• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.27 no.1
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• pp.37-45
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• 2001

The errors in orthognathic surgery can occur during the preoperative preparations including the model surgery, but till now there's been some lack of reserches about them. So we wanted to verify the accuracies in measurements used in model surgery. We compared the accuracy of measurements by vernier calipers, which has been the main measurement tool for conventional model surgery, and that by height gauge, which is recently claimed to be more accurate, with 3 dimensional coordinate analyzer. We could have following results and have a plan to use them for the invention of new model surgery techniques. 1. The measurement errors in Group 1, which mean the difference between "the measurements by 3-D analyzer"and "the measurements by height gauge", were small enough with the range of $0.1{\sim}0.2mm$ in all planes. 2. The mean error in Group 2, which is the differences between the measurements of 3-D analyzer and those of vernier calipers, was 1.1mm. 3. The measurement errors in Group 2 were variable according to the factors including the differences of individuality and expertness of each measurers. But in case of Group 1, they were small and not variable by the expertness. 4. The measurements were more accurate at the points in anterior teeth than in molar teeth in Group 1 and 2. 5. The errors after model surgery increased remarkably, compared with those before surgery in Group 2. And the situation was different in Group 1 in that errors decreased after surgery. According to these results, it assumed that the measurements with height gauge during the model surgery for orthognathic surgery are accurate enough and can be maintained, regardless of complexity of models, individuality, or expertness of measurers.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.13 no.5
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• pp.331-337
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• 2020

The study is underway with the goal of developing an app that will replace vernier calipers using a smartphone's high-performance camera. The specifications of the camera mounted on recent smart phones have evolved so that usually has a 12 Mpixels of image sensor and its size of the pixel is 1.4㎛ and the size of the image sensor is 1 / 2.55 in. The proposed algorithm will apply to develop a precision measuring application that will compete with the Vernier calipers. Most existing applications cannot guarantee an accuracy in scale because the scale of the ruler displayed on the image is unclear or the size of the measurement object varies depending on the distance between the camera and the measurement object. In addition, another accurate measuring tools using lasers are also available, but they are limited because they are expensive. Therefore, if easy-to-carry and precise applications are developed, it is possible to substitute existing measurement tools. The proposed correction algorithm is an algorithm that automatically corrects the distorted source image using the shape and size information of the known template. The e-calipers are applications that display the distance when the area to be measured is specified in the corrected image.

• The Journal of Advanced Prosthodontics
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• v.4 no.2
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• pp.72-75
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• 2012

PURPOSE. This study evaluated the existence of golden proportion between the widths of the maxillary and mandibular anterior teeth in Indian population. MATERIALS AND METHODS. The clinical tooth width measurements were recorded with the digital vernier calipers on 576 patients of both sexes in the age group of 21 - 30 years. Flexible ruler was used to determine the width of maxillary and mandibular anterior teeth on the patients by the same operator. The data obtained was statistically analyzed using paired student t-test (${\alpha}$=.05). RESULTS. The golden proportion was not found between the width of the right central and lateral incisors in 53% of women and 47% of men. The results revealed the golden percentage was rather inconstant in terms of relative tooth width. CONCLUSION. The golden proportion is an inappropriate method to relate the successive widths of the maxillary anterior teeth in Indian population.

• Transactions on Control, Automation and Systems Engineering
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• v.2 no.3
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• pp.214-219
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• 2000

This paper presents a recoil and counter recoil motion measurement system using linear variable differential transformers (LVDT). The output of the LVDT is obtained from the differential voltage of the secondary transformers. Since a transducer core is attached to the motion body, the output is directly proportional to the movement length of the core. Displacement, velocity and acceleration are measured from the LVDT. With a comparison between the measurement result and the reference value obtained by the highly accurate Vernier calipers, it is proved that the measurement system with the LVDT is applicable to the test of the moving part of the mechanism with better accuracy.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2003.04a
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• pp.288-292
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• 2003

The main purpose of this paper is the development of the system which measures the earing rate of aluminum CAN with the CCD camera. In order to optimize imput image, the image object was segregated and the position of the image grasped. In the pre-processing the edges were detected by the Robert mask after improving the definition of image by the histogram equalization. The height of four each ear and angles which occur due to the characteristics of the aluminum CAN are measured manually with the digital vernier calipers in the industrial ground and in the case of the velocity, these require 30 seconds at least by three times measurement per height of one direction of the aluminum. But it took 0.02 seconds when this system was applied. Therefore this system is proven the satisfactory efficiency and reliability as compared to the control result of in industrial ground.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.25 no.3
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• pp.164-170
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• 2016

A proposed pneumatic cylinder-driven roll feeder and an air press were designed to be operated automatically by a PLC. The accuracy of the intermittent feed pitch of the roll feeder was evaluated by measuring lengths of cut-offs of a strip stock by a digimatic vernier caliper. At each predetermined feed pitch, the proposed roll feeder was tested 100 times by varying the feed/cut intervals as 2.0/1.5, 3.0/2.0, and 3.5/2.5 s as test sets. The lengths of the cutoffs of the strip stock ranged from 9.89-10.34, 12.1-12.65, and 15.21-15.67 mm at the predetermined 10, 12, and 15 mm feed pitch, respectively, among the total of 300 samples in each feed pitch, regardless of the feed/shear interval. Therefore, the feed/cut interval at each selected feed pitch was found to have no effect on the accuracy of the intermittent advancing of the strip stock.

• Transactions of the Korean Society of Automotive Engineers
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• v.4 no.3
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• pp.61-72
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• 1996

In this paper, the driver seat comfort of eight automobiles was studied. The joint angles and anthropometric data of eleven subjects sitting on the seating buck were investigated using the instrument devices such as scale, goniometer, vernier calipers, protractor, Martin set. The joint angles of the most comfort posture were found by experiment and compared with previous studies. The anthropometric data of Korean(1992 year surveys) and American(1970∼1974 year) were applied to evaluate the driver seat layout of Korean automobile. The joint angles of the most comfort posture for eleven subjects were obtained with experimental results. The joint angles were agreed with reference angles. The driver seat layout was not suited to seat length and acceleratorseatpan forward distance in 5 percentiles female, pedal separation and seatpan-roof height in 95 percentiles male. Korean automobiles were not suited to seatpan length and steering wheelseatpan clearance, floor-roof height for American 95 percentiles male. The driver anthropometric dimensions were more suitable to middle size than small size automobiles.

• Journal of the Optical Society of Korea
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• v.12 no.3
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• pp.157-161
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• 2008

A wavelength-selective reflector, composed of a double-ring-resonator add/drop filter and a loop-back mirror at the drop port to be used for a hybrid-integrated tunable laser is designed and fabricated. High-index-contrast polymer waveguide is used to realize a compact device as small as $2mm{\times}0.4mm$. The radii of the rings are slightly different from each other to obtain a wide wavelength tuning via a vernier effect. Peak reflectivity is measured to be 52% for TE mode and polarization-dependent wavelength shift is 0.95 nm. The tuning range is measured to be about 42 nm for applied current as small as 46 mA.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.48 no.11
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• pp.1410-1416
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• 1999

This paper aims at investigating the operating-mode characteristics of two-module Thyristor Controlled Series Compensator (TCSC) as an equivalent of the multi-module TCSC in a simple three-phase power transmission system. The load flow program is developed to analyze the steady-state characteristics of two-module TCSC system and to find the thyristor firing angles for the required real power flow. The stability calculation program is developed with Poincare mapping theory. Simulation studies of the TCSC power transmission system using EMTP are performed to evaluate the transient characteristics of two-module TCSC as a real power flow controller and to rpove the results of the load flow calculation and the stability analysis. In the process of the study, the operating-mode characteristics of two-module TCSC are evaluated and compared to those of single-module TCSC.

• The Journal of the Korean dental association
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• v.12 no.1
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• pp.37-42
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• 1974

To ascertain if the ultrasonic cleaning technique caused any dimensional changes in heat and cold curing and fluid resin denture bases and in addition to evaluate the dimensional changes of the resin denture bases stored in water and air, the author measured the distance between the outsides of two pins embedded in methyl methacrylate test denture bases by mean of 12 inch vernier caliper, accurate to 0.02mm. The results were as follows; (1) Ultrasonic cleaning didn't cause any permanent dimensional changes, but only affected temporary dimensional expansion in 16 test denture bases. (2) Temporary expansion rate caused by 10 minutes' ultrasonic cleaning was 0.29% and at the maximal temperature of the cleaning solution it was 0.64%. (3) The half of the denture bases stored in water showed the dimensional expansion rate of 0.47% while the others stored in air showed the dimensional shrinkage rate of 0.15% after 4 months.