• Journal of Korea Society of Industrial Information Systems
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• v.11 no.2
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• pp.48-62
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• 2006

In recent years, wireless sensor networks(WSNs) have emerged as a new fast-growing application domain for wireless distributed computing and embedded systems. Recent Progress in computer and communication technology has made it possible to organize wireless sensor networks composed tiny sensor nodes. Furthermore, ad-hoc network protocols do not consider the characteristics of wireless sensor nodes, making existing ad-hoc network protocols unsuitable for the wireless sensor networks. First, we propose power-aware routing protocols based on energy-centered routing metrics. Second, we describe power management techniques for wireless sensor nodes using the spatial locality of sensed data. Many nodes can go into a power-down mode without sacrificing the accuracy of sensed data. Finally, combining the proposed techniques, we describe an overall energy-efficient protocol for data collection. Experimental results show that the proposed routing protocol can extend the routing path lifetime more than twice. The average energy consumption per sensing period is reduced by up to 30%.

• Journal of KIISE:Software and Applications
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• v.27 no.8
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• pp.886-901
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• 2000

Verification of the safety of untrusted codes becomes an important issue in the mobile computing environment and the safety-critical software systems. Recently, it is very common to run the codes attached to the electronic mails or downloaded from the web browsers. We propose the verification method of the machine code property. The code producer delivers the machine code and its property, then the code consumer checks whether the delivered code satisfies the delivered property. The safety of source codes is verified by the well-defined compiler systems but the verification mechanism for machine codes is not well defined yet. We design an intermediate language etySECK and propose the verification method of the property of etySECK programs. And then we prove the soundness of our system which is the type system with effect extension.

• KIISE Transactions on Computing Practices
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• v.21 no.4
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• pp.290-298
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• 2015

This paper suggests a multi-agent message transport architecture based on the message-oriented middleware ZeroMQ. Compared with the other middlewares such as CORBA, Ice, and Thrift, ZeroMQ receives a good score in the evaluation of performance, QoS (Quality of Service), patterns, user friendliness, and resources. The suggested message transfer architecture borrowed many basic concepts like agent platform, AMS (Agent Management System), and MTS (Message Transfer System) from FIPA (Foundation for Intelligent Physical Agents) standard multi-agent specifications, and the architecture inherited the strength of the architecture from the multi-agent framework SMAF (Smart Multi-Agent Framework). The architecture suggested in this paper is a novel peer-to-peer architecture which is not known to the ZeroMQ community. In the suggested architecture, every MTS agent uses only one ZeroMQ router socket to support peer-to-peer communication among MTS agents. The suggested architecture can support closely collaborating software areas such as intelligent robots as well as the traditional application areas of multi-agent architecture. The suggested architecture has interoperability and scalability with the ZeroMQ devices and patterns.

• Journal of KIISE:Computing Practices and Letters
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• v.15 no.8
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• pp.591-595
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• 2009

Most existing routing protocols for object detection and tracking in wireless sensor networks concentrate on finding ways to detect and track one and more individual objects, e.g. people, animals, and vehicles, but they do not be interested in detecting and tracking of continuous objects, e.g., poison gas and biochemical. Such continuous objects have quite different properties from the individual objects since the continuous objects are continuously distributed across a region and usually occupy a large area, Thus, the continuous objects could be detected by a number of sensor nodes so that sensing data are redundant and highly correlated. Therefore, an efficient data collection and report scheme for collecting and locally aggregating sensing data is needed, In this paper, we propose the Continuous Object Tracking Mechanism based on Dynamic Rectangle Zone for detecting, tracking, and monitoring the continuous objects taking into account their properties.

• Journal of KIISE:Computing Practices and Letters
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• v.11 no.5
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• pp.416-426
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• 2005

A B2Bi system needs a message storage subsystem that efficiently logs and searches XML messages which have been sent from orreceived by it. XML database systems and XML enabled relational databases systems are not adequate as a message storage system because of their expensiveness and excessiveness in functionality. Storage schemes that split XML messages into database records are also unacceptable because of either low performance or implementation hardness. In this paper, we propose a storage scheme that can be applied to implement a message storage system based on a relational database system. In this scheme, messages are examined only through the index fields that have been registered for each message types. Therefore, the proposed storage scheme cannot support such a powerful search facility like XQL, but it provides high performance message legging and restricted search facility. There are three alternative database schemas to store the index fields. This paper compares the advantages and disadvantages of the three schemas through experimental tests.

• Journal of KIISE:Computing Practices and Letters
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• v.5 no.6
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• pp.758-770
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• 1999

최근 급속한 네트워크 기술의 발달로 이들에 대한 관리의 필요성이 제기되었고 이를 위해 SNMP와 CMIP등과 같은 표준이 등장하여 사용되어 왔다. 그러나 점점 더 다양하고 복잡한 네트워크가 형성되자 이들에 대한 효율적인 관리가 필요하게 되었다. 현재, TMN은 개념에 있어서 보편성 및 가장 일반화된 관리개념이며 최종적으로 도달할 네트워크 관리 개념을 포함하고 있다. CORBA는 분산환경에서 응용프로그램을 쉽게 구현할 수 있는 기반을 제공하고 있다. 따라서 이러한 두 가지 기술을 접목한 CORBA와 TMN을 통합하고자 하는 많은 연구가 진행되고 있다. 본 논문에서는 현재의 CORBA/TMN 통합에 대한 연구를 바탕으로 효율적인 네트워크 통합 관리 구조를 정의하고 TMN의 기능중 Alarm Surveillance를 구조에 맞춰 구현하였다. 구현된 Alarm Surveillance System은 다양한 대리자들로부터 보고되는 여러 형태의 Alarm 정보에 대해, 처리 및 운용자에 대한 보고수행 등을 일관성 있게 처리하고 있는 것을 보여주고 있다. 따라서 제시된 Alarm Surveillance System은 사용자에게 일관성 있는 관리행위를 제공함으로써 다양한 관리구조가 적용된 복잡한 네트워크 관리를 제공할 수 있다. 또한 전체 네트워크로부터 필요한 통계분석을 위한 자료 수집 등의 편의를 제공할 것이다.Abstract Recently, due to the rapid development of network technology, the need for the network management appeared. So two representative standardards, SNMP and CMIP, have been applied to many network management system. But the more complex and vaious network are constructed, the demand for more efficient network management technology grew bigger. Currently, TMN technology is beginning to be widely applied to the management of networks. CORBA has been widely adopted for developing distributed systems in many areas of information technology. CORBA provides the infrastructure for the interoperability of various object-oriented management applications in a distributed environment, and, recently there have been world-wide research for the integration of CORBA within a TMN framework. Many attempts have been made to enable network management using CORBA techonology and some are working on already. This paper defines the architecture for integrated network management based on current CORBA/TMN integration technologies and then presents the design and implementation for alarm surveillance system which was applied to the defined architecture. The prototype implementation was done using IONA orbix. The proposed integrated network management framework will provide users with consistent management operations and ability to manage complex and various networks and to gather statistical data from those networks.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.19 no.3
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• pp.25-32
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• 2019

The core of the block chain technology is solving the problem of agreement on double payment, and the PoW, PoS and DPoS algorithms used for this have been studied. PoW in-process proofs are consensus systems that require feasible efforts to prevent minor or malicious use of computing capabilities, such as sending spam e-mail or initiating denial of service (DoS) attacks. The proof of the PoS is made to solve the Nothing at stake problem as well as the energy waste of the proof of work (PoW) algorithm, and the decision of the sum of each node is decided according to the amount of money, not the calculation ability. DPoS is that a small number of authorized users maintain a trade consensus through a distributed network, whereas DPS provides consent authority to a small number of representatives, whereas PoS has consent authority to all users. If PoS is direct democracy, DPoS is indirect democracy. This study aims to contribute to the continuous development of the related field through the study of the algorithm of the block chain agreement.

• KNOM Review
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• v.21 no.2
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• pp.46-52
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• 2018

For data-intensive scientific workflow application experiments that leverage the cloud computing environment, large amounts of data can be distributed across multiple data centers in the cloud. The generated intermediate data can also be transmitted through access between different data centers. When the application is executed, the execution result is changed according to the location of the data since the intermediate data generated is used. However, existing data placement strategies do not consider the characteristics of scientific applications. In this paper, we define a data-intensive tasks and propose runtime data placement in that interval. Through the proposed data placement scheme, we analyze the scenarios considering the number of times in the data intensive tasks defined in this study and derive the results. In addition, performance was compared by analyzing runtime data placement times and runtime data placement overhead.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.18 no.4
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• pp.111-122
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• 2008

Web service is defined to support interoperable machine to machine interaction over a network and defined as distributed technologies. Recently in web service environment, security has become one of the most critical issues. An attacker may expose user privacy and service information without authentication. Furthermore, the users of web services must temporarily delegate some or all of their behalf. This results in the exposure of user privacy information by agents. We propose a delegation model for providing safety of web service and user privacy in ubiquitous computing environments. In order to provide safety of web service and user privacy, XML-based encryption and a digital signature mechanism need to be efficiently integrated. In this paper, we propose web service management server based on XACML, in order to manage services and policies of web service providers. For this purpose, we extend SAML to declare delegation assertions transferred to web service providers by delegation among agents.

• Proceedings of the Korea Water Resources Association Conference
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• 2023.05a
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• pp.453-453
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• 2023

상수관망의 수질사고와 이상상황 발생시 대응을 위해서는 급수구역에 설치되어 있는 자동수질측정기, 정밀여과장치, 재염소주입설비, 자동드레인 등의 계측·제어설비들 간의 유기적인 정보공유를 통한 제어를 필요로 한다. 스마트 상수관망 운영플랫폼은 이러한 인프라 시설의 운영방안을 고려하여 분산되어 있는 계측데이터를 통합감시 및 제어하는 시스템으로 개발되었다. 상수관망 운영플랫폼은 능동형 분석 제어기술을 도입하여, 스마트 상수관망 인프라 설비를 최적제어할 수 있도록 구현하였다. 통합운영 플랫폼은 PostgreSQL, PostGIS, GeoServer, OpenLayers 등의 기술을 활용하여 개발하였다. 플랫폼은 계측감시, 시설관리, 운영제어 등의 기능으로 구성되며, 상수도 업무지원을 위한 관망해석 및 네트워크 분석 기능을 지원한다. 본 시스템은 스마트 상수도 구축사업을 통해 구축한 유량·수질모니터링 장비와 수질관리를 위해 도입된 재염소, 자동드레인 설비의 운영상태를 실시간 조회하는 모니터링 프로그램과, 관망해석 프로그램 그리고 대상설비의 최적제어를 위한 운영관리 프로그램으로 구성되어 있다. 모니터링 프로그램은 현장에서 측정되고 있는 유량, 수압, 수질, 펌프운전 등의 상태를 실시간으로 감시하고 클라우드 데이터베이스에 저장·관리하는 기능을 수행한다. 관망해석 프로그램은 EPA_Net모형과 연계되어 관망수리·수질해석을 수행하는 부분으로 재염소설비의 염소 추가주입이나 자동드레인을 통한 배제시 나타나게되는 관의 수리·수질변화를 클라우드 컴퓨팅 환경에서 분석하고 결과를 가시화 하는 기능을 갖고 있다. 운영관리 프로그램은 재염소 주입이 필요할 경우 주입량의 산정하는 부분과 관망 파손이나 수질사고 발생시 최적 단수예상지역을 도출하는 기능을 보유하고 있다. 향후 스마트 상수관망의 능동형 수질관리를 추진하는 지자체에 도입하여 인프라운영관리 기술 확보 및 수질관리 능력 개선과 실시간 감시 및 위기 대응능력 향상에 기여할 것으로 기대된다.