• Journal of Korean Society of Rural Planning
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• v.22 no.4
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• pp.147-157
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• 2016

On the purpose to analyze the survival rate of startup companies since their establishment, the companies' survival rate was investigated by surviving period. The average and coefficient of variation(C.V.) of the startup companies' survival rate were examined with the comparison of urban and rural areas, and primary, secondary, and tertiary industries. In this study, the variation of total numbers of new-established companies, from 1998 to 2012, were analyzed with micro-data of the Statistics Korea, 'The Census on Establishments'. The results show that the survival rate of primary industry companies largely fluctuate and don't be stabled during the whole surviving periods, whereas secondary and tertiary industry companies show stabilized survival rate after fifth year from their establishment. Especially, the startup companies of primary industry located at urban areas show the largest fluctuation and the most vulnerable stability of survival rate. It is concluded that the surviving period of primary industry companies don't guarantee their survival, while survival rate of secondary and tertiary industry company became stable after five years from their establishment.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.23 no.3
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• pp.24-38
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• 1997

Using the all-trans-retinol which is double-capsulated with matrix, we investigated its stability and the change of the epidermal thickness. The proprietary MDC comprise two steps of capsulation of retinol, i.e., primary microcapsulation with collagen and then secondary capsulation with gellan gum. We compared the activity of all-trans-retinol in various forms such as (1) simply in O/W, (2) in W/O emulsion, (3) in primary capsulted form in O/W emulsion, or (4) in MDC in O/W emulsion. After storage at 45$^{\circ}C$ for 4 weeks, retinol in MDC in O/W emulsion retained 92% of the activity compared to the standard material upon HPLC analysis, whereas the primary capsule gave 70%, the O/W emulsion form 47% and the W/O emulsion 78%. The retinol in MDC in O/W induced the siginificant increase in epidermal thickness compared to the vehicle.

• Journal of Communications and Networks
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• v.17 no.3
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• pp.265-266
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• 2015

In a recent paper [1], the authors investigated the maximum stable throughput region of a network composed of a rechargeable primary user and a secondary user plugged to a reliable power supply. The authors studied the cases of an infinite and a finite energy queue at the primary transmitter. However, the results of the finite case are incorrect. We show that under the proposed energy queue model (a decoupled M/D/1 queueing system with Bernoulli arrivals and the consumption of one energy packet per time slot), the energy queue capacity does not affect the stability region of the network.

• Proceedings of the KSR Conference
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• 2006.11b
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• pp.98-103
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• 2006

The hunting is the natural characteristics of the railway wheelset which is originated from the contact between the conical type wheel profile and rail. The critical speed of rolling-stock is called when the hunting is occurred, and it is closely connected with vehicle stability. The parameters which influence the hunting motion are like wheel profile, primary spring property and wheelset dimension, etc. The studies for these parameters are reported diversely. In this study, we aim to analyze the influence of parameters on hunting with the change of wheel profile produced by wheel wear and material property produce by aging of primary spring. For this, we made a dynamic model for wheelset and vehicle. Using these models, we analyzed the critical speed with the variations of the parameters like as wheel profile and primary spring property and we show the results.

• 대한치주과학회:학술대회논문집
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• 2005.11a
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• pp.69-69
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• 2005

• Communications of the Korean Mathematical Society
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• v.34 no.1
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• pp.113-125
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• 2019

In this paper, we introduce the elimination ideal $I_D(G)$ associated to a simple finite graph G. We obtain the upper bound of Castelnuovo-Mumford regularity of elimination ideal for various classes of graphs.

• Proceedings of the Korean Geotechical Society Conference
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• 2002.11b
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• pp.103-114
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• 2002

Stability of cut-slope is considered to have a deep relationship with rock types since rock has its own engineering and geological characteristic such as shear strength, durability, weathering profile, geological structures. Therefore, analysis of geological and engineering characterisics of rock mass is essential for the evaluation of rock slope stability This paper introduces the statistical data of slope failure cases which was collected from highway slopes constructed in sedimentary rock mainly of shale in Ky ng-sang Basin. Primary failure feature in this area is planar failure along the bedding regardless of slope geometry. Even a disasterous slope failure case due to the thick clay layer between the beddings was reported. Failures and rock fall were reported to ocurred frequently after the completion of cutting due to the weathering, so long-term slope stability should be considered as a important factors in design.

• Proceedings of the Korean Geotechical Society Conference
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• 1999.03a
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• pp.339-346
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• 1999

The stability of rock slope is considered to have a deep relation with types of rocks because types of rocks have their own typical weathering profiles, geological structures and characteristics of failures. Therefore it is essential for the evaluation of rock slope stability to analyze geological and engineering characteristics in rock mass. The data which collected from investigated slopes in sedimentary rock of Kyengsang Basin along highways were analyzed. Primary factors affecting slope stability in rock mass are: dips and strikes of slopes and discontinuities, shear strength of discontinuities, slope geometry and geological structures etc.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2000.04b
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• pp.85-91
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• 2000

The smallest value of the load when the equilibrium condition becomes to be unstable is defined as the buckling load. The primary objective of this paper is to analyse stability boundaries for star dome under combined loads and is to investigate the iteration diagram under the independent loading parameter In numerical procedure of the geometrically nonlinear problems, Arc Length Method and Newton-Raphson iteration method is used to find accurate critical point(bifurcation point and limit point). In this paper independent loading vector is combined as proportional value and star dome was used as numerical analysis model to find stability boundary among load parameters and many other models as multi-star dome and arches were studied. Through this study we can find the type of buckling mode and the value of buckling load.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.11 no.8
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• pp.314-321
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• 2001

Static and oscillatory loss of stability of composite pipes conveying fluid is Investigated. The theory of than walled beams is applied and transverse shear. rotary inertia, primary and secondary warping effects are incorporated. The governing equations and the associated boundary conditions are derived through Hamilton's variational principle. The governing equations and the associated boundary conditions are transformed to an eigenvlaue problem which provides the Information about the dynamic characteristics of the system. Numerical analysis is performed by using extended Gelerkin method. Variation of critical velocity of fluid with fiber angles and mass patios of fluid to pipe Including fluid is investigated.