• Proceedings of the KIPE Conference
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• 2005.07a
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• pp.61-63
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• 2005

Utility interactive photovoltaic systems is one of the most premising applications of photovoltaic systems. These systems are employed in applications where utility service is already available. In this case, there is no need for battery storage because utility power may be used to supplement photovoltaic systems when the load exceeds available PV generation. The load receives electricity from both the photovoltaic array and the utility inter-tied. In this paper, Principle and operating characteristic of Utility Interconnected Photovoltaic System is presented. For the purpose of optimal utility Inter-tied photovoltaic system design and installation. It is that demonstrate throughout the installed 3 PV system respectively, 3kW utility interconnected residential system.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2013.11a
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• pp.11-12
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• 2013

It is required to response to the demand for new space due to high density of population and buildings in urban area. In particular, in case of big cities such as Seoul where the lack of new construction site due to the depletion of available space, existing buildings must be demolished for new construction. Utilization of urban underground space can be an alternative to solve for urban space problems. There are applications of underpinning methods using micropiles for existing buildings. Sometimes, the difficulties come from the compact space available for new foundation underneath the existing ones. In this paper, a novel underpinning method is introduced which can solve the space restriction problems underneath existing columns.

• Nuclear Engineering and Technology
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• v.29 no.1
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• pp.7-14
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• 1997

Grain boundary diffusion plays a significant role in fission gas release, which is one of the crucial processes dominating nuclear fuel performance. Gaseous fission produce such as Xe and Kr generated during nuclear fission have to diffuse in the grain lattice and the boundary inside fuel pellets before they reach the open spaces in a fuel rod. These processes can be studied by 'tracer diffusion' techniques, by which grain boundary diffusivity can be estimated and directly used for low burn-up fission gas release analysis. However, only a few models accounting for the both processes are available and mostly handle them numerically due to mathematical complexity. Also the numerical solution has limitations in a practical use. In this paper, an approximate analytical solution in case of stationary grain boundary in a polycrystalline solid is developed for the tracer diffusion techniques. This closed-form solution is compared to available exact and numerical solutions and it turns out that it makes computation not only greatly easier but also more accurate than previous models. It can be applied to theoretical modelings for low bum-up fission gas release phenomena and experimental analyses as well, especially for PIE (post irradiation examination).

• 한국전산유체공학회:학술대회논문집
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• 2001.10a
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• pp.118-125
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• 2001

The performance prediction of SMART MCP was performed using a computational fluid dynamics code. General capacity-head performance curve of MCP, which is provided to other design branches as design input, was obtained and it showed the typical type of axial pump performance curve. When four MCPs operate in parallel and one of them stops while the others continue to operate, SMART requires reduced power operation. A procedure for predicting the performance of SMART MCP for that case was developed and verified with available experimental data. An analysis based on the developed procedure was performed for two cases; the impeller of sloped MCP is fixed or free to rotate in reverse direction. According to the results, $73\%$ flow rate of normal operation enters the reactor core in the case of the locked impeller. In case of the impeller free rotation, the flow rate entering the reactor core is $62.8\%$.

• Smart Structures and Systems
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• v.6 no.9
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• pp.1057-1077
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• 2010

An early detection of structural damages is critical for the decision making of repair and replacement maintenance in order to guarantee a specified structural reliability. Consequently, the structural damage detection, based on vibration data measured from the structural health monitoring (SHM) system, has received considerable attention recently. The traditional time-domain analysis techniques, such as the least square estimation (LSE) method and the extended Kalman filter (EKF) approach, require that all the external excitations (inputs) be available, which may not be the case for some SHM systems. Recently, these two approaches have been extended to cover the general case where some of the external excitations (inputs) are not measured, referred to as the adaptive LSE with unknown inputs (ALSE-UI) and the adaptive EKF with unknown inputs (AEKF-UI). Also, new analysis methods, referred to as the adaptive sequential non-linear least-square estimation with unknown inputs and unknown outputs (ASNLSE-UI-UO) and the adaptive quadratic sum-squares error with unknown inputs (AQSSE-UI), have been proposed for the damage tracking of structures when some of the acceleration responses are not measured and the external excitations are not available. In this paper, these newly proposed analysis methods will be compared in terms of accuracy, convergence and efficiency, for damage identification of structures based on experimental data obtained through a series of laboratory tests using a scaled 3-story building model with white noise excitations. The capability of the ALSE-UI, AEKF-UI, ASNLSE-UI-UO and AQSSE-UI approaches in tracking the structural damages will be demonstrated and compared.

• The Journal of Fisheries Business Administration
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• v.42 no.2
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• pp.85-96
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• 2011

Oliver flounder population density affect Oliver flounder growth and mortality rate. In laboratory pilot experiment, Oliver flounder growth rate is inversely proportional to stocking density. But previous study has not proved external validity. This study is aimed to analyze the effect of stocking density on the Oliver flounder culture farms in Jeju Island. In order to do this, I selected 13 farms in Jeju island as a sample. In the study, various analytical methods including productivity analysis, regression analysis, statistical analysis were conducted for 13 Oliver flounder culture farms. The result of analysis can be summarized as follows. First, in case of the Oliver flounder culture farms, Bertalanffy equation is not applicable to the Oliver flounder growth. Second, the Oliver flounder stocking density, defined as the surface area of Oliver flounder per $m^2$ of water surface area, is preferred to density definition defined as the weight of Oliver flounder per $m^2$ of water surface area on the Oliver Flounder Culture Farms case. Third, growth rate and production weight on the Oliver flounder culture farms are inversely proportional to stocking density on spearman rank correlation test. When extensive comparable biological and culture condition data become available, analysis model can be easily modified to yield more accurate results.

• Communications for Statistical Applications and Methods
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• v.29 no.1
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• pp.103-125
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• 2022

In this paper, we analyze the time series data of the case and death counts of COVID-19 that broke out in China in December, 2019. The study period is during the lockdown of Wuhan. We exploit functional data analysis methods to analyze the collected time series data. The analysis is divided into three parts. First, the functional principal component analysis is conducted to investigate the modes of variation. Second, we carry out the functional canonical correlation analysis to explore the relationship between confirmed and death cases. Finally, we utilize a clustering method based on the Expectation-Maximization (EM) algorithm to run the cluster analysis on the counts of confirmed cases, where the number of clusters is determined via a cross-validation approach. Besides, we compare the clustering results with some migration data available to the public.

• Journal of the Korean Mathematical Society
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• v.33 no.2
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• pp.235-247
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• 1996

Many numerical computations in science and engineering can only be solved approximately since the available infomation is partial. For instance, for problems defined ona space of functions, information about f is typically provided by few function values, $N(f) = [f(x_1), f(x_2), \ldots, f(x_n)]$. Knwing N(f), the solution is approximated by a numerical method. The error between the true and the approximate solutions can be reduced by acquiring more information. However, this increases the cost. Hence there is a trade-off between the error and the cost.

• 제어로봇시스템학회:학술대회논문집
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• 1991.10a
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• pp.493-497
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• 1991

A problem of analysis and design of asymptotically reliable serial production systems, closed with respect to the number of carriers that transport parts between operations, is addressed. A case study of a paint shop operation at a modern automobile assembly plant is described. The results obtained indicate that optimization of the system with respect to the number of carriers available and the capacity of the feedback buffer leads to a substantial improvement in the production rate.

• Nonlinear Functional Analysis and Applications
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• v.29 no.2
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• pp.545-558
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• 2024

In this study, a class of nonlinear boundary fractional Caputo Volterra-Fredholm integro-differential equations (CV-FIDEs) is taken into account. Under specific assumptions about the available data, we firstly demonstrate the existence and uniqueness features of the solution. The Gronwall's inequality, a adequate singular Hölder's inequality, and the fixed point theorem using an a priori estimate procedure. Finally, a case study is provided to highlight the findings.