• 정보기술과데이타베이스저널
• /
• 제6권2호
• /
• pp.71-86
• /
• 1999

The performance of relational database is measured by the number of disk accesses necessary to transfer data from disk to main memory. The paper proposes to vertically partition relations into fragments and to allow attribute replication to reduce the number of disk accesses. To reduce the computational time, heuristic search method using genetic algorithm is used. Genetic algorithm used employs a rank-based-sharing fitness function and elitism. Desirable parameters of genetic algorithm are obtained through experiments and used to find the solutions. Solutions of attribute replication and attribute non-replication problems are compared. Optimal solutions obtained by branch and bound method and by heuristic solutions(genetic algorithm) are also discussed. The solution method proposed is able to solve large-sized problems within acceptable time limit and shows solutions near the optimal value.

• 인터넷정보학회논문지
• /
• 제19권5호
• /
• pp.107-113
• /
• 2018

Object-oriented databases (OODBs) canbe used for many non-traditional database application areas such as computer-aided design, etc. Usually those application areas require advanced modeling power for expressing complicated relationships among data sets. OODBs have more distinguished features than the traditional relational database systems. One of the distinguished characteristics of OODBs is class hierarchy (also called inheritance hierarchy). A class hierarchy in an OODB means that a class can hand down the definitions of the class to the subclass of the class. In other words, a class is allowed to inherit the definitions of the class from the superclass. In this paper, we present performance evaluation metrics for class hierarchy in OODBs from a concurrency control perspective. The proposed performance metrics are developed to determine which concurrency control scheme in OODBs can be used for a given class hierarchy. In this study, in order to develop performance metrics, we use class hierarchy structure (both of single inheritance and multiple inheritance), and data access frequency for each class. The proposed performance metrics will be also used to compare performance evaluation for various concurrency control techniques.

• 한국CDE학회지
• /
• 제3권3호
• /
• pp.36-45
• /
• 1997

This paper presents the research on the development of Generic modeling system as a 3D CAD customizing system for the elevator design. This system enables to create a generic model which gives birth to many models. The generic model is expressed as a non-scale model or a standard model in this paper. Using the parametric design techniques, all their relationships are explicitly represented in the tables, not represented in implicit embedded coding. Owing to this method, designers can easily extend the generic model to contain more model families. All parametric relations are stored in relational database. A designer can retrieve various models from a generic model automatically, by using some key input values.

• 산업경영시스템학회지
• /
• 제21권46호
• /
• pp.33-49
• /
• 1998

In order to improve the performance of relational databases, one has to reduce the number of disk accesses necessary to transfer data from disk to main memory. The paper proposes to reduce the number of disk I/O accesses by vertically partitioning relation into fragments and allowing attribute replication to fragments if necessary. When zero-one integer programming model is solved by the branch-and-bound method, it requires much computing time to solve a large sized problem. Therefore, heuristic solutions using genetic algorithm(GA) are presented. GA in this paper adapts a few ideas which are different from traditional genetic algorithms, for examples, a rank-based sharing fitness function, elitism and so on. In order to improve performance of GA, a set of optimal parameter levels is determined by the experiment and makes use of it. As relations are vertically partitioned allowing attribute replications and saved in disk, an attribute replicating vertical partition method by GA can attain less access cost than non-attribute-replication one and require less computing time than the branch-and-bound method in large-sized problems. Also, it can acquire a good solution similar to the optimum solution in small-sized problem.

• 한국융합학회논문지
• /
• 제12권7호
• /
• pp.45-51
• /
• 2021

급속한 비대면 환경과 모바일 우선 전략에 따라 해마다 많은 정형/비정형 데이터의 폭발적인 증가와 생성은 모든 분야에서 빅데이터를 활용한 새로운 의사 결정과 서비스를 요구하고 있다. 그러나 매년 급속히 증가하는 빅데이터를 활용하여 실무 환경에서 적용 가능한 표준 플랫폼으로 빅데이터를 수집하여 적재한 후, 정재한 빅데이터를 관계형 데이터베이스에 저장하고 처리하는 하둡 에코시스템 활용의 참조 사례들은 거의 없었다. 따라서 본 연구에서는 스프링 프레임워크 환경에서 3대의 가상 머신 서버를 통하여 하둡 2.0을 기반으로 쇼셜 네트워크 서비스에서 키워드로 검색한 비정형 데이터를 수집한 후, 수집된 비정형 데이터를 하둡 분산 파일 시스템과 HBase에 적재하고, 적재된 비정형 데이터를 기반으로 형태소 분석기를 이용하여 정형화된 빅데이터를 관계형 데이터베이스에 저장할 수 있게 설계하고 구현하였다. 향후에는 데이터 심화 분석을 위한 하이브나 머하웃을 이용하여 머신 러닝을 이용한 클러스터링과 분류 및 분석 작업 연구가 지속되어야 할 것이다.

• 정보보호학회논문지
• /
• 제30권3호
• /
• pp.455-464
• /
• 2020

데이터 활용의 다양성이 높아짐에 따라 비관계형 데이터베이스 사용이 증가했으며, 이에 대한 NoSQL 삽입 공격 또한 증가했다. 전통적으로 NoSQL 삽입 공격을 탐지하기 위해 규칙 기반 탐지 방법론이 제안돼왔으나, 이 방식은 규칙의 범위를 벗어나 발생하는 삽입 공격에의 대응이 어렵다는 한계점이 있다. 이에 본 논문에서는 CNN 알고리즘을 이용해 특징을 추출하고, RNN 알고리즘을 활용해 NoSQL 삽입 공격을 탐지하는 기법을 제시한다. 또한, 실험을 통하여 본 논문에서 제시한 모델이 기존의 지도학습을 이용한 가장 우수한 모델보다 정확도는 10%, 정밀도는 4%, 재현율은 14%, F2-score는 0.082만큼 더 높은 비율로 NoSQL 삽입 공격을 탐지함을 보인다.

• 한국국방경영분석학회지
• /
• 제22권1호
• /
• pp.81-96
• /
• 1996

In a relational database environment, partitioning of data is directly concerned with the amount of data that needs to be required in a query or transaction. In this paper, we consider non-overlapping, vertical partitioning. Vertical partitioning algorithm in this paper is composed of two phases. In phase 1, we cluster the attributes with zero-one integer program that maximize affinity among attributes. The result of phase 1 is called 'Initial Fragments'. In phase 2, we modify Initial Fragments that is not directly considered by cost factors, making use of a transaction-based partitioning method. A transaction-based partitioning method is partitioning attributes according to a set of transactions. In this phase we select logical accesses which needs to be required in a transaction as comparison criteria. In phase 2, proposed algorithm consider only small number of modification of Initial Fragments in phase 1. This algorithm is so insensible to number of transactions and of attributes that it can applied to relatively large problems easily.

• Genomics & Informatics
• /
• 제4권1호
• /
• pp.45-47
• /
• 2006

D2GSNP is a web-based server for the selection of single nucleotide polymorph isms (SNPs) within genes related to human diseases. The D2GSNP is based on a relational database created by downloading and parsing OMIM, GAD, and dbSNP, and merging it with positional information of UCSC Golden Path. Totally our server provides 5,142 and 1,932 non-redundant disease genes from OMIM and GAD, respectively. With the D2GSNP web interface, users can select SNPs within genes responding to certain diseases and get their flanking sequences for further genotyping experiments such as association studies.

• 한국측량학회지
• /
• 제11권1호
• /
• pp.67-75
• /
• 1993

도시팽창 및 현대화에 따른 도시기반시설의 확충은 효율적인 도시정보관리를 위한 새로운 기법을 필요로 하게 되었으며, 최근 각종 도시기반시설 정보처리에 이용되는 토지정보체계는 좋은 예이다. 도시기반 시설정보체계 중 하수정보체계 또한 업무의 효율화, 고도화를 위해 토지정보체계의 이용이 필요하며, 비 전문가의 용이한 접근을 위해서는 전문가 기법의 이용이 또한 필요하다. 본 연구는 관계형 데이타베이스의 분석 및 조회 능력과 벡터를 기본으로 하는 토지정보체계의 Chain Topology Generator 기능, 하수시설 용량산출에 관한 전문가 지식을 통합하여 사용자 편의를 도모하고, 사전정보의 제공으로 예측계획을 가능하게 하며, 하수량 분석 및 예측을 자동화한 도시 하수용량 분석 시스템을 개발하여 서울시의 사례지역에 적용하였다.

• 한국의류학회지
• /
• 제37권3호
• /
• pp.386-398
• /
• 2013

This study analyzes the effect of clothing involvement using meta-analysis. Metal-analysis (the analysis of analyses) is widely used in various academic areas to integrate individual empirical studies and generalize the knowledge of a specific research field. Previous studies regarding clothing involvement published since 1990 were researched from the KISS database using clothing involvement and fashion involvement as a keyword; subsequently, 127 articles were identified. Studies that had insufficient statistics or included clothing involvement as a moderating (or intervening variable) were eliminated; subsequently, 36 articles provided a total of 75 data sets that were used for the final analysis. Dependent variables were grouped into 10 categories to compare the differences between high and low involvement groups. The effect size of clothing involvement was large in non-personal information source; however, it was small in utility, brand royalty and quality. In the 7 categories of relational studies that showed homogeneity, the relation size regarding conformity was smaller than the personal information source.