• 생태와환경
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• 제43권2호
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• pp.338-344
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• 2010

상수원 및 수계의 수질관리 업무를 효율적이고 능동적으로 수행하고, 수질오염사고 발생시 신속한 대응조치를 할 수 있는 조기경보체계 구축을 위하여 주요 상수원 및 하천 등에 수질자동측정망을 설치하여 운영하고 있다. 수온, pH, EC, DO, TOC 항목에 대한 정도평가를 실시하여, 수질자동 측정 자료에 대한 정확도를 확보하여 신뢰도를 제고하고자 하였다. 수질자동측정기기와 수동측정기기에 대한 측정값을 비교한 결과, 대체로 일반항목(수온, pH, EC, DO) 및 TOC의 상대정확도가 20% 이내의 목표를 만족하였다. 그러나 수질자동측정소의 저류수조의 측정기기(내부)와 채수지점의 측정기기(외부)의 측정값 차이를 분석한 결과, 채수거리가 먼 측정소의 DO에 대한 내부-외부의 상대정확도는 목표값을 다소 벗어나는 것으로 나타났다. 채수관로에 조류 및 미생물 부착에 의한 오염이 원인으로 판단되어 역세척하여 측정한 결과, 측정된 DO 농도는 최대 53%까지 상승하는 효과를 나타냈다. 따라서 채수관로 관리가 수질자동측정 자료의 신뢰성을 확보하는데 중요함을 알 수 있었다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2002년도 춘계학술대회 논문집
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• pp.719-722
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• 2002

Cylindrical cam mechanisms are used commonly in many automatic machinery. But the cylindrical cam is very difficult to design and manufacture the shape. The motion analysis of the cylindrical cam can check the accuracy between designed data and manufactured data of the cam shape and can reproduce without the cam design data. The motion analysis of the cylindrical cam consists of displacement analysis, velocity analysis and acceleration analysis. This paper performs the motion analysis of a cylindrical cam with translating follower by using a relative velocity method and a central difference method. The displacement is calculated by using the central difference method and the velocity is calculated by the relative velocity method. The relative velocity method is defined by the relative motion between follower and cam at a center of a follower roller. The central difference method is derived in the 3 dimensional space.

• 한국산학기술학회논문지
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• 제19권6호
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• pp.628-633
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• 2018

GNSS의 정확도는 사용되는 장비에서부터 자료처리에 이르기까지 여러 가지 요인에 의해 그 정확도가 달라진다. 이것은 GNSS에 의한 위치결정이 요구되는 정확도에 따라 다르게 활용될 수 있기 때문이다. 높은 정확도를 요구하는 기준점 측량의 경우는 상대측위 방식으로 측량을 수행하게 되며, 기준점의 등급에 따라 관측시간과 자료처리 s/w가 다르게 사용되고 있다. 그러나 학술용 s/w는 사용자의 숙련도에 따라 그 정확도가 크게 좌우될 수 있어 기선거리가 짧은 경우에는 상업용 s/w를 사용하는 것이 효율성 측면에선 더 나을 수도 있다. 이에 본 연구에서는 GNSS측량 데이터에 대해 학술용 s/w와 상업용 s/w를 이용 자료처리를 수행 그 결과를 비교하였다. 연구 결과 수평위치에서는 2cm 미만의 차이를 나타냈으며, 높이 성과에 있어서는 5cm 미만의 차이를 나타냈다. 이러한 차이는 통합기준점 측량 규정에서 명시하고 있는 오차 범위에 존재하는 것으로 나타났다. 이상의 결과를 토대로 장기선이 아닌 중단기선에서는 상업용 s/w를 활용하여 GNSS 자료처리에 사용할 수 있다는 것을 입증할 수 있었다.

• 한국농공학회논문집
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• 제54권5호
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• pp.69-77
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• 2012

Relative density, used to express dynamics condition of sand quantitatively, is measured by RI Test, Standard Penetration Test and Cone Penetration Test. Each measurement method has demerits, which is complicated or needs a specific analysis instrument and an analysis of expert. Also the ground is in wet condition commonly because of an unsaturated zone between a saturated zone and a surface, so the behaviour of the ground has different engineering properties unlike the dry ground and it diminishes accuracy of measuring relative density. In this study, the correlation between relative density and penetration of fall cone test in dry condition and wet condition with variation of water content was analyzed and a simple measuring method for relative density was suggested. As a result, there were difference of penetration between dry sands and wet sands, the correlation between relative density and penetration showed linear expression and relative density could be measured by the linear relation.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2000년도 춘계학술대회논문집 - 한국공작기계학회
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• pp.367-372
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• 2000

Accuracy of a machined component is determined by the relative motion between the cutting tool and the workpiece. One of the important factors which affects the accuracy of this relative motion is the geometric error of machine tools. In this study, geometric error is modeled using form shaping motion of machine tool, where a form shaping function is derived from the homogeneous transformation matrix. Geometric errors are measured by laser interferometer. After that, the local positioning error can be estimated from the form shaping model and geometric error data base. From this information, we can remodel the part by shifting the design surface to the amount of positional error. By generating tool path to the redesigned surface, we can reduce the machining error.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 합동 추계학술대회 논문집 정보 및 제어부문
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• pp.122-125
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• 2002

The optimal guidance has advantages of accuracy and economic energy consumption but it is difficult to implement due to its dependence on the target information such as the relative range, the relative velocity and the acceleration of target. This paper uses optimal guidance and sliding-mode guidance to obtain a new guidance method. The suggested method shows robustness against target maneuvers, good dynamic performance, energy saving of missile and terminal accuracy. Its effectiveness is demonstrated by the simulation results.

• 대한의용생체공학회:의공학회지
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• 제10권1호
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• pp.25-32
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• 1989

In this study, Rheoencephalography( REG ) was designed and constructed. Using the cons- tructed instrument cerebral blood flow(CBF) of left and right brain, CBF change by posture, and reproducibility were studied. Followings are important results. Relative CBF could be measured noninvasively and continuously. Since reproducibility of the constructed REG was found to be quite high (4%), the accuracy of the instrument itself was proved. REG can be easily applied for testing the effect of drugs for the patients with cerebral vessel diseases since it is quite sensitive to the relative changes of CBF. Various cerebral diseases can be diagnosed by analyzing the REG waveforms. The area of restricted cerebral blood vessels can be located by arranging the electrode configuration. Comparative studies with the standard techinques of measuring CBF are needed to verify the accuracy of REG. Further studies on optimal electrode configuration and various artifacts are also necessary.

• 대한전기학회논문지:전력기술부문A
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• 제48권4호
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• pp.365-370
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• 1999

This paper describes the Weekly Load Forecasting Expert System(Named WLoFy) which was developed and implemented for Korea Electric Power Corporation(KEPCO). WLoFy was designed to provide user oriented features with a graphical user interface to improve the user interaction. The various forecasting models such as exponential smoothing, multiple regression, artificial nerual networks, rult-based model, and relative coefficient model also have been included in WLofy to increase the forecasting accuracy. The simulation based on historical data shows that the weekly forecasting results form WLoFy is an improvement when compared to the results from the conventional methods. Especially the forecasting accuracy on special days has been improved remakably.

• 대한의용생체공학회:의공학회지
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• 제17권4호
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• pp.545-552
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• 1996

Researches on chromosome are very significant in cytogenetics since a gene of the chromosome controls revelation of the inheritance plasma The human chromosome analysis is widely used to diagnose genetic disease and various congenital anomalies. Many researches on automated chromosome karyotype analysis has been carried out, some of which produced commercial systems. However, there still remains much room for improving the accuracy of chromosome classification. In this paper, we propose an algorithm for reconstruction of the chromosDme image to improve the chromosome classification accuracy. Morphological feature parameters are extracted from the reconstructed chromosome images. The reconstruction method from chromosome image is the 32 direction line algorithm. We extract three morphological feature parameters, centromeric index(C.I.), relative length ratio(R.L.), and relative area ratio(R.A.), by preprocessing ten human chromosDme images. The experimental results show that proposed algorithm is better than that of other researchers'comparing by feature parameter errors.

• 한국정밀공학회지
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• 제15권9호
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• pp.127-134
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• 1998

This paper describes the design of a 6-component force/moment calibration machine with having the maximum capacities of 500 N in forces and 50 Nm in moments. To be used for the characteristic of a multi-component load cell. this machine consists of a body, a fixture, a force generating system, a moment generating system and weights. We have also evaluated the accuracy of the calibration machine. Test results show that the expanded relative uncertainty for force components $\pmFx,\;\pmFy\;and\;moment\;components\;\pmMx,\;\pmMy\;are\;less\; than\;8.6\times10^{-4}$, and force components +Fz, -Fz and moment components $\pmMz\;is\;less\;than\;1.6\times10^{-3},\;2.0\times10^{-5},\;1.7\times10^{-3}$ respectively.