• Journal of Advanced Navigation Technology
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• v.18 no.5
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• pp.494-500
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• 2014

Recently the leak of personal information from in-house and contract-managed companies has been continually increasing, which leads a regular observation on outsourcing companies that perform the personal information management system to prevent dangers from the leakage, stolen and loss of personal information. However, analyzing many numbers of computers in limited time has found few difficulties in some circumstances-such as outsourcing companies that own computers that have personal information system or task continuities that being related to company's profits. For the reason, it is necessary to select an object of examination through identifying a high-risk of personal data leak. In this paper, this study will formulate a proposal for the selection of high-risk subjects, which is based on the user interface, by digital forensic. The study designs the integrated analysis tool and demonstrates the effects of the tool through the test results.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.10a
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• pp.1033-1036
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• 2002

Wafer bonding methods such as fusion and anodic bonding suffer from high temperature treatment, long processing time, and possible damage to the micro-scale sensor or actuators. In the localized bonding process, beating was conducted locally while the whole wafer is maintained at a relatively low temperature. But previous research of localized heating has some problems, such as non-uniform soldering due to non-uniform heating and micro crack formation on the glass capsule by thermal stress effect. To address this non-uniformity problem, a new heater configuration is being proposed. By keeping several points on the heater strip at calculated and constant potential, more uniform heating, hence more reliable wafer bonding could be achieved. The proposed scheme has been successfully demonstrated, and the result shows that it will be very useful in hermetic packaging. Less than 0.2 ㎫ contact Pressure were used for bonding with 150 ㎃ current input for 50${\mu}{\textrm}{m}$ width, 2${\mu}{\textrm}{m}$ height and 8mm $\times$ 8mm, 5mm$\times$5mm, 3mm $\times$ 3mm sized phosphorus-doped poly-silicon micro heater. The temperature can be raised at the bonding region to 80$0^{\circ}C$, and it was enough to achieve a strong and reliable bonding in 3minutes. The IR camera test results show improved uniformity in heat distribution compared with conventional micro heaters. For gross leak check, IPA (Isopropanol Alcohol) was used. Since IPA has better wetability than water, it can easily penetrate small openings, and is more suitable for gross leak check. The pass ratio of bonded dies was 70%, for conventional localized heating, and 85% for newly developed FP scheme. The bonding strength was more than 30㎫ for FP scheme packaging, which shows that FP scheme can be a good candidate for micro scale hermetic packaging.

• Journal of the Korean Geotechnical Society
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• v.33 no.12
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• pp.115-125
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• 2017

PHC-W earth retaining wall could be constructed continuously. Various retaining wall methods such as C.I.P. etc. method require separate waterproof method. However, the PHC-W retaining wall method prevents leakage of groundwater by inserting a waterproofing material at connection part between 2 PHC piles. In this study, the experimental study on 3 waterproofing method for PHC-W retaining wall was conducted at the model pressure chamber. In the method using textile with 1-liquid type and 2-liquid type urethane, rapid leak occurred at the pressure of 120 kPa and 140 kPa or more. In the method of textile with grouting, rapid leak occurred at the pressure of 120 kPa or more, however, in this method, the rapid leakage happened at the top part and the bottom part reinforced with urethane.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.24 no.9
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• pp.1231-1240
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• 2020

Water pipes are laid on the ground, making it impossible to visually detect leaks due to aging of pipes, and technology to detect leaks in pipes is mainly used to detect leaks in pipes by detecting leaks. In this paper, two accelerometers were attached to both ends of the constant water piping to calculate the time difference between the acquired data to detect leakage points. The leak test of piping was performed by installing valves at 4.3m, 8.6m, and 12.9m points on piping 17.2m, and changing the development rate of valves to 30% and 70%. Leakage can be detected for pressure drop in piping, which is 30% and 70% open valve. It is very important to detect leakage in the early stage, and it is judged that detection of the initial leak point from the algorithm applied in this paper will be possible.

• Korean Journal of Hazardous Materials
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• v.2 no.1
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• pp.31-37
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• 2014

Since the unprecedented hydrogen fluoride leak accident in 2012, there has been growing demand for customized technical information for rapid response and chemical accident management agencies including the Ministry of Environment, the National Emergency Management Agency, and the National Police Agency need more information on chemicals and accident management. In this regard, this study aims to provide reliable technical data and guidelines to initial response agencies, similar to accident management technical reports of the US and Canada. In this study, we conducted a questionnaire survey and interviews on initial response agencies like fire stations, police stations, and local governments to identify new information items for appropriate initial response and improvements of current guidelines. We also collected and reviewed the Canada's TIPS, US EPA's hydrogen fluoride documents, domestic and foreign literature on applicability tests of control chemicals, and interview data, and then produced items to be listed in the technical guidelines. In addition, to establish database of on-site technical information, we carried out applicability tests for accident control data including ① emergency shut down devide, safety guard, shut down valve, ground connection, dyke, transfer pipe, scrubber, and sensor; ② literature and field survey on distribution type and transportation/storage characteristics (container identification, valve, ground connection, etc.); ③ classification and identification of storage/transportation facilities and emergency management methodslike leak prevention, chemicals control, and cutoff or bypass of rain drainage; ④ domestic/foreign analysis methods and environmental standards including portable detection methods, test standards, and exposure limits; and ⑤ comparison/evaluation of neutralization efficiency of control chemicals on toxic substances.

• Journal of Hydrogen and New Energy
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• v.34 no.5
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• pp.526-534
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• 2023

To evaluate the risk of leakage when using liquid hydrogen, a leakage test was conducted using liquid nitrogen in an outdoor environment rather than a laboratory environment. To assume a real-scale continuous leak, liquid nitrogen was allowed to leak for 5 minutes through a pipe with a diameter of 25.4 mm at a design spill rate of 60 L/min. The measurement system consisted of devices for climate conditions, LN2 spread and vapor clouds. The main experimental results are the liquid pool radius and the concentration of vapor cloud, and the radius of the liquid pool was compared with the numerical analysis results.

• Journal of Hydrogen and New Energy
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• v.35 no.4
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• pp.353-362
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• 2024

In this study, several studies were conducted on the construction of gas conversion process system for a pilot plant using a small-scale hydrogen liquefaction system. The pilot plant considered in this study includes a liquefier, a storage tank, an evaporator, a gas booster, and a gas storage tank. First, the suspected leak area of the container was checked using the sprayed method of helium gas. The small-scale hydrogen liquefaction system was designed based on the analysis results of the pre-cooling system and the liquefaction system. Additionally, the program was developed to maintain pressure within vessel for an automatic production of liquid hydrogen. The evaporator for liquid hydrogen was manufactured based on the designed analysis data, and the pollution of gas in the vessel was analyzed through a gas recovery line system.

• Journal of Ocean Engineering and Technology
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• v.12 no.1
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• pp.50-57
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• 1998

The leak before break(LBB) concept is generalized on the design of LNG tanks, pressure vessels and nuclear reactor in that any leakage of containment, in whatever amount, will not result in catastropic failure. For this purpose it is necessary to determine the surface crack shape, the opening displacement and the risk of catastropic brittle fracture when it becomes a through crack. In this study the crack propagation behavior of surface flaws and the crack opening displacement of through cracks under combined membrane and bending stresses were investigated with fatigue tests and fracture toughness test of aluminium alloy A5083-O. And fracture mechanics analysis of the crack opening displacement of through cracks were made in order to develop a new model expressing the behaviors of COD under combined membrane and bending stresses.

• Proceedings of the KIEE Conference
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• 1991.07a
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• pp.304-309
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• 1991

We introduce the trend, of several countries, to the gas insulated transformer recently coming into the spot light by the advantages of less weight, GIS-lization, low noise level and easiness to decrease environmental pollutions, and the insulating gases. the cooling media and the insulating materials used for transformer. Hereinafter, additively the design of proto type $SF_6$ gas insulated transformer (insulation, cooling), which was developed by us(HICO) from 1987. 2 through 1990. 3, the manufacturing processes(leak protection, pressure, drying of main body), the accessories, the protective system, the cooling system, the method and the results of test and the evaluation of economics compared with conventional oil-filled transformer are represented.

• Journal of Mechanical Science and Technology
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• v.17 no.11
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• pp.1599-1607
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• 2003

The characteristics of elastic waves emanated from crack initiation in 6061 aluminum alloy subjected to fatigue loading are investigated through experiments. The objective of the study is to determine the differences in the properties of the signals generated from fatigue test and also to examine if the sources of the waves could be identified from the temporal and spectral characteristics of the acoustic emission (AE) waveforms. The signals are recorded using nonresonant, flat, broadband transducers attached to the surface of the alloy specimens. The time dependence and power spectra of the signals recorded during the tests were examined and classified according to their special features. Six distinct types of signals were observed. The waveforms and their power spectra were found to be dependent on the crack propagation stage and the type of fracture associated with the signals. The potential application of the approach in health monitoring of structural components using a network of surface mounted broadband sensors is discussed.