• Water Engineering Research
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• v.1 no.1
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• pp.11-23
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• 2000

Regional flood frequency analysis has been developed by employing the nearby site's information to improve a precision in estimating flood quantiles at the site of interest. In this paper, single site and regional flood frequency analyses were compared based of the 2-parameter Weibull model. For regional analysis, two approaches were employed. The First one is to use the asymptotic variances of the quantile estimators derived based of the assumption that all sites including the site of interest are independent each other. This approach may give the maximum regional gain due to the spatial independence assumption among sites. The second one in Hosking's regional L-moment algorithm. These methods were applied to annual flood data. As the results, both methods generally showed the regional gain at the site of interest depending on grouping the sites as homogeneous. And asymptotic formula generally shows smaller variance than those from Hosking's algorithm. If the shape parameter of the site of interest from single site analysis is quite different from that from regional analysis then Hosking's results might be better than the asymptotic ones because the formula was derived based on the assumption that all sites have the same regional shape parameter. Furthermore, in such a case, regional analysis might be worse than single site analysis in the sense of precision of flood quantile estimation. Even though the selected sites may satisfy Hosking's criteria, regional analysis may not give a regional gain for specific and nonexceedance probabilities.

• Structural Engineering and Mechanics
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• v.32 no.6
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• pp.725-740
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• 2009

A new simple relation for the estimation of modal correlation coefficients is presented. It is obtained from the decomposition of covariances of modal responses into background and resonant contributions, as it is commonly done for the variances. Thanks to appropriate assumptions, the modal correlation coefficients are estimated as weighted sums of two limit values, corresponding to the background and resonant responses respectively. The weighting coefficients are expressed as functions of the background-to-resonant ratios, which makes the proposed formulation convenient and easily accessible. The simplicity of the mathematical formulation facilitates the physical interpretation. It is for example proved that modal correlation coefficients can be non negligable even in case of well separated natural frequencies, which is sometimes unclear in the litterature. The new relation is mainly efficient in case of large finite element models. It is applied and validated on a finite element buffeting analysis of the Viaduct of Millau, the highest bridge deck ever built so far.

• International Journal of Industrial Entomology and Biomaterials
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• v.10 no.2
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• pp.153-157
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• 2005

Recently two breeding programs were carried out for isolation of new parental inbred lines in Iran. This study was undertaken in order to estimate the combining ability effects and heterosis of these lines. For this purpose an $8\times8$ diallel cross analysis including eight inbred lines of silkworm with four lines from each program were studied for their five quantitative traits. The results indicated that reciprocal effects appeared insignificant for most of traits. Japanese lines of 111 and 113 were best combiners for shell weight, cocoon weight and shell percentage traits. With respect to pupation rate, Chinese line 110 was the best and according to general combining ability (GCA) and specific combining ability (SCA) variances, it is superior in specific combinations. Hybrid $109\times110$ showed better characters for both productive and viability traits. Hybrids with high heterosis had high SCA too.

• Journal of Mechanical Science and Technology
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• v.19 no.spc1
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• pp.350-356
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• 2005

A method of dynamic analysis of mechanical systems considering probabilistic properties is proposed in this paper. Probabilistic properties that result from manufacturing tolerances can be represented by means and standard deviations (or variances). The probabilistic characteristics of dynamic responses of constrained multi-body systems are obtained by two ways : the proposed analytical approach and the Monte Carlo simulation. The formerpaper, necessitates sensitivity information to calculate the standard deviations. In this a direct differentiation method is employed to find the sensitivities of constrained multi-body systems. To verify the accuracy of the proposed method, numerical examples are solved and the results obtained by using the proposed method are compared to those obtained by Monte Carlo simulation.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2006.05a
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• pp.1071-1078
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• 2006

Robust design of products or processes is a way to produce products or processes with less variability on condition that the product specification is met, so that the ratio of nonconforming products can be as minimized as possible. In such models as robust parameter design(RPD) originated by Taguchi and response surface methodology(RSM), the variances of noise variables are assumed to be measurable. However, there are circumstances in which the experimenters are unable to measure noise variables or perhaps are not aware of what the noise variables are. In this paper, it is demonstrated through an example that Taguchi's RPD approach can be conducted within the framework of the analysis of variability, with a view to a comparison of the two methods.

• The Journal of the Acoustical Society of Korea
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• v.14 no.6
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• pp.80-84
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• 1995

In the equivalent state with an actual transmission, the paper is presented the novel analysis of the dynamic characteristics of the automatic frequency control, using for QPSK relay system in digital land mobile communication, which is adopted a crass product frequency discriminator and the various kinds of frequency variances that calculate the closed loop frequency jitter are found.

• Korean Journal of Human Ecology
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• v.6 no.2
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• pp.41-48
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• 2003

The purpose of this research was to analyze the sexual discrimination level of woman employee in hotel industry. This research was based on a survey. The survey was conducted on 130 individuals who were working in hotels in Seoul. With collected data, regression analysts, T-Test and analysis of variances were utilized using SAS program. The results showed that there were no evidences of sexual discrimination among tile individuals' educational levels and the departments. Whereas, there were evidences of sexual discrimination, sexual harassment. discrimination against employment, and workload among the position levels within a corporation. Finally. the analysis showed that there were sexual discrimination in a promotion policy. retirement policy. workload. and employment during employment period. However, there were no evidences of sexual discrimination in ether areas.

• MALSORI
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• no.43
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• pp.179-188
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• 2002

Improving the recognition performance of connected digit telephone speech still remains a problem to be solved. As a basic study for it, this paper analyzes the variation of feature parameters of Korean digit telephone speech according to channel distortion. As a feature parameter for analysis and recognition MFCC is used. To analyze the effect of telephone channel distortion depending on each call, MFCCs are first obtained from the connected digit telephone speech for each phoneme included in the Korean digit. Then CMN, RTCN, and RASTA are applied to the MFCC as channel compensation techniques. Using the feature parameters of MFCC, MFCC+CMN, MFCC+RTCN, and MFCC+RASTA, variances of phonemes are analyzed and recognition experiments are done for each case. Experimental results are discussed with our findings and discussions

• The Journal of Korea Robotics Society
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• v.3 no.4
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• pp.308-314
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• 2008

Recently, simultaneous localization and mapping (SLAM) approaches employing Rao-Blackwellized particle filter (RBPF) have shown good results. However, no research is conducted to analyze the result representation of SLAM using RBPF (RBPF-SLAM) when particle diversity is preserved. After finishing the particle filtering, the results such as a map and a path are stored in the separate particles. Thus, we propose several result representations and provide the analysis of the representations. For the analysis, estimation errors and their variances, and consistency of RBPF-SLAM are dealt in this study. According to the simulation results, combining data of each particle provides the better result with high probability than using just data of a particle such as the highest weighted particle representation.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.20 no.9
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• pp.2909-2915
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• 1996

Precise and accurate pressure measurements are obtained using deadweight piston gauges. Pressure distribution and elastic distortion in the piston-cylinder unit are the leading factors in determination of effective area. The distortion depends upon the pressure distribution in the clearance between piston and cylinder and those are coupled each other. Considering the viscosity pressure relation of oil and governing flow equation in the clearance, a new numerical iterative algorithm is developed. The disagreement between the monotonous and sharp pressure profiles is an indication that the pressure profile will be different for each piston and cylinder unit due to material variances.