• Proceedings of the Korean Institute Of Construction Engineering and Management
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• autumn
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• pp.395-400
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• 2001

In construction projects, it is very important to evaluate the performance of works in comparison with the cost and schedule plans. So, on the first of July, 2000, the Ministry of Construction and Transportation announced the EVMS will be applied in public sector soon. However there are still many arguments about how to establish the Performance Measurement Baseline(PMB) and how to evaluate the progress with accuracy. And many people confuse the meaning of EVMS with that of cost and schedule management. So, the purpose of this research is to propose the new useful methods to set up the PMB and to assess the exact progress in consideration of cost, schedule, and float time for successful implementation of EVMS.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2008.11a
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• pp.513-516
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• 2008

The risk in the constructions projects is extremely diverse because there are too many indefinite factors. Therefore, Performance Measurement Baseline(PMB) is needed regularly during the construction process. However, nowdays, the PMB in the constructions projects is for contractors' PMB and Performance Management(PM). Clients have a lot of difficulties to control and manage the projects. Therefore, this paper classifies schedule and cost data of the public apartments houses which is a actual cases into types and then conducts regression analysis and deduces a regression. In addition to this paper establishes the Work Breakdown Structure(WBS) and suggests the PMB for the clients through using that.

• International Journal of Control, Automation, and Systems
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• v.4 no.3
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• pp.333-343
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• 2006

In this paper, the baseline-length information is directly modeled as a measurement for the Wald test, which speeds up the resolution convergence of the integer ambiguity of GPS carrier phase measurements. The convergent speed improvement is demonstrated using numerical simulation and real experiments. It is also shown that the integer ambiguities can be resolved using only four actual satellite measurements with very reasonable convergence speed, if the baseline-length information is used just like one additional observable satellite measurement. Finally, it is shown that the improvement of convergence speed of the Wald test is due to the increase of the probability ratio with the use of the baseline-length constraint.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.11 no.5
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• pp.108-122
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• 2001

As bridge design is advancing toward the performance-based design. it becomes increasingly important to monitor and re-evaluate the long-term structural performance of bridges. Such information is essential in developing performance criteria for design. In this research. sensor systems for long-term structural performance monitoring have been installed on two highway bridges. Pre1iminary vibration measurement and data analysis have been performed on these instrumented bridges. On one bridge, ambient vibration data have been collected. based on which natural frequencies and mode shapes have been extracted using various methods and compared with those obtained by the preliminary finite element analysis. On the other bridge, braking and bumping vibration tests have been carried out using a water truck In addition to ambient vibration tests. Natural frequencies and mode shapes have been derived and the results by the breaking and bumping vibration tests have been compared. For the development of a three dimensional baseline finite element model, the new methodology using a neural network is proposed. The proposed one have been verified and applied to develop the baseline model of the bridge.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.42 no.6
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• pp.453-460
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• 2014

We analyze fault detection algorithm of ephemeris included in navigation message, which is one of the GNSS risk factors. This algorithm uses carrier-phase measurement and baseline vector of two reference stations and is alternative method for uncertainty condition of previous ephemeris. Even though same ephemeris fault is occurred, the geometry condition, between baseline vector of reference stations and satellites, effects on performance of algorithm. Also, we introduce the suitable geometry of reference stations, threshold and performance index (MDE : Minimum Detectable Error) in jeju international airport.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• v.2
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• pp.23-26
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• 2006

Modernized GPS will have three frequencies modulated with three signals, which will be accessible to all users in the near future. This new frequency provides an opportunity to resolve the double differenced (DD) integer ambiguity very fast and with almost no baseline constraints. In order to study the performance of triple frequency system for Ambiguity Resolution (AR) over the medium baseline under different ionospheric levels, the Klobuchar Model was implemented and used in our triple simulation to generate the ionospheric delay. Furthermore, the White-Gaussian noise applying to distance-dependent parameters was added to the DD ionospheric delay. For medium baseline (defined as here 20 to 40kms), success rates of AR has been pretty improved. In this paper, the medium baseline AR strategies that take advantage of carrier phase measurement on the third frequency will be discussed.

• Journal of Positioning, Navigation, and Timing
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• v.10 no.3
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• pp.159-168
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• 2021

Precise Point Positioning-Real Time Kinematic (PPP-RTK) is an improved PPP method that provides the user receiver with satellite code and phase bias correction information in addition to the satellite orbit and clock, thus enabling single-receiver ambiguity resolution. Single station PPP-RTK concept is special case of PPP-RTK in that corrections are computed, instead of a network, by only one single GNSS receiver. This study is performed to experimentally verify the positioning accuracy performance of single baseline RTK level by a user who utilizes correction for a single station PPP-RTK using dual frequencies. As an experimental result, the horizontal and vertical 95% accuracy was 2.2 cm, 4.4 cm, respectively, which verify the same performance as the single baseline RTK.

• Journal of the Korea Institute of Military Science and Technology
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• v.9 no.2 s.25
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• pp.60-69
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• 2006

The PMB(performance measurement baseline) is the total time-phased budget plan against which program performance is measured. Additionally it is the schedule for expenditure of the resources allocated to accomplish program scope and schedule objectives, and is formed by the budget assigned. In this paper, we suggest an improvement of the R & D(research and development) program for defense acquisition by using the PMB and an application of the IBR(integrated baseline review) to review the PMB for project manager of the defense agency.

• Journal of Institute of Control, Robotics and Systems
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• v.19 no.8
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• pp.702-708
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• 2013

Underwater TRN (Underwater Terrain Referenced Navigation) estimates an underwater vehicle state by measuring a distance between the vehicle and undersea terrain, and comparing it with the known terrain database. TRN belongs to absolute navigation methods, which are used to compensate a drift error of dead reckoning measurements such as IMU (Inertial Measurement Unit) or DVL (Doppler Velocity Log). However, underwater TRN is different to other absolute methods such as USBL (Ultra-Short Baseline) and LBL (Long Baseline), because TRN is independent of the external environment. As a magnetic-field-based navigation, TRN is a kind of geophysical navigation. This paper develops an EKF (Extended Kalman Filter) formulation for underwater TRN. A filter propagation part is composed by an inertial navigation system, and a filter update is executed with echo-sounder measurement. For large-initial-error cases, an adaptive EKF approach is also presented, to keep the filter be stable. At the end, simulation studies are given to verify the performance of the proposed TRN filter. With simplified sensor and terrain database models, the simulation results show that the underwater TRN could support conventional underwater navigation methods.

• Journal of Institute of Control, Robotics and Systems
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• v.11 no.7
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• pp.621-626
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• 2005

With precise GPS carrier positioning result, we can get attitude information if GPS antenna has adequate attaching position on the vehicle. In this case, baseline length information can be bandied as an additional measurement or constraint. In this paper, we have proposed a method to improve the attitude accuracy. To overcome nonlinearity of baseline observation model, we analyze attitude estimation result using existing estimation method like a least square method and Kalman filter, and apply a new nonlinear estimation method an unscented Kalman filter Finally we confirm the improvement of attitude estimation result in the case of appling the unscented Kalman filter.