• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.21 no.6
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• pp.878-884
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• 2012

In this paper, we consider the sway suppression control problem for container cranes with the frictions between the trolley and the rail. If the friction effects in the system can be modelled, there is an improved potential to design controllers that can cancel the effects. The proposed control improves the trolley positioning and sway suppressing against various frictions. The proposed synthesis combines a variable structure control and the adaptive control to cope with various frictions including the unknown constants. First, the variable structure control with the simple switching action is designed, which is based on a class of feedback lineariztion methods for the fast stabilization of the under-actuated sway dynamics of container. Second, the adaptive control with a parameter estimation is designed, which is based on Lyapunov stability methods for suppressing the oscillation of the trolley travelling, especially due to Coulomb friction in the vicinity of the target position. The asymptotic stability of the overall closed-loop system is assured irrespective of variations of rope length. Simulation are shown under initial sway, external wind disturbances, and various frictions.

• Land and Housing Review
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• v.11 no.2
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• pp.1-14
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• 2020

The aim of this study is to empirically identify the differentiating characteristics of determinant factors on sing-person households' commuting mode choice compared to multi-person households' one in order to establish the customized police directions to decrease private car use in commuting. While the study use the 2% sample survey data on the population and housing in 2015, it employ multinomial logit models on relative choice probability of such alternative commuting modes as bus, subway or rail, and walking, rather than driving. As potential determinant factors, the study employs demographic, socio-economic, and housing and residential one for both models of single-person and multi-person households. The study finds that the behavior of commuting mode choice has distinctive difference by gender, marriage status, physical activity constraint, job type, residential period in current housing of the single-person household's workers compared to the multi-person households' ones. Based on the findings, the study deduce ten commuting policy directions customized for the single-person household.

• Journal of Institute of Control, Robotics and Systems
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• v.20 no.10
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• pp.1008-1013
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• 2014

This paper introduces an adaptive anti-sway tracking control algorithm for container cranes with unknown payloads and friction between the trolley and the rail. If the friction effects in the system can be modeled, there is an improved potential to design controllers that can cancel these effects. The proposed control improves the sway suppressing and the positioning capabilities of the trolley and hoisting against uncertain payload and friction. The variable structure controls are first designed based on a class of feedback linearization methods for the stabilization of the under-actuated sway dynamics. The adaptation mechanism are then designed with parameter estimation of unknown payload and friction compensation for the trolley and hoisting, based on Lyapunov stability methods for the accurate positioning and fast attenuation of trolley oscillation due to frictions in the vicinity of the target position. The asymptotic stability of the overall closed-loop system is assured irrespective of variations of rope length. Simulations are shown under various frictions and external winds in the case of no priori information of payload mass.

• Journal of the Korean Geotechnical Society
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• v.29 no.11
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• pp.49-60
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• 2013

The plan for major design-build projects of railway link among countries in gulf area (GCC) and freight rail construction is recently announced, but Korean companies have a hard time tendering due to special geotechnical condition in the Middle East. The major geotechnical risks during railway construction in the Middle East are related to ground improvement of soft Sabkha ground, wind-blown sand mitigation measure, dune sand compaction, and construction of large-scale cut and embankment. In this study, the characteristics of special geotechnical condition and potential geotechnical risks during railway construction in the Middle East are discussed on the basis of field observation, literature review, and field and laboratory test results.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2015.10a
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• pp.549-552
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• 2015

The Korean government establishes a strategy to develop the Busan New Port as a world ranking two transit-oriented port. This paper aims at presenting an efficient Inter-Terminal Transportation system in the Busan New Port as a method of achieving the government strategy. It proposes four systems to treat Inter-Terminal Transportation in the port; Double stack Multiple Trailer System (DMTS) Rail-based transportation system, Private road for Inter-Terminal Transportation, and platform for Inter-Terminal Transportation. This is shown to highly potential for efficient Inter-Terminal Transportation in the port.

• KIEAE Journal
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• v.9 no.5
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• pp.77-84
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• 2009

This study was initiated by the fact that Kangwon Land and large sized resorts was failed the financial benefit to the local residents. This research analyzed the best important tourist resource among the main tourist resource by perception interviewing local residents and related professionals. This study shows that the leisure resource was most important resource field in Jeong-Seon. So more attention to the leisure resources and investment them. Among natural attraction resources 'Hwa-Ahm cave and Hwa-Ahm mineral water' is estimated to have most potential for the strategic financial support. In leisure sector 'High One resort' is judged to be more important attraction resource by professionals but a case of local residents 'Dong-gang Rafting' and 'Rail Bike' were estimated more important resources rather than 'High One resort;. Lastly, in cultural resources, although the importance is a bit behind natural attraction and leisure resources, 'Jeong-Seon 5th day market' and 'Araree village' should be the core linking other related cultural resources. In order to activate tour industry and development of Jeong-Seon area, it is necessary to find identify of regional owned attraction resources and to build tourist attraction infra structure by selecting core bases of existing major attraction points and linking other various resources to those core bases.

• Proceedings of the KSR Conference
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• 2005.11a
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• pp.356-361
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• 2005

Earth brush for electrical multiple units(EMUs) is a device through which the current of the EMU load's consumed power fed from the DC 1,500V overhead line (or from the AC 25.000V catenary) flows via axle to the rail(ground) and which prevents the electric corrosion of the axle bearings by preventing the current flow to the axle bearings caused by electric potential from the magnetic field when the bearings rotate together with the earthing function when a thunderbolt falls or a surge comes. The earth brush wear rates among cars, however, shows quite differences when the earth brushes after being separated from the holders are measured with vernier callipers every 6 months of maintenance period. Main causes of the earth brush wear are divided as mechanical, electric arc and electrical one, and the factors can be running speed, current, harmonics, connection state. spring tension, earth brush material, lubricant and so on. but only the earth brushes of the motor(M1) car show the highest wear rate and moreover maintenance difficulty occurs because of the wear rate differences among e earth brushes in one holder. The reason for these preponderant wear comes from the design concept of making preponderant current flow to some particular earth brushes and moreover the heat generated by the harmonics when the inverter starts to operate accelerate the wear. By defining these causes through experiments. I hope that the found results would be helpful for the future EMU design, safety, economy and maintenance.

• The Korean Journal of Air & Space Law and Policy
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• v.35 no.3
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• pp.39-63
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• 2020

This paper reviews the Interpretative Guidelines on EU passenger rights regulations in the context of the developing situation with COVID-19 of EU commission. To enlighten the obscurity and to mitigate the economic impacts of the COVID-19, European Commission has published "Interpretative Guidelines on EU passenger rights regulations in the context of the developing situation with Covid-19" on March 18, 2020. The Guideline essentially aims to create a coherent system of rules to assist the passengers, industry and national authorities overall under the unprecedented circumstances across the European Union. To do so, the Guideline is drafted to cover the rights of passengers travelling by air, rail, ship or bus/coach, maritime and inland waterways, as well as the corresponding obligations for carriers. From an aviation industry focused perspective, by referencing the Regulation (EC) numbered 261/2004, the Guideline specifically applies to cancellation and delay in flights which are seen as the dark spots for the air carriers concerning potential burdens.

• The Journal of Engineering Geology
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• v.23 no.2
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• pp.127-136
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• 2013

We analyzed the patent trends for whole drilling bits to reveal the main R&D directions, focusing on patents applied for and registered in Korea, the USA, Japan, and Europe. The technology was classified into two groups as a primary classification step (reaming systems and fixed systems), and into seven groups as a secondary classification step (sliding, odex, horizontal pivot, vertical pivot, concentric, eccentric, and etc.). A total of 33,614 patents were retrieved and 870 patents were selected for final effective analysis by data deduplication and filtering. A portfolio analysis using the correlation between the number of patents and the applicants for each patents revealed a sliding system as the key technology with greatest growth potential. From an analysis of the barriers to patents being granted, we emphasize the need to avoid similar topics existing patents or patent applications and to develop differential technology.

• Smart Structures and Systems
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• v.21 no.4
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• pp.435-448
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• 2018

This paper reports the development of a theoretically rigorous method for permanent way engineers to assess the condition of railway ballast under a concrete sleeper with the potential to be extended to a smart system for long-term health monitoring of railway ballast. Owing to the uncertainties induced by the problems of modeling error and measurement noise, the Bayesian approach was followed in the development. After the selection of the most plausible model class for describing the damage status of the rail-sleeper-ballast system, Bayesian model updating is adopted to calculate the posterior PDF of the ballast stiffness at various regions under the sleeper. An obvious drop in ballast stiffness at a region under the sleeper is an evidence of ballast damage. In model updating, the model that can minimize the discrepancy between the measured and model-predicted modal parameters can be considered as the most probable model for calculating the posterior PDF under the Bayesian framework. To address the problems of non-uniqueness and local minima in the model updating process, a two-stage hybrid optimization method was developed. The modified evolutionary algorithm was developed in the first stage to identify the important regions in the parameter space and resulting in a set of initial trials for deterministic optimization to locate all most probable models in the second stage. The proposed methodology was numerically and experimentally verified. Using the identified model, a series of comprehensive numerical case studies was carried out to investigate the effects of data quantity and quality on the results of ballast damage detection. Difficulties to be overcome before the proposed method can be extended to a long-term ballast monitoring system are discussed in the conclusion.