• Journal of the Korea Society for Simulation
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• v.12 no.3
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• pp.69-81
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• 2003

To manage a cluster of distributed server systems, a number of management aspects should be considered in terms of configuration management, fault management, performance management, and user management. System performance monitoring and reporting take an important role for performance and fault management. In this paper, we present distributed system architecture modeling of a performance monitoring and reporting tool. Modeling architecture of four subsystems are introduced: node agent, data collection, performance management & report, and DB schema. The performance-related information collected from distributed servers are categorized into performance counters, event data for system status changes, service quality, and system configuration data. In order to analyze those performance information, we use a number of ways to evaluate data corelation. By using some results from a real site of a company and from simulation of artificial workload, we show the example of performance collection and analysis. Since our report tool detects system fault or node component failure and analyzes performances through resource usage and service quality, we are able to provide information for server load balancing, in short term view, and the cause of system faults and decision for system scale-out and scale-up, in long term view.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.40 no.5
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• pp.964-973
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• 2015

Ship Area Network(SAN) can monitor the status of ship in real time and minimize the maintenance costs by connecting various devices to the network. In particular, among researches on SAN, Wireless Sensor Network using sensor nodes that is low-cost, low-power, and multifunctional has a number of advantages. In this paper, we propose cluster-based multi-channel algorithm considering the energy efficiency in wireless sensor network in a ship. The proposed algorithm shows the result of improvement of throughput and energy efficiency, because it reduces interference between clusters by using channel allocation algorithm that is distributed and dynamic.

• Proceedings of the Korea Water Resources Association Conference
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• 2010.05a
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• pp.1400-1404
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• 2010

In this study the flow duration curves and load duration curves for Nakdong river basin are analyzed. The TANK model is used as s hydrologic simulation model whose parameters are estimated from 8-days intervals flow data measured by Nakdong River Water Environment Laboratory. also in this study a Minimum Variance Unbiased Estimator(MVUE) is confirmed that it provides satisfactory load estimate. The Seven-Parameter Log Linear Model for estimating Total Organic Carbon(TOC) and Biochemical Oxygen Demand(BOD) loads in Nakdong river using a MVUE.

• Journal of the Korea Institute of Military Science and Technology
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• v.15 no.4
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• pp.381-389
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• 2012

In the existing naval combat system, integrated management is done based on subsystems that make up the system. The naval combat system, however, is a large-scale distributed system made up of subsystems of diverse heterogeneous environments. Although each of the subsystems can be easily managed because they are on the same platform, it is extremely difficult to integrate and manage as a single entity all subsystems that make up the naval combat system because the heterogeneous environments and distributed systems have to be taken into account. In fact, there hasn't been a technique available to integrate and manage subsystems that make up the naval combat system, until now. In this paper, the architecture of an integrated management system is designed and implemented to provide the user with various services. Furthermore, a system that can manage subsystems of the naval combat system in an integrated way is developed.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.10
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• pp.2235-2241
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• 2009

RFID and USN are major technology in Ubiquitous. RFID is an automatic identification method, relying on storing and remotely retrieving data using devices called RFID tags or transponders through RFID reader. USN is wireless sense network and monitoring environment conditions that is temperature, noise, pressure, oscillation. In this paper, we propose wireless sensor network system that is monitoring to optimize environment conditions.

• Proceedings of the Korean Information Science Society Conference
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• 2006.10a
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• pp.557-562
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• 2006

최근 기업환경에서는 분산되어 있는 정보를 통합하여 정보 공유의 필요성이 증가함에 따라 기존 레거시 시스템간의 협업을 하기 위한 상호 운용이 강조되고 있다. 독립적인 레거시 시스템의 상호 연결을 위해서는 플랫폼 이질성, 의미 이질성 등을 극복할 필요가 있다. 이러한 문제를 해결하기 위해 ISO/IEC 11179에서 진행하고 있는 XMDR을 이용하여 미들웨어를 설계하였다. 설계한 미들웨어를 레거시 시스템에 적용하여 데이터 공유 및 통합의 일관성을 유지할 수 있게 되었다. 하지만 설계된 미들웨어는 각 노드의 자원 상황과 작업 상황에 대한 조정기능이 없기 때문에 정보 활용의 효율성을 보장할 수 없다. 따라서 레거시 시스템을 관리하고 조정하는 방안이 필요하다. 본 논문에서는 정보를 요청하는 요청 에이전트와 정보를 제공하는 정보 에이전트간의 정확한 정보 교환을 할 수 있도록 조정하고, 각 레거시 시스템의 정보 모니터링과 작업 분배 및 로컬 노드의 자원 관리를 담당하는 협력 에이전트를 설계함으로써 통합된 정보를 효율적으로 활용할 수 있도록 한다.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.30 no.4
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• pp.215-221
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• 2022

본 연구는 민간항공 조종사 훈련 및 평가에 중요하게 고려되고 있는 8가지 핵심 역량 향상을 위한 기초자료 마련을 위해 수행되었으며, 그 중 가장 중요하다고 판단되는 상황인식(situation awareness) 및 작업부하 관리에 대해 분석하였다. 예비 조종사를 대상으로 항공기 접근 및 착륙 단계를 진행하는 동안 PM(pilot monitoring) 역할을 수행하며 인식하는 항공기 상황과 작업부하량에 대해 평가하였다. 평가 시나리오는 기본비행훈련장치(basic aviation training device)를 사용하여 지형적 상황인식, 공간/시간적 상황인식, 시스템 상황인식, 환경적 상황인식을 평가할 수 있는 요소로 구성하였으며, 모니터링 도중 의도적인 주의분산 상황을 추가하였다. 연구 결과, 전체 비행 단계에 대한 상황인식은 32.3%이고, 지형적 상황인식(60.3%)이 가장 높고, 시스템 상황인식(18%)이 가장 낮은 것으로 나타났다. NASA-TLX 평가방법으로 측정한 작업부하량은 10.8점(20점 만점)으로 나타났다. 또한, 기초공중항법학을 수강한 예비 조종사들이 대체로 높은 상황인식을 하였고, 작업부하 결과는 지형적 상황인식과 밀접한 상관관계를 가지고 있었다.

• Convergence Security Journal
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• v.23 no.1
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• pp.63-68
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• 2023

In this study, in relation to blockchain protocol and network security, we study the configuration of blockchain and encryption key management methods on smart contracts so that we can have a strong level of response to MITM attacks and DoS/DDoS attacks. It is expected that the use of blockchain technology with enhanced security can be activated through respond to data security threats such as MITM through encryption communication protocols and enhanced authentication, node load balancing and distributed DDoS attack response, secure coding and vulnerability scanning, strengthen smart contract security with secure consensus algorithms, access control and authentication through enhanced user authentication and authorization, strengthen the security of cores and nodes, and monitoring system to update other blockchain protocols and enhance security.

• Geophysics and Geophysical Exploration
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• v.9 no.1
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• pp.67-72
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• 2006

Injection of $CO_2$ into underground saline formations, due to their large storage capacity, is probably the most promising approach for the reduction of $CO_2$ emissions into the atmosphere. $CO_2$ storage must be carefully planned and monitored to ensure that the $CO_2$ is safely retained in the formation for periods of at least thousands of years. Seismic methods, particularly for offshore reservoirs, are the primary tool for monitoring the injection process and distribution of $CO_2$ in the reservoir over time provided that reservoir properties are favourable. Seismic methods are equally essential for the characterisation of a potential trap, determining the reservoir properties, and estimating its capacity. Hence, an assessment of the change in seismic response to $CO_2$ storage needs to be carried out at a very early stage. This must be revisited at later stages, to assess potential changes in seismic response arising from changes in fluid properties or mineral composition that may arise from chemical interactions between the host rock and the $CO_2$. Thus, carefully structured modelling of the seismic response changes caused by injection of $CO_2$ into a reservoir over time helps in the design of a long-term monitoring program. For that purpose we have developed a Graphical User Interface (GUI) driven rock physics simulator, designed to model both short and long-term 4D seismic responses to injected $CO_2$. The application incorporates $CO_2$ phase changes, local pressure and temperature changes. chemical reactions and mineral precipitation. By incorporating anisotropic Gassmann equations into the simulator, the seismic response of faults and fractures reactivated by $CO_2$ can also be predicted. We show field examples (potential $CO_2$ sequestration sites offshore and onshore) where we have tested our rock physics simulator. 4D seismic responses are modelled to help design the monitoring program.

• KIISE Transactions on Computing Practices
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• v.23 no.5
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• pp.310-315
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• 2017

In a centralized control structure, the software defined network controller manages all openflow enabled switched in a data plane and controls the telecommunication between all hosts. In addition, the network manager can easily deploy the network function to the application layer with a software defined network controller. For this reason, many methods for network management using a software defined network concept have been proposed. The main policies for network management are related to traffic Quality of Service and resource management. In order to provide Quality of Service and load distribution for network users, we propose an efficient routing method using a naive bayesian algorithm and transmission delay estimation module. In this method, the forwarding path is decided by flow class and estimated transmission delay result in the software defined network controller. With this method, the load on the network node can be distributed to improve overall network performance. The network user also gets better dynamic Quality of Service.