• Environmental Analysis Health and Toxicology
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• v.21 no.1 s.52
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• pp.81-86
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• 2006

Embryotoxicity tests were performed in Daphnia magna to assess aquatic ecotoxicity of bisphenol A, a well known industrial compound showing estrogen-like activity in vivo, and to examine their effectiveness in the toxicological assessment. The whole embryonic developmental period was classified into 6 stages and developmental abnormality was checked to evaluate the embryotoxicity. In the present study, bisphenol A showed the ability to interfere with embryonic development, suggesting its antiecdysteroidal activity. The rates of mortality, delayed development, deformity and immobility all showed good concentration-response relationship, demonstrating their possibility as useful toxicological indices in daphnid embryotoxicity tests that have been rarely performed so far. It seemed favorable to the test sensitivity that embryos are removed from maternal daphnids around 7 hr after deposition from the ovaries to the brood chamber. These results suggest that daphnid embryotoxicity tests can be one of useful tools available for the assessment of ecotoxicity of various chemicals in the aquatic environment.

• IEMEK Journal of Embedded Systems and Applications
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• v.9 no.4
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• pp.211-217
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• 2014

Cyber-Physical Systems(CPS) that mostly provides safety-critical and mission-critical services requires high reliability, so that system testing is an essential and important process. Hardware-In-the-Loop Simulation(HILS) is one of the extensively used techniques for testing hardware systems. However, most conventional HILS has problems that it is difficult to support a distributed operating environment and to reuse a HILS platform. In this paper, we introduce EcoHILS(ETRI CPS Open Human-Interactive hardware-in-the-Loop Simulator) in order to test CPS effectively. Moreover, feasibility tests and performance tests of EcoHILS are performed to confirm its effectiveness.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.5 no.5
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• pp.11-21
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• 2002

A series of model tests is performed to evaluate the relationship between soil and a buried pipe in soil undergoing lateral movement. As the result of the model tests, a wedge zone and plastic flow zones could be observed in front of the pipe. And also an arc failure of cylindrical cavity could be observed at both upper and lower zones. Failure shapes in both cohesionless and cohesive soils are nearly same, which was investigated failure angle of $45^{\circ}+{\phi}/2$. In the cohesionless soil, the higher relative density produces the larger arc of cylindrical cavity. On the basis of failure mode observed from model tests, the lateral earth pressure acting on a buried pipe in soil undergoing lateral movement could be applying the cylindrical cavity extension mode. The deformation behavior of soils was typically appeared in three divisions, which are elastic zones, plastic zones and pressure behavior zones.

• Journal of Auto-vehicle Safety Association
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• v.12 no.4
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• pp.7-12
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• 2020

Recently, automobile industries have developed ADAS, smart cars, connected cars, automated driving systems, which use a variety of sensor systems - ultrasonics, cameras, lidars and radars - and communication systems. It is necessary to examine the electromagnetic immunity of vehicles equipped with the sensor systems due to the fact that the normal operation of those systems is very important to the safety of the vehicles. The electromagnetic immunity tests are carried out in an electromagnetic semi anechoic chamber, which is cut off from the outside. It is difficult to create test environments in which the camera sensor systems of vehicles work properly in the test chamber. In this study, test jigs were designed and tested and as a result they are shown to be effective to create test environments for electromagnetic immunity tests of vehicles equipped with camera sensors. We also proposed additional safety standards for immunity tests of vehicles with camera systems that currently do not exist.

• Transactions of the Korean Society of Pressure Vessels and Piping
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• v.19 no.2
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• pp.117-129
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• 2023

Hydrogen embrittlement of a pipe is an important factor in hydrogen transport. To characterize hydrogen embrittlement, tensile and fracture toughness tests should be conducted. However, in the case of hydrogen-embrittled materials, it is difficult to perform tests in hydrogen environment, particularly at low temperatures. It would be useful to develop a methodology to predict the fracture toughness of hydrogen-embrittled materials at low temperatures using more efficient tests. In this study, the fracture toughness of API X52 steels in hydrogen at low temperatures is predicted from numerical simulation using coupled finite element (FE) damage analyses with FE diffusion analysis, calibrated by analyzing small punch test data.

• Korean Journal of Child Studies
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• v.27 no.3
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• pp.271-284
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• 2006

In order to define their relative influence, this study analyzed causal relationships between academic achievement of elementary school students and such related variables as self-esteem and the psychological and economic environment of the home, including clarification of other significant variables affecting academic achievement. Participants were a sample of 485 5th grade students from 8 elementary schools in Busan. Correlation, analysis of covariance structure modeling, and model-fitness tests were applied to the data. Results indicated that the psychological environment of the home has the most significant influence on the academic achievement of children, and the economic environment of the home and self-esteem have relatively low or indirect influence.

• Journal of Aerospace System Engineering
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• v.15 no.4
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• pp.40-46
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• 2021

At launch, satellites are exposed to various types of structural loads, such as quasi-static loads, sinusoidal vibrations, acoustic/random vibrations, and shocks. The launch environment test is aimed at verifying the structural stability of the test object against the launch environment. Various types of launch environments are simulated by simple vibration, acoustic, and shock tests considering possible test conditions in ground. However, the difference between the launch environment and the test environment is one of the causes of excessive testing. To prevent overtesting, a notching technique that adjusts the frequency range and the input load considering the design load is applied. For notching, specific procedures are established considering the satellite development concept, selected launch vehicle, higher system requirements, and test target level. In this study, the notching method, established procedure, and development of a notching toolkit for efficient testing are described.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2005.10a
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• pp.55-57
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• 2005

• Communications for Statistical Applications and Methods
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• v.6 no.2
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• pp.533-542
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• 1999

Widespread of internet causes rapid changes in many areas of statistics such as statistical computation and education. In this paper the efficient methods for statistical software development on the internet environment are introduced. Also the developed examples about monte-carlo permutation tests for two-way contingency tables using Microsoft COM (Component Obejct Model) technology are presented.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2001.09a
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• pp.47-50
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• 2001

The laboratory tests were peformed to investigate the relationship between electrical resistivity and the unsaturated subsurface condition and to evaluate the contamination due to leachate based on measuring electrical resistivity. For weathered granite soil, the electrical resistivity of soil decreases as moisture density increases. The electrical resistivity of soil decreases as the concentration of leachate in pore fluid increases since leachate contains various ionic constituents. And the modified Archie's equation for applying to unsaturated sand is derived by regression analysis.