• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2012.10a
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• pp.394-399
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• 2012

In recent years, MEMS sensors show huge attraction in machine condition monitoring, which have advantages in power, size, cost, mobility and flexibility. They can integrate with smart sensors and MEMS sensors are batch product. So the prices are cheap. And the suitability of it for condition monitoring is researched by experimental study. This paper presents a comparative study and performance test of classification of MEMS sensors in target machine fault classification by 3 intelligent classifiers. We attempt to signal validation of MEMS sensor accuracy and reliability and performance comparisons of classifiers are conducted. MEMS accelerometer and MEMS current sensors are employed for experiment test. In addition, a simple feature extraction and cross validation methods were applied to make sure MEMS sensors availabilities. The result of application is good for using fault classification.

• Journal of Korean Society on Water Environment
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• v.31 no.5
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• pp.507-522
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• 2015

In this study, some of the model verification results of STREAM (Spatio-Temporal River-basin Ecohydrology Analysis Model), a newly-developed hybrid watershed model, are presented for the runoff processes of nonpoint source pollution. For verification study of STREAM, the model was applied to a test watershed and a sensitivity analysis was also carried out for selected parameters. STREAM was applied to the Mankyung River Watershed to review the applicability of the model in the course of model calibration and validation against the stream flow discharge, suspended sediment discharge and some water quality items (TOC, TN, TP) measured at the watershed outlet. The model setup, simulation and data I/O modules worked as designed and both of the calibration and validation results showed good agreement between the simulated and the measured data sets: NSE over 0.7 and $R^2$ greater than 0.8. The simulation results also include the spatial distribution of runoff processes and watershed mass balance at the watershed scale. Additionally, the irrigation process of the model was examined in detail at reservoirs and paddy fields.

• Computers and Concrete
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• v.23 no.1
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• pp.11-23
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• 2019

Nowadays, the characterization of Ultra-High Performance Fiber-Reinforced Concrete (UHPFRC) tensile behavior still remains a challenge for researchers. For this purpose, a simplified closed-form non-linear hinge model based on the Third Point Bending Test (ThirdPBT) was developed by the authors. This model has been used as the basis of a simplified inverse analysis methodology to derive the tensile material properties from load-deflection response obtained from ThirdPBT experimental tests. In this paper, a non-linear finite element model (FEM) is presented with the objective of validate the closed-form non-linear hinge model. The state determination of the closed-form model is straightforward, which facilitates further inverse analysis methodologies to derive the tensile properties of UHPFRC. The accuracy of the closed-form non-linear hinge model is validated by a robust non-linear FEM analysis and a set of 15 Third-Point Bending tests with variable depths and a constant slenderness ratio of 4.5. The numerical validation shows excellent results in terms of load-deflection response, bending curvatures and average longitudinal strains when resorting to the discrete crack approach.

• International journal of advanced smart convergence
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• v.11 no.4
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• pp.104-119
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• 2022

Life safety awareness level diagnosis is necessary for customized safety education and continuous safety awareness. As the starting stage of safety education for each life cycle, a scale that has verified the reliability and validity of high school students' life safety awareness has not yet been developed. In this context, the purpose of this study is to develop and validate the life safety awareness scale of high school students and to analyze interindividual differences. Questionnaire data was collected from April to June 2022 from 834 students in the first, second, and third grades of high schools in △△ city in Jeollabuk-do. A final 25-item scale was developed using the preliminary survey, preliminary test, the main test, descriptive statistical analysis, and exploratory and confirmatory factor analysis. This scale consists of four sub-factors: 'safety prevention', 'safety knowledge', 'safety preparation', and 'safety protection'. Good reliability and validity were verified by analysis of content validity and construct validity. The generalizability of the scale was verified by crossover validation between the search group and the crossover group. Based on the interindividual differences analysis, although there was a difference between genders in life safety awareness, there was no difference by grade level and academic achievement. This study is significant in developing the first valid scale that can measure high school students' life safety awareness and providing the necessity and rationale for life safety education by life cycle considering individual gender differences.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.10
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• pp.2583-2588
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• 2009

This study deals with the shock response analysis of HDD subjected to a half-sine shock pulse and its experimental verification. Comparatively, accurate computer simulation allows designers to determine complete mechanical information during the product impact time period, compared with only segmental messages by sensors in a test, to predict potential failures. But, impact/shock simulation technology is rather sensitive to various factors to predict the shock behavior without validation. In our shock simulation, the methodology of analysis with LS-DYNA3D and test validation is adopted to predict the shock behavior of HDD. We can confirm the soundness of the present shock simulation through the comparison with electromagnetic shock test(200G/1ms) and linear drop test(300G/2ms).

• Journal of the Korean Society of Safety
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• v.28 no.1
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• pp.18-23
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• 2013

The purpose of this study were to develop and validate a prototype slipmeter used on-site floor. The developed slipmeter was dreg sled type. It measured static coefficient of friction(SCOF). The developed slipmeter was evaluated with ASTM 2508-11 which use four different standard surfaces(polished granite, glazed porcelain, vinyl composite tile, and ceramic tile). The SCOF was then measured with developed slipmeter under the three different contaminants and seven different floors. The test results of slipmeter were also compared with those of BOT-3000, floor surface roughness, and human perception. The test results revealed that developed slipmeter successfully ranked all four standard surfaces and differentiated among standard surfaces with varying degrees of slipperiness. The developed slipmeter couldn't properly measure slipperiness under the two kind of floors(polished tile, ground steel plate) and one kind of contaminant(glycerol). The test results of developed slipmeter had stronger correlation with those of BOT-3000 and floor roughness under the water and detergent solution than under the glycerol. The test results of developed slipmeter also showed stronger correlation with those of BOT-3000 and surface roughness than those of human perception. The newly developed slipmeter had been found to give consistent results under the test conditions except for two kind of floors(polished tile, ground steel plate) and one kind of contaminant(glycerol).

• Journal of the Korean Society of Industry Convergence
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• v.25 no.1
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• pp.55-60
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• 2022

This study conducted the measurements of air flow rate for blower systems with experiment and numerical. A new airflow rate test method is suggested, with which it is possible to accurate measurements and calculate the air flow rate for blower systems. The blower(axial fan) is an industrial fluid machine device that supplies a large amount of air by driving an impeller with an electric motor, and it is widely used throughout the industry such as steel, power plant, chemical, semiconductor, LC D, food, and cement. The airflow from the blower is for exchanging the heat in the cooling unit or heat exchanger. The temperature of coolants and hydraulic oil primarily depends on the amount of airflow rate through the cooling package so its accurate estimation is very important. Moreover, it required a larger investment in time and cost since it could not be executed until the system is actually made. Therefore, this research is intended to examine the phenomenon of air flow pattern when testing air flow rate, suggested new test method, and show the result of the validation test.

• Proceedings of the KSR Conference
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• 2003.05a
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• pp.462-467
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• 2003

According to the computerization of railway signalling system, necessity of communication protocol for interface between these equipments is increasing. Therefore the research on communication protocol structure that is required according to computerization trend of these signalling goes. In our research the existed protocol currently used was analyzed, and the simulation modeling for performance analysis is deduced. Based on this simulation model the performance analysis and comparison is carried out, and also validation test is executed about new suggested protocol.

• Computers and Concrete
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• v.4 no.1
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• pp.49-66
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• 2007

The objective of this paper is to provide experimental data on the propagation of curved crack-surfaces and the respective load-displacement diagrams for the validation of numerical models for cracking of concrete, subjected to three-dimensional stress states. To this end beam-shaped specimens are subjected to combined bending and torsional loading, leading to the formation of a spatially curved crack-surface. The experimental data contain the evolution of the load and of the strains at selected points in terms of the crack mouth opening displacement and the propagation of the crack surface.

• Journal of the Korea Society of Computer and Information
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• v.13 no.3
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• pp.57-63
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• 2008

As diverse memory cards based on NAND flash memory are getting popularity with consumer electronics such as digital camera, camcorder and MP3 player the compatibility problems between a newly developed memory card and existent host systems have become a main obstacle to time-to-market delivery of product. The common practice for memory card compatibility test is to use a real host system as a test bed. As an improved solution, an FPGA-based prototyping board can be used for emulating host systems. However, the above approaches require a long set-up time and have limitations in representing various host and device systems. In this paper, we propose a co-validation environment for compatibility test between memory card and host system using formal modeling based on Esterel language and co-simulation methodology. Finally, we demonstrate the usefulness of the proposed environment with a case study of real memory card development.