• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.18 no.2
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• pp.157-162
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• 2018

Tracking the location of patients in medical facilities is important to guarantee the patients' safety and to improve the service quality. Previous studies related to location tracking systems based on Bluetooth communication need numerous prerequisite information and multiple devices to improve the accuracy. In this paper, we propose a beacon-based space partition scheme that assigns different arrangement patterns of beacons to different spaces and composes groups with the similar value of RSSI to minimize prerequisite information and the number of beacons. The proposed scheme considers a pattern arrangement scheme to minimize intereference between neighbor patterns. We also verified the applicability of our scheme to monitor the patient location by using experimental results.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.40 no.1
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• pp.124-131
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• 2015

In this paper, we proposed indoor positioning system using RSS(Received Signal Strength) positioning method and TSS(Transmission Signal Strength). The main point in the paper is to improve reliability of accuracy positioning with the area recognition algorithm and probabilistic algorithm, which can be effectively used indoor. In the test in 1-dimensional or 2-dimensional spaces, also we checked effective positioning system considered environment of propagation that is changed by reflection, refraction and multipath in according to space form. It is necessary to find place where urgent situation happen and quickly to respond the situation for patients or the weak. Therefore, we expect the positioning system proposed can apply to the field of traffic IT.

• Proceedings of the Korea Information Processing Society Conference
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• 2022.11a
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• pp.908-909
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• 2022

인체의 미세먼지 노출에 의한 연구가 활발히 진행되면서 미세먼지와 건강 영향에 대한 인과 관계가 입증되고 있다. 미세먼지는 기침, 재채기, 심혈관 질환, 폐암 등 가벼운 증상부터 심각한 질병까지 인체의 건강에 다양하게 영향을 미칠 수 있다. 미세먼지는 2000 년 초부터 꾸준히 높은 농도를 보여왔지만, 사람들이 실제로 미세먼지를 위험 물질로 인식하기 시작한 것은 10 년이 채 되지 않았다. 이에 본 논문은 실외 미세먼지에 대한 정보 제공뿐만 아니라 사용자가 실제로 위치한 실내 미세먼지 농도까지 함께 제공하여 미세먼지에 관한 관심을 증가시키고자 한다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.22 no.2
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• pp.302-313
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• 2018

As the demand for indoor location recognition system has been rapidly increased in accordance with the increasing use of smart devices and the increasing use of augmented reality, indoor positioning systems(IPS) using BLE (Bluetooth Lower Energy) beacons and UWB (Ultra Wide Band) have been developed. In this paper, a positioning plate is generated by using trilateration technique based on BLE Beacon and using RSSI (Received Signal Strength Indicator). The resultant value is used to calculate the PDR-based coordinates using the positioning element of the Inertial Measurement Unit sensor, We propose a precise indoor positioning algorithm that combines RSSI and PDR technique. Based on the plate algorithm proposed in this paper, the experiment have done at large scale indoor sports arena and airport, and the results were successfully verified by 65% accuracy improvement with average 2.2m error.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.3
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• pp.327-332
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• 2017

As Internet of Things (IoT) technology advances, there is a growing demand for location-based services (LBSs) to identify users' mobility and identity. The initial LBS system was mainly used to measure position information by measuring the phase of a signal transmitted from a global positioning system (GPS) satellite or by measuring distance to a satellite by tracking the code of a carrier signal. However, the use of GPS satellites is ineffective, because it is difficult to receive satellite signals indoors. Therefore, research on wireless communications systems like ultra-wide band (UWB), radio frequency identification (RFID), and ZigBee are being actively pursued for location recognition technology that can be utilized in an indoor environment. In this paper, we propose an LBS system that includes the 2.45GHz band for chirp spread spectrum (CSS), and the 3.1-10.6GHz band and the 250-750MHz bands for UWB using the IEEE 802.15.4a standard for low power-based location recognition. As a result, we confirmed that the 2.45GHz Industrial, Scientific and Medical (ISM) band RF transceiver and the ranging function can be realized in the hardware and has 0dBm output power.

• Journal of Internet of Things and Convergence
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• v.10 no.2
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• pp.69-75
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• 2024

This paper proposes an IoT-based indoor autonomous driving system that applies SLAM (Simultaneous Localization And Mapping) and Navigation techniques in a ROS (Robot Operating System) environment based on TurtleBot3. The proposed autonomous driving system can be applied to indoor autonomous wheelchairs and robots. In this study, the operation was verified by applying it to an indoor self-driving wheelchair. The proposed autonomous driving system provides two functions. First, indoor environment information is collected and stored, which allows the wheelchair to recognize obstacles. By performing navigation using the map created through this, the rider can move to the desired location through autonomous driving of the wheelchair. Second, it provides the ability to track and move a specific logo through image recognition using OpenCV. Through this, information services can be received from guides wearing uniforms with the organization's unique logo. The proposed system is expected to provide convenience to passengers by improving mobility, safety, and usability over existing wheelchairs.

• Journal of the Korean Institute of Intelligent Systems
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• v.26 no.4
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• pp.253-258
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• 2016

This paper proposes a method that utilizes optimization approach for localization of an indoor mobile robot. Bayesian filters which have been widely used for localization of a mobile robot use many control parameters to take the uncertainties in measurement and environment into account. The estimation performance depends on the selection of these parameter values. Also, the performance of the Bayesian filters deteriorate as the non-linearity of the motion and measurement increases. On the other hand, the optimization approach uses fewer control parameters and is less influenced by the non-linearity than the Bayesian methods. This paper compares the localization performance of the proposed method with the performance of the extended Kalman filter to verify the feasibility of the proposed method. Measurements of ranges from beacons of ultrasonic satellite to the robot are used for localization. Mahalanobis distance is used for detection and rejection of outlier in the measurements. The optimization method sets performance index as a function of the measured range values, and finds the optimized estimation of the location through iteration. The method can improve the localization performance and reduce the computation time in corporation with Bayesian filter which provides proper initial location for the iteration.

• Journal of the Korea Society of Computer and Information
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• v.24 no.11
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• pp.135-142
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• 2019

In this paper, we propose a system that can identify the position of naval ship personnel at a glance by utilizing the Bluetooth-based beacons. The system proposed in this paper, installs a beacon receiver which are short-range wireless communication devices for each cabin, and in the installed beacon receiver receives information from beacons held by personnel. The received information is transmitted to the processing server, and the processing server transmits the integrated information of the cabin to the display module. Display module displays personnel information located in each cabin. As a result of simulations using the designed system, it was confirmed that the integrated information is transferred to the display module and displayed. Unlike existing situations where personnel positions are reported orally within the ship, the system can quickly and in real time determine the position of personnel, allowing for the management of personnel in non-combat situations and the rapid battle disposition in combat situations. This is expected to contribute greatly to the improvement of fighting power.

• KIPS Transactions on Computer and Communication Systems
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• v.12 no.3
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• pp.93-102
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• 2023

Data processing through the cloud causes many problems, such as latency and increased communication costs in the communication process. Therefore, many researchers study edge computing in the IoT, and autonomous driving is a representative application. In indoor self-driving, unlike outdoor, GPS and traffic information cannot be used, so the surrounding environment must be recognized using sensors. An efficient autonomous driving system is required because it is a mobile environment with resource constraints. This paper proposes a machine-learning method using neural networks for autonomous driving in an indoor environment. The neural network model predicts the most appropriate driving command for the current location based on the distance data measured by the LiDAR sensor. We designed six learning models to evaluate according to the number of input data of the proposed neural networks. In addition, we made an autonomous vehicle based on Raspberry Pi for driving and learning and an indoor driving track produced for collecting data and evaluation. Finally, we compared six neural network models in terms of accuracy, response time, and battery consumption, and the effect of the number of input data on performance was confirmed.

• Proceedings of the IEEK Conference
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• 2005.11a
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• pp.265-268
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• 2005

본 논문에서 제안하는 방안은 Cricket 방식을 사용하는 위치 인식 시스템에서 전력 소모를 억제하는 방안이다. 복수의 전송 모듈인 Beacon 과 유저당 한 개씩 갖게 되는 수신모듈 Listener 로 구성되는 기본적인 Cricket 구조에서 전송 모듈인 Beacon 은 일반적으로 랜덤 방식으로 송신을 행하게 된다. 이럴 경우 사용자가 없는 구역의 Beacon 이 초음파를 계속 발생함으로써 불필요한 전력 낭비가 생긴다. 이를 막기 위해 사용자가 있는 구역의 Beacon 들에게 우선순위를 부여하여 이 Beacon 들이 우선적으로 전송을 행하게 하는 방안을 고안한다. 이 방안은 시스템의 규모가 클수록 그 효율을 발휘한다. 유저가 있는 영역의 시스템만 가동되므로 불필요한 Beacon 전력 낭비를 줄일 수 있기 때문이다. 본 논문에서는 기본적인 Cricket 구조의 설명에 이어, 제안하는 방안에 대해 논하고 마지막으로 시뮬레이션을 통한 성능 분석을 행하였다.