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Enabling Efficient NVM-Based Text Analytics without Decompression

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Enabling Efficient NVM-Based Text Analytics without Decompre...

International Conference on data engineering

作者： Xiaokun Fang Feng Zhang Junxiang Nong Mingxing Zhang Puyun Hu Yunpeng Chai Xiaoyong Du Key Laboratory of Data Engineering and Knowledge Engineering (MOE) and School of Information Renmin University of China Department of Computer Science and Engineering Tsinghua University

ISBN: (数字)9798350317152

ISBN: (纸本)9798350317169

Text analytics directly on compression (TADOC) is a promising technology designed for handling big data analytics. However, a substantial amount of DRAM is required for high performance, which limits its usage in many important scenarios where the capacity of DRAM is limited, such as memory-constrained systems. Non-volatile memory (NVM) is a novel storage technology that combines the advantage of reading per-formance and byte addressability of DRAM with the durability of traditional storage devices like SSD and HDD. Unfortunately, no research demonstrates how to use NVM to reduce DRAM utilization in compressed data analytics. In this paper, we propose N-TADOC, which substitutes DRAM with NVM while maintaining TADOC's analytics performance and space savings. Utilizing an NVM block device to reduce DRAM utilization presents two challenges, including poor data locality in traversing datasets and auxiliary data structure reconstruction on NVM. We develop novel designs to solve these challenges, including a pruning method with NVM pool management, bottom-up upper bound estimation, correspondent data structures, and persistence strategy at different levels of cost. Experimental results show that on four real-world datasets, N-TADOC achieves 2.04× performance speedup compared to the processing directly on the uncompressed data and 70.7% DRAM space saving compared to the original TADOC.

关键词： Performance evaluation Upper bound data analysis Costs Nonvolatile memory Random access memory Estimation

Rethinking data-Free Quantization as a Zero-Sum Game

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arXiv 2023年

作者： Qian, Biao Wang, Yang Hong, Richang Wang, Meng Key Laboratory of Knowledge Engineering with Big Data Ministry of Education School of Computer Science and Information Engineering Hefei University of Technology China

data-free quantization (DFQ) recovers the performance of quantized network (Q) without accessing the real data, but generates the fake sample via a generator (G) by learning from full-precision network (P) instead. However, such sample generation process is totally independent of Q, specialized as failing to consider the adaptability of the generated samples, i.e., beneficial or adversarial, over the learning process of Q, resulting into non-ignorable performance loss. Building on this, several crucial questions — how to measure and exploit the sample adaptability to Q under varied bit-width scenarios? how to generate the samples with desirable adaptability to benefit the quantized network? — impel us to revisit DFQ. In this paper, we answer the above questions from a game-theory perspective to specialize DFQ as a zero-sum game between two players — a generator and a quantized network, and further propose an Adaptability-aware Sample Generation (AdaSG) method. Technically, AdaSG reformulates DFQ as a dynamic maximization-vs-minimization game process anchored on the sample adaptability. The maximization process aims to generate the sample with desirable adaptability, such sample adaptability is further reduced by the minimization process after calibrating Q for performance recovery. The Balance Gap is defined to guide the stationarity of the game process to maximally benefit Q. The theoretical analysis and empirical studies verify the superiority of AdaSG over the state-of-the-arts. Our code is available at https://***/hfutqian/AdaSG. Copyright © 2023, The Authors. All rights reserved.

关键词： Game theory

Ontology-based Categorization of Web Search Results Using YAGO

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Ontology-based Categorization of Web Search Results Using YA...

The Second International Joint Conference on Computational Science and Optimization(CSO 2009)(2009 国际计算科学与优化会议)

作者： Anjian Ren Xiaoyong Du Puwei Wang Key Laboratory of Data Engineering and Knowledge Engineering Ministry of Education China School of Information Renmin University of China Beijing 100782 China

One of the major limitations of current search engines is that users could not quickly locate what they want if the input query is too general. Some existing techniques try to cluster web search results into groups so as to user's quick browsing. In this paper, we present a new approach to categorize the web search results by using YAGO ontology. It utilizes the YAGO ontology to automatically generate categories for the user's specific query and classify the search results into appropriate categories. Our experimental results indicate that our method is feasible and effectiveness.

关键词： Ontologies Web search Feedback Image retrieval Information retrieval Image databases Humans Set theory Information systems Radio frequency

ParaCube: A Scalable OLAP Model Based on Distributed Aggregate Computing with Sibling Cubes

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ParaCube: A Scalable OLAP Model Based on Distributed Aggrega...

International Asia-Pacific Web Conference (APWEB)

作者： Yansong Zhang Shan Wang Wei Huang Key Laboratory of Ministry of Education of Data Engineering and Knowledge Engineering Beijing China School of Information Renmin University of China Beijing China

The requirements of OLAP applications increase rapidly by dramatically increased data volume, users, query volume and query complexity. The requirement for shortening update period in data warehouse is another crucial factor for a scalable OLAP application. In this paper, we propose a scalable OLAP prototype to support the query processing with increasing data volume by distributing the whole fact tuples to multiple servers to construct a set of sibling cubes which can be merged together to obtain the whole cube. We employ a light weight distribution policy with fully duplicated dimension tables in each sibling server on the observation of very low proportion of space cost for dimension tables. OLAP query with distributed aggregate functions can be transformed into queries to be performed parallel in sibling servers. For non-distributed computing aggregate functions, such as median, the optimized median aggregate computing algorithm is proposed to reduce transmission volume between servers while computing the global median values. We also present a three-level framework in data warehouse to meet the requirement of shorter update period in "operational business intelligence". An asynchronous tunnel model is proposed to reduce update latency by pre-fetching updated tuples to OLAP processing server. Finally, we set up prototype system ParaCube to evaluate performance in SN (shared-nothing) system and multi-core platforms.

关键词： Aggregates Distributed computing Concurrent computing data warehouses Merging Application software Prototypes Query processing Acceleration Material storage

Adaptive data-Free Quantization

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arXiv 2023年

data-free quantization (DFQ) recovers the performance of quantized network (Q) without accessing the original data, but generates the fake sample via a generator (G) by learning from full-precision network (P), which, however, is totally independent of Q, overlooking the adaptability of the knowledge from generated samples, i.e., informative or not to the learning process of Q, resulting into the overflow of generalization error. Building on this, several critical questions - how to measure the sample adaptability to Q under varied bit-width scenarios? how to generate the samples with large adaptability to improve Q's generalization? whether the largest adaptability is the best? To answer the above questions, in this paper, we propose an Adaptive data-Free Quantization (AdaDFQ) method, which revisits DFQ from a zero-sum game perspective upon the sample adaptability between two players - a generator and a quantized network. Following this viewpoint, we further define the disagreement and agreement samples to form two boundaries, where the margin is optimized to address the over-and-under fitting issues, so as to generate the samples with adaptive adaptability to Q. Our AdaDFQ reveals: 1) the largest adaptability is NOT the best for sample generation to benefit Q's generalization;2) the knowledge of the generated sample should not be informative to Q only, but also related to the category and distribution information of the training data for P. The theoretical and empirical analysis validate the advantages of AdaDFQ over the state-of-the-arts. Our code is available at https://***/hfutqian/AdaDFQ. Copyright © 2023, The Authors. All rights reserved.

关键词： Machine learning

Query-Aware Complex Object Buffer Management in XML Information Retrieval

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Query-Aware Complex Object Buffer Management in XML Informat...

International Asia-Pacific Web Conference (APWEB)

作者： Qiushi Li Qiuyue Wang Shan Wang Key Laboratory of Ministry of Education of Data Engineering and Knowledge Engineering Beijing China School of Information Renmin University of China Beijing China

In this paper, we analyse the data access characteristics of a typical XML information retrieval system and propose a new query aware buffer replacement algorithm based on prediction of Minimum Reuse Distance (MRD for short). The algorithm predicts an object's next reference distance according to the retrieval system's running status and replaces the objects that have maximum reuse distances. The factors considered in the replacement algorithm include the access frequency, creation cost, and size of objects, as well as the queries being executed. By taking into account the queries currently running or queuing in the system, MRD algorithm can predict more accurately the reuse distances of index data objects.

关键词： Information management XML Information retrieval Tree data structures Indexing Prediction algorithms Algorithm design and analysis Frequency data analysis Information analysis

Biggy: An implementation of unified framework for big data management system

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arXiv 2018年

作者： Wu, Yao Guan, Henan Key Laboratory of Data Engineering Knowledge Engineering of Ministry of Education Beijing China School of Information Renmin University of China Beijing China

Various tools, softwares and systems are proposed and implemented to tackle the challenges in big data on different emphases, e.g., data analysis, data transaction, data query, data storage, data visualization, data privacy. In this paper, we propose datar, a new prospective and unified framework for Big data Management System (BDMS) from the point of system architecture by leveraging ideas from mainstream computer structure. We introduce five key components of datar by reviewing the current status of BDMS. datar features with configuration chain of pluggable engines, automatic dataflow on job pipelines, intelligent self-driving system management and interactive user interfaces. Moreover, we present biggy as an implementation of datar with manipulation details demonstrated by four running examples. Evaluations on efficiency and scalability are carried out to show the performance. Our work argues that the envisioned datar is a feasible solution to the unified framework of BDMS, which can manage big data pluggablly, automatically and intelligently with specific functionalities, where specific functionalities refer to input, storage, computation, control and output of big data. Copyright © 2018, The Authors. All rights reserved.

关键词： Big data

HelPal: A Search System for Mobile Crowd Service

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arXiv 2017年

作者： Wu, Yao Wu, Tianzhen Xiong, Ziyi Wu, Yuncheng Chen, Hong Li, Cuiping Zhang, Xiaoying Key Laboratory of Data Engineering and Knowledge Engineering of Ministry of Education Beijing China School of Information Renmin University of China Beijing China

Proliferation of ubiquitous mobile devices makes location based services prevalent. Mobile users are able to volunteer as providers of specific services and in the meanwhile to search these services. For example, drivers may be interested in tracking available nearby users who are willing to help with motor repair or are willing to provide travel directions or first aid. With the diffusion of mobile users, it is necessary to provide scalable means of enabling such users to connect with other nearby users so that they can help each other with specific services. Motivated by these observations, we design and implement a general location based system HelPal for mobile users to provide and enjoy instant service, which is called mobile crowd service. In this demo, we introduce a mobile crowd service system featured with several novel techniques. We sketch the system architecture and illustrate scenarios via several cases. Demonstration shows the user-friendly search interface for users to conveniently find skilled and qualified nearby service providers. Copyright © 2017, The Authors. All rights reserved.

关键词： Location based services

VANETs-Based Real-time Traffic data Dissemination

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VANETs-Based Real-time Traffic Data Dissemination

2010 IEEE International Conference Conferenhce on Wireless Communications,Networking and Information Security(2010 IEEE 无线通信、网络技术与信息安全国际会议 WCNIS)

作者： Wenping Chen Department of Computer Science??Renmin University of China Beijing Key Laboratory of Data Engineering and Knowledge Engineering (Renmin University of China) MOE

ISBN: (纸本)9781424458509

Traffic congestion is a very serious problem in large cities. With the number of vehicles increasing rapidly, especially in cities whose economy is booming, the situation is getting even worse. In this paper, by leveraging the techniques of Vehicular Ad hoc Networks (VANETs) we present a real-time abnormal traffic data dissemination protocol. Specifically, all vehicles running on the same road segment are regarded as a cluster to generate traffic message about this segment. To reduce communication cost, only abnormal traffic data is issued and spread to nearby road segments. By employing event-driven and period combined mechanism, the abnormal traffic messages are disseminated to the vehicles that probably need the messages in time. We propose a distance dependent forwarder selection method to disseminate traffic message. When transmitted inside a cluster, messages are forwarded along the segment from one end to the other based on the least hops principle;while transmitted among clusters, messages are transmitted in epidemic routing mode, which ensure the fast and reliable dissemination. To evaluate the performance of our protocol, we use the real traffic data of Beijing at peak hour. The simulation results demonstrate that our protocol is feasible and efficient for metropolitan-size city.

关键词： vehicular networks traffic real-time