• The Journal of the Korean dental association
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• v.56 no.9
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• pp.462-478
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• 2018

The presence of implant-prosthesis misfits can cause various complications. It is very important to detect misfits to prevent such complications. There are various evaluation methods for misfit assessment including clinical methods and laboratory in vitro methods. The clinical misfit evaluation includes radiographic analysis, visual observation, probing, Sheffield test, evaluation with disclosing materials, and screw resistance test. The laboratory in vitro evaluation method includes indirect modelling evaluation and direct metrological visualization. Of the indirect modelling methods, photoelastic stress analysis, finite element analysis, strain gauge analysis, and microbial colonization analysis were reviewed. Of the direct metrological visualization, microscopic analysis, 3-D photogrammetric analysis, coordinate measuring analysis, and radiographic analysis were reviewed. In this review, the characteristics, advantages and disadvantages of each method were evaluated.

• Transactions of the Korean Society of Automotive Engineers
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• v.23 no.3
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• pp.254-262
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• 2015

This paper presents 3D collision deformation modelling methodologies using photogrammetry for reconstruction of vehicle accidents. A vehicle's deformation shape in collision provides important information on how the vehicle collided. So effective measurement(scanning) and construction of a corresponding appropriate model are essential in the analysis of collision deformation shape for obtaining much information related to collision accident. Two measurement methods were used in this study: Indirect-photogrammetry which requires relatively small amount of photos or videos, and direct-photogrammetry which requires large amount of photos directly taken for the purpose of 3D modelling. When the indirect-photogrammetry method, which was mainly used in this study, lacked enough photographic information, already secured 2D numerical deformation data was used as a compensation. This made 3D collision deformation modelling for accident reconstruction analysis possible.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.05a
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• pp.27-33
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• 2001

Linear harmonic analysis is a convenient and generally accurate method to use for the acoustic analysis of intake and exhaust silencers for IC engines. The major uncertainty in this form of modelling is the characterisation of the source, which is inherently nonlinear and time-variant. Experimental methods are generally used to determine the source characteristics, and in particular the indirect method is most suitable for an IC-engine source. With reference to an idealised linear time-variant source, it is found that the characteristics of a time-variant source as determined by the indirect method have no physical relevance. The direct method of experimental measurement appears to have some advantage over the indirect method, although in practice it is difficult to apply to an IC engine source. Again, an idealised linear time-variant source can be used to indicate that the characteristics of a time-variant source as determined by the direct method also have no physical relevance. Strangely, these meaningless measured source properties can nevertheless be used to accurately predict the radiated noise from an IC engine and silencer system.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.05a
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• pp.559-564
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• 2002

Cross-talk cancellation, inverse filter design or deconvolution in a generic term, is a vital process for a virtual sound realization in the stereo sound reproduction system. Most, if not all, of the design algorithms available for the inverse filter are based on a linearized model of the real physical plant. The result of such a plant-based design method, which may be referred to here as the indirect method, is biased due to both modelling and inversion errors. This paper presents a novel direct cross-talk cancellation method that may be free from the inversion error. The direct method can directly models the inverse filter by a suitable rearrangement of the input and output ports of the original plant so that no inversion is required here. Advantages are discussed with various experiments in an anechoic chamber using a PC soundcard. Binaural reproduction tests conducted showed that the conventional indirect method yields about 8 % reproduction performance error on both ear positions, whereas the direct method offers about 3 %.

• International Journal of Computer Science & Network Security
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• v.21 no.7
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• pp.211-220
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• 2021

The aim of the study is to implement a factor analysis of the determinants of pricing in a state-regulated competitive market using economic and mathematical modelling methods and to develop ways to improve the pricing environment of the market under study. The purpose of the work defines the main objectives: (i) to investigate the features of the competitive model of the Ukrainian flour market; (ii) to analyse the current price conjuncture of the flour market and the dynamics of the main determinants of pricing; (iii)to develop ways of improving the price situation on the flour market on the basis of the factor analysis on the results of economic and mathematical modelling. In order to ensure the reliability and validity of the research results, the following methods were applied: the logical-dialectical method of scientific knowledge in the study of the main theoretical aspects of flour market functioning, the method of logical generalisation and synthesis, comparison, factor analysis, correlation and regression analysis, the graphical method, etc. It has been shown that pricing in a state-regulated competitive market has its own characteristics. For example, in the flour market the price of goods cannot be influenced by producers (sellers) by any methods, therefore determinants of pricing by indirect influence have been taken into account. The five-factor power model of wheat flour price has been constructed. It was substantiated that the price of wheat flour in Ukraine is mostly influenced by consumer price index (0.92 %). The received complex model of wheat flour price may be used also for medium-term forecasting and working out the ways of price formation optimization in the flour market.

• Journal of Korean Academy of Nursing
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• v.30 no.1
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• pp.148-159
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• 2000

The purpose of this study was to test the theoretical model designed to explain juvenile delinquency by media violence. Data were collected through questionnaire survey over a period of 3 months. Subjects served for this study consisted of 537 adolescents including 217 delinquent adolescents and 320 student adolescents in Korea, sampled from Korean student population and delinquent adolescent population confined in juvenile correctional institutions, using proportional stratified random sampling method. In this study, exogeneous variable was family dynamic environment and endogeneous variables were character of adolescent including need satisfaction/ frustration, sociability, antisocial personality tendency, complaints of psychosomatic symptoms and depressive trend, juvenile delinquent behavior and media violence themes including the extent of interest in and exposure and modelling impulsiveness and modelling to media violence themes. A total of 18 instruments were used to operationalized concepts in this model. A validation study indicated that internal consistencies for the 18 instruments which the researcher used were reliable. The one month test-retest correlation for these instruments ranged from 0.54 to 0.88. Statistical methods employed were descriptive statistics and covariance structural modelling. In summarized conclusion, it was found that media violence served as the most contributor to juvenile delinquency by direct effect of 0.64(t=10.18). That is, as the adolescents have to be the higher extent of interest in and exposure and modelling impulsiveness and modelling to media violence themes, they will show the more frequency of delinquent behavior. The single most powerful contributor by total effect of 0.73(t=7.90) (direct effect=0.19, indirect effect=0.54) to the development of delinquent behavior identified in this study was a construct defining family dynamic environment. That is, as the adolescents had to be more unstable family dynamic environment, they became more frustrated to their psychological need, and revealed the more maladaptive personality pattern, consequently they behaved the higher misconducts such as juvenile delinquency through media violence.

• Journal of KSNVE
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• v.10 no.2
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• pp.319-324
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• 2000

This paper shows hot to model the submerged elastic structures and adequate analysis tools for modal behavior when using finite element and boundary element method. Four different cases are reviewed depending on the location of the water and air. First case is that structures are filled with air and water is located outside. Second case is opposite to case one. These cases are solved by direct approach using collocation procedure. Third case is that water is located both sides of structures. Last case is that air is located both sides. These cases are solved by indirect approach using variational procedure. As analysis tools harmonic frequency sweep analysis and eigenvalue iteration method are selected to obtain the natural frequencies of vibrating submerged structures depending on the cases. Results are compared with closed form solutions of submerged spherical shell.

• The Journal of Asian Finance, Economics and Business
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• v.7 no.10
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• pp.413-421
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• 2020

This study aims to develop a research framework to investigate the factors affecting organizational commitment among employees who are working in Foreign Direct Investment (FDI) enterprises in Vietnam. The authors designed an online survey distributed to employees in FDI enterprises, collecting the data from 312 employees. All scales in this study are adopted from previous studies; tools employed include Cronbach's Alpha, Exploratory Factor Analysis, and Confirmatory Factor Analysis (CFA) to examine the internal consistency, reliability, dimensionality, and validity of each variable. Then, the structural equation modelling (SEM) was utilized in order to estimate path correlations between variables. Results indicate that the leadership style has the strongest effect on organizational commitment, followed by job satisfaction and working performance. Moreover, working performance and job satisfaction are also influenced by leadership style. However, there is no statistical evidence to show that job satisfaction has an impact on working performance. In addition, bootstrapping method is used to show the indirect effect of variables; results reveal that leadership style, though, does not have indirect effect on working performance via job satisfaction, but it indirectly affects organizational commitment throughout working performance. In other words, the study finds that working performance mediates the link between leadership style and organizational commitment.

• The Journal of Engineering Geology
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• v.4 no.3
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• pp.343-356
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• 1994

When most of the industry and social indirect facilities such as the large structure, power plant or road, rail-road are constructed, the new slope may lead to the slope failure. The failure models for slopes have been developed by using the results of in-situ and laboratory tests to investigate the mechanisms and types of the slope failure. The safety factor of a slope may be obtained based on the proposed model and the slope can be reinforced to meet the design criteria. The slope should be reinforced by using the optimum model that properly reflects the site condition, the method of reinforcement includes the increased safety factor either by decreasing a slope angle or by reinforcing the slope.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2003.05a
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• pp.1032-1037
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• 2003

Although the holes on the shell case are very important fer the acoustic performance, it is difficult to solve the problem because the case includes thin bodies. Hence, in the past, only the method of trial and error, which depends on the engineer's intuition and experience, was available fur the design of holes. Many researchers have tried to solve the thin-body acoustic problems, since the conventional boundary element method (BEM ) using the Helmholtz integral equation fails to yield a reliable solution fer the numerical modelling of radiation anti scattering of sound from thin bodies. In the area of the analysis of thin-body acoustic problem, three approaches are generally used; the multi-domain BEM, the indirect variational BEM, and the normal derivative integral equation And there has been just a f9w study reported on the design optimization for the acoustic radiation problems by using only the conventional BEM. For the thin-body acoustics, however, no further study in the optimization fields has been reported. In this research, the normal derivative integral equation is adopted as an analysis formulation in the thin-body acoustics, and then used fur the optimization. The analytical approaches for the design of holes are proposed by using a topology optimization technique and a genetic algorithm. The proposed approaches are implemented and validated using numerical examples.