• 제목/요약/키워드: Relational performance

검색결과 355건 처리시간 0.027초

관계형 데이터베이스에서 비정규화를 사용한 데이터베이스 설계 (A database design using denormalization in relational database)

  • 장영관;강맹규
    • 한국경영과학회:학술대회논문집
    • /
    • 대한산업공학회/한국경영과학회 1996년도 춘계공동학술대회논문집; 공군사관학교, 청주; 26-27 Apr. 1996
    • /
    • pp.172-178
    • /
    • 1996
  • Databases are critical to business information systems, and RDBMS is most widely usded for the database system. Normalization has been designed to control various anomalies(insert, update, and delete anomalies). However, normalized databese design does not account for the tradeoffs necessary for the performance. In this research, we develop a model for database desin by denormalization of duplicating attributes in order to reduce frequent join processes. In this model, we consider insert, update, and delete costs. The anomalies are treated by additional disk I/O which is necessary for each insert and update transaction. We propose a branch and bound method for this model, and show considerable cost reduction.

  • PDF

지식 전파에 있어 네트워크 구조와 지식 탐색의 상호작용 (Interaction Effect of Network Structure and Knowledge Search on Knowledge Diffusion)

  • 박철순
    • 경영과학
    • /
    • 제32권4호
    • /
    • pp.81-96
    • /
    • 2015
  • This paper models knowledge diffusion on an inter-organizational network. Based on literatures related to knowledge diffusion, the model considers critical factors that affect diffusion behavior including nodal property, relational property, and environmental property. We examine the relationships among network structure, knowledge search, and diffusion performance. Through a massive simulation runs based on the agent-based model, we find that the average path length of a network decreases a firm's cumulative knowledge stock, whereas the clustering coefficient of a firm has no significant relationship with the firm's knowledge. We also find that there is an interaction effect of network structure and the range of knowledge search on knowledge diffusion. Specifically, in a network of a larger average path length (APL) the marginal effect of search conduct is significantly greater than in that of a smaller APL.

회귀분석을 통한 역진자 시스템의 마찰력 측정에 관한 연구 (A Study on Friction Measurement of an Inverted Pendulum System using the Regression Analysis)

  • 박경윤;박덕기;좌동경;홍석교
    • 대한전기학회:학술대회논문집
    • /
    • 대한전기학회 2006년도 제37회 하계학술대회 논문집 D
    • /
    • pp.1775-1776
    • /
    • 2006
  • This paper deals with the problem of friction measurement of an inverted pendulum system using the regression analysis and proposes a solution. The approach taken in this study is getting the friction from a regression relational expression between the motor voltage and the cart velocity of an inverted pendulum system. The result to compensate LQR (linear Quadratic Regulator) controller with the friction which is measured in system, improved the performance of the system. Above all, the study has found that the proposed compensation of the friction reduces the oscillation of the cart position. In conclusion, the proposed method is useful when parameters in the given system model are not known.

  • PDF

The Impacts of Institutional Environment, Social Capital and Strategic Importance on Knowledge Sharing and Performance

  • Kwon, Soo-Ra
    • Journal of Information Technology Applications and Management
    • /
    • 제15권3호
    • /
    • pp.275-286
    • /
    • 2008
  • Employing a sample of 126 suppliers in Korean electronic industry, this research examined the effects of institutional environment, social capital and strategic importance in manufacturer-supplier relationships on knowledge sharing. Building on the relational view and knowledge-based theories, this study proposed that these factors facilitate knowledge sharing in manufacturer-supplier relationships and that knowledge mediates satisfaction between manufacturer-supplier relationships for competitive advantage. Results indicate that institutional environment, social capital and strategic importance in manufacturer-supplier relationships are indeed associated with greater knowledge sharing. Inter-firm satisfaction is, in turn, positively associated with knowledge sharing for competitive advantage through technical support, financial support, competence increasing. Further, results provide evidence that knowledge sharing plays a mediating role between institutional environment, social capital, strategic importance and inter-firm satisfaction.

  • PDF

엔진 냉각 시스템의 이론적 시뮬레이션 프로그램 개발 (Development of simulation program for automotive engine cooling system)

  • 이승희;신창훈;박원규;양장식;김은필;서정식
    • 대한기계학회:학술대회논문집
    • /
    • 대한기계학회 2000년도 추계학술대회논문집B
    • /
    • pp.341-346
    • /
    • 2000
  • A numerical simulation has been carried out for the engine cooling system. It is the important element to analysis of heat transfer process in cooling system for an automotive engine. Thus, the purpose of this simulator is to present useful information at the early stages of the design of the cooling system by enabling the development engineer to predict performance trends. This program has useful window interface for analysis of the cooling system and it is convenient for user to control data with relational database. The system was simulated and compared with experimental data. As a result, the inlet, outlet temperature of the radiator by the simulator agrees well with it. It is concluded that this simulation program is available in developing the cooling system for a new car.

  • PDF

관계형 데이터베이스에서 저장용량에 제약이 없는 경우 비 정규화를 고려한 데이터베이스 설계 (A Database Design without Storage Constraint Considering Denormalization in Relational Database)

  • 장영관;강맹규
    • 산업경영시스템학회지
    • /
    • 제19권37호
    • /
    • pp.251-261
    • /
    • 1996
  • Databases are critical to business information systems and RDBMS is most widely used for the database system. Normalization was designed to control various anomalies(insert, update, and delete anomalies). However normalized database design does not account for the tradeoffs necessary for the performance reason. In this research, we model a database design problem without storage constraint. Given a normalized database design, in this model, we do the denormalization of duplicating columns in order in reduce frequent join processes. In this paper, we consider insert, update, delete, and storage cost, and the anomalies are treated by additional disk I/O cost necessary for each insert, update transaction. We propose a branch and bound method, and show considerable cost reduction.

  • PDF

관계형 데이터베이스에서 비정규화를 고려한 최적 데이터베이스 설계 (An Optimal Database Design Considering Denormalization in Relational Database)

  • 장영관;강맹규
    • 정보기술과데이타베이스저널
    • /
    • 제3권1호
    • /
    • pp.3-24
    • /
    • 1996
  • Databases are critical to business information systems, and RDBMS is most widely used for the database system. Normalization has been designed to control various anomalies(insert, update, and delete anomalies). However, normalized database design does not account for the tradeoffs necessary for the performance. In this research, we develop a model for database design by denormalization of duplicating attributes in order to reduce frequent join processes. In this mood, we consider insert, update, delete, and query costs. The anomaly and data inconsistency are removed by additional disk I/O which is necessary for each update and insert transaction. We propose a branch and bound method for this model, and show considerable cost reduction.

  • PDF

New Compression Scheme for Multispectral Images

  • Park, Jeong-Ho;Yun, Young-Bo;Park, Jong-Hyun
    • 대한원격탐사학회:학술대회논문집
    • /
    • 대한원격탐사학회 1998년도 Proceedings of International Symposium on Remote Sensing
    • /
    • pp.565-568
    • /
    • 1998
  • In this paper, we propose a new method for multispectral image compression that is based on highly correlated relational properly taken from a spatial image and its wavelet transform. The highly active regions, such as edges or contour, in the spatial domain are appeared as significant coefficients in the wavelet transform domain; and the low active regions like background as insignificant. These characteristics play an important role in designing the system. The simulation results have shown us that the proposed method has better performance in terms of the reconstructed image quality and the transmitted bit rakes. Practically, our system can be successfully applied to the application areas that require of progressive transmission. For some multispectral images with relatively low activity, we have obtained the more good results.

  • PDF

효율적인 온톨로지 추론 질의를 지원하는 OWL 저장 모델 (OWL Storage Model to Support Efficient Ontology Reasoning Query)

  • 김연희;이애정
    • 디지털산업정보학회논문지
    • /
    • 제7권3호
    • /
    • pp.25-35
    • /
    • 2011
  • In the Semantic Web, storage models are required to efficiently store and retrieve metadata and ontology represented using OWL that can provide expressive power and reasoning support. In this paper, we propose an OWL storage model that can store and retrieve many restrictions and semantic relations defined on ontology with metadata. In addition, we propose some methods and rules to improve query processing efficiency of the proposed storage model. The proposed storage model can store and process large amounts of ontology and metadata because it consists of tables based on the relational database. And the proposed model can quickly provide more accurate results to users because of performing two different types of ontology reasoning and using the prime number labeling scheme to easily identify hierarchy relationships between classes or properties. The comparative evaluation results show that our storage model provides better performance than the existing storage model.

퍼지관계곱을 이용한 정보검색시스템의 성능 개선 (Performance Improvement of Information Retrieval System by means of Fuzzy Relational Product)

  • 김창민;김용기
    • 한국지능시스템학회논문지
    • /
    • 제10권3호
    • /
    • pp.242-251
    • /
    • 2000
  • 퍼지관계 개념을 응용한 BK-퍼지정보검색기법은 형태론에 입각하는 기존의 정보검색기법과는 달리 문서와 용어의 상대적 의미에 근거한 정보검색 기법이다. 그러나 BK-퍼지정보검색기법은 높은 시간복잡도(time complexity)의 검색 연산을 내재하고 있어 실제 대용량의 정보 검색은 사실상 불가능하다. 본 논문에서는 BK-퍼지검색정보모델의 시간복잡도를 낮추기 위해, 축소용어집합(reduced term set)을 이용한 개선된 BK-퍼지정보검색모델(A-FIRM)을 제안한다. 개선된 BK-FIRM은 시스템 처리시간과 신뢰도 간 상층점(trade-off)을 제공한다. 축소용어집합은 용어집합의 부분집합으로서 검색결과의 신뢰도와 밀접한 관계를 가진다. 동일한 크기의 축소용어집합이 주어질 때, 보다 적절한 용어들로 구성된 축소용어집합이 보다 나은 검색 신뢰도를 이끈다. 따라서 보다 적절한 축소용어집합 구성을 위한 축소용어집합 추출방법이 요구된다. 본 논문에서는 축소용어집합 추출방법을 크게 무작위 추출, 규칙에 의한 추출, 인간에 의한 직관적 추출 방법으로 구분하고 검색결과의 신뢰도 변화 형태를 분석한다.

  • PDF