• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.29 no.4
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• pp.270-276
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• 2018

Fifth-generation communications are approaching, and they will require broadband antennas that include the existing LTE frequency band (1.7 GHz to 2.7 GHz) and the newly allocated frequency band (3.4 GHz to 3.7 GHz). Many kinds of antennas satisfy the required broadband characteristics, including the dual-element folded dipole antenna proposed in this paper. A zigzag line was used to make the antenna more compact. This was accomplished by reducing the physical length while maintaining the electrical length. To validate the proposed antenna, a prototype was fabricated using PCB (${\epsilon}_r$:4.4, Height: 1.6 mm) and its performance was evaluated. Results obtained by simulation and experiment showed good agreement.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.25 no.12
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• pp.1927-1934
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• 2021

The AtoN are installed and operated on the sea in order to help the safe navigation of ships. With the development of maritime ICT, to monitor and control the condition of AtoN from land using multiplex communication network such as AtoN AIS, CDMA, and LTE. Currently, The information of AtoN is difficult to integrated manage because AtoN management systems has been independently developed and operatie according to the operating conditions of the Regional Office of Oceans and Fisheries. In addition, in preparation for the introduction for e-navigation and MASS, systematic and unified information of AtoN is required. In this paper, we study to design and develop standard software for AtoN management system based on the international standard for navigation information(S-201). Through this study, it will be possible to provide continuous AtoN information and effective AtoN management.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2022.06a
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• pp.304-305
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• 2022

Recently, as digital communication technology is widely applied to the maritime field, large amounts of maritime data are being accumulated. Accordingly, attempts to create new value by applying data science and Artificial Intelligence(AI) technologies are emerging. Typically, Ministry of Oceans and Fisheries has been providing korean e-Navigation service since 2021 based on LTE-Maritime communication network, as well as R&D for creating value-added service through analyzing huge-sized maritime traffic data is underway. By the way, to do any data-based research, legal system, as a research infra, that researchers can get the data whenever they need is essential. This paper looked at types of data in maritime fields, checked related legal system about scientific analysis and utilization. It is confirmed that there are some legal factors which restrict its scientific analysis and utilization, and suggested ways of improvement to boost R&D using maritime data as a conclusion.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.7 no.4
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• pp.188-194
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• 2014

In this paper, an antenna which has quad band in LTE (0.746 ~ 0.798 GHz), GSM(0.824 ~ 0.960 GHz), DCS(1.71 ~ 1.88 GHz), WCDMA(1.91 ~ 2.17 GHz) is proposed. An antenna size is $122mm{\times}50mm{\times}0.8mm$ on FR4(${\epsilon}_r=4.4$) ground substrate. In the proposed antenna, branch line is applied to the conventional PIFA architecture to achieve multi-bandwidth. Coupling power supply is applied for a wide bandwidth. Result of the measurement is as follows. When the low frequency, the antenna presents gain of 0.93 ~ 1.92dBi, and radiation efficiency of 49.60 ~ 76.35 %, and When the high frequency, gain is 2.19 ~ 4.66dBi, and radiation efficiency is 60.40 ~ 80.01 %, and with a VSWR < 2 (${\leq}-10dB$)measurement results for standard satisfies all band. Judging from the result, proposed multiband antenna is expected to be applied. B4G mobile terminals since the antenna shows an outstanding performance.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.6
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• pp.233-238
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• 2016

The purpose of this study is to investigate the reliability of static balance measurements using a smartphone. Thirty subjects were selected among university students who had no fractures, history of operation, or inflammatory arthritis, and they had not started regular exercise during the past three months. The smartphone used in this study was a Galaxy S5LTE (SM-G900F, Samsung, Korea, 2014), and the application was a Sensor Kinetics Pro (Ver. 2.1.2, INNOVENTIONS Inc., US, 2015). Static balance ability was measured three times at one-day intervals between tests and retests. The first and second measurements used the same process. Analysis was done using the Wilcoxon signed rank test and intraclass correlation coefficient (ICC (2,1)). The results were as follows. With eyes opened, there was no significant difference (p>0.05), a high volume of correlation (r>0.75, p<0.05), and very high reliability (ICC>0.80) between the first measurement and second measurement. With eyes closed, there was also no significant difference (p>0.05), a high volume of correlation (r>0.75, p<0.05), and very high reliability (ICC>0.80) between the measurements. The results show that the smartphone is likely accurate for measuring static balance. This study will look forward to being the only basis for measuring future application development and the ability to balance.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.5
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• pp.3071-3080
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• 2015

The increased demand on the transport of both passengers and goods through rail systems implies higher traffic intensity and congestion on the railways, resulting in greater likelihood of accidents and also degraded passenger services. To cope with the issues, development of an integrated communication network for rails has attracted great deal of attention lately. GSM-R is such an example developed in Europe, which seems to have restrictions in providing various communication services due to network speed limit. For the reason, an LTE-based approach is under study in Korea. After the network development, operation management of the network is necessary. Design of operation management systems has been studied little and thus is the objective of this paper. To do so, a conceptual design has been carried out based on model-based approach. Specifically, a context model has first been created using the use case diagram. Then, SysML models of operational scenarios were developed for the management system. The SysML models have alternatively been expressed as EFFBD models to simulate and verify them. Consequently, the result of the conceptual system design for the operation management of the integrated wireless network is expected to be used as a basis for the detailed design later.

• Journal of Digital Convergence
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• v.11 no.8
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• pp.359-365
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• 2013

Companies recently tend to move their business sites to a customer-centered location and the work place is changed from specific time and place to a working environment of anytime and anywhere the job can be done. Therefore, the design and implementation of business-work management system using mobile applications has been actively researched. In this study, the business-work management system, a mobile application using GPS, is immediately transmitted to ERP system and is stored into a company's formula DB, at such sites outside the company as business trip destinations, training institutions, and outside meetings, through smartphone-based GPS location information using WiFi, 3G, LTE, or 4G. In this way, it is aimed to design and develop the mobile application system to obtain rapid authorization in connection with electro nic document approval system. Also, this study is to measure the system's productivity and expected effects through the users' survey results by actual application of the designed and developed system to companies.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.25 no.4
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• pp.387-392
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• 2014

In this paper, the broadband antenna design, which can be applied to USB Dongle, supporting Wibro(2.3~2.4 GHz), Wi-Fi(2.4~2.5 GHz) and LTE7(2.5~2.7 GHz) is proposed technique. The proposed antenna was designed similar to PIFA type antennas. Reactive elements were used to control the input impedance and wideband characteristics were achieved by controlling coupling between the feed structure and the radiator. As a result, the antenna printed on FR-4 PCB(${\epsilon}_r$ =4.4, tan ${\delta}$=0.02) occupying an area of $15{\times}5mm^2$ was able to achieve bandwidth of 1 GHz from 2.1 to 3.1 GHz under VSWR=2. Measured return loss characteristics, bandwidth and radiation patterns were in good agreement with the simulated results.

• TTA Journal
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• s.175
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• pp.8-13
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• 2018

앞으로 대략 1년 뒤, 2019년 3월이면 우리나라에서 세계 최초로 5G 상용서비스가 시작된다. 1990년대 말에 cdmaOne, cdma2000 서비스, 2000년대 초 와이브로를 세계 최초로 상용화 했으며, HSDPA 서비스도 마찬가지였다. LTE는 날짜상으로는 스웨덴 대비 조금 늦게 시작하기는 했으나, 전국규모의 서비스 개시 시점을 고려하면 이것도 한국이 사실상 세계 최초라고 말할 수 있다. 그러나 5G 상용서비스 세계 최초라는 의의는 기존의 세계 최초 기록과는 차원을 달리한다고 말할 수 있다. 왜냐하면 ITU-R에서 5G의 비전과 로드맵 작업을 5G는 시기상조라는 반대를 무릅쓰고 한국이 주도했고, 많은 전문가들이 회의적이었던 밀리미터파 주파수 대역의 이동통신 활용 가능성을 한국에서 처음으로 주장했으며, 여러 가지 밀리미터파 대역 중 28GHz 주파수 대역을 선택하여 지지를 수렴해 온 것도 한국이다. 또한 최근 3GPP, ITU-R 표준에서도 당당히 주도세력 중의 하나로 자리매김하고 있으며, 2018년 겨울 올림픽이라는 절묘한 시범 서비스 기회를 행운으로 갖고 있기도 하다. 그러나 상용화를 1년 남짓 남겨두고 있는 지금의 상황은 과거 몇 년과는 사뭇 다른 양상을 보여주고 있다. 과거 5G의 미래가 불확실할 때에는 눈치를 보면서 소극적 자세를 보이던 세력들이 지금처럼 기술, 표준, 시장에 대한 위험도가 많이 사라진 틈을 타, 저마다 실리를 챙기기 위해서 오히려 적극적으로 돌변하고 있다. 기존 이동통신 시장규모는 대략 서비스-디바이스-인프라 장비의 비중이 30:10:1 정도 된다. 표준을 적기에 지원하는 제품과 서비스의 개발 및 이를 지원하는 생태계가 구축되지 않으면 모처럼 어렵게 만들어온 5G 시대의 열매를 정작 우리는 맛보지 못하는 어처구니 없는 일이 생길 수도 있다. 아무쪼록 본 특집을 통해 많은 분들이 5G의 현황을 제대로 이해하고, 이것을 도약대로 삼아서 알찬 5G 시대의 수확을 준비하는 계기가 되었으면 하는 바람이다.

• Information and Communications Magazine
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• v.31 no.10
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• pp.19-24
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• 2014

광대역 기술을 적용한 재난통신망 구축에 대한 관심이 증가함에 따라 이에 필요한 주파수 자원 확보에 관해서도 활발한 논의가 진행되고 있다. 미국, 유럽 등 주요국을 중심으로 LTE를 이용한 광대역 시스템용 주파수가 분배가 논의되고 있고, 국제 조화 주파수 대역을 결정하는 ITU-R에서도 광대역 PPDR 주파수 대역 분배를 논의 중에 있다. 재난통신용 주파수 대역 선정을 위해서는 재난통신용도의 활용 적합성이 우선적으로 고려되어야 하고, 경제적 망 구축 가능성, 국제적 조화 주파수 여부, 적기 활용 가능성 등이 검토되어야 한다. 이러한 사항을 고려할 때 국내에서 활용 가능한 대역으로는 700MHz 대역이 가장 적합한 후보대역으로 판단된다. 주파수 활용이 평시, 재난시에 따라 크게 변하는 재난통신용 트래픽 특성을 고려할 때 평시의 효율적 주파수 활용방안 강구가 필수적이다. 이에 따라 철도, 연안선박 광대역 서비스 등과 연계하여 재난통신망 주파수의 이용 효율성을 증대할 뿐만 아니라 공공 사물인터넷 등 다양한 공공용 서비스 개발이 필요하다.