• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2004.11a
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• pp.175-181
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• 2004

A construction project of Incheon 2nd bridge, which is connected between the Incheon Song-Do New Town and the Incheon International Airport in Young-Jong-Do, have been proposed by the private capital in 1999. But the optimal span width in the bridge main span have not been decided in spite of the three investigations into the feasibility of ship's safe transit in this planned bridge. In this paper, we study the optimal main span width according to the traffic volume in the future traffic and the ship maneuverability of maximum size aspect. The result cf this study, Incheon 2nd bridge main span design is required to design two-way traffic scheme and 1,000m span width, which will satisfy the safe transit from the viewpoint of the traffic volume in the future traffic and the ship maneuverability maximum size.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.09c
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• pp.72-77
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• 2010

The Incheon Bridge, which was opened to the traffic in October 2009, is an 18.4 km long sea-crossing bridge connecting the Incheon International Airport with the expressway networks around the Seoul metropolitan area by way of Songdo District of Incheon City. This bridge is an integration of several special featured bridges and the major part of the bridge consists of cable-stayed spans. This marine cable-stayed bridge has a main span of 800 m wide to cross the vessel navigation channel in and out of the Incheon Port. In waterways where ship collision is anticipated, bridges shall be designed to resist ship impact forces, and/or, adequately protected by ship impact protection (SIP) systems. For the Incheon Bridge, large diameter circular dolphins as SIP were made at 44 locations of the both side of the main span around the piers of the cable-stayed bridge span. This world's largest dolphin-type SIP system protects the bridge against the collision with 100,000 DWT tanker navigating the channel with speed of 10 knots. Diameter of the dolphin is up to 25 m. Vessel collision risk was assessed by probability based analysis with AASHTO Method-II. The annual frequency of bridge collapse through the risk analysis for 71,370 cases of the impact scenario was less than $0.5{\times}10^{-4}$ and satisfies design requirements. The dolphin is the circular sheet pile structure filled with crushed rock and closed at the top with a robust concrete cap. The structural design was performed with numerical analyses of which constitutional model was verified by the physical model experiment using the geo-centrifugal testing equipment. 3D non-linear finite element models were used to analyze the structural response and energy-dissipating capability of dolphins which were deeply embedded in the seabed. The dolphin structure secures external stability and internal stability for ordinary loads such as wave and current pressure. Considering failure mechanism, stability assessment was performed for the strength limit state and service limit state of the dolphins. The friction angle of the crushed stone as a filling material was reduced to $38^{\circ}$ considering the possibility of contracting behavior as the impact.

• Journal of Distribution Science
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• v.12 no.10
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• pp.123-128
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• 2014

Purpose - The purpose of the study is to reexamine the price fairness as practiced by low cost airlines, as a consumer has to experience such inconveniences as inferior airport transportation, extra fees on in-flight meals, and non-negotiable seats, and consumers evaluate such experiences keeping in mind their total costs. This evaluation includes price fairness and allows a reasonable and overall consideration of factors of low cost airlines. It tries to set up a measurement of the indicators consumers' perceptions of price fairness academically as it adapts price fairness to airline services which are renowned for price volatility. Research design, data, and methodology - The research proposes an alternative pricing strategy for the long term profit of low cost airlines after going over conflicts between the traditional theory of consumers' price perception mechanism and flexible fair policy of low cost airlines. It was meaningful when it relates to the early stage of the business, while it enhances the risks relating to the long term survival of low cost airlines. In addition, it is significant as it highlights the negative influences on consumers' perceptions of price fairness, as low cost airlines run on extremely low cost perspectives. Results - The results of the research provide insight into four perspectives, as consumers' perceptions of price fairness are influenced by the frequency and range of price changes and services. The first perspective is that it would lead to positive price evaluation when a low cost airline cuts prices frequently with little changes than one big change. It also would lead to the same result when it comes to necessary services. The second perspective is that one big increase of price would rather undermine the negative aspects of price changes than those of several smaller ones. The third perspective is that additional services would be good to consumers' perceptions of price fairness as compared to discount benefits with respect to the cost. Finally, a low cost airline should consider that consumers will change airlines or defer their flight schedule if the flight fares increase beyond their limits. Conclusions - Low cost airlines should reconsider their pricing policies for services that were provided free earlier. A consumer would not like discount benefits when made to pay for services that were, for long, free of charge. If a low cost airline can provide services with no charge, it should improve volumes if the costs are standardized and, moreover, should consider the charging fees. Alternatively, a consumer can choose between services and fair discount. Low cost airlines are implementing sales promotion strategies, as the competition is more intense than it used to be. In these days, they should regard services over sales promotion, as consumers may prefer to spend money on good premium services. Some differentiation in services could create a good market position for the airlines and, hence, good financial performance.

• Journal of Distribution Science
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• v.15 no.5
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• pp.65-73
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• 2017

Purpose - The Service Level Agreement which has been used in the IT information communication industry to maintain the level of service supplied by a vendor has been adopted in the service industry surrounding the airliners and airports. Considering that service quality is dependent on attitude of employees who are responsible to provide service, it is very important to understand what kinds of effects SLA(service level agreement) has on the attitude when SLA is applied to the service industry. SLA is an agreement between management authority and service providing contractor to make sure that certain level of service quality should be provided. For employees whose responsibilities are providing the service, SLA has both positive effects and negative effects. Negative side is that employees have to follow many irrigating complicated rules. On the other hand, the attribute of rules is that once one is become accustomed to them one may feel comfortable doing repeated same kinds of works, which is positive side for the workers. Research design, data, and methodology - We analyzed whether the SLA has moderating effects while service providers' job environment of outsourcing companies affects job satisfaction. Especially in the service industry, job satisfaction has great effects on productivity and efficiency. Results - The study results show the following. First, SLA has moderating effects while task performance environment affects treatment satisfaction. Second, SLA has moderating effects while task motivation environment affects treatment satisfaction. Third, SLA has moderating effects while physical work environment satisfaction affects treatment satisfaction. Fourth, on the other hand, the difficulties caused by SLA have moderating effects while the relationship among employees affects job dissatisfaction, which is negative side of SLA. From these results, we can tell that SLA has more positive moderating effects on treatment satisfaction on the whole. which results can be used to justify applying SLA to the service industry. Conclusions - In this study we analyzed the effects of SLA which have become more important in service industry nowadays on service providing employees. For managing side, the positive effects of SLA have to be emphasized while the negative effects should be avoided or minimized.

• Journal of Navigation and Port Research
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• v.28 no.10 s.96
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• pp.933-940
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• 2004

A construction project of Incheon 2nd bridge, which is connected between the Incheon Song-Do New Town and the Incheon International Airport in Young-Jong-Do, has been proposed by the private capital in 1999. But the optimal width of the main span has not been decided in spite of the three investigations into the feasibility of ship's safe transit in this planned bridge. In this paper, we study the optimal width of the main span according to the traffic volume in the future traffic and the ship maneuverability of maximum size aspect. The result of this study, the channel in the main span of Incheon 2nd bridge is required to design two-way traffic scheme and the width of 1,000m, which will satisfy the safe transit from the viewpoint of the traffic volume in the future traffic and the ship maneuverability of maximum size.

• International Journal of Highway Engineering
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• v.11 no.1
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• pp.165-175
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• 2009

With the current move towards adopting mechanistic-empirical concepts in the design of pavement structures, state-of-the-art mechanistic analysis methodologies are needed to determine accurate pavement responses, such as stress, strain, and deformation. Previous laboratory studies of pavement foundation geomaterials, i.e., unbound granular materials used in base/subbase layers and fine-grained soils of a prepared subgrade, have shown that the resilient responses followed by nonlinear, stress-dependent behavior under repeated wheel loading. This nonlinear behavior is commonly characterized by stress-dependent resilient modulus material models that need to be incorporated into finite element (FE) based mechanistic pavement analysis methods to predict more realistically predict pavement responses for a mechanistic pavement analysis. Developed user material subroutine using aforementioned resilient model with nonlinear solution technique and convergence scheme with proven performance were successfully employed in general-purpose FE program, ABAQUS. This numerical analysis was investigated in predicted critical responses and domain selection with specific mesh generation was implemented to evaluate better prediction of pavement responses. Results obtained from both axisymmetric and three-dimensional (3D) nonlinear FE analyses were compared and remarkable findings were described for nonlinear FE analysis. The UMAT subroutine performance was also validated with the instrumented full scale pavement test section study results from the Federal Aviation Administration's National Airport Pavement Test Facility (FAA's NAPTF).

• Journal of Korean Tunnelling and Underground Space Association
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• v.23 no.5
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• pp.325-337
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• 2021

On the road and rail tunnels, the evacuation pathway and facilities such as smoke-control and fire suppression system are essential in tunnel fire. In the long twin tunnels, the cross-connection tunnel is usually designed to evacuate from the tunnel where the fire broke out to the other tunnel. In twin shield tunnels, the segment lining has to be demolished to construct the cross-connection tunnel. Considering the modern shield TBM is mostly the closed chamber type, the exposure of underground soil induced by removal of steel segment lining is the most danger construction step in the shield tunnel construction. This case study introduces the excavation method using the thrust of large steel pipe and reviews the measured data after the construction. The large steel pipe thrust method for the cross-connection tunnel can stabilize the excavated face with the two mechanisms. Firstly, the soil in front of excavated face is cylindrically pre-supported by the large steel pipe. Secondly, the excavated face is supported by the plugging effect caused by the soil pressed into the steel pipe. It was reviewed that the large steel pipe thrust method in the cross-connection tunnel is enough to secure the construct ability and stability in soil from the measurement results about the deformation and stress of steel pipe.

• Journal of Korea Trade
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• v.25 no.8
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• pp.57-74
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• 2021

Purpose - This study aims to analyze the characteristics of network construction by Norwegian Air and AirAsia X, which are recognized as leading airlines in the long-haul LCC market. Based on this analysis, this study intends to provide implications for networking strategies for Korean LCCs that seek to enter the long-haul market when the aviation market stabilizes again upon the end of the COVID-19 pandemic. Design/methodology - To conduct the network analysis on long-haul low-cost airlines, the Official Airline Guide (OAG) Schedule Analyzer was used to extract long-haul data of Norwegian Air and AirAsia X. To analyze the trend of the long-haul route network, we obtained the data from 3 separate years between 2011 and 2019. The network was analyzed using UCINET 6.0 in order to examine the network structure of long-haul low-cost airlines and the growth trend of each stage. Findings - Analyzing the network of long-haul routes by visualizing the network structure of low-cost carriers showed the following results. In its early years, Norwegian Air's long-haul route network, centering on regional airports in Spain and Sweden, connected European regions, the Middle East, and Africa. As time passed, however, the network expanded and became steadily strong as the airline connected airports in other European countries to North America and Asia. In addition, in 2011, AirAsia X showed links to parts of Europe, such as London and Paris, the Middle East and India, and Australia and Northeast Asia, centering on the Kuala Lumpur Airport. Although the routes in Europe were suspended, the network continued to expand while concentrating on routes of less than approximately 7,000 km. It was found that instead of giving up on ultra-long-haul routes such as Europe, the network was further expanded in Northeast Asia, such as the routes in Korea and Japan centering on China. Originality/value - Until the COVID-19 pandemic broke out, Norwegian Air actively expanded long-haul routes, resulting in the number of long-haul routes quintupling since 2011. The unfortunate circumstance, wherein the world aviation market was rendered stagnant due to the outbreak of COVID-19, hit Norwegian Air harder than any other low-cost carriers. However, in the case of AirAsia X, it was found that it did not suffer as much damage as Norwegian Air because it initially withdrew from unprofitable routes over 7,000 km and grew by gradually increasing profitable destinations over shorter distances. When the COVID-19 pandemic ends and the aviation market stabilizes, low-cost carriers around the world, including Korea, that enter the long-haul route market will need to employ strategies to analyze the marketability of potential routes and to launch the routes that yield the highest profits without being bound by distance. For stable growth, it is necessary to take a conservative stance; first, by reviewing the business feasibility of the operating a small number of highly profitable routes, and second, by gradually expanding these routes.

• The Journal of Information Systems
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• v.31 no.3
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• pp.177-195
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• 2022

Purpose This paper aims to prepare a full operational readiness by establishing an optimal flight plan considering the weather conditions in order to effectively perform the mission and operation of military aircraft. This paper suggests a flight prediction model and rules by analyzing the correlation between flight implementation and cancellation according to weather conditions by using big data collected from historical flight information of military aircraft supplied by Korean manufacturers and meteorological information from the Korea Meteorological Administration. In addition, by deriving flight rules according to weather information, it was possible to discover an efficient flight schedule establishment method in consideration of weather information. Design/methodology/approach This study is an analytic study using data mining techniques based on flight historical data of 44,558 flights of military aircraft accumulated by the Republic of Korea Air Force for a total of 36 months from January 2013 to December 2015 and meteorological information provided by the Korea Meteorological Administration. Four steps were taken to develop optimal flight prediction models and to derive rules for flight implementation and cancellation. First, a total of 10 independent variables and one dependent variable were used to develop the optimal model for flight implementation according to weather condition. Second, optimal flight prediction models were derived using algorithms such as logistics regression, Adaboost, KNN, Random forest and LightGBM, which are data mining techniques. Third, we collected the opinions of military aircraft pilots who have more than 25 years experience and evaluated importance level about independent variables using Python heatmap to develop flight implementation and cancellation rules according to weather conditions. Finally, the decision tree model was constructed, and the flight rules were derived to see how the weather conditions at each airport affect the implementation and cancellation of the flight. Findings Based on historical flight information of military aircraft and weather information of flight zone. We developed flight prediction model using data mining techniques. As a result of optimal flight prediction model development for each airbase, it was confirmed that the LightGBM algorithm had the best prediction rate in terms of recall rate. Each flight rules were checked according to the weather condition, and it was confirmed that precipitation, humidity, and the total cloud had a significant effect on flight cancellation. Whereas, the effect of visibility was found to be relatively insignificant. When a flight schedule was established, the rules will provide some insight to decide flight training more systematically and effectively.