• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 춘계학술대회 논문집
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• pp.1543-1546
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• 2005

This paper presents a method to measure a large surface shape using atomic force microscopy, which has been used mostly for measuring over very tiny surfaces. Experiments are performed to measure a step height and a slope of a test sample. The proposed method is rigorously compared with the coordinate measuring machine. The repetition accuracy and the effects of the set point are also studied. The experimental results show that the proposed method is reliable and should be effective to measure both the nano-accuracy surface profile as well as the micro-accuracy global shape of a macro/micro parts using atomic force microscope.

• Tribology and Lubricants
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• 제23권3호
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• pp.83-88
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• 2007

This paper presents measurement processes of rotational accuracy and comparison of theoretical values in the main bearing of scroll compressor. The main bearing is a type of oil journal bearing, but it has an axial or helical groove. The generalized coordinate system method, which can handle this groove, is applied to calculate the pressure profile in the journal bearing. The orbits of journal shaft are calculated corresponding to the compressed gas forces and bearing reaction forces. Then, the orbits are measured using three-point method. The results are compared to that from analyses.

• 대한기계학회논문집
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• 제18권5호
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• pp.1182-1191
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• 1994

This paper presents an enhanced method of slit beam projection intended for the rapid measurement of 3-dimensional surface profiles of dies and molds. Special emphasis is given to optimizing the design of optical system so that the measuring accuracy can be maximized by adopting two-plane camera calibration together with sub-pixel image processing techniques. Finally, several measurement examples are discussed to demonstrate that an actual measuring accuracy of $\pm$ 0.2 mm can be achieved over the measuring range of 500 mm{\times}300mm{\times}200mm$.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2000년도 추계학술대회 논문집
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• pp.838-841
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• 2000

To improve the accuracy of products and improve the product quality, we need to enhance the machining accuracy of the machine tools. To this point of view, measurement and inspection of finished part as well as error analysis of machine tools has been studied for last several decades. OMM(On the Machine Measurement) has been issued to alternate with CMM, pointing out disadvantages of high expenses and lots of setting time in CMM. In this paper, we study 1) the spherical surface manufacturing by volumetric error compensation of machine tool, 2) the system development of OMM without detaching work piece from a bed of machine tool after working. 3) the generation of the finished part profile by On the machine measurement. Furthermore, the output of OMM is compared with that of CMM, and verified the feasibility of the measurement system.

• 한국기계가공학회지
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• 제16권4호
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• pp.1-8
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• 2017

This paper concerns the possibility of 3D printing reverse idle gears for tractor transmission. For the purposes of this experiment, idle gears were manufactured using a SLA 3D printer, FDM 3D printer, and through machining. The accuracy of the idle gears produced in these three different ways were evaluated by the properties of their outer diameter, inner diameter, roundness, concentricity, parallelism, span, backlash, and gear grade. The tooth characteristics of the idle gears were evaluated by their profile, lead, and the pitch of the gears. The results of this experiment determined that the surface conditions created by the finishing process had a significant impact on the dimensional accuracy of the gears and the characteristics of their teeth.

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part2
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• pp.756-757
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• 2006

P/M enables the economical production of components for many kinds of gears. Functionally, the sub gear requires high tooth accuracy and bending fatigue strength. The whole tooth profile was sized after sintering to satisfy the gear tooth accuracy specification. The part was redesigned to reduce machining requirements. The required bending fatigue strength was achieved through appropriate material choice and induction of compressive residual stress by shotpeening after carburizing. The P/M sub gear replaced a forged steel gear, satisfied performance requirements, expanded the use of P/M applications and provided over 30% cost reduction.

• 응용통계연구
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• 제32권2호
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• pp.187-198
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• 2019

ROC와 CAP 곡선을 이용하여 다양한 정확도 측도를 바탕으로 최적분류점을 추정하는 많은 연구가 있다. 본 연구에서는 ROC와 CAP 곡선의 특정한 부분 면적을 나타내는 대안적인 통계량을 제안한다. 새롭게 정의된 부분 면적을 나타내는 통계량의 미분방정식을 이용하여 ROC와 CAP 함수와의 관계를 살펴보고, 다음으로는 ROC와 CAP 곡선에 대한 다양한 정확도 측도들의 조건에서의 최적분류점과의 관계를 유도한다. 혼합분포를 구성하는 두 종류의 분포함수를 다양한 정규분포로 가정하여 최적분류점을 설정하고, 다양한 정확도 측도들의 조건에서의 최적분류점에 대응하는 제1종과 제2종 오류의 크기를 탐색하고 토론한다.

• 한국지반환경공학회 논문집
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• 제17권8호
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• pp.39-44
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• 2016

도심지와 같이 공사 현장에 인접 구조물이 많은 경우, 지반 구조물의 안정성 확보와 더불어 지반의 변형 역시 엄격하게 관리해야 한다. 따라서 공사 중 현장에서 발생하는 지반의 침하를 정확하게 계측하는 것은 매우 중요하다. 지반의 침하는 침하계를 이용하여 계측하는 것이 일반적이나, 최근 전자기술의 발달로 3차원 스캔이 가능한 장치들을 지반 침하 계측에 사용하고 있다. 그러나 이 3차원 스캔장치의 경우 지반 침하의 전체적인 양상을 평가하기는 용이하나 직접 침하를 측정하지 않아 정밀도에 있어서 한계가 있다. 또한, 침하계의 경우 침하계가 설치된 지점에서만 침하값을 측정하기 때문에 전체적인 침하의 양상을 평가하는 데는 한계가 있다. 본 논문에서는 침하계가 측정한 값과 스캐너가 측정한 값을 합성하는 조건부 합성 기법에 대해 연구하였다. 가상의 침하양상과 이를 바탕으로 가상의 스캔한 침하 양상을 생성시켜 연구를 진행하였다. 조건부 합성을 통해 침하 양상의 오차를 획기적으로 줄일 수 있는 것으로 나타났다.

• 천문학회지
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• 제55권1호
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• pp.11-22
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• 2022

We introduce the Transformable Reflective Telescope (TRT) kit that applies an aluminum profile as a base plate for precise, stable, and lightweight optical system. It has been utilized for optical surface measurements, developing alignment and baffle systems, observing celestial objects, and various educational purposes through Research & Education projects. We upgraded the TRT kit using the aluminum profile and truss and isogrid structures for a high-end optical test device that can be used for prototyping of precision telescopes or satellite optical systems. Thanks to the substantial aluminum profile and lightweight design, mechanical deformation by self-weight is reduced to maximum 67.5 ㎛, which is an acceptable misalignment error compared to its tolerance limits. From the analysis results of non-linear vibration simulations, we have verified that the kit survives in harsh vibration environments. The primary mirror and secondary mirror modules are precisely aligned within 50 ㎛ positioning error using the high accuracy surface finished aluminum profile and optomechanical parts. The cross laser module helps to align the secondary mirror to fine-tune the optical system. The TRT kit with the precision aluminum mirror guarantees high quality optical performance of 5.53 ㎛ Full Width at Half Maximum (FWHM) at the field center.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2005년도 추계종합학술대회
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• pp.991-994
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• 2005

In the uni-directional broadcasting environments, almost TV programs are scheduled depending on the viewers' popular watching time, and the advertisement contents in these TV programs are mainly arranged by the popularity and the ages of the audience. However, the advertisement programs which support the TV programs the audiences want are not served to the appropriate audiences efficiently. In this paper, we propose the prototype of target advertisement system for the appropriate distribution of the advertisement contents. The proposed target advertisement system estimates the audience's profile without private information and provides the target advertisement contents by using his/her inferred profile. And we show the accuracy of the proposed algorithm, Multistage Classifier, for the target advertisement system and the implementation of our target advertisement system.