• Proceedings of the KSR Conference
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• 2004.06a
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• pp.392-396
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• 2004

The number of parameters and the number of samples are the key point of trans-log cost function which studied recently. Most of models show that the number of parameters is more than the number of samples. Therefore, these studies gave unreliability of the estimation results. First, we surveyed theoretical cases and researches for the formulation of cost function of railroad industry. Second, we will suggest trans-log cost function by analyzing cost data of KNR. And, the cumulative data will be needed for the confidence of estimation results.

• Journal of Welding and Joining
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• v.22 no.2
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• pp.28-32
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• 2004

Fatigue life at seam weldment of thick plate was estimated using the finite element and FEM-FAT(an exclusive fatigue solver). Finite element meshing at toe and root of weldment was based oil Radaj's theory. Also, the results of FE analysis were compared with experimental results in the point of Miner's Rule. The results of FE and FEM-FAT analysis were in accord with experimental results within 60% confidence. This result reveals that above techniques is useful in assessment of seam weldment and to be an alternative method instead of an object experiment.

• Journal of Korean Institute of Industrial Engineers
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• v.22 no.1
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• pp.65-82
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• 1996

This paper proposes a sequential procedure which can be used to determine a truncation point and run length to reduce or remove bias owing to artificial startup conditions in simulations aimed at estimating steady-state behavior. It is based on the idea of Lyapunov exponent in chaos theory. The performance measures considered are relative bias, coverage, estimated relative half-width of the confidence interval, and mean amount of deleted data.

• Proceedings of the KSR Conference
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• 2004.10a
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• pp.1765-1769
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• 2004

The number of parameters and the number of samples are the key point of trans-log cost function which studied recently. Most of models show that the number of parameters is more than the number of samples. Therefore, these studies gave unreliability of the estimation results. First, we surveyed theoretical cases and researches for the formulation of cost function of railroad industry. Second, we will suggest trans-log cost function by analyzing cost data of KNR. And, the cumulative data will be needed for the confidence of estimation results.

• International Journal of Reliability and Applications
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• v.8 no.2
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• pp.199-210
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• 2007

This paper presents estimations of the generalized Rayleigh distribution model based on grouped and censored data. The maximum likelihood method is used to derive point and asymptotic confidence estimates of the unknown parameters. The results obtained in this paper generalize some of those available in the literature. Finally, we test whether the current model fits a set of real data better than other models.

• The Journal of Korean Physical Therapy
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• v.14 no.4
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• pp.398-411
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• 2002

Objectives: The purpose of present study was to investigate the experience and point prevalence rate and factors related with Low Back Pain (LBP) in train egineers. Methods: Questionnaires were completed by 324 train engineers in Daejeon railroad administration from May 2002. The information was used to estimate odds ratio (OR) and 95$\%$ confidence intervals (CI) for factors relation to LBP. A retrospective study design was used. Results: The experience rate for LBP was 67.9$\%$, 54$\%$ in one year interval prevalence, 53.4$\%$ in 6 months interval prevalence, and 47.8$\%$ in a point prevalence rate. Variables significantly associated with LBP experience were age (p=0.0327), train vibration(p=0.0015), labour hour(p=0.0034), and pay(p=0.0534). As subjects got older, the higher experience for LBP was (OR=1.1, 95$\%$ CI 1.0-1.2). LBP experience rate for people who had felt train vibration was a higher than those who did not (OR=2.5, 95$\%$ CI 1.4-4.4, OR=2.3 95$\%$ CI 1.3-4.0 in a point prevalence). The people who worked for long hour was a higher than those who did not (OR=2.8, 95$\%$ CI 1.4-5.6, OR=2.2, 95$\%$ CI 1.1-4.5 in a point prevalence). The people who were not satisfied with pay was a higher than those who were (OR=1.7, 95$\%$ CI 1.0-3.0). Factors related to a point prevalence rate were train vibration(p=0.0027), chair vibration (p=0.0444), and labour hour(p=0.0340). LBP a point prevalence rate for people who had felt the vibration of train chair was a higher than those who did not (OR=1.8 95$\%$ CI 0.7-2.0). Conclusions: Results from present study indicated that a statistically significant factors associated with LBP experience were age, train vibration, labour hour, and pay, Factors related to a point prevalence rate were also train vibration, the vibration of train chair, and labour hour.

• Asia Marketing Journal
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• v.11 no.3
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• pp.31-56
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• 2009

As the competition intensifies and the market matures, marketers are more and more concerned with the relationship marketing. Many of the previous researches have pointed out that not all of the consumers are relationship-oriented. But none of the previous research has systematically investigated this issue. This research investigated the relationship among the three concepts: consumers' intrinsic characteristics, perceived importance of relational benefits, and relationship building intention with the salesperson. In this research the perceived importance of relational benefits is treated as mediating variable in the relationship between consumers' intrinsic characteristics and relationship building intention with the salesperson. The conceptual model in this study can be depicted as follows. From the consumers' perspective relational benefits can be defined as "the additional benefits consumers can receive in addition to core services through the long-term relationship with the service provider." And in this study two kinds of relational benefits are adopted by reviewing the previous research: confidence benefits and social benefits. Relational benefit received from the salesperson is very important to predict consumers' relationship building intention with the salesperson. The more relational benefits consumer wants from the salesperson, the more relationship building intention he/she has. From this point two hypotheses are derived as follows. Hypothesis 1: As the perceived importance of confidence benefit from the salesperson increases, the relationship building intention with the salesperson increases. Hypothesis 2: As the perceived importance of social benefit from the salesperson increases, the relationship building intention with the salesperson increases. In this study four individual characteristics(risk taking tendency, variety-seeking tendency, product knowledge, trust orientation) are hypothesized to influence the perceived importance of confidence benefits from the salesperson. And three individual characteristics(interpersonal orientation, price consciousness, trust orientation) are hypothesized to influence the perceived importance of social benefits from the salesperson. These 7 hypotheses are as follows. Hypothesis 3: As the risk taking tendency increases, the perceived importance of confidence benefits from the salesperson decreases. Hypothesis 4: As the variety-seeking tendency increases, the perceived importance of confidence benefits from the salesperson decreases. Hypothesis 5: As the product knowledge increases, the perceived importance of confidence benefits from the salesperson decreases. Hypothesis 6: As the trust orientation increases, the perceived importance of confidence benefits from the salesperson increases. Hypothesis 7: As the interpersonal orientation increases, the perceived importance of social benefits from the salesperson increases. Hypothesis 8: As the price consciousness increases, the perceived importance of social benefits from the salesperson decreases. Hypothesis 9: As the trust orientation increases, the perceived importance of social benefits from the salesperson increases. The whole model in this study can be depicted as follows: Data were collected from the 396 consumers who actually trade stocks through the salesperson and were analyzed using structural equation model. The analysis results show that consumers' perceived importance of relational benefits(confidence benefit and social benefit) play the roles of mediating variables in the causal relationship between consumers' inherent characteristics and their relationship building intention with the salesperson. As for the individual characteristics, the influences of variety-seeking tendency, trust orientation, and price consciousness are statistically significant. It was found that variety-seeking tendency has a significant negative effect on the perceived importance of confidence benefit, and that trust orientation has a significant positive effect on the perceived importance of both of confidence and social benefit. Finally it was also found that, on the contrary to the influence direction suggested in the hypothesis, price consciousness has a significant positive effect on the perceived importance of social benefit.

• 한국전산유체공학회:학술대회논문집
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• 2000.10a
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• pp.46-53
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• 2000

To improve the performance at all design points, multi-point optimization method is implemented for the nose fairing shape design of space launcher. The response surface method is used to effectively reduce the huge computational loads during the optimization process. The drag is selected as the objective function, and the surface heat transfer characteristics, and the internal volume of the nose fairing ate considered as design constraints. Full Wavier-Stokes equations are selected as governing equations. Two points drag minimization, and two points drag / heat flux optimization were successfully performed and configurations which have good performance for the wide operation range were derived. By considering three design points, the space launcher shape which undergoes the least drag during whole flight mission was designed. For all the design cases, the constructed response surfaces show good confidence level with only 23 design points with the proper stretching of the design space.

• Proceedings of the KSR Conference
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• 2004.10a
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• pp.793-799
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• 2004

In track a third weakness point is joint part, turnout part, curve part. One of them joint part of rail have been known to the most weak point by loosen of joint bar and fish bolt due to impulse and vibration by wheel contact at times. In addition happen to deformation and failure at end of rail, failure and miniature of ballast gravel. Finally impact between wheel and rail become origin cause of a welded rail, noise and vibration. riding condition deterioration, besides track failure. In the present domestic, Thermite and Gas pressure weldings have been used to continuous welded rail(CWR), however stiffness and confidence in quality is lower than Flash butt welding method. FRW have the excellent capacity, however have a shortcoming large scale of machine and power equipment. Therefore we will introduce Mobile Flash Butt Welder can weld in track.

• Journal of the Korean Geophysical Society
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• v.7 no.2
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• pp.121-134
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• 2004

This study has tried to develop the modified DRASTIC Model by supplying the parameters, such as structural lineament density and land-use, into conventional DRASTIC model, and to predict the potential of groundwater contamination using GIS in Hwanam 2 District, Gyeonggi Province, Korea. Since the aquifers in Korea is generally through the joints of rock-mass in hydrogeological environment, lineament density affects to the behavior of groundwater and contaminated plumes directly, and land-use reflect the effect of point or non-point source of contamination indirectly. For the statistical analysis, lattice-layers of each parameter were generated, and then level of confidence was assessed by analyzing each correlation coefficient. Groundwater contamination potential map was achieved as a final result by comparing modified DRASTIC potential and the amount of pollutant load logically. The result suggest the predictability of contamination potential in a specified area in the respects of hydrogeological aspect and water quality.