• 한국입자에어로졸학회지
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• 제8권1호
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• pp.1-8
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• 2012

In this study, the collection efficiency of inertial impactors was numerically simulated by employing the statistical Lagrangian particle tracking(SLPT) model. The SLPT model was proven to be correct in predicting the impactor collection efficiency, when the numerically obtained collection efficiencies were compared with the experimental data of Marple et al.(1987) at normal pressure level and the experimental data of $Marjam{\ddot{a}}ki$ et al.(2000) at low pressure level. Based on the validation results, balloon-borne impactors with the cut-off sizes of $1{\mu}m$, $2.5{\mu}m$, and $10{\mu}m$ were designed. Then, the sampling flowrates of the inertial impactors, required to keep the cut-off sizes constant at different pressures and temperatures, were estimated according to the altitude.

• 산업공학
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• 제22권3호
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• pp.192-204
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• 2009

Based on the characteristics of 'Korean electric power industry R&D programs', this study proposes a new performance evaluation framework where electric power industry related R&D projects are scrutinized. The abovementioned R&D programs have their own goals and especially they emphasize the effectiveness as well as the efficiency of each subordinate R&D project. Hence, in this framework, a performance evaluation procedure is established and then a mathematical model is developed according to the procedure. The model calculates performance evaluation indices for a set of R&D projects integrating the effectiveness with the efficiency of each R&D project. In a case study with an empirical dataset, statistical significance is tested on the integrated performance evaluation indices of R&D projects regarding organizational types and program categories considered.

• 전기학회논문지P
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• 제55권4호
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• pp.155-160
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• 2006

In this paper, deduced suitable optimization to request output condition after taking closely characteristic data of single phase induction motor(SIM) which is the possibility becoming economic is coming to be demanded. Motor proper move connection data took advantage of result of existing data and iron loss and copper loss, mechanical loss took advantage of statistical data, and decide motor move laking advantage of saving data and secondary resistance and optimum purpose of method that is proposed through single phase induction motor and comparison performance evaluation having on the same output parameter. That decide material factor, electric power damage ratio, and coefficient of utilization for optimum function by method that search request output and optimum values of efficiency case by case and decided is proper that is saved after take magnetizing reactance relationship. This research result which it sees against a material expense with use coefficient of utilization which is included in loss expense decides the same plan variable back the place efficiency is useful and will be applied.

• 수산해양기술연구
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• 제50권3호
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• pp.262-273
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• 2014

To investigate the catching efficiency of a biodegradable round trap for a swimming crab (Portunus trituberculatus), four types of material (two types of biodegradable net, one type of biodegradable plus polyethylene net and one type of polyethylene net) for traps were used in the field test, and the field tests were carried out 11 times in the Boryeong fishing ground of Korea, 2012~2013. The catching efficiency of four type traps was analyzed by catch per trap, weight per trap and mean weight per individual of small and large size swimming crab. Statistical Kruskal-Wallis test was carried out to verify the significant difference for the efficiency between types of material. The catch in number of swimming crab was 9,015 and formed about 94.3% of total catch. In the results of catching efficiency of traps, there was a little difference in catch per trap, weight per trap and mean weight per individual of swimming crab in-situ data. But there was no significant difference in catching efficiency between the biodegradable traps and the PE trap (P>0.05), so it's needed to use widely a biodegradable trap for the conservation and sustainable management of swimming crab resources.

• 동아시아경상학회지
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• 제9권2호
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• pp.1-10
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• 2021

Purpose - The purpose of this study is to measure the efficiency of social security expenditure in 31 provinces, cities and autonomous regions in China and proposes corresponding improvement plans. Research design, data, and methodology - The data were obtained from the statistical yearbook of each province. The BCC and CCR models of DEA model and Malmquist index are used to analyze the efficiency, and the input-output index is expanded. Result - The results show that the social security performance of the Chinese government has improved on the whole despite the unbalanced development in different regions. Each region should look for strategies to improve the efficiency of social security according to its own problems. The study suggests that provinces affected by TCI should improve their internal environment, such as raising social security fund structure and strengthening fund supervision, to improve efficiency. Areas affected by TECI need to be more responsive to policy, socio-economic and technological development. Conclusion - The research conclusion can provide reference for Chinese provinces to improve the efficiency of social security expenditure in the future. This study is not comprehensive enough in the selection of input-output indicators, which can be further expanded in the future.

• Communications for Statistical Applications and Methods
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• 제22권6호
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• pp.639-646
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• 2015

We propose simultaneous tests for mean and variance under the normality assumption. After formulating the null hypothesis and its alternative, we construct test statistics based on the individual p-values for the partial tests with combining functions and derive the null distributions for the combining functions. We then illustrate our procedure with industrial data and compare the efficiency among the combining functions with individual partial ones by obtaining empirical powers through a simulation study. A discussion then follows on the intersection-union test with a combining function and simultaneous confidence region as a simultaneous inference; in addition, we discuss weighted functions and applications to the statistical quality control. Finally we comment on nonparametric simultaneous tests.

• 한국석유지질학회:학술대회논문집
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• 한국석유지질학회 1998년도 제5차 학술발표회 발표논문집
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• pp.10-14
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• 1998

A systematic methodology is developed for the electrofacies determination from wireline log data using multivariate statistical analysis. To consider corresponding contribution of each log and reduce the computational dimension, multivariate logs are transformed into a single variable through principal components analysis. Resultant principal components logs are segmented using the statistical zonation method to enhance the efficiency and quality of the interpreted results. Hierarchical cluster analysis is then used to group the segments into electrofacies. Optimal number of groups is determined on the basis of the ratio of within-group variance to total variance and core data. This technique is applied to the wells in the Korea Continental Shelf. The results of field application demonstrate that the prediction of lithology based on the electrofacies classification matches well to the core and the cutting data with high reliability This methodology for electrofacies classification can be used to define the reservoir characteristics which are helpful to the reservoir management.

• 환경정책연구
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• 제2권2호
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• pp.81-103
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• 2003

This paper compares the environmental economic performance of the South Korean and the German economy during the last decade. The analysis is based on comparable data from the Environmental Economic Accounts (EEA). The EEA is a satellite account to the National Accounts which enhances the conventional economic accounts by a description of the interactions between the economy and the environment. The data from the EEA and the national accounts are fully compatible. In absolute terms the environmental pressures caused by economic activities were with regards to the environmental factors used for the analysis generally lower in South Korea than in Germany. If the use of environmental factors is related to each country's gross domestic product (environmental productivities) a lower level of environmental productivity can be observed for most of the environmental factors in South Korea compared to Germany. For example in 1999 energy and $CO_2$ productivity were about two fifths of the German level. This corresponds to the relation regarding labour productivity (Gross domestic product per employment).

• 한국지진공학회:학술대회논문집
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• 한국지진공학회 2001년도 추계 학술발표회 논문집 Proceedings of EESK Conference-Fall 2001
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• pp.243-250
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• 2001

Industrial machines are sometimes exposed to the danger of earthquake. In the design of a mechanical system, this factor should be accounted for from the viewpoint of reliability. A method to analyze a complex nonlinear structure system under random excitation is proposed. First, the actual random excitation, such as earthquake, is approximated to the corresponding Gaussian process far the statistical analysis. The modal equations of overall system are expanded sequentially. Then, the perturbed equations are synthesized into the overall system and solved in probabilistic way. Several statistical properties of a random process that are of interest in random vibration applications are reviewed in accordance with nonlinear stochastic problem. The obtained statistical properties of the nonlinear random vibration are evaluated in each substructure. Comparing with the results of the numerical simulation proved the efficiency of the proposed method.

• Journal of the Korean Statistical Society
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• 제28권1호
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• pp.93-106
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• 1999

In this paper we consider estimation of a real valued parameter in the drift coefficient of a Hilbert space valued Ito stochastic differential equation. First we consider observation of the corresponding diffusion in a fixed time interval [0, T] and prove the Bernstein - von Mises theorem concerning the convergence of posterior distribution of the parameter given the observation, suitably normalised and centered at the MLE, to the normal distribution as Tlongrightarrow$\infty$. As a consequence, the Bayes estimator of the drift parameter becomes asymptotically efficient and asymptotically equivalent to the MLE as Tlongrightarrow$\infty$. Next, we consider observation in a random time interval where the random time is determined by a predetermined level of precision. We show that the sequential MLE is better than the ordinary MLE in the sense that the former is unbiased, uniformly normally distributed and efficient but is latter is not so.