• Journal of the Korean Society for Precision Engineering
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• v.21 no.1
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• pp.173-180
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• 2004

This paper presents the effect of varying boundary conditions such as ground subsidence, internal pressure and temperature variation for buried pipelines on failure prediction by using a failure probability model. The first order Taylor series expansion of the limit state function incorporating with von-Mises failure criteria is used in order to estimate the probability of failure mainly associated with three cases of ground subsidence. Using stresses on the buried pipelines, we estimate the probability of pipelines with von-Mises failure criterion. The effects of varying random variables such as pipe diameter, internal pressure, temperature, settlement width, load for unit length of pipelines, material yield stress and pipe thickness on the failure probability of the buried pipelines are systematically studied by using a failure probability model for the pipeline crossing ground subsidence regions which have different soil properties.

• Tribology and Lubricants
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• v.15 no.3
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• pp.233-239
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• 1999

Generally quantity of supply oil for piston ring lubrication in an internal combustion engine may be insufficient to fill the entire volume formed in the clearance between piston ring and cylinder liner. Thus oil starvation condition should be considered for the analysis of piston ring lubrication. In order to reasonably estimate amount of oil left on the cylinder liner, adequate boundary condition should be adapted for the analysis of ring pack lubrication. In this analysis of ring pack lubrication of an internal combustion engine, oil starvation and open-end boundary conditions are considered at inlet and outlet of piston rings. It is revealed that piston rings are operated under oil starvation in most operating cycle and the result with these conditions are quite different from that with fully-flooded assumption.

• Journal of KSNVE
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• v.8 no.1
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• pp.122-131
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• 1998

Internal and external acoustic fields of the engine inlet are calculated by using a finite element method. The far fields non reflecting boundary condition is enforced by using a wave envelope element, which is a kind of infinite element. The geometry is assumed an axisymetric duct. Sources of the fan are modeled by the Tyler and Sofrin's theory. Effects of uniformly moving medium are considered. A pulsating sphere and an oscillating piston problem are calculated to verify the external problems, and compared with exact solutions. When the wave envelope element is applied at the far boundary, the calculated finite element solutions show good agreements with the exact solutions. The engine inlet is solved with the combined internal and external grid. The cut-off phenomena on engine inlet duct are observed.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.77.4-77
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• 2001

The quality of agricultural products is classified with various factors which are measured and determined by destructive and/or nondestructive method. NIR spectrum analysis method is used to determine internal qualities such as a brix and an acidity. CCD color camera is used to measure external quality like color and a size of fruit. today, nondestructive methods are widely researched. The quality and the garde of fruit loaded into a cup automatically and measured in real time by camera and NIR system is determined by internal and external factors. This paper proposes modified boundary tracking algorithm which detects the contour of fruit´s color image and make chain code faster than conventional method ...

• Knowledge Management Research
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• v.16 no.1
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• pp.171-191
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• 2015

This paper investigates how internal knowledge dependency and its interaction with external knowledge adoption affect innovation performance in Korean companies. We categorize innovation performance into exploratory innovation and exploitative innovation. Especially, we examine business group effects as group headquarters and sister subsidiaries holistically form the boundary of the firm. Our empirical results first suggest that the degree of internal knowledge dependency is positively associated with exploitative innovation, but negatively with exploratory innovation. Second, internal knowledge dependency is more negatively related to exploratory innovation in independent firms than in business group affiliates. Third, independent firms' adoption of external knowledge tends to strengthen the positive relationship between internal knowledge dependency and exploitative innovation. Finally, exploitative external knowledge search appears to strengthen the negative relationship between internal knowledge dependency and exploratory innovation in both types of firms.

• Journal of Mechanical Science and Technology
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• v.15 no.5
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• pp.555-561
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• 2001

A new approach to analyze the multi-domain acoustic system divided and enclosed by flexible structures is presented in this paper. The boundary element formulation of the Helmholtz integral equation is used for the internal fields and the finite element formulation for the structures surrounding the fields. We developed a numerical analysis program for the structural-acoustic coupling problems of the multi-domain system, in which boundary conditions such as the continuity of normal particle velocity and sound pressure in the structural interfaces between Field 1 and Field 2 are not needed. The validity of the numerical analysis program is verified by comparing the numerical results with the experimental ones. Example problems are included to investigate the characteristics of the coupled multi-domain system.

• Journal of Mechanical Science and Technology
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• v.16 no.10
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• pp.1320-1326
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• 2002

In a one-dimensional heat conduction domain with heated and insulated walls, an integral approach is proposed to estimate time-dependent boundary heat flux without internal measurements. It is assumed that the expression of the heat flux is not known a priori. Hence, the present inverse heat conduction problem is classified as a function estimation problem. The spatial temperature distribution is approximated as a third-order polynomial of position, whose four coefficients are determined from the heat fluxes and the temperatures at both ends at each measurement. After integrating the heat conduction equation over spatial and time domain, respectively, a simple and non-iterative recursive equation to estimate the time-dependent boundary heat flux is derived. Several examples are introduced to show the effectiveness of the present approach.

• Journal of the Korean Mathematical Society
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• v.47 no.6
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• pp.1223-1238
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• 2010

The purpose of this work is to identify the internal structure of the electrical networks with data obtained from only a part of network or the boundary of network. To be precise, it is discussed whether we can identify resistors or electrical conductivities of each link inside networks by the measurement of voltage on the boundary which is induced by a prescribed current on the boundary. As a result, it is shown that the structure of the resistor network can be determined uniquely by only one pair of the data (current, voltage) on the boundary, if the resistors satisfy an appropriate condition. Besides, several useful results about the energy functionals, which means the electrical power, are included.

• Journal of Korean Academy of Nursing Administration
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• v.19 no.1
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• pp.17-27
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• 2013

Purpose: This study was done to explore how nurses manage the boundary for work-family balance. Methods: Data were collected through in-depth interviews from February 1 to May 28, 2012. Participants were 13 married nurses with children. The constant comparative method was adapted for data analysis. Results: In this study, nurses' work-family boundary management had characteristics of integration, maintenance and control, but it was adjusted and modified over time as the order of priorities was rearranged according to changes in internal cognition and family support. Nurses strategically persuaded their families to understand their work and share housework in an effort to integrate work and family, while controlling them by managing working hours and time for themselves. Conclusion: The results of the study indicate that nurses' work has an impact on family life due to heavy workload and insufficient time, however the work-family balance can be successfully maintained with the effective separation of the two areas.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1988.10a
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• pp.49-54
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• 1988

A procedure which may be useful in dealing with problems of half plane is considered. Boundary elements are combined with finite elements to facilitate their merits. Boundary elements for semi-infinite region are composed using the Melan's solution for half plane. Finite elements are used to model irregurarity or the nonhomogeneity of materials, which is usual in underground structures. In order to verify the procedure, a shallow tunnel under internal pressure is analysed using the finite element method, the boundary element method, and the combined method. It is shown that the developed Procedure is accurate enough compared with other method.