• Journal of Electrical Engineering and Technology
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• v.7 no.2
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• pp.141-150
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• 2012

The present study examines an efficient congestion management system compatible with the evolving environment. The key is to build an information model shared and exchanged for marketbased solutions to alleviate congestion. Traditional methods for congestion management can be classified into two categories, i.e., the centralized scheme and the decentralized scheme, depending on the extent to which the independent system operator (ISO) is involved in market participants' (MPs) activities. Although the centralized scheme is more appropriate for providing reliable system operation and relieving congestion in near real-time, the decentralized scheme is preferred for supporting efficient market operation. The minimum set of information between the ISO and MPs for decentralized scheme is identified: i) congestion-based zone, ii) Power Transfer Distribution Factors, and iii) transmission congestion cost. The mathematical modeling of the proposed information is expressed, considering its process of making effective use of information. Numerical analysis is conducted to demonstrate both cost minimization from the MP perspective and the reliability enhancement from the ISO perspective based on the proposed information exchange scheme.

• Journal of the Korean Society of Safety
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• v.19 no.1
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• pp.23-30
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• 2004

Modern production systems are very complex by request of automation, and failure modes that occur in thisautomatic system are very various and complex. The efficient fault diagnosis for these complex systems is essential for productivity loss prevention and cost saving. Traditional fault diagnostic system which perforns sequential fault diagnosis can cause catastrophic failure during diagnosis when fault propagation is very fast. This paper describes the Real-time Intelligent Multiple Fault Diagnosis System (RIMFDS). RIMFDS assesses current machine condition by using sensor signals. This system deals with multiple fault diagnosis, comprising of two main parts. One is a personal computer for remote signal generation and transmission and the other is a host system for multiple fault diagnosis. The signal generator generates various faulty signals and image information and sends them to the host. The host has various modules and agents for efficient multiple fault diagnosis. A SUN workstation is used as a host for multiple fault modules and agents for efficient multiple fault diagnosis. A SUN workstation is used as a host for multiple fault diagnosis and graphic representation of the results. RIMFDS diagnoses multiple faults with fast fault propagation and complex physical phenomenon. The new system based on multiprocessing diagnoses by using Hierarchical Artificial Neural Network (HANN).

• The Transactions of the Korea Information Processing Society
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• v.7 no.11S
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• pp.3675-3683
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• 2000

The Handoff is the core technical factor that is required when mobile host moves from one area to another, while transmitting and receiving data. The existing works try to minimize the loss of pockets by forwarding packets to the Cell which a mobile host will move to. However, though the loss quantity is little, the accumulated loss can del(rade the performance of the TCP, and can be a serious problem if data is sensitive to the loss of packets. In this paper, we can reduce a memory requesting in FA by restricting the mobile host to move within at most 2 movable cells and design the improved handoff protocol for Mil to receive packets seamlessly in spite of handoff. We can evaluate that the suggested method is superior to the previous method, as a result of comparing with it.

• Proceedings of the KSRS Conference
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• 2002.10a
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• pp.235-240
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• 2002

This paper shows the desist concept of an ATS(Antenna Tracking Software) to control the movement of the MSC(Multi-Spectral Camera) antenna. The MSC has a two-axes directional X-band antenna for image transmission to KGS(KOMSAT2 Ground Station). The main objective of the ATS is to drive the APM(Antenna Pointing Mechanism) to the required elevation and the azimuth position according to an appropriate TPF(Tracking Parameter File). The ATS is implemented as one task of the SBC(Single Board Computer) software, which uses VxWorks as a real time OS. The ATS has several operational modes such as STANDBY mode, First EL mode, First AZ mode, Normal Operation mode, and so on. The ATS uses two PI controllers fur the velocity and the position loop respectively, to satisfy the requirements specification. In order to show the feasibility of the described design concept, the various simulations and the experiments are performed under specific test configuration.

• Journal of Korean Society of Water and Wastewater
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• v.31 no.3
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• pp.249-256
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• 2017

Recently, application areas based on M2M (Machine-to-Machine communications) and IoT (Internet of Things) technologies are expanding rapidly. Accordingly, water flow and water quality management improvements are being pursued by applying this technology to water and sewage facilities. Especially, water management will collect and store accurate data based on various ICT technologies, and then will expand its service range to remote meter-reading service using smart metering system. For this, the error in flow rate data transmitting should be minimized to obtain credibility on related additional service system such as real time water flow rate analysis and billing. In this study, we have identified the structural problems in transmitting process and protocol to minimize errors in flow rate data transmission and its handling process which is essential to water supply pipeline management. The result confirmed that data acquisition via communication system is better than via analogue current values and pulse, and for communication method case, applying the industrial standard protocol is better for minimizing errors during data acquisition versus applying user assigned method.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.26 no.2
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• pp.177-183
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• 2002

The field tests on the waterhammer were carried out in the pump pipeline system with an air chamber. The effects of the input variables and the design parameters for the air chamber were investigated by both the numerical calculations and the experiments. Because the waterhammer problems as a result of the pump power failure were the most important, these situations were carefully studied. Among the input variables used in the waterhammer analysis, the polytropic exponent, the discharge coefficient and the wavespeed had influence on the simulated results in that order, and were calibrated in comparison with the experimental results. As the initial air volume in a vessel increased, the period of waterhammer increased and the pressure variation decreased, resulting from the reduction of the rate of pressure change in the air chamber. Using smaller orifice in the bypass pipe, the pressure rise was suppressed in some degree and the pressure surge was dissipated more rapidly as time passed. The simulations were in fairly good agreement with the measured values until 1∼2 periods of waterhammer. Not only the maximum and minimum pressures in the pipe1ine but also those occurring times were reasonably predicted. The computer program developed in this study will be useful in designing the optimum parameters of an air chamber for the real pump pipeline system.

• Journal of KIISE:Computing Practices and Letters
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• v.6 no.1
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• pp.36-44
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• 2000

In this paper, we describe the developing of a tool which supports both multimedia presentation with user's participation through a high speed network and authoring of various media using a single authoring tool. To support real-time synchronous multimedia presentation, we adopt dynamic synchronization method and adaptive transmission algorithm for synchronizing data transfer rate between sender and receiver using buffer management algorithm based on QoS parameters. And we also allow user's participation in the presentation using TRSG(Temporal Relationship Specification Graph) model. Finally, the proposed tool supports the minimal level of QoS and its continuous play-out using event auditing threads which control the current state of a multimedia presentation continuously by monitoring of negative factors effecting on QoS, and synchronization.

• Journal of Korean Medical Science
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• v.33 no.53
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• pp.348.1-348.6
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• 2018

We report a case of Middle East respiratory syndrome coronavirus (MERS-CoV) infection in a 61-year-old businessman returning from Kuwait. The patient arrived there on August 16, 2018, developed watery diarrhea on August 28 (day 0), and came back to Korea on September 7 (day 10) as his condition worsened. Upon arrival, he complained of diarrhea and weakness, but denied any respiratory symptoms, and he directly went to visit an emergency room. Chest radiography revealed interstitial infiltrates in the lungs, and he was immediately transferred to an isolation unit. Quantitative real-time PCR analysis of sputum samples taken on day 11 returned positive for MERS-CoV. No secondary MERS-CoV infection was identified among people who had close contact with him. This case underscores the importance of a high index of suspicion of MERS-CoV infection in any febrile patients who present after a trip to the Middle East.

• The Journal of the Korea institute of electronic communication sciences
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• v.14 no.5
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• pp.991-1000
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• 2019

The flying-disc game has started since 1940. It has been spreading rapidly in Korea since 2007, mainly in elementary schools. Additionally, as sports science has been developed, research on flying discs has been continued to build a monitoring system for technological improvement and efficiency. In this paper, we acquire information on the user's flying-disc using 9-axis motion sensor and GPS. Then we propose a method for wireless transmission using Bluetooth 5.0. Specifically, the HW platform was designed and implemented not only to monitor a real-time data but also to compare and analyze rotational speed, flight trajectory, and a count of disc rotation through post-processing.

• Smart Structures and Systems
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• v.5 no.6
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• pp.663-679
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• 2009

The use of Micro-Electro-Mechanical Systems (MEMS) accelerometers in geotechnical instrumentation is relatively new but on the rise. This paper describes a new MEMS-based system for in situ deformation and vibration monitoring. The system has been developed in an effort to combine recent advances in the miniaturization of sensors and electronics with an established wireless infrastructure for on-line geotechnical monitoring. The concept is based on triaxial MEMS accelerometer measurements of static acceleration (angles relative to gravity) and dynamic accelerations. The dynamic acceleration sensitivity range provides signals proportional to vibration during earthquakes or construction activities. This MEMS-based in-place inclinometer system utilizes the measurements to obtain three-dimensional (3D) ground acceleration and permanent deformation profiles up to a depth of one hundred meters. Each sensor array or group of arrays can be connected to a wireless earth station to enable real-time monitoring as well as remote sensor configuration. This paper provides a technical assessment of MEMS-based in-place inclinometer systems for geotechnical instrumentation applications by reviewing the sensor characteristics and providing small- and full-scale laboratory calibration tests. A description and validation of recorded field data from an instrumented unstable slope in California is also presented.