• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2003.09a
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• pp.99-101
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• 2003

Unsaturated hydraulic conductivity models have been widely used for the numerical modeling of water flow and contaminant transport in soils. In this study, a simple hydraulic conductivity model is developed by using information of particle-size distribution from the lognormal distribution model and its results are compared with those from the Kosugi-Mualem (KM) model. The accuracy of the proposed model is verified for observed data chosen from the international UNSODA database. Results showed that the proposed model produces adequate predictions of hydraulic conductivities. Performance of this model is generally better than the KM function.

• Proceedings of the KSR Conference
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• 2006.11b
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• pp.1418-1422
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• 2006

The project of advanced urban transit system development is developing the advanced vehicle and the core technologies for the cost down by system change, the transport safety and the environmental friendliness and the improvement of passenger service. The product data management system is installed for management of each project. Various data and informations producted from each project are made for database. Therefore, we develop the product data management system.

• The Journal of Engineering Geology
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• v.4 no.2
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• pp.169-186
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• 1994

A GIS technique was developed for aggregate resources management and transport route analysis. In the study, the management of aggregate resources deals with resources evaluation and control of aggregate supply. The computer system was specially designed for this analysis on the basis of relational database model, and it was named ARIS(Aggregate Resources Information System). A Vector database for this study area of Chungcheong - Do was established for analysis of ARIS. In network analysis, there are many essential elements such as road name, speed limit and width, turns and stops etc. Impedance was also measured for the resistance against transportation of aggregate resources. Actually, the impedances are attributes of arcs, turns and stops. Finally, the feasibility of ARIS was tested to use as a decision making tool of aggregate resources management.

• Proceedings of the KSR Conference
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• 2009.05a
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• pp.1769-1778
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• 2009

Due to the industrialization and urbanization, the transport of hazardous materials increases, which rises possibilities in occurring prospective accidents in terms of hazardous material transport as well. This study applied the model developed from the previous research to analyze the scale of damage areas from the accidents related to hazardous material accidents, as well as suggested a method to measure automatically the scale of accident including casualties and environmental damage based on the guideline which suggests the quantities of hazardous materials exposed from an accident and was defined in the study of standardization for hazardous material classification. A buffering analysis technique of Geographic Information System (GIS) was applied for that. To apply the model which evaluates the scale of population and exposure to environment on each link, rail network, zones, rail accident data, rail freight trips, and locations of rivers etc were complied as a database for GIS analysis. In conclusion, a method to measure damage areas by the types of hazardous materials was introduced using a Clip and a Special Join technique for overlay analysis.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.7 no.5
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• pp.26-32
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• 2008

A pedestrian navigation system, an information delivery server, and a program for naturally guiding (such as speech-guiding) the user of a portable terminal at an intersection. An information delivery server comprises a map database containing data such as nodes including paths constituting intersections, links, and costs of the links. The node-link structure is the most important part in pedestrian navigation system. Functional requirements for the road map database vary in different navigation phases. though there are various road network models, their traditional node-link structures, unfortunately, do not solve the problem well. This paper proposes a node-link structure for pedestrian navigation system. The network topological structure in pedestrianl network is presented, which accords with the practical walking habit better than traditional way treating the entire road network.

• Journal of the Korea Society of Computer and Information
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• v.22 no.9
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• pp.99-105
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• 2017

In this paper, we propose to design and implement the database management system for analyzing vehicle accidents through utilizing integration of the public big data. And the paper aims to provide valuable information for recognizing seriousness of the vehicle accidents and various circumstances at the accident time, and to utilize the produced information for the insurance company policies as well as government policies. For analysis of the vehicle accidents the system utilizes the integrated big data of National Indicator System, the Meteorological Office, National Statistical Office, Korea Insurance Development Institute, Road Traffic Authority, Ministry of Land, Infrastructure and Transport as well as the National Police Agency, which differentiates this system from the previous systems. The system consists of data at the accident time including weather conditions, vehicle models, age, sex, insurance amount etc., by which the database system users are able to obtain the integral information about vehicle accidents. The result shows that the vehicle accidents occur more frequently in the clear weather conditions, in the vehicle to vehicle conditions and in crosswalk & crossway. Also, it shows that the accidents in the cloudy weather leads more seriously to injury and death than in the clear weather. As well, the vehicle accident information produced by the system can be utilized to effectively prevent drivers from dangerous accidents.

• Journal of Korea Spatial Information System Society
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• v.7 no.1 s.13
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• pp.39-52
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• 2005

GML (Geography Markup Language) has become the widely adopted standard for transport and storage of geographic information. So, various researches such as modeling, storage, query, and etc have been studied to provide the interoperability of geographic information in web environments. Especially, there are increased needs to store semi-structured data such as GML documents efficiently. Therefore, in this paper, we design and implement a GML repository to store GML documents on the basis of GML schema using spatial database system. GML Schema is converted into directed GML schema graph and the schema mapping technique from directed schema graph to spatial schema is presented. Also, we define the conversion rules on spatial schema to preserve the constraints of GML schema. GML repository using spatial database system is useful to provide the interoperability of geographic information and to store and manage enormous GML documents.

• Journal of Environmental Health Sciences
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• v.46 no.5
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• pp.610-626
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• 2020

Objectives: This study aims to investigate the concept of microplastics and their occurrence, transport, biological effects, and management methods in the ocean. Methods: I reviewed articles on microplastics in the ocean by using the Google Scholar database. Results: Plastic litter has been reported as a ubiquitous pollutant in the ocean due to the extensive consumption of plastics and the mismanagement of plastic wastes. Microplastics are generally defined as synthetic polymer particles <5 mm in size. Microplastics generated from the degradation of plastic litter are currently a serious global concern since they spread easily all over the ocean, transfer to different tissues inside contaminated animals, and even across different trophic levels inside the food web. An additional concern is the ability of microplastics to adsorb organic and inorganic pollutants and subsequently release them into the ocean. Thus, alternatives to reduce microplastics in the ocean are discussed. Conclusions: This paper summarizes the concept of microplastics and their behavior in the ocean and suggests management methods for microplastics in support of a cleaner ocean.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.46 no.1
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• pp.32-40
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• 2018

In this research, a method of deriving statistical weight prediction formula which is used during the conceptual design phase was studied and it was programmed using Microsoft Excel and verified by applying to jet transport aircraft. The database was built while referencing the variables of conventional wing weight estimation formulas and it was used for modeling the jet transport wing weight regression equation. The model was evaluated using the K-fold cross validation method to solve the overfitting problem of the model.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.22 no.2
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• pp.34-39
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• 2014

Airworthiness authorities specify the technical standards of airworthiness that propose minimum requirement of the commercial transport category and apply the rules in the certification process to ensure the safety of the aircraft. The Federal Aviation Administration and other national airworthiness authorities define the fatal accident risk levels for the safety assessment of the aircraft system and establish standard procedures to apply both qualitative and quantitative analysis techniques. However, an accident or incident may occur by the combination of various factors, although the aircraft is designed in accordance with the strict standards and approval by the Airworthiness Authorities. There are some key factors, such as human error, unpredictable complex system failures, degradation of the components reliability, improper maintenance task and intervals. Risk can be reduced by reflecting aircraft operational experience with similar types of aircraft in the process of aircraft development and safety assessment. Result of the root cause analysis for the Airbus A300-600 incident in which the aircraft engine reverser was deployed in the air have been introduced to reflect the design of system and related components. Also, this paper suggests to create a big-database in order to provide a feed-back to the FAR Part 25 transport category design and safety assessment of the operational experience.