산업화와 도시화의 급속한 발전으로 교통량이 증가하면서, 도로 비산먼지와 같은 대기 오염 문제가 심각해지고 있다. 특히, 도로에 서 발생하는 미세먼지의 주요 원인인 비배기가스의 일환인 도로 비산먼지(Road suspended dust)는 대기 질을 저하시킬 뿐만 아니라, 인 체 건강에도 여러 가지 해로운 영향을 미친다. 이에 비산먼지 예측 모형식을 개발하기 위해 도심부 도로 내 비산먼지 측정차량을 운 영하고 있으나, 측정 시 주변 환경에 영향을 많이 미치기 때문에 보다 신뢰성 있는 결과를 위해서는 앞차에서 발생하는 배기가스 영 향권을 최소화하여 노면-타이어에서 발생하는 순수 비산먼지 농도를 측정할 필요가 있다. 따라서 본 연구의 목적은 차량의 주행 패턴 에 따라 도로 비산먼지 농도가 어떻게 변화하는지를 분석하고, 거리별 배기가스의 영향력을 평가하고자 하였다. 먼저, 이동식 비산먼지 측정차량을 활용하여 측정차량을 기준으로 차량 간의 거리(10m, 20m, 50m)와 도심부에서 발생할 수 있는 대표 적인 주행행태(전방 2대 직진, 전방 2대 평행, 전방 3대 직진)에 따른 도로 비산먼지 농도의 변화를 측정하였다. 실험 결과, 차량 간 거리가 가까운 10m일 때 비산먼지 농도가 가장 높았으며, 이 때의 농도는 20m 또는 50m 거리에서 측정된 농도보다 유의미하게 증가 하는 경향을 보였다. 특히, 20m 거리에서는 비산먼지 농도가 낮아지는 경향이 뚜렷하였으며, 이는 차량의 배기가스가 도로에서 발생하 는 비산먼지에 미치는 영향이 줄어드는 것을 나타낸다. 또한 전방에 3대의 차량이 직진으로 주행할 경우 앞차량에 의해 비산된 먼지 가 계속 공기중으로 비산되어 측정차량에서는 낮게 나타나는 것으로 분석되었다. 이러한 결과는 도시 내에서 비산먼지에 기반한 안전 거리를 설정하는 데 중요한 기초 자료로 활용될 수 있으며, 측정차량 운영 시 앞차에서 발생하는 배기가스의 영향을 최소화하여 비산 먼지 농도만을 측정할 수 있는 자료로 활용될 수 있다. 본 연구는 배기가스가 도로 비산먼지 농도에 미치는 영향을 실증적으로 분석함으로써, 대기질 개선을 위한 보다 효과적인 정책 수립 에 기여할 것으로 기대된다. 궁극적으로, 도심부 도로 내 도로 비산먼지에 대한 영향을 고려할 때 배기가스에 따른 농도 변화를 이해 함으로써, 향후 도시 환경에서의 지속 가능한 교통 관리와 대기질 개선 전략을 개발하는 데 중요한 기초 자료가 될 것으로 판단된다.

도심지에 시공된 아스팔트 포장은 교통량 증가와 중차량의 가감속으로 인해 포트홀 및 소성변형 등의 파손이 흔히 발생하고 있다. 이러한 아스팔트 포장의 파손을 최소화하기 위해 콘크리트 포장으로 전환하는 공법인 초속경 시멘트 콘크리트 포장 공법과 프리캐스 트 콘크리트 포장 공법이 있으나 고비용으로 인해 널리 적용하기에는 한계가 있는 실정이다. 최근 서울시에서는 신설 중앙버스정류장 에 현장타설 방식으로 연속철근 콘크리트 포장(CRCP)을 시공하였다. 본 연구에서는 인력포설 방식으로 시공한 중앙버스정류장의 CRCP에 대한 공용성을 분석하고자 온도계, 균열유도장치, 철근 변형률계, 콘크리트 변형률계, 변위계, 균열계 등을 포함하는 계측시스 템을 구축하였으며 본 논문에서는 이러한 계측시스템에 대하여 기술한다.

This paper introduces a study on measuring the 3D vibration displacement of plate structure using Digital Image Correlation (DIC) applied to stereo digital continuous camera images. The proposed method is a non-contact 3D displacement measurement method that does not require physical sensors to be attached to the structure, and it has the advantage of simultaneously measuring dynamic displacements at multiple points on the structure. Theoretically, multiple cameras can be used, but in this study, two cameras were used to capture continuous images of the vibrating structure, and the image coordinates of multiple tracking points at arbitrary positions on the structure were measured using correlation matching. Using these image coordinates as input data, the dynamic 3D positions were calculated through Space intersection, successfully determining the 3D dynamic displacements. The measured dynamic displacements were validated for accuracy by comparing them with values measured by laser displacement sensors. And frequencies of measured data were validated by comparing with computational modal analysis by Finite Element Model (FEM).

목적 : 본 연구는 보조공학의 경제성 분석을 국내에 적용하기 위한 방안을 제시하고자, 보조공학의 경제적 및 사회경제적 가치와 측정 도구를 중점적으로 알아보고자 하였다. 연구방법 : 2013년 1월부터 2023년 9월까지, 국외 데이터베이스인 CINAHL, MEDLINE, SCOPUS, Web of science를 이용하여 보조기기 및 서비스의 경제성을 분석한 문헌을 검색하였다. 선정 및 배제 기준에 따라 총 16편의 논문을 최종 선정하였으며, 질적 수준을 평가하였다. 결과 : 경제성 분석에는 사회적, 개인적, 지불자 및 의료 관점이 고려되었으며, 이 중 사회적 관점이 가장 일반적이었다. 연구는 주로 미국과 유럽에서 수행되었으며, 아시아에서는 제한적이었다. 문헌의 질적 수준은 Markov 모델을 사용한 연 구에서 높았으며, ‘우수’ 또는 ‘보통’ 수준이 각각 13편, 3편이었다. 보조공학은 이동, 청각, 정보통신 그리고 기타로 분류 되었으며, 삶의 질을 고려한 문헌은 13편이었고, 주로 사용된 도구는 EQ-5D, HUI, SF-36과 WTP였다. 결론 : 본 연구는 국외 문헌 고찰을 통해 보조공학의 경제성 연구에 기초를 제공한다는 점에서 의의가 있으며, 향후 국내 에서 보조공학의 경제성 분석이 활발히 이루어지길 기대한다.

In this study, data on indication errors within the range of 0 to 10 mm were measured using a dial gauge, which is widely used as a comparative measuring instrument in the field. Using Minitab, a statistical program, measurement conditions were determined during calibration of measuring instruments. Since the P value of the test statistic for the indication error is 0.000 to 0.003, the alternative hypothesis (H1) that no significant difference occurs due to a change in the measurement point at the significance level of 0.05 was adopted.

항만 내 선박과 부두의 사고를 예방하기 위하여 통항 및 접안 안전성 평가를 통하여 안전한 부두가 건설되어 관리하고 있으나, 선 박의 접안 및 계류 과정에서 선박이 부두에 충돌하거나 로프로 인한 인명사고의 발생 등 예측할 수 없는 사고들이 종종 발생한다. 자동계류장 치는 선박의 신속하고 안전한 계류를 위한 자동화된 시스템으로 로봇 매니퓰레이터와 흡착 패드로 구성된 탈/부착 메커니즘을 가지고 있다. 본 논문은 자동계류장치의 흡착 패드의 위치 및 속도제어에 필요한 선체와의 변위 및 속도 측정 시스템을 다룬다. 자동계류장치에 적합한 측 정 시스템을 설계하기 위하여, 본 논문은 우선 센서의 성능 및 실외 환경적 특성 분석을 수행한다. 다음으로 이러한 분석 결과를 토대로 실외 부두환경에서 설치되는 자동계류장치에 적합한 변위 및 속도 측정시스템의 구성 및 설계 방법에 대해 기술한다. 또한 센서의 측정상태 감지 및 속도 추정을 위한 알고리즘을 제시한다. 제안된 방법은 다양한 속도 구간에서의 변위 및 속도 측정 실험을 통해 그 유용성을 검증한다.

Noise is a sound that people don't want. In this study, noise is measured for SR20, a general aviation trainer used in Korea. In addition, noise measurement points are selected at Muan Airport, where most of the domestic trainers fly under the supervision of the Ministry of Land, Infrastructure and Transport, and the measured data are analyzed based on this. We also want to analyze the noise characteristics of SR20 aircraft through frequency analysis of the noise characteristics of SR20 aircraft are unique. We want to use this to understand what type of noise the trainer affects in future studies. this study will improve the reliability of the noise prediction scenario by comparing and analyzing the actual measured and predicted values when using the noise prediction program.

본 연구에서는 형광측정기법을 사용하여 태안반도 인근 8지점의 표층 해수 내 미세플라스틱 정량분포를 조사하였다. 연구결과 미세플라스틱의 검출범위는 0~360.5 particles/l (평균 149.7 ± 46.0 particles/l)로 나타났다. 하지만 해양환경 내 미세플라스틱의 정량분석방법이 표준화되지 않아 타 연구결과와 직접비교 하는 것이 불가능한 상황이다. 본 연구결과 검출된 미세플라스 틱을 크기별로 분류하면 < 50 μm 크기가 우점하지만, St. 3의 경우 > 500 μm이 25.6%를 차 지하여 지역별로 우점하는 미세플라스틱의 크기에 차이가 나타난다. 또한 채집지역, 저질의 종 류, 검출되는 플라스틱 크기에 따른 미세플라스틱의 검출량 비교에도 뚜렷한 상관관계를 가지 는 요인을 확인할 수 없었다. 이는 플라스틱의 재질에 따른 물리 · 화학적 특성, 해양의 동적 조건(해류, 바람, 파도, 조류 등), 지질학적 특성(지형, 경사 등), 연안 생물을 포함한 저질의 구성 및 특성, 상호작용, 인간활동(어업, 개발, 관광 등), 기상조건(홍수, 강우 등)과 같은 다양한 요인 이 미세플라스틱의 거동에 영향을 주기 때문이다. 그러므로 향후 정량분석방법 표준화 및 환 경요인에 대한 분석이 수반된 미세플라스틱 모니터링 기초연구가 필요한 상황이다.

This paper reports the results of an experimental examination using X-rays to test annealing materials for lapped bearing steel (STB2), to confirm the validity of the weighted averaging analysis method. The distribution behavior for the sin diagram and the presence or absence of differences in the peak method, half-value breadth method, and centroid method were investigated. When lapping the annealed bearing steel (STB2) material, a residual stress state with a non-directional steep gradient appeared in the surface layer, and it was found that the weighted averaging analysis method was effective. If there is a steep stress gradient, the sin diagram is curved and the diffraction intensity distribution curve becomes asymmetric, resulting in a difference between the peak method, half-value breadth method, and centroid method. This phenomenon was evident when the stress gradient was more than 2~3 kg/mm2/μm. In this case, if the position of the diffraction line is determined using the centroid method and the weighted averaging analysis method is applied, the stress value on the surface and the stress gradient under the surface can be obtained more accurately. When the stress gradient becomes a problem, since the curvature of the sin diagram appears clearly in the region of sin > 0.5, it is necessary to increase the inclination angle  as much as possible. In the case of a lapping layer, a more accurate value can be obtained by considering  in the weighted averaging analysis method. In an isotropic biaxial residual stress state, the presence or absence of  can be determined as the presence or absence of strain for sin≈0.4.

Microclimate analysis was conducted through actual measurement according to land use status in urban, and CFD analysis was conducted to analyze and predict the microclimate characteristics of urban, and compared and analyzed with the actual measurement results. It was measured in high-rise areas and parks, and the temperature of the park area was 0.4 to 0.6℃ lower, and the relative humidity was 1.0 to 3.0% higher. The correlation coefficient was obtained by comparing the results of the computational fluid analysis with the results of the computational fluid analysis at the actual location located within the CFD analysis area for validation. The seasonal correlation coefficients are all higher than 0.8, so it is judged that they can be applied to microclimate analysis in urban area. The computational fluid analysis was divided into three areas (low-rise, low and high-rise, and high-rise) centered on the A2 point. On average, the low-rise area was 0.1 to 0.4% higher than the high-rise area. In the low and high-rise area and high-rise area, the pith of buildings are wide, so the airflow is smooth, so it is judged that the temperature is relatively low.

Noise is a sound that humans do not want. In this study, noise is measured for C172, the most frequently used general aviation trainer in Korea and abroad. In addition, in this study, noise measurement points are selected for Muan Airport, where most of the domestic training aircraft fly under the supervision of the Ministry of Land, Infrastructure and Transport. Based on this, the measured data is scaled and analyzed. In addition, we intend to analyze what characteristics C172 aircraft have unique through frequency analysis of noise of C172. Through this, it is intended to understand what type of noise training aircraft affect in future studies.

The purpose of this study is to develop a pH measurement system capable of measuring the acidity of saliva to check the change in pH level in saliva during driving and to detect whether fatigue is affected. When the pH level is checked at rest and operation, and oxygen concentration is supplied additionally, it will be verified whether the fatigue is reduced. It is reported that the pH level in saliva is divided into stages from 0 to 14, and the lower the value based on step 7, the higher the fatigue, and the lower the fatigue. In particular, in enclosed vehicles, drowsiness and fatigue due to increased carbon dioxide have increased, leading to a major cause of traffic accidents. Therefore, fatigue may be detected in advance by analyzing fatigue through a change in pH level by supplying oxygen during operation. The electromotive force generated by the existing itself is a level of several mV to develop a pH measurement system, so it is developed by expanding it to a range that can be measured using a readout circuit. In the experiment, 13 male experimenters in their 20s measured pH levels in resting and driving conditions. After 20 minutes of rest, the process of inhaling oxygen for 20 minutes was repeated three times. The oxygen concentration used in the experiment was 21% oxygen and 30% oxygen concentration in the atmospheric state, and in the oxygen supply method, a triangular flask was directly connected to the subject’s nose and then oxygen was supplied. As a result of collecting and analyzing saliva after rest and operation, it was confirmed that the pH level tended to decrease in the operating state. In addition, as a result of increasing the pH level when the oxygen concentration is 30% more than 21%, it is confirmed that fatigue tends to decrease as the oxygen concentration increases. Therefore, it was possible to confirm a significant change in fatigue by analyzing the pH level of saliva through this pH measurement system. This study can be used as a fatigue test in various environments through simple pH measurement.

This study was evaluated based on the items of KS B 6389. The study on the calculation of angular error and measurement uncertainty of HRc hardness measurement using statistical techniques using Rockwell measurement specimens with different hardness values ​​was analyzed, and the results were derived according to the change in the angle of the indenter part of the hardness tester and the specimen. As a result of the experiment, the test statistic P values ​​for angle changes such as 0°, 1°, and 2° were all 0.000 using the HRc 30 and 40 measurement specimens, so it was confirmed through the experiment that a significant difference occurred between them. In addition, the extended uncertainty value was calculated as 0.612 at the 95.45% confidence level, and the fact that the hardness test value came out smaller than the existing test value as the inclination angle increased was verified through experiments.

Research is being actively conducted on the continuous thin plate casting method, which is used to manufacture magnesium alloy plate for plastic processing. This study applied a heat transfer solidification analysis method to the melt drag process. The heat transfer coefficient between the molten magnesium alloy metal and the roll in the thin plate manufacturing process using the melt drag method has not been clearly established until now, and the results were used to determine the temperature change. The estimated heat transfer coefficient for a roll speed of 30 m/min was 1.33 × 105 W/m2·K, which was very large compared to the heat transfer coefficient used in the solidification analysis of general aluminum castings. The heat transfer coefficient between the molten metal and the roll estimated in the range of the roll speed of 5 to 90 m/min was 1.42 × 105 to 8.95 × 104 W/m2·K. The cooling rate was calculated using a method based on the results of deriving the temperature change of the molten metal and the roll, using the estimated heat transfer coefficient. The DAS was estimated from the relationship between the cooling rate and DAS, and compared with the experimental value. When the magnesium alloy is manufactured by the melt drag method, the cooling rate of the thin plate is in the range of about 1.4 × 103 to 1.0 × 104 K/s.

Failure to comply with the performance test requirements for the centrifugal pumps at power plants often results in performance dissatisfaction as a result of field tests. This study proposed a method of reducing the uncertainty of the field test results by evaluating the systematic error in the measurement system caused by failure to follow the test requirements using the computational fluid dynamics(CFD) technique. As a result of the evaluation of the systematic error and reflecting it in the performance test data, it was confirmed that the error occurred at a constant rate with respect to the flowrate and that the pump, which showed a difference in performance actually had the same performance.

The study was aimed to investigate the operational meal costs by kindergarten size in Seoul and to analyze recognition for optimal meal prices. A survey (31.6% recovery rate) was conducted on all kindergartens (779 kindergartens) in Seoul on April 2021 using descriptive analysis, t-test, and dispersion method. A price sensitivity measurement (psm) method was used to determine optimal meal prices. Result showed an average food cost for kindergartens of 2,647 won, an average labor cost of 605 won, an average operating cost of 146 won, and the total meal cost of 3,506 won. Total meal cost decreased with increasing kindergarten size (p<0.001). On the other hand, kindergartens with more students decreased the ratio of food cost to total meal cost, and operating cost and labor costs (p<0.001) increased. The optimal price of kindergarten operators' meal cost (OPP) was KRW 3,673. Furthermore, the analysis showed the sensitivity of operators' meal costs to kindergarten size was insignificant.

In this study, using a 100mm gauge block in a contact-type three-dimensional measuring machine surface plate, an NPL-type angle measurement, and a steel ruler, the specimen was measured at 0°, 5°, 10°, 20°, 30°, and 40° along the X and Y axes. After setting the measurement conditions, the average value and standard deviation were confirmed by repeating measurements for each yield 10 times. After checking the statistical test value (P) through ANOVA, the correlation between the angle change and the error was checked.

As modern society has emerged and developed, the subway has established itself as a representative means of transportation in the city due to its speed, accuracy, and accessibility. According to the Indoor Air Quality Management Act, underground stations have established and managed the maintenance and recommendation standards for PM10, PM2.5, CO2, CO, HCHO, NO2, Rn, VOCs However, th the standards for airborne mold has not been applied for subway stations even though management for the health effect of exposure to mold is necessay. In this study, the correlation with major contributing factors was analyzed by measuring the concentration of airborne molds in the indoor air of underground stations and through literature research. It was confirmed that there was a correlation between the concentration of airborne molds in subway stations and the major contributing factors. As a result of the analysis, it was found that the concentration of airborne molds became higher as the location of the platform became deeper underground, during periods of congestion, and especially in summer. There was no significant correlation with the year of construction. Our findings indicate that appropriate management measures should be devised in response to such contributing factors.

Appropriateness of the minimum detectable activity in the analysis of gamma radionuclides is very important. This is reason determine the time factor among the conditions of the analysis when it is rationally determined has the advantage that radioactivity analysis can be performed accurately and quickly. In this study, 100 mL of an unknown sample was diluted in Marinelli Beaker 1L to obtain, review data on gamma radiation analysis results and minimum detectable activity for each measurement time. The measurement was used High Purity Germanium detector, target nuclides are Co-57, Co-58, Y-88 and Cs-137. Since the radioactivity analysis sample will be expected to be the waste subject to selfdisposal or less during the radioactive waste classification, the minimum detectable activity standard was set based on the detection of less than the permissible activity for self-disposal for each nuclide. The measurement methods were measured by classifying it into seven categories: 1000 seconds, 3600 seconds, 10000 seconds, 30000 seconds, 80000 seconds, 100000 seconds, and 150000 seconds. The radioactivity from this measurement are Co-57 2.89 Bq·g−1, Co-58 0.19 Bq·g−1, Y-88 0.20 Bq·g−1, Cs-137 0.15 Bq·g−1, the measurement results under all conditions were similar. On the other hand, the minimum detectable activity showed values above the allowable activity for self-disposal in not but Co-58 at 1000 and 3600 seconds. Only after taking the measurement time of 10000 seconds, the result was derived Co-57 0.0095 Bq·g−1, Co-58 0.0068 Bq·g−1, Y-88 0.0052 Bq·g−1, Cs-137 0.0062 Bq·g−1, which was confirmed to less than the allowable activity for self-disposal by nuclide. Reasonably determining the measurement time in gamma radionuclide analysis is a very important issue in terms of economy of time and accuracy of measurement. Although this study cannot be said to be able to determine a reasonable measurement time for all gamma radionuclide analysis, it is hoped that research on various samples will be made to contribute to the efficient measurement of gamma radioactivity.