• The Korean Journal of Applied Statistics
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• v.2 no.1
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• pp.48-53
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• 1989

In contrast to the customary approximations based on standard normal percentage points, direct approximations involve simple functions of parameters (such as degrees of freedom and tail area of the t distributions). This article used techniques of exploratory data analysis following Hoaglin to develop direct approximations for percentage points in the commonly used portions of upper tail of the t distribution with small to moderate numbers of degrees of freedom. These approximations are convenient to use and they compare favorably in accuracy with the popular approximations based on standard normal percentage points such as Peiser's. They can be used as an initial value generator in algorithms for getting more accurate percentage points.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2000.05a
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• pp.406-409
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• 2000

We propose the modified neural network which are paralleled to control nonlinear systems. The proposed method is a direct control method to use inverse model of the plant. Nonlinear systems are divided into two parts; linear part and nonlinear part, and it is controlled by RLS method and recursive multi-layer neural network with each other. We simulate to verify the performance of the proposed method and are compared with conventional direct neural network control method. The proposed control method is improved the control performance than the conventional method.

• Transactions of the Korean Society of Mechanical Engineers
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• v.9 no.2
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• pp.190-201
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• 1985

Direct cutting tests was carried out to evaluate the dynamic performance of lathes under various cutting conditions. Significant factors influencing the chatter limits were identified through use of analysis of variance. Dynamic performances of two lathes were compared and the merits and drawbacks of the direct cutting test were discussed. Exciting-direct-cutting test method was newly proposed as a more rational method of dynamic performance test. The basic theory and experiments of the test were explained. The results shows that the method can be used as a powerful tool for the evaluation and the improvement of dynamic performance of machine tools.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• v.24 no.1
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• pp.93-102
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• 2020

The concept of temperature distribution in inhomogeneous semi-infinite solids is examined by making use of direct integration method. The analysis is done on the solution of the in-plane steady state heat conduction problem under certain boundary conditions. The method of direct integration has been employed, which is then reduced to Volterra integral equation of second kind, produces the explicit form analytical solution. Using resolvent- kernel algorithm, the governing equation is solved to get present solution. The temperature distribution obtained and calculated numerically and the relation with distribution of heat flux generated by internal heat source is shown graphically.

• Journal of Radiation Protection and Research
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• v.28 no.4
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• pp.361-368
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• 2003

The economic and environmental friendliness analysis of the nuclear fuel cycle options that can be expected in Korea were performed. Options considered are direct disposal, reprocessing and DUPIC (Direct Use of Spent PWR Fuel In CANDU Reactors). By considering the result of calculation of the annual uranium requirement and nuclear spent fuel generation by analysis of nuclear fuel material flows in the nuclear fuel cycle options, we decided the time of back-end nuclear fuel cycle processes and the volume. Then we can analyze the economic and environmental friendliness by applying the unit cost and unit value of each process, respectively.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.7 no.4
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• pp.128-134
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• 2008

Models of the deposition heights in the uncontrolled laser aided direct metal deposition process are constructed for the enhancement of the process integrity. Linear and non-linear statistical models as well as fuzzy model are utilized as the modeling methods. The predictability of the models are evaluated with the values of the sum of square error. The algorithm to use the models in the feedback controlled system is suggested to increase the deposition height accuracy within a layer.

• Transactions of the Korean Society of Automotive Engineers
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• v.4 no.4
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• pp.46-57
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• 1996

The direct injection stratified charge(DISC) engine enhances the fuel tolerance and the antiknock tendency. This enhanc3d antiknock tendency allows use of a higher compression ratio which results in higher thermal efficiency. But its actual utilization is prevented by high emission combustion time and wall quenching will be the main causes of increasing unburned hydrocarbons in DISC system. In order to solve this problem, small aount of hydrogen was added to the charging air or injected fuel. The effects of hydrogen addition were examined experimentally by radial fuel injection using a pancake-type constant volume bomb. In case of the hydrogen addition to the charge of air, the combustion the amount of hydrogen. In case of the hydrogen addition to the fuel, the combustion pressure was significantly increased.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.560-560
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• 2012

We report a one-step fabrication method of Poly(9,9-dioctylfluorene) (PFO) nanowire array with pronounced ${\beta}$-Phase. We use liquid-bridge-mediated nanotransfer molding (LB-nTM) which is a new direct nano-patterning method based on the direct transfer of various materials from a mold to a substrate via liquid layer. The formation of the ${\beta}$-phase morphology in the resulting PFO nanowire array was evidenced by the presence of an absorption peak at 435nm. With the collection polarizer oriented parallel to the wire long axis, the PL emission was most intense and an emission dichroic ratio, DRE, of 3.7 was determined. The nanowire array have been investigated by scanning electron microscopy (SEM). Also, we simply fabricated structure of device of ITO/PFO nanowire arrays/Al and the electroluminescence spectra were recorded at various applied voltage.

• Magazine of the Korean Society of Agricultural Engineers
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• v.44 no.4
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• pp.123-128
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• 2002

This study was performed to use fiber mixed soil which has clayey soil or sandy soil with fibrillated fiber or monofilament fiber on purpose of construction materials, filling materials, and back filling materials. In addition, this study was conducted to analyze strength properties and fiber reinforcing effect with fiber mixed soil by direct-shear test. In case of fibrillated fiber mixed soil, the more quantity of fiber was in both cohesive soil and sandy soil, the larger shear stress was in respective step of normal load. The respective mixed soil at 0.5% and 0.1% mixing ratio of monofilament fiber mixed soil showed maximum shear stress. According to unconfined compression or direct-shear test, making specimen of the monofilament fiber mixed soil, it is required to be careful and stable mixing method, while it is expected that monofilament fiber mixed soil doesn't increase strength.

• Journal of Aquaculture
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• v.12 no.1
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• pp.71-77
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• 1999

The potential utility of injection media (sucrose, PEG, and liposome) was demonstrated for direct gene transfer into olive flounder (Paralichthys olivaceus) muscles. Based on the use of sucrose (final cone. 20%), PEG 8,000 (final cone. 10%) or liposome (twice us of DNA injected), the present injection strategy significantly improved the level of transgene expression as well as persistent duration of expression. The increased amounts of expression in DNA injection with sucrose, PEG, and liposome were as high as from 2.1 to 4.9-folds of conventional TE-based DNA injection. The best result was obtained from injections of liposome-encapsulated DNA in which the expression was detectable at least 32 days after injection when compared to only 8-16 days from TE-based injections.