• 조명전기설비학회논문지
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• 제27권12호
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• pp.38-43
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• 2013

In this paper, the location measurement method for the reliable location data using ultrasonic sensors is proposed for the dimming control of the LED flat lamp. The measurement errors depending on the reflection angle of the object have to be considered to obtain the reliable location data in the ultrasonic sensors. In the experiment, the cause of the measurement errors depending on reflection angle is analyzed and velocity change of ultrasonic wave depending on reflection angle is measured. And the location measurement method depending on velocity change of ultrasonic wave is proposed. From the results, the average absolute deviation of the x-coordinates was 1.47cm when the location measurement method was considered, and it was closer to the true values than the average absolute deviation of the x-coordinates which was 5.89cm without regard to the reflection angle.

• 상하수도학회지
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• 제33권5호
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• pp.389-394
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• 2019

In order to determine the location of average concentration and distribution status of dissolved oxygen in the rectangular aeration tank of the sewage treatment plant was analyzed and the difference of dissolved oxygen concentration was remarkable at each location. Compared with the computational fluid dynamics analysis, it was found that the results were consistent with the measurement results by showing the difference of dissolved oxygen concentration between the locations. Based on the measured data, the representative location of dissolved oxygen in aeration tank was selected by using statistical analysis method and the representative location was expressed in three-dimensional coordinates(LWH : 25%, 50%, 33%) from flow direction and left wall. Also the difference between the dissolved oxygen concentration at the actual measurement location and the average concentration value of the entire aeration tank was founded, and the equations for calibrating the automatic measurement data considering the actual measurement location were calculated.

• 한국경영과학회:학술대회논문집
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• 대한산업공학회/한국경영과학회 2004년도 춘계공동학술대회 논문집
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• pp.119-126
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• 2004

Location management is very important issue in wireless communication system to trace mobile users' exact location. In this study, we propose a dynamic location area management scheme which determines the size of dynamic location area considering each user's characteristic. In determining the optimal location area size, we consider the measurement data as well as the historical data, which contains call arrival rate and average speed of each mobile user. In this mixture of data, the weight of historical data is derived by linear searching method which guarantees the minimal cost of location management. We also introduce the regularity index which can be calculated by using the autocorrelation of historical data itself. Statistical validation shows that the regularity index is the same as the weight of measurement data. As a result, the regularity index is utilized to incorporate the historical data into the measurement data. By applying the proposed scheme, the location management cost is shown to decrease. Numerical examples illustrate such an aspect of the proposed scheme.

• 산업공학
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• 제18권4호
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• pp.382-389
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• 2005

Location management is very important issue in wireless communication system to trace mobile users' exact location. In this study, we propose a dynamic location area management scheme which determines the size of dynamic location area considering each user's characteristics. In determining the optimal location area size, we consider the measurement data as well as the historical data, which contains call arrival rate and average speed of each mobile user. In this mixture of data, the weight of historical data is derived by linear searching method which guarantees the minimal cost of location management. We also introduce the regularity index which can be calculated by using the autocorrelation of historical data itself. Statistical validation shows that the regularity index is the same as the weight of measurement data. As a result, the regularity index is utilized to incorporate the historical data into the measurement data. By applying the proposed scheme, the location management cost is shown to decrease. Numerical examples illustrate such an aspect of the proposed scheme.

• 한국환경보건학회지
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• 제42권5호
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• pp.314-323
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• 2016

Objectives: Time location data are critical for accurately estimating personal exposures. This review papers summarized various measurement methods of time location pattern for air pollution exposure assessment. Methods: Forty manuscripts (papers, books and reports) were reviewed to comprehensively describe time location measurement methods. Results: This review included traditional methods such as time activity diary, questionnaire, observation, focus group and newly developed technical methods including global positioning system, web, radio frequency identification and ultrasound detection. Some research applied a combination of methods. Conclusion: Although various methods have been used to collect time location data, further development of accurate measurement methods for time location data is needed.

• 한국안전학회지
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• 제32권3호
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• pp.41-47
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• 2017

Recent studies have shown that there are various systems which can be used to monitor hazardous area in a debris flow location, but lack of methodological research on the exact location where each instrument should be installed has hindered the success of this systems. The objective of this study is to suggest the measurement system for monitoring debris-flow and propose the effective method to determine location of measurement system. Previously studied, from 1991 to 2015, were referred and the applied ratio of every instrument was investigated. The measurement information was divided into 8 categories including rainfall, debris-flow velocity, displacement, fluid pore pressure, ground vibration, image processing, impact force and peak flow depth. The result of this study revealed that the most applied instruments to be rain gauge and geophone for measuring average rainfall and ground vibration respectively. The Analytic Hierarchical Process (AHP) method was selected to determine installation location of instrument and the weighting factors were estimated through fine content, soil thickness, porosity, shear strength, elastic modulus, hydraulic conductivity and saturation. The soil thickness shows highest weights and the fine content relatively demonstrates lowest weights. The score of each position can be calculated through the weighting factors and the lowest score position can be judged as the weak point. The weak point denotes the easily affecting area and thus, the point is suitable for installing the measurement system. This study suggests a better method for safely managing the debris-flow through a precise location for installing measurement system.

• 제어로봇시스템학회논문지
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• 제16권2호
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• pp.158-163
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• 2010

In this paper, we propose the location measurement algorithm of unknown tag based on RFID (Radio-Frequency IDentification) by using RSSI (Received Signal Strength Indication) and TDOA (Time Difference of Arrival) and extended Kalman filter in smart space. To do this, first, we recognize the location of unknown tag by using the RSSI and TDOA recognition methods. Second, we set the coordinate of the tag location measured by using trilateration and SX algorithm. But the tag location data measured by this method are included complex environmental error. So, we use the extended Kalman filter in order to revise error data of the tag location. Finally, we validate the applicability of the proposed method though the simulation in a complex environment.

• 정보처리학회논문지A
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• 제19A권2호
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• pp.85-92
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• 2012

본 논문에서는 다수의 고속 이동체들의 위치를 측정할 수 있는 확장성 있는 실시간 위치 측정 시스템을 제안한다. 제안된 시스템에서는 위치 서비스가 필요한 영역을 확장 시 기본 단위인 매크로셀이라고 불리는 정사각형의 격자들로 나누고, 한 매크로셀은 $N{\times}N$ 개의 마이크로셀로 나눈다. 마이크로셀의 각 꼭짓점에는 위치 기준 노드가 중앙에는 중재 노드가 설치된다. 위치를 측정하고자 하는 이동체는 우선 중재 노드와의 통신을 통하여 위치 측정을 위한 허가를 받아야 한다. 그러므로 한 마이크로셀내에서는 오직 허가된 하나의 이동 노드만이 위치 기준 노드들과 연속적으로 통신하면서 자신의 위치를 계산할 수 있다. 제안된 시스템의 성능을 측정하기 위하여, 제안된 시스템을 모델링하고 시뮬레이션 하였다. 시뮬레이션 결과 제안된 시스템은 위치 측정을 위한 통신 시간이 짧고 고속 이동체의 위치를 계산할 경우 오차가 적은 것으로 나타났다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1991년도 추계학술대회 논문집 학회본부
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• pp.415-418
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• 1991

This paper described an instrument for the detection and geometric location of partial discharge(PD) sources in oil transformer. This instrument measures electric current pulse and ultrasonic pulse simultaneously in order to determine the geometric location of PD in transformer. Laboratory experiment systems are made for detection and location of PD in oil transformer. It was observed that there are effects of the barrier, such as insulation papers, silicon steel plate and actual transformer with location and detection of PD in model transformer. Through the laboratory actual test, it was clarified that this measurement device could be used satisfactorily for location of pd in oil transformer.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2005년도 Proceedings of ISRS 2005
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• pp.659-662
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• 2005

Recently, the need for LBS (Location Based Services) is increasing with the rapid growth of the location measurement units, mobile devices, and communication technologies. Especially, wireless carriers are concentrating on LBS since it is regarded as so-called 'killer application' among wireless data services. Although LBS give us convenience and useful information, its use also raises privacy issues. There are quite possibilities that the people's locations are tracked by location measurement units while people do not recognize the existence of the units. To protect a person's location information, lawful and technical aspects should be considered. In this paper, we explain issues, regulations, standards, and platforms related to the protection of the location information. Finally, we suggest the architecture of a platform complying with the regulations and standards. It considers various issues not covered in other studies.