• Journal of the Korean Society for Precision Engineering
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• v.27 no.5
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• pp.36-47
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• 2010

The Korean Railroad Research Institute (KRRI) has developed the rubber tired AGT system (Model: K-AGT) between 1999 and 2005. The K-AGT is a light rail transit system does not require a driver and generally operates on an elevated railroad for transporting passengers. Accidents caused by driverless vehicles can severely affect social confidence, safety and economy therefore, it is very important to minimize the occurrences of such faults, and to accurately perform detailed maintenance tasks and thoroughly investigate the cause of any repeated failures. This research develops the web-based Preventive Maintenance (PM) system for the KAGT train system. The framework of the PM system is based on performing a reliability analysis and a failure mode effects analyses (FMEA) procedure on all the sub-systems in the K-AGT system. Out of the devices that have a low reliability, the high failure ranked devices are included high in the list for performing the overall maintenance plans. Through registration of historical failure data, the reliability indexes can be updated. Such a process is repeated continuously and can achieve very accurate predictions for device operational life times and failure rates. Therefore, this research describes the development of the overall PM system consists of a reliability analysis module, a failure mode effect analysis module, and maintenance request module.

• Journal of Welding and Joining
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• v.26 no.2
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• pp.85-91
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• 2008

In general, the quality of a welding process tends to vary with depending on the work environment or external disturbances. Hence, in order to achieve the desirable quality of welding, we should have the optimal welding condition that is not significantly affected by these changes in the environment or external disturbances. In this study, we used a dual response surface method in consideration of both the mean output variables and the standard deviation in order to optimize the V-groove arc welding process. The input variables for GMA welding process with the dual response surface are welding voltage, welding current and welding speed. The output variables are the welding quality function using the shape factor of bead geometry. First, we performed welding experiment on the interested area according to the central composite design. From the results obtained, we derived the regression model on the mean and standard deviation between the input and output variables of the welding process and then obtained the dual response surface. Finally, using the grid search method, we obtained the input variables that minimize the object function which led to the optimal V-groove arc welding process.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.2 no.1
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• pp.23-35
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• 2008

Mobile IP (MIP) is the solution supporting the mobility of Mobile Nodes (MNs), however, it is known to lack the support for NEtwork MObility (NEMO). NEMO manages situations when an entire network, composed of one or more subnets, dynamically changes its point of attachment to the Internet. NEMO Basic Support (NBS) protocol ensures session continuity for all the nodes in a mobile network, however, there exists a serious pinball routing problem. To overcome this weakness, there are many Route Optimization (RO) solutions such as Bi-directional Tunneling (BT) mechanism, Aggregation and Surrogate (A&S) mechanism, Recursive Approach, etc. The A&S RO mechanism is known to outperform the other RO mechanisms, except for the Binding Update (BU) cost. Although Improved Prefix Delegation (IPD) reduces the cost problem of Prefix Delegation (PD), a well-known A&S protocol, the BU cost problem still presents, especially when a large number of Mobile Routers (MRs) and MNs exist in the environment such as train, bus, ship, or aircraft. In this paper, a solution to reduce the cost of delivering the BU messages is proposed using a multicast mechanism instead of unicasting such as the traditional BU of the RO. The performance of the proposed multicast-based BU scheme is examined with an analytical model which shows that the BU cost enhancement is up to 32.9% over IPDbased, hence, it is feasible to predict that the proposed scheme could benefit in other NEMO RO protocols.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.4
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• pp.2911-2916
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• 2015

The elevated railway station, above which a train is passing, is vulnerable to noise and vibration compared to other station types. To better identify the vibration characteristics of the elevated railway station, the transferred vibration from approach bridges should be analyzed. In this paper, through experiments and simulations, the transfer characteristics of the vibration from approach bridges is analyzed. The study structure is Geomgok station and the anaylses are conducted using ABAQUS three dimensional numerical model. To identify the change in the transfer characteristics for various bearing types, the analyses are performed considering mechanical properties of bearing for railway bridges. The measurement is performed using the accelerometers attached to the approach bridges and the station structure along the passing path of trains.

• Journal of Home Health Care Nursing
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• v.7 no.1
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• pp.73-82
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• 2000

Twenty-first century coming of health care in our country is in a situation of much conflict because the relationship between nurses and doctors is seen in terms of a traditional and vertical structure. Accordingly. it is very difficult to find collaboration amongst individuals of these two professions. Now nursing is trying to find independence and autonomy by carrying out independent professional skills. This study on collaboration and the obstacles hindering its pursuit. The strategies of collaboration to give better health care quality are as follows; First, a program for professionals should be developed to enhance professional knowledge and technology and train nursing professionals so that nursing can be acknowledged as a profession with a power to carry out on independent job. Second, collaboration reduces expenses and results in satisfactory performances of duty, high productivity, low incidence of medical accident, and higher satisfaction of the patient. Therefore the leader in the higher position should take positive stance for collaboration and help create a cooperative situation through the development of practical orders for collaboration. opening cooperative wards, and meeting for collaboration. Third, a collaboration model should be introduced into the courses of the nursing and medical school curriculum, which would influence job atmosphere after graduation. Fourth, nurses should have pride in their jobs as professionals and have confidence in their professional skill, knowledge and ability. Nurses should make an effort to share responsibility and have independence and autonomy. Fifth, common people as well as doctors know little about professional practice and the role of nurses, so a publicity campaign is also required.

• Smart Media Journal
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• v.9 no.2
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• pp.86-91
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• 2020

The current trend of the education market is the development of the fourth industrial revolution and the development of ICT, and various technologies are developing into edu-tech technology that is integrated into the education system. In particular, the market for edu-tech systems capable of lifelike immersive learning effects in virtual space is expanding. However, education in Korean medicine is not objective because of the absence of educational simulators and systems to train and evaluate acupuncture. In this paper, we propose an acupuncture controller and a human body model to increase the effectiveness of acupuncture point training as a follow-up study of "Design of Acupuncture Contents and Dummy for Acupuncture Point Training System". Through the proposed acupuncture controller and Dummy, the accuracy of acupuncture points for the acupuncture point data matching and content motion recognition rate is presented. In addition, the results of temperature and humidity and temperature change tests for evaluating the environmental reliability of the controller are presented.

• Journal of the Korean Society for Railway
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• v.13 no.3
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• pp.304-308
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• 2010

This paper presents a methodology for identifying track irregularity using a wavelet transfer function. An equivalent wavelet SISO (single-input single-output) transfer function is defined by the measured track geometry and the acceleration data measured at a bogie of a train. All the measured data with various sampling frequencies were rearranged according to the constant 25cm reference recording distance of the track recording vehicle used in the field. Before applying the wavelet transform, measured data were regressed by eliminating those out of the range. The inverse wavelet transfer function is also formulated to estimate track geometry. The closeness of the estimated track geometry to the actual one is evaluated by the coherence function and also by FRF (frequency response function). A track irregularity index is defined by comparing the variance of the estimation error from the intact condition and that from the current condition. A simulation study has been carried out to examine the proposed algorithm.

• Journal of the Korean Society for Railway
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• v.18 no.3
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• pp.223-231
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• 2015

This paper proposes a new wireless backhaul technology based on MHN(Mobile Hotspot Network) which uses a wide frequency band of millimeter wave to provide wideband Wi-Fi services for subway passengers. Performance analysis of MHN up and down links, based on data: up and down links structure analysis of physical layer and simulation study of the MHN wireless backhaul link model, show that the proposed MHN-based wireless backhaul network can transmit data at a 1.2Gbps data rate and provide Internet service 100 times faster than that of conventional WiBro-based wireless backhaul networks. These results indicate that the proposed MHN technology is appropriate for subway mobile networks.

• Journal of Digital Contents Society
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• v.11 no.1
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• pp.47-55
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• 2010

Cultural Content Industry, a core industry based on knowledge, is becoming an economic model making new benefits by adding human creativity, imagination, sensitivity and style in to information technology. Cultural Contents Industry representing cultures of each countries is facing major changes towards a new competitive industry of each nation. Cultural content of a country is upbringing new contents power developing into a new industry by flattening the barriers within nations. But cooperations face difficulties in launching the industry because of limited information about the current market and lack of understanding in cultural differences. In order to solve this problem, this paper aims to create global network leading to increase of export and creation of new market with cultural contents and train local specialists. In order to search for the ways to maintain Korean contents in other nations and expand exportation. cooperations invite leading cultural contents groups to South Korea, let the groups experience Korea's contents. Cooperations initiated invite training, dispatch training by Korean companies and international students training. The purpose of this paper is to support education system, ETS-CS(Educational Training System for Contents Specialist) and analyse practices applied in the field to develop a better cultural contents industry.

• Journal of the Korean Society for Railway
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• v.12 no.4
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• pp.499-505
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• 2009

This paper evaluated applicability of railroad reference points for determinating geoid heights. For this research, reference points on the Honam express raildroad which contain ellipsoid heights estimated by GPS/Leveling and orthometric heights by leveling were used. Geoid heights were calculated uisng orthometric and ellipsoid heights of 360 railroad reference points, and the RMSE's with respect to different intervals of reference points were analysed which were induced by interpolation methods. The results showed that no significant difference of RMSE's among interpolation. methods. RMSE's of 0-4km interval of reference points were determined within 2cm and 5-8km were within 3cm. Also, this research confirmed that GPS leveling with Geoid model is not auurate enough to be used for railroad surveying as yet.