• 조명전기설비학회논문지
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• 제29권5호
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• pp.26-33
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• 2015

Secondary optical system designed for LED bulb which emits light in all directions was simulated with Energy Star standards. Components of the optical system were LED light source, the cover of the LED bulb and reflector which is to confirm the diffuser plate and LightTools software was used to design the illumination optics. The main points of the secondary optical system design are the location of the LED light source, the shape of the LED bulb cover, the location of the reflection plate, and the scattering properties of the diffusing plate. Mechanism of the LED bulb is that the light emitted from the light source move on to the backward after reflected by the coated light cover from the inside and then the reflected light is scattered by the diffuser plate. The LED bulb was designed to satisfy the standard light distribution and color specifications of the Energy Star(IES LM-79-08).

• 조명전기설비학회논문지
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• 제30권1호
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• pp.28-37
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• 2016

Fault locating is an important element to minimize the damage of power system. The computation error of fault locator may occur by the influence of the DC offset component during phasor extraction. In order to minimize the bad effects of DC offset component, this paper presents an improved fault location algorithm based on a DC offset removal filter for short fault in a double circuit transmission line. We have modeled a 154kV double circuit transmission line by the ATP software to demonstrate the effectiveness of the proposed fault locating algorithm. The line to line short faults were simulated and then collected simulation data was used. It can be seen that the error rate of fault locating estimation by the proposed algorithm decreases than the error rate of fault locating estimation by conventional algorithm.

• 조명전기설비학회논문지
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• 제28권1호
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• pp.114-122
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• 2014

This paper describes a study of the design conditions of a planar surface dielectric barrier discharge (DBD) reactors for generating negative air ions. The capacity of negative air ion generated by the surface DBD reactor is affected by the shape, area ratio and the location of the discharge and induction electrodes of it. To study the optimal design conditions of DBD reactors, the electrodes printed on the substrate of a PCB board is utilized to conduct kind of experiments: the distance of the each electrode along with the X-Y axis, the area ratio of the discharge electrode to induction electrode, and the symmetrical and asymmetrical location of two electrodes. The ion generation capacity is inverse proportional to the gap increases along with X-Y axis. And the optimum ion concentration generated by the ionizer was inspected when the electrodes area ratio was 3 and 5 times of the symmetrical and asymmetrical experimental condition respectively.

• 센서학회지
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• 제30권2호
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• pp.105-108
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• 2021

Detection and localization of partial discharge are considered critical techniques for estimating the lifetimes of power cables. High-frequency current transformers (HFCTs) are commonly used for the detection of partial discharge in high-voltage alternating current (HVAC) power cables; however, their applicability is compromised by the limitations of the installation locations. HFCTs are typically installed in cable terminals or insulation joint boxes because HVACs induce strong time-varying magnetic fields around the cables, saturating the ferromagnetic materials in the HFCTs. Therefore, partial discharges near the installation locations can be detected. In this study, the feasibility of partial discharge detection using a HFCT was investigated for high-voltage direct current (HVDC) cables. We demonstrated that the HFCT could be installed at any location in the HVDC power cable to monitor partial discharge along the entire cable length. Furthermore, we showed that the HFCT could detect the location of partial discharge with high accuracy.

• 대한교통학회지
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• 제28권2호
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• pp.123-133
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• 2010

현재 국내의 횡단보도 설치 관련 기준은 육교 지하차도 및 다른 횡단보도로부터 200m 이내는 중복설치를 금하고 있다. 만약 횡단보도를 설치하고자 할 때는 지방경찰청장이 타당성을 검토하여 설치하도록 규정하고 있으나, 횡단보도의 설치형태와 세부기준은 미흡한 실정이다. 본 연구에서는 Mid-Block상의 버스정류장 배치형태(접근부, 유출부)에 따른 각각의 사고예측모형을 개발하였으며, 사고건수와 사고심각도를 종속변수, 버스정류장과 횡단보도 이격거리, 교통량, 보행량을 독립변수로 하는 포아송 회귀모형식을 개발하였다. 유출부모형의 경우 연간 교통사고 심각도는 버스정류장과 횡단보도간의 이격거리, 교통량, 보행량의 증가에 따라 사고와 양(+)의 관계로 증가하고, 접근부 모형의 경우는 교통량, 보행량의 증가에 따라 사고와 양(+)의 관계로 증가하지만 버스정류장과 횡단보도간의 이격거리는 음(-)의 관계로 분석되었다. 따라서, 교통사고를 최소화할 수 있는 버스정류장과 횡단보도 이격거리는 횡단보도 접근형과 유출형의 혼합형인 횡단보도의 경우는 이격거리 65m일 때 최적의 배치형태로 분석되었으며, 유출부와 접근부 사고 모형식을 통해서 얻은 최적 이격거리가 60m~70m로 나타났다.

• 산업기술연구
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• 제28권A호
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• pp.97-104
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• 2008

Recently, interests on positioning system for location-based services have been significantly increased. Many indoor environment systems using fingerprint scheme have been designed to take more accuracy of positioning, but they are inefficient in adapting to change of environments. In this paper, we focus on a client-based positioning system over WLAN for decreasing installation cost and adapting to change of environments. In the proposed system, APs with stable RSSI are selected as base APs independently for each reference point. Experimental results show that proposed system expands service area approximately 20% much than traditional systems using K-NN algorithm and needs only 20% modification process to fingerprint data compare with traditional systems whenever environment conditions are changed.

• Journal of Multimedia Information System
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• 제6권4호
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• pp.265-270
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• 2019

The technology to locate an individual has enabled various services, its utilization has increased. There were constraints such as the use of separate expensive equipment or the installation of specific devices on a facility, with most of the location technology studies focusing on the accuracy of location verification. These constraints can result in accuracy within a few tens of centimeters, but they are not technology that can be applied to a user's location in real-time in daily life. Therefore, this paper aims to track the locations of smartphones only using the basic components of smartphones. Based on smartphone sensor data, localization accuracy that can be used for verification of the users' locations is aimed at. Accelerometers, Wifi radio maps, and GPS sensor information are utilized to implement it. In forging the radio map, signal maps were built at each vertex based on the graph data structure This approach reduces traditional map-building efforts at the offline phase. Accelerometer data were made to determine the user's moving status, and the collected sensor data were fused using particle filters. Experiments have shown that the average user's location error is about 3.7 meters, which makes it reasonable for providing location-based services in everyday life.

• 한국융합학회논문지
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• 제10권12호
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• pp.251-255
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• 2019

QR 코드는 스티커 형태로 인쇄되어 설치비용이 저가로 위치 인식하기 위한 천장이나 벽면에 인공지표를 붙이는 위치 인식 방식과 비전으로 위치 인식을 하는 방식에 비교하여 위치 인식 정확도 면이나 설치비용 면에서 많은 장점을 보유하고 있어 모든 산업에 전반적으로 적용 가능한 로봇을 만든다. 본 연구에서는 정사각형 2차원 바코드를 통해 오차범위는 3 mm 이내 로봇에 적용하는 기술로 정확도가 뛰어나 정확한 위치제어가 가능한 로봇을 만들 수 있음을 보여주며, 특히 여러 공학 기술이 합쳐진 융합연구는 QR 코드 인식 실내이동 로봇제어 연구의 시스템 구성을 중심으로 기술한 것이다.

• 건축역사연구
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• 제23권2호
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• pp.39-52
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• 2014

This study researched changes over time regarding the location and spatial characteristics of modern meteorological stations, and examined the characteristics of modern meteorological station construction using the location and spatial characteristics of the Busan Meteorological Station. First, meteorological stations were located in port areas, and then moved to high altitude areas for stable meteorological observation beginning in the transition phase. Here, office buildings and residences were joined, but were separated due to the increase in functions from the stabilization phase. Second, as for spatial composition, in the establishment phase, existing buildings were used, and the scale of newly constructed buildings differed according to time and area. However, after the Japan-Korea Annexation, with increased funds and increased observation equipment, floor plans subdivided by function started to appear. In the stabilization phase, space was subdivided with redundancy due to the increase in functions. In the wartime transition phase, '一' shaped floor plans with redundancy became the norm. Meanwhile, the location of the maritime customs where the first meteorological observations took place after the opening of the ports, and the location and construction of the Busan Temporary Observatory built in the meteorological observation transition phase (1905) were investigated. Also, through the investigation of the Busan Meteorological Observatory, newly constructed before 1934, the location and spatial characteristics of modern era meteorological observatories were studied.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2011년도 추계학술대회
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• pp.507-510
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• 2011

최근 스마트 폰과 같은 무선 모바일 기기 사용량의 증가 때문에 위치 기반 서비스(LBS : Location Based Service)에 대한 연구가 활발히 증가하고 있다. 실외 위치 측위는 무선 모바일 기기에 내장된 GPS를 이용할 수 있다. 하지만 일반 건물보다 규모가 큰 대형 크루즈선의 실내 같은 곳에서는 GPS 사용이 불가능하므로 실내 환경에 적합한 위치 측위 방식을 고려하여야 한다. Wi-Fi(Wireless Fidelity)는 실내의 여러 곳에 설치 되어 있어서 추가로 Wi-Fi의 설치과정을 거치지 않아도 되고, 다른 무선 센서 기기와 비교하면 비교적 싼 가격을 가진다. 본 논문에서는 Wi-Fi의 신호를 이용하여 실내에서 의미 있는 공간을 인지하는 베이지안 알고리즘을 소개한다.