• Journal of Internet of Things and Convergence
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• v.9 no.2
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• pp.71-76
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• 2023

In this paper, we propose a smoothed received signal strength indicator (RSSI)-based distance estimation using deep neural network (DNN) for accurate distance estimation in an environment where a single receiver is used. The proposed scheme performs a data preprocessing consisting of data splitting, missing value imputation, and smoothing steps to improve distance estimation accuracy, thereby deriving the smoothed RSSI values. The derived smoothed RSSI values are used as input data of the Multi-Input Single-Output (MISO) DNN model, and are finally returned as an estimated distance in the output layer through input layer and hidden layer. To verify the superiority of the proposed scheme, we compared the performance of the proposed scheme with that of the linear regression-based distance estimation scheme. As a result, the proposed scheme showed 29.09% higher distance estimation accuracy than the linear regression-based distance estimation scheme.

• International Journal of Advanced Culture Technology
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• v.6 no.3
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• pp.216-225
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• 2018

Strangely enough, there has not been much effort in applying the latest technologies to help referees make accurate calls in a soccer game compared to other sports. Modern soccer tries to apply VAR (Video Assistant Referee) technology to correct inaccurate calls such as an offside, but this is being put off due to the fact that real time decision-making cannot be carried out by using this technology. This has led this study to decide developing a device that will accurately identify offsides on a real time basis using various latest sensors and related technologies. This device will aid referees in calling offsides in a soccer match.

• Proceedings of the Korean Society of Computer Information Conference
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• 2017.07a
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• pp.326-327
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• 2017

저전력 블루투스가 공개 된 이후 저전력 블루투스 비콘을 이용한 서비스들이 출시되고 있다. 비콘 기반 서비스는 사용자의 스마트폰이 블루투스 기능을 활성화해두었을 때, 일정한 주기의 블루투스 스캐닝을 통해 이용할 수 있다. 블루투스 비콘이 밀집된 실내 공간의 경우, 동일한 비콘이 중복 탐지되거나 사용자가 사용하지 않을 먼 거리의 비콘까지 탐지하게 되므로 스마트폰에서 불필요한 에너지 소모가 발생한다. 이러한 문제를 해결하고자 본 연구에서는 실내 구획화를 통해 동일 영역 내에서 비콘이 중복으로 탐지되는 것을 방지하는 방법과, 사용자 이동성에 따른 동적 스캐닝 주기 최적화를 통해 밀집된 실내 공간에서도 누락되는 비콘 신호를 최소로 하는 기법을 제안한다. 이러한 사용자 이동성에 기반한 스캐닝 주기 최적화 방법은 스마트폰의 전력소모량을 감소시킨다.

• Proceedings of the Korea Information Processing Society Conference
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• 2019.05a
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• pp.709-710
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• 2019

제안 시스템은 모바일 사용자를 공공 인터넷 환경에서 사용 유형별로 분류 및 관리 가능한 서비스를 제공한다. 비콘을 이용하여 시스템 사용자의 위치와 서비스공간의 근접성을 확인한다. 또한 사용자의 서비스 사용 형태 및 성향에 따라 서비스 제공 장소에서 네트워크에 연결된 사물 인터넷 기기 및 기타 기기에 대한 접근 권한을 미리 정의하고 이를 제공할 수 있다. 본 연구는 이러한 시스템을 제안하고 구현된 결과를 바탕으로 시스템의 기능을 분석한다.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.16 no.5
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• pp.265-271
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• 2023

Recently, location information services are gradually expanding due to the development of information and communication technology. RSSI is widely used to extract indoor and outdoor locations. The indoor and outdoor location estimation methods using RSSI are less accurate due to the influence of radio wave paths, interference, and surrounding wireless devices. In order to improve this problem, a distance estimation method that takes into account the wireless propagation environment is necessary. Therefore, in this study, we propose a distance estimation algorithm that takes into account the radio wave environment. The proposed method estimates the distance by learning RSSI input and output considering the RBF neural network and the propagation environment. To evaluate the performance of the proposed method, the performance of estimating the location of the receiver within a range of up to 55[m] using a BLE beacon transmitter and receiver was compared with the average filter and Kalman filter. As a result, the distance estimation accuracy of the proposed method was 6.7 times higher than that of the average filter and Kalman filter. As shown in the results of this performance evaluation, if the method of this study is applied to location services, more accurate location estimation will be possible.

• The Journal of the Korea Contents Association
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• v.16 no.8
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• pp.202-208
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• 2016

The scope of activities of the visually impaired is increasing. But they are not easy to visit the destination safely because the building was complicated and larger than ever. There is a guide system for visually impaired such as GPS and Audio alerts, Braille guide block, Acoustic signaller, etc. But they are not suitable for indoor because most of them are the outdoor guide system. Therefore, in this paper, I propose a system that provides guidance information to the visually impaired using Voice Technology, TTS (Text to Speech) and Haptic Technology, Beacon based on the wireless sensor networks. It informed the visually impaired of guidance information about destination such as distance, height, and obstacle to the destination using the generalized smart phone. The user could be received guide info about searches for the optimal route to the destination using the TTS technology and Haptic technology in test result of the proposed system.

• Journal of Information Processing Systems
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• v.15 no.1
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• pp.217-232
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• 2019

Currently, the crew working on a ship is required to carry a seafarer's book in most countries around the world, including the Republic of Korea (ROK). Yet, many fishermen working in the international waters of the ROK do not abide by this rule as the procedure of obtaining it is rather inconvenient or they do not understand the necessity or the benefits of having it. Also, as the regulation of carrying the certificate has been strengthened, it is important for them to avoid making a criminal record unintentionally. This study discusses the digitalization of the seafarer's book based on several security measures in addition to BLE Beacon-based positioning technology, which can be useful for the e-Navigation. Normally, seamen's certificates are recorded by the captain, medical institution, or issuing authority and then kept in an onboard safe or a certificate cabinet. The material of the certificates is a cloth that can withstand salinity as the certificate could be contaminated by mold. In the past, the captains and their crews were uncooperative when the ROK's maritime police tried to inspect several ships simultaneously because of the time and cost involved. Thus, a system with which the maritime police will be able to conveniently manage the crews is proposed.

• International Journal of Computer Science & Network Security
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• v.24 no.3
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• pp.83-92
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• 2024

It is a common observation that whenever any patient arrives at the front desk of a hospital, outpatient clinic, or other health-associated centers, they have to first queue up in a line and wait to fill in their registration form to get admitted. The long waiting time without any status updates is the most common complaint, worrying health officials. In this paper, UrNext, a location-aware mobile-based solution using Bluetooth low-energy (BLE) technology, is presented to solve the problem. Recently, a technology-oriented method has been gaining popularity in solving the healthcare sector's problems, namely the Internet of Things (IoT). The implementation of this solution could be explained through a simple example that when a patient arrives at a clinic for her consultation. There, instead of having to wait in long lines, she will be greeted automatically, receive a push notification telling her that she has been admitted along with an estimated waiting time for her consultation session. This will not only provide the patients with a sense of freedom but would also reduce uncertainty levels that are generally observed, thus saving both time and money. This work aimed to improve clinics' quality of services and organize queues and minimize waiting times in clinics, leading to patient comfortability and reducing the burden on nurses and receptionists. The results demonstrated that the presented system was successful in its performance and helped achieve high usability.

• Proceedings of the Korea Information Processing Society Conference
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• 2017.11a
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• pp.1106-1108
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• 2017

현재 규모가 작은 이름바 '동네 병원'에서는 환자관리의 어려움과 동네 병원의 특성상 병원 자체적인 예약 서비스를 실시하지 않는 병원이 많다. 또한 환자는 기다리는 환자들이 많은 시간에 방문하는 경우, 병원 안에서 자신의 순번을 마냥 기다리는 경우가 빈번하게 발생한다. 이와 같은 불편들 때문에 간호사는 고객에게 간호업무 이외에도 정신적인 서비스를 제공해야 하며, 환자들은 자신의 순번이 오기만을 하염없이 기다리는 등의 불필요한 시간 소모가 크고 자신의 앞에 대기하고있는 환자가 많으면 병원이 어수선하고 앉을 자리조차 없이 서서 기다리는 경우도 허다하다. 이런 불편함들을 조금이나마 해결해주고자 본 논문에서는 저전력 블루투스 (BLE) 기술 기반의 비콘(Beacon)을 활용하여 스마트폰을 이용해 병원 내부적인 예약 서비스가 없어도 자체적인 예약 서비스와 이용자가 스마트폰을 가지고 병원에 들어가기만 해도 자동으로 병원 진료접수를 진행하고 이를 효과적으로 관리할 수 있는 사물인터넷 기반 병원 대기시간 최적화 서비스와 그 핵심 알고리즘을 제안한다. 이를 이용하면 간호사는 이전보다 간호업무에 더 집중할 수 있게 되고, 환자는 북적거리는 병원 대기실에 앉아서 기다리지 않고 실외로 나가 자신의 업무를 보고 진료시간에 맞춰서 돌아와 진료를 받는 '사람이 많아도 한적해 보이는 스마트 병원'을 만들 수 있을 것이라 본다.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.13 no.6
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• pp.496-502
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• 2020

The electronic attendance management system is being introduced and operated on a pilot basis by some universities and educational institutions. However, most of the related systems have installed and operated the existing barcode and magnetic card systems. Classroom attendance is managed by introducing RF cards, but it causes problems such as recognition distance (less than 5cm) and the need for a check process in which students have to read the card each time with a reader for attendance. Also, it is not possible to respond in real time to the situation of midterm (early leave, absence from the second lecture time, etc.) because it is used in the lecture time of one subject with the record checked once. In order to solve these problems, the various mobile attendance systems proposed to solve these problems are also unable to fundamentally solve problems such as interim attendance and proxy attendance because they check attendance using only the application of a smartphone. In this paper, we use geofencing technology, which is a positioning-based technology that detects the entry and exit of people, objects, etc. in areas separated by virtual boundaries. The proposed system solves the problem of intermediate attendance and alternate attendance by setting the student to automatically record the access record when entering and leaving the classroom set as a geofence with a smartphone. In addition, it also provides a function to prevent unintentional mistakes that occur through the smartphone by limiting some of the functions of the smartphone such as silence, vibration, and Internet use when entering the classroom.