• Journal of the Korean Society for Precision Engineering
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• v.19 no.3
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• pp.39-45
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• 2002

A simple and low cost stylus profiler made of ferrite cores is developed. The devised profiler consists of a contact probe, a measuring transducer, a signal processing unit, and a motorized stage. The contact probe attached to 4-bar spring maintains sufficient stiffness to protect disturbances. An overlap-area type inductive position sensing system is selected as a measuring transducer, which has high sensitivity, repeatability and linearity. The transducer is composed of coil bundles and ferrite cores which have good electromagnetic characteristics in spite of low cost. The repeatability of the profiler with the proposed inductive sensing system is better than 50nm. Experimental results are shown that the proposed profiler can measure the line or 3D profile of an object with sub-micron features.

• Journal of Radiation Industry
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• v.17 no.4
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• pp.377-384
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• 2023

In this study, the image quality assessment, especially spatial resolution evaluation, for Sparse-view CT reconstructed images was performed. The main goal of the experiment is to evaluate Modulation Transfer Function by using American Standard Method for Measurement of Computed Tomography System Performance(ASTM E1695-95) which uses the edge test object. To compare with the ASTM method, a different method, the radial-type edge profile, to measure MTF using the edge method also performed. Both approaches were tested on the same image acquired by the stationary-gantry sparse-view CT security-screening system using cylindrical test phantom manufactured in accordance with ANSI 42.45. Both of the spatial resolutions at 10% modulation are 0.195, 0.203lp pixel^-1, respectively. The method implemented by ASTM E1695-95 showed higher reliability and had a relatively more accurate spatial resolution result than the radial-type edge profile method.

• Journal of the Korean Society for Precision Engineering
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• v.34 no.2
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• pp.107-114
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• 2017

In this investigation, we describe a metrological technique for surface and thickness profiles of a silicon (Si) wafer by using a 6 degree of freedom (DOF) stitching method. Low coherence scanning interferometry employing near infrared light, partially transparent to a Si wafer, is adopted to simultaneously measure the surface and thickness profiles of the wafer. For the large field of view, a stitching method of the sub-aperture measurement is added to the measurement system; also, 6 DOF parameters, including the lateral positioning errors and the rotational error, are considered. In the experiment, surface profiles of a double-sided polished wafer with a 100 mm diameter were measured with the sub-aperture of an 18 mm diameter at $10\times10$ locations and the surface profiles of both sides were stitched with the sub-aperture maps. As a result, the nominal thickness of the wafer was $483.2{\mu}m$ and the calculated PV values of both surfaces were $16.57{\mu}m$ and $17.12{\mu}m$, respectively.

• 한국지구물리탐사학회:학술대회논문집
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• 2004.08a
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• pp.49-69
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• 2004

One of the important roles of geophysical exploration in archeological survey may be to provide the subsurface information for effective and systematic excavations of historical remains. Ground Penetrating Radar (GPA) can give us images of shallow subsurface structure with high resolution and is regarded as a useful and important technology in archeological exploration. Since the buried cultural relics are the three-dimensional (3-D) objects in nature, the 3-D or areal survey is more desirable in archeological exploration. 3-D GPR survey based on the very dense data in principle, however, might need much higher cost and longer time of exploration than the other geophysical methods, thus it could have not been applied to the wide area exploration as one of routine procedures. Therefore, it is important to develop an effective way of 3-D GPR survey. In this study, we applied 3-D GPR method to investigate the possible historical remains of Baekje Kingdom at Gatap-Ri, Buyeo city, prior to the excavation. The principal purpose of the investigation was to provide the subsurface images of high resolution for the excavation of the surveyed area. Besides this, another purpose was to investigate the applicability and effectiveness of the continuous data acquisition system which was newly devised for the archeological investigation. The system consists of two sets of GPR antennas and the precise measurement device tracking the path of GPR antenna movement automatically and continuously Besides this hardware system, we adopted a concept of data acquisition that the data were acquired arbitrary not along the pre-established profile lines, because establishing the many profile lines itself would make the field work much longer, which results in the higher cost of field work. Owing to the newly devised system, we could acquire 3-D GPR data of an wide area over about $17,000 m^2$ as a result of the just two-days field work. Although the 3-D GPR data were gathered randomly not along the pre-established profile lines, we could have the 3-D images with high resolution showing many distinctive anomalies which could be interpreted as old agricultural lands, waterways, and artificial structures or remains. This case history led us to the conclusion that 3-D GPR method can be used easily not only to examine a small anomalous area but also to investigate the wider region of archeological interests. We expect that the 3-D GPR method will be applied as a one of standard exploration procedures to the exploration of historical remains in Korea in the near future.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.20 no.6
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• pp.101-107
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• 2020

Road surface measurement is an essential process for quantifying the degree and displacement of roughness in road surface management. For safer road surface management and quick maintenance, it is important to accurately measure the road surface while mounted on a vehicle. In this paper, we propose a sophisticated road surface measurement system that can be measured on a moving vehicle. The proposed road surface measurement system supports more accurate measurement of the road surface by using a high-performance line laser sensor. It is also possible to measure the transverse and longitudinal profile by matching the position information acquired from the RTK, and the velocity adaptive update algorithm allows a manager to monitor in a real-time manner. In order to evaluate the proposed system, the Gocator laser sensor, MRP module, and NVIDIA Xavier processor were mounted on a test mobile and tested on the road surface. Our evaluation results demonstrate that our system measures accurate profile base on the MSE. Our proposed system can be used not only for evaluating the condition of roads but also for evaluating the impact of adjacent excavation.

• Transactions of the Korean Society of Automotive Engineers
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• v.5 no.3
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• pp.54-65
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• 1997

To quantify the LII signals from soot particle of flames in diesel engine cylinder, a new method has been proposed for correcting LII signal attenuated by soot particles between the measuring point and the detector. It has been verified by an experiment on a laminar jet ethylene-air diffusion flame. Being proportional to the attenuation, the ratio of LII signal at two different detection wavelengths can be used to correct the measured LIIsignal and obtain the unattenuated LII signal, from which the soot volume fraction in the flame can be estimated. Both the 1064-nm and frequency-doubled 532-nm beams from the Nd : YAG laser are used. Single-shot, one-dimensional(1-D) line images are recorded on the intensified CCD camera, with the rectangular-profile laser beam using 1-mm-diameter pinhole. Two broadband optical interference filters having the center wavelengths of 647 nm and 400 nm respectively and a bandwidth of 10 nm are used. This two-wavelength correction has been applied to the ethylene-air coannular laminar diffusion flame, previously studied on soot formation by the laser extinction method in this laboratory. The results by the LII measurement technique and the conventional laser extinction method at the height of 40 nm above the jet exit agreed well with each other except around outside of the peaks of soot concentration, where the soot concentration was relatively high and resulting attenuation of the LII signal was large. The radial profile shape of soot concentration was not changed a lot, but the absolute value of the soot volume fraction around outside edge changed from 4ppm to 6.5 ppm at r=2.8mm after correction. This means that the attenuation of LII signal was approximately 40% at this point, which is higher than the average attenuation rate of this flame, 10~15%.

• Journal of ILASS-Korea
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• v.25 no.1
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• pp.8-14
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• 2020

Recently, 1-D model-based engine development using virtual engine system is getting more attention than experimental-based engine development due to the advantages in time and cost. Injection rate profile is the one of the main parameters that determine the start and end of combustion. Therefore, it is essential to set up a sophisticated model to accurately predict the injection rate as starting point of virtual engine system. In this research, procedure of 1-D model setup based on AMESim is introduced to predict the dynamic behavior and injection rate of diesel injector. As a first step, detailed 3D cross-sectional drawing of the injector was achieved, which can be done with help of precision measurement system. Then an approximate AMESim model was provided based on the 3D drawing, which is composed of three part such as solenoid part, control chamber part and needle and nozzle orifice part. However, validation results in terms of total injection quantity showed some errors over the acceptable level. Therefore, experimental work including needle movement visualization, solenoid part analysis and flow characteristics of injector part was performed together to provide more accuracy of 1-D model. Finally, 1-D model with the accuracy of less than 10% of error compared with experimental result in terms of injection quantity and injection rate shape under normal temperature and single injection condition was established. Further work considering fuel temperature and multiple injection will be performed.

• Journal of Physiology & Pathology in Korean Medicine
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• v.23 no.2
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• pp.512-519
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• 2009

Among patients who visited each clinical department for oriental medical treatments, anthropometric measurement, blood pressure, fasting blood glucose and blood lipid profile level were measured at their first initial visit. 55 subject patients who were diagnosed as having metabolic syndrome and 150 mg/dL or more of triglyceride were selected as subjects whose fasting blood glucose, triglyceride, total cholesterol, HDL cholesterol and LDL cholesterol were measured after fasting. According to each patient's disease, the subject received treatments such as herb medicine, acupuncture, moxibustion, cupping therapy, physical therapy and rehabilitation therapy from each clinical department, and after an average of 4.10${\pm}$0.31 weeks, another test was performed yielding the following results. Serum triglyceride was 243.72${\pm}$13.05 mg/dL before the oriental medical treatment and 188.11${\pm}$12.17 mg/dL after the treatment where although it continued to show an abnormal value even after the treatment, there was statistically significant decrease compared to pre treatment(P<0.05). Serum total cholesterol was 207.50${\pm}$5.89 mg/dL before the oriental medical treatment and 192.37${\pm}$5.53 mg/dL after the treatment which was statistically insignificant compared to pre treatment(P>0.05). Serum HDL cholesterol was 51.19${\pm}$3.95 mg/dL before the oriental medical treatment and increased to 52.53${\pm}$1.49 mg/dL after the treatment although it was statistically insignificant compared to pre treatment(P>0.05). Serum LDL cholesterol was 110.66${\pm}$5.86 mg/dL before the oriental medical treatment and decreased to 106.12${\pm}$4.82 mg/dL after the treatment although it was statistically insignificant compared to pre treatment(P>0.05). In regards to the change of triglyceride for each sex, it was 221.84${\pm}$14.01 mg/dL before the treatment and 187.00${\pm}$15.47 mg/dL after the treatment for men, and it was 271.50${\pm}$22.78 mg/dL and 189.53${\pm}$19.76 mg/dL respectively for women where even though men and women showed the decrease of 34.84${\pm}$12.79 mg/dL and 81.96${\pm}$20.01 mg/dL respectively, both men and women continue to show abnormal values after the treatments. However, there was statistically significant decrease compared to pre treatment(P<0.05). In regards to the change of total cholesterol for each sex, with 198.24${\pm}$7.60 mg/dL for men before the treatment and 188.93${\pm}$7.45 mg/dL after the treatment, values for both before and after the treatment were within the normal range where the change value was 9.30${\pm}$5.86 mg/dL and statistically insignificant(P>0.05). For women, it was 219.26${\pm}$8.87 mg/dL and 196.73${\pm}$8.43 mg/dL respectively for women where with 22.53${\pm}$7.60 mg/dL, it decreased to the normal level after the treatment, and there was a statistically significant decrease compared to pre treatment(P<0.05). With such results, serum triglyceride and cholesterol levels of patients who have been diagnosed as having metabolic syndrome were observed to decrease after the oriental medical treatment. Especially, for both men and women, abnormally high triglyceride level decreased while the effect of lipid profile improvement for women was more significant compared to men.

• Journal of the Korean Society for Precision Engineering
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• v.18 no.6
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• pp.159-165
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• 2001

Recently Moire and PMP(Phase Measuring Profilometry) are adopted as a practical methodology for non-contact 3-D measurement of free surface. These methods extract the 3-D informations from the images of the object projected with stripe-pattern light. This paper presents a simple projector generating stripe-pattern light using expensive polygon mirror. In this projector, slit-beam is generated with a Laser diode and a rod lens and the laser diode is switched on/off synchronizing with the rotation of the polygon mirror. So its structure is very simple and light-weighted compared to the existent projection methods using several lenses and it is also easy to change the pitch and the phase of the stripe pattern. Experimental results show that the intensity profile of the stripe pattern can be approximated with sinusoidal curve by reducing the pitch of the stripe pattern.

• Journal of the Korean Institute of Telematics and Electronics D
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• v.34D no.12
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• pp.46-53
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• 1997

The TMA gas sensors are fabricated with the ZnO-based thin films grown by a RF magnetron sputtering method. The hall effect measurement and AES analysis are carried out to investigate the effects of the sputtering gases and dopants which effect on the electrical resistivity and sensitivity to TMA gas. We measure the cfhanges of the surface carrier concentration, haall electron mobility, electrical resistivity, surface condition, and depth profile of the films. The ZnO-based thin film sensors sputtered in oxygen, or added with dopants showed a high sruface carrier concentration, film sensors sputtered in oxygen and doped with 4.0 wt.% $Al_{2}$O$_{3}$, 1.0 wt.% TiO$_{2}$, and 0.2 wt% v$_{2}$O$_{5}$ showed the highest surface carrier concentration of 5.952 * 10$^{20}$ cm$^{-3}$ , hall electron mobility of 176.7 cm$^{2}$/V.s, lowest electrical resistivity of 6*10$^{-5}$ .ohm.cm and highest sensitivity of 12. These results were measured at a working temperature of 300.deg. C to 8 ppm TMA gas.