• Journal of Korean Ophthalmic Optics Society
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• v.8 no.2
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• pp.1-11
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• 2003

A mathematical model was proposed to analyze the oxygen diffusion reaching the cornea through the tear layers and contact lens based on Fick's law and the principle of continuity of the diffusion flux through the each layers. The model predicts how the parameters such as the thickness of tear layer on the cornea, both the Dk and thickness of contact lenses etc., affect the oxygen tension at cornea and oxygen flux entering the cornea. It is found that either too flat or too tightly fitted contact lenses can cause the oxygen deficiency inside the periphery of the cornea because of the reduction of oxygen flux resulted from too thickened tear layer.

• Transactions of the Korean hydrogen and new energy society
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• v.18 no.3
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• pp.284-291
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• 2007

The Ni-MH batteries for HEV and industry are normally placed in outdoor, consequently causing an too weak discharge power problem due to a cold weather specially in winter time. In order to improve the low temperature performances of the Ni-MH battery for HEV and industrial uses, it has been investigated the low temperature discharge characteristics of Ni-MH battery with various electrolytes at $-18^{\circ}C$. The summary of experimental results are as follows. The low temperature characteristics depended strongly on the characteristics of electrolytes. When the concentration of the electrolytes were too high or too low the low temperature performance was poor. The best electrolyte was composed of KOH 6.2M+LiOH 1.2M. An addition of RbOH or CsOH to electrolyte improved the low temperature performance. The best total concentration of electrolyte composed of KOH, NaOH and LiOH was about 7M.

• Korea journal of population studies
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• v.13 no.1
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• pp.3-25
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• 1990

Life table of Korean population for years 1983 1985 1987 and 1989 were constructed byt the National Bureau of Statics. The ago specific death rates were calculated froom the death registral ion for numerators and the estimated population by age and sex for denominators. In the course of constructing life tables, we have maole some adjustments for deficiencies in regist rat ion olata as follows. First, the non-registered portion oof infant deaths especially for neo-natal deaths was estirnateol and added too the original data. The main reason is that deaths occorring in the neo-natal period and prior to the registrat ion of birth leave little incentive for the registration of either the birth or the death. Second. t he do~hayed p(ortioon of deaths registering after one year of occurrence was estimated and added too the original data. Third t the ptortioon haying in, occuracies in ,~oge reporting was also estimated. Fourth the moving average methood was finally employed in an effort too remove the random error. The major fin(hings are as foolloows. 1. the average life expectancy at birth in 1989 is calculateol as 70.8 years in 1989, 2. a gap netween the male and female life expectancies is widened to more than 8 years toorm 1.8 years in 1906 10. It means that the female life expectancy has increased substantially, 3. the death rates of the middle - aged men starting age 40 are found to he relatively higher than those of females and younger age groups. This peculiar pattern was also found with the comparison of those of other countries.

• Proceedings of the KIEE Conference
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• 1992.07a
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• pp.288-289
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• 1992

The method of simulated annealing is a technique that has recently attracted significant attention as suitable for optimization problem of very large scale. If the temperature is too high, then some of the structure created by the heuristic will be destroyed and unnecessary extra work will be done. If it is too low then solution is lost, similar to the case of a quenching cooling schedule in the Simulated Annealing (SA) phase. Therefore, a crucial issue in this study is the determination of the starting temperature and cooling schedule for SA phase.

• Journal of the Korean Society of Safety
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• v.19 no.3 s.67
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• pp.9-13
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• 2004

To confirm the previous finding that FDS predicts a fire growth rate too rapid compared with an experiment in a center fire in a room with an opening, the same computational fluid dynamics was applied to two types of fires, wall fire and comer fire. First the grid size was chosen to eliminate possible numerical errors due to a coarse grid system. Then the two types of fires were simulated for three different fire sizes, 7.65, 21.25, and 51.57kW for each type, which are the same as in the experiment to be compared with. The fires were predicted to grow too fist although the average temperatures and heights of the neutral planes were in good agreement with measurement.

• Journal of Industrial Technology
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• v.20 no.B
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• pp.45-53
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• 2000

A numerical study is done on the thrust vector control using gaseous secondary injection in the rocket nozzle. A commercial code, PHOENICS, is used to simulate the rocket nozzle flow. A $45^{\circ}-15^{\circ}$ conical nozzle is adopted to do numerical experiments. The flow in a rocket nozzle is assumed a steady, compressible, viscous flow. The exhaust gas of the rocket motor is used as an injectant to control the thrust vector of rocket at the constant rate of secondary injection flow. The injection location which is on the wall of rocket is chosen as a primary numerical variable. Computational results say that if the injection position is too close to nozzle throat, the reflected shock occurs. On the other hand, the more mass flow rate of injection is needed to get enough side thrust when the injection position is moved too far from the throat.

• Korean Journal of Heritage: History & Science
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• v.37
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• pp.213-242
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• 2004

"China", "Guang-Xi(廣西)", "Dong-Shan(東山)", a marriage of "Yao-zu(瑤族)" divide mainly into a distinguished family form, but are by a marriage of a traditional general form (a woman getting married) and "Zhaoxu-Hun(招婿婚)", a marriage of "Liangtou-che(兩頭扯)". These two marriage format that mentioned the back is a marriage format to often appear in other Chinese minority race region while being a custom peculiar to "Yao-zu(瑤族)" marriage method. "Zhaoxu-Hun(招婿婚)" provides labor force as a workman while living with a man sinks with "son-in-law" to a woman house, and doing, and it is to carry out a lot of duty as a husband too. "A Liangtou-che(兩頭扯)" marriage is more characteristic, but lives while going around a bilateral family while man and woman each stay in an own house. There are inheritance of property rights to own family, too and obeys anger of he direction family bilateral where if lays a child even if stands up and holds a memorial service. At the same time that these marriages are performed between the same "Yao-zu(瑤族)" near a track, and solution does a distribution problem between a labor problem and the families which were unstable through a mutual marriage for the purpose a compunction "Yao-zu(瑤族)" social network construction into intimacy anger. A general idea is covered he base with in order the porcelain which is a weak race prevent that it is assimilated by external aggression because "Yo-zu(瑤族)" has always received aggression of "a Han-zu(漢族)" too historically, and to keep an ethnic pure blood.

• Journal of Korea Game Society
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• v.2 no.2
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• pp.46-51
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• 2002

In this study, a real-time simulation method for the phenomena, which are too complex to be simulated during real-time computer games, was proposed based on the neural network. The procedure of proposed method is to 1) obtain correlation data between input parameters and output parameters by mathematical modeling, code analyses, and so on, 2) train the neural network with the correlation data, 3) and insert the trained neural network in a game program as a simulation module. For the case that the number of the input and output parameters is too high to be analyzed, a method was proposed to omit parameters of little importance. The method was successfully applied to severe accidents of nuclear power plants, reflecting that the method was very effective in real time simulation of complex phenomena.

• Journal of Information Technology Applications and Management
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• v.27 no.2
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• pp.37-50
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• 2020

This paper is very exploratory and addresses the issue 'Is a general quality model of software possible?'. If possible, how specific can/should it be?' ISO 25000 Series SQuaRE is generally regarded as a general quality model which can be applied to most kinds of software. Usability is one of the 8 characteristics of SQuaRE's Product Quality Model. It is the main issue associated with SQuaRE's Quality in Use Model too. it is the most important concept associated software quality since using is the only ultimate goal of software products. Playability, however, is generally regarded as a special type of usability, which can be applied to game software. This common idea contradicts with the idea that SQuaRE is valid for most kinds, at least many kinds, of software. The empirical evidences of this paper show that SQuaRE is too specific to be a general quality model of software.

• Journal of the Korean Mathematical Society
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• v.32 no.2
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• pp.211-236
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• 1995

The purpose of this paper is to provide a transient diffusion approximation of queue size distribution for M/G/m/N system. The M/G/m/N system can be expressed as follows. The interarrival times of customers are exponential and the service times of customers have general distribution. The system can hold at most a total of N customers (including the customers in service) and any further arriving customers will be refused entry to the system and will depart immediately without service. The queueing system with finite capacity is more practical model than queueing system with infinite capacity. For example, in the design of a computer system one of the important problems is how much capacity is required for a buffer memory. It its capacity is too little, then overflow of customers (jobs) occurs frequently in heavy traffic and the performance of system deteriorates rapidly. On the other hand, if its capacity is too large, then most buffer memories remain unused.