• 한국공작기계학회논문집
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• 제16권5호
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• pp.101-107
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• 2007

Assembly is mentioned as important process saving time and cost where we produce the machine with many parts relationships. In this study, parts assembly relationship is analysed for assembly information of micro milling machine which have been developing for research. Liaison diagram, datum flow chain and assembly tree are applied to discuss assembly characteristics of micro milling machine model. We can find out the characteristics of micro machine assembly and discuss about facility of assembly. Some analysis in this paper about micro milling machine will give a useful tools for assembly. We knew that the predicted results from analysis in this study are alignment and clearance among the parts. The 3D model of micro machine which is studied in this paper is not a complete model. Main parts of a micro milling machine are used and presented.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1988년도 한국자동제어학술회의논문집(국내학술편); 한국전력공사연수원, 서울; 21-22 Oct. 1988
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• pp.214-218
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• 1988

This paper suggests mathemathical engine model which can simulate generalized gasoline engine. Suggested engine model contains air/fuel inlet element, intake manifold, combustion, engine dynamics. In order to analyze a gasoline engine, physical characteristics of engine and steady state engine data should be controlled. In adaptation for abrupt change of circumstance or drive conditions, this model can analyze important physical phenomena in the intake manifold by computer simulation. This model can also evaluate statuses of drive under various working conditions precisely. Therfore, this model suggests basic datum to evaluate the engine system which are needed in designing and development of engine controller.

• 한국지리정보학회지
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• 제24권2호
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• pp.78-90
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• 2021

정밀지오이드를 구축하기 위하여 육상, 해상, 항공, 위성 중력측정 방법으로 다양화되고 측정 기술이 발전되어 고해상도 고정밀도의 중력자료 확보가 가능해졌다. 정밀지오이드의 구축은 별도의 수준측량 없이 GNSS 측량을 통해 표고를 빠르고 편리하게 결정할 수 있으며 우리나라는 2014년부터 국토지리정보원에서 GNSS를 기반으로 한 높이측량 정확도를 향상시키기 위해 합성지오이드 모델을 개발하고 있다. 본 연구에서는 공공측량의 GNSS높이측량을 검증하기 위하여 기존의 고시된 공공기준점을 선점하여 GNSS높이측량 결과와 비교 분석하였다. 실험은 연구보고서 등에서 정밀도가 낮은 지역으로 제시되거나 정밀도가 낮을 것으로 예상되는 연안, 접경, 산악지형의 공공기준점에 대하여 GNSS높이측량을 수행하고 정밀도를 분석하였다. GNSS높이측량 검증을 위해 공공기준점 GNSS높이측량 기지점으로 사용될 주변 통합기준점의 GNSS 타원체고를 점검하였다. 점검된 통합기준점을 기준으로 공공기준점의 GNSS 타원체고를 산출하고 KNGeoid18 모델을 이용하여 표고를 계산하여 직접수준측량 표고결과와 비교하였다. 분석 결과 연안, 접경, 산악 지역 공공기준점의 GNSS 높이측량 결과가 3·4급 공공수준측량 정확도에 만족하는 것으로 나타났다. 이를 통하여 사용자가 요구하는 높이 정확도에 따라 기존의 직접수준측량보다 GNSS 높이측량이 효율적으로 이용될 수 있으며, KNGeoid18도 자율주행자동차, 무인항공기 등 다양한 분야에서 활용될 수 있을 것으로 판단된다.

• 한국측량학회:학술대회논문집
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• 한국측량학회 2003년도 추계학술발표회 논문집
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• pp.373-378
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• 2003

This study deals with development of transformation tool for transformation of digital map coordinates systems using by the best fit transformation parameters which are determined between the local geodetic datum and geocentric datum (ITRF2000) in Korea and distortion modelling derived from collocation method. We used 107 control points as a common points. For analyzing the derived parameters, another 83 common points are tested. Finally, the best fit parameters are determined from Molodensky-Badekas model after considering the RMSE, maximum value, minimum values, and 95% confidence interval of residuals. after transformation of best fit parameters and distortion modelling, we could develop transformation tools with advenced accuracy. so it is possible to perform on transformation of digital map with scale 1:5,000. and we tested accuracy eveluation through analysis between transformation results and field results of GPS observation.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1999년도 봄 학술발표회 논문집(I)
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• pp.325-330
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• 1999

The objectives of this study were to compare the development of compressive strength of epoxy resin mortars used as repairing materials with respect to maturity, and to propose a predictive model for strength development of epoxy resin mortar. A series of tests were carried out for the hardener contents of 30, 40 and 50 percentage of resin and compressive strength were measured at the of 6, 12, 24, 72, 120 and 168 hours respectively under temperature of 0, 10, 20 and 3$0^{\circ}C$. The datum temperature was estimated by measured strength, and the maturity is calculated with the estimated datum temperature. The compressive strength of epoxy resin mortar could be predicted by regression analysis from the maturity-compressive strength relationship.

• 산업공학
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• 제4권2호
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• pp.1-12
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• 1991

This paper deals with the development of a computer aided fixture planning system that automatically selects set-ups, set-up sequence and fixture design for prismatic parts. This study presents the hierarchical data structure for feature-based part model and the preprocessing procedure for the proposed system. The preprocessing procedure generates tools such as DDR(Degree of Dimensional Relationship), AMV(Admissible Misalignment Value) and the datum reference frame of each feature according to the proposed decision table. The proposed system is called AFIX(Automated FIXture planning system) which is implemented by using C language on the workstation. A case study for a cavity plate is presented to show the performance of the AFM.

• 한국농공학회지
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• 제42권2호
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• pp.99-107
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• 2000

The objective of this study are to compare the development of compressive strength of epoxy mortars used as repairing materials with respect to maturity , and to propose a model predicting strength development of epoxy mortars. A series of tests are carried out for the hardener contents of 30, 40 and 50 percentage of epoxy resin and compressive strengths are measured at the age of 6, 12, 24, 72, 120 and 168 hours respectively under the cure temperature of 0, 10, 20 and 3$0^{\circ}C$. The datum temperature is estimated by measured strengths, and the maturity is calculated with the estimated datum temperature. The compressive strength of epoxy mortars can be predicted by regression analysis from the maturity-compressive strength relationship.

• 한국농공학회:학술대회논문집
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• 한국농공학회 2003년도 학술발표논문집
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• pp.419-422
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• 2003

The Sumjin Reservoir watershed was simulated by the SSARR model. In order to calibrate the parameters of SSARR model, watershed was divided into three sub-basins with the basin characteristics and the observed runoff datum at estuary of dam were used. As the Results of study, there was not much of difference between the observed runoff and the simulated runoff.

• 한국농공학회논문집
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• 제59권6호
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• pp.19-27
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• 2017

This study investigated to predict the compressive strength of unsaturated polyester resin based polymer concrete using the maturity method. The test results show that the development of the compressive strength increased exponentially until an age of 24 hours. After 24 hours, the development of the compressive strength just increased gradually. This test result shows that the strength of unsaturated polyester resin based polymer concrete was developed mainly at the early age. Estimated datum temperature of unsaturated polyester resin based polymer concrete was $-20.67^{\circ}C$ which was much lower than of datum temperature ($-10^{\circ}C$) of Portland cement concrete. Also, this study result shows that the existing maturity index associated with Portland cement concrete was not applicable for polymer concrete because curing time of Portland cement concrete is different clearly with curing time of polymer concrete. The cause of different curing time was that there were different curing mechanisms between Portland cement concrete and polymer concrete. In order to best apply the experimental data to a model, CurveExpert Professional, the commercial software, was used to determine the predictive model regarding the compressive strength of unsaturated polyester resin based polymer concrete. As a result, Gompertz Relation or Weibull Model was an appropriate model as a predictive model. The proposed model can be used to predict the compressive strength, especially, it is more useful when the maturity is in the range between $40^{\circ}C{\cdot}h^{0.4}$ and $900^{\circ}C{\cdot}h^{0.4}$.

• 한국측량학회지
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• 제32권spc4_2호
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• pp.401-412
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• 2014

지적재조사사업에서는 지적도면을 세계측지계로 변환하는 작업을 추진하고 있다. 본 연구는 이 작업의 효율적 추진을 위한 목적으로 종래의 지적측량성과를 지역측지계 기반에서 조정하여 세계측지계로 좌표변환하는 프로세스를 개발하고 수치실험을 실시하였다. 이 프로세스는 조정좌표의 산출, 조정좌표의 좌표변환, 왜곡량모델링으로 이루어진다. 1단계로 지역측지계 기반의 조정좌표의 산출은 GPS관측의 점간기선거리를 이용하는 삼변망조정계산에 의하였고, 2단계로 조정좌표의 세계측지계 좌표변환은 Affine변환모델에 의하였다. 수치실험에서는 서울시에 소재하는 195점의 동일원점계열의 기준점뿐만 아니라 인천시에 소재하는 61점의 다른 원점계열의 기준점을 통합 활용하는 계산을 실시하였다. 그 결과 조정좌표를 이용하는 좌표변환계산은 특정 공통점의 선택에 관계없이 변환좌표와 관측좌표가 2cm 이내에서 일치하였다. 또, 조정좌표를 이용하는 좌표변환은 변환계산의 지역 범위를 달리하더라도 최종 결과에는 차이가 없었다. 본 연구의 조정좌표를 이용하는 방법은 변환계산의 지역 크기 및 공통점 선택에 무관하게 기준점오차 및 경계점의 왜곡량을 명확히 해주므로 지적재조사사업의 세계측지계 도면변환 과정에서 적합한 왜곡량 보정을 실시한다면 도면의 품질향상을 기할 수 있을 것으로 기대된다.