• Journal of the Korean Society for Industrial and Applied Mathematics
• /
• v.3 no.1
• /
• pp.71-79
• /
• 1999

We consider multi-step quasi-Newton methods for unconstrained optimization. These methods were introduced by Ford and Moghrabi [1, 2], who showed how interpolating curves could be used to derive a generalization of the Secant Equation (the relation normally employed in the construction of quasi-Newton methods). One of the most successful of these multi-step methods makes use of the current approximation to the Hessian to determine the parameterization of the interpolating curve in the variable-space and, hence, the generalized updating formula. In this paper, we investigate new parameterization techniques to the approximate Hessian, in an attempt to determine a better Hessian approximation at each iteration and, thus, improve the numerical performance of such algorithms.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.27 no.5
• /
• pp.789-797
• /
• 2003

In the procedure of the hydraulic control system design, a linearized approximate equation described by the first order terms of Taylor series has been widely used. Such a linearized equation is effective just near the operating point, However, pressure and flowrate in actual hydraulic systems are usually not confined near an operating point. This study suggests a new linearized flow equation for a servovalve as a modified form of the conventional linearized flow equation. Subsequently, a procedure to determine effective operating point for the new linearized equation is proposed. From the evaluations of time responses and frequency responses obtained from simulations for a hydraulic control system, the effectiveness of the new linearized equation and the procedure to determine effective operating point is confirmed.

• Journal of Society of Preventive Korean Medicine
• /
• v.10 no.2
• /
• pp.131-145
• /
• 2006

Perilla frutescens is known as the herb helps digestion, tonifies stomachache, and decreases fever in oriental medicine. And it is reported it possess the anti-pyretic effect, anti-inflammatory effect, anti-allergy effect, anti-tumor effect etc. The components isolated from this herb consist of perilla aldehyde, d-limonene, ${\alpha}-pinene$, cyanin, linoleic acid, palmitic acid, menthol, rosmarinic acid and luteolin etc. But there is no effective tools to determine the quality of this herb. In this study, we aimed to analyze the changes of liquid chromatogram pattern, one of major standardization method, to determine the quality of Perilla frutescens.

• Journal of Society of Preventive Korean Medicine
• /
• v.20 no.3
• /
• pp.21-29
• /
• 2016

Objectives : The purpose of this study is to determine the Korean medicine brand personality awareness of university students and to determine how the Korean medicine brand personality affects the perceived value. Methods : The data for this study were collected through a self-administered survey to 173 subject from students enrolled in the University in B city. Frequency analysis, factor analysis, t-test, ANOVA, multiple regression analysis were used for the statistical analysis. Results : The result of factor analysis, seven factors were extracted. That was refinement, pleasure, trust, warmhearted, capacity, handsomeness, individuality. Overall, capacity, trust, warmhearted, handsomeness scores of Korean medicine brand personality score was higher than individuality, pleasure, refinement. Especially warmhearted, capacity affects the perceived value. Conclusions : Seven Korean medicine brand personality factors were extracted. Warmhearted, capacity affects the perceived value. It is necessary to develop the Korean medical management strategy and Korean medical policy.

• Journal of Korean Society for Quality Management
• /
• v.28 no.1
• /
• pp.210-219
• /
• 2000

When an electronic control system has been used for long time, the electronic control system becomes obsolete and no longer In production. In this case, the existing control system should replace by new system due to shortage of spare modules. However, if the proper number of spare modules are stocked, it may be possible and more economical than to replace by new system to extend the usage period of the existing control system. In this case, it is an important problem to determine the proper number of spare modules. In this paper, a method to determine the proper number of spare modules is presented with an application example.

• Journal of Korean Society for Quality Management
• /
• v.20 no.1
• /
• pp.158-167
• /
• 1992

This paper represents the new techniques for optimal sampling plans of reliability applying the mathematical complex number(real and imaginary number) in the complex system of reliability. The research formulation represent a mathematical model Which preserves all essential aspects of the main and auxiliary factors of the research objectives. It is important to formule the problem in good agreement with the objective of the research considering the main and auxilary factors which affect the system performance. This model was repeatedly tested to determine the required statistical chatacteristics which in themselves determine the actual and standard distributions. The evaluation programs and techniques are developed for establishing criteria for sampling plans of reliability effectiveness, and the evaluation of system performance was based on the complex stochastic process(derived by the Runge-Kutta method. by kolmogorv's criterion and the transform of a solution to a Sturon-Liouville equation.) The special structure of this mathematical model is exploited to develop the optimal sampling plans of reliability in the complex system.

• Journal of Preventive Medicine and Public Health
• /
• v.15 no.1
• /
• pp.111-114
• /
• 1982

To determine Pb level in blood, we usually .used to pull out about 5ml blood from venous vessel and this sample was digested with acids to decompose organic matter and then determined the Pb contents by Atomic Absorption Spectrophotometer with flame. But recent trend in quan titating Pb in small amount of sample is very much recommended in clinical chemistry specially pediatrics, and industrial hygiene and occupational health area. Authors tried to determine Pb contents in small amount blood of $25{\mu}l$ by using capillary tube method and got the possibility of determination of ng amount of Pb in $25{\mu}l$ whole blood sample without any pretreatment of sample.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
• /
• 2002.04a
• /
• pp.62-65
• /
• 2002

Permeable reactive barriers (PRBs) are in-situ barriers constructed in a subsurface to treat contaminated groundwater using various reactive media. The common reactive medium used in PRB is zero-valent iron, which has been widely used to treat chlorinated solvents (i.e., PCE, TCE). A disadvantage of iron media is high cost. In this study, waste foundry sands were tested to determine the feasibility of their use as a low cost reactive medium. Batch and column tests were conducted with TCE to determine transport parameters and reactivity of the foundry sands. The reactivities of foundry sands for common groundwater contaminants are comparable to or slightly higher than those for Peerless iron, a common medium used in PRBs. In addition, the TOC and clay in foundry sands can significantly retard the movement of target contaminant, which may result in lower effluent concentration of contaminant due to biodegradation. In general, PRBs 1-m thick can be constructed with many foundry sands to treat TCE provided the zero-valent iron content in the foundry sand is higher than 1%.

• Journal of Welding and Joining
• /
• v.4 no.2
• /
• pp.47-52
• /
• 1986

Friction Welds are formed by the mechanisms of diffusion as well as mechanical inter-locking. The severe plastic flow at the interface by the forge action of the process brings the subsurface so close together that detection of any unbounded area becomes very difficult. No reliable method is available so fat to determine the weld quality nondestructively. The paper presents an attempt to determine weld strength quantitatively using the ultrasonic pulseecho method. The new approach calculates the coefficient of reflection based on measured amplitudes of the echoes. This coefficient provides a single quantitative measurement which involves both acoustic energy reflected at the welded interface as well as transmitted across the interface. As a result, it was known that the quantitative relationship between the coefficient and the weld strength (torsional strength) could be drawn.

• Journal of Korean Society of Water and Wastewater
• /
• v.10 no.3
• /
• pp.55-63
• /
• 1996

Nitrification reaction consists of two reactions: nitritification which oxidizes ammonia nitrogen to nitrite nitrogen and nitratification which oxidizes nitrite nitrogen to nitrate nitrogen. Each reaction is carried out by Nitrosomonas and Nitrobacter, respectively. The effective maximum growth rates for both bacteria have to be determined to design aeration tank whenever the aeration tanks have to nitrify ammonia nitrogen in influent. And these values are very important to use mathematical models such as IAWPRC model to simulate nitrification in activated sludge. There are several methods to determine these valves, however, the Fed-Batch experiments can determine these values within 72 hours. In this study, the mathematical equations and experimental procedures for Fed-Batch test are presented. Also, the experimental data and reported values are compared. The estimated mean values of maximum specific growth rates for Nitrosomonas and Nitrobacter are $0.5010day^{-1}$ and $0.6704day^{-1}$, respectively.