• Proceedings of the KIEE Conference
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• 2000.07a
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• pp.85-87
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• 2000

In real-time power system control, it is essential to measure the power system variables which are voltage. current, real and reactive power, power factor, system frequency and etc. this variables can be estimated or calculated by the synchronized phasor informations of voltage and current. Therefore, the synchronized phasor measurement of voltage and current is very important to real-time power system control. So, we develop SPMD(Synchronized Phasor Measurement Device) for synchronized phasor measurement of voltage and current. In this paper, we present the design and implementation of SPMD for real-time phasor measurement and prove its performance by the test results.

• Proceedings of the Korean Geotechical Society Conference
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• 2009.03a
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• pp.1139-1146
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• 2009

Collapse of cut slope includes many uncertainties in view of the reason and time. So, in the past, risky cut slopes have been dealt after they've been collapsed through post-management measures. But recently, advanced disaster prevention system is required, and as a part of that RTMS(Real-Time Monitoring System) was developed. In this study, stability of risky cut slope was evaluated by site investigation. To grasp deformation behavior characteristics of slope, numerical analysis based on FEM was performed and using results of that, specific standards for installation of Real-Time Monitoring System were suggested.

• Journal of Environmental Science International
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• v.17 no.2
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• pp.257-267
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• 2008

Groundwater recharge characteristics in a fractured granite area, Mt. Geumjeong, Korea. was interpreted using bedrock groundwater and wet-land water data. Time series analysis using autocorreclation, cross-correlation and spectral density was conducted for characterizing water level variation and recharge rate in low water and high water seasons. Autocorrelation analysis using water levels resulted in short delay time with weak linearity and memory. Cross-correlation function from cross-correlation analysis was lower in the low water season than the high water season for the bedrock groundwater. The result of water level decline analysis identified groundwater recharge rate of about 11% in the study area.

• Proceedings of the KSRS Conference
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• 2005.10a
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• pp.597-600
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• 2005

The software streaming technology enables telematics software to be automatically updated through a wireless network. When the software starts running, software streaming system inspects its version and then, automatically download latest one. The software streaming system breaks the software into several pieces that are streamed to the user as needed. In this way, software streaming system can improves the telematics application load time while updating the software through wireless network. In our experiments, the application load time was reduced about 7 times compared to downloading whole software at best case.

• Journal of the Korean Institute of Telematics and Electronics D
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• v.34D no.5
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• pp.52-60
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• 1997

Photonic switching systems with throughput above Tbit/s are reuried to transport vast amounts of information for the coming B-ISDN. In this paper, we proposed a new time-division hybrid WDM photonic swithc architecture, the proposed basic switch module has simple configuratin consisted of frequency routers for wavelength division and cell coders and star couplers for time division. Through the comparison with other sysems in field of switching capacity, hardware complexity and cost effect of implemetnation, we proved that the proposed system is suitable for large-capacity photonic switching system.

• Korean Journal of Remote Sensing
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• v.18 no.3
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• pp.147-153
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• 2002

The real-time reception and recording of down-link mission data from a satellite requires the highest reliability because the data lost in receiving process cannot be recovered. The data receiving and recording system has moved from a set of dedicated hardware and software components to commercial-off-the-shelf (COTS) components in order to reduce the system cost as well as to upgrade the system easily for handling other satellite data. The use of COTS hardware and middleware components prevents the system developer from correcting or modifying the internal operations of the COTS components, and hence, instant performance degradation of the COTS components which affects the reliable data acquisition must be covered by a software algorithm. This paper introduces the instant performance problem of a COTS data recording device which leads to the data loss in the real-time data reception and recording process. As a result, the requirement of the modification of the conventional data read/write technique is issued. In order to overcome the data loss problem due to the use of COTS components and the conventional software technique, a new algorithm called a software buffering technique is proposed. The experiments show that the application of the proposed technique results in reliable real-time reception and recording of high speed serial data.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.37 no.2
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• pp.55-61
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• 2014

Recently, the manufacturing system is being changed in a mass customization and small quantity batch production. MES is a powerful production management tool supporting production optimization from the process initiation to the final shipment. It is a production management system which plans and executes based on the production data in the shop floor. This study deployed the utilization of production data and web HMI system to process real-time production data through the collection with the shop floor. The developed system was applied to the equipment operating time and other production data could be processed with the real-time. The proposed system and web HMI can be applied for various production systems by using different logic.

• Ocean and Polar Research
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• v.40 no.3
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• pp.99-114
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• 2018

In the present study, we assess the GloSea5 (Global Seasonal Forecasting System version 5) near-surface ocean current forecasts using globally observed surface drifter dataset. Annual mean surface current fields at 0-day forecast lead time are quite consistent with drifter-derived velocity fields, and low values of root mean square (RMS) errors distributes in global oceans, except for regions of high variability, such as the Antarctic Circumpolar Current, Kuroshio, and Gulf Stream. Moreover a comparison with the global high-resolution forecasting system, HYCOM (Hybrid Coordinate Ocean Model), signifies that GloSea5 performs well in terms of short-range surface-current forecasts. Predictions from 0-day to 4-week lead time are also validated for the global ocean and regions covering the main ocean basins. In general, the Indian Ocean and tropical regions yield relatively high RMS errors against all forecast lead times, whilst the Pacific and Atlantic Oceans show low values. RMS errors against forecast lead time ranging from 0-day to 4-week reveal the largest increase rate between 0-day and 1-week lead time in all regions. Correlation against forecast lead time also reveals similar results. In addition, a strong westward bias of about $0.2m\;s^{-1}$ is found along the Equator in the western Pacific on the initial forecast day, and it extends toward the Equator of the eastern Pacific as the lead time increases.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.510-513
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• 2005

Due to the asymptotic property, deadbeat control can hardly be applied to the continuous time system control. But some delay element method can deal such a problem. Besides delay element method, well-known digital deadbeat control can be used by the aid of some smoothing elements. In this paper, 2nd order smoothing element is used for the smoothing of the digital deadbeat controller. And this element is argumented to the plant, and so control problem is to control the argumented system digitally. We simulated this control system using Matlab language and finally apply this algorithm to the rotary inverted pendulum system.

• ETRI Journal
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• v.26 no.2
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• pp.149-160
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• 2004

In this paper, we present an interactive data broadcasting system compliant with the Advanced Television Systems Committee (ATSC) standards. The proposed system provides users not only with various data broadcasting services but also remote interactive services. For various data broadcasting services, we have adopted a synchronized data injector that calculates the transmission time of synchronized data accurately and multiplexes synchronized data with the data of an MPEG-2 audio-visual program according to the calculated transmission time. To support remote interactive services, we designed and implemented a return channel server connected on a bi-directional interaction channel. Test results show that the proposed system provides both an asynchronous and synchronized data broadcasting service and remote interactive service appropriately.