• Journal of KIISE:Databases
• /
• v.29 no.5
• /
• pp.404-415
• /
• 2002

In this paper, we address the issue of ensuring consistency of multiple data items requested in a certain order by read-only transactions in a wireless data broadcast environment. To handle the inherent property in a data broadcast environment that data can only be accessed strictly sequential by users, we explore a predeclaration-based query optimization and devise two practical transaction processing methods in the context of local caching. We also evaluate the performance of the proposed methods by an analytical study Evaluation results show that the predeclaration technique we introduce reduces response time significantly and adapts to dynamic changes in workload.

• Journal of KIISE:Computing Practices and Letters
• /
• v.5 no.6
• /
• pp.663-673
• /
• 1999

WWW에 있어서 데이타베이스 통로는 필수적이다. 데이타베이스를 이용한 대부분의 웹 서비스는 CGI를 통해서 이루어지고 있는데 본 논문에서는 CGI가 갖는 문제점을 근본적으로 해결하기 위한 프레임웍으로서 JAQS(JAva Query Stub)를 제안하고 있다. JAQS를 통하여 이루어지는 서비스는 HTTP의 비연결성(connectionless) 및 무상태성(stateless)을 극복함으로써 상태 및 트랜잭션 관리를 지원할 수 있음은 물론 자바언어로 구현되어 플랫폼 독립적인 구조와 다중쓰레드를 최대한 활용하고 있다. 또한 JAQS와 함께 제안하고 있는 JAQS 관리자를 이용하면 데이타베이스가 분산되어 있는 환경에서도 효율적으로 동작할 수 있는 구조로 이루어져있다.Abstract Database gateway is absolutely vital to web-based services. Most web-based services with DBMS are implemented using CGI(Common Gateway Interface). This paper proposes a framework, dubbed JAQS(JAva Query Stub), as a solution for problems of CGI. JAQS not only supports state/transaction management by overcoming the connectionless and stateless nature of HTTP, but also effectively guarantees platform/DBMS-independence and multi-threading abilities because JAQS is implemented using Java. Also, using the JAQS Manager additionally proposed in this paper, JAQS can operate efficiently even in distributed database environments.

• Proceedings of the KIEE Conference
• /
• 1988.07a
• /
• pp.640-643
• /
• 1988

This paper is concerned with distributed INGRES database system. The main motivation is to provide dynamic reconfiguration and global database consistency. Dynamic reconfiguration will provide proper initial environment to newly generated system. By use of transaction characteristic, database can be maintained in consistent state.

• The KIPS Transactions:PartD
• /
• v.8D no.5
• /
• pp.605-612
• /
• 2001

In order to solve the overload of academic affairs management system, we propose a method builds a distributed Replication server and uses this server with the present centralized system. Normal query transactions which are not required for data modification are composed of almost all DML sentences. So we construct the distributed replication servers according to the data characteristics and make them perform the query transaction without modification. In this way, we can simultaneously distribute users and data, and cut down processing time for every transaction. Also Replication server has the advantages of implemental efficiency and economical because it uses resources of present centralized system without and additional configurations. Usually, to distribute the overload of server, they can use way, Client-side overload distribution that user program get present overload status then can choose a less overloaded server, and the other way, Server-side overload distribution that make use of Application Layer Scheduling Technique and IP Layer Scheduling Technique. Our Replication server can reduce the overload of centralized system by eliminating or complementing those defects of overload distribution, referred to in the forehead.

• The KIPS Transactions:PartD
• /
• v.13D no.3 s.106
• /
• pp.293-298
• /
• 2006

Many data are stored in database. For getting any information from many data, we use the query sentences. These information is basic and simple. Data mining method is various. In this paper, we manage clustering and association rules. We present a method for finding the better association rules, and we solve a problem of the existing association rules. We propose and apply a new clustering method to fit for association rules. It is not clustering of the existing distance basis or category basis. If we find association rules of each clusters, we can get not only existing rules found in all transaction but also rules that will be characteristics of clusters. Through this study, we can expect that we will reduce the number of many transaction access in large databases and find association of small group.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.11 no.9
• /
• pp.1771-1780
• /
• 2007

The necessity of Information integration has emphasized by advancement of internet and change of enterprise environment. In enterprises, it usually integrates the multi-database constructing by M&A. For this integration of information it must guarantee interpretation and integration which is stabilized with solving heterogeneous characteristic problem. In this paper, we propose the method that change the global XML query to local XML query for interpretation. It is based on XMDR(eXtended Meta-Data Registry) which expresses the connection between the standard and the local for solve the interoperability problem in heterogeneous environment. Thus, we propose the legacy model that can search and modify by one Query with creating global XML Query by XMDR. and for his, we use the 2PC technique which is the distributed transaction control technique of existing.

• Journal of the Korean Society for information Management
• /
• v.32 no.4
• /
• pp.289-305
• /
• 2015

This study aims to investigate information seeking behavior of Popshoes users. Transaction logs of Popshoes, a major Korean shopping search engine, were analyzed. These transaction logs were collected over 3 months period, from January 1 to March 31, 2015. The results of this study show that Popshoes users behave in a simple and passive way. In the total sessions, more users chose to browse a directory than typing and submitting a query. However, queries played a more crucial role in important decision makings such as search results clicks and product purchases than directory browsing. The results of this study can be implemented to the effective development of shopping search engines.

• ETRI Journal
• /
• v.11 no.2
• /
• pp.120-136
• /
• 1989

최근의 데이터 베이스 응용분야에 있어서 시간에 따른 정보의 변화를 유지관리할 필요성이 대두되고 대용량의 기억장치 가격의 급속한 감소와 함께 이의 이용 기술이 향상되면서 시간주기에 따라 실세계의 상태에 대한 변경과정을 표현하는 시간 즉, 데이터의 변경이력을 지원하는 데이터베이스(Terporal Database)에 관심이 집중되고 있으며, 이러한 요구를 만족시키기 위한 여러 방법들이 연구되고 있다. 일반적으로 시간 지원 데이터베이스 모델은 지원되는 시간의 형태에 따라 Static, Static Rollback, Historical, Temporal, Revision 데이터베이스 모델로 나뉘어진다. 본 논문에서는 시간 및 변경이력을 지원하기 위한 데이터베이스 모델과 이를 위한 데이터베이스 시스템의 주요 설계 Issue들에 관하여 조사분석한 다음, Static Rollback 데이터베이스 모델을 기본으로 하는 "$SR^2DBS$: 시간 지원 데이터베이스 시스팀"의 설계 및 구현에 관하여 기술하였다. $SR^2DBS$은 기존의 관계형 데이터 베이스 시스팀"의 모델을 시간 애트리뷰트를 추가시킴으로서 데이터 베이스의 변경이력관리를 가능케 한 Direct Manipulation Database Processing System으로 데이터베이스의 현상태 뿐만 아니라 시간에 따른 변경이력에 대해서 Screenoriented Relation Browsing & Editing 기능을 제공하며, 다음과 같은 특징을 갖는다. - Screen oriented Processing - Directi-Manipulation of Objects - Object & Revision History of Interest Visibility - Rapid Reversible Actions - Transaction Time & Revision Number Supporting - Roll-back Query Supporting - Han-gul Data Supporting - Two level Storage Structure(Current Version & History Versions)

• The KIPS Transactions:PartC
• /
• v.9C no.1
• /
• pp.115-122
• /
• 2002

This paper presents a new web cluster scheme based on dispatcher which does not depend on operating system for server and can examine server's status interactively. Two principal functions are proposed for new web cluster technique. The one is self-controlled load distribution and the other is transaction fail-safe. Self-controlled load distribution function checks response time and status of servers periodically, then it decides where the traffic goes to guarantee rapid response for every query. Transaction fail-safe function can recover lost queries including broken transaction immediately from server errors. Proposed new web cluster scheme is implemented by C language on Unix operating system and compared with legacy web cluster products. On the comparison with broadcast based web cluster, proposed new web cluster results higher performance as more traffic comes. And on the comparison with a round-robin DNS based web cluster, it results similar performance at the case of traffic processing. But when the situation of one server crashed, proposed web cluster processed traffics more reliably without lost queries. So, new web cluster scheme Proposed on this dissertation can give alternative plan about highly increasing traffics and server load due to heavy traffics to build more reliable and utilized services.

• The Journal of Information Technology and Database
• /
• v.3 no.1
• /
• 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.