• 한국HCI학회:학술대회논문집
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• 2009.02a
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• pp.232-239
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• 2009

Emerging social networking services provide a new paradigm for human-to-human communication. However, these services are centralized and managed by single service provider. In this paper, we propose MicroPost, a decentralized event notification service architecture for social applications based on publish/subscribe model. In our design space, event brokers are structured as an overlay network which provides the substrate of distributed peer-to-peer lookup service for storing and retrieving subscriptions with hashed keys. Event clients interact with event brokers to publish or subscribe social messages over the wide-area network. Using XML standards, we present an efficient algorithm to forward events for rendezvous-based matching in this paper. In our design space, the cost of routing is O(${\omega}log_kN$), where N is the number of event brokers, ${\omega}$ is the number of meta-data obtained from event messages, and k is a constant, which is selected by our design, to divide the identifier space and to conquer the lookup of given key. Consequently, what we achieved is an asynchronous social messaging service architecture which is decentralized, efficient, scalable, and flexible.

• Journal of Satellite, Information and Communications
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• v.11 no.2
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• pp.1-7
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• 2016

In this paper, we propose contents authoring, management, and distribution technologies where the contents registered in secure storage through a content acquisition and authoring tool can be used as a common experience in smartphones, smart pads, and PCs. Currently, many people are producing and consuming various types of contents in bulk, and it is expected that real-time contents and old contents coexist as IoT(Internet of Things) technology is commonly deployed in the future. Therefore, we need to develop a differentiated service that can compete with global services in contents authoring and collaboration systems to create new markets. Accordingly, we implemented an authoring service platform to occupy cloud markets with high quality contents produced through collaboration.

• Proceedings of the Korean Information Science Society Conference
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• 2000.10c
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• pp.546-548
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• 2000

최근 네트워크 대역폭과 CPU의 처리 능력이 향상되고 인터넷 사용의 보편화됨에 따라 멀티미디어 데이터를 실시간으로 전송하고 재생하는 멀티미디어 스트리밍 프레임워크가 출현하게 되었다. 이에 서로 다른 하드웨어 플랫폼, 운영체제, 네트워크 환경에서의 상호 운용성(interoperability)을 제공하는 CORBA(Common Object Request Broker Architecture) 기반의 멀티미디어 스트리밍 프레임워크가 출현하고 있다. 현재 멀티미디어 서비스에서 QoS(Quality of Service)를 지원하기 위하여 사용자의 요구사항 반영 구조 연구, 서비스 지원 미들웨어 구조 연구, 통신 프로토콜 및 전송 시스템 등 부분적으로 QoS(Quality of Service)를 지원하는 연구가 진행되고 있다. 본 논문에서는 상호 운용성을 포함한 CORBA 환경에서 스트리밍 서비스 표준에 의한 시스템에 QoSM(QoS Manager)을 정의하고, 구성요소의 역할 및 맵핑 방법과 이를 위한 인터페이스를 제시한다.

• Journal of KIISE:Computer Systems and Theory
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• v.35 no.6
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• pp.237-247
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• 2008

A virtual screening is the process of reducing an unmanageable number of compounds to a limited number of compounds for the target of interest by means of computational techniques such as molecular docking. And it is one of a large-scale scientific application that requires large computing power and data storage capability. Previous applications or softwares for molecular docking such as AutoDock, FlexX, Glide, DOCK, LigandFit, ViSION were developed to be run on a supercomputer, a workstation, or a cluster-computer. However the virtual screening using a supercomputer has a problem that a supercomputer is very expensive and the virtual screening using a workstation or a cluster-computer requires a long execution time. Thus we propose a service-based virtual screening system using Grid computing technology which supports a large data intensive operation. We constructed 3-dimensional chemical molecular database for virtual screening. And we designed a resource broker and a data broker for supporting efficient molecular docking service and proposed various services for virtual screening. We implemented service based virtual screening system with DOCK 5.0 and Globus 3.2 toolkit. Our system can reduce a timeline and cost of drug or new material design.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 1998.06b
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• pp.79-84
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• 1998

This paper describes implementation of the core DSM-CC UU interface. It briefly describes the reference model for the DSM-CC and related standards that should be reviewed for the implementation. The Common Object Request Broker Architechture, Revision 2.0 (CORBA 2.0) is sued as a remote procedure call (RPC) scheme for the UU Interface. Entire system was implemented with C++ on Windows NT platforms. The implementation procedure has been decomposed ito two tasks. The first task is to implement the Naming Service for service navigation. The Naming Service is one of the CORBA Services that extend the core CORBA specification. A client GUI is implemented for easy navigation among various services. The second task is to construct multimedia server and client for a Video-on-Demand (VoD) system. MPEG-2 Transport Stream is transported via ATM AAL5 using the Windows Socket 2.2 ATM extension API. A GUI enables the user to navigate the service domain and select a program. After the selection the user can control the MPEG-2 stream with VCR-like buttons.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.1
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• pp.32-39
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• 2017

Recently, usage of mobile cloud services has been increasing. In particular, beyond the constraints of a single cloud computing service, studies on the multi-cloud have been actively pursued. A user must authenticate multiple cloud service providers to use additional cloud services in a multi-cloud. In previous studies, an authentication method using single sign-on (SSO) was not available in all cloud services. Cloud services will not be available when the SSO server is not available due to malicious attacks, because all authentication is done via the SSO server. Additionally, using a broker, there is a vulnerability that can expose authentication information for the service provider to a user who did not sign up. In this paper, we propose a secure user authentication protocol using biometric authentication that does not expose user information when using additional cloud services. The proposed protocol can use a single biometric authentication for multi-cloud services without storing authentication information in each cloud service. In terms of key stability (to ensure stability through the key agreement process and the key area), by disabling various attack methods, such as man-in-the-middle attacks and replay attacks, we provide secure mobile cloud services.

• KIPS Transactions on Software and Data Engineering
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• v.1 no.3
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• pp.137-148
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• 2012

Cloud service users request dedicated virtual computing resource from the cloud service provider to process jobs in independent environment from other users. To optimize this process with automated method, in this paper we proposed a framework for workflow scheduling in the cloud environment, in which the core component is the middleware called broker mediating the interaction between users and cloud service providers. To process jobs in on-demand and virtualized resources from cloud service providers, many papers propose scheduling algorithms that allocate jobs to virtual machines which are dedicated to one machine one job. With this method, the isolation of being processed jobs is guaranteed, but we can't use each resource to its fullest computing capacity with high efficiency in resource utilization. This paper therefore proposed a cost-efficient job scheduling algorithm which maximizes the utilization of managed resources with increasing the degree of multiprogramming to reduce the number of needed virtual machines; consequently we can save the cost for processing requests. We also consider the performance degradation in proposed scheme with thrashing and context switching. By evaluating the experimental results, we have shown that the proposed scheme has better cost-performance feature compared to an existing scheme.

• Spatial Information Research
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• v.12 no.2
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• pp.165-179
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• 2004

With the spread of wireless internet, the interest in mobile applications and services is increasing. Korea Wireless Internet Standardization Forum has been establishing the standards for mobile platform and map service in the wireless internet environment. This study aims to present a paragon of mapping middleware that plays the role of broker for wireless internet map service: in particular, it focuses on the interoperability with generic map servers. In this study, we developed a method for applying current map servers to the wireless internet map service, and analyzed the request/response structure of the map servers which have different operation characteristics in order to allow our middleware to fully utilize the functionalities of the map servers. The middleware we developed is composed of .NET-based XML Web Services: it has a lightweight module for image map and a map representation module for choropleth map, symbol map, chart map, etc. This mapping middleware is a broker between mobile client and generic map server, and supports .NET clients and Java clients as well. Its component-based interoperability grants the extensibility for the wireless internet dedicated map servers of the future in addition to the current generic map servers.

• Journal of the Korea Society of Computer and Information
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• v.14 no.10
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• pp.189-197
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• 2009

As the web service technology matures. research is focused on the composite web services that combine individual web services within an enterprise or between enterprises. Quality of service is the critical competitiveness factor in this mature technology stage where there are many services with similar functionalities differing only in some non-functional properties. Monitoring is the key component for the service quality management of a web service. A service quality monitoring system design using a broker is presented in this paper. OWL-S is used to specify the composite service process and a service policy (inputs and outputs of each service, quality attributes and values, etc.) built by WS-Policy is applied to the composite service process. If there is any discrepancy between the service policy and the monitored data, the service provider and the user are notified of it so as to take necessary measures. We have implemented a travel reservation system as an example of the presented design and the experimental results are shown. Average response time was monitored and the timeout policy was applied in the experiment.

• 한국HCI학회:학술대회논문집
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• 2006.02a
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• pp.368-373
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• 2006

본 연구는 다중 사용자가 존재하는 환경에서 각 사용자의 요구를 만족시킬 수 있는 서비스를 탐색하고, 선택된 서비스를 또 다른 사용자에게 제공되는 서비스와의 충돌 없이 제공하기 위한 서비스 선택 모델을 제안한다. 이 모델은 개별 사용자의 프로파일을 관리하는 사용자 에이전트(User Agent), 환경 정보를 인지하는 센서 매니저(Sensor Manager), 현 환경에 존재하는 기기들의 상태를 관리하는 장치 매니저(Device Manager), 그리고 개별 서비스들 사이의 충돌을 회피하고 서비스를 선택하는 서비스 브로커 (Service Broker) 의 4 가지 타입의 에이전트로 구성되어있다. 사용자 에이전트는 사용자의 과거 행동 정보로부터 사용자의 선호 패턴 및 프로파일을 추출해 낸다. 센서 매니저는 현재 환경에 존재하는 센서들로부터 전달받은 환경 정보를 조합함으로써, 현재 상황을 특징 짓는다. 사용자 에이전트와 센서 매니저로부터 현재 사용자의 특성과 현재 상황 정보를 전달 받은 서비스 브로커는 그 사용자가 현재 상황에서 어떠한 서비스를 필요로 하고 있는지 판단한다. 서비스 선택은 인지된 현재 상황에서 수행 가능한 서비스 목록 중에서, 사용자의 선호도 및 프로파일에 의해 적절한 서비스가 선택 된다. 이렇게 선택된 서비스는 그 서비스를 제공하기 위한 장치들의 작동을 제어함으로써 사용자에게 제공된다. 서비스를 위한 장치를 선택하고, 작업을 할당하기 위해 서비스 브로커는 장치 매니저를 통해 현재 사용 가능한 장치들의 상태와 제공하려는 서비스와 충돌을 일으킬 수 있는 장치들의 상태 정보를 받아와 서비스를 위한 최적의 장치들을 선택하고 동작에 대한 제어 정보를 작성한다. 이렇게 만들어진 서비스 제공 계획은 장치 매니저에게 전달되고, 장치 매니저는 계획에 따라 실제 장치들을 제어한다. 이상의 다중 에이전트 모델을 통해, 특정 상황에 존재하는 사용자 개개인에게 특성화된 서비스를 충돌 없이 제공할 수 있다.