• Proceedings of the Korean Radioactive Waste Society Conference
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• 2004.02a
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• pp.42-50
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• 2004

The pool $(3m{\times}6m{\times}10m{\times}$ in Irradiated Materials Examination Facility is generally used to transport irradiated materials between a moving cask and hot-cell. During the operation in the pool such as loading/unloading the cask, holding specimen and bucket elevation, water maybe contaminated by radioactive or contaminated impurities from irradiated materials. Then, it must be purified and filtered continuously to keep lower radioactivity than that of regulation prescribed by RCA Korea Activity in a part of radioactive contamination control. This paper described radioactive contamination distribution of water as transported materials, which is related to effective operation of purification and filtration system.

• Journal of Korean Society for Atmospheric Environment
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• v.12 no.1
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• pp.29-41
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• 1996

The two-stage numerical model was used to study the relation between three-dimensional local wind model, advection/diffusion model of random walk method and second moment method on Pusan coastal area. The first stage is three dimensional time-dependent local wind model which gives the wind field and vertical dirrusion coefficient. The second stage is advection/diffusion model which uses the results of the first stage as input data. First, wind fields on Pusan coastal area for none synoptic scale wind showed typical land and sea breeze circulation, and convergence zone occured at 1200LST in northern of domain, in succession, moved northward of domain. Emissions from Sinpyeong industrial district were trasnported toward the inland by sea breeze during daytime, and reached the end part of domain about 1800LST. During nighttime, emissions return to sea by land breeze and vertical diffusion also contributes to upward transport. In order to use this model for forecast of air pollution concentration on the Pusan coastal area, it is necessary that computed value must be compared with measured value and wind fields model must also be dealt in detail.

• Journal of Environmental Science International
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• v.11 no.9
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• pp.907-914
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• 2002

Various Eulerian-Lagrangian models for the one-dimensional longitudinal dispersion equation in nonuniform flow were studied comparatively. In the models studied, the transport equation was decoupled into two component parts by the operator-splitting approach; one part is governing advection and the other is governing dispersion. The advection equation has been solved by using the method of characteristics following fluid particles along the characteristic line and the results were interpolated onto an Eulerian grid on which the dispersion equation was solved by Crank-Nicholson type finite difference method. In the solution of the advection equation, Lagrange fifth, cubic spline, Hermite third and fifth interpolating polynomials were tested by numerical experiment and theoretical error analysis. Among these, Hermite interpolating polynomials are generally superior to Lagrange and cubic spline interpolating polynomials in reducing both dissipation and dispersion errors.

• 한국전산유체공학회:학술대회논문집
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• 2003.10a
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• pp.160-161
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• 2003

Thermocapillary convection is a surface tension driven flow due to a temperature gradient along an interface. It occurs during a crystal-growth process and therefore understanding the convection is important to material processing in microgravity. Although modelling of the float-zone crystal-growth process has been of interest for a few decades, most studies of liquid bridges assumed non-deformable flat surfaces. In reality, the surface profile, g(t,z), is unknown and should be obtained as a solution to the coupled transport equations along with the surface force balance. Here we report on a numerical study of axisymmetric thermocapillary convection in liquid bridges with deformable surfaces. The interface is determined as part of the complete solution. The influence of the capillary number (Ca), Reynolds number (Re), Prandtl number (Pr) and aspect ratio(Ar) on the dynamics is explored.

• Proceedings of the Korean Society of Marine Engineers Conference
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• 2005.11a
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• pp.94-97
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• 2005

Seaworthiness is an important part of the carrier's obligation in the carriage of goods by sea. Especially seaworthiness of the ship is one of the most important obligations of the carrier in the field of international transport law. Therefore it will be important to examine the expected impacts by adopting a continuing duty of seaworthiness in UNCITRAL Draft Instrument from the Korea point of view because Korean Commercial Act provides that carriers are only obliged to exercise due diligence to make the ship seaworthy before and at the beginning of the voyage. This paper examines the concept of the seaworthiness and analyses the provisions of the Draft Instrument for the duty of seaworthiness in comparison with the Korean Commercial Act.

• Proceedings of the KSR Conference
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• 2010.06a
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• pp.1885-1891
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• 2010

Recently metropolitan local governments is actively introducing urban railway's expand and light rail transit as a means of new transport system. DC electricity feeder system operating in the domestic urban railway is typically a feedback circuit consisted of the contact wire and electric railway vehicle via rail. But stray current is to be defined as a current flowing on a structure that is not part of the intended electrical circuit with respect to a given structure. Stray current is generally results from the leakage of return currents from large DC traction systems that are grounded or have a bad earth-insulated return path. At the place where the current leaves the rail and metallic structures, electrolytic corrosion may take place. This paper presents comparison analysis of field test methods based on criteria of electrolytic corrosion protection of buried metallic structures adjacent to DC traction systems.

• Proceedings of the KSR Conference
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• 2007.11a
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• pp.1012-1017
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• 2007

To reduce the cost and the time of transport in Eurasian railroad networks such as TKR(Trans-Korea Railway), TCR(Trans-China Railway) and TSR(Trans-Siberia Railway) owing to the problem of different track gauges (narrow/standard/broad gauge), it is important to develop the gauge - adjustable wheelset system to adapt easily to these gauges. Moreover, this system accomplishes periodically a conversion operation from the gauge variable segment between different gauge. Gauge adjustable compression coil spring during conversion process accomplishes repetitively a central role for operation mechanism between flange and locking part. Therefore, to assure the safety of the gauge-adjustment wheelset system, it is necessary to stress analysis of the optimized spring in the system. In this study, it was performed to optimal design of the spring for stress analysis by using the genetic algorithm.

• Journal of Industrial Technology
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• v.19
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• pp.279-285
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• 1999

An integrated sewer management system was developed for the analysis of sewer flow and for optimal operation of sewer works using ArcView and SWMM. SWMM and ArcView were dynamically linked together using Avenue in order to construct user-friendly management system. The developed system was applied to a residential area in Choonchun city to verify its utilities. All the relevant field data were analyzed on the basis of developed system, and the modeling of sewer flow was implemented using RUNOFF, EXTRAN, TRANSPORT in SWMM. This system is now in the process of connection to the management system of watershed and surface environment in order to develope an integrated environmental management system. Futhermore, this system will be a critical part of overall control system of sewer works including sewer line and wastewater treatment plant. As this system can provide comprehensive prediction of flow and pollution profiles, it could serve as a tool not only for optimal management, but also for decision support system to examine the efficiency of planning and implementation of sewer projects.

• Journal of the Korean Society of Safety
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• v.15 no.4
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• pp.15-19
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• 2000

The exact estimation of the ductile crack growth in a thin sheet would be needed in part of the commercial transport aircraft industry fields. A 2-dimensional elastic plastic finite element analysis was carried out to simulate a stable crack extension in a thin sheet 2024 aluminium alloy. Two kinds of crack modeling were used to evaluate curves of the stable crack extension. And then CTOA(crack tip opening angle) and CTED(crack tip energy density) were calculated in order to determine whether they can be used as useful crack extension criterions in a thin sheet. Results indicate that stable crack extension behaviors were simulated well and CTED is more admirable even though CTOA also is reasonable as a criterion for a stable crack extension in a thin 2024 aluminium alloy sheet.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.15 no.5
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• pp.434-445
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• 1990

Protocol testing techniques are expanded from the traditional simple function- testing based on the OSI model, to sophisticated performance testing, conformance testing and interoperability testing. In addition, both point-to-point and point-to-multipoint protocols are to be covered. This paper presents a new multiple-purpose protocol test system where the common platform includes the test sequence generation and test result analysis, and the modular test execution part is selectively adjusted according to the test purposes and protocols under test. This paper describes test system for network routing protocol and test system for transport protocol, designed upon the ideas of the multiple-purpose protocol test system.