• KSII Transactions on Internet and Information Systems (TIIS)
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• 제6권7호
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• pp.1815-1830
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• 2012

Existing R-tree that is based on a variety of outdoor-based techniques to manage moving objects have been investigated. Due to the different characteristics of the indoor and outdoor, it is difficult to management of moving object using existed methods in indoor setting. We propose a new index structure called ACII(adaptive Cell-based index for Indoor moving objects) for Indoor moving objects. ACII is Cell-based access structure adopting an overlapping technique. The ACII refines cells adaptively to handle indoor regional data, which may change its locations over time. The ACII consumed at most 30% of the space required by R-tree based methods, and achieved higher query performance compared with r-tree based methods.

• 한국정보통신학회논문지
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• 제17권9호
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• pp.2191-2198
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• 2013

본 논문에서는 실내 위치 인식을 고려한 RFID 기반 셀 구성 방안을 제안하였다. RFID 셀 구성을 위한 4개의 목적함수 설계 및 시뮬레이션 기반 성능 평가뿐만 아니라 RFID 리더를 실내 공간에 실제 배치하여 제안한 기법의 성능평가를 수행하였다. 성능 평가는 RFID 셀 구성에 필요한 최소 RFID 리더 수, 위치 인식이 가능한 최대 셀 영역, 셀 영역 간의 최소 중첩, 그리고 셀 영역의 최대 위치 인식 정확도 측면에서 수행되었다.

• International journal of advanced smart convergence
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• 제8권3호
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• pp.54-60
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• 2019

In this paper, a localization system for indoor objects is proposed. The proposed system consists of Beacons, LED Cells, Main Cell Controller (MCC), and Display. A Beacon is attached at each indoor object, and each LED cell has Beacon Scanner and VLC Transmitter. The Visual Light Communications (VLC) and Power Line Communications (PLC) methods are used to communicate the signals for localization of indoor objects. And the proposed system is designed, and implemented as a prototype. To certify that our propose d system can exactly localize a given indoor object, we take test for the implemented system as a p rototype. Here the location of the given indoor object is known. Test is done in two ways. The first is to check the operation of the detail of the system, and the second is the position recognition of i ndoor object. The second is the test of the implemented system to correctly detect the location of the indoor object with Beacon, while the object with Beacon is moved from location C to A. The experimental result shows that the system is exactly detect the moving locations. The system has the advantages of using previously installed power lines, and it does not need to use LAN lines or optical cables. The proposed system is usefully applied to indoor object localization area.

• 한국컴퓨터정보학회논문지
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• 제21권6호
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• pp.55-62
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• 2016

In this paper, we present indoor positioning technologies using the wireless signal categorizing them into triangulation based, fingerprinting based, and cell ID based technologies. We describe several representative techniques for each of them emphasizing their strengths and weaknesses. We define important performance issues for indoor positioning technologies and analyze recent technologies according to the performance issues. We believe that this paper provide wise view and necessary information for recent indoor positioning technologies using wireless signals.

• 신재생에너지
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• 제5권4호
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• pp.34-37
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• 2009

Using six SMD(surface mount device) type AlGaAs/GaAs single junction solar cells connected in series, a power source was fabricated for a white GaN LED. The electrical properties of the power source was measured and analyzed under one sun (100mW/$cm^2$) and various indoor light (300 - 900 lux) conditions. Under 600 lux indoor light condition, output power was 17.06 ${\mu}W$ and it was 30.75 ${\mu}W$ under 900 lux indoor light condition. Using the fabricated solar cell power supply, we have turned on the white GaN LED. It was worked well under 15 ${\mu}W$(at 480 lux) power supplied from solar cell array. This kind of solar cell power supply can be used as a power source for ubiquitous sensor network (USN).

• 신재생에너지
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• 제5권3호
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• pp.22-25
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• 2009

For increasing the output voltage, six SMD(surface mount device) type AlGaAs/GaAs solar cells were connected in series. The electrical properties of the array were measured and compared with one sun (100 mW/$cm^2$) and indoor light (480 lux) conditions. Under one sun condition, output power was 21.57 mW and it was $14.67\;{\mu}W$ under indoor light condition. Under the indoor light condition, the intensity of the light is very low compared to one sun condition. Thus the Voc(open circuit voltage) and Isc (short circuit current) of the sample under indoor light condition decreased very much compared to that of under the one sun condition. This kind of solar cell power supply can be used as a power source for ubiquitous sensor network (USN).

• KIEAE Journal
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• 제1권2호
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• pp.21-28
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• 2001

Naturally-ocurring short-lived decay products of radon gas in indoor air are the dominant source of ionizing radiation exposure to the general public. It is written in BEIR VI Report(l999l the radon progeny were identified as the second cause of lung cancer next to cigarette or 10 % to 14 %(15,400 to 21,800 persons p.a.) of all lung cancer deaths in USA. Indoor radon concentrations in houses typically result from radon gaining access to houses mainly from the underlying soil. In the States, they have "Indoor Radon Abatement Act" which was converted from "Toxic Substance Control Act" in 1988 to establish the national long-term goal that indoor air should be as free of radon as the ambient air outside of buildings. To review and study techniques for controlling radon, two test cells were constructed for a series of tests and are under measuring indoor and soil gas (underneath of floor slab)radon concentrations according to EPA's measurement protocol. In this paper, important theoretical studies are previewed and the following paper will explain the test results and confirm the theories reviewed to find out suitable coefficients. On the basis of test analysis, it will be described and evaluated various techniques that can be used to mitigate elevated indoor concentration of radon including the control of radon and its decay products.

• 한국통신학회논문지
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• 제25권10B호
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• pp.1641-1647
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• 2000

This paper presents an analysis of coverage and capacity for the multi-layer CDMA cellular system. The multi-layer CDMA system that shares a common frequency band consists of macrocells for outdoor users and picocells for indoor users. Though macrocells and picocells interfere with each other the capacity of the whole system can be increased, We have analyzed the effect of muual interference upon cell coverage soft handover areas and capacities. The parameters involved in the engineering of the system are discussed. The study results sow that we can control the service coverage of indoor picocells with the system parameters set properly. It is also show that the capacity of the whole system that the capacity of the whole system can be enhanced smoothly by deploying the indoor picocells within existing macrocells.

• 한국컴퓨터정보학회논문지
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• 제17권6호
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• pp.173-182
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• 2012

최근 스마트 폰의 발전으로 위치 정보의 활용도가 높아지고 있다. 기존에 측위 시스템은 GPS를 이용한 위치 측위를 하였다. 하지만 실내는 GPS 신호를 사용할 수 없으며, GPS 사용할 경우 위치 부정확의 문제점이 발생된다. 실내에서의 측위 문제를 해결하기 위하여 실내를 기반으로 하는 위치 측위 기법이 연구되었다. 실내를 기반으로 하는 많은 측위 기법으로는 RFID, UWB, WLAN 등의 다양한 기법이 존재한다. 하지만 WLAN를 이용한 위치 측위기법이 실생활에 활용하기 가장 접합하다. WLAN을 이용한 실내 측위 기법은 크게 2가지로 나뉘는데 첫째는 삼각 측량 기법이고, 둘째는 핑거프린트 기법이다. 그중 핑거 프린트 기법이 정확도가 높기 때문에 많이 쓰인다. 하지만 핑거 프린트 기법을 사용하기 위해서 구축하는 시간이나 구축을 위한 자원 소모가 많은 단점이 있다. 본 논문에서는 이러한 문제점을 해결하기 위한 실내 환경에서 WLAN 기반의 가상의 핑거 프린트 구축 기법을 제안한다. 제안된 기법은 기존의 실내 환경을 셀 환경으로 구분하였으며, 각각의 셀 안의 핑거 프린트 위치 점을 가상의 그리드 맵으로 나타내었다. 그리고 가상의 위치점에 예측된 가상의 시그널 값을 넣어줌으로써 빠르게 핑거프린트 시스템을 구축한다. 또한 이렇게 구축된 시그널 값들은 실측위 값과는 다른 값을 가질수 있기 때문에 이러한 문제를 해결하기 위한 Splite-tree를 이용한 보정 기법을 제안한다. 보정 기법을 통하여 짧은 시간 동안 정확도가 향상됨을 보인다.

• 한국전자파학회논문지
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• 제21권3호
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• pp.285-291
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• 2010

본 논문에서는 조명용 LED와 솔라 셀을 사용하여 실내 무선광 통신이 가능함을 보인다. 조명용 LED를 광원으로 사용하면 조명과 신호의 송신을 겸할 수 있으며, 솔라 셀을 수광 소자로 이용하면 조명광을 수신하여 에너지를 축적하는 동시에 신호를 검출할 수 있기 때문에 별도의 통신 시설을 설치하지 않고 전송이 가능하여 매우 편리하다. 실험에서는 조명용 LED와 솔라 셀을 사용하여 9.6 kbps 속도로 무선광 데이터 전송을 실시하였다.