• Journal of the Korean Society for Railway
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• v.9 no.6 s.37
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• pp.746-752
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• 2006

The major objective of this study is to investigate the dynamic behavior evaluation of split PC sleepers for railway turnout by the field test. In railway engineering, a turnout is necessary to allow a vehicle to move from one track to another. So, turnout is required very complex railway technologies such as lolling stock, track. In reference to conventional line speed-up and improvement railway, accurate assembly of turnout affects travel ins qualify of turnout area and running safety. Because of heavy weight and a large volume of the long sleeper used to turnout and car limit, transport and the prerequisite for trouble-free transport of the factory pre-assembled major turnout components is achieved through division of long sleepers. The one of the advantages for using a split sleeper is to reduce the dynamic vibration according to the information of developed nations. Therefore, we investigate the characteristic of dynamic behaviors of split sleepers which are adopted for the first time to improve performance of turnout From the field test results of the split sleeper, it is evaluated that the modification of weight, material and stiffness compared with wood sleeper is very effective for the ballast safety. However, the decrease in vibration of split sleeper was not found out.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2018.10a
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• pp.278-281
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• 2018

The early Web technology was to show text information through a browser. However, as web technology advances, it is possible to show large amounts of multimedia data through browsers. Web technologies are being applied in a variety of fields such as sensor network, hardware control, and data collection and analysis for big data and AI services. As a result, the standard has been prepared for the Internet of Things, which typically controls a sensor via HTTP communication and provides information to users, by installing a web browser on the interface of the Internet of Things. In addition, the recent development of web-assembly enabled 3D objects, virtual/enhancing real-world content that could not be run in web browsers through a native language of C-class. Factors that evaluate the performance of existing Web applications include performance, network resources, and security. However, since there are many areas in which web applications are applied, it is time to revisit and review these factors. In this thesis, we will conduct an analysis of the factors that assess the performance of a web application. We intend to establish an indicator of the development of web-based applications by reviewing the analysis of each element, its main points, and its needs to be supplemented.

• Journal of Aerospace System Engineering
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• v.14 no.1
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• pp.21-27
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• 2020

Aircraft should be equipped with various external stores for mission performance. Since these external stores may cause structural instability of aircraft, an evaluation of the effects between the aircraft and the external stores is required. For this purpose, an aircraft dynamic characteristics analysis reflecting an external store was performed, and the finite element model for the analysis of aircraft dynamic characteristics should simulate the dynamic characteristics of the component as accurately as possible while using a minimum of the nodes and elements. In this study, a stick model was constructed for dynamic characteristics analysis of the external fuel tank and installation pylon using MSC Patran/Nastran. For the calculation of the equivalent stiffness of the stick model, a simple beam theory was applied to construct the stick model of each part, and the validity of each stick models was confirmed by mode comparison with the fine model. Additionally, the model analysis of the stick model assembly, simulating a pylon equipped with an external fuel tank was performed to confirm that the basic modes required for the analysis of aircraft dynamic characteristics are well extracted. Finally, it was confirmed that the developed stick model assembly could be used for analysis of aircraft dynamic characteristics by comparing the errors in modes between the fine model assembly and the stick model assembly.

• 한국신재생에너지학회:학술대회논문집
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• 2010.06a
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• pp.125.1-125.1
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• 2010

A high efficiency polymer electrolyte membrane (PEM) fuel cell stack was developed for pressurized pure hydrogen and oxygen supplying conditions. The design objective for the cell stack was to maximize the electric efficiency and to minimize exhaust-gas emissions from it simultaneously. To achieve this objective, the cell stack was designed to use pure hydrogen and oxygen as fuel and oxidant, respectively, and to be operated under high gas inlet pressures and in a stage-wise dead-end operation mode. Major components constituting the cell stack, such as membrane electrode assembly, bipolar-plate, and gasket, have been developed to meet a target durability even in severe operating conditions: high gas inlet pressures and usage of pure oxygen. A high-power fuel cell stack was assembled using these components to verify the performance. The cell stack showed a good performance in terms of the efficiency and maximum power output.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.17 no.9
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• pp.853-861
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• 2007

Currently, automotive industries improve the vehicle performance and reduce the development period of vehicle using each module part for the high quality and performance of vehicles. However each component part doesn't generate the noise and vibration problems, sometime these problems are generated on the assembly status between vehicle chassis frame and each module part. On this study, in order to analysis the dynamic characteristics of a shield door module that is a typical module part of vehicles, the acquisition and evaluation process about the vibration and noise of shield door module is developed. Also the possibility to apply to shield door module of the developed process is verified by the comparison with the dynamic characteristics between plastic and steel module plate.

• Journal of the Korean Society for Precision Engineering
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• v.23 no.5 s.182
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• pp.155-161
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• 2006

This paper introduces a new type of mechanical tape feeder for chip mounter. The mechanical feeder is composed of a pneumatic linear actuator and a linear feeding module with the application of a cam-slider. As semiconductor chips are getting smaller, PCB assembly makers require the feeder to position the chip with high accuracy. The linear feeding system improves the positioning accuracy of the chip by getting rid of the index error, which brings into existence on the sprocket rotating feeder. It also can make greatly reduce the dumping rate. The dumping error is caused by the impact occurred as the pawl to interrupt ratchet wheel rotation. The paper discusses its mechanism and mechanical performance. The positioning accuracy and the dynamic characteristic were measured for long time operation and analyzed. As a result, the feeder showed very good performance. However, the feeding system was dynamically unstable due to the cover film eliminator that is required to be modified

• The Journal of Korea Robotics Society
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• v.13 no.1
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• pp.72-78
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• 2018

This paper proposes a Dual Controller System for Precision Control (DCSPC) for control of the gripper. The DCSPC consists of two subsystems, CDSP (Controller based DSP) and CARM (Controller based ARM processor). The CDSP is developed on a DSP processor and controls the gripping motor and LVDT. In particular, the CARM is implemented using Linux and ARM processor according to recent research related to open-source. The robot for high-precision assembly is divided into the robot control and the gripper control section and controls CARM and CDSP systems respectively. In this paper, we also proposed and measured the performance of communication API. As a result, it is expected to recognize improvements in communication between CARM and the robot controller, and will continue to conduct relevant research among other commercial robot controllers.

• Journal of Hydrogen and New Energy
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• v.11 no.1
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• pp.19-27
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• 2000

The polymer electrolyte membrane fuel cell (PEMFC) system was developed. In order to enhance the performance of membrane electrode assembly (MEA), the transfer printing method of the electrocatalyst layer on membrane was developed. The $H_2/O_2$ single cell with an electrode area of $50cm^2$ was fabricated and tested using 20 wt.% Pt/C as an electrocatalyst and the commercial and hand-made MEA such as Nafion 115, Hanwha, Dow, Flemion T and Gore Select. The 100-cell PEMFC stack with an active electrode area of $300cm^2$ was designed and fabricated using 40 wt.% Pt/C and 30 wt.% Pt-Ru/C as a cathode and anode electrocatalysts, respectively. The performance of PEMFC system was obtained to be 7kW (250A at 28V) and 3.5kW (70A at 50V) at $80^{\circ}C$ by flowing $H_2/air$ and methanol reformed fuel gas/air, respectively.

• Journal of the Korean Institute of Gas
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• v.11 no.4
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• pp.12-16
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• 2007

The fuel pressure regulator mounted on CNG vehicles is used to maintain a constant pressure in the fuel injection system. It needs precise fuel pressure control to obtain benefits of high efficiency and low emissions in CNG vehicles. In this study, a high pressure test rig for the performance evaluation of CNG regulators was introduced. Two different CNG regulators were tested and compared each other at various test conditions. Results showed that dynamic response and creep characteristics are directly effected by the valve assembly design. Gas temperature was dramatically dropped at hish supply pressure conditions, so that effective design for coolant bowl is needed to prevent icing problem.

• Journal of Home Health Care Nursing
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• v.21 no.1
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• pp.14-25
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• 2014

Purpose: The purpose of this study was to analyze key performance indicators using a balanced scorecard in the nursing department of hospitals, and to find useful suggestions for future research. Methods: Before starting the literature search clear inclusion and exclusion criteria were determined. After that, were viewed 41 studies from the RISS, KISS, National assembly library, and NDSLDB. Data were collected on October 17, 2013. Researchers developed an analytic framework for the literature review using a balanced score card development process and construction steps of previous studies. This framework had 10 steps related to the balanced score card development process. Results: A total of 10 studies met the inclusion and exclusion criteria. We identified 234 key performance indicators for the nursing department. The average number was 6.6 in finance perspective, 8.6 in perspective, 11.9 in internal process perspective, and 6.2 in learning and growth perspective. We found that 173 indicators had been cited only once. 61 indicators were cited over twice. Further, 8 indicators employed different perspectives on different studies. Conclusion: The results of the present study summarize useful information on recent trends on key performance indicators using a balanced score card in the nursing department of hospitals. These results will help develop key performance indicators and provide directions for future research.