• Journal of the Korea Institute of Information Security & Cryptology
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• v.17 no.1
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• pp.115-119
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• 2007

The IPv6 protocol provides the method to automatically generate an address of a node without additional operations of administrators, Before the generated address is used, the duplicate address detection (DAD) mechanism is required in order to verify the address. However, during the process of verification of the address, it is possible for a malicious node to send a message with the address which is identical with the generated address, so the address can be considered as previously used one; although the node properly generates an address, the address cannot be used. In this paper, we present a strong scheme to perform the DAD mechanism based on hash functions in IPv6 networks. Using this scheme, many nodes, which frequently join or separate from wireless networks in public domains like airports, terminals, and conference rooms, can effectively generate and verify an address more than the secure neighbor discovery (SEND) mechanism.

• Journal of Internet Computing and Services
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• v.23 no.3
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• pp.57-65
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• 2022

International attempts to smuggle narcotics and explosives using ship or aircraft cargoes are on the rise. With the recent increase in the number of detection cases of narcotics and explosives in Korea, it is important to detect dangerous material (narcotics and explosives) through container searches at ports and airports, which are the main routes. This paper proposes a technique to detect dangerous material in cargo containers using the sampled output signal of ion mobility spectroscopy (IMS). The proposed technique estimates parameters such as a threshold, a window length, and a noise level for ion detection of the target dangerous material by using known materials in the initialization stage. The estimated parameters are used to detect the ions of the dangerous target material inside the containers. The proposed technique can be applied when the peak value of the IMS signal and the ion mobility are varying due to container environments.

• Journal of Advanced Navigation Technology
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• v.26 no.5
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• pp.249-260
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• 2022

Student pilots receiving flight education are inexperienced in piloting and situation judgment skills and are greatly affected by various factors such as psychological, physical, and environmental factors. In particular, one of the most influential factors in the flight education of student pilots is the weather conditions. Unlike large aircraft used in the air transportation business, small aircraft used for flight education have a great impact on education, such as flight restrictions depending on weather conditions, psychological pressure in severe weather, and deterioration of student skills. Therefore, in this study, the meteorological characteristics of meteorological factors that have a great influence on small aircraft were analyzed. As a result of the analysis, an efficient and safe training operation method was suggested to a professional pilot aviation training organization through the adjustment of the training period for the season, the increase in aircraft operation rate, and a safe solo flight plan considering the weather.

• Environmental and Resource Economics Review
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• v.31 no.4
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• pp.571-595
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• 2022

This study theoretically analyzes the cost allocation of replacement costs that occur when existing operators have to replace circuit breakers due to the entry of new generators. We adopt the sequential equal contributions rule as the cost allocation rule, which is widely used in cost allocation problems in cooperative game theory. We derive various cost allocation plans based on several criteria and examine to what extent each alternative meets various desirable axioms. According to the analysis, (i) the alternative that excludes the cost of the new operator, residual value, and network operator and (ii) the alternative that excludes the cost of the new operator, residual value, and includes network operator are relatively superior to other schemes. We also identify a realistic plan by taking into account practical factors and analyze its axiomatic characteristics.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.2D
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• pp.325-333
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• 2006

Recently, in the case of observing the global environment, satellite remote sensing technology has been important. It's because satellite remote sensing is valuable for assessing relatively large areas. But now, small scale remote sensing techniques are needed which can be applicable to the detail investigation of plant tree areas which afforest land after the large scale construction of roads, dams and airports. In this study, we tried to develop and propose a lower altitude sensing technique which can be used in ground remote sensing by using a CCD camera. As a result of this investigation the following can be concluded: We recognized the transference characteristics of filters which were used in comparative tests about the four ground remote sensing devices. We also found that the near-IR camera could be used for an imaging spectral radiometer in the extraction of the vegetation index. Furthermore, we found that the vegetation index has varied hour by hour during the day of the experiment. Finally, we brought about an increase phase of the NDVI in a forest fire, which caused considerable damage, by developing new ground remote sensing technology.

• Journal of Advanced Navigation Technology
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• v.26 no.6
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• pp.393-403
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• 2022

Various studies suggest that the initial operating form of UAM, which is being presented as a solution to the urban traffic problem, will be similar to VTOL aircraft among current aircraft. In a form similar to determining the direction of the runway where fixed-wing aircraft take off and land, the vertiport where take-off and landing of VTOL aircraft takes place determines the flight direction of departure and arrival in consideration of the direction of the wind. Unlike areas where airports are generally built, in the case of downtown areas, it is expected that the characteristics of wind may continuously change depending on the environment of changing terrain or obstacles such as the construction of new buildings. In this study, long-term actual observation data for reviewing the take-off and landing directions at the city center where the location of the vertiport is expected are compared using a wind speed map, and the characteristics of the ground wind and the possibility of change in the direction of the predominant wind depending on the observation period and observation location confirmed.

• Journal of Aerospace System Engineering
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• v.17 no.6
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• pp.46-53
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• 2023

As urban traffic congestion and environmental pollution are becoming significant issues in major cities, Urban Air Mobility (UAM) is gaining attention as an efficient solution. In this study, we conducted a geographic information system (GIS)-based spatial analysis and clustering algorithm considering the actual data of the terrain and infrastructure in the Busan area, through which we were able to select the location of vertiports and corridors (flight routes) for the UAM operation. Based on the Gimhae International Airport, which is expected to be the center of the UAM infrastructure system in the Busan region, we judged that three vertiport locations in the target area were suitable. Subsequently, we used the A^* (A-star) algorithm considering Ground Risk to select a flight path that minimized both risk and distance. Through this, we confirmed a risk reduction effect of 80.168% compared to the minimum distance route.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.23 no.1
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• pp.112-122
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• 2024

Recently, as unmanned aerial vehicle technology such as drones has developed, there are many environmental, social and economic benefits, but if there is malicious intent against important national facilities such as airports, public institutions, power plants, and the military, it can seriously affect national safety and people's lives. It can cause damage. To respond to these drone threats, attempts are being made to introduce detection equipment such as RF scanners. In particular, power transmission towers installed in substations, power plants, and Korea's power system can affect detection performance if the transmission tower is located in the RF scanner detection path. In the experiment, a commercial drone was used to measure the signal intensity emitted from the drone and confirm the attenuation rate. The average and maximum attenuation rates showed similar trends in the 2.4 GHz and 5.8 GHz bands, and were also affected by the density of the structure.

• Journal of Practical Engineering Education
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• v.16 no.5_spc
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• pp.701-708
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• 2024

The challenges of exploring distant locations have become increasingly apparent, especially since COVID-19 has made visiting even nearby museums and attractions more difficult. Various factors contribute to this, including time constraints, financial limitations or language barriers. However, these challenges can be overcome with recent technologies by transforming how users experience and interact with spaces. With the latest advancements, it is now possible to create virtual representations of famous attractions, allowing users to take virtual tours as if they were physically present. This paper presents a comprehensive framework for creating virtual tours using Matterport, a leading 3D scanning technology, and Unity 3D, a powerful game engine. The paper outlines methodologies for capturing 3D data with Matterport, importing it into Unity, enhancing user interaction, and optimizing the overall experience. By integrating these tools, the framework aims to facilitate immersive virtual experiences. This approach will allow affordable virtual tickets for famous attractions around the world which will be great educational opportunities. In addition, this framework can be applicable to facilitate easier navigation in complex environments such as airports and hospitals.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.4 no.3
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• pp.66-74
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• 2001

The main purpose of this thesis is to select the appropriate plants for the ecological restoration of coastal land. The soil and vegetation environment survey of the beach where the halophytes live now was executed for the sake. Firstly, the soil survey was done by the physical and chemical survey of beach soil and dumped soil. The soil is mostly sandy loam and sandy clay loam which has silty much. The beach soil where the salt plants live has more organic matters in the content than dumped soil because of the influx of the dead halophytes, a pioneer plant to this area. Secondly the vegetation survey was executed by the halophytes survey in the beach area in order to select the appropriate plants for ecological restoration. The shows two different areas in the vegetation divided by the salt density of soil. Artemisia fukudo, Juncus haenkei, Carex pumila, Silene armeia, Polyponum aviculare etc live in the less salt density area and it doesnt show collected. Salicornia herbacea, Suaeda asparagoides, Aster tripolium, Limonium tetragonum, Suaeda maritima, Scirus fluvitilis, Phragmtes communis, Suaeda japonica, Zoysia sinica etc halophytes live in the more salt density area and there are a few advent plant but many collected. So the salt density of soil limits the vegetation. The selection of appropriate plants for the ecological restoration programs was designed with 3 different standards considering the salt density of soil in the dumped soil area. The plan selection guidelines of thick salt density due to the salt density of soil, and economical efficiency and maintenance because the area is large. The guidelines of middle salt density area were made considering economical efficiency and maintenance because there are salt as well, and it is effective for the scenery if they have normal ecology but their leaves have good color and the flowers are beautiful. However I suggest beautiful flowery plants for the neutral plan area because this area is the entry point of the airport so the view is very important.