• Proceedings of the Korean Information Science Society Conference
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• 1999.10c
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• pp.345-347
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• 1999

Payword 프로토콜은 전체적인 프로토콜의 수행 과정이 복잡하지 않고, 과도한 암호화 모듈을 사용하는 대신 단방향 해쉬 함수를 사용함으로써 전체 시스템의 속도가 빠르며, 대금을 지불하고 정산하는 방식에 있어 상당항 효율성을 가지고 있어 소액대금결제시스템으로 안성맞춤이다. 그러나 Payword 프로토콜은 프로토콜의 구조적인 결함으로 생길 수 있는 문제점을 가지고 있다. Payword 프로토콜에서 사용자는 상거래 행위에 참가하기 위해 Broker에게 계좌요구정보를 전송한 후, 그 결과로 Certificate를 받는다. 사용자는 전송 받은 Certificate를 기반으로 Commitment를 생성하고 이를 Vendor에 전송한다. Vendormss Commitment에 기반으로 하여 일정 기간동안의 사용자의 Payword 체인은 정당한 것으로 간주함으로 상거래 행위가 생긴다. 따라서 매우 빠르고 효율적인 상거래 행위가 진행될 수 있다. 그러나 사용자는 여러 Vendord와 거래하기 위해서는 Commitment를 각각의 Vendor에 전송하여야 한다. 이점을 악용하여 사용자는 자신이 Broker와 사용하기로 약정한 Payword 체인을 여러 Vendor에서 전부 사용할 수 있는 문제가 발생하게 된다. 본 논문에서는 이러한 사용자에 의한 악의적인 Payword의 사용을 방지하고, 보다 소액대금결제 시스템에 적합한 Payword 프로토콜을 개정한 Payword 프로토콜을 제안한다.

• Communications of the Korean Institute of Information Scientists and Engineers
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• v.24 no.3 s.202
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• pp.35-42
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• 2006

본 논문에서는 내장형 소프트웨어 시스템, 특히 로봇 소프트웨어를 위한 self-managed 소프트웨어 개발 프레임워크로서 SHAGE 프레임워크를 제안하였다. SHAGE 프레임워크는 소프트웨어를 실행시간에 동적으로 변경시킬 수 있도록 지원하는 여러 모듈로 구성되어 있다. Observer가 외부 상황을 관찰하고 관찰된 상황이 Architecture Broker로 전달되면 후보 아키텍처 재구성 전략을 검색하고 Component Broker가 구체화 컴포넌트들을 검색한 후 상황에 적절한 아키텍처 재구성 전략과 컴포넌트 구성을 Decision Maker가 선택한다. Reconfigurator가 선택된 전략과 컴포넌트 구성을 기초로 로봇의 아키텍처를 재구성한다. 적응행위를 Evaluator가 평가하고 그 결과를 Learner가 축적하여 나중에 Decision Maker가 사용할 수 있게 한다. 프레임워크의 효용성을 확인하기 위해서 실제 로봇을 이용한 사례연구를 수행하였고, 이 실험을 통해 적응 과정을 확인하였다. 로봇은 상황과 사용자의 피드백에 적응하였다.

• Proceedings of the Korean Information Science Society Conference
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• 2003.10a
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• pp.322-324
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• 2003

B2B 거래에 있어서 이기종 환경의 시스템들간의 상호 운용성을 향상시키기 위한 방법으로 기업간 거래문서를 XML문서로 보내는 방법이 제안되고 있다. 이 방법은 파트너들이 모두 XML문서를 주고받을 준비가 되어 있다면 효율적이지만 아직은 일부에서만 XML을 사용하고 있다. XML문서를 주고받으려면 파트너들이 모두 XML을 수용할 수 있도록 기존 시스템을 변경해야 하는 문제가 있다. 이러한 문제를 해결하기 위하여, 본 논문에서는 어떠한 형식의 메시지가 전송되더라도 보험 표준 XML인 ACORD로 변환하여 처리 할 수 있는 메시지 Broker 시스템을 구현하였다. Broker 시스템을 통한 메시지 변환/전송으로 많은 파트너의 다양한 요구를 유연하게 수용할 수 있을 것이다.

• Proceedings of the Korea Information Processing Society Conference
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• 2014.04a
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• pp.112-114
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• 2014

클라우드(cloud)를 이용한 응용 실행에서 클라우드 서비스 브로커 (cloud service broker, CSB)는 효과적인 자원 사용 및 서비스 수준 협약(service level agreement, SLA) 보장 등의 장점을 가진다. 따라서 본 논문에서는 CSB 를 통한 응용 실행에서의 가상 머신 (virtual machine, VM) 할당 기법들을 소개하며 BestFit (BF), WorstFit (WF), Modified BestFit (MBF), Modified WorstFit (MWF), Reserved Instance-aware Modified BestFit (M-MBF) 의 평균 VM 사용률을 비교한다.

• Proceedings of the Korea Information Processing Society Conference
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• 2012.11a
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• pp.239-240
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• 2012

When users access to use the computing resources in the cloud, they expect specific quality of service (QoS) which should be guaranteed by the service provider. Meanwhile, the service provider should adopt proper schemes to enhance the resource utilization. In this thesis, we propose the MapChem-Broker which aims to satisfy users' QoS requirements as well as enhance the resource utilization by controlling the provision of VM resources in the cloud. On the experimental cloud testbed, we compare the proposed scheme with an existing one for VM resource provisioning. Results show that the proposed scheme outperforms the existing one.

• Journal of KIISE:Computing Practices and Letters
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• v.15 no.10
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• pp.752-760
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• 2009

Emerging peer-to-peer systems benefit from the large amount of resources provided by many peers. However, many peer-to-peer systems or applications suffer from malicious peers and it is not guaranteed that peers are always online. Micropayment systems are accounting and charging mechanism for buying services, so we can apply them to solve these problems. In the past the majority of micropayment system uses a centralized broker but the problem with most existing micropayment system is a heavy load on the broker. For instance, when an owner of the coin is offline, the broker delegates the owner and handles payment messages. It occurs frequently because of characteristic of peer-to-peer system and is another load of the broker. In this paper we introduce DPay, a peer-to-peer micropayment system that uses distributed hash table (DHT) for storing encrypted payment messages and increases scalability and reduces the load of broker by removing downtime protocol. We show the idea of real-time double spending detection in DPay and report the results of several evaluations in order to compare DPay and other payment scheme. In simulation result, the load of broker in DPay is reduced by 30% on average of other previous payment scheme. We expect that DPay can apply various peer-to-peer systems because it provides a real-time double spending detection and stores more secure payment messages.

• Journal of Communications and Networks
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• v.7 no.2
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• pp.207-221
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• 2005

The proliferation of wireless local area networks (WLANs) offering high data rate in hot spot area have spurred the demand for possible WLANs and third-generation (3G) cellular network integration solutions as the initiative step towards 4G systems. This paper provides a novel architecture for seamless location-aware integration of WLANs into 3G cellular networks and also an analysis for the efficient handover techniques. We introduce location as a key context in secure roaming mechanism for context-aware interworking in 4G systems. The fast secure roaming with location-aware authentication is implemented at an entity called location-aware service (LAS) broker that utilizes the concepts of direction of user and pre-warming zone. The location-ware interworking architecture supports seamless roaming services among heterogeneous wireless networks including WLANs, wireless metropolitan area networks (WMANs), and 3G cellular networks. This paper also includes a description of procedures needed to implement efficient mobility and location management. We show how the LAS broker with pre-warming and context transfer can obtain significant lower latency in the vertical handover.

• Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
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• v.7 no.6
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• pp.621-634
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• 2017

This study is a study on the requirements, resources, and role of policy broker in the policy process. Particular attention was paid to two requirements of legitimacy (official authority, political support) and professionalism (information and expertise, skilled leadership) as the requirements of policy broker. This study analyzed the process of transforming the actor conflicts surrounding the media rep legislative process into a cooperative relationship by being mediated by a strong influential policy broker. Policy brokers can mediate opinions among participating actors and play a role in coordinating conflicting interests. In the mediarep policy process, the policy brokers were unable to resolve conflicts due to lack of legitimacy and expertise in the first phase (legislative grace period) and the second phase (legislative loophole). However, the legitimacy of the six subcommittees of the National Assembly (the legislative period) and the expertise of the Korea Communications Commission were able to succeed in policy-making by acting as a successful policy brokers through complementary activities.

• Journal of the Korean Society for information Management
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• v.13 no.2
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• pp.223-242
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• 1996

This study proposes an integration model of information retrieval systems using a standard distributed object computing technology in digital library environments. In the proposed integration model called DDIRIORB, the middleware broker based on CORBA is designed for the transparent access to the distributed information repositories and the consistent view of the information retrieval by applying 239.50 protocol. The DDIRIORB is an adaptable open architecture that allows for the following benefits : bibliographic and abstract information retrieval simultaneously, interoperability between application servers and clients, consistent view of search results, complexity reduction of integration interfaces, and easy to use.

• KIPS Transactions on Software and Data Engineering
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• v.4 no.4
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• pp.161-168
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• 2015

It is difficult to provide proper cloud services for cloud users, because the number of cloud services are increasing and the type of cloud services are diversifying. To overcome this problem, the concept of cloud service broker is presented to mediate cloud services between cloud providers and tenant. The most important role of cloud service broker is to finding cloud services that fulfill requirements of tenant. However, current existing cloud service broker conduct passive requirements analysis process with cloud service expert's assistance. In addition, the systematic functional and non-functional requirement analysis is insufficient. Therefore, we need the new methods for requirement analysis to find nearest service that matches with requirement of tenant. In this paper, we apply pairwise comparison from AHP method to analyze requirement automatically and systematically. It calculates score of service by comparing requirement with service specification, calculating importance rate, and so on.