• The Journal of the Korea institute of electronic communication sciences
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• v.17 no.5
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• pp.815-824
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• 2022

The growing integration of intermittent renewable sources like offshore wind energy increases the need for transferring electric energy over long distances, which may include sea crossings. One of the solutions available for bulk electric power transmission across large distances encompassing wide and deep sea is using HVDC submarine power cables. However, there are no standards or research related to the calculation of the continuous allowable current with various ocean conditions of a DC power cable that does not have an alternating magnetic field. In this study, assuming the typical two types of subsea cable models and two areas of the south coast and the west coast marine conditions, a continuous allowable current simulation of DC cables was performed. As a simulation result, the DC cable continuous allowable current find out the gradient reduction characteristics based on subsea base depth.

• Journal of Sensor Science and Technology
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• v.31 no.2
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• pp.90-95
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• 2022

The effect of the structure of an ITO nanoparticle film sensor on its performance was studied. A printed ITO film (P-ITO film) was fabricated on a flexible polyethylene terephthalate (PET) substrate, and the contact resistance of the electrode and sensor response change were clarified according to the detection position. The contact resistance between Ag and P-ITO was observed to be -204.4 Ω using the transmission line method (TLM), confirming that a very good ohmic contact is possible. In addition, we confirmed that the contact position of the analyte had a significant influence on the response of the sensor. Based on these results, the performance of the four types of sensors was compared. Consequently, we observed that 1) optimizing the resistance of the printed film, 2) optimizing the electrode structure and analyte input position, and 3) optimizing the electrode area are very important for fabricating a metal oxide nanoparticle (MONP) sensor with optimal performance.

• Korean Journal of Remote Sensing
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• v.38 no.4
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• pp.343-353
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• 2022

An attempt to derive the surface temperature from the Korea Multi-purpose Satellite (KOMPSAT)-3A mid-wave infrared (MWIR) data acquired over the southern California on Nov. 14, 2015 has been made using the MODerate resolution atmospheric TRANsmission (MODTRAN) radiative transfer model. Since after the successful launch on March 25, 2015, the KOMPSAT-3A spacecraft and its two payload instruments - the high-resolution multispectral optical sensor and the scanner infrared imaging system (SIIS) - continue to operate properly. SIIS uses the MWIR spectral band of 3.3-5.2 ㎛ for data acquisition. As input data for the realistic simulation of the KOMPSAT-3A SIIS imaging conditions in the MODTRAN model, we used the National Centers for Environmental Prediction (NCEP) atmospheric profiles, the KOMPSAT-3Asensor response function, the solar and line-of-sight geometry, and the University of Wisconsin emissivity database. The land cover type of the study area includes water,sand, and agricultural (vegetated) land located in the southern California. Results of surface temperature showed the reasonable geographical pattern over water, sand, and agricultural land. It is however worthwhile to note that the surface temperature pattern does not resemble the top-of-atmosphere (TOA) radiance counterpart. This is because MWIR TOA radiances consist of both shortwave (0.2-5 ㎛) and longwave (5-50 ㎛) components and the surface temperature depends solely upon the surface emitted radiance of longwave components. We found in our case that the shortwave surface reflection primarily causes the difference of geographical pattern between surface temperature and TOA radiance. Validation of the surface temperature for this study is practically difficult to perform due to the lack of ground truth data. We therefore made simple comparisons with two datasets over Salton Sea: National Aeronautics and Space Administration (NASA) Jet Propulsion Laboratory (JPL) field data and Salton Sea data. The current estimate differs with these datasets by 2.2 K and 1.4 K, respectively, though it seems not possible to quantify factors causing such differences.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.17 no.2
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• pp.369-390
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• 2023

Technologies for disaster management are highly sought areas for research and commercial deployment. Landslides, Flood, cyclones, earthquakes, forest fires and road/train accidents are some causes of disasters. Capturing video and accessing data in real time from the disaster site can help first responders make split second decisions which may save human lives and valuable resource destructions. In this context the communication technologies performing the task should have high bandwidth and low latency which only 5G can deliver. But unfortunately in India, deployment of the 5G mobile communication systems is yet to give a shape and again in remote areas unavailability of 4G signals is still severe. In this situation the authors have proposed, simulated and experimented a 4G-5G communication scheme where from the disaster site the signals will be transmitted by a 5G terminal to a nearby 4G-5G gateway installed in a mobile vehicle. The received 5G signal will be further relayed by the 4G-5G gateway to the fixed 4G base station for onward transmission towards the disaster management station for decision making, deployment and relief monitoring. The 4G-5G gateway acts as a relay and converter of 5G signal to 4G signal and vice versa. This relayed system can be further mounted on a vehicle mounted relay (VMR) as proposed by 3GPP in Release 18. The scheme is also in the same line of context with Verizon's, "Tactical Humanitarian Operations Response" (THOR) vehicle concept. The performance of the link is studied in different channel conditions, the throughput achieved is superb. The authors have implemented the above mentioned system towards smart campus networking and monitoring landslides activities which are common in their regions.

• Proceedings of the IEEK Conference
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• 1998.06a
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• pp.54-57
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• 1998

As the physical layer on telecommunication network is replaced fiber optic lines, it is increased the need of systematic maintenance for fiber optic lines. Korea Telecom has developed FLOMS in order to establish maintenance processes for optical fiber lines. FLOMS has functions which manages optical facilities and tests optical fiber lines automatically. As a resuls, this system can check and/or report a fault. Operator, who is reponsible for management of optical fiber lines, can test the characteristics of optical fiber lines remotely using FLOMS. As interpoerable with Digital Transmission Management System, FLOMS provides efficient management for optical fiber lines. This system improves the work process to find fault location fast, detect the degradation of fiber quality, and make database of optical facilities efficiently.

• Journal of Digital Convergence
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• v.20 no.3
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• pp.389-397
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• 2022

As increasing the growth of the Internet in medical area, a new technology to transmit effectively massive medical data is required. In optical internet, all OBS nodes have fiber delay lines, hardware components. These components are calculated under some optimal traffic conditions, and this means that if the conditions change, then the components should be altered. Therefore, in this article a new service differentiation algorithm using the previously installed components is proposed, which is used although the conditions vary. When traffic conditions change, the algorithm dynamically recalculates the threshold value used to decide the length of data bursts. By doing so, irrelevant to changes, the algorithm can maintain the service differentiation between classes without replacing any fiber delay lines. With the algorithm, loss sensitive medical data can be transferred well.

• Convergence Security Journal
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• v.23 no.2
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• pp.75-84
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• 2023

Recently, as the use of drones for military purposes is increasing, such as the Russia-Ukraine War, North Korea's reconnaissance against South Korea, and Army Tiger 4.0's dronebot system, anti-drone technology is developing a lot in each country. However, traditional anti-drone technologies in the form of using conventional weapons or electronic warfare weapons have the disadvantage of being expensive, so anti-drone technologies that can be performed at low cost are currently being newly researched. Therfore, in response to these anti-drone technologies, many efforts are being made to increase the survivability of our allies. In line with this trend, this study assumes a virtual anti-drone system applied with cyber domain and electronic warfare domain technologies that can be performed at low cost, rather than a technique using expensive conventional weapons or electronic warfare weapons among various anti-drone technologies. In response to this, we would like to present a plan to increase the survivability of friendly drones.

• Journal of IKEEE
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• v.27 no.4
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• pp.601-609
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• 2023

In this paper, we propose an artificial intelligence-based high-speed fault diagnosis method using an FPGA in the event of a ground fault in a DC system. When applying artificial intelligence algorithms to fault diagnosis, a substantial amount of computation and real-time data processing are required. By employing an FPGA with AI-based high-speed fault diagnosis, the DC breaker can operate more rapidly, thereby reducing the breaking capacity of the DC breaker. therefore, in this paper, an intelligent high-speed diagnosis algorithm was implemented by collecting fault data through fault simulation of a DC system using Matlab/Simulink. Subsequently, the proposed intelligent high-speed fault diagnosis algorithm was applied to the FPGA, and performance verification was conducted.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.23 no.6
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• pp.157-162
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• 2023

A highly sensitive refractive index bio-sensor based on grating-assisted strip directional coupler (GASDC) is proposed. The sensor is designed using two asymmetric strip waveguides with a top-loaded grating structure in one of the waveguides. Maximum light couples from one waveguide to the other at the resonance wavelength satisfying phase-matching condition (PMC), and it shows that the change in phase-matching condition with the change in refractive index of the analyte medium in the cover region can be used as a measure of the sensitivity. The proposed sensor will be an on-chip device with a high refractive index sensitivity, and the sensor configuration offers a low propagation loss, thereby enhancing the sensitivity. Furthermore, variation of the sensitivity with the waveguide parameters of sensor is evaluated to optimize the design.

• (The) Research of the performance art and culture
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• no.36
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• pp.751-781
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• 2018

Task of circling the pagoda of Waljeongsa(Woljeongsa Tabdori) is the major intangible cultural heritage with representativeness and historical meaning as a Buddhism culture, one of the Buddhism folk plays, which was firstly played after the liberation. Woljeongsa Tabdori holds significant designation importance in terms of Buddhism folklore heritage with Korean unique tradition and identity of Gangwon-do province. Temples are demonstrating Tabdori nationwide but Woljeongsa Tabdori is the unique case that systematically inherits the culture based on the designation of being intangible cultural heritage. That is why it is needed to focus on the cultural and internal value of Woljeongsa Tabdori. Tabdori is the integrated symbol of Buddhism respect and worship to the Buddha and pagoda. It is hard to presume the originality of Woljeongsa Tabdori: given the history of Woljeonsa temple, it lies into Goguryeo traditional play and Bokhui(Pagoda circling folk play) in Silla era. It fits into the courtesy of Circumambulating Stupa considering Moon in Goguryo mural, background of Odaesan Hwaeom thought/tripitaka and essence of Octagonal 9-story stone pagoda. At the first stage of Tabdori, Buddhist musical instruments such as Buddhism temple bell, singing bowl, cloud-shaped gong and wooden-fish. However, later, Samhyeon Yukgak has been added and then, Boyeom and Bakpaljeongjinga were singing: it could be interpreted that it was a pure Buddhist ceremony but it has become to have traditional aspect and been spread to the public. The origin of Woljeongsa Tabdori is related to the explanation of Circumambulating Stupa that experiences the glory of the ending ceremony. When a temple has a rite, the Buddhists make an offering to the Buddha. At that time, Buddhist prayer, sermon and chant are followed. After the rite, the Buddhists are circling the pagoda with the monks while praying for Buddhist charity and making their own wishes. It prays not only going after death to Nirvana of the one but also national prosperity and the welfare of the people for peaceful reign. As the temple holds bigger rites, many Buddhists gather and the Tabdori was a success. The scene of circling the pagoda and making own wishes in line with the Buddhist sermon was solemn. The idea on changes and convergence of Woljeongsa Tabdori requires strategic inheritance to promote the transmission while maintaining the paragon and purpose of designating the cultural heritage and reviving its identity. Korean Tabdori was held in Buddha's birthday in April and the mid-autumn day. Tabdori is a memorial service type Buddhist ceremony that once the monk holds the Buddhist rosary, circles the pagoda and sings the great mind and charity of the Buddha, Buddhists follow the step, lighting the lantern, circling the pagoda and praying for the gentle and easy death. Transmission education of the successor, diversified approach of the expert's advice and discourse on the revival of the origin should be reinforced in phases.