• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.7
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• pp.1344-1356
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• 2009

The DDS (Data Distribution Service) is a data-centric communication technology that provides an efficient communication service that supports a dynamic plug & play through an automatic setting of participants' location information for each data (Topic) by using DDS discovery technique. This paper proposes the hierarchical-structured DDS discovery technique (SPDP-TBF) suitable for the large-scale distributed systems by comparing and analyzing the existing DDS discovery techniques in terms of performance and problem areas. The proposed SPDP-TBF performs the periodic discovery of the involved participants only by having separate hierarchical managers which take charge of the registration and search (of participants) so that a participant sends its information to the related participants only, and it enhances the effectiveness of the message transfer. Moreover, the proposed SPDP-TBF provides the improved scalability by performing the hierarchical discovery through hierarchical manager nodes so that it can be applied to the large-scale distributed system.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.9 no.2
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• pp.123-128
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• 2009

In ubiquitous computing environments, service discovery to search for an available service is an important issue. In this paper, we propose an efficient service discovery scheme that is combined a node id-based clustering service discovery scheme and a P2P caching-based information spreading scheme. To search quickly a service, proposed scheme store key information in neighbor's local cache and search services using it's information. We do not use a central look up server and do not rely on flooding. Through simulation, we show that the proposed scheme improves the performance of response time and network load compared to other methods.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.9B
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• pp.947-954
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• 2009

In mobile ad hoc networks, service discovery to search for an available service is an important issue. In this paper, we propose an efficient service discovery protocol that is combined a dht-based service discovery scheme and a P2P caching-based information spreading scheme. Proposed scheme store key information in hashed zone and search services using it's information. To search quickly a service, it use its physical neighbors information which collected by 1-hop hello message between a node and its physical neighbors. We do not use a central look up server and do not rely on flooding. Hence, it uniquely balanced all node's load in mobile ad hoc networks and reduced the number of messages exchanged, network load and response time. The simulation results show that our protocol outperforms DHT-based and flooding protocols.

• Proceedings of the Korea Information Processing Society Conference
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• 2004.05a
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• pp.609-612
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• 2004

유비쿼터스 환경은 인간이 생활하는 각종 기기들에 컴퓨팅 능력과 네트워킹 능력을 가지고 상호간에 정보를 교환하며 서비스를 제공하는 환경을 말한다. 이러한 유비쿼터스 환경이 구축되기 위해서는 컴퓨팅 인프라 및 네트워킹 인프라를 기반으로 다양한 서비스 프레임워크가 지원되어야 한다. 여러 서비스 프레임워크에서 중요한 한가지로 서비스 및 자원에 대한 디스커버리 엔진을 들 수 있다. 본 논문에서는 유비쿼터스 환경에서 이동 에이전트를 이용하여 효율적인 디스커버리 기법을 제안한다. 본 기법을 이용하면 빠른 서비스의 검색뿐만 아니라 서비스 목록들의 일관성을 유지해 높은 신뢰성을 제공할 수 있다.

• Proceedings of the Korean Society of Computer Information Conference
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• 2015.01a
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• pp.159-161
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• 2015

서비스 디스커버리는 대부분의 분산시스템 및 서비스 지향 아키텍처의 핵심 구성요소다. 실시간 시스템 기반에서 서비스 위치는 자주 변경될 수 있는데, 이 때 서비스 중단 문제가 발생할 수 있다. 이를 방지하기 위해서 동적인 서비스 등록과 서비스 디스커버리 기법이 매우 중요하다. 본 논문은 서비스 중단 문제를 해결할 수 있는 몇 가지 오픈 소스 솔루션들을 소개한다. 각 솔루션들은 레지스트리 타입에 따라 크게 범용 레지스트리와 단일 목적용 레지스트리로 나눌 수 있다. 각 솔루션들의 기능을 서로 비교함으로써 사용자로 하여금 자신의 요구사항에 적합한 솔루션을 선택하는데 도움이 되고자 한다.

• Proceedings of the Korea Information Processing Society Conference
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• 2005.05a
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• pp.581-584
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• 2005

에이전트 시스템(agent system) 관련 기술은 이질적이고 분산된 환경에서 상호 운용성(interoperability)을 확보하기 위한 방법이 될 수 있다. 이런 에이전트 시스템의 국제 표준화를 진행해 나가고 있는 단체인 FIPA(Foundation for Intelligent Physical Agents)는 1996년 에 형성되었고, 이질적인 시스템간의 상호 운용성을 최대화하기 위해서 국제적으로 인정된 명세서를 정기적으로 발표하고 있다. 하지만 최근까지 FIPA 표준안은 모바일 ad-hoc네트워크와 같은 환경을 고려하지 못하고 있다. 이러한 환경에서 에이전트는 이질적인 네트워크들에서 제공하는 서비스들을 이용할 수 없다. 이러한 문제점에 초점을 맞추어 본 논문에서는 FIPA 표준을 참고하여 만든 FIPA-OS(Foundation for Intelligent Physical Agents Open Source) 를 수정한 에이전트 플랫폼을 제공한다. 우리는 이러한 에이전트 플랫폼을 이용하여 이질적인 환경에서 제공하는 서비스들에 대한 상호운용성과 에이전트 플랫폼 안에 DM(Discovery Middleware)을 추가하여 확장성을 보장한다. DM은 에이전트가 ad-hoc 네트워크 안에서 동작하는 서비스 디스커버리 기법들을 사용하여 서비스들을 찾고 생성할 수 있게 도와준다. 우리는 다양한 서비스 디스커버리 기법 중 UPnP (Universal Plug and Play)와 LSD (Lightweight Service Discovery Protocol)를 이용하여 DM을 구현하였다. UPnP는 UPnP 포럼에서 개발된 서비스 디스커버리를 위한 프로토콜의 집합이며 LSD는 우리가 만든 모바일 ad-hoc 네트워크에서 동작하는 새로운 서비스 디스커버리 프로토콜로 캐쉬 관리를 강조하여 개발하였다. 우리가 제안하는 DM을 이용하여 수정된 에이전트 플랫폼에서 UPnP와 LSD의 장비에서 제공되는 서비스들을 상호간 이용 할 수 있다.

• Journal of the Korean Society for Library and Information Science
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• v.54 no.2
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• pp.399-417
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• 2020

In this study, we tried to analyze the relative importance of features for various functions provided by Discovery. We identified a total of 36 assessment items in five categories including contents, search function, serendipity, interactivity, and ease of use based on literature review. In order to objectively evaluate the relative importance of each evaluation element, an AHP technique was adopted. As a result, 'Easy of use' received the highest weighted value among the five categories, followed by 'contents', 'search function', 'interactivity', and 'serendipity'. In addition, among all the 36 assessment items, 'Quality of data for central index' had higher weighted value. These findings can be used as basic data to adopt a discovery tool for libraries.

• Journal of the Korea Society of Computer and Information
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• v.14 no.12
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• pp.109-117
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• 2009

In this paper, we propose an efficient service discovery scheme that combines peer-to-peer caching advertisement and node ID-based selective forwarding service requests. P2P caching advertisement quickly spreads available service information and reduces average response hop count since service information store in neighbor node cache. In addition, node ID-based service requests can minimize network transmission delay and can reduce network load since do not broadcast to all neighbor node. Proposed scheme does not require a central lookup server or registry and not rely on flooding that create a number of transmission messages. Simulation results show that proposed scheme improved network loads and response times since reduce a lot of messages and reduce average response hop counts using adaptive selective nodes among neighbor nodes compared to traditional flooding-based protocol.

• Communications of the Korean Institute of Information Scientists and Engineers
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• v.22 no.3
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• pp.6-17
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• 2004

• KIPS Transactions on Computer and Communication Systems
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• v.6 no.6
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• pp.281-288
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• 2017

In Smart-cities, various types of integrated services must be linked to provide services to applications. Therefore, flexibility must be ensured between services so that various services can be efficiently provided. In order to secure the flexibility among services, it is very important to have a function to dynamically discover and invoke a desired service by searching for a semantic service by reflecting a recognized context through real-time context-aware in smart-cities. To date, quite a number of semantic service discovery techniques have been developed. However, they have not been verified as suitable for use in the smart-city domain. In this study, we tried to verify the existing ones to use a suitable one. We tested most of existing semantic service discovery techniques, but we found that none of them is suitable to our research. Therefore, we developed our own semantic service discovery technique. This paper introduces our work and presents the performance evaluation results that demonstrate that our developed works well and show good performance. For the performance evaluation, the experimental system was actually constructed and the real performance was measured. In the experiment, we implemented the semantic service discovery scenario that dynamically searches and calls the services needed to provide fire accident management services in smart cities.