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Approximation algorithm for constructing data aggregation trees for wireless sensor networks

中国高等学校学术文摘·计算机科学 2009年第4期3卷 524-534页

作者： Deying LI Jiannong CAO Qinghua ZHU Key Laboratory of Data Engineering and Knowledge Engineering School of InformationRenmin University of ChinaBeijing 100872China Internet and Mobile Computing Lab Department of ComputingHong Kong Polytechnic UniversityHong KongChina

This paper considers the problem of constructing data aggregation trees in wireless sensor networks (WSNs)for a group of sensor nodes to send collected information to a single sink *** data aggregation tree contains the sink node,all the source nodes,and some other non-source *** goal of constructing such a data aggregation tree is to minimize the number of non-source nodes to be included in the tree so as to save *** prove that the data aggregation tree problem is NP-hard and then propose an approximation algorithm with a performance ratio of four and a greedy *** also give a distributed version of the approximation *** simulations are performed to study the performance of the proposed *** results show that the proposed algorithms can find a tree of a good approximation to the optimal tree and has a high degree of scalab.lity.

关键词： WSNs data aggregation tree approximation algorithm distributed algorithm

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Towards annotation-free evaluation of cross-lingual image captioning 2

Towards annotation-free evaluation of cross-lingual image ca...

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2nd ACM International Conference on Multimedia in Asia, MMAsia 2020

作者： Chen, Aozhu Huang, Xinyi Lin, Hailan Li, Xirong Moe Key Lab of Data Engineering and Knowledge Engineering Renmin University of China Beijing China

ISBN: (纸本)9781450383080

Cross-lingual image captioning, with its ability to caption an unlab.led image in a target language other than English, is an emerging topic in the multimedia field. In order to save the precious human resource from re-writing reference sentences per target language, in this paper we make a brave attempt towards annotation-free evaluation of cross-lingual image captioning. Depending on whether we assume the availab.lity of English references, two scenarios are investigated. For the first scenario with the references availab.e, we propose two metrics, i.e., WMDRel and CLinRel. WMDRel measures the semantic relevance between a model-generated caption and machine translation of an English reference using their Word Mover's Distance. By projecting both captions into a deep visual feature space, CLinRel is a visual-oriented cross-lingual relevance measure. As for the second scenario, which has zero reference and is thus more challenging, we propose CMedRel to compute a cross-media relevance between the generated caption and the image content, in the same visual feature space as used by CLinRel. We have conducted a number of experiments to evaluate the effectiveness of the three proposed metrics. The combination of WMDRel, CLinRel and CMedRel has a Spearman's rank correlation of 0.952 with the sum of BLEU-4, METEOR, ROUGE-L and CIDEr, four standard metrics computed using references in the target language. CMedRel alone has a Spearman's rank correlation of 0.786 with the standard metrics. The promising results show high potential of the new metrics for evaluation with no need of references in the target language. © 2021 ACM.

关键词： Semantics

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Region extreme value query in sensor networks

Region extreme value query in sensor networks

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6th International Conference on Fuzzy Systems and knowledge Discovery, FSKD 2009

作者： Wu, Zhongbo Chen, Hong School of Information Renmin University of China Beijing 100872 China MOE Key Lab. of Data Engineering and Knowledge Engineering Beijing 100872 China

ISBN: (纸本)9780769537351

Existing research on extreme value query in wireless sensor networks is mainly focus on finding out sensors with highest metric. Yet in most actually scenarios, people cares more about special network regions than detailed metric of some single nodes. We put forward region extreme query in sensor networks which don't consider a sensor node but a region as query unit. We formally define region extreme value query and discuss how they can be expressed using the SQL. Then we devise a distributed algorithm named DCA for in-network evaluation of region extreme value query in dynamic region, aiming at the minimization of power consumption. Experiments show that DCA has good performance. © 2009 IEEE.

关键词： Sensor nodes

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Reflection on the popularity of MapReduce and observation of its position in a unified big data platform

Reflection on the popularity of MapReduce and observation of...

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14th International Conference on Web-Age Information Management, WAIM 2013

作者： Qin, Xiongpai Qin, Biao Du, Xiaoyong Wang, Shan MOE Key Lab. of Data Engineering and Knowledge Engineering Beijing 100872 China School of Information Renmin University of China Beijing 100872 China

ISBN: (纸本)9783642395260

In recent years MapReduce has risen to be the de-facto tool for big data processing. MapReduce is a disruptive innovation. It has changed the landscape of database market, the landscape of technologies, as well as the landscape of saying power. The article will give a reflection on the popularity of the technique and some observations of its position in a unified big data platform. © 2013 Springer-Verlag.

关键词： MapReduce

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Managing a large shared bank of unstructured data by using free-table

Managing a large shared bank of unstructured data by using f...

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12th International Asia Pacific Web Conference, APWeb 2010

作者： Zhang, Xiao Du, Xiaoyong Chen, Jinchuan Wang, Shan Renming University of China Key Lab. of Data Engineering and Knowledge Engineerging MOE China 59 Zhongguancun Street Beijing China

ISBN: (纸本)9780769540122

This paper presents a reference framework, called BUD, to manage a large shared bank of unstructured data. This paper lists several important issues on managing or maintaining the unstructured data in BUD. BUD stores and manages the ever-growing unstructured data by introducing a novel technique called free-table, which is a conceptual view for endusers and a physical entity maintained by transactional storage manager of BUD. Free-table is cell-oriented but not columnoriented as relational table. It can store various types of unstructured data in cell with different versions. Additionally, we study two cases, VMP and PXRDB, to show that our proposal is feasible and tractable. © 2010 IEEE.

关键词： Digital storage

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Ontology hierarchies matching by lattices alignment

Ontology hierarchies matching by lattices alignment

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2nd International Workshop on Ontology Matching, OM-2007 - Collocated with the 6th International Semantic Web Conference, ISWC-2007 and the 2nd Asian Semantic Web Conference, ASWC-2007

作者： He, Hu Du, Xiaoyong School of Information Renmin University of China 100872 Beijing China Key Lab. of Data and Knowledge Engineering MOE 100872 Beijing China

Ontology matching determines the correspondences between concepts and relations of related ontologies. In this paper, we put forward an ontology hierarchies matching approach based on lattices alignment. The proposed lattice-based matching algorithm can be utilized not only in matching processes between two ontologies, but also in annotation processes between an ontology and its corresponding resources. Experiments on spatiotemporal ontology annotation have been carried out which shown the applicability of the approach.

关键词： Ontology

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Building bilingual ontology from WordNet and Chinese classified thesaurus

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2nd International Conference on knowledge Science, engineering and Management, KSEM 2007

作者： He, Hu Xiaoyong, Du School of Information Renmin University of China 100872 Beijing China Key Lab. of Data and Knowledge Engineering MOE 100872 Beijing China

ISBN: (纸本)9783540767183

Both WordNet and Chinese Classified Thesaurus(CCT) are widely used in information retrieval and management systems. In this paper we propose a novel approach for building bilingual ontologies based on these existing knowledge bases, WordNet and CCT. The bilingual ontology has the merit that contains both domain related and general purpose semantic information coverage from these two complementary knowledge sources. A lattice based similarity measure and assessment algorithm is used for aligning and merging these two knowledge bases. © Springer-Verlag Berlin Heidelberg 2007.

关键词： Ontology

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In-memory join algorithms on GPUs for large-data 21

In-memory join algorithms on GPUs for large-data

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21st IEEE International Conference on High Performance Computing and Communications, 17th IEEE International Conference on Smart City and 5th IEEE International Conference on data Science and Systems, HPCC/SmartCity/DSS 2019

作者： Guo, Chengxin Chen, Hong Key Lab of Data Engineering and Knowledge Engineering of Ministry of Education School of Information Renmin University of China Beijing China

ISBN: (纸本)9781728120584

In traditional databases, join is one of the most computationally expensive operations in query processing. During the past years, GPU has been adopted to improve the performance of join processing because of the features of massive parallelism and high memory bandwidth. Limited by the capacity of GPU memory and the absence of virtual memory management, however, handling the relations that exceed the capacity of the GPU memory is a challenge for GPU-based join algorithms. Because of the high computing throughput provided by GPUs and the low bandwidth of data communication between the CPUs and the GPUs, data have to be partitioned to fit the features of GPUs and to reduce the cost of data transmission. Furthermore, a series of novel techniques have been developed on the GPUs, which can benefit the join algorithms. In this work, we focus on the optimizing of processing join operator on large relations and propose the designs of in-memory hash join and sort-merge join on GPUs. We present the data partition method on the GPUs implemented with a pipeline mechanism. Furthermore, the shuffle instructions and the CUDA streams are applied in our algorithms to best utilize the GPUs. Experimental results indicate that our hash join algorithm delivers up to 1.51X and 1.24X speedup over the state-of-the-art hash join algorithm on CPUs on NVIDIA GTX1080ti-Pascal GPU and TitanV-Volta GPU respectively. For sort-merge join, our algorithm achieves up to 3.52X and 2.21X improvements on the same GPUs respectively compared to the baselines on CPUs. © 2019 IEEE.

关键词： Graphics processing unit

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Parallel hybrid join algorithm on GPU 21

Parallel hybrid join algorithm on GPU

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作者： Guo, Chengxin Chen, Hong Zhang, Feng Li, Cuiping Key Lab of Data Engineering and Knowledge Engineering Ministry of Education School of Information Renmin University of China Beijing China

ISBN: (纸本)9781728120584

In data analytics applications, join is a general and time consuming operation. Optimizing join algorithms can benefit the query processing significantly. The emerging of GPUs provides a massive parallelism solution for improving the performance of the join operation. The hash join (HJ) and sort merge join (SMJ), which are two widely used join algorithms, have been proved effective for efficient join processing on the GPUs. Both algorithms have their own advantages and drawbacks, offering the chance of combining the advantages of HJ and SMJ on GPUs. In processing join operation on GPUs, data need to be transmitted between the CPU and the GPU due to the discrete GPU memory design, which causes performance degradation because of the high PCIe data transfer overhead. As GPUs are becoming more powerful than before, the performance gap between data transmission and GPU execution increases, which makes it even harder to implement an efficient join on GPUs. In this paper, we focus on the optimization of join algorithms on GPUs. We propose the Parallel Hybrid Join algorithm on GPUs(PHYJ) to combine the advantages of HJ and SMJ, and overlap the data communication and GPU execution with a pipeline mechanism. In our evaluation, the PHYJ shows up to 1.72X and 1.55X speedup over the up-to-date HJ and SMJ algorithms respectively on a NVIDIA GTX 1080ti-Pascal GPU. On the TitanV-Volta GPU, up to 1.54X and 1.42X improvements can be achieved over the baseline HJ and SMJ algorithms respectively. © 2019 IEEE.

关键词： Graphics processing unit

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Classifier Belief Optimization for Visual Categorization 27th

Classifier Belief Optimization for Visual Categorization

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27th International Conference on MultiMedia Modeling, MMM 2021

作者： Yang, Gang Li, Xirong Key Lab of Data Engineering and Knowledge Engineering Beijing China School of Information Renmin University of China Beijing China

ISBN: (纸本)9783030678319

Classifier belief represents the confidence of a classifier making judgment about a special instance. Based on classifier belief, we propose an approach to realize classifier belief optimization. Through enriching prior knowledge and thus reducing the scope of candidate classes, our approach improves classification accuracy. A feature perturbation strategy containing an objective optimization is developed to automatically generate lab.led instances. Moreover, we propose a classifier consensus strategy (CCS) for classifier optimization. CCS enables a given classifier to take full advantage of the test data to enrich prior knowledge. Experiments on three benchmark datasets and three classical classifiers justify the validity of the proposed approach. We improve the classification accuracy of a linear SVM by 6%. © 2021, Springer Nature Switzerland AG.

关键词： Image classification

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