• Title/Summary/Keyword: Query Index

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A Study of Designing the Knowledge Base System for the Query Extension by Index File (색인파일 기반의 질의어 확장용 지식베이스 구축에 관한 연구)

  • Seo, Whee
    • Journal of Korean Library and Information Science Society
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    • v.40 no.2
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    • pp.139-159
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    • 2009
  • This study is to develop knowledge base system for query extension to the user oriented information retrieval. This study has survey the theories of the concept-based information retrieval method and statistic based information retrieval method. In the construction method of knowledge base, the common hypothesis is that the emergence of related term is the frequency of simultaneous emergence of a set of documents. Using the subject index file algorithms and the 'and' operator of boolean logic based on this hypothesis, this study builds the knowledge base. In this research experiment, a subject of knowledge base is education. Using the book of the Introduction to Education, two experimental knowledge base systems is constructed by the different indexing method. One system has constructed by controlled language indexing method, and another system has constructed by natural language indexing method. The performance of two knowledge base system is evaluated.

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Indexing and Storage Schemes for Keyword-based Query Processing over Semantic Web Data (시맨틱 웹 데이터의 키워드 질의 처리를 위한 인덱싱 및 저장 기법)

  • Kim, Youn-Hee;Shin, Hye-Yeon;Lim, Hae-Chull;Chong, Kyun-Rak
    • Journal of the Korea Society of Computer and Information
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    • v.12 no.5
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    • pp.93-102
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    • 2007
  • Metadata and ontology can be used to retrieve related information through the inference mure accurately and simply on the Semantic Web. RDF and RDF Schema are general languages for representing metadata and ontology. An enormous number of keywords on the Semantic Web are very important to make practical applications of the Semantic Web because most users prefer to search with keywords. In this paper, we consider a resource as a unit of query results. And we classily queries with keyword conditions into three patterns and propose indexing techniques for keyword-search considering both metadata and ontology. Our index maintains resources that contain keywords indirectly using conceptual relationships between resources as well as resources that contain keywords directly. So, if user wants to search resources that contain a certain keyword, all resources are retrieved using our keyword index. We propose a structure of table for storing RDF Schema information that is labeled using some simple methods.

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Improving Join Performance for SPARQL Query Processing in the Clouds (클라우드에서 SPARQL 질의 처리를 위한 조인 성능 향상)

  • Choi, Gyu-Jin;Son, Yun-Hee;Lee, Kyu-Chul
    • Journal of KIISE
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    • v.43 no.6
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    • pp.700-709
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    • 2016
  • Recently, with the rapid growth of LOD (Linked Open Data) existing methods based on a single machine have limitation in performance. Existing solutions use distributed framework such as Mapreduce in order to improve the performance. However, the MapReduce framework for processing SPARQL queries involves multiple MapReduce jobs and additional costs incurred. In addition, the problem of unnecessary data processing arises. In this study, we proposed a method to reduce the number of MapReduce jobs during SPARQL query processing and join indexes based on Bitmap for minimizing the costs of processing unnecessary data.

BADA-$IV/I^2R$: Design & Implementation of an Efficient Content-based Image Retrieval System using a High-Dimensional Image Index Structure (바다-$IV/I^2R$: 고차원 이미지 색인 구조를 이용한 효율적인 내용 기반 이미지 검색 시스템의 설계와 구현)

  • Kim, Yeong-Gyun;Lee, Jang-Seon;Lee, Hun-Sun;Kim, Wan-Seok;Kim, Myeong-Jun
    • The Transactions of the Korea Information Processing Society
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    • v.7 no.2S
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    • pp.678-691
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    • 2000
  • A variety of multimedia applications require multimedia database management systems to manage multimedia data, such as text, image, and video, as well as t support content-based image or video retrieval. In this paper we design and implement a content-based image retrieval system, BADA-IV/I$^2$R(Image Information Retrieval), which is developed based on BADA-IV multimedia database management system. In this system image databases can be efficiently constructed and retrieved with the visual features, such as color, shape, and texture, of image. we extend SQL statements to define image query based on both annotations and visual features of image together. A high-dimensional index structure, called CIR-tree, is also employed in the system to provide an efficient access method to image databases. We show that BADA-IV/I$^2$R provides a flexible way to define query for image retrieval and retrieves image data fast and effectively: the effectiveness and performance of image retrieval are shown by BEP(Bull's Eye Performance) that is used to measure the retrieval effectiveness in MPEG-7 and comparing the performance of CIR-tree with those of X-tree and TV-tree, respectively.

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An Index Splitting Technique for Numerous Sensor Data Archiving (대용량 센서 데이터 아카이빙을 위한 색인 분할 기법)

  • Cho, Dae-Soo
    • Journal of Korea Spatial Information System Society
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    • v.9 no.1
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    • pp.31-43
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    • 2007
  • Sensor data have the characteristics such as numerous and continuous data. Therefore, it is required to develop an index which could retrieve a specific sensor data efficiently from numerous sensed data. The index should have an efficient delete operation for the past data to support the data archiving. In this paper, we have proposed and implemented an index splitting technique to support the sensor data archiving. These splitted indexes compose of a virtual index (that is, index management component), which is shown as single tree from outside. Experimental results show that in the case of 100,000 insert operations the splitted index performs 8% better than the traditional TB-tree maximumly. And the splitted index outperforms TB-tree with retrieving queries when the region of query is small and the size of time domain is large.

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Performance Evaluation of Fixed-Grid File Index on NAND Flash Memory (NAND 플래쉬메모리에서 고정그리드화일 색인의 성능 평가)

  • Kim, Dong-Hyun
    • The Journal of the Korea institute of electronic communication sciences
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    • v.10 no.2
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    • pp.275-282
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    • 2015
  • Since a NAND-flash memory is able to keep data during electricity-off and has small cost to store data per bytes, it is widely used on hand-held devices. It is necessary to use an index in order to process mass data effectively on the flash memory. However, since the flash memory requires high cost for a write operation and does not support an overwrite operation, it is possible to reduce the performance of the index when the disk based index is exploited. In this paper, we implement the fixed grid file index and evaluate the performance of the index on various conditions. To do this, we measure the average processing time by the ratio of query operations and update operations. We also the compare the processing times of the flash memory with those of the magnetic disk.

Distributed Indexing Methods for Moving Objects based on Spark Stream

  • Lee, Yunsou;Song, Seokil
    • International Journal of Contents
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    • v.11 no.1
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    • pp.69-72
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    • 2015
  • Generally, existing parallel main-memory spatial index structures to avoid the trade-off between query freshness and CPU cost uses light-weight locking techniques. However, still, the lock based methods have some limits such as thrashing which is a well-known problem in lock based methods. In this paper, we propose a distributed index structure for moving objects exploiting the parallelism in multiple machines. The proposed index is a lock free multi-version concurrency technique based on the D-Stream model of Spark Stream. The proposed method exploits the multiversion nature of D-Stream of Spark Streaming.

A Hybrid Index of Voronoi and Grid Partition for NN Search

  • Seokjin Im
    • International journal of advanced smart convergence
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    • v.12 no.1
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    • pp.1-8
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    • 2023
  • Smart IoT over high speed network and high performance smart devices explodes the ubiquitous services and applications. Nearest Neighbor(NN) query is one of the important type of queries that have to be supported for ubiquitous information services. In order to process efficiently NN queries in the wireless broadcast environment, it is important that the clients determine quickly the search space and filter out NN from the candidates containing the search space. In this paper, we propose a hybrid index of Voronoi and grid partition to provide quick search space decision and rapid filtering out NN from the candidates. Grid partition plays the role of helping quick search space decision and Voronoi partition providing the rapid filtering. We show the effectiveness of the proposed index by comparing the existing indexing schemes in the access time and tuning time. The evaluation shows the proposed index scheme makes the two performance parameters improved than the existing schemes.

The Method to Process Nearest Neighbor Queries Using an Optimal Search Distance (최적탐색거리를 이용한 최근접질의의 처리 방법)

  • Seon, Hwi-Joon;Hwang, Bu-Hyun;Ryu, Keun-Ho
    • The Transactions of the Korea Information Processing Society
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    • v.4 no.9
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    • pp.2173-2184
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    • 1997
  • Among spatial queries handled in spatial database systems, nearest neighbor queries to find the nearest spatial object from the given locaion occur frequently. The number of searched nodes in an index must be minimized in order to increase the performance of nearest neighbor queries. An Existing approach considered only the processing of an nearest neighbor query in a two-dimensional search space and could not optimize the number of searched nodes accurately. In this paper, we propose the optimal search distance and prove its properties. The proposed optimal search distance is the measurement of a new search distance for accurately selecting the nodes which will be searched in processing nearest neighbor queries. We present an algorithm for processing the nearest neighbor query by applying the optimal search distance to R-trees and prove that the result of query processing is correcter than the existing approach.

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Spatial Statistic Data Release Based on Differential Privacy

  • Cai, Sujin;Lyu, Xin;Ban, Duohan
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.13 no.10
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    • pp.5244-5259
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    • 2019
  • With the continuous development of LBS (Location Based Service) applications, privacy protection has become an urgent problem to be solved. Differential privacy technology is based on strict mathematical theory that provides strong privacy guarantees where it supposes that the attacker has the worst-case background knowledge and that knowledge has been applied to different research directions such as data query, release, and mining. The difficulty of this research is how to ensure data availability while protecting privacy. Spatial multidimensional data are usually released by partitioning the domain into disjointed subsets, then generating a hierarchical index. The traditional data-dependent partition methods need to allocate a part of the privacy budgets for the partitioning process and split the budget among all the steps, which is inefficient. To address such issues, a novel two-step partition algorithm is proposed. First, we partition the original dataset into fixed grids, inject noise and synthesize a dataset according to the noisy count. Second, we perform IH-Tree (Improved H-Tree) partition on the synthetic dataset and use the resulting partition keys to split the original dataset. The algorithm can save the privacy budget allocated to the partitioning process and obtain a more accurate release. The algorithm has been tested on three real-world datasets and compares the accuracy with the state-of-the-art algorithms. The experimental results show that the relative errors of the range query are considerably reduced, especially on the large scale dataset.