• Journal of the Korean Mathematical Society
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• v.34 no.3
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• pp.661-672
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• 1997

In this paper we introduce the semidiscrete solution of a single-phase nonlinear Stefan problem We analyze the optimal convergence of the semidiscrete solution in $H^1$ and $H^2$ normed spaces and also we derive the error estimates in $L^2$ normed space.

• Journal of the Korean Mathematical Society
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• v.34 no.3
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• pp.515-531
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• 1997

In this paper, finite difference method is applied to approximate the generalized solutions of Sobolev equations. Using the Steklov mollifier and Bramble-Hilbert Lemma, a priori error estimates in discrete $L^2$ as well as in discrete $H^1$ norms are derived frist for the semidiscrete methods. For the fully discrete schemes, both backward Euler and Crank-Nicolson methods are discussed and related error analyses are also presented.

• Journal of applied mathematics & informatics
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• v.12 no.1_2
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• pp.119-127
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• 2003

The purpose of this paper is to study the necessary and sufficient conditions for the sequences of Ishikawa iterative sequences with mixed errors of asymptotically quasi-nonexpansive type mappings in Banach spaces to converge to a fixed point in Banach spaces. The results presented in this paper extend and improve the corresponding results of［l-4, 7-9].

• The Mathematical Education
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• v.14 no.1
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• pp.19-21
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• 1975

약 위상과 강위상이 주어진 선형공간 E에서 수열의 약수렴과 강수렴에 관한 성질을 보조정리로하여 두 Banach공간 E와 F사이에 정의된 연속작용소 공간 L(E.F)에서 작용소열 { $T_{n}$ }이 T에 강수렴하기 위한 필요충분조건은 F가 Hilbert 공간일때는 { $T_{n}$ }이 T에 약수렴함과 동시에 실수열 (equation omitted)$T_{\chi}$ $n^{\chi}$(equation omitted)가 실수 (equation omitted)T$\chi$(equation omitted)에 수렴할 때이다.

• Journal of the Korean Society of Industry Convergence
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• v.1 no.1
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• pp.43-49
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• 1998

The SS-phpm 4HCl(N,N'-bis-[2(S)-pyrrolidinylmethyl]phenylene-l,2-diamine-4-Hydrochloride) ligand having stereospecificity has been prepared and reacted with trans-[$Co(pyridine)_4Cl_2]$Cl. The resultants are purple crystals, which are identified to be ${\Delta}$-cis-${\beta}$-[$Co(SS-phpm)Cl_2$]Cl by elemental analysis and UV/Vis- and CD-absorption spectra, The conformation of SS-phpm in ${\Delta}$-cis-${\beta}$ complex is ${\delta}$ ${\varepsilon}$ ${\lambda}$ (SSSS) for each of the five-membered chelated ring. Futhermore, according to orientation of secondary amine, total strain energy on each isomers was calculated by molecular mechanics(MM) to verify structural characterization and spectral data. As the result, the most stabilized isomer was ${\Delta}$-cis-${\beta}$(SSSS). The value of total strain energy(U) of ${\Delta}$-cis-${\beta}$(SSSS) isomer was 63.21 kcal/mol, respectively.

• Interaction and multiscale mechanics
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• v.1 no.1
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• pp.33-51
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• 2008

This paper investigates the modelling of coupled soil-structure interaction problems by domain decomposition techniques. It is assumed that the soil-structure system is physically partitioned into soil and structure subdomains, which are independently modelled. Coupling of the separately modelled partitioned subdomains is undertaken with various algorithms based on the sequential iterative Dirichlet-Neumann sub-structuring method, which ensures compatibility and equilibrium at the interface boundaries of the subdomains. A number of mathematical and computational characteristics of the coupling algorithms, including the convergence conditions and choice of algorithmic parameters leading to enhanced convergence of the iterative method, are discussed. Based on the presented coupling algorithms a simulation environment, utilizing discipline-oriented solvers for nonlinear structural and geotechnical analysis, is developed which is used here to demonstrate the performance characteristics and benefits of various algorithms. Finally, the developed tool is used in a case study involving nonlinear soil-structure interaction analysis between a plane frame and soil subjected to ground excavation. This study highlights the relative performance of the various considered coupling algorithms in modelling real soil-structure interaction problems, in which nonlinearity arises in both the structure and the soil, and leads to important conclusions regarding their adequacy for such problems as well as the prospects for further enhancements.

• Structural Engineering and Mechanics
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• v.76 no.4
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• pp.435-449
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• 2020

This work presents the formulation of the isogeometric collocation method to solve the strong form equation of a unified and integrated approach of Reissner Mindlin plate theory (UI-RM). In this plate theory model, the total displacement is expressed in terms of bending and shear displacements. Rotations, curvatures, and shear strains are represented as the first, the second, and the third derivatives of the bending displacement, respectively. The proposed formulation is free from shear locking in the Kirchhoff limit and is equally applicable to thin and thick plates. The displacement field is approximated using the B-splines functions, and the strong form equation of the fourth-order is solved using the collocation approach. The convergence properties and accuracy are demonstrated with square plate problems of thin and thick plates with different boundary conditions. Two approaches are used for convergence tests, e.g., increasing the polynomial degree (NELT = 1×1 with p = 4, 5, 6, 7) and increasing the number of element (NELT = 1×1, 2×2, 3×3, 4×4 with p = 4) with the number of control variable (NCV) is used as a comparable equivalent variable. Compared with DKMQ element of a 64×64 mesh as the reference for all L/h, the problem analysis with isogeometric collocation on UI-RM plate theory exhibits satisfying results.

• Journal of Positioning, Navigation, and Timing
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• v.11 no.4
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• pp.251-261
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• 2022

The Centimeter Level Augmentation Service (CLAS) is the Precise Point Positioning (PPP) - Real Time Kinematic (RTK) correction service utilizing the Quasi-Zenith Satellite System (QZSS) L6 (1278.65 MHz) signal to broadcast the Global Navigation Satellite System (GNSS) error corrections. Compact State-Space Representation (CSSR) corrections for mitigating GNSS measurement error sources such as satellite orbit, clock, code and phase biases, tropospheric error, ionospheric error are estimated from the ground segment of QZSS CLAS using the code and carrier-phase measurements collected in the Japan's GNSS Earth Observation Network (GEONET). Since the CLAS service begun on November 1, 2018, users with dedicated receivers can perform cm-level precise positioning using CSSR corrections. In this paper, CLAS-based VRS-RTK performance evaluation was performed using Global Positioning System (GPS) observables collected from the refence station, TSK2, located in Japan. As a result of performing GPS-only RTK positioning using the open-source software CLASLIB and RTKLIB, it took about 15 minutes to resolve the carrier-phase ambiguities, and the RTK fix rate was only about 41%. Also, the Root Mean Squares (RMS) values of position errors (fixed only) are about 4cm horizontally and 7 cm vertically.

• Journal of Acupuncture Research
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• v.34 no.2
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• pp.83-91
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• 2017

Objectives : Alpiniae oxyphyllae Fructus (AOF) is an herbal medicine, which has been used for the treatment of fatigue, chills, and poor physical conditions. The objective of this study was to investigate the anti-inflammatory and anti-oxidative effects of AOF hot aqueous extract. Methods : The cytotoxicity of AOF extract was evaluated using the MTT assay. Nitric oxide (NO) production was measured by the Griess reaction. Prostaglandin $E_2$ ($PGE_2$) production was measured by a commercial competitive enzyme immunoassay. Cytokine production (IL-1tion co6, and TNF- F- was measured by ELISA. The anti-oxidative effect of AOF extracts was measured by the DPPH method. Polyphenol and flavonoid contents were measured by Folin-Ciocalteu's phenol reagent and aluminum chloride, respectively. Results : AOF hot aqueous extract did not show toxicity at doses of 25, 50, 100, and $200{\mu}g/mL$. AOF extract significantly inhibited NO production at doses of 100 and $200{\mu}g/mL.PGE_2$ production was inhibited by AOF extract treatment at doses of 100 and $200{\mu}g/mL$. AOF extracts reduced IL-6 production in a dose-dependent manner. IL-1ent maTNF- F- 1ent mannerd IL-6 production in uction at doses of 100 and ${\mu}g/mL$. The DPPH free radical scavenging capability was above 50% at $200{\mu}g/mL$. Conclusion : This study suggests that AOF hot aqueous extract may exert anti-inflammatory and anti-oxidative effects in a dose-dependent manner. Further studies are required for validating the safety and efficacy of AOF.

• Journal of Microbiology and Biotechnology
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• v.29 no.7
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• pp.1165-1176
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• 2019

Botulinum neurotoxins (BoNTs), produced by Clostridium botulinum, are the most toxic substances known. However, the number of currently approved medical countermeasures for these toxins is very limited. Therefore, studies on therapeutic antitoxins are essential to prepare for toxin-related emergencies. Currently, more than 10,000 Halla horses, a crossbreed between the native Jeju and Thoroughbred horses, are being raised in Jeju Island of Korea. They can be used for equine antitoxin experiments and production of hyperimmune serum against BoNT/A1. Instead of the inactivated BoNT/A1 toxoid, Halla horse was immunized with the receptor-binding domain present in the C-terminus of heavy chain of BoNT/A1 (BoNT/A1-HCR) expressed in Escherichia coli. The anti-BoNT/A1-HCR antibody titer increased rapidly by week 4, and this level was maintained for several weeks after boosting immunization. Notably, $20{\mu}l$ of the week-24 BoNT/A1-HCR(-immunized) equine serum showed an in vitro neutralizing activity of over 8 international units (IU) of a reference equine antitoxin. Furthermore, $20{\mu}l$ of equine serum and $100{\mu}g$ of purified equine $F(ab^{\prime})_2$ showed 100% neutralization of 10,000 $LD_{50}$ in vivo. The results of this study shall contribute towards optimizing antitoxin production for BoNT/A1, which is essential for emergency preparedness and response.