• Journal of applied mathematics & informatics
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• v.30 no.5_6
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• pp.759-772
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• 2012

In this paper, semi-infinite constrained programming, a class of constrained nonsmooth optimization problems, are transformed into unconstrained nonsmooth convex programs under the help of exact penalty function. The unconstrained objective function which owns the primal-dual gradient structure has connection with $\mathcal{VU}$-space decomposition. Then a $\mathcal{VU}$-space decomposition method can be applied for solving this unconstrained programs. Finally, the superlinear convergence algorithm is proved under certain assumption.

• Proceedings of the KSME Conference
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• 2003.04a
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• pp.491-496
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• 2003

In sensitivity analysis, semi-analytical method(SAM) reveals severe inaccuracy problem when relatively large rigid body motions are identified for individual elements. Recently such errors of SAM resulted by the finite difference scheme have been improved by the separation of rigid body mode. But the eigenvalue should be obtained first before the sensitivity analysis is performed and it takes much time in the case that large system is considered. In the present study, by constructing a reduced one from the original system, iterative method combined with mode decomposition technique is proposed to compute reliable semi-analytical design sensitivities. The sensitivity analysis is performed by the eigenvector acquired from the reduced system. The error of SAM caused by difference scheme is alleviated by Von Neumann series approximation.

• Journal of Environmental Science International
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• v.8 no.3
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• pp.325-330
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• 1999

This study aims to observe the inhibition of methane generation, the decomposition of organic matter, and the trend of outflowing leachate, using the simulated column of the anaerobic sanitary landfill structure of sulfate addition type which is made by adding sulfate to a current anaerobic landfill structure, and the simulated column of semi-aerobic landfill structure in the laboratory which is used in the country like Japan in order to inhibit methane from a landfill site among the gases caused by a global warming these days, and at the same time to promote the decomposition of organic matter, the index of stabilization of landfill site. As a result of this study, it is thought that the ORP(Oxidation Reduction Potential) of the column of semi-aerobic landfill structure gradually represents a weak aerobic condition as time goes by, and that the inside of landfill site is likely to by in progress into anaerobic condition, unless air effectively comes into a semi-aerobic landfill structure in reality as time goes by. In addition, it can be seen that the decomposition of organic matter is promoted according to sulfate reduction in case of $R_1$, a sulfate-added anaerobic sanitary landfill structure, and that the stable decomposition of organic matter in $R_1$ makes a faster progess than $R_2$. Moreover it can be estimated that $R_1$, a sulfate-added anaerobic sanitary landfill structure has an inhibition efficiency of 55% or so, compared with $R_2$, a semi-aerobic landfill structure, in the efficiency of inhibiting methane.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.27 no.4
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• pp.585-592
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• 2003

Among various sensitivity evaluation techniques, semi-analytical method(SAM) is quite popular since this method is more advantageous than analytical method(AM) and global finite difference method(FDM). However, SAM reveals severe inaccuracy problem when relatively large rigid body motions are identified fur individual elements. Such errors result from the numerical differentiation of the pseudo load vector calculated by the finite difference scheme. In the present study, an iterative method combined with mode decomposition technique is proposed to compute reliable semi-analytical design sensitivities. The improvement of design sensitivities corresponding to the rigid body mode is evaluated by exact differentiation of the rigid body modes and the error of SAM caused by numerical difference scheme is alleviated by using a Von Neumann series approximation considering the higher order terms for the sensitivity derivatives.

• Journal of the Chungcheong Mathematical Society
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• v.32 no.4
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• pp.409-420
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• 2019

In this article, we discussed semi-analytical approximated methods for solving mixed Volterra-Fredholm integro-differential equations, namely: Adomian decomposition method and modified Adomian decomposition method. Moreover, we prove the uniqueness results and convergence of the techniques. Finally, an example is included to demonstrate the validity and applicability of the proposed techniques.

• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 2001.05a
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• pp.125-128
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• 2001

• Bulletin of the Korean Mathematical Society
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• v.53 no.2
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• pp.441-460
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• 2016

We introduce the notions of h-v-semi-slant submersions and almost h-v-semi-slant submersions from almost quaternionic Hermitian manifolds onto Riemannian manifolds. We obtain characterizations, investigate the integrability of distributions, the geometry of foliations, and a decomposition theorem. We find a condition for such submersions to be totally geodesic. We also obtain an inequality of a h-v-semi-slant submersion in terms of squared mean curvature, scalar curvature, and h-v-semi-slant angle. Finally, we give examples of such maps.

• Communications of the Korean Mathematical Society
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• v.36 no.1
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• pp.173-187
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• 2021

In this paper, we deal with the notion of a v-semi-slant submersion from an almost Hermitian manifold onto a Riemannian manifold. We investigate the integrability of distributions, the geometry of foliations, and a decomposition theorem. Given such a map with totally umbilical fibers, we have a condition for the fibers of the map to be minimal. We also obtain an inequality of a proper v-semi-slant submersion in terms of squared mean curvature, scalar curvature, and a v-semi-slant angle. Moreover, we give some examples of such maps and some open problems.

• Journal of Korean Society of Water and Wastewater
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• v.24 no.6
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• pp.775-788
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• 2010

The decomposition of 2,4,6-trinitrotoluene (TNT) and the mass balance of nitrogen (N) species as products were investigated in a UV/H2O2system by varying pH, concentrations of $H_2O_2$, and $O_2$. All experiments were conducted in a semi-batch system employing a 50 mL reaction vessel and a coil-type quartz-tube reactor. In contrast with previous studies employing batch mode, TNT decomposition in the semi-batch mode was proportionally enhanced by increasing $H_2O_2$ concentration to 10 mM (0.034%), indicatingthat an inhibitory effect of excess $H_2O_2$on hydroxyl radical (${\cdot}OH$) can be negligible. N compounds are released as $NO_2^-$ in the early stages of the reaction, but $NO_2^-$ is rapidly oxidized to $NO_3^-$ by means of ${\cdot}OH$. $NH_4^+$ was also detected in this study and showed gradually the increase with increasing reaction time. In this study, $NH_4^+$ production can involve the reduction of nitro group of TNT concurrent with the production of $NO_3^-$. Of the N species originating from TNT decomposition, 12 ~ 72% were inorganic forms (i.e. [$NO_3^-$] + [$NO_2^-$] + [$NH_4^+$]). This result suggests that the large remaining N portions indicate that unidentified N compounds can exist.

• 한국데이터정보과학회:학술대회논문집
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• 2003.05a
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• pp.133-133
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• 2003