• Journal of the Korean earth science society
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• v.34 no.6
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• pp.536-549
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• 2013

This study investigates the damages of and analyzes the social and economic impacts of volcanic ash eruptions in the world in order to estimate the potential volcanic ash impacts in South Korea when Mt. Baekdusan volcano erupts in the future. First, we build a comparison chart called "the impact of volcanic ash" on each economic and social sector by using major volcanic eruptions and we compare the damage with respect to volcanic ash thickness/weights. Secondly, we analyze the social and economic impact from volcanic ash. The economic damage is not likely to occur in South Korea, unless Mt. Baekdusan erupts in winter. However, the potential damage should not be overlooked because the volcanic ash may have a global impact around the world. If Mt. Baekdusan volcano erupts when the wind blows from north or northeast, the volcanic ash may then significantly affect South Korea of which economy is highly dependent on exports. Particularly when the volcanic ash moves to the densely populated metropolitan areas or agricultural areas, the damage can be significant. In preparation for the potential volcanic disasters, the volcanic ash forecast table suitable for South Korea should be prepared. In addition, building a Korean volcanic ash hazard map in advance will have a strategic significance.

• Journal of Navigation and Port Research
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• v.31 no.8
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• pp.629-635
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• 2007

Reduced crew performance is frequently cited as a major causal factor in maritime accident causation. Although considerable research has been conducted on the hours of work undertaken by seafarers through interviews and the analysis of records, experimental studies to observe the effects of factors such as high workload, shift patterns, stress, sleep deprivation and disturbance on the cognitive performance of mariners have been limited. Other safety-critical transport industries, such as aviation and rail, have developed fatigue management tools to help manage the work patterns of their operators. Such a tool for mariners would assist shipboard crew, marine pilots and shore management in planning and improving work schedules. The overall aim of this paper is to determine a fatigue factor, which can be applied to human performance data, as part of a software program that calculates total cognitive performance. This program enables us to establish the levels of cognitive performance of a group of marine pilots to test a decision-making task based on radar information. This paper addresses one of the factors that may contribute to the determination of various fatigue factors: the effect of different work patterns on the cognitive performance of a marine pilot.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.39 no.6
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• pp.477-483
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• 2015

Investigations into cavity flows have been conducted for noise and vibration problems that arise in cavity systems. Cavity systems have been applied in engineering devices and have undergone rapid development in the aerospace industry. Meanwhile, to the author's best knowledge, the cavity on a curved wall has been seldom studied. The present work is conducted to study the flow physics of a cavity mounted on a curved wall. Numerical analysis is performed to investigate the cavity flow. Two variables of sub- and supersonic cavity flows were considered: the radius of curvature of the curved wall (L/R) and the inlet Mach number. The results show that the uniform vortex generated by the cavity flow on the curved wall stabilize the pressure fluctuation as time passes. As the inlet Mach number increases, the pressure fluctuation amplitude increases. The results obtained from the curved wall are compared with those from a straight wall using Rossiter's formula. The Strouhal number of the curved wall is lower than that of the straight wall. Lower Strouhal numbers have been obtained in the present computational fluid dynamics (CFD) results than in the theoretical results using Rossiter's formula.

• Journal of Advanced Navigation Technology
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• v.21 no.1
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• pp.1-12
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• 2017

As the current ground transportation system becomes saturated, there is a need to develop a roadable personal air vehicle (PAV). Therefore, researches for PAV development and operation system development are being actively carried out in various countries around the world. PAV, the next generation transportation system, is a new concept of personal transportation that combines ground transportation, air traffic, and IT industry. Also, the development of PAV can solve the saturation of traffic congestion and shorten the travel time dramatically. In this study, we analyzed the certification criteria of FAR Part 23, which is going to be revised, and analyzed the patents and folding mechanism of Terrafugia Transition and Aeromobil 3.0, which are the most advanced of roadable PAV. Also, we used $OpenVSP^{(R)}$ for the reverse configuration design of the existing Terafugia transition and Aeromobile 3.0. Aerodynamic analyses were performed for the reverse configuration design using the $XFR5^{(R)}$ program.

• Journal of Korean Society of Transportation
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• v.21 no.5
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• pp.49-58
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• 2003

The Transport policies in Korea have been planned and implemented as a part of a larger economy policy based on the achievement of economic growth. As a result, previous transport policies have been focused mostly on the supply of transport infrastructure. The average annual economic growth of six percent and a twelve percent growth in motor vehicles until the late 90s led to the acceleration of the imbalance between the supply and demand of infrastructure. As such, there is a need to establish an innovative transportation policy in order to increase national competitiveness and provide momentum for national growth in the Twenty one century. This research has developed strategies and policies based on interviews that were carried out with specialists in transport field. Moreover, some transport policies have been established for the year 2020 through the conducting of a survey. The survey was conducted by interviewing respondents on making the priority of transport policies. which was then analyzed using the Data Envelopment Analysis with ranked voting data. The results are as follows. The most urgent matter was considered to be the development of a inter-modal transport system, followed by an integrated service system for public transport, and the need to increase the competitiveness of the transport and logistics industries and to further transport safety. Meanwhile, the provision of transportation for disabled people as well as the elderly was considered to be less important in Korea than in welfare nations. This stems from the belief as further attention needs to be paid to the construction of a public transport system, the establishment of transportation networks construction in preparation for reunification and the North-East Asian era, as well as the privatization of the transport infrastructure.

• International Commerce and Information Review
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• v.16 no.1
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• pp.207-226
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• 2014

A trade logistic informatization system under Open Systems Interconnection(OSI) includes a Port Management Information System, a Maritime Information System, and an Export and Import Batch Processing System. These have made a great contribution in the creation of more convenient and efficient management for the logistics industries in our country. However, this management is exposed to the technological problems of networks due to the explosive use in the sending and receiving of e-documents. For our country to grow as a center for port and logistic information, we should make the best use of the control systems using networks and further advance the export and import logistic systems. Therefore, this study aims to propose management systems for a composite network and an invasion detection system for efficient management of an e-trade network under OSI. Methods to rationalize the internal organizations such as coordination of organizations and human resources according to alloted network functions, commissions and arbitrary decisions, and reorganization of relevant regulations are not discussed here. This study looked at trade network under OSI from the aspect of practical business affairs and presented a basis for further interpretation.

• Journal of Digital Convergence
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• v.18 no.5
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• pp.179-186
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• 2020

The purposes of this paper were: 1) to identify the structural changes of the northeast Asia airport network caused by the pandemic of COVID-19 using social network analysis (SNA) and 2) to suggest proposals for improving airport competitiveness. In this respect, the entire international air routes in northeast Asia airport collected data of 4-10 March 2019 and 9-15 March 2020 through schedules analyzer database of OAG. We found that both the density and centrality have decreased since the spread of COVID-19. The government and airport authorities need active support such as a reduction of various fees and a moratorium on transportation rights to overcome the crisis in the air transport industry. When the COVID-19 situation calms down in the future, we hope that further research will be conducted to identify the structural changes in the SNA aspects through the vast data establishment in countries such as the EU and America.

• Korean Security Journal
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• no.60
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• pp.9-31
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• 2019

Due to the development of technology and popularization of drone, the so-called "dirty drone" that exploits drones for crimes and terrorism has become a social problem, and it is time to seriously consider the "revenge of drones." Indeed, the cases of threats posed by drones are expanding not only to threats to ground facilities, but also to aviation safety threats, more recently to large-scale events, demonstrations and crimes targeting specific personnel, and terrorism. This research clearly defined the concept of anti-drone when it emerged as a new type of social safety threat as it was abused in crime and terrorism, while response to it was not enough yet. Through this process, it was intended to present an effective anti-drones system. We analyzed the major controversial elements of anti-drone, and defined them as "comprehensive response activities at the legal, institutional and technical levels performed by law enforcement agencies, related technology and industrial entities in a way that prevents, detects, and blocks acts that violate public well-being and order, such as crimes and terrorism caused by the drones." To effectively respond to dirty drones, the authority of law enforcement agencies and the enactment of relevant laws were proposed. In the future, a comprehensive and systematic follow-up study of the anti system should be conducted.

• Korean Journal of Remote Sensing
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• v.35 no.6_1
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• pp.987-997
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• 2019

Recently the demand for drones is rapidly increasing, as developing Unmanned Aerial Vehicle (UAV) and growing interest in them. Compared to traditional satellite and aerial imagery, it can be used for various researches (environment, geographic information, ocean observation, and remote sensing) because it can be managed with low operating costs and effective data acquisition. However, there is a disadvantage in that only a small area is acquired compared to the satellite and an aircraft, which is a traditional remote sensing method, depending on the battery capacity of the UAV, and the distance limit between Ground Control System (GCS) and UAV. If remote control at long range is possible, the possibility of using UAV in the field of remote sensing can be increased. Therefore, there is a need for a communication network system capable of controlling regardless of the distance between the UAV and the GCS. The distance between UAV and GCS can be transmitted and received using simple radio devices (RF 2.4 GHz, 915 MHz, 433 MHz), which is limited to around 2 km. If the UAV can be managed simultaneously by improving the operating environment of the UAV using a Long-Term Evolution (LTE) communication network, it can make greater effects by converging with the existing industries. In this study, we performed the maximum straight-line distance 6.1 km, the test area 2.2 ㎢, and the total flight distance 41.75 km based on GCS through LTE communication. In addition, we analyzed the possibility of disconnected communication through the base station of LTE communication.

• The Korean Journal of Applied Statistics
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• v.29 no.1
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• pp.13-25
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• 2016

High-speed railway (Korea Train Express) has had a deep impact on the regional economy of Korea. Current high-speed rail research is mostly theoretical, there is a lack of quantitative research using a precise algorithm to study the effect of high-speed railway on the regional economy. This paper analyses the influence of high-speed rail on the regional economy, with a focus on the Daegu area. Quantitative analysis using department store indexes and regional medical records is performed to calculate the economic influence of high-speed rail. The result shows that high-speed railway effects the regional economy though regional consumption growth and medical care trends.