• Bulletin of the Korean Mathematical Society
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• v.36 no.2
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• pp.287-303
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• 1999

The general solution of the functional equation f1(pr, qs) + f2(ps, qr) = g(p,q) + h(r,s) for p, q, r, s $\in$] 0, 1[will be investigated without any regularity assumptions on the unknown functions f1, f2, g, h:]0.1[->R.

• Journal of Microbiology and Biotechnology
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• v.27 no.12
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• pp.2104-2111
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• 2017

A new series comprising phenylacetyl-homoserine lactones (HSLs), caffeoyl-HSL and feruloyl-HSL, was biologically synthesized using an artificial de novo biosynthetic pathway. We developed an Escherichia coli system containing artificial biosynthetic pathways that yield phenylacetyl-HSLs from simple carbon sources. These artificial biosynthetic pathways contained the LuxI-type synthase gene (rpaI) in addition to caffeoyl-CoA and feruloyl-CoA biosynthetic genes, respectively. Finally, the yields for caffeoyl-HSL and feruloyl-HSL were $97.1{\pm}10.3$ and $65.2{\pm}5.7mg/l$, respectively, by tyrosine-overproducing E. coli with a $\text\tiny{L}$-methionine feeding strategy. In a quorum sensing (QS) competition assay, feruloyl-HSL and p-coumaroyl-HSL antagonized the QS receptor TraR in Agrobacterium tumefaciens NT1, whereas caffeoyl-HSL did not.

• Journal of Microbiology and Biotechnology
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• v.18 no.9
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• pp.1518-1521
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• 2008

Bacteria sense their population density and coordinate the expression of target genes, including virulence factors in Gram-negative bacteria, by the N-acylhomoserine lactones (AHLs)-dependent quorum sensing (QS) mechanism. In contrast, several soil bacteria are able to interfere with QS by enzymatic degradation of AHLs, referred to as quorum quenching. A potent AHL-degrading enzyme, AiiA, from Bacillus thuringiensis has been reported to effectively attenuate the virulence of bacteria by quorum quenching. However, little is known about the role of AiiA in B. thuringiensis itself. In the present study, an aiiA-defective mutant was generated to investigate the role of AHA in rhizosphere competence in the root system of pepper. The aiiA mutant showed no detectable AHL￢-egrading activity and was less effective for suppression of soft-rot symptom caused by Erwinia carotovora on the potato slice. On the pepper root, the survival rate of the aiiA mutant significantly decreased over time compared with that of wild type. Interestingly, viable cell count analysis revealed that the bacterial number and composition of E. carotovora were not different between treatments of wild type and the aiiA mutant. These results provide evidence that AHA can play an important role in rhizosphere competentce of B. thuringiensis and bacterial quorum quenching to Gram-negative bacteria without changing bacterial number or composition.

• Bulletin of the Korean Mathematical Society
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• v.54 no.6
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• pp.2165-2182
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• 2017

Let G be a group and $\mathbb{C}$ the field of complex numbers. Suppose ${\sigma}:G{\rightarrow}G$ is an endomorphism satisfying ${{\sigma}}({{\sigma}}(x))=x$ for all x in G. In this paper, we first determine the central solution, f : G or $G{\times}G{\rightarrow}\mathbb{C}$, of the functional equation $f(xy)+f({\sigma}(y)x)=2f(x)+2f(y)$ for all $x,y{\in}G$, which is a variant of the quadratic functional equation. Using the central solution of this functional equation, we determine the general solution of the functional equation f(pr, qs) + f(sp, rq) = 2f(p, q) + 2f(r, s) for all $p,q,r,s{\in}G$, which is a variant of the equation f(pr, qs) + f(ps, qr) = 2f(p, q) + 2f(r, s) studied by Chung, Kannappan, Ng and Sahoo in [3] (see also [16]). Finally, we determine the solutions of this equation on the free groups generated by one element, the cyclic groups of order m, the symmetric groups of order m, and the dihedral groups of order 2m for $m{\geq}2$.

• Journal of Chest Surgery
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• v.20 no.4
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• pp.688-694
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• 1987

At the Dept. of Thoracic and Cardiovascular Surgery of Pusan National University Hospital, postoperative cardiac catheterizations were performed in 12 patients of ventricular septal defect with severe pulmonary hypertension [Pp/Ps>0.75], who were operated during the period from July 1981 to Dec. 1986. The mean age of the patients preoperatively was 12.4 [range: 4-18] year-old and the mean follow-up duration was 25.8 [range: 8-53] month per patient. In comparison with the preoperative data, the systolic pulmonary artery pressure [SPAP] was decreased from 103.6*18.4 to 70.4*35.9 mmHg [p<0.01] and the Pp/Ps was decreased from 0.89*0.10 to 0.58*0.27 [p<0.01]. But the Rp/Rs and Rp were not meaningfully changed, from 0.31*0.16 and 7.6*0.4 unit to 0.41*0.32 and 8.0*6.6 unit, respectively. The preoperative Qp/Qs was bellow 2.0[mean: 1.6] in 3 out of 4 cases whose postoperative Rp/Rs and Rp were above 0.75 and 15 unit, respectively. On the contrary, the preoperative Qp/Qs was above 2.0 [mean: 3.5] in all of the 8 cases, whose postoperative Rp/Rs and Rp were below 0.50 and 10 unit, respectively.

• Magazine of the Korean Society of Agricultural Engineers
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• v.38 no.1
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• pp.90-97
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• 1996

In Korea, total sediment discharge of a river has been estimated simply by using certain sediment transport formulas including, among others, Einstein's formula. Those formular, however, are known not to be reliable enough for the result calculated by them to be used directly to river planning and management. Therefore, the study used the Modified Einstein Procedure to the estimation of total sediment discharge, because this method is reliable estimated by measurement. Here, measurement of sediment discharge used depth integrating method. The major results obtained from the study for estimation by depth integrating method of sediment discharge in Naeseong stream are as follow; 1 The sedeiment characteristics of Naeseong stream are; The distribution of sediment grain size shows that silt and clay are 55% and sand is 45%. and the bed load sediment grain size is constituted that sand contained with the grain size from O.062mm to 2.0mm is 80% 2. The sediment rating formulas derived from the regression analysis between the sediment discharge and flow discharge are; Seogpo-Gyo : Qs=$0.017 \times 10^{-4} Q^{2.352}$, where discharge is l0cms $0.074 \times 10^{-4} Q^{2.066}$, where discharge is l0cms

• Applied Science and Convergence Technology
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• v.25 no.4
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• pp.81-84
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• 2016

InP/InGaP quantum structures (QSs) grown on GaAs substrates by a migration-enhanced molecular beam epitaxy method were studied as a function of growth temperature (T) using photoluminescence (PL) and emission-wavelength-dependent time-resolved PL (TRPL). The growth T were varied from $440^{\circ}C$ to $520^{\circ}C$ for the formation of InP/InGaP QSs. As growth T increases from $440^{\circ}C$ to $520^{\circ}C$, the PL peak position is blue-shifted, the PL intensity increases except for the sample grown at $520^{\circ}C$, and the PL decay becomes fast at 10 K. Emission-wavelength-dependent TRPL results of all QS samples show that the decay times at 10 K are slightly changed, exhibiting the longest time around at the PL peak, while at high T, the decay times increase rapidly with increasing wavelength, indicating carrier relaxation from smaller QSs to larger QSs via wetting layer/barrier. InP/InGaP QS sample grown at $460^{\circ}C$ shows the strongest PL intensity at 300 K and the longest decay time at 10 K, signifying the optimum growth T of $460^{\circ}C$.

• Applied Science and Convergence Technology
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• v.24 no.3
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• pp.67-71
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• 2015

InP/InGaP quantum structures (QSs) were grown on GaAs (001) substrates by a migration-enhanced molecular beam epitaxy method. Temperature-dependent photoluminescence (PL) and emission wavelength-dependent time-resolved PL (TRPL) were performed to investigate the optical properties of InP/InGaP QSs as a function of migration enhanced epitaxy (MEE) growth cycles from 2 to 8. One cycle for the growth of InP QS consists of 2-s In and 2-s P supply with an interruption time of 10 s after each source supply. As the MEE growth cycle increases from 2 to 8, the PL peak is redshifted and exhibited different (larger, comparable, or smaller) bandgap shrinkages with increasing temperature compared to that of bulk InP. The PL decay becomes faster with increasing MEE cycles while the PL decay time increases with increasing emission wavelength. These PL and TRPL results are attributed to the different QS density and size/shape caused by the MEE repetition cycles. Therefore, the size and density of InP QSs can be controlled by changing the MEE growth cycles.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.34-37
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• 2003

This paper proposes a BPM(Business Process Management) system framework for the NPD(New Product Development) of automotive suppliers. Recently many enterprises change their organization from function-oriented to process-oriented through BPR (Business Process Reengineering). Especially, based on quality systems like QS9000, it is required to documented business processes and continuously improve these processes for customer satisfaction. NPD, the most significant function for industrial competition, is reinforced by the best practices business process to satisfy the requirements of quality systems. The main objective of the paper is the development of the information system that supports the best practices process management. For this, first, we define the requirements of BPM system for NPD based on the viewpoint analysis, and then propose a DES (Design Execution System) framework based on dynamic workflow engine. The DES is addressed in the characteristics of a NPD business process, integrated project management, and process execution. A prototype DES system has been developed in the web environment. Its validity is demonstrated by applying it to an automotive supplier.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.36S no.11
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• pp.1-8
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• 1999

In this paper, new polyphase sequences and a sequence generation method are suggested. These sequences are found to have good correlation properties. Since the suggested generation method consists only of integer sums and modular techniques, sequence generation is also easy. The performance of the sequences is investigated when used in QS-CDMA systems under frequency selective, time nonselective, slow Nakagami fading channel with additive white Gaussian noise.