• Journal of the Korean Society for Aviation and Aeronautics
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• v.18 no.4
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• pp.44-50
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• 2010

Structural vibration is a significant problem in many multi-part or multi-component assemblies. In aircraft industry, structures are composed of various fasteners, such as bolts, snap, hinge, weld or other fastener or connector (collectively "fasteners"). Due to these, prediction and design involving dynamic characteristics is quite complicated. However, the current state of the art does not provide an analytical tool to effectively predict structure's dynamic characteristics, because consideration of structural uncertainties (i.e. material properties, geometric tolerance, dimensional tolerance, environment and so on) is difficult and very small fasteners in the structure cause a huge amount of analysis time to predict dynamic characteristics using the FEM (finite element method). In this study, to resolve the current state of the art, a new approach is proposed using the FEM and probabilistic analysis. Firstly, equivalent elements are developed using simple element (e.g. bar, beam, mass) to replace fasteners' finite element model. Developed equivalent elements enable to explain static behavior and dynamic behavior of the structure. Secondly, probabilistic analysis is applied to evaluate the PDF (probability density function) of dynamic characteristics due to tolerance, material properties and so on. MCS (Monte-Carlo simulation) is employed for this. Proposed methodology offers efficiency of dynamic analysis and reality of the field as well. Simple plates joined by fasteners are taken as an example to illustrate the proposed method.

• International Journal of Human Ecology
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• v.5 no.1
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• pp.35-43
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• 2004

The purposes of this study are to examine effects of household characteristics and risk tolerance attitude on risk tolerance behavior and to investigate the effect of risk tolerance attitude and behavior on financial satisfaction. For this study, data were collected during October of 2001 through a popular Web site for women in South Korea (www.azoomma.com). The participants in this study were 609 housewives, resulting in 607 with usable data. Multiple regression and path analysis were conducted using the SPSS for Windows. Findings suggest that the greater is risk tolerance attitude, the greater is risk tolerance behavior and those who exhibit more risk tolerance behavior tend to be more satisfied with their personal financial situation. It implies that risk tolerance behavior playa positive role in predicting financial satisfaction. The results have implication for family economists and educators in developing educational program and presenting strategic to increases financial well-being, and also for financial counselors and planners in suggesting portfolio advice to their client

• Korean Journal of Computational Design and Engineering
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• v.17 no.6
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• pp.398-408
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• 2012

This paper investigates the tolerance stack-up in a commercial sliding-type mobile phone model developed by a Korean electronics company, with focus on the dimensional quality of the gap between the sliding top and the main body. The tolerance analysis in this study is done using a commercial software package, which runs Monte Carlo simulations to produce the statistical distributions of the gap size at desired locations. Such an analysis revealed that the original design did not yield the desired dimensional quality of the gap. Through a series of systematic analyses and syntheses, an improved design is proposed for the nominal dimensions and tolerances of selected features of the parts. The proposed design was validated, through tolerance analysis simulation, to meet the desired requirement of the gap quality.

• Journal of the Korea Society for Simulation
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• v.25 no.2
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• pp.83-92
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• 2016

Tolerances are defined as the allowable variations in the geometry and positioning of parts in a mechanical assembly for assuring its proper functionality. Tolerance analysis is the activity related to estimating the potential accumulated variation in assemblies. If the estimated variances go out of the specified ranges, it causes the quality problem. Thus, we should adjust the tolerances and this activity is called as tolerance design. In this paper, a case study on the accumulated tolerance analysis and design using Monte Carlo simulation is introduced, which is applied for developing a portable medical device. Using the simulation study, we can improve the assemblability and functionality of the product.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2010.11a
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• pp.633-634
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• 2010

• Journal of Auto-vehicle Safety Association
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• v.6 no.2
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• pp.43-48
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• 2014

The flexible pedestrian legform impactor(Flex-PLI) consisting of a flexible femur and tibia will be tested for pedestrian protection by global technical regulation(GTR) within the next couple of years as a replacement for the existing transport research laboratory(TRL) legform impactor. In this study, a computer aided engineering(CAE) model was used to perform the effect analysis of each injury with regard to the changes in tolerance factors with the baseline results without tolerance. The tolerance factors were the height of impactor from ground reference line, initial velocity of impactor and rotation of impactor.

• Journal of the Korean Society for Precision Engineering
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• v.27 no.12
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• pp.75-83
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• 2010

Every mechanical part for mass production has dimensions with tolerances in engineering drawing. Tolerance is given to guarantee assemble parts together satisfying functional requirements and dimensional constraints. Tolerance is essential factor for standardization of parts or assembly and has huge influence on manufacturing cost. It will be desirable to have tolerances as broad as possible for minimizing manufacturing cost. This paper describes tolerance analysis of u-joint assembly that is a part of automobile steering system. Within the range of tolerances of parts, accumulated effect is estimated by arithmetic calculation, probability theory and Monte carlo simulation. Each result is compared to investigate the method for increasing productivity.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1996.04a
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• pp.813-818
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• 1996

This paper presents a method for tolerance design using the Taguchi Method(TM) and general purpose mechanism analysis program. Also the tolerance design method is with respect to performance improvement of a mechanism. To use the orthogonal array, mathematical model of a mechanism is established and experiments are carried out by the general purpose mechanism analysis program. The contact model is used to consider a clearance effect. This method is applied to the tolerance design of the VTR Deck mechanism. This method can be used in tolerance design of general mechanisms.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.44 no.2
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• pp.176-179
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• 1999

Trinexapac-ethyl[ 4-(cyclopropyl- $\alpha$ -hydroxy-methylene)-3,5-dioxocyclohexane carboxylic acid ethylester] is a growth-retardant for plants by inhibiting a key step in biosynthesis of GA. A treatment of trinexapacethyl generally induces a reduction in vegetative growth and also inhibits heading. In addition, the trinexapacethyl was known to enhance the freeze-tolerance in annual bluegrass, however, the mechanism is not known yet. One possible reason for the enhanced freeze-tolerance may be the antifreeze protein known to be accumulated in intercellular space of the leaf during cold acclimation. In order to see the possible in-duction of the synthesis of antifreeze proteins by trinexacpacethyl, the apoplastic proteins extracted from Kentucky bluegrass treated with trinexapacethyl were analyzed by SDS-PAGE and the presence of the antifreeze protein was observed. In addition, western analysis showed the identity of the protein induced by both a cold acclimation and a trinexapacethyl treatment. It appears that an enhanced freeze-tolerance of the turf grass by trinexapacethyl is due to the synthesis and/or accumulation of the antifreeze protein similar to the enhanced freeze tolerance induced by cold acclimation.

• Journal of Applied Reliability
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• v.17 no.4
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• pp.362-369
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• 2017

Purpose: Recently, the government of China has established new safety regulations for towing devices. The new Chinese regulation has more unfavorable conditions than the conditions of other countries. So the various measures have been reviewed to satisfy this regulation. Methods: The regulation conditions were compared through analysis of strain energy, and a method for improving the accuracy of analysis is suggested. In addition, the test method considering the tolerance is presented through tolerance analysis. This paper also explained importance of confirming the quality of products through a case of poor quality of Chinese products such as poor heat treatment. Result: We could know how strong Chinese regulations are stronger than other national laws and investigated which member receives a lot of strain energy. In order to cope with these Chinese regulations, we suggested improvement of analysis accuracy, test method through tolerance analysis, and heat treatment quality. Conclusion: This paper contributed to general counterplan of the strengthened new Chinese regulations for towing device.