• 환경영향평가
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• 제15권4호
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• pp.271-277
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• 2006

In this study, we investigated the applicable plan of GIS on the environmental impact assessment of 60 Hz Powerline. So we assessed distance data based on calculations by use of 2D and 3D Geographical information systems(GIS) and distance data based on measurements on 1: 5000 maps accord with on site distance measurements to use input data for calculating magnetic field. One hundred eight of the on site measured addresses were selected from residences. The data were achieved by measuring the distance between residence and power line on maps with scales of 1: 5000. The digital map was obtained from National Geographic Information Institute with scales of 1: 5000, and we made 2D and 3D map. Correlation analyses were performed for statistical analyses. For the 3D GIS versus on site comparison of different exposure categories, 70 of 108 measurements were assigned to the correct category. Similarly for 2D GIS versus on site comparison, 71 of 108 were correctly categorized. When comparing map measurement with on site measurement, 62 of 108 were correctly categorized. When the correlation analysis was performed, best correlation was found between 3D GIS and on site measurements with r = 0.84947 (p<0.0001). The correlation between map and on site measurement yielded an r of 0.76517 (p<0.0001). Since the GIS measurements and map measurement were made from the center point in the building and the on site measurements had to be made from the closest wall on the building, this might introduce and additional error in urban areas. The difference between 2D and 3D calculations were resulted from the height of buildings.

• 한국융합학회논문지
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• 제12권7호
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• pp.53-60
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• 2021

LOD-기반 추천 시스템은 보통 DBpedia와 같은 LOD 데이터세트 내에서 사용가능한 데이터를 활용하여 최종 사용자에게 영화, 책, 음악과 같은 아이템을 추천한다. 이러한 시스템은 링크드 데이터 리소스 쌍 간의 일치 정도를 측정하는 의미 유사도 알고리즘을 사용한다. 이 논문에서는 LOD 그래프의 링크에 사용자 평가 등급을 변환한 가중치를 할당하여 LOD-기반 추천 시스템에서 의미 거리를 측정하는 새로운 접근방식을 제안했다. 이 논문에서 제안된 의미 거리 측정 모델은 가중치 계산을 통해 그래프가 사용자에게 개인화되는 처리 단계와 이러한 가중치를 LDSD에 적용하는 방법을 기반으로 한다. 실험 결과는 다른 유사한 방법들과 비교하여 제안된 방법이 더 높은 정확도를 보였으며, 추천 시스템의 의미 거리 측정의 범위를 넓혀서 유사도 향상에 기여하였다. 향후 연구로는 다른 방법의 LOD-기반 유사도 측정을 사용하여 모델에 미치는 영향을 분석하는 것을 목표로 한다.

• 한국해양공학회지
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• 제36권5호
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• pp.340-352
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• 2022

This article presents a modeling method for the uncorrelated measurement error of the ultra-short baseline (USBL) acoustic positioning system for aiding navigation of underwater vehicles. The Mahalanobis distance (MD) and principal component analysis are applied to decorrelate the errors of USBL measurements, which are correlated in the x- and y-directions and vary according to the relative direction and distance between a reference station and the underwater vehicles. The proposed method can decouple the radial-direction error and angular direction error from each USBL measurement, where the former and latter are independent and dependent, respectively, of the distance between the reference station and the vehicle. With the decorrelation of the USBL errors along the trajectory of the vehicles in every time step, the proposed method can reduce the threshold of the outlier decision level. To demonstrate the effectiveness of the proposed method, simulation studies were performed with motion data obtained from a field experiment involving an autonomous underwater vehicle and USBL signals generated numerically by matching the specifications of a specific USBL with the data of a global positioning system. The simulations indicated that the navigation system is more robust in rejecting outliers of the USBL measurements than conventional ones. In addition, it was shown that the erroneous estimation of the navigation system after a long USBL blackout can converge to the true states using the MD of the USBL measurements. The navigation systems using the uncorrelated error model of the USBL, therefore, can effectively eliminate USBL outliers without loss of uncontaminated signals.

• 웰빙융합연구
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• 제4권3호
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• pp.23-33
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• 2021

Purpose: In the course of the domestic environmental impact assessment, the current status survey was improperly conducted, and the issue of false and inaccurate environmental impact assessment reports has been raised several times recently through media reports. Research design, data and methodology: There is a continuous demand for improvement measures for the current status measurement method, such as having difficulties in securing a normal measurement date in consideration of equipment operation and rainfall days in the field. Results: In addition, in order to grasp the general air quality status of the evaluation target area, it is necessary to check the various current status concentrations by season and time series per year. However, there is a problem that is currently being carried out based on limited results such as measurement for 1 day or 3 days. Conclusions: Therefore, in this study, based on the national atmospheric measurement network, an inverse distance weighted (IDW) interpolation method was applied to calculate the current state concentration. This study suggested a method to use it in preparing the air quality item in the environmental impact assessment report.

• International Journal of Computer Science & Network Security
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• 제21권7호
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• pp.17-34
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• 2021

This study aimed to examine the Factor Structure of the teacher satisfaction scale (TSS) with distance education during the Covid-19 pandemic, as well as affirming the (Factorial Invariance) according to gender variable. It also aimed at identifying the degree of satisfaction according to some demographic variables of the sample. The study population consisted of all teachers in public education and faculty members in higher education in the Kingdom of Saudi Arabia. The (TSS) was applied to a random sample representing the study population consisting of (2399) respondents. The results of the study showed that the scale consists of five main factors, with a reliability value of (0.94). The scale also showed a high degree of construct validity through fit indices of the confirmatory factor analysis. The results have shown a gradual consistency of the measure's invariance that reaches the third level (Scalar-invariance) of the Measurement Invariance across the gender variable. The results also showed that the average response of the study sample on the scale reached (3.74) with a degree of satisfaction, as there are no statistically significant differences between the averages of the study sample responses with respect to the gender variable. While there were statistically significant differences in the averages with respect to the variable of the educational level in favor of the middle school and statistically significant differences in the averages attributed to the years of experience variable in favor of those whose experience is less than (5) years.

• 대한전자공학회논문지
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• 제24권5호
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• pp.762-768
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• 1987

The capacitive transducers, which are used of the principle of capacitance changes by means of the variation of distance between electrodes, are usually utilized for measurement of small displacements. But the measurement ranges of this method are limited. In this study, the measurement ranges are extended by using the variation method of the surface area of electrodes. Thus the capacitive transducer and signal conditioner, which are having the capability of measurement range of 25mm and resolution of 0.1\ulcorner, have developed, and its environmental characteristics are also tested.

• 조명전기설비학회논문지
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• 제18권1호
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• pp.137-145
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• 2004

본 논문은 평행식 스테레오 영상감시 시스템을 이용하여 3차원 공간에서 다중 이동물체를 검출하고, 카메라에서 이동 물체까지의 거리를 측정하는 알고리즘을 제안하였다. 스테레오 영상감시 시스템의 좌, 우측 영상을 입력을 받아 적응형 임계값과 화소귀납 알고리즘(PRA, pixel recursive algorithm)을 사용하여 다중 이동물체 영역을 추출하였다. 그리고 각각의 물체영역을 윈도우 마스크로 검출하고, 다중 이동물체 각각의 위치좌표와 스테레오 시차를 구하였다. 이 시차와 스테레오 비전 시스템의 특성 및 삼각 함수를 이용하여 다중 이동물체의 거리를 측정하였다. 실험결과 거리측정 오차도 7.28％이내에 존재하였으며, 따라서 제안한 알고리즘을 이용하여 시스템을 구현할 경우 스테레오 방범 시스템, 자율 이동로봇 및 스테레오 원격제어 시스템 등에 응용될 수 있을 것이다.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2004년도 하계종합학술대회 논문집(1)
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• pp.209-212
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• 2004

This paper has been studied the impact of the distance between the signal source and the antenna under test on the antenna measurements such as gain and pattern (Phase). The concept and principles of the far-field in the antenna measurement are reviewed at first. The analysis on the impact has been focused on the 11 m parabola antenna system which will be used in the ground telemetry station for tracking and receiving the S-band ($2200\~2400MHz$) signal of KSLV-I. Also, the impact of the distance on the tracking performance of the antenna system has been analyzed.

• 대한기계학회논문집A
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• 제29권12권
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• pp.1638-1644
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• 2005

This paper suggests fur the study on a fluid velocity measuring system using ultrasonic transducer. In general, the time difference method to measure the distance between transducers has been known. In this paper, the practical technology for manufacturing ultrasonic flow meter system is studied using the time difference method. The ultrasonic transducer was designed and manufactured. The transmission and receiving algorithm for ultrasonic signal was studied. The ultrasonic flow measuring system was experimented in laboratory using a water reservoir for verifying the distance measuring accuracy. Finally, it was tested in flow calibration laboratory for the velocity measuring performance. The system, designed in this study, showed 0.3 mm resolution in distance measurement. For precise flow measurement, a high speed triggering algorithm is required for ultrasonic signal receiving.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2004년도 추계학술대회 논문집
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• pp.106-109
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• 2004

In this project, we have developed the eye-safe LRF system of 1.54 ${\mu}{\textrm}{m}$ wavelength using OPO. The maximum measured distance was 3.7km in outdoor experiment. We used Nd：YAG (1064nm) as a laser medium. It was applied BBO to construct the system. We also developed a time-counter for the range finder using a method of TOF (time of flight). The counter-clock used at the time counter was 320MHz making resolution within $\pm$1m. Start and stop signals were detected by two channel systems using PIN and APD. The LRF's repetition rate was 4 times per minute. The energy was measured to be over 9mJ. And, pulse-duration was 23ns. Resolution was $\pm$2m at the distance measurement using a target.