• 대한임베디드공학회논문지
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• 제9권6호
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• pp.323-334
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• 2014

In this paper, we proposed indoor positioning system with improved accuracy. The proposed indoor location measurement system is based pedestrian location measurement method that use the embedded sensor of smartphone. So, we do not need wireless external resources, such as GPS or WiFi signals. The conventional methods measure indoor location by generating a movement route of pedestrian by step and direction recognition. In this paper, to correct the direction sensor error, we use the common feature of the normal indoor floor map that the indoor path is lattice-structured. And we quantize moving directions depending on the direction of indoor path. In addition, we propose moving direction measuring method using geomagnetic sensor and gyro sensor to improve the accuracy. Also, the proposed step detection method uses angle and accelerometer sensors. The proposed step detection method is not affected by the posture of the smartphone. Direction errors caused by direction sensor error is corrected due to proposed moving direction measuring method. The proposed location error correction method corrects location error caused by step detection error without the need for external wireless signal resources.

• 한국측량학회지
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• 제34권3호
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• pp.329-338
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• 2016

최근 실내공간정보에 대한 수요가 증가함에 따라 다양한 활용 서비스가 개발되고 있다. 그동안 2차원 또는 3차원 실내공간정보 서비스에서, 최근에는 전방위 영상 기반의 실내공간정보 서비스가 증가하고 있다. 단순히 실내공간의 가시화만을 제공하는 기존 전방위 영상 기반 서비스가 속성 검색, 질의 가능 서비스 등을 제공하기 위해서는 공간간의 위치 관계가 정의된 토폴로지 데이터가 반드시 필요하다. 이에 따라 본 연구에서는 전방위 영상 기반의 다양한 실내공간정보 서비스를 위해 필요한 실내 토폴로지 데이터를 국제 표준인 IndoorGML 형식에 맞춰 생성하는 방법을 제안하도록 한다. 본 연구에서는 영상으로부터 IndoorGML 데이터 생성을 위해 1)IndoorGML 기본 개념의 영상 적용을 위한 고려사항 분석, 2)IndoorGML 데이터 생성을 위해 필수 정의 요소인 ‘공간’을 대표하는 객체 식별 방법 제시, 3)공간 사이의 연결성을 정의로 구분하여 IndoorGML 데이터 생성 방법을 제안한다. 제안한 방법은 서울시립대학교 21세기관 6층을 대상으로 적용되어 IndoorGML 데이터를 생성하도록 한다. 본 연구는 향후 IndoorGML을 기반으로 개발되는 다양한 실내공간정보 서비스에 토폴로지 데이터를 생성하는 한 가지 유형의 방법을 제시한다는 점에서 의의가 있다.

• 국제학술발표논문집
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• The 6th International Conference on Construction Engineering and Project Management
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• pp.674-675
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• 2015

A 3D indoor model becomes an indiscernible component of BIM (Building Information Modeling) and GIS (Geographic Information System). However, a huge amount of time and human resources are inevitable for collecting spatial measurements and creating such a 3D indoor model. Also, a varied forms of 3D indoor models exist depending on their purpose of use. Thus, in this study, three different 3D indoor models are defined as 1) omnidirectional images, 2) a 3D realistic model, and 3) 3D indoor as-built model. A series of reconstruction methods is then introduced to construct each type of 3D indoor models: they are an omnidirectional image acquisition method, a hybrid surveying method, and a terrestrial LiDAR-based method. The reconstruction methods are applied to a large and complex atrium, and their 3D modeling results are compared and analyzed.

• 로봇학회논문지
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• 제6권1호
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• pp.58-68
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• 2011

This paper proposes a technique of indoor localization for mobile robot by so called indoor GPS and EKF. Basically the concept of indoor GPS is similar outdoor GPS, and the indoor GPS gets distances between Anchors and Tag by a ranging method of CSS and then estimates the coordinate by distances and known Anchor positions. After we performed performance test of indoor GPS system in ideal and multipath environment, we configured that the indoor GPS has internal error factors and external error factors. This paper handled a multipath problem belonging to external error factors. At first various direct physical method are introduced to fix the multipath problems, and as expected we got errors corrected considerably. And then the method of selective anchors for indoor GPS is applied. With these two level improvement of indoor GPS performance, EKF(Extended Kalman Filter) is applied to mobile robot in indoor environment. The usefulness of the proposed methods are shown by a series of experiments in a environment giving contaminated data by multipath.

• 설비공학논문집
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• 제16권2호
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• pp.111-120
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• 2004

The optimal design method of indoor thermal environment using CFD coupled simulation and genetic algorithms (GA) is developed in this study. CFD could analyze the thermal environment considering the distribution of temperature, velocity, etc. in a room. Therefore, It would be appropriate to use CFD for the optimal design method considering their distribution. In this paper, the optimal design means the most appropriate boundary conditions of the room among the conditions where the design target of indoor therm environment is achieved. Two step optimal indoor thermal environment design method is proposed. It includes the GA for searching the optimal indoor thermal environment design. To examine the performance of this method, the optimal design of hybrid ventilation system, which uses the natural cross ventilation and the radiation-cooling panel is conducted. The optimal design which satisfies the design target (thermal comfort, minimum cooling load, minimum vertical temperature difference) is found using two step optimal design method.

• 한국측량학회지
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• 제38권6호
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• pp.623-633
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• 2020

사람들이 실내공간에서 소비하는 시간이 증가함에 따라, 실내공간을 대상으로 하는 서비스들에 대한 수요가 지속적으로 증가하고 있다. 실내공간정보 서비스를 제공하기 위해서는 실내공간정보를 구축하는 것이 우선적으로 이루어져야 하며 본 연구에서는 기 구축되어 있는 BIM (Building Information Management) 데이터로부터 실내공간정보 국제표준 데이터인 IndoorGML을 생성하는 방법을 제안하였는데 대표적인 BIM 데이터 자료인 IFC (Industry Foundation Class) 데이터를 IndoorGML로 변환하기 위하여 IFC 객체들의 특성을 조사하고, IndoorGML로 변환이 필요한 객체들을 선별하였으며 실내공간의 표현과 내부통행에 제약을 주는 객체로 구분하였다. 또한 개발된 변환도구를 이용하여 빔서버(BIMserver) 깃헙(github)에서 제공하는 데이터 셋 일부와 서울시립대학교 21세기관 IFC모델을 IndoorGML의 PrimalSpaceFeatures 데이터로 구축하는 실험을 수행하였다. 각각의 IFC 데이터를 IndoorGML로 변환한 결과 기하정보를 손실 없이 IndoorGML문서가 생성되었으며, IndoorGML이 가지고 있는 특징인 NavigableBoundary가 정확하게 생성되는 결과를 보였다. 추후, 다양한 형태의 IfcStair 객체를 변환하는 방법에 대한 추가적인 연구가 필요하며, 프라이멀 스페이스(PrimalSpace) 데이터를 이용하여 듀얼 스페이스(DualSpace) 데이터인 MultiLayeredGraph를 자동 생성하는 방법에 대한 개발이 필요하다.

• 국제학술발표논문집
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• The 9th International Conference on Construction Engineering and Project Management
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• pp.1170-1178
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• 2022

Indoor POI data, an essential component of indoor spatial data, has attribute information of a specific place in the room and is the most critical information necessary for the user. Currently, indoor POI data is manually updated by direct investigation, which is expensive and time-consuming. Recently, research on updating POI using the attribute information of indoor photographs has been advanced to overcome these problems. However, the range of use, such as using only photographs with text information, is limited. Therefore, in this study, and to improvement this, I proposed a new method to update indoor POI data using a smartphone camera. In the proposed method, the POI name is obtained by classifying the indoor scene's photograph into artificial intelligence technology CNN and matching the location criteria to indoor spatial data through AR technology. As a result of creating and experimenting with a prototype application to evaluate the proposed method, it was possible to update POI data that reflects the real world with high accuracy. Therefore, the results of this study can be used as a complement or substitute for the existing methodologies that have been advanced mainly by direct research.

• Journal of Positioning, Navigation, and Timing
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• 제10권2호
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• pp.121-130
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• 2021

In this paper, we propose a method to improve the positioning accuracy of TOA based indoor positioning system in NLOS environments. TOA based indoor positioning systems have been studied mostly considering LOS environments. However, it is almost impossible to maintain the LOS environments due to obstacles such as people, furniture, walls, and so on. The proposed method in this study compensates the range error caused by the NLOS environments. We confirmed that positioning accuracy of a proposed method is improved than conventional algorithms through simulation and field test.

• Journal of Information Processing Systems
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• 제13권6호
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• pp.1640-1651
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• 2017

To make an unmanned aerial vehicle (UAVs) fly in indoor environments, the indoor locations of the UAV are required. One of the approaches to calculate the locations of an UAV in indoor environments is enhanced trilateration using one Bluetooth-based beacon and three or more access points (APs). However, the locations of the UAV calculated by the common chord-based trilateration has errors due to the distance errors of the beacon measured at the multiple APs. This paper proposes a method that corrects the errors that occur in the process of applying the common chord-based trilateration to calculate the locations of an UAV. In the experiments, the results of measuring the locations using the proposed method in an indoor environment was compared and verified against the result of measuring the locations using the common chord-based trilateration. The proposed method improved the accuracy of location measurement by 81.2% compared to the common chord-based trilateration.

• 전기전자학회논문지
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• 제26권2호
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• pp.186-195
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• 2022

In this paper, we propose a new algorithm to improve the accuracy of indoor positioning techniques using Wi-Fi access points as beacon nodes. The proposed algorithm is based on the Weighted Centroid algorithm, a popular method widely used for indoor positioning, however, it improves some disadvantages of the Weighted Centroid method and also for other kinds of indoor positioning methods, by using the received signal strength correction method and genetic algorithm to prevent the signal strength fluctuation phenomenon, which is caused by the complex propagation environment. To validate the performance of the proposed algorithm, we conducted experiments in a complex indoor environment, and collect a list of Wi-Fi signal strength data from several access points around the standing user location. By utilizing this kind of algorithm, we can obtain a high accuracy positioning system, which can be used in any building environment with an available Wi-Fi access point setup as a beacon node.