• BMB Reports
• /
• v.30 no.2
• /
• pp.113-118
• /
• 1997

Aspartase from Hafnia alvei was inactivated by N-ethylmaleimide (NEM) and 5,5' -Dithiobis-(2-znitrobenzoic acid) (DTNB) following pseudo-first order kinetics. Their apparent reaction orders were 0.83 and 0.50 for NEM and DTNB modifications, respectively, indicating that inactivation was due to a sulfhydryl group in the active site of aspartase and participation of the sulfhydryl group in an essential step in the catalytic reaction. When aspartase was modified by DTNB, the enzyme activity was restored by dithiothreitol treatment, indicating that cysteine residuetsl islarel possibly at or near the active site. The pH-dependence of the inactivation rate by NEM suggested that an amino acid residue having pK value of 8.3 was involved in the inactivation. When aspartase was incubated with NEM and L-aspartate together, L-aspartate markedly protected the enzyme from inactivation by NEM, but the other reagents used did not.

• The Bulletin of The Korean Astronomical Society
• /
• v.43 no.1
• /
• pp.49.5-50
• /
• 2018

Korean chronicles have a large amount of observational records over two thousand years. Many historical astronomical records are useful in modern times. In this study, we examined solar eclipses in Goguryeo-bongi(高句麗本紀) by using the modified(newest) nutation value and reviewed the observation area through eclipsing map. There are 11 solar eclipse records in the book. We calculated intersectional visible area with 0.6 eclipsing magnitude using the records of AD116, 124, 149, 158 and 219 and found the observational area of $N40-43^{\circ}$ and $E123-127^{\circ}$, which corresponds to the Liaodong(遼東). We also examined historical Chinese solar eclipse records and compared them with Korean eclipses.

• Journal of applied mathematics & informatics
• /
• v.14 no.1_2
• /
• pp.97-113
• /
• 2004

In this paper we shall study moving boundary problems, and we introduce an approach for solving a wide range of them by using calculus of variations and optimization. First, we transform the problem equivalently into an optimal control problem by defining an objective function and artificial control functions. By using measure theory, the new problem is modified into one consisting of the minimization of a linear functional over a set of Radon measures; then we obtain an optimal measure which is then approximated by a finite combination of atomic measures and the problem converted to an infinite-dimensional linear programming. We approximate the infinite linear programming to a finite-dimensional linear programming. Then by using the solution of the latter problem we obtain an approximate solution for moving boundary function on specific time. Furthermore, we show the path of moving boundary from initial state to final state.

• Journal of applied mathematics & informatics
• /
• v.29 no.3_4
• /
• pp.937-948
• /
• 2011

The method of Asymptotic Inner Boundary Condition for Singularly Perturbed Two-Point Boundary value Problems is presented. By using a terminal point, the original second order problem is divided in to two problems namely inner region and outer region problems. The original problem is replaced by an asymptotically equivalent first order problem and using the stretching transformation, the asymptotic inner condition in implicit form at the terminal point is determined from the reduced equation of the original second order problem. The modified inner region problem, using the transformation with implicit boundary conditions is solved and produces a condition for the outer region problem. We used Chawla's fourth order method to solve both the inner and outer region problems. The proposed method is iterative on the terminal point. Some numerical examples are solved to demonstrate the applicability of the method.

• Journal of Communications and Networks
• /
• v.17 no.3
• /
• pp.241-246
• /
• 2015

In this paper, we consider a relaying system which employs a single relay in a wireless network with distributed sources and destinations. Here, all source, destination, and relay nodes are equipped with multiple antennas. For amplify-and-forward relay systems, we confirm the achievable sum rate through a joint multiple source precoders and a single relay filter design. To this end, we propose a new linear processing scheme in terms of maximizing the sum rate performance by applying a blockwise relaying method combined with geometric programming techniques. By allowing the global channel knowledge at the source nodes, we show that this joint design problem is formulated as a standard geometric program, which can guarantees a global optimal value under the modified sum rate criterion. Simulation results show that the proposed blockwise relaying scheme with the joint power allocation method provides substantial sum rate gain compared to the conventional schemes.

• Nuclear Engineering and Technology
• /
• v.47 no.1
• /
• pp.126-134
• /
• 2015

A simple Couette flow velocity profile with an appropriate correlation for the free terminal rise velocity of a single bubble in a quiescent liquid can produce reliable results for the trajectories of small spherical air bubbles in a low-viscosity liquid (water) provided the liquid remains under uniform shear flow. Comparison of the model adopted in this paper with published results has been accomplished. Based on this study it has also been found that the lift coefficient in water is higher than its typical value in a high-viscosity liquid and therefore a modified correlation for the lift coefficient in a uniform shear flow of water within the regime of the $E\ddot{o}tv\ddot{o}s$ number $0.305{\leq}Eo{\leq}1.22$ is also presented.

• Proceedings of the Korean Society of Broadcast Engineers Conference
• /
• 1999.06a
• /
• pp.97.1-102
• /
• 1999

This paper porposes and efficient coding scheme for remote medical communication systems, or“telemedicine systems”. These systems require a technique which is able to transfer large volume of data such as X-ray images effectively. We have already developed a hierarchical image coding and transmission scheme (HITS), which achieves an efficient transmission of medical images simply[1]. In this paper, a new coding scheme for HITS is proposed, which used hierarchical context modeling for the purpose of improving the coding efficiency. The hierarchical context modeling divides wavelet coefficients into several sets by the value of a correspondent coefficient in their higher class, or“a parent”, optimizes a Golomb-Rice (GR) code parameter in each set, and then encodes the coefficients with the parameter. Computer simulation shows that the proposed scheme is effective with simple implementation. This is due to fact that a wavelet coefficient has dependence on its parent. As a result, high speed data transmission is achieved even if the telemedicine system consists of simple personal computers.

• Journal of the Korean Society of Tobacco Science
• /
• v.17 no.1
• /
• pp.57-61
• /
• 1995

Black shank(Phytophthora parasitira roar. nicotianae) resistant burley tobacco (Nicotiana tabacum L.) germplasms, KB 104 and KB 106, were developed by Korea Ginseng & Tobacco Research Institute. KB 104 was developed from the single cross of Burley 21$\times$Newton 77, using a modified pedigree method. KB 104 was highly resistant to black shank, and its agronomic characteristics and chemical contents were comparable to those of Burley 21, and value per 10a was slightly higher than Burley 21, KB 106 is a maternally derived doubled haploid made by N. africana method from the single cross of Burley 21$\times$ Va 509. KB 106 was also highly resistant to black shank, had two more harvestable leaves per plant and flowered three days later than Burley 21 did. Total alkaloid and nicotine contents of KB 106 were significantly lower than those of Burley 21. But its nornicotine content was higher than Burley 21 5. Key wads : Burley tobacco germplasm, Black shank resistance.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2009.10a
• /
• pp.755-757
• /
• 2009

Since the research of advanced terrestrial digital multimedia broadcasting system is still in progress, and in our previous paper, in which we introduced how to combine one conventional transmitted symbol with two additional bits to form a new symbol transmission, the bit error performance of LP bits is not realizable, because even we implemented the turbo code to protect the LP bits transmission, to obtain a certain good bit error probability, the value of $E_b/N_0$ cost highly. In this paper, we modified the composition of low-priority symbol and high-priority symbol, and through the system presented in previous paper we get a better simulation result of the LP symbol transmission.

• Transactions of the Korean Society of Pressure Vessels and Piping
• /
• v.16 no.1
• /
• pp.92-99
• /
• 2020

High-temperature mechanical behaviors of Type 316L stainless steel (SS), which is considered as one of the major structural materials of Generation-IV nuclear reactors, were investigated through the tension and creep tests at elevated temperatures. The tension tests were performed under the strain rate of 6.67×10^-4 (1/s) from room temperature to 650℃, and the creep tests were conducted under different applied stresses at 550℃, 600℃, 650℃, and 700℃. The tensile behavior was investigated, and the modeling equations for tensile strengths and elongation were proposed as a function of temperature. The creep behavior was analyzed in terms of various creep equations: Norton's power law, modified Monkman-Grant relation, damage tolerance factor(λ), and Z-parameter, and the creep constants were proposed. In addition, the tested tensile and creep strengths were compared with those of RCC-MRx. Results showed that creep exponent value decreased from n=13.55 to n=7.58 with increasing temperature, λ = 6.3, and Z-parameter obeyed well a power-law form of Z=5.79E52(σ/E)^9.12. RCC-MRx showed lower creep strength and marginally different in creep strain rate, compared to the tested results. Same creep deformation was operative for dislocation movement regardless of the temperatures.