• Title/Summary/Keyword: Distributed Database Systems

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A Study on the File Allocation in Distributed Computer Systems (분산 컴퓨터 시스템에서 파일 할당에 관한 연구)

  • 홍진표;임재택
    • Journal of the Korean Institute of Telematics and Electronics
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    • v.27 no.4
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    • pp.571-579
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    • 1990
  • A dynamic relocation algorithm for non-deterministic process graph in distributed computer systems is proposed. A method is represented for determining the optimal policy for processing a process tree. A general database query request is modelled by a process tree which represent a set of subprocesses together with their precedence relationship. The process allocation model is based on operating cost which is a function fo selection of site for processing operation, data reduction function and file size. By using expected values of parameters for non-deterministic process tree, the process graph and optimal policy that yield minimum operating cost are determined. As process is relocated according to threshold value and new information of parameters after the execution of low level process for non-deterministic process graph, the assigned state that approximate to optiaml solution is obtained. The proposed algorihtm is heuristic By performing algorithm for sample problems, it is shown that the proposed algorithm is good in obtaining optimal solution.

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The Design of Open Architectured Manufacturing System based on RT CORBA

  • Yi, Gi-Woong;Kim, Hong-Rok;Suh, Il-Hong;Park, Myong-Kwan
    • 제어로봇시스템학회:학술대회논문집
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    • 2001.10a
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    • pp.52.4-52
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    • 2001
  • In this paper we propose a framework of an open architectured manufacturing system base on CORBA middleware. The manufacturing system consists of four configurable software modules 9mchine control module, database module, monitoring module, and operation module). Each module is distributed through the network and integrated with CORBA middleware technology. CORBA Characteristics including independence from programming languages, computing platforms and networking protocols makes us to easily develop new applications and to effectively integrate new module into existing distributed systems. The CORBA program used in this study is The ACE ORB (TAO) developed by the laboratory in Washington University.

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Contribution to Improve Database Classification Algorithms for Multi-Database Mining

  • Miloudi, Salim;Rahal, Sid Ahmed;Khiat, Salim
    • Journal of Information Processing Systems
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    • v.14 no.3
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    • pp.709-726
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    • 2018
  • Database classification is an important preprocessing step for the multi-database mining (MDM). In fact, when a multi-branch company needs to explore its distributed data for decision making, it is imperative to classify these multiple databases into similar clusters before analyzing the data. To search for the best classification of a set of n databases, existing algorithms generate from 1 to ($n^2-n$)/2 candidate classifications. Although each candidate classification is included in the next one (i.e., clusters in the current classification are subsets of clusters in the next classification), existing algorithms generate each classification independently, that is, without taking into account the use of clusters from the previous classification. Consequently, existing algorithms are time consuming, especially when the number of candidate classifications increases. To overcome the latter problem, we propose in this paper an efficient approach that represents the problem of classifying the multiple databases as a problem of identifying the connected components of an undirected weighted graph. Theoretical analysis and experiments on public databases confirm the efficiency of our algorithm against existing works and that it overcomes the problem of increase in the execution time.

The Implementation of Spatial Database Transaction Model (FTMSD) supporting Mobile Host (이동 호스트를 지원하는 공간 데이터베이스 트랜잭션 모델(FTMSD)의 구현)

  • Lee, Young-Geol;Kim, Sung-Hee;Bae, Young-Ho;Jeong, Mi-Young;Jung, Hyun-Meen
    • Journal of the Korea Society of Computer and Information
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    • v.11 no.5 s.43
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    • pp.175-181
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    • 2006
  • AMobile-supported spatial database systems have been introduced with development of mobile computing technology, they offer an advantage that we can access the data wherever we are. However, the studies on database system in traditional distributed environments must be reconsidered again, because of characteristics of mobile database system such as mobility and instability of wireless network. A new transaction model should be required for considering the characteristics, since especially a mobile computing environment is location-dependent, compared with the location transparency in a distributed computing environment. In other aspect, normally mobile host may be moving not in all space, but in some limited path. That is, a host is moving along the roads or the geographical features adjacent to the roads. The transaction processing should be considered not on the spatial coordinate but on the geographical features. In this paper, the feature based transaction processing model is proposed to process location-dependent transaction efficiently.

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A Recovery Mechanism for Server Failure in Database Systems based on Mobile computing Environments (이동 컴퓨팅 환경에 기반을 둔 데이터베이스 시스템에서 서버의 고장 회복 기법)

  • Jo, Jeong-Ran;Hwang, Bu-Hyeon
    • The Transactions of the Korea Information Processing Society
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    • v.6 no.1
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    • pp.1-10
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    • 1999
  • A mobile computing environment is one that support user's mobility through the wireless communication technology. Users access the database and get results what they want by running mobile transactions. To run the mobile transaction correctly and to maintain the consistency I database, we need a concurrency control method to schedule transactions, a caching method to manage the cache, and a recovery method to construct a fault tolerant system. A mobile computing system is based on the existing distributed system, but we can't use recovery methods of the existing distributed system directly because of the user's mobility and the features of wireless media. So this paper presents a recovery mechanism to construct a fault tolerant mobile computing systems. Especially. we develop and analyze a recovery algorithm for server failure among types of failure which can arise in mobile computing environments.

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Development of the Management Tool for S&T information in distributed retrieval database (분산 저장된 과학기술정보 서비스를 위한 검색 데이터베이스 관리 도구의 설계 및 개발)

  • Lee, Seok-Hyoung;Yoon, Hee-Jun;Yeo, Il-Yeon;Choi, Sung-Pil;Yoon, Hwa-Mook
    • Proceedings of the Korea Contents Association Conference
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    • 2006.11a
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    • pp.677-681
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    • 2006
  • In this paper, we suggest the GUI Management Tool, named K-Manager, for management and service of science and technology information that stored in distributed retrieval databases. Generally, it must be adapted retrieval database system for web based S&T contents service. But, It is inconvenient contents manager or the system administrator controls information easily, because it does not support the S&T information management process like TOAD, which can use for the relation database, in information retrieval database system. Using K-Manager, content manager can process the S&T content and system manager can manage the databases easily. The proposed tool active controls information effectively which is stored in the distributed retrieval database which guarantee the safety management of the contents stored in database and operate retrieval with efficient performances. Our tool consists of two sub systems, one is content manager, the other is database manager for YESKISTI based on KRISTAL-IRMS.

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The Development of Distributed Tool Management System tailored for Injection Mold Production (사출금형 생산을 위한 분산관리형 공구관리 시스템의 개발)

  • 정태성;양민양;변철웅
    • Journal of the Korean Society for Precision Engineering
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    • v.20 no.4
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    • pp.118-127
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    • 2003
  • An effective tool management system is one of the keys to maximizing the benefits of a computer integrated manufacturing (CIM). Tool management systems, however, are often tailored to the requirement of a highly automated system. Therefore, a different approach is needed for small and medium sized mold shops. This work deals with the implementation of tool management system for milling operations in small and medium sized CIM environment of injection mold production. In this paper, a distributed management approach is proposed for efficient tool management in relatively small machining shops in mold industry. And the design and the functions of the developed system are described.

The Design of Process-Engine for Distributed Workflow Management System based on Web (웹기반 분산워크플로우 관리시스템의 프로세스 엔진 설계)

  • Lee, Heon;Park, Kyoo-Seok
    • Journal of Korea Multimedia Society
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    • v.4 no.5
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    • pp.377-389
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    • 2001
  • It has a tendency to build Workflow Systems based on the web with the spread of web environment. The important function in Workflow Systems are to automatize job flow according to the predefined regulations, procedures or conditions. Hence, there needs to consider excluding passive jobs, supporting GUI and a migratory information processing for information flow. Distributed Workflow System for workflow of a distributed service system should perform transfer control and Fault-Tolerance between tasks based on process logic, and real time processing. However, the existing mail systems being used are just for transmission and it doesn't fit to automatize job flow. To solve the matter, there needs a Distributed Workflow Engine to design workflow and automatize its control. In this paper, we design a web browser with graphic interface using web mail, a browser creating a script code for a procedural performance. Also, we design a Process-engine has a Preprocessor which tolerates process scheduler for task transaction or server node's faults on distributed environment. The proposed system enhances the reliability and usability of a system reduces the cost rather than a workflow system based on database, for they execute as proxy for a server's fault or suers' absence.

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Performance Evaluation for Scheduling Policies on a Realtime Database (실시간 데이터베이스에 대한 스케쥴링 정책의 성능 평가)

  • Kim, Suhee;Han, Kwangrok;Kim, Hwankoo;Son, Sang-Hyuk
    • Convergence Security Journal
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    • v.4 no.3
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    • pp.57-82
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    • 2004
  • The confluence of computers, communications, and databases is quickly creating a distributed database where many applications require real-time access to temporally consistent sensor data. We have developed an object-oriented real-time database system called BeeHive to provide a significant improvement in performance and functionality over conventional non-real-time database and object management systems. In this paper, the performance of two data-deadline cognizant scheduling policies EDDF and EDF-DC and the baseline EDF policy with/without admission control are evaluated through extensive experiments on BeeHive. The ranges where data-deadline cognizant scheduling policies are effective and where admission control plays a role are identified.

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Networked Robots in the Informative Spaces

  • Kim, Bong-Keun;Ohara, Kenichi;Ohba, Kohtaro;Tanikawa, Tamio;Hirai, Shigeoki;Tanie, Kazuo
    • 제어로봇시스템학회:학술대회논문집
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    • 2005.06a
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    • pp.714-719
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    • 2005
  • In this paper, the informative space is proposed to implant ubiquitous functions into physical spaces. We merge physical and virtual spaces through the space structurization using an RFID system, and solve the space localization and mapping problem for a robot to navigate through the distribution and synthesis of information and knowledge. To distribute knowledge flexibly and reliably to changing environment and also to develop a system which allows a robot to invoke and merge the distributed knowledge more freely, we employ a novel approach of knowledge management based on Web services. The proposed method is verified by building a physical space with two kinds of RFID tags and a virtual space with knowledge database based on Web services.

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