• Title/Summary/Keyword: Index Update

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Cost Model of Index Structures for Moving Objects Databases (이동체 데이터베이스를 위한 색인 구조의 비용모델)

  • Jun, Bong-Gi
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.11 no.3
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    • pp.523-531
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    • 2007
  • In this paper, we are going to develop a newly designed indexing scheme which is compatible to manage the moving objects and propose a cost model of the scheme. We propose a dynamic hashing index that insertion/delete costs are low. The dynamic hashing structure is that apply dynamic hashing techniques to combine a hash and a tree to a spatial index. We analyzed the dynamic index structure and the cost model by the frequent position update of moving objects and verified through a performance assessment experiment. The results of our extensive experiments show that the newly proposed indexing schemes(Dynamic Hashing Index) are much more efficient than the traditional the fixed grid and R-tree.

A Compressed Hot-Cold Clustering to Improve Index Operation Performance of Flash Memory-SSD Systems (플래시메모리-SSD의 인덱스 연산 성능 향상을 위한 압축된 핫-콜드 클러스터링 기법)

  • Byun, Si-Woo
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.11 no.1
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    • pp.166-174
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    • 2010
  • SSDs are one of the best media to support portable and desktop computers' storage devices. Their features include non-volatility, low power consumption, and fast access time for read operations, which are sufficient to present flash memories as major database storage components for desktop and server computers. However, we need to improve traditional index management schemes based on B-Tree due to the relatively slow characteristics of flash memory operations, as compared to RAM memory. In order to achieve this goal, we propose a new index management scheme based on a compressed hot-cold clustering called CHC-Tree. CHC-Tree-based index management improves index operation performance by dividing index nodes into hot or cold segments and compressing pointers and keys in the index nodes and clustering the hot or cold segments. The offset compression techniques using unused free area in cold index node lead to reduce the number of slow erase operations in index node insert/delete processes. Simulation results show that our scheme significantly reduces the write and erase operation overheads, improving the index search performance of B-Tree by up to 26 percent, and the index update performance by up to 23 percent.

Efficient Dynamic Index Structure for SSD (SPM) (SSD에 적합한 동적 색인 저장 구조 : SPM)

  • Jin, Du-Seok;Kim, Jin-Suk;You, Beom-Jong;Jung, Hoe-Kyung
    • The Journal of the Korea Contents Association
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    • v.10 no.2
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    • pp.54-62
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    • 2010
  • Inverted index structures have become the most efficient data structure for high performance indexing of large text collections, especially online index maintenance, In-Place and merge-based index structures are the two main competing strategies for index construction in dynamic search environments. In the above-mentioned two strategies, a contiguity of posting information is the mainstay of design for online index maintenance and query time. Whereas with the emergence of new storage device(SSD, SCRAM), those do not consider a contiguity of posting information in the design of index structures because of its superiority such as low access latency and I/O throughput speeds. However, SSD(Solid State Drive) is not well suited for traditional inverted structures due to the poor random write throughput in practical systems. In this paper, we propose the new efficient online index structure(SPM) for SSD that significantly reduces the query time and improves the index maintenance performance.

An Efficient Dynamic Indexing Model for Various Structure Retrievals of XML Documents (XML 문서의 다양한 구조 검색을 위한 효율적인 동적 색인 모델)

  • 신승호;손충범;강형일;유재수
    • Journal of KIISE:Databases
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    • v.31 no.1
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    • pp.48-60
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    • 2004
  • XML documents consist of elements that are basic units of information. When the structure of XML documents is changed dynamically, we need to update structure information efficiently without changing the information of the index structure for fast retrieval. In this paper, we propose a dynamic indexing model scheme that updates the index structure in real time as the structure of XML documents is changed by insertion and deletion of elements. Our dynamic indexing model consists of a structure information representation method and a dynamic index structure. The structure information representation method supports various types of structure retrievals. Our dynamic index structure processes various structural queries efficiently. We show through various experiments that our method outperforms existing ones in processing various types of queries such as content based queries, structural queries and hybrid queries.

Development of Safety Assessment Indicators and Facility Management System for Crime Prevention - A Case Study of Park -

  • Lee, Su-Ji;Lee, Seung-Su;Song, Ki-Sung;Hwang, Jung-Rae
    • Journal of the Korea Society of Computer and Information
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    • v.24 no.7
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    • pp.109-116
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    • 2019
  • In this study, a GIS-based park safety assessment index was developed to enable objective park vulnerability assessment through data-based GIS analysis, a safety assessment was conducted by selecting a target site where various parks are operated and applying the park safety assessment index. In addition, a facility management system was developed for efficient management of the park safety assessment to update the park safety and provide a foothold for indirect PPGIS. In the case of the assessment index of the safety rating of the park, it was possible to conclude that the accurate quantitative performance was given to the calculation of the safety grade of the park based on the fact that the facilities are different depending on the environment and the size of the park. In addition, the marking the safety grade of parks, as well as the function to show the safety facilities of parks, a common living area for citizens, the management system is expected to have an impact on promoting the use of parks. In the future, in functions such as reporting of facility failures and verifying civil information are implemented by applying civic group participation programs and crowd-sourcing technologies, it is believed that all facilities as well as parks managed by the local government can be managed more efficiently.

A Study on the Performance Improvement of the Auto-Tuning PID Controller Using Gradient Method (경사도 기법을 사용한 PID 제어기의 성능 개선에 관한 연구)

  • Ha, Dong-Ho;Jung, Jong-Dae
    • Proceedings of the KIEE Conference
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    • 1999.07b
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    • pp.659-661
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    • 1999
  • In this paper, we proposed a simple neural network-based parameter tuning algorithm, which could find the gradients of a certain performance index in the PID parameter spaces. In this process, we had to know the dynamics between input and output of the plant, and we used the Back Propagation Neural network to identify them. To make the parameter updating fast and smooth, we constructed the performance index as the sum of past N-squared plant errors, and applied a batch mode algorithm to update parameters. We performed several experiments with a DC Motor to show the validity of the proposed algorithm.

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A Digital Forensic Method for File Creation using Journal File of NTFS File System (NTFS 파일 시스템의 저널 파일을 이용한 파일 생성에 대한 디지털 포렌식 방법)

  • Kim, Tae Han;Cho, Gyu Sang
    • Journal of Korea Society of Digital Industry and Information Management
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    • v.6 no.2
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    • pp.107-118
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    • 2010
  • This paper proposes a digital forensic method to a file creation transaction using a journal file($LogFile) on NTFS File System. The journal file contains lots of information which can help recovering the file system when system failure happens, so knowledge of the structure is very helpful for a forensic analysis. The structure of the journal file, however, is not officially opened. We find out the journal file structure with analyzing the structure of log records by using reverse engineering. We show the digital forensic procedure extracting information from the log records of a sample file created on a NTFS volume. The related log records are as follows: bitmap and segment allocation information of MFT entry, index entry allocation information, resident value update information($FILE_NAME, $STANDARD_INFORMATION, and INDEX_ALLOCATION attribute etc.).

Indexing Methods of Splitting XML Documents (XML 문서의 분할 인덱스 기법)

  • Kim, Jong-Myung;Jin, Min
    • Journal of Korea Multimedia Society
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    • v.6 no.3
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    • pp.397-408
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    • 2003
  • Existing indexing mechanisms of XML data using numbering scheme have a drawback of rebuilding the entire index structure when insertion, deletion, and update occurs on the data. We propose a new indexing mechanism based on split blocks to cope with this problem. The XML data are split into blocks, where there exists at most a relationship between two blocks, and numbering scheme is applied to each block. This mechanism reduces the overhead of rebuilding index structures when insertion, deletion, and update occurs on the data. We also propose two algorithms, Parent-Child Block Merge Algorithm and Ancestor-Descendent Algorithm which retrieve the relationship between two entities in the XML hierarchy using this indexing mechanism. We also propose a mechanism in which the identifier of a block has the information of its Parents' block to expedite retrieval process of the ancestor-descendent relationship and also propose two algorithms. Parent-Child Block Merge Algorithm and Ancestor-Descendent Algorithm using this indexing mechanism.

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Reliability Updates of Driven Piles Using Proof Pile Load Test Results (검증용 정재하시험 자료를 이용한 항타강관말뚝의 신뢰성 평가)

  • Park, Jae-Hyun;Kim, Dong-Wook;Kwak, Ki-Seok;Chung, Moon-Kyung;Kim, Jun-Young;Chung, Choong-Ki
    • Proceedings of the Korean Geotechical Society Conference
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    • 2010.03a
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    • pp.324-337
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    • 2010
  • For the development of load and resistance factor design, reliability analysis is required to calibrate resistance factors in the framework of reliability theory. The distribution of measured-to-predicted pile resistance ratio was constructed based on only the results of load tests conducted to failure for the assessment of uncertainty regarding pile resistance and used in the conventional reliability analysis. In other words, successful pile load test (piles resisted twice their design loads without failure) results were discarded, and therefore, were not reflected in the reliability analysis. In this paper, a new systematic method based on Bayesian theory is used to update reliability index of driven steel pile piles by adding more pile load test results, even not conducted to failure, into the prior distribution of pile resistance ratio. Fifty seven static pile load tests performed to failure in Korea were compiled for the construction of prior distribution of pile resistance ratio. Reliability analyses were performed using the updated distribution of pile resistance ratio and the total load distribution using First-order Reliability Method (FORM). The challenge of this study is that the distribution updates of pile resistance ratio are possible using the load test results even not conducted to failure, and that Bayesian update are most effective when limited data are available for reliability analysis or resistance factors calibration.

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Inverted Indexes for XML Updates and Full-Text Retrievals in Relational Model (관계형 모델에서 XML 변경과 전문 검색을 지원하기 위한 역 인덱스 구축 기법)

  • Cheon, Yun-Woo;Hong, Dong-Kweon
    • The KIPS Transactions:PartD
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    • v.11D no.3
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    • pp.509-518
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    • 2004
  • Recently there has been some efforts to add XML full-text retrievals and XML updates into new standardization of XML queries. XML full-text retrievals plays an important role in XML query languages. of like tables in relational model an XML document has complex and unstructured natures. We believe that when we try to get some information from unstructured XML documents a full-text retrieval query is much more convenient approach than a regular structured query XML update is another core function that an XML query have to have. In this paper we propose an inverted index to support XML updates and XML full-text queries in relational environment. Performance comparisons exhibit that our approach maintains a comparable size of inverted indexes and it supports many full-text retrieval functions very well. It also shows very stable retrieval performance especially for large size of XML documents. Foremost our approach handles XML updates efficiently by removing cascading effects.