• Journal of electromagnetic engineering and science
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• v.11 no.4
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• pp.274-281
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• 2011

High-speed telecommunication systems are influenced by electromagnetic environments because they need a wide bandwidth to transmit signals. Immunity tests of telecommunication equipment are effective for improving its immunity to electromagnetic environments. However, immunity tests are expensive to carry out because there are several different tests. The correlation among the tests should therefore be examined in order to reduce the kinds of tests that are necessary. This paper investigates the correlation between the electrical fast transient/burst (EFTB) test and the radio frequency (RF) conductive immunity test. Imitation equipment was constructed with a balun, and a baseband signal was transmitted from the associated equipment to the imitation equipment. Then, disturbances were applied to the equipment, and the telecommunication quality was evaluated by using the bit error rate (BER). The results from the EFTB test indicated that the BER was less than $6{\times}10^{-5}$ and the value was independent of the peak value. The results from the RF conductive immunity test indicated that the BER was affected by the longitudinal conversion loss (LCL).

• KIEAE Journal
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• v.7 no.5
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• pp.35-40
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• 2007

The purpose of this study is to execute evaluation experiment to know the evaluation property of lighting environment of residential space for senior people, considering visual characteristics along aging, and finally provide basic data for the lighting plan to ensure the visual amenity. Processes of this study are as follows;1) Analyzed the variation property of visual sensibility and visual ability of senior people along aging. 2) Selected 3 types of life behavior(rest, conversation and reading) after checking life behavior in residential space for senior people based on advanced study. 3) Made the Mock-up Model that Dimming is possible, actual furnace to model. 4) Executed sensitivity evaluation experiment about lighting environment. 5) Analyzed evaluation property of lighting environment of residential space for senior people. Results of this study are as follows, 1) With lens-filter, we got comfort and amenity in bulb-color lamp which has similar color temperature with red of lens filter. 2) Lighting environment tests during conversation : With lens filters, they felt comfort on bulb color in case of higher illuminance than 850lux and daylight color in 500lux. 3) Lighting environment tests at reading : With lens filter, bulb color got better score in brightness and appropriateness than daylight color.

• Research in Mathematical Education
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• v.16 no.1
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• pp.1-13
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• 2012

This paper explores gifted students' reasoning abilities. Three tests were developed in order to assess and analyze their reasoning abilities building on previous research on covariational reasoning. Giving consideration to the arising problems in the tests, we constructed a LOGO-based JavaMAL microworld environment which engages students in an active learning environment. This environment was designed by applying 'instrumental approach' in microworld. Based upon the post test results, the role of activity in microworld environment as 'instrument mediated activity' is also discussed.

• Journal of Korean Society on Water Environment
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• v.28 no.5
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• pp.762-767
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• 2012

The ecotoxicity assessment of nanomaterials (NMs) in the environment is actively conducted throughout the world because of the concerns about their potential risk from usage and release into the environment, as well as their unique physiochemical properties. Ecotoxicity tests for NMs have been conducted using various species and methods; however, in spite of these efforts, the characteristics and toxicity of NMs have not been defined. The fish embryo toxicity test (FET) has been conducted extensively to evaluate the toxicity of NMs as an alternative to a whole-body test in fish. In this study, we collected and analyzed the trends of nanotoxicity on the early development of freshwater fish. The model nanomaterials are carbon NMs ($C_{60},\;C_{70},\;C_{60}$(OH)n and carbon nanotube). Their adverse effects were extensively investigated based on the properties of NMs, test species, and diverse exposure conditions.

• Journal of the Korean Society of Groundwater Environment
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• v.6 no.1
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• pp.14-22
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• 1999

Slug and pumping tests have been widely used to obtain hydraulic parameter estimates in the field. Although a variety of sources of error and uncertainty can be involved in the course of the test performance and data analysis, serious considerations on these sources are often neglected. In this study these various sources of error and uncertainty are analyzed or discussed using repeated slug and pumping test data and some guide lines are suggested to improve quality of parameter estimates from the slug and pumping tests.

• Wind and Structures
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• v.7 no.3
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• pp.203-214
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• 2004

This paper describes a method for developing a multi-degree-of freedom aero-elasto-plastic model of a base-isolated mid-rise building. The horizontal stiffness of isolators is modeled by several tension springs and the vertical support is performed by air pressure from a compressor. A lead damper and a steel damper are modeled by a U-shaped lead line and an aluminum line. With this model, the frequency ratio of torsional vibration to sway vibration, and plastic displacements of isolation materials can be changed easily when needed. The results of isolation material tests and free vibration tests show that this model provides the object performance. The peak displacement factors are about 4.5 regardless of wind speed in wind tunnel tests, but their gust response factor decreases with increment of wind speed.

• Journal of Soil and Groundwater Environment
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• v.16 no.3
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• pp.3-9
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• 2011

Partitioning tracers have been used with non-partitioning, inert tracer such Br, for detection, estimation, and monitoring of remediation performance of the subsurface contaminated with nonaqueous phase liquids (NAPLs). Various partitioning tracers with different partition coefficients between aqueous and nonaqueous phase liquids can be used to determine the hydraulic conductivity, dispersivity, and residual mass of NAPLs in the subsurface soil matrices. Temporal moment-generating equations were used to analyze the field pilot-scale test results. The pilot-scale tests included conservative tracer tests and partitioning tracer tests. Analyses of nonaqueous phase liquid distribution and characteristics of groundwater bearing soil media were performed.

• Proceedings of the Korean Geotechical Society Conference
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• 2008.03a
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• pp.97-104
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• 2008

The objective of this study was to investigate the strength characteristics of frozen clay. Compressive strength tests were performed on frozen clay with different water contents at various temperatures. The dry density of specimens and strain rate was kept constant. Test results showed that compressive strength increased with increasing water content and decreasing temperature. The increase in peak strength became more significant the lower the temperature for a given water content. The failure mode changed from brittle to ductile deformation with increasing water content and decreasing temperature. Tests also showed an increase in deformation modulus with increasing peak strength, increasing water content and decreasing temperature.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2004.09a
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• pp.195-198
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• 2004

This study applied EK method to remediate contaminated soil by heavy metal(Pb), tried to increase the efficiency of remediation using zeolite as enhanced EK remediation method to overcome the limit of traditional EK remediation method. Adsorption tests on Pb were conducted to apply the EK extraction and test conditions which contained the electrode reversal, operating time were established. After tests, lead-ions were transported into the specific position of zeolite by EK phenomena, then the immobilization of lead-ions at zeolite was developed. Based on these tests, the efficiency of remediation is different with its test conditions. In addition, the efficiency of remediation was improved dramatically by adding zeolite without electrode reversal and satisfied TCLP regulation of EPA in USA through the whole sample range. Finally, absorption and immobilization capacity of zeolite were proved its excellence and confirmed the possibility of application as enhanced EK remediation method.

• Journal of the Korean Society of Groundwater Environment
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• v.3 no.1
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• pp.9-14
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• 1996

GWW was developed by UN(United Nations) in order to manage groundwater data systematically on PC windows. Temporal and spatial data from lab and field tests are stored in a data base. The data base can be displayed graphically by using the GIS (Geographic Information System) technique. Raw data from pumping tests, step-drawdown tests, and chemical analyses can be analysed to characterize the hydrogeologic system. This article demonstrates a GWW application using default database and groundwater data obtained at the Nanjido Landfill site.