software Engn Chongqing Peoples R China

Inferring missing links in Knowledge Graphs (KGs) is a key evaluation task for KG reasoning, which aims to find relations for a given entity pair. Existing research often employs the ida* (Iterative Deepening A*) algorithm for the path discovery task owing to its efficiency and accuracy. However, it relies on heuristics to set cost functions and is also difficult to utilize useful context information in the search process. In this paper, we propose the Deep-ida* framework which applies neural networks and reinforcement learning (RL) to empower the ida* algorithm to tackle the path discovery problem in KG reasoning. We model KG reasoning as a Markov Decision Process (MDP) and divide our Deep-ida* framework and the resulting path into two parts: path-finding and path-reasoning. For path-finding, we propose a policy network to model the cost from the source to a candidate location. In this process, we employ the GCN (Graph Convolutional Network) to embed the observable sub-track, then employ the LSTM (Long Short-Term Memory) to record the historical trajectory, and introduce the attention to utilize the context information, and finally form policy. For path-reasoning with the searched candidate paths passed from the former process, we employ a value network to estimate the cost from the candidate to the destination entity, using the GNN (Graph Neural Networks) to learn a message-passing algorithm that solves the path inference problem, and using the GRU (Gated Recurrent Unit) to update the historical information. Finally, the actor-learner algorithm is utilized to minimize the sum of the losses of the two parts. Experiment results on three datasets demonstrate the effectiveness and efficiency of our framework. (C) 2020 Elsevier B.V. All rights reserved.

关键词： Knowledge graph ida* algorithm Markov decision process Reinforcement learning Neural network

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A Review On ida* - Iterative deepening algorithm Heuristics Search 6

A Review On IDA* - Iterative deepening algorithm Heuristics ...

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6th International Conference on Trends in Electronics and Informatics (ICOEI)

作者： Sutradhar, Shimul Sharmin, Shabrina Islam, Saiful Daffodil Int Univ Dept CSE Dhaka Bangladesh

ISBN: (纸本)9781665483285;9781665483292

ida* algorithm is a combination of A* and the IDDFS algorithm. This algorithm finds the shortest path. In this paper, we witness parallel computing. Multithreading is one of the most used and common parallel computing techniques. In this paper, I present some ida* optimization based on parallel computing and another one is based on some characteristics. Firstly I present a brief introduction A*, IDDFS, and ida* and the time complexity and growth of those algorithms. Then I discussed 3 optimizations from all the papers I have referenced. Those optimizations are PMida*, A*+ida* and characteristics-based optimization. Then I illustrate the performance measurement table based on A*+ida* algorithm and PMida* visualization. Finally, I compare PMida*, A*+ida*, and characteristics-based optimization optimizations. Among those optimizations, PMida* is the best in terms of parallel computing. The performance of the other two optimizations is also fairly decent.

关键词： Iterative deepening Heuristic CSP ida* algorithm distributed problem solving parallel search techniques admissible tree search

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A Statistical Analysis of Residual Errors in Satellite Remote Sensing Reflectance Data From Oligotrophic Open Oceans

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IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING 2022年 60卷

作者： Chen, Jun He, Xianqiang Quan, Wenting Ma, Lingling Jia, Min Pan, Delu Xi An Jiao Tong Univ Sch Human Settlements & Civil Engn Xian 710049 Peoples R China Minist Nat Resources Inst Oceanog 2 State Key Lab Satellite Ocean Environm Dynam Hangzhou 310012 Peoples R China Ctr Agr Remote Sensing & Econ Corp Shaanxi Meteorol Serv Xian 71000 Peoples R China Chinese Acad Sci Acad Optoelect Key Lab Quantitat Remote Sensing Informat Technol Beijing 100094 Peoples R China

We present a statistical analysis of how residual error from satellite remote sensing reflectance ( $R_{{rs}})$ depends on the environmental factors. Our results indicate that image coverage affects the data quality, and the residual error in high-quality data correlates significantly with the residual error in data heavily contaminated with stray light. Due to imperfectly corrected bidirectional reflectance, we found many residual error anomalies in the covarying relationship between residual error and illumination-observation geometry even though high-quality $R_{{rs}}$ data appeared more homogeneous than low-quality data. Additionally, we found underestimates of $R_{{rs}}$ in very oligotrophic tropical waters, and these residual errors positively covaried with sensor zenith angles at the edge of the scans because of strong atmospheric multi-scattering effects. Furthermore, we found that due to their strong correlation with $R_{{rs}}$ , the spectral relationship of residual errors should be dynamically reinitialized with the image, which is key to an inherent optical properties (IOPs) data processing system (such as idaS) removing the residual errors from the $R_{{rs}}$ data. Doing so, and applying the idaS algorithm, stray-light-contaminated $R_{{rs}}$ was recovered, obtaining comparable results to those achieved considering high-quality measurements. This permits to relax the corresponding quality check for generation of the Level-3 global area coverage $R_{{rs}}$ , largely improving the satellite spatiotemporal coverage and consequently the product accuracy.

关键词： Oceans Image color analysis Sea measurements Satellites Remote sensing MODIS Measurement uncertainty idaS algorithm oligotrophic open ocean remote sensing reflectance residual error

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On Efficient Adjustment in Causal Graphs

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JOURNAL OF MACHINE LEARNING RESEARCH 2020年 21卷

作者： Witte, Janine Henckel, Leonard Maathuis, Marloes H. Didelez, Vanessa Leibniz Inst Prevent Res & Epidemiol BIPS Bremen Germany Univ Bremen Fac Math & Comp Sci Bremen Germany Swiss Fed Inst Technol Seminar Stat Zurich Switzerland

We consider estimation of a total causal effect from observational data via covariate adjustment. Ideally, adjustment sets are selected based on a given causal graph, reflecting knowledge of the underlying causal structure. Valid adjustment sets are, however, not unique. Recent research has introduced a graphical criterion for an 'optimal' valid adjustment set (O-set). For a given graph, adjustment by the O-set yields the smallest asymptotic variance compared to other adjustment sets in certain parametric and non-parametric models. In this paper, we provide three new results on the O-set. First, we give a novel, more intuitive graphical characterisation: We show that the O-set is the parent set of the outcome node(s) in a suitable latent projection graph, which we call the forbidden projection. An important property is that the forbidden projection preserves all information relevant to total causal effect estimation via covariate adjustment, making it a useful methodological tool in its own right. Second, we extend the existing ida algorithm to use the O-set, and argue that the algorithm remains semi-local. This is implemented in the R-package pcalg. Third, we present assumptions under which the O-set can be viewed as the target set of popular non-graphical variable selection algorithms such as stepwise backward selection.

关键词： causal discovery causal inference confounder selection confounding efficiency graphical models ida algorithm model selection sufficient adjustment set

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On efficient adjustment in causal graphs

The Journal of Machine Learning Research

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The Journal of Machine Learning Research 2020年第1期21卷 9956-10000页

作者： Janine Witte Leonard Henckel Marloes H. Maathuis Vanessa Didelez Leibniz Institute for Prevention Research and Epidemiology BIPS Bremen Germany and Faculty of Mathematics and Computer Science University of Bremen Germany Seminar for Statistics ETH Zurich Switzerland

关键词： causal discovery causal inference confounder selection confounding efficiency graphical models ida algorithm model selection sufficient adjustment set

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Measurement of dielectric response of transformer moisture content

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IET SCIENCE MEASUREMENT & TECHNOLOGY 2018年第5期12卷 594-602页

作者： Zhang, Mingze Liu, Ji Qi, Pengshuai Chen, Qingguo Liao, Lilin Chen, Xin Yin, Menghan Harbin Univ Sci & Technol Minist Educ Key Lab Engn Dielectr & Its Applicat Harbin 150080 Heilongjiang Peoples R China Harbin Univ Sci & Technol State Key Lab Breeding Base Dielect Engn Harbin 150080 Heilongjiang Peoples R China Harbin Power Bur State Power Grid Corp Harbin 150080 Heilongjiang Peoples R China

Over a transformer's operational lifetime, the moisture content of its insulation pressboard increases because of the ageing of its internal insulation. Thus, this moisture content becomes an important index for judging the ageing of this insulation. In this study, to analyse the moisture content of a transformer's insulation pressboard using the dielectric response insulation technique, the XY-equivalent model analysis method for classical transformers is combined with a dielectric-constant algorithm for mixed media. In addition, a new method for calculating the moisture content of a pressboard is obtained via cyclic iterative comparison calculations based on the dielectric response translation formula, the temperature, and the material activation energy. The XY-equivalent models of transformers with various proportions are derived under laboratory conditions. The moisture contents of the transformers' insulating pressboards are obtained under the corresponding dielectric loss factor curves by using the proposed moisture content calculation method, which provides a result that is within 4.83% of that provided by the idaX-300 moisture content analysis algorithm, thus demonstrating its validity.

关键词： dielectric measurement moisture measurement power transformer insulation iterative methods dielectric materials dielectric losses transformer moisture content analysis dielectric measurement insulation pressboard dielectric response insulation technique XY-equivalent model analysis method dielectric-constant algorithm cyclic iterative comparison calculation dielectric response translation formula material activation energy dielectric loss factor curve idaX-300 moisture content analysis algorithm

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DIPOR: An ida-based dynamic proof of retrievability scheme for cloud storage systems

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JOURNAL OF NETWORK AND COMPUTER APPLICATIONS 2018年 104卷 97-106页

作者： Fu, Anmin Li, Yuhan Yu, Shui Yu, Yan Zhang, Gongxuan Nanjing Univ Sci & Technol Sch Comp Sci & Engn Nanjing 210094 Jiangsu Peoples R China Guizhou Univ Guizhou Prov Key Lab Publ Big Data Guiyang 550025 Guizhou Peoples R China Deakin Univ Sch Informat Technol Melbourne Vic 3125 Australia

As cloud storage has become more and more ubiquitous, there are a large number of consumers renting cloud storage services. However, as users lose direct control over the data, the integrity and availability of the out sourced data become a big concern for users. Accordingly, how to verify the integrity of stored data and retrieve the availability of the corrupted data has become an urgent problem. Moreover, in most cases, users' data is not always static, but needs to be updated. In this paper, we propose a dynamic proof of retrievability scheme for cloud storage system, named as DIPOR. The DIPOR not only can retrieve the original data of corrupted blocks by using partial healthy data stored in healthy servers, but also support for updating operations of data. Furthermore, the number of forks M our scheme is not fixed, which means we can always look for the optimal forks based on the number of data blocks. In addition, the security analysis indicates that our scheme is provably secure and the performance evaluations show the efficiency of the proposed scheme.

关键词： Cloud storage Proof of retrievability Dynamic ida algorithm

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IPOR: An efficient ida-based proof of retrievability scheme for cloud storage systems

IPOR: An efficient IDA-based proof of retrievability scheme ...

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IEEE International Conference on Communications (ICC) / Wireless Communications Symposium / 3rd Workshop on Optical Wireless Communications (OWC)

作者： Li, Yuhan Fu, Anmin Yu, Yan Zhang, Gongxuan Nanjing Univ Sci & Technol Sch Comp Sci & Engn Nanjing Jiangsu Peoples R China

ISBN: (纸本)9781467389990

With the arrival of big data era, cloud storage has become more ubiquitous. A growing number of consumers remote their data into cloud, as cloud can provide them with ample storage space and powerful computational capacity. However, storing data in cloud means that data is out of their control. How to verify the integrity of stored data and retrieve the corrupted data has become an urgent security problem. In this paper, we propose a new efficient proof of retrievability scheme, named as IPOR, for cloud storage systems. The IPOR not only can verify the integrity of remote data, but also can retrieve the original data of corrupted blocks from the healthy servers with probability 100%. Moreover, IPOR obviously decreases the complexity of data integrity tags and it requires performing a few multiplication and addition operations to retrieve the corrupted data. Therefore, our scheme is much more efficient than the state-of-the-art schemes. In addition, the security analysis indicates that our scheme is provably secure.

关键词： Big data Cloud storage Proof of retrievability ida algorithm

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仿真服务机器人任务规划研究

仿真服务机器人任务规划研究

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作者：王孝贵安徽大学

学位级别：硕士

白从20世纪60年代出现机器人以来,机器人技术已经经历了几十年的快速发展,从最初的传统工业领域向军事、医疗、服务等领域渗透。服务机器人作为机器人家族中的年轻成员,是一种半自主或全自主工作的机器,能够完成各项有益于人类的服务工... 详细信息

白从20世纪60年代出现机器人以来,机器人技术已经经历了几十年的快速发展,从最初的传统工业领域向军事、医疗、服务等领域渗透。服务机器人作为机器人家族中的年轻成员,是一种半自主或全自主工作的机器,能够完成各项有益于人类的服务工作,提高人类的生产和生活质量。随着近年来服务机器人进入家庭生活中,其市场规模不断扩大,已经有越来越多的国家重视机器人技术的研究和发展。服务机器人具有光明的发展前景。在服务机器人发展过程中,机器人任务规划作为一种机器人关键技术一直是研究的热点和难点。本文以机器人大赛中给出的仿真模型描述家庭服务机器人任务规划的问题模型,并以仿真平台为研究平台,研究了机器人任务规划的方法,同时也在仿真系统中测试了每个任务规划方法的规划效果。本文主要的工作如下： 1、将家庭服务机器人任务规划问题转化成回答集编程表示形式,并用iclingo规划器求解规划问题。回答集编程是一种高效的具有知识表示和非单调推理能力的智能规划技术。只要用回答集编程特定的语言描述出所要规划的问题,即可使用规划器求解问题,而不用设计复杂的算法。通过实验分析可知,回答集编程可以高效地求解规划问题的最优解,但是随着问题规模不断扩大时,求解时间也不断增长。 2、针对家庭服务机器人任务规划问题的问题模型,设计了一种求解任务规划的具体策略。这种策略是在详细分析了问题模型之后,将机器人规划的状态空间进行划分,并给出每一种状态下,机器人选择动作的策略。通过实验分析可知,策略求解对每一个任务规划问题都能给出一个解,而且规划问题的时间也很短,但是策略求解不能保证给出的解最优解。此外,策略求解是一种硬编程方式,扩展性和处理约束的能力都不如问答集编程。 3、为了提高求解效率和扩展性,本文提出了用迭代A*算法求解任务规划问题。迭代A*算法是一种迭代加深的A*算法,解决了A*算法空间复杂度高的问题,是一种高效的启发式搜索算法。启发式搜索算法的核心是估值函数,通常估值函数都是针对特定问题而设计的。本文针对机器人任务规划问题,设计了

关键词： home service robot task planning Answer Set Programming lovingstrategy ida*algorithm

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Parallel multithreaded ida* heuristic search: algorithm design and performance evaluation

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INTERNATIONAL JOURNAL OF PARALLEL EMERGENT AND DISTRIBUTED SYSTEMS 2011年第1期26卷 61-82页

作者： Mahafzah, Basel A. Univ Jordan King Abdullah Sch Informat Technol 2 Dept Comp Sci Amman 11942 Jordan

Due to the witnessed prevalence of the commercial multi-core microprocessors, parallel programming becomes a dire need for efficiently using all available hardware resources for one application. One of the parallel programming approaches is multithreading, which has been proved to play a great role in providing sequential computers with virtual parallelisation, yielding faster execution and easy communication. Such advantageous features are provided through creating a dynamic number of concurrent threads at run-time of an application. Based on these facts, this paper presents a parallel multithreaded approach for the well-known iterative deepening A* (ida*) heuristic search algorithm using POSIX threads (Pthreads) and message-passing interface libraries running on 16 dual-core processors. The feasibility of the parallel multithreaded approach is investigated as an alternative for hosting applications requiring intensive graph search. The analytical evaluation and experimental results revealed the improved performance achieved by the proposed parallel multithreaded ida* algorithm.

关键词： heuristic search ida* algorithm multithreaded ida parallel ida performance evaluation

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