• Journal of the Korean Mathematical Society
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• v.51 no.4
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• pp.735-749
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• 2014

This paper studies the asymptotic behavior of the finite-time ruin probability in a jump-diffusion risk model with constant force of interest, upper tail asymptotically independent claims and a general counting arrival process. Particularly, if the claim inter-arrival times follow a certain dependence structure, the obtained result also covers the case of the infinite-time ruin probability.

• Strategy21
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• s.39
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• pp.198-241
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• 2016

Aircraft carriers: are they national platforms to maximize national interest or just simply paper tigers to be little useful for states' development? To some states such as U.S., U.K, and France, aircraft carriers functioned as national assets which is indispensable to their interest. By contrast, Thailand's aircraft carrier was a dead platform which is useless to its national interest and India's ones were little used on the mission field. What is the mechanism leading to this difference? The key is whether states make aircraft carriers connected to overall national evolution when it comes to establishing military strategy and planning a long-term force structure. Put it another way, conditions to acquire them need to be analyzed regarding two variables-national status(prestige and economic power) and threat(mission)-for the future as well as in the present. The former acquired carriers under the condition of making them becoming national platforms which is balanced with their overall development. However, the latter simply bought them without carefully taking account of economic obstacles, e.g., the poverty rate, when it comes to force planning. At the same time, we should not neglect to identify that states of the former cases might have a hard time in maximizing their key interests if they did not have carriers. Accordingly, conditions on carriers' acquisition need to be carefully examined and a typological theory suggested here could shed light on this process. This theory shows that South Korea's status is eligible to have a necessary and sufficient condition to acquire carriers.

• Journal of applied mathematics & informatics
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• v.23 no.1_2
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• pp.87-99
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• 2007

In this paper, we consider the Sparre Andersen risk model modified by the inclusion of interest on the surplus. By using the techniques of Cai and Dickson [Ins.: Math. Econ. 32(2003)], we give the functional and also the exponential type upper bounds for the tail probability of the deficit at ruin. Some special cases are also discussed.

• Journal of the Korean Society of Safety
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• v.19 no.2
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• pp.88-92
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• 2004

The paper decribes a procedure for the evaluation of the effect of seepage force on stability of slopes. The stability of an embankment impounding a water reservoir is highly depend upon the location of seepage line with the embankment. To evaluate the accurate safety factor of an embankment, it is important to illustrate the seepage phenomenon. Of particular interest is the stability following a rapid change of reservoir level. Seepage forces in embankments are easily determined interest is the stability following a rapid change of resrvoir level. Seepage forces in embankments are easily detemined if frictional forces are expressed in relation to hydraulic gradient I. If a piezometer is inserted into a body of embankment, the level to which fee water rises is a measure of the energy at that point.

• Bulletin of the Korean Mathematical Society
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• v.50 no.2
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• pp.611-626
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• 2013

In the paper we study the finite-time ruin probability in a general risk model with constant interest force, in which the claim sizes are pairwise quasi-asymptotically independent and arrive according to an arbitrary counting process, and the premium process is a general stochastic process. For the case that the claim-size distribution belongs to the consistent variation class, we obtain an asymptotic formula for the finite-time ruin probability, which holds uniformly for all time horizons varying in a relevant infinite interval. The obtained result also includes an asymptotic formula for the infinite-time ruin probability.

• Bulletin of the Korean Mathematical Society
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• v.52 no.3
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• pp.895-906
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• 2015

Recently, Li [12] gave an asymptotic formula for the ultimate ruin probability in a delayed-claim risk model with constant force of interest and pairwise quasi-asymptotically independent and extended-regularly-varying-tailed claims. This paper extends Li's result to the case in which the risk model is perturbed by diffusion, the claims are consistently-varying-tailed and the main-claim interarrival times are widely lower orthant dependent.

• Advances in biomechanics and applications
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• v.1 no.4
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• pp.227-237
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• 2014

The in vitro construction of osteo-articular large implants combining biomaterials and cells is of great interest since these tissues have limited regeneration capability. But the development of such organoids is particularly challenging, especially in the later time of the culture, when the extracellular matrix has almost filled the initial porous network. The fluid flow needed to efficiently perfuse the sample can then not be achieved using only the hydraulic driving force. In this paper, we investigate the interest of using an electric field to promote mass transport through the scaffold at the late stage of the culture. Based on the resolution of the electrokinetics equations, this study provides an estimation of the necessary electric driving force to reach a sufficient oxygen perfusion through the sample, thus analyzing the feasibility of this concept. The possible consequences of such electric fields on cellular activities are then discussed.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.10a
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• pp.181-184
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• 2002

In these day, fabrication technologies for micro parts become more important with the increase of interest on microsystem and developed through the various approaches in the whole world. Among these technologies; micro mechanical machining is one of the most effective methods for the fabrication of micro parts. In this study, we fabricated micro shafts using micro endmill and micromachining system and measured the cutting force at the process. Also, Based on the data, we simulated the deformation of micro shafts due to the cutting force. Through the simulation results, it was verified that the cutting force at the process is enough to cause dimensional error at the micro shafts.

• Smart Structures and Systems
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• v.12 no.3_4
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• pp.381-397
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• 2013

In this paper, wireless health monitoring of stay cables using piezoelectric strain sensors and a smart skin technique is presented. For the cables, tension forces are estimated to examine their health status from vibration features with consideration of temperature effects. The following approaches are implemented to achieve the objective. Firstly, the tension force estimation utilizing the piezoelectric sensor-embedded smart skin is presented. A temperature correlation model to recalculate the tension force at a temperature of interest is designed by correlating the change in cable's dynamic features and temperature variation. Secondly, the wireless health monitoring system for stay cables is described. A piezoelectric strain sensor node and a tension force monitoring software which is embedded in the sensor are designed. Finally, the feasibility of the proposed monitoring technique is evaluated on stay cables of the Hwamyung Grand Bridge in Busan, Korea.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.32 no.1
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• pp.20-24
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• 2019

Ferroelectric material properties are strongly governed by domain structures and their evolution processes, but the evolution processes of complex domain patterns during a macroscopic electrical poling process are still elusive. In the present work, domain-evolution processes in a PZT ceramic near the morphotropic phase-boundary composition were studied during a step-wise electrical poling using piezoresponse force microscopy (PFM). Electron backscatter diffraction was used with the PFM data to identify the grain boundaries in the region of interest. In response to an externally the applied electric field, growth and retreat of non-$180^{\circ}$ domain boundaries wasere observed. The results indicate that ferroelectric polarization-switching nucleates and evolves in concordance with the pattern of the pre-existing domains.