• Transactions of the Korean Society of Mechanical Engineers A
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• v.27 no.4
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• pp.614-622
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• 2003

In this paper, the stress-strain curves of bearing steels at hot working conditions are obtained by hot compression test with a computer controlled servo-hydraulic Gleeble 3800 testing machine and elongations and reductions of area of the bearing steels are also obtained by hot tensile test with a Gleeble 1500 testing machine. Experiments are conducted under the various strain-rates and temperatures and their results are used to obtain the flow stress information. A rigid thermo-viscoplastic finite element method is applied to the multi-stage hot forging process in order to predict temperature distribution of workpiece. The experimental results and the analysis results are used to obtain an optimal hot forging condition.

• The Journal of Korean Academy of Prosthodontics
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• v.13 no.1
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• pp.23-26
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• 1975

The purpose of this study was to measure the retentive force of various kinds of dental cement. Cross-cutting the half of the occlusal surface, pinholes were prepared on the dentin with No. 557 carbide bur. No. 557 steel burs were cemented in the pinholes and retentive force was measured by removing the burs with Instron testing machine. The Instron testing machine was operated at a rate of 0.2 cm per minute. The following results were obtained : 1. The retentive force of zinc phosphate cement(A), reinforced zinc oxide and eugenol cement and polycarboxylate cement were similar to each other, but that of zinc phosphate cement (A) was the highest of all. 2. The retentive force of zinc phosphate cement (B) was the lowest of all.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.11a
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• pp.838-843
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• 2005

The nonlinear characteristics of a suspension is directly related to the ride quality of a passenger car. In this study, a dynamic experiment for a spring and a damper of a passenger car is performed to analyze the nonlinear characteristics using MTS 1-axial testing machine and a mathematical nonlinear dynamic suspension model based on experimental data is devised to estimate the ride quality using Billings' method. The devised nonlinear model is applied to the ride quality analysis using K factor and the effect of suspension parameters is examined. As a result, the friction between the cylinder and the piston of a damper is the most effective parameter for the ride quality of a passenger car.

• Journal of Engineering Education Research
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• v.21 no.4
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• pp.20-27
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• 2018

In this paper, we conducted an analysis of existing materials of material mechanics, surveying educational demands, and selecting art fields for mechanical engineering in collaboration with experts in the fields of aesthetics and renaissance in order to develop educational materials conversed with humanities and arts. In addition, as a core education tool for convergence education, it was developed with an education kits that can be disassembled, assembled and carried by students. As a results of research, education materials were introduced various arts, linked to the engineering thinking. And measurement experiments of material characteristics were carried in a general classroom using developed education kits. From a paper results, the artistic sensitivity of the students will be enhanced and the students' creative problem solving ability will be improved as the ultimate goal of convergence education.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 1993.10a
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• pp.648-655
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• 1993

The hydraulic coconut dehusking machine consists of three main parts ie. The frame , the power unit including the hydraulic accessories, the lifting and dehusking mechanisms. Two sets of the hydraulic coconut dehusking machine were developed . their hydraulic and electrical control circuits were connected in series to enable them operating contemporaneously. Two operators are required to operate the machine. Each of them put a coconut on the lifting mechanism in order to start the working cycle automatically. As a result, the nut are immediately pushed up and seized by the holding teeth under the supplement of the hydraulic reducing circuit. After that the dehusking mechanism started operating via the sequence circuit. At the end of the cycle, both mechanisms return to their original positions. Some remaining fibrous is taken out manually from the nut subsequently . The continuous dehusking speed was found to be 22.2 seconds per 2 coconuts.

• Journal of Practical Engineering Education
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• v.15 no.2
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• pp.419-427
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• 2023

In this study, optimal adhesion conditions to alleviate defects caused by heat shrinkage with FDM type 3D printers with machine learning are researched. Machine learning is one of the "statistical methods of extracting the law from data" and can be classified as supervised learning, unsupervised learning and reinforcement learning. Among them, a function model for adhesion between the bed and the output is presented using supervised learning specialized for optimization, which can be expected to reduce output defects with FDM type 3D printers by deriving conditions for optimum adhesion between the bed and the output. Machine learning codes prepared using Python generate a function model that predicts the effect of operating variables on adhesion using data obtained through adhesion testing. The adhesion prediction data and verification data have been shown to be very consistent, and the potential of this method is explained by conclusions.

• Journal of Korea Society of Industrial Information Systems
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• v.4 no.4
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• pp.40-46
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• 1999

This paper introduce a Koran-Japanese machine translation system which is a module in the spoken language interpreting system It is implemented based on the TDMT(Transfre Driven Machine Translation). We define a new unit of translation so called TOKEN. The TOKEN-based translation method resolves nonstructural feature in Korean sentences and increases the quaity of translating results. In our system, we get rid of useless effort for traditional parsing by performing semi-parsing. The semi-parser makes the dependency tree which has minimum information needed generating module. We constructed the generation dictionaries by using the corpus obtained from ETRI spoken language database. Our system was tested with 600 utterances which is collected from travel planning domain The success-ratio of our system is 87% on restricted testing environment and 71% on unrestricted testing environment.

• Transactions of the Korean Society of Automotive Engineers
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• v.15 no.1
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• pp.171-176
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• 2007

An important challenging issue in the automotive industry is the light-weight, safe design and enhancement of crash response of an auto-body structures. These objectives lead to increasing adoption of high strength steel sheet for inner and outer auto-body members. This paper evaluates the dynamic tensile characteristics of high strength steel sheets, HS45R, TRIP60, DP60 and DP100, along the rolling direction and transverse direction. Static tensile tests were carried out at the strain rate of 0.003/sec using the static tensile machine (Instron 5583). Dynamic tensile tests were carried out at the range of strain rate from 0.1/sec to 200/sec using a high speed material testing machine developed. The tensile tests acquire stress-strain relation and strain rate sensitivity of each material. The experimental results show two important aspects for high strength steels: the flow stress increases as strain rate increases; the strain hardening decreases as the tensile stress increases. The experiments also produce interesting results that the elongation does not decrease even when the strain rate increases.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.18 no.4
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• pp.62-68
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• 2019

The aim of this study was to interpret the structure and dynamics of a transfer shuttle system as a material supply device for small machine tools. The following conclusions were obtained by performing a structural interpretation of the material supply equipment with respect to workload and the dynamical interpretation of a flexible multibody carriage shuttle. When a 1,000-kg workload was applied to a fork lift, the safety factor was approximately 1.86. To conservatively assess the integrity of the structure, a 1,000-kg workload would be proper. In the case of a deflection of the fork system, the width increased with increasing time. The greatest deflection occurred at 5.5 s, which was the largest increase in the time point of the fork system.

• Advances in Computational Design
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• v.7 no.3
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• pp.253-279
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• 2022

This study investigated and predicted the Marshall stability of glass-fiber asphalt mix, carbon-fiber asphalt mix and glass-carbon-fiber asphalt (hybrid) mix by using machine learning techniques such as Artificial Neural Network (ANN), Support Vector Machine (SVM) and Random Forest(RF), The data was obtained from the experiments and the research articles. Assessment of results indicated that performance of the Artificial Neural Network (ANN) based model outperformed applied models in training and testing datasets with values of indices as; coefficient of correlation (CC) 0.8492 and 0.8234, mean absolute error (MAE) 2.0999 and 2.5408, root mean squared error (RMSE) 2.8541 and 3.3165, relative absolute error (RAE) 48.16% and 54.05%, relative squared error (RRSE) 53.14% and 57.39%, Willmott's index (WI) 0.7490 and 0.7011, Scattering index (SI) 0.4134 and 0.3702 and BIAS 0.3020 and 0.4300 for both training and testing stages respectively. The Taylor diagram also confirms that the ANN-based model outperforms the other models. Results of sensitivity analysis show that Carbon fiber has a major influence in predicting the Marshall stability. However, the carbon fiber (CF) followed by glass-carbon fiber (50GF:50CF) and the optimal combination CF + (50GF:50CF) are found to be most sensitive in predicting the Marshall stability of fibrous asphalt concrete.