• Korean Journal of Mathematics
• /
• v.16 no.4
• /
• pp.545-551
• /
• 2008

We investigate the multiple solutions for a parabolic boundary value problem with jumping nonlinearity crossing no eigenvalues. We show the existence of the unique solution of the parabolic problem with Dirichlet boundary condition and periodic condition when jumping nonlinearity does not cross eigenvalues of the Laplace operator $-{\Delta}$. We prove this result by investigating the Lipschitz constant of the inverse compact operator of $D_t-{\Delta}$ and applying the contraction mapping principle.

• IE interfaces
• /
• v.13 no.2
• /
• pp.253-257
• /
• 2000

This study was conducted to test the significance of differences in the tactual difference thresholds and perception time for tactual direction type and finger type and radius size based on small circular button. The results show that difference threshold of vertical tactual perception is significantly greater than horizontal perception, but there are no significant differences in difference thresholds among finger types and radius sizes. Also, there are no significant differences in tactual perception time among tactual direction types, finger types, and radius types. These findings are applicable for tactual user interface design.

• Proceedings of the Korean Society of Toxicology Conference
• /
• 2003.10b
• /
• pp.164-164
• /
• 2003

We show that PCSC, a polysaccharide isolated from the sclerotium of Poria cocos with one percent sodium carbonate, significantly induces nitric oxide (NO) production and inducible NO synthase (iNOS) transcription through the activation of nuclear factor-$\kappa$B/Rel (NF-$\kappa$B/Rel).(omitted)

• Communications of the Korean Mathematical Society
• /
• v.11 no.1
• /
• pp.81-87
• /
• 1996

We will construct polynomials of degree 6 in z and $\bar{z}$ on $C^2$ which gives, via its coefficient $\beta$ as a parameter, a family of pseudoconvex domains $\Omega_\beta$ in $C^2$ with the origin being a boundary point, and show that the domains $\Omega_\beta$ has no peak functions of class $c^1$ at the origin and has no holomorphic support functions for $1 \leq \beta < \frac{9}{5}$.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2004.03a
• /
• pp.802-806
• /
• 2004

For the protection of the local air quality and the global atmosphere, the emissions of trace species including nitric oxides (NO and NO$_2$) from gas turbines are regulated by local governments and by the International Civil Aviation Organization. In-situ measurements of such species are needed not only for the development of advanced low-emission combustion concepts but also for providing emissions data required for the sound assessment of the effects of the emissions on environment. We have been developing a laser absorption system that has a capability of simultaneous determination of NO and NO$_2$concentrations in the exhaust jets from aero gas turbines. A diode laser operating near 1.8 micrometer is used for the detection of NO while a separated visible tunable diode laser operating near 676 nanometers is used for NO$_2$. The sensitivities at elevated temperature conditions were determined for simulated gas mixtures heated up to 500K in a heated cell of a straight 0.5 m optical path. Sensitivity limits estimated as were 30 ppmv-m and 3.7 ppmv-m for NO and NO$_2$, respectively, at a typical exhaust gas temperature of 800K. Experiments using the simulated exhaust flows have proven that $CO_2$ and $H_2O$ vapor - both major combustion products - do not show any interference in the NO or NO$_2$ measurements. The measurement system has been applied to the NO/NO$_2$ measurements in NO and NO$_2$ doped real combustion gas jets issuing from a rectangular nozzle having 0.4 m optical path. The lower detection limits of the system were considerably decreased by using a multipass optical cell. A pair of off-axis parabola mirrors successfully suppressed the beam steering in the combustion gas jets by centralizing the fluctuating beam in sensor area of the detectors.

• Proceedings of the KIEE Conference
• /
• 1995.07c
• /
• pp.1223-1225
• /
• 1995

The $NO_2$ gas-detection characteristics were investigated using the functional organic Langmuir-Blodgett(LB) films of Copper-tetra-tert-butylphthalocyanine(CuTBP). The optimum conditions for a film deposition were obtained through a study of $\pi$-A isotherms, and the deposited film status was confirmed by the ellipsometry measurements. The $NO_2$ gas response experiments under 200 ppm concentration at room temperature show that there are increment of electrical conductivity by 40 times and 25 seconds of response time, and 40 seconds of recovery times.

• Environmental Engineering Research
• /
• v.23 no.1
• /
• pp.107-113
• /
• 2018

Air quality and pollution have recently become a major concern; vehicle emissions significantly pollute the air, especially in large and crowded cities. There are various factors that affect vehicle emissions; this research aims to find the most influential factors affecting $CO_2$ and $NO_x$ emissions using Adaptive Neural Fuzzy Inference System (ANFIS) as well as a systematic approach. The modified ANFIS (MANFIS) was developed to enhance modelling and Root Mean Square Error was used to evaluate the model performance. The results show that percentages of $CO_2$ from trucks represent the best input combination to model. While for $NO_x$ modelling, the best pair combination is the vehicle delay and percentage of heavy trucks. However, the final MANFIS structure involves two inputs, three membership functions and nine rules. For $CO_2$ modelling the triangular membership function is the best, while for $NO_x$ the membership function is two-sided Gaussian.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.58 no.7
• /
• pp.1375-1379
• /
• 2009

Insulation tests have been performed on two generator stator bars under accelerated aging under a laboratory environment. Electrical stress was applied to stator bar No.1, and electrical and thermal stresses were applied to stator bar No.2. Nondestructive stator insulation tests including the ac current, dissipation factor($tan{\delta}$), and partial discharge tests have been performed on both bars as the bars were aged for 11460 hours. Experimental test results show that ${\Delta}I$, ${\Delta}tan{\delta}$, and partial discharge of No. 1 and No.2 stator bars increased with increased in aging time. It has been concluded from the test that the stator insulation of the two generators are in good condition.

• IE interfaces
• /
• v.17 no.2
• /
• pp.242-248
• /
• 2004

Lot-streaming is the process of splitting a job (lot) into a number of smaller sublots to allow the overlapping of operations between successive machines in a multi-stage production system. A new genetic algorithm (NGA) is proposed for minimizing the mean weighted absolute deviation of job completion times from due dates when jobs are scheduled in a no-wait lot-streaming flow shop. In a no-wait flow shop, each sublot must be processed continuously from its start in the first machine to its completion in the last machine without any interruption on machines and without any waiting in between the machines. NGA replaces selection and mating operators of genetic algorithms (GAs), which often lead to premature convergence, by new operators (marriage and pregnancy operators) and adopts the idea of inter-chromosomal dominance. The performance of NGA is compared with that of GA and the results of computational experiments show that NGA works well for this type of problem.

• 한국연소학회:학술대회논문집
• /
• 2005.10a
• /
• pp.104-109
• /
• 2005

This paper describes the effect of the split injection on combustion and emission characteristics in a common rail diesel engine at various operating conditions. The combustion pressures and exhaust emissions such as $NO_x$ and soot were measured at various split injection timings. The experimental apparatus of this study is composed of 4 cylinder engine installed with piezoelectric pressure sensor, EC dynamometer, and exhaust gas analyzer for the measurement of $NO_x$, CO, HC and soot emissions. Results show that the split injection has a great effect on reducing the rapid premixed combustion and $NO_x$ emissions.