• Journal of KIISE:Computing Practices and Letters
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• v.14 no.2
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• pp.143-157
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• 2008

Ubiquitous Web Services is able to be specified future Web Services technology for connecting with various application services in any device and network environments. The devices, in ubiquitous environment, have dynamic characteristic such as location and statuse. So, we must support methods of dynamic service discovery in ad-hoc network. There are many related works at transaction, security, QoS, semantic and Web Services composition with various fields. Recently, the studies are interested in the Ubiquitous by development of computing and network technology. However, they are an early stage. For this reason, in this paper, we propose a WSUN(Web Services on Universal Networks) for Ubiquitous Web Services. It is a SOA based framework. And this paper extracts necessity of WSUN environment from scenario. The framework is composed of US Broker(Universal Service Broker). It is designed for satisfying the conditions and supports dynamic service discovery using a US Registry (Universal Service Registry). Consequently. clients are able to discover and use Universal Service by protocol stack of the US Broker for Web Services. And it is a strong point which supports interoperability between heterogeneous networks.

• The Journal of the Korea Contents Association
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• v.9 no.10
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• pp.32-39
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• 2009

Semantically-operated services, which is different from Web services or semantic Web services with semantic markup, can be defined as the services providing search function or reasoning function using ontologies. It performs a pre-defined task by exploiting URI, ontology classes, and ontology properties. This study introduces a method for pipelining semantically-operated services based on a semantic broker which refers to ontologies and service description stored in a service manager and invokes by user constraints. The constraints consist of input instances, an output class, a visualization type, service names, and properties. This method provides automatically-generated service pipelines including composit services and a simple workflow to the user. The pipelines provided by the semantic broker can be executed in a fully-automatic manner to find a set of meaningful semantic pipelines. After all, this study would epochally contribute to develop a portal service by ways of supporting human service planners who want to find specific composit services pipelined from distributed semantically-operated services.

• Journal of KIISE
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• v.42 no.6
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• pp.807-816
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• 2015

The Internet of Things (IoT) has recently been showered with much attention worldwide. Various kinds of devices, communicating with each other in the IoT, demand multiple communication technologies to coexist. In this environment, mobile devices may utilize the vertical handover between different wireless radio interfaces such as Wi-Fi and Bluetooth, for efficient data transfer. In this paper, an IoT broker is implemented to support the vertical handover, which can also support and manage heterogeneous devices and communication interfaces. The handover is activated based on RSSI, Link Quality values, and real time traffic. The experimental results show that the proposed handover system substantially improves QoS in Bluetooth and reduces power consumption in mobile devices as compared with a system using only Wi-Fi.

• Proceedings of the Korea Multimedia Society Conference
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• 1998.10a
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• pp.344-349
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• 1998

본 논문에서는 최근 인터넷이 직면하고 있는 용량과 속도 저하와 같은 여러 가지 문제점을 해결하고, ATM 기반의 초고속 정보통신망의 이용을 활성화하기 위해 ATM 망을 하부구조로 하는 연동게이트웨이 시스템의 구조와 기능을 정의한다. 그리고 연동게이트 시스템의 서비스 브로커 기능을 통해 멀티미디어 서비스 컨탠츠 사용자가 선택함으로써 사용자에게 보다 광범위하고 다양한 서비스를 제공받을 수 있는 기회를 부여하고, 서비스 제공자에게는 서비스 경쟁력을 향상시킬 수 있는 방안을 모색하였다.

• Proceedings of the Korea Information Processing Society Conference
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• 2005.11a
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• pp.499-502
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• 2005

국가GIS사업 및 관련사업을 통해 다양한 지리정보가 생산되었으며, 다양한 분야의 사용자에 의해 구축 활용되는 지리정보의 특성에 따라 전국에 분포되어 관리되고 있다. 이러한 지리정보가 사장되지 않고 목적에 맞게 효율적으로 활용되기 위해서는 다양한 콘텐츠 확보가 이기종간 공동활용이 선행될 필요가 있다. 따라서 본 연구에서는 서로 다른 시스템 환경에서 지리정보를 연계하여 활용할 수 있도록 카탈로그 모듈, 브로커 모듈, 맵브라우저 모듈, 지리정보등록 모듈 등을 구현하고 Informix, Oracle, GMS, ZEUS 등 여러 가지 조합이 도출될 수 있는 시스템을 대상으로 검증실험을 하였다. 본 연구에서 도출된 모듈을 적용하여 데이터 연계의 제약조건인 DMBS, 공간DBMS 영향을 최소화함으로써 지리정보공유 활성화에 기여할 수 있다.

• Journal of KIISE
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• v.42 no.5
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• pp.591-600
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• 2015

SLA (Service Level Agreement) is an essential factor that must be guaranteed to provide a reliable and consistent service to user in cloud computing environment. Especially, a contract between user and service provider with SLA is important in an environment using a cloud service brokerage. The cloud computing is classified into IaaS, PaaS, and SaaS according to IT resources of the various cloud service. The existing SLA is difficult to reflect the quality factors of service, because it only considers factors about the physical Network environment and have no methodological approach. In this paper, we suggested a method to specify the quality characteristics of software and proposed a mechanism and structure that can exchange SLA specification between the service provider and consumer. We defined a meta-model for the SLA specification in the SaaS level, and quality requirements of the SaaS were described by the proposed specification language. Through case studies, we verified proposed specification language that can present a variety of software quality factors. By using the UDDI-based mediation process and architecture to interchange this specification, it is stored in the repository of quality specifications and exchanged during service binding time.

• Proceedings of the Korean Information Science Society Conference
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• 2006.10a
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• pp.287-290
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• 2006

본 논문에서는 TMO 엔진과 객체 간 통신을 위한 채널 기반의 분산 IPC로 구축된 분산 컴퓨팅 서비스에, 동적으로 TMO 분산 실시간 객체를 추가하거나 제거하기 위한 프레임워크를 설계 구현하였다. 개발된 프레임워크는 분산 TMO 객체의 동적 구성 변경을 위한 채널의 접속 정보 관리, QoS 관리를 위한 스케줄링 및 채널 할당 정보 관리 등의 자원 관리를 동적으로 수행하여, 접속을 원하는 신규 TMO에게 접속에 필요한 정보의 제공과 중계를 담당하는 접속 브로커의 역할을 한다. 위와 같은 기능은 분산 실시간 객체 TMO를 위한 커널인 TMO-Linux 상에 구현되었다.

• KIISE Transactions on Computing Practices
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• v.20 no.12
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• pp.664-669
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• 2014

As the prevalence of cloud computing increases, various cloud service types have emerged, such as IaaS, PaaS, and SaaS. The growth and diversification of these cloud services has also resulted in the development of technology for cloud service brokers (CSBs), which serve as intermediate cloud services that can assist cloud tenants (users) in deploying services that fit their requirements. In order to broker cloud services, CSBs require the specification of structural models in order to facilitate the analysis and search for cloud services. In this study, we propose a variability-based service analysis model (SAM) that can be used to describe various cloud services. This model is based on the concept of variability in the software product line and represents the commonality and variability of cloud services by binding variants to each variation point that exists in the specification, quality, and pricing of the services. We also propose a virtual cloud bank architecture as a CSB that serves as an intermediate to provides tenants with appropriate cloud services based on the SAM.

• Journal of KIISE
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• v.42 no.11
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• pp.1361-1371
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• 2015

Depending on the increase amongst various cloud services, the technology of the Cloud Service Broker (CSB) to find the most appropriate services to meet the needs of cloud service consumers has emerged. In order to advance for cloud services to be used through the CSB, it is important to ensure the quality level that meets the demands of consumers through a negotiation process based on the Service Level Agreement (SLA). However, quality metrics of cloud services are different from each other based on the measurement scale, which represents the quality level, and the calculation for each type of cloud services. Therefore, it is necessary to analyze the variability of the quality of cloud services and establish a SLA model for ensuring and improving the level of quality. In this paper, we analyze the quality metrics for the specific type of cloud services by applying the cross-cutting concept and propose a Virtual SLA (VSLA) meta-model.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.11
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• pp.2061-2066
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• 2016

Currently, cloud systems are not interoperable due to low interoperability between cloud systems as operators build up cloud environments with their own way. For example, users of the Google cloud system can not use the Microsoft (Microsoft) cloud system unless they go through an additional log-in process. In order for Google cloud system's users to use MS cloud system services, they must log in to the MS cloud system again after logging out of Google cloud system. In order to solve these problems, Cloud Service Broker(CSB) technology has emerged to resolve the interoperability problem between cloud systems, but many researches and developments are still needed. In this paper, we design an integrated user authentication system, which is a fundamental problem of cloud user interoperability among CSB (Cloud Service Broker) technologies, which is emerging as a service intervention technology of heterogeneous distributed cloud environment.