• Journal of the Korean Society of Propulsion Engineers
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• v.20 no.5
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• pp.19-30
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• 2016

We presented a hydrodynamic modeling necessary to accurately reproduce shock-induced detonation of pyrotechnic initiator. The methodology for such numerical prediction of shock propagation is quite straight forward if the models are properly implemented and solved in a well-formulated shock physics code. A series of SSGT(Small Scale Gap Test) and detailed hydrodynamic simulation are conducted to quantify the shock sensitivity of an acceptor that contains 97.5% RDX. A TBI(Through Bulkhead Initiator) system, consisting of a train configuration of Donor(HNS+HMX) - Bulkhead(STS) - Acceptor(RDX), were investigated to further validate the interaction between energetic and non-reactive materials for predicting the detonating response for successful operation of such small pyro device.

• Journal of the Korea Convergence Society
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• v.6 no.6
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• pp.75-80
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• 2015

To train convergence experts ICT infrastructure must be learned IoT use capabilities of things. In this paper, targeted to students that are majoring in computer science, and for the design of the curriculum and the educational model that handles education of operation in general for training IoT-related education for five months to experts of convergence training describe the contents. Course is the basic ability of the process, core competence course, is divided into real-life capability process and on-site training course, was constructed in a total of 10 stages of the process details. Curriculum, it was designed to learn sensing technology, network technology, security, and content production technology. This educational model is utilized for job creation human resource training project of 2015 Ministry of Employment and Labor, it demonstrated the utility to contribute in order to achieve a high completion and the employment rate. Applicable to future university education plans to expand the curriculum, including courses that complement the Java.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.14 no.4
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• pp.18-26
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• 2015

This study is a fundamental research to suggest a forecasting model for short-term railway passenger demand focusing on major lines (Gyeungbu, Honam, Jeonla, Janghang, Jungang) of Saemaeul rail and Mugunghwa rail. Also the author tried to verify the potential application of the proposed models. For this study, SARIMA model considering characteristics of seasonal trip is basically used, and daily mean forecasting models are independently constructed depending on weekday/weekend in order to consider characteristics of weekday/weekend trip and a legal holiday trip. Furthermore, intervention events having an impact on using the train such as introduction of new lines or EXPO are reflected in the model to increase reliability of the model. Finally, proposed models are confirmed to have high accuracy and reliability by verifying predictability of models. The proposed models of this research will be expected to utilize for establishing a plan for short-term operation of lines.

• Journal of the Korean Society for Railway
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• v.14 no.3
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• pp.300-311
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• 2011

In this study, the differences of labor-management cooperation and corporation performance resulted from integrated human resource management types is investigated for 12 urban railroad corporations and then the effect of labormanagement cooperation on the corporation performance is also verified. The results show that the labor-management cooperation and the corporation performance of "closed immersion type" and "opened flexibility type" integrated human resource managements are higher than those of "conservative management type" and "poor management type" integrated human resource managements. As a result of the effect of labor-management cooperation on the corporation performance, it is revealed that "individual cooperation" affects all the corporation performances such as train operation stability, customer's satisfaction, management innovation, self-supporting management, and job satisfaction, whereas "collective cooperation" affects only two coporation performances, management innovation and job satisfaction.

• Proceedings of the KSR Conference
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• 2007.11a
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• pp.1303-1308
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• 2007

Recently, precast concrete tracks are replacing ballast track for efficient and economic maintenance of track. Precast concrete railroad tracks are manufactured in factory, and transported to railroad construction site for installation. Therefore, quality of precast concrete track itself should be sufficiently good. On the contrary to the convenient manufacturing of precast concrete track, the installation of a precast concrete track requires careful steps. Typically, a precast concrete track is placed on an approximately 15-cm thick lean concrete layer. A mortar is filled between lean concrete layer and precast concrete track to adjust the sloping angle of a precast concrete track for a safe train operation at a curvy section. Then, the use of filled mortarproduces a void underneath a precast concrete track, which is harmful to structural safety of a precast concrete track undercyclic loading. Therefore, it is essential to make sure that there is no void left beneath a precast concrete track after mortar filling. In the continuous resonance method, the amplitude of frequency response measured using an instrumented hammer and an accelerometer is plotted against a pseudo-depth, which is half of the wave velocity divided by frequency. The frequency response functions are measured at consecutive measurement locations, 6-cm interval between measurement points, and then combined together to generate a 2-D plot of frequency response. The sections with strong reflections or large amplitude of frequency response are suspicious areas with internal voids and unfilled areas. The 2-D frequency response plot was efficient in locating problematic sections just by examining the color shade of a visualized plot in 2-D format. Some of the problematic sections were drilled to make a visual inspection of mortar filling. The visual image of interface between mortar and precast concrete track was verified using the validity of the continuous resonance technique adopted in this research.

• Journal of Korean Society of Rural Planning
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• v.8 no.2 s.16
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• pp.27-41
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• 2002

This research is written for offering an approach to activate the stagnated industry of the tourist farm through analysis of the current operational problems and situation on some existing tourist farm nominated as such by the authority. There will be some considerations from three different categories : local autonomous groups, tourist farm associations and farm owners. On the other hand, it is assumed that this research can also be utilized as a basic material for activating the tourist farms in the suburban area of Taegu City. The operational problems in the suburban area of Taegu City are as follows : lack of a specialized Product development, the farm operation fund, lack of operational or management ability, lack of public information, etc. There are other Problems regarding law, institution and supporting : complexity of the current system involving all kinds of permission, shortage of financial and taxation supporting, lack of training an expert manpower, lack of ability and cooperation of a deskclerk in charge, etc. Here are some suggestions taking into consideration a respective sector of local autonomous group, tourist farm associations and farm owners for activating the tourist farms in the suburban area of Taegu City. First, a mental turnabout toward a tourist farm is needed from local autonomous groups. The law and institutional base should be arranged while the financial and taxation support is materialized. Second, tourist farm associations should amend or reinforce the existing institution to refresh the current recognition toward the tourist farm through many publicity activities. On the other hand, they should develop the overall tourist farm industry into a better service industry of the rural community by keeping an active system of cooperation with other related groups. Finally, It is advised that they should conceive farms and facilities which can symbolize the tourist farm from the stage of the first construction. In addition to a four-season souvenir development, an effective publicity activity and rational investment management. Above all, they should train themselves in terms of a service spirit before they see the prosperity of the tourist farm community.

• Aerospace Engineering and Technology
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• v.12 no.2
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• pp.209-220
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• 2013

The process of designing and building a human-powered aircraft (HPA) and its performance analysis are introduced in this paper. Light Bros, the Chungnam National University HPA team, has developed Volante, a HPA, to compete in the 2012 exhibition of human-powered aircraft hosted by Korea Aerospace Research Institute. The power train system is composed of a two-blade propeller and Bevel-type gear and the ground test bed is built to simulate the operation. A study has been made to find a efficient propeller based upon the test result of thrust and power available from a pilot under various propeller conditions and running time. The load and structural analysis is conducted for the glider-shaped wing made of composite material which has very high aspect ratio. The spar is analyzed using finite element modeling followed by the comparison of its displacement and strain on structural test. As a result, the performance and safety is confirmed.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.35 no.2
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• pp.515-524
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• 2015

The number of occurrence of differential settlement and track irregularity at track transition zone recently comes to increase, which leads to frequent maintenance activities that have an impact on train operation. Such track transition zone damages are attributed to the change of mechanical properties of fill materials due to environmental factors such as rainfall and freeze, and thaw. Consequently, this study attempts to establish the soil water characteristic curve (SWCC) of fill materials, and conduct seepage analysis to assess the distribution of degree of saturation (DOS) for track transition zone in case of rainfall. The SWCC of fill materials was successfully obtained using filter paper test method. The results of seepage analysis revealed that rainfall intensity, the slope of backfill, backfill condition (fill or cut), and SWCC are significantly influential in controlling the distribution of DOS.

• Journal of Digital Convergence
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• v.18 no.10
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• pp.437-442
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• 2020

Information boards installed in Seoul subway stations are currently in four languages: Korean, English, Chinese, and Japanese. Informational announcements are provided to inform the main information or operation information through the LCD monitor installed in the train and in Korean. However, users are confused because the subway guide board screen displays advertisements more heavily than driving information As a research method, we grasped the current status and problems of the subway guide board installed on the Seoul subway, and presented an improved new subway guide board drafts. An online survey was conducted on 67 people, ranging from teens to 60s who mainly use the Seoul Metro. As a result of the study, the screen design is different for each boarding route, so it is necessary to unify the subway guide board that provides only necessary information. In particular, since the user transfers the subway several times in order to move from place to place, the subway guide board design should function as an emergency disaster guide or boarding information, not an advertising signboard.

• 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.