• Journal of Korean Society of Coastal and Ocean Engineers
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• v.3 no.4
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• pp.185-196
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• 1991

A laterally-averaged X-Z numerical model with transformed coordinates is developed to analyze the salinity dispersion in estuaries. Gravitational term, salinity variations with respect to the water depth. and re-evaluation of , salinity boundary condition are examined. Especially. the improvements in stability and accuracy of the numerical algorithm are made by adopting the fractional step method for the dispersion term of the governing equation. The model being applied to the Keum River Esturary, physical and numerical properties of Manning's n and dispersion coefficients are analyzed. Salinity intrusion into the river, influence of upstream river inflows, and salinity distribution for spring/neap tide are also examined.

• Korean Journal of Optics and Photonics
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• v.24 no.1
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• pp.9-16
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• 2013

We try to find the generalized structural equation that gives a perspective understanding for telecentric lenses through paraxial optical algebraic equations and preconditions from a highly experienced design sense. The equation is named the $f{\theta}$ formula and this formula is applied to single lenses, double Gauss lenses, Cooke triplet lenses and the compound lens composed of a Cooke triplet lens and a double Gauss lens step by step. And this formula is also applied to single fly-eye lenses plus a telecentric lens and double fly-eye lenses plus a telecentric lens in sequence. As a result, we can confirm that this $f{\theta}$ formula leads to intuitive optical design with a structural understanding for telecentric lens systems.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.10
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• pp.4378-4384
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• 2012

In LED chip packaging, die bonding is a very important process which fixes the LED chip on the lead frame to provide enough strength for the next process. This paper focuses on the process optimization of a LED die bonding, which attaches small zener diode chip on PLCC LED package frame, using response surface analysis. Design of experiment (DOE) of 5 factors, 3 levels and 5 responses are considered, and the results are investigated. As the results, optimal conditions those satisfy all response objects can be derived.

• Journal of the Korea Computer Graphics Society
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• v.24 no.3
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• pp.43-48
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• 2018

In this paper, we present a method for removing shadows from scanned documents. Compared to the existing methods such as one based on image pyramid representation or adaptive thresholding, our method produces more robust and higher quality results. The basic idea of the approach is to use the local image statistics and to separate interesting regions from the image such as the regions around letters and figures. For the separated regions, we adaptively adjust the local brightness and contrast, and apply the sigmoid function to the intensity values as well to enhance the clarity of the image. For separated the other empty regions, we apply the gradient-base image hole filling method to fill the region with smooth color change.

• Journal of the Korean Institute of Telematics and Electronics
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• v.19 no.5
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• pp.26-31
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• 1982

Texturization technique has been employed to improve the efficiency of Al-MIS solar cells. The best condition for the formation of insulating layer was 50$0^{\circ}C$ in N2 ambient for 20 minutes, and the appropriate thickness of the Al barrier metal layer was about 100$\AA$ For the texturization of the face a mixture of hydrazinehydrate and pyrocathecol was used. The efficiency improvement of the texturized cells ranged from 1.2 to 1.6% under 100mW/$\textrm{cm}^2$ illumination.

• Explosives and Blasting
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• v.22 no.1
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• pp.1-4
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• 2004

The gelatine dynamite, which has been traditionally used in Korea as the 2nd generation explosive, is now being rapidly replaced by an emulsion explosive because of the change in life environment economic schemes, and safety reasons. However, there has been lack of study in the surfactant which is an important factor in manufacturing technology of emulsion explosives, and especially GMB technology has not been used in Korea. In this study, effective usage of surfactant with optimum dosage and optimum mixing temperature of GMB was investigated to increase safety and effectiveness.

• The KIPS Transactions:PartC
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• v.8C no.1
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• pp.1-11
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• 2001

There are several traditional factors of software quality. Some of them are such as correctness, reliability, efficiency, compatibility, portability, etc. In addition to them, security is required as another factor of software quality nowadays because some application programs are used as a way to attack information systems by stack frame manipulation. Each processor has its own peculiar stack frame mechanism and C language uses the characteristics of them. This paper explains the concept of security problem caused by stack frame manipulation, and the stack frame mechanism of Pentium, Alpha and SP ARC processor in detail. And then it examines the effect of stack frame mechanism on the security of programs in C language.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.3
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• pp.1308-1312
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• 2011

CCFL(Cold Cathode Fluorescent Lamp)for BLU of LCD and special lighting has been widely utilized. The removal of oxide film formed on electrode of CCFL in manufacturing process is required. In this pape Plasma treatment was carried out to remove the oxide film. To ensure the optimum process, the analysis of sheet resistance, XRD, AFM and solder test was conducted. A minimum sheet resistance and the maximum percentage of the solder coverage ratio were measured in optimal process conditions such as plasma power consumption 600W and processing time of 70 seconds. As the plasma treatment is confirmed to be due to removal of copper oxide, this process is expected to be used as a treatment of electrode for CCFL.

• 한국HCI학회:학술대회논문집
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• 2009.02a
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• pp.193-196
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• 2009

Most of studies adopt a fixed skin color model to segment skin color region in a single image. The methods, however, result in low detection rates or high false positive error rates since the distribution of skin color is varies depending on the characteristics of input image. For the effective skin color segmentation, therefore, we need a adaptive skin color model which changes the model depending on the color distribution of input image. In this paper, we propose a novel adaptive skin color segmentation algorithm consisting of 2 stages which results in both high detection rate and low false positive error rate.

• 한국전산유체공학회:학술대회논문집
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• 2005.10a
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• pp.117-124
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• 2005

Splitting algorithms of the incompressible Navier-Stokes equations using P1P1/P2P1 finite element formulation are newly proposed. P1P1 formulation allocates velocity and pressure at the same nodes, while P2P1 formulation allocates pressure only at the vertex nodes and velocity at both the vertex and mid nodes. For comparison of the elapsed time and accuracy of the two methods, they have been applied to the well-known benchmark problems. The three cases chosen are the two-dimensional steady and unsteady flows around a fixed cylinder, decaying vortex, and impinging slot jet. It is shown that the proposed P2P1 semi-splitting method performs better than the conventional P1P1 splitting method in terms of both accuracy and computation time.