• Journal of the Korea Institute of Information and Communication Engineering
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• v.16 no.9
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• pp.2056-2063
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• 2012

In a port terminal, containers are stored and transshipped by yard tractors and crane vehicles. For operation efficiency of the terminal, location information of these vehicles is an essential factor. However, most of port terminals try to estimate location of these assets using indirect methods such as event tracking of shipping or unshipping containers. Because these kinds of events are rarely occurred, location of the event includes seriously locating error compared to a real location of vehicle. In this paper, we propose a real-time asset tracking system to obtain accurate and reliable location of terminal assets. The proposed system overcomes a location estimation error caused by container stacks which interrupt wireless communication. In order to mitigate uncertainty and increase accuracy of location estimation, we designed hardwares and multi-step locating system to resolve additional preblems. We implemented system components, and installed these at a port environment for evaluation. The result shows superiority of the system that the accuracy is approximately 5.87 meters (CEP).

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.12B
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• pp.1611-1622
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• 2011

The synchronization is one of the important issues for successful operation of femtocell. The synchronization of femtocell is distinctly different from that of larger wireless base stations in a number of important respects such as 1) The femtocell is located in indoor environment which may make it difficult to receive the adequate GNSS signals. 2) The backhaul of femtocell is connected to the public network which may have more PDV than private network. 3) The entire cost of femtocell needs to be very low. In our thesis, we investigate the candidate solutions including AGNSS (Assisted GNSS), NTP (Network Time Protocol), PTP (Precision Timing Protocol) and Cellular Network Listen for indoor timing solution. We propose the AGNSS-PTP Hybrid scheme which can improve time and frequency quality by selecting the better reference between AGNSS and PTP, and cover the standard status which are under discussion from IEEE, ITU-T, and IETF.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37 no.5B
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• pp.370-376
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• 2012

The CSS(Chirp Spread Spectrum) technology is used for developing various WPAN(Wireless Personal Area Network) application fields in general, and it can be adapted to implement localization systems especially using SDS-TWR(Symmetric Double Sided - Two Way Ranging). But the ranging errors are occurred in many practical applications due to some interferences by some experiments. Thus, the compensation algorithm for localization is required for developing localization applications. The suggested compensation algorithm that is named KF_EDR(Kalman Filter and Equivalent Distance Rate) for localization in order to reduce the ranging errors is suggested in this paper. The KF_EDR compensation algorithm for localization is mainly composed of the AEDR(Algorithm of Equivalent Distance Rate) and the Kalman Filter. It is confirmed that the improved error ratio of the KF_EDR are 10.5% and 4.2% compared with the AEDR algorithm in lobby and stadium. From the results, it is analyzed that the KF_EDR can be widely used for some localization system in ubiquitous society.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2009.10a
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• pp.1003-1006
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• 2009

Recently, Ubiquitous computing technology is increasing necessity for object recognition and a location tracking technology to meet various applications. The location tracking technology is the fundamental to the Context-Aware of users in Ubiquitous environment and its efficiency has to be improved using IEEE 802.15.4 ZigBee used in current infra such as ubiquitous sensor network. But because the IEEE 802.15.4 ZigBee protocol has limitation to apply location tracking technology such as ToA and TDoA, Zone-based Location Tracking technology using RSSI is needed. In this paper suggests RSSI-based 802.15.4 ZigBee local positioning protocol to support a positioning tracking service in Ubiqutous environment. And Zone-based location tracking system is designed for actual the indoor location tracking service.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.8
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• pp.657-661
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• 2019

The automobile industry is representative industry of complex characteristics, which employing 10 million people, the largest manufacturing industry over $1 trillion in sales and assembling with 20,000 parts to make complete automobile and automobile assembly processes have a lower automation rate than other processes, which is labor intensive processes of assembling to painted body with 3,000 components such as seats, built-in, instrument panel, glass, engine, transmission units. However, the current assembly process does not have real-time monitoring. If a tool position tracking system is adapted to assembly process for directing consistent work order and checking for missing work, the productivity and quality improvement of the assembly process can be achieved by preemptively preventing possible defects in the assembly process. So, this paper aims to develop a Tool Position tracking system using UWB(Ultra Wide Band) with trilateration and proves their effectiveness for real-time monitoring of automotive assembly process.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2014.05a
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• pp.475-478
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• 2014

This paper proposed the position tracking and recognition method of workers and cars in construction field. The reason why the position of workers and cars has to be tracked is to prevent the safety accident, emergency rescue, and theft of building materials by unauthorized people and car, etc. To realize the tracking, it needs to adopt the Information Telecommunication technology to the construction field as an integrated support system. In this paper, we proposed the continuous positioning tracking algorithm for workers and moving cars using the selected wireless communication network. And we proposed the virtual gateway method to detect the entrance status of moving workers and cars. All of these proposed methods are evaluated in real construction field using the prototype of support system made by ourselves.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2016.10a
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• pp.843-845
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• 2016

Concomitant with development of AR(Augmented Reality) and VR(Virtual Reality), interest in location based games and augmented reality have increased and various services have been developed. Due to this, AR, VR, MR(Merged Reality) techniques are considered one of fourth industrial revolution techniques. Oculus Rift which is representative of VR technology, and HTC VIVE need separate controllers, and don't offer service such as receiving external video information when users are using devices. In the case of project Alloy, which is a MR device of Intel, this has advantages such as controlling devices through hand signals and facial expressions, and receiving external video information. In this paper, we propose tourist guide system based on current position using MR. This system makes economical tour possible by arranging tourist attraction information which is from current position of tourists in correct places through external video information using MR, location determination using GPS, tourism information search using wireless internet.

• Journal of Advanced Navigation Technology
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• v.25 no.1
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• pp.60-67
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• 2021

Countries around the world, including the U.S. are actively researching to commercialize the logistics services using drones. In Korea, telecommunications companies as well as logistics companies are researching and developing the logistics services using drones. However, there's an environmental difference for last-mile delivery between the U.S. and Korea. In Korea, more than 77% of the population lives in apartments and the population density is the 4th highest in the world. Accordingly, in terms of the logistics services using drones, it is necessary to research it with the Korean suitable environment. In this paper, a precision positioning method of drone last-mile delivery in urban areas using short-range wireless communication and barometer is proposed. The experiment results show that the proposed method can detect a window within 2.5 meters. It is expected that the proposed method will help improve the logistics services using drones in urban areas.

• Journal of Korea Spatial Information System Society
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• v.7 no.2 s.14
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• pp.47-56
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• 2005

Recently, with the rapid development of mobile computing, wireless positioning technologies, and the generalization of wireless internet, LBS (Location Based Service) which utilizes location information of moving objects is serving in many fields. In order to serve LBS efficiently, the location data server that periodically stores location data of moving objects is required. Formerly, GIS servers have been used to store location data of moving objects. However, GIS servers are not suitable to store location data of moving objects because it was designed to store static data. Therefore, in this paper, we designed and implemented an extended SLDS(Short-term Location Data Subsystem) for real-time Location Based Services. The extended SLDS is extended from the SLDS which is a subsystem of the GALIS(Gracefully Aging Location Information System) architecture that was proposed as a cluster-based distributed computing system architecture for managing location data of moving objects. The extended SLDS guarantees real-time service capabilities using the TMO(Time-triggered Message-triggered Object) programming scheme and efficiently manages large volume of location data through distributing moving object data over multiple nodes. The extended SLDS also has a little search and update overhead because of managing location data in main memory. In addition, we proved that the extended SLDS stores location data and performs load distribution more efficiently than the original SLDS through the performance evaluation.

• 한국공간정보시스템학회:학술대회논문집
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• 2004.12a
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• pp.33-38
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• 2004

최근 들어 무선인터넷 및 모바일 컴퓨팅 기술의 급속한 발전과 함께 향후 그 수요가 증대될 것으로 예상되는 분야가 위치기반 서비스(LBS: Location Based Service) 기술이다. 위치기반 서비스는 이동 중인 사용자의 위치정보를 여러 가지 부가 서비스와 결합시켜 다양한 서비스를 제공하는 것으로 휴대 단말기와 무선 네트워크, 위치 측위 기술, 각종 응용 어플리케이션 등이 총체적으로 합쳐져 제공되는 서비스로 이동성, 개인성, 적시성 등을 사용자에게 제공해 주는 GIS의 차세대 핵심기술로 발전이 예상되는 분야이다[2][3]. 현재 미국, 유럽 등을 중심으로 3GPP/3GPP2, OMA, OGC, ISO, MAGIC 등의 국제 표준화 기구 및 단체에서 위치기반 서비스에 대한 표준화가 활발히 진행되고 있으며, 국내에서도 그 중요성을 인지하고 LBS 표준화에 정보, 업체, 학계 및 연구기관의 LBS 관련 전문가들로 구성된 LBS 표준화 포럼을 중심으로 국내 LBS 기술 표준을 위한 연구가 활발하게 진행되고 있다. 본 연구에서는 국내 LBS 표준들을 기반으로 위치기반 서비스에서 가장 기본적이고 핵심이 되는 서비스를 제공하는 표준 참조 시스템을 개발하고자 한다. 개발하고자 하는 표준 참조 시스템은 사용자의 위치를 추적하고 확인할 수 있는 위치추적 서비스와 주변 시설물 검색을 위한 디렉토리 서비스, 목적지까지의 경로를 안내하는 항법 서비스를 위한 기능 인터페이스 표준을 제공한다. 위치기반 서비스를 위한 표준 창조 시스템은 위치기반 응용 서비스의 기능 규격과 표준 인터페이스를 제공함으로써 위치기반 서비스 및 시스템 개발의 중복을 방지하고 상호 호환성을 확보 할 수 있다.문제에 적용이 가능한 창조 모델로 이용될 수 있을 것으로 생각된다.}94,\;29.4{\pm}30.3,\;45.1{\pm}44$로 Mel 10군과 Mel 30군이 유의적인 감소를 보였으나(p<0.05) 이들 두 군 간의 차이는 나타나지 않았다. 이상의 결과로, 랫트에서 복강수술 후 melatonin 10mg/kg투여가 복강 내 유착 방지에 효과적이라고 생각된다.-1}{\cdot}yr^{-1}$로서 두 생태계에 축적되었다.여한 3,5,7군에서 PUFA 함량이 증가한 반면, SFA 함량은 감소하여 P/S 비율, n-3P/n-6P 비율은 증가하는 경향이었으며 이는 간장의 인지질, 콜레스테롤 에스테르, 총 지질의 지방산조성에서도 같은 경향을 볼 수 있었다.X>$(C_{18:2})$와 n-3계 linolenic acid$(C_{18:3})$가 대부분을 차지하였다. 야생 돌복숭아 과육 중의 지방산 조성은 포화지방산이 16.74%, 단불포화지방산 17.51% 및 다불포화지방산이 65.73%의 함유 비율을 보였는데, 이 중 다불포화지방산인 n-6계 linoleic acid$(C_{18:2})$와 n-3계 linolenic acid$(C_{18:3})$가 지질 구성 총 지방산의 대부분을 차지하는 함유 비율을 나타내었다.했다. 하강하는 약 4일간의 기상변화가 자발성 기흉 발생에 영향을 미친다고 추론할 수 있었다. 향후 본 연구에서 추론된 기상변화와 기흉 발생과의 인과관계를 확인하고 좀 더 구체화하기 위한 연구가 필요할 것이다.게 이루어질 수 있을 것으로 기대된다.는 초과수익률이 상승하지만, 이후로는 감소하