• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.34 no.4
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• pp.33-39
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• 2006

In this paper, the collision avoidance of Unmanned Aerial Vehicles(UAVs) by applying the Traffic alert and Collision Avoidance System II(TCAS-II) is introduced. The performances of two UAVs whose maximum vertical rates are different each other are compared and analysed by not only converting many TCAS-II commands into an autopilot input but also implementing a computer program based on the Minimum Operational Performance Standards for TCAS-II. As the alternative to a possible Near Mid-Air Collision for UAVs whose maximum vertical rates are low, we have proposed a modified algorithm considering the maximum vertical rate and altitude. The modified algorithm is available on the assumption that a wider surveillance range is provided by a ADS-B system.

• Convergence Security Journal
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• v.5 no.4
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• pp.67-72
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• 2005

The exponential increase of malicious and criminal activities in cyber space is posing serious threat which could destabilize the foundation of modern information society. In particular, unexpected network paralysis or break-down created by the spread of malicious traffic could cause confusion and disorder in a nationwide scale, and unless effective countermeasures against such unexpected attacks are formulated in time, this could develop into a catastrophic condition. In order to solve a same problem, this paper researched early detection techniques for only early warning of cyber threats with separate way the detection due to and existing security equipment from the large network. It researched the cyber example alert system which applies the module of based honeynet from the actual large network and this technique against the malignant traffic how many probably it will be able to dispose effectively from large network.

• Journal of the Society of Disaster Information
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• v.17 no.3
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• pp.500-511
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• 2021

Purpose: This study seeks to draw out implications that must be considered in the process of establishing measures to evacuate residents in preparation for domestic nuclear disasters by conducting an investigation about the disaster situation at the time of the Fukushima nuclear power plant explosion, emergency warning situation for residents protection, evacuation situation and In addition to investigating problems and measures raised in the resident protection system at that time. Method: A literature survey was conducted focusing on reports published by Japan's national, parliament, local governments and related agencies from right after the Great East Japan Earthquake to the present. Result: Found out what needs to be considered in the process of establishing domestic radiation disaster measures through the results of the survey on the problems and countermeasures derived from the process of evacuation of residents at the time of the Fukushima nuclear power plant explosion. Conclusion: The reviews were classified into four categories and detailed reviews were presented.

• The Journal of the Korea institute of electronic communication sciences
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• v.16 no.5
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• pp.817-824
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• 2021

The SDN(Software Defined Networking) technology, which appeared to overcome the limitations of the existing network system, resolves the rigidity of the existing system through the separation of HW and SW in network equipment. These characteristics of SDN provide wide scalability beyond hardware-oriented network equipment, and provide flexible load balancing policies in data centers of various sizes. In the meantime, many studies have been conducted to apply the advantages of SDN to data centers and have shown their effectiveness. The method mainly used in previous studies was to periodically check the server load and perform load balancing based on this. In this method, the more the number of servers and the shorter the server load check cycle, the more traffic increases. In this paper, we propose a new load balancing technique that can eliminate unnecessary traffic and manage server resources more efficiently by reporting to the controller when a specific level of load occurs in the server to solve this limitation.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.22 no.1
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• pp.171-179
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• 2022

This paper introduces a monitoring and tracking system for corona19 confirmed patients based on the collected data by installing a device that can manage the access list at the entrance to each building on the campus. The existing QR-based electronic access list can't measure the temperature of the person entering the building and it is inconvenient that members have to scan their QR codes with a smartphone. In addition, when the state manages information about confirmed patients and contacts on campus, it is not easy for members to quickly share and track information. These could lead to cases where a person is in close contact with an infected person developing another patient. Therefore, this paper introduces a device using face recognition library and a temperature sensor installed at the entrance of each building on the campus, enabling the administrator to monitor the access status and quickly track members of each building in real-time.

• Atmosphere
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• v.33 no.3
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• pp.319-330
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• 2023

As the need for PM type observation increases, Surface Particulate Matter Network (SPARTAN), PM samplers analyzes aerosol samples for PM mass concentration and chemical composition, were recently installed at two sites: Yonsei University at Seoul and Ulsan Institute of Science and Technology (UNIST) at Ulsan. These SPARTAN filter samplers and nephelometers provide the PM_2.5 mass concentration and chemical speciation data with aerosol type information. We introduced the overall information and installation of SPARTAN at the field site in this study. After installation and observation, both Seoul and Ulsan sites showed a similar time series pattern with the daily PM_2.5 mass concentration of SPARTAN and the data of Airkorea. In particular, in the case of high concentrations of fine particles, daily average value of PM_2.5 was relatively well-matched. During the Yonsei University observation period, high concentrations were displayed in the order of sulfate, black carbon (BC), ammonium, and calcium ions on most measurement days. The case in which the concentration of nitrate ions showed significant value was confirmed as the period during which the fine dust alert was issued. From the data analysis, SPARTAN data can be analyzed in conjunction with the existing urban monitoring network, and it is expected to have a synergetic effect in the research field. Additionally, the possibility of being analyzed with optical data such as AERONET is presented. In addition, the method of installing and operating SPARTAN has been described in detail, which is expected to help set the stage for the observation system in the future.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.24 no.3
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• pp.163-169
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• 2024

Anti-drone (anti-drone) is at the center of the debate over the failure to shoot down a North Korean drone that invaded the metropolitan area at the end of 2022. Anti-drone is a means of detecting and restraining drone flights in unauthorized airspace. Anti-drone technology is a key defense system for drone technology that is essential in the current illegal situation of various drones. We must be alert in the war in Ukraine, where the role of drones has increased. Drone attacks, which are not easy to defend, may determine the victory or defeat of the war. Competition for anti-drone technology development in countries around the world will rise. When new anti-drone technology emerges, drones that go beyond it will be developed. This study presented the current status of anti-drone by analyzing the defense system of domestic drones.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.24 no.5
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• pp.1-7
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• 2024

This paper presents the design and implementation of a VPN (Virtual Private Network) module to address the need for external access and functional expansion of NVR (Network Video Recorder) systems. NVR systems play a critical role in enhancing security across various industries through real-time monitoring and recording. However, they are vulnerable to security threats, particularly when a secure connection to external networks is required. To resolve this issue, this study applied a VPN module to ensure that NVR systems can communicate securely with external networks. This approach enabled remote access and real-time event notifications. Performance tests confirmed 100% accuracy in event notifications. This research contributes to improving the security and operational efficiency of NVR systems, highlighting the necessity and utility of VPN modules for secure communication with external networks.

• International conference on construction engineering and project management
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• 2009.05a
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• pp.869-875
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• 2009

Safety is a big issue in the construction sites. For safe and secure management, tracking locations of construction resources such as labors, materials, machineries, vehicles and so on is important. The materials, machineries and vehicles could be controlled by computer, whereas the movement of labors does not have fixed pattern. So, the location and movement of labors need to be monitored continuously for safety. In general, Global Positioning System(GPS) is an opt solution to obtain the location information in outside environments. But it cannot be used for indoor locations as it requires a clear Line-Of-Sight(LOS) to satellites Therefore, indoor location monitoring system could be a convenient alternative for environments such as tunnel and indoor building construction sites. This paper presents a case study to investigate feasibility of Wi-Fi based indoor location monitoring system in construction site. The system is developed by using fingerprint map of gathering Received Signal Strength Indication(RSSI) from each Access Point(AP). The signal information is gathered by Radio Frequency Identification (RFID) tags, which are attached on a helmet of labors to track their locations, and is sent to server computer. Experiments were conducted in a shield tunnel construction site at Guangzhou, China. This study consists of three phases as follows: First, we have a tracking test in entrance area of tunnel construction site. This experiment was performed to find the effective geometry of APs installation. The geometry of APs installation was changed for finding effective locations, and the experiment was performed using one and more tags. Second, APs were separated into two groups, and they were connected with LAN cable in tunnel construction site. The purpose of this experiment was to check the validity of group separating strategy. One group was installed around the entrance and the other one was installed inside the tunnel. Finally, we installed the system inner area of tunnel, boring machine area, and checked the performance with varying conditions (the presence of obstacles such as train, worker, and so on). Accuracy of this study was calculated from the data, which was collected at some known points. Experimental results showed that WiFi-based indoor location system has a level of accuracy of a few meters in tunnel construction site. From the results, it is inferred that the location tracking system can track the approximate location of labors in the construction site. It is able to alert the labors when they are closer to dangerous zones like poisonous region or cave-in..

• Journal of Cadastre & Land InformatiX
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• v.49 no.2
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• pp.123-134
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• 2019

The introduction of the world geodetic reference system in cadastral sector can apply the international standardization of cadastral survey and can be the basis for the creation of new industries by merging with other industries based on spatial information. With the introduction of the world geodetic reference system, non-coincidence land may cause problems which are whether the cadastral record and the real estate register are not consistent, etc. This problem infringes on the protection of ownership of citizens suggested in the main purpose of ｢Act On The Establishment, Management, Etc. Of Spatial Data｣. We have analyzed at overlapping cases between private land and overlapping cases between national and public land and suggested institutional improvement measures to solve problems arising on the site. As a result, it will be necessary to introduce a transformation verification measure by the world geodetic reference system in order to assign a function as a cadastral records to mapping converted to the world geodetic reference system. It is also expected that the legal and institutional basis should be established for alert adjustment and positioning through verification measures. Finally, it is difficult to determine the transformation factor as the co-ordinates of common points also differ because survey results vary by work area. Therefore, it is deemed necessary to consider the requirement to use the cadastral measurement basis by the world geodetic reference system in 2021.