• Korean Journal of Applied Biomechanics
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• v.17 no.1
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• pp.129-134
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• 2007

The purpose of this study was to determine the variability of components of the vertical ground reaction force signal to seek the suitable number of attempt datum to be analyzed during running at 2m/s and 4m/s. For this study, six subjects (height mean:$174.5{\pm}4.4cm$, weight $671.5{\pm}116.4N.$, age:$25.0{\pm}yrs.$) were selected and asked to run at least 3 times each run condition randomly. FFT(fast Fourier transform) was used to analyze the frequency domain analysis of the vertical ground reaction forces signal and an accumulated PSD (power spectrum density) was calculated to reconstruct the certain signal. To examine the deviation of the vertical ground reaction between signals collected from an different number of attempt, variability of frequency, magnitude of passive peak, time up to the passive peak and maximum load rate were determined in a coefficient of variance. The variability analysis revealed that when analyze the vertical reaction force components at 2m/s speed running, which belongs to slow pace relatively, it would be good to calculate these components from signal of one attempt, but 4m/s speed running needs data collected from two attempts to decrease the deviation of signal between attempts. In summary, when analyzing the frequency and passive peak of the vertical reaction force signal during the fast run, it should be considered the number of attempt.

• Proceedings of the Korean Society of Coastal and Ocean Engineers Conference
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• 1996.10a
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• pp.124-128
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• 1996

인천항의 검조소의 검조기록은 우리나라의 수치측지기준(vertical geodetic datum)을 제공하는 중요한 자료이다. 본 연구에서는 최(1990)가 62년부터의 14년 자료를 처리, 발표한 것에 이어 83년에 다시 계속적인 분석을 보고하였지만 92년까지의 검조기록을 재분석하여 보고코저 한다. 분석에서 61년 이전의 자료는 하계의 DST(Daylight Saving Time)적용에 따른 자료가 보정되어 있지 못하므로 사용하지 않았으며 73, 74년 역시 검조소 이전에 따른 년자료의 연장이 완전하지 않아 취하지 않았다. (중략)

• Proceedings of the Korean Association of Geographic Inforamtion Studies Conference
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• 2010.06a
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• pp.272-273
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• 2010

본 연구에서는 NOAA에서 발간된 자료와 ICSM에서 발간한 자료를 토대로 조위관측의 정확도를 검토한 결과 최소 3개월, 또는 1년 이상의 장기관측을 하는 방안이 권장되며 NOS에서 공식적으로 인정된 19년 주기의 관측에 의한 국가기준(시기)을 정할 필요가 있음을 제시하고 있다.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.27 no.1
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• pp.713-722
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• 2009

Gravity measurement can determine the earth gravitational field, also is the fundamental to the research of earth gravitational field, geodesy and geodynamic, vertical movement of the crust, geoid surface, sea level and climate etc. Recently, National Geographic Information Institute (NGII) introduced FG-5 absolute gravity meter in order to lay a foundation for establishment of Absolute Gravity Network, and furthermore NGII plan to construct about 1,200 multi dimensional and function Unified Control Points(UCP) in nationwide. It will play an important role in development of high accuracy geoid model in South Korea. This paper explains the fundamental theory and method of relative gravity measurement, surveys the relative gravity of 21 stations using latest Scintrex CG-5 relative gravimeter. In addition, it calculates gravity values, compare and analysis gravity survey results using datum-free adjustment and weighted constraint adjustment. The results indicate show that datum-free and weighted constraint adjustment methods are available to determine high accuracy gravity achievement, datum-free method is more advantage than weighted constraint adjustment.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.25 no.5
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• pp.451-463
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• 2007

This paper describes issues of GPS network adjustment to determine coordinate sets of the $2^{nd}$ order national geodetic control points based on the Korean Geodetic Datum (KGD2002) which has been newly adopted in 2003, After outlining theoretical background of the GPS network processing, the adjustment procedure applied for this project is detailed. Throughout performing a series of minimally constrained adjustments, some outliers have been removed and magnitude of absolute and relative error for a stochastic modeling has been determined as 4mm+0.4ppm and 8mm+0.8ppm in the horizontal and vertical component, respectively. The over constrained adjustment by fixing the $1^{st}$ order control points was performed to derive final solution, indicating that the accuracy of the estimated coordinates was 2cm and 4cm in the horizontal and vertical component.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.27 no.2
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• pp.159-167
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• 2009

To obtain the gravity data with consistent quality and good distribution over Korea, to overcome the difficulties in constructing precision geoid from biased distribution of ground data, to resolve the discrepancy between the ground and ocean gravity data, an airborne gravity survey was conducted from Dec. 2008 to Jan. 2009. The data was measured at the average flying height of 3,000m and the data with cross-over error of 2.21mGal is obtained. The geoid constructed using this airborne gravity data shows the range of 9.34 $\sim$ 33.88m. Comparing the geoid with respect to the GPS/levelling data, a precision of 0.145m is obtained. After fitting, the degree of fit to GPS/levelling data was calculated about 5cm. It was found that there exists large biases in the area of south-western and northern part of the peninsular which is considered to be the effect of distorted vertical datum in Korea. Thus, more investigation on vertical datum would be needed in near future.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2007.04a
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• pp.81-84
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• 2007

This paper describes general procedure and results of the GPS 3rd odor network adjustment which has been carried out for determining coordinates sets with respect to new Korean Geodetic Datum, so-call Korean Geodetic Datum 2002 (KGD 2002). The adjustment begins with minimally constrained adjustments with respect to each of the 69 campaign networks. This was followed by constructing and adjusting sixteen block network. After detecting and removing outliers in the observation file, an attempt was made by applying the empirical stochastic modeling techniques used in the 2nd order network adjustment, so as to determine the magnitude of absolute and relative error for the estimated baseline vector from the GPS data processing. The over constrained adjustment were, in sequence, performed against each of the block network. In this adjustment, both of the 2nd order control points in the block network and the 3rd order control points overlapped with adjacent network whose coordinates were already determined from a preceding adjustment. The final adjustment results have shown that the accuracy of the 3rd order network adjustment was better than 1cm and 2cm in horizontal and vertical component, respectively.

• IE interfaces
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• v.6 no.1
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• pp.31-45
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• 1993

Setup planning for machining processes is a part of fixture planning which is also a part of process planning. A setup of a part is defined as a group of features which are machined while the part is fixtured in one single fixture. Setup planning includes a number of tasks such as the selection of setup, sequence of setups and datum frame for each setup. Setup planning is an important function in fixture planning which must be able to support and to clamp a workpiece to prevent deflections caused by machining and clamping loads. This paper presents setup planning system using expert system approach(SPES) for prismatic parts which can be machined on vertical milling machine. SPES consists of preprocessing module and main processing module. Preprocessing module executes the conversion of feature data to frame type data and the determination of setups, and main processing module executes the determination of datum frame of each setup and sequance of setups. Preprocessing module is coded by C language and main processing module is a rule-based expert system using EXSYS pro. The performance of SPES is evaluated through case studies and the results show successful work except for operation sequence of machining holes. This is due to the limited rules for machining holes.

• Journal of the Korea institute for structural maintenance and inspection
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• v.12 no.5
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• pp.116-124
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• 2008

In order to evaluate the behavior patterns of the ring beam by excavation at the vertical wall with circular section, the measured field datum were analyzed and evaluated in this study. Additionally, stress patterns of the ring beam with the change of excavation depth were estimated by using FE analysis. As the results, it was shown that the tendency of the measured values for the behavior patterns of the ring beam is similar to the analyzed values in FE analysis. From the tendency, it was confirmed that the behaviors of the ring beam due to change of excavation depth can predict by FE analysis using the suggested method in this study.

• Journal of Sasang Constitution and Immune Medicine
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• v.18 no.2
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• pp.41-49
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• 2006

1. Objectives The Face is an important standard for the classification of Sasang Contitutions. We are developing 3D Face Automatic Recognition Apparatus to analyse the facial characteristics. So We should examine a shape demobilization error of 3D Face Automatic Recognition Apparatus. 2. Methods We compared facial shape data be demobilized by 3D Face Automatic Recognition Apparatus with facial shape data that be demobilized by 3D laser scanner. The subject was two korean men. And We analysed the average error and the maximum error of two data. In this process, We used one datum point(the peak of nose) and two datum line(vertical section and horizontal section). 3. Results and Conclusions In each this comparison, the average error of vertical section was 1.962574mm and 2.703814mm. and the maximum error of vertical section was 16.968249mm and 18.61464mm. the average error of horizontal section was 4.173203mm and 21.487479mm. and the maximum error of horizontal section was 3.571210mm and 17.13255mm. Also We complemented this apparatus a little and We reexamined a shape demobilization error of 3D Face Automatic Recognition Apparatus again. Accuracy of a shape demobilization was improved a little. From now on We complement accuracy of a shape demobilization in 3D Face Recognition Apparatus.