• 산업경영시스템학회지
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• 제30권4호
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• pp.164-169
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• 2007

The estimation of mortality characteristics of industrial property is an important adjunct to engineering valuation and depreciation estimation. Once the important of depreciation estimation is determined, it is desirable to understand the processes upon which these estimates are based. The Iowa type survivor curves are a set of generalized retirement dispersion models. These curves were based on analysis of actual retirement experience and represent typical retirement behavior patterns likely to be encountered. The retirement rate of Iowa type survivor curves on the semiconductor equipments in Korea industry was estimated by the life estimation process. In this paper, estimates of service lives based on directly observed data of the domestic semiconductor equipments are presented.

• 비파괴검사학회지
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• 제23권6호
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• pp.605-615
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• 2003

In practice, it is common to manufacture reference blocks containing simple reflectors to obtain distance-amplitude correction (DAC) curves. However, the construction or DAC curves in this manner requires the use of a large number of specimens with appropriate curvatures and reference reflectors located at various depths. Therefore, less costly and quantitative procedures are strongly needed. To address such a need, in this study, we have developed model-based transfer curves to relate a DAC curve obtained in a particular reference configuration with that for a completely different configuration. An example of transferring DAC curves, using the proposed transfer curves, is given.

• 한국도로학회논문집
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• 제11권1호
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• pp.1-12
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• 2009

폼드아스팔트를 이용한 현장 상온 재생아스팔트 혼합물에 대한 배합설계법이 아이오아 주 교통국에서 사용하기 위해 개발되었다. 상온 재생 폼드아스팔트 혼합물의 배합설계를 위한 실내시험절차를 개선하기 위하여 배합설계에 영향을 미치는 중요한 배합설계변수들을 결정하여 상온 재생 폼드아스팔트 혼합물의 특성을 반영할 수 있는 새로운 배합설계절차를 개발하였다. 개발된 배합설계법의 검증을 위한 한 가지 방법으로 상온 재생 폼드아스팔트 혼합물의 동탄성계수를 측정하였다. 본 연구에서는 새로운 simple performance testing 장비를 이용한 상온 재생 폼드아스팔트 혼합물의 동탄성계수 측정을 위한 표준시험절차를 정립하고, 7가지 재생 아스팔트 골재를 사용하여 생산된 상온 재생 폼드아스팔트 혼합물의 동탄성 계수를 측정하여 마스터곡선을 작성하였다. 또한 재생 아스팔트 골재의 특성이 상온 재생 폼드아스팔트혼합물의 동탄성 계수에 미치는 영향을 조사하였다. 3가지 온도와 6가지의 하중주기에서 측정된 상온 재생 폼드아스팔트 혼합물의 동탄성계수는 7가지 재생 아스팔트 골재에서 일관된 값을 나타내었으며, 작성된 상온 재생 폼드아스팔트 혼합물의 마스터곡선은 가열 아스팔트 혼합물의 마스터곡선에 비해 하중주기에 대해 덜 민감한 것으로 평가되었다. 저온에서는 재생 아스팔트 골재의 잔골재 함유량이 상온 재생 폼드아스팔트 혼합물의 동탄성계수에 영향을 미치는 것으로 나타났으며, 고온에서는 재생 아스팔트 골재의 잔류 아스팔트 특성이 상온 재생 폼드아스팔트 혼합물의 동탄성계수에 영향을 미치는 것으로 나타났다.

• 산업경영시스템학회지
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• 제29권1호
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• pp.143-150
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• 2006

Box-Cox model and T-factor method have been widely used to measure economic depreciations for industrial property. The Box-Cox model which combines economic efficiency with depreciation pattern is here extended to the reliability function. To do so a Rayleigh distribution which has been used to estimate the reliability of current assets was chosen as an efficiency curve of marginal productivity. Such an approach provides the possibility to classify the efficiency curves into four categories. It is also possible to analyze the types of depreciation curves. Therefore, the power family of a non-linear Box-Cox model could be set at certain constant values, then the model can be transformed into a linear model to estimate the economic depreciation rates by utilizing the reliability function. Estimating the resultant linear regression equation requires minimal number of observations, while at the same time facilitating the test of hypothesis on depreciation rates.

• 산업경영시스템학회지
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• 제30권1호
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• pp.66-73
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• 2007

일반 투자안의 의사결정에서와 마찬가지로 산업설비의 경제성 분석에서도 가장 중요한 결정 요소 중의 하나가 설비의 생존곡선 추정이다. 설비의 자산 가치가 감소하는 원인은 여러 가지가 있으나, 여러 원인 중 물리적 훼손이 과거의 산업설비에서는 가장 중요한 원인이었으므로 기존의 생존모형 분석에서는 lows 생존곡선을 이용하여 설비의 생존곡선을 추정하였다. 그러나 새로운 기술상의 변화로 인한 첨단 생산시스템의 설비교체 분석 시에는 적합지 않다. 따라서, 본 연구에서 제안된 혼합형 Weibull 함수를 이용하여 설비의 폐기 형태를 추정함으로써 설비들의 실제적인 생존곡선을 정확하게 파악할 수 있다.

• BMB Reports
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• 제35권2호
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• pp.143-154
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• 2002

The structural and functional aspects of ervatamin B were studied in solution. Ervatamin B belongs to the $\alpha+\beta$ class of proteins. The intrinsic fluorescence emission maximum of the enzyme was at 350 nm under neutral conditions, and at 355 nm under denaturing conditions. Between pH 1.0-2.5 the enzyme exists in a partially unfolded state with minimum or no tertiary structure, and no proteolytic activity. At still lower pH, the enzyme regains substantial secondary structure, which is predominantly $\beta$-sheet conformation and shows a strong binding to 8-anilino-1-napthalene-sulfonic acid (ANS). In the presence of salt, the enzyme attains a similar state directly from the native state. Under neutral conditions, the enzyme was stable in urea, while the guanidine hydrochloride (GuHCl) induced equilibrium unfolding was cooperative. The GuHCl induced unfolding transition curves at pH 3.0 and 4.0 were non-coincidental, indicating the presence of intermediates in the unfolding pathway. This was substantiated by strong ANS binding that was observed at low concentrations of GuHCl at both pH 3.0 and 4.0. The urea induced transition curves at pH 3.0 were, however, coincidental, but non-cooperative. This indicates that the different structural units of the enzyme unfold in steps through intermediates. This observation is further supported by two emission maxima in ANS binding assay during urea denaturation. Hence, denaturant induced equilibrium unfolding pathway of ervatamin B, which differs from the acid induced unfolding pathway, is not a simple two-state transition but involves intermediates which probably accumulate at different stages of protein folding and hence adds a new dimension to the unfolding pathway of plant proteases of the papain superfamily.

• Asian-Australasian Journal of Animal Sciences
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• 제24권1호
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• pp.17-27
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• 2011

A selection experiment for reduced residual feed intake (RFI) in Yorkshire pigs consisted of a line selected for lower RFI (LRFI) and a random control line (CTRL). Longitudinal measurements of daily feed intake (DFI) and body weight (BW) from generation 5 of this experiment were used. The objectives of this study were to evaluate the use of random regression (RR) and nonlinear mixed models to predict DFI and BW for individual pigs, accounting for the substantial missing information that characterizes these data, and to evaluate the effect of selection for RFI on BW and DFI curves. Forty RR models with different-order polynomials of age as fixed and random effects, and with homogeneous or heterogeneous residual variance by month of age, were fitted for both DFI and BW. Based on predicted residual sum of squares (PRESS) and residual diagnostics, the quadratic polynomial RR model was identified to be best, but with heterogeneous residual variance for DFI and homogeneous residual variance for BW. Compared to the simple quadratic and linear regression models for individual pigs, these RR models decreased PRESS by 1% and 2% for DFI and by 42% and 36% for BW on boars and gilts, respectively. Given the same number of random effects as the polynomial RR models, i.e., two for BW and one for DFI, the non-linear Gompertz model predicted better than the polynomial RR models but not as good as higher order polynomial RR models. After five generations of selection for reduced RFI, the LRFI line had a lower population curve for DFI and BW than the CTRL line, especially towards the end of the growth period.

• 산업경영시스템학회지
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• 제37권4호
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• pp.106-115
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• 2014

Until now, because a new product (or facility) launched in market has been retired from one year of age, we can have had ASL by stub-curve method by Iowa curve. Recently, many innovative products with important role in market like display and solar-cell etc. are more durable and, what are better, they have the constant variance in ASL because of their good quality. Of course, there are some ones like smart mobile phone with relatively big dispersion in ASL. Estimating ASL of products like display and solar-cell etc., the new approach is needed. In this paper a new method applied traditional Iowa curve with accelerated reliability test (indoor/outdoor) etc. is proposed.

• 산업경영시스템학회지
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• 제32권1호
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• pp.130-136
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• 2009

Estimation of mortality behavior of a industrial property are useful for calculating depreciation and making management decisions relating to property. The common methods of computing depreciation require an estimation of service life, and some methods may require an estimate of life expectancy. Estimation of service life and life expectancy can be computed from a smoothed and extended life table of original life tables developed through life analysis techniques. Several actuarial techniques are available to construct a life table for depreciation application. Of these methods, the graphic approach and graduation by mathematical formula are the most widely used in the field of depreciation. A commonly used technique of smoothing and of extending the life table is to fit a lows type survivor curves to the observed retirement rate by the least square method. In this paper, estimates of depreciation rate based on directly observed data of the domestic petrochemical equipments are presented.

• Tribology and Lubricants
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• 제17권5호
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• pp.386-390
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• 2001

Monolayers such as self-assembled monolayer (SAM) have received considerable attention to reduce stiction and friction in micro-devices and microelectromechanical systems (MEMS). Various organic molecular films were investigated to obtain better understanding of their tribological behaviors and adhesion property. The organic molecular films studied in this work are: epoxysilane SAMs, octadecyltricholosilane (OST), multi-layers composed of epoxysilane SAMs, poly[styrene-b-(ethylene-co-butylene)-b-styrene](SEBS) and compound of epoxy resin and poly (paraphenylene)(EP/PPP). The pull-off forces of these films were also obtained from force-distance curves measured in static mode of operation of atomic force microscope(AFM). Tribological tests were conducted with a ball-on-flat reciprocating friction tester. The OST showed the lowest pull-off force, indicating its low adhesion property. It was revealed that, the OST, EP/PPP and the multi-layer of epoxysilane SAMs, SEBS and EP/PPP exhibited good tribological properties at the lower load (0.3 N) whereas the OST showed best performance at the higher load (1.8 N).