• 새물리
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• 제68권11호
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• pp.1275-1280
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• 2018

We demonstrated transmission direct phase-measuring deflectometry (DPMD) with a specular phase object having discontinuous surfaces by using two displays and a two-dimensional array detector for display and by recording the distorted fringe patterns. Three-dimensional (3D) information was obtained by calculating the height map directly from the phase information. We developed a mathematical model of the phase-height relationship in transmission DPMD. Unlike normal transmission deflectometry, this method supports height measurement directly from the phase. Compared with other 3D measurement techniques such as interferometry, this method has the advantages of being inexpensive and easy to implement.

• 지질공학
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• 제29권4호
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• pp.565-578
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• 2019

황등 화강암, Berea 사암, 정선 대리암, 홍천 편마암, 풍암 셰일 및 음성 사질 셰일의 여섯 종류의 암석에 대하여 직접전단시험, 기울임시험 그리고 당김시험을 이용하여 기본마찰각을 측정하고, 암종에 따른 기본마찰각의 특성, 시험방법의 정확성을 비교, 검토하여 기본마찰각 측정에 가장 정확하고 효율적인 시험방법을 제시하였다. 기본마찰각은 직접전단시험을 이용하면 정확하게 측정되지만, 비싼 장비와 복잡한 시험절차가 필요하다. 국제암반역학회에서 표준시험법으로 제안한 기울임시험은 직접전단시험에서 측정된 기본마찰각과 유사한 값을 제시하나, 동일한 암석으로 제작된 3개의 시료에서 측정된 기본마찰각은 최대 7° 이상의 오차를 보이고, 1개의 시료에서 5회 측정된 미끄러짐 각 또한 시료에 따라서 증가하거나, 감소하거나, 유사한 값을 보이는 등 일정한 패턴을 보이지 않고 변할 뿐만 아니라, 편마암에서는 최대 12°의 오차를 보여 시험의 신뢰성에 상당한 의문이 든다. 간단한 시험장비와 비교적 낮은 수직응력하에서 실시되는 당김시험은 직접전단시험에서 구한 기본마찰각과 매우 유사한 값을 제공하고, 측정된 값들이 일관성을 보이고 시험절차 또한 매우 간단하여 기본마찰각 측정에 가장 유용한 시험 방법으로 판단된다.

• 한국통신학회논문지
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• 제34권5C호
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• pp.555-560
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• 2009

차량 충돌 위험을 줄이기 위해 거리 측정용 차량 레이더에 대한 연구가 활발히 진행되고 있다. Direct sequence-ultra wideband를 (DS-UWB) 이용한 차량 레이더는 고속으로 이동하는 차량들 사이에서 충분한 시간적인 여유를 두어 목표물까지의 거리를 측정한다. 따라서 UWB 파형을 이용하면 수신기는 거리를 빠르게 측정하여, 충분한 시간적인 여유를 둘 수 있다. 이에 대한 연구가 진행된 바 있으나 본 논문에서는 그보다 간단한 시스템을 기반으로 빠른 처리 속도로 거리를 측정하여 차량 충돌 방지를 위한 시간적 여유를 확보할 수 있는 기법을 제안한다. 그리고 모의실험 결과를 통해 기존 기법보다 빠른 처리 속도를 확인할 수 있다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1995년도 추계학술대회 논문집
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• pp.407-410
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• 1995

Many researches on measurement technology has been made and developed by various methods. Considering the measurement environment with cutting fluid, coolant and the like, contact type measurement methods are mostly used. But contact measurement method has measuring force and so the sensing head becomes worn. By these reasons, we considered sensors not influenced by the former fluid and so can acquire accrate measured values using error compensation due to temperature and vibration. For this purpose, eddy current sensors and Extended kalman Filter Algorithm for processing measured data has been used. In this paper, we present new technology that can be used for measuring workpiece with previous bad environment using direct method and comparison measurement method. We used cylindrical workpieces which were produced by grinding machine for the target.

• 로봇학회논문지
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• 제17권2호
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• pp.183-190
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• 2022

Accurate kinematic parameters of mobile robots are essential because inaccurate kinematic model produces considerable uncertainties on its odometry and control. Especially, kinematic parameters of caster type mobile robots are important due to their complex kinematic model. Despite the importance of accurate kinematic parameters for caster type mobile robots, few research dealt with the calibration of the kinematic model. Previous study proposed a calibration method that can only calibrate double-wheeled caster type mobile robot and requires direct-measuring of robot center point and distance between casters. This paper proposes a calibration method based on geometric approach that can calibrate single-wheeled caster type mobile robot with two or more casters, does not require direct-measuring, and can successfully acquire all kinematic parameters required for control and odometry. Simulation and hardware experiments conducted in this paper validates the proposed calibration method and shows its performance.

• 한국정밀공학회지
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• 제17권5호
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• pp.124-130
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• 2000

For measuring out the submicron order straightness, a precision measuring device is developed in this paper. The device is constructed with a hydrostatic feed table and a capacitive type sensor which is mounted to the feed table. Straightness is acquired as substracting the motion error of feed table from the measured profile with probe. Motion error of feed table is simultaneously compensated upto 0.120${\mu}{\textrm}{m}$ of linear motion error and 0.20arcsec of angular motion error using the active controlled capillary. Reversal method and strai호t-edge is used fur estimating the measuring accuracy and from the experimental result, it is verified that the device has the measuring accuracy 0.030m. Also, through the practical application on the measurement of ground surface, it is confirmed that the device is very effective to measure the submicron order straightness.

• 복식
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• 제53권5호
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• pp.1-12
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• 2003

This paper proposes a system for measuring the 3D human bodies using the multiple 2D images. The system establishes the multiple image input circumstance from the digital camera for image measurement. The algorithm considering perspective projection leads us to estimate the 3D human bodies from the multiple 2D images such as frontal. side and rear views. The results of the image measurement is compared those of the direct measurement and the 3D scanner for the total 40 items (12 heights, 15 widths and 13 depths). Three persons measure the 40 items using the three measurement methods. In comparison of the results obtained among the measurement methods and the persons, the results between the image measurement and the 3D scanner are very similar. However, the errors for the direct measurement are relatively larger than those between the image measurement and the 3D scanner. For example, the maximum errors between the image measurement and the 3D scanner are 0.41cm in height, 0.39cm in width and 0.95cm in depth. The errors are acceptable in body measurement. Performance of the image measurement is superior to the direct. because the algorithm estimates the 3D positions using the perspective projection. In above comparison, the image measurement is expected as a new method for measuring the 3D body, since it has the various advantages of the direct measurement and 3D scanner in performance for measurement as well as in the devices, cost, Portability and man power.

• 대한치과보철학회지
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• 제42권2호
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• pp.238-247
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• 2004

Statement of problem: Major objective in making on implant-supported prosthesis is the production of superstructure that exhibits a passive fit when connected to multiple abutments. One requirement to ensure passive fit is to make an accurate impression. Purpose : The purpose of this study was to compare the accuracy of master cast fabricated by using different impression methods at the different impression levels. Material and method: The master model used in this study was resin block having low implant analogs. Impression method studied were 1) direct method on fxiture level (Group FIX-D), 2) indirect method on fixture level(Group FIX-I), 3) modified indirect method on fixture level(Group FIX-M), 4) direct method on abutment level(Group AB-D) and 5) indirect method on abutment level(Group AB-I). Each of the five groups took 10 impressions. Fifty impressions were made for master cast by using Impregum $F^{(R)}$ impression material loaded on individual tray. Three dimensional measuring microscope was used to measure the inter-implant distance. Error rate of each inter-implant distance were calculated and evaluated. Results : The results were as follows. 1. Group FIX exhibited higher accuracy than group AB. 2. In group FIX, modified indirect method showed the highest accuracy, while indirect method showed the lowest accuracy. In group Ab, indirect method showed the higher accuracy than direct method. 3. Group FIX showed larger horizontal error than group AB. But, group AB showed the larger vertical error than group FIX. 4. Group Fix-M showed smallest vertical and horizontal error. Conclusion: An impression method have more effect on accuracy of master model than an impression level. A modified indirect method showed smallest vertical and horizontal error.

• 복식문화연구
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• 제11권1호
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• pp.11-19
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• 2003

This study suggests the new 2D anthropometric method using digital camera. It is used MK2001 program that can convert 2D measurements to 3D measurements. To improve that it is measured 100 college students with direct and indirect anthropometric method. The measurements were processed by the SPSS ver10 Statistical Package. The average, standard deviation, and t-test were calculated for each category. Most measurements by 2D measurements are higher than direct measurements but degree. The difference between direct and indirect measurements is less than 2cm. In the results of t-test, height measurements including other 16 measurements which is easy to measure have no meaningful difference within 1cm. The depth measurements are most high difference. The result of each measurement proves that MK2001 program (2D anthropometry method using digital camera) is available for measuring the human body.

• 지식경영연구
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• 제10권2호
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• pp.49-63
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• 2009

In this study, sub domain of flow was investigated on literature survey, and suggested of the measuring method of web-site flow and its simulation analysis. Constructing of measuring method of flow, and using this method what-if analysis was simulated when several condition changed. Using causal map approach to extract knowledge from web-site domain experts and to derives a causal relationship of knowledge. Specially, in our study, describes method of developing and building causal map, and suggests guide line of this method on practical application. This research results show that web-site flow starts "direct searching" or "interesting of special issue(domain)", and when challenges of web-site were accorded with user's skills web-site flow grows. Further, in the web-site, information searching intention results in increase of user's duration time and experience flow to discovery new interesting issues in this process. If user's web-site of interaction is increased, awareness of environment conditions decreased, finally, user's telepresense results in increased web-site flow. This paper contained thai this method make used of measuring flow in the web-site and developing of practical strategy.