• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2002.04a
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• pp.77-84
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• 2002

The Global Positioning System, GPS technology has been widely used in positioning and attitude determination. It is well known that the accuracy, availability and reliability of the positioning results are heavily dependent on the number and geometric distribution of tracked GPS satellites. Because of this limitation, in some situations, such as in urban canyons, underground space or inside of buildings, it is really hard to navigate with GPS receiver. Therefore, in order to improve the performance of satellite-based positioning, the integration of GPS with the pseudolite technology has been proposed. With this pseudolite technology, it is expected that seamless positioning service can be provided in wider area without replacing existing GPS receivers. On the other hand, to adopt pseudolites at larger scale, it is necessary to verify how the pseudolites can complement the existing GPS-based positioning. In this paper the authors present the detail of experimental investigations and the results of the fundamental verification for seamless positioning using integration of GPS and pseudolite. This paper shows that the accuracy and efficiency of integrating GPS and pseudolite through the dynamic and static positioning experiment and discuss about the influence on GPS receiver by pseudolite signal. The experimental results indicate that the accuracy of the height component can indeed be significantly improved, to approximately the same level as the horizontal component.

• Proceedings of the Korean Geotechical Society Conference
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• 2006.03a
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• pp.362-371
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• 2006

The behaviour characteristics of Granular Compaction Pile(GCP) are mainly governed by the lateral confining pressure mobilized in the matrix soft soil to restrain the bulging failure of the granular compaction pile. The GCP method is most effective in soft soil with untrained shear strength ranging from $15\sim50\;kPa$. However, the efficiency of this method is falling down in the more compressible soil conditions, which does not provide sufficient lateral confinement. In the present study, the GCP method reinforced with uniformly graded permissible concrete is suggested for the extension of application to the soft ground. Also, large triaxial compression tests are conducted on composite- reinforced soil samples for verification of availability of the suggested method and the settlement estimation method of the reinforced GCP is proposed. Further, for the verification of a validity of the proposed method, predicted settlements are compared with results of numerical analyses. Tn addition, parametric studies are performed together with detailed analyses of relevant design parameters.

• Journal of Navigation and Port Research
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• v.45 no.5
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• pp.231-237
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• 2021

Enhancing the performance of maritime wireless communication has been highlighted by the issue of cell planning in the sea area because of lack of an appropriate Propagation Loss Model (PLM). To resolve the cell planning issue in vast sea areas, it was essential to develop the (PLM) matching the intended sea area. However, there were considerable gaps between the prediction of legacy PLMs and field measurement in propagation loss and there was a need to develop the adjusted PLM (A-PLM). Therefore, cell planning was performed on this adjusted model, including modification of the base station's location, altitude, and antenna azimuth to meet the quality objectives. Furthermore, in order to verify the availability of the cell planning, Communication Service Quality Monitoring System (CS-QMS) was developed in the LTE-Maritime project to collect LTE signal quality information from the onboard equipment at regular intervals and to ensure that the service quality was high enough to satisfy the goals in each designated grid. As a result of verification, the success rate of RSRP was 95.7% for the intensive management zone (IMZ) and 96.4% for the interested zone (IZ), respectively.

• Journal of Wind Energy
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• v.15 no.1
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• pp.50-59
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• 2024

Floating LiDAR systems provide significant savings in cost and time compared to the fixed meteorological mast measurement type, and have the advantage of being able to be deployed in various locations due to less restriction on the depth of the installation site. However, to use the wind data collected by a floating LiDAR system commercially, verification procedure is required to ensure that the collected data have sufficient availability. The Carbon Trust OWA roadmap presents guidelines in three stages for the reliability of the wind data collected using a floating LiDAR system. Companies developing wind farms are requesting at least Stage 2 (pre-commercial stage) presented by OWA, and many overseas companies are leading the domestic and overseas markets. In this paper, we introduce the case of OWA Stage 2 certification for the commercial operation of floating LiDAR systems.

• The Journal of the Korea Contents Association
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• v.15 no.12
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• pp.1-7
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• 2015

These anti-jamming GPS systems are verified using large anechoic chamber or field-test until now. When using a large anechoic chamber, Independent verification from external enviroments like noise is an advantage but high cost and availability of chamber are disadvantages. And in case of field test, verification under real propagation enviroment is an advantage but security problem of military equipments and problem of making same test condition are disadvantages. This paper presents an newly developed anti-jamming GPS test system. This test system mainly consists of small anechoic chamber, jamming divider, jamming signal generator and satellite simulator. The small anechoic chamber is installed many jamming antennas to transmit multi jamming signals and the jamming divider is newly developed to control multi jamming signals. According to self performance test and combined test with Anti-jamming GPS receiver, we verified our system's reliability.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.54 no.1
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• pp.27-32
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• 2005

This study presents an analysis technique that can consider all variables which are needed in the design of short circuit current capability of electrical contacts. Required variables in the design are material of contact, contacting area, applied force, asperity of surface, current and so on. Short circuit current capability test was carried out for the interrelation of design variables and the verification of analysis technique. Temperature rise equation of the contacts was obtained from the test results, and also, a standard that is criterion of the occurrence availability of melting or spot of contact surface from test results was established.

• Journal of the Korean housing association
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• v.16 no.5
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• pp.83-90
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• 2005

This study aimed to examine the possibility of remodeled nursing home utilizing a closed school in Kunsan, where the number of closed schools increases and the ratio of elderly population grows. Major contents of research were understanding architectural characteristics of closed school and elderly housing in the sample area, and a suggestion of remodeling a closed school into nursing home. Conclusions can be summarized as follows; understanding the high ratio of elderly population and increases of closed schools in sample area, verification of overall possibility in remodeling a closed school into elderly facility, confirmation of availability in changing regular class room to residential rooms, and some proposals of principal points in floor planning - homelike atmosphere by small scaled residential units(10 persons), spatial hierarchy for residents' mental comfort, sliding door for accessibility, kitchen and dining space in residential unit for the residents' participation in houseworks.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.63 no.4
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• pp.226-235
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• 2014

Nowadays, railroads are considered the most efficient form of mass transportation. Furthermore, it is necessary that railroads be paired with state-of-the-art safety equipment. Unfortunately, it is impossible to prevent 100% of accidents that may be caused by system or human errors. In order to prevent future accidents, RAMS activity and Functional Safety Certification are required for new systems that are under development. In this paper we evaluate the necessity of the application of RAMS and the performance of RAMS in the system development process. We also explore the Safety Evaluation Procedure required for RAMS certification.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.11a
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• pp.223-226
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• 2005

In previous research, we proposed robust saturation controller which involves both actuator's saturation and structured real parameter uncertainties. This controller can analytically prescribed the upper and lower bounds of parameter uncertainties, and guarantee the closed-loop robust stability of the system in the presence of actuator's saturation. And the availability and the effectiveness of the proposed robust saturation controller were verified through numerical simulations. In this paper, we verify the robust stability of this controller through experimental tests. Especially, we show unstable cases of other controllers in comparison with this controller. Experimental tests are carried out in the laboratory using a two-story test structure with a hydraulic-type active mass damper.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 1994.04a
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• pp.29-37
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• 1994

It is reported that north Korea has already developed 1,500 to 2,000-km-range Scud missile. As a defensive strategy against Scud attack on military and civilian facilities the military authorities are considering deployment of Patriot missile. This paper deals with its optimal deployment strategy. In this problem a Patriot missile which has multiple-facility responsibility may be able to protect each of its assigned facilities only with a certain probability, not absolute protection, and it may not be adequate to have only a single missile protect a facility, either because of its operational reliability or because of its limited availability at any given point in time. We formulate this problem into the probabilistic partial set covering model developed by Sherali and Kim. The applicability, verification and validation of the model are tested via an abbreviated case study.