• Journal of the Korean Society for Railway
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• v.19 no.4
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• pp.456-467
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• 2016

Wireless Access in Vehicular Environments (WAVE) communication technology, which provides vehicleto-vehicle and vehicle-to-infrastructure communication and offers safe and convenient service, has been developed for application to an Intelligent Transport System (ITS). This paper provides field test results on a study of the feasibility of WAVE technology application to railway communication systems. A test railway communication system based on WAVE technology has been built along the Daebul line and a newly developed EMU. Field tests have been carried out according to the communication function requirements for LTE - R. The test results show that the railway communication system based on WAVE technology meets the functional requirements: maximum transmission length is 730m, maximum transfer delay is 5.69ms, and maximum interruption time is 1.36s; other tests including throughput test, video data transmission test, VoIP data test, and channel switching test also produced results that meets the functional requirements. These results suggest that WAVE technology can be applied to the railway communication system, enabling Vehicle-to-Wayside communication.

• Journal of Korean Tunnelling and Underground Space Association
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• v.24 no.6
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• pp.745-756
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• 2022

The road tunnel is a semi-closed space that is blocked on all sides except the entrance and exit, and in the event of a fire, the smoke of the fire spreads longitudinally due to heat buoyancy caused by the fire and air currents that always exist in the tunnel. To solve this problem, smoke removal facilities are installed in road tunnels to secure a safe evacuation environment by controlling the direction of movement of smoke or directly smoking at fire points. In urban areas, the service level of urban roads decreases due to the increase in traffic due to the increase in population, and as a solution, the construction of underground roads in urban areas is increasing. When a fire occurs during hydrogen leakage through TPRD of a hydrogen fuel cell vehicle (FCEV), the fire intensity depends on the amount of leakage, and the maximum fire intensity depends on the orifice diameter of the TPRD. Considering the TPRD orifice diameter of 1.8 mm, this study analyzed the diffusion distance of fire smoke according to the wind speed of the roadway and the opening interval of the large exhaust port when the maximum fire intensity was 15 MW. As a result, it was analyzed that air flow in the tunnel could be controlled if the wind speed of the road in the tunnel was less than 1.25 m/s, and smoke could be controlled within 200 m from the fire if the damper interval was 50 m and 100 m.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.31 no.4
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• pp.731-751
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• 2021

The Internet of Things is a huge group of devices communicating each other and the interconnection of objects in the network is a basic requirement. Choosing a reliable device is critical because malicious devices can compromise networks and services. However, it is difficult to create a trust management model due to the mobility and resource constraints of IoT devices. For the centralized approach, there are issues of single point of failure and resource expansion and for the distributed approach, it allows to expand network without additional equipment by interconnecting each other, but it has limitations in data exchange and storage with limited resources and is difficult to ensure consistency. Recently, trust management models using fog nodes and blockchain have been proposed. However, blockchain has problems of low throughput and delay. Therefore, in this paper, a trust management model for selecting reliable devices in a fog-based IoT environment is proposed by applying IOTA, a blockchain technology for the Internet of Things. In this model, Directed Acyclic Graph-based ledger structure manages trust data without falsification and improves the low throughput and scalability problems of blockchain.

• The Journal of the Korea Contents Association
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• v.18 no.12
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• pp.140-149
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• 2018

Along with the recent increase in national income, social phenomena such as aging due to a decrease in population and an increase in single households are observed. There are also an increasing number of households raising pets in proportion to aging households and the increase in the number of single households, most of which use animal companions to overcome loneliness and boost domestic vitality. As more and more people consider pets as family members, the size of the domestic pet market is also growing. The growing number of pets in older households and single households is not properly managed by care such as food meals and exercise management for pets. It is necessary to research and develop robots that can monitor animal companions remotely, feed a certain amount of food at regular intervals, and manage their health through exercise. Among pet companions, dog selection is the highest. Therefore, this study identified robot research on driving methods, examples of existing pet care systems, and researched pet care robots using obstacle avoidance algorithms. In order to use the snack pay behavior and obstacle avoidance algorithm of the pet animals by applying IoT and we .oPI technology, it is able to use ultrasonic sensors on the front and has four infrared sensors on the back. However, this study does not reflect the characteristics of other pet animals as a study on pet care robots, and it requires continuous observation and testing.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.11 no.6
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• pp.757-763
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• 2018

It is very difficult to achieve sufficient data rate and required quality of service due to the time-varying nature of the radio channel and various jammers such as path loss, delay, Doppler, shadowing and interference. Especially, the propagation path between the transmitting antenna and the tracking antenna mounted on the fuselage during the test and evaluation of the projectile system considered in this paper is based on the rapid movement of the projectile, the interference due to multipath fading due to the terrain, The propagation path may be blocked. In order to effectively improve the multipath fading occurring in the wireless communication system, a diversity combiner technique is required. In this paper, to derive the design and improvement schemes for the space diversity combiner technique among the diversity combiner schemes, the BER performance of maximum ratio combining (MRC) and selection combining (SC) In an adaptive SC / MRC diversity combiner that operates with MRC when it is lower than the specified threshold criterion when comparing the SNR between two signals received from the channel and operates with SC at high and combines the two received signals The BER performance of the system was compared and analyzed.

• 재활복지
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• v.21 no.2
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• pp.63-88
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• 2017

This study evaluated the actual status of special needs of the hearing-impaired person for disaster response. The analysis revealed a significant level of unmet needs in disaster response for hearing-impaired person. The 5 special needs in disaster response include: 1) communication needs, which involve securing the means to make an emergency rescue request and communicating information during the rescue process; 2) transportation needs, which indicate the effective evacuation capacity and the level of training; 3) medical needs, which address the degree of preparedness for physical and mental emergency measures and the delivery of health information for rescue and first aid process; 4) maintaining functional independence needs, which refer to the level of self-preparedness to minimize damage in disaster situations, and; 5) supervision needs, which correspond to a personalized support system provided to disaster-vulnerable groups.

• Journal of Climate Change Research
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• v.6 no.4
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• pp.291-302
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• 2015

Vulnerability due to climate change depends on the concentration of carbon dioxide emissions over several upcoming decades. The objective of this study is to estimate the concentration of greenhouse gases and air pollutants in 2100, while also accounting for expected socio-economic changes in Korea. First, we intend to prepare scenarios for possible socioeconomic changes in Korea: business as usual (BAU), high growth and low growth. Secondly, we aim to predict services demands in residential?commercial sector, transportation sector, industrial sector for each scenarios. Finally, the emissions of LLGHG and SLCP will be estimated on the basis of the predicted service demands. The study results project that in Korea, LLGHG emissions will be approximately $660Mt\;CO_2\;eq$. and SLCP emissions will be approximately 3.81 Mt, -including black carbon (BC) by 2100. The transportation and industrial sectors are the major source for LLGHG emissions, and the residential and commercial sector serve as the SLCP source. Later, additional studies on the cost and benefit of mitigation should be carried out by comparing the reduced use of materials that cause climate change as a result of reduction policies and the socioeconomic cost.

• Journal of the Korean Association of Geographic Information Studies
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• v.21 no.4
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• pp.132-144
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• 2018

3D Geo-spatial information models have been widely used in the field of Civil Engineering, Medical, Computer Graphics, Urban Management and many other. Especially, in surveying and geo-spatial field, the demand for high quality 3D geospatial information and indoor spatial information is so highly increasing. However, it is so difficult to provide a low-cost and high efficiency service to the field which demand the highest quality of 3D model, because pre-constructed spatial data are composed of different formats and storage structures according to the application purpose of each institutes. In fact, the techniques to construct a high applicable 3D geo-spatial model is very expensive to collect and analyze geo-spatial data, but most demanders of 3D geo-spatial model never want to pay the high-cost to that. This study, therefore, suggest the effective way to construct 3D geo-spatial model with low-cost of construction. In general, the effective way to reduce the cost of constructing 3D geo-spatial model as presented in previous studies is to combine the raw data obtained from point cloud observatory and UAV imagery, however this method has some limitation of usage from difficulties to approve the use of raw data because of those have been managed separately by various institutes. To solve this problem, we developed the linking & management system for unifying a high-Resolution raw geo-spatial data based on the point cloud DB and apply this system to extract the basic database from 3D geo-spatial mode for the road database registration. As a result of this study, it can be provided six contents of main entries for road registration by applying the developed system based on the point cloud DB.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.37 no.4
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• pp.253-265
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• 2019

In this study were analyzed the errors on the registration of details information, location of E-GEN (Emergency medical-GEN) AED (Automated External Defibrillator) installation site and the adequacy of spatial arrangement, which suggests an improvement methods of constructing an app or web based on time and space data for efficient operation of considering accessibility and usability. As a result of this study, first, it was not equal to each other for locations of each installation point of AED, that confirmed some area were dense or requiring additional installation. Second, it confirmed the inaccuracies in inputting and registering information about the installed location, such as the actual installation location information and the attribute information of the AED. Third, the main access node and the main address node were connected to a straight line that was found not be connected to the back door, the straight line, the stairs. Also, the opening times of AED installation sites varied according to the week and the season, the entrance was managed by the apartment management office in a separate place, it needs to be established on this information. In conclusion, it proposed a method to improve spatial equity and accessibility, a method to provide accurate distance and time according to actual movement routes in case of emergency, and a possibility of using each facility considering day and time.

• Journal of IKEEE
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• v.23 no.1
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• pp.280-288
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• 2019

In the CR-enabled MANET, routing paths can be easily destroyed due to node mobility and channel unavailability (due to the emergence of the PU of a channel), resulting in significant overhead to maintain/recover the routing path. In this paper, network caching is actively used for route maintenance, taking into account the properties of the CR. In the proposed scheme, even if a node detects that a path becomes unavailable, it does not generate control messages to establish an alternative path. Instead, the node stores the packets in its local cache and 1) waits for a certain amount of time for the PU to disappear; 2) waits for a little longer while overhearing messages from other flow; 3) after that, the node applies local route recovery process or delay tolerant forwarding strategy. According to the simulation study using the OPNET simulator, it is shown that the proposed scheme successfully reduces the amount of control messages for path recovery and the service latency for the time-sensitive traffic by 13.8% and 45.4%, respectively, compared to the existing scheme. Nevertheless, the delivery ratio of the time-insensitive traffic is improved 14.5% in the proposed scheme.