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10th International Conference on database and Expert Systems Applications, DEXA 1999

作者： Park, Jang Ho Kim, Kihong Cha, Sang K. Song, Min Seok Lee, Sangho Lee, Juchang Knowledge and Data Engineering Laboratory School of Electrical Engineering Seoul National University Korea Republic of

ISBN: (纸本)3540664483

Newly emerging spatial applications such as the intelligent transportation system require high-performance access to databases. Although research prototypes and spatial extensions on top of commercial DBMSs have been built, the high-performance requirement is difficult to satisfy because most of them employ the traditional disk-based database architecture. With the steadily increasing memory capacity of computer systems, the main-memory database architecture becomes a feasible approach to meeting the requirement, and a few commercial products are developed recently. However, there has been little work on applying the main-memory database to the spatial domain. This paper presents Xmas-SX, a high-performance spatial storage system based on the main-memory database architecture. It provides the core subset of the OpenGIS geometry types, operators, and spatial indexes. Variable-length spatial data are efficiently managed by storing each of them as a sequence of fixed-size fragments. An experiment shows that, compared with a disk-based ODBMS with data fully cached, Xmas-SX shows only 6% better performance for the spatial range query. Before data fully cached, however, the performance gap is much bigger. For the update, Xmas-SX outperforms the ODBMS by more than ten times. © Springer-Verlag Berlin Heidelberg 1999.

关键词： Query processing

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Approximation algorithm for constructing data aggregation trees for wireless sensor networks

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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 scalability.

关键词： WSNs data aggregation tree approximation algorithm distributed algorithm

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A new dynamic hash index for flash-based storage

A new dynamic hash index for flash-based storage

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9th International Conference on Web-Age Information Management, WAIM 2008

作者： Xiang, Li Zhou, Da Meng, Xiaofeng School of Information Renmin University of China Key Laboratory of Data Engineering and Knowledge Engineering MOE

ISBN: (纸本)9780769531854

Compared with traditional magnetic disks, Flash memory has many advantages and has been used as external storage media for a wide spectrum of electronic devices (such as PDA, MP3, Digital Camera and Mobile Phone) in recent years. As the capacity increases and price drops, it looks like a perfect alternative for magnetic disks. However, due to hardware limitations of flash memory, techniques including storage subsystem and indexing originally designed for magnetic disks can not run smoothly in a flash memory without any modification. In this paper we explore problems of indexing flash-resided data and present a new dynamical hash index for flash memory in two schemas. The analysis and experimental results validate the efficiency of our design. © 2008 IEEE.

关键词： Flash memory

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Towards video management over relational database

Towards video management over relational database

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12th International Asia Pacific Web Conference, APWeb 2010

作者： Li, Hui Zhang, Xiao Wang, Shan Du, Xiaoyong School of Information Renmin University of China Key Laboratory of Data Engineering and Knowledge Engineering China

ISBN: (纸本)9780769540122

Video has become popular in our daily life for both professional and consumer applications. Both low level video processing and high level semantic video analysis are critically computational tasks in application domains. Most of current video computing tools are developed for specific analytic tasks, they are lack higher level interoperability with database and treat database merely as a relational data storage engine rather than an analytic platform, which causes inefficient data access and massive amount of data movement. In this paper, we study how to support video data management over relational database, and present our initial solutions of video data storage mechanism, video data access method and efficient video analytics. We also illustrate our ongoing prototype system HybVideo that developed in a novel architecture. It integrates above solutions to tackle the major challenges of providing a platform for both storage and analysis of video data. © 2010 IEEE.

关键词： Information management

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Phase spectrum based automatic ship detection in synthetic aperture radar images

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Journal of Ocean engineering and Science 2021年第2期6卷 185-195页

作者： Miaohui Zhang Baojun Qiao Ming Xin Bo Zhang Henan Key Laboratory of Big Data Analysis and Processing Henan UniversityKaifengChina Institute of Data and Knowledge Engineering Henan UniversityKaifengChina School of Computer Science and Engineering Beihang UniversityBeijingChina

This paper proposes an automatic ship detection approach in Synthetic Aperture Radar(SAR)Images using phase *** proposed method mainly contains two stages:Firstly,sea-land segmentation of SAR Images is one of the key stages for SAR image application such as sea-targets detection and recognition,which are easily detected only in sea *** order to eliminate the influence of land regions in SAR images,a novel land removing method is *** removing method employs a Harris corner detector to obtain some image patches belonging to land,and the probability density function(PDF)of land area can be estimated by these ***,an appropriate land segmentation threshold is accordingly ***,an automatic ship detector based on phase spectrum is *** proposed detector is free from various idealized assumptions and can accurately detect ships in SAR *** results demonstrate the efficiency of the proposed ship detection algorithm in diversified SAR images.

关键词： Ship detection saliency detection phase spectrum sea-land segmentation

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RJMIM: A new feature selection method based on joint mutual information

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Revista de la Facultad de Ingenieria 2016年第4期31卷 59-69页

作者： Peng, Liwen Liu, YongGuo Knowledge and Data Engineering Laboratory of Chinese Medicine School of Information and Software Engineering University of Electronic Science and Technology of China Chengdu610054 China

Feature selection based on information theory plays an important role in classification algorithm due to its computational efficiency and independent from classification method. It is widely used in many application areas like data mining, bioinformatics and machine learning. But drawbacks of these methods are the neglect of the feature interaction and overestimation of features significance due to the limitations of goal functions criterion. To address this problem, we proposed a new feature goal function RJMIM. The method employed joint mutual information and information interaction, which alleviates the shortcomings of overestimation of the feature significance as demonstrated both theoretically and experimentally. The experiments conducted to verify the performance of the proposed method, it compared with four well-known feature selection methods use three publically available datasets from UCI. The average classification accuracy and C4.5 classifier is used to assess the effectiveness of RJMIM method.

关键词： Classification (of information)

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MacroTrend: A Write-Efficient Cache Algorithm for NVM-Based Read Cache

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Journal of Computer Science & Technology 2022年第1期37卷 207-230页

作者： Ning Bao Yun-Peng Chai Xiao Qin Chuan-Wen Wang Key Laboratory of Data Engineering and Knowledge Engineering Ministry of EducationBeijing 100872China School of Information Renmin University of ChinaBeijing 100872China Samuel Ginn College of Engineering Auburn UniversityAlabama 36830U.S.A.

The future storage systems are expected to contain a wide variety of storage media and layers due to the rapid development of NVM(non-volatile memory)*** NVM-based read caches,many kinds of NVM devices cannot stand frequent data updates due to limited write endurance or high energy consumption of ***,traditional cache algorithms have to update cached blocks frequently because it is difficult for them to predict long-term popularity according to such limited information about data blocks,such as only a single value or a queue that reflects frequency or *** this paper,we propose a new MacroTrend(macroscopic trend)prediction method to discover long-term hot blocks through blocks'macro trends illustrated by their access count *** then a new cache replacement algorithm is designed based on the MacroTrend prediction to greatly reduce the write amount while improving the hit *** conduct extensive experiments driven by a series of real-world traces and find that compared with LRU,MacroTrend can reduce the write amounts of NVM cache devices significantly with similar hit ratios,leading to longer NVM lifetime or less energy consumption.

关键词： non-volatile memory(NVM) solid state disk(SSD) cache endurance

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Gender Disparity in Expressed Emotions within Health-Related Online Support Groups

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Proceedings of the Association for Information Science and Technology 2021年第1期58卷 883-885页

作者： Zhao, Yuehua Wang, Hao Deng, Sanhong Chen, Ye Nanjing University Jiangsu Key Laboratory of Data Engineering and Knowledge Service Nanjing China Central China Normal University Wuhan China

Online support groups offer a new way to users to communicate with others regarding certain health issues. Taking autism-related support groups on Facebook as an example, we examine whether the expressed emotions differ between female and male users in online health-related support groups and whether such gender disparity varied based on the topics of the groups. Experimental results reveal a significant gender difference of expressed emotions in the groups. We find that female users tended to express more positive emotions in the group discussions than the male group members did. In addition, users appeared to express different sentiments within the groups focused on various topics. Male users tend to convey more negative emotions in the group that related to treatment, while female users were more positive when posted in the research-related group than male users were. This study is beneficial for tracking and moderating the emotional environment in online support groups. 84 Annual Meeting of the Association for Information Science & Technology | Oct. 29 – Nov. 3, 2021 | Salt Lake City, UT. Author(s) retain copyright, but ASIS&T receives an exclusive publication license.

关键词： Sentiment analysis

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PULASki: Learning inter-rater variability using statistical distances to improve probabilistic segmentation

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Medical Image Analysis 2025年 103卷 103623页

作者： Chatterjee, Soumick Gaidzik, Franziska Sciarra, Alessandro Mattern, Hendrik Janiga, Gábor Speck, Oliver Nürnberger, Andreas Pathiraja, Sahani Data and Knowledge Engineering Group Faculty of Computer Science Otto von Guericke University Magdeburg Germany Genomics Research Centre Human Technopole Milan Italy Laboratory of Fluid Dynamics and Technical Flows Otto von Guericke University Magdeburg Germany Department of Biomedical Magnetic Resonance Faculty of Natural Sciences Otto von Guericke University Magdeburg Germany MedDigit Department of Neurology Medical Faculty University Hospital Magdeburg Germany German Centre for Neurodegenerative Disease Magdeburg Germany Centre for Behavioural Brain Sciences Magdeburg Germany School of Mathematics & Statistics UNSW Sydney Australia

In the domain of medical imaging, many supervised learning based methods for segmentation face several challenges such as high variability in annotations from multiple experts, paucity of labelled data and class imbalanced datasets. These issues may result in segmentations that lack the requisite precision for clinical analysis and can be misleadingly overconfident without associated uncertainty quantification. This work proposes the PULASki method as a computationally efficient generative tool for biomedical image segmentation that accurately captures variability in expert annotations, even in small datasets. This approach makes use of an improved loss function based on statistical distances in a conditional variational autoencoder structure (Probabilistic UNet), which improves learning of the conditional decoder compared to the standard cross-entropy particularly in class imbalanced problems. The proposed method was analysed for two structurally different segmentation tasks (intracranial vessel and multiple sclerosis (MS) lesion) and compare our results to four well-established baselines in terms of quantitative metrics and qualitative output. These experiments involve class-imbalanced datasets characterised by challenging features, including suboptimal signal-to-noise ratios and high ambiguity. Empirical results demonstrate the PULASKi method outperforms all baselines at the 5% significance level. Our experiments are also of the first to present a comparative study of the computationally feasible segmentation of complex geometries using 3D patches and the traditional use of 2D slices. The generated segmentations are shown to be much more anatomically plausible than in the 2D case, particularly for the vessel task. Our method can also be applied to a wide range of multi-label segmentation tasks and is useful for downstream tasks such as hemodynamic modelling (computational fluid dynamics and data assimilation), clinical decision making, and treatment planning. © 2

关键词： Image segmentation

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Larger, Cheaper, but Faster: SSD-SMR hybrid storage boosted by a new SMR-oriented cache framework 33

Larger, Cheaper, but Faster: SSD-SMR hybrid storage boosted ...

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33rd International Conference on Massive Storage Systems and Technology, MSST 2017

作者： Wang, Chunling Wang, Dandan Chai, Yupeng Wang, Chuanwen Sun, Diansen Key Laboratory of Data Engineering and Knowledge Engineering School of Information Renmin University of China Beijing China

By utilizing the new Shingled Magnetic Recording (SMR) technique, the emerging SMR disks achieve higher storage density and lower costs. Together with Flash-based SSDs, SMR disks can be used to construct a new hybrid storage system that is larger, but cheaper than the widely used conventional diskbased storage systems. It is appropriate for the fast growing big data applications which have strict requirements on both capacity and cost, e.g., the scientific computing in the fields of meteorology and astronomy. However, the most serious challenge of the SSD-SMR hybrid storage lies in its weak fine-grained random write performance caused by the write amplification in SMR disks, especially when I/Os are spread randomly across the Logical Block Address (LBA) range of the entire disk. Traditional cache algorithms like LRU usually lead to tens of or even hundreds of times more data written into magnetic plates than the original requests, thus resulting in poor I/O performance, because they do not consider and limit the LBA distribution of the eviction victims at all. Therefore, the cache algorithms for SSD-SMR hybrid storage systems should take this new dimension into account except for the data popularity. In this paper, we propose a new SMR-oriented cache framework, i.e., Partially Open Region for Eviction (PORE), which restricts the LBA range of evicted data from SSD caches appropriately to promote the overall performance of the hybrid storage by making a better tradeoff between the cached data popularity and the SMR write amplification. The experiments based on real-world traces reveal that PORE can boost the SSD-SMR hybrid storage performance by a factor of 3.26∼10.2 with only a 2% SSD cache compared with a conventional disk-based storage on average, while the hybrid storage coupled with LRU is slower than the conventional storage sometimes. PORE makes the hybrid storage much faster than traditional storage besides the advantages on capacity and cost. © 33rd Internati

关键词： Hard disk storage

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