• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.10a
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• pp.492-496
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• 2002

We present the web-based remote monitoring system using distributed object technology. In order to provide the desired functionality, the system has used CORBA(Common Object Request Architecture) and Java Servlet to implement the integrated distributed object environment. It converts the existing standalone machine monitoring system into web-based machine monitoring system. It consists of applet program, CORBA server and CORBA client. The usefulness of our system will be illustrated by the application to ICM(Integrated Condition Monitoring) System developed by KIST Tribology Center.

• The KIPS Transactions:PartA
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• v.11A no.3
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• pp.181-188
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• 2004

PDF(Parallel/Distributed Processing) is an internet-based parallel/distributed processing system that utilizes resources from hosts on the internet in idle state to perform large scale application through parallel processing, thus decreasing the total execution time. In this paper. do propose an adaptive method to be changed network environment at any time using realtime monitoring of host. It is found from experiments that parallel/distributed processing has better performance than its without monitoring as an adaptive strategy, which copy with task delay factor by overload and fault of network, be applicable to the cockpits of task allocation algorithm in PDP.

• Structural Monitoring and Maintenance
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• v.7 no.1
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• pp.1-12
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• 2020

Railway tracks are the direct supporting structures of the trains, which are vulnerable to produce large deformation under the temperature stress or subgrade settlement. The health status of track is critical, and the track should be routinely monitored to improve safety, lower the risk of excess deformation and provide reliable maintenance strategy. In this paper, the distributed optical fiber sensor was proposed to monitor the continuous deformation of the track. In order to validate the feasibility of the monitoring method, two deformation monitoring tests on one steel rail model in laboratory and on one real railway tack in outdoor were conducted respectively. In the model test, the working conditions of simply supported beam and continuous beam in the rail model under several concentrated loads were set to simulate different stress conditions of the real rail, respectively. In order to evaluate the monitoring accuracy, one distributed optical fiber sensor and one fiber Bragg grating (FBG) sensor were installed on the lower surface of the rail model, the strain measured by FBG sensor and the strain calculated from FEA were taken as measurement references. The model test results show that the strain measured by distributed optical fiber sensor has a good agreement with those measured by FBG sensor and FEA. In the outdoor test, the real track suffered from displacement and temperature loads. The distributed optical fiber sensor installed on the rail can monitor the corresponding strain and temperature with a good accuracy.

• Journal of Communications and Networks
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• v.11 no.4
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• pp.350-358
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• 2009

In a wireless sensor network (WSN) setting, this paper presents a distributed decision-making framework and illustrates its application in an online structural health monitoring (SHM) system. The objective is to recover a damage severity vector, which identifies, localizes, and quantifies damages in a structure, via distributive and collaborative decision-making among wireless sensors. Observing the fact that damages are generally scarce in a structure, this paper develops a nonlinear 0-norm minimization formulation to recover the sparse damage severity vector, then relaxes it to a linear and distributively tractable one. An optimal algorithm based on the alternating direction method of multipliers (ADMM) and a heuristic distributed linear programming (DLP) algorithm are proposed to estimate the damage severity vector distributively. By limiting sensors to exchange information among neighboring sensors, the distributed decision-making algorithms reduce communication costs, thus alleviate the channel interference and prolong the network lifetime. Simulation results in monitoring a steel frame structure prove the effectiveness of the proposed algorithms.

• Structural Monitoring and Maintenance
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• v.1 no.2
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• pp.173-182
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• 2014

We describe the application of a distributed optical fiber sensor based on stimulated Brillouin scattering, as an integrated system for safety monitoring of railway infrastructures. The strain distribution was measured statically and dynamically along 60 meters of rail track, as well as along a 3-m stone arch bridge. We show that, gluing an optical fiber along the rail track, traffic monitoring can be performed in order to identify the train passage over the instrumented sector and determine its running conditions. Furthermore, dynamic and static strain measurements on a rail bridge are reported, aimed to detect potential structural defects. The results indicate that distributed sensing technology represents a valuable tool in railway traffic and safety monitoring.

• Journal of the Korean Society for Nondestructive Testing
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• v.25 no.6
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• pp.421-430
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• 2005

Brillouin time-domain analysis in optical fibres is a novel technique making possible a distributed measurement of temperature and strain over long distance and will deeply modify our view about monitoring large structures, such as dams, bridges, tunnels and pipelines, Optical fibre sensing will certainly be a decisive tool for securing dangerous installations and detecting environmental and industrial threats.

• Journal of Korea Multimedia Society
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• v.7 no.5
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• pp.755-765
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• 2004

Recently, the Internet-based distributed/parallel computing using many of idle hosts has been demonstrated its usefulness for processings of a large-scale task and involving several important issues. While executing a large-scale task, the realtime monitoring is required for adaptive strategy of the performance and state change of host. This paper provides the realtime monitoring and visualization on global computing infrastructure called PDP(Parallel Distributed Processing) which is a parallel computing framework implemented with Jana for parallel computing on the Internet.

• KIEE International Transactions on Power Engineering
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• v.4A no.4
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• pp.214-220
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• 2004

Power quality monitoring is the cornerstone for power quality analysis, diagnosis and improvement. The measurement of power quality (PQ) evolves from instantaneous metering to continuous monitoring. Furthermore, recent technologies enable us to construct more flexible, reliable, rapid and economical power quality monitoring system (PQMS). Therefore, this paper presents an improved PQMS with a new distributed monitoring structure. The proposed PQMS consists of a PQ meter, PQ analyzer and GUI. The PQ meter only collects raw data and the PQ analyzer performs power quality analysis. It has several advantages compared to conventional structures in economic efficiency, modularity, speed, etc. PQ monitoring algorithms to catch steady-state trends and to detect PQ events are also adapted to the proposed structure. Using the proposed structure and monitoring algorithm, a prototype PQMS is constructed and real-time testing is performed.

• Journal of Sensor Science and Technology
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• v.32 no.3
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• pp.199-206
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• 2023

This study presents a novel monitoring technique for underwater high-voltage direct current (HVDC) cables based on the Distributed Acoustic Sensor (DAS). The proposed technique utilizes vibration and acoustic signals generated on HVDC cables to monitor their condition and detect events such as earthquakes, shipments, tidal currents, and construction activities. To implement the monitoring system, a DAS based on phase-sensitive optical time-domain reflectometry (Φ-OTDR) system was designed, fabricated, and validated for performance. For the HVDC cable monitoring experiments, a testbed was constructed on land, mimicking the cable burial method and protective equipment used underwater. Defined various scenarios that could cause cable damage and conducted experiments accordingly. The developed DAS system achieved a maximum measurement distance of 50 km, a distance measurement interval of 2 m, and a measurement repetition rate of 1 kHz. Extensive experiments conducted on HVDC cables and protective facilities demonstrated the practical potential of the DAS system for monitoring underwater and underground areas.

• The KIPS Transactions:PartD
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• v.13D no.1 s.104
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• pp.139-146
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• 2006

This paper describes the design and implementation details of a distributed transactional workflow monitoring system. There have been prevalent research and development trends in the workflow literature - workflow systems tend to be completely distributed architectures to support very large-scale workflow applications on object-oriented and internet-based infrastructures. That is, the active (object), distributed (architecture), system-oriented (transaction), and large-scale (application) workflow systems are the key targets in terms of the research and development aspects. While the passive, centralized, human-oriented, and small/medium scale workflow systems are the typical instances of the traditional workflow systems. Unlike in the traditional (the client-server architecture) workflow systems, the workflow monitoring features should not be easily supported in the recent (the fully distributed architecture) workflow systems. At the same time, they need a set of additional monitoring features, such as gathering and displaying statistical (or overload status) information of the workflow architectural components dispersed on the internet. We, in this paper, introduce the additional workflow monitoring features that are necessarily required for the recent workflow systems, and show how to embed those features into a web-based distributed workflow system.