• Proceedings of the IEEK Conference
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• 2003.07d
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• pp.1621-1624
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• 2003

As the entities participating Grid become larger, performance requirement for the LDAP-based GIS(Grid Information Service) goes beyond that provided by a stand-alone single LDAP server. This entails the exploration of distributed LDAP systems. This paper presents the performance evaluation respectively for a distribution-based and a replication-based LDAP model. The analysis is based on an analytic performance model for each distributed system which is obtained by applying the M/M/1 queuing model. The performance evaluation made to these analytic models reveals that the distribution-based and the replication-based model show a significant tradeoff in their performance with respect to the system size as well as the amount of system load.

• Journal of the Korean Data and Information Science Society
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• v.19 no.2
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• pp.645-655
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• 2008

As wireless connectivity is integrated into many handheld devices, streaming multimedia content among mobile ad-hoc peers is becoming a popular application. In this paper, we propose a dynamic service replication algorithm for providing guaranteed continuous streaming services to all nodes in mobile ad-hoc networks (MANETs). First, a MANET is comprised of logical grid hierarchy, and a streaming service is replicated to a lower server region of the logical grid hierarchy by considering the link availability between a mobile node and the streaming server within a server region or the popularity of the streaming service. We evaluate analytically the performance of the proposed algorithm, and compared with that of existing Qin's algorithm. Evaluation results show that our algorithm can achieve better streaming performance than Qin's algorithm. Therefore, the proposed algorithm not only improves the sharing availability of replicated streaming services but also controls efficiently the number of streaming service replications.

• The KIPS Transactions:PartD
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• v.13D no.7 s.110
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• pp.985-996
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• 2006

As the internet technologies develop, the geographic information system environment is changing to the web-based service. Since geospatial information of the existing Web-GIS services were developed independently, there is no interoperability to support diverse map formats. In spite of the same geospatial information object it can be used for various proposes that is duplicated in GIS separately. It needs intelligent strategies for optimal replica selection, which is identification of replication geospatial information objects. And for management of replication objects, OMG, GLOBE and GRID computing suggested related frameworks. But these researches are not thorough going enough in case of geospatial information object. This paper presents a model of location service, which is supported for optimal selection among replication and management of replication objects. It is consist of tree main services. The first is binding service which can save names and properties of object defined by users according to service offers and enable clients to search them on the service of offers. The second is location service which can manage location information with contact records. And obtains performance information by the Load Sharing Facility on system independently with contact address. The third is intelligent selection service which can obtain basic/performance information from the binding service/location service and provide both faster access and better performance characteristics by rules as intelligent model based on rough sets. For the validity of location service model, this research presents the processes of location service execution with Graphic User Interface.

• Journal of KIISE:Software and Applications
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• v.37 no.7
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• pp.503-517
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• 2010

Service-oriented computing, the effective paradigm for developing service applications by using reusable services, becomes popular. In service-oriented computing, service consumer has no responsibility for managing services, just invokes services what service providers are producing. On the other hand, service providers should manage any resources and data for service consumers can use the service anytime and anywhere. However, it is hard service providers manage the quality of the services because an unspecified number of service consumers. Therefore, service scalability for providing services with higher quality of services specified in a service level agreement becomes a potential problem in service-oriented computing. There have been many researches for scalability in network, database, and distributed computing area. But a research about a definition of service scalability and metrics of measuring service scalability is still not mature in service engineering area. In this paper, we construct a service network which connects multiple service nodes, and integrate all the resources to manage it. And we also present a service scalability framework for managing service scalability by using a mechanism of service migration or replication. In section 3, we, firstly, present the structure of the scalability management framework and basic functionalities. In section 4, we propose scalability enhancement mechanism which is needed to release functionality of the framework. In section 5, we design and implement the framework by using proposed mechanism. In section 6, we demonstrate the result of our case study which dynamically manages services in multi-nodes environment by applying our framework. Through the case study, we show the applicability of our scalability management framework and mechanism.

• Journal of the Korean Society for Nondestructive Testing
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• v.30 no.5
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• pp.489-496
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• 2010

The power generation and chemical industry have been subjected to further material degradation with long term operations and need to predict the remaining service life of components, such as reformer tube and steam turbine rotor, that have operated at elevated temperatures. As a non-destructive technique, replication method with reliable metallurgical life and microstructural soundness assessment has been recognized with strongly useful method until now. Developments of this method have variously accomplished by new quantitative approach, such as carbide analysis, with A-parameter and grain deformation method. An overview of replication, some new techniques for material degradation and life assessment were introduced in this paper. Also, on-site applications and its reasonableness were described. As a result of having analyzed microstructure by replication method, carbide approach was quantitatively useful to life assessment.

• Journal of the Korea Society of Computer and Information
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• v.26 no.4
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• pp.75-84
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• 2021

In this paper, we introduce InfoDID, a robust user information management service based on DID that manages user information reliably. Since blockchain technology provides an environment in which data can be handled transparently on a decentralized basis, various services using blockchain are currently being developed As the importance of user's personal information has recently emerged, the DID technology is receiving attention. The technology allows a user to control his or her information through decentralized identifiers, and various information management services are being tried based on the technology. Using blockchain-based DID technology, InfoDID reliably controls personal information requested frequently, helping users to provide their information to other services more conveniently. In addition, to support service continuity, InfoDID uses BR2K technique that provides robust execution of blockchain application services, so that even partial service failures can be systematically recovered. To facilitate this operation, we present a replication status monitoring tool that can continuously check the replication states of blockchain application services running in association with the BR2K technique such as InfoDID.

• The Plant Pathology Journal
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• v.17 no.1
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• pp.22-28
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• 2001

Barley yellow dwarf virus PAV (BYDV-PAV) has a 5.7-kb positive-sense single-stranded RNA genome that contains six open reading frames (ORFs). BYDV-PAV produces three subgenomic RNAs (sgRNAs). The largest of which encodes the coat, 17-kDa, and readthrough proteins from two initiation codons. To investigate the role of intergenic and 3'-proximal noncoding regions (NCRs) in coat protein (CP) expression and BYDV-PAV replication, a full-length infectious cDNA of the RNA genome of an Illinois isolate of BYDV-PAV was constructed downstream of the Cauliflower mosaic virus-35S promoter. Linear DNA molecules of these cDNAs were infectious, expressed the 22-kDa CP, and produced both genomic RNA sgRNAs in ratios similar to those observed in protoplasts inoculated with viral RNA. The portion of 5'NCR of sgRNA1 between ORFs 2 and 3 was not required for, but enhanced translation of CP from ORF3. Mutants containing deletions in the NCR downstream of ORF5 failed to replicate in oat protoplasts. These results indicate that an intact 3$^1$NCR is required for BYDV-PAV replication.

• ETRI Journal
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• v.29 no.3
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• pp.281-291
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• 2007

Wearable computers consisting of various small devices such as smart phones, digital cameras, MP3 players and specialized I/O devices in personal area networks will play an important role in future ubiquitous computing. In this environment, accessing user data is quite complex due to the dynamic and heterogeneous characteristics of the underlying networks. Moreover, since the amount of user data increases rapidly, automatic data backup management is also critical. To overcome these challenges, several studies have been conducted including our previously proposed file service system, PosCFS, which could be adapted to the requirements with a virtualization technique allowing per-user global namespace for managing and accessing data stored on physical storage spaces detected in PAN. In this paper, we present a smart file service framework, PosCFS+ which is an improved and extended version of our previous work. Performance improvement is made possible by redesigning the metadata management scheme based on database and keywords rather than ontology. In addition, the automatic data replication management is newly designed based on the OSD protocol.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.4
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• pp.795-804
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• 2009

An HSS(Home Subscriber Server) system requires a main-memory database on main-memory unit for the real-tine management of the subscriber information in the mobile communication service, in that the system controls not only basic data for handling calls of users, but also additional service data related to user authentication and operational data. Nonetheless, HSS-DBS system, requiring the reliability and stability, need more secure data store method and a back-up technique because the system have a long startup time and the big problem on the failures of main-memory. This paper proposes an efficient back-up replication technique, on the basis of enhancing the stability and performance of HSS system. The proposed shadowing back-up technique adopting the delayed recovery process, can help minimize the real-time back-up overloads by location registration, while the proposed backup replication method enables more stable system operations with replicating the data to remote server in real time.

• Journal of KIISE:Computer Systems and Theory
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• v.33 no.10
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• pp.746-758
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• 2006

Many objects existing on wide area environments have the replication characteristics according to how to categorize using their own names or properties. From the clients' requests, the existing naming and trading services have not supported with the binding service for replicated solver object with the same service type. For this reason, we present an integrated model that can support the selection of replicated object and dynamic binding services on wide-area computing environments. This model suggests provides not only location management of replicated objects but also active binding service which enables to select a least-loaded object on the system to keep the balance of load between systems. In this purpose, constructing both the service plan and model for support solver object's binding with replication property on wide area computing environments has been researched. In this paper, we showed the test environment and analyzed the performance evaluation of client/server binding procedures via integrated binding service in federation model and verified our model under the condition to see whether load balance can be applied to our model. For the performance evaluation of suggested wide area integrated binding service federation model, evaluated the integrated binding service of each domain and analyzed the performance evaluation of process for non-replication object's under federation model environment. Also, we analyzed the performance evaluation of the federation model between domains for wide area environment. From the execution results, we showed the federation model provides lowers search-cost on the physical tree structure of network.