• Journal of the Korean Society for Aviation and Aeronautics
• /
• v.20 no.4
• /
• pp.14-20
• /
• 2012

A properly determined separation minima applied in Air Traffic Management(ATM) is critical for safe and efficient aircraft operations. The separation minima is primarily determined by the accuracy performance of surveillance system, and, due to the stringent aviation safety standard, the position accuracy of the surveillance system must be estimated with a high level of reliability. This study proposed a method for estimating the position accuracy of surveillance system with a relatively small amount of data by finding upper confidence limit instead of maximum likelihood values of unknown parameters. Through the proposed method, it is possible to determine a required separation minima with a more reliability in the face of data scarcity which often occurs when we implement a new surveillance system such as Automatic Dependent Surveillance-Broadcast (ADS-B).

• Transactions of the Korean Society of Machine Tool Engineers
• /
• v.13 no.4
• /
• pp.37-43
• /
• 2004

A measurement accuracy of theodolite system may be affected by a measurement environment, a measurement distance change and so on. This study was performed for measuring an accuracy when the height of scale bar is changed 0.05m, 0.5m, 1m and 1.5m under the distance 3m between two theodolites, the distance 4m from the theodolite system to scale bar and the distance 5m from the thodolite system to the horizontal target bar. And we could know that the best height is 0.05m and 1m.

• Korean Journal of Geomatics
• /
• v.3 no.1
• /
• pp.53-57
• /
• 2003

As the Korea Multi-Purpose Satellite-I (KOMPSAT-1) satellite can roll tilt up to $\pm$45$^{\circ}$, we have analyzed some KOMPSAT-1 EOC images taken at different tilt angles for this study. The required ground coordinates for bundle adjustment and geometric accuracy are obtained from the digital map produced by the National Geography Institution, at a scale of 1:5,000. Followings are the steps taken for the tilting angle of KOMPSAT-1 to be present in the evaluation of geometric accuracy of each different stereo image data: Firstly, as the tilting angle is different in each image, the characteristic of satellite dynamic must be determined by the sensor modeling. Then the best sensor modeling equation should be determined. The result of this research, the difference between the RMSE values of individual stereo images is mainly due to quality of image and ground coordinates instead of tilt angle. The bundle adjustment using three KOMPSAT-1 stereo pairs, first degree of polynomials for modeling the satellite position, were sufficient.

• Journal of Ocean Engineering and Technology
• /
• v.16 no.6
• /
• pp.37-43
• /
• 2002

The calculation of earthwork plays a major role in the plan or design phase of many civil engineering projects, such as seashore reclamation; and thus, it has become very important to improve upon its accuracy. There have been common drawbacks to earlier methods of ground profiling, such as dialing with sharp corners or the grid points of any tow straight lines. In this paper, we prepose an algorithm for finding a terrain surface using the natural boundary conditions and the both direction spline method, which interpolates the given three-dimensional data by using spline. As a result of this study, the algorithm of the proposed two methods to estimate pit excavation volume should provide a better accuracy than Spot height, Chambers, Chen, or Lin method. Also, the mathematical model mentioned offers maximum accuracy in estimating the volume of a pit excavation.

• Transactions of the Korean Society of Machine Tool Engineers
• /
• v.10 no.4
• /
• pp.97-103
• /
• 2001

The study on the high-speed machine tool is very important for the improvement of productivity since it can shortens cutting and non-cutting time. Especially, high speed of feed drive system is the major research field. In the industries of the advanced countries, the feed drive systems at the speed of 60 m/min have been already developed based on the high lead ball screws. In this study, a high speed feed drive system at the speed of 60 m/ min has been developed, and its movements characteris-tics are investigated. As the movement characteristics, positioning accuracy, angular accuracy, straightness and micro step-response are measured. Thermal characteristics of the system is also discussed. For measuring the movement characteris-tics, a laser interferometer, a memory-based Hi-coder and a cooling device are used. The experimental results confirm that the movement characteristics and the thermal behavior of the system are satisfactory in the aspect of accuracy and stability.

• Journal of the Korean Society of Manufacturing Technology Engineers
• /
• v.9 no.3
• /
• pp.143-149
• /
• 2000

Grinding technology in morden industry society is focusing on research and development for grinding stone and machin-ing parts for the purpose of high accuracy and high efficiency of products. But in order to equip the high technology and high accuracy of micro stone which is one of grinding stone a continuous effort on R& D is require. In this study the honing processing work of 2 cycle engine cylinder for motorcycle which has an open hole is carried out so as to investigate the boring and hone stone effects on accuracy of honing. As the experimental result of this study we could conclude that it is possible to secure good conditions of honing by controlling and keeping appropriate cycle-time in the stage of boring for the prior step of honing.

• Transactions of the Korean Society of Machine Tool Engineers
• /
• v.13 no.6
• /
• pp.81-86
• /
• 2004

Generally, automotive cylinder head is manufactured by FCD45 material that is hard to cutting materials, and it needs the accurate machining tool fir higher output of engine. This paper is concerned with a study on TiN coated 6 edges reamer for improving machining accuracy of cylinder head guide pin. The reamer shape is changed from 4 edges to 6 edges for the improvement of machining accuracy. Also, TiN coating is applied to the improvement of surface roughness of cylinder head guide pin and tool life of 6 edges reamer. It is noted that 6 edges reamer are effective in controlling the dimensional accuracy and surface roughness as well as increasing tool life.

• Journal of Korean Society for Geospatial Information Science
• /
• v.5 no.2 s.10
• /
• pp.111-119
• /
• 1997

The precise measurement and the construction of analysis system for human body is very important in human engineering fields. As this study is about to the accuracy improvement of digital image for human body monitoring, we apply the optimum exposure condition which is decided through the accuracy analysis of digital images those are acquired at the various exposure station to the human body model. We acquired digital data in 1mm accuracy and carried out various spatial analyses. We expect tile results of this study to offer the fundamental source data for the human engineering fields.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2002.10a
• /
• pp.1007-1010
• /
• 2002

The accuracy of high speed feeding type laser cutting M/C is the major factor directly concerned with the accuracy of the processed work, and the feed errors of feed system make the machining errors of work directly on processing. In this point, this study focused on the generative elements in feed errors of laser cutting M/C when operating its laser head. In order to improve the accuracy of this machining center, feed errors are measured by a laser interferometer.

• Journal of Korean Port Research
• /
• v.15 no.1
• /
• pp.75-85
• /
• 2001

Accuracy of dredging processes depends on the types of equipment used, the sediments encountered, whether the work to be performed is new or maintenance dredging, pre- and post-hydrographic surveying and so forth. Among those, position surveying accuracy which is directly determined by the control of the dredge's position and depth surveying accuracy being surveyed at the dredging point during dredging work are important factors. The purpose of this study is to develop 'Dredge Management System'for Grab dredge which is composed of 4 sub-system using LADGPS for dredge position determining system and dredging point determining system, tide gauge system and optical sensor for depth determining system and GIS and ENC for total management system. This system is installed on the grab dredge 'EUNJIN G-18'and applied to anchorage dredging work. at Pohang Harbor. The results revealed that this system is easy to operate, achieves good accuracy with only 45cm unevenness, reduces working period by 22 percent and saves cost 16.6 percent.