• Korean Journal of Materials Research
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• v.25 no.12
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• pp.713-718
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• 2015

A new method is proposed for the calculation of the unrelaxed surface energy of spinel ferrite. The surface energy calculation consists of (1) setting the central and computational domains in the semi-infinite real lattice, having a specific surface, and having an infinite real lattice; (2) calculation of the lattice energies produced by the associated portion of each ion in the relative domain; and (3) dividing the difference between the semi-infinite lattice energy and the infinite lattice energy on the exposed surface area in the central domain. The surface energy was found to converge with a slight expansion of the domain in the real lattice. This method is superior to any other so far reported due to its simple concept and reduced computing burden. The unrelaxed surface energies of the (100), (110), and (111) of $ZnFe_2O_4$ and $Fe_3O_4$ were evaluated by using in the semi-infinite real lattices containing only one surface. For the normal spinel $ZnFe_2O_4$, the(100), which consisted of tetrahedral coordinated $Zn^{2+}$ was electrostatically the most stable surface. But, for the inverses pinel $Fe_3O_4$, the(111), which consisted of tetrahedral coordinated $Fe^{3+}$ and octahedral coordinated $Fe^{2+}$ was electrostatically the most stable surface.

• Journal of the Korean Institute of Telematics and Electronics
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• v.25 no.2
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• pp.119-124
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• 1988

Real-time adaptive lattice predictor was implemented on the TMS32020 DSP chip for digital signal processing. The implemented system was composed of Input-Output units and centrla processing-control unit and its supporting assembly soft ware. The performance of hardware realization was verified by comparing input signal and one-step prediction signal which are calcualted by the real-time adaptive lattice predictor. As a result, for 4 stage lattice structure, the maximum running frequency was obtained as 6.41 KHz in this experiment.

• Bulletin of the Korean Chemical Society
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• v.18 no.9
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• pp.965-972
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• 1997

An approximate molecular theory of classical fluids based on the nonrandom lattice statistical-mechanical theory is presented. To obtain configurational Helmholtz free energy and equation of state (EOS), the lattice-hole theory of the Guggenheim combinatorics is approximated by introducing the nonrandom two-fluid theory. The approximate nature in the derivation makes the model possible to unify the classical lattice-hole theory and to describe correctly the configurational properties of real fluids including macromolecules. The theory requires only two molecular parameters for a pure fluid. Results obtained to date have demonstrated that the model correlates quantitatively the first- and second-order thermodynamic properties of real fluids. The basic simplicity of the model can readily be generalized to multicomponent systems. The model is especially relevant to (multi) phase equilibria of systems containing molecularly complex species.

• Journal of applied mathematics & informatics
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• v.20 no.1_2
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• pp.409-420
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• 2006

In this paper we consider the set of all n + 1-tuples of real numbers, not necessarily all distinct, in the decreasing order from the unit interval under the usual ordering of real numbers, always including 1. Such n + 1-tuples inherently arise as the membership values of fuzzy subsets and are called keychains. An natural equivalence relation is introduced on this set and the equivalence classes of keychains are studied here. The number of such keychains is finite and the set of all keychains is a lattice under the coordinate-wise ordering. Thus keychains are subchains of a finite chain of real numbers in the unit interval. We study some of their properties and give some applications to counting fuzzy subsets of finite sets.

• Journal of Korean Society for Atmospheric Environment
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• v.2 no.3
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• pp.52-56
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• 1986

In this paper a adaptive LMS(least mean-square) lattice predictor, which is composed of the adaptive lattice algorithm and LMS algorithm by Widrow-Hopf, is used to predict the future air pollution of the extraordinary levels in the environmental system. This prediction algorithm is applied to the one-step forward prediction of atmospheric CO concentration by using real observed data. Computer simulation proves that the power in the forward error sequences decreases as the number of stages in the lattice is increased.

• Journal of the Korean Ceramic Society
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• v.31 no.4
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• pp.420-426
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• 1994

A new method is proposed for the oxide lattice energy calculation. It is consisted of (1) setting a central and a computation domains in a real lattice, (2) calculation of inter-ionic potential producted by the associated portion of each ion to the relative domain, and (3) summing up the potential energies. Even with a slight expansion of the domain, the lattice energy converges to the published data. The method is superior than any other reported due to the simple and clear concept and the reduced computing.

• Proceedings of the Korea Technology Innovation Society Conference
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• 2002.05b
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• pp.181-198
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• 2002

This article describes a methodology for evaluating huge aerospace R&D investments using the real options pricing method. Option pricing has been proposed as a useful approach for modeling investment in R&D. Two important features of R&D investments are that an R&D project takes time to complete and that the outcome of R&D investments is highly uncertain. This makes the analysis of R&D investments difficult. Traditional tools for project evaluation, like IRR or the NPV, are inadequate for coping with the high uncertainty. Hence, In this article I propose a log-transformed binomal lattice method, and it will show that option pricing might be an adequate framework for evaluating such types of aerospace investments.

• Bulletin of the Korean Chemical Society
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• v.17 no.9
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• pp.808-813
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• 1996

To explore protein folding mechanism, we simulated a folding pathway in a simplified 3×3×3 cubic lattice. In the lattice folding Monte Carlo simulations, each of the 28 possible native packing pairs that exist in the native conformation was used as a conformational restraint. The native packing restraints in the lattice model could be considered as a disulfide linkage restraint in a real protein. The results suggest that proteins denatured with a small disulfide loop can, but not always, fold faster than proteins without any disulfide linkage and than proteins with a larger disulfide loop. The results also suggest that there is a rough correlation between loop size of the native packing restraint and folding time. That is, the order of native residue-residue packing interaction in protein folding is likely dependent on the residue-residue distance in primary sequence. The strength of monomer-monomer pairwise interaction is not important in the determination of the packing order in lattice folding. From the folding simulations of five strong folding lattice sequences, it was also found that the context encoded in the primary sequence, which we do not yet clearly understand, plays more crucial role in the determination of detailed folding kinetics. Our restrained lattice model approach would provide a useful strategy to the future protein folding experiments by suggesting a protein engineering for the fast or slow folding research.

• Journal of Korean Institute of Industrial Engineers
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• v.29 no.2
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• pp.126-134
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• 2003

Among a variety of models proposed by so far to calculate the real options value when the investment decision about the underlying project may be delayed, the Black-Scholes and the binomial lattice models have been widely used and discussed by academics and practitioners. However these two models do not provide us with intuition into how it is constructed and what it does really mean. In this paper, we will therefore explore its components and practically more intuitive meaning. With the components explored, we developed the mathematical model to calculate the real options value and thus strategic net present value, based on the opportunity cost concept, for which the investment decision about the underlying project is postponed by one year. We will finally present a short illustrative example for readers better understanding on the model proposed in the paper.

• Journal of Korean Institute of Industrial Engineers
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• v.32 no.3
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• pp.180-190
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• 2006

We evaluate the economic value and the optimal investment timing of IMT-2000 in Korea, in the perspective of a service provider who owns the business license for IMT-2000, by using the real options analysis. The result clearly shows the project value with options is positive and delaying the investment is more favorable to the provider. Binomial lattice approach, in which we try to describe American call option and sequential compound option, and sensitivity analysis present the optimal decisions according to future states and enable the management to make decision strategically and proactively.