• 한국벤처창업학회:학술대회논문집
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• 2018.11a
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• pp.277-281
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• 2018

Information system has been at center of economic development in several developed countries, and as Africa envision to improve its global economic competitiveness it is important to assess penetration rate the digital divide and catch-up effect over the years. This paper examined whether there exists digital divide and if so, is it narrowing over time and whether the ICT is converging with time in the African countries. Three technologies namely mobile-cellular, internet and fixed broadband were used to measure the digital divide and the catch-up effect. Gamma and sigma convergence methodology together with averaged penetration ratios were used to assess the cross-country performance of each technology. This study confirms both the narrowing of digital divide and convergence of ICT in all three technologies for both total group and subgroups. The digital gap was narrowing over time and the low-income countries were catching up faster to the middle-income countries in all three technologies. However, there are marked differences exhibited in the speed of narrowing digital divide and the speed of convergence between the total groups and the subgroups of countries. Some policy implications were discussed in the conclusion and they can be utilized in designing developmental ICT policies in each technology case for individual countries.

• Journal of Multimedia Information System
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• v.6 no.2
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• pp.107-118
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• 2019

This paper deals with actual optical data from rural as well as urban areas in a nationwide study captured with Fisheye cameras. Simultaneously data was collected (of the receiving power density) from the mobile communications satellite N-STAR. The visibility of the satellite is easily determined by checking the value of the pixels in the binarized fisheye image of its position. The process of determining the visible satellite is automatically performed. Based on the analyses of the field data measured in Japan, we are expecting HEOs (Highly inclined Elliptical Orbiters) that would reduce blockage in the extreme northern region of Wakkanai City well as in the most crowded urban area, in Tokyo Ginza. In case of HEOs operation, the elevation angle will improve from 37 with N-STAR GEO to 75 degrees. HEOs could replace 5G/Ka-band or support in rural areas where broadband circuit is not available. We are proposing combination operations with HEOs and 5G/Ka-band to solve blockage problems, because HEOs can keep line-of-sight propagation with high elevation angle for long duration. In such operations, the communications profile on the vehicle based on actual optical data will be very useful to predict blockages and to select/switch a suitable circuit.

• Journal of Information Processing Systems
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• v.16 no.6
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• pp.1459-1478
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• 2020

In the last few years, quantum communication technology and services have been developing in various advanced applications to secure the sharing of information from one device to another. It is a classical commercial medium, where several Internet of Things (IoT) devices are connected to information communication technology (ICT) and can communicate the information through quantum systems. Digital communications for future networks face various challenges, including data traffic, low latency, deployment of high-broadband, security, and privacy. Quantum communication, quantum sensors, quantum computing are the solutions to address these issues, as mentioned above. The secure transaction of data is the foremost essential needs for smart advanced applications in the future. In this paper, we proposed a quantum communication model system for future ICT and methodological flow. We show how to use blockchain in quantum computing and quantum cryptography to provide security and privacy in recent information sharing. We also discuss the latest global research trends for quantum communication technology in several countries, including the United States, Canada, the United Kingdom, Korea, and others. Finally, we discuss some open research challenges for quantum communication technology in various areas, including quantum internet and quantum computing.

• Journal of the Korea Society of Computer and Information
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• v.27 no.1
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• pp.33-41
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• 2022

This paper describes a planar microstrip patch antenna designed on dielectric substrate. Two types of planar microstrip patch antennas are studied for the 5G wireless applications, one type is conventional microstrip structure, the other type is stacked microstrip structure fed by coaxial probe. Using electromagnetically coupling method, stacked microstrip patch antenna employing a multi-layer substrate structure was designed. The results indicate that the proposed stacked microstrip patch antenna performs well at 5G wireless service bandwith a broadband from 3.42GHz to 3.70GHz. The impedance bandwidth(VSWR≤2) is 360MHz(10.28%) from 3.42GHz to 3.78GHz. In this paper, through the designing of a stacked microstrip patch antenna, we have presented the availability for 5G wireless repeater system.

• Korean Journal of Remote Sensing
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• v.38 no.1
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• pp.45-56
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• 2022

The Ieodo Ocean Research Station (IORS) lies between the exclusive economic zone (EEZ) boundaries of Korea, Japan, and China. The geographical positioning of the IORS makes it ideal for monitoring ships in the area. In this study, we introduce ship monitoring results by Automatic Identification System (AIS) and the Broadband 3G^TM radar, which has been developed for use in small ships using the Frequency Modulated Continuous Wave (FMCW) technique. AIS and FMCW radar data were collected at IORS from November 23th to 30th, 2013. The acquired FMCW radar data was converted to 2-D binary image format over pre-processing, including the internal and external noise filtering. The ship positions detected by FMCW radar images were passed into a tracking algorithm. We then compared the detection and tracking results from FMCW radar with AIS information and found that they were relatively well matched. Tracking performance is especially good when ships are across from each other. The results also show good monitoring capability for small fishing ships, even those not equipped with AIS or with a dysfunctional AIS.

• Advances in aircraft and spacecraft science
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• v.9 no.6
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• pp.525-536
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• 2022

The current state of telecommunications infrastructure in the Arctic does not allow providing a wide range of required services for people, businesses and other categories, which necessitates the use of non-traditional approaches to its organization. The paper proposes an innovative approach to building a combined communication network based on tethered high-altitude platform station (HAPS) located at an altitude of 1-7 km and connected via radio channels with terrestrial and satellite communication networks. Network configuration and composition of telecommunication equipment placed on HAPS and located on the terrestrial and satellite segment of the network was justified. The availability of modern equipment and the distributed structure of such an integrated network will allow, unlike existing networks (Iridium, Gonets, etc.), to organize personal mobile communications, data transmission and broadband Internet up to 100 Mbps access for mobile and fixed subscribers, rapid transmission of information from Internet of Things (IoT) sensors and unmanned aerial vehicles (UAV). A substantiation of the possibility of achieving high network capacity in various paths is presented: inter-platform radio links, subscriber radio links, HAPS feeder lines - terrestrial network gateway, HAPS radio links - satellite retransmitter (SR), etc. The economic efficiency of the proposed solution is assessed.

• Journal of Korea Society of Digital Industry and Information Management
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• v.5 no.3
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• pp.175-184
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• 2009

We are entering into a era of enterprise computing that is characterized by an emphasis on broadband convergence, knowledge s haring, and calm services. Some people refer to this as the "ubiquitous" computing because its focus is on a high degree of connectivity between a company and its customers, suppliers, and channel partners. Ubiquitous computing technology, "RF" stands for "radio frequency"; the "ID" means "identifer". The tag itself of a computer chip and an antenna. The shortest metaphor is that RFID is like a bar-code but is read with an electromagnetic field rather than by a laser beam. Much has already been written about the use of RFID. But there is no has written about the use of RFID in the convention industry. Therefore this study have specific objectives as follows. 1. To give details on the use of RFID in convention. 2. To introduces the key concepts behind RFID technology. 3. To identify advantage & disadvantage of RFID technology using a BEXCO CASE study. 4. To study on ubiquitous convention using RFID and effective operation methods such as entrance identification system, session management, machine management, CRM management, visitor management, and contents management. This results provide into the current status of ubiquitous computing technology in convention industries. Specific advantages by using ubiquitous computing technology(RFID) are one-stop differentiate service, wireless internet service, use of visitor management system, entrance by tag, and U-logistics. On other side, disadvantages are security, stabilization of RFID system, higher price of RFID tag, and commercial scale. Convention by using of RFID technology is currently at an early stage. Convention company as BEXCO need to have the capabilities to adapt, to customize, to commercialize, and to modify technology to suit our circumstances.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2014.06a
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• pp.144-145
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• 2014

IoT (Internet of Things) is connected to all things Internet-based people and things, things and objects that communicate information between said intelligent technologies and services. Shipping each of a variety of devices that act independently from each other, but, it is actively interlock with each other is not easy practically days. Ship it within the means of communication, the communication between the ship, the communication between ship and shore configuration, SAN (Ship Area Network), RFID/USN, broadband communications, satellite communications and IT technology to a variety of marine environments for the safe navigation the ship's safety management system for the configuration you want to discuss the plan.

• Economic and Environmental Geology
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• v.31 no.1
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• pp.53-57
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• 1998

Transient electromagnetic (TEM) method is also affected by cultural and natural electromagnetic (EM) noises, since it uses part of the broadband ($10^{-2}$ to $10^5Hz$) spectrum. Especially, predominant EM noise which affects a moving transmitter-receiver TEM system is sensor motion-induced noise. This noise is caused by the sensor motion in the earth magnetic field. The technique for reducing the sensor motion-induced EM noise presented in this paper is based on Halverson stacking. This Halverson stacking is generally used in a time-domain induced polarisation (IP) system to reject DC offset and linear drift. According to spectrum analysis of the vertical component of sensor motion-induced noise, the frequency range affected by the motion of an EM sensor is less than about 700 Hz in this study. With the decrease of the frequency, the spectral power caused by the motion of a sensor increases. For example, at the frequency of 200 Hz, the spectral power of the sensor motion-induced noise is $-90dBVrms^2$ while the spectral power of the EM noise measured with a fixed sensor on the ground is $-105dBVrms^2$, and at the frequency of 100 Hz, the spectral power of the sensor motion-induced noise is $-70dBVrms^2$ while the spectral power of the EM noise measured with a fixed sensor on the ground is $-105dBVrms^2$. With applying Halverson stacking to an artificial noise transient generated by adding a noise-free transient to sensor motion-induced noise measured without pulsing, it is shown that the filtered transient is nearly consistent with the noise-free transient within a delay time of $0.5{{\mu}sec}$. The inversion obtained from this filtered transient is in accord with the true model with an error of 5%.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.31 no.8
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• pp.44-49
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• 2003

In case of an extrinsic Fabry-Perot interferometric sensor, the phase compensating technique is particularly necessary in applying the interferometer to detecting acoustic emission signals because of signal-fading problems. The technique makes it possible to maintain the phase at the quadrature point. In this paper, we developed the stabilization control sensor system that is composed of a broadband light source, a tunable Fabry-Perot (F-P) filter and a control-circuit board. A tension test of a composite specimen was performed to verify if the developed system could compensate the phase change induced from the tension strain and keep the phase at the quadrature point.