• Title/Summary/Keyword: Data base

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The Fault Diagnosis Method of Diesel Engines Using a Statistical Analysis Method (통계적분석기법을 이용한 디젤기관의 고장진단 방법에 관한 연구)

  • Kim, Young-Il;Oh, Hyun-Gyeong;Cheon, Hang-Chun;Yu, Yung-Ho
    • Proceedings of the Korean Society of Marine Engineers Conference
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    • 2005.06a
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    • pp.281-286
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    • 2005
  • Almost ship monitoring systems are event driven alarm system which warn only when the measurement value is over or under set point. These kinds of system cannot warn while signal is growing to abnormal state until the signal is over or under the set point and cannot play a role for preventive maintenance system. This paper proposes fault diagnosis method which is able to diagnose and forecast the fault from present operating condition by analyzing monitored signals with present ship monitoring system without additional sensors. By analyzing this data having high correlation coefficient(CC), correlation level of interactive data can be understood. Knowledge base of abnormal detection can be built by referring level of CC(Fault Detection CC, FDCC) to detect abnormal data among monitored data from monitoring system and knowledge base of diagnosis built by referring CC among interactive data for related machine each other to diagnose fault part.

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Financial Performance Evaluation using Self-Organizing Maps: The Case of Korean Listed Companies (자기조직화 지도를 이용한 한국 기업의 재무성과 평가)

  • 민재형;이영찬
    • Journal of the Korean Operations Research and Management Science Society
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    • v.26 no.3
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    • pp.1-20
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    • 2001
  • The amount of financial information in sophisticated large data bases is huge and makes interfirm performance comparisons very difficult or at least very time consuming. The purpose of this paper is to investigate whether neural networks in the form of self-organizing maps (SOM) can be successfully employed to manage the complexity for competitive financial benchmarking. SOM is known to be very effective to visualize results by projecting multi-dimensional financial data into two-dimensional output space. Using the SOM, we overcome the problems of finding an appropriate underlying distribution and the functional form of data when structuring and analyzing a large data base, and show an efficient procedure of competitive financial benchmarking through clustering firms on two-dimensional visual space according to their respective financial competitiveness. For the empirical purpose, we analyze the data base of annual reports of 100 Korean listed companies over the years 1998, 1999, and 2000.

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Ontology-lexicon-based question answering over linked data

  • Jabalameli, Mehdi;Nematbakhsh, Mohammadali;Zaeri, Ahmad
    • ETRI Journal
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    • v.42 no.2
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    • pp.239-246
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    • 2020
  • Recently, Linked Open Data has become a large set of knowledge bases. Therefore, the need to query Linked Data using question answering (QA) techniques has attracted the attention of many researchers. A QA system translates natural language questions into structured queries, such as SPARQL queries, to be executed over Linked Data. The two main challenges in such systems are lexical and semantic gaps. A lexical gap refers to the difference between the vocabularies used in an input question and those used in the knowledge base. A semantic gap refers to the difference between expressed information needs and the representation of the knowledge base. In this paper, we present a novel method using an ontology lexicon and dependency parse trees to overcome lexical and semantic gaps. The proposed technique is evaluated on the QALD-5 benchmark and exhibits promising results.

Research on Geodetic Data Standard System

  • Zhiping, Lu;Xiguang, Zhang
    • Proceedings of the KSRS Conference
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    • 2003.11a
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    • pp.53-56
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    • 2003
  • Aiming at importance of geodetic data standards in process of digitized geodetic production, application and service, this paper discusses the content framework of geodetic technical base standard, information system standard and data service standard. Hierarchy relation and category relation of geodetic data standard system are established in this paper.

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Antibacterial and Antifungal Studies on Some Schiff Base Complexes of Zinc(II)

  • Joseyphus, R. Selwin;Nair, M. Sivasankaran
    • Mycobiology
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    • v.36 no.2
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    • pp.93-98
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    • 2008
  • Two Schiff base ligands $L_1\;and\;L_2$ were obtained by the condensation of glycylglycine respectively with imidazole-2-carboxaldehyde and indole-3-carboxaldehyde and their complexes with Zn(II) were prepared and characterized by microanalytical, conductivity measurement, IR, UV-Vis., XRD and SEM. The molar conductance measurement indicates that the Zn(II) complexes are 1:1 electrolytes. The IR data demonstrate the tetradentate binding of $L_1$ and tridentate binding of $L_2$. The XRD data show that Zn(II) complexes with $L_1\;and\;L_2$ have the crystallite sizes of 53 and 61 nm respectively. The surface morphology of the complexes was studied using SEM. The in vitro biological screening effects of the investigated compounds were tested against the bacterial species Staphylococcus aureus, Escherichia coli, Klebsiella pneumaniae, Proteus vulgaris and Pseudomonas aeruginosa and fungal species Aspergillus niger, Rhizopus stolonifer, Aspergillus flavus, Rhizoctonia bataicola and Candida albicans by the disc diffusion method. A comparative study of inhibition values of the Schiff base ligands and their complexes indicates that the complexes exhibit higher antimicrobial activity than the free ligands. Zinc ions are proven to be essential for the growth-inhibitor effect. The extent of inhibition appeared to be strongly dependent on the initial cell density and on the growth medium.

Computer-Aided Alloy Design of Insert Metal for Transient Liquid Phase Bonding of High Aluminum Ni-base Superalloys

  • Nishimotd, Kazutoshi;Saida, Kazuyoshi
    • Proceedings of the KWS Conference
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    • 2002.10a
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    • pp.803-808
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    • 2002
  • A computer-aided alloy-designing technique to develop the insert metal for transient liquid phase (TLP) bonding was applied to high aluminum Ni-base superalloys. The main procedure of a mathematical programming method was to obtain the optimal chemical composition through rationally compromising the plural objective performances of insert metal by a grid-search which involved data estimation from the limited experimental data using interpolation method. The objective function Z which was introduced as an index of bonding performance of insert metal involved the melting point, hardness (strength), formability of brittle phases and void ratio (bonding defects) in bond layer as the evaluating factors. The contour maps of objective function Z were also obtained applying the interpolation method. The compositions of Ni-3.0%Cr-4.0%B-0.5%Ce (for ${\gamma}$/${\gamma}$/${\beta}$ type alloy) and Ni3.5%Cr-3.5%B-3%Ti (for ${\gamma}$/${\gamma}$ type alloy) which optimized the objective function were determined as insert metal. SEM observations revealed that the microstructure in bond layers using the newly developed insert metals indicated quite sound morphologies without forming microconstituents and voids. The creep rupture properties of both joints were much improved compared to a commercial insert metal of MBF-80 (Ni-15.5%Cr-3.7%B), and were fairly comparable to those of base metals.

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